/* $Id: transport_srtp.c 4366 2013-02-21 20:41:31Z ming $ */ /* * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) * Copyright (C) 2003-2008 Benny Prijono * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include #include #include #include #if defined(PJMEDIA_HAS_SRTP) && (PJMEDIA_HAS_SRTP != 0) #include #define THIS_FILE "transport_srtp.c" /* Maximum size of outgoing packet */ #define MAX_RTP_BUFFER_LEN PJMEDIA_MAX_MTU #define MAX_RTCP_BUFFER_LEN PJMEDIA_MAX_MTU /* Maximum SRTP crypto key length */ #define MAX_KEY_LEN 128 /* Initial value of probation counter. When probation counter > 0, * it means SRTP is in probation state, and it may restart when * srtp_unprotect() returns err_status_replay_* */ #define PROBATION_CNT_INIT 100 #define DEACTIVATE_MEDIA(pool, m) pjmedia_sdp_media_deactivate(pool, m) static const pj_str_t ID_RTP_AVP = { "RTP/AVP", 7 }; static const pj_str_t ID_RTP_SAVP = { "RTP/SAVP", 8 }; static const pj_str_t ID_INACTIVE = { "inactive", 8 }; static const pj_str_t ID_CRYPTO = { "crypto", 6 }; typedef struct crypto_suite { char *name; cipher_type_id_t cipher_type; unsigned cipher_key_len; auth_type_id_t auth_type; unsigned auth_key_len; unsigned srtp_auth_tag_len; unsigned srtcp_auth_tag_len; sec_serv_t service; } crypto_suite; /* Crypto suites as defined on RFC 4568 */ static crypto_suite crypto_suites[] = { /* plain RTP/RTCP (no cipher & no auth) */ {"NULL", NULL_CIPHER, 0, NULL_AUTH, 0, 0, 0, sec_serv_none}, /* cipher AES_CM, auth HMAC_SHA1, auth tag len = 10 octets */ {"AES_CM_128_HMAC_SHA1_80", AES_128_ICM, 30, HMAC_SHA1, 20, 10, 10, sec_serv_conf_and_auth}, /* cipher AES_CM, auth HMAC_SHA1, auth tag len = 4 octets */ {"AES_CM_128_HMAC_SHA1_32", AES_128_ICM, 30, HMAC_SHA1, 20, 4, 10, sec_serv_conf_and_auth}, /* * F8_128_HMAC_SHA1_8 not supported by libsrtp? * {"F8_128_HMAC_SHA1_8", NULL_CIPHER, 0, NULL_AUTH, 0, 0, 0, sec_serv_none} */ }; typedef struct transport_srtp { pjmedia_transport base; /**< Base transport interface. */ pj_pool_t *pool; /**< Pool for transport SRTP. */ pj_lock_t *mutex; /**< Mutex for libsrtp contexts.*/ char rtp_tx_buffer[MAX_RTP_BUFFER_LEN]; char rtcp_tx_buffer[MAX_RTCP_BUFFER_LEN]; pjmedia_srtp_setting setting; unsigned media_option; /* SRTP policy */ pj_bool_t session_inited; pj_bool_t offerer_side; pj_bool_t bypass_srtp; char tx_key[MAX_KEY_LEN]; char rx_key[MAX_KEY_LEN]; pjmedia_srtp_crypto tx_policy; pjmedia_srtp_crypto rx_policy; /* Temporary policy for negotiation */ pjmedia_srtp_crypto tx_policy_neg; pjmedia_srtp_crypto rx_policy_neg; /* libSRTP contexts */ srtp_t srtp_tx_ctx; srtp_t srtp_rx_ctx; /* Stream information */ void *user_data; void (*rtp_cb)( void *user_data, void *pkt, pj_ssize_t size); void (*rtcp_cb)(void *user_data, void *pkt, pj_ssize_t size); /* Transport information */ pjmedia_transport *member_tp; /**< Underlying transport. */ /* SRTP usage policy of peer. This field is updated when media is starting. * This is useful when SRTP is in optional mode and peer is using mandatory * mode, so when local is about to reinvite/update, it should offer * RTP/SAVP instead of offering RTP/AVP. */ pjmedia_srtp_use peer_use; /* When probation counter > 0, it means SRTP is in probation state, * and it may restart when srtp_unprotect() returns err_status_replay_* */ unsigned probation_cnt; } transport_srtp; /* * This callback is called by transport when incoming rtp is received */ static void srtp_rtp_cb( void *user_data, void *pkt, pj_ssize_t size); /* * This callback is called by transport when incoming rtcp is received */ static void srtp_rtcp_cb( void *user_data, void *pkt, pj_ssize_t size); /* * These are media transport operations. */ static pj_status_t transport_get_info (pjmedia_transport *tp, pjmedia_transport_info *info); static pj_status_t transport_attach (pjmedia_transport *tp, void *user_data, const pj_sockaddr_t *rem_addr, const pj_sockaddr_t *rem_rtcp, unsigned addr_len, void (*rtp_cb)(void*, void*, pj_ssize_t), void (*rtcp_cb)(void*, void*, pj_ssize_t)); static void transport_detach (pjmedia_transport *tp, void *strm); static pj_status_t transport_send_rtp( pjmedia_transport *tp, const void *pkt, pj_size_t size); static pj_status_t transport_send_rtcp(pjmedia_transport *tp, const void *pkt, pj_size_t size); static pj_status_t transport_send_rtcp2(pjmedia_transport *tp, const pj_sockaddr_t *addr, unsigned addr_len, const void *pkt, pj_size_t size); static pj_status_t transport_media_create(pjmedia_transport *tp, pj_pool_t *sdp_pool, unsigned options, const pjmedia_sdp_session *sdp_remote, unsigned media_index); static pj_status_t transport_encode_sdp(pjmedia_transport *tp, pj_pool_t *sdp_pool, pjmedia_sdp_session *sdp_local, const pjmedia_sdp_session *sdp_remote, unsigned media_index); static pj_status_t transport_media_start (pjmedia_transport *tp, pj_pool_t *pool, const pjmedia_sdp_session *sdp_local, const pjmedia_sdp_session *sdp_remote, unsigned media_index); static pj_status_t transport_media_stop(pjmedia_transport *tp); static pj_status_t transport_simulate_lost(pjmedia_transport *tp, pjmedia_dir dir, unsigned pct_lost); static pj_status_t transport_destroy (pjmedia_transport *tp); static pjmedia_transport_op transport_srtp_op = { &transport_get_info, &transport_attach, &transport_detach, &transport_send_rtp, &transport_send_rtcp, &transport_send_rtcp2, &transport_media_create, &transport_encode_sdp, &transport_media_start, &transport_media_stop, &transport_simulate_lost, &transport_destroy }; /* This function may also be used by other module, e.g: pjmedia/errno.c, * it should have C compatible declaration. */ PJ_BEGIN_DECL const char* get_libsrtp_errstr(int err); PJ_END_DECL const char* get_libsrtp_errstr(int err) { #if defined(PJ_HAS_ERROR_STRING) && (PJ_HAS_ERROR_STRING != 0) static char *liberr[] = { "ok", /* err_status_ok = 0 */ "unspecified failure", /* err_status_fail = 1 */ "unsupported parameter", /* err_status_bad_param = 2 */ "couldn't allocate memory", /* err_status_alloc_fail = 3 */ "couldn't deallocate properly", /* err_status_dealloc_fail = 4 */ "couldn't initialize", /* err_status_init_fail = 5 */ "can't process as much data as requested", /* err_status_terminus = 6 */ "authentication failure", /* err_status_auth_fail = 7 */ "cipher failure", /* err_status_cipher_fail = 8 */ "replay check failed (bad index)", /* err_status_replay_fail = 9 */ "replay check failed (index too old)", /* err_status_replay_old = 10 */ "algorithm failed test routine", /* err_status_algo_fail = 11 */ "unsupported operation", /* err_status_no_such_op = 12 */ "no appropriate context found", /* err_status_no_ctx = 13 */ "unable to perform desired validation", /* err_status_cant_check = 14 */ "can't use key any more", /* err_status_key_expired = 15 */ "error in use of socket", /* err_status_socket_err = 16 */ "error in use POSIX signals", /* err_status_signal_err = 17 */ "nonce check failed", /* err_status_nonce_bad = 18 */ "couldn't read data", /* err_status_read_fail = 19 */ "couldn't write data", /* err_status_write_fail = 20 */ "error pasring data", /* err_status_parse_err = 21 */ "error encoding data", /* err_status_encode_err = 22 */ "error while using semaphores", /* err_status_semaphore_err = 23 */ "error while using pfkey" /* err_status_pfkey_err = 24 */ }; if (err >= 0 && err < (int)PJ_ARRAY_SIZE(liberr)) { return liberr[err]; } else { static char msg[32]; pj_ansi_snprintf(msg, sizeof(msg), "Unknown libsrtp error %d", err); return msg; } #else static char msg[32]; pj_ansi_snprintf(msg, sizeof(msg), "libsrtp error %d", err); return msg; #endif } static pj_bool_t libsrtp_initialized; static void pjmedia_srtp_deinit_lib(pjmedia_endpt *endpt); PJ_DEF(pj_status_t) pjmedia_srtp_init_lib(pjmedia_endpt *endpt) { if (libsrtp_initialized == PJ_FALSE) { err_status_t err; err = srtp_init(); if (err != err_status_ok) { PJ_LOG(4, (THIS_FILE, "Failed to initialize libsrtp: %s", get_libsrtp_errstr(err))); return PJMEDIA_ERRNO_FROM_LIBSRTP(err); } if (pjmedia_endpt_atexit(endpt, pjmedia_srtp_deinit_lib) != PJ_SUCCESS) { /* There will be memory leak when it fails to schedule libsrtp * deinitialization, however the memory leak could be harmless, * since in modern OS's memory used by an application is released * when the application terminates. */ PJ_LOG(4, (THIS_FILE, "Failed to register libsrtp deinit.")); } libsrtp_initialized = PJ_TRUE; } return PJ_SUCCESS; } static void pjmedia_srtp_deinit_lib(pjmedia_endpt *endpt) { err_status_t err; /* Note that currently this SRTP init/deinit is not equipped with * reference counter, it should be safe as normally there is only * one single instance of media endpoint and even if it isn't, the * pjmedia_transport_srtp_create() will invoke SRTP init (the only * drawback should be the delay described by #788). */ PJ_UNUSED_ARG(endpt); err = srtp_deinit(); if (err != err_status_ok) { PJ_LOG(4, (THIS_FILE, "Failed to deinitialize libsrtp: %s", get_libsrtp_errstr(err))); } libsrtp_initialized = PJ_FALSE; } static int get_crypto_idx(const pj_str_t* crypto_name) { int i; int cs_cnt = sizeof(crypto_suites)/sizeof(crypto_suites[0]); /* treat unspecified crypto_name as crypto 'NULL' */ if (crypto_name->slen == 0) return 0; for (i=0; ikey, &c2->key); if (r != 0) return r; r = pj_stricmp(&c1->name, &c2->name); if (r != 0) return r; return (c1->flags != c2->flags); } static pj_bool_t srtp_crypto_empty(const pjmedia_srtp_crypto* c) { return (c->name.slen==0 || c->key.slen==0); } PJ_DEF(void) pjmedia_srtp_setting_default(pjmedia_srtp_setting *opt) { unsigned i; pj_assert(opt); pj_bzero(opt, sizeof(pjmedia_srtp_setting)); opt->close_member_tp = PJ_TRUE; opt->use = PJMEDIA_SRTP_OPTIONAL; /* Copy default crypto-suites, but skip crypto 'NULL' */ opt->crypto_count = sizeof(crypto_suites)/sizeof(crypto_suites[0]) - 1; for (i=0; icrypto_count; ++i) opt->crypto[i].name = pj_str(crypto_suites[i+1].name); } /* * Create an SRTP media transport. */ PJ_DEF(pj_status_t) pjmedia_transport_srtp_create( pjmedia_endpt *endpt, pjmedia_transport *tp, const pjmedia_srtp_setting *opt, pjmedia_transport **p_tp) { pj_pool_t *pool; transport_srtp *srtp; pj_status_t status; unsigned i; PJ_ASSERT_RETURN(endpt && tp && p_tp, PJ_EINVAL); /* Check crypto availability */ if (opt && opt->crypto_count == 0 && opt->use == PJMEDIA_SRTP_MANDATORY) return PJMEDIA_SRTP_ESDPREQCRYPTO; /* Check crypto */ if (opt && opt->use != PJMEDIA_SRTP_DISABLED) { for (i=0; i < opt->crypto_count; ++i) { int cs_idx = get_crypto_idx(&opt->crypto[i].name); /* check crypto name */ if (cs_idx == -1) return PJMEDIA_SRTP_ENOTSUPCRYPTO; /* check key length */ if (opt->crypto[i].key.slen && opt->crypto[i].key.slen < (pj_ssize_t)crypto_suites[cs_idx].cipher_key_len) return PJMEDIA_SRTP_EINKEYLEN; } } /* Init