rtp_util.cc (1955B)
1 /* 2 * Copyright (c) 2021 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #include "modules/rtp_rtcp/source/rtp_util.h" 12 13 #include <cstddef> 14 #include <cstdint> 15 16 #include "api/array_view.h" 17 #include "modules/rtp_rtcp/source/byte_io.h" 18 #include "rtc_base/checks.h" 19 20 namespace webrtc { 21 namespace { 22 23 constexpr uint8_t kRtpVersion = 2; 24 constexpr size_t kMinRtpPacketLen = 12; 25 constexpr size_t kMinRtcpPacketLen = 4; 26 27 bool HasCorrectRtpVersion(ArrayView<const uint8_t> packet) { 28 return packet[0] >> 6 == kRtpVersion; 29 } 30 31 // For additional details, see http://tools.ietf.org/html/rfc5761#section-4 32 bool PayloadTypeIsReservedForRtcp(uint8_t payload_type) { 33 return 64 <= payload_type && payload_type < 96; 34 } 35 36 } // namespace 37 38 bool IsRtpPacket(ArrayView<const uint8_t> packet) { 39 return packet.size() >= kMinRtpPacketLen && HasCorrectRtpVersion(packet) && 40 !PayloadTypeIsReservedForRtcp(packet[1] & 0x7F); 41 } 42 43 bool IsRtcpPacket(ArrayView<const uint8_t> packet) { 44 return packet.size() >= kMinRtcpPacketLen && HasCorrectRtpVersion(packet) && 45 PayloadTypeIsReservedForRtcp(packet[1] & 0x7F); 46 } 47 48 int ParseRtpPayloadType(ArrayView<const uint8_t> rtp_packet) { 49 RTC_DCHECK(IsRtpPacket(rtp_packet)); 50 return rtp_packet[1] & 0x7F; 51 } 52 53 uint16_t ParseRtpSequenceNumber(ArrayView<const uint8_t> rtp_packet) { 54 RTC_DCHECK(IsRtpPacket(rtp_packet)); 55 return ByteReader<uint16_t>::ReadBigEndian(rtp_packet.data() + 2); 56 } 57 58 uint32_t ParseRtpSsrc(ArrayView<const uint8_t> rtp_packet) { 59 RTC_DCHECK(IsRtpPacket(rtp_packet)); 60 return ByteReader<uint32_t>::ReadBigEndian(rtp_packet.data() + 8); 61 } 62 63 } // namespace webrtc