programs/ssl/ssl_client2.c

/*
 *  SSL client with certificate authentication
 *
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

#define MBEDTLS_ALLOW_PRIVATE_ACCESS

#include "ssl_test_lib.h"

#if defined(MBEDTLS_USE_PSA_CRYPTO)
#include "test/psa_crypto_helpers.h"
#endif

#if defined(MBEDTLS_SSL_TEST_IMPOSSIBLE)
int main( void )
{
    mbedtls_printf( MBEDTLS_SSL_TEST_IMPOSSIBLE );
    mbedtls_exit( 0 );
}
#elif !defined(MBEDTLS_SSL_CLI_C)
int main( void )
{
    mbedtls_printf( "MBEDTLS_SSL_CLI_C not defined.\n" );
    mbedtls_exit( 0 );
}
#else /* !MBEDTLS_SSL_TEST_IMPOSSIBLE && MBEDTLS_SSL_CLI_C */

/* Size of memory to be allocated for the heap, when using the library's memory
 * management and MBEDTLS_MEMORY_BUFFER_ALLOC_C is enabled. */
#define MEMORY_HEAP_SIZE      120000

#define MAX_REQUEST_SIZE      20000
#define MAX_REQUEST_SIZE_STR "20000"

#define DFL_SERVER_NAME         "localhost"
#define DFL_SERVER_ADDR         NULL
#define DFL_SERVER_PORT         "4433"
#define DFL_REQUEST_PAGE        "/"
#define DFL_REQUEST_SIZE        -1
#define DFL_DEBUG_LEVEL         0
#define DFL_CONTEXT_CRT_CB      0
#define DFL_NBIO                0
#define DFL_EVENT               0
#define DFL_READ_TIMEOUT        0
#define DFL_MAX_RESEND          0
#define DFL_CA_FILE             ""
#define DFL_CA_PATH             ""
#define DFL_CRT_FILE            ""
#define DFL_KEY_FILE            ""
#define DFL_KEY_OPAQUE          0
#define DFL_KEY_PWD             ""
#define DFL_PSK                 ""
#define DFL_PSK_OPAQUE          0
#define DFL_PSK_IDENTITY        "Client_identity"
#define DFL_ECJPAKE_PW          NULL
#define DFL_EC_MAX_OPS          -1
#define DFL_FORCE_CIPHER        0
#define DFL_TLS13_KEX_MODES     MBEDTLS_SSL_TLS13_KEY_EXCHANGE_MODE_ALL
#define DFL_RENEGOTIATION       MBEDTLS_SSL_RENEGOTIATION_DISABLED
#define DFL_ALLOW_LEGACY        -2
#define DFL_RENEGOTIATE         0
#define DFL_EXCHANGES           1
#define DFL_MIN_VERSION         -1
#define DFL_MAX_VERSION         -1
#define DFL_SHA1                -1
#define DFL_AUTH_MODE           -1
#define DFL_MFL_CODE            MBEDTLS_SSL_MAX_FRAG_LEN_NONE
#define DFL_TRUNC_HMAC          -1
#define DFL_RECSPLIT            -1
#define DFL_DHMLEN              -1
#define DFL_RECONNECT           0
#define DFL_RECO_DELAY          0
#define DFL_RECO_MODE           1
#define DFL_CID_ENABLED         0
#define DFL_CID_VALUE           ""
#define DFL_CID_ENABLED_RENEGO  -1
#define DFL_CID_VALUE_RENEGO    NULL
#define DFL_RECONNECT_HARD      0
#define DFL_TICKETS             MBEDTLS_SSL_SESSION_TICKETS_ENABLED
#define DFL_ALPN_STRING         NULL
#define DFL_CURVES              NULL
#define DFL_SIG_ALGS            NULL
#define DFL_TRANSPORT           MBEDTLS_SSL_TRANSPORT_STREAM
#define DFL_HS_TO_MIN           0
#define DFL_HS_TO_MAX           0
#define DFL_DTLS_MTU            -1
#define DFL_DGRAM_PACKING        1
#define DFL_FALLBACK            -1
#define DFL_EXTENDED_MS         -1
#define DFL_ETM                 -1
#define DFL_SERIALIZE           0
#define DFL_CONTEXT_FILE        ""
#define DFL_EXTENDED_MS_ENFORCE -1
#define DFL_CA_CALLBACK         0
#define DFL_EAP_TLS             0
#define DFL_REPRODUCIBLE        0
#define DFL_NSS_KEYLOG          0
#define DFL_NSS_KEYLOG_FILE     NULL
#define DFL_SKIP_CLOSE_NOTIFY   0
#define DFL_QUERY_CONFIG_MODE   0
#define DFL_USE_SRTP            0
#define DFL_SRTP_FORCE_PROFILE  0
#define DFL_SRTP_MKI            ""

#define GET_REQUEST "GET %s HTTP/1.0\r\nExtra-header: "
#define GET_REQUEST_END "\r\n\r\n"

#if defined(MBEDTLS_X509_CRT_PARSE_C)
#define USAGE_CONTEXT_CRT_CB \
    "    context_crt_cb=%%d   This determines whether the CRT verification callback is bound\n" \
    "                        to the SSL configuration of the SSL context.\n" \
    "                        Possible values:\n"\
    "                        - 0 (default): Use CRT callback bound to configuration\n" \
    "                        - 1: Use CRT callback bound to SSL context\n"
#else
#define USAGE_CONTEXT_CRT_CB ""
#endif /* MBEDTLS_X509_CRT_PARSE_C */
#if defined(MBEDTLS_X509_CRT_PARSE_C)
#if defined(MBEDTLS_FS_IO)
#define USAGE_IO \
    "    ca_file=%%s          The single file containing the top-level CA(s) you fully trust\n" \
    "                        default: \"\" (pre-loaded)\n" \
    "                        use \"none\" to skip loading any top-level CAs.\n" \
    "    ca_path=%%s          The path containing the top-level CA(s) you fully trust\n" \
    "                        default: \"\" (pre-loaded) (overrides ca_file)\n" \
    "                        use \"none\" to skip loading any top-level CAs.\n" \
    "    crt_file=%%s         Your own cert and chain (in bottom to top order, top may be omitted)\n" \
    "                        default: \"\" (pre-loaded)\n" \
    "    key_file=%%s         default: \"\" (pre-loaded)\n"\
    "    key_pwd=%%s          Password for key specified by key_file argument\n"\
    "                        default: none\n"
#else
#define USAGE_IO \
    "    No file operations available (MBEDTLS_FS_IO not defined)\n"
#endif /* MBEDTLS_FS_IO */
#else /* MBEDTLS_X509_CRT_PARSE_C */
#define USAGE_IO ""
#endif /* MBEDTLS_X509_CRT_PARSE_C */
#if defined(MBEDTLS_USE_PSA_CRYPTO) && defined(MBEDTLS_X509_CRT_PARSE_C)
#define USAGE_KEY_OPAQUE \
    "    key_opaque=%%d       Handle your private key as if it were opaque\n" \
    "                        default: 0 (disabled)\n"
#else
#define USAGE_KEY_OPAQUE ""
#endif

#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
#define USAGE_CID \
    "    cid=%%d             Disable (0) or enable (1) the use of the DTLS Connection ID extension.\n" \
    "                       default: 0 (disabled)\n"     \
    "    cid_renego=%%d      Disable (0) or enable (1) the use of the DTLS Connection ID extension during renegotiation.\n" \
    "                       default: same as 'cid' parameter\n"     \
    "    cid_val=%%s          The CID to use for incoming messages (in hex, without 0x).\n"  \
    "                        default: \"\"\n" \
    "    cid_val_renego=%%s   The CID to use for incoming messages (in hex, without 0x) after renegotiation.\n"  \
    "                        default: same as 'cid_val' parameter\n"
#else /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
#define USAGE_CID ""
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */

#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
#define USAGE_PSK_RAW                                               \
    "    psk=%%s              default: \"\" (disabled)\n"     \
    "                          The PSK values are in hex, without 0x.\n" \
    "    psk_identity=%%s     default: \"Client_identity\"\n"
#if defined(MBEDTLS_USE_PSA_CRYPTO)
#define USAGE_PSK_SLOT                          \
    "    psk_opaque=%%d       default: 0 (don't use opaque static PSK)\n"     \
    "                          Enable this to store the PSK configured through command line\n" \
    "                          parameter `psk` in a PSA-based key slot.\n" \
    "                          Note: Currently only supported in conjunction with\n"                  \
    "                          the use of min_version to force TLS 1.2 and force_ciphersuite \n"      \
    "                          to force a particular PSK-only ciphersuite.\n"                         \
    "                          Note: This is to test integration of PSA-based opaque PSKs with\n"     \
    "                          Mbed TLS only. Production systems are likely to configure Mbed TLS\n"  \
    "                          with prepopulated key slots instead of importing raw key material.\n"
#else
#define USAGE_PSK_SLOT ""
#endif /* MBEDTLS_USE_PSA_CRYPTO */
#define USAGE_PSK USAGE_PSK_RAW USAGE_PSK_SLOT
#else
#define USAGE_PSK ""
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */

#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
#define USAGE_CA_CALLBACK                       \
    "   ca_callback=%%d       default: 0 (disabled)\n"      \
    "                         Enable this to use the trusted certificate callback function\n"
#else
#define USAGE_CA_CALLBACK ""
#endif /* MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK */

#if defined(MBEDTLS_SSL_SESSION_TICKETS)
#define USAGE_TICKETS                                       \
    "    tickets=%%d          default: 1 (enabled)\n"
#else
#define USAGE_TICKETS ""
#endif /* MBEDTLS_SSL_SESSION_TICKETS */

#define USAGE_EAP_TLS                                       \
    "    eap_tls=%%d          default: 0 (disabled)\n"
#define USAGE_NSS_KEYLOG                                    \
    "    nss_keylog=%%d          default: 0 (disabled)\n"               \
    "                             This cannot be used with eap_tls=1\n"
#define USAGE_NSS_KEYLOG_FILE                               \
    "    nss_keylog_file=%%s\n"
#if defined(MBEDTLS_SSL_DTLS_SRTP)
#define USAGE_SRTP \
    "    use_srtp=%%d         default: 0 (disabled)\n" \
    "                          This cannot be used with eap_tls=1 or "\
    "                          nss_keylog=1\n"             \
    "    srtp_force_profile=%%d  default: 0 (all enabled)\n"   \
    "                        available profiles:\n"       \
    "                        1 - SRTP_AES128_CM_HMAC_SHA1_80\n"  \
    "                        2 - SRTP_AES128_CM_HMAC_SHA1_32\n"  \
    "                        3 - SRTP_NULL_HMAC_SHA1_80\n"       \
    "                        4 - SRTP_NULL_HMAC_SHA1_32\n"       \
    "    mki=%%s              default: \"\" (in hex, without 0x)\n"
#else /* MBEDTLS_SSL_DTLS_SRTP */
#define USAGE_SRTP ""
#endif

#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
#define USAGE_MAX_FRAG_LEN                                      \
    "    max_frag_len=%%d     default: 16384 (tls default)\n"   \
    "                        options: 512, 1024, 2048, 4096\n"
#else
#define USAGE_MAX_FRAG_LEN ""
#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */

#if defined(MBEDTLS_DHM_C)
#define USAGE_DHMLEN \
    "    dhmlen=%%d           default: (library default: 1024 bits)\n"
#else
#define USAGE_DHMLEN
#endif

#if defined(MBEDTLS_SSL_ALPN)
#define USAGE_ALPN \
    "    alpn=%%s             default: \"\" (disabled)\n"   \
    "                        example: spdy/1,http/1.1\n"
#else
#define USAGE_ALPN ""
#endif /* MBEDTLS_SSL_ALPN */

#if defined(MBEDTLS_ECP_C)
#define USAGE_CURVES \
    "    curves=a,b,c,d      default: \"default\" (library default)\n"  \
    "                        example: \"secp521r1,brainpoolP512r1\"\n"  \
    "                        - use \"none\" for empty list\n"           \
    "                        - see mbedtls_ecp_curve_list()\n"          \
    "                          for acceptable curve names\n"
#else
#define USAGE_CURVES ""
#endif

#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) && \
    defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
#define USAGE_SIG_ALGS \
    "    sig_algs=a,b,c,d      default: \"default\" (library default)\n"  \
    "                          example: \"ecdsa_secp256r1_sha256,ecdsa_secp384r1_sha384\"\n"
#else
#define USAGE_SIG_ALGS ""
#endif

#if defined(MBEDTLS_SSL_PROTO_DTLS)
#define USAGE_DTLS \
    "    dtls=%%d             default: 0 (TLS)\n"                           \
    "    hs_timeout=%%d-%%d    default: (library default: 1000-60000)\n"    \
    "                        range of DTLS handshake timeouts in millisecs\n" \
    "    mtu=%%d              default: (library default: unlimited)\n"  \
    "    dgram_packing=%%d    default: 1 (allowed)\n"                   \
    "                        allow or forbid packing of multiple\n" \
    "                        records within a single datgram.\n"
#else
#define USAGE_DTLS ""
#endif

#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
#define USAGE_EMS \
    "    extended_ms=0/1     default: (library default: on)\n"
#else
#define USAGE_EMS ""
#endif

#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
#define USAGE_ETM \
    "    etm=0/1             default: (library default: on)\n"
#else
#define USAGE_ETM ""
#endif

#define USAGE_REPRODUCIBLE \
    "    reproducible=0/1     default: 0 (disabled)\n"

#if defined(MBEDTLS_SSL_RENEGOTIATION)
#define USAGE_RENEGO \
    "    renegotiation=%%d    default: 0 (disabled)\n"      \
    "    renegotiate=%%d      default: 0 (disabled)\n"
#else
#define USAGE_RENEGO ""
#endif

#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
#define USAGE_ECJPAKE \
    "    ecjpake_pw=%%s       default: none (disabled)\n"
#else
#define USAGE_ECJPAKE ""
#endif

#if defined(MBEDTLS_ECP_RESTARTABLE)
#define USAGE_ECRESTART \
    "    ec_max_ops=%%s       default: library default (restart disabled)\n"
#else
#define USAGE_ECRESTART ""
#endif

