diff options
Diffstat (limited to 'pjmedia/src/pjmedia/transport_srtp.c')
-rw-r--r-- | pjmedia/src/pjmedia/transport_srtp.c | 1253 |
1 files changed, 1253 insertions, 0 deletions
diff --git a/pjmedia/src/pjmedia/transport_srtp.c b/pjmedia/src/pjmedia/transport_srtp.c new file mode 100644 index 00000000..405f72c2 --- /dev/null +++ b/pjmedia/src/pjmedia/transport_srtp.c @@ -0,0 +1,1253 @@ +/* $Id$ */ +/* + * Copyright (C) 2003-2007 Benny Prijono <benny@prijono.org> + * + * 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 <pjmedia/transport_srtp.h> +#include <pjmedia/endpoint.h> +#include <pjlib-util/base64.h> +#include <pj/assert.h> +#include <pj/lock.h> +#include <pj/log.h> +#include <pj/os.h> +#include <pj/pool.h> + +#if defined(PJMEDIA_HAS_SRTP) && (PJMEDIA_HAS_SRTP != 0) + +#include <srtp.h> + +#define THIS_FILE "transport_srtp.c" + +/* Maximum size of packet */ +#define MAX_BUFFER_LEN 1500 +#define MAX_KEY_LEN 32 +#define DEACTIVATE_MEDIA(pool, m) {\ + attr = pjmedia_sdp_attr_create(pool, ID_INACTIVE.ptr, NULL); \ + m->attr[m->attr_count++] = attr; \ + m->desc.port = 0; \ + } + +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; + pj_lock_t *mutex; + char tx_buffer[MAX_BUFFER_LEN]; + char rx_buffer[MAX_BUFFER_LEN]; + + pjmedia_srtp_setting setting; + /* 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; + + /* libSRTP contexts */ + srtp_t srtp_tx_ctx; + srtp_t srtp_rx_ctx; + + /* Stream information */ + void *user_data; + void (*rtp_cb)( void *user_data, + const void *pkt, + pj_ssize_t size); + void (*rtcp_cb)(void *user_data, + const void *pkt, + pj_ssize_t size); + + /* Transport information */ + pjmedia_transport *real_tp; /**< Underlying transport. */ + +} transport_srtp; + + +/* + * This callback is called by transport when incoming rtp is received + */ +static void srtp_rtp_cb( void *user_data, const 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, const void *pkt, pj_ssize_t size); + + +/* + * These are media transport operations. + */ +static pj_status_t transport_get_info (pjmedia_transport *tp, + pjmedia_sock_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*, + const void*, + pj_ssize_t), + void (*rtcp_cb)(void*, + const 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_media_create(pjmedia_transport *tp, + pj_pool_t *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, + 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_media_create, + &transport_media_start, + &transport_media_stop, + &transport_simulate_lost, + &transport_destroy +}; + +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 */ + }; + return liberr[err]; +#else + return NULL; +#endif +} + +static pj_status_t pjmedia_srtp_init_lib(void) +{ + static pj_bool_t initialized = PJ_FALSE; + + if (initialized == PJ_FALSE) { + err_status_t err; + err = srtp_init(); + if (err != err_status_ok) { + PJ_LOG(4, (THIS_FILE, "Failed to init libsrtp.")); + return PJMEDIA_ERRNO_FROM_LIBSRTP(err); + } + + initialized = PJ_TRUE; + } + + return PJ_SUCCESS; +} + +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; i<cs_cnt; ++i) { + if (!pj_stricmp2(crypto_name, crypto_suites[i].name)) + return i; + } + + return -1; +} + +PJ_DEF(void) pjmedia_srtp_setting_default(pjmedia_srtp_setting *opt) +{ + int i; + + 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; i<opt->crypto_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; + int