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/* $Id$ */
/*
* Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
* Copyright (C) 2003-2008 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/ctype.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 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; i<cs_cnt; ++i) {
if (!pj_stricmp2(crypto_name, crypto_suites[i].name))
return i;
}
return -1;
}
static int srtp_crypto_cmp(const pjmedia_srtp_crypto* c1,
const pjmedia_srtp_crypto* c2)
{
int r;
r = pj_strcmp(&c1->key, &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; 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;
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 = (int)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 = (int)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( (((pj_ssize_t)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( (((pj_ssize_t)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);
int print_len;
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; 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 = (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. */
print_len = pj_ansi_snprintf(buffer, *buffer_len, "%d %s inline:%s",
tag,
crypto_suites[cs_idx].name,
b64_key);
if (print_len < 1 || print_len >= *buffer_len)
return PJ_ETOOSMALL;
*buffer_len = print_len;
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_size_t 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; 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 {
/* 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; i<m_rem->attr_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; j<cr_attr_count; ++j) {
if (tags[j] == tags[cr_attr_count]) {
DEACTIVATE_MEDIA(sdp_pool, m_loc);
return PJMEDIA_SRTP_ESDPDUPCRYPTOTAG;
}
}
if (matched_idx == -1) {
/* 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 */
/* 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; 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 > (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( (((pj_ssize_t)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