gvisor.dev/gvisor@v0.0.0-20240520182842-f9d4d51c7e0f/test/syscalls/linux/socket_ip_tcp_generic.cc

// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "test/syscalls/linux/socket_ip_tcp_generic.h"

#include <fcntl.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <poll.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>

#include "gtest/gtest.h"
#include "absl/memory/memory.h"
#include "absl/time/clock.h"
#include "absl/time/time.h"
#include "test/util/save_util.h"
#include "test/util/socket_util.h"
#include "test/util/temp_path.h"
#include "test/util/test_util.h"
#include "test/util/thread_util.h"

namespace gvisor {
namespace testing {

using ::testing::AnyOf;
using ::testing::Eq;

TEST_P(TCPSocketPairTest, TcpInfoSucceeds) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  struct tcp_info opt = {};
  socklen_t optLen = sizeof(opt);
  EXPECT_THAT(getsockopt(sockets->first_fd(), SOL_TCP, TCP_INFO, &opt, &optLen),
              SyscallSucceeds());
}

TEST_P(TCPSocketPairTest, ShortTcpInfoSucceeds) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  struct tcp_info opt = {};
  socklen_t optLen = 1;
  EXPECT_THAT(getsockopt(sockets->first_fd(), SOL_TCP, TCP_INFO, &opt, &optLen),
              SyscallSucceeds());
}

TEST_P(TCPSocketPairTest, ZeroTcpInfoSucceeds) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  struct tcp_info opt = {};
  socklen_t optLen = 0;
  EXPECT_THAT(getsockopt(sockets->first_fd(), SOL_TCP, TCP_INFO, &opt, &optLen),
              SyscallSucceeds());
}

// Copied from include/net/tcp.h.
constexpr int TCP_CA_OPEN = 0;

TEST_P(TCPSocketPairTest, CheckTcpInfoFields) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char buf[10] = {};
  ASSERT_THAT(RetryEINTR(send)(sockets->first_fd(), buf, sizeof(buf), 0),
              SyscallSucceedsWithValue(sizeof(buf)));

  // Wait until second_fd sees the data and then recv it.
  struct pollfd poll_fd = {sockets->second_fd(), POLLIN, 0};
  constexpr int kPollTimeoutMs = 2000;  // Wait up to 2 seconds for the data.
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  ASSERT_THAT(RetryEINTR(recv)(sockets->second_fd(), buf, sizeof(buf), 0),
              SyscallSucceedsWithValue(sizeof(buf)));

  struct tcp_info opt = {};
  socklen_t optLen = sizeof(opt);
  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_TCP, TCP_INFO, &opt, &optLen),
              SyscallSucceeds());
  ASSERT_EQ(optLen, sizeof(opt));

  // Validates the received tcp_info fields.
  EXPECT_EQ(opt.tcpi_ca_state, TCP_CA_OPEN);
  EXPECT_GT(opt.tcpi_snd_cwnd, 0);
  EXPECT_GT(opt.tcpi_rto, 0);
}

// This test validates that an RST is sent instead of a FIN when data is
// unread on calls to close(2).
TEST_P(TCPSocketPairTest, RSTSentOnCloseWithUnreadData) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char buf[10] = {};
  ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));

  // Wait until t_ sees the data on its side but don't read it.
  struct pollfd poll_fd = {sockets->second_fd(), POLLIN | POLLHUP, 0};
  constexpr int kPollTimeoutMs = 20000;  // Wait up to 20 seconds for the data.
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  // Now close the connected without reading the data.
  ASSERT_THAT(close(sockets->release_second_fd()), SyscallSucceeds());

  // Wait for the other end to receive the RST (up to 20 seconds).
  struct pollfd poll_fd2 = {sockets->first_fd(), POLLIN | POLLHUP, 0};
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd2, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  // A shutdown with unread data will cause a RST to be sent instead
  // of a FIN, per RFC 2525 section 2.17; this is also what Linux does.
  ASSERT_THAT(RetryEINTR(read)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallFailsWithErrno(ECONNRESET));
}

// This test will validate that a RST will cause POLLHUP to trigger.
TEST_P(TCPSocketPairTest, RSTCausesPollHUP) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char buf[10] = {};
  ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));

  // Wait until second sees the data on its side but don't read it.
  struct pollfd poll_fd = {sockets->second_fd(), POLLIN, 0};
  constexpr int kPollTimeoutMs = 20000;  // Wait up to 20 seconds for the data.
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));
  EXPECT_EQ(poll_fd.revents & POLLIN, POLLIN);

  // Confirm we at least have one unread byte.
  int bytes_available = 0;
  ASSERT_THAT(RetryEINTR([&]() {
                return ioctl(sockets->second_fd(), FIONREAD, &bytes_available);
              })(),
              SyscallSucceeds());
  EXPECT_GT(bytes_available, 0);

  // Now close the connected socket without reading the data from the second,
  // this will cause a RST and we should see that with POLLHUP.
  ASSERT_THAT(close(sockets->release_second_fd()), SyscallSucceeds());

  // Wait for the other end to receive the RST (up to 20 seconds).
  struct pollfd poll_fd3 = {sockets->first_fd(), POLLHUP, 0};
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd3, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));
  ASSERT_NE(poll_fd3.revents & POLLHUP, 0);
}

// This test validates that even if a RST is sent the other end will not
// get an ECONNRESET until it's read all data.
TEST_P(TCPSocketPairTest, RSTSentOnCloseWithUnreadDataAllowsReadBuffered) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char buf[10] = {};
  ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));
  ASSERT_THAT(RetryEINTR(write)(sockets->second_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));

  // Wait until second sees the data on its side but don't read it.
  struct pollfd poll_fd = {sockets->second_fd(), POLLIN, 0};
  constexpr int kPollTimeoutMs = 30000;  // Wait up to 30 seconds for the data.
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  // Wait until first sees the data on its side but don't read it.
  struct pollfd poll_fd2 = {sockets->first_fd(), POLLIN, 0};
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd2, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  // Now close the connected socket without reading the data from the second.
  ASSERT_THAT(close(sockets->release_second_fd()), SyscallSucceeds());

  // Wait for the other end to receive the RST (up to 30 seconds).
  struct pollfd poll_fd3 = {sockets->first_fd(), POLLHUP, 0};
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd3, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  // Since we also have data buffered we should be able to read it before
  // the syscall will fail with ECONNRESET.
  ASSERT_THAT(RetryEINTR(read)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));

