Freeswitch核心研究之sofia__freeswitch

Freeswitch核心研究之sofia

呼叫流程涉及內容

1、收到A的nua_i_invite，返回407，具體如下:

sofia_handle_sip_i_invite =>sofia_reg_handle_register => sofia_reg_auth_challenge => 407

2、收到A的nua_i_invite，返回180，具體如下：

sofia_handle_sip_i_invite =>sofia_reg_handle_register => sofia_reg_parse_auth

處理nua_i_state訊息
sofia.c : sofia_handle_sip_i_state
...
mod_dialplan_xml.c : dialplan_hunt (ring_ready)
解析撥號方案，執行lua指令碼，設定通道變數。
…
發送180事件

涉及資料表：
sip_registrations、ip_dialogs

3、發送invite給B分機，具體如下：
處理nua_r_invite訊息
sofia_handle_sip_r_invite => originate_on_routing
涉及資料表：
sip_dialogs

4、 B應答，雙方通話，具體如下：

sofia_receive_message :SWITCH_MESSAGE_INDICATE_ANSWER              

    =>sofia_answer_channel

        =>sofia_glue_tech_choose_port

        =>sofia_glue_set_local_sdp

        =>sofia_glue_activate_rtp

編碼協商過程

這裡描述下後協商流程 先匹配freeswitch預設的codec，從載入的模組中尋找支援類型的具體碼率資訊

sofia_handle_sip_i_invite
=> sofia_glue_tech_prepare_codecs
=> switch_loadable_module_get_codecs_sorted 協商發給被叫的sdp

sofia_glue_do_invite
=> sofia_glue_tech_prepare_codecs
=> switch_loadable_module_get_codecs_sorted

    ocodec +codec_string     產生M頭，並發送包含sdp的invite

sofia_glue_do_invite
=> sofia_glue_set_local_sdp
=> generate_m
=> nua_invite 協商200 OK的sdp

sofia_answer_channel
=> sofia_glue_tech_prepare_codecs
=> switch_loadable_module_get_codecs_sorted

媒體互動 RTP資料互動

audio_bridge_on_exchange_media
=> audio_bridge_thread

收發音頻資料
=> switch_core_session_read_frame
=> session->endpoint_interface->io_routines->read_frame 即： sofia_read_frame

=> switch_core_session_write_frame
=> perform_write
=> session->endpoint_interface->io_routines->write_frame 即： sofia_write_frame

收發視頻資料
1、啟動線程
=> launch_video
=> video_bridge_thread

2、收發資料
=> switch_core_session_read_video_frame
=>session->endpoint_interface->io_routines->read_video_frame
即：sofia_read_video_frame

=>switch_core_session_write_video_frame
=> session->endpoint_interface->io_routines->write_video_frame
即：sofia_write_video_frame 終止RTP互動

audio_bridge_thread
=> switch_core_session_kill_channel(session_b, SWITCH_SIG_BREAK);
即：switch_core_session_perform_kill_channel
=> session->endpoint_interface->io_routines->kill_channel
即 : sofia_kill_channel
=> switch_rtp_break Sofia協議棧 協議棧結構圖

NUA : 基本的SIP使用者代理程式的功能，其功能包括呼叫管理，訊息和事件檢索。
NTA : sofia SIP事務API（NTA）提供了簡單的介面的SIP事務，傳輸和資訊處理。
Tport : 該模組包含一個由SIP，RTSP和HTTP協議使用的通用傳輸介面，這是一個協議棧和傳輸協議實現之間的抽象層。 SIP信令具體流程

情境描述： A 呼叫 B ，B接通後通話一段時間後，掛斷電話。 A 發送 INVITE 請求

tport.c : tport_recv_data
nta.c : agent_recv_request FS回應100給A分機

nua_server.c : nua_stack_process_request
nua_server.c : SR_STATUS1(sr, SIP_100_TRYING)
nta.c : nta_incoming_treply
nta.c : incoming_reply
tport.c: tport_tsend FS發送認證請求給A分機

nua_application_event

處理nua_i_invite訊息

sofia.c : sofia_process_dispatch_event
sofia.c : our_sofia_event_callback
sofia.c : sofia_handle_sip_i_invite
sofia.c : sofia_reg_handle_register
sofia_reg.c : sofia_reg_auth_challenge

回複407

nua.c : nua_respond
nua_stack.c : nua_signal
nua_stack.c : nua_stack_signal
nua_server.c : nua_stack_respond
nua_server.c : nua_server_respond

