#coturn

COTURN CT-01

Today "he" arrived, the COTURN CT-01 turntable. After unpacking, the configuration and installation with the portable speakers from Revox (A100 & B100) took place. A first test listening was done with Dark Side Of The Moon.

udp_server_input_handler - this is the entry point to handling network events: here we receive udp packet, and pass it (the message it contains) to handle_udp_packet

handle_udp_packet tries to acquire child socket; if not exists, it creates it, attaches it to the message, and passes the latter to open_client_connection_session; if exists, it again attaches it to the message, and passes the message to client_input_handler

open_client_connection_session creates new session, set session's client_socket field, registers socket's read handler, sets socket's session, and passes the message to client_input_handler

client_input_handler basically passes the message to read_client_connection

read_client_connection for channel messages, it just passes them to the peer, for command messages, it passes them to handle_turn_command, and possibly replies to the message

handle_turn_command - there are two types of messages: requests and indication messages; here we're basically passing handling of each type of message to corresponding function, if authentication and other security concerns are satisfied

check_stun_auth the authentication is handled by a separate (auth) thread; so, relay thread sends data to auth thread, auth thread authenticates the user (particularly, validates the timestamp), and sends the reply back which gets passed to resume_processing_after_username_check function

Generally, the workflow is as follows:

client sends BINDING packet, the session gets created

client sends ALLOCATE packet, server checks if user is authenticated, as he's not it postpones the reply (401)

client sends ALLOCATE packet again, gets authenticated, server allocates relay address