  // A shutdown with unread data will cause a RST to be sent instead
  // of a FIN, per RFC 2525 section 2.17; this is also what Linux does.
  ASSERT_THAT(RetryEINTR(read)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallFailsWithErrno(ECONNRESET));
}

// This test will verify that a clean shutdown (FIN) is preformed when there
// is unread data but only the write side is closed.
TEST_P(TCPSocketPairTest, FINSentOnShutdownWrWithUnreadData) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char buf[10] = {};
  ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));

  // Wait until t_ sees the data on its side but don't read it.
  struct pollfd poll_fd = {sockets->second_fd(), POLLIN | POLLHUP, 0};
  constexpr int kPollTimeoutMs = 20000;  // Wait up to 20 seconds for the data.
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  // Now shutdown the write end leaving the read end open.
  ASSERT_THAT(shutdown(sockets->second_fd(), SHUT_WR), SyscallSucceeds());

  // Wait for the other end to receive the FIN (up to 20 seconds).
  struct pollfd poll_fd2 = {sockets->first_fd(), POLLIN | POLLHUP, 0};
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd2, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  // Since we didn't shutdown the read end this will be a clean close.
  ASSERT_THAT(RetryEINTR(read)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(0));
}

// This test will verify that when data is received by a socket, even if it's
// not read SHUT_RD will not cause any packets to be generated.
TEST_P(TCPSocketPairTest, ShutdownRdShouldCauseNoPacketsWithUnreadData) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char buf[10] = {};
  ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));

  // Wait until t_ sees the data on its side but don't read it.
  struct pollfd poll_fd = {sockets->second_fd(), POLLIN | POLLHUP, 0};
  constexpr int kPollTimeoutMs = 20000;  // Wait up to 20 seconds for the data.
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  // Now shutdown the read end, this will generate no packets to the other end.
  ASSERT_THAT(shutdown(sockets->second_fd(), SHUT_RD), SyscallSucceeds());

  // We should not receive any events on the other side of the socket.
  struct pollfd poll_fd2 = {sockets->first_fd(), POLLIN | POLLHUP, 0};
  constexpr int kPollNoResponseTimeoutMs = 3000;
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd2, 1, kPollNoResponseTimeoutMs),
              SyscallSucceedsWithValue(0));  // Timeout.
}

// This test will verify that a socket which has unread data will still allow
// the data to be read after shutting down the read side, and once there is no
// unread data left, then read will return an EOF.
TEST_P(TCPSocketPairTest, ShutdownRdAllowsReadOfReceivedDataBeforeEOF) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char buf[10] = {};
  ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));

  // Wait until t_ sees the data on its side but don't read it.
  struct pollfd poll_fd = {sockets->second_fd(), POLLIN | POLLHUP, 0};
  constexpr int kPollTimeoutMs = 20000;  // Wait up to 20 seconds for the data.
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  // Now shutdown the read end.
  ASSERT_THAT(shutdown(sockets->second_fd(), SHUT_RD), SyscallSucceeds());

  // Even though we did a SHUT_RD on the read end we can still read the data.
  ASSERT_THAT(RetryEINTR(read)(sockets->second_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));

  // After reading all of the data, reading the closed read end returns EOF.
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));
  ASSERT_THAT(RetryEINTR(read)(sockets->second_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(0));
}

// This test verifies that a shutdown(wr) by the server after sending
// data allows the client to still read() the queued data and a client
// close after sending response allows server to read the incoming
// response.
TEST_P(TCPSocketPairTest, ShutdownWrServerClientClose) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  ScopedThread t([&]() {
    char sbuf[10] = {};
    ASSERT_THAT(RetryEINTR(read)(sockets->first_fd(), sbuf, sizeof(sbuf)),
                SyscallSucceedsWithValue(sizeof(sbuf)));
    ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), sbuf, sizeof(sbuf)),
                SyscallSucceedsWithValue(sizeof(sbuf)));
    ASSERT_THAT(close(sockets->release_first_fd()),
                SyscallSucceedsWithValue(0));
  });
  char buf[10] = {};
  ASSERT_THAT(RetryEINTR(write)(sockets->second_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));
  ASSERT_THAT(RetryEINTR(shutdown)(sockets->second_fd(), SHUT_WR),
              SyscallSucceedsWithValue(0));
  t.Join();

  ASSERT_THAT(RetryEINTR(read)(sockets->second_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));
}

TEST_P(TCPSocketPairTest, ClosedReadNonBlockingSocket) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  // Set the read end to O_NONBLOCK.
  int opts = 0;
  ASSERT_THAT(opts = fcntl(sockets->second_fd(), F_GETFL), SyscallSucceeds());
  ASSERT_THAT(fcntl(sockets->second_fd(), F_SETFL, opts | O_NONBLOCK),
              SyscallSucceeds());

  char buf[10] = {};
  ASSERT_THAT(RetryEINTR(send)(sockets->first_fd(), buf, sizeof(buf), 0),
              SyscallSucceedsWithValue(sizeof(buf)));

  // Wait until second_fd sees the data and then recv it.
  struct pollfd poll_fd = {sockets->second_fd(), POLLIN, 0};
  constexpr int kPollTimeoutMs = 2000;  // Wait up to 2 seconds for the data.
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  ASSERT_THAT(RetryEINTR(recv)(sockets->second_fd(), buf, sizeof(buf), 0),
              SyscallSucceedsWithValue(sizeof(buf)));

  // Now shutdown the write end leaving the read end open.
  ASSERT_THAT(close(sockets->release_first_fd()), SyscallSucceeds());

  // Wait for close notification and recv again.
  struct pollfd poll_fd2 = {sockets->second_fd(), POLLIN, 0};
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd2, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  ASSERT_THAT(RetryEINTR(recv)(sockets->second_fd(), buf, sizeof(buf), 0),
              SyscallSucceedsWithValue(0));
}

TEST_P(TCPSocketPairTest,
       ShutdownRdUnreadDataShouldCauseNoPacketsUnlessClosed) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char buf[10] = {};
  ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));

  // Wait until t_ sees the data on its side but don't read it.
  struct pollfd poll_fd = {sockets->second_fd(), POLLIN | POLLHUP, 0};
  constexpr int kPollTimeoutMs = 20000;  // Wait up to 20 seconds for the data.
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  // Now shutdown the read end, this will generate no packets to the other end.
  ASSERT_THAT(shutdown(sockets->second_fd(), SHUT_RD), SyscallSucceeds());

  // We should not receive any events on the other side of the socket.
  struct pollfd poll_fd2 = {sockets->first_fd(), POLLIN | POLLHUP, 0};
  constexpr int kPollNoResponseTimeoutMs = 3000;
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd2, 1, kPollNoResponseTimeoutMs),
              SyscallSucceedsWithValue(0));  // Timeout.