i; + + PJ_ASSERT_RETURN(endpt && p_tp, PJ_EINVAL); + + /* Check crypto availability */ + if (opt->crypto_count == 0 && + opt->use == PJMEDIA_SRTP_MANDATORY) + return PJMEDIA_SRTP_ESDPREQCRYPTO; + + /* Check crypto */ + if (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(); + 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; + + 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); + srtp->base.type = tp->type; + srtp->base.op = &transport_srtp_op; + + /* Set underlying transport */ + srtp->real_tp = tp; + + /* 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; + + if (srtp->session_inited) { + PJ_LOG(4, (THIS_FILE, "SRTP could not be re-init'd before deinit'd")); + return PJ_EINVALIDOP; + } + + 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) + return PJMEDIA_SRTP_ENOTSUPCRYPTO; + + /* 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; + return PJ_SUCCESS; + } + + /* 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) + return PJMEDIA_SRTP_EINKEYLEN; + + /* 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) { + return PJMEDIA_ERRNO_FROM_LIBSRTP(err); + } + 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); + return PJMEDIA_ERRNO_FROM_LIBSRTP(err); + } + 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; + + PJ_LOG(5, (THIS_FILE, "TX: %s key=%s", srtp->tx_policy.name.ptr, + octet_string_hex_string(tx->key.ptr, tx->key.slen))); + if (srtp->tx_policy.flags) { + PJ_LOG(5, (THIS_FILE, "TX: disable%s%s", (cr_tx_idx?"":" enc"), + (au_tx_idx?"":" auth"))); + } + + PJ_LOG(5, (THIS_FILE, "RX: %s key=%s", srtp->rx_policy.name.ptr, + octet_string_hex_string(rx->key.ptr, rx->key.slen))); + if (srtp->rx_policy.flags) { + PJ_LOG(5, (THIS_FILE, "RX: disable%s%s", (cr_rx_idx?"":" enc"), + (au_rx_idx?"":" auth"))); + } + + return PJ_SUCCESS; +} + +/* + * 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; + + if (!p_srtp->session_inited) + return PJ_SUCCESS; + + err = srtp_dealloc(p_srtp->srtp_rx_ctx); + if (err != err_status_ok) { + PJ_LOG(4, (THIS_FILE, "Failed to dealloc RX SRTP context")); + } + err = srtp_dealloc(p_srtp->srtp_tx_ctx); + if (err != err_status_ok) { + PJ_LOG(4, (THIS_FILE, "Failed to dealloc TX SRTP context")); + } + + p_srtp->session_inited = PJ_FALSE; + + 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->real_tp; +} + + +static pj_status_t transport_get_info(pjmedia_transport *tp, + pjmedia_sock_info *info) +{ + transport_srtp *srtp = (transport_srtp*) tp; + + /* put SRTP info as well? */ + return pjmedia_transport_get_info(srtp->real_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*, const void*, + pj_ssize_t), + void (*rtcp_cb)(void*, const void*, + pj_ssize_t)) +{ + transport_srtp *srtp = (transport_srtp*) tp; + pj_status_t status; + + /* Attach itself to transport */ + status = pjmedia_transport_attach(srtp->real_tp, srtp, rem_addr, rem_rtcp, + addr_len, &srtp_rtp_cb, &srtp_rtcp_cb); + if (status != PJ_SUCCESS) + return status; + + /* Save the callbacks */ + srtp->rtp_cb = rtp_cb; + srtp->rtcp_cb = rtcp_cb; + srtp->user_data = user_data; + + return status; +} + +static void transport_detach(pjmedia_transport *tp, void *strm) +{ + transport_srtp *srtp = (transport_srtp*) tp; + + PJ_ASSERT_ON_FAIL(tp && srtp->real_tp, return); + + PJ_UNUSED_ARG(strm); + pjmedia_transport_detach(srtp->real_tp, srtp); + + /* Clear up application infos from transport */ + srtp->rtp_cb = NULL; + srtp->rtcp_cb = NULL; + srtp->user_data = NULL; +} + +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->real_tp, pkt, size); + + if (!srtp->session_inited) + return PJ_SUCCESS; + + if (size > sizeof(srtp->tx_buffer)) + return PJ_ETOOBIG; + + pj_lock_acquire(srtp->mutex); + pj_memcpy(srtp->tx_buffer, pkt, size); + + err = srtp_protect(srtp->srtp_tx_ctx, srtp->tx_buffer, &len); + if (err == err_status_ok) { + status = pjmedia_transport_send_rtp(srtp->real_tp, srtp->tx_buffer, len); + } else { + status = PJMEDIA_ERRNO_FROM_LIBSRTP(err); + } + + pj_lock_release(srtp->mutex); + + return status; +} + +static pj_status_t transport_send_rtcp(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_rtcp(srtp->real_tp, pkt, size); + + if (!srtp->session_inited) + return PJ_SUCCESS; + + if (size > sizeof(srtp->tx_buffer)) + return PJ_ETOOBIG; + + pj_lock_acquire(srtp->mutex); + pj_memcpy(srtp->tx_buffer, pkt, size); + + err = srtp_protect_rtcp(srtp->srtp_tx_ctx, srtp->tx_buffer, &len); + + if (err == err_status_ok) { + status = pjmedia_transport_send_rtcp(srtp->real_tp, srtp->tx_buffer, + len); + } else { + status = PJMEDIA_ERRNO_FROM_LIBSRTP(err); + } + + pj_lock_release(srtp->mutex); + + return status; +} + +static pj_status_t transport_simulate_lost(pjmedia_transport *tp, + pjmedia_dir dir, + unsigned pct_lost) +{ + transport_srtp *srtp = (transport_srtp *) tp; + + return pjmedia_transport_simulate_lost(srtp->real_tp, dir, pct_lost); +} + +static pj_status_t transport_destroy (pjmedia_transport *tp) +{ + transport_srtp *srtp = (transport_srtp *) tp; + pj_status_t status; + + pj_lock_acquire(srtp->mutex); + + pjmedia_transport_detach(tp, NULL); + + if (srtp->setting.close_member_tp) { + pjmedia_transport_close(srtp->real_tp); + } + + status = pjmedia_transport_srtp_stop(tp); + + 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, const void *pkt, pj_ssize_t size) +{ + transport_srtp *srtp = (transport_srtp *) user_data; + int len = size; + err_status_t err; + + if (srtp->bypass_srtp) { + srtp->rtp_cb(srtp->user_data, pkt, size); + return; + } + + if (size < 0 || size > sizeof(srtp->rx_buffer) || !srtp->session_inited) { + return; + } + + pj_lock_acquire(srtp->mutex); + pj_memcpy(srtp->rx_buffer, pkt, size); + + err = srtp_unprotect(srtp->srtp_rx_ctx, srtp->rx_buffer, &len); + + if (err == err_status_ok) { + srtp->rtp_cb(srtp->user_data, srtp->rx_buffer, len); + } else { + PJ_LOG(5, (THIS_FILE, "Failed to unprotect SRTP size=%d, err=%d", + size, err)); + } + + pj_lock_release(srtp->mutex); +} + +/* + * This callback is called by transport when incoming rtcp is received + */ +static void srtp_rtcp_cb( void *user_data, const void *pkt, pj_ssize_t size) +{ + transport_srtp *srtp = (transport_srtp *) user_data; + int len = size; + err_status_t err; + + if (srtp->bypass_srtp) { + srtp->rtcp_cb(srtp->user_data, pkt, size); + return; + } + + if (size < 0 || size > sizeof(srtp->rx_buffer) || !srtp->session_inited) { + return; + } + + pj_lock_acquire(srtp->mutex); + pj_memcpy(srtp->rx_buffer, pkt, size); + + err = srtp_unprotect_rtcp(srtp->srtp_rx_ctx, srtp->rx_buffer, &len); + + if (err == err_status_ok) { + srtp->rtcp_cb(srtp->user_data, srtp->rx_buffer, len); + } else { + PJ_LOG(5, (THIS_FILE, "Failed to unprotect SRTCP size=%d, err=%d", + size, err)); + } + + pj_lock_release(srtp->mutex); +} + +/* 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; + int 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")); + return PJMEDIA_ERRNO_FROM_LIBSRTP(err); + } + for (i=0; i<crypto_suites[cs_idx].cipher_key_len && key_ok; ++i) + if (key[i] == 0) key_ok = PJ_FALSE; + + } while (!key_ok); + crypto->key.ptr = 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; + 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; + } + *tag = atoi(token); + if (*tag == 0) + return PJMEDIA_SDP_EINATTR; + + /* 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); + crypto->key.ptr = pj_pool_zalloc(pool, MAX_KEY_LEN); + + /* Decode key */ + 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 *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; + int i, j; + + PJ_ASSERT_RETURN(tp && pool && sdp_local, PJ_EINVAL); + + pj_bzero(&srtp->rx_policy, sizeof(srtp->tx_policy)); + pj_bzero(&srtp->tx_policy, sizeof(srtp->rx_policy)); + + 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. */ + 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; + } + + srtp->offerer_side = !sdp_remote; + + /* Check remote media transport & set local media transport + * based on SRTP usage option. + */ + if (srtp->offerer_side) { + if (srtp->setting.use == PJMEDIA_SRTP_DISABLED) { + goto BYPASS_SRTP; + } else if (srtp->setting.use == PJMEDIA_SRTP_OPTIONAL) { + m_loc->desc.transport = ID_RTP_AVP; + } else if (srtp->setting.use == PJMEDIA_SRTP_MANDATORY) { + m_loc->desc.transport = ID_RTP_SAVP; + } + } else { + if (srtp->setting.use == PJMEDIA_SRTP_DISABLED) { + if (pj_stricmp(&m_rem->desc.transport, &ID_RTP_SAVP) == 0) { + DEACTIVATE_MEDIA(pool, m_loc); + return PJMEDIA_SRTP_ESDPINTRANSPORT; + } + } else if (srtp->setting.use == PJMEDIA_SRTP_OPTIONAL) { + m_loc->desc.transport = m_rem->desc.transport; + } else if (srtp->setting.use == PJMEDIA_SRTP_MANDATORY) { + if (pj_stricmp(&m_rem->desc.transport, &ID_RTP_SAVP) != 0) { + DEACTIVATE_MEDIA(pool, m_loc); + return PJMEDIA_SRTP_ESDPINTRANSPORT; + } + m_loc->desc.transport = ID_RTP_SAVP; + } + } + + /* Generate crypto attribute */ + if (srtp->offerer_side) { + for (i=0; i<srtp->setting.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 { + /* find supported crypto-suite, get the tag, and assign policy_local */ + pjmedia_srtp_crypto tmp_rx_crypto; + pj_bool_t has_crypto_attr = PJ_FALSE; + pj_bool_t has_match = PJ_FALSE; + int chosen_tag = 0; + int tags[64]; /* assume no more than 64 crypto attrs in a media */ + int cr_attr_count = 0; + int k; + + for (i=0; i<m_rem->attr_count; ++i) { + if (pj_stricmp(&m_rem->attr[i]->name, &ID_CRYPTO) != 0) + continue; + + /* SRTP is disabled but there is crypto attr in remote media */ + /* Put the checking here to save a bit memory for parsing */ + if (srtp->setting.use == PJMEDIA_SRTP_DISABLED) { + DEACTIVATE_MEDIA(pool, m_loc); + return PJMEDIA_SRTP_ESDPINTRANSPORT; + } + + 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 (k=0; k<cr_attr_count; ++k) { + if (tags[k] == tags[cr_attr_count]) { + DEACTIVATE_MEDIA(pool, m_loc); + return PJMEDIA_SRTP_ESDPDUPCRYPTOTAG; + } + } + + if (!has_match) { + /* lets see if the crypto-suite offered is supported */ + for (j=0; j<srtp->setting.