| // Copyright (C) 1999-2005 Open Source Telecom Corporation. |
| // Copyright (C) 2006-2010 David Sugar, Tycho Softworks. |
| // |
| // This program 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 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. |
| // |
| // As a special exception, you may use this file as part of a free software |
| // library without restriction. Specifically, if other files instantiate |
| // templates or use macros or inline functions from this file, or you compile |
| // this file and link it with other files to produce an executable, this |
| // file does not by itself cause the resulting executable to be covered by |
| // the GNU General Public License. This exception does not however |
| // invalidate any other reasons why the executable file might be covered by |
| // the GNU General Public License. |
| // |
| // This exception applies only to the code released under the name GNU |
| // ccRTP. If you copy code from other releases into a copy of GNU |
| // ccRTP, as the General Public License permits, the exception does |
| // not apply to the code that you add in this way. To avoid misleading |
| // anyone as to the status of such modified files, you must delete |
| // this exception notice from them. |
| // |
| // If you write modifications of your own for GNU ccRTP, it is your choice |
| // whether to permit this exception to apply to your modifications. |
| // If you do not wish that, delete this exception notice. |
| // |
| |
| /** |
| * @file rtppkt.cpp |
| * @short StaticPayloadFormat, DynamicPayloadFormat, RTPPacket, |
| * OutgoingRTPPkt and IncomingRTPPkt classes implementation. |
| **/ |
| |
| #include "private.h" |
| #include <ccrtp/rtppkt.h> |
| #include <ccrtp/CryptoContext.h> |
| |
| #ifdef CCXX_NAMESPACES |
| namespace ost { |
| #endif |
| |
| // Default to 8Khz when no value is specified. |
| const uint32 PayloadFormat::defaultRTPClockRate = 8000; |
| |
| //uint32 PayloadFormat::staticRates[lastStaticPayloadType] |
| uint32 StaticPayloadFormat::staticAudioTypesRates[] = { |
| // audio types: |
| 8000, // 0 - sptPCMU |
| 0, // 1 - reserved |
| 8000, // 2 - sptG726_32 |
| 8000, // 3 - sptGSM |
| 8000, // 4 - sptG723 |
| 8000, // 5 - sptDVI4_8000 |
| 16000, // 6 - sptDVI4_16000 |
| 8000, // 7 - sptLPC |
| 8000, // 8 - sptPCMA |
| 8000, // 9 - sptG722 |
| 44100, // 10 - sptL16_DUAL |
| 44100, // 11 - sptL16_MONO |
| 8000, // 12 - sptQCELP |
| 0, // 13 - reserved |
| 90000, // 14 - sptMPA |
| 8000, // 15 - sptG728 |
| 11015, // 16 - sptDVI4_11025 |
| 22050, // 17 - sptDVI4_22050 |
| 8000 // 18 - sptG729 |
| /* 0, // reserved |
| 0, // unassigned |
| 0, // unassigned |
| 0, // unassigned |
| 0 // unassigned |
| */ |
| // All video types have 90000 hz RTP clock rate. |
| // If sometime in the future a static video payload type is |
| // defined with a different RTP clock rate (quite |
| // unprobable). This table and/or the StaticPayloadType |
| // constructor must be changed. |
| }; |
| |
| StaticPayloadFormat::StaticPayloadFormat(StaticPayloadType type) |
| { |
| setPayloadType( (type <= lastStaticPayloadType)? type : 0); |
| if ( type <= sptG729 ) { |
| // audio static type |
| setRTPClockRate(staticAudioTypesRates[type]); |
| } else { |
| // video static type |
| setRTPClockRate(90000); |
| } |
| } |
| |
| DynamicPayloadFormat::DynamicPayloadFormat(PayloadType type, uint32 rate) |
| { |
| PayloadFormat::setPayloadType(type); |
| setRTPClockRate(rate); |
| } |
| |
| // constructor commonly used for incoming packets |
| RTPPacket::RTPPacket(const unsigned char* const block, size_t len, bool duplicate) : |
| total((uint32)len), duplicated(duplicate) |
| { |
| const RTPFixedHeader* const header = |
| reinterpret_cast<const RTPFixedHeader*>(block); |
| hdrSize = sizeof(RTPFixedHeader) + (header->cc << 2); |
| if ( header->extension ){ |
| RTPHeaderExt *ext = (RTPHeaderExt *)(block + hdrSize); |