發送407給A分機

nua_invite_server_respond
nua_base_server_respond
nta_incoming_mreply
incoming_reply
tport_tsend
tport_resolve
tport_by_addrinfo
tport_prepare_and_send
tport_send_msg
tport_vsend
sent 407 Proxy Authentication Required for INVITE (1)

call state(A) : init -> received
call state(A) : received -> terminated

·        A分機發送ACK
nta.c : agent_recv_message
nta.c : agent_recv_request

·        A分機重新發送 INVITE請求，附加認證資訊
tport.c : tport_recv_data
nta.c : agent_recv_request

·        FS回應100給A分機

nua_server.c : nua_stack_process_request
nua_server.c : SR_STATUS1(sr, SIP_100_TRYING)
nta.c : nta_incoming_treply
nta.c : incoming_reply
tport.c: tport_tsend FS發送 INVITE 給 B分機

switch_ivr_originate.c : switch_ivr_originate

sofia_on_init
sofia_glue_do_invite
nua_invite : nua_r_invite 訊息
nua_signal

sofia.c : sofia_process_dispatch_event
sofia.c : our_sofia_event_callback
sofia.c : sofia_handle_sip_r_invite
...
sofia_on_init
sofia_on_routing
switch_ivr_originate.c ：originate_on_routing
...
nua_stack_signal
nua_stack_invite
...
nta_leg_tcreate
...
執行發送invite請求
nta.c : outgoing_send
tport_tsend

call state(B) : init -> calling B分機回應180給FS
tport_recv_event
agent_recv_response

處理nua_r_invite 訊息

sofia.c : sofia_process_dispatch_event
sofia.c : our_sofia_event_callback
sofia.c : sofia_handle_sip_r_invite

call state(B) : calling -> proceeding FS發送180給A分機

nua_session.c : signal_call_state_change
nua_stack_tevent : nua_i_state
nua_application_event

處理nua_i_invite訊息

sofia.c : sofia_process_dispatch_event
sofia.c : our_sofia_event_callback
sofia.c : sofia_handle_sip_i_invite
sofia_reg.c : sofia_reg_handle_register
sofia_reg.c : sofia_reg_parse_auth

處理nua_i_state訊息
sofia.c : sofia_handle_sip_i_state
...
mod_dialplan_xml.c : dialplan_hunt (ring_ready)
解析撥號方案，執行lua指令碼，設定通道變數。
…

發送180
switch_channel_mark_ring_ready

nua_invite_server_respond
nua_base_server_respond
nta_incoming_mreply
incoming_reply
tport_tsend
tport_resolve
tport_by_addrinfo
tport_prepare_and_send
tport_send_msg
tport_vsend

call state(A) : init -> received

 B發送200 okl
tport_recv_event
agent_recv_response

處理 nua_r_invite訊息

sofia.c : sofia_process_dispatch_event
sofia.c : our_sofia_event_callback
sofia.c : sofia_handle_sip_r_invite

call state(B) : proceeding -> completing FS發送ACK給B
nua_ack
nua_signal : nua_r_ack
outgoing_send
tport_tsend

call state(A) : received -> early
call state(B) : completing -> ready FS發送200 OK給A
sofia_glue_tech_set_codec
switch_rtp_create
sofia_glue_negotiate_sdp
sofia_glue_activate_rtp
...
switch_channel_perform_answer : SWITCH_MESSAGE_INDICATE_ANSWER
switch_channel_perform_mark_answered
...
auto_record.lua ： 執行錄音操作B
...
auto_record.lua ： 執行錄音操作A
...
sofia_receive_message (SWITCH_MESSAGE_INDICATE_ANSWER)
...
發送200 OK
nua_respond : 200
nua_signal : nua_r_respond
nua_stack_signal
nua_stack_respond
nua_server_respond
nta_incoming_treply
nta_incoming_mreply
incoming_reply
tport_tsend

call state(A) : early -> completed A回應ACK
nta.c : agent_recv_message
nta.c : agent_recv_request

call state(A) : completed -> ready

·        通話一段時間後，A主動發送BYE
tport_recv_event
agent_recv_message
agent_recv_request
...
sofia_on_hangup

·        FS發送BYE給B
nua_bye : nua_r_bye
nua_stack_signal
outgoing_send
tport_tsend

·        FS發送200 OK給A
nta ： sent 200OK for BYE
tport_tsend

call state(A) : ready -> terminating
call state(A) : terminated B發送200 OK給FS，回應掛斷請求
nta: received 200 OK for BYE

狀態變化：
call state(B) : ready -> terminating
call state(B) : terminating -> terminated