  // Now since we've fully closed the connection it will generate a RST.
  ASSERT_THAT(close(sockets->release_second_fd()), SyscallSucceeds());
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd2, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));  // The other end has closed.

  // A shutdown with unread data will cause a RST to be sent instead
  // of a FIN, per RFC 2525 section 2.17; this is also what Linux does.
  ASSERT_THAT(RetryEINTR(read)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallFailsWithErrno(ECONNRESET));
}

TEST_P(TCPSocketPairTest, TCPCorkDefault) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CORK, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kSockOptOff);
}

TEST_P(TCPSocketPairTest, SetTCPCork) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CORK,
                         &kSockOptOn, sizeof(kSockOptOn)),
              SyscallSucceeds());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CORK, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kSockOptOn);

  ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CORK,
                         &kSockOptOff, sizeof(kSockOptOff)),
              SyscallSucceeds());

  EXPECT_THAT(
      getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CORK, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kSockOptOff);
}

TEST_P(TCPSocketPairTest, TCPCork) {
  // Disable save on this test, this test checks if the data is not recv'd by
  // the receiver after enabling TCP_CORK when the size of the packet < MSS.
  // But the save/resume may take more than the cork timeout of 200ms causing
  // all the corked packets to be sent and makes the test flaky.
  const DisableSave ds;
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CORK,
                         &kSockOptOn, sizeof(kSockOptOn)),
              SyscallSucceeds());

  constexpr char kData[] = "abc";
  ASSERT_THAT(WriteFd(sockets->first_fd(), kData, sizeof(kData)),
              SyscallSucceedsWithValue(sizeof(kData)));

  ASSERT_NO_FATAL_FAILURE(RecvNoData(sockets->second_fd()));

  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CORK,
                         &kSockOptOff, sizeof(kSockOptOff)),
              SyscallSucceeds());

  // Create a receive buffer larger than kData.
  char buf[(sizeof(kData) + 1) * 2] = {};
  ASSERT_THAT(RetryEINTR(recv)(sockets->second_fd(), buf, sizeof(buf), 0),
              SyscallSucceedsWithValue(sizeof(kData)));
  EXPECT_EQ(absl::string_view(kData, sizeof(kData)),
            absl::string_view(buf, sizeof(kData)));
}

TEST_P(TCPSocketPairTest, TCPQuickAckDefault) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_QUICKACK, &get,
                         &get_len),
              SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kSockOptOn);
}

TEST_P(TCPSocketPairTest, SetTCPQuickAck) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_QUICKACK,
                         &kSockOptOff, sizeof(kSockOptOff)),
              SyscallSucceeds());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_QUICKACK, &get,
                         &get_len),
              SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kSockOptOff);

  ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_QUICKACK,
                         &kSockOptOn, sizeof(kSockOptOn)),
              SyscallSucceeds());

  EXPECT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_QUICKACK, &get,
                         &get_len),
              SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kSockOptOn);
}

TEST_P(TCPSocketPairTest, SoKeepaliveDefault) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), SOL_SOCKET, SO_KEEPALIVE, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kSockOptOff);
}

TEST_P(TCPSocketPairTest, SetSoKeepalive) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  ASSERT_THAT(setsockopt(sockets->first_fd(), SOL_SOCKET, SO_KEEPALIVE,
                         &kSockOptOn, sizeof(kSockOptOn)),
              SyscallSucceeds());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), SOL_SOCKET, SO_KEEPALIVE, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kSockOptOn);

  ASSERT_THAT(setsockopt(sockets->first_fd(), SOL_SOCKET, SO_KEEPALIVE,
                         &kSockOptOff, sizeof(kSockOptOff)),
              SyscallSucceeds());

  EXPECT_THAT(
      getsockopt(sockets->first_fd(), SOL_SOCKET, SO_KEEPALIVE, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kSockOptOff);
}

TEST_P(TCPSocketPairTest, SetSoKeepaliveClosed) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  // Force a RST to be sent using SO_LINGER.
  auto linger_opt = linger{.l_onoff = 1, .l_linger = 0};
  ASSERT_THAT(setsockopt(sockets->second_fd(), SOL_SOCKET, SO_LINGER,
                         &linger_opt, sizeof(linger_opt)),
              SyscallSucceeds());
  ASSERT_THAT(close(sockets->release_second_fd()), SyscallSucceeds());

  // Wait for the other end to receive the RST (up to 20 seconds).
  constexpr int kPollTimeoutMs = 20000;
  auto pfd = pollfd{
      .fd = sockets->first_fd(),
      .events = POLLIN | POLLHUP,
      .revents = 0,
  };
  ASSERT_THAT(RetryEINTR(poll)(&pfd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));
  ASSERT_EQ(pfd.revents & POLLHUP, POLLHUP);

  // Now that the connection is closed, we should still be able to set
  // SO_KEEPALIVE.
  ASSERT_THAT(setsockopt(sockets->first_fd(), SOL_SOCKET, SO_KEEPALIVE,
                         &kSockOptOn, sizeof(kSockOptOn)),
              SyscallSucceeds());
  int get = -1;
  socklen_t get_len = sizeof(get);
  ASSERT_THAT(
      getsockopt(sockets->first_fd(), SOL_SOCKET, SO_KEEPALIVE, &get, &get_len),
      SyscallSucceeds());
  ASSERT_EQ(get, kSockOptOn);
  ASSERT_EQ(get_len, sizeof(get));
}

TEST_P(TCPSocketPairTest, TCPKeepidleDefault) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPIDLE, &get,
                         &get_len),
              SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, 2 * 60 * 60);  // 2 hours.
}

TEST_P(TCPSocketPairTest, TCPKeepintvlDefault) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPINTVL, &get,
                         &get_len),
              SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, 75);  // 75 seconds.
}

TEST_P(TCPSocketPairTest, SetTCPKeepidleZero) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  constexpr int kZero = 0;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPIDLE, &kZero,
                         sizeof(kZero)),
              SyscallFailsWithErrno(EINVAL));
}

TEST_P(TCPSocketPairTest, SetTCPKeepintvlZero) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  constexpr int kZero = 0;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPINTVL,
                         &kZero, sizeof(kZero)),
              SyscallFailsWithErrno(EINVAL));
}

