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

// Copyright 2019 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 <arpa/inet.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/ip_icmp.h>
#include <poll.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "test/syscalls/linux/ip_socket_test_util.h"
#include "test/syscalls/linux/unix_domain_socket_test_util.h"
#include "test/util/capability_util.h"
#include "test/util/file_descriptor.h"
#include "test/util/socket_util.h"
#include "test/util/test_util.h"

// Note: in order to run these tests, /proc/sys/net/ipv4/ping_group_range will
// need to be configured to let the superuser create ping sockets (see icmp(7)).

namespace gvisor {
namespace testing {

namespace {

#define TCPHDR_RST 0x4
#define TCPHDR_FLAGS_OFF 13

using ::testing::AnyOf;

// Fixture for tests parameterized by protocol.
class RawSocketTest : public ::testing::TestWithParam<std::tuple<int, int>> {
 protected:
  // Creates a socket to be used in tests.
  void SetUp() override;

  // Closes the socket created by SetUp().
  void TearDown() override;

  // Sends buf via s_.
  void SendBuf(const char* buf, int buf_len);

  // Reads from s_ into recv_buf.
  void ReceiveBuf(char* recv_buf, size_t recv_buf_len);

  void ReceiveBufFrom(int sock, char* recv_buf, size_t recv_buf_len);

  int Protocol() { return std::get<0>(GetParam()); }

  int Family() { return std::get<1>(GetParam()); }

  socklen_t AddrLen() {
    if (Family() == AF_INET) {
      return sizeof(sockaddr_in);
    }
    return sizeof(sockaddr_in6);
  }

  int HdrLen() {
    if (Family() == AF_INET) {
      return sizeof(struct iphdr);
    }
    // IPv6 raw sockets don't include the header.
    return 0;
  }

  uint16_t Port(struct sockaddr* s) {
    if (Family() == AF_INET) {
      return ntohs(reinterpret_cast<struct sockaddr_in*>(s)->sin_port);
    }
    return ntohs(reinterpret_cast<struct sockaddr_in6*>(s)->sin6_port);
  }

  void* Addr(struct sockaddr* s) {
    if (Family() == AF_INET) {
      return &(reinterpret_cast<struct sockaddr_in*>(s)->sin_addr);
    }
    return &(reinterpret_cast<struct sockaddr_in6*>(s)->sin6_addr);
  }

  // The socket used for both reading and writing.
  int s_;

  // The loopback address.
  struct sockaddr_storage addr_;
};

void RawSocketTest::SetUp() {
  if (!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability())) {
    ASSERT_THAT(socket(Family(), SOCK_RAW, Protocol()),
                SyscallFailsWithErrno(EPERM));
    GTEST_SKIP();
  }

  ASSERT_THAT(s_ = socket(Family(), SOCK_RAW, Protocol()), SyscallSucceeds());

  addr_ = {};

  // We don't set ports because raw sockets don't have a notion of ports.
  if (Family() == AF_INET) {
    struct sockaddr_in* sin = reinterpret_cast<struct sockaddr_in*>(&addr_);
    sin->sin_family = AF_INET;
    sin->sin_addr.s_addr = htonl(INADDR_LOOPBACK);
  } else {
    struct sockaddr_in6* sin6 = reinterpret_cast<struct sockaddr_in6*>(&addr_);
    sin6->sin6_family = AF_INET6;
    sin6->sin6_addr = in6addr_loopback;
  }
}

void RawSocketTest::TearDown() {
  // TearDown will be run even if we skip the test.
  if (ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability())) {
    EXPECT_THAT(close(s_), SyscallSucceeds());
  }
}

// We should be able to create multiple raw sockets for the same protocol.
// BasicRawSocket::Setup creates the first one, so we only have to create one
// more here.
TEST_P(RawSocketTest, MultipleCreation) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  int s2;
  ASSERT_THAT(s2 = socket(Family(), SOCK_RAW, Protocol()), SyscallSucceeds());

  ASSERT_THAT(close(s2), SyscallSucceeds());
}

// Test that shutting down an unconnected socket fails.
TEST_P(RawSocketTest, FailShutdownWithoutConnect) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(shutdown(s_, SHUT_WR), SyscallFailsWithErrno(ENOTCONN));
  ASSERT_THAT(shutdown(s_, SHUT_RD), SyscallFailsWithErrno(ENOTCONN));
}

// Shutdown is a no-op for raw sockets (and datagram sockets in general).
TEST_P(RawSocketTest, ShutdownWriteNoop) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(
      connect(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
      SyscallSucceeds());
  ASSERT_THAT(shutdown(s_, SHUT_WR), SyscallSucceeds());

  // Arbitrary.
  constexpr char kBuf[] = "noop";
  ASSERT_THAT(RetryEINTR(write)(s_, kBuf, sizeof(kBuf)),
              SyscallSucceedsWithValue(sizeof(kBuf)));
}

// Shutdown is a no-op for raw sockets (and datagram sockets in general).
TEST_P(RawSocketTest, ShutdownReadNoop) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(
      connect(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
      SyscallSucceeds());
  ASSERT_THAT(shutdown(s_, SHUT_RD), SyscallSucceeds());

  // Arbitrary.
  constexpr char kBuf[] = "gdg";
  ASSERT_NO_FATAL_FAILURE(SendBuf(kBuf, sizeof(kBuf)));

  std::vector<char> c(sizeof(kBuf) + HdrLen());
  ASSERT_THAT(read(s_, c.data(), c.size()), SyscallSucceedsWithValue(c.size()));
}

// Test that listen() fails.
TEST_P(RawSocketTest, FailListen) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(listen(s_, 1), SyscallFailsWithErrno(ENOTSUP));
}

// Test that accept() fails.
TEST_P(RawSocketTest, FailAccept) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  struct sockaddr saddr;
  socklen_t addrlen;
  ASSERT_THAT(accept(s_, &saddr, &addrlen), SyscallFailsWithErrno(ENOTSUP));
}

TEST_P(RawSocketTest, BindThenGetSockName) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  struct sockaddr* addr = reinterpret_cast<struct sockaddr*>(&addr_);
  ASSERT_THAT(bind(s_, addr, AddrLen()), SyscallSucceeds());
  struct sockaddr_storage saddr_storage;
  struct sockaddr* saddr = reinterpret_cast<struct sockaddr*>(&saddr_storage);
  socklen_t saddrlen = AddrLen();
  ASSERT_THAT(getsockname(s_, saddr, &saddrlen), SyscallSucceeds());
  ASSERT_EQ(saddrlen, AddrLen());

  // The port is expected to hold the protocol number.
  EXPECT_EQ(Port(saddr), Protocol());

  char addrbuf[INET6_ADDRSTRLEN], saddrbuf[INET6_ADDRSTRLEN];
  const char* addrstr =
      inet_ntop(addr->sa_family, Addr(addr), addrbuf, sizeof(addrbuf));
  ASSERT_NE(addrstr, nullptr);
  const char* saddrstr =
      inet_ntop(saddr->sa_family, Addr(saddr), saddrbuf, sizeof(saddrbuf));
  ASSERT_NE(saddrstr, nullptr);
  EXPECT_STREQ(saddrstr, addrstr);
}

TEST_P(RawSocketTest, ConnectThenGetSockName) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  struct sockaddr* addr = reinterpret_cast<struct sockaddr*>(&addr_);
  ASSERT_THAT(connect(s_, addr, AddrLen()), SyscallSucceeds());
  struct sockaddr_storage saddr_storage;
  struct sockaddr* saddr = reinterpret_cast<struct sockaddr*>(&saddr_storage);
  socklen_t saddrlen = AddrLen();
  ASSERT_THAT(getsockname(s_, saddr, &saddrlen), SyscallSucceeds());
  ASSERT_EQ(saddrlen, AddrLen());

