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-rw-r--r--vendor/mbedtls/ssl.h5369
1 files changed, 5369 insertions, 0 deletions
diff --git a/vendor/mbedtls/ssl.h b/vendor/mbedtls/ssl.h
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+++ b/vendor/mbedtls/ssl.h
@@ -0,0 +1,5369 @@
+/**
+ * \file ssl.h
+ *
+ * \brief SSL/TLS functions.
+ */
+/*
+ * Copyright The Mbed TLS Contributors
+ * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+#ifndef MBEDTLS_SSL_H
+#define MBEDTLS_SSL_H
+#include "mbedtls/platform_util.h"
+#include "mbedtls/private_access.h"
+
+#include "mbedtls/build_info.h"
+
+#include "mbedtls/bignum.h"
+#include "mbedtls/ecp.h"
+
+#include "mbedtls/ssl_ciphersuites.h"
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#include "mbedtls/x509_crt.h"
+#include "mbedtls/x509_crl.h"
+#endif
+
+#if defined(MBEDTLS_DHM_C)
+#include "mbedtls/dhm.h"
+#endif
+
+#include "mbedtls/md.h"
+
+#if defined(MBEDTLS_KEY_EXCHANGE_SOME_ECDH_OR_ECDHE_ANY_ENABLED)
+#include "mbedtls/ecdh.h"
+#endif
+
+#if defined(MBEDTLS_HAVE_TIME)
+#include "mbedtls/platform_time.h"
+#endif
+
+#include "psa/crypto.h"
+
+/*
+ * SSL Error codes
+ */
+/** A cryptographic operation is in progress. Try again later. */
+#define MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS -0x7000
+/** The requested feature is not available. */
+#define MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE -0x7080
+/** Bad input parameters to function. */
+#define MBEDTLS_ERR_SSL_BAD_INPUT_DATA -0x7100
+/** Verification of the message MAC failed. */
+#define MBEDTLS_ERR_SSL_INVALID_MAC -0x7180
+/** An invalid SSL record was received. */
+#define MBEDTLS_ERR_SSL_INVALID_RECORD -0x7200
+/** The connection indicated an EOF. */
+#define MBEDTLS_ERR_SSL_CONN_EOF -0x7280
+/** A message could not be parsed due to a syntactic error. */
+#define MBEDTLS_ERR_SSL_DECODE_ERROR -0x7300
+/* Error space gap */
+/** No RNG was provided to the SSL module. */
+#define MBEDTLS_ERR_SSL_NO_RNG -0x7400
+/** No client certification received from the client, but required by the authentication mode. */
+#define MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE -0x7480
+/** Client received an extended server hello containing an unsupported extension */
+#define MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION -0x7500
+/** No ALPN protocols supported that the client advertises */
+#define MBEDTLS_ERR_SSL_NO_APPLICATION_PROTOCOL -0x7580
+/** The own private key or pre-shared key is not set, but needed. */
+#define MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED -0x7600
+/** No CA Chain is set, but required to operate. */
+#define MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED -0x7680
+/** An unexpected message was received from our peer. */
+#define MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE -0x7700
+/** A fatal alert message was received from our peer. */
+#define MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE -0x7780
+/** No server could be identified matching the client's SNI. */
+#define MBEDTLS_ERR_SSL_UNRECOGNIZED_NAME -0x7800
+/** The peer notified us that the connection is going to be closed. */
+#define MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY -0x7880
+/* Error space gap */
+/* Error space gap */
+/** Processing of the Certificate handshake message failed. */
+#define MBEDTLS_ERR_SSL_BAD_CERTIFICATE -0x7A00
+/* Error space gap */
+/**
+ * Received NewSessionTicket Post Handshake Message.
+ * This error code is experimental and may be changed or removed without notice.
+ */
+#define MBEDTLS_ERR_SSL_RECEIVED_NEW_SESSION_TICKET -0x7B00
+/** Not possible to read early data */
+#define MBEDTLS_ERR_SSL_CANNOT_READ_EARLY_DATA -0x7B80
+/** Not possible to write early data */
+#define MBEDTLS_ERR_SSL_CANNOT_WRITE_EARLY_DATA -0x7C00
+/* Error space gap */
+/* Error space gap */
+/* Error space gap */
+/* Error space gap */
+/** Cache entry not found */
+#define MBEDTLS_ERR_SSL_CACHE_ENTRY_NOT_FOUND -0x7E80
+/** Memory allocation failed */
+#define MBEDTLS_ERR_SSL_ALLOC_FAILED -0x7F00
+/** Hardware acceleration function returned with error */
+#define MBEDTLS_ERR_SSL_HW_ACCEL_FAILED -0x7F80
+/** Hardware acceleration function skipped / left alone data */
+#define MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH -0x6F80
+/** Handshake protocol not within min/max boundaries */
+#define MBEDTLS_ERR_SSL_BAD_PROTOCOL_VERSION -0x6E80
+/** The handshake negotiation failed. */
+#define MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE -0x6E00
+/** Session ticket has expired. */
+#define MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED -0x6D80
+/** Public key type mismatch (eg, asked for RSA key exchange and presented EC key) */
+#define MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH -0x6D00
+/** Unknown identity received (eg, PSK identity) */
+#define MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY -0x6C80
+/** Internal error (eg, unexpected failure in lower-level module) */
+#define MBEDTLS_ERR_SSL_INTERNAL_ERROR -0x6C00
+/** A counter would wrap (eg, too many messages exchanged). */
+#define MBEDTLS_ERR_SSL_COUNTER_WRAPPING -0x6B80
+/** Unexpected message at ServerHello in renegotiation. */
+#define MBEDTLS_ERR_SSL_WAITING_SERVER_HELLO_RENEGO -0x6B00
+/** DTLS client must retry for hello verification */
+#define MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED -0x6A80
+/** A buffer is too small to receive or write a message */
+#define MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL -0x6A00
+/* Error space gap */
+/** No data of requested type currently available on underlying transport. */
+#define MBEDTLS_ERR_SSL_WANT_READ -0x6900
+/** Connection requires a write call. */
+#define MBEDTLS_ERR_SSL_WANT_WRITE -0x6880
+/** The operation timed out. */
+#define MBEDTLS_ERR_SSL_TIMEOUT -0x6800
+/** The client initiated a reconnect from the same port. */
+#define MBEDTLS_ERR_SSL_CLIENT_RECONNECT -0x6780
+/** Record header looks valid but is not expected. */
+#define MBEDTLS_ERR_SSL_UNEXPECTED_RECORD -0x6700
+/** The alert message received indicates a non-fatal error. */
+#define MBEDTLS_ERR_SSL_NON_FATAL -0x6680
+/** A field in a message was incorrect or inconsistent with other fields. */
+#define MBEDTLS_ERR_SSL_ILLEGAL_PARAMETER -0x6600
+/** Internal-only message signaling that further message-processing should be done */
+#define MBEDTLS_ERR_SSL_CONTINUE_PROCESSING -0x6580
+/** The asynchronous operation is not completed yet. */
+#define MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS -0x6500
+/** Internal-only message signaling that a message arrived early. */
+#define MBEDTLS_ERR_SSL_EARLY_MESSAGE -0x6480
+/* Error space gap */
+/* Error space gap */
+/* Error space gap */
+/* Error space gap */
+/* Error space gap */
+/* Error space gap */
+/* Error space gap */
+/* Error space gap */
+/** An encrypted DTLS-frame with an unexpected CID was received. */
+#define MBEDTLS_ERR_SSL_UNEXPECTED_CID -0x6000
+/** An operation failed due to an unexpected version or configuration. */
+#define MBEDTLS_ERR_SSL_VERSION_MISMATCH -0x5F00
+/** Invalid value in SSL config */
+#define MBEDTLS_ERR_SSL_BAD_CONFIG -0x5E80
+
+/*
+ * Constants from RFC 8446 for TLS 1.3 PSK modes
+ *
+ * Those are used in the Pre-Shared Key Exchange Modes extension.
+ * See Section 4.2.9 in RFC 8446.
+ */
+#define MBEDTLS_SSL_TLS1_3_PSK_MODE_PURE 0 /* Pure PSK-based exchange */
+#define MBEDTLS_SSL_TLS1_3_PSK_MODE_ECDHE 1 /* PSK+ECDHE-based exchange */
+
+/*
+ * TLS 1.3 NamedGroup values
+ *
+ * From RF 8446
+ * enum {
+ * // Elliptic Curve Groups (ECDHE)
+ * secp256r1(0x0017), secp384r1(0x0018), secp521r1(0x0019),
+ * x25519(0x001D), x448(0x001E),
+ * // Finite Field Groups (DHE)
+ * ffdhe2048(0x0100), ffdhe3072(0x0101), ffdhe4096(0x0102),
+ * ffdhe6144(0x0103), ffdhe8192(0x0104),
+ * // Reserved Code Points
+ * ffdhe_private_use(0x01FC..0x01FF),
+ * ecdhe_private_use(0xFE00..0xFEFF),
+ * (0xFFFF)
+ * } NamedGroup;
+ *
+ */
+
+/* Elliptic Curve Groups (ECDHE) */
+#define MBEDTLS_SSL_IANA_TLS_GROUP_NONE 0
+#define MBEDTLS_SSL_IANA_TLS_GROUP_SECP192K1 0x0012
+#define MBEDTLS_SSL_IANA_TLS_GROUP_SECP192R1 0x0013
+#define MBEDTLS_SSL_IANA_TLS_GROUP_SECP224K1 0x0014
+#define MBEDTLS_SSL_IANA_TLS_GROUP_SECP224R1 0x0015
+#define MBEDTLS_SSL_IANA_TLS_GROUP_SECP256K1 0x0016
+#define MBEDTLS_SSL_IANA_TLS_GROUP_SECP256R1 0x0017
+#define MBEDTLS_SSL_IANA_TLS_GROUP_SECP384R1 0x0018
+#define MBEDTLS_SSL_IANA_TLS_GROUP_SECP521R1 0x0019
+#define MBEDTLS_SSL_IANA_TLS_GROUP_BP256R1 0x001A
+#define MBEDTLS_SSL_IANA_TLS_GROUP_BP384R1 0x001B
+#define MBEDTLS_SSL_IANA_TLS_GROUP_BP512R1 0x001C
+#define MBEDTLS_SSL_IANA_TLS_GROUP_X25519 0x001D
+#define MBEDTLS_SSL_IANA_TLS_GROUP_X448 0x001E
+/* Finite Field Groups (DHE) */
+#define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE2048 0x0100
+#define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE3072 0x0101
+#define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE4096 0x0102
+#define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE6144 0x0103
+#define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE8192 0x0104
+
+/*
+ * TLS 1.3 Key Exchange Modes
+ *
+ * Mbed TLS internal identifiers for use with the SSL configuration API
+ * mbedtls_ssl_conf_tls13_key_exchange_modes().
+ */
+
+#define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK (1u << 0) /*!< Pure-PSK TLS 1.3 key exchange,
+ * encompassing both externally agreed PSKs
+ * as well as resumption PSKs. */
+#define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL (1u << 1) /*!< Pure-Ephemeral TLS 1.3 key exchanges,
+ * including for example ECDHE and DHE
+ * key exchanges. */
+#define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL (1u << 2) /*!< PSK-Ephemeral TLS 1.3 key exchanges,
+ * using both a PSK and an ephemeral
+ * key exchange. */
+
+/* Convenience macros for sets of key exchanges. */
+#define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_ALL \
+ (MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK | \
+ MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL | \
+ MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL) /*!< All TLS 1.3 key exchanges */
+#define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL \
+ (MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK | \
+ MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL) /*!< All PSK-based TLS 1.3 key exchanges */
+#define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ALL \
+ (MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL | \
+ MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL) /*!< All ephemeral TLS 1.3 key exchanges */
+
+#define MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_NONE (0)
+
+/*
+ * Various constants
+ */
+
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+/* These are the high and low bytes of ProtocolVersion as defined by:
+ * - RFC 5246: ProtocolVersion version = { 3, 3 }; // TLS v1.2
+ * - RFC 8446: see section 4.2.1
+ */
+#define MBEDTLS_SSL_MAJOR_VERSION_3 3
+#define MBEDTLS_SSL_MINOR_VERSION_3 3 /*!< TLS v1.2 */
+#define MBEDTLS_SSL_MINOR_VERSION_4 4 /*!< TLS v1.3 */
+#endif /* MBEDTLS_DEPRECATED_REMOVED */
+
+#define MBEDTLS_SSL_TRANSPORT_STREAM 0 /*!< TLS */
+#define MBEDTLS_SSL_TRANSPORT_DATAGRAM 1 /*!< DTLS */
+
+#define MBEDTLS_SSL_MAX_HOST_NAME_LEN 255 /*!< Maximum host name defined in RFC 1035 */
+#define MBEDTLS_SSL_MAX_ALPN_NAME_LEN 255 /*!< Maximum size in bytes of a protocol name in alpn ext., RFC 7301 */
+
+#define MBEDTLS_SSL_MAX_ALPN_LIST_LEN 65535 /*!< Maximum size in bytes of list in alpn ext., RFC 7301 */
+
+/* RFC 6066 section 4, see also mfl_code_to_length in ssl_tls.c
+ * NONE must be zero so that memset()ing structure to zero works */
+#define MBEDTLS_SSL_MAX_FRAG_LEN_NONE 0 /*!< don't use this extension */
+#define MBEDTLS_SSL_MAX_FRAG_LEN_512 1 /*!< MaxFragmentLength 2^9 */
+#define MBEDTLS_SSL_MAX_FRAG_LEN_1024 2 /*!< MaxFragmentLength 2^10 */
+#define MBEDTLS_SSL_MAX_FRAG_LEN_2048 3 /*!< MaxFragmentLength 2^11 */
+#define MBEDTLS_SSL_MAX_FRAG_LEN_4096 4 /*!< MaxFragmentLength 2^12 */
+#define MBEDTLS_SSL_MAX_FRAG_LEN_INVALID 5 /*!< first invalid value */
+
+#define MBEDTLS_SSL_IS_CLIENT 0
+#define MBEDTLS_SSL_IS_SERVER 1
+
+#define MBEDTLS_SSL_EXTENDED_MS_DISABLED 0
+#define MBEDTLS_SSL_EXTENDED_MS_ENABLED 1
+
+#define MBEDTLS_SSL_CID_DISABLED 0
+#define MBEDTLS_SSL_CID_ENABLED 1
+
+#define MBEDTLS_SSL_ETM_DISABLED 0
+#define MBEDTLS_SSL_ETM_ENABLED 1
+
+#define MBEDTLS_SSL_COMPRESS_NULL 0
+
+#define MBEDTLS_SSL_VERIFY_NONE 0
+#define MBEDTLS_SSL_VERIFY_OPTIONAL 1
+#define MBEDTLS_SSL_VERIFY_REQUIRED 2
+#define MBEDTLS_SSL_VERIFY_UNSET 3 /* Used only for sni_authmode */
+
+#define MBEDTLS_SSL_LEGACY_RENEGOTIATION 0
+#define MBEDTLS_SSL_SECURE_RENEGOTIATION 1
+
+#define MBEDTLS_SSL_RENEGOTIATION_DISABLED 0
+#define MBEDTLS_SSL_RENEGOTIATION_ENABLED 1
+
+#define MBEDTLS_SSL_ANTI_REPLAY_DISABLED 0
+#define MBEDTLS_SSL_ANTI_REPLAY_ENABLED 1
+
+#define MBEDTLS_SSL_RENEGOTIATION_NOT_ENFORCED -1
+#define MBEDTLS_SSL_RENEGO_MAX_RECORDS_DEFAULT 16
+
+#define MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION 0
+#define MBEDTLS_SSL_LEGACY_ALLOW_RENEGOTIATION 1
+#define MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE 2
+
+#define MBEDTLS_SSL_TRUNC_HMAC_DISABLED 0
+#define MBEDTLS_SSL_TRUNC_HMAC_ENABLED 1
+#define MBEDTLS_SSL_TRUNCATED_HMAC_LEN 10 /* 80 bits, rfc 6066 section 7 */
+
+#define MBEDTLS_SSL_SESSION_TICKETS_DISABLED 0
+#define MBEDTLS_SSL_SESSION_TICKETS_ENABLED 1
+
+#define MBEDTLS_SSL_PRESET_DEFAULT 0
+#define MBEDTLS_SSL_PRESET_SUITEB 2
+
+#define MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED 1
+#define MBEDTLS_SSL_CERT_REQ_CA_LIST_DISABLED 0
+
+#define MBEDTLS_SSL_EARLY_DATA_DISABLED 0
+#define MBEDTLS_SSL_EARLY_DATA_ENABLED 1
+
+#define MBEDTLS_SSL_DTLS_SRTP_MKI_UNSUPPORTED 0
+#define MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED 1
+
+#define MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_CLIENT 1
+#define MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_SERVER 0
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
+#if defined(PSA_WANT_ALG_SHA_384)
+#define MBEDTLS_SSL_TLS1_3_TICKET_RESUMPTION_KEY_LEN 48
+#elif defined(PSA_WANT_ALG_SHA_256)
+#define MBEDTLS_SSL_TLS1_3_TICKET_RESUMPTION_KEY_LEN 32
+#endif
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 && MBEDTLS_SSL_SESSION_TICKETS */
+/*
+ * Default range for DTLS retransmission timer value, in milliseconds.
+ * RFC 6347 4.2.4.1 says from 1 second to 60 seconds.
+ */
+#define MBEDTLS_SSL_DTLS_TIMEOUT_DFL_MIN 1000
+#define MBEDTLS_SSL_DTLS_TIMEOUT_DFL_MAX 60000
+
+/**
+ * \name SECTION: Module settings
+ *
+ * The configuration options you can set for this module are in this section.
+ * Either change them in mbedtls_config.h or define them on the compiler command line.
+ * \{
+ */
+
+/*
+ * Maximum fragment length in bytes,
+ * determines the size of each of the two internal I/O buffers.
+ *
+ * Note: the RFC defines the default size of SSL / TLS messages. If you
+ * change the value here, other clients / servers may not be able to
+ * communicate with you anymore. Only change this value if you control
+ * both sides of the connection and have it reduced at both sides, or
+ * if you're using the Max Fragment Length extension and you know all your
+ * peers are using it too!
+ */
+#if !defined(MBEDTLS_SSL_IN_CONTENT_LEN)
+#define MBEDTLS_SSL_IN_CONTENT_LEN 16384
+#endif
+
+#if !defined(MBEDTLS_SSL_OUT_CONTENT_LEN)
+#define MBEDTLS_SSL_OUT_CONTENT_LEN 16384
+#endif
+
+/*
+ * Maximum number of heap-allocated bytes for the purpose of
+ * DTLS handshake message reassembly and future message buffering.
+ */
+#if !defined(MBEDTLS_SSL_DTLS_MAX_BUFFERING)
+#define MBEDTLS_SSL_DTLS_MAX_BUFFERING 32768
+#endif
+
+/*
+ * Maximum length of CIDs for incoming and outgoing messages.
+ */
+#if !defined(MBEDTLS_SSL_CID_IN_LEN_MAX)
+#define MBEDTLS_SSL_CID_IN_LEN_MAX 32
+#endif
+
+#if !defined(MBEDTLS_SSL_CID_OUT_LEN_MAX)
+#define MBEDTLS_SSL_CID_OUT_LEN_MAX 32
+#endif
+
+#if !defined(MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY)
+#define MBEDTLS_SSL_CID_TLS1_3_PADDING_GRANULARITY 16
+#endif
+
+#if !defined(MBEDTLS_SSL_MAX_EARLY_DATA_SIZE)
+#define MBEDTLS_SSL_MAX_EARLY_DATA_SIZE 1024
+#endif
+
+#if !defined(MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE)
+#define MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE 6000
+#endif
+
+#if !defined(MBEDTLS_SSL_TLS1_3_TICKET_NONCE_LENGTH)
+#define MBEDTLS_SSL_TLS1_3_TICKET_NONCE_LENGTH 32
+#endif
+
+#if !defined(MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS)
+#define MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS 1
+#endif
+
+/** \} name SECTION: Module settings */
+
+/*
+ * Default to standard CID mode
+ */
+#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID) && \
+ !defined(MBEDTLS_SSL_DTLS_CONNECTION_ID_COMPAT)
+#define MBEDTLS_SSL_DTLS_CONNECTION_ID_COMPAT 0
+#endif
+
+/*
+ * Length of the verify data for secure renegotiation
+ */
+#define MBEDTLS_SSL_VERIFY_DATA_MAX_LEN 12
+
+/*
+ * Signaling ciphersuite values (SCSV)
+ */
+#define MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO 0xFF /**< renegotiation info ext */
+
+/*
+ * Supported Signature and Hash algorithms (For TLS 1.2)
+ * RFC 5246 section 7.4.1.4.1
+ */
+#define MBEDTLS_SSL_HASH_NONE 0
+#define MBEDTLS_SSL_HASH_MD5 1
+#define MBEDTLS_SSL_HASH_SHA1 2
+#define MBEDTLS_SSL_HASH_SHA224 3
+#define MBEDTLS_SSL_HASH_SHA256 4
+#define MBEDTLS_SSL_HASH_SHA384 5
+#define MBEDTLS_SSL_HASH_SHA512 6
+
+#define MBEDTLS_SSL_SIG_ANON 0
+#define MBEDTLS_SSL_SIG_RSA 1
+#define MBEDTLS_SSL_SIG_ECDSA 3
+
+/*
+ * TLS 1.3 signature algorithms
+ * RFC 8446, Section 4.2.2
+ */
+
+/* RSASSA-PKCS1-v1_5 algorithms */
+#define MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA256 0x0401
+#define MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA384 0x0501
+#define MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA512 0x0601
+
+/* ECDSA algorithms */
+#define MBEDTLS_TLS1_3_SIG_ECDSA_SECP256R1_SHA256 0x0403
+#define MBEDTLS_TLS1_3_SIG_ECDSA_SECP384R1_SHA384 0x0503
+#define MBEDTLS_TLS1_3_SIG_ECDSA_SECP521R1_SHA512 0x0603
+
+/* RSASSA-PSS algorithms with public key OID rsaEncryption */
+#define MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA256 0x0804
+#define MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA384 0x0805
+#define MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA512 0x0806
+
+/* EdDSA algorithms */
+#define MBEDTLS_TLS1_3_SIG_ED25519 0x0807
+#define MBEDTLS_TLS1_3_SIG_ED448 0x0808
+
+/* RSASSA-PSS algorithms with public key OID RSASSA-PSS */
+#define MBEDTLS_TLS1_3_SIG_RSA_PSS_PSS_SHA256 0x0809
+#define MBEDTLS_TLS1_3_SIG_RSA_PSS_PSS_SHA384 0x080A
+#define MBEDTLS_TLS1_3_SIG_RSA_PSS_PSS_SHA512 0x080B
+
+/* LEGACY ALGORITHMS */
+#define MBEDTLS_TLS1_3_SIG_RSA_PKCS1_SHA1 0x0201
+#define MBEDTLS_TLS1_3_SIG_ECDSA_SHA1 0x0203
+
+#define MBEDTLS_TLS1_3_SIG_NONE 0x0
+
+/*
+ * Client Certificate Types
+ * RFC 5246 section 7.4.4 plus RFC 4492 section 5.5
+ */
+#define MBEDTLS_SSL_CERT_TYPE_RSA_SIGN 1
+#define MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN 64
+
+/*
+ * Message, alert and handshake types
+ */
+#define MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC 20
+#define MBEDTLS_SSL_MSG_ALERT 21
+#define MBEDTLS_SSL_MSG_HANDSHAKE 22
+#define MBEDTLS_SSL_MSG_APPLICATION_DATA 23
+#define MBEDTLS_SSL_MSG_CID 25
+
+#define MBEDTLS_SSL_ALERT_LEVEL_WARNING 1
+#define MBEDTLS_SSL_ALERT_LEVEL_FATAL 2
+
+#define MBEDTLS_SSL_ALERT_MSG_CLOSE_NOTIFY 0 /* 0x00 */
+#define MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE 10 /* 0x0A */
+#define MBEDTLS_SSL_ALERT_MSG_BAD_RECORD_MAC 20 /* 0x14 */
+#define MBEDTLS_SSL_ALERT_MSG_DECRYPTION_FAILED 21 /* 0x15 */
+#define MBEDTLS_SSL_ALERT_MSG_RECORD_OVERFLOW 22 /* 0x16 */
+#define MBEDTLS_SSL_ALERT_MSG_DECOMPRESSION_FAILURE 30 /* 0x1E */
+#define MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE 40 /* 0x28 */
+#define MBEDTLS_SSL_ALERT_MSG_NO_CERT 41 /* 0x29 */
+#define MBEDTLS_SSL_ALERT_MSG_BAD_CERT 42 /* 0x2A */
+#define MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT 43 /* 0x2B */
+#define MBEDTLS_SSL_ALERT_MSG_CERT_REVOKED 44 /* 0x2C */
+#define MBEDTLS_SSL_ALERT_MSG_CERT_EXPIRED 45 /* 0x2D */
+#define MBEDTLS_SSL_ALERT_MSG_CERT_UNKNOWN 46 /* 0x2E */
+#define MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER 47 /* 0x2F */
+#define MBEDTLS_SSL_ALERT_MSG_UNKNOWN_CA 48 /* 0x30 */
+#define MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED 49 /* 0x31 */
+#define MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR 50 /* 0x32 */
+#define MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR 51 /* 0x33 */
+#define MBEDTLS_SSL_ALERT_MSG_EXPORT_RESTRICTION 60 /* 0x3C */
+#define MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION 70 /* 0x46 */
+#define MBEDTLS_SSL_ALERT_MSG_INSUFFICIENT_SECURITY 71 /* 0x47 */
+#define MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR 80 /* 0x50 */
+#define MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK 86 /* 0x56 */
+#define MBEDTLS_SSL_ALERT_MSG_USER_CANCELED 90 /* 0x5A */
+#define MBEDTLS_SSL_ALERT_MSG_NO_RENEGOTIATION 100 /* 0x64 */
+#define MBEDTLS_SSL_ALERT_MSG_MISSING_EXTENSION 109 /* 0x6d -- new in TLS 1.3 */
+#define MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_EXT 110 /* 0x6E */
+#define MBEDTLS_SSL_ALERT_MSG_UNRECOGNIZED_NAME 112 /* 0x70 */
+#define MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY 115 /* 0x73 */
+#define MBEDTLS_SSL_ALERT_MSG_CERT_REQUIRED 116 /* 0x74 */
+#define MBEDTLS_SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL 120 /* 0x78 */
+
+#define MBEDTLS_SSL_HS_HELLO_REQUEST 0
+#define MBEDTLS_SSL_HS_CLIENT_HELLO 1
+#define MBEDTLS_SSL_HS_SERVER_HELLO 2
+#define MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST 3
+#define MBEDTLS_SSL_HS_NEW_SESSION_TICKET 4
+#define MBEDTLS_SSL_HS_END_OF_EARLY_DATA 5
+#define MBEDTLS_SSL_HS_ENCRYPTED_EXTENSIONS 8
+#define MBEDTLS_SSL_HS_CERTIFICATE 11
+#define MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE 12
+#define MBEDTLS_SSL_HS_CERTIFICATE_REQUEST 13
+#define MBEDTLS_SSL_HS_SERVER_HELLO_DONE 14
+#define MBEDTLS_SSL_HS_CERTIFICATE_VERIFY 15
+#define MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE 16
+#define MBEDTLS_SSL_HS_FINISHED 20
+#define MBEDTLS_SSL_HS_MESSAGE_HASH 254
+
+/*
+ * TLS extensions
+ */
+#define MBEDTLS_TLS_EXT_SERVERNAME 0
+#define MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME 0
+
+#define MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH 1
+
+#define MBEDTLS_TLS_EXT_TRUNCATED_HMAC 4
+#define MBEDTLS_TLS_EXT_STATUS_REQUEST 5 /* RFC 6066 TLS 1.2 and 1.3 */
+
+#define MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES 10
+#define MBEDTLS_TLS_EXT_SUPPORTED_GROUPS 10 /* RFC 8422,7919 TLS 1.2 and 1.3 */
+#define MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS 11
+
+#define MBEDTLS_TLS_EXT_SIG_ALG 13 /* RFC 8446 TLS 1.3 */
+#define MBEDTLS_TLS_EXT_USE_SRTP 14
+#define MBEDTLS_TLS_EXT_HEARTBEAT 15 /* RFC 6520 TLS 1.2 and 1.3 */
+#define MBEDTLS_TLS_EXT_ALPN 16
+
+#define MBEDTLS_TLS_EXT_SCT 18 /* RFC 6962 TLS 1.2 and 1.3 */
+#define MBEDTLS_TLS_EXT_CLI_CERT_TYPE 19 /* RFC 7250 TLS 1.2 and 1.3 */
+#define MBEDTLS_TLS_EXT_SERV_CERT_TYPE 20 /* RFC 7250 TLS 1.2 and 1.3 */
+#define MBEDTLS_TLS_EXT_PADDING 21 /* RFC 7685 TLS 1.2 and 1.3 */
+#define MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC 22 /* 0x16 */
+#define MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET 0x0017 /* 23 */
+
+#define MBEDTLS_TLS_EXT_RECORD_SIZE_LIMIT 28 /* RFC 8449 (implemented for TLS 1.3 only) */
+
+#define MBEDTLS_TLS_EXT_SESSION_TICKET 35
+
+#define MBEDTLS_TLS_EXT_PRE_SHARED_KEY 41 /* RFC 8446 TLS 1.3 */
+#define MBEDTLS_TLS_EXT_EARLY_DATA 42 /* RFC 8446 TLS 1.3 */
+#define MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS 43 /* RFC 8446 TLS 1.3 */
+#define MBEDTLS_TLS_EXT_COOKIE 44 /* RFC 8446 TLS 1.3 */
+#define MBEDTLS_TLS_EXT_PSK_KEY_EXCHANGE_MODES 45 /* RFC 8446 TLS 1.3 */
+
+#define MBEDTLS_TLS_EXT_CERT_AUTH 47 /* RFC 8446 TLS 1.3 */
+#define MBEDTLS_TLS_EXT_OID_FILTERS 48 /* RFC 8446 TLS 1.3 */
+#define MBEDTLS_TLS_EXT_POST_HANDSHAKE_AUTH 49 /* RFC 8446 TLS 1.3 */
+#define MBEDTLS_TLS_EXT_SIG_ALG_CERT 50 /* RFC 8446 TLS 1.3 */
+#define MBEDTLS_TLS_EXT_KEY_SHARE 51 /* RFC 8446 TLS 1.3 */
+
+#if MBEDTLS_SSL_DTLS_CONNECTION_ID_COMPAT == 0
+#define MBEDTLS_TLS_EXT_CID 54 /* RFC 9146 DTLS 1.2 CID */
+#else
+#define MBEDTLS_TLS_EXT_CID 254 /* Pre-RFC 9146 DTLS 1.2 CID */
+#endif
+
+#define MBEDTLS_TLS_EXT_ECJPAKE_KKPP 256 /* experimental */
+
+#define MBEDTLS_TLS_EXT_RENEGOTIATION_INFO 0xFF01
+
+/*
+ * Size defines
+ */
+#if !defined(MBEDTLS_PSK_MAX_LEN)
+/*
+ * If the library supports TLS 1.3 tickets and the cipher suite
+ * TLS1-3-AES-256-GCM-SHA384, set the PSK maximum length to 48 instead of 32.