// Copied from include/net/tcp.h.
constexpr int MAX_TCP_KEEPIDLE = 32767;
constexpr int MAX_TCP_KEEPINTVL = 32767;
constexpr int MAX_TCP_KEEPCNT = 127;

TEST_P(TCPSocketPairTest, SetTCPKeepidleAboveMax) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  constexpr int kAboveMax = MAX_TCP_KEEPIDLE + 1;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPIDLE,
                         &kAboveMax, sizeof(kAboveMax)),
              SyscallFailsWithErrno(EINVAL));
}

TEST_P(TCPSocketPairTest, SetTCPKeepintvlAboveMax) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  constexpr int kAboveMax = MAX_TCP_KEEPINTVL + 1;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPINTVL,
                         &kAboveMax, sizeof(kAboveMax)),
              SyscallFailsWithErrno(EINVAL));
}

TEST_P(TCPSocketPairTest, SetTCPKeepidleToMax) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPIDLE,
                         &MAX_TCP_KEEPIDLE, sizeof(MAX_TCP_KEEPIDLE)),
              SyscallSucceedsWithValue(0));

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPIDLE, &get,
                         &get_len),
              SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, MAX_TCP_KEEPIDLE);
}

TEST_P(TCPSocketPairTest, SetTCPKeepintvlToMax) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPINTVL,
                         &MAX_TCP_KEEPINTVL, sizeof(MAX_TCP_KEEPINTVL)),
              SyscallSucceedsWithValue(0));

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPINTVL, &get,
                         &get_len),
              SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, MAX_TCP_KEEPINTVL);
}

TEST_P(TCPSocketPairTest, TCPKeepcountDefault) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPCNT, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, 9);  // 9 keepalive probes.
}

TEST_P(TCPSocketPairTest, SetTCPKeepcountZero) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  constexpr int kZero = 0;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPCNT, &kZero,
                         sizeof(kZero)),
              SyscallFailsWithErrno(EINVAL));
}

TEST_P(TCPSocketPairTest, SetTCPKeepcountAboveMax) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  constexpr int kAboveMax = MAX_TCP_KEEPCNT + 1;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPCNT,
                         &kAboveMax, sizeof(kAboveMax)),
              SyscallFailsWithErrno(EINVAL));
}

TEST_P(TCPSocketPairTest, SetTCPKeepcountToMax) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPCNT,
                         &MAX_TCP_KEEPCNT, sizeof(MAX_TCP_KEEPCNT)),
              SyscallSucceedsWithValue(0));

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPCNT, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, MAX_TCP_KEEPCNT);
}

TEST_P(TCPSocketPairTest, SetTCPKeepcountToOne) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int keepaliveCount = 1;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPCNT,
                         &keepaliveCount, sizeof(keepaliveCount)),
              SyscallSucceedsWithValue(0));

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPCNT, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, keepaliveCount);
}

TEST_P(TCPSocketPairTest, SetTCPKeepcountToNegative) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int keepaliveCount = -5;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_KEEPCNT,
                         &keepaliveCount, sizeof(keepaliveCount)),
              SyscallFailsWithErrno(EINVAL));
}

TEST_P(TCPSocketPairTest, SetOOBInline) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  EXPECT_THAT(setsockopt(sockets->first_fd(), SOL_SOCKET, SO_OOBINLINE,
                         &kSockOptOn, sizeof(kSockOptOn)),
              SyscallSucceeds());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), SOL_SOCKET, SO_OOBINLINE, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kSockOptOn);
}

TEST_P(TCPSocketPairTest, MsgTruncMsgPeek) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  char sent_data[512];
  RandomizeBuffer(sent_data, sizeof(sent_data));
  ASSERT_THAT(
      RetryEINTR(send)(sockets->first_fd(), sent_data, sizeof(sent_data), 0),
      SyscallSucceedsWithValue(sizeof(sent_data)));

  // Read half of the data with MSG_TRUNC | MSG_PEEK. This way there will still
  // be some data left to read in the next step even if the data gets consumed.
  char received_data1[sizeof(sent_data) / 2] = {};
  ASSERT_THAT(RetryEINTR(recv)(sockets->second_fd(), received_data1,
                               sizeof(received_data1), MSG_TRUNC | MSG_PEEK),
              SyscallSucceedsWithValue(sizeof(received_data1)));

  // Check that we didn't get anything.
  char zeros[sizeof(received_data1)] = {};
  EXPECT_EQ(0, memcmp(zeros, received_data1, sizeof(received_data1)));

  // Check that all of the data is still there.
  char received_data2[sizeof(sent_data)] = {};
  ASSERT_THAT(RetryEINTR(recv)(sockets->second_fd(), received_data2,
                               sizeof(received_data2), 0),
              SyscallSucceedsWithValue(sizeof(sent_data)));

  EXPECT_EQ(0, memcmp(received_data2, sent_data, sizeof(sent_data)));
}

TEST_P(TCPSocketPairTest, SetCongestionControlSucceedsForSupported) {
  // This is Linux's net/tcp.h TCP_CA_NAME_MAX.
  const int kTcpCaNameMax = 16;

  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  // Netstack only supports reno & cubic so we only test these two values here.
  {
    const char kSetCC[kTcpCaNameMax] = "reno";
    ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CONGESTION,
                           &kSetCC, strlen(kSetCC)),
                SyscallSucceedsWithValue(0));

    char got_cc[kTcpCaNameMax];
    memset(got_cc, '1', sizeof(got_cc));
    socklen_t optlen = sizeof(got_cc);
    ASSERT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CONGESTION,
                           &got_cc, &optlen),
                SyscallSucceedsWithValue(0));
    EXPECT_EQ(0, memcmp(got_cc, kSetCC, sizeof(kSetCC)));
  }
  {
    const char kSetCC[kTcpCaNameMax] = "cubic";
    ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CONGESTION,
                           &kSetCC, strlen(kSetCC)),
                SyscallSucceedsWithValue(0));

    char got_cc[kTcpCaNameMax];
    memset(got_cc, '1', sizeof(got_cc));
    socklen_t optlen = sizeof(got_cc);
    ASSERT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CONGESTION,
                           &got_cc, &optlen),
                SyscallSucceedsWithValue(0));
    EXPECT_EQ(0, memcmp(got_cc, kSetCC, sizeof(kSetCC)));
  }
}