  // The port is expected to hold the protocol number.
  EXPECT_EQ(Port(saddr), Protocol());

  char addrbuf[INET6_ADDRSTRLEN], saddrbuf[INET6_ADDRSTRLEN];
  const char* addrstr =
      inet_ntop(addr->sa_family, Addr(addr), addrbuf, sizeof(addrbuf));
  ASSERT_NE(addrstr, nullptr);
  const char* saddrstr =
      inet_ntop(saddr->sa_family, Addr(saddr), saddrbuf, sizeof(saddrbuf));
  ASSERT_NE(saddrstr, nullptr);
  EXPECT_STREQ(saddrstr, addrstr);
}

// Test that getpeername() returns nothing before connect().
TEST_P(RawSocketTest, FailGetPeerNameBeforeConnect) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  struct sockaddr saddr;
  socklen_t addrlen = sizeof(saddr);
  ASSERT_THAT(getpeername(s_, &saddr, &addrlen),
              SyscallFailsWithErrno(ENOTCONN));
}

// Test that getpeername() returns something after connect().
TEST_P(RawSocketTest, GetPeerName) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(
      connect(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
      SyscallSucceeds());
  struct sockaddr saddr;
  socklen_t addrlen = sizeof(saddr);
  ASSERT_THAT(getpeername(s_, &saddr, &addrlen),
              SyscallFailsWithErrno(ENOTCONN));
  ASSERT_GT(addrlen, 0);
}

// Test that the socket is writable immediately.
TEST_P(RawSocketTest, PollWritableImmediately) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  struct pollfd pfd = {};
  pfd.fd = s_;
  pfd.events = POLLOUT;
  ASSERT_THAT(RetryEINTR(poll)(&pfd, 1, 10000), SyscallSucceedsWithValue(1));
}

// Test that the socket isn't readable before receiving anything.
TEST_P(RawSocketTest, PollNotReadableInitially) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  // Try to receive data with MSG_DONTWAIT, which returns immediately if there's
  // nothing to be read.
  char buf[117];
  ASSERT_THAT(RetryEINTR(recv)(s_, buf, sizeof(buf), MSG_DONTWAIT),
              SyscallFailsWithErrno(EAGAIN));
}

// Test that the socket becomes readable once something is written to it.
TEST_P(RawSocketTest, PollTriggeredOnWrite) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  // Write something so that there's data to be read.
  // Arbitrary.
  constexpr char kBuf[] = "JP5";
  ASSERT_NO_FATAL_FAILURE(SendBuf(kBuf, sizeof(kBuf)));

  struct pollfd pfd = {};
  pfd.fd = s_;
  pfd.events = POLLIN;
  ASSERT_THAT(RetryEINTR(poll)(&pfd, 1, 10000), SyscallSucceedsWithValue(1));
}

// Test that we can connect() to a valid IP (loopback).
TEST_P(RawSocketTest, ConnectToLoopback) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(
      connect(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
      SyscallSucceeds());
}

// Test that calling send() without connect() fails.
TEST_P(RawSocketTest, SendWithoutConnectFails) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  // Arbitrary.
  constexpr char kBuf[] = "Endgame was good";
  ASSERT_THAT(send(s_, kBuf, sizeof(kBuf), 0),
              SyscallFailsWithErrno(EDESTADDRREQ));
}

// Wildcard Bind.
TEST_P(RawSocketTest, BindToWildcard) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));
  struct sockaddr_storage addr;
  addr = {};

  // We don't set ports because raw sockets don't have a notion of ports.
  if (Family() == AF_INET) {
    struct sockaddr_in* sin = reinterpret_cast<struct sockaddr_in*>(&addr);
    sin->sin_family = AF_INET;
    sin->sin_addr.s_addr = htonl(INADDR_ANY);
  } else {
    struct sockaddr_in6* sin6 = reinterpret_cast<struct sockaddr_in6*>(&addr);
    sin6->sin6_family = AF_INET6;
    sin6->sin6_addr = in6addr_any;
  }

  ASSERT_THAT(bind(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
              SyscallSucceeds());
}

// Bind to localhost.
TEST_P(RawSocketTest, BindToLocalhost) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(bind(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
              SyscallSucceeds());
}

// Bind to a different address.
TEST_P(RawSocketTest, BindToInvalid) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  struct sockaddr_storage bind_addr = addr_;
  if (Family() == AF_INET) {
    struct sockaddr_in* sin = reinterpret_cast<struct sockaddr_in*>(&bind_addr);
    sin->sin_addr = {1};  // 1.0.0.0 - An address that we can't bind to.
  } else {
    struct sockaddr_in6* sin6 =
        reinterpret_cast<struct sockaddr_in6*>(&bind_addr);
    memset(&sin6->sin6_addr.s6_addr, 0, sizeof(sin6->sin6_addr.s6_addr));
    sin6->sin6_addr.s6_addr[0] = 1;  // 1: - An address that we can't bind to.
  }
  ASSERT_THAT(
      bind(s_, reinterpret_cast<struct sockaddr*>(&bind_addr), AddrLen()),
      SyscallFailsWithErrno(EADDRNOTAVAIL));
}

// Send and receive an packet.
TEST_P(RawSocketTest, SendAndReceive) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  // Arbitrary.
  constexpr char kBuf[] = "TB12";
  ASSERT_NO_FATAL_FAILURE(SendBuf(kBuf, sizeof(kBuf)));

  // Receive the packet and make sure it's identical.
  std::vector<char> recv_buf(sizeof(kBuf) + HdrLen());
  ASSERT_NO_FATAL_FAILURE(ReceiveBuf(recv_buf.data(), recv_buf.size()));
  EXPECT_EQ(memcmp(recv_buf.data() + HdrLen(), kBuf, sizeof(kBuf)), 0);
}

// We should be able to create multiple raw sockets for the same protocol and
// receive the same packet on both.
TEST_P(RawSocketTest, MultipleSocketReceive) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  int s2;
  ASSERT_THAT(s2 = socket(Family(), SOCK_RAW, Protocol()), SyscallSucceeds());

  // Arbitrary.
  constexpr char kBuf[] = "TB10";
  ASSERT_NO_FATAL_FAILURE(SendBuf(kBuf, sizeof(kBuf)));

  // Receive it on socket 1.
  std::vector<char> recv_buf1(sizeof(kBuf) + HdrLen());
  ASSERT_NO_FATAL_FAILURE(ReceiveBuf(recv_buf1.data(), recv_buf1.size()));

  // Receive it on socket 2.
  std::vector<char> recv_buf2(sizeof(kBuf) + HdrLen());
  ASSERT_NO_FATAL_FAILURE(
      ReceiveBufFrom(s2, recv_buf2.data(), recv_buf2.size()));

  EXPECT_EQ(memcmp(recv_buf1.data() + HdrLen(), recv_buf2.data() + HdrLen(),
                   sizeof(kBuf)),
            0);

  ASSERT_THAT(close(s2), SyscallSucceeds());
}

// Test that connect sends packets to the right place.
TEST_P(RawSocketTest, SendAndReceiveViaConnect) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(
      connect(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
      SyscallSucceeds());

  // Arbitrary.
  constexpr char kBuf[] = "JH4";
  ASSERT_THAT(send(s_, kBuf, sizeof(kBuf), 0),
              SyscallSucceedsWithValue(sizeof(kBuf)));

  // Receive the packet and make sure it's identical.
  std::vector<char> recv_buf(sizeof(kBuf) + HdrLen());
  ASSERT_NO_FATAL_FAILURE(ReceiveBuf(recv_buf.data(), recv_buf.size()));
  EXPECT_EQ(memcmp(recv_buf.data() + HdrLen(), kBuf, sizeof(kBuf)), 0);
}

// Bind to localhost, then send and receive packets.
TEST_P(RawSocketTest, BindSendAndReceive) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(bind(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
              SyscallSucceeds());

  // Arbitrary.
  constexpr char kBuf[] = "DR16";
  ASSERT_NO_FATAL_FAILURE(SendBuf(kBuf, sizeof(kBuf)));