#if defined(MBEDTLS_SSL_CONTEXT_SERIALIZATION)
#define USAGE_SERIALIZATION \
    "    serialize=%%d        default: 0 (do not serialize/deserialize)\n"     \
    "                        options: 1 (serialize)\n"                         \
    "                                 2 (serialize with re-initialization)\n"  \
    "    context_file=%%s     The file path to write a serialized connection\n"\
    "                        in the form of base64 code (serialize option\n"   \
    "                        must be set)\n"                                   \
    "                         default: \"\" (do nothing)\n"                    \
    "                         option: a file path\n"
#else
#define USAGE_SERIALIZATION ""
#endif

#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
#define USAGE_TLS13_KEY_EXCHANGE_MODES \
    "    tls13_kex_modes=%%s   default: all\n"     \
    "                          options: psk, psk_ephemeral, ephemeral, ephemeral_all, psk_all, all\n"
#else
#define USAGE_TLS13_KEY_EXCHANGE_MODES ""
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */

/* USAGE is arbitrarily split to stay under the portable string literal
 * length limit: 4095 bytes in C99. */
#define USAGE1 \
    "\n usage: ssl_client2 param=<>...\n"                   \
    "\n acceptable parameters:\n"                           \
    "    server_name=%%s      default: localhost\n"         \
    "    server_addr=%%s      default: given by name\n"     \
    "    server_port=%%d      default: 4433\n"              \
    "    request_page=%%s     default: \".\"\n"             \
    "    request_size=%%d     default: about 34 (basic request)\n"           \
    "                        (minimum: 0, max: " MAX_REQUEST_SIZE_STR ")\n"  \
    "                        If 0, in the first exchange only an empty\n"    \
    "                        application data message is sent followed by\n" \
    "                        a second non-empty message before attempting\n" \
    "                        to read a response from the server\n"           \
    "    debug_level=%%d      default: 0 (disabled)\n"             \
    "    nbio=%%d             default: 0 (blocking I/O)\n"         \
    "                        options: 1 (non-blocking), 2 (added delays)\n"   \
    "    event=%%d            default: 0 (loop)\n"                            \
    "                        options: 1 (level-triggered, implies nbio=1),\n" \
    "    read_timeout=%%d     default: 0 ms (no timeout)\n"        \
    "    max_resend=%%d       default: 0 (no resend on timeout)\n" \
    "    skip_close_notify=%%d default: 0 (send close_notify)\n" \
    "\n"                                                    \
    USAGE_DTLS                                              \
    USAGE_CID                                               \
    USAGE_SRTP                                              \
    "\n"
#define USAGE2 \
    "    auth_mode=%%s        default: (library default: none)\n" \
    "                        options: none, optional, required\n" \
    USAGE_IO                                                \
    USAGE_KEY_OPAQUE                                        \
    USAGE_CA_CALLBACK                                       \
    "\n"                                                    \
    USAGE_PSK                                               \
    USAGE_ECJPAKE                                           \
    USAGE_ECRESTART                                         \
    "\n"
#define USAGE3 \
    "    allow_legacy=%%d     default: (library default: no)\n"   \
    USAGE_RENEGO                                            \
    "    exchanges=%%d        default: 1\n"                 \
    "    reconnect=%%d        number of reconnections using session resumption\n" \
    "                        default: 0 (disabled)\n"      \
    "    reco_delay=%%d       default: 0 seconds\n"         \
    "    reco_mode=%%d        0: copy session, 1: serialize session\n" \
    "                        default: 1\n"      \
    "    reconnect_hard=%%d   default: 0 (disabled)\n"      \
    USAGE_TICKETS                                           \
    USAGE_EAP_TLS                                           \
    USAGE_MAX_FRAG_LEN                                      \
    USAGE_CONTEXT_CRT_CB                                    \
    USAGE_ALPN                                              \
    USAGE_EMS                                               \
    USAGE_ETM                                               \
    USAGE_REPRODUCIBLE                                      \
    USAGE_CURVES                                            \
    USAGE_SIG_ALGS                                         \
    USAGE_DHMLEN                                            \
    "\n"

#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
#define TLS1_3_VERSION_OPTIONS  ", tls1_3"
#else /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
#define TLS1_3_VERSION_OPTIONS  ""
#endif /* !MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */

#define USAGE4 \
    "    allow_sha1=%%d       default: 0\n"                                   \
    "    min_version=%%s      default: (library default: tls1_2)\n"           \
    "    max_version=%%s      default: (library default: tls1_2)\n"           \
    "    force_version=%%s    default: \"\" (none)\n"                         \
    "                        options: tls1_2, dtls1_2" TLS1_3_VERSION_OPTIONS \
    "\n\n"                                                                    \
    "    force_ciphersuite=<name>    default: all enabled\n"                  \
    USAGE_TLS13_KEY_EXCHANGE_MODES                                            \
    "    query_config=<name>         return 0 if the specified\n"             \
    "                                configuration macro is defined and 1\n"  \
    "                                otherwise. The expansion of the macro\n" \
    "                                is printed if it is defined\n"           \
    USAGE_SERIALIZATION                                                       \
    " acceptable ciphersuite names:\n"

#define ALPN_LIST_SIZE    10
#define CURVE_LIST_SIZE   20
#define SIG_ALG_LIST_SIZE  5

/*
 * global options
 */
struct options
{
    const char *server_name;    /* hostname of the server (client only)     */
    const char *server_addr;    /* address of the server (client only)      */
    const char *server_port;    /* port on which the ssl service runs       */
    int debug_level;            /* level of debugging                       */
    int nbio;                   /* should I/O be blocking?                  */
    int event;                  /* loop or event-driven IO? level or edge triggered? */
    uint32_t read_timeout;      /* timeout on mbedtls_ssl_read() in milliseconds     */
    int max_resend;             /* DTLS times to resend on read timeout     */
    const char *request_page;   /* page on server to request                */
    int request_size;           /* pad request with header to requested size */
    const char *ca_file;        /* the file with the CA certificate(s)      */
    const char *ca_path;        /* the path with the CA certificate(s) reside */
    const char *crt_file;       /* the file with the client certificate     */
    const char *key_file;       /* the file with the client key             */
    int key_opaque;             /* handle private key as if it were opaque  */
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    int psk_opaque;
#endif
#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
    int ca_callback;            /* Use callback for trusted certificate list */
#endif
    const char *key_pwd;        /* the password for the client key          */
    const char *psk;            /* the pre-shared key                       */
    const char *psk_identity;   /* the pre-shared key identity              */
    const char *ecjpake_pw;     /* the EC J-PAKE password                   */
    int ec_max_ops;             /* EC consecutive operations limit          */
    int force_ciphersuite[2];   /* protocol/ciphersuite to use, or all      */
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
    int tls13_kex_modes;        /* supported TLS 1.3 key exchange modes     */
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
    int renegotiation;          /* enable / disable renegotiation           */
    int allow_legacy;           /* allow legacy renegotiation               */
    int renegotiate;            /* attempt renegotiation?                   */
    int renego_delay;           /* delay before enforcing renegotiation     */
    int exchanges;              /* number of data exchanges                 */
    int min_version;            /* minimum protocol version accepted        */
    int max_version;            /* maximum protocol version accepted        */
    int allow_sha1;             /* flag for SHA-1 support                   */
    int auth_mode;              /* verify mode for connection               */
    unsigned char mfl_code;     /* code for maximum fragment length         */
    int trunc_hmac;             /* negotiate truncated hmac or not          */
    int recsplit;               /* enable record splitting?                 */
    int dhmlen;                 /* minimum DHM params len in bits           */
    int reconnect;              /* attempt to resume session                */
    int reco_delay;             /* delay in seconds before resuming session */
    int reco_mode;              /* how to keep the session around           */
    int reconnect_hard;         /* unexpectedly reconnect from the same port */
    int tickets;                /* enable / disable session tickets         */
    const char *curves;         /* list of supported elliptic curves        */
    const char *sig_algs;       /* supported TLS 1.3 signature algorithms   */
    const char *alpn_string;    /* ALPN supported protocols                 */
    int transport;              /* TLS or DTLS?                             */
    uint32_t hs_to_min;         /* Initial value of DTLS handshake timer    */
    uint32_t hs_to_max;         /* Max value of DTLS handshake timer        */
    int dtls_mtu;               /* UDP Maximum tranport unit for DTLS       */
    int fallback;               /* is this a fallback connection?           */
    int dgram_packing;          /* allow/forbid datagram packing            */
    int extended_ms;            /* negotiate extended master secret?        */
    int etm;                    /* negotiate encrypt then mac?              */
    int context_crt_cb;         /* use context-specific CRT verify callback */
    int eap_tls;                /* derive EAP-TLS keying material?          */
    int nss_keylog;             /* export NSS key log material              */
    const char *nss_keylog_file; /* NSS key log file                        */
    int cid_enabled;            /* whether to use the CID extension or not  */
    int cid_enabled_renego;     /* whether to use the CID extension or not
                                 * during renegotiation                     */
    const char *cid_val;        /* the CID to use for incoming messages     */
    int serialize;              /* serialize/deserialize connection         */
    const char *context_file;   /* the file to write a serialized connection
                                 * in the form of base64 code (serialize
                                 * option must be set)                      */
    const char *cid_val_renego; /* the CID to use for incoming messages
                                 * after renegotiation                      */
    int reproducible;           /* make communication reproducible          */
    int skip_close_notify;      /* skip sending the close_notify alert      */
    int query_config_mode;      /* whether to read config                   */
    int use_srtp;               /* Support SRTP                             */
    int force_srtp_profile;     /* SRTP protection profile to use or all    */
    const char *mki;            /* The dtls mki value to use                */
} opt;

#include "ssl_test_common_source.c"

#if defined(MBEDTLS_X509_CRT_PARSE_C)
static unsigned char peer_crt_info[1024];

/*
 * Enabled if debug_level > 1 in code below
 */
static int my_verify( void *data, mbedtls_x509_crt *crt,
                      int depth, uint32_t *flags )
{
    char buf[1024];
    ((void) data);

    mbedtls_printf( "\nVerify requested for (Depth %d):\n", depth );

#if !defined(MBEDTLS_X509_REMOVE_INFO)
    mbedtls_x509_crt_info( buf, sizeof( buf ) - 1, "", crt );
    if( depth == 0 )
        memcpy( peer_crt_info, buf, sizeof( buf ) );

    if( opt.debug_level == 0 )
        return( 0 );

    mbedtls_printf( "%s", buf );
#else
    ((void) crt);
    ((void) depth);
#endif

    if ( ( *flags ) == 0 )
        mbedtls_printf( "  This certificate has no flags\n" );
    else
    {
        x509_crt_verify_info( buf, sizeof( buf ), "  ! ", *flags );
        mbedtls_printf( "%s\n", buf );
    }

    return( 0 );
}
#endif /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
int report_cid_usage( mbedtls_ssl_context *ssl,
                      const char *additional_description )
{
    int ret;
    unsigned char peer_cid[ MBEDTLS_SSL_CID_OUT_LEN_MAX ];
    size_t peer_cid_len;
    int cid_negotiated;

    if( opt.transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM )
        return( 0 );

    /* Check if the use of a CID has been negotiated,
     * but don't ask for the CID value and length.
     *
     * Note: Here and below, we're demonstrating the various ways
     *       in which mbedtls_ssl_get_peer_cid() can be called,
     *       depending on whether or not the length/value of the
     *       peer's CID is needed.
     *
     *       An actual application, however, should use
     *       just one call to mbedtls_ssl_get_peer_cid(). */
    ret = mbedtls_ssl_get_peer_cid( ssl, &cid_negotiated,
                                    NULL, NULL );
    if( ret != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_ssl_get_peer_cid returned -0x%x\n\n",
                        (unsigned int) -ret );
        return( ret );
    }

    if( cid_negotiated == MBEDTLS_SSL_CID_DISABLED )
    {
        if( opt.cid_enabled == MBEDTLS_SSL_CID_ENABLED )
        {
            mbedtls_printf( "(%s) Use of Connection ID was rejected by the server.\n",
                            additional_description );
        }
    }
    else
    {
        size_t idx=0;
        mbedtls_printf( "(%s) Use of Connection ID has been negotiated.\n",
                        additional_description );

        /* Ask for just the length of the peer's CID. */
        ret = mbedtls_ssl_get_peer_cid( ssl, &cid_negotiated,
                                        NULL, &peer_cid_len );
        if( ret != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_get_peer_cid returned -0x%x\n\n",
                            (unsigned int) -ret );
            return( ret );
        }

        /* Ask for just length + value of the peer's CID. */
        ret = mbedtls_ssl_get_peer_cid( ssl, &cid_negotiated,
                                        peer_cid, &peer_cid_len );
        if( ret != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_get_peer_cid returned -0x%x\n\n",
                            (unsigned int) -ret );
            return( ret );
        }
        mbedtls_printf( "(%s) Peer CID (length %u Bytes): ",
                        additional_description,
                        (unsigned) peer_cid_len );
        while( idx < peer_cid_len )
        {
            mbedtls_printf( "%02x ", peer_cid[ idx ] );
            idx++;
        }
        mbedtls_printf( "\n" );
    }

    return( 0 );
}
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */

int main( int argc, char *argv[] )
{
    int ret = 0, len, tail_len, i, written, frags, retry_left;
    int query_config_ret = 0;
    mbedtls_net_context server_fd;
    io_ctx_t io_ctx;

#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) && \
    defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
    uint16_t sig_alg_list[SIG_ALG_LIST_SIZE];
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL &&
          MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */

    unsigned char buf[MAX_REQUEST_SIZE + 1];

#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
    unsigned char psk[MBEDTLS_PSK_MAX_LEN];
    size_t psk_len = 0;
#endif

#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
    unsigned char cid[MBEDTLS_SSL_CID_IN_LEN_MAX];
    unsigned char cid_renego[MBEDTLS_SSL_CID_IN_LEN_MAX];
    size_t cid_len = 0;
    size_t cid_renego_len = 0;
#endif

