Reland of: Separating SCTP code from BaseChannel/MediaChannel.

webrtc/media/sctp/sctpdataengine.cc

Index: webrtc/media/sctp/sctpdataengine.cc
diff --git a/webrtc/media/sctp/sctpdataengine.cc b/webrtc/media/sctp/sctpdataengine.cc
deleted file mode 100644
index 103aebdd9b17171d66587b71f83245c1e8e8d995..0000000000000000000000000000000000000000
--- a/webrtc/media/sctp/sctpdataengine.cc
+++ /dev/null
@@ -1,1066 +0,0 @@
-/*
- *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#include "webrtc/media/sctp/sctpdataengine.h"
-
-#include <stdarg.h>
-#include <stdio.h>
-
-#include <memory>
-#include <sstream>
-#include <vector>
-
-#include "usrsctplib/usrsctp.h"
-#include "webrtc/base/arraysize.h"
-#include "webrtc/base/copyonwritebuffer.h"
-#include "webrtc/base/criticalsection.h"
-#include "webrtc/base/helpers.h"
-#include "webrtc/base/logging.h"
-#include "webrtc/base/safe_conversions.h"
-#include "webrtc/media/base/codec.h"
-#include "webrtc/media/base/mediaconstants.h"
-#include "webrtc/media/base/streamparams.h"
-
-namespace cricket {
-// The biggest SCTP packet. Starting from a 'safe' wire MTU value of 1280,
-// take off 80 bytes for DTLS/TURN/TCP/IP overhead.
-static constexpr size_t kSctpMtu = 1200;
-
-// The size of the SCTP association send buffer.  256kB, the usrsctp default.
-static constexpr int kSendBufferSize = 262144;
-
-struct SctpInboundPacket {
-  rtc::CopyOnWriteBuffer buffer;
-  ReceiveDataParams params;
-  // The |flags| parameter is used by SCTP to distinguish notification packets
-  // from other types of packets.
-  int flags;
-};
-
-namespace {
-// Set the initial value of the static SCTP Data Engines reference count.
-int g_usrsctp_usage_count = 0;
-rtc::GlobalLockPod g_usrsctp_lock_;
-
-typedef SctpDataMediaChannel::StreamSet StreamSet;
-
-// Returns a comma-separated, human-readable list of the stream IDs in 's'
-std::string ListStreams(const StreamSet& s) {
-  std::stringstream result;
-  bool first = true;
-  for (StreamSet::const_iterator it = s.begin(); it != s.end(); ++it) {
-    if (!first) {
-      result << ", " << *it;
-    } else {
-      result << *it;
-      first = false;
-    }
-  }
-  return result.str();
-}
-
-// Returns a pipe-separated, human-readable list of the SCTP_STREAM_RESET
-// flags in 'flags'
-std::string ListFlags(int flags) {
-  std::stringstream result;
-  bool first = true;
-  // Skip past the first 12 chars (strlen("SCTP_STREAM_"))
-#define MAKEFLAG(X) { X, #X + 12}
-  struct flaginfo_t {
-    int value;
-    const char* name;
-  } flaginfo[] = {
-    MAKEFLAG(SCTP_STREAM_RESET_INCOMING_SSN),
-    MAKEFLAG(SCTP_STREAM_RESET_OUTGOING_SSN),
-    MAKEFLAG(SCTP_STREAM_RESET_DENIED),
-    MAKEFLAG(SCTP_STREAM_RESET_FAILED),
-    MAKEFLAG(SCTP_STREAM_CHANGE_DENIED)
-  };
-#undef MAKEFLAG
-  for (uint32_t i = 0; i < arraysize(flaginfo); ++i) {
-    if (flags & flaginfo[i].value) {
-      if (!first) result << " | ";
-      result << flaginfo[i].name;
-      first = false;
-    }
-  }
-  return result.str();
-}
-
-// Returns a comma-separated, human-readable list of the integers in 'array'.
-// All 'num_elems' of them.
-std::string ListArray(const uint16_t* array, int num_elems) {
-  std::stringstream result;
-  for (int i = 0; i < num_elems; ++i) {
-    if (i) {
-      result << ", " << array[i];
-    } else {
-      result << array[i];
-    }
-  }
-  return result.str();
-}
-
-typedef rtc::ScopedMessageData<SctpInboundPacket> InboundPacketMessage;
-typedef rtc::ScopedMessageData<rtc::CopyOnWriteBuffer> OutboundPacketMessage;
-
-enum {
-  MSG_SCTPINBOUNDPACKET = 1,   // MessageData is SctpInboundPacket
-  MSG_SCTPOUTBOUNDPACKET = 2,  // MessageData is rtc:Buffer
-};
-
-// Helper for logging SCTP messages.
-void DebugSctpPrintf(const char* format, ...) {
-#if RTC_DCHECK_IS_ON
-  char s[255];
-  va_list ap;
-  va_start(ap, format);
-  vsnprintf(s, sizeof(s), format, ap);
-  LOG(LS_INFO) << "SCTP: " << s;
-  va_end(ap);
-#endif
-}
-
-// Get the PPID to use for the terminating fragment of this type.
-SctpDataMediaChannel::PayloadProtocolIdentifier GetPpid(DataMessageType type) {
-  switch (type) {
-  default:
-  case DMT_NONE:
-    return SctpDataMediaChannel::PPID_NONE;
-  case DMT_CONTROL:
-    return SctpDataMediaChannel::PPID_CONTROL;
-  case DMT_BINARY:
-    return SctpDataMediaChannel::PPID_BINARY_LAST;
-  case DMT_TEXT:
-    return SctpDataMediaChannel::PPID_TEXT_LAST;
-  };
-}
-
-bool GetDataMediaType(SctpDataMediaChannel::PayloadProtocolIdentifier ppid,
-                      DataMessageType* dest) {
-  ASSERT(dest != NULL);
-  switch (ppid) {
-    case SctpDataMediaChannel::PPID_BINARY_PARTIAL:
-    case SctpDataMediaChannel::PPID_BINARY_LAST:
-      *dest = DMT_BINARY;
-      return true;
-
-    case SctpDataMediaChannel::PPID_TEXT_PARTIAL:
-    case SctpDataMediaChannel::PPID_TEXT_LAST:
-      *dest = DMT_TEXT;
-      return true;
-
-    case SctpDataMediaChannel::PPID_CONTROL:
-      *dest = DMT_CONTROL;
-      return true;
-
-    case SctpDataMediaChannel::PPID_NONE:
-      *dest = DMT_NONE;
-      return true;
-
-    default:
-      return false;
-  }
-}
-
-// Log the packet in text2pcap format, if log level is at LS_VERBOSE.
