在freeswitch上解决被叫回183信令但不发RTP包的问题
问题描述：
在网络电话应用中，主叫收到IMS发送的183信令，但IMS不发送RTP包，导致主叫呼出后没有振铃声。
解决思路：
可以在客户端上解决，也可以在freeswitch服务器上解决
1、客户端上解决：收到183信令之后就播放本地铃声同时监测是否收到RTP数据，如果收到RTP数据就停止播放本地铃声；
2、服务器上解决：同样道理，如果被叫处于183振铃（early_media）状态，则监测是否收到RTP数据，如果没有收到则播放本地铃声，否则不再播放本地铃声。
以下记录为在服务器上解决的过程。因本人刚接触freeswitch，所以有些地方可能分析或描述不正确，请大家仅做参考，不要尽信。另外，本人使用的测试环境和通话过程与读者可能会有所不同，所以描述的现象和流程可能与读者也有不同。我使用的freeswitch版本为1.4.26。
解决过程：
因为大多数sip客户端程序作为被叫回复的都是180信令，因此我用两台freeswitch级联来模拟被叫回复183信令。具体拓扑结构为：主叫注册到fs1服务器，fs1与fs2级联，被叫注册到fs2服务器。
另外，因我做级联主要是为了模拟被叫回复183信令，所以在此约定除特别说明外，本文以后出现的被叫用词所指即为fs2。
-----------------------------------------【知识点】-----------------------------------------
1、从fs1上呼叫被叫拨号计划为（freeswitch默认外部端口为5080）：
2、fs2上的拨号计划要在conf/dialplan/public.xml中修改
3、freeswitch关于内部和外部的定义是：注册到本机的为内部，未注册在本机的为外部（包括级联freeswitch）；
最初的解决方案是：被叫回复183信令后，在fs1上监测被叫发过来的RTP包，如果没有收到RTP包就读入本地铃声伪造为收到的RTP包发给主叫。要实现这个方案必须要两步：第一是在fs2上屏蔽掉发送RTP包的代码，这样才能模拟被叫只发183信令而不发RTP包的情况；第二是在fs1上找到接收RTP包的地方，读入本地铃声伪造为收到的RTP包。
刚开始着手的时候在网上查到freeswtich有个rtp_timeout_sec是控制RTP包超时的，就是说如果freeswitch在设定的时间内收不到RTP包就结束通话。所以我通过查找这个参数相关的代码找到freeswitch收发RTP包的地方。
-----------------------------------------【知识点】-----------------------------------------
1、在配置文件conf/sip_profiles/internal.xml中设置的rtp_timeout_sec只对内部用户有效，在配置文件conf/sip_profiles/external.xml中设置的rtp_timeout_sec只对外部用户有效。并且这两个配置文件的设置是在freeswitch启动的时候读入的，因此如果修改配置之后，在控制台下的reloadxml命令是无法更新配置的，只能重新启动freeswitch；
2、拨号计划中设置rtp_timeout_sec只对内部主叫有效（对被叫是否有效未验证），并且会覆盖conf/sip_profiles/internal.xml中的设置；
3、控制台下的reloadxml命令只对拨号计划有效，对其他配置文件无效。
经过一番努力，终于找到freeswitch接收RTP数据是在src/switch_rtp.c文件的read_rtp_packet函数中，而发送RTP数据是在该文件的rtp_common_write函数中。至此，方案的第一步完成了，第二步完成了一半，接下来就该是怎么伪造RTP包的问题了。
因为RTP包的数据是经过语音编码的，所以首先要解决的就是语音编码问题，于是我通过在fs1的拨号计划中设置ringback来跟踪freeswitch在哪里读入本地文件并进行编码，然后怎么发送给主叫。拨号计划中的配置例子为：
-----------------------------------------【知识点】-----------------------------------------
1、freeswitch在拨号计划中不设置ringback，则回复的是180信令；
2、被叫回复180信令时：如果fs1的拨号计划不设置ringback，则fs1回复给主叫的是180信令；如果fs1的拨号计划设置了ringback参数，则fs1回复给主叫的是183信令，fs1会将本地铃声发送给主叫；
3、被叫回复183信令时：无论fs1的拨号计划是否设置ringback，fs1回复给主叫的都是183信令，并且主叫收到的铃声都是被叫传过来的铃声；如果被叫没有发送RTP包，即使fs1的拨号计划设置了ringback，fs1也不会将本地铃声发送给主叫。
第一步，先搞清楚需要发给主叫的数据是从哪里来的。在跟踪过程中，发现fs1和fs2不同的配置情况所执行的流程也不相同。
【第一种情况】fs1设置ringback，fs2不设置ringback时的流程为：
a、在switch_ivr_originate函数（src/switch_ivr_originate.c文件中）中调用setup_ringback函数执行初始化编码器、ringback结构体，打开本地铃声文件等操作；
b、在switch_ivr_originate函数（src/switch_ivr_originate.c文件中）中调用switch_core_file_read函数从本地文件读取一帧铃声数据；
c、在switch_ivr_originate函数（src/switch_ivr_originate.c文件中）中调用switch_core_session_write_frame，并传入从本地文件读取的铃声数据进行第二步。
【第二种情况】fs1设置ringback，fs2不设置ringback，并且fs1设置ring_ready、return_ring_ready为true时的流程为：
a、在switch_ivr_wait_for_answer函数（src/switch_ivr_originate.c文件中）中执行初始化编码器、ringback结构体，打开本地铃声文件等操作；
b、在switch_ivr_wait_for_answer函数（src/switch_ivr_originate.c文件中）中调用switch_core_file_read函数从本地文件读取一帧铃声数据。
c、在switch_ivr_wait_for_answer函数（src/switch_ivr_originate.c文件中）中调用switch_core_session_write_frame函数，并传入从本地文件读取的铃声数据进行第二步。
【第三种情况】fs2设置ringback时的流程为：
a、在audio_bridge_thread函数（src/switch_ivr_bridge.c文件中）中调用switch_core_session_read_frame函数（src/switch_core_io.c文件中）得到被叫发过来的铃声。获取的具体流程为：
（1）、在switch_core_session_read_frame函数中执行session->endpoint_interface->io_routines->read_frame，即调用sofia_read_frame函数（src/mod/endpoints/mod_sofia/mod_sofia.c文件中），因为session->endpoint_interface->io_routines->read_frame是一个函数指针，指向的就是该函数；
（2）、switch_core_media_read_frame函数（src/switch_core_media.c文件中）；
（3）、switch_rtp_zerocopy_read_frame函数（src/switch_rtp.c文件中）：从接收到的RTP包中取出铃声数据；
（4）、rtp_common_read函数（src/switch_rtp.c文件中）；
（5）、read_rtp_packet函数（src/switch_rtp.c文件中）；
（6）、switch_socket_recvfrom函数（src/switch_apr.c文件中）：接收被叫的RTP包。