libsrtp. */ status = pjmedia_srtp_init_lib(endpt); if (status != PJ_SUCCESS) return status; pool = pjmedia_endpt_create_pool(endpt, "srtp%p", 1000, 1000); srtp = PJ_POOL_ZALLOC_T(pool, transport_srtp); srtp->pool = pool; srtp->session_inited = PJ_FALSE; srtp->bypass_srtp = PJ_FALSE; srtp->probation_cnt = PROBATION_CNT_INIT; if (opt) { srtp->setting = *opt; if (opt->use == PJMEDIA_SRTP_DISABLED) srtp->setting.crypto_count = 0; for (i=0; i < srtp->setting.crypto_count; ++i) { int cs_idx = get_crypto_idx(&opt->crypto[i].name); pj_str_t tmp_key = opt->crypto[i].key; /* re-set crypto */ srtp->setting.crypto[i].name = pj_str(crypto_suites[cs_idx].name); /* cut key length */ if (tmp_key.slen) tmp_key.slen = crypto_suites[cs_idx].cipher_key_len; pj_strdup(pool, &srtp->setting.crypto[i].key, &tmp_key); } } else { pjmedia_srtp_setting_default(&srtp->setting); } status = pj_lock_create_recursive_mutex(pool, pool->obj_name, &srtp->mutex); if (status != PJ_SUCCESS) { pj_pool_release(pool); return status; } /* Initialize base pjmedia_transport */ pj_memcpy(srtp->base.name, pool->obj_name, PJ_MAX_OBJ_NAME); if (tp) srtp->base.type = tp->type; else srtp->base.type = PJMEDIA_TRANSPORT_TYPE_UDP; srtp->base.op = &transport_srtp_op; /* Set underlying transport */ srtp->member_tp = tp; /* Initialize peer's SRTP usage mode. */ srtp->peer_use = srtp->setting.use; /* Done */ *p_tp = &srtp->base; return PJ_SUCCESS; } /* * Initialize and start SRTP session with the given parameters. */ PJ_DEF(pj_status_t) pjmedia_transport_srtp_start( pjmedia_transport *tp, const pjmedia_srtp_crypto *tx, const pjmedia_srtp_crypto *rx) { transport_srtp *srtp = (transport_srtp*) tp; srtp_policy_t tx_; srtp_policy_t rx_; err_status_t err; int cr_tx_idx = 0; int au_tx_idx = 0; int cr_rx_idx = 0; int au_rx_idx = 0; int crypto_suites_cnt; pj_status_t status = PJ_SUCCESS; PJ_ASSERT_RETURN(tp && tx && rx, PJ_EINVAL); pj_lock_acquire(srtp->mutex); if (srtp->session_inited) { pjmedia_transport_srtp_stop(tp); } crypto_suites_cnt = sizeof(crypto_suites)/sizeof(crypto_suites[0]); /* Get encryption and authentication method */ cr_tx_idx = au_tx_idx = get_crypto_idx(&tx->name); if (tx->flags & PJMEDIA_SRTP_NO_ENCRYPTION) cr_tx_idx = 0; if (tx->flags & PJMEDIA_SRTP_NO_AUTHENTICATION) au_tx_idx = 0; cr_rx_idx = au_rx_idx = get_crypto_idx(&rx->name); if (rx->flags & PJMEDIA_SRTP_NO_ENCRYPTION) cr_rx_idx = 0; if (rx->flags & PJMEDIA_SRTP_NO_AUTHENTICATION) au_rx_idx = 0; /* Check whether the crypto-suite requested is supported */ if (cr_tx_idx == -1 || cr_rx_idx == -1 || au_tx_idx == -1 || au_rx_idx == -1) { status = PJMEDIA_SRTP_ENOTSUPCRYPTO; goto on_return; } /* If all options points to 'NULL' method, just bypass SRTP */ if (cr_tx_idx == 0 && cr_rx_idx == 0 && au_tx_idx == 0 && au_rx_idx == 0) { srtp->bypass_srtp = PJ_TRUE; goto on_return; } /* Check key length */ if (tx->key.slen != (pj_ssize_t)crypto_suites[cr_tx_idx].cipher_key_len || rx->key.slen != (pj_ssize_t)crypto_suites[cr_rx_idx].cipher_key_len) { status = PJMEDIA_SRTP_EINKEYLEN; goto on_return; } /* Init transmit direction */ pj_bzero(&tx_, sizeof(srtp_policy_t)); pj_memmove(srtp->tx_key, tx->key.ptr, tx->key.slen); if (cr_tx_idx && au_tx_idx) tx_.rtp.sec_serv = sec_serv_conf_and_auth; else if (cr_tx_idx) tx_.rtp.sec_serv = sec_serv_conf; else if (au_tx_idx) tx_.rtp.sec_serv = sec_serv_auth; else tx_.rtp.sec_serv = sec_serv_none; tx_.key = (uint8_t*)srtp->tx_key; tx_.ssrc.type = ssrc_any_outbound; tx_.ssrc.value = 0; tx_.rtp.cipher_type = crypto_suites[cr_tx_idx].cipher_type; tx_.rtp.cipher_key_len = crypto_suites[cr_tx_idx].cipher_key_len; tx_.rtp.auth_type = crypto_suites[au_tx_idx].auth_type; tx_.rtp.auth_key_len = crypto_suites[au_tx_idx].auth_key_len; tx_.rtp.auth_tag_len = crypto_suites[au_tx_idx].srtp_auth_tag_len; tx_.rtcp = tx_.rtp; tx_.rtcp.auth_tag_len = crypto_suites[au_tx_idx].srtcp_auth_tag_len; tx_.next = NULL; err = srtp_create(&srtp->srtp_tx_ctx, &tx_); if (err != err_status_ok) { status = PJMEDIA_ERRNO_FROM_LIBSRTP(err); goto on_return; } srtp->tx_policy = *tx; pj_strset(&srtp->tx_policy.key, srtp->tx_key, tx->key.slen); srtp->tx_policy.name=pj_str(crypto_suites[get_crypto_idx(&tx->name)].name); /* Init receive direction */ pj_bzero(&rx_, sizeof(srtp_policy_t)); pj_memmove(srtp->rx_key, rx->key.ptr, rx->key.slen); if (cr_rx_idx && au_rx_idx) rx_.rtp.sec_serv = sec_serv_conf_and_auth; else if (cr_rx_idx) rx_.rtp.sec_serv = sec_serv_conf; else if (au_rx_idx) rx_.rtp.sec_serv = sec_serv_auth; else rx_.rtp.sec_serv = sec_serv_none; rx_.key = (uint8_t*)srtp->rx_key; rx_.ssrc.type = ssrc_any_inbound; rx_.ssrc.value = 0; rx_.rtp.sec_serv = crypto_suites[cr_rx_idx].service; rx_.rtp.cipher_type = crypto_suites[cr_rx_idx].cipher_type; rx_.rtp.cipher_key_len = crypto_suites[cr_rx_idx].cipher_key_len; rx_.rtp.auth_type = crypto_suites[au_rx_idx].auth_type; rx_.rtp.auth_key_len = crypto_suites[au_rx_idx].auth_key_len; rx_.rtp.auth_tag_len = crypto_suites[au_rx_idx].srtp_auth_tag_len; rx_.rtcp = rx_.rtp; rx_.rtcp.auth_tag_len = crypto_suites[au_rx_idx].srtcp_auth_tag_len; rx_.next = NULL; err = srtp_create(&srtp->srtp_rx_ctx, &rx_); if (err != err_status_ok) { srtp_dealloc(srtp->srtp_tx_ctx); status = PJMEDIA_ERRNO_FROM_LIBSRTP(err); goto on_return; } srtp->rx_policy = *rx; pj_strset(&srtp->rx_policy.key, srtp->rx_key, rx->key.slen); srtp->rx_policy.name=pj_str(crypto_suites[get_crypto_idx(&rx->name)].name); /* Declare SRTP session initialized */ srtp->session_inited = PJ_TRUE; /* Logging stuffs */ #if PJ_LOG_MAX_LEVEL >= 5 { char b64[PJ_BASE256_TO_BASE64_LEN(MAX_KEY_LEN)]; int b64_len; /* TX crypto and key */ b64_len = sizeof(b64); status = pj_base64_encode((pj_uint8_t*)tx->key.ptr, tx->key.slen, b64, &b64_len); if (status != PJ_SUCCESS) b64_len = pj_ansi_sprintf(b64, "--key too long--"); else b64[b64_len] = '\0'; PJ_LOG(5, (srtp->pool->obj_name, "TX: %s key=%s", srtp->tx_policy.name.ptr, b64)); if (srtp->tx_policy.flags) { PJ_LOG(5,(srtp->pool->obj_name, "TX: disable%s%s", (cr_tx_idx?"":" enc"), (au_tx_idx?"":" auth"))); } /* RX crypto and key */ b64_len = sizeof(b64); status = pj_base64_encode((pj_uint8_t*)rx->key.ptr, rx->key.slen, b64, &b64_len); if (status != PJ_SUCCESS) b64_len = pj_ansi_sprintf(b64, "--key too long--"); else b64[b64_len] = '\0'; PJ_LOG(5, (srtp->pool->obj_name, "RX: %s key=%s", srtp->rx_policy.name.ptr, b64)); if (srtp->rx_policy.flags) { PJ_LOG(5,(srtp->pool->obj_name,"RX: disable%s%s", (cr_rx_idx?"":" enc"), (au_rx_idx?"":" auth"))); } } #endif on_return: pj_lock_release(srtp->mutex); return status; } /* * Stop SRTP session. */ PJ_DEF(pj_status_t) pjmedia_transport_srtp_stop(pjmedia_transport *srtp) { transport_srtp *p_srtp = (transport_srtp*) srtp; err_status_t err; PJ_ASSERT_RETURN(srtp, PJ_EINVAL); pj_lock_acquire(p_srtp->mutex); if (!p_srtp->session_inited) { pj_lock_release(p_srtp->mutex); return PJ_SUCCESS; } err = srtp_dealloc(p_srtp->srtp_rx_ctx); if (err != err_status_ok) { PJ_LOG(4, (p_srtp->pool->obj_name, "Failed to dealloc RX SRTP context: %s", get_libsrtp_errstr(err))); } err = srtp_dealloc(p_srtp->srtp_tx_ctx); if (err != err_status_ok) { PJ_LOG(4, (p_srtp->pool->obj_name, "Failed to dealloc TX SRTP context: %s", get_libsrtp_errstr(err))); } p_srtp->session_inited = PJ_FALSE; pj_bzero(&p_srtp->rx_policy, sizeof(p_srtp->rx_policy)); pj_bzero(&p_srtp->tx_policy, sizeof(p_srtp->tx_policy)); pj_lock_release(p_srtp->mutex); return PJ_SUCCESS; } PJ_DEF(pjmedia_transport *) pjmedia_transport_srtp_get_member( pjmedia_transport *tp) { transport_srtp *srtp = (transport_srtp*) tp; PJ_ASSERT_RETURN(tp, NULL); return srtp->member_tp; } static pj_status_t transport_get_info(pjmedia_transport *tp, pjmedia_transport_info *info) { transport_srtp *srtp = (transport_srtp*) tp; pjmedia_srtp_info srtp_info; int spc_info_idx; PJ_ASSERT_RETURN(tp && info, PJ_EINVAL); PJ_ASSERT_RETURN(info->specific_info_cnt < PJMEDIA_TRANSPORT_SPECIFIC_INFO_MAXCNT, PJ_ETOOMANY); PJ_ASSERT_RETURN(sizeof(pjmedia_srtp_info) <= PJMEDIA_TRANSPORT_SPECIFIC_INFO_MAXSIZE, PJ_ENOMEM); srtp_info.active = srtp->session_inited; srtp_info.rx_policy = srtp->rx_policy; srtp_info.tx_policy = srtp->tx_policy; srtp_info.use = srtp->setting.use; srtp_info.peer_use = srtp->peer_use; spc_info_idx = info->specific_info_cnt++; info->spc_info[spc_info_idx].type = PJMEDIA_TRANSPORT_TYPE_SRTP; info->spc_info[spc_info_idx].cbsize = sizeof(srtp_info); pj_memcpy(&info->spc_info[spc_info_idx].buffer, &srtp_info, sizeof(srtp_info)); return pjmedia_transport_get_info(srtp->member_tp, info); } static pj_status_t transport_attach(pjmedia_transport *tp, void *user_data, const pj_sockaddr_t *rem_addr, const pj_sockaddr_t *rem_rtcp, unsigned addr_len, void (*rtp_cb) (void*, void*, pj_ssize_t), void (*rtcp_cb)(void*, void*, pj_ssize_t)) { transport_srtp *srtp = (transport_srtp*) tp; pj_status_t status; PJ_ASSERT_RETURN(tp && rem_addr && addr_len, PJ_EINVAL); /* Save the callbacks */ pj_lock_acquire(srtp->mutex); srtp->rtp_cb = rtp_cb; srtp->rtcp_cb = rtcp_cb; srtp->user_data = user_data; pj_lock_release(srtp->mutex); /* Attach itself to transport */ status = pjmedia_transport_attach(srtp->member_tp, srtp, rem_addr, rem_rtcp, addr_len, &srtp_rtp_cb, &srtp_rtcp_cb); if (status != PJ_SUCCESS) { pj_lock_acquire(srtp->mutex); srtp->rtp_cb = NULL; srtp->rtcp_cb = NULL; srtp->user_data = NULL; pj_lock_release(srtp->mutex); return status; } return PJ_SUCCESS; } static void transport_detach(pjmedia_transport *tp, void *strm) { transport_srtp *srtp = (transport_srtp*) tp; PJ_UNUSED_ARG(strm); PJ_ASSERT_ON_FAIL(tp, return); if (srtp->member_tp) { pjmedia_transport_detach(srtp->member_tp, srtp); } /* Clear up application infos from transport */ pj_lock_acquire(srtp->mutex); srtp->rtp_cb = NULL; srtp->rtcp_cb = NULL; srtp->user_data = NULL; pj_lock_release(srtp->mutex); } static pj_status_t transport_send_rtp( pjmedia_transport *tp, const void *pkt, pj_size_t size) { pj_status_t status; transport_srtp *srtp = (transport_srtp*) tp; int len = size; err_status_t err; if (srtp->bypass_srtp) return pjmedia_transport_send_rtp(srtp->member_tp, pkt, size); if (size > sizeof(srtp->rtp_tx_buffer) - 10) return PJ_ETOOBIG; pj_memcpy(srtp->rtp_tx_buffer, pkt, size); pj_lock_acquire(srtp->mutex); if (!srtp->session_inited) { pj_lock_release(srtp->mutex); return PJ_EINVALIDOP; } err = srtp_protect(srtp->srtp_tx_ctx, srtp->rtp_tx_buffer, &len); pj_lock_release(srtp->mutex); if (err == err_status_ok) { status = pjmedia_transport_send_rtp(srtp->member_tp, srtp->rtp_tx_buffer, len); } else { status = PJMEDIA_ERRNO_FROM_LIBSRTP(err); } return status; } static pj_status_t transport_send_rtcp(pjmedia_transport *tp, const void *pkt, pj_size_t size) { return