The Sofia__freeswitch of FreeSWITCH kernel research

the Sofia of FreeSWITCH kernel research

call flow involves content

1, received the nua_i_invite of a, returned 407, as follows:

Sofia_handle_sip_i_invite =>sofia_reg_handle_register => sofia_reg_auth_challenge => 407

2, received the nua_i_invite of a, returned 180, as follows:

Sofia_handle_sip_i_invite =>sofia_reg_handle_register => Sofia_reg_parse_auth

Processing Nua_i_state messages
Sofia.c:sofia_handle_sip_i_state
...
Mod_dialplan_xml.c:dialplan_hunt (Ring_ready)
Resolves the dialing scheme, executes the Lua script, and sets the channel variables.
...
Send 180 Event

Data tables involved:
Sip_registrations, Ip_dialogs

3, send invite to B extension, specific as follows:
Processing Nua_r_invite messages
Sofia_handle_sip_r_invite => originate_on_routing
Data tables involved:
Sip_dialogs

4, B answer, the two sides call, specific as follows:

Sofia_receive_message:switch_message_indicate_answer

=>sofia_answer_channel

=>sofia_glue_tech_choose_port

=>sofia_glue_set_local_sdp

=>sofia_glue_activate_rtp

Coding Negotiation Process

This describes the following negotiation process to match the FreeSWITCH default codec, to find the support type's specific rate information from the loaded module

Sofia_handle_sip_i_invite
=> Sofia_glue_tech_prepare_codecs
=> switch_loadable_module_get_codecs_sorted negotiated to be called SDP

Sofia_glue_do_invite
=> Sofia_glue_tech_prepare_codecs
=> switch_loadable_module_get_codecs_sorted

Ocodec +codec_string generates m headers and sends invite containing the SDP

Sofia_glue_do_invite
=> SOFIA_GLUE_SET_LOCAL_SDP
=> generate_m
=> Nua_invite Negotiation OK SDP

Sofia_answer_channel
=> Sofia_glue_tech_prepare_codecs
=> switch_loadable_module_get_codecs_sorted

Media Interaction RTP Data interaction

Audio_bridge_on_exchange_media
=> Audio_bridge_thread

Send and receive audio data
=> Switch_core_session_read_frame
=> Session->endpoint_interface->io_routines->read_frame namely: Sofia_read_frame

=> Switch_core_session_write_frame
=> Perform_write
=> Session->endpoint_interface->io_routines->write_frame namely: Sofia_write_frame

Send and receive video data
1, start the thread
=> Launch_video
=> Video_bridge_thread

2, send and receive data
=> Switch_core_session_read_video_frame
=>session->endpoint_interface->io_routines->read_video_frame
namely: Sofia_read_video_frame

=>switch_core_session_write_video_frame
=> Session->endpoint_interface->io_routines->write_video_frame
That is: Sofia_write_video_frame terminate the RTP interaction

Audio_bridge_thread
=> Switch_core_session_kill_channel (Session_b, switch_sig_break);
namely: Switch_core_session_perform_kill_channel
=> Session->endpoint_interface->io_routines->kill_channel
namely: Sofia_kill_channel
=> switch_rtp_break Sofia Protocol Stack protocol stack structure diagram

NUA: Basic SIP User Agent functionality that includes call management, messaging, and event retrieval.
The Nta:sofia SIP Transaction API (NTA) provides a simple interface for SIP transactions, transport, and information processing.
Tport: This module contains a common transport interface used by the SIP,RTSP and HTTP protocols, which is the abstraction layer between the protocol stack and the Transport Protocol implementation. SIP Signaling Specific process

Scene Description: A call B, b after the call after a period of time, hang up the phone. A Send INVITE Request

Tport.c:tport_recv_data
Nta.c:agent_recv_request FS Response 100 to a ext

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 Send authentication request to a ext.

Nua_application_event

Processing Nua_i_invite messages

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

Reply 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

Send 407 to extension a

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 ext. Send ACK
Nta.c:agent_recv_message
Nta.c:agent_recv_request

· A extension resend invite request, additional authentication information
Tport.c:tport_recv_data
Nta.c:agent_recv_request

· FS Response 100 to extension a

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 send INVITE to extension b

Switch_ivr_originate.c:switch_ivr_originate

Sofia_on_init
Sofia_glue_do_invite
Nua_invite:nua_r_invite message
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
...
Perform a Send Invite request
Nta.c:outgoing_send
Tport_tsend

Call State (b): init-> calling B extension response 180 to FS
Tport_recv_event
Agent_recv_response

Processing Nua_r_invite messages

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 send 180 to a ext

Nua_session.c:signal_call_state_change
Nua_stack_tevent:nua_i_state
Nua_application_event

Processing Nua_i_invite messages

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

Processing Nua_i_state messages
Sofia.c:sofia_handle_sip_i_state
...
Mod_dialplan_xml.c:dialplan_hunt (Ring_ready)
Resolves the dialing scheme, executes the Lua script, and sets the channel variables.
...

Send 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 Send Okl
Tport_recv_event
Agent_recv_response

Processing Nua_r_invite messages

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 send ack to B
Nua_ack
Nua_signal:nua_r_ack
Outgoing_send
Tport_tsend

Call State (A): Received-> early
Call State (B): Completing-> ready FS send OK to 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: Performing recording operations B
...
Auto_record.lua: Performing recording Operations A
...
Sofia_receive_message (Switch_message_indicate_answer)
...
Send 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 response ack
Nta.c:agent_recv_message
Nta.c:agent_recv_request

Call State (A): Completed-> ready

· After the call for a while, a actively send bye
Tport_recv_event
Agent_recv_message
Agent_recv_request
...
Sofia_on_hangup

· FS Send bye to B
Nua_bye:nua_r_bye
Nua_stack_signal
Outgoing_send
Tport_tsend

· FS Send OK to a
Nta:sent 200OK for BYE
Tport_tsend

Call State (A): Ready-> terminating
Call State (A): Terminated B sends OK to FS, responds to hang up request
Nta:received OK for BYE

State change:
Call State (B): Ready-> terminating
Call State (B): terminating-> terminated