Revert 256580 "This CL adds methods to manipulate RTP header ext..."

trunk/src/content/browser/renderer_host/p2p/socket_host.cc

Index: trunk/src/content/browser/renderer_host/p2p/socket_host.cc
===================================================================
--- trunk/src/content/browser/renderer_host/p2p/socket_host.cc	(revision 256583)
+++ trunk/src/content/browser/renderer_host/p2p/socket_host.cc	(working copy)
@@ -8,386 +8,13 @@
 #include "content/browser/renderer_host/p2p/socket_host_tcp.h"
 #include "content/browser/renderer_host/p2p/socket_host_tcp_server.h"
 #include "content/browser/renderer_host/p2p/socket_host_udp.h"
-#include "crypto/hmac.h"
-#include "third_party/libjingle/source/talk/base/asyncpacketsocket.h"
-#include "third_party/libjingle/source/talk/base/byteorder.h"
-#include "third_party/libjingle/source/talk/base/messagedigest.h"
-#include "third_party/libjingle/source/talk/p2p/base/stun.h"
 
 namespace {
-
 const uint32 kStunMagicCookie = 0x2112A442;
-const int kMinRtpHdrLen = 12;
-const int kRtpExtnHdrLen = 4;
-const int kDtlsRecordHeaderLen = 13;
-const int kTurnChannelHdrLen = 4;
-const int kAbsSendTimeExtnLen = 3;
-const int kOneByteHdrLen = 1;
-
-// Fake auth tag written by the render process if external authentication is
-// enabled. HMAC in packet will be compared against this value before updating
-// packet with actual HMAC value.
-static const unsigned char kFakeAuthTag[10] = {
-    0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd
-};
-
-bool IsTurnChannelData(const char* data) {
-  return ((*data & 0xC0) == 0x40);
-}
-
-bool IsDtlsPacket(const char* data, int len) {
-  const uint8* u = reinterpret_cast<const uint8*>(data);
-  return (len >= kDtlsRecordHeaderLen && (u[0] > 19 && u[0] < 64));
-}
-
-bool IsRtcpPacket(const char* data) {
-  int type = (static_cast<uint8>(data[1]) & 0x7F);
-  return (type >= 64 && type < 96);
-}
-
-bool IsTurnSendIndicationPacket(const char* data) {
-  uint16 type = talk_base::GetBE16(data);
-  return (type == cricket::TURN_SEND_INDICATION);
-}
-
-bool IsRtpPacket(const char* data, int len) {
-  return ((*data & 0xC0) == 0x80);
-}
-
-// Verifies rtp header and message length.
-bool ValidateRtpHeader(char* rtp, int length) {
-  int cc_count = rtp[0] & 0x0F;
-  int rtp_hdr_len_without_extn = kMinRtpHdrLen + 4 * cc_count;
-  if (rtp_hdr_len_without_extn > length) {
-    return false;
-  }
-
-  // If extension bit is not set, we are done with header processing, as input
-  // length is verified above.
-  if (!(rtp[0] & 0x10)) {
-    return true;
-  }
-
-  rtp += rtp_hdr_len_without_extn;
-
-  // Getting extension profile length.
-  // Length is in 32 bit words.
-  uint16 extn_length = talk_base::GetBE16(rtp + 2) * 4;
-
-  // Verify input length against total header size.
-  if (rtp_hdr_len_without_extn + kRtpExtnHdrLen + extn_length > length) {
-    return false;
-  }
-  return true;
-}
-
-void UpdateAbsSendTimeExtnValue(char* extn_data, int len,
-                                uint32 abs_send_time) {
-  // Absolute send time in RTP streams.
-  //
-  // The absolute send time is signaled to the receiver in-band using the
-  // general mechanism for RTP header extensions [RFC5285]. The payload
-  // of this extension (the transmitted value) is a 24-bit unsigned integer
-  // containing the sender's current time in seconds as a fixed point number
-  // with 18 bits fractional part.
-  //
-  // The form of the absolute send time extension block:
-  //
-  //    0                   1                   2                   3
-  //    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-  //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-  //   |  ID   | len=2 |              absolute send time               |
-  //   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-  DCHECK_EQ(len, kAbsSendTimeExtnLen);
-  // Now() has resolution ~1-15ms, using HighResNow(). But it is warned not to
-  // use it unless necessary, as it is expensive than Now().
-  uint32 now_second = abs_send_time;
-  if (!now_second) {
-    uint64 now_us =
-        (base::TimeTicks::HighResNow() - base::TimeTicks()).InMicroseconds();
-    // Convert second to 24-bit unsigned with 18 bit fractional part
-    now_second =
-        ((now_us << 18) / base::Time::kMicrosecondsPerSecond) & 0x00FFFFFF;
-  }
-  // TODO(mallinath) - Add SetBE24 to byteorder.h in libjingle.
-  extn_data[0] = static_cast<uint8>(now_second >> 16);
-  extn_data[1] = static_cast<uint8>(now_second >> 8);
-  extn_data[2] = static_cast<uint8>(now_second);
-}
-
-// Assumes |len| is actual packet length + tag length. Updates HMAC at end of
-// the RTP packet.
-void UpdateRtpAuthTag(char* rtp, int len,
-                      const talk_base::PacketOptions& options) {
-  // If there is no key, return.
-  if (options.packet_time_params.srtp_auth_key.empty())
-    return;
-
-  size_t tag_length = options.packet_time_params.srtp_auth_tag_len;
-  char* auth_tag = rtp + (len - tag_length);
-
-  // We should have a fake HMAC value @ auth_tag.
-  DCHECK_EQ(0, memcmp(auth_tag, kFakeAuthTag, tag_length));
-
-  crypto::HMAC hmac(crypto::HMAC::SHA1);
-  if (!hmac.Init(reinterpret_cast<const unsigned char*>(
-        &options.packet_time_params.srtp_auth_key[0]),
-        options.packet_time_params.srtp_auth_key.size())) {
-    NOTREACHED();
-    return;
-  }
-
-  if (hmac.DigestLength() < tag_length) {
-    NOTREACHED();
-    return;
-  }
-
-  // Copy ROC after end of rtp packet.
-  memcpy(auth_tag, &options.packet_time_params.srtp_packet_index, 4);
-  // Authentication of a RTP packet will have RTP packet + ROC size.
-  int auth_required_length = len - tag_length + 4;
-
-  unsigned char output[64];
-  if (!hmac.Sign(base::StringPiece(rtp, auth_required_length),
-                 output, sizeof(output))) {
-    NOTREACHED();
-    return;
-  }
-  // Copy HMAC from output to packet. This is required as auth tag length
-  // may not be equal to the actual HMAC length.
-  memcpy(auth_tag, output, tag_length);
-}
-
 }  // namespace
 