-void VerboseLogPacket(const void* data, size_t length, int direction) {
-  if (LOG_CHECK_LEVEL(LS_VERBOSE) && length > 0) {
-    char *dump_buf;
-    // Some downstream project uses an older version of usrsctp that expects
-    // a non-const "void*" as first parameter when dumping the packet, so we
-    // need to cast the const away here to avoid a compiler error.
-    if ((dump_buf = usrsctp_dumppacket(
-        const_cast<void*>(data), length, direction)) != NULL) {
-      LOG(LS_VERBOSE) << dump_buf;
-      usrsctp_freedumpbuffer(dump_buf);
-    }
-  }
-}
-
-// This is the callback usrsctp uses when there's data to send on the network
-// that has been wrapped appropriatly for the SCTP protocol.
-int OnSctpOutboundPacket(void* addr,
-                         void* data,
-                         size_t length,
-                         uint8_t tos,
-                         uint8_t set_df) {
-  SctpDataMediaChannel* channel = static_cast<SctpDataMediaChannel*>(addr);
-  LOG(LS_VERBOSE) << "global OnSctpOutboundPacket():"
-                  << "addr: " << addr << "; length: " << length
-                  << "; tos: " << std::hex << static_cast<int>(tos)
-                  << "; set_df: " << std::hex << static_cast<int>(set_df);
-
-  VerboseLogPacket(data, length, SCTP_DUMP_OUTBOUND);
-  // Note: We have to copy the data; the caller will delete it.
-  auto* msg = new OutboundPacketMessage(
-      new rtc::CopyOnWriteBuffer(reinterpret_cast<uint8_t*>(data), length));
-  channel->worker_thread()->Post(RTC_FROM_HERE, channel, MSG_SCTPOUTBOUNDPACKET,
-                                 msg);
-  return 0;
-}
-
-// This is the callback called from usrsctp when data has been received, after
-// a packet has been interpreted and parsed by usrsctp and found to contain
-// payload data. It is called by a usrsctp thread. It is assumed this function
-// will free the memory used by 'data'.
-int OnSctpInboundPacket(struct socket* sock,
-                        union sctp_sockstore addr,
-                        void* data,
-                        size_t length,
-                        struct sctp_rcvinfo rcv,
-                        int flags,
-                        void* ulp_info) {
-  SctpDataMediaChannel* channel = static_cast<SctpDataMediaChannel*>(ulp_info);
-  // Post data to the channel's receiver thread (copying it).
-  // TODO(ldixon): Unclear if copy is needed as this method is responsible for
-  // memory cleanup. But this does simplify code.
-  const SctpDataMediaChannel::PayloadProtocolIdentifier ppid =
-      static_cast<SctpDataMediaChannel::PayloadProtocolIdentifier>(
-          rtc::HostToNetwork32(rcv.rcv_ppid));
-  DataMessageType type = DMT_NONE;
-  if (!GetDataMediaType(ppid, &type) && !(flags & MSG_NOTIFICATION)) {
-    // It's neither a notification nor a recognized data packet.  Drop it.
-    LOG(LS_ERROR) << "Received an unknown PPID " << ppid
-                  << " on an SCTP packet.  Dropping.";
-  } else {
-    SctpInboundPacket* packet = new SctpInboundPacket;
-    packet->buffer.SetData(reinterpret_cast<uint8_t*>(data), length);
-    packet->params.ssrc = rcv.rcv_sid;
-    packet->params.seq_num = rcv.rcv_ssn;
-    packet->params.timestamp = rcv.rcv_tsn;
-    packet->params.type = type;
-    packet->flags = flags;
-    // The ownership of |packet| transfers to |msg|.
-    InboundPacketMessage* msg = new InboundPacketMessage(packet);
-    channel->worker_thread()->Post(RTC_FROM_HERE, channel,
-                                   MSG_SCTPINBOUNDPACKET, msg);
-  }
-  free(data);
-  return 1;
-}
-
-void InitializeUsrSctp() {
-  LOG(LS_INFO) << __FUNCTION__;
-  // First argument is udp_encapsulation_port, which is not releveant for our
-  // AF_CONN use of sctp.
-  usrsctp_init(0, &OnSctpOutboundPacket, &DebugSctpPrintf);
-
-  // To turn on/off detailed SCTP debugging. You will also need to have the
-  // SCTP_DEBUG cpp defines flag.
-  // usrsctp_sysctl_set_sctp_debug_on(SCTP_DEBUG_ALL);
-
-  // TODO(ldixon): Consider turning this on/off.
-  usrsctp_sysctl_set_sctp_ecn_enable(0);
-
-  // This is harmless, but we should find out when the library default
-  // changes.
-  int send_size = usrsctp_sysctl_get_sctp_sendspace();
-  if (send_size != kSendBufferSize) {
-    LOG(LS_ERROR) << "Got different send size than expected: " << send_size;
-  }
-
-  // TODO(ldixon): Consider turning this on/off.
-  // This is not needed right now (we don't do dynamic address changes):
-  // If SCTP Auto-ASCONF is enabled, the peer is informed automatically
-  // when a new address is added or removed. This feature is enabled by
-  // default.
-  // usrsctp_sysctl_set_sctp_auto_asconf(0);
-
-  // TODO(ldixon): Consider turning this on/off.