TEST_P(TCPSocketPairTest, SetGetTCPCongestionShortReadBuffer) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  {
    // Verify that getsockopt/setsockopt work with buffers smaller than
    // kTcpCaNameMax.
    const char kSetCC[] = "cubic";
    ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CONGESTION,
                           &kSetCC, strlen(kSetCC)),
                SyscallSucceedsWithValue(0));

    char got_cc[sizeof(kSetCC)];
    socklen_t optlen = sizeof(got_cc);
    ASSERT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CONGESTION,
                           &got_cc, &optlen),
                SyscallSucceedsWithValue(0));
    EXPECT_EQ(0, memcmp(got_cc, kSetCC, sizeof(got_cc)));
  }
}

TEST_P(TCPSocketPairTest, SetGetTCPCongestionLargeReadBuffer) {
  // This is Linux's net/tcp.h TCP_CA_NAME_MAX.
  const int kTcpCaNameMax = 16;

  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  {
    // Verify that getsockopt works with buffers larger than
    // kTcpCaNameMax.
    const char kSetCC[] = "cubic";
    ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CONGESTION,
                           &kSetCC, strlen(kSetCC)),
                SyscallSucceedsWithValue(0));

    char got_cc[kTcpCaNameMax + 5];
    socklen_t optlen = sizeof(got_cc);
    ASSERT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CONGESTION,
                           &got_cc, &optlen),
                SyscallSucceedsWithValue(0));
    // Linux copies the minimum of kTcpCaNameMax or the length of the passed in
    // buffer and sets optlen to the number of bytes actually copied
    // irrespective of the actual length of the congestion control name.
    EXPECT_EQ(kTcpCaNameMax, optlen);
    EXPECT_EQ(0, memcmp(got_cc, kSetCC, sizeof(kSetCC)));
  }
}

TEST_P(TCPSocketPairTest, SetCongestionControlFailsForUnsupported) {
  // This is Linux's net/tcp.h TCP_CA_NAME_MAX.
  const int kTcpCaNameMax = 16;

  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  char old_cc[kTcpCaNameMax];
  socklen_t optlen = sizeof(old_cc);
  ASSERT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CONGESTION,
                         &old_cc, &optlen),
              SyscallSucceedsWithValue(0));

  const char kSetCC[] = "invalid_ca_cc";
  ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CONGESTION,
                         &kSetCC, strlen(kSetCC)),
              SyscallFailsWithErrno(ENOENT));

  char got_cc[kTcpCaNameMax];
  optlen = sizeof(got_cc);
  ASSERT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CONGESTION,
                         &got_cc, &optlen),
              SyscallSucceedsWithValue(0));
  EXPECT_EQ(0, memcmp(got_cc, old_cc, sizeof(old_cc)));
}

// Linux and Netstack both default to a 60s TCP_LINGER2 timeout.
constexpr int kDefaultTCPLingerTimeout = 60;
// On Linux, the maximum linger2 timeout was changed from 60sec to 120sec.
constexpr int kMaxTCPLingerTimeout = 120;
constexpr int kOldMaxTCPLingerTimeout = 60;

TEST_P(TCPSocketPairTest, TCPLingerTimeoutDefault) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_LINGER2, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kDefaultTCPLingerTimeout);
}

TEST_P(TCPSocketPairTest, SetTCPLingerTimeoutLessThanZero) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  constexpr int kNegative = -1234;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_LINGER2,
                         &kNegative, sizeof(kNegative)),
              SyscallSucceedsWithValue(0));
  int get = INT_MAX;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_LINGER2, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, -1);
}

TEST_P(TCPSocketPairTest, SetTCPLingerTimeoutZero) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  constexpr int kZero = 0;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_LINGER2, &kZero,
                         sizeof(kZero)),
              SyscallSucceedsWithValue(0));
  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_LINGER2, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_THAT(get,
              AnyOf(Eq(kMaxTCPLingerTimeout), Eq(kOldMaxTCPLingerTimeout)));
}

TEST_P(TCPSocketPairTest, SoLingerOptionWithReset) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  // Set and get SO_LINGER with zero timeout.
  struct linger sl;
  sl.l_onoff = 1;
  sl.l_linger = 0;
  ASSERT_THAT(
      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
      SyscallSucceeds());
  char buf[1000] = {};
  ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));

  ASSERT_THAT(close(sockets->release_first_fd()), SyscallSucceeds());

  write(sockets->second_fd(), buf, sizeof(buf));
  ASSERT_THAT(RetryEINTR(read)(sockets->second_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));
}

TEST_P(TCPSocketPairTest, SetTCPLingerTimeoutAboveMax) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  // Values above the net.ipv4.tcp_fin_timeout are capped to tcp_fin_timeout
  // on linux (defaults to 60 seconds on linux).
  constexpr int kAboveDefault = kMaxTCPLingerTimeout + 1;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_LINGER2,
                         &kAboveDefault, sizeof(kAboveDefault)),
              SyscallSucceedsWithValue(0));

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_LINGER2, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  if (IsRunningOnGvisor() && !IsRunningWithHostinet()) {
    EXPECT_EQ(get, kMaxTCPLingerTimeout);
  } else {
    EXPECT_THAT(get,
                AnyOf(Eq(kMaxTCPLingerTimeout), Eq(kOldMaxTCPLingerTimeout)));
  }
}

TEST_P(TCPSocketPairTest, SetTCPLingerTimeout) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  // Values above the net.ipv4.tcp_fin_timeout are capped to tcp_fin_timeout
  // on linux (defaults to 60 seconds on linux).
  constexpr int kTCPLingerTimeout = kDefaultTCPLingerTimeout - 1;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_LINGER2,
                         &kTCPLingerTimeout, sizeof(kTCPLingerTimeout)),
              SyscallSucceedsWithValue(0));

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(
      getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_LINGER2, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kTCPLingerTimeout);
}

TEST_P(TCPSocketPairTest, TestTCPCloseWithData) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  ScopedThread t([&]() {
    // Close one end to trigger sending of a FIN.
    ASSERT_THAT(shutdown(sockets->second_fd(), SHUT_WR), SyscallSucceeds());
    char buf[3];
    ASSERT_THAT(read(sockets->second_fd(), buf, 3),
                SyscallSucceedsWithValue(3));
    absl::SleepFor(absl::Milliseconds(50));
    ASSERT_THAT(close(sockets->release_second_fd()), SyscallSucceeds());
  });

  absl::SleepFor(absl::Milliseconds(50));
  // Send some data then close.
  constexpr char kStr[] = "abc";
  ASSERT_THAT(write(sockets->first_fd(), kStr, 3), SyscallSucceedsWithValue(3));
  t.Join();
  ASSERT_THAT(close(sockets->release_first_fd()), SyscallSucceeds());
}

