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Fix setting the MTU for SCTP.

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It was being set at the wrong point in time and with the address
parameter missing, so it wasn't having any effect.

Review-Url: https://codereview.webrtc.org/2237073002
Cr-Commit-Position: refs/heads/master@{#13909}
This commit is contained in:
deadbeef 2016-08-24 16:26:55 -07:00 committed by Commit bot
parent b60a8198f1
commit fe8f48962a
1 changed files with 17 additions and 23 deletions
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40
webrtc/media/sctp/sctpdataengine.cc
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@ -29,12 +29,12 @@
#include "webrtc/media/base/streamparams.h"
namespace cricket {
// The biggest SCTP packet. Starting from a 'safe' wire MTU value of 1280,
// The biggest SCTP packet. Starting from a 'safe' wire MTU value of 1280,
// take off 80 bytes for DTLS/TURN/TCP/IP overhead.
static const size_t kSctpMtu = 1200;
static constexpr size_t kSctpMtu = 1200;
// The size of the SCTP association send buffer. 256kB, the usrsctp default.
static const int kSendBufferSize = 262144;
static constexpr int kSendBufferSize = 262144;
struct SctpInboundPacket {
rtc::CopyOnWriteBuffer buffer;
@ -470,18 +470,6 @@ bool SctpDataMediaChannel::OpenSctpSocket() {
return false;
}
// Disable MTU discovery
sctp_paddrparams params = {{0}};
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;
}
// Subscribe to SCTP event notifications.
int event_types[] = {SCTP_ASSOC_CHANGE,
SCTP_PEER_ADDR_CHANGE,
@ -559,6 +547,18 @@ bool SctpDataMediaChannel::Connect() {
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(reinterpret_cast<sockaddr*>(&params.spp_address),
reinterpret_cast<sockaddr*>(&remote_sconn), sizeof(sockaddr));
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;
}
@ -998,17 +998,11 @@ bool SctpDataMediaChannel::SetRecvCodecs(const std::vector<DataCodec>& codecs) {
void SctpDataMediaChannel::OnPacketFromSctpToNetwork(
rtc::CopyOnWriteBuffer* buffer) {
// usrsctp seems to interpret the MTU we give it strangely -- it seems to
// give us back packets bigger than that MTU, if only by a fixed amount.
// This is that amount that we've observed.
const int kSctpOverhead = 76;
if (buffer->size() > (kSctpOverhead + kSctpMtu)) {
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
<< " even after adding " << kSctpOverhead
<< " extra SCTP overhead";
<< " vs max of " << kSctpMtu;
}
MediaChannel::SendPacket(buffer, rtc::PacketOptions());
}