| hdrSize += sizeof(uint32) + (ntohs(ext->length) * 4); |
| } |
| if ( header->padding ) |
| len -= block[len - 1]; |
| payloadSize = (uint32)(len - hdrSize); |
| |
| if ( duplicate ) { |
| buffer = new unsigned char[len]; |
| setbuffer(block,len,0); |
| } else { |
| buffer = const_cast<unsigned char*>(block); |
| } |
| } |
| |
| // constructor commonly used for outgoing packets |
| RTPPacket::RTPPacket(size_t hdrlen, size_t plen, uint8 paddinglen, CryptoContext* pcc ) : |
| payloadSize((uint32)plen), buffer(NULL), hdrSize((uint32)hdrlen), |
| duplicated(false) |
| { |
| total = (uint32)(hdrlen + payloadSize); |
| // compute if there must be padding |
| uint8 padding = 0; |
| if ( 0 != paddinglen ) { |
| padding = paddinglen - (total % paddinglen); |
| total += padding; |
| } |
| srtpLength = 0; |
| srtpDataOffset = 0; |
| if (pcc != NULL) { |
| // compute additional memory for SRTP data |
| srtpLength = pcc->getTagLength() + pcc->getMkiLength(); |
| srtpDataOffset = total; // SRTP data go behind header plus payload plus padding |
| } |
| |
| // now we know the actual total length of the packet, get some memory |
| // but take SRTP data into account. Don't change total because some RTP |
| // functions rely on the fact that total is the overall size (without |
| // the SRTP data) |
| buffer = new unsigned char[total + srtpLength]; |
| *(reinterpret_cast<uint32*>(getHeader())) = 0; |
| getHeader()->version = CCRTP_VERSION; |
| if ( 0 != padding ) { |
| memset(buffer + total - padding,0,padding - 1); |
| buffer[total - 1] = padding; |
| getHeader()->padding = 1; |
| } else { |
| getHeader()->padding = 0; |
| } |
| } |
| |
| void RTPPacket::endPacket() |
| { |
| #ifdef CCXX_EXCEPTIONS |
| try { |
| #endif |
| delete [] buffer; |
| #ifdef CCXX_EXCEPTIONS |
| } catch (...) { }; |
| #endif |
| } |
| |
| void RTPPacket::reComputePayLength(bool padding) |
| { |
| // If payloadsize was computed without padding set then re-compute |
| // payloadSize after the padding bit was set and set padding flag |
| // in RTP header - option for SRTP |
| if (padding) { |
| size_t len = 0; |
| getHeader()->padding = 1; |
| len -= buffer[payloadSize - 1]; |
| payloadSize = (uint32)(payloadSize - len); |
| } |
| } |
| |
| OutgoingRTPPkt::OutgoingRTPPkt(const uint32* const csrcs, uint16 numcsrc, |
| const unsigned char* const hdrext, uint32 hdrextlen, |
| const unsigned char* const data, size_t datalen, |
| uint8 paddinglen, CryptoContext* pcc) : |
| RTPPacket((getSizeOfFixedHeader() + sizeof(uint32) * numcsrc + hdrextlen),datalen,paddinglen, pcc) |
| { |
| uint32 pointer = (uint32)getSizeOfFixedHeader(); |
| // add CSCR identifiers (putting them in network order). |
| setCSRCArray(csrcs,numcsrc); |
| pointer += numcsrc * sizeof(uint32); |
| |
| // add header extension. |
| setbuffer(hdrext,hdrextlen,pointer); |
| setExtension(hdrextlen > 0); |
| pointer += hdrextlen; |
| |
| // add data. |
| setbuffer(data,datalen,pointer); |
| } |
| |
| OutgoingRTPPkt::OutgoingRTPPkt(const uint32* const csrcs, uint16 numcsrc, |
| const unsigned char* data, size_t datalen, uint8 paddinglen, CryptoContext* pcc) : |
| RTPPacket((getSizeOfFixedHeader() + sizeof(uint32) *numcsrc),datalen, paddinglen, pcc) |
| { |
| uint32 pointer = (uint32)getSizeOfFixedHeader(); |
| // add CSCR identifiers (putting them in network order). |
| setCSRCArray(csrcs,numcsrc); |
| pointer += numcsrc * sizeof(uint32); |
| |
| // not needed, as the RTPPacket constructor sets by default |
| // the whole fixed header to 0. |
| // getHeader()->extension = 0; |
| |
| // add data. |
| setbuffer(data,datalen,pointer); |
| } |
| |
| OutgoingRTPPkt::OutgoingRTPPkt(const unsigned char* data, size_t datalen, |
| uint8 paddinglen, CryptoContext* pcc) : |
| RTPPacket(getSizeOfFixedHeader(),datalen,paddinglen, pcc) |
| { |
| // not needed, as the RTPPacket constructor sets by default |
| // the whole fixed header to 0. |