TEST_P(TCPSocketPairTest, TCPUserTimeoutDefault) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int get = -1;
  socklen_t get_len = sizeof(get);
  ASSERT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_USER_TIMEOUT,
                         &get, &get_len),
              SyscallSucceeds());
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, 0);  // 0 ms (disabled).
}

TEST_P(TCPSocketPairTest, SetTCPUserTimeoutZero) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  constexpr int kZero = 0;
  ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_USER_TIMEOUT,
                         &kZero, sizeof(kZero)),
              SyscallSucceeds());

  int get = -1;
  socklen_t get_len = sizeof(get);
  ASSERT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_USER_TIMEOUT,
                         &get, &get_len),
              SyscallSucceeds());
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, 0);  // 0 ms (disabled).
}

TEST_P(TCPSocketPairTest, SetTCPUserTimeoutBelowZero) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  constexpr int kNeg = -10;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_USER_TIMEOUT,
                         &kNeg, sizeof(kNeg)),
              SyscallFailsWithErrno(EINVAL));

  int get = -1;
  socklen_t get_len = sizeof(get);
  ASSERT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_USER_TIMEOUT,
                         &get, &get_len),
              SyscallSucceeds());
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, 0);  // 0 ms (disabled).
}

TEST_P(TCPSocketPairTest, SetTCPUserTimeoutAboveZero) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  constexpr int kAbove = 10;
  ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_USER_TIMEOUT,
                         &kAbove, sizeof(kAbove)),
              SyscallSucceeds());

  int get = -1;
  socklen_t get_len = sizeof(get);
  ASSERT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_USER_TIMEOUT,
                         &get, &get_len),
              SyscallSucceeds());
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, kAbove);
}

#ifdef __linux__
TEST_P(TCPSocketPairTest, SpliceFromPipe) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int fds[2];
  ASSERT_THAT(pipe(fds), SyscallSucceeds());
  FileDescriptor rfd(fds[0]);
  FileDescriptor wfd(fds[1]);

  // Fill with some random data.
  std::vector<char> buf(kPageSize / 2);
  RandomizeBuffer(buf.data(), buf.size());
  ASSERT_THAT(write(wfd.get(), buf.data(), buf.size()),
              SyscallSucceedsWithValue(buf.size()));

  EXPECT_THAT(
      splice(rfd.get(), nullptr, sockets->first_fd(), nullptr, kPageSize, 0),
      SyscallSucceedsWithValue(buf.size()));

  std::vector<char> rbuf(buf.size());
  ASSERT_THAT(read(sockets->second_fd(), rbuf.data(), rbuf.size()),
              SyscallSucceedsWithValue(buf.size()));
  EXPECT_EQ(memcmp(rbuf.data(), buf.data(), buf.size()), 0);
}

TEST_P(TCPSocketPairTest, SpliceToPipe) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int fds[2];
  ASSERT_THAT(pipe(fds), SyscallSucceeds());
  FileDescriptor rfd(fds[0]);
  FileDescriptor wfd(fds[1]);

  // Fill with some random data.
  std::vector<char> buf(kPageSize / 2);
  RandomizeBuffer(buf.data(), buf.size());
  ASSERT_THAT(write(sockets->first_fd(), buf.data(), buf.size()),
              SyscallSucceedsWithValue(buf.size()));
  shutdown(sockets->first_fd(), SHUT_WR);
  EXPECT_THAT(
      splice(sockets->second_fd(), nullptr, wfd.get(), nullptr, kPageSize, 0),
      SyscallSucceedsWithValue(buf.size()));

  std::vector<char> rbuf(buf.size());
  ASSERT_THAT(read(rfd.get(), rbuf.data(), rbuf.size()),
              SyscallSucceedsWithValue(buf.size()));
  EXPECT_EQ(memcmp(rbuf.data(), buf.data(), buf.size()), 0);
}

// Regression test for #9932.
TEST_P(TCPSocketPairTest, LargeSpliceFromPipe) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  // Create a pipe, increase its size from the default 64K, and fill it with
  // data.
  int pipe_fds[2];
  ASSERT_THAT(pipe(pipe_fds), SyscallSucceeds());
  const FileDescriptor pipe_rfd(pipe_fds[0]);
  const FileDescriptor pipe_wfd(pipe_fds[1]);
  constexpr size_t kPipeSize = 1 << 20;
  ASSERT_THAT(fcntl(pipe_wfd.get(), F_SETPIPE_SZ, kPipeSize),
              SyscallSucceeds());
  std::vector<char> orig_data(kPipeSize);
  RandomizeBuffer(orig_data.data(), orig_data.size());
  ASSERT_THAT(WriteFd(pipe_wfd.get(), orig_data.data(), orig_data.size()),
              SyscallSucceedsWithValue(orig_data.size()));

  // Splice all data from the pipe to one end of the TCP socket pair in a
  // separate thread, while draining the other end from this thread.
  std::vector<char> read_data(orig_data.size());
  ScopedThread reader_thread([&] {
    size_t spliced_bytes = 0;
    ssize_t n;
    while (spliced_bytes < orig_data.size()) {
      ASSERT_THAT(
          n = RetryEINTR(splice)(pipe_rfd.get(), nullptr, sockets->first_fd(),
                                 nullptr, orig_data.size() - spliced_bytes, 0),
          SyscallSucceeds());
      spliced_bytes += n;
    }
  });
  size_t read_bytes = 0;
  while (read_bytes < read_data.size()) {
    ssize_t n;
    ASSERT_THAT(n = RetryEINTR(read)(sockets->second_fd(),
                                     read_data.data() + read_bytes,
                                     read_data.size() - read_bytes),
                SyscallSucceeds());
    read_bytes += n;
  }

  // Check that correct data was spliced and read.
  EXPECT_EQ(0, memcmp(orig_data.data(), read_data.data(), orig_data.size()));
}

#include <sys/sendfile.h>

#include <memory>

TEST_P(TCPSocketPairTest, SendfileFromRegularFileSucceeds) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  const TempPath in_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
  const FileDescriptor in_fd =
      ASSERT_NO_ERRNO_AND_VALUE(Open(in_file.path(), O_RDWR));
  // Fill with some random data.
  std::vector<char> buf(kPageSize / 2);
  RandomizeBuffer(buf.data(), buf.size());
  ASSERT_THAT(pwrite(in_fd.get(), buf.data(), buf.size(), 0),
              SyscallSucceedsWithValue(buf.size()));