transport_send_rtcp2(tp, NULL, 0, pkt, size); } static pj_status_t transport_send_rtcp2(pjmedia_transport *tp, const pj_sockaddr_t *addr, unsigned addr_len, const void *pkt, pj_size_t size) { pj_status_t status; transport_srtp *srtp = (transport_srtp*) tp; int len = size; err_status_t err; if (srtp->bypass_srtp) { return pjmedia_transport_send_rtcp2(srtp->member_tp, addr, addr_len, pkt, size); } if (size > sizeof(srtp->rtcp_tx_buffer) - 10) return PJ_ETOOBIG; pj_memcpy(srtp->rtcp_tx_buffer, pkt, size); pj_lock_acquire(srtp->mutex); if (!srtp->session_inited) { pj_lock_release(srtp->mutex); return PJ_EINVALIDOP; } err = srtp_protect_rtcp(srtp->srtp_tx_ctx, srtp->rtcp_tx_buffer, &len); pj_lock_release(srtp->mutex); if (err == err_status_ok) { status = pjmedia_transport_send_rtcp2(srtp->member_tp, addr, addr_len, srtp->rtcp_tx_buffer, len); } else { status = PJMEDIA_ERRNO_FROM_LIBSRTP(err); } return status; } static pj_status_t transport_simulate_lost(pjmedia_transport *tp, pjmedia_dir dir, unsigned pct_lost) { transport_srtp *srtp = (transport_srtp *) tp; PJ_ASSERT_RETURN(tp, PJ_EINVAL); return pjmedia_transport_simulate_lost(srtp->member_tp, dir, pct_lost); } static pj_status_t transport_destroy (pjmedia_transport *tp) { transport_srtp *srtp = (transport_srtp *) tp; pj_status_t status; PJ_ASSERT_RETURN(tp, PJ_EINVAL); if (srtp->setting.close_member_tp && srtp->member_tp) { pjmedia_transport_close(srtp->member_tp); } status = pjmedia_transport_srtp_stop(tp); /* In case mutex is being acquired by other thread */ pj_lock_acquire(srtp->mutex); pj_lock_release(srtp->mutex); pj_lock_destroy(srtp->mutex); pj_pool_release(srtp->pool); return status; } /* * This callback is called by transport when incoming rtp is received */ static void srtp_rtp_cb( void *user_data, void *pkt, pj_ssize_t size) { transport_srtp *srtp = (transport_srtp *) user_data; int len = size; err_status_t err; void (*cb)(void*, void*, pj_ssize_t) = NULL; void *cb_data = NULL; if (srtp->bypass_srtp) { srtp->rtp_cb(srtp->user_data, pkt, size); return; } if (size < 0) { return; } /* Make sure buffer is 32bit aligned */ PJ_ASSERT_ON_FAIL( (((long)pkt) & 0x03)==0, return ); if (srtp->probation_cnt > 0) --srtp->probation_cnt; pj_lock_acquire(srtp->mutex); if (!srtp->session_inited) { pj_lock_release(srtp->mutex); return; } err = srtp_unprotect(srtp->srtp_rx_ctx, (pj_uint8_t*)pkt, &len); if (srtp->probation_cnt > 0 && (err == err_status_replay_old || err == err_status_replay_fail)) { /* Handle such condition that stream is updated (RTP seq is reinited * & SRTP is restarted), but some old packets are still coming * so SRTP is learning wrong RTP seq. While the newly inited RTP seq * comes, SRTP thinks the RTP seq is replayed, so srtp_unprotect() * will return err_status_replay_*. Restarting SRTP can resolve this. */ pjmedia_srtp_crypto tx, rx; pj_status_t status; tx = srtp->tx_policy; rx = srtp->rx_policy; status = pjmedia_transport_srtp_start((pjmedia_transport*)srtp, &tx, &rx); if (status != PJ_SUCCESS) { PJ_LOG(5,(srtp->pool->obj_name, "Failed to restart SRTP, err=%s", get_libsrtp_errstr(err))); } else if (!srtp->bypass_srtp) { err = srtp_unprotect(srtp->srtp_rx_ctx, (pj_uint8_t*)pkt, &len); } } if (err != err_status_ok) { PJ_LOG(5,(srtp->pool->obj_name, "Failed to unprotect SRTP, pkt size=%d, err=%s", size, get_libsrtp_errstr(err))); } else { cb = srtp->rtp_cb; cb_data = srtp->user_data; } pj_lock_release(srtp->mutex); if (cb) { (*cb)(cb_data, pkt, len); } } /* * This callback is called by transport when incoming rtcp is received */ static void srtp_rtcp_cb( void *user_data, void *pkt, pj_ssize_t size) { transport_srtp *srtp = (transport_srtp *) user_data; int len = size; err_status_t err; void (*cb)(void*, void*, pj_ssize_t) = NULL; void *cb_data = NULL; if (srtp->bypass_srtp) { srtp->rtcp_cb(srtp->user_data, pkt, size); return; } if (size < 0) { return; } /* Make sure buffer is 32bit aligned */ PJ_ASSERT_ON_FAIL( (((long)pkt) & 0x03)==0, return ); pj_lock_acquire(srtp->mutex); if (!srtp->session_inited) { pj_lock_release(srtp->mutex); return; } err = srtp_unprotect_rtcp(srtp->srtp_rx_ctx, (pj_uint8_t*)pkt, &len); if (err != err_status_ok) { PJ_LOG(5,(srtp->pool->obj_name, "Failed to unprotect SRTCP, pkt size=%d, err=%s", size, get_libsrtp_errstr(err))); } else { cb = srtp->rtcp_cb; cb_data = srtp->user_data; } pj_lock_release(srtp->mutex); if (cb) { (*cb)(cb_data, pkt, len); } } /* Generate crypto attribute, including crypto key. * If crypto-suite chosen is crypto NULL, just return PJ_SUCCESS, * and set buffer_len = 0. */ static pj_status_t generate_crypto_attr_value(pj_pool_t *pool, char *buffer, int *buffer_len, pjmedia_srtp_crypto *crypto, int tag) { pj_status_t status; int cs_idx = get_crypto_idx(&crypto->name); char b64_key[PJ_BASE256_TO_BASE64_LEN(MAX_KEY_LEN)+1]; int b64_key_len = sizeof(b64_key); if (cs_idx == -1) return PJMEDIA_SRTP_ENOTSUPCRYPTO; /* Crypto-suite NULL. */ if (cs_idx == 0) { *buffer_len = 0; return PJ_SUCCESS; } /* Generate key if not specified. */ if (crypto->key.slen == 0) { pj_bool_t key_ok; char key[MAX_KEY_LEN]; err_status_t err; unsigned i; PJ_ASSERT_RETURN(MAX_KEY_LEN >= crypto_suites[cs_idx].cipher_key_len, PJ_ETOOSMALL); do { key_ok = PJ_TRUE; err = crypto_get_random((unsigned char*)key, crypto_suites[cs_idx].cipher_key_len); if (err != err_status_ok) { PJ_LOG(5,(THIS_FILE, "Failed