Emeric Vigier | 2f62582 | 2012-08-06 11:09:52 -0400 | [diff] [blame] | 1 | // Copyright (C) 1999-2005 Open Source Telecom Corporation. |
| 2 | // Copyright (C) 2006-2010 David Sugar, Tycho Softworks. |
| 3 | // |
| 4 | // This program is free software; you can redistribute it and/or modify |
| 5 | // it under the terms of the GNU General Public License as published by |
| 6 | // the Free Software Foundation; either version 2 of the License, or |
| 7 | // (at your option) any later version. |
| 8 | // |
| 9 | // This program is distributed in the hope that it will be useful, |
| 10 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | // GNU General Public License for more details. |
| 13 | // |
| 14 | // You should have received a copy of the GNU General Public License |
| 15 | // along with this program; if not, write to the Free Software |
| 16 | // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 17 | // |
| 18 | // As a special exception, you may use this file as part of a free software |
| 19 | // library without restriction. Specifically, if other files instantiate |
| 20 | // templates or use macros or inline functions from this file, or you compile |
| 21 | // this file and link it with other files to produce an executable, this |
| 22 | // file does not by itself cause the resulting executable to be covered by |
| 23 | // the GNU General Public License. This exception does not however |
| 24 | // invalidate any other reasons why the executable file might be covered by |
| 25 | // the GNU General Public License. |
| 26 | // |
| 27 | // This exception applies only to the code released under the name GNU |
| 28 | // ccRTP. If you copy code from other releases into a copy of GNU |
| 29 | // ccRTP, as the General Public License permits, the exception does |
| 30 | // not apply to the code that you add in this way. To avoid misleading |
| 31 | // anyone as to the status of such modified files, you must delete |
| 32 | // this exception notice from them. |
| 33 | // |
| 34 | // If you write modifications of your own for GNU ccRTP, it is your choice |
| 35 | // whether to permit this exception to apply to your modifications. |
| 36 | // If you do not wish that, delete this exception notice. |
| 37 | // |
| 38 | |
| 39 | /** |
| 40 | * @file rtppkt.cpp |
| 41 | * @short StaticPayloadFormat, DynamicPayloadFormat, RTPPacket, |
| 42 | * OutgoingRTPPkt and IncomingRTPPkt classes implementation. |
| 43 | **/ |
| 44 | |
| 45 | #include "private.h" |
| 46 | #include <ccrtp/rtppkt.h> |
| 47 | #include <ccrtp/CryptoContext.h> |
| 48 | |
| 49 | #ifdef CCXX_NAMESPACES |
| 50 | namespace ost { |
| 51 | #endif |
| 52 | |
| 53 | // Default to 8Khz when no value is specified. |
| 54 | const uint32 PayloadFormat::defaultRTPClockRate = 8000; |
| 55 | |
| 56 | //uint32 PayloadFormat::staticRates[lastStaticPayloadType] |
| 57 | uint32 StaticPayloadFormat::staticAudioTypesRates[] = { |
| 58 | // audio types: |
| 59 | 8000, // 0 - sptPCMU |
| 60 | 0, // 1 - reserved |
| 61 | 8000, // 2 - sptG726_32 |
| 62 | 8000, // 3 - sptGSM |
| 63 | 8000, // 4 - sptG723 |
| 64 | 8000, // 5 - sptDVI4_8000 |
| 65 | 16000, // 6 - sptDVI4_16000 |
| 66 | 8000, // 7 - sptLPC |
| 67 | 8000, // 8 - sptPCMA |
| 68 | 8000, // 9 - sptG722 |
| 69 | 44100, // 10 - sptL16_DUAL |
| 70 | 44100, // 11 - sptL16_MONO |
| 71 | 8000, // 12 - sptQCELP |
| 72 | 0, // 13 - reserved |
| 73 | 90000, // 14 - sptMPA |
| 74 | 8000, // 15 - sptG728 |
| 75 | 11015, // 16 - sptDVI4_11025 |
| 76 | 22050, // 17 - sptDVI4_22050 |
| 77 | 8000 // 18 - sptG729 |
| 78 | /* 0, // reserved |
| 79 | 0, // unassigned |