b、在audio_bridge_thread函数（src/switch_ivr_originate.c文件中）中调用switch_core_session_write_frame函数，并传入被叫发过来的铃声进行第二步。
第二步，向主叫发送铃声，流程为：
a、switch_core_session_write_frame函数（src/switch_core_io.c文件中）：检测是否需要对铃声数据进行二次编码，如果需要则调用switch_core_codec_encode函数进行编码；
b、perform_write函数（src/switch_core_io.c文件中）：执行session->endpoint_interface->io_routines->write_frame，即调用sofia_write_frame函数（src/mod/endpoints/mod_sofia/mod_sofia.c文件中），因为session->endpoint_interface->io_routines->write_frame是一个函数指针，指向的就是该函数；
c、switch_core_media_write_frame函数（src/switch_core_media.c文件中）；
d、switch_rtp_write_frame函数（src/switch_rtp.c文件中）；
e、rtp_common_write函数（src/switch_rtp.c文件中）；
f、switch_socket_sendto函数（src/switch_apr.c文件中）：发送RTP包。
根据以上的跟踪和分析，我们知道只需要读取一帧铃声数据，然后调用switch_core_session_write_frame就可以很简单地完成编码和发送铃声，因此就没有必要在接收RTP包的地方，读入本地铃声再伪造为收到的RTP包，因为那样要增加读入铃声数据、编码和伪造RTP包三个步骤，明显更复杂。所以我们要对原方案进行优化。
很明显，我需要解决的问题属于上述的第三种情况（即fs2设置ringback时的流程），因此我只需要在audio_bridge_thread函数中从本地文件读取一帧铃声数据，然后传入switch_core_session_write_frame就能解决问题。
在以上的跟踪和分析中，我发现当被叫没有发送RTP包时，switch_core_session_read_frame函数得到的结果是一个SFF_CNG帧，即舒适噪声。所以具体的处理逻辑就是：如果被叫当前是183振铃状态（CCS_EARLY），并且得到的是SFF_CNG帧，那么就从本地文件读取一帧铃声数据，然后传入switch_core_session_write_frame。经测试问题解决。
最后需要说明的是：
1、ringback也可以是实时产生的单音铃声。这种情况下就不是从switch_core_file_read函数读取铃声数据了，而是调用switch_buffer_create_dynamic来实时产生铃声数据。拨号计划中的配置例子为：
2、我要解决的问题所处的环境中，被叫是IMS，所以被叫相对于freeswitch一定是外部用户。所以我在判断被叫当前是183振铃状态的时候加了一个条件：判断被叫是外部用户；
3、如果被叫是本机用户，并且回复183信令的时候，相关流程可能会与我上述的跟踪有所不同。我并未做测试。
另外，偶然发现一个问题：如果fs1和fs2都不设置ringback，并且fs1设置ring_ready、return_ring_ready为true，则fs1不会给主叫回180。至于原因还没去分析。
以下是我修改的全部代码，都在src/switch_ivr_bridge.c文件中。由宏_RINGBACK_包含的部分就是我增加的代码。
#ifdef _RINGBACK_
struct ringback {
switch_buffer_t *audio_buffer;
teletone_generation_session_t ts;
switch_file_handle_t fhb;
switch_file_handle_t *fh;
int silence;
uint8_t asis;
int channels;
void *mux_buf;
int mux_buflen;
};
typedef struct ringback ringback_t;
static int teletone_handler(teletone_generation_session_t *ts, teletone_tone_map_t *map)
{
ringback_t *tto = ts->user_data;
int wrote;
void *buf;
int buflen;
if (!tto) {
return -1;
}
wrote = teletone_mux_tones(ts, map);
if (tto->channels != 1) {
if (tto->mux_buflen < wrote * 2 * tto->channels) {
tto->mux_buflen = wrote * 2 * tto->channels;
tto->mux_buf = realloc(tto->mux_buf, tto->mux_buflen);
}
memcpy(tto->mux_buf, ts->buffer, wrote * 2);
switch_mux_channels((int16_t *) tto->mux_buf, wrote, 1, tto->channels);
buf = tto->mux_buf;
buflen = wrote * 2 * tto->channels;
} else {
buf = ts->buffer;
buflen = wrote * 2;
}
switch_buffer_write(tto->audio_buffer, buf, buflen);
return 0;
}
static void ringback_uninit(ringback_t ringback, switch_frame_t frame, switch_codec_t codec)
{
if (ringback.fh)
{
switch_core_file_close(ringback.fh);
ringback.fh = NULL;
}
else if (ringback.audio_buffer)
{
teletone_destroy_session(&ringback.ts);
switch_safe_free(ringback.mux_buf);
switch_buffer_destroy(&ringback.audio_buffer);
}
if (switch_core_codec_ready(&codec))
{
switch_core_codec_destroy(&codec);
}
switch_safe_free(frame.data);
}
#endif
static void *audio_bridge_thread(switch_thread_t *thread, void *obj)
{
switch_ivr_bridge_data_t *data = obj;
int stream_id = 0, pre_b = 0, ans_a = 0, ans_b = 0, originator = 0;
switch_input_callback_function_t input_callback;
switch_core_session_message_t msg = { 0 };
void *user_data;
switch_channel_t *chan_a, *chan_b;
switch_frame_t *read_frame;
switch_core_session_t *session_a, *session_b;
uint32_t read_frame_count = 0;
const char *app_name = NULL, *app_arg = NULL;
int inner_bridge = 0, exec_check = 0;
switch_codec_t silence_codec = { 0 };
switch_frame_t silence_frame = { 0 };
