The presence of Record-Route in re-invites is optional, thus it is important to make sure the dialog doesn't have a routset before rewriting the contact header. ASTERISK-28129 #close Change-Id: Ic8ceb54ccfc93f7e315e476c514a2c777f2da7dc
437 lines
14 KiB
C
437 lines
14 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 2013, Digium, Inc.
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*
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* Joshua Colp <jcolp@digium.com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*** MODULEINFO
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<depend>pjproject</depend>
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<depend>res_pjsip</depend>
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<support_level>core</support_level>
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***/
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#include "asterisk.h"
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#include <pjsip.h>
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#include <pjsip_ua.h>
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#include "asterisk/res_pjsip.h"
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#include "asterisk/res_pjsip_session.h"
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#include "asterisk/module.h"
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#include "asterisk/acl.h"
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static void rewrite_uri(pjsip_rx_data *rdata, pjsip_sip_uri *uri)
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{
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pj_cstr(&uri->host, rdata->pkt_info.src_name);
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uri->port = rdata->pkt_info.src_port;
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if (!strcasecmp("WSS", rdata->tp_info.transport->type_name)) {
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/* WSS is special, we don't want to overwrite the URI at all as it needs to be ws */
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} else if (strcasecmp("udp", rdata->tp_info.transport->type_name)) {
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uri->transport_param = pj_str(rdata->tp_info.transport->type_name);
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} else {
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uri->transport_param.slen = 0;
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}
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}
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/*
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* Update the Record-Route headers in the request or response and in the dialog
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* object if exists.
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*
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* When NAT is in use, the address of the next hop in the SIP may be incorrect.
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* To address this asterisk uses two strategies in parallel:
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* 1. intercept the messages at the transaction level and rewrite the
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* messages before arriving at the dialog layer
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* 2. after the application processing, update the dialog object with the
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* correct information
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*
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* The first strategy has a limitation that the SIP message may not have all
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* the information required to determine if the next hop is in the route set
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* or in the contact. Causing risk that asterisk will update the Contact on
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* receipt of an in-dialog message despite there being a route set saved in
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* the dialog.
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*
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* The second strategy has a limitation that not all UAC layers have interfaces
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* available to invoke this module after dialog creation. (pjsip_sesion does
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* but pjsip_pubsub does not), thus this strategy can't update the dialog in
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* all cases needed.
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*
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* The ideal solution would be to implement an "incomming_request" event
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* in pubsub module that can then pass the dialog object to this module
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* on SUBSCRIBE, this module then should add itself as a listener to the dialog
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* for the subsequent requests and responses & then be able to properly update
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* the dialog object for all required events.
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*/
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static int rewrite_route_set(pjsip_rx_data *rdata, pjsip_dialog *dlg)
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{
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pjsip_rr_hdr *rr = NULL;
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pjsip_sip_uri *uri;
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int res = -1;
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int ignore_rr = 0;
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int pubsub = 0;
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if (rdata->msg_info.msg->type == PJSIP_RESPONSE_MSG) {
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pjsip_hdr *iter;
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for (iter = rdata->msg_info.msg->hdr.prev; iter != &rdata->msg_info.msg->hdr; iter = iter->prev) {
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if (iter->type == PJSIP_H_RECORD_ROUTE) {
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rr = (pjsip_rr_hdr *)iter;
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break;
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}
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}
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} else if (pjsip_method_cmp(&rdata->msg_info.msg->line.req.method, &pjsip_register_method)) {
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rr = pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_RECORD_ROUTE, NULL);
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} else {
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/**
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* Record-Route header has no meaning in REGISTER requests
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* and should be ignored
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*/
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ignore_rr = 1;
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}
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if (!pjsip_method_cmp(&rdata->msg_info.cseq->method, &pjsip_subscribe_method) ||
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!pjsip_method_cmp(&rdata->msg_info.cseq->method, &pjsip_notify_method)) {
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/**
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* There is currently no good way to get the dlg object for a pubsub dialog
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* so we will just look at the rr & contact of the current message and
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* hope for the best
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*/
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pubsub = 1;
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}
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if (rr) {
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uri = pjsip_uri_get_uri(&rr->name_addr);
