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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2013, Digium, Inc.
*
* Joshua Colp <jcolp@digium.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*** MODULEINFO
<support_level>core</support_level>
***/
#include "asterisk.h"
#include <pjsip.h>
#include <pjsip_ua.h>
#include "asterisk/res_sip.h"
#include "asterisk/module.h"
#include "asterisk/acl.h"
static pj_bool_t nat_on_rx_request(pjsip_rx_data *rdata)
{
RAII_VAR(struct ast_sip_endpoint *, endpoint, ast_pjsip_rdata_get_endpoint(rdata), ao2_cleanup);
pjsip_contact_hdr *contact;
if (!endpoint) {
return PJ_FALSE;
}
if (endpoint->rewrite_contact && (contact = pjsip_msg_find_hdr(rdata->msg_info.msg, PJSIP_H_CONTACT, NULL)) &&
(PJSIP_URI_SCHEME_IS_SIP(contact->uri) || PJSIP_URI_SCHEME_IS_SIPS(contact->uri))) {
pjsip_sip_uri *uri = pjsip_uri_get_uri(contact->uri);
pj_cstr(&uri->host, rdata->pkt_info.src_name);
uri->port = rdata->pkt_info.src_port;
}
if (endpoint->force_rport) {
rdata->msg_info.via->rport_param = 0;
}
return PJ_FALSE;
}
/*! \brief Structure which contains information about a transport */
struct request_transport_details {
/*! \brief Type of transport */
enum ast_sip_transport_type type;
/*! \brief Potential pointer to the transport itself, if UDP */
pjsip_transport *transport;
/*! \brief Potential pointer to the transport factory itself, if TCP/TLS */
pjsip_tpfactory *factory;
/*! \brief Local address for transport */
pj_str_t local_address;
/*! \brief Local port for transport */
int local_port;
};
/*! \brief Callback function for finding the transport the request is going out on */
static int find_transport_in_use(void *obj, void *arg, int flags)
{
struct ast_sip_transport *transport = obj;
struct request_transport_details *details = arg;
/* If an explicit transport or factory matches then this is what is in use, if we are unavailable
* to compare based on that we make sure that the type is the same and the source IP address/port are the same
*/
if ((details->transport && details->transport == transport->state->transport) ||
(details->factory && details->factory == transport->state->factory) ||
((details->type == transport->type) && (transport->state->factory) &&
!pj_strcmp(&transport->state->factory->addr_name.host, &details->local_address) &&
transport->state->factory->addr_name.port == details->local_port)) {
return CMP_MATCH | CMP_STOP;
}
return 0;
}
/*! \brief Helper function which returns the SIP URI of a Contact header */
static pjsip_sip_uri *nat_get_contact_sip_uri(pjsip_tx_data *tdata)
{
pjsip_contact_hdr *contact = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_CONTACT, NULL);
if (!contact || (!PJSIP_URI_SCHEME_IS_SIP(contact->uri) && !PJSIP_URI_SCHEME_IS_SIPS(contact->uri))) {
return NULL;
}
return pjsip_uri_get_uri(contact->uri);
}
/*! \brief Structure which contains hook details */
struct nat_hook_details {
/*! \brief Outgoing message itself */
pjsip_tx_data *tdata;
/*! \brief Chosen transport */
struct ast_sip_transport *transport;
};
/*! \brief Callback function for invoking hooks */
static int nat_invoke_hook(void *obj, void *arg, int flags)
{
struct ast_sip_nat_hook *hook = obj;
struct nat_hook_details *details = arg;
if (hook->outgoing_external_message) {
hook->outgoing_external_message(details->tdata, details->transport);
}
return 0;
}
static pj_status_t nat_on_tx_message(pjsip_tx_data *tdata)
{
RAII_VAR(struct ao2_container *, transports, NULL, ao2_cleanup);
RAII_VAR(struct ast_sip_transport *, transport, NULL, ao2_cleanup);
struct request_transport_details details = { 0, };
pjsip_via_hdr *via = NULL;
struct ast_sockaddr addr = { { 0, } };
pjsip_sip_uri *uri = NULL;
RAII_VAR(struct ao2_container *, hooks, NULL, ao2_cleanup);
