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/*
* libjingle
* Copyright 2011 Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "talk/media/base/rtputils.h"
namespace cricket {
static const int kRtpVersion = 2;
static const size_t kRtpFlagsOffset = 0;
static const size_t kRtpPayloadTypeOffset = 1;
static const size_t kRtpSeqNumOffset = 2;
static const size_t kRtpTimestampOffset = 4;
static const size_t kRtpSsrcOffset = 8;
static const size_t kRtcpPayloadTypeOffset = 1;
bool GetUint8(const void* data, size_t offset, int* value) {
if (!data || !value) {
return false;
}
*value = *(static_cast<const uint8*>(data) + offset);
return true;
}
bool GetUint16(const void* data, size_t offset, int* value) {
if (!data || !value) {
return false;
}
*value = static_cast<int>(
talk_base::GetBE16(static_cast<const uint8*>(data) + offset));
return true;
}
bool GetUint32(const void* data, size_t offset, uint32* value) {
if (!data || !value) {
return false;
}
*value = talk_base::GetBE32(static_cast<const uint8*>(data) + offset);
return true;
}
bool SetUint8(void* data, size_t offset, int value) {
if (!data) {
return false;
}
talk_base::Set8(data, offset, value);
return true;
}
bool SetUint16(void* data, size_t offset, int value) {
if (!data) {
return false;
}
talk_base::SetBE16(static_cast<uint8*>(data) + offset, value);
return true;
}
bool SetUint32(void* data, size_t offset, uint32 value) {
if (!data) {
return false;
}
talk_base::SetBE32(static_cast<uint8*>(data) + offset, value);
return true;
}
bool GetRtpFlags(const void* data, size_t len, int* value) {
if (len < kMinRtpPacketLen) {
return false;
}
return GetUint8(data, kRtpFlagsOffset, value);
}
bool GetRtpPayloadType(const void* data, size_t len, int* value) {
if (len < kMinRtpPacketLen) {
return false;
}
if (!GetUint8(data, kRtpPayloadTypeOffset, value)) {
return false;
}
*value &= 0x7F;
return true;
}
bool GetRtpSeqNum(const void* data, size_t len, int* value) {
if (len < kMinRtpPacketLen) {
return false;
}
return GetUint16(data, kRtpSeqNumOffset, value);
}
bool GetRtpTimestamp(const void* data, size_t len, uint32* value) {
if (len < kMinRtpPacketLen) {
return false;
}
return GetUint32(data, kRtpTimestampOffset, value);
}
bool GetRtpSsrc(const void* data, size_t len, uint32* value) {
if (len < kMinRtpPacketLen) {
return false;
}
return GetUint32(data, kRtpSsrcOffset, value);
}
bool GetRtpHeaderLen(const void* data, size_t len, size_t* value) {
if (!data || len < kMinRtpPacketLen || !value) return false;
const uint8* header = static_cast<const uint8*>(data);
// Get base header size + length of CSRCs (not counting extension yet).
size_t header_size = kMinRtpPacketLen + (header[0] & 0xF) * sizeof(uint32);
if (len < header_size) return false;
// If there's an extension, read and add in the extension size.
if (header[0] & 0x10) {
if (len < header_size + sizeof(uint32)) return false;
header_size += ((talk_base::GetBE16(header + header_size + 2) + 1) *
sizeof(uint32));
if (len < header_size) return false;
}
*value = header_size;
return true;
}
bool GetRtpVersion(const void* data, size_t len, int* version) {
if (len == 0) {
return false;
}
const uint8 first = static_cast<const uint8*>(data)[0];
*version = static_cast<int>((first >> 6) & 0x3);
return true;
}
bool GetRtpHeader(const void* data, size_t len, RtpHeader* header) {
return (GetRtpPayloadType(data, len, &(header->payload_type)) &&
GetRtpSeqNum(data, len, &(header->seq_num)) &&
GetRtpTimestamp(data, len, &(header->timestamp)) &&
GetRtpSsrc(data, len, &(header->ssrc)));
}
bool GetRtcpType(const void* data, size_t len, int* value) {
if (len < kMinRtcpPacketLen) {
return false;
}
return GetUint8(data, kRtcpPayloadTypeOffset, value);
}
// This method returns SSRC first of RTCP packet, except if packet is SDES.
// TODO(mallinath) - Fully implement RFC 5506. This standard doesn't restrict
// to send non-compound packets only to feedback messages.
bool GetRtcpSsrc(const void* data, size_t len, uint32* value) {
// Packet should be at least of 8 bytes, to get SSRC from a RTCP packet.
if (!data || len < kMinRtcpPacketLen + 4 || !value) return false;
int pl_type;
if (!GetRtcpType(data, len, &pl_type)) return false;
// SDES packet parsing is not supported.
if (pl_type == kRtcpTypeSDES) return false;
*value = talk_base::GetBE32(static_cast<const uint8*>(data) + 4);
return true;
}
bool SetRtpHeaderFlags(
void* data, size_t len,
bool padding, bool extension, int csrc_count) {
if (csrc_count > 0x0F) {
return false;
}
int flags = 0;
flags |= (kRtpVersion << 6);
flags |= ((padding ? 1 : 0) << 5);
flags |= ((extension ? 1 : 0) << 4);
flags |= csrc_count;
return SetUint8(data, kRtpFlagsOffset, flags);
}
// Assumes marker bit is 0.
bool SetRtpPayloadType(void* data, size_t len, int value) {
if (value >= 0x7F) {
return false;
}
return SetUint8(data, kRtpPayloadTypeOffset, value & 0x7F);
}
bool SetRtpSeqNum(void* data, size_t len, int value) {
return SetUint16(data, kRtpSeqNumOffset, value);
}
bool SetRtpTimestamp(void* data, size_t len, uint32 value) {
return SetUint32(data, kRtpTimestampOffset, value);
}
bool SetRtpSsrc(void* data, size_t len, uint32 value) {
return SetUint32(data, kRtpSsrcOffset, value);
}
// Assumes version 2, no padding, no extensions, no csrcs.
bool SetRtpHeader(void* data, size_t len, const RtpHeader& header) {
return (SetRtpHeaderFlags(data, len, false, false, 0) &&
SetRtpPayloadType(data, len, header.payload_type) &&
SetRtpSeqNum(data, len, header.seq_num) &&
SetRtpTimestamp(data, len, header.timestamp) &&
SetRtpSsrc(data, len, header.ssrc));
}
} // namespace cricket
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