session.c

一个开源SIP协议栈

/* $Id: session.c 1107 2007-03-27 10:53:57Z bennylp $ */
/* 
 * Copyright (C) 2003-2007 Benny Prijono <[e-mail]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
#include <pjmedia/session.h>
#include <pjmedia/errno.h>
#include <pj/log.h>
#include <pj/os.h> 
#include <pj/pool.h>
#include <pj/string.h>
#include <pj/assert.h>
#include <pj/ctype.h>
#include <pj/rand.h>


struct pjmedia_session
{
    pj_pool_t		   *pool;
    pjmedia_endpt	   *endpt;
    unsigned		    stream_cnt;
    pjmedia_stream_info	    stream_info[PJMEDIA_MAX_SDP_MEDIA];
    pjmedia_stream	   *stream[PJMEDIA_MAX_SDP_MEDIA];
    void		   *user_data;
};

#define THIS_FILE		"session.c"

#define PJMEDIA_SESSION_SIZE	(48*1024)
#define PJMEDIA_SESSION_INC	1024

static const pj_str_t ID_AUDIO = { "audio", 5};
static const pj_str_t ID_VIDEO = { "video", 5};
static const pj_str_t ID_IN = { "IN", 2 };
static const pj_str_t ID_IP4 = { "IP4", 3};
static const pj_str_t ID_RTP_AVP = { "RTP/AVP", 7 };
static const pj_str_t ID_SDP_NAME = { "pjmedia", 7 };
static const pj_str_t ID_RTPMAP = { "rtpmap", 6 };
static const pj_str_t ID_TELEPHONE_EVENT = { "telephone-event", 15 };

static const pj_str_t STR_INACTIVE = { "inactive", 8 };
static const pj_str_t STR_SENDRECV = { "sendrecv", 8 };
static const pj_str_t STR_SENDONLY = { "sendonly", 8 };
static const pj_str_t STR_RECVONLY = { "recvonly", 8 };


/*
 * Get fmtp mode parameter associated with the codec.
 */
static pj_status_t get_fmtp_mode(const pjmedia_sdp_media *m,
				 const pj_str_t *fmt,
				 int *p_mode)
{
    const pjmedia_sdp_attr *attr;
    pjmedia_sdp_fmtp fmtp;
    const pj_str_t str_mode = { "mode=", 5 };
    char *pos;

    /* Get "fmtp" attribute for the format */
    attr = pjmedia_sdp_media_find_attr2(m, "fmtp", fmt);
    if (attr == NULL)
	return -1;

    /* Parse "fmtp" attribute */
    if (pjmedia_sdp_attr_get_fmtp(attr, &fmtp) != PJ_SUCCESS)
	return -1;

    /* Look for "mode=" string in the fmtp */
    while (fmtp.fmt_param.slen >= str_mode.slen + 1) {
	if (pj_strnicmp(&fmtp.fmt_param, &str_mode, str_mode.slen)==0) {
	    /* Found "mode=" string */
	    break;
	}

	fmtp.fmt_param.ptr++;
	fmtp.fmt_param.slen--;
    }

    if (fmtp.fmt_param.slen < str_mode.slen + 1) {
	/* "mode=" param not found */
	return -1;
    }

    /* Get the mode */
    pos = fmtp.fmt_param.ptr + str_mode.slen;
    *p_mode = 0;
    while (pj_isdigit(*pos)) {
	*p_mode = *p_mode * 10 + (*pos - '0');
	++pos;
    }

    return PJ_SUCCESS;
}


/*
 * Create stream info from SDP media line.
 */
PJ_DEF(pj_status_t) pjmedia_stream_info_from_sdp(
					   pjmedia_stream_info *si,
					   pj_pool_t *pool,
					   pjmedia_endpt *endpt,
					   const pjmedia_sdp_session *local,
					   const pjmedia_sdp_session *remote,
					   unsigned stream_idx)
{
    pjmedia_codec_mgr *mgr;
    const pjmedia_sdp_attr *attr;
    const pjmedia_sdp_media *local_m;
    const pjmedia_sdp_media *rem_m;
    const pjmedia_sdp_conn *local_conn;
    const pjmedia_sdp_conn *rem_conn;
    pjmedia_sdp_rtpmap *rtpmap;
    int local_fmtp_mode = 0, rem_fmtp_mode = 0;
    unsigned i, pt, fmti;
    pj_status_t status;

    
    /* Validate arguments: */
    PJ_ASSERT_RETURN(pool && si && local && remote, PJ_EINVAL);
    PJ_ASSERT_RETURN(stream_idx < local->media_count, PJ_EINVAL);
    PJ_ASSERT_RETURN(stream_idx < remote->media_count, PJ_EINVAL);


