eXosip2_network man page

int eXosip_transport_set (osip_message_t *msg, const char *transport)
int eXosip_guess_localip (int family, char *address, int size)

Modify the transport protocol used to send SIP message.

Parameters:

msg The SIP message to modify
transport transport protocol to use ('UDP', 'TCP' or 'TLS')

Find the current localip (interface with default route).

Parameters:

family AF_INET or AF_INET6
address a string containing the local IP address.
size The size of the string