int16_t silence_data[SWITCH_RECOMMENDED_BUFFER_SIZE / 2] = { 0 };
const char *silence_var;
int silence_val = 0, bypass_media_after_bridge = 0;
const char *bridge_answer_timeout = NULL;
int bridge_filter_dtmf, answer_timeout, sent_update = 0;
time_t answer_limit = 0;
const char *exec_app = NULL;
const char *exec_data = NULL;
#ifdef SWITCH_VIDEO_IN_THREADS
switch_thread_t *vid_thread = NULL;
struct vid_helper vh = { 0 };
uint32_t vid_launch = 0;
#endif
#ifdef _RINGBACK_
switch_core_session_t *caller_session = NULL;
switch_channel_t *caller_channel = NULL;
const char *ringback_data = NULL;
switch_frame_t write_frame = { 0 };
switch_codec_t write_codec = { 0 };
switch_codec_t *read_codec;
uint8_t pass = 0;
ringback_t ringback = { 0 };
#endif
data->clean_exit = 0;
session_a = data->session;
if (!(session_b = switch_core_session_locate(data->b_uuid))) {
return NULL;
}
input_callback = data->input_callback;
user_data = data->session_data;
stream_id = data->stream_id;
chan_a = switch_core_session_get_channel(session_a);
chan_b = switch_core_session_get_channel(session_b);
if ((exec_app = switch_channel_get_variable(chan_a, "bridge_pre_execute_app"))) {
exec_data = switch_channel_get_variable(chan_a, "bridge_pre_execute_data");
}
bypass_media_after_bridge = switch_channel_test_flag(chan_a, CF_BYPASS_MEDIA_AFTER_BRIDGE);
switch_channel_clear_flag(chan_a, CF_BYPASS_MEDIA_AFTER_BRIDGE);
ans_a = switch_channel_test_flag(chan_a, CF_ANSWERED);
if ((originator = switch_channel_test_flag(chan_a, CF_BRIDGE_ORIGINATOR))) {
pre_b = switch_channel_test_flag(chan_a, CF_EARLY_MEDIA);
ans_b = switch_channel_test_flag(chan_b, CF_ANSWERED);
}
inner_bridge = switch_channel_test_flag(chan_a, CF_INNER_BRIDGE);
if (!switch_channel_test_flag(chan_a, CF_ANSWERED) && (bridge_answer_timeout = switch_channel_get_variable(chan_a, "bridge_answer_timeout"))) {
if ((answer_timeout = atoi(bridge_answer_timeout)) < 0) {
answer_timeout = 0;
} else {
answer_limit = switch_epoch_time_now(NULL) + answer_timeout;
}
}
switch_channel_clear_flag(chan_a, CF_INTERCEPT);
switch_channel_clear_flag(chan_a, CF_INTERCEPTED);
switch_channel_set_flag(chan_a, CF_BRIDGED);
switch_channel_wait_for_flag(chan_b, CF_BRIDGED, SWITCH_TRUE, 10000, chan_a);
if (!switch_channel_test_flag(chan_b, CF_BRIDGED)) {
if (!(switch_channel_test_flag(chan_b, CF_TRANSFER) || switch_channel_test_flag(chan_b, CF_REDIRECT)
|| switch_channel_get_state(chan_b) == CS_RESET)) {
switch_channel_hangup(chan_b, SWITCH_CAUSE_DESTINATION_OUT_OF_ORDER);
}
goto end_of_bridge_loop;
}
if (bypass_media_after_bridge) {
const char *source_a = switch_channel_get_variable(chan_a, "source");
const char *source_b = switch_channel_get_variable(chan_b, "source");
if (!source_a) source_a = "";
if (!source_b) source_b = "";
if (switch_stristr("loopback", source_a) || switch_stristr("loopback", source_b)) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_WARNING, "Cannot bypass media while bridged to a loopback address.\n");
bypass_media_after_bridge = 0;
}
}
if ((silence_var = switch_channel_get_variable(chan_a, "bridge_generate_comfort_noise"))) {
switch_codec_implementation_t read_impl = { 0 };
switch_core_session_get_read_impl(session_a, &read_impl);
if (!switch_channel_media_up(chan_a)) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_ERROR, "Channel has no media!\n");
goto end_of_bridge_loop;
}
if (switch_true(silence_var)) {
silence_val = 1400;
} else {
if ((silence_val = atoi(silence_var)) < -1) {
silence_val = 0;
}
}
if (silence_val) {
if (switch_core_codec_init(&silence_codec,
"L16",
NULL,
read_impl.actual_samples_per_second,