-  // Add a blackhole sysctl. Setting it to 1 results in no ABORTs
-  // being sent in response to INITs, setting it to 2 results
-  // in no ABORTs being sent for received OOTB packets.
-  // This is similar to the TCP sysctl.
-  //
-  // See: http://lakerest.net/pipermail/sctp-coders/2012-January/009438.html
-  // See: http://svnweb.freebsd.org/base?view=revision&revision=229805
-  // usrsctp_sysctl_set_sctp_blackhole(2);
-
-  // Set the number of default outgoing streams. This is the number we'll
-  // send in the SCTP INIT message.
-  usrsctp_sysctl_set_sctp_nr_outgoing_streams_default(kMaxSctpStreams);
-}
-
-void UninitializeUsrSctp() {
-  LOG(LS_INFO) << __FUNCTION__;
-  // usrsctp_finish() may fail if it's called too soon after the channels are
-  // closed. Wait and try again until it succeeds for up to 3 seconds.
-  for (size_t i = 0; i < 300; ++i) {
-    if (usrsctp_finish() == 0) {
-      return;
-    }
-
-    rtc::Thread::SleepMs(10);
-  }
-  LOG(LS_ERROR) << "Failed to shutdown usrsctp.";
-}
-
-void IncrementUsrSctpUsageCount() {
-  rtc::GlobalLockScope lock(&g_usrsctp_lock_);
-  if (!g_usrsctp_usage_count) {
-    InitializeUsrSctp();
-  }
-  ++g_usrsctp_usage_count;
-}
-
-void DecrementUsrSctpUsageCount() {
-  rtc::GlobalLockScope lock(&g_usrsctp_lock_);
-  --g_usrsctp_usage_count;
-  if (!g_usrsctp_usage_count) {
-    UninitializeUsrSctp();
-  }
-}
-
-DataCodec GetSctpDataCodec() {
-  DataCodec codec(kGoogleSctpDataCodecPlType, kGoogleSctpDataCodecName);
-  codec.SetParam(kCodecParamPort, kSctpDefaultPort);
-  return codec;
-}
-
-}  // namespace
-
-SctpDataEngine::SctpDataEngine() : codecs_(1, GetSctpDataCodec()) {}
-
-SctpDataEngine::~SctpDataEngine() {}
-
-// Called on the worker thread.
-DataMediaChannel* SctpDataEngine::CreateChannel(
-    DataChannelType data_channel_type,
-    const MediaConfig& config) {
-  if (data_channel_type != DCT_SCTP) {
-    return NULL;
-  }
-  return new SctpDataMediaChannel(rtc::Thread::Current(), config);
-}
-
-// static
-SctpDataMediaChannel* SctpDataMediaChannel::GetChannelFromSocket(
-    struct socket* sock) {
-  struct sockaddr* addrs = nullptr;
-  int naddrs = usrsctp_getladdrs(sock, 0, &addrs);
-  if (naddrs <= 0 || addrs[0].sa_family != AF_CONN) {
-    return nullptr;
-  }
-  // usrsctp_getladdrs() returns the addresses bound to this socket, which
-  // contains the SctpDataMediaChannel* as sconn_addr.  Read the pointer,
-  // then free the list of addresses once we have the pointer.  We only open
-  // AF_CONN sockets, and they should all have the sconn_addr set to the
-  // pointer that created them, so [0] is as good as any other.
-  struct sockaddr_conn* sconn =
-      reinterpret_cast<struct sockaddr_conn*>(&addrs[0]);
-  SctpDataMediaChannel* channel =
-      reinterpret_cast<SctpDataMediaChannel*>(sconn->sconn_addr);
-  usrsctp_freeladdrs(addrs);
-
-  return channel;
-}
-
-// static
-int SctpDataMediaChannel::SendThresholdCallback(struct socket* sock,
-                                                uint32_t sb_free) {
-  // Fired on our I/O thread.  SctpDataMediaChannel::OnPacketReceived() gets
-  // a packet containing acknowledgments, which goes into usrsctp_conninput,
-  // and then back here.
-  SctpDataMediaChannel* channel = GetChannelFromSocket(sock);
-  if (!channel) {
-    LOG(LS_ERROR) << "SendThresholdCallback: Failed to get channel for socket "
-                  << sock;
-    return 0;
-  }
-  channel->OnSendThresholdCallback();
-  return 0;
-}
-
-SctpDataMediaChannel::SctpDataMediaChannel(rtc::Thread* thread,
-                                           const MediaConfig& config)
-    : DataMediaChannel(config),
-      worker_thread_(thread),
-      local_port_(kSctpDefaultPort),
-      remote_port_(kSctpDefaultPort),
-      sock_(NULL),
-      sending_(false),
-      receiving_(false),
-      debug_name_("SctpDataMediaChannel") {}
-
-SctpDataMediaChannel::~SctpDataMediaChannel() {
-  CloseSctpSocket();
-}
-
-void SctpDataMediaChannel::OnSendThresholdCallback() {
-  RTC_DCHECK(rtc::Thread::Current() == worker_thread_);
-  SignalReadyToSend(true);
-}
-
-sockaddr_conn SctpDataMediaChannel::GetSctpSockAddr(int port) {
-  sockaddr_conn sconn = {0};
-  sconn.sconn_family = AF_CONN;
-#ifdef HAVE_SCONN_LEN
-  sconn.sconn_len = sizeof(sockaddr_conn);
-#endif
-  // Note: conversion from int to uint16_t happens here.
-  sconn.sconn_port = rtc::HostToNetwork16(port);
-  sconn.sconn_addr = this;
-  return sconn;
-}
-
-bool SctpDataMediaChannel::OpenSctpSocket() {
-  if (sock_) {
-    LOG(LS_VERBOSE) << debug_name_
-                    << "->Ignoring attempt to re-create existing socket.";
-    return false;
-  }
-
-  IncrementUsrSctpUsageCount();
-
-  // If kSendBufferSize isn't reflective of reality, we log an error, but we
-  // still have to do something reasonable here.  Look up what the buffer's
-  // real size is and set our threshold to something reasonable.
