熟悉的过程:
switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_INFO, "Activate Eventing Engine.\n");
将日志输出到文件,并SetConsoleTextAttribute来设置输出log的颜色,便于区分
fs提供多种方式来输出日志文件
switch_log_printf(SWITCH_CHANNEL_LOG , SWITCH_LOG_CONSOLE, "Successfully
Loaded [%s]\n", module_interface-> module_name);
switch_log_printf(SWITCH_CHANNEL_LOG , SWITCH_LOG_DEBUG, "Successfully
Loaded [%s]\n", module-> filename);
switch_log_printf(SWITCH_CHANNEL_LOG , SWITCH_LOG_DEBUG, "Call switch_core_media_read_frame() Function!\n");
说明一下switch_log_printf的使用方法
SetConsoleTextAttribute设置输出文本的颜
freeswitch在启动时的加载过程
switch_event_init 初始化事件
switch_nat.c进行nat检测
switch_core_sqldb.c 数据库的初始化和检测
网络相关的设置
switch_loadable_module.c加载需要的模块(比如:编解码模块,API Function )
加载模块Timer
switch_loadable_module.c:1401 Successfully Loaded [CORE_SOFTTIMER_MODULE]
switch_loadable_module.c:238 Adding Timer ‘soft‘
加载Logger中的Console和logFile文件
switch_loadable_module.c:1401 Successfully Loaded [mod_console]
switch_loadable_module.c:1401 Successfully Loaded [mod_logfile]
加载通信方式(以Event_Socket方式通信)
switch_loadable_module.c:1401 Successfully Loaded [mod_event_socket]
初始化消息线程
mod_sofia.c:5176 Starting initial message thread
2015-04-14 10:12:04.535099 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_sofia]
加载对应配置文件后,加载sofia模块,成功.
需要介绍一下sofia模块的作用
加载Endpoint模块
2015-04-14 10:12:04.535151 [NOTICE] switch_loadable_module.c:147 Adding Endpoint ‘sofia‘
2015-04-14 10:12:04.535240 [NOTICE] switch_loadable_module.c:147 Adding Endpoint ‘rtp‘
介绍Endpoint**
Endpoint是什么冬冬?
Endpoint是freeswitch的终结的地方,我理解的是和外界通信的界限.出了Endpoint的地方就脱离了freeswitch的控制了.
正在开启数据库线程
2015-04-14 10:12:03.027548 [INFO] switch_core_sqldb.c:1449 sofia:internal-ipv6 Starting SQL thread.
2015-04-14 10:12:03.030162 [INFO] switch_core_sqldb.c:1449 sofia:external Starting SQL thread.
2015-04-14 10:12:03.031207 [NOTICE] sofia_reg.c:3165 Added gateway ‘example.com‘ to profile ‘external‘
2015-04-14 10:12:03.032423 [INFO] switch_core_sqldb.c:1449 sofia:internal Starting SQL thread.