#if defined(MBEDTLS_SSL_ALPN)
    const char *alpn_list[ALPN_LIST_SIZE];
#endif

#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
    unsigned char alloc_buf[MEMORY_HEAP_SIZE];
#endif

#if defined(MBEDTLS_ECP_C)
    uint16_t group_list[CURVE_LIST_SIZE];
    const mbedtls_ecp_curve_info *curve_cur;
#endif
#if defined(MBEDTLS_SSL_DTLS_SRTP)
    unsigned char mki[MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH];
    size_t mki_len=0;
#endif

    const char *pers = "ssl_client2";

#if defined(MBEDTLS_USE_PSA_CRYPTO)
    psa_key_id_t slot = 0;
    psa_algorithm_t alg = 0;
    psa_key_attributes_t key_attributes;
    psa_status_t status;
#endif

#if defined(MBEDTLS_X509_CRT_PARSE_C)
    mbedtls_x509_crt_profile crt_profile_for_test = mbedtls_x509_crt_profile_default;
#endif
    rng_context_t rng;
    mbedtls_ssl_context ssl;
    mbedtls_ssl_config conf;
    mbedtls_ssl_session saved_session;
    unsigned char *session_data = NULL;
    size_t session_data_len = 0;
#if defined(MBEDTLS_TIMING_C)
    mbedtls_timing_delay_context timer;
#endif
#if defined(MBEDTLS_X509_CRT_PARSE_C)
    uint32_t flags;
    mbedtls_x509_crt cacert;
    mbedtls_x509_crt clicert;
    mbedtls_pk_context pkey;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    psa_key_id_t key_slot = 0; /* invalid key slot */
#endif
#endif  /* MBEDTLS_X509_CRT_PARSE_C */
    char *p, *q;
    const int *list;
#if defined(MBEDTLS_SSL_CONTEXT_SERIALIZATION)
    unsigned char *context_buf = NULL;
    size_t context_buf_len;
#endif
    unsigned char eap_tls_keymaterial[16];
    unsigned char eap_tls_iv[8];
    const char* eap_tls_label = "client EAP encryption";
    eap_tls_keys eap_tls_keying;
#if defined( MBEDTLS_SSL_DTLS_SRTP )
    /*! master keys and master salt for SRTP generated during handshake */
    unsigned char dtls_srtp_key_material[MBEDTLS_TLS_SRTP_MAX_KEY_MATERIAL_LENGTH];
    const char* dtls_srtp_label = "EXTRACTOR-dtls_srtp";
    dtls_srtp_keys dtls_srtp_keying;
    const mbedtls_ssl_srtp_profile default_profiles[] = {
        MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_80,
        MBEDTLS_TLS_SRTP_AES128_CM_HMAC_SHA1_32,
        MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_80,
        MBEDTLS_TLS_SRTP_NULL_HMAC_SHA1_32,
        MBEDTLS_TLS_SRTP_UNSET
    };
#endif /* MBEDTLS_SSL_DTLS_SRTP */

#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
    mbedtls_memory_buffer_alloc_init( alloc_buf, sizeof(alloc_buf) );
#endif

#if defined(MBEDTLS_TEST_HOOKS)
    test_hooks_init( );
#endif /* MBEDTLS_TEST_HOOKS */

    /*
     * Make sure memory references are valid.
     */
    mbedtls_net_init( &server_fd );
    mbedtls_ssl_init( &ssl );
    mbedtls_ssl_config_init( &conf );
    memset( &saved_session, 0, sizeof( mbedtls_ssl_session ) );
    rng_init( &rng );
#if defined(MBEDTLS_X509_CRT_PARSE_C)
    mbedtls_x509_crt_init( &cacert );
    mbedtls_x509_crt_init( &clicert );
    mbedtls_pk_init( &pkey );
#endif
#if defined(MBEDTLS_SSL_ALPN)
    memset( (void * ) alpn_list, 0, sizeof( alpn_list ) );
#endif

#if defined(MBEDTLS_USE_PSA_CRYPTO)
    status = psa_crypto_init();
    if( status != PSA_SUCCESS )
    {
        mbedtls_fprintf( stderr, "Failed to initialize PSA Crypto implementation: %d\n",
                         (int) status );
        ret = MBEDTLS_ERR_SSL_HW_ACCEL_FAILED;
        goto exit;
    }
#endif  /* MBEDTLS_USE_PSA_CRYPTO */
#if defined(MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG)
    mbedtls_test_enable_insecure_external_rng( );
#endif  /* MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */

    if( argc == 0 )
    {
    usage:
        if( ret == 0 )
            ret = 1;

        mbedtls_printf( USAGE1 );
        mbedtls_printf( USAGE2 );
        mbedtls_printf( USAGE3 );
        mbedtls_printf( USAGE4 );

        list = mbedtls_ssl_list_ciphersuites();
        while( *list )
        {
            mbedtls_printf(" %-42s", mbedtls_ssl_get_ciphersuite_name( *list ) );
            list++;
            if( !*list )
                break;
            mbedtls_printf(" %s\n", mbedtls_ssl_get_ciphersuite_name( *list ) );
            list++;
        }
        mbedtls_printf("\n");
        goto exit;
    }

    opt.server_name         = DFL_SERVER_NAME;
    opt.server_addr         = DFL_SERVER_ADDR;
    opt.server_port         = DFL_SERVER_PORT;
    opt.debug_level         = DFL_DEBUG_LEVEL;
    opt.cid_enabled         = DFL_CID_ENABLED;
    opt.cid_val             = DFL_CID_VALUE;
    opt.cid_enabled_renego  = DFL_CID_ENABLED_RENEGO;
    opt.cid_val_renego      = DFL_CID_VALUE_RENEGO;
    opt.nbio                = DFL_NBIO;
    opt.event               = DFL_EVENT;
    opt.context_crt_cb      = DFL_CONTEXT_CRT_CB;
    opt.read_timeout        = DFL_READ_TIMEOUT;
    opt.max_resend          = DFL_MAX_RESEND;
    opt.request_page        = DFL_REQUEST_PAGE;
    opt.request_size        = DFL_REQUEST_SIZE;
    opt.ca_file             = DFL_CA_FILE;
    opt.ca_path             = DFL_CA_PATH;
    opt.crt_file            = DFL_CRT_FILE;
    opt.key_file            = DFL_KEY_FILE;
    opt.key_opaque          = DFL_KEY_OPAQUE;
    opt.key_pwd             = DFL_KEY_PWD;
    opt.psk                 = DFL_PSK;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    opt.psk_opaque          = DFL_PSK_OPAQUE;
#endif
#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
    opt.ca_callback         = DFL_CA_CALLBACK;
#endif
    opt.psk_identity        = DFL_PSK_IDENTITY;
    opt.ecjpake_pw          = DFL_ECJPAKE_PW;
    opt.ec_max_ops          = DFL_EC_MAX_OPS;
    opt.force_ciphersuite[0]= DFL_FORCE_CIPHER;
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
    opt.tls13_kex_modes     = DFL_TLS13_KEX_MODES;
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
    opt.renegotiation       = DFL_RENEGOTIATION;
    opt.allow_legacy        = DFL_ALLOW_LEGACY;
    opt.renegotiate         = DFL_RENEGOTIATE;
    opt.exchanges           = DFL_EXCHANGES;
    opt.min_version         = DFL_MIN_VERSION;
    opt.max_version         = DFL_MAX_VERSION;
    opt.allow_sha1          = DFL_SHA1;
    opt.auth_mode           = DFL_AUTH_MODE;
    opt.mfl_code            = DFL_MFL_CODE;
    opt.trunc_hmac          = DFL_TRUNC_HMAC;
    opt.recsplit            = DFL_RECSPLIT;
    opt.dhmlen              = DFL_DHMLEN;
    opt.reconnect           = DFL_RECONNECT;
    opt.reco_delay          = DFL_RECO_DELAY;
    opt.reco_mode           = DFL_RECO_MODE;
    opt.reconnect_hard      = DFL_RECONNECT_HARD;
    opt.tickets             = DFL_TICKETS;
    opt.alpn_string         = DFL_ALPN_STRING;
    opt.curves              = DFL_CURVES;
    opt.sig_algs            = DFL_SIG_ALGS;
    opt.transport           = DFL_TRANSPORT;
    opt.hs_to_min           = DFL_HS_TO_MIN;
    opt.hs_to_max           = DFL_HS_TO_MAX;
    opt.dtls_mtu            = DFL_DTLS_MTU;
    opt.fallback            = DFL_FALLBACK;
    opt.extended_ms         = DFL_EXTENDED_MS;
    opt.etm                 = DFL_ETM;
    opt.dgram_packing       = DFL_DGRAM_PACKING;
    opt.serialize           = DFL_SERIALIZE;
    opt.context_file        = DFL_CONTEXT_FILE;
    opt.eap_tls             = DFL_EAP_TLS;
    opt.reproducible        = DFL_REPRODUCIBLE;
    opt.nss_keylog          = DFL_NSS_KEYLOG;
    opt.nss_keylog_file     = DFL_NSS_KEYLOG_FILE;
    opt.skip_close_notify   = DFL_SKIP_CLOSE_NOTIFY;
    opt.query_config_mode   = DFL_QUERY_CONFIG_MODE;
    opt.use_srtp            = DFL_USE_SRTP;
    opt.force_srtp_profile  = DFL_SRTP_FORCE_PROFILE;
    opt.mki                 = DFL_SRTP_MKI;

    for( i = 1; i < argc; i++ )
    {
        p = argv[i];
        if( ( q = strchr( p, '=' ) ) == NULL )
            goto usage;
        *q++ = '\0';

        if( strcmp( p, "server_name" ) == 0 )
            opt.server_name = q;
        else if( strcmp( p, "server_addr" ) == 0 )
            opt.server_addr = q;
        else if( strcmp( p, "server_port" ) == 0 )
            opt.server_port = q;
        else if( strcmp( p, "dtls" ) == 0 )
        {
            int t = atoi( q );
            if( t == 0 )
                opt.transport = MBEDTLS_SSL_TRANSPORT_STREAM;
            else if( t == 1 )
                opt.transport = MBEDTLS_SSL_TRANSPORT_DATAGRAM;
            else
                goto usage;
        }
        else if( strcmp( p, "debug_level" ) == 0 )
        {
            opt.debug_level = atoi( q );
            if( opt.debug_level < 0 || opt.debug_level > 65535 )
                goto usage;
        }
        else if( strcmp( p, "context_crt_cb" ) == 0 )
        {
            opt.context_crt_cb = atoi( q );
            if( opt.context_crt_cb != 0 && opt.context_crt_cb != 1 )
                goto usage;
        }
        else if( strcmp( p, "nbio" ) == 0 )
        {
            opt.nbio = atoi( q );
            if( opt.nbio < 0 || opt.nbio > 2 )
                goto usage;
        }
        else if( strcmp( p, "event" ) == 0 )
        {
            opt.event = atoi( q );
            if( opt.event < 0 || opt.event > 2 )
                goto usage;
        }
        else if( strcmp( p, "read_timeout" ) == 0 )
            opt.read_timeout = atoi( q );
        else if( strcmp( p, "max_resend" ) == 0 )
        {
            opt.max_resend = atoi( q );
            if( opt.max_resend < 0 )
                goto usage;
        }
        else if( strcmp( p, "request_page" ) == 0 )
            opt.request_page = q;
        else if( strcmp( p, "request_size" ) == 0 )
        {
            opt.request_size = atoi( q );
            if( opt.request_size < 0 ||
                opt.request_size > MAX_REQUEST_SIZE )
                goto usage;
        }
        else if( strcmp( p, "ca_file" ) == 0 )
            opt.ca_file = q;
        else if( strcmp( p, "ca_path" ) == 0 )
            opt.ca_path = q;
        else if( strcmp( p, "crt_file" ) == 0 )
            opt.crt_file = q;
        else if( strcmp( p, "key_file" ) == 0 )
            opt.key_file = q;
        else if( strcmp( p, "key_pwd" ) == 0 )
            opt.key_pwd = q;
#if defined(MBEDTLS_USE_PSA_CRYPTO) && defined(MBEDTLS_X509_CRT_PARSE_C)
        else if( strcmp( p, "key_opaque" ) == 0 )
            opt.key_opaque = atoi( q );
#endif
#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
        else if( strcmp( p, "cid" ) == 0 )
        {
            opt.cid_enabled = atoi( q );
            if( opt.cid_enabled != 0 && opt.cid_enabled != 1 )
                goto usage;
        }
        else if( strcmp( p, "cid_renego" ) == 0 )
        {
            opt.cid_enabled_renego = atoi( q );
            if( opt.cid_enabled_renego != 0 && opt.cid_enabled_renego != 1 )
                goto usage;
        }
        else if( strcmp( p, "cid_val" ) == 0 )
        {
            opt.cid_val = q;
        }
        else if( strcmp( p, "cid_val_renego" ) == 0 )
        {
            opt.cid_val_renego = q;
        }
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */
        else if( strcmp( p, "psk" ) == 0 )
            opt.psk = q;
#if defined(MBEDTLS_USE_PSA_CRYPTO)
        else if( strcmp( p, "psk_opaque" ) == 0 )
            opt.psk_opaque = atoi( q );
#endif
#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
        else if( strcmp( p, "ca_callback" ) == 0)
            opt.ca_callback = atoi( q );
#endif
        else if( strcmp( p, "psk_identity" ) == 0 )
            opt.psk_identity = q;
        else if( strcmp( p, "ecjpake_pw" ) == 0 )
            opt.ecjpake_pw = q;
        else if( strcmp( p, "ec_max_ops" ) == 0 )
            opt.ec_max_ops = atoi( q );
        else if( strcmp( p, "force_ciphersuite" ) == 0 )
        {
            opt.force_ciphersuite[0] = mbedtls_ssl_get_ciphersuite_id( q );

