res_pjsip_dtmf_info.c

Go to the documentation of this file.

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * Jason Parker <[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"

static int is_media_type(pjsip_rx_data *rdata, char *subtype)
{
   return rdata->msg_info.ctype
      && !pj_strcmp2(&rdata->msg_info.ctype->media.type, "application")
      && !pj_strcmp2(&rdata->msg_info.ctype->media.subtype, subtype);
}

static void send_response(struct ast_sip_session *session,
           struct pjsip_rx_data *rdata, int code)
{
   pjsip_tx_data *tdata;
   pjsip_dialog *dlg = session->inv_session->dlg;

   if (pjsip_dlg_create_response(dlg, rdata, code,
                  NULL, &tdata) == PJ_SUCCESS) {
      struct pjsip_transaction *tsx = pjsip_rdata_get_tsx(rdata);
      pjsip_dlg_send_response(dlg, tsx, tdata);
   }
}

static char get_event(const char *c)
{
   unsigned int event;

   if (*c == '!' || *c == '*' || *c == '#' ||
       ('A' <= *c && *c <= 'D') ||
       ('a' <= *c && *c <= 'd')) {
      return *c;
   }

   if ((sscanf(c, "%30u", &event) != 1) || event > 16) {
      return '\0';
   }

   if (event < 10) {
      return *c;
   }

   switch (event) {
   case 10: return '*';
   case 11: return '#';
   case 16: return '!';
   }

   return 'A' + (event - 12);
}

static int dtmf_info_incoming_request(struct ast_sip_session *session, struct pjsip_rx_data *rdata)
{
   pjsip_msg_body *body = rdata->msg_info.msg->body;
   char buf[body ? body->len + 1 : 1];
   char *cur = buf;
   char *line;
   char event = '\0';
   unsigned int duration = 100;
   char is_dtmf, is_dtmf_relay, is_flash;
   int res;

   if (!session->channel) {
      return 0;
   }

   is_dtmf = is_media_type(rdata, "dtmf");
   is_dtmf_relay = is_media_type(rdata, "dtmf-relay");
   is_flash = is_media_type(rdata, "hook-flash");

   if (!is_flash && !is_dtmf && !is_dtmf_relay) {
      return 0;
   }

   if (!body || !body->len) {
      /* need to return 200 OK on empty body */
      send_response(session, rdata, 200);
      return 1;
   }

   res = body->print_body(body, buf, body->len);
   if (res < 0) {
      send_response(session, rdata, 500);
      return 1;
   }
   buf[res] = '\0';

   if (is_dtmf) {
      /* directly use what is in the message body */
      event = get_event(cur);
   } else if (is_dtmf_relay) { /* content type = application/dtmf-relay */
      while ((line = strsep(&cur, "\r\n"))) {
         char *c;

         if (!(c = strchr(line, '='))) {
            continue;
         }

         *c++ = '\0';
         c = ast_skip_blanks(c);

         if (!strcasecmp(line, "signal")) {
            if (!(event = get_event(c))) {
               break;
            }
         } else if (!strcasecmp(line, "duration")) {
            sscanf(c, "%30u", &duration);
         }
      }
   }

   if (event == '!' || is_flash) {
      struct ast_frame f = { AST_FRAME_CONTROL, { AST_CONTROL_FLASH, } };
      ast_queue_frame(session->channel, &f);
   } else if (event != '\0') {
      struct ast_frame f = { AST_FRAME_DTMF, };
      f.len = duration;
      f.subclass.integer = event;
      ast_queue_frame(session->channel, &f);
   } else {
      ast_log(LOG_ERROR, "Invalid DTMF event signal in INFO message.\n");
   }

   send_response(session, rdata, event ? 200 : 500);
   return 1;
}

static struct ast_sip_session_supplement dtmf_info_supplement = {
   .method = "INFO",
   .priority = AST_SIP_SUPPLEMENT_PRIORITY_FIRST,
   .incoming_request = dtmf_info_incoming_request,
};

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

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

AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP DTMF INFO 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",
);