res_pjsip_path.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * Kinsey Moore <kmoore@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
    <depend>pjproject</depend>
    <depend>res_pjsip</depend>
    <depend>res_pjsip_session</depend>
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include <pjsip.h>
#include <pjsip_ua.h>
 
#include "asterisk/res_pjsip.h"
#include "asterisk/res_pjsip_session.h"
#include "asterisk/module.h"
#include "asterisk/strings.h"
 
static const pj_str_t PATH_NAME = { "Path", 4 };
static pj_str_t PATH_SUPPORTED_NAME = { "path", 4 };
 
static struct ast_sip_aor *find_aor(struct ast_sip_contact *contact)
{
    if (!contact) {
        return NULL;
    }
    if (ast_strlen_zero(contact->aor)) {
        return NULL;
    }
 
    return ast_sip_location_retrieve_aor(contact->aor);
}
 
static struct ast_sip_aor *find_aor2(struct ast_sip_endpoint *endpoint, pjsip_uri *uri)
{
    char *configured_aors, *aor_name;
    const pj_str_t *uri_username;
    const pj_str_t *uri_hostname;
    char *domain_name;
    char *username;
    struct ast_str *id = NULL;
 
    if (ast_strlen_zero(endpoint->aors)) {
        return NULL;
    }
 
    uri_hostname = ast_sip_pjsip_uri_get_hostname(uri);
    domain_name = ast_alloca(uri_hostname->slen + 1);
    ast_copy_pj_str(domain_name, uri_hostname, uri_hostname->slen + 1);
 
    uri_username = ast_sip_pjsip_uri_get_username(uri);
    username = ast_alloca(uri_username->slen + 1);
    ast_copy_pj_str(username, uri_username, uri_username->slen + 1);
 
    /*
     * We may want to match without any user options getting
     * in the way.
     */
    AST_SIP_USER_OPTIONS_TRUNCATE_CHECK(username);
 
    configured_aors = ast_strdupa(endpoint->aors);
 
    /* Iterate the configured AORs to see if the user or the user+domain match */
    while ((aor_name = ast_strip(strsep(&configured_aors, ",")))) {
        struct ast_sip_domain_alias *alias = NULL;
 
        if (ast_strlen_zero(aor_name)) {
            continue;
        }
 
        if (!strcmp(username, aor_name)) {
            break;
        }
 
        if (!id && !(id = ast_str_create(strlen(username) + uri_hostname->slen + 2))) {
            aor_name = NULL;
            break;
        }
 
        ast_str_set(&id, 0, "%s@", username);
        if ((alias = ast_sorcery_retrieve_by_id(ast_sip_get_sorcery(), "domain_alias", domain_name))) {
            ast_str_append(&id, 0, "%s", alias->domain);
            ao2_cleanup(alias);
        } else {
            ast_str_append(&id, 0, "%s", domain_name);
        }
 
        if (!strcmp(aor_name, ast_str_buffer(id))) {
            break;
        }
    }
    ast_free(id);
 
    if (ast_strlen_zero(aor_name)) {
        return NULL;
    }
 
    return ast_sip_location_retrieve_aor(aor_name);
}
 
static struct ast_sip_contact *find_contact(struct ast_sip_aor *aor, pjsip_uri *uri)
{
    struct ao2_iterator it_contacts;
    struct ast_sip_contact *contact;
    char contact_buf[512];
    int contact_buf_len;
    int res = 0;
 
    RAII_VAR(struct ao2_container *, contacts, NULL, ao2_cleanup);
 
    if (!(contacts = ast_sip_location_retrieve_aor_contacts(aor))) {
        /* No contacts are available, skip it as well */
        return NULL;
    } else if (!ao2_container_count(contacts)) {
        /* We were given a container but no contacts are in it... */
        return NULL;
    }
 
    contact_buf_len = pjsip_uri_print(PJSIP_URI_IN_CONTACT_HDR, uri, contact_buf, 512);
    contact_buf[contact_buf_len] = '\0';
 
    it_contacts = ao2_iterator_init(contacts, 0);
    for (; (contact = ao2_iterator_next(&it_contacts)); ao2_ref(contact, -1)) {
        if (!strcmp(contact_buf, contact->uri)) {
            res = 1;
            break;
        }
    }
    ao2_iterator_destroy(&it_contacts);
    if (!res) {
        return NULL;
    }
    return contact;
}
 
 
/*!
 * \brief Get the path string associated with this contact and tdata
 *
 * \param pool
 * \param contact The URI identifying the associated contact
 * \param path_str The place to store the retrieved path information
 *
 * \retval zero on success
 * \retval non-zero on failure or no available path information
 */
static int path_get_string(pj_pool_t *pool, struct ast_sip_contact *contact, pj_str_t *path_str)
{
    if (!contact || ast_strlen_zero(contact->path)) {
        return -1;
    }
 