generating random key: %s", get_libsrtp_errstr(err))); return PJMEDIA_ERRNO_FROM_LIBSRTP(err); } for (i=0; ikey.ptr = (char*) pj_pool_zalloc(pool, crypto_suites[cs_idx].cipher_key_len); pj_memcpy(crypto->key.ptr, key, crypto_suites[cs_idx].cipher_key_len); crypto->key.slen = crypto_suites[cs_idx].cipher_key_len; } if (crypto->key.slen != (pj_ssize_t)crypto_suites[cs_idx].cipher_key_len) return PJMEDIA_SRTP_EINKEYLEN; /* Key transmitted via SDP should be base64 encoded. */ status = pj_base64_encode((pj_uint8_t*)crypto->key.ptr, crypto->key.slen, b64_key, &b64_key_len); if (status != PJ_SUCCESS) { PJ_LOG(5,(THIS_FILE, "Failed encoding plain key to base64")); return status; } b64_key[b64_key_len] = '\0'; PJ_ASSERT_RETURN(*buffer_len >= (crypto->name.slen + \ b64_key_len + 16), PJ_ETOOSMALL); /* Print the crypto attribute value. */ *buffer_len = pj_ansi_snprintf(buffer, *buffer_len, "%d %s inline:%s", tag, crypto_suites[cs_idx].name, b64_key); return PJ_SUCCESS; } /* Parse crypto attribute line */ static pj_status_t parse_attr_crypto(pj_pool_t *pool, const pjmedia_sdp_attr *attr, pjmedia_srtp_crypto *crypto, int *tag) { pj_str_t input; char *token; int token_len; pj_str_t tmp; pj_status_t status; int itmp; pj_bzero(crypto, sizeof(*crypto)); pj_strdup_with_null(pool, &input, &attr->value); /* Tag */ token = strtok(input.ptr, " "); if (!token) { PJ_LOG(4,(THIS_FILE, "Attribute crypto expecting tag")); return PJMEDIA_SDP_EINATTR; } token_len = pj_ansi_strlen(token); /* Tag must not use leading zeroes. */ if (token_len > 1 && *token == '0') return PJMEDIA_SDP_EINATTR; /* Tag must be decimal, i.e: contains only digit '0'-'9'. */ for (itmp = 0; itmp < token_len; ++itmp) if (!pj_isdigit(token[itmp])) return PJMEDIA_SDP_EINATTR; /* Get tag value. */ *tag = atoi(token); /* Crypto-suite */ token = strtok(NULL, " "); if (!token) { PJ_LOG(4,(THIS_FILE, "Attribute crypto expecting crypto suite")); return PJMEDIA_SDP_EINATTR; } crypto->name = pj_str(token); /* Key method */ token = strtok(NULL, ":"); if (!token) { PJ_LOG(4,(THIS_FILE, "Attribute crypto expecting key method")); return PJMEDIA_SDP_EINATTR; } if (pj_ansi_stricmp(token, "inline")) { PJ_LOG(4,(THIS_FILE, "Attribute crypto key method '%s' not supported!", token)); return PJMEDIA_SDP_EINATTR; } /* Key */ token = strtok(NULL, "| "); if (!token) { PJ_LOG(4,(THIS_FILE, "Attribute crypto expecting key")); return PJMEDIA_SDP_EINATTR; } tmp = pj_str(token); if (PJ_BASE64_TO_BASE256_LEN(tmp.slen) > MAX_KEY_LEN) { PJ_LOG(4,(THIS_FILE, "Key too long")); return PJMEDIA_SRTP_EINKEYLEN; } /* Decode key */ crypto->key.ptr = (char*) pj_pool_zalloc(pool, MAX_KEY_LEN); itmp = MAX_KEY_LEN; status = pj_base64_decode(&tmp, (pj_uint8_t*)crypto->key.ptr, &itmp); if (status != PJ_SUCCESS) { PJ_LOG(4,(THIS_FILE, "Failed decoding crypto key from base64")); return status; } crypto->key.slen = itmp; return PJ_SUCCESS; } static pj_status_t transport_media_create(pjmedia_transport *tp, pj_pool_t *sdp_pool, unsigned options, const pjmedia_sdp_session *sdp_remote, unsigned media_index) { struct transport_srtp *srtp = (struct transport_srtp*) tp; unsigned member_tp_option; PJ_ASSERT_RETURN(tp, PJ_EINVAL); pj_bzero(&srtp->rx_policy_neg, sizeof(srtp->rx_policy_neg)); pj_bzero(&srtp->tx_policy_neg, sizeof(srtp->tx_policy_neg)); srtp->media_option = options; member_tp_option = options | PJMEDIA_TPMED_NO_TRANSPORT_CHECKING; srtp->offerer_side = sdp_remote == NULL; /* Validations */ if (srtp->offerer_side) { if (srtp->setting.use == PJMEDIA_SRTP_DISABLED) goto BYPASS_SRTP; } else { pjmedia_sdp_media *m_rem; m_rem = sdp_remote->media[media_index]; /* Nothing to do on inactive media stream */ if (pjmedia_sdp_media_find_attr(m_rem, &ID_INACTIVE, NULL)) goto BYPASS_SRTP; /* Validate remote media transport based on SRTP usage option. */ switch (srtp->setting.use) { case PJMEDIA_SRTP_DISABLED: if (pj_stricmp(&m_rem->desc.transport, &ID_RTP_SAVP) == 0) return PJMEDIA_SRTP_ESDPINTRANSPORT; goto BYPASS_SRTP; case PJMEDIA_SRTP_OPTIONAL: break; case PJMEDIA_SRTP_MANDATORY: if (pj_stricmp(&m_rem->desc.transport, &ID_RTP_SAVP) != 0) return PJMEDIA_SRTP_ESDPINTRANSPORT; break; } } goto PROPAGATE_MEDIA_CREATE; BYPASS_SRTP: srtp->bypass_srtp = PJ_TRUE; member_tp_option &= ~PJMEDIA_TPMED_NO_TRANSPORT_CHECKING; PROPAGATE_MEDIA_CREATE: return pjmedia_transport_media_create(srtp->member_tp, sdp_pool, member_tp_option, sdp_remote, media_index); } static pj_status_t transport_encode_sdp(pjmedia_transport *tp, pj_pool_t *sdp_pool, pjmedia_sdp_session *sdp_local, const pjmedia_sdp_session *sdp_remote, unsigned media_index) { struct transport_srtp *srtp = (struct transport_srtp*) tp; pjmedia_sdp_media *m_rem, *m_loc; enum { MAXLEN = 512 }; char buffer[MAXLEN]; int buffer_len; pj_status_t status; pjmedia_sdp_attr *attr; pj_str_t attr_value; unsigned i, j; PJ_ASSERT_RETURN(tp && sdp_pool && sdp_local, PJ_EINVAL); pj_bzero(&srtp->rx_policy_neg, sizeof(srtp->rx_policy_neg)); pj_bzero(&srtp->tx_policy_neg, sizeof(srtp->tx_policy_neg)); srtp->offerer_side = sdp_remote == NULL; m_rem = sdp_remote ? sdp_remote->media[media_index] : NULL; m_loc = sdp_local->media[media_index]; /* Bypass if media transport is not RTP/AVP or RTP/SAVP */ if (pj_stricmp(&m_loc->desc.transport, &ID_RTP_AVP) != 0 && pj_stricmp(&m_loc->desc.transport, &ID_RTP_SAVP) != 0) goto BYPASS_SRTP; /* If the media is