    /* Get codec manager. */
    mgr = pjmedia_endpt_get_codec_mgr(endpt);

    /* Keep SDP shortcuts */
    local_m = local->media[stream_idx];
    rem_m = remote->media[stream_idx];

    local_conn = local_m->conn ? local_m->conn : local->conn;
    if (local_conn == NULL)
	return PJMEDIA_SDP_EMISSINGCONN;

    rem_conn = rem_m->conn ? rem_m->conn : remote->conn;
    if (rem_conn == NULL)
	return PJMEDIA_SDP_EMISSINGCONN;


    /* Reset: */

    pj_bzero(si, sizeof(*si));

    /* Media type: */

    if (pj_stricmp(&local_m->desc.media, &ID_AUDIO) == 0) {

	si->type = PJMEDIA_TYPE_AUDIO;

    } else if (pj_stricmp(&local_m->desc.media, &ID_VIDEO) == 0) {

	si->type = PJMEDIA_TYPE_VIDEO;

    } else {

	si->type = PJMEDIA_TYPE_UNKNOWN;
	return PJMEDIA_EINVALIMEDIATYPE;
    }

    /* Transport type must be equal */
    if (pj_stricmp(&rem_m->desc.transport, 
		   &local_m->desc.transport) != 0) 
    {
	si->type = PJMEDIA_TYPE_UNKNOWN;
	return PJMEDIA_SDPNEG_EINVANSTP;
    }

    /* Media direction: */

    if (local_m->desc.port == 0 || 
	pj_inet_addr(&local_conn->addr).s_addr==0 ||
	pj_inet_addr(&rem_conn->addr).s_addr==0 ||
	pjmedia_sdp_media_find_attr(local_m, &STR_INACTIVE, NULL)!=NULL)
    {
	/* Inactive stream. */

	si->dir = PJMEDIA_DIR_NONE;

    } else if (pjmedia_sdp_media_find_attr(local_m, &STR_SENDONLY, NULL)!=NULL) {

	/* Send only stream. */

	si->dir = PJMEDIA_DIR_ENCODING;

    } else if (pjmedia_sdp_media_find_attr(local_m, &STR_RECVONLY, NULL)!=NULL) {

	/* Recv only stream. */

	si->dir = PJMEDIA_DIR_DECODING;

    } else {

	/* Send and receive stream. */

	si->dir = PJMEDIA_DIR_ENCODING_DECODING;

    }


    /* Set remote address: */
    status = pj_sockaddr_in_init(&si->rem_addr, &rem_conn->addr, 
				 rem_m->desc.port);
    if (status != PJ_SUCCESS) {
	/* Invalid IP address. */
	return PJMEDIA_EINVALIDIP;
    }

    /* If "rtcp" attribute is present in the SDP, set the RTCP address
     * from that attribute. Otherwise, calculate from RTP address.
     */
    attr = pjmedia_sdp_attr_find2(rem_m->attr_count, rem_m->attr,
				  "rtcp", NULL);
    if (attr) {
	pjmedia_sdp_rtcp_attr rtcp;
	status = pjmedia_sdp_attr_get_rtcp(attr, &rtcp);
	if (status == PJ_SUCCESS) {
	    if (rtcp.addr.slen) {
		status = pj_sockaddr_in_init(&si->rem_rtcp, &rtcp.addr,
					     (pj_uint16_t)rtcp.port);
	    } else {
		pj_sockaddr_in_init(&si->rem_rtcp, NULL, 
				    (pj_uint16_t)rtcp.port);
		si->rem_rtcp.sin_addr.s_addr = si->rem_addr.sin_addr.s_addr;
	    }
	}
    }
    
    if (si->rem_rtcp.sin_addr.s_addr == 0) {
	int rtcp_port;

	pj_memcpy(&si->rem_rtcp, &si->rem_addr, sizeof(pj_sockaddr_in));
	rtcp_port = pj_ntohs(si->rem_addr.sin_port) + 1;
	si->rem_rtcp.sin_port = pj_htons((pj_uint16_t)rtcp_port);
    }


    /* Get the payload number for receive channel. */
    /*
       Previously we used to rely on fmt[0] being the selected codec,
       but some UA sends telephone-event as fmt[0] and this would
       cause assert failure below.

       Thanks Chris Hamilton <chamilton .at. cs.dal.ca> for this patch.