+ * That way, the TLS 1.3 client and server are able to resume sessions where
+ * the cipher suite is TLS1-3-AES-256-GCM-SHA384 (pre-shared keys are 48
+ * bytes long in that case).
+ */
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && \
+ defined(MBEDTLS_SSL_SESSION_TICKETS) && \
+ defined(MBEDTLS_AES_C) && defined(MBEDTLS_GCM_C) && \
+ defined(MBEDTLS_MD_CAN_SHA384)
+#define MBEDTLS_PSK_MAX_LEN 48 /* 384 bits */
+#else
+#define MBEDTLS_PSK_MAX_LEN 32 /* 256 bits */
+#endif
+#endif /* !MBEDTLS_PSK_MAX_LEN */
+
+/* Dummy type used only for its size */
+union mbedtls_ssl_premaster_secret {
+ unsigned char dummy; /* Make the union non-empty even with SSL disabled */
+#if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
+ unsigned char _pms_rsa[48]; /* RFC 5246 8.1.1 */
+#endif
+#if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)
+ unsigned char _pms_dhm[MBEDTLS_MPI_MAX_SIZE]; /* RFC 5246 8.1.2 */
+#endif
+#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED) || \
+ defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED) || \
+ defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED) || \
+ defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
+ unsigned char _pms_ecdh[MBEDTLS_ECP_MAX_BYTES]; /* RFC 4492 5.10 */
+#endif
+#if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
+ unsigned char _pms_psk[4 + 2 * MBEDTLS_PSK_MAX_LEN]; /* RFC 4279 2 */
+#endif
+#if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
+ unsigned char _pms_dhe_psk[4 + MBEDTLS_MPI_MAX_SIZE
+ + MBEDTLS_PSK_MAX_LEN]; /* RFC 4279 3 */
+#endif
+#if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
+ unsigned char _pms_rsa_psk[52 + MBEDTLS_PSK_MAX_LEN]; /* RFC 4279 4 */
+#endif
+#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
+ unsigned char _pms_ecdhe_psk[4 + MBEDTLS_ECP_MAX_BYTES
+ + MBEDTLS_PSK_MAX_LEN]; /* RFC 5489 2 */
+#endif
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+ unsigned char _pms_ecjpake[32]; /* Thread spec: SHA-256 output */
+#endif
+};
+
+#define MBEDTLS_PREMASTER_SIZE sizeof(union mbedtls_ssl_premaster_secret)
+
+#define MBEDTLS_TLS1_3_MD_MAX_SIZE PSA_HASH_MAX_SIZE
+
+
+/* Length in number of bytes of the TLS sequence number */
+#define MBEDTLS_SSL_SEQUENCE_NUMBER_LEN 8
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * SSL state machine
+ */
+typedef enum {
+ MBEDTLS_SSL_HELLO_REQUEST,
+ MBEDTLS_SSL_CLIENT_HELLO,
+ MBEDTLS_SSL_SERVER_HELLO,
+ MBEDTLS_SSL_SERVER_CERTIFICATE,
+ MBEDTLS_SSL_SERVER_KEY_EXCHANGE,
+ MBEDTLS_SSL_CERTIFICATE_REQUEST,
+ MBEDTLS_SSL_SERVER_HELLO_DONE,
+ MBEDTLS_SSL_CLIENT_CERTIFICATE,
+ MBEDTLS_SSL_CLIENT_KEY_EXCHANGE,
+ MBEDTLS_SSL_CERTIFICATE_VERIFY,
+ MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC,
+ MBEDTLS_SSL_CLIENT_FINISHED,
+ MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC,
+ MBEDTLS_SSL_SERVER_FINISHED,
+ MBEDTLS_SSL_FLUSH_BUFFERS,
+ MBEDTLS_SSL_HANDSHAKE_WRAPUP,
+
+ MBEDTLS_SSL_NEW_SESSION_TICKET,
+ MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT,
+ MBEDTLS_SSL_HELLO_RETRY_REQUEST,
+ MBEDTLS_SSL_ENCRYPTED_EXTENSIONS,
+ MBEDTLS_SSL_END_OF_EARLY_DATA,
+ MBEDTLS_SSL_CLIENT_CERTIFICATE_VERIFY,
+ MBEDTLS_SSL_CLIENT_CCS_AFTER_SERVER_FINISHED,
+ MBEDTLS_SSL_CLIENT_CCS_BEFORE_2ND_CLIENT_HELLO,
+ MBEDTLS_SSL_SERVER_CCS_AFTER_SERVER_HELLO,
+ MBEDTLS_SSL_CLIENT_CCS_AFTER_CLIENT_HELLO,
+ MBEDTLS_SSL_SERVER_CCS_AFTER_HELLO_RETRY_REQUEST,
+ MBEDTLS_SSL_HANDSHAKE_OVER,
+ MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET,
+ MBEDTLS_SSL_TLS1_3_NEW_SESSION_TICKET_FLUSH,
+}
+mbedtls_ssl_states;
+
+/**
+ * \brief Callback type: send data on the network.
+ *
+ * \note That callback may be either blocking or non-blocking.
+ *
+ * \param ctx Context for the send callback (typically a file descriptor)
+ * \param buf Buffer holding the data to send
+ * \param len Length of the data to send
+ *
+ * \return The callback must return the number of bytes sent if any,
+ * or a non-zero error code.
+ * If performing non-blocking I/O, \c MBEDTLS_ERR_SSL_WANT_WRITE
+ * must be returned when the operation would block.
+ *
+ * \note The callback is allowed to send fewer bytes than requested.
+ * It must always return the number of bytes actually sent.
+ */
+typedef int mbedtls_ssl_send_t(void *ctx,
+ const unsigned char *buf,
+ size_t len);
+
+/**
+ * \brief Callback type: receive data from the network.
+ *
+ * \note That callback may be either blocking or non-blocking.
+ *
+ * \param ctx Context for the receive callback (typically a file
+ * descriptor)
+ * \param buf Buffer to write the received data to
+ * \param len Length of the receive buffer
+ *
+ * \returns If data has been received, the positive number of bytes received.
+ * \returns \c 0 if the connection has been closed.
+ * \returns If performing non-blocking I/O, \c MBEDTLS_ERR_SSL_WANT_READ
+ * must be returned when the operation would block.
+ * \returns Another negative error code on other kinds of failures.
+ *
+ * \note The callback may receive fewer bytes than the length of the
+ * buffer. It must always return the number of bytes actually
+ * received and written to the buffer.
+ */
+typedef int mbedtls_ssl_recv_t(void *ctx,
+ unsigned char *buf,
+ size_t len);
+
+/**
+ * \brief Callback type: receive data from the network, with timeout
+ *
+ * \note That callback must block until data is received, or the
+ * timeout delay expires, or the operation is interrupted by a
+ * signal.
+ *
+ * \param ctx Context for the receive callback (typically a file descriptor)
+ * \param buf Buffer to write the received data to
+ * \param len Length of the receive buffer
+ * \param timeout Maximum number of milliseconds to wait for data
+ * 0 means no timeout (potentially waiting forever)
+ *
+ * \return The callback must return the number of bytes received,
+ * or a non-zero error code:
+ * \c MBEDTLS_ERR_SSL_TIMEOUT if the operation timed out,
+ * \c MBEDTLS_ERR_SSL_WANT_READ if interrupted by a signal.
+ *
+ * \note The callback may receive fewer bytes than the length of the
+ * buffer. It must always return the number of bytes actually
+ * received and written to the buffer.
+ */
+typedef int mbedtls_ssl_recv_timeout_t(void *ctx,
+ unsigned char *buf,
+ size_t len,
+ uint32_t timeout);
+/**
+ * \brief Callback type: set a pair of timers/delays to watch
+ *
+ * \param ctx Context pointer
+ * \param int_ms Intermediate delay in milliseconds
+ * \param fin_ms Final delay in milliseconds
+ * 0 cancels the current timer.
+ *
+ * \note This callback must at least store the necessary information
+ * for the associated \c mbedtls_ssl_get_timer_t callback to
+ * return correct information.
+ *
+ * \note If using an event-driven style of programming, an event must
+ * be generated when the final delay is passed. The event must
+ * cause a call to \c mbedtls_ssl_handshake() with the proper
+ * SSL context to be scheduled. Care must be taken to ensure
+ * that at most one such call happens at a time.
+ *
+ * \note Only one timer at a time must be running. Calling this
+ * function while a timer is running must cancel it. Cancelled
+ * timers must not generate any event.
+ */
+typedef void mbedtls_ssl_set_timer_t(void *ctx,
+ uint32_t int_ms,
+ uint32_t fin_ms);
+
+/**
+ * \brief Callback type: get status of timers/delays
+ *
+ * \param ctx Context pointer
+ *
+ * \return This callback must return:
+ * -1 if cancelled (fin_ms == 0),
+ * 0 if none of the delays have passed,
+ * 1 if only the intermediate delay has passed,
+ * 2 if the final delay has passed.
+ */
+typedef int mbedtls_ssl_get_timer_t(void *ctx);
+
+/* Defined below */
+typedef struct mbedtls_ssl_session mbedtls_ssl_session;
+typedef struct mbedtls_ssl_context mbedtls_ssl_context;
+typedef struct mbedtls_ssl_config mbedtls_ssl_config;
+
+/* Defined in library/ssl_misc.h */
+typedef struct mbedtls_ssl_transform mbedtls_ssl_transform;
+typedef struct mbedtls_ssl_handshake_params mbedtls_ssl_handshake_params;
+typedef struct mbedtls_ssl_sig_hash_set_t mbedtls_ssl_sig_hash_set_t;
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+typedef struct mbedtls_ssl_key_cert mbedtls_ssl_key_cert;
+#endif
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+typedef struct mbedtls_ssl_flight_item mbedtls_ssl_flight_item;
+#endif
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
+#define MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_PSK_RESUMPTION \
+ MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK /* 1U << 0 */
+#define MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_PSK_EPHEMERAL_RESUMPTION \
+ MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL /* 1U << 2 */
+#define MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_EARLY_DATA (1U << 3)
+
+#define MBEDTLS_SSL_TLS1_3_TICKET_FLAGS_MASK \
+ (MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_PSK_RESUMPTION | \
+ MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_PSK_EPHEMERAL_RESUMPTION | \
+ MBEDTLS_SSL_TLS1_3_TICKET_ALLOW_EARLY_DATA)
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 && MBEDTLS_SSL_SESSION_TICKETS */
+
+/**
+ * \brief Callback type: server-side session cache getter
+ *
+ * The session cache is logically a key value store, with
+ * keys being session IDs and values being instances of
+ * mbedtls_ssl_session.
+ *
+ * This callback retrieves an entry in this key-value store.
+ *
+ * \param data The address of the session cache structure to query.
+ * \param session_id The buffer holding the session ID to query.
+ * \param session_id_len The length of \p session_id in Bytes.
+ * \param session The address of the session structure to populate.
+ * It is initialized with mbdtls_ssl_session_init(),
+ * and the callback must always leave it in a state
+ * where it can safely be freed via
+ * mbedtls_ssl_session_free() independent of the
+ * return code of this function.
+ *
+ * \return \c 0 on success
+ * \return A non-zero return value on failure.
+ *
+ */
+typedef int mbedtls_ssl_cache_get_t(void *data,
+ unsigned char const *session_id,
+ size_t session_id_len,
+ mbedtls_ssl_session *session);
+/**
+ * \brief Callback type: server-side session cache setter
+ *
+ * The session cache is logically a key value store, with
+ * keys being session IDs and values being instances of
+ * mbedtls_ssl_session.
+ *
+ * This callback sets an entry in this key-value store.
+ *
+ * \param data The address of the session cache structure to modify.
+ * \param session_id The buffer holding the session ID to query.
+ * \param session_id_len The length of \p session_id in Bytes.
+ * \param session The address of the session to be stored in the
+ * session cache.
+ *
+ * \return \c 0 on success
+ * \return A non-zero return value on failure.
+ */
+typedef int mbedtls_ssl_cache_set_t(void *data,
+ unsigned char const *session_id,
+ size_t session_id_len,
+ const mbedtls_ssl_session *session);
+
+#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+/**
+ * \brief Callback type: start external signature operation.
+ *
+ * This callback is called during an SSL handshake to start
+ * a signature decryption operation using an
+ * external processor. The parameter \p cert contains
+ * the public key; it is up to the callback function to
+ * determine how to access the associated private key.
+ *
+ * This function typically sends or enqueues a request, and
+ * does not wait for the operation to complete. This allows
+ * the handshake step to be non-blocking.
+ *
+ * The parameters \p ssl and \p cert are guaranteed to remain
+ * valid throughout the handshake. On the other hand, this
+ * function must save the contents of \p hash if the value
+ * is needed for later processing, because the \p hash buffer
+ * is no longer valid after this function returns.
+ *
+ * This function may call mbedtls_ssl_set_async_operation_data()
+ * to store an operation context for later retrieval
+ * by the resume or cancel callback.
+ *
+ * \note For RSA signatures, this function must produce output
+ * that is consistent with PKCS#1 v1.5 in the same way as
+ * mbedtls_rsa_pkcs1_sign(). Before the private key operation,
+ * apply the padding steps described in RFC 8017, section 9.2
+ * "EMSA-PKCS1-v1_5" as follows.
+ * - If \p md_alg is #MBEDTLS_MD_NONE, apply the PKCS#1 v1.5
+ * encoding, treating \p hash as the DigestInfo to be
+ * padded. In other words, apply EMSA-PKCS1-v1_5 starting
+ * from step 3, with `T = hash` and `tLen = hash_len`.
+ * - If `md_alg != MBEDTLS_MD_NONE`, apply the PKCS#1 v1.5
+ * encoding, treating \p hash as the hash to be encoded and
+ * padded. In other words, apply EMSA-PKCS1-v1_5 starting
+ * from step 2, with `digestAlgorithm` obtained by calling
+ * mbedtls_oid_get_oid_by_md() on \p md_alg.
+ *
+ * \note For ECDSA signatures, the output format is the DER encoding
+ * `Ecdsa-Sig-Value` defined in
+ * [RFC 4492 section 5.4](https://tools.ietf.org/html/rfc4492#section-5.4).
+ *
+ * \param ssl The SSL connection instance. It should not be
+ * modified other than via
+ * mbedtls_ssl_set_async_operation_data().
+ * \param cert Certificate containing the public key.
+ * In simple cases, this is one of the pointers passed to
+ * mbedtls_ssl_conf_own_cert() when configuring the SSL
+ * connection. However, if other callbacks are used, this
+ * property may not hold. For example, if an SNI callback
+ * is registered with mbedtls_ssl_conf_sni(), then
+ * this callback determines what certificate is used.
+ * \param md_alg Hash algorithm.
+ * \param hash Buffer containing the hash. This buffer is
+ * no longer valid when the function returns.
+ * \param hash_len Size of the \c hash buffer in bytes.
+ *
+ * \return 0 if the operation was started successfully and the SSL
+ * stack should call the resume callback immediately.
+ * \return #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if the operation
+ * was started successfully and the SSL stack should return
+ * immediately without calling the resume callback yet.
+ * \return #MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH if the external
+ * processor does not support this key. The SSL stack will
+ * use the private key object instead.
+ * \return Any other error indicates a fatal failure and is
+ * propagated up the call chain. The callback should
+ * use \c MBEDTLS_ERR_PK_xxx error codes, and <b>must not</b>
+ * use \c MBEDTLS_ERR_SSL_xxx error codes except as
+ * directed in the documentation of this callback.
+ */
+typedef int mbedtls_ssl_async_sign_t(mbedtls_ssl_context *ssl,
+ mbedtls_x509_crt *cert,
+ mbedtls_md_type_t md_alg,
+ const unsigned char *hash,
+ size_t hash_len);
+
+/**
+ * \brief Callback type: start external decryption operation.
+ *
+ * This callback is called during an SSL handshake to start
+ * an RSA decryption operation using an
+ * external processor. The parameter \p cert contains
+ * the public key; it is up to the callback function to
+ * determine how to access the associated private key.
+ *
+ * This function typically sends or enqueues a request, and
+ * does not wait for the operation to complete. This allows
+ * the handshake step to be non-blocking.
+ *
+ * The parameters \p ssl and \p cert are guaranteed to remain
+ * valid throughout the handshake. On the other hand, this
+ * function must save the contents of \p input if the value
+ * is needed for later processing, because the \p input buffer
+ * is no longer valid after this function returns.
+ *
+ * This function may call mbedtls_ssl_set_async_operation_data()
+ * to store an operation context for later retrieval
+ * by the resume or cancel callback.
+ *
+ * \warning RSA decryption as used in TLS is subject to a potential
+ * timing side channel attack first discovered by Bleichenbacher
+ * in 1998. This attack can be remotely exploitable
+ * in practice. To avoid this attack, you must ensure that
+ * if the callback performs an RSA decryption, the time it
+ * takes to execute and return the result does not depend
+ * on whether the RSA decryption succeeded or reported
+ * invalid padding.
+ *
+ * \param ssl The SSL connection instance. It should not be
+ * modified other than via
+ * mbedtls_ssl_set_async_operation_data().
+ * \param cert Certificate containing the public key.
+ * In simple cases, this is one of the pointers passed to
+ * mbedtls_ssl_conf_own_cert() when configuring the SSL
+ * connection. However, if other callbacks are used, this
+ * property may not hold. For example, if an SNI callback
+ * is registered with mbedtls_ssl_conf_sni(), then
+ * this callback determines what certificate is used.
+ * \param input Buffer containing the input ciphertext. This buffer
+ * is no longer valid when the function returns.
+ * \param input_len Size of the \p input buffer in bytes.
+ *
+ * \return 0 if the operation was started successfully and the SSL
+ * stack should call the resume callback immediately.
+ * \return #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if the operation
+ * was started successfully and the SSL stack should return
+ * immediately without calling the resume callback yet.
+ * \return #MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH if the external
+ * processor does not support this key. The SSL stack will
+ * use the private key object instead.
+ * \return Any other error indicates a fatal failure and is
+ * propagated up the call chain. The callback should
+ * use \c MBEDTLS_ERR_PK_xxx error codes, and <b>must not</b>
+ * use \c MBEDTLS_ERR_SSL_xxx error codes except as
+ * directed in the documentation of this callback.
+ */
+typedef int mbedtls_ssl_async_decrypt_t(mbedtls_ssl_context *ssl,
+ mbedtls_x509_crt *cert,
+ const unsigned char *input,
+ size_t input_len);
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+/**
+ * \brief Callback type: resume external operation.
+ *
+ * This callback is called during an SSL handshake to resume
+ * an external operation started by the
+ * ::mbedtls_ssl_async_sign_t or
+ * ::mbedtls_ssl_async_decrypt_t callback.
+ *
+ * This function typically checks the status of a pending
+ * request or causes the request queue to make progress, and
+ * does not wait for the operation to complete. This allows
+ * the handshake step to be non-blocking.
+ *
+ * This function may call mbedtls_ssl_get_async_operation_data()
+ * to retrieve an operation context set by the start callback.
+ * It may call mbedtls_ssl_set_async_operation_data() to modify
+ * this context.
+ *
+ * Note that when this function returns a status other than
+ * #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS, it must free any
+ * resources associated with the operation.
+ *
+ * \param ssl The SSL connection instance. It should not be
+ * modified other than via
+ * mbedtls_ssl_set_async_operation_data().
+ * \param output Buffer containing the output (signature or decrypted
+ * data) on success.
+ * \param output_len On success, number of bytes written to \p output.
+ * \param output_size Size of the \p output buffer in bytes.
+ *
+ * \return 0 if output of the operation is available in the
+ * \p output buffer.
+ * \return #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if the operation
+ * is still in progress. Subsequent requests for progress
+ * on the SSL connection will call the resume callback
+ * again.
+ * \return Any other error means that the operation is aborted.
+ * The SSL handshake is aborted. The callback should
+ * use \c MBEDTLS_ERR_PK_xxx error codes, and <b>must not</b>
+ * use \c MBEDTLS_ERR_SSL_xxx error codes except as
+ * directed in the documentation of this callback.
+ */
+typedef int mbedtls_ssl_async_resume_t(mbedtls_ssl_context *ssl,
+ unsigned char *output,
+ size_t *output_len,
+ size_t output_size);
+
+/**
+ * \brief Callback type: cancel external operation.
+ *
+ * This callback is called if an SSL connection is closed
+ * while an asynchronous operation is in progress. Note that
+ * this callback is not called if the
+ * ::mbedtls_ssl_async_resume_t callback has run and has
+ * returned a value other than
+ * #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS, since in that case
+ * the asynchronous operation has already completed.
+ *
+ * This function may call mbedtls_ssl_get_async_operation_data()
+ * to retrieve an operation context set by the start callback.
+ *
+ * \param ssl The SSL connection instance. It should not be
+ * modified.
+ */
+typedef void mbedtls_ssl_async_cancel_t(mbedtls_ssl_context *ssl);
+#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
+
+#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED) && \
+ !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_MAX_LEN 48
+#if defined(MBEDTLS_MD_CAN_SHA256)
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE MBEDTLS_MD_SHA256
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN 32
+#elif defined(MBEDTLS_MD_CAN_SHA384)
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE MBEDTLS_MD_SHA384
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN 48
+#elif defined(MBEDTLS_MD_CAN_SHA1)
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_TYPE MBEDTLS_MD_SHA1
+#define MBEDTLS_SSL_PEER_CERT_DIGEST_DFL_LEN 20
+#else
+/* This is already checked in check_config.h, but be sure. */
+#error "Bad configuration - need SHA-1, SHA-256 or SHA-512 enabled to compute digest of peer CRT."
+#endif
+#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED &&
+ !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+
+typedef struct {
+ unsigned char client_application_traffic_secret_N[MBEDTLS_TLS1_3_MD_MAX_SIZE];
+ unsigned char server_application_traffic_secret_N[MBEDTLS_TLS1_3_MD_MAX_SIZE];
+ unsigned char exporter_master_secret[MBEDTLS_TLS1_3_MD_MAX_SIZE];
+ unsigned char resumption_master_secret[MBEDTLS_TLS1_3_MD_MAX_SIZE];
+} mbedtls_ssl_tls13_application_secrets;
+
+#if defined(MBEDTLS_SSL_DTLS_SRTP)
+
+#define MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH 255
+#define MBEDTLS_TLS_SRTP_MAX_PROFILE_LIST_LENGTH 4
+/*
+ * For code readability use a typedef for DTLS-SRTP profiles
+ *
+ * Use_srtp extension protection profiles values as defined in
+ * http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml
+ *
+ * Reminder: if this list is expanded mbedtls_ssl_check_srtp_profile_value
+ * must be updated too.
+ */
+#define MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_80 ((uint16_t) 0x0001)
+#define MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_32 ((uint16_t) 0x0002)
+#define MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_80 ((uint16_t) 0x0005)
+#define MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_32 ((uint16_t) 0x0006)
+/* This one is not iana defined, but for code readability. */
+#define MBEDTLS_TLS_SRTP_UNSET ((uint16_t) 0x0000)
+
+typedef uint16_t mbedtls_ssl_srtp_profile;
+
+typedef struct mbedtls_dtls_srtp_info_t {
+ /*! The SRTP profile that was negotiated. */
+ mbedtls_ssl_srtp_profile MBEDTLS_PRIVATE(chosen_dtls_srtp_profile);
+ /*! The length of mki_value. */
+ uint16_t MBEDTLS_PRIVATE(mki_len);
+ /*! The mki_value used, with max size of 256 bytes. */
+ unsigned char MBEDTLS_PRIVATE(mki_value)[MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH];
+}
+mbedtls_dtls_srtp_info;
+
+#endif /* MBEDTLS_SSL_DTLS_SRTP */
+
+/** Human-friendly representation of the (D)TLS protocol version. */
+typedef enum {
+ MBEDTLS_SSL_VERSION_UNKNOWN, /*!< Context not in use or version not yet negotiated. */
+ MBEDTLS_SSL_VERSION_TLS1_2 = 0x0303, /*!< (D)TLS 1.2 */
+ MBEDTLS_SSL_VERSION_TLS1_3 = 0x0304, /*!< (D)TLS 1.3 */
+} mbedtls_ssl_protocol_version;
+
+/*
+ * This structure is used for storing current session data.
+ *
+ * Note: when changing this definition, we need to check and update:
+ * - in tests/suites/test_suite_ssl.function:
+ * ssl_populate_session() and ssl_serialize_session_save_load()
+ * - in library/ssl_tls.c:
+ * mbedtls_ssl_session_init() and mbedtls_ssl_session_free()
+ * mbedtls_ssl_session_save() and ssl_session_load()
+ * ssl_session_copy()
+ */
+struct mbedtls_ssl_session {
+#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
+ unsigned char MBEDTLS_PRIVATE(mfl_code); /*!< MaxFragmentLength negotiated by peer */
+#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
+
+ unsigned char MBEDTLS_PRIVATE(exported);
+
+ /** TLS version negotiated in the session. Used if and when renegotiating
+ * or resuming a session instead of the configured minor TLS version.
+ */
+ mbedtls_ssl_protocol_version MBEDTLS_PRIVATE(tls_version);
+
+#if defined(MBEDTLS_HAVE_TIME)
+ mbedtls_time_t MBEDTLS_PRIVATE(start); /*!< starting time */
+#endif
+ int MBEDTLS_PRIVATE(ciphersuite); /*!< chosen ciphersuite */
+ size_t MBEDTLS_PRIVATE(id_len); /*!< session id length */
+ unsigned char MBEDTLS_PRIVATE(id)[32]; /*!< session identifier */
+ unsigned char MBEDTLS_PRIVATE(master)[48]; /*!< the master secret */
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
+ mbedtls_x509_crt *MBEDTLS_PRIVATE(peer_cert); /*!< peer X.509 cert chain */
+#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+ /*! The digest of the peer's end-CRT. This must be kept to detect CRT
+ * changes during renegotiation, mitigating the triple handshake attack. */
+ unsigned char *MBEDTLS_PRIVATE(peer_cert_digest);
+ size_t MBEDTLS_PRIVATE(peer_cert_digest_len);
+ mbedtls_md_type_t MBEDTLS_PRIVATE(peer_cert_digest_type);
+#endif /* !MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+ uint32_t MBEDTLS_PRIVATE(verify_result); /*!< verification result */
+
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
+ unsigned char *MBEDTLS_PRIVATE(ticket); /*!< RFC 5077 session ticket */
+ size_t MBEDTLS_PRIVATE(ticket_len); /*!< session ticket length */
+ uint32_t MBEDTLS_PRIVATE(ticket_lifetime); /*!< ticket lifetime hint */
+#endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_CLI_C */
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
+ uint8_t MBEDTLS_PRIVATE(endpoint); /*!< 0: client, 1: server */
+ uint8_t MBEDTLS_PRIVATE(ticket_flags); /*!< Ticket flags */
+ uint32_t MBEDTLS_PRIVATE(ticket_age_add); /*!< Randomly generated value used to obscure the age of the ticket */
+ uint8_t MBEDTLS_PRIVATE(resumption_key_len); /*!< resumption_key length */
+ unsigned char MBEDTLS_PRIVATE(resumption_key)[MBEDTLS_SSL_TLS1_3_TICKET_RESUMPTION_KEY_LEN];
+
+#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION) && defined(MBEDTLS_SSL_CLI_C)
+ char *MBEDTLS_PRIVATE(hostname); /*!< host name binded with tickets */
+#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION && MBEDTLS_SSL_CLI_C */
+
+#if defined(MBEDTLS_HAVE_TIME) && defined(MBEDTLS_SSL_CLI_C)
+ mbedtls_time_t MBEDTLS_PRIVATE(ticket_received); /*!< time ticket was received */
+#endif /* MBEDTLS_HAVE_TIME && MBEDTLS_SSL_CLI_C */
+
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 && MBEDTLS_SSL_SESSION_TICKETS */
+
+#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
+ int MBEDTLS_PRIVATE(encrypt_then_mac); /*!< flag for EtM activation */
+#endif
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+ mbedtls_ssl_tls13_application_secrets MBEDTLS_PRIVATE(app_secrets);
+#endif
+};
+
+/*
+ * Identifiers for PRFs used in various versions of TLS.