read_impl.microseconds_per_packet / 1000,
1,
SWITCH_CODEC_FLAG_ENCODE | SWITCH_CODEC_FLAG_DECODE,
NULL, switch_core_session_get_pool(session_a)) != SWITCH_STATUS_SUCCESS) {
silence_val = 0;
} else {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "Setup generated silence from %s to %s at %d\n", switch_channel_get_name(chan_a),
switch_channel_get_name(chan_b), silence_val);
silence_frame.codec = &silence_codec;
silence_frame.data = silence_data;
silence_frame.buflen = sizeof(silence_data);
silence_frame.datalen = read_impl.decoded_bytes_per_packet;
silence_frame.samples = silence_frame.datalen / sizeof(int16_t);
}
}
}
bridge_filter_dtmf = switch_true(switch_channel_get_variable(chan_a, "bridge_filter_dtmf"));
#ifdef _RINGBACK_
if (switch_channel_direction(chan_a) == SWITCH_CALL_DIRECTION_OUTBOUND)
{
caller_channel = chan_b;
caller_session = session_b;
ringback_data = switch_channel_get_variable(caller_channel, "ringback");
if (ringback_data != NULL)
{
switch_zmalloc(write_frame.data, SWITCH_RECOMMENDED_BUFFER_SIZE);
write_frame.buflen = SWITCH_RECOMMENDED_BUFFER_SIZE;
read_codec = switch_core_session_get_read_codec(caller_session);
}
if (read_codec && ringback_data)
{
if (switch_is_file_path(ringback_data))
{
if (!(strrchr(ringback_data, '.') || strstr(ringback_data, SWITCH_URL_SEPARATOR)))
{
ringback.asis++;
}
}
if (!ringback.asis)
{
if ((pass = (uint8_t) switch_test_flag(read_codec, SWITCH_CODEC_FLAG_PASSTHROUGH)))
{
ringback_data = NULL;
}
else
{
if (switch_core_codec_init(&write_codec,
"L16",
NULL,
read_codec->implementation->actual_samples_per_second,
read_codec->implementation->microseconds_per_packet / 1000,
read_codec->implementation->number_of_channels, SWITCH_CODEC_FLAG_ENCODE | SWITCH_CODEC_FLAG_DECODE, NULL,
switch_core_session_get_pool(caller_session)) != SWITCH_STATUS_SUCCESS)
{
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(caller_session), SWITCH_LOG_ERROR, "Codec Error!\n");
if (caller_channel)
{
switch_channel_hangup(caller_channel, SWITCH_CAUSE_BEARERCAPABILITY_NOTIMPL);
}
read_codec = NULL;
ringback_uninit(ringback, write_frame, write_codec);
ringback_data = NULL;
}
else
{
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(caller_session), SWITCH_LOG_DEBUG,
"Raw Codec Activation Success L16@%uhz 1 channel %dms\n",
read_codec->implementation->actual_samples_per_second, read_codec->implementation->microseconds_per_packet / 1000);
write_frame.codec = &write_codec;
write_frame.datalen = read_codec->implementation->decoded_bytes_per_packet;
write_frame.samples = write_frame.datalen / 2;
memset(write_frame.data, 255, write_frame.datalen);
}
}
}
if (switch_channel_test_flag(caller_channel, CF_DISABLE_RINGBACK))
{
ringback_data = NULL;
}
if (ringback_data)
{
char *tmp_data = NULL;
if (switch_is_file_path(ringback_data))
{
char *ext;
if (ringback.asis) {
write_frame.codec = read_codec;
ext = read_codec->implementation->iananame;
tmp_data = switch_mprintf("%s.%s", ringback_data, ext);
ringback_data = tmp_data;
}
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(caller_session), SWITCH_LOG_DEBUG, "Play Ringback File [%s]\n", ringback_data);
ringback.fhb.channels = read_codec->implementation->number_of_channels;
ringback.fhb.samplerate = read_codec->implementation->actual_samples_per_second;
if (switch_core_file_open(&ringback.fhb,
ringback_data,
read_codec->implementation->number_of_channels,
read_codec->implementation->actual_samples_per_second,
SWITCH_FILE_FLAG_READ | SWITCH_FILE_DATA_SHORT, NULL) != SWITCH_STATUS_SUCCESS)
{
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(caller_session), SWITCH_LOG_ERROR, "Error Playing File\n");