            if( opt.force_ciphersuite[0] == 0 )
            {
                ret = 2;
                goto usage;
            }
            opt.force_ciphersuite[1] = 0;
        }
        else if( strcmp( p, "renegotiation" ) == 0 )
        {
            opt.renegotiation = (atoi( q )) ?
                MBEDTLS_SSL_RENEGOTIATION_ENABLED :
                MBEDTLS_SSL_RENEGOTIATION_DISABLED;
        }
        else if( strcmp( p, "allow_legacy" ) == 0 )
        {
            switch( atoi( q ) )
            {
                case -1:
                    opt.allow_legacy = MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE;
                    break;
                case 0:
                    opt.allow_legacy = MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION;
                    break;
                case 1:
                    opt.allow_legacy = MBEDTLS_SSL_LEGACY_ALLOW_RENEGOTIATION;
                    break;
                default: goto usage;
            }
        }
        else if( strcmp( p, "renegotiate" ) == 0 )
        {
            opt.renegotiate = atoi( q );
            if( opt.renegotiate < 0 || opt.renegotiate > 1 )
                goto usage;
        }
        else if( strcmp( p, "exchanges" ) == 0 )
        {
            opt.exchanges = atoi( q );
            if( opt.exchanges < 1 )
                goto usage;
        }
        else if( strcmp( p, "reconnect" ) == 0 )
        {
            opt.reconnect = atoi( q );
            if( opt.reconnect < 0 || opt.reconnect > 2 )
                goto usage;
        }
        else if( strcmp( p, "reco_delay" ) == 0 )
        {
            opt.reco_delay = atoi( q );
            if( opt.reco_delay < 0 )
                goto usage;
        }
        else if( strcmp( p, "reco_mode" ) == 0 )
        {
            opt.reco_mode = atoi( q );
            if( opt.reco_mode < 0 )
                goto usage;
        }
        else if( strcmp( p, "reconnect_hard" ) == 0 )
        {
            opt.reconnect_hard = atoi( q );
            if( opt.reconnect_hard < 0 || opt.reconnect_hard > 1 )
                goto usage;
        }
        else if( strcmp( p, "tickets" ) == 0 )
        {
            opt.tickets = atoi( q );
            if( opt.tickets < 0 || opt.tickets > 2 )
                goto usage;
        }
        else if( strcmp( p, "alpn" ) == 0 )
        {
            opt.alpn_string = q;
        }
        else if( strcmp( p, "extended_ms" ) == 0 )
        {
            switch( atoi( q ) )
            {
                case 0:
                    opt.extended_ms = MBEDTLS_SSL_EXTENDED_MS_DISABLED;
                    break;
                case 1:
                    opt.extended_ms = MBEDTLS_SSL_EXTENDED_MS_ENABLED;
                    break;
                default: goto usage;
            }
        }
        else if( strcmp( p, "curves" ) == 0 )
            opt.curves = q;
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) && \
    defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
        else if( strcmp( p, "sig_algs" ) == 0 )
            opt.sig_algs = q;
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL &&
          MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
        else if( strcmp( p, "etm" ) == 0 )
        {
            switch( atoi( q ) )
            {
                case 0: opt.etm = MBEDTLS_SSL_ETM_DISABLED; break;
                case 1: opt.etm = MBEDTLS_SSL_ETM_ENABLED; break;
                default: goto usage;
            }
        }
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
        else if( strcmp( p, "tls13_kex_modes" ) == 0 )
        {
            if( strcmp( q, "psk" ) == 0 )
                opt.tls13_kex_modes = MBEDTLS_SSL_TLS13_KEY_EXCHANGE_MODE_PSK;
            else if( strcmp(q, "psk_ephemeral" ) == 0 )
                opt.tls13_kex_modes = MBEDTLS_SSL_TLS13_KEY_EXCHANGE_MODE_PSK_EPHEMERAL;
            else if( strcmp(q, "ephemeral" ) == 0 )
                opt.tls13_kex_modes = MBEDTLS_SSL_TLS13_KEY_EXCHANGE_MODE_EPHEMERAL;
            else if( strcmp(q, "ephemeral_all" ) == 0 )
                opt.tls13_kex_modes = MBEDTLS_SSL_TLS13_KEY_EXCHANGE_MODE_EPHEMERAL_ALL;
            else if( strcmp( q, "psk_all" ) == 0 )
                opt.tls13_kex_modes = MBEDTLS_SSL_TLS13_KEY_EXCHANGE_MODE_PSK_ALL;
            else if( strcmp( q, "all" ) == 0 )
                opt.tls13_kex_modes = MBEDTLS_SSL_TLS13_KEY_EXCHANGE_MODE_ALL;
            else goto usage;
        }
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
        else if( strcmp( p, "min_version" ) == 0 )
        {
            if( strcmp( q, "tls1_2" ) == 0 ||
                     strcmp( q, "dtls1_2" ) == 0 )
                opt.min_version = MBEDTLS_SSL_MINOR_VERSION_3;
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
            else if( strcmp( q, "tls1_3" ) == 0 )
                opt.min_version = MBEDTLS_SSL_MINOR_VERSION_4;
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
            else
                goto usage;
        }
        else if( strcmp( p, "max_version" ) == 0 )
        {
            if( strcmp( q, "tls1_2" ) == 0 ||
                     strcmp( q, "dtls1_2" ) == 0 )
                opt.max_version = MBEDTLS_SSL_MINOR_VERSION_3;
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
            else if( strcmp( q, "tls1_3" ) == 0 )
                opt.max_version = MBEDTLS_SSL_MINOR_VERSION_4;
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
            else
                goto usage;
        }
        else if( strcmp( p, "allow_sha1" ) == 0 )
        {
            switch( atoi( q ) )
            {
                case 0:     opt.allow_sha1 = 0;   break;
                case 1:     opt.allow_sha1 = 1;    break;
                default:    goto usage;
            }
        }
        else if( strcmp( p, "force_version" ) == 0 )
        {
            if( strcmp( q, "tls1_2" ) == 0 )
            {
                opt.min_version = MBEDTLS_SSL_MINOR_VERSION_3;
                opt.max_version = MBEDTLS_SSL_MINOR_VERSION_3;
            }
            else if( strcmp( q, "dtls1_2" ) == 0 )
            {
                opt.min_version = MBEDTLS_SSL_MINOR_VERSION_3;
                opt.max_version = MBEDTLS_SSL_MINOR_VERSION_3;
                opt.transport = MBEDTLS_SSL_TRANSPORT_DATAGRAM;
            }
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
            else if( strcmp( q, "tls1_3" ) == 0 )
            {
                opt.min_version = MBEDTLS_SSL_MINOR_VERSION_4;
                opt.max_version = MBEDTLS_SSL_MINOR_VERSION_4;
            }
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
            else
                goto usage;
        }
        else if( strcmp( p, "auth_mode" ) == 0 )
        {
            if( strcmp( q, "none" ) == 0 )
                opt.auth_mode = MBEDTLS_SSL_VERIFY_NONE;
            else if( strcmp( q, "optional" ) == 0 )
                opt.auth_mode = MBEDTLS_SSL_VERIFY_OPTIONAL;
            else if( strcmp( q, "required" ) == 0 )
                opt.auth_mode = MBEDTLS_SSL_VERIFY_REQUIRED;
            else
                goto usage;
        }
        else if( strcmp( p, "max_frag_len" ) == 0 )
        {
            if( strcmp( q, "512" ) == 0 )
                opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_512;
            else if( strcmp( q, "1024" ) == 0 )
                opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_1024;
            else if( strcmp( q, "2048" ) == 0 )
                opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_2048;
            else if( strcmp( q, "4096" ) == 0 )
                opt.mfl_code = MBEDTLS_SSL_MAX_FRAG_LEN_4096;
            else
                goto usage;
        }
        else if( strcmp( p, "trunc_hmac" ) == 0 )
        {
            switch( atoi( q ) )
            {
                case 0: opt.trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_DISABLED; break;
                case 1: opt.trunc_hmac = MBEDTLS_SSL_TRUNC_HMAC_ENABLED; break;
                default: goto usage;
            }
        }
        else if( strcmp( p, "hs_timeout" ) == 0 )
        {
            if( ( p = strchr( q, '-' ) ) == NULL )
                goto usage;
            *p++ = '\0';
            opt.hs_to_min = atoi( q );
            opt.hs_to_max = atoi( p );
            if( opt.hs_to_min == 0 || opt.hs_to_max < opt.hs_to_min )
                goto usage;
        }
        else if( strcmp( p, "mtu" ) == 0 )
        {
            opt.dtls_mtu = atoi( q );
            if( opt.dtls_mtu < 0 )
                goto usage;
        }
        else if( strcmp( p, "dgram_packing" ) == 0 )
        {
            opt.dgram_packing = atoi( q );
            if( opt.dgram_packing != 0 &&
                opt.dgram_packing != 1 )
            {
                goto usage;
            }
        }
        else if( strcmp( p, "recsplit" ) == 0 )
        {
            opt.recsplit = atoi( q );
            if( opt.recsplit < 0 || opt.recsplit > 1 )
                goto usage;
        }
        else if( strcmp( p, "dhmlen" ) == 0 )
        {
            opt.dhmlen = atoi( q );
            if( opt.dhmlen < 0 )
                goto usage;
        }
        else if( strcmp( p, "query_config" ) == 0 )
        {
            opt.query_config_mode = 1;
            query_config_ret = query_config( q );
            goto exit;
        }
        else if( strcmp( p, "serialize") == 0 )
        {
            opt.serialize = atoi( q );
            if( opt.serialize < 0 || opt.serialize > 2)
                goto usage;
        }
        else if( strcmp( p, "context_file") == 0 )
        {
            opt.context_file = q;
        }
        else if( strcmp( p, "eap_tls" ) == 0 )
        {
            opt.eap_tls = atoi( q );
            if( opt.eap_tls < 0 || opt.eap_tls > 1 )
                goto usage;
        }
        else if( strcmp( p, "reproducible" ) == 0 )
        {
            opt.reproducible = 1;
        }
        else if( strcmp( p, "nss_keylog" ) == 0 )
        {
            opt.nss_keylog = atoi( q );
            if( opt.nss_keylog < 0 || opt.nss_keylog > 1 )
                goto usage;
        }
        else if( strcmp( p, "nss_keylog_file" ) == 0 )
        {
            opt.nss_keylog_file = q;
        }
        else if( strcmp( p, "skip_close_notify" ) == 0 )
        {
            opt.skip_close_notify = atoi( q );
            if( opt.skip_close_notify < 0 || opt.skip_close_notify > 1 )
                goto usage;
        }
        else if( strcmp( p, "use_srtp" ) == 0 )
        {
            opt.use_srtp = atoi ( q );
        }
        else if( strcmp( p, "srtp_force_profile" ) == 0 )
        {
            opt.force_srtp_profile = atoi( q );
        }
        else if( strcmp( p, "mki" ) == 0 )
        {
            opt.mki = q;
        }
        else
            goto usage;
    }

    if( opt.nss_keylog != 0 && opt.eap_tls != 0 )
    {
        mbedtls_printf( "Error: eap_tls and nss_keylog options cannot be used together.\n" );
        goto usage;
    }

    /* Event-driven IO is incompatible with the above custom
     * receive and send functions, as the polling builds on
     * refers to the underlying net_context. */
    if( opt.event == 1 && opt.nbio != 1 )
    {
        mbedtls_printf( "Warning: event-driven IO mandates nbio=1 - overwrite\n" );
        opt.nbio = 1;
    }

#if defined(MBEDTLS_DEBUG_C)
    mbedtls_debug_set_threshold( opt.debug_level );
#endif

#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
    /*
     * Unhexify the pre-shared key if any is given
     */
    if( strlen( opt.psk ) )
    {
        if( mbedtls_test_unhexify( psk, sizeof( psk ),
                                   opt.psk, &psk_len ) != 0 )
        {
            mbedtls_printf( "pre-shared key not valid\n" );
            goto exit;
        }
    }
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */

#if defined(MBEDTLS_USE_PSA_CRYPTO)
    if( opt.psk_opaque != 0 )
    {
        if( opt.psk == NULL )
        {
            mbedtls_printf( "psk_opaque set but no psk to be imported specified.\n" );
            ret = 2;
            goto usage;
        }

        if( opt.force_ciphersuite[0] <= 0 )
        {
            mbedtls_printf( "opaque PSKs are only supported in conjunction with forcing TLS 1.2 and a PSK-only ciphersuite through the 'force_ciphersuite' option.\n" );
            ret = 2;
            goto usage;
        }
    }
#endif /* MBEDTLS_USE_PSA_CRYPTO */

    if( opt.force_ciphersuite[0] > 0 )
    {
        const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
        ciphersuite_info =
            mbedtls_ssl_ciphersuite_from_id( opt.force_ciphersuite[0] );

        if( opt.max_version != -1 &&
            ciphersuite_info->min_minor_ver > opt.max_version )
        {
            mbedtls_printf( "forced ciphersuite not allowed with this protocol version\n" );
            ret = 2;
            goto usage;
        }
        if( opt.min_version != -1 &&
            ciphersuite_info->max_minor_ver < opt.min_version )
        {
            mbedtls_printf( "forced ciphersuite not allowed with this protocol version\n" );
            ret = 2;
            goto usage;
        }

        /* If the server selects a version that's not supported by
         * this suite, then there will be no common ciphersuite... */
        if( opt.max_version == -1 ||
            opt.max_version > ciphersuite_info->max_minor_ver )
        {
            opt.max_version = ciphersuite_info->max_minor_ver;
        }
        if( opt.min_version < ciphersuite_info->min_minor_ver )
        {
            opt.min_version = ciphersuite_info->min_minor_ver;
            /* DTLS starts with TLS 1.2 */
            if( opt.transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
                opt.min_version < MBEDTLS_SSL_MINOR_VERSION_3 )
                opt.min_version = MBEDTLS_SSL_MINOR_VERSION_3;
        }

