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htuch merged 4 commits into from
Feb 15, 2018
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ssl: fix handshake hang that manifested on OS X. #2624

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ssl: fix handshake hang that manifested on OS X.
htuch Feb 15, 2018
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htuch Feb 15, 2018
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htuch Feb 15, 2018
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htuch Feb 15, 2018
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9 changes: 9 additions & 0 deletions source/common/network/connection_impl.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -275,6 +275,15 @@ void ConnectionImpl::raiseEvent(ConnectionEvent event) {
// connected events.
callback->onEvent(event);
}
// We may have pending data in the write buffer on transport handshake
// completion, which may also have completed in the context of onReadReady(),
// where no check of the write buffer is made. Provide an opportunity to flush
// here. If connection write is not ready, this is harmless. We should only do
// this if we're still open (the above callbacks may have closed).
if (state() == State::Open && event == ConnectionEvent::Connected &&
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@mattklein123 mattklein123 Feb 18, 2018

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@htuch @ggreenway I'm late here, but I think it's slightly strange that in the plaintext case we effectively recurse into onWriteReady() which already handles this case by trying to write after a connection happens. Did we consider any other variant of this change? It's not a big deal just curious.

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@ggreenway ggreenway Feb 19, 2018

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That is weird; I didn't catch that. No, we didn't try anything else. We should look into if there's a better way to handle this. It seems to work, but it is strange, and hard to reason about.

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@htuch htuch Feb 19, 2018

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It works because we flip connecting_ status before re-entry. I agree this is harder to reason about than would be ideal. Should we just return unconditionally in raw buffer socket onWriteReady() following a new connection and defer to the new write check?

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@mattklein123 mattklein123 Feb 21, 2018

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@htuch agreed the code works as is. To make it clearer yes I would either return unconditionally with a comment here https://github.com/envoyproxy/envoy/blob/master/source/common/network/connection_impl.cc#L477 or another option is to factor out the 2nd part of onWriteReady() into a separate function and call that in the SSL case when handshake completes during a read callback. I think the former is simpler IMO.

write_buffer_->length() > 0) {
onWriteReady();
}
}

bool ConnectionImpl::readEnabled() const { return read_enabled_; }
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34 changes: 33 additions & 1 deletion test/common/network/connection_impl_test.cc
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Expand Up @@ -842,6 +842,10 @@ class MockTransportConnectionImplTest : public testing::Test {
EXPECT_CALL(dispatcher_, createFileEvent_(0, _, _, _))
.WillOnce(DoAll(SaveArg<1>(&file_ready_cb_), Return(file_event_)));
transport_socket_ = new NiceMock<MockTransportSocket>;
EXPECT_CALL(*transport_socket_, setTransportSocketCallbacks(_))
.WillOnce(Invoke([this](TransportSocketCallbacks& callbacks) {
transport_socket_callbacks_ = &callbacks;
}));
connection_.reset(
new ConnectionImpl(dispatcher_, std::make_unique<ConnectionSocketImpl>(0, nullptr, nullptr),
TransportSocketPtr(transport_socket_), true));
Expand All @@ -861,9 +865,10 @@ class MockTransportConnectionImplTest : public testing::Test {
std::unique_ptr<ConnectionImpl> connection_;
Event::MockDispatcher dispatcher_;
NiceMock<MockConnectionCallbacks> callbacks_;
NiceMock<MockTransportSocket>* transport_socket_;
MockTransportSocket* transport_socket_;
Event::MockFileEvent* file_event_;
Event::FileReadyCb file_ready_cb_;
TransportSocketCallbacks* transport_socket_callbacks_;
};

// Test that BytesSentCb is invoked at the correct times
Expand Down Expand Up @@ -1122,6 +1127,33 @@ TEST_F(MockTransportConnectionImplTest, WriteEndStreamStopIteration) {
connection_->write(buffer, true);
}

// Validate that when the transport signals ConnectionEvent::Connected, that we
// check for pending write buffer content.
TEST_F(MockTransportConnectionImplTest, WriteReadyOnConnected) {
InSequence s;

// Queue up some data in write buffer, simulating what happens in SSL handshake.
const std::string val("some data");
Buffer::OwnedImpl buffer(val);
EXPECT_CALL(*file_event_, activate(Event::FileReadyType::Write)).WillOnce(Invoke(file_ready_cb_));
EXPECT_CALL(*transport_socket_, doWrite(BufferStringEqual(val), false))
.WillOnce(Return(IoResult{PostIoAction::KeepOpen, 0, false}));
connection_->write(buffer, false);

// A read event happens, resulting in handshake completion and
// raiseEvent(Network::ConnectionEvent::Connected). Since we have data queued
// in the write buffer, we should see a doWrite with this data.
EXPECT_CALL(*transport_socket_, doRead(_)).WillOnce(InvokeWithoutArgs([this] {
transport_socket_callbacks_->raiseEvent(Network::ConnectionEvent::Connected);
return IoResult{PostIoAction::KeepOpen, 0, false};
}));
EXPECT_CALL(*transport_socket_, doWrite(BufferStringEqual(val), false))
.WillOnce(Return(IoResult{PostIoAction::KeepOpen, 0, false}));
file_ready_cb_(Event::FileReadyType::Read);
EXPECT_CALL(*transport_socket_, doWrite(_, true))
.WillOnce(Return(IoResult{PostIoAction::KeepOpen, 0, true}));
}

class ReadBufferLimitTest : public ConnectionImplTest {
public:
void readBufferLimitTest(uint32_t read_buffer_limit, uint32_t expected_chunk_size) {
Expand Down