switch_safe_free(tmp_data);
ringback_uninit(ringback, write_frame, write_codec);
ringback_data = NULL;
}
else
{
ringback.fh = &ringback.fhb;
}
}
else
{
if (!strncasecmp(ringback_data, "silence", 7))
{
ringback_data = NULL;
}
else
{
switch_buffer_create_dynamic(&ringback.audio_buffer, 512, 1024, 0);
switch_buffer_set_loops(ringback.audio_buffer, -1);
teletone_init_session(&ringback.ts, 0, teletone_handler, &ringback);
ringback.ts.rate = read_codec->implementation->actual_samples_per_second;
ringback.channels = read_codec->implementation->number_of_channels;
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(caller_session), SWITCH_LOG_DEBUG, "Play Ringback Tone [%s]\n", ringback_data);
if (teletone_run(&ringback.ts, ringback_data))
{
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(caller_session), SWITCH_LOG_ERROR, "Error Playing Tone\n");
teletone_destroy_session(&ringback.ts);
switch_buffer_destroy(&ringback.audio_buffer);
ringback_data = NULL;
}
}
}
switch_safe_free(tmp_data);
}
}
}
#endif
for (;;) {
switch_channel_state_t b_state;
switch_status_t status;
switch_event_t *event;
if (switch_channel_test_flag(chan_a, CF_TRANSFER)) {
data->clean_exit = 1;
}
if (data->clean_exit || switch_channel_test_flag(chan_b, CF_TRANSFER)) {
switch_channel_clear_flag(chan_a, CF_HOLD);
switch_channel_clear_flag(chan_a, CF_SUSPEND);
goto end_of_bridge_loop;
}
if (!switch_channel_test_flag(chan_b, CF_BRIDGED)) {
goto end_of_bridge_loop;
}
if (!switch_channel_ready(chan_a)) {
if (switch_channel_up(chan_a)) {
data->clean_exit = 1;
}
goto end_of_bridge_loop;
}
if ((b_state = switch_channel_down_nosig(chan_b))) {
goto end_of_bridge_loop;
}
if (switch_channel_test_flag(chan_a, CF_HOLD_ON_BRIDGE)) {
switch_core_session_message_t hmsg = { 0 };
switch_channel_clear_flag(chan_a, CF_HOLD_ON_BRIDGE);
hmsg.message_id = SWITCH_MESSAGE_INDICATE_HOLD;
hmsg.from = __FILE__;
hmsg.numeric_arg = 1;
switch_core_session_receive_message(session_a, &hmsg);
}
if (read_frame_count > DEFAULT_LEAD_FRAMES && switch_channel_media_ack(chan_a) && switch_core_session_private_event_count(session_a)) {
switch_channel_set_flag(chan_b, CF_SUSPEND);
msg.numeric_arg = 42;
msg.string_arg = data->b_uuid;
msg.message_id = SWITCH_MESSAGE_INDICATE_UNBRIDGE;
msg.from = __FILE__;
switch_core_session_receive_message(session_a, &msg);
switch_ivr_parse_next_event(session_a);
msg.message_id = SWITCH_MESSAGE_INDICATE_BRIDGE;
switch_core_session_receive_message(session_a, &msg);
switch_channel_clear_flag(chan_b, CF_SUSPEND);
switch_core_session_kill_channel(session_b, SWITCH_SIG_BREAK);
}
switch_ivr_parse_all_messages(session_a);
if (!inner_bridge && (switch_channel_test_flag(chan_a, CF_SUSPEND) || switch_channel_test_flag(chan_b, CF_SUSPEND))) {
status = switch_core_session_read_frame(session_a, &read_frame, SWITCH_IO_FLAG_NONE, stream_id);
if (!SWITCH_READ_ACCEPTABLE(status)) {
goto end_of_bridge_loop;
}
continue;
}
#ifdef SWITCH_VIDEO_IN_THREADS
if (switch_channel_test_flag(chan_a, CF_VIDEO) && switch_channel_test_flag(chan_b, CF_VIDEO) && !vid_launch) {
vid_launch++;
vh.session_a = session_a;
vh.session_b = session_b;
vid_thread = launch_video(&vh);
}
#endif
if (read_frame_count >= DEFAULT_LEAD_FRAMES && switch_channel_media_ack(chan_a)) {
if (!exec_check) {
switch_channel_execute_on(chan_a, SWITCH_CHANNEL_EXECUTE_ON_PRE_BRIDGE_VARIABLE);
if (!inner_bridge) {
switch_channel_api_on(chan_a, SWITCH_API_BRIDGE_START_VARIABLE);
}
exec_check = 1;
}
if (exec_app) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "%s Bridge execute app %s(%s)\n",
switch_channel_get_name(chan_a), exec_app, exec_data);