 namespace content {
 
-namespace packet_processing_helpers {
-
-bool ApplyPacketOptions(char* data, int length,
-                        const talk_base::PacketOptions& options,
-                        uint32 abs_send_time) {
-  DCHECK(data != NULL);
-  DCHECK(length > 0);
-  // if there is no valid |rtp_sendtime_extension_id| and |srtp_auth_key| in
-  // PacketOptions, nothing to be updated in this packet.
-  if (options.packet_time_params.rtp_sendtime_extension_id == -1 &&
-      options.packet_time_params.srtp_auth_key.empty()) {
-    return true;
-  }
-
-  DCHECK(!IsDtlsPacket(data, length));
-  DCHECK(!IsRtcpPacket(data));
-
-  // If there is a srtp auth key present then packet must be a RTP packet.
-  // RTP packet may have been wrapped in a TURN Channel Data or
-  // TURN send indication.
-  int rtp_start_pos;
-  int rtp_length;
-  if (!GetRtpPacketStartPositionAndLength(
-      data, length, &rtp_start_pos, &rtp_length)) {
-    // This method should never return false.
-    NOTREACHED();
-    return false;
-  }
-
-  // Skip to rtp packet.
-  char* start = data + rtp_start_pos;
-  // If packet option has non default value (-1) for sendtime extension id,
-  // then we should parse the rtp packet to update the timestamp. Otherwise
-  // just calculate HMAC and update packet with it.
-  if (options.packet_time_params.rtp_sendtime_extension_id != -1) {
-    UpdateRtpAbsSendTimeExtn(
-        start, rtp_length,
-        options.packet_time_params.rtp_sendtime_extension_id, abs_send_time);
-  }
-
-  UpdateRtpAuthTag(start, rtp_length, options);
-  return true;
-}
-
-bool GetRtpPacketStartPositionAndLength(
-    char* packet, int length, int* rtp_start_pos, int* rtp_packet_length) {
-  int rtp_begin, rtp_length;
-  if (IsTurnChannelData(packet)) {
-    // Turn Channel Message header format.
-    //   0                   1                   2                   3
-    //  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-    // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    // |         Channel Number        |            Length             |
-    // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    // |                                                               |
-    // /                       Application Data                        /
-    // /                                                               /
-    // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    if (length < kTurnChannelHdrLen) {
-      return false;
-    }
-
-    rtp_begin = kTurnChannelHdrLen;
-    rtp_length = talk_base::GetBE16(&packet[2]);
-    if (length < rtp_length + kTurnChannelHdrLen) {
-      return false;
-    }
-  } else if (IsTurnSendIndicationPacket(packet)) {
-    if (length <= P2PSocketHost::kStunHeaderSize) {
-      // Message must be greater than 20 bytes, if it's carrying any payload.
-      return false;
-    }
-    // Validate STUN message length.
-    int stun_msg_len = talk_base::GetBE16(&packet[2]);
-    if (stun_msg_len + P2PSocketHost::kStunHeaderSize != length) {
-      return false;
-    }
-
-    // First skip mandatory stun header which is of 20 bytes.
-    rtp_begin = P2PSocketHost::kStunHeaderSize;
-    // Loop through STUN attributes until we find STUN DATA attribute.
-    char* start = packet + rtp_begin;
-    bool data_attr_present = false;
-    while ((packet + rtp_begin) - start < length) {
-      // Keep reading STUN attributes until we hit DATA attribute.
-      // Attribute will be a TLV structure.
-      // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-      // |         Type                  |            Length             |
-      // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-      // |                         Value (variable)                ....
-      // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-      // The value in the length field MUST contain the length of the Value
-      // part of the attribute, prior to padding, measured in bytes.  Since
-      // STUN aligns attributes on 32-bit boundaries, attributes whose content
-      // is not a multiple of 4 bytes are padded with 1, 2, or 3 bytes of
-      // padding so that its value contains a multiple of 4 bytes.  The
-      // padding bits are ignored, and may be any value.
-      uint16 attr_type, attr_length;
-      // Getting attribute type and length.
-      attr_type = talk_base::GetBE16(&packet[rtp_begin]);
-      attr_length = talk_base::GetBE16(
-          &packet[rtp_begin + sizeof(attr_type)]);
-      // Checking for bogus attribute length.
