1 /* 2 * libjingle 3 * Copyright 2011 Google Inc. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "talk/media/base/rtputils.h" 29 30 namespace cricket { 31 32 static const int kRtpVersion = 2; 33 static const size_t kRtpFlagsOffset = 0; 34 static const size_t kRtpPayloadTypeOffset = 1; 35 static const size_t kRtpSeqNumOffset = 2; 36 static const size_t kRtpTimestampOffset = 4; 37 static const size_t kRtpSsrcOffset = 8; 38 static const size_t kRtcpPayloadTypeOffset = 1; 39 40 bool GetUint8(const void* data, size_t offset, int* value) { 41 if (!data || !value) { 42 return false; 43 } 44 *value = *(static_cast<const uint8*>(data) + offset); 45 return true; 46 } 47 48 bool GetUint16(const void* data, size_t offset, int* value) { 49 if (!data || !value) { 50 return false; 51 } 52 *value = static_cast<int>( 53 rtc::GetBE16(static_cast<const uint8*>(data) + offset)); 54 return true; 55 } 56 57 bool GetUint32(const void* data, size_t offset, uint32* value) { 58 if (!data || !value) { 59 return false; 60 } 61 *value = rtc::GetBE32(static_cast<const uint8*>(data) + offset); 62 return true; 63 } 64 65 bool SetUint8(void* data, size_t offset, int value) { 66 if (!data) { 67 return false; 68 } 69 rtc::Set8(data, offset, value); 70 return true; 71 } 72 73 bool SetUint16(void* data, size_t offset, int value) { 74 if (!data) { 75 return false; 76 } 77 rtc::SetBE16(static_cast<uint8*>(data) + offset, value); 78 return true; 79 } 80 81 bool SetUint32(void* data, size_t offset, uint32 value) { 82 if (!data) { 83 return false; 84 } 85 rtc::SetBE32(static_cast<uint8*>(data) + offset, value); 86 return true; 87 } 88 89 bool GetRtpFlags(const void* data, size_t len, int* value) { 90 if (len < kMinRtpPacketLen) { 91 return false; 92 } 93 return GetUint8(data, kRtpFlagsOffset, value); 94 } 95 96 bool GetRtpPayloadType(const void* data, size_t len, int* value) { 97 if (len < kMinRtpPacketLen) { 98 return false; 99 } 100 if (!GetUint8(data, kRtpPayloadTypeOffset, value)) { 101 return false; 102 } 103 *value &= 0x7F; 104 return true; 105 } 106 107 bool GetRtpSeqNum(const void* data, size_t len, int* value) { 108 if (len < kMinRtpPacketLen) { 109 return false; 110 } 111 return GetUint16(data, kRtpSeqNumOffset, value); 112 } 113 114 bool GetRtpTimestamp(const void* data, size_t len, uint32* value) { 115 if (len < kMinRtpPacketLen) { 116 return false; 117 } 118 return GetUint32(data, kRtpTimestampOffset, value); 119 } 120 121 bool GetRtpSsrc(const void* data, size_t len, uint32* value) { 122 if (len < kMinRtpPacketLen) { 123 return false; 124 } 125 return GetUint32(data, kRtpSsrcOffset, value); 126 } 127 128 bool GetRtpHeaderLen(const void* data, size_t len, size_t* value) { 129 if (!data || len < kMinRtpPacketLen || !value) return false; 130 const uint8* header = static_cast<const uint8*>(data); 131 // Get base header size + length of CSRCs (not counting extension yet). 