res_pjsip_dtmf_info.c

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/*
 * 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",
);