res_pjsip_dtmf_info.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * Jason Parker <jparker@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"
 
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)
{
    static const pj_str_t STR_INFO = { "INFO", 4 };
 
    if (pjsip_endpt_add_capability(ast_sip_get_pjsip_endpoint(),
            NULL, PJSIP_H_ALLOW, NULL, 1, &STR_INFO) != PJ_SUCCESS) {
        return AST_MODULE_LOAD_DECLINE;
    }
 
    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",
);