path: root/test/syscalls/linux/socket_ip_tcp_generic.cc

// Copyright 2018 Google LLC
//
// 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 <netinet/in.h>
#include <netinet/tcp.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>

#include "gtest/gtest.h"
#include "gtest/gtest.h"
#include "test/syscalls/linux/socket_test_util.h"
#include "test/util/test_util.h"

namespace gvisor {
namespace testing {

TEST_P(TCPSocketPairTest, TcpInfoSucceedes) {
  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, ShortTcpInfoSucceedes) {
  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, ZeroTcpInfoSucceedes) {
  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());
}

// 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(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_fd.revents & (POLLHUP | POLLIN), 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 and data will
// remain in the buffer and can be read later.
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.

  // 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)));
}

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, 0);
}

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) {
  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);
}

}  // namespace testing
}  // namespace gvisor