-  const static int kSendThreshold = usrsctp_sysctl_get_sctp_sendspace() / 2;
-
-  sock_ = usrsctp_socket(
-      AF_CONN, SOCK_STREAM, IPPROTO_SCTP, OnSctpInboundPacket,
-      &SctpDataMediaChannel::SendThresholdCallback, kSendThreshold, this);
-  if (!sock_) {
-    LOG_ERRNO(LS_ERROR) << debug_name_ << "Failed to create SCTP socket.";
-    DecrementUsrSctpUsageCount();
-    return false;
-  }
-
-  // Make the socket non-blocking. Connect, close, shutdown etc will not block
-  // the thread waiting for the socket operation to complete.
-  if (usrsctp_set_non_blocking(sock_, 1) < 0) {
-    LOG_ERRNO(LS_ERROR) << debug_name_ << "Failed to set SCTP to non blocking.";
-    return false;
-  }
-
-  // This ensures that the usrsctp close call deletes the association. This
-  // prevents usrsctp from calling OnSctpOutboundPacket with references to
-  // this class as the address.
-  linger linger_opt;
-  linger_opt.l_onoff = 1;
-  linger_opt.l_linger = 0;
-  if (usrsctp_setsockopt(sock_, SOL_SOCKET, SO_LINGER, &linger_opt,
-                         sizeof(linger_opt))) {
-    LOG_ERRNO(LS_ERROR) << debug_name_ << "Failed to set SO_LINGER.";
-    return false;
-  }
-
-  // Enable stream ID resets.
-  struct sctp_assoc_value stream_rst;
-  stream_rst.assoc_id = SCTP_ALL_ASSOC;
-  stream_rst.assoc_value = 1;
-  if (usrsctp_setsockopt(sock_, IPPROTO_SCTP, SCTP_ENABLE_STREAM_RESET,
-                         &stream_rst, sizeof(stream_rst))) {
-    LOG_ERRNO(LS_ERROR) << debug_name_
-                        << "Failed to set SCTP_ENABLE_STREAM_RESET.";
-    return false;
-  }
-
-  // Nagle.
-  uint32_t nodelay = 1;
-  if (usrsctp_setsockopt(sock_, IPPROTO_SCTP, SCTP_NODELAY, &nodelay,
-                         sizeof(nodelay))) {
-    LOG_ERRNO(LS_ERROR) << debug_name_ << "Failed to set SCTP_NODELAY.";
-    return false;
-  }
-
-  // Subscribe to SCTP event notifications.
-  int event_types[] = {SCTP_ASSOC_CHANGE,
-                       SCTP_PEER_ADDR_CHANGE,
-                       SCTP_SEND_FAILED_EVENT,
-                       SCTP_SENDER_DRY_EVENT,
-                       SCTP_STREAM_RESET_EVENT};
-  struct sctp_event event = {0};
-  event.se_assoc_id = SCTP_ALL_ASSOC;
-  event.se_on = 1;
-  for (size_t i = 0; i < arraysize(event_types); i++) {
-    event.se_type = event_types[i];
-    if (usrsctp_setsockopt(sock_, IPPROTO_SCTP, SCTP_EVENT, &event,
-                           sizeof(event)) < 0) {
-      LOG_ERRNO(LS_ERROR) << debug_name_ << "Failed to set SCTP_EVENT type: "
-                          << event.se_type;
-      return false;
-    }
-  }
-
-  // Register this class as an address for usrsctp. This is used by SCTP to
-  // direct the packets received (by the created socket) to this class.
-  usrsctp_register_address(this);
-  sending_ = true;
-  return true;
-}
-
-void SctpDataMediaChannel::CloseSctpSocket() {
-  sending_ = false;
-  if (sock_) {
-    // We assume that SO_LINGER option is set to close the association when
-    // close is called. This means that any pending packets in usrsctp will be
-    // discarded instead of being sent.
-    usrsctp_close(sock_);
-    sock_ = NULL;
-    usrsctp_deregister_address(this);
-
-    DecrementUsrSctpUsageCount();
-  }
-}
-
-bool SctpDataMediaChannel::Connect() {
-  LOG(LS_VERBOSE) << debug_name_ << "->Connect().";
-
-  // If we already have a socket connection, just return.
-  if (sock_) {
-    LOG(LS_WARNING) << debug_name_ << "->Connect(): Ignored as socket "
-                                      "is already established.";
-    return true;
-  }
-
-  // If no socket (it was closed) try to start it again. This can happen when
-  // the socket we are connecting to closes, does an sctp shutdown handshake,
-  // or behaves unexpectedly causing us to perform a CloseSctpSocket.
-  if (!sock_ && !OpenSctpSocket()) {
-    return false;
-  }
-
-  // Note: conversion from int to uint16_t happens on assignment.
-  sockaddr_conn local_sconn = GetSctpSockAddr(local_port_);
-  if (usrsctp_bind(sock_, reinterpret_cast<sockaddr *>(&local_sconn),
-                   sizeof(local_sconn)) < 0) {
-    LOG_ERRNO(LS_ERROR) << debug_name_ << "->Connect(): "
-                        << ("Failed usrsctp_bind");
-    CloseSctpSocket();
-    return false;
-  }
-
-  // Note: conversion from int to uint16_t happens on assignment.
-  sockaddr_conn remote_sconn = GetSctpSockAddr(remote_port_);
-  int connect_result = usrsctp_connect(
-      sock_, reinterpret_cast<sockaddr *>(&remote_sconn), sizeof(remote_sconn));
-  if (connect_result < 0 && errno != SCTP_EINPROGRESS) {
-    LOG_ERRNO(LS_ERROR) << debug_name_ << "Failed usrsctp_connect. got errno="
-                        << errno << ", but wanted " << SCTP_EINPROGRESS;
-    CloseSctpSocket();
-    return false;
-  }
-  // Set the MTU and disable MTU discovery.