/* If a transport selector is in use we know the transport or factory, so explicitly find it */
if (tdata->tp_sel.type == PJSIP_TPSELECTOR_TRANSPORT) {
details.transport = tdata->tp_sel.u.transport;
} else if (tdata->tp_sel.type == PJSIP_TPSELECTOR_LISTENER) {
details.factory = tdata->tp_sel.u.listener;
} else if (tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_UDP || tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_UDP6) {
/* Connectionless uses the same transport for all requests */
details.type = AST_SIP_TRANSPORT_UDP;
details.transport = tdata->tp_info.transport;
} else {
if (tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_TCP) {
details.type = AST_SIP_TRANSPORT_TCP;
} else if (tdata->tp_info.transport->key.type == PJSIP_TRANSPORT_TLS) {
details.type = AST_SIP_TRANSPORT_TLS;
} else {
/* Unknown transport type, we can't map and thus can't apply NAT changes */
return PJ_SUCCESS;
}
if ((uri = nat_get_contact_sip_uri(tdata))) {
details.local_address = uri->host;
details.local_port = uri->port;
} else if ((tdata->msg->type == PJSIP_REQUEST_MSG) &&
(via = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_VIA, NULL))) {
details.local_address = via->sent_by.host;
details.local_port = via->sent_by.port;
} else {
return PJ_SUCCESS;
}
if (!details.local_port) {
details.local_port = (details.type == AST_SIP_TRANSPORT_TLS) ? 5061 : 5060;
}
}
if (!(transports = ast_sorcery_retrieve_by_fields(ast_sip_get_sorcery(), "transport", AST_RETRIEVE_FLAG_MULTIPLE | AST_RETRIEVE_FLAG_ALL, NULL)) ||
!(transport = ao2_callback(transports, 0, find_transport_in_use, &details)) || !transport->localnet ||
ast_sockaddr_isnull(&transport->external_address)) {
return PJ_SUCCESS;
}
ast_sockaddr_parse(&addr, tdata->tp_info.dst_name, PARSE_PORT_FORBID);
ast_sockaddr_set_port(&addr, tdata->tp_info.dst_port);
/* See if where we are sending this request is local or not, and if not that we can get a Contact URI to modify */
if (ast_apply_ha(transport->localnet, &addr) != AST_SENSE_ALLOW) {
return PJ_SUCCESS;
}
/* Update the contact header with the external address */
if (uri || (uri = nat_get_contact_sip_uri(tdata))) {
pj_strdup2(tdata->pool, &uri->host, ast_sockaddr_stringify_host(&transport->external_address));
if (transport->external_signaling_port) {
uri->port = transport->external_signaling_port;
}
}
/* Update the via header if relevant */
if ((tdata->msg->type == PJSIP_REQUEST_MSG) && (via || (via = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_VIA, NULL)))) {
pj_strdup2(tdata->pool, &via->sent_by.host, ast_sockaddr_stringify_host(&transport->external_address));
if (transport->external_signaling_port) {
via->sent_by.port = transport->external_signaling_port;
}
}
/* Invoke any additional hooks that may be registered */
if ((hooks = ast_sorcery_retrieve_by_fields(ast_sip_get_sorcery(), "nat_hook", AST_RETRIEVE_FLAG_MULTIPLE | AST_RETRIEVE_FLAG_ALL, NULL))) {
struct nat_hook_details hook_details = {
.tdata = tdata,
.transport = transport,
};
ao2_callback(hooks, 0, nat_invoke_hook, &hook_details);
}
return PJ_SUCCESS;
}
static pjsip_module nat_module = {
.name = { "NAT", 3 },
.id = -1,
.priority = PJSIP_MOD_PRIORITY_TSX_LAYER - 2,
.on_rx_request = nat_on_rx_request,
.on_tx_request = nat_on_tx_message,
.on_tx_response = nat_on_tx_message,
};
static int load_module(void)
{
ast_sip_register_service(&nat_module);
return AST_MODULE_LOAD_SUCCESS;
}
static int unload_module(void)
{
ast_sip_unregister_service(&nat_module);
return 0;
}
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "SIP NAT Support",
.load = load_module,
.unload = unload_module,
.load_pri = AST_MODPRI_APP_DEPEND,
);
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