Cast:Splitting rtcp sender

media/cast/net/rtcp/rtcp_builder.cc

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/cast/net/rtcp/rtcp_builder.h"
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+#include "base/logging.h"
+#include "media/cast/net/cast_net_defines.h"
+#include "media/cast/net/pacing/paced_sender.h"
+#include "media/cast/rtcp/rtcp_utility.h"
+#include "net/base/big_endian.h"
+
+static const size_t kRtcpCastLogHeaderSize = 12;
+static const size_t kRtcpSenderFrameLogSize = 4;
+static const size_t kRtcpReceiverFrameLogSize = 8;
+static const size_t kRtcpReceiverEventLogSize = 4;
+
+namespace media {
+namespace cast {
+
+RtcpBuilder::RtcpBuilder(PacedPacketSender* outgoing_transport,
+                             uint32 sending_ssrc,
+                             const std::string& c_name)
+     : ssrc_(sending_ssrc),
+       c_name_(c_name),
+       transport_(outgoing_transport) {
+  DCHECK_LT(c_name_.length(), kRtcpCnameSize) << "Invalid config";
+}
+
+RtcpBuilder::~RtcpBuilder() {}
+
+void RtcpBuilder::SendRtcpFromRtpSender(uint32 packet_type_flags,
+                                          const RtcpSenderInfo* sender_info,
+                                          const RtcpDlrrReportBlock* dlrr,
+                                          RtcpSenderLogMessage* sender_log) {
+  if (packet_type_flags & kRtcpRr ||
+      packet_type_flags & kRtcpPli ||
+      packet_type_flags & kRtcpRrtr ||
+      packet_type_flags & kRtcpCast ||
+      packet_type_flags & kRtcpReceiverLog ||
+      packet_type_flags & kRtcpRpsi ||
+      packet_type_flags & kRtcpRemb ||
+      packet_type_flags & kRtcpNack) {
+    NOTREACHED() << "Invalid argument";
+  }
+
+  std::vector<uint8> packet;
+  packet.reserve(kIpPacketSize);
+  if (packet_type_flags & kRtcpSr) {
+    DCHECK(sender_info) << "Invalid argument";
+    BuildSR(*sender_info, NULL, &packet);
+    BuildSdec(&packet);
+  }
+  if (packet_type_flags & kRtcpBye) {
+    BuildBye(&packet);
+  }
+  if (packet_type_flags & kRtcpDlrr) {
+    DCHECK(dlrr) << "Invalid argument";
+    BuildDlrrRb(dlrr, &packet);
+  }
+  if (packet_type_flags & kRtcpSenderLog) {
+    DCHECK(sender_log) << "Invalid argument";
+    BuildSenderLog(sender_log, &packet);
+  }
+  if (packet.empty())
+    return;  // Sanity don't send empty packets.
+
+  transport_->SendRtcpPacket(packet);
+}
+
+void RtcpBuilder::BuildSR(const RtcpSenderInfo& sender_info,
+                            const RtcpReportBlock* report_block,
+                            std::vector<uint8>* packet) const {
+  // Sender report.
+  size_t start_size = packet->size();
+  DCHECK_LT(start_size + 52, kIpPacketSize) << "Not enough buffer space";
+  if (start_size + 52 > kIpPacketSize) return;
+
+  uint16 number_of_rows = (report_block) ? 12 : 6;
+  packet->resize(start_size + 28);
+
+  net::BigEndianWriter big_endian_writer(&((*packet)[start_size]), 28);
+  big_endian_writer.WriteU8(0x80 + (report_block ? 1 : 0));
+  big_endian_writer.WriteU8(kPacketTypeSenderReport);
+  big_endian_writer.WriteU16(number_of_rows);
+  big_endian_writer.WriteU32(ssrc_);
+  big_endian_writer.WriteU32(sender_info.ntp_seconds);
+  big_endian_writer.WriteU32(sender_info.ntp_fraction);
+  big_endian_writer.WriteU32(sender_info.rtp_timestamp);
+  big_endian_writer.WriteU32(sender_info.send_packet_count);
+  big_endian_writer.WriteU32(static_cast<uint32>(sender_info.send_octet_count));
+
+  if (report_block) {
+    AddReportBlocks(*report_block, packet);  // Adds 24 bytes.