  // Receive the packet and make sure it's identical.
  std::vector<char> recv_buf(sizeof(kBuf) + HdrLen());
  ASSERT_NO_FATAL_FAILURE(ReceiveBuf(recv_buf.data(), recv_buf.size()));
  EXPECT_EQ(memcmp(recv_buf.data() + HdrLen(), kBuf, sizeof(kBuf)), 0);
}

// Bind and connect to localhost and send/receive packets.
TEST_P(RawSocketTest, BindConnectSendAndReceive) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(bind(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
              SyscallSucceeds());
  ASSERT_THAT(
      connect(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
      SyscallSucceeds());

  // Arbitrary.
  constexpr char kBuf[] = "DG88";
  ASSERT_NO_FATAL_FAILURE(SendBuf(kBuf, sizeof(kBuf)));

  // Receive the packet and make sure it's identical.
  std::vector<char> recv_buf(sizeof(kBuf) + HdrLen());
  ASSERT_NO_FATAL_FAILURE(ReceiveBuf(recv_buf.data(), recv_buf.size()));
  EXPECT_EQ(memcmp(recv_buf.data() + HdrLen(), kBuf, sizeof(kBuf)), 0);
}

// Check that setting SO_RCVBUF below min is clamped to the minimum
// receive buffer size.
TEST_P(RawSocketTest, SetSocketRecvBufBelowMin) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  // Discover minimum receive buf size by trying to set it to zero.
  // See:
  // https://github.com/torvalds/linux/blob/a5dc8300df75e8b8384b4c82225f1e4a0b4d9b55/net/core/sock.c#L820
  constexpr int kRcvBufSz = 0;
  ASSERT_THAT(
      setsockopt(s_, SOL_SOCKET, SO_RCVBUF, &kRcvBufSz, sizeof(kRcvBufSz)),
      SyscallSucceeds());

  int min = 0;
  socklen_t min_len = sizeof(min);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_RCVBUF, &min, &min_len),
              SyscallSucceeds());

  // Linux doubles the value so let's use a value that when doubled will still
  // be smaller than min.
  int below_min = min / 2 - 1;
  ASSERT_THAT(
      setsockopt(s_, SOL_SOCKET, SO_RCVBUF, &below_min, sizeof(below_min)),
      SyscallSucceeds());

  int val = 0;
  socklen_t val_len = sizeof(val);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_RCVBUF, &val, &val_len),
              SyscallSucceeds());

  ASSERT_EQ(min, val);
}

// Check that setting SO_RCVBUF above max is clamped to the maximum
// receive buffer size.
TEST_P(RawSocketTest, SetSocketRecvBufAboveMax) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  // Discover max buf size by trying to set the largest possible buffer size.
  constexpr int kRcvBufSz = 0xffffffff;
  ASSERT_THAT(
      setsockopt(s_, SOL_SOCKET, SO_RCVBUF, &kRcvBufSz, sizeof(kRcvBufSz)),
      SyscallSucceeds());

  int max = 0;
  socklen_t max_len = sizeof(max);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_RCVBUF, &max, &max_len),
              SyscallSucceeds());

  int above_max = max + 1;
  ASSERT_THAT(
      setsockopt(s_, SOL_SOCKET, SO_RCVBUF, &above_max, sizeof(above_max)),
      SyscallSucceeds());

  int val = 0;
  socklen_t val_len = sizeof(val);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_RCVBUF, &val, &val_len),
              SyscallSucceeds());
  ASSERT_EQ(max, val);
}

// Check that setting SO_RCVBUF min <= kRcvBufSz <= max is honored.
TEST_P(RawSocketTest, SetSocketRecvBuf) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  int max = 0;
  int min = 0;
  {
    // Discover max buf size by trying to set a really large buffer size.
    constexpr int kRcvBufSz = 0xffffffff;
    ASSERT_THAT(
        setsockopt(s_, SOL_SOCKET, SO_RCVBUF, &kRcvBufSz, sizeof(kRcvBufSz)),
        SyscallSucceeds());

    max = 0;
    socklen_t max_len = sizeof(max);
    ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_RCVBUF, &max, &max_len),
                SyscallSucceeds());
  }

  {
    // Discover minimum buffer size by trying to set a zero size receive buffer
    // size.
    // See:
    // https://github.com/torvalds/linux/blob/a5dc8300df75e8b8384b4c82225f1e4a0b4d9b55/net/core/sock.c#L820
    constexpr int kRcvBufSz = 0;
    ASSERT_THAT(
        setsockopt(s_, SOL_SOCKET, SO_RCVBUF, &kRcvBufSz, sizeof(kRcvBufSz)),
        SyscallSucceeds());

    socklen_t min_len = sizeof(min);
    ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_RCVBUF, &min, &min_len),
                SyscallSucceeds());
  }

  int quarter_sz = min + (max - min) / 4;
  ASSERT_THAT(
      setsockopt(s_, SOL_SOCKET, SO_RCVBUF, &quarter_sz, sizeof(quarter_sz)),
      SyscallSucceeds());

  int val = 0;
  socklen_t val_len = sizeof(val);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_RCVBUF, &val, &val_len),
              SyscallSucceeds());

  // Linux doubles the value set by SO_SNDBUF/SO_RCVBUF.
  quarter_sz *= 2;
  ASSERT_EQ(quarter_sz, val);
}

// Check that setting SO_SNDBUF below min is clamped to the minimum
// receive buffer size.
TEST_P(RawSocketTest, SetSocketSendBufBelowMin) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  // Discover minimum buffer size by trying to set it to zero.
  constexpr int kSndBufSz = 0;
  ASSERT_THAT(
      setsockopt(s_, SOL_SOCKET, SO_SNDBUF, &kSndBufSz, sizeof(kSndBufSz)),
      SyscallSucceeds());

  int min = 0;
  socklen_t min_len = sizeof(min);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_SNDBUF, &min, &min_len),
              SyscallSucceeds());

  // Linux doubles the value so let's use a value that when doubled will still
  // be smaller than min.
  int below_min = min / 2 - 1;
  ASSERT_THAT(
      setsockopt(s_, SOL_SOCKET, SO_SNDBUF, &below_min, sizeof(below_min)),
      SyscallSucceeds());

  int val = 0;
  socklen_t val_len = sizeof(val);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_SNDBUF, &val, &val_len),
              SyscallSucceeds());

  ASSERT_EQ(min, val);
}

// Check that setting SO_SNDBUF above max is clamped to the maximum
// send buffer size.
TEST_P(RawSocketTest, SetSocketSendBufAboveMax) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  // Discover maximum buffer size by trying to set it to a large value.
  constexpr int kSndBufSz = 0xffffffff;
  ASSERT_THAT(
      setsockopt(s_, SOL_SOCKET, SO_SNDBUF, &kSndBufSz, sizeof(kSndBufSz)),
      SyscallSucceeds());

  int max = 0;
  socklen_t max_len = sizeof(max);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_SNDBUF, &max, &max_len),
              SyscallSucceeds());

  int above_max = max + 1;
  ASSERT_THAT(
      setsockopt(s_, SOL_SOCKET, SO_SNDBUF, &above_max, sizeof(above_max)),
      SyscallSucceeds());

  int val = 0;
  socklen_t val_len = sizeof(val);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_SNDBUF, &val, &val_len),
              SyscallSucceeds());
  ASSERT_EQ(max, val);
}

// Check that setting SO_SNDBUF min <= kSndBufSz <= max is honored.
TEST_P(RawSocketTest, SetSocketSendBuf) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  int max = 0;
  int min = 0;
  {
    // Discover maximum buffer size by trying to set it to a large value.
    constexpr int kSndBufSz = 0xffffffff;
    ASSERT_THAT(
        setsockopt(s_, SOL_SOCKET, SO_SNDBUF, &kSndBufSz, sizeof(kSndBufSz)),
        SyscallSucceeds());

    max = 0;
    socklen_t max_len = sizeof(max);
    ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_SNDBUF, &max, &max_len),
                SyscallSucceeds());
  }