  EXPECT_THAT(
      sendfile(sockets->first_fd(), in_fd.get(), nullptr, buf.size() + 1),
      SyscallSucceedsWithValue(buf.size()));
  std::vector<char> rbuf(buf.size() + 1);
  ASSERT_THAT(read(sockets->second_fd(), rbuf.data(), rbuf.size()),
              SyscallSucceedsWithValue(buf.size()));
  EXPECT_EQ(memcmp(rbuf.data(), buf.data(), buf.size()), 0);
}
#endif  // __linux__

TEST_P(TCPSocketPairTest, SetTCPWindowClampBelowMinRcvBufConnectedSocket) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  // Discover minimum receive buf by setting a really low value
  // for the receive buffer.
  constexpr int kZero = 0;
  EXPECT_THAT(setsockopt(sockets->first_fd(), SOL_SOCKET, SO_RCVBUF, &kZero,
                         sizeof(kZero)),
              SyscallSucceeds());

  // Now retrieve the minimum value for SO_RCVBUF as the set above should
  // have caused SO_RCVBUF for the socket to be set to the minimum.
  int get = -1;
  socklen_t get_len = sizeof(get);
  ASSERT_THAT(
      getsockopt(sockets->first_fd(), SOL_SOCKET, SO_RCVBUF, &get, &get_len),
      SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  int min_so_rcvbuf = get;

  {
    // Setting TCP_WINDOW_CLAMP to zero for a connected socket is not permitted.
    constexpr int kZero = 0;
    EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_WINDOW_CLAMP,
                           &kZero, sizeof(kZero)),
                SyscallFailsWithErrno(EINVAL));

    // Non-zero clamp values below MIN_SO_RCVBUF/2 should result in the clamp
    // being set to MIN_SO_RCVBUF/2.
    int below_half_min_so_rcvbuf = min_so_rcvbuf / 2 - 1;
    EXPECT_THAT(
        setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_WINDOW_CLAMP,
                   &below_half_min_so_rcvbuf, sizeof(below_half_min_so_rcvbuf)),
        SyscallSucceeds());

    int get = -1;
    socklen_t get_len = sizeof(get);

    ASSERT_THAT(getsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_WINDOW_CLAMP,
                           &get, &get_len),
                SyscallSucceedsWithValue(0));
    EXPECT_EQ(get_len, sizeof(get));
    EXPECT_EQ(min_so_rcvbuf / 2, get);
  }
}

TEST_P(TCPSocketPairTest, IpMulticastTtlDefault) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(getsockopt(sockets->first_fd(), IPPROTO_IP, IP_MULTICAST_TTL,
                         &get, &get_len),
              SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_GT(get, 0);
}

TEST_P(TCPSocketPairTest, IpMulticastLoopDefault) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  int get = -1;
  socklen_t get_len = sizeof(get);
  EXPECT_THAT(getsockopt(sockets->first_fd(), IPPROTO_IP, IP_MULTICAST_LOOP,
                         &get, &get_len),
              SyscallSucceedsWithValue(0));
  EXPECT_EQ(get_len, sizeof(get));
  EXPECT_EQ(get, 1);
}

TEST_P(TCPSocketPairTest, TCPResetDuringClose) {
  DisableSave ds;  // Too many syscalls.
  constexpr int kThreadCount = 100;
  std::unique_ptr<ScopedThread> instances[kThreadCount];
  for (int i = 0; i < kThreadCount; i++) {
    instances[i] = std::make_unique<ScopedThread>([&]() {
      auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

      ScopedThread t([&]() {
        // Close one end to trigger sending of a FIN.
        struct pollfd poll_fd = {sockets->second_fd(), POLLIN | POLLHUP, 0};
        // Wait up to 20 seconds for the data.
        constexpr int kPollTimeoutMs = 20000;
        ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
                    SyscallSucceedsWithValue(1));
        ASSERT_THAT(close(sockets->release_second_fd()), SyscallSucceeds());
      });

      // Send some data then close.
      constexpr char kStr[] = "abc";
      ASSERT_THAT(write(sockets->first_fd(), kStr, 3),
                  SyscallSucceedsWithValue(3));
      absl::SleepFor(absl::Milliseconds(10));
      ASSERT_THAT(close(sockets->release_first_fd()), SyscallSucceeds());
      t.Join();
    });
  }
  for (int i = 0; i < kThreadCount; i++) {
    instances[i]->Join();
  }
}

// Test setsockopt and getsockopt for a socket with SO_LINGER option.
TEST_P(TCPSocketPairTest, SetAndGetLingerOption) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  // Check getsockopt before SO_LINGER option is set.
  struct linger got_linger = {-1, -1};
  socklen_t got_len = sizeof(got_linger);

  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
                         &got_linger, &got_len),
              SyscallSucceeds());
  ASSERT_THAT(got_len, sizeof(got_linger));
  struct linger want_linger = {};
  EXPECT_EQ(0, memcmp(&want_linger, &got_linger, got_len));

  // Set and get SO_LINGER with negative values.
  struct linger sl;
  sl.l_onoff = 1;
  sl.l_linger = -3;
  ASSERT_THAT(
      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
      SyscallSucceeds());
  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
                         &got_linger, &got_len),
              SyscallSucceeds());
  ASSERT_EQ(got_len, sizeof(got_linger));
  EXPECT_EQ(sl.l_onoff, got_linger.l_onoff);
  // Linux returns a different value as it uses HZ to convert the seconds to
  // jiffies which overflows for negative values. We want to be compatible with
  // linux for getsockopt return value.
  if (IsRunningOnGvisor() && !IsRunningWithHostinet()) {
    EXPECT_EQ(sl.l_linger, got_linger.l_linger);
  }

  // Set and get SO_LINGER option with positive values.
  sl.l_onoff = 1;
  sl.l_linger = 5;
  ASSERT_THAT(
      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
      SyscallSucceeds());
  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
                         &got_linger, &got_len),
              SyscallSucceeds());
  ASSERT_EQ(got_len, sizeof(got_linger));
  EXPECT_EQ(0, memcmp(&sl, &got_linger, got_len));
}

// Test socket to disable SO_LINGER option.
TEST_P(TCPSocketPairTest, SetOffLingerOption) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  // Set the SO_LINGER option.
  struct linger sl;
  sl.l_onoff = 1;
  sl.l_linger = 5;
  ASSERT_THAT(
      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
      SyscallSucceeds());

