sems/core/AmRtpPacket.cpp

/*
 * Copyright (C) 2002-2003 Fhg Fokus
 *
 * This file is part of SEMS, a free SIP media server.
 *
 * SEMS 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 released under
 * the GPL with the additional exemption that compiling, linking,
 * and/or using OpenSSL is allowed.
 *
 * For a license to use the SEMS software under conditions
 * other than those described here, or to purchase support for this
 * software, please contact iptel.org by e-mail at the following addresses:
 *    info@iptel.org
 *
 * SEMS 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
 */

#define __APPLE_USE_RFC_3542
#include <netinet/in.h>

#include "AmRtpPacket.h"
#include "rtp/rtp.h"
#include "log.h"
#include "AmConfig.h"

#include "sip/raw_sender.h"
#include "sip/ip_util.h"

#include <assert.h>
#include <string.h>
#include <errno.h>

#include <sys/socket.h>
#include <arpa/inet.h>

#include "sip/msg_logger.h"

AmRtpPacket::AmRtpPacket()
  : data_offset(0)
{
  // buffer will be overwritten by received packet 
  // of hdr+data - does not need to be set to 0s
  //    memset(buffer,0,4096);
}

AmRtpPacket::~AmRtpPacket()
{
}

int AmRtpPacket::parse()
{
  assert(buffer);
  assert(b_size);

  rtp_hdr_t* hdr = (rtp_hdr_t*)buffer;
  // ZRTP "Hello" packet has version == 0
  if ((hdr->version != RTP_VERSION) && (hdr->version != 0))
      {
	DBG("received RTP packet with unsupported version (%i).\n",
	    hdr->version);
	return -1;
      }

  data_offset = sizeof(rtp_hdr_t) + (hdr->cc*4);

  if(hdr->x != 0) {
    //#ifndef WITH_ZRTP 
    //if (AmConfig::IgnoreRTPXHdrs) {
    //  skip the extension header
    //#endif
    if (b_size >= data_offset + 4) {
      data_offset +=
	ntohs(((rtp_xhdr_t*) (buffer + data_offset))->len)*4;
    }
    // #ifndef WITH_ZRTP
    //   } else {
    //     DBG("RTP extension headers not supported.\n");
    //     return -1;
    //   }
    // #endif
  }

  payload = hdr->pt;
  marker = hdr->m;
  sequence = ntohs(hdr->seq);
  timestamp = ntohl(hdr->ts);
  ssrc = ntohl(hdr->ssrc);
  version = hdr->version;

  if (data_offset > b_size) {
    ERROR("bad rtp packet (hdr-size=%u;pkt-size=%u) !\n",
	  data_offset,b_size);
    return -1;
  }
  d_size = b_size - data_offset;

  if(hdr->p){
    if (buffer[b_size-1]>=d_size){
      ERROR("bad rtp packet (invalid padding size) !\n");
      return -1;
    }
    d_size -= buffer[b_size-1];
  }

  return 0;
}

unsigned char *AmRtpPacket::getData()
{
  return &buffer[data_offset];
}

unsigned char *AmRtpPacket::getBuffer()
{
  return &buffer[0];
}

int AmRtpPacket::compile(unsigned char* data_buf, unsigned int size)
{
  assert(data_buf);
  assert(size);

  d_size = size;
  b_size = d_size + sizeof(rtp_hdr_t);
  assert(b_size <= 4096);
  rtp_hdr_t* hdr = (rtp_hdr_t*)buffer;

  if(b_size>sizeof(buffer)){
    ERROR("builtin buffer size (%d) exceeded: %d\n",
	  (int)sizeof(buffer), b_size);
    return -1;
  }

  memset(hdr,0,sizeof(rtp_hdr_t));
  hdr->version = RTP_VERSION;
  hdr->m = marker;
  hdr->pt = payload;
    
  hdr->seq = htons(sequence);
  hdr->ts = htonl(timestamp);
  hdr->ssrc = htonl(ssrc);
    
  data_offset = sizeof(rtp_hdr_t);
  memcpy(&buffer[data_offset],data_buf,d_size);

  return 0;
}

int AmRtpPacket::compile_raw(unsigned char* data_buf, unsigned int size)
{
  if ((!size) || (!data_buf))
    return -1;

  if(size>sizeof(buffer)){
    ERROR("builtin buffer size (%d) exceeded: %d\n",
	  (int)sizeof(buffer), size);
    return -1;
  }

  memcpy(&buffer[0], data_buf, size);
  b_size = size;

  return size;
}

/*
 * RFC5761 Section 4
 * Get the RTCP packet type
 * Assume RTP if type is 0-63 or 96-127.
 */
bool AmRtpPacket::isPacketRtcp(unsigned char *buffer, size_t len)
{
  int type = (len >= 2) ? (buffer[1] & 0x7F) : 0;
  return (type >= 64 && type < 96);
}

bool AmRtpPacket::isPacketRtp(unsigned char* buffer, size_t len) {
  return len >= sizeof(rtp_hdr_t) && ((rtp_hdr_t*)buffer)->version == 2;
}