Added send-thresholding and fixed text packet dumping.

talk/media/sctp/sctpdataengine.cc

 /*
  * libjingle
  * Copyright 2012 Google Inc. and Robin Seggelmann
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 159 matching lines @@
     case SctpDataMediaChannel::PPID_NONE:
       *dest = cricket::DMT_NONE;
       return true;
 
     default:
       return false;
   }
 }
 
 // Log the packet in text2pcap format, if log level is at LS_VERBOSE.
-static void VerboseLogPacket(void *addr, size_t length, int direction) {
+static void VerboseLogPacket(void *data, size_t length, int direction) {
   if (LOG_CHECK_LEVEL(LS_VERBOSE) && length > 0) {
     char *dump_buf;
     if ((dump_buf = usrsctp_dumppacket(
-             addr, length, direction)) != NULL) {
+             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.
 static 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(addr, length, SCTP_DUMP_OUTBOUND);
+  VerboseLogPacket(data, length, SCTP_DUMP_OUTBOUND);
   // Note: We have to copy the data; the caller will delete it.
   auto* msg = new OutboundPacketMessage(
       new rtc::Buffer(reinterpret_cast<uint8_t*>(data), length));
   channel->worker_thread()->Post(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
@@ skipping 96 matching lines @@
 }
 
 DataMediaChannel* SctpDataEngine::CreateChannel(
     DataChannelType data_channel_type) {
   if (data_channel_type != DCT_SCTP) {
     return NULL;
   }
   return new SctpDataMediaChannel(rtc::Thread::Current());
 }
 
+// Our registrar of sockets to their channels.  Used for callbacks.
+SctpDataMediaChannel::SocketChannelMap SctpDataMediaChannel::sock_channel_map_;
+
 SctpDataMediaChannel::SctpDataMediaChannel(rtc::Thread* thread)
     : worker_thread_(thread),
       local_port_(kSctpDefaultPort),
       remote_port_(kSctpDefaultPort),
       sock_(NULL),
       sending_(false),
       receiving_(false),
       debug_name_("SctpDataMediaChannel") {
 }
 
 SctpDataMediaChannel::~SctpDataMediaChannel() {
   CloseSctpSocket();
 }
 
 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;
 }
 
+// static
+int SctpDataMediaChannel::SendThresholdCallback(struct socket* sock,

[pthatcher1, 2015/08/05 21:42:55]

I think it would make more sense to put this callback on the engine as a
non-static method.  

[lally1, 2015/08/18 20:38:56]

I don't know where I'd get an instance pointer.

[pthatcher1, 2015/08/18 21:51:52]

The instance pointer to the engine?  Could you use rtc::Bind to get a callback
that has a pointer to the engine?

+                                                uint32_t sb_free) {

[pthatcher1, 2015/08/05 21:42:55]

No ulp_info, like with reading a packet?  That's lame.

[lally1, 2015/08/18 20:38:56]

Yeah, that's the real issue here.  I had a prior version of this CL that used
usrsctp_getladdrs(sock,..)+usrsctp_freeladdrs to get the full sockaddr_conn, but
that's a full malloc/free cycle.

+  SocketChannelMap::iterator it = sock_channel_map_.find(sock);

[pthatcher1, 2015/08/05 21:42:55]

You can use 

auto it = sock_channel_map_.find(sock);


And then you don't need to have the SocketChannelMap typedef.

[lally1, 2015/08/18 20:38:56]

Thanks!

+  if (it == sock_channel_map_.end()) {

[pthatcher1, 2015/08/05 21:42:55]

Since there are almost always a very low number of SctpDataMediaChannels at one
time (1 or 2), it would be usually be more efficient and perhaps easier to
manager to just iterate over a vector of channels to find the one that has the
matching socket.

[lally1, 2015/08/18 20:38:56]

Done.