-  // We can only do this after usrsctp_connect or it has no effect.
-  sctp_paddrparams params = {{0}};
-  memcpy(&params.spp_address, &remote_sconn, sizeof(remote_sconn));
-  params.spp_flags = SPP_PMTUD_DISABLE;
-  params.spp_pathmtu = kSctpMtu;
-  if (usrsctp_setsockopt(sock_, IPPROTO_SCTP, SCTP_PEER_ADDR_PARAMS, &params,
-                         sizeof(params))) {
-    LOG_ERRNO(LS_ERROR) << debug_name_
-                        << "Failed to set SCTP_PEER_ADDR_PARAMS.";
-  }
-  return true;
-}
-
-void SctpDataMediaChannel::Disconnect() {
-  // TODO(ldixon): Consider calling |usrsctp_shutdown(sock_, ...)| to do a
-  // shutdown handshake and remove the association.
-  CloseSctpSocket();
-}
-
-bool SctpDataMediaChannel::SetSend(bool send) {
-  if (!sending_ && send) {
-    return Connect();
-  }
-  if (sending_ && !send) {
-    Disconnect();
-  }
-  return true;
-}
-
-bool SctpDataMediaChannel::SetReceive(bool receive) {
-  receiving_ = receive;
-  return true;
-}
-
-bool SctpDataMediaChannel::SetSendParameters(const DataSendParameters& params) {
-  return SetSendCodecs(params.codecs);
-}
-
-bool SctpDataMediaChannel::SetRecvParameters(const DataRecvParameters& params) {
-  return SetRecvCodecs(params.codecs);
-}
-
-bool SctpDataMediaChannel::AddSendStream(const StreamParams& stream) {
-  return AddStream(stream);
-}
-
-bool SctpDataMediaChannel::RemoveSendStream(uint32_t ssrc) {
-  return ResetStream(ssrc);
-}
-
-bool SctpDataMediaChannel::AddRecvStream(const StreamParams& stream) {
-  // SCTP DataChannels are always bi-directional and calling AddSendStream will
-  // enable both sending and receiving on the stream. So AddRecvStream is a
-  // no-op.
-  return true;
-}
-
-bool SctpDataMediaChannel::RemoveRecvStream(uint32_t ssrc) {
-  // SCTP DataChannels are always bi-directional and calling RemoveSendStream
-  // will disable both sending and receiving on the stream. So RemoveRecvStream
-  // is a no-op.
-  return true;
-}
-
-bool SctpDataMediaChannel::SendData(
-    const SendDataParams& params,
-    const rtc::CopyOnWriteBuffer& payload,
-    SendDataResult* result) {
-  if (result) {
-    // Preset |result| to assume an error.  If SendData succeeds, we'll
-    // overwrite |*result| once more at the end.
-    *result = SDR_ERROR;
-  }
-
-  if (!sending_) {
-    LOG(LS_WARNING) << debug_name_ << "->SendData(...): "
-                    << "Not sending packet with ssrc=" << params.ssrc
-                    << " len=" << payload.size() << " before SetSend(true).";
-    return false;
-  }
-
-  if (params.type != DMT_CONTROL &&
-      open_streams_.find(params.ssrc) == open_streams_.end()) {
-    LOG(LS_WARNING) << debug_name_ << "->SendData(...): "
-                    << "Not sending data because ssrc is unknown: "
-                    << params.ssrc;
-    return false;
-  }
-
-  //
-  // Send data using SCTP.
-  ssize_t send_res = 0;  // result from usrsctp_sendv.
-  struct sctp_sendv_spa spa = {0};
-  spa.sendv_flags |= SCTP_SEND_SNDINFO_VALID;
-  spa.sendv_sndinfo.snd_sid = params.ssrc;
-  spa.sendv_sndinfo.snd_ppid = rtc::HostToNetwork32(
-      GetPpid(params.type));
-
-  // Ordered implies reliable.
-  if (!params.ordered) {
-    spa.sendv_sndinfo.snd_flags |= SCTP_UNORDERED;
-    if (params.max_rtx_count >= 0 || params.max_rtx_ms == 0) {
-      spa.sendv_flags |= SCTP_SEND_PRINFO_VALID;
-      spa.sendv_prinfo.pr_policy = SCTP_PR_SCTP_RTX;
-      spa.sendv_prinfo.pr_value = params.max_rtx_count;
-    } else {
-      spa.sendv_flags |= SCTP_SEND_PRINFO_VALID;
-      spa.sendv_prinfo.pr_policy = SCTP_PR_SCTP_TTL;
-      spa.sendv_prinfo.pr_value = params.max_rtx_ms;
-    }
-  }
-
-  // We don't fragment.
-  send_res = usrsctp_sendv(
-      sock_, payload.data(), static_cast<size_t>(payload.size()), NULL, 0, &spa,
-      rtc::checked_cast<socklen_t>(sizeof(spa)), SCTP_SENDV_SPA, 0);
-  if (send_res < 0) {
-    if (errno == SCTP_EWOULDBLOCK) {
-      *result = SDR_BLOCK;
-      LOG(LS_INFO) << debug_name_ << "->SendData(...): EWOULDBLOCK returned";
-    } else {
-      LOG_ERRNO(LS_ERROR) << "ERROR:" << debug_name_
-                          << "->SendData(...): "
-                          << " usrsctp_sendv: ";
-    }
-    return false;
-  }
-  if (result) {
-    // Only way out now is success.
-    *result = SDR_SUCCESS;
-  }
-  return true;
-}
-
-// Called by network interface when a packet has been received.
-void SctpDataMediaChannel::OnPacketReceived(
-    rtc::CopyOnWriteBuffer* packet, const rtc::PacketTime& packet_time) {
-  RTC_DCHECK(rtc::Thread::Current() == worker_thread_);
-  LOG(LS_VERBOSE) << debug_name_ << "->OnPacketReceived(...): "
-                  << " length=" << packet->size() << ", sending: " << sending_;
-  // Only give receiving packets to usrsctp after if connected. This enables two
-  // peers to each make a connect call, but for them not to receive an INIT
-  // packet before they have called connect; least the last receiver of the INIT
-  // packet will have called connect, and a connection will be established.
