res_pjsip_rfc3326.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * Joshua Colp <[email protected]>
 *
 * 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/causes.h"
#include "asterisk/threadpool.h"

static void rfc3326_use_reason_header(struct ast_sip_session *session, struct pjsip_rx_data *rdata)
{
   static const pj_str_t str_reason = { "Reason", 6 };
   pjsip_generic_string_hdr *header;
   char buf[20];
   char *cause;
   char *text;
   int code;

   header = pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &str_reason, NULL);
   for (; header;
      header = pjsip_msg_find_hdr_by_name(rdata->msg_info.msg, &str_reason, header->next)) {
      ast_copy_pj_str(buf, &header->hvalue, sizeof(buf));
      cause = ast_skip_blanks(buf);

      if (strncasecmp(cause, "Q.850", 5) || !(cause = strstr(cause, "cause="))) {
         continue;
      }

      /* If text is present get rid of it */
      if ((text = strstr(cause, ";"))) {
         *text = '\0';
      }

      if (sscanf(cause, "cause=%30d", &code) != 1) {
         continue;
      }

      ast_channel_hangupcause_set(session->channel, code & 0x7f);
      break;
   }
}

static int rfc3326_incoming_request(struct ast_sip_session *session, struct pjsip_rx_data *rdata)
{
   if ((pjsip_method_cmp(&rdata->msg_info.msg->line.req.method, &pjsip_bye_method) &&
        pjsip_method_cmp(&rdata->msg_info.msg->line.req.method, &pjsip_cancel_method)) ||
       !session->channel) {
      return 0;
   }

   rfc3326_use_reason_header(session, rdata);

   return 0;
}

static void rfc3326_incoming_response(struct ast_sip_session *session, struct pjsip_rx_data *rdata)
{
   struct pjsip_status_line status = rdata->msg_info.msg->line.status;

   if ((status.code < 300) || !session->channel) {
      return;
   }

   rfc3326_use_reason_header(session, rdata);
}

static void rfc3326_add_reason_header(struct ast_sip_session *session, struct pjsip_tx_data *tdata)
{
   char buf[20];

   if (ast_channel_hangupcause(session->channel) == AST_CAUSE_ANSWERED_ELSEWHERE) {
      ast_sip_add_header(tdata, "Reason", "SIP;cause=200;text=\"Call completed elsewhere\"");
   }

   if (session->endpoint && session->endpoint->suppress_q850_reason_headers) {
      ast_debug(1, "A Q.850 '%s'(%i) Reason header was suppresed for endpoint '%s'\n",
         ast_cause2str((ast_channel_hangupcause(session->channel) & 0x7f)),
         (ast_channel_hangupcause(session->channel) & 0x7f),
         ast_sorcery_object_get_id(session->endpoint));
   } else {
      snprintf(buf, sizeof(buf), "Q.850;cause=%i", ast_channel_hangupcause(session->channel) & 0x7f);
      ast_sip_add_header(tdata, "Reason", buf);
   }
}

static void rfc3326_outgoing_request(struct ast_sip_session *session, struct pjsip_tx_data *tdata)
{
   if ((pjsip_method_cmp(&tdata->msg->line.req.method, &pjsip_bye_method)
         && pjsip_method_cmp(&tdata->msg->line.req.method, &pjsip_cancel_method))
      || !session->channel
      /*
       * The session->channel has been seen to go away on us between
       * checks so we must also be running under the call's serializer
       * thread.
       */
      || session->serializer != ast_threadpool_serializer_get_current()) {
      return;
   }

   rfc3326_add_reason_header(session, tdata);
}

static void rfc3326_outgoing_response(struct ast_sip_session *session, struct pjsip_tx_data *tdata)
{
   struct pjsip_status_line status = tdata->msg->line.status;

   if (status.code < 300
      || !session->channel
      || session->serializer != ast_threadpool_serializer_get_current()) {
      return;
   }

   rfc3326_add_reason_header(session, tdata);
}

static struct ast_sip_session_supplement rfc3326_supplement = {
   .incoming_request = rfc3326_incoming_request,
   .incoming_response = rfc3326_incoming_response,
   .outgoing_request = rfc3326_outgoing_request,
   .outgoing_response = rfc3326_outgoing_response,
};

static int load_module(void)
{
   ast_sip_session_register_supplement(&rfc3326_supplement);
   return AST_MODULE_LOAD_SUCCESS;
}

static int unload_module(void)
{
   ast_sip_session_unregister_supplement(&rfc3326_supplement);
   return 0;
}

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP RFC3326 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",
);