#if defined(MBEDTLS_USE_PSA_CRYPTO)
        if( opt.psk_opaque != 0 )
        {
            /* Ensure that the chosen ciphersuite is PSK-only; we must know
             * the ciphersuite in advance to set the correct policy for the
             * PSK key slot. This limitation might go away in the future. */
            if( ciphersuite_info->key_exchange != MBEDTLS_KEY_EXCHANGE_PSK ||
                opt.min_version != MBEDTLS_SSL_MINOR_VERSION_3 )
            {
                mbedtls_printf( "opaque PSKs are only supported in conjunction with forcing TLS 1.2 and a PSK-only ciphersuite through the 'force_ciphersuite' option.\n" );
                ret = 2;
                goto usage;
            }

            /* Determine KDF algorithm the opaque PSK will be used in. */
#if defined(MBEDTLS_SHA384_C)
            if( ciphersuite_info->mac == MBEDTLS_MD_SHA384 )
                alg = PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_384);
            else
#endif /* MBEDTLS_SHA384_C */
                alg = PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_256);
        }
#endif /* MBEDTLS_USE_PSA_CRYPTO */
    }

#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
    if( mbedtls_test_unhexify( cid, sizeof( cid ),
                               opt.cid_val, &cid_len ) != 0 )
    {
        mbedtls_printf( "CID not valid\n" );
        goto exit;
    }

    /* Keep CID settings for renegotiation unless
     * specified otherwise. */
    if( opt.cid_enabled_renego == DFL_CID_ENABLED_RENEGO )
        opt.cid_enabled_renego = opt.cid_enabled;
    if( opt.cid_val_renego == DFL_CID_VALUE_RENEGO )
        opt.cid_val_renego = opt.cid_val;

    if( mbedtls_test_unhexify( cid_renego, sizeof( cid_renego ),
                               opt.cid_val_renego, &cid_renego_len ) != 0 )
    {
        mbedtls_printf( "CID not valid\n" );
        goto exit;
    }
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */

#if defined(MBEDTLS_ECP_C)
    if( opt.curves != NULL )
    {
        p = (char *) opt.curves;
        i = 0;

        if( strcmp( p, "none" ) == 0 )
        {
            group_list[0] = 0;
        }
        else if( strcmp( p, "default" ) != 0 )
        {
            /* Leave room for a final NULL in curve list */
            while( i < CURVE_LIST_SIZE - 1 && *p != '\0' )
            {
                q = p;

                /* Terminate the current string */
                while( *p != ',' && *p != '\0' )
                    p++;
                if( *p == ',' )
                    *p++ = '\0';

                if( ( curve_cur = mbedtls_ecp_curve_info_from_name( q ) ) != NULL )
                {
                    group_list[i++] = curve_cur->tls_id;
                }
                else
                {
                    mbedtls_printf( "unknown curve %s\n", q );
                    mbedtls_printf( "supported curves: " );
                    for( curve_cur = mbedtls_ecp_curve_list();
                         curve_cur->grp_id != MBEDTLS_ECP_DP_NONE;
                         curve_cur++ )
                    {
                        mbedtls_printf( "%s ", curve_cur->name );
                    }
                    mbedtls_printf( "\n" );
                    goto exit;
                }
            }

            mbedtls_printf("Number of curves: %d\n", i );

            if( i == CURVE_LIST_SIZE - 1 && *p != '\0' )
            {
                mbedtls_printf( "curves list too long, maximum %d",
                                CURVE_LIST_SIZE - 1 );
                goto exit;
            }

            group_list[i] = 0;
        }
    }
#endif /* MBEDTLS_ECP_C */

#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL) && \
    defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
    if( opt.sig_algs != NULL )
    {
        p = (char *) opt.sig_algs;
        i = 0;

        /* Leave room for a final MBEDTLS_TLS13_SIG_NONE in signature algorithm list (sig_alg_list). */
        while( i < SIG_ALG_LIST_SIZE - 1 && *p != '\0' )
        {
            q = p;

            /* Terminate the current string */
            while( *p != ',' && *p != '\0' )
                p++;
            if( *p == ',' )
                *p++ = '\0';

            if( strcmp( q, "ecdsa_secp256r1_sha256" ) == 0 )
            {
                sig_alg_list[i++] = MBEDTLS_TLS13_SIG_ECDSA_SECP256R1_SHA256;
            }
            else if( strcmp( q, "ecdsa_secp384r1_sha384" ) == 0 )
            {
                sig_alg_list[i++] = MBEDTLS_TLS13_SIG_ECDSA_SECP384R1_SHA384;
            }
            else if( strcmp( q, "ecdsa_secp521r1_sha512" ) == 0 )
            {
                sig_alg_list[i++] = MBEDTLS_TLS13_SIG_ECDSA_SECP521R1_SHA512;
            }
            else
            {
                mbedtls_printf( "unknown signature algorithm %s\n", q );
                mbedtls_printf( "supported signature algorithms: " );
                mbedtls_printf( "ecdsa_secp256r1_sha256 " );
                mbedtls_printf( "ecdsa_secp384r1_sha384 " );
                mbedtls_printf( "ecdsa_secp521r1_sha512 " );
                mbedtls_printf( "\n" );
                goto exit;
            }
        }

        if( i == ( SIG_ALG_LIST_SIZE - 1 ) && *p != '\0' )
        {
            mbedtls_printf( "signature algorithm list too long, maximum %d",
                            SIG_ALG_LIST_SIZE - 1 );
            goto exit;
        }

        sig_alg_list[i] = MBEDTLS_TLS13_SIG_NONE;
    }
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL &&
          MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */

#if defined(MBEDTLS_SSL_ALPN)
    if( opt.alpn_string != NULL )
    {
        p = (char *) opt.alpn_string;
        i = 0;

        /* Leave room for a final NULL in alpn_list */
        while( i < ALPN_LIST_SIZE - 1 && *p != '\0' )
        {
            alpn_list[i++] = p;

            /* Terminate the current string and move on to next one */
            while( *p != ',' && *p != '\0' )
                p++;
            if( *p == ',' )
                *p++ = '\0';
        }
    }
#endif /* MBEDTLS_SSL_ALPN */

    /*
     * 0. Initialize the RNG and the session data
     */
    mbedtls_printf( "\n  . Seeding the random number generator..." );
    fflush( stdout );

    ret = rng_seed( &rng, opt.reproducible, pers );
    if( ret != 0 )
        goto exit;
    mbedtls_printf( " ok\n" );

#if defined(MBEDTLS_X509_CRT_PARSE_C)
    /*
     * 1.1. Load the trusted CA
     */
    mbedtls_printf( "  . Loading the CA root certificate ..." );
    fflush( stdout );

    if( strcmp( opt.ca_path, "none" ) == 0 ||
        strcmp( opt.ca_file, "none" ) == 0 )
    {
        ret = 0;
    }
    else
#if defined(MBEDTLS_FS_IO)
    if( strlen( opt.ca_path ) )
        ret = mbedtls_x509_crt_parse_path( &cacert, opt.ca_path );
    else if( strlen( opt.ca_file ) )
        ret = mbedtls_x509_crt_parse_file( &cacert, opt.ca_file );
    else
#endif
    {
#if defined(MBEDTLS_PEM_PARSE_C)
        for( i = 0; mbedtls_test_cas[i] != NULL; i++ )
        {
            ret = mbedtls_x509_crt_parse( &cacert,
                                  (const unsigned char *) mbedtls_test_cas[i],
                                  mbedtls_test_cas_len[i] );
            if( ret != 0 )
                break;
        }
        if( ret == 0 )
#endif /* MBEDTLS_PEM_PARSE_C */
        for( i = 0; mbedtls_test_cas_der[i] != NULL; i++ )
        {
            ret = mbedtls_x509_crt_parse_der( &cacert,
                         (const unsigned char *) mbedtls_test_cas_der[i],
                         mbedtls_test_cas_der_len[i] );
            if( ret != 0 )
                break;
        }
    }
    if( ret < 0 )
    {
        mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse returned -0x%x\n\n",
                        (unsigned int) -ret );
        goto exit;
    }

    mbedtls_printf( " ok (%d skipped)\n", ret );

    /*
     * 1.2. Load own certificate and private key
     *
     * (can be skipped if client authentication is not required)
     */
    mbedtls_printf( "  . Loading the client cert. and key..." );
    fflush( stdout );

    if( strcmp( opt.crt_file, "none" ) == 0 )
        ret = 0;
    else
#if defined(MBEDTLS_FS_IO)
    if( strlen( opt.crt_file ) )
        ret = mbedtls_x509_crt_parse_file( &clicert, opt.crt_file );
    else
#endif
        ret = mbedtls_x509_crt_parse( &clicert,
                (const unsigned char *) mbedtls_test_cli_crt,
                mbedtls_test_cli_crt_len );
    if( ret != 0 )
    {
        mbedtls_printf( " failed\n  !  mbedtls_x509_crt_parse returned -0x%x\n\n",
                        (unsigned int) -ret );
        goto exit;
    }

    if( strcmp( opt.key_file, "none" ) == 0 )
        ret = 0;
    else
#if defined(MBEDTLS_FS_IO)
    if( strlen( opt.key_file ) )
        ret = mbedtls_pk_parse_keyfile( &pkey, opt.key_file, opt.key_pwd, rng_get, &rng );
    else
#endif
        ret = mbedtls_pk_parse_key( &pkey,
                (const unsigned char *) mbedtls_test_cli_key,
                mbedtls_test_cli_key_len, NULL, 0, rng_get, &rng );
    if( ret != 0 )
    {
        mbedtls_printf( " failed\n  !  mbedtls_pk_parse_key returned -0x%x\n\n",
                        (unsigned int) -ret );
        goto exit;
    }

#if defined(MBEDTLS_USE_PSA_CRYPTO)
    if( opt.key_opaque != 0 )
    {
        if( ( ret = mbedtls_pk_wrap_as_opaque( &pkey, &key_slot,
                                               PSA_ALG_ANY_HASH ) ) != 0 )
        {
            mbedtls_printf( " failed\n  !  "
                            "mbedtls_pk_wrap_as_opaque returned -0x%x\n\n", (unsigned int)  -ret );
            goto exit;
        }
    }
#endif /* MBEDTLS_USE_PSA_CRYPTO */

    mbedtls_printf( " ok (key type: %s)\n", mbedtls_pk_get_name( &pkey ) );
#endif /* MBEDTLS_X509_CRT_PARSE_C */

    /*
     * 2. Setup stuff
     */
    mbedtls_printf( "  . Setting up the SSL/TLS structure..." );
    fflush( stdout );

    if( ( ret = mbedtls_ssl_config_defaults( &conf,
                    MBEDTLS_SSL_IS_CLIENT,
                    opt.transport,
                    MBEDTLS_SSL_PRESET_DEFAULT ) ) != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_ssl_config_defaults returned -0x%x\n\n",
                        (unsigned int) -ret );
        goto exit;
    }

#if defined(MBEDTLS_X509_CRT_PARSE_C)
    /* The default algorithms profile disables SHA-1, but our tests still
       rely on it heavily. */
    if( opt.allow_sha1 > 0 )
    {
        crt_profile_for_test.allowed_mds |= MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA1 );
        mbedtls_ssl_conf_cert_profile( &conf, &crt_profile_for_test );
        mbedtls_ssl_conf_sig_hashes( &conf, ssl_sig_hashes_for_test );
    }

    if( opt.context_crt_cb == 0 )
        mbedtls_ssl_conf_verify( &conf, my_verify, NULL );

    memset( peer_crt_info, 0, sizeof( peer_crt_info ) );
#endif /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
    if( opt.cid_enabled == 1 || opt.cid_enabled_renego == 1 )
    {
        if( opt.cid_enabled == 1        &&
            opt.cid_enabled_renego == 1 &&
            cid_len != cid_renego_len )
        {
            mbedtls_printf( "CID length must not change during renegotiation\n" );
            goto usage;
        }

        if( opt.cid_enabled == 1 )
            ret = mbedtls_ssl_conf_cid( &conf, cid_len,
                                        MBEDTLS_SSL_UNEXPECTED_CID_IGNORE );
        else
            ret = mbedtls_ssl_conf_cid( &conf, cid_renego_len,
                                        MBEDTLS_SSL_UNEXPECTED_CID_IGNORE );

        if( ret != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_cid_len returned -%#04x\n\n",
                            (unsigned int) -ret );
            goto exit;
        }
    }
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */

    if( opt.auth_mode != DFL_AUTH_MODE )
        mbedtls_ssl_conf_authmode( &conf, opt.auth_mode );

#if defined(MBEDTLS_SSL_PROTO_DTLS)
    if( opt.hs_to_min != DFL_HS_TO_MIN || opt.hs_to_max != DFL_HS_TO_MAX )
        mbedtls_ssl_conf_handshake_timeout( &conf, opt.hs_to_min,
                                            opt.hs_to_max );

    if( opt.dgram_packing != DFL_DGRAM_PACKING )
        mbedtls_ssl_set_datagram_packing( &ssl, opt.dgram_packing );
#endif /* MBEDTLS_SSL_PROTO_DTLS */

#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
    if( ( ret = mbedtls_ssl_conf_max_frag_len( &conf, opt.mfl_code ) ) != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_max_frag_len returned %d\n\n",
                        ret );
        goto exit;
    }
#endif

#if defined(MBEDTLS_SSL_DTLS_SRTP)
    const mbedtls_ssl_srtp_profile forced_profile[] =
                                { opt.force_srtp_profile, MBEDTLS_TLS_SRTP_UNSET };
    if( opt.use_srtp == 1 )
    {
        if( opt.force_srtp_profile != 0 )
        {
            ret = mbedtls_ssl_conf_dtls_srtp_protection_profiles ( &conf, forced_profile );
        }
        else
        {
            ret = mbedtls_ssl_conf_dtls_srtp_protection_profiles ( &conf, default_profiles );
        }

        if( ret != 0 )
        {
            mbedtls_printf( " failed\n  ! "
                            "mbedtls_ssl_conf_dtls_srtp_protection_profiles returned %d\n\n",
                            ret );
            goto exit;
        }

    }
    else if( opt.force_srtp_profile != 0 )
    {
        mbedtls_printf( " failed\n  ! must enable use_srtp to force srtp profile\n\n" );
        goto exit;
    }
#endif /* MBEDTLS_SSL_DTLS_SRTP */