-  if (sending_) {
-    // Pass received packet to SCTP stack. Once processed by usrsctp, the data
-    // will be will be given to the global OnSctpInboundData, and then,
-    // marshalled by a Post and handled with OnMessage.
-    VerboseLogPacket(packet->cdata(), packet->size(), SCTP_DUMP_INBOUND);
-    usrsctp_conninput(this, packet->cdata(), packet->size(), 0);
-  } else {
-    // TODO(ldixon): Consider caching the packet for very slightly better
-    // reliability.
-  }
-}
-
-void SctpDataMediaChannel::OnInboundPacketFromSctpToChannel(
-    SctpInboundPacket* packet) {
-  LOG(LS_VERBOSE) << debug_name_ << "->OnInboundPacketFromSctpToChannel(...): "
-                  << "Received SCTP data:"
-                  << " ssrc=" << packet->params.ssrc
-                  << " notification: " << (packet->flags & MSG_NOTIFICATION)
-                  << " length=" << packet->buffer.size();
-  // Sending a packet with data == NULL (no data) is SCTPs "close the
-  // connection" message. This sets sock_ = NULL;
-  if (!packet->buffer.size() || !packet->buffer.data()) {
-    LOG(LS_INFO) << debug_name_ << "->OnInboundPacketFromSctpToChannel(...): "
-                                   "No data, closing.";
-    return;
-  }
-  if (packet->flags & MSG_NOTIFICATION) {
-    OnNotificationFromSctp(packet->buffer);
-  } else {
-    OnDataFromSctpToChannel(packet->params, packet->buffer);
-  }
-}
-
-void SctpDataMediaChannel::OnDataFromSctpToChannel(
-    const ReceiveDataParams& params, const rtc::CopyOnWriteBuffer& buffer) {
-  if (receiving_) {
-    LOG(LS_VERBOSE) << debug_name_ << "->OnDataFromSctpToChannel(...): "
-                    << "Posting with length: " << buffer.size()
-                    << " on stream " << params.ssrc;
-    // Reports all received messages to upper layers, no matter whether the sid
-    // is known.
-    SignalDataReceived(params, buffer.data<char>(), buffer.size());
-  } else {
-    LOG(LS_WARNING) << debug_name_ << "->OnDataFromSctpToChannel(...): "
-                    << "Not receiving packet with sid=" << params.ssrc
-                    << " len=" << buffer.size() << " before SetReceive(true).";
-  }
-}
-
-bool SctpDataMediaChannel::AddStream(const StreamParams& stream) {
-  if (!stream.has_ssrcs()) {
-    return false;
-  }
-
-  const uint32_t ssrc = stream.first_ssrc();
-  if (ssrc > kMaxSctpSid) {
-    LOG(LS_WARNING) << debug_name_ << "->Add(Send|Recv)Stream(...): "
-                    << "Not adding data stream '" << stream.id
-                    << "' with sid=" << ssrc << " because sid is too high.";
-    return false;
-  } else if (open_streams_.find(ssrc) != open_streams_.end()) {
-    LOG(LS_WARNING) << debug_name_ << "->Add(Send|Recv)Stream(...): "
-                    << "Not adding data stream '" << stream.id
-                    << "' with sid=" << ssrc
-                    << " because stream is already open.";
-    return false;
-  } else if (queued_reset_streams_.find(ssrc) != queued_reset_streams_.end()
-             || sent_reset_streams_.find(ssrc) != sent_reset_streams_.end()) {
-    LOG(LS_WARNING) << debug_name_ << "->Add(Send|Recv)Stream(...): "
-                    << "Not adding data stream '" << stream.id
-                    << "' with sid=" << ssrc
-                    << " because stream is still closing.";
-    return false;
-  }
-
-  open_streams_.insert(ssrc);
-  return true;
-}
-
-bool SctpDataMediaChannel::ResetStream(uint32_t ssrc) {
-  // We typically get this called twice for the same stream, once each for
-  // Send and Recv.
-  StreamSet::iterator found = open_streams_.find(ssrc);
-
-  if (found == open_streams_.end()) {
-    LOG(LS_VERBOSE) << debug_name_ << "->ResetStream(" << ssrc << "): "
-                    << "stream not found.";
-    return false;
-  } else {
-    LOG(LS_VERBOSE) << debug_name_ << "->ResetStream(" << ssrc << "): "
-                    << "Removing and queuing RE-CONFIG chunk.";
-    open_streams_.erase(found);
-  }
-
-  // SCTP won't let you have more than one stream reset pending at a time, but
-  // you can close multiple streams in a single reset.  So, we keep an internal
-  // queue of streams-to-reset, and send them as one reset message in
-  // SendQueuedStreamResets().
-  queued_reset_streams_.insert(ssrc);
-
-  // Signal our stream-reset logic that it should try to send now, if it can.
-  SendQueuedStreamResets();
-
-  // The stream will actually get removed when we get the acknowledgment.
-  return true;
-}
-
-void SctpDataMediaChannel::OnNotificationFromSctp(
-    const rtc::CopyOnWriteBuffer& buffer) {
-  const sctp_notification& notification =
-      reinterpret_cast<const sctp_notification&>(*buffer.data());
-  ASSERT(notification.sn_header.sn_length == buffer.size());
-
-  // TODO(ldixon): handle notifications appropriately.