switch_core_session_execute_application_async(session_a, exec_app, exec_data);
exec_app = exec_data = NULL;
}
if ((bypass_media_after_bridge || switch_channel_test_flag(chan_b, CF_BYPASS_MEDIA_AFTER_BRIDGE)) && switch_channel_test_flag(chan_a, CF_ANSWERED)
&& switch_channel_test_flag(chan_b, CF_ANSWERED)) {
switch_ivr_nomedia(switch_core_session_get_uuid(session_a), SMF_REBRIDGE);
bypass_media_after_bridge = 0;
switch_channel_clear_flag(chan_b, CF_BYPASS_MEDIA_AFTER_BRIDGE);
goto end_of_bridge_loop;
}
}
/* if 1 channel has DTMF pass it to the other */
while (switch_channel_has_dtmf(chan_a)) {
switch_dtmf_t dtmf = { 0, 0 };
if (switch_channel_dequeue_dtmf(chan_a, &dtmf) == SWITCH_STATUS_SUCCESS) {
int send_dtmf = 1;
if (input_callback) {
switch_status_t cb_status = input_callback(session_a, (void *) &dtmf, SWITCH_INPUT_TYPE_DTMF, user_data, 0);
if (cb_status == SWITCH_STATUS_IGNORE) {
send_dtmf = 0;
} else if (cb_status != SWITCH_STATUS_SUCCESS) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "%s ended call via DTMF\n", switch_channel_get_name(chan_a));
switch_core_session_kill_channel(session_b, SWITCH_SIG_BREAK);
goto end_of_bridge_loop;
}
}
if (bridge_filter_dtmf) {
send_dtmf = 0;
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "Dropping filtered DTMF received on %s\n", switch_channel_get_name(chan_a));
}
if (send_dtmf) {
switch_core_session_send_dtmf(session_b, &dtmf);
switch_core_session_kill_channel(session_b, SWITCH_SIG_BREAK);
}
}
}
if (switch_core_session_dequeue_event(session_a, &event, SWITCH_FALSE) == SWITCH_STATUS_SUCCESS) {
if (input_callback) {
status = input_callback(session_a, event, SWITCH_INPUT_TYPE_EVENT, user_data, 0);
}
if ((event->event_id != SWITCH_EVENT_COMMAND && event->event_id != SWITCH_EVENT_MESSAGE)
|| switch_core_session_receive_event(session_b, &event) != SWITCH_STATUS_SUCCESS) {
switch_event_destroy(&event);
}
}
if (!switch_channel_test_flag(chan_a, CF_ANSWERED) && answer_limit && switch_epoch_time_now(NULL) > answer_limit) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "Answer timeout hit on %s.\n", switch_channel_get_name(chan_a));
if (switch_true(switch_channel_get_variable_dup(chan_a, "continue_on_answer_timeout", SWITCH_FALSE, -1))) {
data->clean_exit = 1;
goto end_of_bridge_loop;
} else {
switch_channel_hangup(chan_a, SWITCH_CAUSE_ALLOTTED_TIMEOUT);
}
}
if (!switch_channel_test_flag(chan_a, CF_ANSWERED)) {
if (originator) {
if (!ans_b && switch_channel_test_flag(chan_b, CF_ANSWERED)) {
switch_channel_pass_callee_id(chan_b, chan_a);
if (switch_channel_answer(chan_a) != SWITCH_STATUS_SUCCESS) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "%s Media Establishment Failed.\n", switch_channel_get_name(chan_a));
goto end_of_bridge_loop;
}
ans_a = 1;
} else if (!pre_b && switch_channel_test_flag(chan_b, CF_EARLY_MEDIA)) {
if (switch_channel_pre_answer(chan_a) != SWITCH_STATUS_SUCCESS) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "%s Media Establishment Failed.\n", switch_channel_get_name(chan_a));
goto end_of_bridge_loop;
}
pre_b = 1;
}
if (!pre_b) {
switch_yield(10000);
continue;
}
} else {
ans_a = switch_channel_test_flag(chan_b, CF_ANSWERED);
}
}
if (ans_a != ans_b) {
switch_channel_t *un = ans_a ? chan_b : chan_a;
switch_channel_t *a = un == chan_b ? chan_a : chan_b;
if (switch_channel_direction(un) == SWITCH_CALL_DIRECTION_INBOUND) {
if (switch_channel_direction(a) == SWITCH_CALL_DIRECTION_OUTBOUND || (un == chan_a && !originator)) {
switch_channel_pass_callee_id(a, un);
}
if (switch_channel_answer(un) != SWITCH_STATUS_SUCCESS) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "%s Media Establishment Failed.\n", switch_channel_get_name(un));