#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
    if( opt.extended_ms != DFL_EXTENDED_MS )
        mbedtls_ssl_conf_extended_master_secret( &conf, opt.extended_ms );
#endif

#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
    if( opt.etm != DFL_ETM )
        mbedtls_ssl_conf_encrypt_then_mac( &conf, opt.etm );
#endif

#if defined(MBEDTLS_DHM_C)
    if( opt.dhmlen != DFL_DHMLEN )
        mbedtls_ssl_conf_dhm_min_bitlen( &conf, opt.dhmlen );
#endif

#if defined(MBEDTLS_SSL_ALPN)
    if( opt.alpn_string != NULL )
        if( ( ret = mbedtls_ssl_conf_alpn_protocols( &conf, alpn_list ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_alpn_protocols returned %d\n\n",
                            ret );
            goto exit;
        }
#endif

    if (opt.reproducible)
    {
#if defined(MBEDTLS_HAVE_TIME)
#if defined(MBEDTLS_PLATFORM_TIME_ALT)
        mbedtls_platform_set_time( dummy_constant_time );
#else
        fprintf( stderr, "Warning: reproducible option used without constant time\n" );
#endif
#endif  /* MBEDTLS_HAVE_TIME */
    }
    mbedtls_ssl_conf_rng( &conf, rng_get, &rng );
    mbedtls_ssl_conf_dbg( &conf, my_debug, stdout );

    mbedtls_ssl_conf_read_timeout( &conf, opt.read_timeout );

#if defined(MBEDTLS_SSL_SESSION_TICKETS)
    mbedtls_ssl_conf_session_tickets( &conf, opt.tickets );
#endif

    if( opt.force_ciphersuite[0] != DFL_FORCE_CIPHER )
        mbedtls_ssl_conf_ciphersuites( &conf, opt.force_ciphersuite );

#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
    mbedtls_ssl_conf_tls13_key_exchange_modes( &conf, opt.tls13_kex_modes );
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */

    if( opt.allow_legacy != DFL_ALLOW_LEGACY )
        mbedtls_ssl_conf_legacy_renegotiation( &conf, opt.allow_legacy );
#if defined(MBEDTLS_SSL_RENEGOTIATION)
    mbedtls_ssl_conf_renegotiation( &conf, opt.renegotiation );
#endif

#if defined(MBEDTLS_X509_CRT_PARSE_C)
    if( strcmp( opt.ca_path, "none" ) != 0 &&
        strcmp( opt.ca_file, "none" ) != 0 )
    {
#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
        if( opt.ca_callback != 0 )
            mbedtls_ssl_conf_ca_cb( &conf, ca_callback, &cacert );
        else
#endif
            mbedtls_ssl_conf_ca_chain( &conf, &cacert, NULL );
    }
    if( strcmp( opt.crt_file, "none" ) != 0 &&
        strcmp( opt.key_file, "none" ) != 0 )
    {
        if( ( ret = mbedtls_ssl_conf_own_cert( &conf, &clicert, &pkey ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_own_cert returned %d\n\n",
                            ret );
            goto exit;
        }
    }
#endif  /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_ECP_C)
    if( opt.curves != NULL &&
        strcmp( opt.curves, "default" ) != 0 )
    {
        mbedtls_ssl_conf_groups( &conf, group_list );
    }
#endif

#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
    if( opt.sig_algs != NULL )
        mbedtls_ssl_conf_sig_algs( &conf, sig_alg_list );
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */

#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    if( opt.psk_opaque != 0 )
    {
        key_attributes = psa_key_attributes_init();
        psa_set_key_usage_flags( &key_attributes, PSA_KEY_USAGE_DERIVE );
        psa_set_key_algorithm( &key_attributes, alg );
        psa_set_key_type( &key_attributes, PSA_KEY_TYPE_DERIVE );

        status = psa_import_key( &key_attributes, psk, psk_len, &slot );
        if( status != PSA_SUCCESS )
        {
            ret = MBEDTLS_ERR_SSL_HW_ACCEL_FAILED;
            goto exit;
        }

        if( ( ret = mbedtls_ssl_conf_psk_opaque( &conf, slot,
                                  (const unsigned char *) opt.psk_identity,
                                  strlen( opt.psk_identity ) ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_psk_opaque returned %d\n\n",
                            ret );
            goto exit;
        }
    }
    else
#endif /* MBEDTLS_USE_PSA_CRYPTO */
    if( psk_len > 0 )
    {
        ret = mbedtls_ssl_conf_psk( &conf, psk, psk_len,
                             (const unsigned char *) opt.psk_identity,
                             strlen( opt.psk_identity ) );
        if( ret != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_conf_psk returned %d\n\n", ret );
            goto exit;
        }
    }
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED */

    if( opt.min_version != DFL_MIN_VERSION )
        mbedtls_ssl_conf_min_version( &conf, MBEDTLS_SSL_MAJOR_VERSION_3,
                                      opt.min_version );

    if( opt.max_version != DFL_MAX_VERSION )
        mbedtls_ssl_conf_max_version( &conf, MBEDTLS_SSL_MAJOR_VERSION_3,
                                      opt.max_version );

    if( ( ret = mbedtls_ssl_setup( &ssl, &conf ) ) != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_ssl_setup returned -0x%x\n\n",
                        (unsigned int) -ret );
        goto exit;
    }

    if( opt.eap_tls != 0 )
    {
        mbedtls_ssl_set_export_keys_cb( &ssl, eap_tls_key_derivation,
                                        &eap_tls_keying );
    }
    else if( opt.nss_keylog != 0 )
    {
        mbedtls_ssl_set_export_keys_cb( &ssl,
                                        nss_keylog_export,
                                        NULL );
    }
#if defined( MBEDTLS_SSL_DTLS_SRTP )
    else if( opt.use_srtp != 0 )
    {
        mbedtls_ssl_set_export_keys_cb( &ssl, dtls_srtp_key_derivation,
                                        &dtls_srtp_keying );
    }
#endif /* MBEDTLS_SSL_DTLS_SRTP */

#if defined(MBEDTLS_X509_CRT_PARSE_C)
    if( ( ret = mbedtls_ssl_set_hostname( &ssl, opt.server_name ) ) != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_ssl_set_hostname returned %d\n\n",
                        ret );
        goto exit;
    }
#endif

#if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
    if( opt.ecjpake_pw != DFL_ECJPAKE_PW )
    {
        if( ( ret = mbedtls_ssl_set_hs_ecjpake_password( &ssl,
                        (const unsigned char *) opt.ecjpake_pw,
                                        strlen( opt.ecjpake_pw ) ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_set_hs_ecjpake_password returned %d\n\n",
                            ret );
            goto exit;
        }
    }
#endif

#if defined(MBEDTLS_X509_CRT_PARSE_C)
    if( opt.context_crt_cb == 1 )
        mbedtls_ssl_set_verify( &ssl, my_verify, NULL );
#endif /* MBEDTLS_X509_CRT_PARSE_C */

    io_ctx.ssl = &ssl;
    io_ctx.net = &server_fd;
    mbedtls_ssl_set_bio( &ssl, &io_ctx, send_cb, recv_cb,
                         opt.nbio == 0 ? recv_timeout_cb : NULL );

#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
    if( opt.transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
    {
        if( ( ret = mbedtls_ssl_set_cid( &ssl, opt.cid_enabled,
                                         cid, cid_len ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_set_cid returned %d\n\n",
                            ret );
            goto exit;
        }
    }
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */

#if defined(MBEDTLS_SSL_PROTO_DTLS)
    if( opt.dtls_mtu != DFL_DTLS_MTU )
        mbedtls_ssl_set_mtu( &ssl, opt.dtls_mtu );
#endif

#if defined(MBEDTLS_TIMING_C)
    mbedtls_ssl_set_timer_cb( &ssl, &timer, mbedtls_timing_set_delay,
                                            mbedtls_timing_get_delay );
#endif

#if defined(MBEDTLS_ECP_RESTARTABLE)
    if( opt.ec_max_ops != DFL_EC_MAX_OPS )
        mbedtls_ecp_set_max_ops( opt.ec_max_ops );
#endif

#if defined(MBEDTLS_SSL_DTLS_SRTP)
    if( opt.use_srtp != 0 && strlen( opt.mki ) != 0 )
    {
        if( mbedtls_test_unhexify( mki, sizeof( mki ),
                                   opt.mki,&mki_len ) != 0 )
        {
            mbedtls_printf( "mki value not valid hex\n" );
            goto exit;
        }

        mbedtls_ssl_conf_srtp_mki_value_supported( &conf, MBEDTLS_SSL_DTLS_SRTP_MKI_SUPPORTED );
        if( ( ret = mbedtls_ssl_dtls_srtp_set_mki_value( &ssl, mki,
                                                         (uint16_t) strlen( opt.mki ) / 2 ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_dtls_srtp_set_mki_value returned %d\n\n", ret );
            goto exit;
        }
    }
#endif

    mbedtls_printf( " ok\n" );

    /*
     * 3. Start the connection
     */
    if( opt.server_addr == NULL)
        opt.server_addr = opt.server_name;

    mbedtls_printf( "  . Connecting to %s/%s/%s...",
            opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM ? "tcp" : "udp",
            opt.server_addr, opt.server_port );
    fflush( stdout );

    if( ( ret = mbedtls_net_connect( &server_fd,
                       opt.server_addr, opt.server_port,
                       opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM ?
                       MBEDTLS_NET_PROTO_TCP : MBEDTLS_NET_PROTO_UDP ) ) != 0 )
    {
        mbedtls_printf( " failed\n  ! mbedtls_net_connect returned -0x%x\n\n",
                        (unsigned int) -ret );
        goto exit;
    }

    if( opt.nbio > 0 )
        ret = mbedtls_net_set_nonblock( &server_fd );
    else
        ret = mbedtls_net_set_block( &server_fd );
    if( ret != 0 )
    {
        mbedtls_printf( " failed\n  ! net_set_(non)block() returned -0x%x\n\n",
                        (unsigned int) -ret );
        goto exit;
    }

    mbedtls_printf( " ok\n" );

    /*
     * 4. Handshake
     */
    mbedtls_printf( "  . Performing the SSL/TLS handshake..." );
    fflush( stdout );

    while( ( ret = mbedtls_ssl_handshake( &ssl ) ) != 0 )
    {
        if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
            ret != MBEDTLS_ERR_SSL_WANT_WRITE &&
            ret != MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_handshake returned -0x%x\n",
                            (unsigned int) -ret );
            if( ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED )
                mbedtls_printf(
                    "    Unable to verify the server's certificate. "
                        "Either it is invalid,\n"
                    "    or you didn't set ca_file or ca_path "
                        "to an appropriate value.\n"
                    "    Alternatively, you may want to use "
                        "auth_mode=optional for testing purposes.\n" );
            mbedtls_printf( "\n" );
            goto exit;
        }

#if defined(MBEDTLS_ECP_RESTARTABLE)
        if( ret == MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
            continue;
#endif

        /* For event-driven IO, wait for socket to become available */
        if( opt.event == 1 /* level triggered IO */ )
        {
#if defined(MBEDTLS_TIMING_C)
            ret = idle( &server_fd, &timer, ret );
#else
            ret = idle( &server_fd, ret );
#endif
            if( ret != 0 )
                goto exit;
        }
    }

    mbedtls_printf( " ok\n    [ Protocol is %s ]\n    [ Ciphersuite is %s ]\n",
                    mbedtls_ssl_get_version( &ssl ),
                    mbedtls_ssl_get_ciphersuite( &ssl ) );

    if( ( ret = mbedtls_ssl_get_record_expansion( &ssl ) ) >= 0 )
        mbedtls_printf( "    [ Record expansion is %d ]\n", ret );
    else
        mbedtls_printf( "    [ Record expansion is unknown ]\n" );

#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
    mbedtls_printf( "    [ Maximum incoming record payload length is %u ]\n",
                    (unsigned int) mbedtls_ssl_get_max_in_record_payload( &ssl ) );
    mbedtls_printf( "    [ Maximum outgoing record payload length is %u ]\n",
                    (unsigned int) mbedtls_ssl_get_max_out_record_payload( &ssl ) );
#endif

#if defined(MBEDTLS_SSL_ALPN)
    if( opt.alpn_string != NULL )
    {
        const char *alp = mbedtls_ssl_get_alpn_protocol( &ssl );
        mbedtls_printf( "    [ Application Layer Protocol is %s ]\n",
                alp ? alp : "(none)" );
    }
#endif

    if( opt.eap_tls != 0  )
    {
        size_t j = 0;

        if( ( ret = mbedtls_ssl_tls_prf( eap_tls_keying.tls_prf_type,
                                         eap_tls_keying.master_secret,
                                         sizeof( eap_tls_keying.master_secret ),
                                         eap_tls_label,
                                         eap_tls_keying.randbytes,
                                         sizeof( eap_tls_keying.randbytes ),
                                         eap_tls_keymaterial,
                                         sizeof( eap_tls_keymaterial ) ) )
                                         != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_tls_prf returned -0x%x\n\n",
                            (unsigned int) -ret );
            goto exit;
        }

        mbedtls_printf( "    EAP-TLS key material is:" );
        for( j = 0; j < sizeof( eap_tls_keymaterial ); j++ )
        {
            if( j % 8 == 0 )
                mbedtls_printf("\n    ");
            mbedtls_printf("%02x ", eap_tls_keymaterial[j] );
        }
        mbedtls_printf("\n");

        if( ( ret = mbedtls_ssl_tls_prf( eap_tls_keying.tls_prf_type, NULL, 0,
                                         eap_tls_label,
                                         eap_tls_keying.randbytes,
                                         sizeof( eap_tls_keying.randbytes ),
                                         eap_tls_iv,
                                         sizeof( eap_tls_iv ) ) ) != 0 )
         {
             mbedtls_printf( " failed\n  ! mbedtls_ssl_tls_prf returned -0x%x\n\n",
                             (unsigned int) -ret );
             goto exit;
         }

        mbedtls_printf( "    EAP-TLS IV is:" );
        for( j = 0; j < sizeof( eap_tls_iv ); j++ )
        {
            if( j % 8 == 0 )
                mbedtls_printf("\n    ");
            mbedtls_printf("%02x ", eap_tls_iv[j] );
        }
        mbedtls_printf("\n");
    }