加载命令行模块
switch_loadable_module.c:1401 Successfully Loaded [mod_commands]
加载mod_conference模块
2015-04-14 10:12:04.594931 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_conference]
2015-04-14 10:12:04.594955 [NOTICE] switch_loadable_module.c:259 Adding Application ‘conference‘
2015-04-14 10:12:04.595006 [NOTICE] switch_loadable_module.c:259 Adding Application ‘conference_set_auto_outcall‘
2015-04-14 10:12:04.595050 [NOTICE] switch_loadable_module.c:305 Adding API Function ‘conference‘
2015-04-14 10:12:04.595079 [NOTICE] switch_loadable_module.c:417 Adding Chat interface ‘conf‘
加载DB数据库
2015-04-14 10:12:04.627689 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_db]
2015-04-14 10:12:04.627736 [NOTICE] switch_loadable_module.c:259 Adding Application ‘db‘
2015-04-14 10:12:04.627779 [NOTICE] switch_loadable_module.c:259 Adding Application ‘group‘
2015-04-14 10:12:04.627864 [NOTICE] switch_loadable_module.c:305 Adding API Function ‘db‘
2015-04-14 10:12:04.627894 [NOTICE] switch_loadable_module.c:305 Adding API Function ‘group‘
2015-04-14 10:12:04.627920 [NOTICE] switch_loadable_module.c:490 Adding Limit interface ‘db‘
2015-04-14 10:12:05.208136 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_fifo]
2015-04-14 10:12:05.213144 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_hash]
定位到源文件
相当于添加一个api接口hash到系统核心,当有事件发生时,则调用hash_remote_function()函数
加载语音信箱模块
2015-04-14 10:12:05.252991 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_voicemail]
2015-04-14 10:12:05.256017 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_esf]
2015-04-14 10:12:05.257130 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_fsv]
2015-04-14 10:12:05.258452 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_cluechoo]
2015-04-14 10:12:05.261723 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_valet_parking]
2015-04-14 10:12:05.263445 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_httapi]
2015-04-14 10:12:05.263464 [NOTICE] switch_loadable_module.c:259 Adding Application ‘httapi‘
2015-04-14 10:12:05.263529 [NOTICE] switch_loadable_module.c:305 Adding API Function ‘httapi‘
2015-04-14 10:12:05.263576 [NOTICE] switch_loadable_module.c:332 Adding File Format ‘http‘
2015-04-14 10:12:05.263618 [NOTICE] switch_loadable_module.c:332 Adding File Format ‘https‘
加载拨号计划(比如SIP和asterisk)
2015-04-14 10:12:05.268003 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_dialplan_xml]
2015-04-14 10:12:05.268066 [NOTICE] switch_loadable_module.c:217 Adding Dialplan ‘XML‘
2015-04-14 10:12:05.268799 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_dialplan_asterisk]
2015-04-14 10:12:05.268824 [NOTICE] switch_loadable_module.c:147 Adding Endpoint ‘SIP‘
2015-04-14 10:12:05.268902 [NOTICE] switch_loadable_module.c:147 Adding Endpoint ‘IAX2‘
2015-04-14 10:12:05.268953 [NOTICE] switch_loadable_module.c:217 Adding Dialplan ‘asterisk‘
2015-04-14 10:12:05.268996 [NOTICE] switch_loadable_module.c:259 Adding Application ‘Dial‘
2015-04-14 10:12:05.269040 [NOTICE] switch_loadable_module.c:259 Adding Application ‘Goto‘
2015-04-14 10:12:05.269084 [NOTICE] switch_loadable_module.c:259 Adding Application ‘AvoidingDeadlock‘
2015-04-14 10:12:05.344929 [CONSOLE] switch_loadable_module.c:1401 Successfully Loaded [mod_spandsp]
开源项目组织结构
核心: 核心代码都经过精心的编码和严格的测试，最大限度地保持了系统整体的稳定。外围模块只能通过 API 调用核心的功能。 模块是可以动态加载（以及卸载）的，在实际应用中可以只加载用到的模块。外围模块通过核心提供的 Public API 与核心进行通信，而核心则通过回调机制执行外围模块中的代码。 FreeSWITCH 使用线程模型来处理并发请求，每个连接都在单独的线程中进行处理。
主要核心内容:
1/项目模块的初始化和加载过程
mofia.c是个核心的源文件,项目源代码整体上采用的是核心+模块的方式
switch_loadable_module_load_module_ex()函数调用
switch_loadable_module_load_file将共享库加载到进程的地址空间中
switch_loadable_module_process将共享库提供的各个接口,加入到全局的哈希表中
2/读取(写)音频视频流的过程,以读为例mod_sofia.c
系统在加载mod_sofia模块的时候,会注册一些回调函数给核心core
注册的回调函数有
switch_io_routines_t sofia_io_routines =
{
/*.outgoing_channel */ sofia_outgoing_channel ,
/*.read_frame */ sofia_read_frame ,
/*.write_frame */ sofia_write_frame ,
/*.kill_channel */ sofia_kill_channel ,
/*.send_dtmf */ sofia_send_dtmf ,
/*.receive_message */ sofia_receive_message ,
/*.receive_event */ sofia_receive_event ,
/*.state_change */ NULL ,
/*.read_video_frame */ sofia_read_video_frame ,
/*.write_video_frame */ sofia_write_video_frame ,
/*.state_run*/ NULL ,
/*.get_jb*/ sofia_get_jb
};
当发生指定的fs事件时,核心core就会调用相应的回调函数.