goto end_of_bridge_loop;
}
if (ans_a) {
ans_b = 1;
} else {
ans_a = 1;
}
}
}
if (originator && !ans_b) ans_b = switch_channel_test_flag(chan_b, CF_ANSWERED);
if (originator && !sent_update && ans_a && ans_b && switch_channel_media_ack(chan_a) && switch_channel_media_ack(chan_b)) {
switch_ivr_bridge_display(session_a, session_b);
sent_update = 1;
}
#ifndef SWITCH_VIDEO_IN_THREADS
if (switch_channel_test_flag(chan_a, CF_VIDEO) && switch_channel_test_flag(chan_b, CF_VIDEO)) {
/* read video from 1 channel and write it to the other */
status = switch_core_session_read_video_frame(session_a, &read_frame, SWITCH_IO_FLAG_NONE, 0);
if (!SWITCH_READ_ACCEPTABLE(status)) {
goto end_of_bridge_loop;
}
switch_core_session_write_video_frame(session_b, read_frame, SWITCH_IO_FLAG_NONE, 0);
}
#endif
/* read audio from 1 channel and write it to the other */
status = switch_core_session_read_frame(session_a, &read_frame, SWITCH_IO_FLAG_NONE, stream_id);
if (SWITCH_READ_ACCEPTABLE(status)) {
read_frame_count++;
#ifdef _RINGBACK_
if ((switch_channel_direction(chan_a) == SWITCH_CALL_DIRECTION_OUTBOUND) && (switch_channel_get_callstate(chan_a) == CCS_EARLY))
{
//在被叫183振铃状态下，如果没有收到被叫的rtp数据则播放本地回铃，如果已经收到过被叫rtp数据则不再播放本地回铃
if (switch_test_flag(read_frame, SFF_CNG))
{
if (ringback_data != NULL)
{
switch_bool_t ringback_status = SWITCH_TRUE;
if (ringback.fh)
{
switch_size_t mlen, olen;
unsigned int pos = 0;
if (ringback.asis)
{
mlen = write_frame.codec->implementation->encoded_bytes_per_packet;
}
else
{
mlen = write_frame.codec->implementation->samples_per_packet;
}
olen = mlen;
//if (ringback.fh->resampler && ringback.fh->resampler->rfactor > 1) {
//olen = (switch_size_t) (olen * ringback.fh->resampler->rfactor);
//}
switch_core_file_read(ringback.fh, write_frame.data, &olen);
if (olen == 0)
{
olen = mlen;
ringback.fh->speed = 0;
switch_core_file_seek(ringback.fh, &pos, 0, SEEK_SET);
switch_core_file_read(ringback.fh, write_frame.data, &olen);
if (olen == 0)
{
switch_log_printf(SWITCH_CHANNEL_CHANNEL_LOG(caller_channel), SWITCH_LOG_ERROR,
"Failure to read or re-read after seeking to beginning on file [%s]\n", ringback.fh->file_path);
ringback_status = SWITCH_FALSE;
}
}
write_frame.datalen = (uint32_t) (ringback.asis ? olen : olen * 2 * ringback.fh->channels);
}
else if (ringback.audio_buffer)
{
if ((write_frame.datalen = (uint32_t) switch_buffer_read_loop(ringback.audio_buffer,
write_frame.data,
write_frame.codec->implementation->decoded_bytes_per_packet)) <= 0)
{
ringback_status = SWITCH_FALSE;
}
}
else
{
ringback_status = SWITCH_FALSE;
}
if ((ringback.fh || ringback.audio_buffer) && write_frame.codec && write_frame.datalen && (ringback_status == SWITCH_TRUE))
{
read_frame = &write_frame;
switch_clear_flag(read_frame, SFF_CNG);
}
}
}
else
{
if (ringback_data != NULL)
{
//已经收到过被叫的rtp数据，不再播放本地回铃
ringback_uninit(ringback, write_frame, write_codec);
ringback_data = NULL;
}
}
}
#endif
if (switch_test_flag(read_frame, SFF_CNG)) {
if (silence_val) {
switch_generate_sln_silence((int16_t *) silence_frame.data, silence_frame.samples,
read_frame->codec->implementation->number_of_channels, silence_val);
read_frame = &silence_frame;
} else if (!switch_channel_test_flag(chan_b, CF_ACCEPT_CNG)) {
continue;
}
}
if (switch_channel_test_flag(chan_a, CF_BRIDGE_NOWRITE)) {
continue;
}
if (status != SWITCH_STATUS_BREAK && !switch_channel_test_flag(chan_a, CF_HOLD)) {
if (switch_core_session_write_frame(session_b, read_frame, SWITCH_IO_FLAG_NONE, stream_id) != SWITCH_STATUS_SUCCESS) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG,