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rewrite_uri(rdata, uri);
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res = 0;
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}
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if (dlg && !pj_list_empty(&dlg->route_set) && !dlg->route_set_frozen) {
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pjsip_routing_hdr *route = dlg->route_set.next;
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uri = pjsip_uri_get_uri(&route->name_addr);
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rewrite_uri(rdata, uri);
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res = 0;
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}
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if (!dlg && !rr && !ignore_rr && !pubsub && rdata->msg_info.to->tag.slen){
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/**
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* Even if this message doesn't have any route headers
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* the dialog may, so wait until a later invocation that
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* has a dialog reference to make sure there isn't a
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* previously saved routset in the dialog before deciding
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* the contact needs to be modified
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*/
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res = 0;
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}
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return res;
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}
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static int rewrite_contact(pjsip_rx_data *rdata, pjsip_dialog *dlg)
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{
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pjsip_contact_hdr *contact;
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contact = pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_CONTACT, NULL);
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if (contact && !contact->star && (PJSIP_URI_SCHEME_IS_SIP(contact->uri) || PJSIP_URI_SCHEME_IS_SIPS(contact->uri))) {
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pjsip_sip_uri *uri = pjsip_uri_get_uri(contact->uri);
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rewrite_uri(rdata, uri);
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if (dlg && pj_list_empty(&dlg->route_set) && (!dlg->remote.contact
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|| pjsip_uri_cmp(PJSIP_URI_IN_REQ_URI, dlg->remote.contact->uri, contact->uri))) {
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dlg->remote.contact = (pjsip_contact_hdr*)pjsip_hdr_clone(dlg->pool, contact);
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dlg->target = dlg->remote.contact->uri;
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}
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return 0;
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}
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return -1;
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}
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static pj_bool_t handle_rx_message(struct ast_sip_endpoint *endpoint, pjsip_rx_data *rdata)
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{
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pjsip_dialog *dlg = pjsip_rdata_get_dlg(rdata);
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if (!endpoint) {
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return PJ_FALSE;
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}
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if (endpoint->nat.rewrite_contact) {
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/* rewrite_contact is intended to ensure we send requests/responses to
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* a routeable address when NAT is involved. The URI that dictates where
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* we send requests/responses can be determined either by Record-Route
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* headers or by the Contact header if no Record-Route headers are present.
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* We therefore will attempt to rewrite a Record-Route header first, and if
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* none are present, we fall back to rewriting the Contact header instead.
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*/
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if (rewrite_route_set(rdata, dlg)) {
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rewrite_contact(rdata, dlg);
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}
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}
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if (endpoint->nat.force_rport) {
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rdata->msg_info.via->rport_param = rdata->pkt_info.src_port;
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}
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return PJ_FALSE;
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}
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static pj_bool_t nat_on_rx_message(pjsip_rx_data *rdata)
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{
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pj_bool_t res;
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struct ast_sip_endpoint *endpoint;
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endpoint = ast_pjsip_rdata_get_endpoint(rdata);
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res = handle_rx_message(endpoint, rdata);
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ao2_cleanup(endpoint);
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return res;
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}
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/*! \brief Structure which contains information about a transport */
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struct request_transport_details {
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/*! \brief Type of transport */
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enum ast_transport type;
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/*! \brief Potential pointer to the transport itself, if UDP */
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pjsip_transport *transport;
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/*! \brief Potential pointer to the transport factory itself, if TCP/TLS */
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pjsip_tpfactory *factory;
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/*! \brief Local address for transport */
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pj_str_t local_address;
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/*! \brief Local port for transport */
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int local_port;
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};
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/*! \brief Callback function for finding the transport the request is going out on */
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static int find_transport_state_in_use(void *obj, void *arg, int flags)
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{
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struct ast_sip_transport_state *transport_state = obj;
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struct request_transport_details *details = arg;
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/* If an explicit transport or factory matches then this is what is in use, if we are unavailable
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* to compare based on that we make sure that the type is the same and the source IP address/port are the same
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*/
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if (transport_state && ((details->transport && details->transport == transport_state->transport) ||
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(details->factory && details->factory == transport_state->factory) ||