inactive, do nothing. */ /* No, we still need to process SRTP offer/answer even if the media is * marked as inactive, because the transport is still alive in this * case (e.g. for keep-alive). See: * http://trac.pjsip.org/repos/ticket/1079 */ /* if (pjmedia_sdp_media_find_attr(m_loc, &ID_INACTIVE, NULL) || (m_rem && pjmedia_sdp_media_find_attr(m_rem, &ID_INACTIVE, NULL))) goto BYPASS_SRTP; */ /* Check remote media transport & set local media transport * based on SRTP usage option. */ if (srtp->offerer_side) { /* Generate transport */ switch (srtp->setting.use) { case PJMEDIA_SRTP_DISABLED: goto BYPASS_SRTP; case PJMEDIA_SRTP_OPTIONAL: m_loc->desc.transport = (srtp->peer_use == PJMEDIA_SRTP_MANDATORY)? ID_RTP_SAVP : ID_RTP_AVP; break; case PJMEDIA_SRTP_MANDATORY: m_loc->desc.transport = ID_RTP_SAVP; break; } /* Generate crypto attribute if not yet */ if (pjmedia_sdp_media_find_attr(m_loc, &ID_CRYPTO, NULL) == NULL) { for (i=0; isetting.crypto_count; ++i) { /* Offer crypto-suites based on setting. */ buffer_len = MAXLEN; status = generate_crypto_attr_value(srtp->pool, buffer, &buffer_len, &srtp->setting.crypto[i], i+1); if (status != PJ_SUCCESS) return status; /* If buffer_len==0, just skip the crypto attribute. */ if (buffer_len) { pj_strset(&attr_value, buffer, buffer_len); attr = pjmedia_sdp_attr_create(srtp->pool, ID_CRYPTO.ptr, &attr_value); m_loc->attr[m_loc->attr_count++] = attr; } } } } else { /* Answerer side */ pj_assert(sdp_remote && m_rem); /* Generate transport */ switch (srtp->setting.use) { case PJMEDIA_SRTP_DISABLED: if (pj_stricmp(&m_rem->desc.transport, &ID_RTP_SAVP) == 0) return PJMEDIA_SRTP_ESDPINTRANSPORT; goto BYPASS_SRTP; case PJMEDIA_SRTP_OPTIONAL: m_loc->desc.transport = m_rem->desc.transport; break; case PJMEDIA_SRTP_MANDATORY: if (pj_stricmp(&m_rem->desc.transport, &ID_RTP_SAVP) != 0) return PJMEDIA_SRTP_ESDPINTRANSPORT; m_loc->desc.transport = ID_RTP_SAVP; break; } /* Generate crypto attribute if not yet */ if (pjmedia_sdp_media_find_attr(m_loc, &ID_CRYPTO, NULL) == NULL) { pjmedia_srtp_crypto tmp_rx_crypto; pj_bool_t has_crypto_attr = PJ_FALSE; int matched_idx = -1; int chosen_tag = 0; int tags[64]; /* assume no more than 64 crypto attrs in a media */ unsigned cr_attr_count = 0; /* Find supported crypto-suite, get the tag, and assign policy_local */ for (i=0; iattr_count; ++i) { if (pj_stricmp(&m_rem->attr[i]->name, &ID_CRYPTO) != 0) continue; has_crypto_attr = PJ_TRUE; status = parse_attr_crypto(srtp->pool, m_rem->attr[i], &tmp_rx_crypto, &tags[cr_attr_count]); if (status != PJ_SUCCESS) return status; /* Check duplicated tag */ for (j=0; jsetting.crypto_count; ++j) if (pj_stricmp(&tmp_rx_crypto.name, &srtp->setting.crypto[j].name) == 0) { int cs_idx = get_crypto_idx(&tmp_rx_crypto.name); /* Force to use test key */ /* bad keys for snom: */ //char *hex_test_key = "58b29c5c8f42308120ce857e439f2d" // "7810a8b10ad0b1446be5470faea496"; //char *hex_test_key = "20a26aac7ba062d356ff52b61e3993" // "ccb78078f12c64db94b9c294927fd0"; //pj_str_t *test_key = &srtp->setting.crypto[j].key; //char *raw_test_key = pj_pool_zalloc(srtp->pool, 64); //hex_string_to_octet_string( // raw_test_key, // hex_test_key, // strlen(hex_test_key)); //pj_strset(test_key, raw_test_key, // crypto_suites[cs_idx].cipher_key_len); /* EO Force to use test key */ if (tmp_rx_crypto.key.slen != (int)crypto_suites[cs_idx].cipher_key_len) return PJMEDIA_SRTP_EINKEYLEN; srtp->rx_policy_neg = tmp_rx_crypto; chosen_tag = tags[cr_attr_count]; matched_idx = j; break; } } cr_attr_count++; } /* Check crypto negotiation result */ switch (srtp->setting.use) { case PJMEDIA_SRTP_DISABLED: pj_assert(!"Should never reach here"); break; case PJMEDIA_SRTP_OPTIONAL: /* bypass SRTP when no crypto-attr and remote uses RTP/AVP */ if (!has_crypto_attr && pj_stricmp(&m_rem->desc.transport, &ID_RTP_AVP) == 0) goto BYPASS_SRTP; /* bypass SRTP when nothing match and remote uses RTP/AVP */ else if (matched_idx == -1 && pj_stricmp(&m_rem->desc.transport, &ID_RTP_AVP) == 0) goto BYPASS_SRTP; break; case PJMEDIA_SRTP_MANDATORY: /* Do nothing, intentional */ break; } /* No crypto attr */ if (!has_crypto_attr) { DEACTIVATE_MEDIA(sdp_pool, m_loc); return PJMEDIA_SRTP_ESDPREQCRYPTO; } /* No crypto match */ if (matched_idx == -1) { DEACTIVATE_MEDIA(sdp_pool, m_loc); return PJMEDIA_SRTP_ENOTSUPCRYPTO; } /* we have to generate crypto answer, * with srtp->tx_policy_neg matched the offer * and rem_tag contains matched offer tag. */ buffer_len = MAXLEN; status = generate_crypto_attr_value(srtp->pool, buffer, &buffer_len, &srtp->setting.crypto[matched_idx], chosen_tag); if (status != PJ_SUCCESS) return status; srtp->tx_policy_neg = srtp->setting.crypto[matched_idx]; /* If buffer_len==0, just skip the crypto attribute. */ if (buffer_len) { pj_strset(&attr_value, buffer, buffer_len); attr = pjmedia_sdp_attr_create(sdp_pool, ID_CRYPTO.ptr, &attr_value); m_loc->attr[m_loc->attr_count++] = attr; } /* At this point, we get valid rx_policy_neg & tx_policy_neg. */ } } goto PROPAGATE_MEDIA_CREATE; BYPASS_SRTP: /* Do not update this flag here as actually the media session hasn't been * updated. */ //srtp->bypass_srtp = PJ_TRUE; PROPAGATE_MEDIA_CREATE: return pjmedia_transport_encode_sdp(srtp->member_tp, sdp_pool, sdp_local, sdp_remote, media_index); } static pj_status_t transport_media_start(pjmedia_transport *tp, pj_pool_t *pool, const pjmedia_sdp_session *sdp_local, const pjmedia_sdp_session *sdp_remote, unsigned media_index) { struct transport_srtp *srtp = (struct transport_srtp*) tp; pjmedia_sdp_media *m_rem, *m_loc; pj_status_t status; unsigned i; PJ_ASSERT_RETURN(tp && pool && sdp_local && sdp_remote, PJ_EINVAL); m_rem = sdp_remote->media[media_index]; m_loc = sdp_local->media[media_index]; if (pj_stricmp(&m_rem->desc.transport, &ID_RTP_SAVP) == 0) srtp->peer_use = PJMEDIA_SRTP_MANDATORY; else srtp->peer_use = PJMEDIA_SRTP_OPTIONAL; /* For answerer side, this function will just have to start SRTP */ /* Check remote media transport & set local media transport * based on SRTP usage option. */ if (srtp->offerer_side) { if (srtp->setting.use == PJMEDIA_SRTP_DISABLED) { if (pjmedia_sdp_media_find_attr(m_rem, &ID_CRYPTO, NULL)) { DEACTIVATE_MEDIA(pool, m_loc); return PJMEDIA_SRTP_ESDPINCRYPTO; } goto BYPASS_SRTP; } else if (srtp->setting.use == PJMEDIA_SRTP_OPTIONAL) { // Regardless the answer's transport type (RTP/AVP or RTP/SAVP), // the answer must be processed through in optional mode. // Please note that at this point transport type is ensured to be // RTP/AVP or RTP/SAVP, see transport_media_create() //if (pj_stricmp(&m_rem->desc.transport, &m_loc->desc.transport)) { //DEACTIVATE_MEDIA(pool, m_loc); //return PJMEDIA_SDP_EINPROTO; //} } else if (srtp->setting.use == PJMEDIA_SRTP_MANDATORY) { if (pj_stricmp(&m_rem->desc.transport, &ID_RTP_SAVP)) { DEACTIVATE_MEDIA(pool, m_loc); return PJMEDIA_SDP_EINPROTO; } } } if (srtp->offerer_side) { /* find supported crypto-suite, get the tag, and assign policy_local */ pjmedia_srtp_crypto tmp_tx_crypto; pj_bool_t has_crypto_attr = PJ_FALSE; int rem_tag; for (i=0; iattr_count; ++i) { if (pj_stricmp(&m_rem->attr[i]->name, &ID_CRYPTO) != 0) continue; /* more than one crypto attribute in media answer */ if (has_crypto_attr) { DEACTIVATE_MEDIA(pool, m_loc); return PJMEDIA_SRTP_ESDPAMBIGUEANS; } has_crypto_attr = PJ_TRUE; status = parse_attr_crypto(srtp->pool, m_rem->attr[i], &tmp_tx_crypto, &rem_tag); if (status != PJ_SUCCESS) return status; /* our offer tag is always ordered by setting */ if (rem_tag < 1 || rem_tag > (int)srtp->setting.crypto_count) { DEACTIVATE_MEDIA(pool, m_loc); return PJMEDIA_SRTP_ESDPINCRYPTOTAG; } /* match the crypto name */ if (pj_stricmp(&tmp_tx_crypto.name, &srtp->setting.crypto[rem_tag-1].name) != 0) { DEACTIVATE_MEDIA(pool, m_loc); return PJMEDIA_SRTP_ECRYPTONOTMATCH; } srtp->tx_policy_neg = srtp->setting.crypto[rem_tag-1]; srtp->rx_policy_neg = tmp_tx_crypto; } if (srtp->setting.use == PJMEDIA_SRTP_DISABLED) { /* should never reach here */ goto BYPASS_SRTP; } else if (srtp->setting.use == PJMEDIA_SRTP_OPTIONAL) { if (!has_crypto_attr) goto BYPASS_SRTP; } else if (srtp->setting.use == PJMEDIA_SRTP_MANDATORY) { if (!has_crypto_attr) { DEACTIVATE_MEDIA(pool, m_loc); return PJMEDIA_SRTP_ESDPREQCRYPTO; } } /* At this point, we get valid rx_policy_neg & tx_policy_neg. */ } /* Make sure we have the SRTP policies */ if (srtp_crypto_empty(&srtp->tx_policy_neg) || srtp_crypto_empty(&srtp->rx_policy_neg)) { goto BYPASS_SRTP; } /* Reset probation counts */ srtp->probation_cnt = PROBATION_CNT_INIT; /* Got policy_local & policy_remote, let's initalize the SRTP */ /* Ticket #1075: media_start() is called whenever media description * gets updated, e.g: call hold, however we should restart SRTP only * when the SRTP policy settings are updated. */ if (srtp_crypto_cmp(&srtp->tx_policy_neg, &srtp->tx_policy) || srtp_crypto_cmp(&srtp->rx_policy_neg, &srtp->rx_policy)) { status = pjmedia_transport_srtp_start(tp, &srtp->tx_policy_neg, &srtp->rx_policy_neg); if (status != PJ_SUCCESS) return status; } srtp->bypass_srtp = PJ_FALSE; goto PROPAGATE_MEDIA_START; BYPASS_SRTP: srtp->bypass_srtp = PJ_TRUE; srtp->peer_use = PJMEDIA_SRTP_DISABLED; if (srtp->session_inited) { pjmedia_transport_srtp_stop(tp); } PROPAGATE_MEDIA_START: return pjmedia_transport_media_start(srtp->member_tp, pool, sdp_local, sdp_remote, media_index); } static pj_status_t transport_media_stop(pjmedia_transport *tp) { struct transport_srtp *srtp = (struct transport_srtp*) tp; pj_status_t status; PJ_ASSERT_RETURN(tp, PJ_EINVAL); status = pjmedia_transport_media_stop(srtp->member_tp); if (status != PJ_SUCCESS) PJ_LOG(4, (srtp->pool->obj_name, "SRTP failed stop underlying media transport.")); return pjmedia_transport_srtp_stop(tp); } /* Utility */ PJ_DEF(pj_status_t) pjmedia_transport_srtp_decrypt_pkt(pjmedia_transport *tp, pj_bool_t is_rtp, void *pkt, int *pkt_len) { transport_srtp *srtp = (transport_srtp *)tp; err_status_t err; if (srtp->bypass_srtp) return PJ_SUCCESS; PJ_ASSERT_RETURN(tp && pkt && (*pkt_len>0), PJ_EINVAL); PJ_ASSERT_RETURN(srtp->session_inited, PJ_EINVALIDOP); /* Make sure buffer is 32bit aligned */ PJ_ASSERT_ON_FAIL( (((long)pkt) & 0x03)==0, return PJ_EINVAL); pj_lock_acquire(srtp->mutex); if (!srtp->session_inited) { pj_lock_release(srtp->mutex); return PJ_EINVALIDOP; } if (is_rtp) err = srtp_unprotect(srtp->srtp_rx_ctx, pkt, pkt_len); else err = srtp_unprotect_rtcp(srtp->srtp_rx_ctx, pkt, pkt_len); if (err != err_status_ok) { PJ_LOG(5,(srtp->pool->obj_name, "Failed to unprotect SRTP, pkt size=%d, err=%s", *pkt_len, get_libsrtp_errstr(err))); } pj_lock_release(srtp->mutex); return (err==err_status_ok) ? PJ_SUCCESS : PJMEDIA_ERRNO_FROM_LIBSRTP(err); } #endif