| 80 | 0, // unassigned |
| 81 | 0, // unassigned |
| 82 | 0 // unassigned |
| 83 | */ |
| 84 | // All video types have 90000 hz RTP clock rate. |
| 85 | // If sometime in the future a static video payload type is |
| 86 | // defined with a different RTP clock rate (quite |
| 87 | // unprobable). This table and/or the StaticPayloadType |
| 88 | // constructor must be changed. |
| 89 | }; |
| 90 | |
| 91 | StaticPayloadFormat::StaticPayloadFormat(StaticPayloadType type) |
| 92 | { |
| 93 | setPayloadType( (type <= lastStaticPayloadType)? type : 0); |
| 94 | if ( type <= sptG729 ) { |
| 95 | // audio static type |
| 96 | setRTPClockRate(staticAudioTypesRates[type]); |
| 97 | } else { |
| 98 | // video static type |
| 99 | setRTPClockRate(90000); |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | DynamicPayloadFormat::DynamicPayloadFormat(PayloadType type, uint32 rate) |
| 104 | { |
| 105 | PayloadFormat::setPayloadType(type); |
| 106 | setRTPClockRate(rate); |
| 107 | } |
| 108 | |
| 109 | // constructor commonly used for incoming packets |
| 110 | RTPPacket::RTPPacket(const unsigned char* const block, size_t len, bool duplicate) : |
| 111 | total((uint32)len), duplicated(duplicate) |
| 112 | { |
| 113 | const RTPFixedHeader* const header = |
| 114 | reinterpret_cast<const RTPFixedHeader*>(block); |
| 115 | hdrSize = sizeof(RTPFixedHeader) + (header->cc << 2); |
| 116 | if ( header->extension ){ |
| 117 | RTPHeaderExt *ext = (RTPHeaderExt *)(block + hdrSize); |
| 118 | hdrSize += sizeof(uint32) + (ntohs(ext->length) * 4); |
| 119 | } |
| 120 | if ( header->padding ) |
| 121 | len -= block[len - 1]; |
| 122 | payloadSize = (uint32)(len - hdrSize); |
| 123 | |
| 124 | if ( duplicate ) { |
| 125 | buffer = new unsigned char[len]; |
| 126 | setbuffer(block,len,0); |
| 127 | } else { |
| 128 | buffer = const_cast<unsigned char*>(block); |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | // constructor commonly used for outgoing packets |
| 133 | RTPPacket::RTPPacket(size_t hdrlen, size_t plen, uint8 paddinglen, CryptoContext* pcc ) : |
| 134 | payloadSize((uint32)plen), buffer(NULL), hdrSize((uint32)hdrlen), |
| 135 | duplicated(false) |
| 136 | { |
| 137 | total = (uint32)(hdrlen + payloadSize); |
| 138 | // compute if there must be padding |
| 139 | uint8 padding = 0; |
| 140 | if ( 0 != paddinglen ) { |
| 141 | padding = paddinglen - (total % paddinglen); |
| 142 | total += padding; |
| 143 | } |
| 144 | srtpLength = 0; |
| 145 | srtpDataOffset = 0; |
| 146 | if (pcc != NULL) { |
| 147 | // compute additional memory for SRTP data |
| 148 | srtpLength = pcc->getTagLength() + pcc->getMkiLength(); |
| 149 | srtpDataOffset = total; // SRTP data go behind header plus payload plus padding |
| 150 | } |
| 151 | |
| 152 | // now we know the actual total length of the packet, get some memory |
| 153 | // but take SRTP data into account. Don't change total because some RTP |
| 154 | // functions rely on the fact that total is the overall size (without |
| 155 | // the SRTP data) |
| 156 | buffer = new unsigned char[total + srtpLength]; |
| 157 | *(reinterpret_cast<uint32*>(getHeader())) = 0; |
| 158 | getHeader()->version = CCRTP_VERSION; |
| 159 | if ( 0 != padding ) { |
| 160 | memset(buffer + total - padding,0,padding - 1); |
| 161 | buffer[total - 1] = padding; |
| 162 | getHeader()->padding = 1; |
| 163 | } else { |
| 164 | getHeader()->padding = 0; |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | void RTPPacket::endPacket() |
| 169 | { |
| 170 | #ifdef CCXX_EXCEPTIONS |
| 171 | try { |
| 172 | #endif |
| 173 | delete [] buffer; |