  {
    // Discover minimum buffer size by trying to set it to zero.
    constexpr int kSndBufSz = 0;
    ASSERT_THAT(
        setsockopt(s_, SOL_SOCKET, SO_SNDBUF, &kSndBufSz, sizeof(kSndBufSz)),
        SyscallSucceeds());

    socklen_t min_len = sizeof(min);
    ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_SNDBUF, &min, &min_len),
                SyscallSucceeds());
  }

  int quarter_sz = min + (max - min) / 4;
  ASSERT_THAT(
      setsockopt(s_, SOL_SOCKET, SO_SNDBUF, &quarter_sz, sizeof(quarter_sz)),
      SyscallSucceeds());

  int val = 0;
  socklen_t val_len = sizeof(val);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_SNDBUF, &val, &val_len),
              SyscallSucceeds());

  quarter_sz *= 2;
  ASSERT_EQ(quarter_sz, val);
}

void randomizePacket(char* buf, size_t len, int proto) {
  RandomizeBuffer(buf, len);
  // When testing with TCP sockets, ensure the RST flag is set. This is to
  // prevent the TCP stack from generating RSTs packets for unknown endpoints.
  if (proto == IPPROTO_TCP && len > TCPHDR_FLAGS_OFF)
    buf[TCPHDR_FLAGS_OFF] |= TCPHDR_RST;
}

// Test that receive buffer limits are not enforced when the recv buffer is
// empty.
TEST_P(RawSocketTest, RecvBufLimitsEmptyRecvBuffer) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(bind(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
              SyscallSucceeds());
  ASSERT_THAT(
      connect(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
      SyscallSucceeds());

  int min = 0;
  {
    // Discover minimum buffer size by trying to set it to zero.
    constexpr int kRcvBufSz = 0;
    ASSERT_THAT(
        setsockopt(s_, SOL_SOCKET, SO_RCVBUF, &kRcvBufSz, sizeof(kRcvBufSz)),
        SyscallSucceeds());

    socklen_t min_len = sizeof(min);
    ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_RCVBUF, &min, &min_len),
                SyscallSucceeds());
  }

  {
    // Send data of size min and verify that it's received.
    std::vector<char> buf(min);
    randomizePacket(buf.data(), buf.size(), Protocol());
    ASSERT_NO_FATAL_FAILURE(SendBuf(buf.data(), buf.size()));

    // Receive the packet and make sure it's identical.
    std::vector<char> recv_buf(buf.size() + HdrLen());
    ASSERT_NO_FATAL_FAILURE(ReceiveBuf(recv_buf.data(), recv_buf.size()));
    EXPECT_EQ(memcmp(recv_buf.data() + HdrLen(), buf.data(), buf.size()), 0);
  }

  {
    // Send data of size min + 1 and verify that its received. Both linux and
    // Netstack accept a dgram that exceeds rcvBuf limits if the receive buffer
    // is currently empty.
    std::vector<char> buf(min + 1);
    randomizePacket(buf.data(), buf.size(), Protocol());
    ASSERT_NO_FATAL_FAILURE(SendBuf(buf.data(), buf.size()));
    // Receive the packet and make sure it's identical.
    std::vector<char> recv_buf(buf.size() + HdrLen());
    ASSERT_NO_FATAL_FAILURE(ReceiveBuf(recv_buf.data(), recv_buf.size()));
    EXPECT_EQ(memcmp(recv_buf.data() + HdrLen(), buf.data(), buf.size()), 0);
  }
}

TEST_P(RawSocketTest, RecvBufLimits) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  ASSERT_THAT(bind(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
              SyscallSucceeds());
  ASSERT_THAT(
      connect(s_, reinterpret_cast<struct sockaddr*>(&addr_), AddrLen()),
      SyscallSucceeds());

  int min = 0;
  {
    // Discover minimum buffer size by trying to set it to zero.
    constexpr int kRcvBufSz = 0;
    ASSERT_THAT(
        setsockopt(s_, SOL_SOCKET, SO_RCVBUF, &kRcvBufSz, sizeof(kRcvBufSz)),
        SyscallSucceeds());

    socklen_t min_len = sizeof(min);
    ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_RCVBUF, &min, &min_len),
                SyscallSucceeds());
  }

  // Now set the limit to min * 2.
  int new_rcv_buf_sz = min * 2;
  ASSERT_THAT(setsockopt(s_, SOL_SOCKET, SO_RCVBUF, &new_rcv_buf_sz,
                         sizeof(new_rcv_buf_sz)),
              SyscallSucceeds());
  int rcv_buf_sz = 0;
  {
    socklen_t rcv_buf_len = sizeof(rcv_buf_sz);
    ASSERT_THAT(
        getsockopt(s_, SOL_SOCKET, SO_RCVBUF, &rcv_buf_sz, &rcv_buf_len),
        SyscallSucceeds());
  }

  // Set a receive timeout so that we don't block forever on reads if the test
  // fails.
  struct timeval tv {
    .tv_sec = 1, .tv_usec = 0,
  };
  ASSERT_THAT(setsockopt(s_, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv)),
              SyscallSucceeds());

  {
    std::vector<char> buf(min);
    randomizePacket(buf.data(), buf.size(), Protocol());

    ASSERT_NO_FATAL_FAILURE(SendBuf(buf.data(), buf.size()));
    ASSERT_NO_FATAL_FAILURE(SendBuf(buf.data(), buf.size()));
    ASSERT_NO_FATAL_FAILURE(SendBuf(buf.data(), buf.size()));
    ASSERT_NO_FATAL_FAILURE(SendBuf(buf.data(), buf.size()));
    int sent = 4;
    if (IsRunningOnGvisor() && !IsRunningWithHostinet()) {
      // Linux seems to drop the 4th packet even though technically it should
      // fit in the receive buffer.
      ASSERT_NO_FATAL_FAILURE(SendBuf(buf.data(), buf.size()));
      sent++;
    }

    // Verify that the expected number of packets are available to be read.
    for (int i = 0; i < sent - 1; i++) {
      // Receive the packet and make sure it's identical.
      std::vector<char> recv_buf(buf.size() + HdrLen());
      ASSERT_NO_FATAL_FAILURE(ReceiveBuf(recv_buf.data(), recv_buf.size()));
      EXPECT_EQ(memcmp(recv_buf.data() + HdrLen(), buf.data(), buf.size()), 0);
    }

    // Assert that the last packet is dropped because the receive buffer should
    // be full after the first four packets.
    std::vector<char> recv_buf(buf.size() + HdrLen());
    struct iovec iov = {};
    iov.iov_base = static_cast<void*>(const_cast<char*>(recv_buf.data()));
    iov.iov_len = buf.size();
    struct msghdr msg = {};
    msg.msg_iov = &iov;
    msg.msg_iovlen = 1;
    msg.msg_control = NULL;
    msg.msg_controllen = 0;
    msg.msg_flags = 0;
    ASSERT_THAT(RetryEINTR(recvmsg)(s_, &msg, MSG_DONTWAIT),
                SyscallFailsWithErrno(EAGAIN));
  }
}

void RawSocketTest::SendBuf(const char* buf, int buf_len) {
  // It's safe to use const_cast here because sendmsg won't modify the iovec or
  // address.
  struct iovec iov = {};
  iov.iov_base = static_cast<void*>(const_cast<char*>(buf));
  iov.iov_len = static_cast<size_t>(buf_len);
  struct msghdr msg = {};
  msg.msg_name = static_cast<void*>(&addr_);
  msg.msg_namelen = AddrLen();
  msg.msg_iov = &iov;
  msg.msg_iovlen = 1;
  msg.msg_control = NULL;
  msg.msg_controllen = 0;
  msg.msg_flags = 0;
  ASSERT_THAT(sendmsg(s_, &msg, 0), SyscallSucceedsWithValue(buf_len));
}

void RawSocketTest::ReceiveBuf(char* recv_buf, size_t recv_buf_len) {
  ASSERT_NO_FATAL_FAILURE(ReceiveBufFrom(s_, recv_buf, recv_buf_len));
}

void RawSocketTest::ReceiveBufFrom(int sock, char* recv_buf,
                                   size_t recv_buf_len) {
  ASSERT_NO_FATAL_FAILURE(RecvNoCmsg(sock, recv_buf, recv_buf_len));
}