+ */
+typedef enum {
+ MBEDTLS_SSL_TLS_PRF_NONE,
+ MBEDTLS_SSL_TLS_PRF_SHA384,
+ MBEDTLS_SSL_TLS_PRF_SHA256,
+ MBEDTLS_SSL_HKDF_EXPAND_SHA384,
+ MBEDTLS_SSL_HKDF_EXPAND_SHA256
+}
+mbedtls_tls_prf_types;
+
+typedef enum {
+ MBEDTLS_SSL_KEY_EXPORT_TLS12_MASTER_SECRET = 0,
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+ MBEDTLS_SSL_KEY_EXPORT_TLS1_3_CLIENT_EARLY_SECRET,
+ MBEDTLS_SSL_KEY_EXPORT_TLS1_3_EARLY_EXPORTER_SECRET,
+ MBEDTLS_SSL_KEY_EXPORT_TLS1_3_CLIENT_HANDSHAKE_TRAFFIC_SECRET,
+ MBEDTLS_SSL_KEY_EXPORT_TLS1_3_SERVER_HANDSHAKE_TRAFFIC_SECRET,
+ MBEDTLS_SSL_KEY_EXPORT_TLS1_3_CLIENT_APPLICATION_TRAFFIC_SECRET,
+ MBEDTLS_SSL_KEY_EXPORT_TLS1_3_SERVER_APPLICATION_TRAFFIC_SECRET,
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
+} mbedtls_ssl_key_export_type;
+
+/**
+ * \brief Callback type: Export key alongside random values for
+ * session identification, and PRF for
+ * implementation of TLS key exporters.
+ *
+ * \param p_expkey Context for the callback.
+ * \param type The type of the key that is being exported.
+ * \param secret The address of the buffer holding the secret
+ * that's being exporterd.
+ * \param secret_len The length of \p secret in bytes.
+ * \param client_random The client random bytes.
+ * \param server_random The server random bytes.
+ * \param tls_prf_type The identifier for the PRF used in the handshake
+ * to which the key belongs.
+ */
+typedef void mbedtls_ssl_export_keys_t(void *p_expkey,
+ mbedtls_ssl_key_export_type type,
+ const unsigned char *secret,
+ size_t secret_len,
+ const unsigned char client_random[32],
+ const unsigned char server_random[32],
+ mbedtls_tls_prf_types tls_prf_type);
+
+#if defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Callback type: generic handshake callback
+ *
+ * \note Callbacks may use user_data funcs to set/get app user data.
+ * See \c mbedtls_ssl_get_user_data_p()
+ * \c mbedtls_ssl_get_user_data_n()
+ * \c mbedtls_ssl_conf_get_user_data_p()
+ * \c mbedtls_ssl_conf_get_user_data_n()
+ *
+ * \param ssl \c mbedtls_ssl_context on which the callback is run
+ *
+ * \return The return value of the callback is 0 if successful,
+ * or a specific MBEDTLS_ERR_XXX code, which will cause
+ * the handshake to be aborted.
+ */
+typedef int (*mbedtls_ssl_hs_cb_t)(mbedtls_ssl_context *ssl);
+#endif
+
+/* A type for storing user data in a library structure.
+ *
+ * The representation of type may change in future versions of the library.
+ * Only the behaviors guaranteed by documented accessor functions are
+ * guaranteed to remain stable.
+ */
+typedef union {
+ uintptr_t n; /* typically a handle to an associated object */
+ void *p; /* typically a pointer to extra data */
+} mbedtls_ssl_user_data_t;
+
+/**
+ * SSL/TLS configuration to be shared between mbedtls_ssl_context structures.
+ */
+struct mbedtls_ssl_config {
+ /* Group items mostly by size. This helps to reduce memory wasted to
+ * padding. It also helps to keep smaller fields early in the structure,
+ * so that elements tend to be in the 128-element direct access window
+ * on Arm Thumb, which reduces the code size. */
+
+ mbedtls_ssl_protocol_version MBEDTLS_PRIVATE(max_tls_version); /*!< max. TLS version used */
+ mbedtls_ssl_protocol_version MBEDTLS_PRIVATE(min_tls_version); /*!< min. TLS version used */
+
+ /*
+ * Flags (could be bit-fields to save RAM, but separate bytes make
+ * the code smaller on architectures with an instruction for direct
+ * byte access).
+ */
+
+ uint8_t MBEDTLS_PRIVATE(endpoint); /*!< 0: client, 1: server */
+ uint8_t MBEDTLS_PRIVATE(transport); /*!< 0: stream (TLS), 1: datagram (DTLS) */
+ uint8_t MBEDTLS_PRIVATE(authmode); /*!< MBEDTLS_SSL_VERIFY_XXX */
+ /* needed even with renego disabled for LEGACY_BREAK_HANDSHAKE */
+ uint8_t MBEDTLS_PRIVATE(allow_legacy_renegotiation); /*!< MBEDTLS_LEGACY_XXX */
+#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
+ uint8_t MBEDTLS_PRIVATE(mfl_code); /*!< desired fragment length indicator
+ (MBEDTLS_SSL_MAX_FRAG_LEN_XXX) */
+#endif
+#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
+ uint8_t MBEDTLS_PRIVATE(encrypt_then_mac); /*!< negotiate encrypt-then-mac? */
+#endif
+#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
+ uint8_t MBEDTLS_PRIVATE(extended_ms); /*!< negotiate extended master secret? */
+#endif
+#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
+ uint8_t MBEDTLS_PRIVATE(anti_replay); /*!< detect and prevent replay? */
+#endif
+#if defined(MBEDTLS_SSL_RENEGOTIATION)
+ uint8_t MBEDTLS_PRIVATE(disable_renegotiation); /*!< disable renegotiation? */
+#endif
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
+ defined(MBEDTLS_SSL_CLI_C)
+ uint8_t MBEDTLS_PRIVATE(session_tickets); /*!< use session tickets? */
+#endif
+
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
+ defined(MBEDTLS_SSL_SRV_C) && \
+ defined(MBEDTLS_SSL_PROTO_TLS1_3)
+ uint16_t MBEDTLS_PRIVATE(new_session_tickets_count); /*!< number of NewSessionTicket */
+#endif
+
+#if defined(MBEDTLS_SSL_SRV_C)
+ uint8_t MBEDTLS_PRIVATE(cert_req_ca_list); /*!< enable sending CA list in
+ Certificate Request messages? */
+ uint8_t MBEDTLS_PRIVATE(respect_cli_pref); /*!< pick the ciphersuite according to
+ the client's preferences rather
+ than ours? */
+#endif
+#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
+ uint8_t MBEDTLS_PRIVATE(ignore_unexpected_cid); /*!< Should DTLS record with
+ * unexpected CID
+ * lead to failure? */
+#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
+#if defined(MBEDTLS_SSL_DTLS_SRTP)
+ uint8_t MBEDTLS_PRIVATE(dtls_srtp_mki_support); /* support having mki_value
+ in the use_srtp extension? */
+#endif
+
+ /*
+ * Pointers
+ */
+
+ /** Allowed ciphersuites for (D)TLS 1.2 (0-terminated) */
+ const int *MBEDTLS_PRIVATE(ciphersuite_list);
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+ /** Allowed TLS 1.3 key exchange modes. */
+ int MBEDTLS_PRIVATE(tls13_kex_modes);
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
+
+ /** Callback for printing debug output */
+ void(*MBEDTLS_PRIVATE(f_dbg))(void *, int, const char *, int, const char *);
+ void *MBEDTLS_PRIVATE(p_dbg); /*!< context for the debug function */
+
+ /** Callback for getting (pseudo-)random numbers */
+ int(*MBEDTLS_PRIVATE(f_rng))(void *, unsigned char *, size_t);
+ void *MBEDTLS_PRIVATE(p_rng); /*!< context for the RNG function */
+
+ /** Callback to retrieve a session from the cache */
+ mbedtls_ssl_cache_get_t *MBEDTLS_PRIVATE(f_get_cache);
+ /** Callback to store a session into the cache */
+ mbedtls_ssl_cache_set_t *MBEDTLS_PRIVATE(f_set_cache);
+ void *MBEDTLS_PRIVATE(p_cache); /*!< context for cache callbacks */
+
+#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
+ /** Callback for setting cert according to SNI extension */
+ int(*MBEDTLS_PRIVATE(f_sni))(void *, mbedtls_ssl_context *, const unsigned char *, size_t);
+ void *MBEDTLS_PRIVATE(p_sni); /*!< context for SNI callback */
+#endif
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+ /** Callback to customize X.509 certificate chain verification */
+ int(*MBEDTLS_PRIVATE(f_vrfy))(void *, mbedtls_x509_crt *, int, uint32_t *);
+ void *MBEDTLS_PRIVATE(p_vrfy); /*!< context for X.509 verify calllback */
+#endif
+
+#if defined(MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED)
+#if defined(MBEDTLS_SSL_SRV_C)
+ /** Callback to retrieve PSK key from identity */
+ int(*MBEDTLS_PRIVATE(f_psk))(void *, mbedtls_ssl_context *, const unsigned char *, size_t);
+ void *MBEDTLS_PRIVATE(p_psk); /*!< context for PSK callback */
+#endif
+#endif
+
+#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
+ /** Callback to create & write a cookie for ClientHello verification */
+ int(*MBEDTLS_PRIVATE(f_cookie_write))(void *, unsigned char **, unsigned char *,
+ const unsigned char *, size_t);
+ /** Callback to verify validity of a ClientHello cookie */
+ int(*MBEDTLS_PRIVATE(f_cookie_check))(void *, const unsigned char *, size_t,
+ const unsigned char *, size_t);
+ void *MBEDTLS_PRIVATE(p_cookie); /*!< context for the cookie callbacks */
+#endif
+
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_SRV_C)
+ /** Callback to create & write a session ticket */
+ int(*MBEDTLS_PRIVATE(f_ticket_write))(void *, const mbedtls_ssl_session *,
+ unsigned char *, const unsigned char *, size_t *,
+ uint32_t *);
+ /** Callback to parse a session ticket into a session structure */
+ int(*MBEDTLS_PRIVATE(f_ticket_parse))(void *, mbedtls_ssl_session *, unsigned char *, size_t);
+ void *MBEDTLS_PRIVATE(p_ticket); /*!< context for the ticket callbacks */
+#endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_SRV_C */
+#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
+ size_t MBEDTLS_PRIVATE(cid_len); /*!< The length of CIDs for incoming DTLS records. */
+#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+ const mbedtls_x509_crt_profile *MBEDTLS_PRIVATE(cert_profile); /*!< verification profile */
+ mbedtls_ssl_key_cert *MBEDTLS_PRIVATE(key_cert); /*!< own certificate/key pair(s) */
+ mbedtls_x509_crt *MBEDTLS_PRIVATE(ca_chain); /*!< trusted CAs */
+ mbedtls_x509_crl *MBEDTLS_PRIVATE(ca_crl); /*!< trusted CAs CRLs */
+#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
+ mbedtls_x509_crt_ca_cb_t MBEDTLS_PRIVATE(f_ca_cb);
+ void *MBEDTLS_PRIVATE(p_ca_cb);
+#endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+ mbedtls_ssl_async_sign_t *MBEDTLS_PRIVATE(f_async_sign_start); /*!< start asynchronous signature operation */
+ mbedtls_ssl_async_decrypt_t *MBEDTLS_PRIVATE(f_async_decrypt_start); /*!< start asynchronous decryption operation */
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+ mbedtls_ssl_async_resume_t *MBEDTLS_PRIVATE(f_async_resume); /*!< resume asynchronous operation */
+ mbedtls_ssl_async_cancel_t *MBEDTLS_PRIVATE(f_async_cancel); /*!< cancel asynchronous operation */
+ void *MBEDTLS_PRIVATE(p_async_config_data); /*!< Configuration data set by mbedtls_ssl_conf_async_private_cb(). */
+#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
+
+#if defined(MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED)
+
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+ const int *MBEDTLS_PRIVATE(sig_hashes); /*!< allowed signature hashes */
+#endif
+ const uint16_t *MBEDTLS_PRIVATE(sig_algs); /*!< allowed signature algorithms */
+#endif /* MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED */
+
+#if defined(MBEDTLS_ECP_C) && !defined(MBEDTLS_DEPRECATED_REMOVED)
+ const mbedtls_ecp_group_id *MBEDTLS_PRIVATE(curve_list); /*!< allowed curves */
+#endif
+
+ const uint16_t *MBEDTLS_PRIVATE(group_list); /*!< allowed IANA NamedGroups */
+
+#if defined(MBEDTLS_DHM_C)
+ mbedtls_mpi MBEDTLS_PRIVATE(dhm_P); /*!< prime modulus for DHM */
+ mbedtls_mpi MBEDTLS_PRIVATE(dhm_G); /*!< generator for DHM */
+#endif
+
+#if defined(MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED)
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+ mbedtls_svc_key_id_t MBEDTLS_PRIVATE(psk_opaque); /*!< PSA key slot holding opaque PSK. This field
+ * should only be set via
+ * mbedtls_ssl_conf_psk_opaque().
+ * If either no PSK or a raw PSK have been
+ * configured, this has value \c 0.
+ */
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+ unsigned char *MBEDTLS_PRIVATE(psk); /*!< The raw pre-shared key. This field should
+ * only be set via mbedtls_ssl_conf_psk().
+ * If either no PSK or an opaque PSK
+ * have been configured, this has value NULL. */
+ size_t MBEDTLS_PRIVATE(psk_len); /*!< The length of the raw pre-shared key.
+ * This field should only be set via
+ * mbedtls_ssl_conf_psk().
+ * Its value is non-zero if and only if
+ * \c psk is not \c NULL. */
+
+ unsigned char *MBEDTLS_PRIVATE(psk_identity); /*!< The PSK identity for PSK negotiation.
+ * This field should only be set via
+ * mbedtls_ssl_conf_psk().
+ * This is set if and only if either
+ * \c psk or \c psk_opaque are set. */
+ size_t MBEDTLS_PRIVATE(psk_identity_len);/*!< The length of PSK identity.
+ * This field should only be set via
+ * mbedtls_ssl_conf_psk().
+ * Its value is non-zero if and only if
+ * \c psk is not \c NULL or \c psk_opaque
+ * is not \c 0. */
+#endif /* MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED */
+
+#if defined(MBEDTLS_SSL_EARLY_DATA)
+ int MBEDTLS_PRIVATE(early_data_enabled); /*!< Early data enablement:
+ * - MBEDTLS_SSL_EARLY_DATA_DISABLED,
+ * - MBEDTLS_SSL_EARLY_DATA_ENABLED */
+
+#if defined(MBEDTLS_SSL_SRV_C)
+ /* The maximum amount of 0-RTT data. RFC 8446 section 4.6.1 */
+ uint32_t MBEDTLS_PRIVATE(max_early_data_size);
+#endif /* MBEDTLS_SSL_SRV_C */
+
+#endif /* MBEDTLS_SSL_EARLY_DATA */
+
+#if defined(MBEDTLS_SSL_ALPN)
+ const char **MBEDTLS_PRIVATE(alpn_list); /*!< ordered list of protocols */
+#endif
+
+#if defined(MBEDTLS_SSL_DTLS_SRTP)
+ /*! ordered list of supported srtp profile */
+ const mbedtls_ssl_srtp_profile *MBEDTLS_PRIVATE(dtls_srtp_profile_list);
+ /*! number of supported profiles */
+ size_t MBEDTLS_PRIVATE(dtls_srtp_profile_list_len);
+#endif /* MBEDTLS_SSL_DTLS_SRTP */
+
+ /*
+ * Numerical settings (int)
+ */
+
+ uint32_t MBEDTLS_PRIVATE(read_timeout); /*!< timeout for mbedtls_ssl_read (ms) */
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+ uint32_t MBEDTLS_PRIVATE(hs_timeout_min); /*!< initial value of the handshake
+ retransmission timeout (ms) */
+ uint32_t MBEDTLS_PRIVATE(hs_timeout_max); /*!< maximum value of the handshake
+ retransmission timeout (ms) */
+#endif
+
+#if defined(MBEDTLS_SSL_RENEGOTIATION)
+ int MBEDTLS_PRIVATE(renego_max_records); /*!< grace period for renegotiation */
+ unsigned char MBEDTLS_PRIVATE(renego_period)[8]; /*!< value of the record counters
+ that triggers renegotiation */
+#endif
+
+ unsigned int MBEDTLS_PRIVATE(badmac_limit); /*!< limit of records with a bad MAC */
+
+#if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
+ unsigned int MBEDTLS_PRIVATE(dhm_min_bitlen); /*!< min. bit length of the DHM prime */
+#endif
+
+ /** User data pointer or handle.
+ *
+ * The library sets this to \p 0 when creating a context and does not
+ * access it afterwards.
+ */
+ mbedtls_ssl_user_data_t MBEDTLS_PRIVATE(user_data);
+
+#if defined(MBEDTLS_SSL_SRV_C)
+ mbedtls_ssl_hs_cb_t MBEDTLS_PRIVATE(f_cert_cb); /*!< certificate selection callback */
+#endif /* MBEDTLS_SSL_SRV_C */
+
+#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+ const mbedtls_x509_crt *MBEDTLS_PRIVATE(dn_hints);/*!< acceptable client cert issuers */
+#endif
+};
+
+struct mbedtls_ssl_context {
+ const mbedtls_ssl_config *MBEDTLS_PRIVATE(conf); /*!< configuration information */
+
+ /*
+ * Miscellaneous
+ */
+ int MBEDTLS_PRIVATE(state); /*!< SSL handshake: current state */
+#if defined(MBEDTLS_SSL_RENEGOTIATION)
+ int MBEDTLS_PRIVATE(renego_status); /*!< Initial, in progress, pending? */
+ int MBEDTLS_PRIVATE(renego_records_seen); /*!< Records since renego request, or with DTLS,
+ number of retransmissions of request if
+ renego_max_records is < 0 */
+#endif /* MBEDTLS_SSL_RENEGOTIATION */
+
+ /**
+ * Maximum TLS version to be negotiated, then negotiated TLS version.
+ *
+ * It is initialized as the configured maximum TLS version to be
+ * negotiated by mbedtls_ssl_setup().
+ *
+ * When renegotiating or resuming a session, it is overwritten in the
+ * ClientHello writing preparation stage with the previously negotiated
+ * TLS version.
+ *
+ * On client side, it is updated to the TLS version selected by the server
+ * for the handshake when the ServerHello is received.
+ *
+ * On server side, it is updated to the TLS version the server selects for
+ * the handshake when the ClientHello is received.
+ */
+ mbedtls_ssl_protocol_version MBEDTLS_PRIVATE(tls_version);
+
+ unsigned MBEDTLS_PRIVATE(badmac_seen); /*!< records with a bad MAC received */
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+ /** Callback to customize X.509 certificate chain verification */
+ int(*MBEDTLS_PRIVATE(f_vrfy))(void *, mbedtls_x509_crt *, int, uint32_t *);
+ void *MBEDTLS_PRIVATE(p_vrfy); /*!< context for X.509 verify callback */
+#endif
+
+ mbedtls_ssl_send_t *MBEDTLS_PRIVATE(f_send); /*!< Callback for network send */
+ mbedtls_ssl_recv_t *MBEDTLS_PRIVATE(f_recv); /*!< Callback for network receive */
+ mbedtls_ssl_recv_timeout_t *MBEDTLS_PRIVATE(f_recv_timeout);
+ /*!< Callback for network receive with timeout */
+
+ void *MBEDTLS_PRIVATE(p_bio); /*!< context for I/O operations */
+
+ /*
+ * Session layer
+ */
+ mbedtls_ssl_session *MBEDTLS_PRIVATE(session_in); /*!< current session data (in) */
+ mbedtls_ssl_session *MBEDTLS_PRIVATE(session_out); /*!< current session data (out) */
+ mbedtls_ssl_session *MBEDTLS_PRIVATE(session); /*!< negotiated session data */
+ mbedtls_ssl_session *MBEDTLS_PRIVATE(session_negotiate); /*!< session data in negotiation */
+
+ mbedtls_ssl_handshake_params *MBEDTLS_PRIVATE(handshake); /*!< params required only during
+ the handshake process */
+
+ /*
+ * Record layer transformations
+ */
+ mbedtls_ssl_transform *MBEDTLS_PRIVATE(transform_in); /*!< current transform params (in)
+ * This is always a reference,
+ * never an owning pointer. */
+ mbedtls_ssl_transform *MBEDTLS_PRIVATE(transform_out); /*!< current transform params (out)
+ * This is always a reference,
+ * never an owning pointer. */
+ mbedtls_ssl_transform *MBEDTLS_PRIVATE(transform); /*!< negotiated transform params
+ * This pointer owns the transform
+ * it references. */
+#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
+ mbedtls_ssl_transform *MBEDTLS_PRIVATE(transform_negotiate); /*!< transform params in negotiation
+ * This pointer owns the transform
+ * it references. */
+#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+ /*! The application data transform in TLS 1.3.
+ * This pointer owns the transform it references. */
+ mbedtls_ssl_transform *MBEDTLS_PRIVATE(transform_application);
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
+
+ /*
+ * Timers
+ */
+ void *MBEDTLS_PRIVATE(p_timer); /*!< context for the timer callbacks */
+
+ mbedtls_ssl_set_timer_t *MBEDTLS_PRIVATE(f_set_timer); /*!< set timer callback */
+ mbedtls_ssl_get_timer_t *MBEDTLS_PRIVATE(f_get_timer); /*!< get timer callback */
+
+ /*
+ * Record layer (incoming data)
+ */
+ unsigned char *MBEDTLS_PRIVATE(in_buf); /*!< input buffer */
+ unsigned char *MBEDTLS_PRIVATE(in_ctr); /*!< 64-bit incoming message counter
+ TLS: maintained by us
+ DTLS: read from peer */
+ unsigned char *MBEDTLS_PRIVATE(in_hdr); /*!< start of record header */
+#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
+ unsigned char *MBEDTLS_PRIVATE(in_cid); /*!< The start of the CID;
+ * (the end is marked by in_len). */
+#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
+ unsigned char *MBEDTLS_PRIVATE(in_len); /*!< two-bytes message length field */
+ unsigned char *MBEDTLS_PRIVATE(in_iv); /*!< ivlen-byte IV */
+ unsigned char *MBEDTLS_PRIVATE(in_msg); /*!< message contents (in_iv+ivlen) */
+ unsigned char *MBEDTLS_PRIVATE(in_offt); /*!< read offset in application data */
+
+ int MBEDTLS_PRIVATE(in_msgtype); /*!< record header: message type */
+ size_t MBEDTLS_PRIVATE(in_msglen); /*!< record header: message length */
+ size_t MBEDTLS_PRIVATE(in_left); /*!< amount of data read so far */
+#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
+ size_t MBEDTLS_PRIVATE(in_buf_len); /*!< length of input buffer */
+#endif
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+ uint16_t MBEDTLS_PRIVATE(in_epoch); /*!< DTLS epoch for incoming records */
+ size_t MBEDTLS_PRIVATE(next_record_offset); /*!< offset of the next record in datagram
+ (equal to in_left if none) */
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
+ uint64_t MBEDTLS_PRIVATE(in_window_top); /*!< last validated record seq_num */
+ uint64_t MBEDTLS_PRIVATE(in_window); /*!< bitmask for replay detection */
+#endif /* MBEDTLS_SSL_DTLS_ANTI_REPLAY */
+
+ size_t MBEDTLS_PRIVATE(in_hslen); /*!< current handshake message length,
+ including the handshake header */
+ int MBEDTLS_PRIVATE(nb_zero); /*!< # of 0-length encrypted messages */
+
+ int MBEDTLS_PRIVATE(keep_current_message); /*!< drop or reuse current message
+ on next call to record layer? */
+
+ /* The following three variables indicate if and, if yes,
+ * what kind of alert is pending to be sent.
+ */
+ unsigned char MBEDTLS_PRIVATE(send_alert); /*!< Determines if a fatal alert
+ should be sent. Values:
+ - \c 0 , no alert is to be sent.
+ - \c 1 , alert is to be sent. */
+ unsigned char MBEDTLS_PRIVATE(alert_type); /*!< Type of alert if send_alert
+ != 0 */
+ int MBEDTLS_PRIVATE(alert_reason); /*!< The error code to be returned
+ to the user once the fatal alert
+ has been sent. */
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+ uint8_t MBEDTLS_PRIVATE(disable_datagram_packing); /*!< Disable packing multiple records
+ * within a single datagram. */
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+ /*
+ * Record layer (outgoing data)
+ */
+ unsigned char *MBEDTLS_PRIVATE(out_buf); /*!< output buffer */
+ unsigned char *MBEDTLS_PRIVATE(out_ctr); /*!< 64-bit outgoing message counter */
+ unsigned char *MBEDTLS_PRIVATE(out_hdr); /*!< start of record header */
+#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
+ unsigned char *MBEDTLS_PRIVATE(out_cid); /*!< The start of the CID;
+ * (the end is marked by in_len). */
+#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
+ unsigned char *MBEDTLS_PRIVATE(out_len); /*!< two-bytes message length field */
+ unsigned char *MBEDTLS_PRIVATE(out_iv); /*!< ivlen-byte IV */
+ unsigned char *MBEDTLS_PRIVATE(out_msg); /*!< message contents (out_iv+ivlen) */
+
+ int MBEDTLS_PRIVATE(out_msgtype); /*!< record header: message type */
+ size_t MBEDTLS_PRIVATE(out_msglen); /*!< record header: message length */
+ size_t MBEDTLS_PRIVATE(out_left); /*!< amount of data not yet written */
+#if defined(MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH)
+ size_t MBEDTLS_PRIVATE(out_buf_len); /*!< length of output buffer */
+#endif
+
+ unsigned char MBEDTLS_PRIVATE(cur_out_ctr)[MBEDTLS_SSL_SEQUENCE_NUMBER_LEN]; /*!< Outgoing record sequence number. */
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+ uint16_t MBEDTLS_PRIVATE(mtu); /*!< path mtu, used to fragment outgoing messages */
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+ /*
+ * User settings
+ */
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+ char *MBEDTLS_PRIVATE(hostname); /*!< expected peer CN for verification
+ (and SNI if available) */
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+#if defined(MBEDTLS_SSL_ALPN)
+ const char *MBEDTLS_PRIVATE(alpn_chosen); /*!< negotiated protocol */
+#endif /* MBEDTLS_SSL_ALPN */
+
+#if defined(MBEDTLS_SSL_DTLS_SRTP)
+ /*
+ * use_srtp extension
+ */
+ mbedtls_dtls_srtp_info MBEDTLS_PRIVATE(dtls_srtp_info);
+#endif /* MBEDTLS_SSL_DTLS_SRTP */
+
+ /*
+ * Information for DTLS hello verify
+ */
+#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
+ unsigned char *MBEDTLS_PRIVATE(cli_id); /*!< transport-level ID of the client */
+ size_t MBEDTLS_PRIVATE(cli_id_len); /*!< length of cli_id */
+#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY && MBEDTLS_SSL_SRV_C */
+
+ /*
+ * Secure renegotiation
+ */
+ /* needed to know when to send extension on server */
+ int MBEDTLS_PRIVATE(secure_renegotiation); /*!< does peer support legacy or
+ secure renegotiation */
+#if defined(MBEDTLS_SSL_RENEGOTIATION)
+ size_t MBEDTLS_PRIVATE(verify_data_len); /*!< length of verify data stored */
+ char MBEDTLS_PRIVATE(own_verify_data)[MBEDTLS_SSL_VERIFY_DATA_MAX_LEN]; /*!< previous handshake verify data */
+ char MBEDTLS_PRIVATE(peer_verify_data)[MBEDTLS_SSL_VERIFY_DATA_MAX_LEN]; /*!< previous handshake verify data */
+#endif /* MBEDTLS_SSL_RENEGOTIATION */
+
+#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
+ /* CID configuration to use in subsequent handshakes. */
+
+ /*! The next incoming CID, chosen by the user and applying to
+ * all subsequent handshakes. This may be different from the
+ * CID currently used in case the user has re-configured the CID
+ * after an initial handshake. */
+ unsigned char MBEDTLS_PRIVATE(own_cid)[MBEDTLS_SSL_CID_IN_LEN_MAX];
+ uint8_t MBEDTLS_PRIVATE(own_cid_len); /*!< The length of \c own_cid. */
+ uint8_t MBEDTLS_PRIVATE(negotiate_cid); /*!< This indicates whether the CID extension should
+ * be negotiated in the next handshake or not.