-      if (length < attr_length + rtp_begin) {
-        return false;
-      }
-
-      if (attr_type != cricket::STUN_ATTR_DATA) {
-        rtp_begin += sizeof(attr_type) + sizeof(attr_length) + attr_length;
-        if ((attr_length % 4) != 0) {
-          rtp_begin += (4 - (attr_length % 4));
-        }
-        continue;
-      }
-
-      data_attr_present = true;
-      rtp_begin += 4;  // Skip STUN_DATA_ATTR header.
-      rtp_length = attr_length;
-      // One final check of length before exiting.
-      if (length < rtp_length + rtp_begin) {
-        return false;
-      }
-      // We found STUN_DATA_ATTR. We can skip parsing rest of the packet.
-      break;
-    }
-
-    if (!data_attr_present) {
-      // There is no data attribute present in the message. We can't do anything
-      // with the message.
-      return false;
-    }
-
-  } else {
-    // This is a raw RTP packet.
-    rtp_begin = 0;
-    rtp_length = length;
-  }
-
-  // Making sure we have a valid RTP packet at the end.
-  if (IsRtpPacket(packet + rtp_begin, rtp_length) &&
-      ValidateRtpHeader(packet + rtp_begin, rtp_length)) {
-    *rtp_start_pos = rtp_begin;
-    *rtp_packet_length = rtp_length;
-    return true;
-  }
-  return false;
-}
-
-// ValidateRtpHeader must be called before this method to make sure, we have
-// a sane rtp packet.
-bool UpdateRtpAbsSendTimeExtn(char* rtp, int length,
-                              int extension_id, uint32 abs_send_time) {
-  //  0                   1                   2                   3
-  //  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-  // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-  // |V=2|P|X|  CC   |M|     PT      |       sequence number         |
-  // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-  // |                           timestamp                           |
-  // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-  // |           synchronization source (SSRC) identifier            |
-  // +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
-  // |            contributing source (CSRC) identifiers             |
-  // |                             ....                              |
-  // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-
-  // Return if extension bit is not set.
-  if (!(rtp[0] & 0x10)) {
-    return true;
-  }
-
-  int cc_count = rtp[0] & 0x0F;
-  int rtp_hdr_len_without_extn = kMinRtpHdrLen + 4 * cc_count;
-
-  rtp += rtp_hdr_len_without_extn;
-
-  // Getting extension profile ID and length.
-  uint16 profile_id = talk_base::GetBE16(rtp);
-  // Length is in 32 bit words.
-  uint16 extn_length = talk_base::GetBE16(rtp + 2) * 4;
-
-  rtp += kRtpExtnHdrLen;  // Moving past extn header.
-
-  bool found = false;
-  // WebRTC is using one byte header extension.
-  // TODO(mallinath) - Handle two byte header extension.
-  if (profile_id == 0xBEDE) {  // OneByte extension header
-    //  0
-    //  0 1 2 3 4 5 6 7
-    // +-+-+-+-+-+-+-+-+
-    // |  ID   |  len  |
-    // +-+-+-+-+-+-+-+-+
-
-    //  0                   1                   2                   3
-    //  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-    // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    // |       0xBE    |    0xDE       |           length=3            |
-    // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    // |  ID   | L=0   |     data      |  ID   |  L=1  |   data...
-    // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    //       ...data   |    0 (pad)    |    0 (pad)    |  ID   | L=3   |
-    // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    // |                          data                                 |
-    // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    char* extn_start = rtp;
-    while (rtp - extn_start < extn_length) {
-      const int id = (*rtp & 0xF0) >> 4;
-      const int len = (*rtp & 0x0F) + 1;
-      // The 4-bit length is the number minus one of data bytes of this header
-      // extension element following the one-byte header.
-      if (id == extension_id) {
-        UpdateAbsSendTimeExtnValue(rtp + kOneByteHdrLen, len, abs_send_time);
-        found = true;
-        break;
-      }
-      rtp += kOneByteHdrLen + len;
-      // Counting padding bytes.
-      while ((*rtp == 0) && (rtp - extn_start < extn_length)) {
-        ++rtp;
-      }
-    }
-  }
-  return found;
-}
-
-}  // packet_processing_helpers
-
 P2PSocketHost::P2PSocketHost(IPC::Sender* message_sender,
                              int id)
     : message_sender_(message_sender),