TEST_P(RawSocketTest, SetSocketDetachFilterNoInstalledFilter) {
  // TODO(gvisor.dev/2746): Support SO_ATTACH_FILTER/SO_DETACH_FILTER.
  if (IsRunningOnGvisor()) {
    constexpr int val = 0;
    ASSERT_THAT(setsockopt(s_, SOL_SOCKET, SO_DETACH_FILTER, &val, sizeof(val)),
                SyscallSucceeds());
    return;
  }

  constexpr int val = 0;
  ASSERT_THAT(setsockopt(s_, SOL_SOCKET, SO_DETACH_FILTER, &val, sizeof(val)),
              SyscallFailsWithErrno(ENOENT));
}

TEST_P(RawSocketTest, GetSocketDetachFilter) {
  int val = 0;
  socklen_t val_len = sizeof(val);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_DETACH_FILTER, &val, &val_len),
              SyscallFailsWithErrno(ENOPROTOOPT));
}

TEST_P(RawSocketTest, BindToDevice) {
  constexpr char kLoopbackDeviceName[] = "lo";
  ASSERT_THAT(setsockopt(s_, SOL_SOCKET, SO_BINDTODEVICE, &kLoopbackDeviceName,
                         sizeof(kLoopbackDeviceName)),
              SyscallSucceeds());

  char got[IFNAMSIZ];
  socklen_t got_len = sizeof(got);
  ASSERT_THAT(getsockopt(s_, SOL_SOCKET, SO_BINDTODEVICE, &got, &got_len),
              SyscallSucceeds());
  ASSERT_EQ(got_len, sizeof(kLoopbackDeviceName));
  EXPECT_EQ(strcmp(kLoopbackDeviceName, got), 0);
}

// AF_INET6+SOCK_RAW+IPPROTO_RAW sockets can be created, but not written to.
TEST(RawSocketTest, IPv6ProtoRaw) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  int sock;
  ASSERT_THAT(sock = socket(AF_INET6, SOCK_RAW, IPPROTO_RAW),
              SyscallSucceeds());

  // Verify that writing yields EINVAL.
  char buf[] = "This is such a weird little edge case";
  struct sockaddr_in6 sin6 = {};
  sin6.sin6_family = AF_INET6;
  sin6.sin6_addr = in6addr_loopback;
  ASSERT_THAT(sendto(sock, buf, sizeof(buf), 0 /* flags */,
                     reinterpret_cast<struct sockaddr*>(&sin6), sizeof(sin6)),
              SyscallFailsWithErrno(EINVAL));
}

TEST(RawSocketTest, IPv6SendMsg) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  int sock;
  ASSERT_THAT(sock = socket(AF_INET6, SOCK_RAW, IPPROTO_TCP),
              SyscallSucceeds());

  char kBuf[] = "hello";
  struct iovec iov = {};
  iov.iov_base = static_cast<void*>(const_cast<char*>(kBuf));
  iov.iov_len = static_cast<size_t>(sizeof(kBuf));

  struct sockaddr_storage addr = {};
  struct sockaddr_in* sin = reinterpret_cast<struct sockaddr_in*>(&addr);
  sin->sin_family = AF_INET;
  sin->sin_addr.s_addr = htonl(INADDR_LOOPBACK);

  struct msghdr msg = {};
  msg.msg_name = static_cast<void*>(&addr);
  msg.msg_namelen = sizeof(sockaddr_in);
  msg.msg_iov = &iov;
  msg.msg_iovlen = 1;
  msg.msg_control = NULL;
  msg.msg_controllen = 0;
  msg.msg_flags = 0;
  ASSERT_THAT(sendmsg(sock, &msg, 0), SyscallFailsWithErrno(EINVAL));
}

TEST_P(RawSocketTest, ConnectOnIPv6Socket) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  int sock;
  ASSERT_THAT(sock = socket(AF_INET6, SOCK_RAW, IPPROTO_TCP),
              SyscallSucceeds());

  struct sockaddr_storage addr = {};
  struct sockaddr_in* sin = reinterpret_cast<struct sockaddr_in*>(&addr);
  sin->sin_family = AF_INET;
  sin->sin_addr.s_addr = htonl(INADDR_LOOPBACK);

  ASSERT_THAT(connect(sock, reinterpret_cast<struct sockaddr*>(&addr),
                      sizeof(sockaddr_in6)),
              SyscallFailsWithErrno(EAFNOSUPPORT));
}

INSTANTIATE_TEST_SUITE_P(
    AllInetTests, RawSocketTest,
    ::testing::Combine(::testing::Values(IPPROTO_TCP, IPPROTO_UDP),
                       ::testing::Values(AF_INET, AF_INET6)));

void TestRawSocketMaybeBindReceive(bool do_bind) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  constexpr char payload[] = "abcdefgh";

  const sockaddr_in addr = {
      .sin_family = AF_INET,
      .sin_addr = {.s_addr = htonl(INADDR_LOOPBACK)},
  };

  FileDescriptor udp_sock =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_DGRAM, 0));
  sockaddr_in udp_sock_bind_addr = addr;
  socklen_t udp_sock_bind_addr_len = sizeof(udp_sock_bind_addr);
  ASSERT_THAT(bind(udp_sock.get(),
                   reinterpret_cast<const sockaddr*>(&udp_sock_bind_addr),
                   sizeof(udp_sock_bind_addr)),
              SyscallSucceeds());
  ASSERT_THAT(getsockname(udp_sock.get(),
                          reinterpret_cast<sockaddr*>(&udp_sock_bind_addr),
                          &udp_sock_bind_addr_len),
              SyscallSucceeds());
  ASSERT_EQ(udp_sock_bind_addr_len, sizeof(udp_sock_bind_addr));

  FileDescriptor raw_sock =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_RAW, IPPROTO_UDP));

  auto test_recv = [&](const char* scope, uint32_t expected_destination) {
    SCOPED_TRACE(scope);

    constexpr int kInfinitePollTimeout = -1;
    pollfd pfd = {
        .fd = raw_sock.get(),
        .events = POLLIN,
    };
    ASSERT_THAT(RetryEINTR(poll)(&pfd, 1, kInfinitePollTimeout),
                SyscallSucceedsWithValue(1));

    struct ipv4_udp_packet {
      iphdr ip;
      udphdr udp;
      char data[sizeof(payload)];

      // Used to make sure only the required space is used.
      char unused_space;
    } ABSL_ATTRIBUTE_PACKED;
    constexpr size_t kExpectedIPPacketSize =
        offsetof(ipv4_udp_packet, unused_space);