-  switch (notification.sn_header.sn_type) {
-    case SCTP_ASSOC_CHANGE:
-      LOG(LS_VERBOSE) << "SCTP_ASSOC_CHANGE";
-      OnNotificationAssocChange(notification.sn_assoc_change);
-      break;
-    case SCTP_REMOTE_ERROR:
-      LOG(LS_INFO) << "SCTP_REMOTE_ERROR";
-      break;
-    case SCTP_SHUTDOWN_EVENT:
-      LOG(LS_INFO) << "SCTP_SHUTDOWN_EVENT";
-      break;
-    case SCTP_ADAPTATION_INDICATION:
-      LOG(LS_INFO) << "SCTP_ADAPTATION_INDICATION";
-      break;
-    case SCTP_PARTIAL_DELIVERY_EVENT:
-      LOG(LS_INFO) << "SCTP_PARTIAL_DELIVERY_EVENT";
-      break;
-    case SCTP_AUTHENTICATION_EVENT:
-      LOG(LS_INFO) << "SCTP_AUTHENTICATION_EVENT";
-      break;
-    case SCTP_SENDER_DRY_EVENT:
-      LOG(LS_VERBOSE) << "SCTP_SENDER_DRY_EVENT";
-      SignalReadyToSend(true);
-      break;
-    // TODO(ldixon): Unblock after congestion.
-    case SCTP_NOTIFICATIONS_STOPPED_EVENT:
-      LOG(LS_INFO) << "SCTP_NOTIFICATIONS_STOPPED_EVENT";
-      break;
-    case SCTP_SEND_FAILED_EVENT:
-      LOG(LS_INFO) << "SCTP_SEND_FAILED_EVENT";
-      break;
-    case SCTP_STREAM_RESET_EVENT:
-      OnStreamResetEvent(&notification.sn_strreset_event);
-      break;
-    case SCTP_ASSOC_RESET_EVENT:
-      LOG(LS_INFO) << "SCTP_ASSOC_RESET_EVENT";
-      break;
-    case SCTP_STREAM_CHANGE_EVENT:
-      LOG(LS_INFO) << "SCTP_STREAM_CHANGE_EVENT";
-      // An acknowledgment we get after our stream resets have gone through,
-      // if they've failed.  We log the message, but don't react -- we don't
-      // keep around the last-transmitted set of SSIDs we wanted to close for
-      // error recovery.  It doesn't seem likely to occur, and if so, likely
-      // harmless within the lifetime of a single SCTP association.
-      break;
-    default:
-      LOG(LS_WARNING) << "Unknown SCTP event: "
-                      << notification.sn_header.sn_type;
-      break;
-  }
-}
-
-void SctpDataMediaChannel::OnNotificationAssocChange(
-    const sctp_assoc_change& change) {
-  switch (change.sac_state) {
-    case SCTP_COMM_UP:
-      LOG(LS_VERBOSE) << "Association change SCTP_COMM_UP";
-      break;
-    case SCTP_COMM_LOST:
-      LOG(LS_INFO) << "Association change SCTP_COMM_LOST";
-      break;
-    case SCTP_RESTART:
-      LOG(LS_INFO) << "Association change SCTP_RESTART";
-      break;
-    case SCTP_SHUTDOWN_COMP:
-      LOG(LS_INFO) << "Association change SCTP_SHUTDOWN_COMP";
-      break;
-    case SCTP_CANT_STR_ASSOC:
-      LOG(LS_INFO) << "Association change SCTP_CANT_STR_ASSOC";
-      break;
-    default:
-      LOG(LS_INFO) << "Association change UNKNOWN";
-      break;
-  }
-}
-
-void SctpDataMediaChannel::OnStreamResetEvent(
-    const struct sctp_stream_reset_event* evt) {
-  // A stream reset always involves two RE-CONFIG chunks for us -- we always
-  // simultaneously reset a sid's sequence number in both directions.  The
-  // requesting side transmits a RE-CONFIG chunk and waits for the peer to send
-  // one back.  Both sides get this SCTP_STREAM_RESET_EVENT when they receive
-  // RE-CONFIGs.
-  const int num_ssrcs = (evt->strreset_length - sizeof(*evt)) /
-      sizeof(evt->strreset_stream_list[0]);
-  LOG(LS_VERBOSE) << "SCTP_STREAM_RESET_EVENT(" << debug_name_
-                  << "): Flags = 0x"
-                  << std::hex << evt->strreset_flags << " ("
-                  << ListFlags(evt->strreset_flags) << ")";
-  LOG(LS_VERBOSE) << "Assoc = " << evt->strreset_assoc_id << ", Streams = ["
-                  << ListArray(evt->strreset_stream_list, num_ssrcs)
-                  << "], Open: ["
-                  << ListStreams(open_streams_) << "], Q'd: ["
-                  << ListStreams(queued_reset_streams_) << "], Sent: ["
-                  << ListStreams(sent_reset_streams_) << "]";
-
-  // If both sides try to reset some streams at the same time (even if they're
-  // disjoint sets), we can get reset failures.
-  if (evt->strreset_flags & SCTP_STREAM_RESET_FAILED) {
-    // OK, just try again.  The stream IDs sent over when the RESET_FAILED flag
-    // is set seem to be garbage values.  Ignore them.
-    queued_reset_streams_.insert(
-        sent_reset_streams_.begin(),
-        sent_reset_streams_.end());
-    sent_reset_streams_.clear();
-
-  } else if (evt->strreset_flags & SCTP_STREAM_RESET_INCOMING_SSN) {
-    // Each side gets an event for each direction of a stream.  That is,
-    // closing sid k will make each side receive INCOMING and OUTGOING reset
-    // events for k.  As per RFC6525, Section 5, paragraph 2, each side will
-    // get an INCOMING event first.
-    for (int i = 0; i < num_ssrcs; i++) {
-      const int stream_id = evt->strreset_stream_list[i];
-
-      // See if this stream ID was closed by our peer or ourselves.
-      StreamSet::iterator it = sent_reset_streams_.find(stream_id);
-
-      // The reset was requested locally.
-      if (it != sent_reset_streams_.end()) {
-        LOG(LS_VERBOSE) << "SCTP_STREAM_RESET_EVENT(" << debug_name_
-                        << "): local sid " << stream_id << " acknowledged.";
-        sent_reset_streams_.erase(it);
-
-      } else if ((it = open_streams_.find(stream_id))
-                 != open_streams_.end()) {
-        // The peer requested the reset.