+ * Possible values are #MBEDTLS_SSL_CID_ENABLED
+ * and #MBEDTLS_SSL_CID_DISABLED. */
+#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
+
+#if defined(MBEDTLS_SSL_EARLY_DATA) && defined(MBEDTLS_SSL_CLI_C)
+ int MBEDTLS_PRIVATE(early_data_status);
+#endif /* MBEDTLS_SSL_EARLY_DATA && MBEDTLS_SSL_CLI_C */
+
+ /** Callback to export key block and master secret */
+ mbedtls_ssl_export_keys_t *MBEDTLS_PRIVATE(f_export_keys);
+ void *MBEDTLS_PRIVATE(p_export_keys); /*!< context for key export callback */
+
+ /** User data pointer or handle.
+ *
+ * The library sets this to \p 0 when creating a context and does not
+ * access it afterwards.
+ *
+ * \warning Serializing and restoring an SSL context with
+ * mbedtls_ssl_context_save() and mbedtls_ssl_context_load()
+ * does not currently restore the user data.
+ */
+ mbedtls_ssl_user_data_t MBEDTLS_PRIVATE(user_data);
+};
+
+/**
+ * \brief Return the name of the ciphersuite associated with the
+ * given ID
+ *
+ * \param ciphersuite_id SSL ciphersuite ID
+ *
+ * \return a string containing the ciphersuite name
+ */
+const char *mbedtls_ssl_get_ciphersuite_name(const int ciphersuite_id);
+
+/**
+ * \brief Return the ID of the ciphersuite associated with the
+ * given name
+ *
+ * \param ciphersuite_name SSL ciphersuite name
+ *
+ * \return the ID with the ciphersuite or 0 if not found
+ */
+int mbedtls_ssl_get_ciphersuite_id(const char *ciphersuite_name);
+
+/**
+ * \brief Initialize an SSL context
+ * Just makes the context ready for mbedtls_ssl_setup() or
+ * mbedtls_ssl_free()
+ *
+ * \param ssl SSL context
+ */
+void mbedtls_ssl_init(mbedtls_ssl_context *ssl);
+
+/**
+ * \brief Set up an SSL context for use
+ *
+ * \note No copy of the configuration context is made, it can be
+ * shared by many mbedtls_ssl_context structures.
+ *
+ * \warning The conf structure will be accessed during the session.
+ * It must not be modified or freed as long as the session
+ * is active.
+ *
+ * \warning This function must be called exactly once per context.
+ * Calling mbedtls_ssl_setup again is not supported, even
+ * if no session is active.
+ *
+ * \note If #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
+ * subsystem must have been initialized by calling
+ * psa_crypto_init() before calling this function.
+ *
+ * \param ssl SSL context
+ * \param conf SSL configuration to use
+ *
+ * \return 0 if successful, or MBEDTLS_ERR_SSL_ALLOC_FAILED if
+ * memory allocation failed
+ */
+int mbedtls_ssl_setup(mbedtls_ssl_context *ssl,
+ const mbedtls_ssl_config *conf);
+
+/**
+ * \brief Reset an already initialized SSL context for re-use
+ * while retaining application-set variables, function
+ * pointers and data.
+ *
+ * \param ssl SSL context
+ * \return 0 if successful, or MBEDTLS_ERR_SSL_ALLOC_FAILED or
+ MBEDTLS_ERR_SSL_HW_ACCEL_FAILED
+ */
+int mbedtls_ssl_session_reset(mbedtls_ssl_context *ssl);
+
+/**
+ * \brief Set the current endpoint type
+ *
+ * \param conf SSL configuration
+ * \param endpoint must be MBEDTLS_SSL_IS_CLIENT or MBEDTLS_SSL_IS_SERVER
+ */
+void mbedtls_ssl_conf_endpoint(mbedtls_ssl_config *conf, int endpoint);
+
+/**
+ * \brief Get the current endpoint type
+ *
+ * \param conf SSL configuration
+ *
+ * \return Endpoint type, either MBEDTLS_SSL_IS_CLIENT
+ * or MBEDTLS_SSL_IS_SERVER
+ */
+static inline int mbedtls_ssl_conf_get_endpoint(const mbedtls_ssl_config *conf)
+{
+ return conf->MBEDTLS_PRIVATE(endpoint);
+}
+
+/**
+ * \brief Set the transport type (TLS or DTLS).
+ * Default: TLS
+ *
+ * \note For DTLS, you must either provide a recv callback that
+ * doesn't block, or one that handles timeouts, see
+ * \c mbedtls_ssl_set_bio(). You also need to provide timer
+ * callbacks with \c mbedtls_ssl_set_timer_cb().
+ *
+ * \param conf SSL configuration
+ * \param transport transport type:
+ * MBEDTLS_SSL_TRANSPORT_STREAM for TLS,
+ * MBEDTLS_SSL_TRANSPORT_DATAGRAM for DTLS.
+ */
+void mbedtls_ssl_conf_transport(mbedtls_ssl_config *conf, int transport);
+
+/**
+ * \brief Set the certificate verification mode
+ * Default: NONE on server, REQUIRED on client
+ *
+ * \param conf SSL configuration
+ * \param authmode can be:
+ *
+ * MBEDTLS_SSL_VERIFY_NONE: peer certificate is not checked
+ * (default on server)
+ * (insecure on client)
+ *
+ * MBEDTLS_SSL_VERIFY_OPTIONAL: peer certificate is checked, however the
+ * handshake continues even if verification failed;
+ * mbedtls_ssl_get_verify_result() can be called after the
+ * handshake is complete.
+ *
+ * MBEDTLS_SSL_VERIFY_REQUIRED: peer *must* present a valid certificate,
+ * handshake is aborted if verification failed.
+ * (default on client)
+ *
+ * \note On client, MBEDTLS_SSL_VERIFY_REQUIRED is the recommended mode.
+ * With MBEDTLS_SSL_VERIFY_OPTIONAL, the user needs to call mbedtls_ssl_get_verify_result() at
+ * the right time(s), which may not be obvious, while REQUIRED always perform
+ * the verification as soon as possible. For example, REQUIRED was protecting
+ * against the "triple handshake" attack even before it was found.
+ */
+void mbedtls_ssl_conf_authmode(mbedtls_ssl_config *conf, int authmode);
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_EARLY_DATA)
+/**
+ * \brief Set the early data mode
+ * Default: disabled on server and client
+ *
+ * \param conf The SSL configuration to use.
+ * \param early_data_enabled can be:
+ *
+ * MBEDTLS_SSL_EARLY_DATA_DISABLED: early data functionality is disabled
+ * This is the default on client and server.
+ *
+ * MBEDTLS_SSL_EARLY_DATA_ENABLED: early data functionality is enabled and
+ * may be negotiated in the handshake. Application using
+ * early data functionality needs to be aware of the
+ * lack of replay protection of the early data application
+ * payloads.
+ *
+ * \warning This interface is experimental and may change without notice.
+ *
+ */
+void mbedtls_ssl_tls13_conf_early_data(mbedtls_ssl_config *conf,
+ int early_data_enabled);
+
+#if defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Set the maximum amount of 0-RTT data in bytes
+ * Default: #MBEDTLS_SSL_MAX_EARLY_DATA_SIZE
+ *
+ * This function sets the value of the max_early_data_size
+ * field of the early data indication extension included in
+ * the NewSessionTicket messages that the server may send.
+ *
+ * The value defines the maximum amount of 0-RTT data
+ * in bytes that a client will be allowed to send when using
+ * one of the tickets defined by the NewSessionTicket messages.
+ *
+ * \note When resuming a session using a ticket, if the server receives more
+ * early data than allowed for the ticket, it terminates the connection.
+ * The maximum amount of 0-RTT data should thus be large enough
+ * to allow a minimum of early data to be exchanged.
+ *
+ * \param[in] conf The SSL configuration to use.
+ * \param[in] max_early_data_size The maximum amount of 0-RTT data.
+ *
+ * \warning This interface is experimental and may change without notice.
+ *
+ */
+void mbedtls_ssl_tls13_conf_max_early_data_size(
+ mbedtls_ssl_config *conf, uint32_t max_early_data_size);
+#endif /* MBEDTLS_SSL_SRV_C */
+
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 && MBEDTLS_SSL_EARLY_DATA */
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+/**
+ * \brief Set the verification callback (Optional).
+ *
+ * If set, the provided verify callback is called for each
+ * certificate in the peer's CRT chain, including the trusted
+ * root. For more information, please see the documentation of
+ * \c mbedtls_x509_crt_verify().
+ *
+ * \note For per context callbacks and contexts, please use
+ * mbedtls_ssl_set_verify() instead.
+ *
+ * \param conf The SSL configuration to use.
+ * \param f_vrfy The verification callback to use during CRT verification.
+ * \param p_vrfy The opaque context to be passed to the callback.
+ */
+void mbedtls_ssl_conf_verify(mbedtls_ssl_config *conf,
+ int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
+ void *p_vrfy);
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+/**
+ * \brief Set the random number generator callback
+ *
+ * \param conf SSL configuration
+ * \param f_rng RNG function (mandatory)
+ * \param p_rng RNG parameter
+ */
+void mbedtls_ssl_conf_rng(mbedtls_ssl_config *conf,
+ int (*f_rng)(void *, unsigned char *, size_t),
+ void *p_rng);
+
+/**
+ * \brief Set the debug callback
+ *
+ * The callback has the following argument:
+ * void * opaque context for the callback
+ * int debug level
+ * const char * file name
+ * int line number
+ * const char * message
+ *
+ * \param conf SSL configuration
+ * \param f_dbg debug function
+ * \param p_dbg debug parameter
+ */
+void mbedtls_ssl_conf_dbg(mbedtls_ssl_config *conf,
+ void (*f_dbg)(void *, int, const char *, int, const char *),
+ void *p_dbg);
+
+/**
+ * \brief Return the SSL configuration structure associated
+ * with the given SSL context.
+ *
+ * \note The pointer returned by this function is guaranteed to
+ * remain valid until the context is freed.
+ *
+ * \param ssl The SSL context to query.
+ * \return Pointer to the SSL configuration associated with \p ssl.
+ */
+static inline const mbedtls_ssl_config *mbedtls_ssl_context_get_config(
+ const mbedtls_ssl_context *ssl)
+{
+ return ssl->MBEDTLS_PRIVATE(conf);
+}
+
+/**
+ * \brief Set the underlying BIO callbacks for write, read and
+ * read-with-timeout.
+ *
+ * \param ssl SSL context
+ * \param p_bio parameter (context) shared by BIO callbacks
+ * \param f_send write callback
+ * \param f_recv read callback
+ * \param f_recv_timeout blocking read callback with timeout.
+ *
+ * \note One of f_recv or f_recv_timeout can be NULL, in which case
+ * the other is used. If both are non-NULL, f_recv_timeout is
+ * used and f_recv is ignored (as if it were NULL).
+ *
+ * \note The two most common use cases are:
+ * - non-blocking I/O, f_recv != NULL, f_recv_timeout == NULL
+ * - blocking I/O, f_recv == NULL, f_recv_timeout != NULL
+ *
+ * \note For DTLS, you need to provide either a non-NULL
+ * f_recv_timeout callback, or a f_recv that doesn't block.
+ *
+ * \note See the documentations of \c mbedtls_ssl_send_t,
+ * \c mbedtls_ssl_recv_t and \c mbedtls_ssl_recv_timeout_t for
+ * the conventions those callbacks must follow.
+ *
+ * \note On some platforms, net_sockets.c provides
+ * \c mbedtls_net_send(), \c mbedtls_net_recv() and
+ * \c mbedtls_net_recv_timeout() that are suitable to be used
+ * here.
+ */
+void mbedtls_ssl_set_bio(mbedtls_ssl_context *ssl,
+ void *p_bio,
+ mbedtls_ssl_send_t *f_send,
+ mbedtls_ssl_recv_t *f_recv,
+ mbedtls_ssl_recv_timeout_t *f_recv_timeout);
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+
+#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
+
+
+/**
+ * \brief Configure the use of the Connection ID (CID)
+ * extension in the next handshake.
+ *
+ * Reference: RFC 9146 (or draft-ietf-tls-dtls-connection-id-05
+ * https://tools.ietf.org/html/draft-ietf-tls-dtls-connection-id-05
+ * for legacy version)
+ *
+ * The DTLS CID extension allows the reliable association of
+ * DTLS records to DTLS connections across changes in the
+ * underlying transport (changed IP and Port metadata) by
+ * adding explicit connection identifiers (CIDs) to the
+ * headers of encrypted DTLS records. The desired CIDs are
+ * configured by the application layer and are exchanged in
+ * new `ClientHello` / `ServerHello` extensions during the
+ * handshake, where each side indicates the CID it wants the
+ * peer to use when writing encrypted messages. The CIDs are
+ * put to use once records get encrypted: the stack discards
+ * any incoming records that don't include the configured CID
+ * in their header, and adds the peer's requested CID to the
+ * headers of outgoing messages.
+ *
+ * This API enables or disables the use of the CID extension
+ * in the next handshake and sets the value of the CID to
+ * be used for incoming messages.
+ *
+ * \param ssl The SSL context to configure. This must be initialized.
+ * \param enable This value determines whether the CID extension should
+ * be used or not. Possible values are:
+ * - MBEDTLS_SSL_CID_ENABLED to enable the use of the CID.
+ * - MBEDTLS_SSL_CID_DISABLED (default) to disable the use
+ * of the CID.
+ * \param own_cid The address of the readable buffer holding the CID we want
+ * the peer to use when sending encrypted messages to us.
+ * This may be \c NULL if \p own_cid_len is \c 0.
+ * This parameter is unused if \p enable is set to
+ * MBEDTLS_SSL_CID_DISABLED.
+ * \param own_cid_len The length of \p own_cid.
+ * This parameter is unused if \p enable is set to
+ * MBEDTLS_SSL_CID_DISABLED.
+ *
+ * \note The value of \p own_cid_len must match the value of the
+ * \c len parameter passed to mbedtls_ssl_conf_cid()
+ * when configuring the ::mbedtls_ssl_config that \p ssl
+ * is bound to.
+ *
+ * \note This CID configuration applies to subsequent handshakes
+ * performed on the SSL context \p ssl, but does not trigger
+ * one. You still have to call `mbedtls_ssl_handshake()`
+ * (for the initial handshake) or `mbedtls_ssl_renegotiate()`
+ * (for a renegotiation handshake) explicitly after a
+ * successful call to this function to run the handshake.
+ *
+ * \note This call cannot guarantee that the use of the CID
+ * will be successfully negotiated in the next handshake,
+ * because the peer might not support it. Specifically:
+ * - On the Client, enabling the use of the CID through
+ * this call implies that the `ClientHello` in the next
+ * handshake will include the CID extension, thereby
+ * offering the use of the CID to the server. Only if
+ * the `ServerHello` contains the CID extension, too,
+ * the CID extension will actually be put to use.
+ * - On the Server, enabling the use of the CID through
+ * this call implies that the server will look for
+ * the CID extension in a `ClientHello` from the client,
+ * and, if present, reply with a CID extension in its
+ * `ServerHello`.
+ *
+ * \note To check whether the use of the CID was negotiated
+ * after the subsequent handshake has completed, please
+ * use the API mbedtls_ssl_get_peer_cid().
+ *
+ * \warning If the use of the CID extension is enabled in this call
+ * and the subsequent handshake negotiates its use, Mbed TLS
+ * will silently drop every packet whose CID does not match
+ * the CID configured in \p own_cid. It is the responsibility
+ * of the user to adapt the underlying transport to take care
+ * of CID-based demultiplexing before handing datagrams to
+ * Mbed TLS.
+ *
+ * \return \c 0 on success. In this case, the CID configuration
+ * applies to the next handshake.
+ * \return A negative error code on failure.
+ */
+int mbedtls_ssl_set_cid(mbedtls_ssl_context *ssl,
+ int enable,
+ unsigned char const *own_cid,
+ size_t own_cid_len);
+
+/**
+ * \brief Get information about our request for usage of the CID
+ * extension in the current connection.
+ *
+ * \param ssl The SSL context to query.
+ * \param enabled The address at which to store whether the CID extension
+ * is requested to be used or not. If the CID is
+ * requested, `*enabled` is set to
+ * MBEDTLS_SSL_CID_ENABLED; otherwise, it is set to
+ * MBEDTLS_SSL_CID_DISABLED.
+ * \param own_cid The address of the buffer in which to store our own
+ * CID (if the CID extension is requested). This may be
+ * \c NULL in case the value of our CID isn't needed. If
+ * it is not \c NULL, \p own_cid_len must not be \c NULL.
+ * \param own_cid_len The address at which to store the size of our own CID
+ * (if the CID extension is requested). This is also the
+ * number of Bytes in \p own_cid that have been written.
+ * This may be \c NULL in case the length of our own CID
+ * isn't needed. If it is \c NULL, \p own_cid must be
+ * \c NULL, too.
+ *
+ *\note If we are requesting an empty CID this function sets
+ * `*enabled` to #MBEDTLS_SSL_CID_DISABLED (the rationale
+ * for this is that the resulting outcome is the
+ * same as if the CID extensions wasn't requested).
+ *
+ * \return \c 0 on success.
+ * \return A negative error code on failure.
+ */
+int mbedtls_ssl_get_own_cid(mbedtls_ssl_context *ssl,
+ int *enabled,
+ unsigned char own_cid[MBEDTLS_SSL_CID_OUT_LEN_MAX],
+ size_t *own_cid_len);
+
+/**
+ * \brief Get information about the use of the CID extension
+ * in the current connection.
+ *
+ * \param ssl The SSL context to query.
+ * \param enabled The address at which to store whether the CID extension
+ * is currently in use or not. If the CID is in use,
+ * `*enabled` is set to MBEDTLS_SSL_CID_ENABLED;
+ * otherwise, it is set to MBEDTLS_SSL_CID_DISABLED.
+ * \param peer_cid The address of the buffer in which to store the CID
+ * chosen by the peer (if the CID extension is used).
+ * This may be \c NULL in case the value of peer CID
+ * isn't needed. If it is not \c NULL, \p peer_cid_len
+ * must not be \c NULL.
+ * \param peer_cid_len The address at which to store the size of the CID
+ * chosen by the peer (if the CID extension is used).
+ * This is also the number of Bytes in \p peer_cid that
+ * have been written.
+ * This may be \c NULL in case the length of the peer CID
+ * isn't needed. If it is \c NULL, \p peer_cid must be
+ * \c NULL, too.
+ *
+ * \note This applies to the state of the CID negotiated in
+ * the last complete handshake. If a handshake is in
+ * progress, this function will attempt to complete
+ * the handshake first.
+ *
+ * \note If CID extensions have been exchanged but both client
+ * and server chose to use an empty CID, this function
+ * sets `*enabled` to #MBEDTLS_SSL_CID_DISABLED
+ * (the rationale for this is that the resulting
+ * communication is the same as if the CID extensions
+ * hadn't been used).
+ *
+ * \return \c 0 on success.
+ * \return A negative error code on failure.
+ */
+int mbedtls_ssl_get_peer_cid(mbedtls_ssl_context *ssl,
+ int *enabled,
+ unsigned char peer_cid[MBEDTLS_SSL_CID_OUT_LEN_MAX],
+ size_t *peer_cid_len);
+
+#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
+
+/**
+ * \brief Set the Maximum Transport Unit (MTU).
+ * Special value: 0 means unset (no limit).
+ * This represents the maximum size of a datagram payload
+ * handled by the transport layer (usually UDP) as determined
+ * by the network link and stack. In practice, this controls
+ * the maximum size datagram the DTLS layer will pass to the
+ * \c f_send() callback set using \c mbedtls_ssl_set_bio().
+ *
+ * \note The limit on datagram size is converted to a limit on
+ * record payload by subtracting the current overhead of
+ * encapsulation and encryption/authentication if any.
+ *
+ * \note This can be called at any point during the connection, for
+ * example when a Path Maximum Transfer Unit (PMTU)
+ * estimate becomes available from other sources,
+ * such as lower (or higher) protocol layers.
+ *
+ * \note This setting only controls the size of the packets we send,
+ * and does not restrict the size of the datagrams we're
+ * willing to receive. Client-side, you can request the
+ * server to use smaller records with \c
+ * mbedtls_ssl_conf_max_frag_len().
+ *
+ * \note If both a MTU and a maximum fragment length have been
+ * configured (or negotiated with the peer), the resulting
+ * lower limit on record payload (see first note) is used.
+ *
+ * \note This can only be used to decrease the maximum size
+ * of datagrams (hence records, see first note) sent. It
+ * cannot be used to increase the maximum size of records over
+ * the limit set by #MBEDTLS_SSL_OUT_CONTENT_LEN.
+ *
+ * \note Values lower than the current record layer expansion will
+ * result in an error when trying to send data.
+ *
+ * \param ssl SSL context
+ * \param mtu Value of the path MTU in bytes
+ */
+void mbedtls_ssl_set_mtu(mbedtls_ssl_context *ssl, uint16_t mtu);
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+/**
+ * \brief Set a connection-specific verification callback (optional).
+ *
+ * If set, the provided verify callback is called for each
+ * certificate in the peer's CRT chain, including the trusted
+ * root. For more information, please see the documentation of
+ * \c mbedtls_x509_crt_verify().
+ *
+ * \note This call is analogous to mbedtls_ssl_conf_verify() but
+ * binds the verification callback and context to an SSL context
+ * as opposed to an SSL configuration.
+ * If mbedtls_ssl_conf_verify() and mbedtls_ssl_set_verify()
+ * are both used, mbedtls_ssl_set_verify() takes precedence.
+ *
+ * \param ssl The SSL context to use.
+ * \param f_vrfy The verification callback to use during CRT verification.
+ * \param p_vrfy The opaque context to be passed to the callback.
+ */
+void mbedtls_ssl_set_verify(mbedtls_ssl_context *ssl,
+ int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
+ void *p_vrfy);
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+/**
+ * \brief Set the timeout period for mbedtls_ssl_read()
+ * (Default: no timeout.)
+ *
+ * \param conf SSL configuration context
+ * \param timeout Timeout value in milliseconds.
+ * Use 0 for no timeout (default).
+ *
+ * \note With blocking I/O, this will only work if a non-NULL
+ * \c f_recv_timeout was set with \c mbedtls_ssl_set_bio().
+ * With non-blocking I/O, this will only work if timer
+ * callbacks were set with \c mbedtls_ssl_set_timer_cb().
+ *
+ * \note With non-blocking I/O, you may also skip this function
+ * altogether and handle timeouts at the application layer.
+ */
+void mbedtls_ssl_conf_read_timeout(mbedtls_ssl_config *conf, uint32_t timeout);
+
+/**
+ * \brief Check whether a buffer contains a valid and authentic record
+ * that has not been seen before. (DTLS only).
+ *
+ * This function does not change the user-visible state
+ * of the SSL context. Its sole purpose is to provide
+ * an indication of the legitimacy of an incoming record.
+ *
+ * This can be useful e.g. in distributed server environments
+ * using the DTLS Connection ID feature, in which connections
+ * might need to be passed between service instances on a change
+ * of peer address, but where such disruptive operations should
+ * only happen after the validity of incoming records has been
+ * confirmed.
+ *
+ * \param ssl The SSL context to use.
+ * \param buf The address of the buffer holding the record to be checked.
+ * This must be a read/write buffer of length \p buflen Bytes.
+ * \param buflen The length of \p buf in Bytes.
+ *
+ * \note This routine only checks whether the provided buffer begins
+ * with a valid and authentic record that has not been seen
+ * before, but does not check potential data following the
+ * initial record. In particular, it is possible to pass DTLS
+ * datagrams containing multiple records, in which case only
+ * the first record is checked.
+ *
+ * \note This function modifies the input buffer \p buf. If you need
+ * to preserve the original record, you have to maintain a copy.
+ *
+ * \return \c 0 if the record is valid and authentic and has not been
+ * seen before.
+ * \return MBEDTLS_ERR_SSL_INVALID_MAC if the check completed
+ * successfully but the record was found to be not authentic.
+ * \return MBEDTLS_ERR_SSL_INVALID_RECORD if the check completed
+ * successfully but the record was found to be invalid for
+ * a reason different from authenticity checking.
+ * \return MBEDTLS_ERR_SSL_UNEXPECTED_RECORD if the check completed
+ * successfully but the record was found to be unexpected
+ * in the state of the SSL context, including replayed records.
+ * \return Another negative error code on different kinds of failure.
+ * In this case, the SSL context becomes unusable and needs
+ * to be freed or reset before reuse.
+ */
+int mbedtls_ssl_check_record(mbedtls_ssl_context const *ssl,
+ unsigned char *buf,
+ size_t buflen);
+
+/**
+ * \brief Set the timer callbacks (Mandatory for DTLS.)
+ *
+ * \param ssl SSL context
+ * \param p_timer parameter (context) shared by timer callbacks
+ * \param f_set_timer set timer callback
+ * \param f_get_timer get timer callback. Must return:
+ *
+ * \note See the documentation of \c mbedtls_ssl_set_timer_t and
+ * \c mbedtls_ssl_get_timer_t for the conventions this pair of
+ * callbacks must follow.
+ *
+ * \note On some platforms, timing.c provides
+ * \c mbedtls_timing_set_delay() and
+ * \c mbedtls_timing_get_delay() that are suitable for using
+ * here, except if using an event-driven style.
+ *
+ * \note See also the "DTLS tutorial" article in our knowledge base.
+ * https://mbed-tls.readthedocs.io/en/latest/kb/how-to/dtls-tutorial
+ */
+void mbedtls_ssl_set_timer_cb(mbedtls_ssl_context *ssl,
+ void *p_timer,
+ mbedtls_ssl_set_timer_t *f_set_timer,
+ mbedtls_ssl_get_timer_t *f_get_timer);
+
+#if defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Set the certificate selection callback (server-side only).
+ *
+ * If set, the callback is always called for each handshake,
+ * after `ClientHello` processing has finished.
+ *
+ * \param conf The SSL configuration to register the callback with.
+ * \param f_cert_cb The callback for selecting server certificate after
+ * `ClientHello` processing has finished.
+ */
+static inline void mbedtls_ssl_conf_cert_cb(mbedtls_ssl_config *conf,
+ mbedtls_ssl_hs_cb_t f_cert_cb)
+{
+ conf->MBEDTLS_PRIVATE(f_cert_cb) = f_cert_cb;
+}
+#endif /* MBEDTLS_SSL_SRV_C */
+
+/**
+ * \brief Callback type: generate and write session ticket
+ *
+ * \note This describes what a callback implementation should do.
+ * This callback should generate an encrypted and
+ * authenticated ticket for the session and write it to the
+ * output buffer. Here, ticket means the opaque ticket part
+ * of the NewSessionTicket structure of RFC 5077.
+ *
+ * \param p_ticket Context for the callback
+ * \param session SSL session to be written in the ticket
+ * \param start Start of the output buffer
+ * \param end End of the output buffer
+ * \param tlen On exit, holds the length written
+ * \param lifetime On exit, holds the lifetime of the ticket in seconds
+ *
+ * \return 0 if successful, or
+ * a specific MBEDTLS_ERR_XXX code.
+ */
+typedef int mbedtls_ssl_ticket_write_t(void *p_ticket,
+ const mbedtls_ssl_session *session,
+ unsigned char *start,
+ const unsigned char *end,
+ size_t *tlen,
+ uint32_t *lifetime);
+
+/**
+ * \brief Callback type: parse and load session ticket
+ *
+ * \note This describes what a callback implementation should do.
+ * This callback should parse a session ticket as generated
+ * by the corresponding mbedtls_ssl_ticket_write_t function,
+ * and, if the ticket is authentic and valid, load the
+ * session.
+ *
+ * \note The implementation is allowed to modify the first len
+ * bytes of the input buffer, eg to use it as a temporary
+ * area for the decrypted ticket contents.
+ *
+ * \param p_ticket Context for the callback
+ * \param session SSL session to be loaded
+ * \param buf Start of the buffer containing the ticket
+ * \param len Length of the ticket.
+ *
+ * \return 0 if successful, or
+ * MBEDTLS_ERR_SSL_INVALID_MAC if not authentic, or
+ * MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED if expired, or
+ * any other non-zero code for other failures.
+ */
+typedef int mbedtls_ssl_ticket_parse_t(void *p_ticket,
+ mbedtls_ssl_session *session,
+ unsigned char *buf,
+ size_t len);
+
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Configure SSL session ticket callbacks (server only).
+ * (Default: none.)
+ *
+ * \note On server, session tickets are enabled by providing
+ * non-NULL callbacks.