    // Receive the whole IPv4 packet on the raw socket.
    ipv4_udp_packet read_raw_packet;
    sockaddr_in peer;
    socklen_t peerlen = sizeof(peer);
    ASSERT_EQ(
        recvfrom(raw_sock.get(), reinterpret_cast<char*>(&read_raw_packet),
                 sizeof(read_raw_packet), 0 /* flags */,
                 reinterpret_cast<sockaddr*>(&peer), &peerlen),
        static_cast<ssize_t>(kExpectedIPPacketSize))
        << strerror(errno);
    ASSERT_EQ(peerlen, sizeof(peer));
    EXPECT_EQ(read_raw_packet.ip.version, static_cast<unsigned int>(IPVERSION));
    // IHL holds the number of header bytes in 4 byte units.
    EXPECT_EQ(read_raw_packet.ip.ihl, sizeof(read_raw_packet.ip) / 4);
    EXPECT_EQ(ntohs(read_raw_packet.ip.tot_len), kExpectedIPPacketSize);
    EXPECT_EQ(ntohs(read_raw_packet.ip.frag_off) & IP_OFFMASK, 0);
    EXPECT_EQ(read_raw_packet.ip.protocol, SOL_UDP);
    EXPECT_EQ(ntohl(read_raw_packet.ip.saddr), INADDR_LOOPBACK);
    EXPECT_EQ(ntohl(read_raw_packet.ip.daddr), expected_destination);
    EXPECT_EQ(read_raw_packet.udp.source, udp_sock_bind_addr.sin_port);
    EXPECT_EQ(read_raw_packet.udp.dest, udp_sock_bind_addr.sin_port);
    EXPECT_EQ(ntohs(read_raw_packet.udp.len),
              kExpectedIPPacketSize - sizeof(read_raw_packet.ip));
    for (size_t i = 0; i < sizeof(payload); i++) {
      EXPECT_EQ(read_raw_packet.data[i], payload[i])
          << "byte mismatch @ idx=" << i;
    }
    EXPECT_EQ(peer.sin_family, AF_INET);
    EXPECT_EQ(peer.sin_port, 0);
    EXPECT_EQ(ntohl(peer.sin_addr.s_addr), INADDR_LOOPBACK);
  };

  if (do_bind) {
    ASSERT_THAT(bind(raw_sock.get(), reinterpret_cast<const sockaddr*>(&addr),
                     sizeof(addr)),
                SyscallSucceeds());
  }

  constexpr int kSendToFlags = 0;
  sockaddr_in different_addr = udp_sock_bind_addr;
  different_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK + 1);
  ASSERT_THAT(sendto(udp_sock.get(), payload, sizeof(payload), kSendToFlags,
                     reinterpret_cast<const sockaddr*>(&different_addr),
                     sizeof(different_addr)),
              SyscallSucceedsWithValue(sizeof(payload)));
  if (!do_bind) {
    ASSERT_NO_FATAL_FAILURE(
        test_recv("different_addr", ntohl(different_addr.sin_addr.s_addr)));
  }
  ASSERT_THAT(sendto(udp_sock.get(), payload, sizeof(payload), kSendToFlags,
                     reinterpret_cast<const sockaddr*>(&udp_sock_bind_addr),
                     sizeof(udp_sock_bind_addr)),
              SyscallSucceedsWithValue(sizeof(payload)));
  ASSERT_NO_FATAL_FAILURE(
      test_recv("addr", ntohl(udp_sock_bind_addr.sin_addr.s_addr)));
}

TEST(RawSocketTest, UnboundReceive) {
  // Test that a raw socket receives packets destined to any address if it is
  // not bound to an address.
  ASSERT_NO_FATAL_FAILURE(TestRawSocketMaybeBindReceive(false /* do_bind */));
}

TEST(RawSocketTest, BindReceive) {
  // Test that a raw socket only receives packets destined to the address it is
  // bound to.
  ASSERT_NO_FATAL_FAILURE(TestRawSocketMaybeBindReceive(true /* do_bind */));
}

TEST(RawSocketTest, ReceiveIPPacketInfo) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  FileDescriptor raw =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_RAW, IPPROTO_UDP));

  const sockaddr_in addr_ = {
      .sin_family = AF_INET,
      .sin_addr = {.s_addr = htonl(INADDR_LOOPBACK)},
  };
  ASSERT_THAT(
      bind(raw.get(), reinterpret_cast<const sockaddr*>(&addr_), sizeof(addr_)),
      SyscallSucceeds());

  // Register to receive IP packet info.
  ASSERT_THAT(setsockopt(raw.get(), IPPROTO_IP, IP_PKTINFO, &kSockOptOn,
                         sizeof(kSockOptOn)),
              SyscallSucceeds());

  constexpr char send_buf[] = "malformed UDP";
  ASSERT_THAT(sendto(raw.get(), send_buf, sizeof(send_buf), /*flags=*/0,
                     reinterpret_cast<const sockaddr*>(&addr_), sizeof(addr_)),
              SyscallSucceedsWithValue(sizeof(send_buf)));

  struct {
    iphdr ip;
    char data[sizeof(send_buf)];

    // Extra space in the receive buffer should be unused.
    char unused_space;
  } ABSL_ATTRIBUTE_PACKED recv_buf;

  size_t recv_buf_len = sizeof(recv_buf);
  in_pktinfo received_pktinfo;
  ASSERT_NO_FATAL_FAILURE(RecvPktInfo(raw.get(),
                                      reinterpret_cast<char*>(&recv_buf),
                                      &recv_buf_len, &received_pktinfo));

  EXPECT_EQ(recv_buf_len, sizeof(iphdr) + sizeof(send_buf));
  EXPECT_EQ(memcmp(send_buf, &recv_buf.data, sizeof(send_buf)), 0);
  EXPECT_EQ(recv_buf.ip.version, static_cast<unsigned int>(IPVERSION));
  // IHL holds the number of header bytes in 4 byte units.
  EXPECT_EQ(recv_buf.ip.ihl, sizeof(iphdr) / 4);
  EXPECT_EQ(ntohs(recv_buf.ip.tot_len), sizeof(iphdr) + sizeof(send_buf));
  EXPECT_EQ(recv_buf.ip.protocol, IPPROTO_UDP);
  EXPECT_EQ(ntohl(recv_buf.ip.saddr), INADDR_LOOPBACK);
  EXPECT_EQ(ntohl(recv_buf.ip.daddr), INADDR_LOOPBACK);

  EXPECT_EQ(received_pktinfo.ipi_ifindex,
            ASSERT_NO_ERRNO_AND_VALUE(GetLoopbackIndex()));
  EXPECT_EQ(ntohl(received_pktinfo.ipi_spec_dst.s_addr), INADDR_LOOPBACK);
  EXPECT_EQ(ntohl(received_pktinfo.ipi_addr.s_addr), INADDR_LOOPBACK);
}

TEST(RawSocketTest, ReceiveIPv6PacketInfo) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  FileDescriptor raw =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET6, SOCK_RAW, IPPROTO_UDP));

  const sockaddr_in6 addr_ = {
      .sin6_family = AF_INET6,
      .sin6_addr = in6addr_loopback,
  };
  ASSERT_THAT(
      bind(raw.get(), reinterpret_cast<const sockaddr*>(&addr_), sizeof(addr_)),
      SyscallSucceeds());

  // Register to receive IPv6 packet info.
  ASSERT_THAT(setsockopt(raw.get(), IPPROTO_IPV6, IPV6_RECVPKTINFO, &kSockOptOn,
                         sizeof(kSockOptOn)),
              SyscallSucceeds());

  constexpr char send_buf[] = "malformed UDP";
  ASSERT_THAT(sendto(raw.get(), send_buf, sizeof(send_buf), /*flags=*/0,
                     reinterpret_cast<const sockaddr*>(&addr_), sizeof(addr_)),
              SyscallSucceedsWithValue(sizeof(send_buf)));

  char recv_buf[sizeof(send_buf) + 1];
  size_t recv_buf_len = sizeof(recv_buf);
  in6_pktinfo received_pktinfo;
  ASSERT_NO_FATAL_FAILURE(RecvIPv6PktInfo(raw.get(),
                                          reinterpret_cast<char*>(&recv_buf),
                                          &recv_buf_len, &received_pktinfo));
  EXPECT_EQ(recv_buf_len, sizeof(send_buf));
  EXPECT_EQ(memcmp(send_buf, recv_buf, sizeof(send_buf)), 0);
  EXPECT_EQ(received_pktinfo.ipi6_ifindex,
            ASSERT_NO_ERRNO_AND_VALUE(GetLoopbackIndex()));
  ASSERT_EQ(memcmp(&received_pktinfo.ipi6_addr, &in6addr_loopback,
                   sizeof(in6addr_loopback)),
            0);
}