    *path_str = pj_strdup3(pool, contact->path);
    return 0;
}
 
static int add_supported(pjsip_tx_data *tdata)
{
    pjsip_supported_hdr *hdr;
    int i;
 
    hdr = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_SUPPORTED, NULL);
    if (!hdr) {
        /* insert a new Supported header */
        hdr = pjsip_supported_hdr_create(tdata->pool);
        if (!hdr) {
            return -1;
        }
 
        pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr *)hdr);
    }
 
    /* Don't add the value if it's already there */
    for (i = 0; i < hdr->count; ++i) {
        if (pj_stricmp(&hdr->values[i], &PATH_SUPPORTED_NAME) == 0) {
            return 0;
        }
    }
 
    if (hdr->count >= PJSIP_GENERIC_ARRAY_MAX_COUNT) {
        return -1;
    }
 
    /* add on to the existing Supported header */
    pj_strassign(&hdr->values[hdr->count++], &PATH_SUPPORTED_NAME);
 
    return 0;
}
 
/*!
 * \internal
 * \brief Adds a Route header to an outgoing request if
 * path information is available.
 *
 * \param endpoint The endpoint with which this request is associated
 * \param contact The contact to which this request is being sent
 * \param tdata The outbound request
 */
static void path_outgoing_request(struct ast_sip_endpoint *endpoint, struct ast_sip_contact *contact, pjsip_tx_data *tdata)
{
    RAII_VAR(struct ast_sip_aor *, aor, NULL, ao2_cleanup);
 
    if (!endpoint) {
        return;
    }
 
    aor = find_aor(contact);
    if (!aor) {
        aor = find_aor2(endpoint, tdata->msg->line.req.uri);
    }
    if (!aor || !aor->support_path) {
        return;
    }
 
    if (add_supported(tdata)) {
        return;
    }
 
    if (!contact) {
        contact = find_contact(aor, tdata->msg->line.req.uri);
        if (contact) {
            if (!ast_strlen_zero(contact->path)) {
                ast_sip_set_outbound_proxy(tdata, contact->path);
            }
            ao2_ref(contact, -1);
            contact = NULL;
        }
    } else {
        if (!ast_strlen_zero(contact->path)) {
            ast_sip_set_outbound_proxy(tdata, contact->path);
        }
    }
}
 
static void path_session_outgoing_request(struct ast_sip_session *session, pjsip_tx_data *tdata)
{
    path_outgoing_request(session->endpoint, session->contact, tdata);
}
 
/*!
 * \internal
 * \brief Adds a path header to an outgoing 2XX response
 *
 * \param endpoint The endpoint to which the INVITE response is to be sent
 * \param contact The contact to which the INVITE response is to be sent
 * \param tdata The outbound INVITE response
 */
static void path_outgoing_response(struct ast_sip_endpoint *endpoint, struct ast_sip_contact *contact, pjsip_tx_data *tdata)
{
    struct pjsip_status_line status = tdata->msg->line.status;
    pj_str_t path_dup;
    pjsip_generic_string_hdr *path_hdr;
    RAII_VAR(struct ast_sip_aor *, aor, NULL, ao2_cleanup);
    pjsip_cseq_hdr *cseq = pjsip_msg_find_hdr(tdata->msg, PJSIP_H_CSEQ, NULL);
    const pj_str_t REGISTER_METHOD = {"REGISTER", 8};
 
    if (!endpoint
        || !pj_stristr(&REGISTER_METHOD, &cseq->method.name)
        || !PJSIP_IS_STATUS_IN_CLASS(status.code, 200)) {
        return;
    }
 
    aor = find_aor(contact);
    if (!aor || !aor->support_path || add_supported(tdata)
        || path_get_string(tdata->pool, contact, &path_dup)) {
        return;
    }
 
    path_hdr = pjsip_generic_string_hdr_create(tdata->pool, &PATH_NAME, &path_dup);
    if (!path_hdr) {
        return;
    }
 
    pjsip_msg_add_hdr(tdata->msg, (pjsip_hdr*)path_hdr);
}
 
static void path_session_outgoing_response(struct ast_sip_session *session, pjsip_tx_data *tdata)
{
    path_outgoing_response(session->endpoint, session->contact, tdata);
}
 
static struct ast_sip_supplement path_supplement = {
    .priority = AST_SIP_SUPPLEMENT_PRIORITY_CHANNEL - 100,
    .outgoing_request = path_outgoing_request,
    .outgoing_response = path_outgoing_response,
};
 
static struct ast_sip_session_supplement path_session_supplement = {
    .priority = AST_SIP_SUPPLEMENT_PRIORITY_CHANNEL - 100,
    .outgoing_request = path_session_outgoing_request,
    .outgoing_response = path_session_outgoing_response,
};
 
static int load_module(void)
{
    ast_sip_register_supplement(&path_supplement);
    ast_sip_session_register_supplement(&path_session_supplement);
 
    return AST_MODULE_LOAD_SUCCESS;
}
 
static int unload_module(void)
{
    ast_sip_unregister_supplement(&path_supplement);
    ast_sip_session_unregister_supplement(&path_session_supplement);
    return 0;
}
 
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Path Header Support",
    .support_level = AST_MODULE_SUPPORT_CORE,
    .load = load_module,
    .unload = unload_module,
    .load_pri = AST_MODPRI_APP_DEPEND,
    .requires = "res_pjsip,res_pjsip_session",
);