132 size_t header_size = kMinRtpPacketLen + (header[0] & 0xF) * sizeof(uint32); 133 if (len < header_size) return false; 134 // If there's an extension, read and add in the extension size. 135 if (header[0] & 0x10) { 136 if (len < header_size + sizeof(uint32)) return false; 137 header_size += ((rtc::GetBE16(header + header_size + 2) + 1) * 138 sizeof(uint32)); 139 if (len < header_size) return false; 140 } 141 *value = header_size; 142 return true; 143 } 144 145 bool GetRtpVersion(const void* data, size_t len, int* version) { 146 if (len == 0) { 147 return false; 148 } 149 150 const uint8 first = static_cast<const uint8*>(data)[0]; 151 *version = static_cast<int>((first >> 6) & 0x3); 152 return true; 153 } 154 155 bool GetRtpHeader(const void* data, size_t len, RtpHeader* header) { 156 return (GetRtpPayloadType(data, len, &(header->payload_type)) && 157 GetRtpSeqNum(data, len, &(header->seq_num)) && 158 GetRtpTimestamp(data, len, &(header->timestamp)) && 159 GetRtpSsrc(data, len, &(header->ssrc))); 160 } 161 162 bool GetRtcpType(const void* data, size_t len, int* value) { 163 if (len < kMinRtcpPacketLen) { 164 return false; 165 } 166 return GetUint8(data, kRtcpPayloadTypeOffset, value); 167 } 168 169 // This method returns SSRC first of RTCP packet, except if packet is SDES. 170 // TODO(mallinath) - Fully implement RFC 5506. This standard doesn't restrict 171 // to send non-compound packets only to feedback messages. 172 bool GetRtcpSsrc(const void* data, size_t len, uint32* value) { 173 // Packet should be at least of 8 bytes, to get SSRC from a RTCP packet. 174 if (!data || len < kMinRtcpPacketLen + 4 || !value) return false; 175 int pl_type; 176 if (!GetRtcpType(data, len, &pl_type)) return false; 177 // SDES packet parsing is not supported. 178 if (pl_type == kRtcpTypeSDES) return false; 179 *value = rtc::GetBE32(static_cast<const uint8*>(data) + 4); 180 return true; 181 } 182 183 bool SetRtpHeaderFlags( 184 void* data, size_t len, 185 bool padding, bool extension, int csrc_count) { 186 if (csrc_count > 0x0F) { 187 return false; 188 } 189 int flags = 0; 190 flags |= (kRtpVersion << 6); 191 flags |= ((padding ? 1 : 0) << 5); 192 flags |= ((extension ? 1 : 0) << 4); 193 flags |= csrc_count; 194 return SetUint8(data, kRtpFlagsOffset, flags); 195 } 196 197 // Assumes marker bit is 0. 198 bool SetRtpPayloadType(void* data, size_t len, int value) { 199 if (value >= 0x7F) { 200 return false; 201 } 202 return SetUint8(data, kRtpPayloadTypeOffset, value & 0x7F); 203 } 204 205 bool SetRtpSeqNum(void* data, size_t len, int value) { 206 return SetUint16(data, kRtpSeqNumOffset, value); 207 } 208 209 bool SetRtpTimestamp(void* data, size_t len, uint32 value) { 210 return SetUint32(data, kRtpTimestampOffset, value); 211 } 212 213 bool SetRtpSsrc(void* data, size_t len, uint32 value) { 214 return SetUint32(data, kRtpSsrcOffset, value); 215 } 216 217 // Assumes version 2, no padding, no extensions, no csrcs. 218 bool SetRtpHeader(void* data, size_t len, const RtpHeader& header) { 219 return (SetRtpHeaderFlags(data, len, false, false, 0) && 220 SetRtpPayloadType(data, len, header.payload_type) && 221 SetRtpSeqNum(data, len, header.seq_num) && 222 SetRtpTimestamp(data, len, header.timestamp) && 223 SetRtpSsrc(data, len, header.ssrc)); 224 } 225 226 bool IsRtpPacket(const void* data, size_t len) { 227 if (len < kMinRtpPacketLen) 228 return false; 229 230 int version = 0; 231 if (!GetRtpVersion(data, len, &version)) 232 return false; 233 234 return version == kRtpVersion; 235 } 236 237 } // namespace cricket 238