TEST(RawSocketTest, ReceiveTOS) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  FileDescriptor raw =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_RAW, IPPROTO_UDP));

  const sockaddr_in kAddr = {
      .sin_family = AF_INET,
      .sin_addr = {.s_addr = htonl(INADDR_LOOPBACK)},
  };
  ASSERT_THAT(
      bind(raw.get(), reinterpret_cast<const sockaddr*>(&kAddr), sizeof(kAddr)),
      SyscallSucceeds());

  constexpr int kArbitraryTOS = 42;
  ASSERT_THAT(setsockopt(raw.get(), IPPROTO_IP, IP_TOS, &kArbitraryTOS,
                         sizeof(kArbitraryTOS)),
              SyscallSucceeds());

  constexpr char kSendBuf[] = "malformed UDP";
  ASSERT_THAT(sendto(raw.get(), kSendBuf, sizeof(kSendBuf), 0 /* flags */,
                     reinterpret_cast<const sockaddr*>(&kAddr), sizeof(kAddr)),
              SyscallSucceedsWithValue(sizeof(kSendBuf)));

  // Register to receive TOS.
  constexpr int kOne = 1;
  ASSERT_THAT(
      setsockopt(raw.get(), IPPROTO_IP, IP_RECVTOS, &kOne, sizeof(kOne)),
      SyscallSucceeds());

  struct {
    iphdr ip;
    char data[sizeof(kSendBuf)];

    // Extra space in the receive buffer should be unused.
    char unused_space;
  } ABSL_ATTRIBUTE_PACKED recv_buf;
  uint8_t recv_tos;
  size_t recv_buf_len = sizeof(recv_buf);
  ASSERT_NO_FATAL_FAILURE(RecvTOS(raw.get(), reinterpret_cast<char*>(&recv_buf),
                                  &recv_buf_len, &recv_tos));
  ASSERT_EQ(recv_buf_len, sizeof(iphdr) + sizeof(kSendBuf));

  EXPECT_EQ(recv_buf.ip.version, static_cast<unsigned int>(IPVERSION));
  // IHL holds the number of header bytes in 4 byte units.
  EXPECT_EQ(recv_buf.ip.ihl, sizeof(iphdr) / 4);
  EXPECT_EQ(ntohs(recv_buf.ip.tot_len), sizeof(iphdr) + sizeof(kSendBuf));
  EXPECT_EQ(recv_buf.ip.protocol, IPPROTO_UDP);
  EXPECT_EQ(ntohl(recv_buf.ip.saddr), INADDR_LOOPBACK);
  EXPECT_EQ(ntohl(recv_buf.ip.daddr), INADDR_LOOPBACK);

  EXPECT_EQ(memcmp(kSendBuf, &recv_buf.data, sizeof(kSendBuf)), 0);

  if (const char* val = getenv("TOS_TCLASS_EXPECT_DEFAULT");
      val != nullptr && strcmp(val, "1") == 0) {
    // TODO(b/217448626): At least one Linux environment does not allow setting
    // a custom TOS. In this case, we additionally accept the default.
    EXPECT_THAT(recv_buf.ip.tos, AnyOf(kArbitraryTOS, 0u));
    EXPECT_THAT(recv_tos, AnyOf(kArbitraryTOS, 0u));
  } else {
    EXPECT_EQ(recv_buf.ip.tos, static_cast<uint8_t>(kArbitraryTOS));
    EXPECT_EQ(recv_tos, kArbitraryTOS);
  }
}

TEST(RawSocketTest, ReceiveTClass) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  FileDescriptor raw =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET6, SOCK_RAW, IPPROTO_UDP));

  const sockaddr_in6 kAddr = {
      .sin6_family = AF_INET6,
      .sin6_addr = in6addr_loopback,
  };
  ASSERT_THAT(
      bind(raw.get(), reinterpret_cast<const sockaddr*>(&kAddr), sizeof(kAddr)),
      SyscallSucceeds());

  constexpr int kArbitraryTClass = 42;
  ASSERT_THAT(setsockopt(raw.get(), IPPROTO_IPV6, IPV6_TCLASS,
                         &kArbitraryTClass, sizeof(kArbitraryTClass)),
              SyscallSucceeds());

  constexpr char send_buf[] = "malformed UDP";
  ASSERT_THAT(sendto(raw.get(), send_buf, sizeof(send_buf), 0 /* flags */,
                     reinterpret_cast<const sockaddr*>(&kAddr), sizeof(kAddr)),
              SyscallSucceedsWithValue(sizeof(send_buf)));

  // Register to receive TClass.
  constexpr int kOne = 1;
  ASSERT_THAT(
      setsockopt(raw.get(), IPPROTO_IPV6, IPV6_RECVTCLASS, &kOne, sizeof(kOne)),
      SyscallSucceeds());

  char recv_buf[sizeof(send_buf) + 1];
  size_t recv_buf_len = sizeof(recv_buf);
  int recv_tclass;
  ASSERT_NO_FATAL_FAILURE(
      RecvTClass(raw.get(), recv_buf, &recv_buf_len, &recv_tclass));
  ASSERT_EQ(recv_buf_len, sizeof(send_buf));

  EXPECT_EQ(memcmp(send_buf, recv_buf, sizeof(send_buf)), 0);

  if (const char* val = getenv("TOS_TCLASS_EXPECT_DEFAULT");
      val != nullptr && strcmp(val, "1") == 0) {
    // TODO(b/217448626): At least one Linux environment does not allow setting
    // a custom TCLASS. In this case, we additionally accept the default.
    EXPECT_THAT(recv_tclass, AnyOf(kArbitraryTClass, 0));
  } else {
    EXPECT_EQ(recv_tclass, kArbitraryTClass);
  }
}

TEST(RawSocketTest, ReceiveTTL) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  FileDescriptor raw =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET, SOCK_RAW, IPPROTO_UDP));

  const sockaddr_in kAddr = {
      .sin_family = AF_INET,
      .sin_addr = {.s_addr = htonl(INADDR_LOOPBACK)},
  };
  ASSERT_THAT(
      bind(raw.get(), reinterpret_cast<const sockaddr*>(&kAddr), sizeof(kAddr)),
      SyscallSucceeds());
  ASSERT_THAT(connect(raw.get(), reinterpret_cast<const sockaddr*>(&kAddr),
                      sizeof(kAddr)),
              SyscallSucceeds());

  constexpr int kArbitraryTTL = 42;
  ASSERT_THAT(setsockopt(raw.get(), IPPROTO_IP, IP_TTL, &kArbitraryTTL,
                         sizeof(kArbitraryTTL)),
              SyscallSucceeds());

  char send_buf[] = "malformed UDP";
  auto test_recv_ttl = [&](int expected_ttl) {
    // Register to receive TTL.
    constexpr int kOne = 1;
    ASSERT_THAT(
        setsockopt(raw.get(), IPPROTO_IP, IP_RECVTTL, &kOne, sizeof(kOne)),
        SyscallSucceeds());

    struct {
      iphdr ip;
      char data[sizeof(send_buf)];
    } ABSL_ATTRIBUTE_PACKED recv_buf;

    int recv_ttl;
    size_t recv_buf_len = sizeof(recv_buf);
    ASSERT_NO_FATAL_FAILURE(RecvTTL(raw.get(),
                                    reinterpret_cast<char*>(&recv_buf),
                                    &recv_buf_len, &recv_ttl));
    ASSERT_EQ(recv_buf_len, sizeof(iphdr) + sizeof(send_buf));