+ *
+ * \note On client, use \c mbedtls_ssl_conf_session_tickets().
+ *
+ * \param conf SSL configuration context
+ * \param f_ticket_write Callback for writing a ticket
+ * \param f_ticket_parse Callback for parsing a ticket
+ * \param p_ticket Context shared by the two callbacks
+ */
+void mbedtls_ssl_conf_session_tickets_cb(mbedtls_ssl_config *conf,
+ mbedtls_ssl_ticket_write_t *f_ticket_write,
+ mbedtls_ssl_ticket_parse_t *f_ticket_parse,
+ void *p_ticket);
+#endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_SRV_C */
+
+/**
+ * \brief Configure a key export callback.
+ * (Default: none.)
+ *
+ * This API can be used for two purposes:
+ * - Debugging: Use this API to e.g. generate an NSSKeylog
+ * file and use it to inspect encrypted traffic in tools
+ * such as Wireshark.
+ * - Application-specific export: Use this API to implement
+ * key exporters, e.g. for EAP-TLS or DTLS-SRTP.
+ *
+ *
+ * \param ssl The SSL context to which the export
+ * callback should be attached.
+ * \param f_export_keys The callback for the key export.
+ * \param p_export_keys The opaque context pointer to be passed to the
+ * callback \p f_export_keys.
+ */
+void mbedtls_ssl_set_export_keys_cb(mbedtls_ssl_context *ssl,
+ mbedtls_ssl_export_keys_t *f_export_keys,
+ void *p_export_keys);
+
+/** \brief Set the user data in an SSL configuration to a pointer.
+ *
+ * You can retrieve this value later with mbedtls_ssl_conf_get_user_data_p().
+ *
+ * \note The library stores \c p without accessing it. It is the responsibility
+ * of the caller to ensure that the pointer remains valid.
+ *
+ * \param conf The SSL configuration context to modify.
+ * \param p The new value of the user data.
+ */
+static inline void mbedtls_ssl_conf_set_user_data_p(
+ mbedtls_ssl_config *conf,
+ void *p)
+{
+ conf->MBEDTLS_PRIVATE(user_data).p = p;
+}
+
+/** \brief Set the user data in an SSL configuration to an integer.
+ *
+ * You can retrieve this value later with mbedtls_ssl_conf_get_user_data_n().
+ *
+ * \param conf The SSL configuration context to modify.
+ * \param n The new value of the user data.
+ */
+static inline void mbedtls_ssl_conf_set_user_data_n(
+ mbedtls_ssl_config *conf,
+ uintptr_t n)
+{
+ conf->MBEDTLS_PRIVATE(user_data).n = n;
+}
+
+/** \brief Retrieve the user data in an SSL configuration as a pointer.
+ *
+ * This is the value last set with mbedtls_ssl_conf_set_user_data_p(), or
+ * \c NULL if mbedtls_ssl_conf_set_user_data_p() has not previously been
+ * called. The value is undefined if mbedtls_ssl_conf_set_user_data_n() has
+ * been called without a subsequent call to mbedtls_ssl_conf_set_user_data_p().
+ *
+ * \param conf The SSL configuration context to modify.
+ * \return The current value of the user data.
+ */
+static inline void *mbedtls_ssl_conf_get_user_data_p(
+ mbedtls_ssl_config *conf)
+{
+ return conf->MBEDTLS_PRIVATE(user_data).p;
+}
+
+/** \brief Retrieve the user data in an SSL configuration as an integer.
+ *
+ * This is the value last set with mbedtls_ssl_conf_set_user_data_n(), or
+ * \c 0 if mbedtls_ssl_conf_set_user_data_n() has not previously been
+ * called. The value is undefined if mbedtls_ssl_conf_set_user_data_p() has
+ * been called without a subsequent call to mbedtls_ssl_conf_set_user_data_n().
+ *
+ * \param conf The SSL configuration context to modify.
+ * \return The current value of the user data.
+ */
+static inline uintptr_t mbedtls_ssl_conf_get_user_data_n(
+ mbedtls_ssl_config *conf)
+{
+ return conf->MBEDTLS_PRIVATE(user_data).n;
+}
+
+/** \brief Set the user data in an SSL context to a pointer.
+ *
+ * You can retrieve this value later with mbedtls_ssl_get_user_data_p().
+ *
+ * \note The library stores \c p without accessing it. It is the responsibility
+ * of the caller to ensure that the pointer remains valid.
+ *
+ * \param ssl The SSL context to modify.
+ * \param p The new value of the user data.
+ */
+static inline void mbedtls_ssl_set_user_data_p(
+ mbedtls_ssl_context *ssl,
+ void *p)
+{
+ ssl->MBEDTLS_PRIVATE(user_data).p = p;
+}
+
+/** \brief Set the user data in an SSL context to an integer.
+ *
+ * You can retrieve this value later with mbedtls_ssl_get_user_data_n().
+ *
+ * \param ssl The SSL context to modify.
+ * \param n The new value of the user data.
+ */
+static inline void mbedtls_ssl_set_user_data_n(
+ mbedtls_ssl_context *ssl,
+ uintptr_t n)
+{
+ ssl->MBEDTLS_PRIVATE(user_data).n = n;
+}
+
+/** \brief Retrieve the user data in an SSL context as a pointer.
+ *
+ * This is the value last set with mbedtls_ssl_set_user_data_p(), or
+ * \c NULL if mbedtls_ssl_set_user_data_p() has not previously been
+ * called. The value is undefined if mbedtls_ssl_set_user_data_n() has
+ * been called without a subsequent call to mbedtls_ssl_set_user_data_p().
+ *
+ * \param ssl The SSL context to modify.
+ * \return The current value of the user data.
+ */
+static inline void *mbedtls_ssl_get_user_data_p(
+ mbedtls_ssl_context *ssl)
+{
+ return ssl->MBEDTLS_PRIVATE(user_data).p;
+}
+
+/** \brief Retrieve the user data in an SSL context as an integer.
+ *
+ * This is the value last set with mbedtls_ssl_set_user_data_n(), or
+ * \c 0 if mbedtls_ssl_set_user_data_n() has not previously been
+ * called. The value is undefined if mbedtls_ssl_set_user_data_p() has
+ * been called without a subsequent call to mbedtls_ssl_set_user_data_n().
+ *
+ * \param ssl The SSL context to modify.
+ * \return The current value of the user data.
+ */
+static inline uintptr_t mbedtls_ssl_get_user_data_n(
+ mbedtls_ssl_context *ssl)
+{
+ return ssl->MBEDTLS_PRIVATE(user_data).n;
+}
+
+#if defined(MBEDTLS_SSL_ASYNC_PRIVATE)
+/**
+ * \brief Configure asynchronous private key operation callbacks.
+ *
+ * \param conf SSL configuration context
+ * \param f_async_sign Callback to start a signature operation. See
+ * the description of ::mbedtls_ssl_async_sign_t
+ * for more information. This may be \c NULL if the
+ * external processor does not support any signature
+ * operation; in this case the private key object
+ * associated with the certificate will be used.
+ * \param f_async_decrypt Callback to start a decryption operation. See
+ * the description of ::mbedtls_ssl_async_decrypt_t
+ * for more information. This may be \c NULL if the
+ * external processor does not support any decryption
+ * operation; in this case the private key object
+ * associated with the certificate will be used.
+ * \param f_async_resume Callback to resume an asynchronous operation. See
+ * the description of ::mbedtls_ssl_async_resume_t
+ * for more information. This may not be \c NULL unless
+ * \p f_async_sign and \p f_async_decrypt are both
+ * \c NULL.
+ * \param f_async_cancel Callback to cancel an asynchronous operation. See
+ * the description of ::mbedtls_ssl_async_cancel_t
+ * for more information. This may be \c NULL if
+ * no cleanup is needed.
+ * \param config_data A pointer to configuration data which can be
+ * retrieved with
+ * mbedtls_ssl_conf_get_async_config_data(). The
+ * library stores this value without dereferencing it.
+ */
+void mbedtls_ssl_conf_async_private_cb(mbedtls_ssl_config *conf,
+ mbedtls_ssl_async_sign_t *f_async_sign,
+ mbedtls_ssl_async_decrypt_t *f_async_decrypt,
+ mbedtls_ssl_async_resume_t *f_async_resume,
+ mbedtls_ssl_async_cancel_t *f_async_cancel,
+ void *config_data);
+
+/**
+ * \brief Retrieve the configuration data set by
+ * mbedtls_ssl_conf_async_private_cb().
+ *
+ * \param conf SSL configuration context
+ * \return The configuration data set by
+ * mbedtls_ssl_conf_async_private_cb().
+ */
+void *mbedtls_ssl_conf_get_async_config_data(const mbedtls_ssl_config *conf);
+
+/**
+ * \brief Retrieve the asynchronous operation user context.
+ *
+ * \note This function may only be called while a handshake
+ * is in progress.
+ *
+ * \param ssl The SSL context to access.
+ *
+ * \return The asynchronous operation user context that was last
+ * set during the current handshake. If
+ * mbedtls_ssl_set_async_operation_data() has not yet been
+ * called during the current handshake, this function returns
+ * \c NULL.
+ */
+void *mbedtls_ssl_get_async_operation_data(const mbedtls_ssl_context *ssl);
+
+/**
+ * \brief Retrieve the asynchronous operation user context.
+ *
+ * \note This function may only be called while a handshake
+ * is in progress.
+ *
+ * \param ssl The SSL context to access.
+ * \param ctx The new value of the asynchronous operation user context.
+ * Call mbedtls_ssl_get_async_operation_data() later during the
+ * same handshake to retrieve this value.
+ */
+void mbedtls_ssl_set_async_operation_data(mbedtls_ssl_context *ssl,
+ void *ctx);
+#endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
+
+/**
+ * \brief Callback type: generate a cookie
+ *
+ * \param ctx Context for the callback
+ * \param p Buffer to write to,
+ * must be updated to point right after the cookie
+ * \param end Pointer to one past the end of the output buffer
+ * \param info Client ID info that was passed to
+ * \c mbedtls_ssl_set_client_transport_id()
+ * \param ilen Length of info in bytes
+ *
+ * \return The callback must return 0 on success,
+ * or a negative error code.
+ */
+typedef int mbedtls_ssl_cookie_write_t(void *ctx,
+ unsigned char **p, unsigned char *end,
+ const unsigned char *info, size_t ilen);
+
+/**
+ * \brief Callback type: verify a cookie
+ *
+ * \param ctx Context for the callback
+ * \param cookie Cookie to verify
+ * \param clen Length of cookie
+ * \param info Client ID info that was passed to
+ * \c mbedtls_ssl_set_client_transport_id()
+ * \param ilen Length of info in bytes
+ *
+ * \return The callback must return 0 if cookie is valid,
+ * or a negative error code.
+ */
+typedef int mbedtls_ssl_cookie_check_t(void *ctx,
+ const unsigned char *cookie, size_t clen,
+ const unsigned char *info, size_t ilen);
+
+#if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Register callbacks for DTLS cookies
+ * (Server only. DTLS only.)
+ *
+ * Default: dummy callbacks that fail, in order to force you to
+ * register working callbacks (and initialize their context).
+ *
+ * To disable HelloVerifyRequest, register NULL callbacks.
+ *
+ * \warning Disabling hello verification allows your server to be used
+ * for amplification in DoS attacks against other hosts.
+ * Only disable if you known this can't happen in your
+ * particular environment.
+ *
+ * \note See comments on \c mbedtls_ssl_handshake() about handling
+ * the MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED that is expected
+ * on the first handshake attempt when this is enabled.
+ *
+ * \note This is also necessary to handle client reconnection from
+ * the same port as described in RFC 6347 section 4.2.8 (only
+ * the variant with cookies is supported currently). See
+ * comments on \c mbedtls_ssl_read() for details.
+ *
+ * \param conf SSL configuration
+ * \param f_cookie_write Cookie write callback
+ * \param f_cookie_check Cookie check callback
+ * \param p_cookie Context for both callbacks
+ */
+void mbedtls_ssl_conf_dtls_cookies(mbedtls_ssl_config *conf,
+ mbedtls_ssl_cookie_write_t *f_cookie_write,
+ mbedtls_ssl_cookie_check_t *f_cookie_check,
+ void *p_cookie);
+
+/**
+ * \brief Set client's transport-level identification info.
+ * (Server only. DTLS only.)
+ *
+ * This is usually the IP address (and port), but could be
+ * anything identify the client depending on the underlying
+ * network stack. Used for HelloVerifyRequest with DTLS.
+ * This is *not* used to route the actual packets.
+ *
+ * \param ssl SSL context
+ * \param info Transport-level info identifying the client (eg IP + port)
+ * \param ilen Length of info in bytes
+ *
+ * \note An internal copy is made, so the info buffer can be reused.
+ *
+ * \return 0 on success,
+ * MBEDTLS_ERR_SSL_BAD_INPUT_DATA if used on client,
+ * MBEDTLS_ERR_SSL_ALLOC_FAILED if out of memory.
+ */
+int mbedtls_ssl_set_client_transport_id(mbedtls_ssl_context *ssl,
+ const unsigned char *info,
+ size_t ilen);
+
+#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY && MBEDTLS_SSL_SRV_C */
+
+#if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
+/**
+ * \brief Enable or disable anti-replay protection for DTLS.
+ * (DTLS only, no effect on TLS.)
+ * Default: enabled.
+ *
+ * \param conf SSL configuration
+ * \param mode MBEDTLS_SSL_ANTI_REPLAY_ENABLED or MBEDTLS_SSL_ANTI_REPLAY_DISABLED.
+ *
+ * \warning Disabling this is a security risk unless the application
+ * protocol handles duplicated packets in a safe way. You
+ * should not disable this without careful consideration.
+ * However, if your application already detects duplicated
+ * packets and needs information about them to adjust its
+ * transmission strategy, then you'll want to disable this.
+ */
+void mbedtls_ssl_conf_dtls_anti_replay(mbedtls_ssl_config *conf, char mode);
+#endif /* MBEDTLS_SSL_DTLS_ANTI_REPLAY */
+
+/**
+ * \brief Set a limit on the number of records with a bad MAC
+ * before terminating the connection.
+ * (DTLS only, no effect on TLS.)
+ * Default: 0 (disabled).
+ *
+ * \param conf SSL configuration
+ * \param limit Limit, or 0 to disable.
+ *
+ * \note If the limit is N, then the connection is terminated when
+ * the Nth non-authentic record is seen.
+ *
+ * \note Records with an invalid header are not counted, only the
+ * ones going through the authentication-decryption phase.
+ *
+ * \note This is a security trade-off related to the fact that it's
+ * often relatively easy for an active attacker to inject UDP
+ * datagrams. On one hand, setting a low limit here makes it
+ * easier for such an attacker to forcibly terminated a
+ * connection. On the other hand, a high limit or no limit
+ * might make us waste resources checking authentication on
+ * many bogus packets.
+ */
+void mbedtls_ssl_conf_dtls_badmac_limit(mbedtls_ssl_config *conf, unsigned limit);
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+
+/**
+ * \brief Allow or disallow packing of multiple handshake records
+ * within a single datagram.
+ *
+ * \param ssl The SSL context to configure.
+ * \param allow_packing This determines whether datagram packing may
+ * be used or not. A value of \c 0 means that every
+ * record will be sent in a separate datagram; a
+ * value of \c 1 means that, if space permits,
+ * multiple handshake messages (including CCS) belonging to
+ * a single flight may be packed within a single datagram.
+ *
+ * \note This is enabled by default and should only be disabled
+ * for test purposes, or if datagram packing causes
+ * interoperability issues with peers that don't support it.
+ *
+ * \note Allowing datagram packing reduces the network load since
+ * there's less overhead if multiple messages share the same
+ * datagram. Also, it increases the handshake efficiency
+ * since messages belonging to a single datagram will not
+ * be reordered in transit, and so future message buffering
+ * or flight retransmission (if no buffering is used) as
+ * means to deal with reordering are needed less frequently.
+ *
+ * \note Application records are not affected by this option and
+ * are currently always sent in separate datagrams.
+ *
+ */
+void mbedtls_ssl_set_datagram_packing(mbedtls_ssl_context *ssl,
+ unsigned allow_packing);
+
+/**
+ * \brief Set retransmit timeout values for the DTLS handshake.
+ * (DTLS only, no effect on TLS.)
+ *
+ * \param conf SSL configuration
+ * \param min Initial timeout value in milliseconds.
+ * Default: 1000 (1 second).
+ * \param max Maximum timeout value in milliseconds.
+ * Default: 60000 (60 seconds).
+ *
+ * \note Default values are from RFC 6347 section 4.2.4.1.
+ *
+ * \note The 'min' value should typically be slightly above the
+ * expected round-trip time to your peer, plus whatever time
+ * it takes for the peer to process the message. For example,
+ * if your RTT is about 600ms and you peer needs up to 1s to
+ * do the cryptographic operations in the handshake, then you
+ * should set 'min' slightly above 1600. Lower values of 'min'
+ * might cause spurious resends which waste network resources,
+ * while larger value of 'min' will increase overall latency
+ * on unreliable network links.
+ *
+ * \note The more unreliable your network connection is, the larger
+ * your max / min ratio needs to be in order to achieve
+ * reliable handshakes.
+ *
+ * \note Messages are retransmitted up to log2(ceil(max/min)) times.
+ * For example, if min = 1s and max = 5s, the retransmit plan
+ * goes: send ... 1s -> resend ... 2s -> resend ... 4s ->
+ * resend ... 5s -> give up and return a timeout error.
+ */
+void mbedtls_ssl_conf_handshake_timeout(mbedtls_ssl_config *conf, uint32_t min, uint32_t max);
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+#if defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Set the session cache callbacks (server-side only)
+ * If not set, no session resuming is done (except if session
+ * tickets are enabled too).
+ *
+ * The session cache has the responsibility to check for stale
+ * entries based on timeout. See RFC 5246 for recommendations.
+ *
+ * Warning: session.peer_cert is cleared by the SSL/TLS layer on
+ * connection shutdown, so do not cache the pointer! Either set
+ * it to NULL or make a full copy of the certificate.
+ *
+ * The get callback is called once during the initial handshake
+ * to enable session resuming. The get function has the
+ * following parameters: (void *parameter, mbedtls_ssl_session *session)
+ * If a valid entry is found, it should fill the master of
+ * the session object with the cached values and return 0,
+ * return 1 otherwise. Optionally peer_cert can be set as well
+ * if it is properly present in cache entry.
+ *
+ * The set callback is called once during the initial handshake
+ * to enable session resuming after the entire handshake has
+ * been finished. The set function has the following parameters:
+ * (void *parameter, const mbedtls_ssl_session *session). The function
+ * should create a cache entry for future retrieval based on
+ * the data in the session structure and should keep in mind
+ * that the mbedtls_ssl_session object presented (and all its referenced
+ * data) is cleared by the SSL/TLS layer when the connection is
+ * terminated. It is recommended to add metadata to determine if
+ * an entry is still valid in the future. Return 0 if
+ * successfully cached, return 1 otherwise.
+ *
+ * \param conf SSL configuration
+ * \param p_cache parameter (context) for both callbacks
+ * \param f_get_cache session get callback
+ * \param f_set_cache session set callback
+ */
+void mbedtls_ssl_conf_session_cache(mbedtls_ssl_config *conf,
+ void *p_cache,
+ mbedtls_ssl_cache_get_t *f_get_cache,
+ mbedtls_ssl_cache_set_t *f_set_cache);
+#endif /* MBEDTLS_SSL_SRV_C */
+
+#if defined(MBEDTLS_SSL_CLI_C)
+/**
+ * \brief Load a session for session resumption.
+ *
+ * Sessions loaded through this call will be considered
+ * for session resumption in the next handshake.
+ *
+ * \note Even if this call succeeds, it is not guaranteed that
+ * the next handshake will indeed be shortened through the
+ * use of session resumption: The server is always free
+ * to reject any attempt for resumption and fall back to
+ * a full handshake.
+ *
+ * \note This function can handle a variety of mechanisms for session
+ * resumption: For TLS 1.2, both session ID-based resumption and
+ * ticket-based resumption will be considered. For TLS 1.3,
+ * once implemented, sessions equate to tickets, and loading
+ * one or more sessions via this call will lead to their
+ * corresponding tickets being advertised as resumption PSKs
+ * by the client.
+ *
+ * \note Calling this function multiple times will only be useful
+ * once TLS 1.3 is supported. For TLS 1.2 connections, this
+ * function should be called at most once.
+ *
+ * \param ssl The SSL context representing the connection which should
+ * be attempted to be setup using session resumption. This
+ * must be initialized via mbedtls_ssl_init() and bound to
+ * an SSL configuration via mbedtls_ssl_setup(), but
+ * the handshake must not yet have been started.
+ * \param session The session to be considered for session resumption.
+ * This must be a session previously exported via
+ * mbedtls_ssl_get_session(), and potentially serialized and
+ * deserialized through mbedtls_ssl_session_save() and
+ * mbedtls_ssl_session_load() in the meantime.
+ *
+ * \return \c 0 if successful.
+ * \return \c MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE if the session
+ * could not be loaded because of an implementation limitation.
+ * This error is non-fatal, and has no observable effect on
+ * the SSL context or the session that was attempted to be loaded.
+ * \return Another negative error code on other kinds of failure.
+ *
+ * \sa mbedtls_ssl_get_session()
+ * \sa mbedtls_ssl_session_load()
+ */
+int mbedtls_ssl_set_session(mbedtls_ssl_context *ssl, const mbedtls_ssl_session *session);
+#endif /* MBEDTLS_SSL_CLI_C */
+
+/**
+ * \brief Load serialized session data into a session structure.
+ * On client, this can be used for loading saved sessions
+ * before resuming them with mbedtls_ssl_set_session().
+ * On server, this can be used for alternative implementations
+ * of session cache or session tickets.
+ *
+ * \warning If a peer certificate chain is associated with the session,
+ * the serialized state will only contain the peer's
+ * end-entity certificate and the result of the chain
+ * verification (unless verification was disabled), but not
+ * the rest of the chain.
+ *
+ * \see mbedtls_ssl_session_save()
+ * \see mbedtls_ssl_set_session()
+ *
+ * \param session The session structure to be populated. It must have been
+ * initialised with mbedtls_ssl_session_init() but not
+ * populated yet.
+ * \param buf The buffer holding the serialized session data. It must be a
+ * readable buffer of at least \p len bytes.
+ * \param len The size of the serialized data in bytes.
+ *
+ * \return \c 0 if successful.
+ * \return #MBEDTLS_ERR_SSL_ALLOC_FAILED if memory allocation failed.
+ * \return #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if input data is invalid.
+ * \return #MBEDTLS_ERR_SSL_VERSION_MISMATCH if the serialized data
+ * was generated in a different version or configuration of
+ * Mbed TLS.
+ * \return Another negative value for other kinds of errors (for
+ * example, unsupported features in the embedded certificate).
+ */
+int mbedtls_ssl_session_load(mbedtls_ssl_session *session,
+ const unsigned char *buf,
+ size_t len);
+
+/**
+ * \brief Save session structure as serialized data in a buffer.
+ * On client, this can be used for saving session data,
+ * potentially in non-volatile storage, for resuming later.
+ * On server, this can be used for alternative implementations
+ * of session cache or session tickets.
+ *
+ * \see mbedtls_ssl_session_load()
+ *
+ * \param session The session structure to be saved.
+ * \param buf The buffer to write the serialized data to. It must be a
+ * writeable buffer of at least \p buf_len bytes, or may be \c
+ * NULL if \p buf_len is \c 0.
+ * \param buf_len The number of bytes available for writing in \p buf.
+ * \param olen The size in bytes of the data that has been or would have
+ * been written. It must point to a valid \c size_t.
+ *
+ * \note \p olen is updated to the correct value regardless of
+ * whether \p buf_len was large enough. This makes it possible
+ * to determine the necessary size by calling this function
+ * with \p buf set to \c NULL and \p buf_len to \c 0.
+ *
+ * \return \c 0 if successful.
+ * \return #MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL if \p buf is too small.
+ */
+int mbedtls_ssl_session_save(const mbedtls_ssl_session *session,
+ unsigned char *buf,
+ size_t buf_len,
+ size_t *olen);
+
+/**
+ * \brief Set the list of allowed ciphersuites and the preference
+ * order. First in the list has the highest preference.
+ *
+ * For TLS 1.2, the notion of ciphersuite determines both
+ * the key exchange mechanism and the suite of symmetric
+ * algorithms to be used during and after the handshake.
+ *
+ * For TLS 1.3 (in development), the notion of ciphersuite
+ * only determines the suite of symmetric algorithms to be
+ * used during and after the handshake, while key exchange
+ * mechanisms are configured separately.
+ *
+ * In Mbed TLS, ciphersuites for both TLS 1.2 and TLS 1.3
+ * are configured via this function. For users of TLS 1.3,
+ * there will be separate API for the configuration of key
+ * exchange mechanisms.
+ *
+ * The list of ciphersuites passed to this function may
+ * contain a mixture of TLS 1.2 and TLS 1.3 ciphersuite
+ * identifiers. This is useful if negotiation of TLS 1.3
+ * should be attempted, but a fallback to TLS 1.2 would
+ * be tolerated.
+ *
+ * \note By default, the server chooses its preferred
+ * ciphersuite among those that the client supports. If
+ * mbedtls_ssl_conf_preference_order() is called to prefer
+ * the client's preferences, the server instead chooses
+ * the client's preferred ciphersuite among those that
+ * the server supports.
+ *
+ * \warning The ciphersuites array \p ciphersuites is not copied.
+ * It must remain valid for the lifetime of the SSL
+ * configuration \p conf.
+ *
+ * \param conf The SSL configuration to modify.
+ * \param ciphersuites A 0-terminated list of IANA identifiers of supported
+ * ciphersuites, accessible through \c MBEDTLS_TLS_XXX
+ * and \c MBEDTLS_TLS1_3_XXX macros defined in
+ * ssl_ciphersuites.h.
+ */
+void mbedtls_ssl_conf_ciphersuites(mbedtls_ssl_config *conf,
+ const int *ciphersuites);
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+/**
+ * \brief Set the supported key exchange modes for TLS 1.3 connections.
+ *
+ * In contrast to TLS 1.2, the ciphersuite concept in TLS 1.3 does not
+ * include the choice of key exchange mechanism. It is therefore not
+ * covered by the API mbedtls_ssl_conf_ciphersuites(). See the
+ * documentation of mbedtls_ssl_conf_ciphersuites() for more
+ * information on the ciphersuite concept in TLS 1.2 and TLS 1.3.
+ *
+ * The present function is specific to TLS 1.3 and allows users to
+ * configure the set of supported key exchange mechanisms in TLS 1.3.
+ *
+ * \param conf The SSL configuration the change should apply to.
+ * \param kex_modes A bitwise combination of one or more of the following:
+ * - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK
+ * This flag enables pure-PSK key exchanges.
+ * - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL
+ * This flag enables combined PSK-ephemeral key exchanges.
+ * - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL
+ * This flag enables pure-ephemeral key exchanges.
+ * For convenience, the following pre-defined macros are
+ * available for combinations of the above:
+ * - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_ALL
+ * Includes all of pure-PSK, PSK-ephemeral and pure-ephemeral.
+ * - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ALL
+ * Includes both pure-PSK and combined PSK-ephemeral
+ * key exchanges, but excludes pure-ephemeral key exchanges.
+ * - MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ALL
+ * Includes both pure-ephemeral and combined PSK-ephemeral
+ * key exchanges.
+ *
+ * \note If a PSK-based key exchange mode shall be supported, applications
+ * must also use the APIs mbedtls_ssl_conf_psk() or
+ * mbedtls_ssl_conf_psk_cb() or mbedtls_ssl_conf_psk_opaque()
+ * to configure the PSKs to be used.
+ *
+ * \note If a pure-ephemeral key exchange mode shall be supported,
+ * server-side applications must also provide a certificate via
+ * mbedtls_ssl_conf_own_cert().
+ *
+ */
+
+void mbedtls_ssl_conf_tls13_key_exchange_modes(mbedtls_ssl_config *conf,
+ const int kex_modes);
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
+
+#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
+#define MBEDTLS_SSL_UNEXPECTED_CID_IGNORE 0
+#define MBEDTLS_SSL_UNEXPECTED_CID_FAIL 1
+/**
+ * \brief Specify the length of Connection IDs for incoming
+ * encrypted DTLS records, as well as the behaviour
+ * on unexpected CIDs.
+ *
+ * By default, the CID length is set to \c 0,
+ * and unexpected CIDs are silently ignored.
+ *
+ * \param conf The SSL configuration to modify.
+ * \param len The length in Bytes of the CID fields in encrypted
+ * DTLS records using the CID mechanism. This must
+ * not be larger than #MBEDTLS_SSL_CID_OUT_LEN_MAX.
+ * \param ignore_other_cids This determines the stack's behaviour when
+ * receiving a record with an unexpected CID.
+ * Possible values are:
+ * - #MBEDTLS_SSL_UNEXPECTED_CID_IGNORE
+ * In this case, the record is silently ignored.
+ * - #MBEDTLS_SSL_UNEXPECTED_CID_FAIL
+ * In this case, the stack fails with the specific
+ * error code #MBEDTLS_ERR_SSL_UNEXPECTED_CID.
