res_pjsip_session: Rewrite o= with external_media_address.

It now appends the external IP address on the
o= line of the SDP packet.  The decision was made to write
the numeric IP address as opposed to the RFC that states
the FQDN should be used if and when available.  We believe
the usage of literal IP address will help avoid
potential problems.

ASTERISK-27614 #close

Change-Id: I84f3360f3606b8c4e8d161edb228799ec0b8a302

res/res_pjsip_session.c

@@ -3168,7 +3168,7 @@ static void session_outgoing_nat_hook(pjsip_tx_data *tdata, struct ast_sip_trans
 		if (ast_sip_transport_is_local(transport_state, &our_sdp_addr) || !transport_state->localnet) {
 			ast_debug(5, "Setting external media address to %s\n", ast_sockaddr_stringify_host(&transport_state->external_media_address));
 			pj_strdup2(tdata->pool, &sdp->conn->addr, ast_sockaddr_stringify_host(&transport_state->external_media_address));
-			pj_strdup2(tdata->pool, &sdp->origin.addr, transport->external_media_address);
+			pj_strassign(&sdp->origin.addr, &sdp->conn->addr);
 		}
 	}