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((details->type == transport_state->type) && (transport_state->factory) &&
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!pj_strcmp(&transport_state->factory->addr_name.host, &details->local_address) &&
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transport_state->factory->addr_name.port == details->local_port))) {
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return CMP_MATCH;
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}
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return 0;
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}
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/*! \brief Helper function which returns the SIP URI of a Contact header */
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static pjsip_sip_uri *nat_get_contact_sip_uri(pjsip_tx_data *tdata)
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{
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pjsip_contact_hdr *contact = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_CONTACT, NULL);
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if (!contact || (!PJSIP_URI_SCHEME_IS_SIP(contact->uri) && !PJSIP_URI_SCHEME_IS_SIPS(contact->uri))) {
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return NULL;
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}
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return pjsip_uri_get_uri(contact->uri);
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}
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/*! \brief Structure which contains hook details */
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struct nat_hook_details {
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/*! \brief Outgoing message itself */
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pjsip_tx_data *tdata;
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/*! \brief Chosen transport */
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struct ast_sip_transport *transport;
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};
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/*! \brief Callback function for invoking hooks */
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static int nat_invoke_hook(void *obj, void *arg, int flags)
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{
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struct ast_sip_nat_hook *hook = obj;
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struct nat_hook_details *details = arg;
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if (hook->outgoing_external_message) {
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hook->outgoing_external_message(details->tdata, details->transport);
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}
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return 0;
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}
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static pj_status_t nat_on_tx_message(pjsip_tx_data *tdata)
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{
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RAII_VAR(struct ao2_container *, transport_states, NULL, ao2_cleanup);
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RAII_VAR(struct ast_sip_transport *, transport, NULL, ao2_cleanup);
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RAII_VAR(struct ast_sip_transport_state *, transport_state, NULL, ao2_cleanup);
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struct request_transport_details details = { 0, };
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pjsip_via_hdr *via = NULL;
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struct ast_sockaddr addr = { { 0, } };
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pjsip_sip_uri *uri = NULL;
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RAII_VAR(struct ao2_container *, hooks, NULL, ao2_cleanup);
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/* If a transport selector is in use we know the transport or factory, so explicitly find it */
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if (tdata->tp_sel.type == PJSIP_TPSELECTOR_TRANSPORT) {
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details.transport = tdata->tp_sel.u.transport;
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} else if (tdata->tp_sel.type == PJSIP_TPSELECTOR_LISTENER) {
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details.factory = tdata->tp_sel.u.listener;
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} else if (tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_UDP || tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_UDP6) {
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/* Connectionless uses the same transport for all requests */
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details.type = AST_TRANSPORT_UDP;
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details.transport = tdata->tp_info.transport;
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} else {
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if (tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_TCP) {
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details.type = AST_TRANSPORT_TCP;
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} else if (tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_TLS) {
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details.type = AST_TRANSPORT_TLS;
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} else {
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/* Unknown transport type, we can't map and thus can't apply NAT changes */
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return PJ_SUCCESS;
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}
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if ((uri = nat_get_contact_sip_uri(tdata))) {
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details.local_address = uri->host;
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details.local_port = uri->port;
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} else if ((tdata->msg->type == PJSIP_REQUEST_MSG) &&
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(via = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_VIA, NULL))) {
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details.local_address = via->sent_by.host;
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details.local_port = via->sent_by.port;
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} else {
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return PJ_SUCCESS;
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}
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if (!details.local_port) {
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details.local_port = (details.type == AST_TRANSPORT_TLS) ? 5061 : 5060;
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}
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}
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if (!(transport_states = ast_sip_get_transport_states())) {
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return PJ_SUCCESS;
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}
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if (!(transport_state = ao2_callback(transport_states, 0, find_transport_state_in_use, &details))) {
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return PJ_SUCCESS;
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}
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if (!(transport = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "transport", transport_state->id))) {
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return PJ_SUCCESS;
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}
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if (transport_state->localnet) {
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ast_sockaddr_parse(&addr, tdata->tp_info.dst_name, PARSE_PORT_FORBID);
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ast_sockaddr_set_port(&addr, tdata->tp_info.dst_port);
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/* See if where we are sending this request is local or not, and if not that we can get a Contact URI to modify */