fs在读取音频数据和视频数据的时候是分离的,过程如下:
第一步:sofia_read_frame()函数中,处理音频数据,继续调用switch_core_media_read_frame
static switch_status_t sofia_read_frame( switch_core_session_t *session , switch_frame_t **frame, switch_io_flag_t flags, int stream_id )
{
private_object_t *tech_pvt = switch_core_session_get_private( session);
switch_channel_t *channel = switch_core_session_get_channel( session);
uint32_t sanity =
1000;
switch_status_t status = SWITCH_STATUS_FALSE;
switch_assert(tech_pvt != NULL);
//监测sofia模块运行,如果失败则挂断并返回错误
if (!sofia_test_pflag (tech_pvt-> profile, PFLAG_RUNNING ))
{
switch_channel_hangup(tech_pvt ->channel, SWITCH_CAUSE_NORMAL_CLEARING );
return SWITCH_STATUS_FALSE ;
}
//监测TFLAG_HUP标志
if (sofia_test_flag (tech_pvt, TFLAG_HUP))
{
return SWITCH_STATUS_FALSE ;
}
while (!(switch_core_media_ready (tech_pvt-> session, SWITCH_MEDIA_TYPE_AUDIO)
&& !switch_channel_test_flag (channel, CF_REQ_MEDIA)))
{
switch_ivr_parse_all_messages(tech_pvt ->session);
if (--sanity && switch_channel_up( channel))
{
switch_yield(10000);
} else {
switch_channel_hangup(tech_pvt ->channel, SWITCH_CAUSE_RECOVERY_ON_TIMER_EXPIRE );
return SWITCH_STATUS_GENERR ;
}
}
//加锁,读取桢数据
sofia_set_flag_locked(tech_pvt , TFLAG_READING);
//在读取过程中,本端或者对端挂断
if (sofia_test_flag (tech_pvt, TFLAG_HUP)
|| sofia_test_flag (tech_pvt, TFLAG_BYE))
{
return SWITCH_STATUS_FALSE ;
}
//调用switch_core_media.c中的函数来读取桢数据
status = switch_core_media_read_frame (session, frame, flags , stream_id, SWITCH_MEDIA_TYPE_AUDIO);
//读取完毕,解锁
sofia_clear_flag_locked(tech_pvt , TFLAG_READING);
return status ;
}
第二步:在switch_core_media_read_frame函数 中
//获取媒体的类型
//SWITCH_MEDIA_TYPE_AUDIO为音频,SWITCH_MEDIA_TYPE_VIDEO为视频数据
engine = &smh ->engines[ type];
//check the read_codec is ready,if no,return SWITCH_STATUS_FALSE
//监测用于读的解码库是否就绪
if (!engine ->read_codec. implementation ||
!switch_core_codec_ready(&engine ->read_codec))
{
return SWITCH_STATUS_FALSE ;
}
然后继续调用switch_rtp_zerocopy_read_frame()函数从rtp中读取桢数据(主要读取桢数据的地方,两个客户端通信主要是RTP协议)
调用并读取桢数据成功则创建事件,并对事件各参数赋值
/* Fast PASS! if proxy mode !*/
if (switch_test_flag ((&engine-> read_frame), SFF_PROXY_PACKET ))
{
* frame =
&engine ->read_frame;
return SWITCH_STATUS_SUCCESS ;
}
如果是代理模式,则读取桢数据后直接返回,不做任何处理,只起到代理的功能.
第三步:在switch_rtp_zerocopy_read_frame()函数中调用rtp_common_read()函数
将读取到的数据赋值给frame的各个参数
目前只分析到rtp_common_read()函数,下面的就是从底层中读取数据了
sofia模块使用sofia_read_video_frame()函数来读取视频数据
在函数内部调用switch_core_media_read_frame函数
现在再来看,mod_sofia模块中对音频和视频的读写处理
和上面的源代码是差不多的.
分析switch_core_session.c中的会话
switch_core_session_request_uuid()分析