+ *
+ * \note The CID specification allows implementations to either
+ * use a common length for all incoming connection IDs or
+ * allow variable-length incoming IDs. Mbed TLS currently
+ * requires a common length for all connections sharing the
+ * same SSL configuration; this allows simpler parsing of
+ * record headers.
+ *
+ * \return \c 0 on success.
+ * \return #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if \p len
+ * is too large.
+ */
+int mbedtls_ssl_conf_cid(mbedtls_ssl_config *conf, size_t len,
+ int ignore_other_cids);
+#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+/**
+ * \brief Set the X.509 security profile used for verification
+ *
+ * \note The restrictions are enforced for all certificates in the
+ * chain. However, signatures in the handshake are not covered
+ * by this setting but by \b mbedtls_ssl_conf_sig_hashes().
+ *
+ * \param conf SSL configuration
+ * \param profile Profile to use
+ */
+void mbedtls_ssl_conf_cert_profile(mbedtls_ssl_config *conf,
+ const mbedtls_x509_crt_profile *profile);
+
+/**
+ * \brief Set the data required to verify peer certificate
+ *
+ * \note See \c mbedtls_x509_crt_verify() for notes regarding the
+ * parameters ca_chain (maps to trust_ca for that function)
+ * and ca_crl.
+ *
+ * \param conf SSL configuration
+ * \param ca_chain trusted CA chain (meaning all fully trusted top-level CAs)
+ * \param ca_crl trusted CA CRLs
+ */
+void mbedtls_ssl_conf_ca_chain(mbedtls_ssl_config *conf,
+ mbedtls_x509_crt *ca_chain,
+ mbedtls_x509_crl *ca_crl);
+
+#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+/**
+ * \brief Set DN hints sent to client in CertificateRequest message
+ *
+ * \note If not set, subject distinguished names (DNs) are taken
+ * from \c mbedtls_ssl_conf_ca_chain()
+ * or \c mbedtls_ssl_set_hs_ca_chain())
+ *
+ * \param conf SSL configuration
+ * \param crt crt chain whose subject DNs are issuer DNs of client certs
+ * from which the client should select client peer certificate.
+ */
+static inline
+void mbedtls_ssl_conf_dn_hints(mbedtls_ssl_config *conf,
+ const mbedtls_x509_crt *crt)
+{
+ conf->MBEDTLS_PRIVATE(dn_hints) = crt;
+}
+#endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
+
+#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
+/**
+ * \brief Set the trusted certificate callback.
+ *
+ * This API allows to register the set of trusted certificates
+ * through a callback, instead of a linked list as configured
+ * by mbedtls_ssl_conf_ca_chain().
+ *
+ * This is useful for example in contexts where a large number
+ * of CAs are used, and the inefficiency of maintaining them
+ * in a linked list cannot be tolerated. It is also useful when
+ * the set of trusted CAs needs to be modified frequently.
+ *
+ * See the documentation of `mbedtls_x509_crt_ca_cb_t` for
+ * more information.
+ *
+ * \param conf The SSL configuration to register the callback with.
+ * \param f_ca_cb The trusted certificate callback to use when verifying
+ * certificate chains.
+ * \param p_ca_cb The context to be passed to \p f_ca_cb (for example,
+ * a reference to a trusted CA database).
+ *
+ * \note This API is incompatible with mbedtls_ssl_conf_ca_chain():
+ * Any call to this function overwrites the values set through
+ * earlier calls to mbedtls_ssl_conf_ca_chain() or
+ * mbedtls_ssl_conf_ca_cb().
+ *
+ * \note This API is incompatible with CA indication in
+ * CertificateRequest messages: A server-side SSL context which
+ * is bound to an SSL configuration that uses a CA callback
+ * configured via mbedtls_ssl_conf_ca_cb(), and which requires
+ * client authentication, will send an empty CA list in the
+ * corresponding CertificateRequest message.
+ *
+ * \note This API is incompatible with mbedtls_ssl_set_hs_ca_chain():
+ * If an SSL context is bound to an SSL configuration which uses
+ * CA callbacks configured via mbedtls_ssl_conf_ca_cb(), then
+ * calls to mbedtls_ssl_set_hs_ca_chain() have no effect.
+ *
+ * \note The use of this API disables the use of restartable ECC
+ * during X.509 CRT signature verification (but doesn't affect
+ * other uses).
+ *
+ * \warning This API is incompatible with the use of CRLs. Any call to
+ * mbedtls_ssl_conf_ca_cb() unsets CRLs configured through
+ * earlier calls to mbedtls_ssl_conf_ca_chain().
+ *
+ * \warning In multi-threaded environments, the callback \p f_ca_cb
+ * must be thread-safe, and it is the user's responsibility
+ * to guarantee this (for example through a mutex
+ * contained in the callback context pointed to by \p p_ca_cb).
+ */
+void mbedtls_ssl_conf_ca_cb(mbedtls_ssl_config *conf,
+ mbedtls_x509_crt_ca_cb_t f_ca_cb,
+ void *p_ca_cb);
+#endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */
+
+/**
+ * \brief Set own certificate chain and private key
+ *
+ * \note own_cert should contain in order from the bottom up your
+ * certificate chain. The top certificate (self-signed)
+ * can be omitted.
+ *
+ * \note On server, this function can be called multiple times to
+ * provision more than one cert/key pair (eg one ECDSA, one
+ * RSA with SHA-256, one RSA with SHA-1). An adequate
+ * certificate will be selected according to the client's
+ * advertised capabilities. In case multiple certificates are
+ * adequate, preference is given to the one set by the first
+ * call to this function, then second, etc.
+ *
+ * \note On client, only the first call has any effect. That is,
+ * only one client certificate can be provisioned. The
+ * server's preferences in its CertificateRequest message will
+ * be ignored and our only cert will be sent regardless of
+ * whether it matches those preferences - the server can then
+ * decide what it wants to do with it.
+ *
+ * \note The provided \p pk_key needs to match the public key in the
+ * first certificate in \p own_cert, or all handshakes using
+ * that certificate will fail. It is your responsibility
+ * to ensure that; this function will not perform any check.
+ * You may use mbedtls_pk_check_pair() in order to perform
+ * this check yourself, but be aware that this function can
+ * be computationally expensive on some key types.
+ *
+ * \param conf SSL configuration
+ * \param own_cert own public certificate chain
+ * \param pk_key own private key
+ *
+ * \return 0 on success or MBEDTLS_ERR_SSL_ALLOC_FAILED
+ */
+int mbedtls_ssl_conf_own_cert(mbedtls_ssl_config *conf,
+ mbedtls_x509_crt *own_cert,
+ mbedtls_pk_context *pk_key);
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+#if defined(MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED)
+/**
+ * \brief Configure pre-shared keys (PSKs) and their
+ * identities to be used in PSK-based ciphersuites.
+ *
+ * Only one PSK can be registered, through either
+ * mbedtls_ssl_conf_psk() or mbedtls_ssl_conf_psk_opaque().
+ * If you attempt to register more than one PSK, this function
+ * fails, though this may change in future versions, which
+ * may add support for multiple PSKs.
+ *
+ * \note This is mainly useful for clients. Servers will usually
+ * want to use \c mbedtls_ssl_conf_psk_cb() instead.
+ *
+ * \note A PSK set by \c mbedtls_ssl_set_hs_psk() in the PSK callback
+ * takes precedence over a PSK configured by this function.
+ *
+ * \param conf The SSL configuration to register the PSK with.
+ * \param psk The pointer to the pre-shared key to use.
+ * \param psk_len The length of the pre-shared key in bytes.
+ * \param psk_identity The pointer to the pre-shared key identity.
+ * \param psk_identity_len The length of the pre-shared key identity
+ * in bytes.
+ *
+ * \note The PSK and its identity are copied internally and
+ * hence need not be preserved by the caller for the lifetime
+ * of the SSL configuration.
+ *
+ * \return \c 0 if successful.
+ * \return #MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE if no more PSKs
+ * can be configured. In this case, the old PSK(s) remain intact.
+ * \return Another negative error code on other kinds of failure.
+ */
+int mbedtls_ssl_conf_psk(mbedtls_ssl_config *conf,
+ const unsigned char *psk, size_t psk_len,
+ const unsigned char *psk_identity, size_t psk_identity_len);
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+/**
+ * \brief Configure one or more opaque pre-shared keys (PSKs) and
+ * their identities to be used in PSK-based ciphersuites.
+ *
+ * Only one PSK can be registered, through either
+ * mbedtls_ssl_conf_psk() or mbedtls_ssl_conf_psk_opaque().
+ * If you attempt to register more than one PSK, this function
+ * fails, though this may change in future versions, which
+ * may add support for multiple PSKs.
+ *
+ * \note This is mainly useful for clients. Servers will usually
+ * want to use \c mbedtls_ssl_conf_psk_cb() instead.
+ *
+ * \note An opaque PSK set by \c mbedtls_ssl_set_hs_psk_opaque() in
+ * the PSK callback takes precedence over an opaque PSK
+ * configured by this function.
+ *
+ * \param conf The SSL configuration to register the PSK with.
+ * \param psk The identifier of the key slot holding the PSK.
+ * Until \p conf is destroyed or this function is successfully
+ * called again, the key slot \p psk must be populated with a
+ * key of type PSA_ALG_CATEGORY_KEY_DERIVATION whose policy
+ * allows its use for the key derivation algorithm applied
+ * in the handshake.
+ * \param psk_identity The pointer to the pre-shared key identity.
+ * \param psk_identity_len The length of the pre-shared key identity
+ * in bytes.
+ *
+ * \note The PSK identity hint is copied internally and hence need
+ * not be preserved by the caller for the lifetime of the
+ * SSL configuration.
+ *
+ * \return \c 0 if successful.
+ * \return #MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE if no more PSKs
+ * can be configured. In this case, the old PSK(s) remain intact.
+ * \return Another negative error code on other kinds of failure.
+ */
+int mbedtls_ssl_conf_psk_opaque(mbedtls_ssl_config *conf,
+ mbedtls_svc_key_id_t psk,
+ const unsigned char *psk_identity,
+ size_t psk_identity_len);
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
+/**
+ * \brief Set the pre-shared Key (PSK) for the current handshake.
+ *
+ * \note This should only be called inside the PSK callback,
+ * i.e. the function passed to \c mbedtls_ssl_conf_psk_cb().
+ *
+ * \note A PSK set by this function takes precedence over a PSK
+ * configured by \c mbedtls_ssl_conf_psk().
+ *
+ * \param ssl The SSL context to configure a PSK for.
+ * \param psk The pointer to the pre-shared key.
+ * \param psk_len The length of the pre-shared key in bytes.
+ *
+ * \return \c 0 if successful.
+ * \return An \c MBEDTLS_ERR_SSL_XXX error code on failure.
+ */
+int mbedtls_ssl_set_hs_psk(mbedtls_ssl_context *ssl,
+ const unsigned char *psk, size_t psk_len);
+
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+/**
+ * \brief Set an opaque pre-shared Key (PSK) for the current handshake.
+ *
+ * \note This should only be called inside the PSK callback,
+ * i.e. the function passed to \c mbedtls_ssl_conf_psk_cb().
+ *
+ * \note An opaque PSK set by this function takes precedence over an
+ * opaque PSK configured by \c mbedtls_ssl_conf_psk_opaque().
+ *
+ * \param ssl The SSL context to configure a PSK for.
+ * \param psk The identifier of the key slot holding the PSK.
+ * For the duration of the current handshake, the key slot
+ * must be populated with a key of type
+ * PSA_ALG_CATEGORY_KEY_DERIVATION whose policy allows its
+ * use for the key derivation algorithm
+ * applied in the handshake.
+ *
+ * \return \c 0 if successful.
+ * \return An \c MBEDTLS_ERR_SSL_XXX error code on failure.
+ */
+int mbedtls_ssl_set_hs_psk_opaque(mbedtls_ssl_context *ssl,
+ mbedtls_svc_key_id_t psk);
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
+#if defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Set the PSK callback (server-side only).
+ *
+ * If set, the PSK callback is called for each
+ * handshake where a PSK-based ciphersuite was negotiated.
+ * The caller provides the identity received and wants to
+ * receive the actual PSK data and length.
+ *
+ * The callback has the following parameters:
+ * - \c void*: The opaque pointer \p p_psk.
+ * - \c mbedtls_ssl_context*: The SSL context to which
+ * the operation applies.
+ * - \c const unsigned char*: The PSK identity
+ * selected by the client.
+ * - \c size_t: The length of the PSK identity
+ * selected by the client.
+ *
+ * If a valid PSK identity is found, the callback should use
+ * \c mbedtls_ssl_set_hs_psk() or
+ * \c mbedtls_ssl_set_hs_psk_opaque()
+ * on the SSL context to set the correct PSK and return \c 0.
+ * Any other return value will result in a denied PSK identity.
+ *
+ * \note A dynamic PSK (i.e. set by the PSK callback) takes
+ * precedence over a static PSK (i.e. set by
+ * \c mbedtls_ssl_conf_psk() or
+ * \c mbedtls_ssl_conf_psk_opaque()).
+ * This means that if you set a PSK callback using this
+ * function, you don't need to set a PSK using
+ * \c mbedtls_ssl_conf_psk() or
+ * \c mbedtls_ssl_conf_psk_opaque()).
+ *
+ * \param conf The SSL configuration to register the callback with.
+ * \param f_psk The callback for selecting and setting the PSK based
+ * in the PSK identity chosen by the client.
+ * \param p_psk A pointer to an opaque structure to be passed to
+ * the callback, for example a PSK store.
+ */
+void mbedtls_ssl_conf_psk_cb(mbedtls_ssl_config *conf,
+ int (*f_psk)(void *, mbedtls_ssl_context *, const unsigned char *,
+ size_t),
+ void *p_psk);
+#endif /* MBEDTLS_SSL_SRV_C */
+#endif /* MBEDTLS_SSL_HANDSHAKE_WITH_PSK_ENABLED */
+
+#if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Set the Diffie-Hellman public P and G values
+ * from big-endian binary presentations.
+ * (Default values: MBEDTLS_DHM_RFC3526_MODP_2048_[PG]_BIN)
+ *
+ * \param conf SSL configuration
+ * \param dhm_P Diffie-Hellman-Merkle modulus in big-endian binary form
+ * \param P_len Length of DHM modulus
+ * \param dhm_G Diffie-Hellman-Merkle generator in big-endian binary form
+ * \param G_len Length of DHM generator
+ *
+ * \return 0 if successful
+ */
+int mbedtls_ssl_conf_dh_param_bin(mbedtls_ssl_config *conf,
+ const unsigned char *dhm_P, size_t P_len,
+ const unsigned char *dhm_G, size_t G_len);
+
+/**
+ * \brief Set the Diffie-Hellman public P and G values,
+ * read from existing context (server-side only)
+ *
+ * \param conf SSL configuration
+ * \param dhm_ctx Diffie-Hellman-Merkle context
+ *
+ * \return 0 if successful
+ */
+int mbedtls_ssl_conf_dh_param_ctx(mbedtls_ssl_config *conf, mbedtls_dhm_context *dhm_ctx);
+#endif /* MBEDTLS_DHM_C && defined(MBEDTLS_SSL_SRV_C) */
+
+#if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
+/**
+ * \brief Set the minimum length for Diffie-Hellman parameters.
+ * (Client-side only.)
+ * (Default: 1024 bits.)
+ *
+ * \param conf SSL configuration
+ * \param bitlen Minimum bit length of the DHM prime
+ */
+void mbedtls_ssl_conf_dhm_min_bitlen(mbedtls_ssl_config *conf,
+ unsigned int bitlen);
+#endif /* MBEDTLS_DHM_C && MBEDTLS_SSL_CLI_C */
+
+#if defined(MBEDTLS_ECP_C)
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+/**
+ * \brief Set the allowed curves in order of preference.
+ *
+ * On server: this only affects selection of the ECDHE curve;
+ * the curves used for ECDH and ECDSA are determined by the
+ * list of available certificates instead.
+ *
+ * On client: this affects the list of curves offered for any
+ * use. The server can override our preference order.
+ *
+ * Both sides: limits the set of curves accepted for use in
+ * ECDHE and in the peer's end-entity certificate.
+ *
+ * \deprecated Superseded by mbedtls_ssl_conf_groups().
+ *
+ * \note This has no influence on which curves are allowed inside the
+ * certificate chains, see \c mbedtls_ssl_conf_cert_profile()
+ * for that. For the end-entity certificate however, the key
+ * will be accepted only if it is allowed both by this list
+ * and by the cert profile.
+ *
+ * \note This list should be ordered by decreasing preference
+ * (preferred curve first).
+ *
+ * \note The default list is the same set of curves that
+ * #mbedtls_x509_crt_profile_default allows, plus
+ * ECDHE-only curves selected according to the same criteria.
+ * The order favors curves with the lowest resource usage.
+ *
+ * \note New minor versions of Mbed TLS may extend this list,
+ * for example if new curves are added to the library.
+ * New minor versions of Mbed TLS will not remove items
+ * from this list unless serious security concerns require it.
+ * New minor versions of Mbed TLS may change the order in
+ * keeping with the general principle of favoring the lowest
+ * resource usage.
+ *
+ * \param conf SSL configuration
+ * \param curves Ordered list of allowed curves,
+ * terminated by MBEDTLS_ECP_DP_NONE.
+ */
+void MBEDTLS_DEPRECATED mbedtls_ssl_conf_curves(mbedtls_ssl_config *conf,
+ const mbedtls_ecp_group_id *curves);
+#endif /* MBEDTLS_DEPRECATED_REMOVED */
+#endif /* MBEDTLS_ECP_C */
+
+/**
+ * \brief Set the allowed groups in order of preference.
+ *
+ * On server: This only affects the choice of key agreement mechanism
+ *
+ * On client: this affects the list of groups offered for any
+ * use. The server can override our preference order.
+ *
+ * Both sides: limits the set of groups accepted for use in
+ * key sharing.
+ *
+ * \note This function replaces the deprecated mbedtls_ssl_conf_curves(),
+ * which only allows ECP curves to be configured.
+ *
+ * \note The most recent invocation of either mbedtls_ssl_conf_curves()
+ * or mbedtls_ssl_conf_groups() nullifies all previous invocations
+ * of both.
+ *
+ * \note This list should be ordered by decreasing preference
+ * (preferred group first).
+ *
+ * \note When this function is not called, a default list is used,
+ * consisting of all supported curves at 255 bits and above,
+ * and all supported finite fields at 2048 bits and above.
+ * The order favors groups with the lowest resource usage.
+ *
+ * \note New minor versions of Mbed TLS will not remove items
+ * from the default list unless serious security concerns require it.
+ * New minor versions of Mbed TLS may change the order in
+ * keeping with the general principle of favoring the lowest
+ * resource usage.
+ *
+ * \param conf SSL configuration
+ * \param groups List of allowed groups ordered by preference, terminated by 0.
+ * Must contain valid IANA NamedGroup IDs (provided via either an integer
+ * or using MBEDTLS_TLS1_3_NAMED_GROUP_XXX macros).
+ */
+void mbedtls_ssl_conf_groups(mbedtls_ssl_config *conf,
+ const uint16_t *groups);
+
+#if defined(MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED)
+#if !defined(MBEDTLS_DEPRECATED_REMOVED) && defined(MBEDTLS_SSL_PROTO_TLS1_2)
+/**
+ * \brief Set the allowed hashes for signatures during the handshake.
+ *
+ * \note This only affects which hashes are offered and can be used
+ * for signatures during the handshake. Hashes for message
+ * authentication and the TLS PRF are controlled by the
+ * ciphersuite, see \c mbedtls_ssl_conf_ciphersuites(). Hashes
+ * used for certificate signature are controlled by the
+ * verification profile, see \c mbedtls_ssl_conf_cert_profile().
+ *
+ * \note This list should be ordered by decreasing preference
+ * (preferred hash first).
+ *
+ * \note By default, all supported hashes whose length is at least
+ * 256 bits are allowed. This is the same set as the default
+ * for certificate verification
+ * (#mbedtls_x509_crt_profile_default).
+ * The preference order is currently unspecified and may
+ * change in future versions.
+ *
+ * \note New minor versions of Mbed TLS may extend this list,
+ * for example if new curves are added to the library.
+ * New minor versions of Mbed TLS will not remove items
+ * from this list unless serious security concerns require it.
+ *
+ * \param conf SSL configuration
+ * \param hashes Ordered list of allowed signature hashes,
+ * terminated by \c MBEDTLS_MD_NONE.
+ */
+void MBEDTLS_DEPRECATED mbedtls_ssl_conf_sig_hashes(mbedtls_ssl_config *conf,
+ const int *hashes);
+#endif /* !MBEDTLS_DEPRECATED_REMOVED && MBEDTLS_SSL_PROTO_TLS1_2 */
+
+/**
+ * \brief Configure allowed signature algorithms for use in TLS 1.3
+ *
+ * \param conf The SSL configuration to use.
+ * \param sig_algs List of allowed IANA values for TLS 1.3 signature algorithms,
+ * terminated by \c MBEDTLS_TLS1_3_SIG_NONE. The list must remain
+ * available throughout the lifetime of the conf object. Supported
+ * values are available as \c MBEDTLS_TLS1_3_SIG_XXXX
+ */
+void mbedtls_ssl_conf_sig_algs(mbedtls_ssl_config *conf,
+ const uint16_t *sig_algs);
+#endif /* MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED */
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+/**
+ * \brief Set or reset the hostname to check against the received
+ * server certificate. It sets the ServerName TLS extension,
+ * too, if that extension is enabled. (client-side only)
+ *
+ * \param ssl SSL context
+ * \param hostname the server hostname, may be NULL to clear hostname
+
+ * \note Maximum hostname length MBEDTLS_SSL_MAX_HOST_NAME_LEN.
+ *
+ * \return 0 if successful, MBEDTLS_ERR_SSL_ALLOC_FAILED on
+ * allocation failure, MBEDTLS_ERR_SSL_BAD_INPUT_DATA on
+ * too long input hostname.
+ *
+ * Hostname set to the one provided on success (cleared
+ * when NULL). On allocation failure hostname is cleared.
+ * On too long input failure, old hostname is unchanged.
+ */
+int mbedtls_ssl_set_hostname(mbedtls_ssl_context *ssl, const char *hostname);
+
+/**
+ * \brief Get the hostname that checked against the received
+ * server certificate. It is used to set the ServerName
+ * TLS extension, too, if that extension is enabled.
+ * (client-side only)
+ *
+ * \param ssl SSL context
+ *
+ * \return const pointer to the hostname value
+ */
+static inline const char *mbedtls_ssl_get_hostname(mbedtls_ssl_context *ssl)
+{
+ return ssl->MBEDTLS_PRIVATE(hostname);
+}
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
+/**
+ * \brief Retrieve SNI extension value for the current handshake.
+ * Available in \c f_cert_cb of \c mbedtls_ssl_conf_cert_cb(),
+ * this is the same value passed to \c f_sni callback of
+ * \c mbedtls_ssl_conf_sni() and may be used instead of
+ * \c mbedtls_ssl_conf_sni().
+ *
+ * \param ssl SSL context
+ * \param name_len pointer into which to store length of returned value.
+ * 0 if SNI extension is not present or not yet processed.
+ *
+ * \return const pointer to SNI extension value.
+ * - value is valid only when called in \c f_cert_cb
+ * registered with \c mbedtls_ssl_conf_cert_cb().
+ * - value is NULL if SNI extension is not present.
+ * - value is not '\0'-terminated. Use \c name_len for len.
+ * - value must not be freed.
+ */
+const unsigned char *mbedtls_ssl_get_hs_sni(mbedtls_ssl_context *ssl,
+ size_t *name_len);
+
+/**
+ * \brief Set own certificate and key for the current handshake
+ *
+ * \note Same as \c mbedtls_ssl_conf_own_cert() but for use within
+ * the SNI callback or the certificate selection callback.
+ *
+ * \note Passing null \c own_cert clears the certificate list for
+ * the current handshake.
+ *
+ * \param ssl SSL context
+ * \param own_cert own public certificate chain
+ * \param pk_key own private key
+ *
+ * \return 0 on success or MBEDTLS_ERR_SSL_ALLOC_FAILED
+ */
+int mbedtls_ssl_set_hs_own_cert(mbedtls_ssl_context *ssl,
+ mbedtls_x509_crt *own_cert,
+ mbedtls_pk_context *pk_key);
+
+/**
+ * \brief Set the data required to verify peer certificate for the
+ * current handshake
+ *
+ * \note Same as \c mbedtls_ssl_conf_ca_chain() but for use within
+ * the SNI callback or the certificate selection callback.
+ *
+ * \param ssl SSL context
+ * \param ca_chain trusted CA chain (meaning all fully trusted top-level CAs)
+ * \param ca_crl trusted CA CRLs
+ */
+void mbedtls_ssl_set_hs_ca_chain(mbedtls_ssl_context *ssl,
+ mbedtls_x509_crt *ca_chain,
+ mbedtls_x509_crl *ca_crl);
+
+#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+/**
+ * \brief Set DN hints sent to client in CertificateRequest message
+ *
+ * \note Same as \c mbedtls_ssl_conf_dn_hints() but for use within
+ * the SNI callback or the certificate selection callback.
+ *
+ * \param ssl SSL context
+ * \param crt crt chain whose subject DNs are issuer DNs of client certs
+ * from which the client should select client peer certificate.
+ */
+void mbedtls_ssl_set_hs_dn_hints(mbedtls_ssl_context *ssl,
+ const mbedtls_x509_crt *crt);
+#endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
+
+/**
+ * \brief Set authmode for the current handshake.
+ *
+ * \note Same as \c mbedtls_ssl_conf_authmode() but for use within
+ * the SNI callback or the certificate selection callback.
+ *
+ * \param ssl SSL context
+ * \param authmode MBEDTLS_SSL_VERIFY_NONE, MBEDTLS_SSL_VERIFY_OPTIONAL or
+ * MBEDTLS_SSL_VERIFY_REQUIRED
+ */
+void mbedtls_ssl_set_hs_authmode(mbedtls_ssl_context *ssl,
+ int authmode);
+
+/**
+ * \brief Set server side ServerName TLS extension callback
+ * (optional, server-side only).
+ *
+ * If set, the ServerName callback is called whenever the
+ * server receives a ServerName TLS extension from the client
+ * during a handshake. The ServerName callback has the
+ * following parameters: (void *parameter, mbedtls_ssl_context *ssl,
+ * const unsigned char *hostname, size_t len). If a suitable
+ * certificate is found, the callback must set the
+ * certificate(s) and key(s) to use with \c
+ * mbedtls_ssl_set_hs_own_cert() (can be called repeatedly),
+ * and may optionally adjust the CA and associated CRL with \c
+ * mbedtls_ssl_set_hs_ca_chain() as well as the client
+ * authentication mode with \c mbedtls_ssl_set_hs_authmode(),
+ * then must return 0. If no matching name is found, the
+ * callback may return non-zero to abort the handshake.
+ *
+ * \param conf SSL configuration
+ * \param f_sni verification function
+ * \param p_sni verification parameter
+ */
+void mbedtls_ssl_conf_sni(mbedtls_ssl_config *conf,
+ int (*f_sni)(void *, mbedtls_ssl_context *, const unsigned char *,
+ size_t),
+ void *p_sni);
+#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
+
+#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+/**
+ * \brief Set the EC J-PAKE password for current handshake.
+ *
+ * \note An internal copy is made, and destroyed as soon as the
+ * handshake is completed, or when the SSL context is reset or
+ * freed.
+ *
+ * \note The SSL context needs to be already set up. The right place
+ * to call this function is between \c mbedtls_ssl_setup() or
+ * \c mbedtls_ssl_reset() and \c mbedtls_ssl_handshake().
+ * Password cannot be empty (see RFC 8236).
+ *
+ * \param ssl SSL context
+ * \param pw EC J-PAKE password (pre-shared secret). It cannot be empty
+ * \param pw_len length of pw in bytes
+ *
+ * \return 0 on success, or a negative error code.
+ */
+int mbedtls_ssl_set_hs_ecjpake_password(mbedtls_ssl_context *ssl,
+ const unsigned char *pw,
+ size_t pw_len);
+
+/**
+ * \brief Set the EC J-PAKE opaque password for current handshake.
+ *
+ * \note The key must remain valid until the handshake is over.
+ *
+ * \note The SSL context needs to be already set up. The right place
+ * to call this function is between \c mbedtls_ssl_setup() or
+ * \c mbedtls_ssl_reset() and \c mbedtls_ssl_handshake().
+ *
+ * \param ssl SSL context
+ * \param pwd EC J-PAKE opaque password
+ *
+ * \return 0 on success, or a negative error code.
+ */
+int mbedtls_ssl_set_hs_ecjpake_password_opaque(mbedtls_ssl_context *ssl,
+ mbedtls_svc_key_id_t pwd);
+#endif /*MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
+
+#if defined(MBEDTLS_SSL_ALPN)
+/**
+ * \brief Set the supported Application Layer Protocols.