| 174 | #ifdef CCXX_EXCEPTIONS |
| 175 | } catch (...) { }; |
| 176 | #endif |
| 177 | } |
| 178 | |
| 179 | void RTPPacket::reComputePayLength(bool padding) |
| 180 | { |
| 181 | // If payloadsize was computed without padding set then re-compute |
| 182 | // payloadSize after the padding bit was set and set padding flag |
| 183 | // in RTP header - option for SRTP |
| 184 | if (padding) { |
| 185 | size_t len = 0; |
| 186 | getHeader()->padding = 1; |
| 187 | len -= buffer[payloadSize - 1]; |
| 188 | payloadSize = (uint32)(payloadSize - len); |
| 189 | } |
| 190 | } |
| 191 | |
| 192 | OutgoingRTPPkt::OutgoingRTPPkt(const uint32* const csrcs, uint16 numcsrc, |
| 193 | const unsigned char* const hdrext, uint32 hdrextlen, |
| 194 | const unsigned char* const data, size_t datalen, |
| 195 | uint8 paddinglen, CryptoContext* pcc) : |
| 196 | RTPPacket((getSizeOfFixedHeader() + sizeof(uint32) * numcsrc + hdrextlen),datalen,paddinglen, pcc) |
| 197 | { |
| 198 | uint32 pointer = (uint32)getSizeOfFixedHeader(); |
| 199 | // add CSCR identifiers (putting them in network order). |
| 200 | setCSRCArray(csrcs,numcsrc); |
| 201 | pointer += numcsrc * sizeof(uint32); |
| 202 | |
| 203 | // add header extension. |
| 204 | setbuffer(hdrext,hdrextlen,pointer); |
| 205 | setExtension(hdrextlen > 0); |
| 206 | pointer += hdrextlen; |
| 207 | |
| 208 | // add data. |
| 209 | setbuffer(data,datalen,pointer); |
| 210 | } |
| 211 | |
| 212 | OutgoingRTPPkt::OutgoingRTPPkt(const uint32* const csrcs, uint16 numcsrc, |
| 213 | const unsigned char* data, size_t datalen, uint8 paddinglen, CryptoContext* pcc) : |
| 214 | RTPPacket((getSizeOfFixedHeader() + sizeof(uint32) *numcsrc),datalen, paddinglen, pcc) |
| 215 | { |
| 216 | uint32 pointer = (uint32)getSizeOfFixedHeader(); |
| 217 | // add CSCR identifiers (putting them in network order). |
| 218 | setCSRCArray(csrcs,numcsrc); |
| 219 | pointer += numcsrc * sizeof(uint32); |
| 220 | |
| 221 | // not needed, as the RTPPacket constructor sets by default |
| 222 | // the whole fixed header to 0. |
| 223 | // getHeader()->extension = 0; |
| 224 | |
| 225 | // add data. |
| 226 | setbuffer(data,datalen,pointer); |
| 227 | } |
| 228 | |
| 229 | OutgoingRTPPkt::OutgoingRTPPkt(const unsigned char* data, size_t datalen, |
| 230 | uint8 paddinglen, CryptoContext* pcc) : |
| 231 | RTPPacket(getSizeOfFixedHeader(),datalen,paddinglen, pcc) |
| 232 | { |
| 233 | // not needed, as the RTPPacket constructor sets by default |
| 234 | // the whole fixed header to 0. |
| 235 | //getHeader()->cc = 0; |
| 236 | //getHeader()->extension = 0; |
| 237 | |
| 238 | setbuffer(data,datalen,getSizeOfFixedHeader()); |
| 239 | } |
| 240 | |
| 241 | void OutgoingRTPPkt::setCSRCArray(const uint32* const csrcs, uint16 numcsrc) |
| 242 | { |
| 243 | setbuffer(csrcs, numcsrc * sizeof(uint32),getSizeOfFixedHeader()); |
| 244 | uint32* csrc = const_cast<uint32*>(getCSRCs()); |
| 245 | for ( int i = 0; i < numcsrc; i++ ) |
| 246 | csrc[i] = htonl(csrc[i]); |
| 247 | getHeader()->cc = numcsrc; |
| 248 | } |
| 249 | |
| 250 | void OutgoingRTPPkt::protect(uint32 ssrc, CryptoContext* pcc) |
| 251 | { |
| 252 | /* Encrypt the packet */ |
| 253 | uint64 index = ((uint64)pcc->getRoc() << 16) | (uint64)getSeqNum(); |
| 254 | |
| 255 | pcc->srtpEncrypt(this, index, ssrc); |
| 256 | |
| 257 | // NO MKI support yet - here we assume MKI is zero. To build in MKI |
| 258 | // take MKI length into account when storing the authentication tag. |
| 259 | |
| 260 | /* Compute MAC */ |
| 261 | pcc->srtpAuthenticate(this, pcc->getRoc(), |
| 262 | const_cast<uint8*>(getRawPacket()+srtpDataOffset) ); |