  // Check getsockopt after SO_LINGER option is set.
  struct linger got_linger = {-1, -1};
  socklen_t got_len = sizeof(got_linger);
  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
                         &got_linger, &got_len),
              SyscallSucceeds());
  ASSERT_EQ(got_len, sizeof(got_linger));
  EXPECT_EQ(0, memcmp(&sl, &got_linger, got_len));

  sl.l_onoff = 0;
  sl.l_linger = 5;
  ASSERT_THAT(
      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
      SyscallSucceeds());

  // Check getsockopt after SO_LINGER option is set to zero.
  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
                         &got_linger, &got_len),
              SyscallSucceeds());
  ASSERT_EQ(got_len, sizeof(got_linger));
  EXPECT_EQ(0, memcmp(&sl, &got_linger, got_len));
}

// Test close on dup'd socket with SO_LINGER option set.
TEST_P(TCPSocketPairTest, CloseWithLingerOption) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  // Set the SO_LINGER option.
  struct linger sl;
  sl.l_onoff = 1;
  sl.l_linger = 5;
  ASSERT_THAT(
      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
      SyscallSucceeds());

  // Check getsockopt after SO_LINGER option is set.
  struct linger got_linger = {-1, -1};
  socklen_t got_len = sizeof(got_linger);
  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
                         &got_linger, &got_len),
              SyscallSucceeds());
  ASSERT_EQ(got_len, sizeof(got_linger));
  EXPECT_EQ(0, memcmp(&sl, &got_linger, got_len));

  FileDescriptor dupFd = FileDescriptor(dup(sockets->first_fd()));
  ASSERT_THAT(close(sockets->release_first_fd()), SyscallSucceeds());
  char buf[10] = {};
  // Write on dupFd should succeed as socket will not be closed until
  // all references are removed.
  ASSERT_THAT(RetryEINTR(write)(dupFd.get(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));
  ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallFailsWithErrno(EBADF));

  // Close the socket.
  dupFd.reset();
  // Write on dupFd should fail as all references for socket are removed.
  ASSERT_THAT(RetryEINTR(write)(dupFd.get(), buf, sizeof(buf)),
              SyscallFailsWithErrno(EBADF));
}

TEST_P(TCPSocketPairTest, ResetWithSoLingerZeroTimeoutOption) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());

  // Check getsockopt before SO_LINGER option is set.
  struct linger got_linger = {-1, -1};
  socklen_t got_len = sizeof(got_linger);

  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
                         &got_linger, &got_len),
              SyscallSucceeds());
  ASSERT_THAT(got_len, sizeof(got_linger));
  struct linger want_linger = {};
  EXPECT_EQ(0, memcmp(&want_linger, &got_linger, got_len));

  char buf[10] = {};
  ASSERT_THAT(RetryEINTR(write)(sockets->first_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));

  // Set and get SO_LINGER with zero timeout.
  struct linger sl;
  sl.l_onoff = 1;
  sl.l_linger = 0;
  ASSERT_THAT(
      setsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER, &sl, sizeof(sl)),
      SyscallSucceeds());
  ASSERT_THAT(getsockopt(sockets->first_fd(), SOL_SOCKET, SO_LINGER,
                         &got_linger, &got_len),
              SyscallSucceeds());
  ASSERT_EQ(got_len, sizeof(got_linger));
  EXPECT_EQ(sl.l_onoff, got_linger.l_onoff);
  EXPECT_EQ(sl.l_linger, got_linger.l_linger);

  // Wait until the socket sees the data on its side but don't read it.
  struct pollfd poll_fd = {sockets->second_fd(), POLLIN | POLLHUP, 0};
  constexpr int kPollTimeoutMs = 20000;  // Wait up to 20 seconds for the data.
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  ASSERT_THAT(close(sockets->release_first_fd()), SyscallSucceeds());

  // Attempt to write, but not possible because of connection reset.
  poll_fd = {sockets->second_fd(), POLLHUP, 0};
  ASSERT_THAT(RetryEINTR(poll)(&poll_fd, 1, kPollTimeoutMs),
              SyscallSucceedsWithValue(1));

  char buffer[10] = {};
  ASSERT_THAT(RetryEINTR(write)(sockets->second_fd(), buffer, sizeof(buffer)),
              SyscallFailsWithErrno(ECONNRESET));

  ASSERT_THAT(RetryEINTR(read)(sockets->second_fd(), buf, sizeof(buf)),
              SyscallSucceedsWithValue(sizeof(buf)));
}

TEST_P(TCPSocketPairTest, WaitTillMSSWithCorkOption) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CORK,
                         &kSockOptOn, sizeof(kSockOptOn)),
              SyscallSucceeds());

  constexpr int kTCPMaxSeg = 1024;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_MAXSEG,
                         &kTCPMaxSeg, sizeof(kTCPMaxSeg)),
              SyscallSucceedsWithValue(0));

  // Use the buffer size which is guaranteed to be >= MSS.
  char buffer[1024] = {};
  EXPECT_THAT(RetryEINTR(send)(sockets->first_fd(), buffer, sizeof(buffer), 0),
              SyscallSucceedsWithValue(sizeof(buffer)));

  char buf[1024] = {};
  EXPECT_THAT(RetryEINTR(recv)(sockets->second_fd(), buf, sizeof(buf), 0),
              SyscallSucceedsWithValue(sizeof(buf)));
}

TEST_P(TCPSocketPairTest, WaitTillTimeoutWithCorkOption) {
  auto sockets = ASSERT_NO_ERRNO_AND_VALUE(NewSocketPair());
  ASSERT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_CORK,
                         &kSockOptOn, sizeof(kSockOptOn)),
              SyscallSucceeds());

  constexpr int kTCPMaxSeg = 1024;
  EXPECT_THAT(setsockopt(sockets->first_fd(), IPPROTO_TCP, TCP_MAXSEG,
                         &kTCPMaxSeg, sizeof(kTCPMaxSeg)),
              SyscallSucceedsWithValue(0));

  // Use buffer size less than MSS.
  char buffer[512] = {};
  EXPECT_THAT(RetryEINTR(send)(sockets->first_fd(), buffer, sizeof(buffer), 0),
              SyscallSucceedsWithValue(sizeof(buffer)));

  char buf[512] = {};
  EXPECT_THAT(RetryEINTR(recv)(sockets->second_fd(), buf, sizeof(buf), 0),
              SyscallSucceedsWithValue(sizeof(buf)));
}

}  // namespace testing
}  // namespace gvisor