+  }
+}
+
+void RtcpBuilder::AddReportBlocks(const RtcpReportBlock& report_block,
+                                    std::vector<uint8>* packet) const {
+  size_t start_size = packet->size();
+  DCHECK_LT(start_size + 24, kIpPacketSize) << "Not enough buffer space";
+  if (start_size + 24 > kIpPacketSize) return;
+
+  packet->resize(start_size + 24);
+
+  net::BigEndianWriter big_endian_writer(&((*packet)[start_size]), 24);
+  big_endian_writer.WriteU32(report_block.media_ssrc);
+  big_endian_writer.WriteU8(report_block.fraction_lost);
+  big_endian_writer.WriteU8(report_block.cumulative_lost >> 16);
+  big_endian_writer.WriteU8(report_block.cumulative_lost >> 8);
+  big_endian_writer.WriteU8(report_block.cumulative_lost);
+
+  // Extended highest seq_no, contain the highest sequence number received.
+  big_endian_writer.WriteU32(report_block.extended_high_sequence_number);
+  big_endian_writer.WriteU32(report_block.jitter);
+
+  // Last SR timestamp; our NTP time when we received the last report.
+  // This is the value that we read from the send report packet not when we
+  // received it.
+  big_endian_writer.WriteU32(report_block.last_sr);
+
+  // Delay since last received report, time since we received the report.
+  big_endian_writer.WriteU32(report_block.delay_since_last_sr);
+}
+
+void RtcpBuilder::BuildSdec(std::vector<uint8>* packet) const {
+  size_t start_size = packet->size();
+  DCHECK_LT(start_size +  12 + c_name_.length(), kIpPacketSize)
+      << "Not enough buffer space";
+  if (start_size + 12 > kIpPacketSize) return;
+
+  // SDES Source Description.
+  packet->resize(start_size + 10);
+
+  net::BigEndianWriter big_endian_writer(&((*packet)[start_size]), 10);
+  // We always need to add one SDES CNAME.
+  big_endian_writer.WriteU8(0x80 + 1);
+  big_endian_writer.WriteU8(kPacketTypeSdes);
+
+  // Handle SDES length later on.
+  uint32 sdes_length_position = static_cast<uint32>(start_size) + 3;
+  big_endian_writer.WriteU16(0);
+  big_endian_writer.WriteU32(ssrc_);  // Add our own SSRC.
+  big_endian_writer.WriteU8(1);  // CNAME = 1
+  big_endian_writer.WriteU8(static_cast<uint8>(c_name_.length()));
+
+  size_t sdes_length = 10 + c_name_.length();
+  packet->insert(packet->end(), c_name_.c_str(),
+                 c_name_.c_str() + c_name_.length());
+
+  size_t padding = 0;
+
+  // We must have a zero field even if we have an even multiple of 4 bytes.
+  if ((packet->size() % 4) == 0) {
+    padding++;
+    packet->push_back(0);
+  }
+  while ((packet->size() % 4) != 0) {
+    padding++;
+    packet->push_back(0);
+  }
+  sdes_length += padding;
+
+  // In 32-bit words minus one and we don't count the header.
+  uint8 buffer_length = static_cast<uint8>((sdes_length / 4) - 1);
+  (*packet)[sdes_length_position] = buffer_length;
+}
+
+void RtcpBuilder::BuildBye(std::vector<uint8>* packet) const {
+  size_t start_size = packet->size();
+  DCHECK_LT(start_size + 8, kIpPacketSize) << "Not enough buffer space";
+  if (start_size + 8 > kIpPacketSize) return;
+
+  packet->resize(start_size + 8);
+
+  net::BigEndianWriter big_endian_writer(&((*packet)[start_size]), 8);
+  big_endian_writer.WriteU8(0x80 + 1);
+  big_endian_writer.WriteU8(kPacketTypeBye);
+  big_endian_writer.WriteU16(1);  // Length.