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if (ast_sip_transport_is_local(transport_state, &addr)) {
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ast_debug(5, "Request is being sent to local address, skipping NAT manipulation\n");
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return PJ_SUCCESS;
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}
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}
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if (!ast_sockaddr_isnull(&transport_state->external_signaling_address)) {
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/* Update the contact header with the external address */
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if (uri || (uri = nat_get_contact_sip_uri(tdata))) {
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pj_strdup2(tdata->pool, &uri->host, ast_sockaddr_stringify_host(&transport_state->external_signaling_address));
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if (transport->external_signaling_port) {
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uri->port = transport->external_signaling_port;
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ast_debug(4, "Re-wrote Contact URI port to %d\n", uri->port);
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}
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}
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/* Update the via header if relevant */
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if ((tdata->msg->type == PJSIP_REQUEST_MSG) && (via || (via = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_VIA, NULL)))) {
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pj_strdup2(tdata->pool, &via->sent_by.host, ast_sockaddr_stringify_host(&transport_state->external_signaling_address));
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if (transport->external_signaling_port) {
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via->sent_by.port = transport->external_signaling_port;
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}
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}
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}
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/* Invoke any additional hooks that may be registered */
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if ((hooks = ast_sorcery_retrieve_by_fields(ast_sip_get_sorcery(), "nat_hook", AST_RETRIEVE_FLAG_MULTIPLE | AST_RETRIEVE_FLAG_ALL, NULL))) {
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struct nat_hook_details hook_details = {
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.tdata = tdata,
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.transport = transport,
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};
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ao2_callback(hooks, 0, nat_invoke_hook, &hook_details);
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}
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return PJ_SUCCESS;
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}
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static pjsip_module nat_module = {
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.name = { "NAT", 3 },
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.id = -1,
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.priority = PJSIP_MOD_PRIORITY_TSX_LAYER - 2,
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.on_rx_request = nat_on_rx_message,
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.on_rx_response = nat_on_rx_message,
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.on_tx_request = nat_on_tx_message,
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.on_tx_response = nat_on_tx_message,
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};
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/*! \brief Function called when an INVITE goes out */
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static int nat_incoming_invite_request(struct ast_sip_session *session, struct pjsip_rx_data *rdata)
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{
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if (session->inv_session->state == PJSIP_INV_STATE_INCOMING) {
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pjsip_dlg_add_usage(session->inv_session->dlg, &nat_module, NULL);
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}
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return 0;
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}
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/*! \brief Function called when an INVITE response comes in */
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static void nat_incoming_invite_response(struct ast_sip_session *session, struct pjsip_rx_data *rdata)
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{
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handle_rx_message(session->endpoint, rdata);
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}
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/*! \brief Function called when an INVITE comes in */
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static void nat_outgoing_invite_request(struct ast_sip_session *session, struct pjsip_tx_data *tdata)
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{
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if (session->inv_session->state == PJSIP_INV_STATE_NULL) {
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pjsip_dlg_add_usage(session->inv_session->dlg, &nat_module, NULL);
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}
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}
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/*! \brief Supplement for adding NAT functionality to dialog */
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static struct ast_sip_session_supplement nat_supplement = {
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.method = "INVITE",
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.priority = AST_SIP_SUPPLEMENT_PRIORITY_FIRST + 1,
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.incoming_request = nat_incoming_invite_request,
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.outgoing_request = nat_outgoing_invite_request,
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.incoming_response = nat_incoming_invite_response,
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};
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static int unload_module(void)
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{
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ast_sip_session_unregister_supplement(&nat_supplement);
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ast_sip_unregister_service(&nat_module);
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return 0;
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}
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static int load_module(void)
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{
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if (ast_sip_register_service(&nat_module)) {
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ast_log(LOG_ERROR, "Could not register NAT module for incoming and outgoing requests\n");
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return AST_MODULE_LOAD_DECLINE;
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}
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ast_sip_session_register_supplement(&nat_supplement);
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return AST_MODULE_LOAD_SUCCESS;
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}
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AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP NAT Support",
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.support_level = AST_MODULE_SUPPORT_CORE,
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.load = load_module,
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.unload = unload_module,
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.load_pri = AST_MODPRI_APP_DEPEND,
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.requires = "res_pjsip,res_pjsip_session",
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);
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