+ *
+ * \param conf SSL configuration
+ * \param protos Pointer to a NULL-terminated list of supported protocols,
+ * in decreasing preference order. The pointer to the list is
+ * recorded by the library for later reference as required, so
+ * the lifetime of the table must be at least as long as the
+ * lifetime of the SSL configuration structure.
+ *
+ * \return 0 on success, or MBEDTLS_ERR_SSL_BAD_INPUT_DATA.
+ */
+int mbedtls_ssl_conf_alpn_protocols(mbedtls_ssl_config *conf, const char **protos);
+
+/**
+ * \brief Get the name of the negotiated Application Layer Protocol.
+ * This function should be called after the handshake is
+ * completed.
+ *
+ * \param ssl SSL context
+ *
+ * \return Protocol name, or NULL if no protocol was negotiated.
+ */
+const char *mbedtls_ssl_get_alpn_protocol(const mbedtls_ssl_context *ssl);
+#endif /* MBEDTLS_SSL_ALPN */
+
+#if defined(MBEDTLS_SSL_DTLS_SRTP)
+#if defined(MBEDTLS_DEBUG_C)
+static inline const char *mbedtls_ssl_get_srtp_profile_as_string(mbedtls_ssl_srtp_profile profile)
+{
+ switch (profile) {
+ case MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_80:
+ return "MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_80";
+ case MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_32:
+ return "MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_32";
+ case MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_80:
+ return "MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_80";
+ case MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_32:
+ return "MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_32";
+ default: break;
+ }
+ return "";
+}
+#endif /* MBEDTLS_DEBUG_C */
+/**
+ * \brief Manage support for mki(master key id) value
+ * in use_srtp extension.
+ * MKI is an optional part of SRTP used for key management
+ * and re-keying. See RFC3711 section 3.1 for details.
+ * The default value is
+ * #MBEDTLS_SSL_DTLS_SRTP_MKI_UNSUPPORTED.
+ *
+ * \param conf The SSL configuration to manage mki support.
+ * \param support_mki_value Enable or disable mki usage. Values are
+ * #MBEDTLS_SSL_DTLS_SRTP_MKI_UNSUPPORTED
+ * or #MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED.
+ */
+void mbedtls_ssl_conf_srtp_mki_value_supported(mbedtls_ssl_config *conf,
+ int support_mki_value);
+
+/**
+ * \brief Set the supported DTLS-SRTP protection profiles.
+ *
+ * \param conf SSL configuration
+ * \param profiles Pointer to a List of MBEDTLS_TLS_SRTP_UNSET terminated
+ * supported protection profiles
+ * in decreasing preference order.
+ * The pointer to the list is recorded by the library
+ * for later reference as required, so the lifetime
+ * of the table must be at least as long as the lifetime
+ * of the SSL configuration structure.
+ * The list must not hold more than
+ * MBEDTLS_TLS_SRTP_MAX_PROFILE_LIST_LENGTH elements
+ * (excluding the terminating MBEDTLS_TLS_SRTP_UNSET).
+ *
+ * \return 0 on success
+ * \return #MBEDTLS_ERR_SSL_BAD_INPUT_DATA when the list of
+ * protection profiles is incorrect.
+ */
+int mbedtls_ssl_conf_dtls_srtp_protection_profiles
+ (mbedtls_ssl_config *conf,
+ const mbedtls_ssl_srtp_profile *profiles);
+
+/**
+ * \brief Set the mki_value for the current DTLS-SRTP session.
+ *
+ * \param ssl SSL context to use.
+ * \param mki_value The MKI value to set.
+ * \param mki_len The length of the MKI value.
+ *
+ * \note This function is relevant on client side only.
+ * The server discovers the mki value during handshake.
+ * A mki value set on server side using this function
+ * is ignored.
+ *
+ * \return 0 on success
+ * \return #MBEDTLS_ERR_SSL_BAD_INPUT_DATA
+ * \return #MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE
+ */
+int mbedtls_ssl_dtls_srtp_set_mki_value(mbedtls_ssl_context *ssl,
+ unsigned char *mki_value,
+ uint16_t mki_len);
+/**
+ * \brief Get the negotiated DTLS-SRTP information:
+ * Protection profile and MKI value.
+ *
+ * \warning This function must be called after the handshake is
+ * completed. The value returned by this function must
+ * not be trusted or acted upon before the handshake completes.
+ *
+ * \param ssl The SSL context to query.
+ * \param dtls_srtp_info The negotiated DTLS-SRTP information:
+ * - Protection profile in use.
+ * A direct mapping of the iana defined value for protection
+ * profile on an uint16_t.
+ http://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml
+ * #MBEDTLS_TLS_SRTP_UNSET if the use of SRTP was not negotiated
+ * or peer's Hello packet was not parsed yet.
+ * - mki size and value( if size is > 0 ).
+ */
+void mbedtls_ssl_get_dtls_srtp_negotiation_result(const mbedtls_ssl_context *ssl,
+ mbedtls_dtls_srtp_info *dtls_srtp_info);
+#endif /* MBEDTLS_SSL_DTLS_SRTP */
+
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+/**
+ * \brief Set the maximum supported version sent from the client side
+ * and/or accepted at the server side.
+ *
+ * See also the documentation of mbedtls_ssl_conf_min_version().
+ *
+ * \note This ignores ciphersuites from higher versions.
+ *
+ * \note This function is deprecated and has been replaced by
+ * \c mbedtls_ssl_conf_max_tls_version().
+ *
+ * \param conf SSL configuration
+ * \param major Major version number (#MBEDTLS_SSL_MAJOR_VERSION_3)
+ * \param minor Minor version number
+ * (#MBEDTLS_SSL_MINOR_VERSION_3 for (D)TLS 1.2,
+ * #MBEDTLS_SSL_MINOR_VERSION_4 for TLS 1.3)
+ */
+void MBEDTLS_DEPRECATED mbedtls_ssl_conf_max_version(mbedtls_ssl_config *conf, int major,
+ int minor);
+#endif /* MBEDTLS_DEPRECATED_REMOVED */
+
+/**
+ * \brief Set the maximum supported version sent from the client side
+ * and/or accepted at the server side.
+ *
+ * \note After the handshake, you can call
+ * mbedtls_ssl_get_version_number() to see what version was
+ * negotiated.
+ *
+ * \param conf SSL configuration
+ * \param tls_version TLS protocol version number (\c mbedtls_ssl_protocol_version)
+ * (#MBEDTLS_SSL_VERSION_UNKNOWN is not valid)
+ */
+static inline void mbedtls_ssl_conf_max_tls_version(mbedtls_ssl_config *conf,
+ mbedtls_ssl_protocol_version tls_version)
+{
+ conf->MBEDTLS_PRIVATE(max_tls_version) = tls_version;
+}
+
+#if !defined(MBEDTLS_DEPRECATED_REMOVED)
+/**
+ * \brief Set the minimum accepted SSL/TLS protocol version
+ *
+ * \note By default, all supported versions are accepted.
+ * Future versions of the library may disable older
+ * protocol versions by default if they become deprecated.
+ *
+ * \note The following versions are supported (if enabled at
+ * compile time):
+ * - (D)TLS 1.2: \p major = #MBEDTLS_SSL_MAJOR_VERSION_3,
+ * \p minor = #MBEDTLS_SSL_MINOR_VERSION_3
+ * - TLS 1.3: \p major = #MBEDTLS_SSL_MAJOR_VERSION_3,
+ * \p minor = #MBEDTLS_SSL_MINOR_VERSION_4
+ *
+ * Note that the numbers in the constant names are the
+ * TLS internal protocol numbers, and the minor versions
+ * differ by one from the human-readable versions!
+ *
+ * \note Input outside of the SSL_MAX_XXXXX_VERSION and
+ * SSL_MIN_XXXXX_VERSION range is ignored.
+ *
+ * \note After the handshake, you can call
+ * mbedtls_ssl_get_version_number() to see what version was
+ * negotiated.
+ *
+ * \note This function is deprecated and has been replaced by
+ * \c mbedtls_ssl_conf_min_tls_version().
+ *
+ * \param conf SSL configuration
+ * \param major Major version number (#MBEDTLS_SSL_MAJOR_VERSION_3)
+ * \param minor Minor version number
+ * (#MBEDTLS_SSL_MINOR_VERSION_3 for (D)TLS 1.2,
+ * #MBEDTLS_SSL_MINOR_VERSION_4 for TLS 1.3)
+ */
+void MBEDTLS_DEPRECATED mbedtls_ssl_conf_min_version(mbedtls_ssl_config *conf, int major,
+ int minor);
+#endif /* MBEDTLS_DEPRECATED_REMOVED */
+
+/**
+ * \brief Set the minimum supported version sent from the client side
+ * and/or accepted at the server side.
+ *
+ * \note After the handshake, you can call
+ * mbedtls_ssl_get_version_number() to see what version was
+ * negotiated.
+ *
+ * \param conf SSL configuration
+ * \param tls_version TLS protocol version number (\c mbedtls_ssl_protocol_version)
+ * (#MBEDTLS_SSL_VERSION_UNKNOWN is not valid)
+ */
+static inline void mbedtls_ssl_conf_min_tls_version(mbedtls_ssl_config *conf,
+ mbedtls_ssl_protocol_version tls_version)
+{
+ conf->MBEDTLS_PRIVATE(min_tls_version) = tls_version;
+}
+
+#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
+/**
+ * \brief Enable or disable Encrypt-then-MAC
+ * (Default: MBEDTLS_SSL_ETM_ENABLED)
+ *
+ * \note This should always be enabled, it is a security
+ * improvement, and should not cause any interoperability
+ * issue (used only if the peer supports it too).
+ *
+ * \param conf SSL configuration
+ * \param etm MBEDTLS_SSL_ETM_ENABLED or MBEDTLS_SSL_ETM_DISABLED
+ */
+void mbedtls_ssl_conf_encrypt_then_mac(mbedtls_ssl_config *conf, char etm);
+#endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
+
+#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
+/**
+ * \brief Enable or disable Extended Master Secret negotiation.
+ * (Default: MBEDTLS_SSL_EXTENDED_MS_ENABLED)
+ *
+ * \note This should always be enabled, it is a security fix to the
+ * protocol, and should not cause any interoperability issue
+ * (used only if the peer supports it too).
+ *
+ * \param conf SSL configuration
+ * \param ems MBEDTLS_SSL_EXTENDED_MS_ENABLED or MBEDTLS_SSL_EXTENDED_MS_DISABLED
+ */
+void mbedtls_ssl_conf_extended_master_secret(mbedtls_ssl_config *conf, char ems);
+#endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
+
+#if defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Whether to send a list of acceptable CAs in
+ * CertificateRequest messages.
+ * (Default: do send)
+ *
+ * \param conf SSL configuration
+ * \param cert_req_ca_list MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED or
+ * MBEDTLS_SSL_CERT_REQ_CA_LIST_DISABLED
+ */
+void mbedtls_ssl_conf_cert_req_ca_list(mbedtls_ssl_config *conf,
+ char cert_req_ca_list);
+#endif /* MBEDTLS_SSL_SRV_C */
+
+#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
+/**
+ * \brief Set the maximum fragment length to emit and/or negotiate.
+ * (Typical: the smaller of #MBEDTLS_SSL_IN_CONTENT_LEN and
+ * #MBEDTLS_SSL_OUT_CONTENT_LEN, usually `2^14` bytes)
+ * (Server: set maximum fragment length to emit,
+ * usually negotiated by the client during handshake)
+ * (Client: set maximum fragment length to emit *and*
+ * negotiate with the server during handshake)
+ * (Default: #MBEDTLS_SSL_MAX_FRAG_LEN_NONE)
+ *
+ * \note On the client side, the maximum fragment length extension
+ * *will not* be used, unless the maximum fragment length has
+ * been set via this function to a value different than
+ * #MBEDTLS_SSL_MAX_FRAG_LEN_NONE.
+ *
+ * \note With TLS, this currently only affects ApplicationData (sent
+ * with \c mbedtls_ssl_read()), not handshake messages.
+ * With DTLS, this affects both ApplicationData and handshake.
+ *
+ * \note This sets the maximum length for a record's payload,
+ * excluding record overhead that will be added to it, see
+ * \c mbedtls_ssl_get_record_expansion().
+ *
+ * \note For DTLS, it is also possible to set a limit for the total
+ * size of datagrams passed to the transport layer, including
+ * record overhead, see \c mbedtls_ssl_set_mtu().
+ *
+ * \param conf SSL configuration
+ * \param mfl_code Code for maximum fragment length (allowed values:
+ * MBEDTLS_SSL_MAX_FRAG_LEN_512, MBEDTLS_SSL_MAX_FRAG_LEN_1024,
+ * MBEDTLS_SSL_MAX_FRAG_LEN_2048, MBEDTLS_SSL_MAX_FRAG_LEN_4096)
+ *
+ * \return 0 if successful or MBEDTLS_ERR_SSL_BAD_INPUT_DATA
+ */
+int mbedtls_ssl_conf_max_frag_len(mbedtls_ssl_config *conf, unsigned char mfl_code);
+#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
+
+#if defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Pick the ciphersuites order according to the second parameter
+ * in the SSL Server module (MBEDTLS_SSL_SRV_C).
+ * (Default, if never called: MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_SERVER)
+ *
+ * \param conf SSL configuration
+ * \param order Server or client (MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_SERVER
+ * or MBEDTLS_SSL_SRV_CIPHERSUITE_ORDER_CLIENT)
+ */
+void mbedtls_ssl_conf_preference_order(mbedtls_ssl_config *conf, int order);
+#endif /* MBEDTLS_SSL_SRV_C */
+
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
+ defined(MBEDTLS_SSL_CLI_C)
+/**
+ * \brief Enable / Disable session tickets (client only).
+ * (Default: MBEDTLS_SSL_SESSION_TICKETS_ENABLED.)
+ *
+ * \note On server, use \c mbedtls_ssl_conf_session_tickets_cb().
+ *
+ * \param conf SSL configuration
+ * \param use_tickets Enable or disable (MBEDTLS_SSL_SESSION_TICKETS_ENABLED or
+ * MBEDTLS_SSL_SESSION_TICKETS_DISABLED)
+ */
+void mbedtls_ssl_conf_session_tickets(mbedtls_ssl_config *conf, int use_tickets);
+#endif /* MBEDTLS_SSL_SESSION_TICKETS &&
+ MBEDTLS_SSL_CLI_C */
+
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
+ defined(MBEDTLS_SSL_SRV_C) && \
+ defined(MBEDTLS_SSL_PROTO_TLS1_3)
+/**
+ * \brief Number of NewSessionTicket messages for the server to send
+ * after handshake completion.
+ *
+ * \note The default value is
+ * \c MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS.
+ *
+ * \note In case of a session resumption, this setting only partially apply.
+ * At most one ticket is sent in that case to just renew the pool of
+ * tickets of the client. The rationale is to avoid the number of
+ * tickets on the server to become rapidly out of control when the
+ * server has the same configuration for all its connection instances.
+ *
+ * \param conf SSL configuration
+ * \param num_tickets Number of NewSessionTicket.
+ *
+ */
+void mbedtls_ssl_conf_new_session_tickets(mbedtls_ssl_config *conf,
+ uint16_t num_tickets);
+#endif /* MBEDTLS_SSL_SESSION_TICKETS &&
+ MBEDTLS_SSL_SRV_C &&
+ MBEDTLS_SSL_PROTO_TLS1_3*/
+
+#if defined(MBEDTLS_SSL_RENEGOTIATION)
+/**
+ * \brief Enable / Disable renegotiation support for connection when
+ * initiated by peer
+ * (Default: MBEDTLS_SSL_RENEGOTIATION_DISABLED)
+ *
+ * \warning It is recommended to always disable renegotiation unless you
+ * know you need it and you know what you're doing. In the
+ * past, there have been several issues associated with
+ * renegotiation or a poor understanding of its properties.
+ *
+ * \note Server-side, enabling renegotiation also makes the server
+ * susceptible to a resource DoS by a malicious client.
+ *
+ * \param conf SSL configuration
+ * \param renegotiation Enable or disable (MBEDTLS_SSL_RENEGOTIATION_ENABLED or
+ * MBEDTLS_SSL_RENEGOTIATION_DISABLED)
+ */
+void mbedtls_ssl_conf_renegotiation(mbedtls_ssl_config *conf, int renegotiation);
+#endif /* MBEDTLS_SSL_RENEGOTIATION */
+
+/**
+ * \brief Prevent or allow legacy renegotiation.
+ * (Default: MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION)
+ *
+ * MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION allows connections to
+ * be established even if the peer does not support
+ * secure renegotiation, but does not allow renegotiation
+ * to take place if not secure.
+ * (Interoperable and secure option)
+ *
+ * MBEDTLS_SSL_LEGACY_ALLOW_RENEGOTIATION allows renegotiations
+ * with non-upgraded peers. Allowing legacy renegotiation
+ * makes the connection vulnerable to specific man in the
+ * middle attacks. (See RFC 5746)
+ * (Most interoperable and least secure option)
+ *
+ * MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE breaks off connections
+ * if peer does not support secure renegotiation. Results
+ * in interoperability issues with non-upgraded peers
+ * that do not support renegotiation altogether.
+ * (Most secure option, interoperability issues)
+ *
+ * \param conf SSL configuration
+ * \param allow_legacy Prevent or allow (SSL_NO_LEGACY_RENEGOTIATION,
+ * SSL_ALLOW_LEGACY_RENEGOTIATION or
+ * MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE)
+ */
+void mbedtls_ssl_conf_legacy_renegotiation(mbedtls_ssl_config *conf, int allow_legacy);
+
+#if defined(MBEDTLS_SSL_RENEGOTIATION)
+/**
+ * \brief Enforce renegotiation requests.
+ * (Default: enforced, max_records = 16)
+ *
+ * When we request a renegotiation, the peer can comply or
+ * ignore the request. This function allows us to decide
+ * whether to enforce our renegotiation requests by closing
+ * the connection if the peer doesn't comply.
+ *
+ * However, records could already be in transit from the peer
+ * when the request is emitted. In order to increase
+ * reliability, we can accept a number of records before the
+ * expected handshake records.
+ *
+ * The optimal value is highly dependent on the specific usage
+ * scenario.
+ *
+ * \note With DTLS and server-initiated renegotiation, the
+ * HelloRequest is retransmitted every time mbedtls_ssl_read() times
+ * out or receives Application Data, until:
+ * - max_records records have beens seen, if it is >= 0, or
+ * - the number of retransmits that would happen during an
+ * actual handshake has been reached.
+ * Please remember the request might be lost a few times
+ * if you consider setting max_records to a really low value.
+ *
+ * \warning On client, the grace period can only happen during
+ * mbedtls_ssl_read(), as opposed to mbedtls_ssl_write() and mbedtls_ssl_renegotiate()
+ * which always behave as if max_record was 0. The reason is,
+ * if we receive application data from the server, we need a
+ * place to write it, which only happens during mbedtls_ssl_read().
+ *
+ * \param conf SSL configuration
+ * \param max_records Use MBEDTLS_SSL_RENEGOTIATION_NOT_ENFORCED if you don't want to
+ * enforce renegotiation, or a non-negative value to enforce
+ * it but allow for a grace period of max_records records.
+ */
+void mbedtls_ssl_conf_renegotiation_enforced(mbedtls_ssl_config *conf, int max_records);
+
+/**
+ * \brief Set record counter threshold for periodic renegotiation.
+ * (Default: 2^48 - 1)
+ *
+ * Renegotiation is automatically triggered when a record
+ * counter (outgoing or incoming) crosses the defined
+ * threshold. The default value is meant to prevent the
+ * connection from being closed when the counter is about to
+ * reached its maximal value (it is not allowed to wrap).
+ *
+ * Lower values can be used to enforce policies such as "keys
+ * must be refreshed every N packets with cipher X".
+ *
+ * The renegotiation period can be disabled by setting
+ * conf->disable_renegotiation to
+ * MBEDTLS_SSL_RENEGOTIATION_DISABLED.
+ *
+ * \note When the configured transport is
+ * MBEDTLS_SSL_TRANSPORT_DATAGRAM the maximum renegotiation
+ * period is 2^48 - 1, and for MBEDTLS_SSL_TRANSPORT_STREAM,
+ * the maximum renegotiation period is 2^64 - 1.
+ *
+ * \param conf SSL configuration
+ * \param period The threshold value: a big-endian 64-bit number.
+ */
+void mbedtls_ssl_conf_renegotiation_period(mbedtls_ssl_config *conf,
+ const unsigned char period[8]);
+#endif /* MBEDTLS_SSL_RENEGOTIATION */
+
+/**
+ * \brief Check if there is data already read from the
+ * underlying transport but not yet processed.
+ *
+ * \param ssl SSL context
+ *
+ * \return 0 if nothing's pending, 1 otherwise.
+ *
+ * \note This is different in purpose and behaviour from
+ * \c mbedtls_ssl_get_bytes_avail in that it considers
+ * any kind of unprocessed data, not only unread
+ * application data. If \c mbedtls_ssl_get_bytes
+ * returns a non-zero value, this function will
+ * also signal pending data, but the converse does
+ * not hold. For example, in DTLS there might be
+ * further records waiting to be processed from
+ * the current underlying transport's datagram.
+ *
+ * \note If this function returns 1 (data pending), this
+ * does not imply that a subsequent call to
+ * \c mbedtls_ssl_read will provide any data;
+ * e.g., the unprocessed data might turn out
+ * to be an alert or a handshake message.
+ *
+ * \note This function is useful in the following situation:
+ * If the SSL/TLS module successfully returns from an
+ * operation - e.g. a handshake or an application record
+ * read - and you're awaiting incoming data next, you
+ * must not immediately idle on the underlying transport
+ * to have data ready, but you need to check the value
+ * of this function first. The reason is that the desired
+ * data might already be read but not yet processed.
+ * If, in contrast, a previous call to the SSL/TLS module
+ * returned MBEDTLS_ERR_SSL_WANT_READ, it is not necessary
+ * to call this function, as the latter error code entails
+ * that all internal data has been processed.
+ *
+ */
+int mbedtls_ssl_check_pending(const mbedtls_ssl_context *ssl);
+
+/**
+ * \brief Return the number of application data bytes
+ * remaining to be read from the current record.
+ *
+ * \param ssl SSL context
+ *
+ * \return How many bytes are available in the application
+ * data record read buffer.
+ *
+ * \note When working over a datagram transport, this is
+ * useful to detect the current datagram's boundary
+ * in case \c mbedtls_ssl_read has written the maximal
+ * amount of data fitting into the input buffer.
+ *
+ */
+size_t mbedtls_ssl_get_bytes_avail(const mbedtls_ssl_context *ssl);
+
+/**
+ * \brief Return the result of the certificate verification
+ *
+ * \param ssl The SSL context to use.
+ *
+ * \return \c 0 if the certificate verification was successful.
+ * \return \c -1u if the result is not available. This may happen
+ * e.g. if the handshake aborts early, or a verification
+ * callback returned a fatal error.
+ * \return A bitwise combination of \c MBEDTLS_X509_BADCERT_XXX
+ * and \c MBEDTLS_X509_BADCRL_XXX failure flags; see x509.h.
+ */
+uint32_t mbedtls_ssl_get_verify_result(const mbedtls_ssl_context *ssl);
+
+/**
+ * \brief Return the id of the current ciphersuite
+ *
+ * \param ssl SSL context
+ *
+ * \return a ciphersuite id
+ */
+int mbedtls_ssl_get_ciphersuite_id_from_ssl(const mbedtls_ssl_context *ssl);
+
+/**
+ * \brief Return the name of the current ciphersuite
+ *
+ * \param ssl SSL context
+ *
+ * \return a string containing the ciphersuite name
+ */
+const char *mbedtls_ssl_get_ciphersuite(const mbedtls_ssl_context *ssl);
+
+
+/**
+ * \brief Return the (D)TLS protocol version negotiated in the
+ * given connection.
+ *
+ * \note If you call this function too early during the initial
+ * handshake, before the two sides have agreed on a version,
+ * this function returns #MBEDTLS_SSL_VERSION_UNKNOWN.
+ *
+ * \param ssl The SSL context to query.
+ * \return The negotiated protocol version.
+ */
+static inline mbedtls_ssl_protocol_version mbedtls_ssl_get_version_number(
+ const mbedtls_ssl_context *ssl)
+{
+ return ssl->MBEDTLS_PRIVATE(tls_version);
+}
+
+/**
+ * \brief Return the current TLS version
+ *
+ * \param ssl SSL context
+ *
+ * \return a string containing the TLS version
+ */
+const char *mbedtls_ssl_get_version(const mbedtls_ssl_context *ssl);
+
+/**
+ * \brief Return the (maximum) number of bytes added by the record
+ * layer: header + encryption/MAC overhead (inc. padding)
+ *
+ * \param ssl SSL context
+ *
+ * \return Current maximum record expansion in bytes
+ */
+int mbedtls_ssl_get_record_expansion(const mbedtls_ssl_context *ssl);
+
+/**
+ * \brief Return the current maximum outgoing record payload in bytes.
+ *
+ * \note The logic to determine the maximum outgoing record payload is
+ * version-specific. It takes into account various factors, such as
+ * the mbedtls_config.h setting \c MBEDTLS_SSL_OUT_CONTENT_LEN, extensions
+ * such as the max fragment length or record size limit extension if
+ * used, and for DTLS the path MTU as configured and current
+ * record expansion.
+ *
+ * \note With DTLS, \c mbedtls_ssl_write() will return an error if
+ * called with a larger length value.
+ * With TLS, \c mbedtls_ssl_write() will fragment the input if
+ * necessary and return the number of bytes written; it is up
+ * to the caller to call \c mbedtls_ssl_write() again in
+ * order to send the remaining bytes if any.
+ *
+ * \sa mbedtls_ssl_get_max_out_record_payload()
+ * \sa mbedtls_ssl_get_record_expansion()
+ *
+ * \param ssl SSL context
+ *
+ * \return Current maximum payload for an outgoing record,
+ * or a negative error code.
+ */
+int mbedtls_ssl_get_max_out_record_payload(const mbedtls_ssl_context *ssl);
+
+/**
+ * \brief Return the current maximum incoming record payload in bytes.
+ *
+ * \note The logic to determine the maximum incoming record payload is
+ * version-specific. It takes into account various factors, such as
+ * the mbedtls_config.h setting \c MBEDTLS_SSL_IN_CONTENT_LEN, extensions
+ * such as the max fragment length extension or record size limit
+ * extension if used, and the current record expansion.
+ *
+ * \sa mbedtls_ssl_set_mtu()
+ * \sa mbedtls_ssl_get_max_in_record_payload()
+ * \sa mbedtls_ssl_get_record_expansion()
+ *
+ * \param ssl SSL context
+ *
+ * \return Current maximum payload for an incoming record,
+ * or a negative error code.
+ */
+int mbedtls_ssl_get_max_in_record_payload(const mbedtls_ssl_context *ssl);
+
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+/**
+ * \brief Return the peer certificate from the current connection.
+ *
+ * \param ssl The SSL context to use. This must be initialized and setup.
+ *
+ * \return The current peer certificate, if available.
+ * The returned certificate is owned by the SSL context and
+ * is valid only until the next call to the SSL API.
+ * \return \c NULL if no peer certificate is available. This might
+ * be because the chosen ciphersuite doesn't use CRTs
+ * (PSK-based ciphersuites, for example), or because
+ * #MBEDTLS_SSL_KEEP_PEER_CERTIFICATE has been disabled,
+ * allowing the stack to free the peer's CRT to save memory.
+ *
+ * \note For one-time inspection of the peer's certificate during
+ * the handshake, consider registering an X.509 CRT verification
+ * callback through mbedtls_ssl_conf_verify() instead of calling
+ * this function. Using mbedtls_ssl_conf_verify() also comes at
+ * the benefit of allowing you to influence the verification
+ * process, for example by masking expected and tolerated
+ * verification failures.
+ *
+ * \warning You must not use the pointer returned by this function
+ * after any further call to the SSL API, including
+ * mbedtls_ssl_read() and mbedtls_ssl_write(); this is
+ * because the pointer might change during renegotiation,
+ * which happens transparently to the user.
+ * If you want to use the certificate across API calls,
+ * you must make a copy.
+ */
+const mbedtls_x509_crt *mbedtls_ssl_get_peer_cert(const mbedtls_ssl_context *ssl);
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
+
+#if defined(MBEDTLS_SSL_CLI_C)
+/**
+ * \brief Export a session in order to resume it later.
+ *
+ * \param ssl The SSL context representing the connection for which to
+ * to export a session structure for later resumption.
+ * \param session The target structure in which to store the exported session.
+ * This must have been initialized with mbedtls_ssl_init_session()
+ * but otherwise be unused.
+ *
+ * \note This function can handle a variety of mechanisms for session
+ * resumption: For TLS 1.2, both session ID-based resumption and
+ * ticket-based resumption will be considered. For TLS 1.3,
+ * once implemented, sessions equate to tickets, and calling
+ * this function multiple times will export the available
+ * tickets one a time until no further tickets are available,
+ * in which case MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE will
+ * be returned.
+ *
+ * \note Calling this function multiple times will only be useful
+ * once TLS 1.3 is supported. For TLS 1.2 connections, this
+ * function should be called at most once.
