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Avoid duplicate usrsctp_init if the last usrsctp_finish failed.

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When deinitializing usrsctp, we attempt to call usrsctp_finish in a loop
for three seconds (it may fail because another sctp thread is holding a
reference to something). If the three seconds run out, usrsctp is left
in a still initialized state, and bad things happen down the road if
usrsctp_init is called in the state.

Bug: chromium:1138878
Change-Id: I9c24d51d5a274b06bdf4183261694fc2989136c5
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/189940
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Taylor <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32467}
This commit is contained in:
Taylor Brandstetter 2020-10-20 17:33:03 -07:00 committed by Commit Bot
parent 236a89b659
commit 4182b499b3
1 changed files with 15 additions and 3 deletions
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18
media/sctp/sctp_transport.cc
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@ -58,6 +58,7 @@ static constexpr size_t kSctpMtu = 1200;
// Set the initial value of the static SCTP Data Engines reference count.
ABSL_CONST_INIT int g_usrsctp_usage_count = 0;
ABSL_CONST_INIT bool g_usrsctp_initialized_ = false;
ABSL_CONST_INIT webrtc::GlobalMutex g_usrsctp_lock_(absl::kConstInit);
// DataMessageType is used for the SCTP "Payload Protocol Identifier", as
@ -262,9 +263,19 @@ class SctpTransport::UsrSctpWrapper {
public:
static void InitializeUsrSctp() {
RTC_LOG(LS_INFO) << __FUNCTION__;
// First argument is udp_encapsulation_port, which is not releveant for our
// AF_CONN use of sctp.
usrsctp_init(0, &UsrSctpWrapper::OnSctpOutboundPacket, &DebugSctpPrintf);
// UninitializeUsrSctp tries to call usrsctp_finish in a loop for three
// seconds; if that failed and we were left in a still-initialized state, we
// don't want to call usrsctp_init again as that will result in undefined
// behavior.
if (g_usrsctp_initialized_) {
RTC_LOG(LS_WARNING) << "Not reinitializing usrsctp since last attempt at "
"usrsctp_finish failed.";
} else {
// First argument is udp_encapsulation_port, which is not releveant for
// our AF_CONN use of sctp.
usrsctp_init(0, &UsrSctpWrapper::OnSctpOutboundPacket, &DebugSctpPrintf);
g_usrsctp_initialized_ = true;
}
// To turn on/off detailed SCTP debugging. You will also need to have the
// SCTP_DEBUG cpp defines flag, which can be turned on in media/BUILD.gn.
@ -317,6 +328,7 @@ class SctpTransport::UsrSctpWrapper {
// 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) {
g_usrsctp_initialized_ = false;
delete g_transport_map_;
g_transport_map_ = nullptr;
return;