#if defined( MBEDTLS_SSL_DTLS_SRTP )
    else if( opt.use_srtp != 0  )
    {
        size_t j = 0;
        mbedtls_dtls_srtp_info dtls_srtp_negotiation_result;
        mbedtls_ssl_get_dtls_srtp_negotiation_result( &ssl, &dtls_srtp_negotiation_result );

        if( dtls_srtp_negotiation_result.chosen_dtls_srtp_profile
                                == MBEDTLS_TLS_SRTP_UNSET )
        {
            mbedtls_printf( "    Unable to negotiate "
                            "the use of DTLS-SRTP\n" );
        }
        else
        {
            if( ( ret = mbedtls_ssl_tls_prf( dtls_srtp_keying.tls_prf_type,
                                             dtls_srtp_keying.master_secret,
                                             sizeof( dtls_srtp_keying.master_secret ),
                                             dtls_srtp_label,
                                             dtls_srtp_keying.randbytes,
                                             sizeof( dtls_srtp_keying.randbytes ),
                                             dtls_srtp_key_material,
                                             sizeof( dtls_srtp_key_material ) ) )
                                             != 0 )
            {
                mbedtls_printf( " failed\n  ! mbedtls_ssl_tls_prf returned -0x%x\n\n",
                                (unsigned int) -ret );
                goto exit;
            }

            mbedtls_printf( "    DTLS-SRTP key material is:" );
            for( j = 0; j < sizeof( dtls_srtp_key_material ); j++ )
            {
                if( j % 8 == 0 )
                    mbedtls_printf( "\n    " );
                mbedtls_printf( "%02x ", dtls_srtp_key_material[j] );
            }
            mbedtls_printf( "\n" );

            /* produce a less readable output used to perform automatic checks
             * - compare client and server output
             * - interop test with openssl which client produces this kind of output
             */
            mbedtls_printf( "    Keying material: " );
            for( j = 0; j < sizeof( dtls_srtp_key_material ); j++ )
            {
                mbedtls_printf( "%02X", dtls_srtp_key_material[j] );
            }
            mbedtls_printf( "\n" );

            if ( dtls_srtp_negotiation_result.mki_len > 0 )
            {
                mbedtls_printf( "    DTLS-SRTP mki value: " );
                for( j = 0; j < dtls_srtp_negotiation_result.mki_len; j++ )
                {
                    mbedtls_printf( "%02X", dtls_srtp_negotiation_result.mki_value[j] );
                }
            }
            else
            {
                mbedtls_printf( "    DTLS-SRTP no mki value negotiated" );
            }
            mbedtls_printf( "\n" );
        }
    }
#endif /* MBEDTLS_SSL_DTLS_SRTP */
    if( opt.reconnect != 0 )
    {
        mbedtls_printf("  . Saving session for reuse..." );
        fflush( stdout );

        if( opt.reco_mode == 1 )
        {
            mbedtls_ssl_session exported_session;

            /* free any previously saved data */
            if( session_data != NULL )
            {
                mbedtls_platform_zeroize( session_data, session_data_len );
                mbedtls_free( session_data );
                session_data = NULL;
            }

            mbedtls_ssl_session_init( &exported_session );
            ret = mbedtls_ssl_get_session( &ssl, &exported_session );
            if( ret != 0 )
            {
                mbedtls_printf(
                    "failed\n  ! mbedtls_ssl_get_session() returned -%#02x\n",
                    (unsigned) -ret );
                goto exit;
            }

            /* get size of the buffer needed */
            mbedtls_ssl_session_save( &exported_session, NULL, 0, &session_data_len );
            session_data = mbedtls_calloc( 1, session_data_len );
            if( session_data == NULL )
            {
                mbedtls_printf( " failed\n  ! alloc %u bytes for session data\n",
                                (unsigned) session_data_len );
                mbedtls_ssl_session_free( &exported_session );
                ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
                goto exit;
            }

            /* actually save session data */
            if( ( ret = mbedtls_ssl_session_save( &exported_session,
                                                  session_data, session_data_len,
                                                  &session_data_len ) ) != 0 )
            {
                mbedtls_printf( " failed\n  ! mbedtls_ssl_session_saved returned -0x%04x\n\n",
                                (unsigned int) -ret );
                mbedtls_ssl_session_free( &exported_session );
                goto exit;
            }

            mbedtls_ssl_session_free( &exported_session );
        }
        else
        {
            if( ( ret = mbedtls_ssl_get_session( &ssl, &saved_session ) ) != 0 )
            {
                mbedtls_printf( " failed\n  ! mbedtls_ssl_get_session returned -0x%x\n\n",
                                (unsigned int) -ret );
                goto exit;
            }
        }

        mbedtls_printf( " ok\n" );

        if( opt.reco_mode == 1 )
        {
            mbedtls_printf( "    [ Saved %u bytes of session data]\n",
                            (unsigned) session_data_len );
        }
    }

#if defined(MBEDTLS_X509_CRT_PARSE_C)
    /*
     * 5. Verify the server certificate
     */
    mbedtls_printf( "  . Verifying peer X.509 certificate..." );

    if( ( flags = mbedtls_ssl_get_verify_result( &ssl ) ) != 0 )
    {
        char vrfy_buf[512];
        mbedtls_printf( " failed\n" );

        x509_crt_verify_info( vrfy_buf, sizeof( vrfy_buf ),
                                      "  ! ", flags );

        mbedtls_printf( "%s\n", vrfy_buf );
    }
    else
        mbedtls_printf( " ok\n" );

#if !defined(MBEDTLS_X509_REMOVE_INFO)
    mbedtls_printf( "  . Peer certificate information    ...\n" );
    mbedtls_printf( "%s\n", peer_crt_info );
#endif /* !MBEDTLS_X509_REMOVE_INFO */
#endif /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
    ret = report_cid_usage( &ssl, "initial handshake" );
    if( ret != 0 )
        goto exit;

    if( opt.transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
    {
        if( ( ret = mbedtls_ssl_set_cid( &ssl, opt.cid_enabled_renego,
                                         cid_renego,
                                         cid_renego_len ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_set_cid returned %d\n\n",
                            ret );
            goto exit;
        }
    }
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */

#if defined(MBEDTLS_SSL_RENEGOTIATION)
    if( opt.renegotiate )
    {
        /*
         * Perform renegotiation (this must be done when the server is waiting
         * for input from our side).
         */
        mbedtls_printf( "  . Performing renegotiation..." );
        fflush( stdout );
        while( ( ret = mbedtls_ssl_renegotiate( &ssl ) ) != 0 )
        {
            if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
                ret != MBEDTLS_ERR_SSL_WANT_WRITE &&
                ret != MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
            {
                mbedtls_printf( " failed\n  ! mbedtls_ssl_renegotiate returned %d\n\n",
                                ret );
                goto exit;
            }

#if defined(MBEDTLS_ECP_RESTARTABLE)
            if( ret == MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
                continue;
#endif

            /* For event-driven IO, wait for socket to become available */
            if( opt.event == 1 /* level triggered IO */ )
            {
#if defined(MBEDTLS_TIMING_C)
                idle( &server_fd, &timer, ret );
#else
                idle( &server_fd, ret );
#endif
            }

        }
        mbedtls_printf( " ok\n" );
    }
#endif /* MBEDTLS_SSL_RENEGOTIATION */

#if defined(MBEDTLS_SSL_DTLS_CONNECTION_ID)
    ret = report_cid_usage( &ssl, "after renegotiation" );
    if( ret != 0 )
        goto exit;
#endif /* MBEDTLS_SSL_DTLS_CONNECTION_ID */

    /*
     * 6. Write the GET request
     */
    retry_left = opt.max_resend;
send_request:
    mbedtls_printf( "  > Write to server:" );
    fflush( stdout );

    len = mbedtls_snprintf( (char *) buf, sizeof( buf ) - 1, GET_REQUEST,
                            opt.request_page );
    tail_len = (int) strlen( GET_REQUEST_END );

    /* Add padding to GET request to reach opt.request_size in length */
    if( opt.request_size != DFL_REQUEST_SIZE &&
        len + tail_len < opt.request_size )
    {
        memset( buf + len, 'A', opt.request_size - len - tail_len );
        len += opt.request_size - len - tail_len;
    }

    strncpy( (char *) buf + len, GET_REQUEST_END, sizeof( buf ) - len - 1 );
    len += tail_len;

    /* Truncate if request size is smaller than the "natural" size */
    if( opt.request_size != DFL_REQUEST_SIZE &&
        len > opt.request_size )
    {
        len = opt.request_size;

        /* Still end with \r\n unless that's really not possible */
        if( len >= 2 ) buf[len - 2] = '\r';
        if( len >= 1 ) buf[len - 1] = '\n';
    }

    if( opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM )
    {
        written = 0;
        frags = 0;

        do
        {
            while( ( ret = mbedtls_ssl_write( &ssl, buf + written,
                                              len - written ) ) < 0 )
            {
                if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
                    ret != MBEDTLS_ERR_SSL_WANT_WRITE &&
                    ret != MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
                {
                    mbedtls_printf( " failed\n  ! mbedtls_ssl_write returned -0x%x\n\n",
                                    (unsigned int) -ret );
                    goto exit;
                }

                /* For event-driven IO, wait for socket to become available */
                if( opt.event == 1 /* level triggered IO */ )
                {
#if defined(MBEDTLS_TIMING_C)
                    idle( &server_fd, &timer, ret );
#else
                    idle( &server_fd, ret );
#endif
                }
            }

            frags++;
            written += ret;
        }
        while( written < len );
    }
    else /* Not stream, so datagram */
    {
        while( 1 )
        {
            ret = mbedtls_ssl_write( &ssl, buf, len );

#if defined(MBEDTLS_ECP_RESTARTABLE)
            if( ret == MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
                continue;
#endif

            if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
                ret != MBEDTLS_ERR_SSL_WANT_WRITE )
                break;

            /* For event-driven IO, wait for socket to become available */
            if( opt.event == 1 /* level triggered IO */ )
            {
#if defined(MBEDTLS_TIMING_C)
                idle( &server_fd, &timer, ret );
#else
                idle( &server_fd, ret );
#endif
            }
        }

        if( ret < 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_write returned %d\n\n",
                            ret );
            goto exit;
        }

        frags = 1;
        written = ret;

        if( written < len )
        {
            mbedtls_printf( " warning\n  ! request didn't fit into single datagram and "
                            "was truncated to size %u", (unsigned) written );
        }
    }

    buf[written] = '\0';
    mbedtls_printf( " %d bytes written in %d fragments\n\n%s\n",
                    written, frags, (char *) buf );

    /* Send a non-empty request if request_size == 0 */
    if ( len == 0 )
    {
        opt.request_size = DFL_REQUEST_SIZE;
        goto send_request;
    }

    /*
     * 7. Read the HTTP response
     */
    mbedtls_printf( "  < Read from server:" );
    fflush( stdout );

    /*
     * TLS and DTLS need different reading styles (stream vs datagram)
     */
    if( opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM )
    {
        do
        {
            len = sizeof( buf ) - 1;
            memset( buf, 0, sizeof( buf ) );
            ret = mbedtls_ssl_read( &ssl, buf, len );

#if defined(MBEDTLS_ECP_RESTARTABLE)
            if( ret == MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
                continue;
#endif

            if( ret == MBEDTLS_ERR_SSL_WANT_READ ||
                ret == MBEDTLS_ERR_SSL_WANT_WRITE )
            {
                /* For event-driven IO, wait for socket to become available */
                if( opt.event == 1 /* level triggered IO */ )
                {
#if defined(MBEDTLS_TIMING_C)
                    idle( &server_fd, &timer, ret );
#else
                    idle( &server_fd, ret );
#endif
                }
                continue;
            }

            if( ret <= 0 )
            {
                switch( ret )
                {
                    case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
                        mbedtls_printf( " connection was closed gracefully\n" );
                        ret = 0;
                        goto close_notify;

                    case 0:
                    case MBEDTLS_ERR_NET_CONN_RESET:
                        mbedtls_printf( " connection was reset by peer\n" );
                        ret = 0;
                        goto reconnect;

                    default:
                        mbedtls_printf( " mbedtls_ssl_read returned -0x%x\n",
                                        (unsigned int) -ret );
                        goto exit;
                }
            }

            len = ret;
            buf[len] = '\0';
            mbedtls_printf( " %d bytes read\n\n%s", len, (char *) buf );

            /* End of message should be detected according to the syntax of the
             * application protocol (eg HTTP), just use a dummy test here. */
            if( ret > 0 && buf[len-1] == '\n' )
            {
                ret = 0;
                break;
            }
        }
        while( 1 );
    }
    else /* Not stream, so datagram */
    {
        len = sizeof( buf ) - 1;
        memset( buf, 0, sizeof( buf ) );

        while( 1 )
        {
            ret = mbedtls_ssl_read( &ssl, buf, len );

#if defined(MBEDTLS_ECP_RESTARTABLE)
            if( ret == MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
                continue;
#endif

            if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
                ret != MBEDTLS_ERR_SSL_WANT_WRITE )
                break;

            /* For event-driven IO, wait for socket to become available */
            if( opt.event == 1 /* level triggered IO */ )
            {
#if defined(MBEDTLS_TIMING_C)
                idle( &server_fd, &timer, ret );
#else
                idle( &server_fd, ret );
#endif
            }
        }

        if( ret <= 0 )
        {
            switch( ret )
            {
                case MBEDTLS_ERR_SSL_TIMEOUT:
                    mbedtls_printf( " timeout\n" );
                    if( retry_left-- > 0 )
                        goto send_request;
                    goto exit;

                case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
                    mbedtls_printf( " connection was closed gracefully\n" );
                    ret = 0;
                    goto close_notify;

                default:
                    mbedtls_printf( " mbedtls_ssl_read returned -0x%x\n", (unsigned int) -ret );
                    goto exit;
            }
        }

        len = ret;
        buf[len] = '\0';
        mbedtls_printf( " %d bytes read\n\n%s", len, (char *) buf );
        ret = 0;
    }