+ *
+ * \return \c 0 if successful. In this case, \p session can be used for
+ * session resumption by passing it to mbedtls_ssl_set_session(),
+ * and serialized for storage via mbedtls_ssl_session_save().
+ * \return #MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE if no further session
+ * is available for export.
+ * This error is a non-fatal, and has no observable effect on
+ * the SSL context or the destination session.
+ * \return Another negative error code on other kinds of failure.
+ *
+ * \sa mbedtls_ssl_set_session()
+ * \sa mbedtls_ssl_session_save()
+ */
+int mbedtls_ssl_get_session(const mbedtls_ssl_context *ssl,
+ mbedtls_ssl_session *session);
+#endif /* MBEDTLS_SSL_CLI_C */
+
+/**
+ * \brief Perform the SSL handshake
+ *
+ * \param ssl SSL context
+ *
+ * \return \c 0 if successful.
+ * \return #MBEDTLS_ERR_SSL_WANT_READ or #MBEDTLS_ERR_SSL_WANT_WRITE
+ * if the handshake is incomplete and waiting for data to
+ * be available for reading from or writing to the underlying
+ * transport - in this case you must call this function again
+ * when the underlying transport is ready for the operation.
+ * \return #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if an asynchronous
+ * operation is in progress (see
+ * mbedtls_ssl_conf_async_private_cb()) - in this case you
+ * must call this function again when the operation is ready.
+ * \return #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS if a cryptographic
+ * operation is in progress (see mbedtls_ecp_set_max_ops()) -
+ * in this case you must call this function again to complete
+ * the handshake when you're done attending other tasks.
+ * \return #MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED if DTLS is in use
+ * and the client did not demonstrate reachability yet - in
+ * this case you must stop using the context (see below).
+ * \return Another SSL error code - in this case you must stop using
+ * the context (see below).
+ *
+ * \warning If this function returns something other than
+ * \c 0,
+ * #MBEDTLS_ERR_SSL_WANT_READ,
+ * #MBEDTLS_ERR_SSL_WANT_WRITE,
+ * #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS or
+ * #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS,
+ * you must stop using the SSL context for reading or writing,
+ * and either free it or call \c mbedtls_ssl_session_reset()
+ * on it before re-using it for a new connection; the current
+ * connection must be closed.
+ *
+ * \note If DTLS is in use, then you may choose to handle
+ * #MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED specially for logging
+ * purposes, as it is an expected return value rather than an
+ * actual error, but you still need to reset/free the context.
+ *
+ * \note Remarks regarding event-driven DTLS:
+ * If the function returns #MBEDTLS_ERR_SSL_WANT_READ, no datagram
+ * from the underlying transport layer is currently being processed,
+ * and it is safe to idle until the timer or the underlying transport
+ * signal a new event. This is not true for a successful handshake,
+ * in which case the datagram of the underlying transport that is
+ * currently being processed might or might not contain further
+ * DTLS records.
+ *
+ * \note If the context is configured to allow TLS 1.3, or if
+ * #MBEDTLS_USE_PSA_CRYPTO is enabled, the PSA crypto
+ * subsystem must have been initialized by calling
+ * psa_crypto_init() before calling this function.
+ */
+int mbedtls_ssl_handshake(mbedtls_ssl_context *ssl);
+
+/**
+ * \brief After calling mbedtls_ssl_handshake() to start the SSL
+ * handshake you can call this function to check whether the
+ * handshake is over for a given SSL context. This function
+ * should be also used to determine when to stop calling
+ * mbedtls_handshake_step() for that context.
+ *
+ * \param ssl SSL context
+ *
+ * \return \c 1 if handshake is over, \c 0 if it is still ongoing.
+ */
+static inline int mbedtls_ssl_is_handshake_over(mbedtls_ssl_context *ssl)
+{
+ return ssl->MBEDTLS_PRIVATE(state) >= MBEDTLS_SSL_HANDSHAKE_OVER;
+}
+
+/**
+ * \brief Perform a single step of the SSL handshake
+ *
+ * \note The state of the context (ssl->state) will be at
+ * the next state after this function returns \c 0. Do not
+ * call this function if mbedtls_ssl_is_handshake_over()
+ * returns \c 1.
+ *
+ * \warning Whilst in the past you may have used direct access to the
+ * context state (ssl->state) in order to ascertain when to
+ * stop calling this function and although you can still do
+ * so with something like ssl->MBEDTLS_PRIVATE(state) or by
+ * defining MBEDTLS_ALLOW_PRIVATE_ACCESS, this is now
+ * considered deprecated and could be broken in any future
+ * release. If you still find you have good reason for such
+ * direct access, then please do contact the team to explain
+ * this (raise an issue or post to the mailing list), so that
+ * we can add a solution to your problem that will be
+ * guaranteed to work in the future.
+ *
+ * \param ssl SSL context
+ *
+ * \return See mbedtls_ssl_handshake().
+ *
+ * \warning If this function returns something other than \c 0,
+ * #MBEDTLS_ERR_SSL_WANT_READ, #MBEDTLS_ERR_SSL_WANT_WRITE,
+ * #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS or
+ * #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS, you must stop using
+ * the SSL context for reading or writing, and either free it
+ * or call \c mbedtls_ssl_session_reset() on it before
+ * re-using it for a new connection; the current connection
+ * must be closed.
+ */
+int mbedtls_ssl_handshake_step(mbedtls_ssl_context *ssl);
+
+#if defined(MBEDTLS_SSL_RENEGOTIATION)
+/**
+ * \brief Initiate an SSL renegotiation on the running connection.
+ * Client: perform the renegotiation right now.
+ * Server: request renegotiation, which will be performed
+ * during the next call to mbedtls_ssl_read() if honored by
+ * client.
+ *
+ * \param ssl SSL context
+ *
+ * \return 0 if successful, or any mbedtls_ssl_handshake() return
+ * value except #MBEDTLS_ERR_SSL_CLIENT_RECONNECT that can't
+ * happen during a renegotiation.
+ *
+ * \warning If this function returns something other than \c 0,
+ * #MBEDTLS_ERR_SSL_WANT_READ, #MBEDTLS_ERR_SSL_WANT_WRITE,
+ * #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS or
+ * #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS, you must stop using
+ * the SSL context for reading or writing, and either free it
+ * or call \c mbedtls_ssl_session_reset() on it before
+ * re-using it for a new connection; the current connection
+ * must be closed.
+ *
+ */
+int mbedtls_ssl_renegotiate(mbedtls_ssl_context *ssl);
+#endif /* MBEDTLS_SSL_RENEGOTIATION */
+
+/**
+ * \brief Read at most 'len' application data bytes
+ *
+ * \param ssl SSL context
+ * \param buf buffer that will hold the data
+ * \param len maximum number of bytes to read
+ *
+ * \return The (positive) number of bytes read if successful.
+ * \return \c 0 if the read end of the underlying transport was closed
+ * without sending a CloseNotify beforehand, which might happen
+ * because of various reasons (internal error of an underlying
+ * stack, non-conformant peer not sending a CloseNotify and
+ * such) - in this case you must stop using the context
+ * (see below).
+ * \return #MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY if the underlying
+ * transport is still functional, but the peer has
+ * acknowledged to not send anything anymore.
+ * \return #MBEDTLS_ERR_SSL_WANT_READ or #MBEDTLS_ERR_SSL_WANT_WRITE
+ * if the handshake is incomplete and waiting for data to
+ * be available for reading from or writing to the underlying
+ * transport - in this case you must call this function again
+ * when the underlying transport is ready for the operation.
+ * \return #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if an asynchronous
+ * operation is in progress (see
+ * mbedtls_ssl_conf_async_private_cb()) - in this case you
+ * must call this function again when the operation is ready.
+ * \return #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS if a cryptographic
+ * operation is in progress (see mbedtls_ecp_set_max_ops()) -
+ * in this case you must call this function again to complete
+ * the handshake when you're done attending other tasks.
+ * \return #MBEDTLS_ERR_SSL_CLIENT_RECONNECT if we're at the server
+ * side of a DTLS connection and the client is initiating a
+ * new connection using the same source port. See below.
+ * \return Another SSL error code - in this case you must stop using
+ * the context (see below).
+ *
+ * \warning If this function returns something other than
+ * a positive value,
+ * #MBEDTLS_ERR_SSL_WANT_READ,
+ * #MBEDTLS_ERR_SSL_WANT_WRITE,
+ * #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS,
+ * #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS or
+ * #MBEDTLS_ERR_SSL_CLIENT_RECONNECT,
+ * you must stop using the SSL context for reading or writing,
+ * and either free it or call \c mbedtls_ssl_session_reset()
+ * on it before re-using it for a new connection; the current
+ * connection must be closed.
+ *
+ * \note When this function returns #MBEDTLS_ERR_SSL_CLIENT_RECONNECT
+ * (which can only happen server-side), it means that a client
+ * is initiating a new connection using the same source port.
+ * You can either treat that as a connection close and wait
+ * for the client to resend a ClientHello, or directly
+ * continue with \c mbedtls_ssl_handshake() with the same
+ * context (as it has been reset internally). Either way, you
+ * must make sure this is seen by the application as a new
+ * connection: application state, if any, should be reset, and
+ * most importantly the identity of the client must be checked
+ * again. WARNING: not validating the identity of the client
+ * again, or not transmitting the new identity to the
+ * application layer, would allow authentication bypass!
+ *
+ * \note Remarks regarding event-driven DTLS:
+ * - If the function returns #MBEDTLS_ERR_SSL_WANT_READ, no datagram
+ * from the underlying transport layer is currently being processed,
+ * and it is safe to idle until the timer or the underlying transport
+ * signal a new event.
+ * - This function may return MBEDTLS_ERR_SSL_WANT_READ even if data was
+ * initially available on the underlying transport, as this data may have
+ * been only e.g. duplicated messages or a renegotiation request.
+ * Therefore, you must be prepared to receive MBEDTLS_ERR_SSL_WANT_READ even
+ * when reacting to an incoming-data event from the underlying transport.
+ * - On success, the datagram of the underlying transport that is currently
+ * being processed may contain further DTLS records. You should call
+ * \c mbedtls_ssl_check_pending to check for remaining records.
+ *
+ */
+int mbedtls_ssl_read(mbedtls_ssl_context *ssl, unsigned char *buf, size_t len);
+
+/**
+ * \brief Try to write exactly 'len' application data bytes
+ *
+ * \warning This function will do partial writes in some cases. If the
+ * return value is non-negative but less than length, the
+ * function must be called again with updated arguments:
+ * buf + ret, len - ret (if ret is the return value) until
+ * it returns a value equal to the last 'len' argument.
+ *
+ * \param ssl SSL context
+ * \param buf buffer holding the data
+ * \param len how many bytes must be written
+ *
+ * \return The (non-negative) number of bytes actually written if
+ * successful (may be less than \p len).
+ * \return #MBEDTLS_ERR_SSL_WANT_READ or #MBEDTLS_ERR_SSL_WANT_WRITE
+ * if the handshake is incomplete and waiting for data to
+ * be available for reading from or writing to the underlying
+ * transport - in this case you must call this function again
+ * when the underlying transport is ready for the operation.
+ * \return #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS if an asynchronous
+ * operation is in progress (see
+ * mbedtls_ssl_conf_async_private_cb()) - in this case you
+ * must call this function again when the operation is ready.
+ * \return #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS if a cryptographic
+ * operation is in progress (see mbedtls_ecp_set_max_ops()) -
+ * in this case you must call this function again to complete
+ * the handshake when you're done attending other tasks.
+ * \return Another SSL error code - in this case you must stop using
+ * the context (see below).
+ *
+ * \warning If this function returns something other than
+ * a non-negative value,
+ * #MBEDTLS_ERR_SSL_WANT_READ,
+ * #MBEDTLS_ERR_SSL_WANT_WRITE,
+ * #MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS or
+ * #MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS,
+ * you must stop using the SSL context for reading or writing,
+ * and either free it or call \c mbedtls_ssl_session_reset()
+ * on it before re-using it for a new connection; the current
+ * connection must be closed.
+ *
+ * \note When this function returns #MBEDTLS_ERR_SSL_WANT_WRITE/READ,
+ * it must be called later with the *same* arguments,
+ * until it returns a value greater than or equal to 0. When
+ * the function returns #MBEDTLS_ERR_SSL_WANT_WRITE there may be
+ * some partial data in the output buffer, however this is not
+ * yet sent.
+ *
+ * \note If the requested length is greater than the maximum
+ * fragment length (either the built-in limit or the one set
+ * or negotiated with the peer), then:
+ * - with TLS, less bytes than requested are written.
+ * - with DTLS, MBEDTLS_ERR_SSL_BAD_INPUT_DATA is returned.
+ * \c mbedtls_ssl_get_max_out_record_payload() may be used to
+ * query the active maximum fragment length.
+ *
+ * \note Attempting to write 0 bytes will result in an empty TLS
+ * application record being sent.
+ */
+int mbedtls_ssl_write(mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len);
+
+/**
+ * \brief Send an alert message
+ *
+ * \param ssl SSL context
+ * \param level The alert level of the message
+ * (MBEDTLS_SSL_ALERT_LEVEL_WARNING or MBEDTLS_SSL_ALERT_LEVEL_FATAL)
+ * \param message The alert message (SSL_ALERT_MSG_*)
+ *
+ * \return 0 if successful, or a specific SSL error code.
+ *
+ * \note If this function returns something other than 0 or
+ * MBEDTLS_ERR_SSL_WANT_READ/WRITE, you must stop using
+ * the SSL context for reading or writing, and either free it or
+ * call \c mbedtls_ssl_session_reset() on it before re-using it
+ * for a new connection; the current connection must be closed.
+ */
+int mbedtls_ssl_send_alert_message(mbedtls_ssl_context *ssl,
+ unsigned char level,
+ unsigned char message);
+/**
+ * \brief Notify the peer that the connection is being closed
+ *
+ * \param ssl SSL context
+ *
+ * \return 0 if successful, or a specific SSL error code.
+ *
+ * \note If this function returns something other than 0 or
+ * MBEDTLS_ERR_SSL_WANT_READ/WRITE, you must stop using
+ * the SSL context for reading or writing, and either free it or
+ * call \c mbedtls_ssl_session_reset() on it before re-using it
+ * for a new connection; the current connection must be closed.
+ */
+int mbedtls_ssl_close_notify(mbedtls_ssl_context *ssl);
+
+#if defined(MBEDTLS_SSL_EARLY_DATA)
+
+#if defined(MBEDTLS_SSL_SRV_C)
+/**
+ * \brief Read at most 'len' application data bytes while performing
+ * the handshake (early data).
+ *
+ * \note This function behaves mainly as mbedtls_ssl_read(). The
+ * specification of mbedtls_ssl_read() relevant to TLS 1.3
+ * (thus not the parts specific to (D)TLS 1.2) applies to this
+ * function and the present documentation is restricted to the
+ * differences with mbedtls_ssl_read().
+ *
+ * \param ssl SSL context
+ * \param buf buffer that will hold the data
+ * \param len maximum number of bytes to read
+ *
+ * \return One additional specific return value:
+ * #MBEDTLS_ERR_SSL_CANNOT_READ_EARLY_DATA.
+ *
+ * #MBEDTLS_ERR_SSL_CANNOT_READ_EARLY_DATA is returned when it
+ * is not possible to read early data for the SSL context
+ * \p ssl.
+ *
+ * It may have been possible and it is not possible
+ * anymore because the server received the End of Early Data
+ * message or the maximum number of allowed early data for the
+ * PSK in use has been reached.
+ *
+ * It may never have been possible and will never be possible
+ * for the SSL context \p ssl because the use of early data
+ * is disabled for that context or more generally the context
+ * is not suitably configured to enable early data or the
+ * client does not use early data or the first call to the
+ * function was done while the handshake was already too
+ * advanced to gather and accept early data.
+ *
+ * It is not possible to read early data for the SSL context
+ * \p ssl but this does not preclude for using it with
+ * mbedtls_ssl_write(), mbedtls_ssl_read() or
+ * mbedtls_ssl_handshake().
+ *
+ * \note When a server wants to retrieve early data, it is expected
+ * that this function starts the handshake for the SSL context
+ * \p ssl. But this is not mandatory.
+ *
+ */
+int mbedtls_ssl_read_early_data(mbedtls_ssl_context *ssl,
+ unsigned char *buf, size_t len);
+#endif /* MBEDTLS_SSL_SRV_C */
+
+#if defined(MBEDTLS_SSL_CLI_C)
+/**
+ * \brief Try to write exactly 'len' application data bytes while
+ * performing the handshake (early data).
+ *
+ * \note This function behaves mainly as mbedtls_ssl_write(). The
+ * specification of mbedtls_ssl_write() relevant to TLS 1.3
+ * (thus not the parts specific to (D)TLS1.2) applies to this
+ * function and the present documentation is restricted to the
+ * differences with mbedtls_ssl_write().
+ *
+ * \param ssl SSL context
+ * \param buf buffer holding the data
+ * \param len how many bytes must be written
+ *
+ * \return One additional specific return value:
+ * #MBEDTLS_ERR_SSL_CANNOT_WRITE_EARLY_DATA.
+ *
+ * #MBEDTLS_ERR_SSL_CANNOT_WRITE_EARLY_DATA is returned when it
+ * is not possible to write early data for the SSL context
+ * \p ssl.
+ *
+ * It may have been possible and it is not possible
+ * anymore because the client received the server Finished
+ * message, the server rejected early data or the maximum
+ * number of allowed early data for the PSK in use has been
+ * reached.
+ *
+ * It may never have been possible and will never be possible
+ * for the SSL context \p ssl because the use of early data
+ * is disabled for that context or more generally the context
+ * is not suitably configured to enable early data or the first
+ * call to the function was done while the handshake was
+ * already completed.
+ *
+ * It is not possible to write early data for the SSL context
+ * \p ssl but this does not preclude for using it with
+ * mbedtls_ssl_write(), mbedtls_ssl_read() or
+ * mbedtls_ssl_handshake().
+ *
+ * \note This function may write early data only if the SSL context
+ * has been configured for the handshake with a PSK for which
+ * early data is allowed.
+ *
+ * \note To maximize the number of early data that can be written in
+ * the course of the handshake, it is expected that this
+ * function starts the handshake for the SSL context \p ssl.
+ * But this is not mandatory.
+ *
+ * \note This function does not provide any information on whether
+ * the server has accepted or will accept early data or not.
+ * When it returns a positive value, it just means that it
+ * has written early data to the server. To know whether the
+ * server has accepted early data or not, you should call
+ * mbedtls_ssl_get_early_data_status() with the handshake
+ * completed.
+ */
+int mbedtls_ssl_write_early_data(mbedtls_ssl_context *ssl,
+ const unsigned char *buf, size_t len);
+
+#define MBEDTLS_SSL_EARLY_DATA_STATUS_NOT_SENT 0
+#define MBEDTLS_SSL_EARLY_DATA_STATUS_ACCEPTED 1
+#define MBEDTLS_SSL_EARLY_DATA_STATUS_REJECTED 2
+/**
+ * \brief Get the status of the negotiation of the use of early data.
+ *
+ * \param ssl The SSL context to query
+ *
+ * \return #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if this function is called
+ * from the server-side.
+ *
+ * \return #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if this function is called
+ * prior to completion of the handshake.
+ *
+ * \return #MBEDTLS_SSL_EARLY_DATA_STATUS_NOT_SENT if the client has
+ * not indicated the use of early data to the server.
+ *
+ * \return #MBEDTLS_SSL_EARLY_DATA_STATUS_ACCEPTED if the client has
+ * indicated the use of early data and the server has accepted
+ * it.
+ *
+ * \return #MBEDTLS_SSL_EARLY_DATA_STATUS_REJECTED if the client has
+ * indicated the use of early data but the server has rejected
+ * it. In this situation, the client may want to re-send the
+ * early data it may have tried to send by calling
+ * mbedtls_ssl_write_early_data() as ordinary post-handshake
+ * application data by calling mbedtls_ssl_write().
+ *
+ */
+int mbedtls_ssl_get_early_data_status(mbedtls_ssl_context *ssl);
+#endif /* MBEDTLS_SSL_CLI_C */
+
+#endif /* MBEDTLS_SSL_EARLY_DATA */
+
+/**
+ * \brief Free referenced items in an SSL context and clear memory
+ *
+ * \param ssl SSL context
+ */
+void mbedtls_ssl_free(mbedtls_ssl_context *ssl);
+
+#if defined(MBEDTLS_SSL_CONTEXT_SERIALIZATION)
+/**
+ * \brief Save an active connection as serialized data in a buffer.
+ * This allows the freeing or re-using of the SSL context
+ * while still picking up the connection later in a way that
+ * it entirely transparent to the peer.
+ *
+ * \see mbedtls_ssl_context_load()
+ *
+ * \note The serialized data only contains the data that is
+ * necessary to resume the connection: negotiated protocol
+ * options, session identifier, keys, etc.
+ * Loading a saved SSL context does not restore settings and
+ * state related to how the application accesses the context,
+ * such as configured callback functions, user data, pending
+ * incoming or outgoing data, etc.
+ *
+ * \note This feature is currently only available under certain
+ * conditions, see the documentation of the return value
+ * #MBEDTLS_ERR_SSL_BAD_INPUT_DATA for details.
+ *
+ * \note When this function succeeds, it calls
+ * mbedtls_ssl_session_reset() on \p ssl which as a result is
+ * no longer associated with the connection that has been
+ * serialized. This avoids creating copies of the connection
+ * state. You're then free to either re-use the context
+ * structure for a different connection, or call
+ * mbedtls_ssl_free() on it. See the documentation of
+ * mbedtls_ssl_session_reset() for more details.
+ *
+ * \param ssl The SSL context to save. On success, it is no longer
+ * associated with the connection that has been serialized.
+ * \param buf The buffer to write the serialized data to. It must be a
+ * writeable buffer of at least \p buf_len bytes, or may be \c
+ * NULL if \p buf_len is \c 0.
+ * \param buf_len The number of bytes available for writing in \p buf.
+ * \param olen The size in bytes of the data that has been or would have
+ * been written. It must point to a valid \c size_t.
+ *
+ * \note \p olen is updated to the correct value regardless of
+ * whether \p buf_len was large enough. This makes it possible
+ * to determine the necessary size by calling this function
+ * with \p buf set to \c NULL and \p buf_len to \c 0. However,
+ * the value of \p olen is only guaranteed to be correct when
+ * the function returns #MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL or
+ * \c 0. If the return value is different, then the value of
+ * \p olen is undefined.
+ *
+ * \return \c 0 if successful.
+ * \return #MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL if \p buf is too small.
+ * \return #MBEDTLS_ERR_SSL_ALLOC_FAILED if memory allocation failed
+ * while resetting the context.
+ * \return #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if a handshake is in
+ * progress, or there is pending data for reading or sending,
+ * or the connection does not use DTLS 1.2 with an AEAD
+ * ciphersuite, or renegotiation is enabled.
+ */
+int mbedtls_ssl_context_save(mbedtls_ssl_context *ssl,
+ unsigned char *buf,
+ size_t buf_len,
+ size_t *olen);
+
+/**
+ * \brief Load serialized connection data to an SSL context.
+ *
+ * \see mbedtls_ssl_context_save()
+ *
+ * \warning The same serialized data must never be loaded into more
+ * that one context. In order to ensure that, after
+ * successfully loading serialized data to an SSL context, you
+ * should immediately destroy or invalidate all copies of the
+ * serialized data that was loaded. Loading the same data in
+ * more than one context would cause severe security failures
+ * including but not limited to loss of confidentiality.
+ *
+ * \note Before calling this function, the SSL context must be
+ * prepared in one of the two following ways. The first way is
+ * to take a context freshly initialised with
+ * mbedtls_ssl_init() and call mbedtls_ssl_setup() on it with
+ * the same ::mbedtls_ssl_config structure that was used in
+ * the original connection. The second way is to
+ * call mbedtls_ssl_session_reset() on a context that was
+ * previously prepared as above but used in the meantime.
+ * Either way, you must not use the context to perform a
+ * handshake between calling mbedtls_ssl_setup() or
+ * mbedtls_ssl_session_reset() and calling this function. You
+ * may however call other setter functions in that time frame
+ * as indicated in the note below.
+ *
+ * \note Before or after calling this function successfully, you
+ * also need to configure some connection-specific callbacks
+ * and settings before you can use the connection again
+ * (unless they were already set before calling
+ * mbedtls_ssl_session_reset() and the values are suitable for
+ * the present connection). Specifically, you want to call
+ * at least mbedtls_ssl_set_bio(),
+ * mbedtls_ssl_set_timer_cb(), and
+ * mbedtls_ssl_set_user_data_n() or
+ * mbedtls_ssl_set_user_data_p() if they were set originally.
+ * All other SSL setter functions
+ * are not necessary to call, either because they're only used
+ * in handshakes, or because the setting is already saved. You
+ * might choose to call them anyway, for example in order to
+ * share code between the cases of establishing a new
+ * connection and the case of loading an already-established
+ * connection.
+ *
+ * \note If you have new information about the path MTU, you want to
+ * call mbedtls_ssl_set_mtu() after calling this function, as
+ * otherwise this function would overwrite your
+ * newly-configured value with the value that was active when
+ * the context was saved.
+ *
+ * \note When this function returns an error code, it calls
+ * mbedtls_ssl_free() on \p ssl. In this case, you need to
+ * prepare the context with the usual sequence starting with a
+ * call to mbedtls_ssl_init() if you want to use it again.
+ *
+ * \param ssl The SSL context structure to be populated. It must have
+ * been prepared as described in the note above.
+ * \param buf The buffer holding the serialized connection data. It must
+ * be a readable buffer of at least \p len bytes.
+ * \param len The size of the serialized data in bytes.
+ *
+ * \return \c 0 if successful.
+ * \return #MBEDTLS_ERR_SSL_ALLOC_FAILED if memory allocation failed.
+ * \return #MBEDTLS_ERR_SSL_VERSION_MISMATCH if the serialized data
+ * comes from a different Mbed TLS version or build.
+ * \return #MBEDTLS_ERR_SSL_BAD_INPUT_DATA if input data is invalid.
+ */
+int mbedtls_ssl_context_load(mbedtls_ssl_context *ssl,
+ const unsigned char *buf,
+ size_t len);
+#endif /* MBEDTLS_SSL_CONTEXT_SERIALIZATION */
+
+/**
+ * \brief Initialize an SSL configuration context
+ * Just makes the context ready for
+ * mbedtls_ssl_config_defaults() or mbedtls_ssl_config_free().
+ *
+ * \note You need to call mbedtls_ssl_config_defaults() unless you
+ * manually set all of the relevant fields yourself.
+ *
+ * \param conf SSL configuration context
+ */
+void mbedtls_ssl_config_init(mbedtls_ssl_config *conf);
+
+/**
+ * \brief Load reasonable default SSL configuration values.
+ * (You need to call mbedtls_ssl_config_init() first.)
+ *
+ * \param conf SSL configuration context
+ * \param endpoint MBEDTLS_SSL_IS_CLIENT or MBEDTLS_SSL_IS_SERVER
+ * \param transport MBEDTLS_SSL_TRANSPORT_STREAM for TLS, or
+ * MBEDTLS_SSL_TRANSPORT_DATAGRAM for DTLS
+ * \param preset a MBEDTLS_SSL_PRESET_XXX value
+ *
+ * \note See \c mbedtls_ssl_conf_transport() for notes on DTLS.
+ *
+ * \return 0 if successful, or
+ * MBEDTLS_ERR_XXX_ALLOC_FAILED on memory allocation error.
+ */
+int mbedtls_ssl_config_defaults(mbedtls_ssl_config *conf,
+ int endpoint, int transport, int preset);
+
+/**
+ * \brief Free an SSL configuration context
+ *
+ * \param conf SSL configuration context
+ */
+void mbedtls_ssl_config_free(mbedtls_ssl_config *conf);
+
+/**
+ * \brief Initialize SSL session structure
+ *
+ * \param session SSL session
+ */
+void mbedtls_ssl_session_init(mbedtls_ssl_session *session);
+
+/**
+ * \brief Free referenced items in an SSL session including the
+ * peer certificate and clear memory
+ *
+ * \note A session object can be freed even if the SSL context
+ * that was used to retrieve the session is still in use.
+ *
+ * \param session SSL session
+ */
+void mbedtls_ssl_session_free(mbedtls_ssl_session *session);
+
+/**
+ * \brief TLS-PRF function for key derivation.
+ *
+ * \param prf The tls_prf type function type to be used.
+ * \param secret Secret for the key derivation function.
+ * \param slen Length of the secret.
+ * \param label String label for the key derivation function,
+ * terminated with null character.
+ * \param random Random bytes.
+ * \param rlen Length of the random bytes buffer.
+ * \param dstbuf The buffer holding the derived key.
+ * \param dlen Length of the output buffer.
+ *
+ * \return 0 on success. An SSL specific error on failure.
+ */
+int mbedtls_ssl_tls_prf(const mbedtls_tls_prf_types prf,
+ const unsigned char *secret, size_t slen,
+ const char *label,
+ const unsigned char *random, size_t rlen,
+ unsigned char *dstbuf, size_t dlen);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ssl.h */