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 */ + //char *hex_test_key = "58b29c5c8f42308120ce857e439f2d" + // "7810a8b10ad0b1446be5470faea496"; + //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); + + if (tmp_rx_crypto.key.slen != + (int)crypto_suites[cs_idx].cipher_key_len) + return PJMEDIA_SRTP_EINKEYLEN; + + srtp->tx_policy = srtp->setting.crypto[j]; + srtp->rx_policy = tmp_rx_crypto; + chosen_tag = tags[cr_attr_count]; + has_match = PJ_TRUE; + break; + } + } + cr_attr_count++; + } + + if (srtp->setting.use == PJMEDIA_SRTP_DISABLED) { + /* At this point, it is ensured remote has no crypto attr */ + goto BYPASS_SRTP; + } else if (srtp->setting.use == PJMEDIA_SRTP_OPTIONAL) { + /* bypass SRTP when no crypto-attr but 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 but remote uses RTP/AVP */ + if (!has_match && + pj_stricmp(&m_rem->desc.transport, &ID_RTP_AVP) == 0) + goto BYPASS_SRTP; + } else if (srtp->setting.use == PJMEDIA_SRTP_MANDATORY) { + /* do nothing, this is intended */ + } + + /* No crypto attr */ + if (!has_crypto_attr) { + DEACTIVATE_MEDIA(pool, m_loc); + return PJMEDIA_SRTP_ESDPREQCRYPTO; + } + + /* No crypto match */ + if (!has_match) { + DEACTIVATE_MEDIA(pool, m_loc); + return PJMEDIA_SRTP_ENOTSUPCRYPTO; + } + + /* we have to generate crypto answer, + * with srtp->tx_policy matched the offer + * and rem_tag contains matched offer tag. + */ + buffer_len = MAXLEN; + status = generate_crypto_attr_value(srtp->pool, buffer, &buffer_len, + &srtp->tx_policy, + chosen_tag); + 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; + } + + /* At this point, + * we should have valid rx_policy & tx_policy. + */ + } + goto PROPAGATE_MEDIA_CREATE; + +BYPASS_SRTP: + srtp->bypass_srtp = PJ_TRUE; + +PROPAGATE_MEDIA_CREATE: + return pjmedia_transport_media_create(srtp->real_tp, pool, sdp_local, + sdp_remote, media_index); +} + + + +static pj_status_t transport_media_start(pjmedia_transport *tp, + pj_pool_t *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; + pj_status_t status; + pjmedia_sdp_attr *attr; + int i; + + PJ_ASSERT_RETURN(tp && pool && sdp_local && sdp_remote, PJ_EINVAL); + + if (srtp->bypass_srtp) + goto BYPASS_SRTP; + + m_rem = sdp_remote->media[media_index]; + m_loc = sdp_local->media[media_index]; + + /* 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) { + 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; i<m_rem->attr_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 > 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 = srtp->setting.crypto[rem_tag-1]; + srtp->rx_policy = 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 should have valid rx_policy & tx_policy. + */ + } + + /* Got policy_local & policy_remote, let's initalize the SRTP */ + status = pjmedia_transport_srtp_start(tp, &srtp->tx_policy, &srtp->rx_policy); + if (status != PJ_SUCCESS) + return status; + + goto PROPAGATE_MEDIA_START; + +BYPASS_SRTP: + srtp->bypass_srtp = PJ_TRUE; + +PROPAGATE_MEDIA_START: + return pjmedia_transport_media_start(srtp->real_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; + + status = pjmedia_transport_media_stop(srtp->real_tp); + if (status != PJ_SUCCESS) + PJ_LOG(4, (THIS_FILE, "SRTP failed stop underlying media transport.")); + + return pjmedia_transport_srtp_stop(tp); +} + +#endif + + |