+    // Socket is in the process of shutdown.
+    LOG(LS_ERROR) << "Failed to get SctpDataMediaChannel for socket " << sock;
+    return 0;
+  }
+
+  it->second->SignalReadyToSend(true);
+  return 0;
+}
+
 bool SctpDataMediaChannel::OpenSctpSocket() {
   if (sock_) {
     LOG(LS_VERBOSE) << debug_name_
                     << "->Ignoring attempt to re-create existing socket.";
     return false;
   }
+
+  const int send_threshold = usrsctp_sysctl_get_sctp_sendspace() / 2;
+
   sock_ = usrsctp_socket(AF_CONN, SOCK_STREAM, IPPROTO_SCTP,
-                         cricket::OnSctpInboundPacket, NULL, 0, this);
+                         cricket::OnSctpInboundPacket,
+                         &SctpDataMediaChannel::SendThresholdCallback,
+                         send_threshold, this);
   if (!sock_) {
     LOG_ERRNO(LS_ERROR) << debug_name_ << "Failed to create SCTP socket.";
     return false;
   }
 
+  sock_channel_map_[sock_] = this;
+
   // 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.
@@ skipping 19 matching lines @@
 
   // 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;
   }
 
   // Disable MTU discovery
-  struct sctp_paddrparams params = {{0}};
+  struct sctp_paddrparams params;
+  memset(&params, 0, sizeof(params));
   params.spp_assoc_id = 0;
   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 false;
   }
 
@@ skipping 23 matching lines @@
   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_);
+    SocketChannelMap::iterator it = sock_channel_map_.find(sock_);
+    if (it != sock_channel_map_.end()) {
+      sock_channel_map_.erase(it);
+    } else {
+      LOG(LS_ERROR) << "CloseSctpSocket: the socket wasn't registered.";
+    }

[pthatcher1, 2015/08/05 21:42:55]

I think this works, and it shorter and only does one lookup:

if (!sock_channel_map_.erase(sock_)) {
  LOG(LS_ERROR) << "CloseSctpSocket: the socket wasn't registered.";
}

[lally1, 2015/08/18 20:38:56]

Thanks.  Moved above into ~SctpDataMediaChannel(), but as it's a vector<>, we
can't use this form of erase().

     sock_ = NULL;
     usrsctp_deregister_address(this);
   }
 }
 
 bool SctpDataMediaChannel::Connect() {
   LOG(LS_VERBOSE) << debug_name_ << "->Connect().";
 
   // If we already have a socket connection, just return.
   if (sock_) {
@@ skipping 447 matching lines @@
 }
 
 bool SctpDataMediaChannel::SetRecvCodecs(const std::vector<DataCodec>& codecs) {
   return GetCodecIntParameter(
       codecs, kGoogleSctpDataCodecId, kGoogleSctpDataCodecName, kCodecParamPort,
       &local_port_);
 }
 
 void SctpDataMediaChannel::OnPacketFromSctpToNetwork(
     rtc::Buffer* buffer) {
-  if (buffer->size() > kSctpMtu) {
+  // this is completely made up.
+  const int kSctpOverhead = 76;

[pthatcher1, 2015/08/05 21:42:55]

This could use a little more documentation, even if to explain why it can't be
0.  

[lally1, 2015/08/18 20:38:56]

Done.

+  if (buffer->size() > (kSctpOverhead + kSctpMtu)) {
     LOG(LS_ERROR) << debug_name_ << "->OnPacketFromSctpToNetwork(...): "
                   << "SCTP seems to have made a packet that is bigger "
-                     "than its official MTU.";
+                  << "than its official MTU: " << buffer->size()
+                  << " vs max of " << kSctpMtu;

[pthatcher1, 2015/08/05 21:42:55]

Should probably include something like "assuming X bytes of SCTP overhead".

[lally1, 2015/08/18 20:38:56]

Done.

   }
   MediaChannel::SendPacket(buffer);
 }
 
 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: ["
@@ skipping 41 matching lines @@
     }
     case MSG_SCTPOUTBOUNDPACKET: {
       rtc::scoped_ptr<OutboundPacketMessage> pdata(
           static_cast<OutboundPacketMessage*>(msg->pdata));
       OnPacketFromSctpToNetwork(pdata->data().get());
       break;
     }
   }
 }
 }  // namespace cricket