Hi,
I think that you should introduce a new function.
void ast_rtp_stun_request(struct ast_rtp *rtp,
     struct sockaddr_in *suggestion, const char *username)
{
	ast_rtp_stun_request_sock(rtp->xxx, suggestion, username);
	return;
}
void
ast_stun_request_sock(int sock, struct sockaddr_in *dest, ...)
{
	....
}
--HPS