-        LOG(LS_VERBOSE) << "SCTP_STREAM_RESET_EVENT(" << debug_name_
-                        << "): closing sid " << stream_id;
-        open_streams_.erase(it);
-        SignalStreamClosedRemotely(stream_id);
-
-      } else if ((it = queued_reset_streams_.find(stream_id))
-                 != queued_reset_streams_.end()) {
-        // The peer requested the reset, but there was a local reset
-        // queued.
-        LOG(LS_VERBOSE) << "SCTP_STREAM_RESET_EVENT(" << debug_name_
-                        << "): double-sided close for sid " << stream_id;
-        // Both sides want the stream closed, and the peer got to send the
-        // RE-CONFIG first.  Treat it like the local Remove(Send|Recv)Stream
-        // finished quickly.
-        queued_reset_streams_.erase(it);
-
-      } else {
-        // This stream is unknown.  Sometimes this can be from an
-        // RESET_FAILED-related retransmit.
-        LOG(LS_VERBOSE) << "SCTP_STREAM_RESET_EVENT(" << debug_name_
-                        << "): Unknown sid " << stream_id;
-      }
-    }
-  }
-
-  // Always try to send the queued RESET because this call indicates that the
-  // last local RESET or remote RESET has made some progress.
-  SendQueuedStreamResets();
-}
-
-// Puts the specified |param| from the codec identified by |id| into |dest|
-// and returns true.  Or returns false if it wasn't there, leaving |dest|
-// untouched.
-static bool GetCodecIntParameter(const std::vector<DataCodec>& codecs,
-                                 int id, const std::string& name,
-                                 const std::string& param, int* dest) {
-  std::string value;
-  DataCodec match_pattern(id, name);
-  for (size_t i = 0; i < codecs.size(); ++i) {
-    if (codecs[i].Matches(match_pattern)) {
-      if (codecs[i].GetParam(param, &value)) {
-        *dest = rtc::FromString<int>(value);
-        return true;
-      }
-    }
-  }
-  return false;
-}
-
-bool SctpDataMediaChannel::SetSendCodecs(const std::vector<DataCodec>& codecs) {
-  return GetCodecIntParameter(
-      codecs, kGoogleSctpDataCodecPlType, kGoogleSctpDataCodecName,
-      kCodecParamPort, &remote_port_);
-}
-
-bool SctpDataMediaChannel::SetRecvCodecs(const std::vector<DataCodec>& codecs) {
-  return GetCodecIntParameter(
-      codecs, kGoogleSctpDataCodecPlType, kGoogleSctpDataCodecName,
-      kCodecParamPort, &local_port_);
-}
-
-void SctpDataMediaChannel::OnPacketFromSctpToNetwork(
-    rtc::CopyOnWriteBuffer* buffer) {
-  if (buffer->size() > (kSctpMtu)) {
-    LOG(LS_ERROR) << debug_name_ << "->OnPacketFromSctpToNetwork(...): "
-                  << "SCTP seems to have made a packet that is bigger "
-                  << "than its official MTU: " << buffer->size()
-                  << " vs max of " << kSctpMtu;
-  }
-  MediaChannel::SendPacket(buffer, rtc::PacketOptions());
-}
-
-bool SctpDataMediaChannel::SendQueuedStreamResets() {
-  if (!sent_reset_streams_.empty() || queued_reset_streams_.empty()) {
-    return true;
-  }
-
-  LOG(LS_VERBOSE) << "SendQueuedStreamResets[" << debug_name_ << "]: Sending ["
-                  << ListStreams(queued_reset_streams_) << "], Open: ["
-                  << ListStreams(open_streams_) << "], Sent: ["
-                  << ListStreams(sent_reset_streams_) << "]";
-
-  const size_t num_streams = queued_reset_streams_.size();
-  const size_t num_bytes =
-      sizeof(struct sctp_reset_streams) + (num_streams * sizeof(uint16_t));
-
-  std::vector<uint8_t> reset_stream_buf(num_bytes, 0);
-  struct sctp_reset_streams* resetp = reinterpret_cast<sctp_reset_streams*>(
-      &reset_stream_buf[0]);
-  resetp->srs_assoc_id = SCTP_ALL_ASSOC;
-  resetp->srs_flags = SCTP_STREAM_RESET_INCOMING | SCTP_STREAM_RESET_OUTGOING;
-  resetp->srs_number_streams = rtc::checked_cast<uint16_t>(num_streams);
-  int result_idx = 0;
-  for (StreamSet::iterator it = queued_reset_streams_.begin();
-       it != queued_reset_streams_.end(); ++it) {
-    resetp->srs_stream_list[result_idx++] = *it;
-  }
-
-  int ret = usrsctp_setsockopt(
-      sock_, IPPROTO_SCTP, SCTP_RESET_STREAMS, resetp,
-      rtc::checked_cast<socklen_t>(reset_stream_buf.size()));
-  if (ret < 0) {
-    LOG_ERRNO(LS_ERROR) << debug_name_ << "Failed to send a stream reset for "
-                        << num_streams << " streams";
-    return false;
-  }
-
-  // sent_reset_streams_ is empty, and all the queued_reset_streams_ go into
-  // it now.
-  queued_reset_streams_.swap(sent_reset_streams_);
-  return true;
-}
-
-void SctpDataMediaChannel::OnMessage(rtc::Message* msg) {
-  switch (msg->message_id) {
-    case MSG_SCTPINBOUNDPACKET: {
-      std::unique_ptr<InboundPacketMessage> pdata(
-          static_cast<InboundPacketMessage*>(msg->pdata));
-      OnInboundPacketFromSctpToChannel(pdata->data().get());
-      break;
-    }
-    case MSG_SCTPOUTBOUNDPACKET: {
-      std::unique_ptr<OutboundPacketMessage> pdata(
-          static_cast<OutboundPacketMessage*>(msg->pdata));
-      OnPacketFromSctpToNetwork(pdata->data().get());
-      break;
-    }
-  }
-}
-}  // namespace cricket