"%s ending bridge by request from write function\n", switch_channel_get_name(chan_b));
goto end_of_bridge_loop;
}
}
} else {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "%s ending bridge by request from read function\n", switch_channel_get_name(chan_a));
goto end_of_bridge_loop;
}
}
end_of_bridge_loop:
#ifdef SWITCH_VIDEO_IN_THREADS
if (vid_thread) {
vh.up = -1;
switch_channel_set_flag(chan_a, CF_NOT_READY);
//switch_channel_set_flag(chan_b, CF_NOT_READY);
switch_core_session_kill_channel(session_a, SWITCH_SIG_BREAK);
switch_core_session_kill_channel(session_b, SWITCH_SIG_BREAK);
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "Ending video thread.\n");
}
#endif
#ifdef _RINGBACK_
if (ringback_data != NULL)
{
ringback_uninit(ringback, write_frame, write_codec);
}
#endif
if (silence_val) {
switch_core_codec_destroy(&silence_codec);
}
switch_channel_execute_on(chan_a, SWITCH_CHANNEL_EXECUTE_ON_POST_BRIDGE_VARIABLE);
if (!inner_bridge) {
switch_channel_api_on(chan_a, SWITCH_API_BRIDGE_END_VARIABLE);
}
if (!inner_bridge && switch_channel_up_nosig(chan_a)) {
if ((app_name = switch_channel_get_variable(chan_a, SWITCH_EXEC_AFTER_BRIDGE_APP_VARIABLE))) {
switch_caller_extension_t *extension = NULL;
if ((extension = switch_caller_extension_new(session_a, app_name, app_name)) == 0) {
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_CRIT, "memory error!\n");
goto end;
}
app_arg = switch_channel_get_variable(chan_a, SWITCH_EXEC_AFTER_BRIDGE_ARG_VARIABLE);
switch_caller_extension_add_application(session_a, extension, (char *) app_name, app_arg);
switch_channel_set_caller_extension(chan_a, extension);
if (switch_channel_get_state(chan_a) == CS_EXECUTE) {
switch_channel_set_flag(chan_a, CF_RESET);
} else {
switch_channel_set_state(chan_a, CS_EXECUTE);
}
}
}
end:
#ifdef SWITCH_VIDEO_IN_THREADS
if (vid_thread) {
switch_status_t st;
if (vh.up == 1) {
vh.up = -1;
}
switch_channel_set_flag(chan_a, CF_VIDEO_BREAK);
switch_channel_set_flag(chan_b, CF_VIDEO_BREAK);
switch_core_session_kill_channel(session_a, SWITCH_SIG_BREAK);
switch_core_session_kill_channel(session_b, SWITCH_SIG_BREAK);
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "Ending video thread.\n");
switch_thread_join(&st, vid_thread);
switch_channel_clear_flag(chan_a, CF_NOT_READY);
switch_channel_clear_flag(chan_b, CF_NOT_READY);
}
#endif
switch_core_session_reset(session_a, SWITCH_TRUE, SWITCH_TRUE);
switch_channel_set_variable(chan_a, SWITCH_BRIDGE_VARIABLE, NULL);
switch_log_printf(SWITCH_CHANNEL_SESSION_LOG(session_a), SWITCH_LOG_DEBUG, "BRIDGE THREAD DONE [%s]\n", switch_channel_get_name(chan_a));
switch_channel_clear_flag(chan_a, CF_BRIDGED);
if (switch_channel_test_flag(chan_a, CF_LEG_HOLDING) || switch_channel_test_flag(chan_a, CF_HANGUP_HELD)) {
if (switch_channel_ready(chan_b) && switch_channel_get_state(chan_b) != CS_PARK && !data->other_leg_data->clean_exit) {
const char *ext = switch_channel_get_variable(chan_a, "hold_hangup_xfer_exten");
switch_channel_stop_broadcast(chan_b);
if (zstr(ext)) {
switch_call_cause_t cause = switch_channel_get_cause(chan_b);
if (cause == SWITCH_CAUSE_NONE) {
cause = SWITCH_CAUSE_NORMAL_CLEARING;
}
switch_channel_hangup(chan_b, cause);
} else {
switch_channel_set_variable(chan_b, SWITCH_TRANSFER_AFTER_BRIDGE_VARIABLE, ext);
}
}
if (switch_channel_test_flag(chan_a, CF_LEG_HOLDING)) {
switch_channel_mark_hold(chan_a, SWITCH_FALSE);
}
}
if (switch_channel_test_flag(chan_a, CF_INTERCEPTED)) {
switch_channel_set_flag(chan_b, CF_INTERCEPT);
}
switch_core_session_kill_channel(session_b, SWITCH_SIG_BREAK);
data->done = 1;
switch_core_session_rwunlock(session_b);
return NULL;
}