    // And codec must be numeric!
    if (!pj_isdigit(*local_m->desc.fmt[0].ptr) || 
	!pj_isdigit(*rem_m->desc.fmt[0].ptr))
    {
	return PJMEDIA_EINVALIDPT;
    }

    pt = pj_strtoul(&local_m->desc.fmt[0]);
    pj_assert(PJMEDIA_RTP_PT_TELEPHONE_EVENTS==0 ||
	      pt != PJMEDIA_RTP_PT_TELEPHONE_EVENTS);
    */

    /* This is to suppress MSVC warning about uninitialized var */
    pt = 0;

    /* Find the first codec which is not telephone-event */
    for ( fmti = 0; fmti < local_m->desc.fmt_count; ++fmti ) {
	if ( !pj_isdigit(*local_m->desc.fmt[fmti].ptr) )
	    return PJMEDIA_EINVALIDPT;
	pt = pj_strtoul(&local_m->desc.fmt[fmti]);
	if ( PJMEDIA_RTP_PT_TELEPHONE_EVENTS == 0 ||
		pt != PJMEDIA_RTP_PT_TELEPHONE_EVENTS )
		break;
    }
    if ( fmti >= local_m->desc.fmt_count )
	return PJMEDIA_EINVALIDPT;

    /* Get codec info.
     * For static payload types, get the info from codec manager.
     * For dynamic payload types, MUST get the rtpmap.
     */
    if (pt < 96) {
	pj_bool_t has_rtpmap;

	rtpmap = NULL;
	has_rtpmap = PJ_TRUE;

	attr = pjmedia_sdp_media_find_attr(local_m, &ID_RTPMAP, 
					   &local_m->desc.fmt[fmti]);
	if (attr == NULL) {
	    has_rtpmap = PJ_FALSE;
	}
	if (attr != NULL) {
	    status = pjmedia_sdp_attr_to_rtpmap(pool, attr, &rtpmap);
	    if (status != PJ_SUCCESS)
		has_rtpmap = PJ_FALSE;
	}

	/* Build codec format info: */
	if (has_rtpmap) {
	    si->fmt.type = si->type;
	    si->fmt.pt = pj_strtoul(&local_m->desc.fmt[fmti]);
	    pj_strdup(pool, &si->fmt.encoding_name, &rtpmap->enc_name);
	    si->fmt.clock_rate = rtpmap->clock_rate;
	    
	    /* For audio codecs, rtpmap parameters denotes the number of
	     * channels.
	     */
	    if (si->type == PJMEDIA_TYPE_AUDIO && rtpmap->param.slen) {
		
		if (rtpmap->param.slen == 2) {
		    si->fmt.channel_cnt = rtpmap->param.ptr[1] - '0';
		} else {
		    pj_str_t cnt;
		    cnt.ptr = rtpmap->param.ptr + 1;
		    cnt.slen = rtpmap->param.slen - 1;
		    si->fmt.channel_cnt = (unsigned) pj_strtoul(&cnt);
		}

	    } else {
		si->fmt.channel_cnt = 1;
	    }

	} else {	    
	    const pjmedia_codec_info *p_info;

	    status = pjmedia_codec_mgr_get_codec_info( mgr, pt, &p_info);
	    if (status != PJ_SUCCESS)
		return status;

	    pj_memcpy(&si->fmt, p_info, sizeof(pjmedia_codec_info));
	}

	/* For static payload type, pt's are symetric */
	si->tx_pt = pt;

    } else {

	attr = pjmedia_sdp_media_find_attr(local_m, &ID_RTPMAP, 
					   &local_m->desc.fmt[fmti]);
	if (attr == NULL)
	    return PJMEDIA_EMISSINGRTPMAP;

	status = pjmedia_sdp_attr_to_rtpmap(pool, attr, &rtpmap);
	if (status != PJ_SUCCESS)
	    return status;

	/* Build codec format info: */

	si->fmt.type = si->type;
	si->fmt.pt = pj_strtoul(&local_m->desc.fmt[fmti]);
	pj_strdup(pool, &si->fmt.encoding_name, &rtpmap->enc_name);
	si->fmt.clock_rate = rtpmap->clock_rate;

	/* For audio codecs, rtpmap parameters denotes the number of
	 * channels.
	 */
	if (si->type == PJMEDIA_TYPE_AUDIO && rtpmap->param.slen) {
	    
	    if (rtpmap->param.slen == 2) {
		si->fmt.channel_cnt = rtpmap->param.ptr[1] - '0';
	    } else {
		pj_str_t cnt;
		cnt.ptr = rtpmap->param.ptr + 1;
		cnt.slen = rtpmap->param.slen - 1;
		si->fmt.channel_cnt = (unsigned) pj_strtoul(&cnt);
	    }

	} else {
	    si->fmt.channel_cnt = 1;
	}

	/* Get fmtp mode= param in local SDP, if any */
	get_fmtp_mode(local_m, &local_m->desc.fmt[fmti], &local_fmtp_mode);

	/* Determine payload type for outgoing channel, by finding
	 * dynamic payload type in remote SDP that matches the answer.
	 */
	si->tx_pt = 0xFFFF;
	for (i=0; i<rem_m->desc.fmt_count; ++i) {