| //getHeader()->cc = 0; |
| //getHeader()->extension = 0; |
| |
| setbuffer(data,datalen,getSizeOfFixedHeader()); |
| } |
| |
| void OutgoingRTPPkt::setCSRCArray(const uint32* const csrcs, uint16 numcsrc) |
| { |
| setbuffer(csrcs, numcsrc * sizeof(uint32),getSizeOfFixedHeader()); |
| uint32* csrc = const_cast<uint32*>(getCSRCs()); |
| for ( int i = 0; i < numcsrc; i++ ) |
| csrc[i] = htonl(csrc[i]); |
| getHeader()->cc = numcsrc; |
| } |
| |
| void OutgoingRTPPkt::protect(uint32 ssrc, CryptoContext* pcc) |
| { |
| /* Encrypt the packet */ |
| uint64 index = ((uint64)pcc->getRoc() << 16) | (uint64)getSeqNum(); |
| |
| pcc->srtpEncrypt(this, index, ssrc); |
| |
| // NO MKI support yet - here we assume MKI is zero. To build in MKI |
| // take MKI length into account when storing the authentication tag. |
| |
| /* Compute MAC */ |
| pcc->srtpAuthenticate(this, pcc->getRoc(), |
| const_cast<uint8*>(getRawPacket()+srtpDataOffset) ); |
| /* Update the ROC if necessary */ |
| if (getSeqNum() == 0xFFFF ) { |
| pcc->setRoc(pcc->getRoc() + 1); |
| } |
| } |
| |
| // These masks are valid regardless of endianness. |
| const uint16 IncomingRTPPkt::RTP_INVALID_PT_MASK = (0x7e); |
| const uint16 IncomingRTPPkt::RTP_INVALID_PT_VALUE = (0x48); |
| |
| IncomingRTPPkt::IncomingRTPPkt(const unsigned char* const block, size_t len) : |
| RTPPacket(block,len) |
| { |
| // first, perform validity check: |
| // 1) check protocol version |
| // 2) it is not an SR nor an RR |
| // 3) consistent length field value (taking CC value and P and |
| // X bits into account) |
| if ( getProtocolVersion() != CCRTP_VERSION || (getPayloadType() & RTP_INVALID_PT_MASK) == RTP_INVALID_PT_VALUE) { |
| /* |
| || |
| getPayloadSize() <= 0 ) { |
| */ |
| headerValid = false; |
| return; |
| } |
| headerValid = true; |
| cachedTimestamp = getRawTimestamp(); |
| cachedSeqNum = ntohs(getHeader()->sequence); |
| cachedSSRC = ntohl(getHeader()->sources[0]); |
| } |
| |
| int32 IncomingRTPPkt::unprotect(CryptoContext* pcc) |
| { |
| if (pcc == NULL) { |
| return true; |
| } |
| |
| /* |
| * This is the setting of the packet data when we come to this |
| * point: |
| * |
| * total: complete length of received data |
| * buffer: points to data as received from network |
| * hdrSize: length of header including header extension |
| * payloadSize: length of data excluding hdrSize and padding |
| * |
| * Because this is an SRTP packet we need to adjust some values here. |
| * The SRTP MKI and authentication data is always at the end of a |
| * packet. Thus compute the position of this data. |
| */ |
| |
| uint32 srtpDataIndex = total - (pcc->getTagLength() + pcc->getMkiLength()); |
| |
| // now adjust total because some RTP functions rely on the fact that |
| // total is the full length of data without SRTP data. |
| total -= pcc->getTagLength() + pcc->getMkiLength(); |
| |
| // recompute payloadSize by subtracting SRTP data |
| payloadSize -= pcc->getTagLength() + pcc->getMkiLength(); |
| |
| // unused?? |
| // const uint8* mki = getRawPacket() + srtpDataIndex; |
| const uint8* tag = getRawPacket() + srtpDataIndex + pcc->getMkiLength(); |
| |
| /* Replay control */ |
| if (!pcc->checkReplay(cachedSeqNum)) { |
| return -2; |
| } |
| /* Guess the index */ |
| uint64 guessedIndex = pcc->guessIndex(cachedSeqNum); |
| |
| uint32 guessedRoc = guessedIndex >> 16; |
| uint8* mac = new uint8[pcc->getTagLength()]; |
| |
| pcc->srtpAuthenticate(this, guessedRoc, mac); |
| if (memcmp(tag, mac, pcc->getTagLength()) != 0) { |
| delete[] mac; |
| return -1; |
| } |
| delete[] mac; |
| |
| /* Decrypt the content */ |
| pcc->srtpEncrypt( this, guessedIndex, cachedSSRC ); |
| |
| /* Update the Crypto-context */ |
| pcc->update(cachedSeqNum); |
| |
| return 1; |
| } |
| |
| #ifdef CCXX_NAMESPACES |
| } |
| #endif |
| |
| /** EMACS ** |
| * Local variables: |
| * mode: c++ |
| * c-basic-offset: 4 |
| * End: |
| */ |