+  big_endian_writer.WriteU32(ssrc_);  // Add our own SSRC.
+}
+
+/*
+   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|reserved |   PT=XR=207   |             length            |
+  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+  |                              SSRC                             |
+  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+  |     BT=5      |   reserved    |         block length          |
+  +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
+  |                 SSRC_1 (SSRC of first receiver)               | sub-
+  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ block
+  |                         last RR (LRR)                         |   1
+  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+  |                   delay since last RR (DLRR)                  |
+  +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
+*/
+void RtcpBuilder::BuildDlrrRb(const RtcpDlrrReportBlock* dlrr,
+                                std::vector<uint8>* packet) const {
+  size_t start_size = packet->size();
+  DCHECK_LT(start_size + 24, kIpPacketSize) << "Not enough buffer space";
+  if (start_size + 24 > kIpPacketSize) return;
+
+  packet->resize(start_size + 24);
+
+  net::BigEndianWriter big_endian_writer(&((*packet)[start_size]), 24);
+  big_endian_writer.WriteU8(0x80);
+  big_endian_writer.WriteU8(kPacketTypeXr);
+  big_endian_writer.WriteU16(5);  // Length.
+  big_endian_writer.WriteU32(ssrc_);  // Add our own SSRC.
+  big_endian_writer.WriteU8(5);  // Add block type.
+  big_endian_writer.WriteU8(0);  // Add reserved.
+  big_endian_writer.WriteU16(3);  // Block length.
+  big_endian_writer.WriteU32(ssrc_);  // Add the media (received RTP) SSRC.
+  big_endian_writer.WriteU32(dlrr->last_rr);
+  big_endian_writer.WriteU32(dlrr->delay_since_last_rr);
+}
+
+void RtcpBuilder::BuildSenderLog(RtcpSenderLogMessage* sender_log_message,
+                                   std::vector<uint8>* packet) const {
+  DCHECK(sender_log_message);
+  DCHECK(packet);
+  size_t start_size = packet->size();
+  size_t remaining_space = kIpPacketSize - start_size;
+  DCHECK_GE(remaining_space, kRtcpCastLogHeaderSize + kRtcpSenderFrameLogSize)
+       << "Not enough buffer space";
+  if (remaining_space < kRtcpCastLogHeaderSize + kRtcpSenderFrameLogSize)
+    return;
+
+  size_t space_for_x_messages =
+      (remaining_space - kRtcpCastLogHeaderSize) / kRtcpSenderFrameLogSize;
+  size_t number_of_messages = std::min(space_for_x_messages,
+                                       sender_log_message->size());
+
+  size_t log_size = kRtcpCastLogHeaderSize +
+      number_of_messages * kRtcpSenderFrameLogSize;
+  packet->resize(start_size + log_size);
+
+  net::BigEndianWriter big_endian_writer(&((*packet)[start_size]), log_size);
+  big_endian_writer.WriteU8(0x80 + kSenderLogSubtype);
+  big_endian_writer.WriteU8(kPacketTypeApplicationDefined);
+  big_endian_writer.WriteU16(static_cast<uint16>(2 + number_of_messages));
+  big_endian_writer.WriteU32(ssrc_);  // Add our own SSRC.
+  big_endian_writer.WriteU32(kCast);
+
+  for (; number_of_messages > 0; --number_of_messages) {
+    DCHECK(!sender_log_message->empty());
+    const RtcpSenderFrameLogMessage& message = sender_log_message->front();
+    big_endian_writer.WriteU8(static_cast<uint8>(message.frame_status));
+    // We send the 24 east significant bits of the RTP timestamp.
+    big_endian_writer.WriteU8(static_cast<uint8>(message.rtp_timestamp >> 16));
+    big_endian_writer.WriteU8(static_cast<uint8>(message.rtp_timestamp >> 8));
+    big_endian_writer.WriteU8(static_cast<uint8>(message.rtp_timestamp));
+    sender_log_message->pop_front();
+  }
+}
+
+}  // namespace cast
+}  // namespace media