    /*
     * 7b. Simulate hard reset and reconnect from same port?
     */
    if( opt.reconnect_hard != 0 )
    {
        opt.reconnect_hard = 0;

        mbedtls_printf( "  . Restarting connection from same port..." );
        fflush( stdout );

#if defined(MBEDTLS_X509_CRT_PARSE_C)
        memset( peer_crt_info, 0, sizeof( peer_crt_info ) );
#endif /* MBEDTLS_X509_CRT_PARSE_C */

        if( ( ret = mbedtls_ssl_session_reset( &ssl ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_session_reset returned -0x%x\n\n",
                            (unsigned int) -ret );
            goto exit;
        }

        while( ( ret = mbedtls_ssl_handshake( &ssl ) ) != 0 )
        {
            if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
                ret != MBEDTLS_ERR_SSL_WANT_WRITE &&
                ret != MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
            {
                mbedtls_printf( " failed\n  ! mbedtls_ssl_handshake returned -0x%x\n\n",
                                (unsigned int) -ret );
                goto exit;
            }

            /* For event-driven IO, wait for socket to become available */
            if( opt.event == 1 /* level triggered IO */ )
            {
#if defined(MBEDTLS_TIMING_C)
                idle( &server_fd, &timer, ret );
#else
                idle( &server_fd, ret );
#endif
            }
        }

        mbedtls_printf( " ok\n" );

        goto send_request;
    }

    /*
     * 7c. Simulate serialize/deserialize and go back to data exchange
     */
#if defined(MBEDTLS_SSL_CONTEXT_SERIALIZATION)
    if( opt.serialize != 0 )
    {
        size_t buf_len;

        mbedtls_printf( "  . Serializing live connection..." );

        ret = mbedtls_ssl_context_save( &ssl, NULL, 0, &buf_len );
        if( ret != MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_context_save returned "
                            "-0x%x\n\n", (unsigned int) -ret );

            goto exit;
        }

        if( ( context_buf = mbedtls_calloc( 1, buf_len ) ) == NULL )
        {
            mbedtls_printf( " failed\n  ! Couldn't allocate buffer for "
                            "serialized context" );

            goto exit;
        }
        context_buf_len = buf_len;

        if( ( ret = mbedtls_ssl_context_save( &ssl, context_buf,
                                              buf_len, &buf_len ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_context_save returned "
                            "-0x%x\n\n", (unsigned int) -ret );

            goto exit;
        }

        mbedtls_printf( " ok\n" );

        /* Save serialized context to the 'opt.context_file' as a base64 code */
        if( 0 < strlen( opt.context_file ) )
        {
            FILE *b64_file;
            uint8_t *b64_buf;
            size_t b64_len;

            mbedtls_printf( "  . Save serialized context to a file... " );

            mbedtls_base64_encode( NULL, 0, &b64_len, context_buf, buf_len );

            if( ( b64_buf = mbedtls_calloc( 1, b64_len ) ) == NULL )
            {
                mbedtls_printf( "failed\n  ! Couldn't allocate buffer for "
                                "the base64 code\n" );
                goto exit;
            }

            if( ( ret = mbedtls_base64_encode( b64_buf, b64_len, &b64_len,
                                               context_buf, buf_len ) ) != 0 )
            {
                mbedtls_printf( "failed\n  ! mbedtls_base64_encode returned "
                            "-0x%x\n", (unsigned int) -ret );
                mbedtls_free( b64_buf );
                goto exit;
            }

            if( ( b64_file = fopen( opt.context_file, "w" ) ) == NULL )
            {
                mbedtls_printf( "failed\n  ! Cannot open '%s' for writing.\n",
                                opt.context_file );
                mbedtls_free( b64_buf );
                goto exit;
            }

            if( b64_len != fwrite( b64_buf, 1, b64_len, b64_file ) )
            {
                mbedtls_printf( "failed\n  ! fwrite(%ld bytes) failed\n",
                                (long) b64_len );
                mbedtls_free( b64_buf );
                fclose( b64_file );
                goto exit;
            }

            mbedtls_free( b64_buf );
            fclose( b64_file );

            mbedtls_printf( "ok\n" );
        }

        if( opt.serialize == 1 )
        {
            /* nothing to do here, done by context_save() already */
            mbedtls_printf( "  . Context has been reset... ok\n" );
        }

        if( opt.serialize == 2 )
        {
            mbedtls_printf( "  . Freeing and reinitializing context..." );

            mbedtls_ssl_free( &ssl );

            mbedtls_ssl_init( &ssl );

            if( ( ret = mbedtls_ssl_setup( &ssl, &conf ) ) != 0 )
            {
                mbedtls_printf( " failed\n  ! mbedtls_ssl_setup returned "
                                "-0x%x\n\n", (unsigned int) -ret );
                goto exit;
            }

            if( opt.nbio == 2 )
                mbedtls_ssl_set_bio( &ssl, &server_fd, delayed_send,
                                     delayed_recv, NULL );
            else
                mbedtls_ssl_set_bio( &ssl, &server_fd, mbedtls_net_send,
                            mbedtls_net_recv,
                            opt.nbio == 0 ? mbedtls_net_recv_timeout : NULL );

#if defined(MBEDTLS_TIMING_C)
                mbedtls_ssl_set_timer_cb( &ssl, &timer,
                                          mbedtls_timing_set_delay,
                                          mbedtls_timing_get_delay );
#endif /* MBEDTLS_TIMING_C */

            mbedtls_printf( " ok\n" );
        }

        mbedtls_printf( "  . Deserializing connection..." );

        if( ( ret = mbedtls_ssl_context_load( &ssl, context_buf,
                                              buf_len ) ) != 0 )
        {
            mbedtls_printf( "failed\n  ! mbedtls_ssl_context_load returned "
                            "-0x%x\n\n", (unsigned int) -ret );

            goto exit;
        }

        mbedtls_free( context_buf );
        context_buf = NULL;
        context_buf_len = 0;

        mbedtls_printf( " ok\n" );
    }
#endif /* MBEDTLS_SSL_CONTEXT_SERIALIZATION */

    /*
     * 7d. Continue doing data exchanges?
     */
    if( --opt.exchanges > 0 )
        goto send_request;

    /*
     * 8. Done, cleanly close the connection
     */
close_notify:
    mbedtls_printf( "  . Closing the connection..." );
    fflush( stdout );

    /*
     * Most of the time sending a close_notify before closing is the right
     * thing to do. However, when the server already knows how many messages
     * are expected and closes the connection by itself, this alert becomes
     * redundant. Sometimes with DTLS this redundancy becomes a problem by
     * leading to a race condition where the server might close the connection
     * before seeing the alert, and since UDP is connection-less when the
     * alert arrives it will be seen as a new connection, which will fail as
     * the alert is clearly not a valid ClientHello. This may cause spurious
     * failures in tests that use DTLS and resumption with ssl_server2 in
     * ssl-opt.sh, avoided by enabling skip_close_notify client-side.
     */
    if( opt.skip_close_notify == 0 )
    {
        /* No error checking, the connection might be closed already */
        do ret = mbedtls_ssl_close_notify( &ssl );
        while( ret == MBEDTLS_ERR_SSL_WANT_WRITE );
        ret = 0;
    }

    mbedtls_printf( " done\n" );

    /*
     * 9. Reconnect?
     */
reconnect:
    if( opt.reconnect != 0 )
    {
        --opt.reconnect;

        mbedtls_net_free( &server_fd );

#if defined(MBEDTLS_TIMING_C)
        if( opt.reco_delay > 0 )
            mbedtls_net_usleep( 1000000 * opt.reco_delay );
#endif

        mbedtls_printf( "  . Reconnecting with saved session..." );

#if defined(MBEDTLS_X509_CRT_PARSE_C)
        memset( peer_crt_info, 0, sizeof( peer_crt_info ) );
#endif /* MBEDTLS_X509_CRT_PARSE_C */

        if( ( ret = mbedtls_ssl_session_reset( &ssl ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_session_reset returned -0x%x\n\n",
                            (unsigned int) -ret );
            goto exit;
        }

        if( opt.reco_mode == 1 )
        {
            if( ( ret = mbedtls_ssl_session_load( &saved_session,
                                                  session_data,
                                                  session_data_len ) ) != 0 )
            {
                mbedtls_printf( " failed\n  ! mbedtls_ssl_session_load returned -0x%x\n\n",
                                (unsigned int) -ret );
                goto exit;
            }
        }

        if( ( ret = mbedtls_ssl_set_session( &ssl, &saved_session ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_ssl_set_session returned -0x%x\n\n",
                            (unsigned int) -ret );
            goto exit;
        }

        if( ( ret = mbedtls_net_connect( &server_fd,
                        opt.server_addr, opt.server_port,
                        opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM ?
                        MBEDTLS_NET_PROTO_TCP : MBEDTLS_NET_PROTO_UDP ) ) != 0 )
        {
            mbedtls_printf( " failed\n  ! mbedtls_net_connect returned -0x%x\n\n",
                            (unsigned int) -ret );
            goto exit;
        }

        if( opt.nbio > 0 )
            ret = mbedtls_net_set_nonblock( &server_fd );
        else
            ret = mbedtls_net_set_block( &server_fd );
        if( ret != 0 )
        {
            mbedtls_printf( " failed\n  ! net_set_(non)block() returned -0x%x\n\n",
                            (unsigned int) -ret );
            goto exit;
        }

        while( ( ret = mbedtls_ssl_handshake( &ssl ) ) != 0 )
        {
            if( ret != MBEDTLS_ERR_SSL_WANT_READ &&
                ret != MBEDTLS_ERR_SSL_WANT_WRITE &&
                ret != MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS )
            {
                mbedtls_printf( " failed\n  ! mbedtls_ssl_handshake returned -0x%x\n\n",
                                (unsigned int) -ret );
                goto exit;
            }
        }

        mbedtls_printf( " ok\n" );

        goto send_request;
    }

    /*
     * Cleanup and exit
     */
exit:
#ifdef MBEDTLS_ERROR_C
    if( ret != 0 )
    {
        char error_buf[100];
        mbedtls_strerror( ret, error_buf, 100 );
        mbedtls_printf("Last error was: -0x%X - %s\n\n", (unsigned int) -ret, error_buf );
    }
#endif

    mbedtls_net_free( &server_fd );

    mbedtls_ssl_free( &ssl );
    mbedtls_ssl_config_free( &conf );
    mbedtls_ssl_session_free( &saved_session );

    if( session_data != NULL )
        mbedtls_platform_zeroize( session_data, session_data_len );
    mbedtls_free( session_data );
#if defined(MBEDTLS_SSL_CONTEXT_SERIALIZATION)
    if( context_buf != NULL )
        mbedtls_platform_zeroize( context_buf, context_buf_len );
    mbedtls_free( context_buf );
#endif

#if defined(MBEDTLS_X509_CRT_PARSE_C)
    mbedtls_x509_crt_free( &clicert );
    mbedtls_x509_crt_free( &cacert );
    mbedtls_pk_free( &pkey );
#if defined(MBEDTLS_USE_PSA_CRYPTO)
    psa_destroy_key( key_slot );
#endif
#endif /* MBEDTLS_X509_CRT_PARSE_C */

#if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED) && \
    defined(MBEDTLS_USE_PSA_CRYPTO)
    if( opt.psk_opaque != 0 )
    {
        /* This is ok even if the slot hasn't been
         * initialized (we might have jumed here
         * immediately because of bad cmd line params,
         * for example). */
        status = psa_destroy_key( slot );
        if( ( status != PSA_SUCCESS ) &&
            ( opt.query_config_mode == DFL_QUERY_CONFIG_MODE ) )
        {
            mbedtls_printf( "Failed to destroy key slot %u - error was %d",
                            (unsigned) slot, (int) status );
            if( ret == 0 )
                ret = MBEDTLS_ERR_SSL_HW_ACCEL_FAILED;
        }
    }
#endif /* MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED &&
          MBEDTLS_USE_PSA_CRYPTO */

#if defined(MBEDTLS_USE_PSA_CRYPTO)
    const char* message = mbedtls_test_helper_is_psa_leaking();
    if( message )
    {
        if( ret == 0 )
            ret = 1;
        mbedtls_printf( "PSA memory leak detected: %s\n",  message);
    }
#endif /* MBEDTLS_USE_PSA_CRYPTO */

    /* For builds with MBEDTLS_TEST_USE_PSA_CRYPTO_RNG psa crypto
     * resources are freed by rng_free(). */
#if defined(MBEDTLS_USE_PSA_CRYPTO) && \
    !defined(MBEDTLS_TEST_USE_PSA_CRYPTO_RNG)
    mbedtls_psa_crypto_free( );
#endif

    rng_free( &rng );

#if defined(MBEDTLS_TEST_HOOKS)
    if( test_hooks_failure_detected( ) )
    {
        if( ret == 0 )
            ret = 1;
        mbedtls_printf( "Test hooks detected errors.\n" );
    }
    test_hooks_free( );
#endif /* MBEDTLS_TEST_HOOKS */

#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
#if defined(MBEDTLS_MEMORY_DEBUG)
    mbedtls_memory_buffer_alloc_status();
#endif
    mbedtls_memory_buffer_alloc_free();
#endif  /* MBEDTLS_MEMORY_BUFFER_ALLOC_C */

#if defined(_WIN32)
    if( opt.query_config_mode == DFL_QUERY_CONFIG_MODE )
    {
        mbedtls_printf( "  + Press Enter to exit this program.\n" );
        fflush( stdout ); getchar();
    }
#endif

    // Shell can not handle large exit numbers -> 1 for errors
    if( ret < 0 )
        ret = 1;

    if( opt.query_config_mode == DFL_QUERY_CONFIG_MODE )
        mbedtls_exit( ret );
    else
        mbedtls_exit( query_config_ret );
}
#endif /* !MBEDTLS_SSL_TEST_IMPOSSIBLE && MBEDTLS_SSL_CLI_C */