| 263 | /* Update the ROC if necessary */ |
| 264 | if (getSeqNum() == 0xFFFF ) { |
| 265 | pcc->setRoc(pcc->getRoc() + 1); |
| 266 | } |
| 267 | } |
| 268 | |
| 269 | // These masks are valid regardless of endianness. |
| 270 | const uint16 IncomingRTPPkt::RTP_INVALID_PT_MASK = (0x7e); |
| 271 | const uint16 IncomingRTPPkt::RTP_INVALID_PT_VALUE = (0x48); |
| 272 | |
| 273 | IncomingRTPPkt::IncomingRTPPkt(const unsigned char* const block, size_t len) : |
| 274 | RTPPacket(block,len) |
| 275 | { |
| 276 | // first, perform validity check: |
| 277 | // 1) check protocol version |
| 278 | // 2) it is not an SR nor an RR |
| 279 | // 3) consistent length field value (taking CC value and P and |
| 280 | // X bits into account) |
| 281 | if ( getProtocolVersion() != CCRTP_VERSION || (getPayloadType() & RTP_INVALID_PT_MASK) == RTP_INVALID_PT_VALUE) { |
| 282 | /* |
| 283 | || |
| 284 | getPayloadSize() <= 0 ) { |
| 285 | */ |
| 286 | headerValid = false; |
| 287 | return; |
| 288 | } |
| 289 | headerValid = true; |
| 290 | cachedTimestamp = getRawTimestamp(); |
| 291 | cachedSeqNum = ntohs(getHeader()->sequence); |
| 292 | cachedSSRC = ntohl(getHeader()->sources[0]); |
| 293 | } |
| 294 | |
| 295 | int32 IncomingRTPPkt::unprotect(CryptoContext* pcc) |
| 296 | { |
| 297 | if (pcc == NULL) { |
| 298 | return true; |
| 299 | } |
| 300 | |
| 301 | /* |
| 302 | * This is the setting of the packet data when we come to this |
| 303 | * point: |
| 304 | * |
| 305 | * total: complete length of received data |
| 306 | * buffer: points to data as received from network |
| 307 | * hdrSize: length of header including header extension |
| 308 | * payloadSize: length of data excluding hdrSize and padding |
| 309 | * |
| 310 | * Because this is an SRTP packet we need to adjust some values here. |
| 311 | * The SRTP MKI and authentication data is always at the end of a |
| 312 | * packet. Thus compute the position of this data. |
| 313 | */ |
| 314 | |
| 315 | uint32 srtpDataIndex = total - (pcc->getTagLength() + pcc->getMkiLength()); |
| 316 | |
| 317 | // now adjust total because some RTP functions rely on the fact that |
| 318 | // total is the full length of data without SRTP data. |
| 319 | total -= pcc->getTagLength() + pcc->getMkiLength(); |
| 320 | |
| 321 | // recompute payloadSize by subtracting SRTP data |
| 322 | payloadSize -= pcc->getTagLength() + pcc->getMkiLength(); |
| 323 | |
| 324 | // unused?? |
| 325 | // const uint8* mki = getRawPacket() + srtpDataIndex; |
| 326 | const uint8* tag = getRawPacket() + srtpDataIndex + pcc->getMkiLength(); |
| 327 | |
| 328 | /* Replay control */ |
| 329 | if (!pcc->checkReplay(cachedSeqNum)) { |
| 330 | return -2; |
| 331 | } |
| 332 | /* Guess the index */ |
| 333 | uint64 guessedIndex = pcc->guessIndex(cachedSeqNum); |
| 334 | |
| 335 | uint32 guessedRoc = guessedIndex >> 16; |
| 336 | uint8* mac = new uint8[pcc->getTagLength()]; |
| 337 | |
| 338 | pcc->srtpAuthenticate(this, guessedRoc, mac); |
| 339 | if (memcmp(tag, mac, pcc->getTagLength()) != 0) { |
| 340 | delete[] mac; |
| 341 | return -1; |
| 342 | } |
| 343 | delete[] mac; |
| 344 | |
| 345 | /* Decrypt the content */ |
| 346 | pcc->srtpEncrypt( this, guessedIndex, cachedSSRC ); |
| 347 | |
| 348 | /* Update the Crypto-context */ |
| 349 | pcc->update(cachedSeqNum); |
| 350 | |
| 351 | return 1; |
| 352 | } |
| 353 | |
| 354 | #ifdef CCXX_NAMESPACES |
| 355 | } |
| 356 | #endif |
| 357 | |
| 358 | /** EMACS ** |
| 359 | * Local variables: |
| 360 | * mode: c++ |
| 361 | * c-basic-offset: 4 |
| 362 | * End: |
| 363 | */ |