    EXPECT_EQ(recv_buf.ip.version, static_cast<unsigned int>(IPVERSION));
    // IHL holds the number of header bytes in 4 byte units.
    EXPECT_EQ(recv_buf.ip.ihl, sizeof(iphdr) / 4);
    EXPECT_EQ(ntohs(recv_buf.ip.tot_len), sizeof(iphdr) + sizeof(send_buf));
    EXPECT_EQ(recv_buf.ip.protocol, IPPROTO_UDP);
    EXPECT_EQ(ntohl(recv_buf.ip.saddr), INADDR_LOOPBACK);
    EXPECT_EQ(ntohl(recv_buf.ip.daddr), INADDR_LOOPBACK);
    EXPECT_EQ(recv_buf.ip.ttl, static_cast<uint8_t>(expected_ttl));

    EXPECT_EQ(memcmp(send_buf, &recv_buf.data, sizeof(send_buf)), 0);

    EXPECT_EQ(recv_ttl, expected_ttl);
  };

  ASSERT_THAT(send(raw.get(), send_buf, sizeof(send_buf), /*flags=*/0),
              SyscallSucceedsWithValue(sizeof(send_buf)));
  {
    SCOPED_TRACE("receive ttl set by option");
    ASSERT_NO_FATAL_FAILURE(test_recv_ttl(kArbitraryTTL));
  }

  constexpr int kArbitrarySendmsgTTL = kArbitraryTTL + 1;
  ASSERT_NO_FATAL_FAILURE(SendTTL(raw.get(), send_buf, size_t(sizeof(send_buf)),
                                  kArbitrarySendmsgTTL));
  {
    SCOPED_TRACE("receive ttl set by cmsg");
    ASSERT_NO_FATAL_FAILURE(test_recv_ttl(kArbitrarySendmsgTTL));
  }
}

TEST(RawSocketTest, ReceiveHopLimit) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  FileDescriptor raw =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET6, SOCK_RAW, IPPROTO_UDP));

  const sockaddr_in6 kAddr = {
      .sin6_family = AF_INET6,
      .sin6_addr = in6addr_loopback,
  };
  ASSERT_THAT(
      bind(raw.get(), reinterpret_cast<const sockaddr*>(&kAddr), sizeof(kAddr)),
      SyscallSucceeds());
  ASSERT_THAT(connect(raw.get(), reinterpret_cast<const sockaddr*>(&kAddr),
                      sizeof(kAddr)),
              SyscallSucceeds());

  constexpr int kArbitraryHopLimit = 42;
  ASSERT_THAT(setsockopt(raw.get(), IPPROTO_IPV6, IPV6_UNICAST_HOPS,
                         &kArbitraryHopLimit, sizeof(kArbitraryHopLimit)),
              SyscallSucceeds());

  // Register to receive HOPLIMIT.
  constexpr int kOne = 1;
  ASSERT_THAT(setsockopt(raw.get(), IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &kOne,
                         sizeof(kOne)),
              SyscallSucceeds());

  char send_buf[] = "malformed UDP";
  auto test_recv_hoplimit = [&](int expected_hoplimit) {
    char recv_buf[sizeof(send_buf)];
    size_t recv_buf_len = sizeof(recv_buf);
    int recv_hoplimit;
    ASSERT_NO_FATAL_FAILURE(
        RecvHopLimit(raw.get(), recv_buf, &recv_buf_len, &recv_hoplimit));
    ASSERT_EQ(recv_buf_len, sizeof(send_buf));

    EXPECT_EQ(memcmp(send_buf, recv_buf, sizeof(send_buf)), 0);
    EXPECT_EQ(recv_hoplimit, expected_hoplimit);
  };

  ASSERT_THAT(send(raw.get(), send_buf, sizeof(send_buf), /*flags=*/0),
              SyscallSucceedsWithValue(sizeof(send_buf)));
  {
    SCOPED_TRACE("receive hoplimit set by option");
    ASSERT_NO_FATAL_FAILURE(test_recv_hoplimit(kArbitraryHopLimit));
  }

  constexpr int kArbitrarySendmsgHopLimit = kArbitraryHopLimit + 1;
  ASSERT_NO_FATAL_FAILURE(SendHopLimit(raw.get(), send_buf,
                                       size_t(sizeof(send_buf)),
                                       kArbitrarySendmsgHopLimit));
  {
    SCOPED_TRACE("receive hoplimit set by cmsg");
    ASSERT_NO_FATAL_FAILURE(test_recv_hoplimit(kArbitrarySendmsgHopLimit));
  }
}

TEST(RawSocketTest, SetIPv6ChecksumError_MultipleOf2) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  FileDescriptor fd =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET6, SOCK_RAW, IPPROTO_UDP));

  int intV = 3;
  ASSERT_THAT(
      setsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, &intV, sizeof(intV)),
      SyscallFailsWithErrno(EINVAL));

  intV = 5;
  ASSERT_THAT(
      setsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, &intV, sizeof(intV)),
      SyscallFailsWithErrno(EINVAL));

  intV = 2;
  ASSERT_THAT(
      setsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, &intV, sizeof(intV)),
      SyscallSucceeds());

  intV = 4;
  ASSERT_THAT(
      setsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, &intV, sizeof(intV)),
      SyscallSucceeds());
}

TEST(RawSocketTest, SetIPv6ChecksumError_ReadShort) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  FileDescriptor fd =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET6, SOCK_RAW, IPPROTO_UDP));

  int intV = 2;
  if (IsRunningOnGvisor()) {
    // TODO(https://gvisor.dev/issue/6982): This is a deviation from Linux. We
    // should determine if we want to match the behaviour or handle the error
    // more gracefully.
    ASSERT_THAT(
        setsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, &intV, sizeof(intV) - 1),
        SyscallFailsWithErrno(EINVAL));
    return;
  }

  intV = std::numeric_limits<int>::max();
  if (intV % 2) {
    intV--;
  }

  if (const char* val = getenv("IPV6_CHECKSUM_SETSOCKOPT_SHORT_EXCEPTION");
      val != nullptr && strcmp(val, "1") == 0) {
    // TODO(https://issuetracker.google.com/issues/212585236): As of writing, it
    // seems like at least one Linux environment considers optlen unlike a local
    // Linux environment. In this case we call setsockopt with the full int so
    // that the rest of the test passes. Once the root cause for this difference
    // is found, we can update this check.
    ASSERT_THAT(
        setsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, &intV, sizeof(intV)),
        SyscallSucceeds());
  } else {
    ASSERT_THAT(
        setsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, &intV, sizeof(intV) - 1),
        SyscallSucceeds());
  }

  {
    int got;
    socklen_t got_len = sizeof(got);
    ASSERT_THAT(getsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, &got, &got_len),
                SyscallSucceeds());
    ASSERT_EQ(got_len, sizeof(got));
    // Even though we called setsockopt with a length smaller than an int, Linux
    // seems to read the full int.
    EXPECT_EQ(got, intV);
  }

  // If we have pass a pointer that points to memory less than the size of an
  // int, we get a bad address error.
  std::unique_ptr<uint8_t> u8V;
  // Linux seems to assume a full int but doesn't check the passed length.
  //
  // https://github.com/torvalds/linux/blob/a52a8e9eaf4a12dd58953fc622bb2bc08fd1d32c/net/ipv6/raw.c#L1023
  // shows that Linux copies optVal to an int without first checking optLen.
  ASSERT_THAT(
      setsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, u8V.get(), sizeof(*u8V)),
      SyscallFailsWithErrno(EFAULT));
}

TEST(RawSocketTest, IPv6Checksum_ValidateAndCalculate) {
  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability()));

  FileDescriptor checksum_set =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET6, SOCK_RAW, IPPROTO_UDP));

  FileDescriptor checksum_not_set =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET6, SOCK_RAW, IPPROTO_UDP));

  const sockaddr_in6 addr = {
      .sin6_family = AF_INET6,
      .sin6_addr = IN6ADDR_LOOPBACK_INIT,
  };

  auto bind_and_set_checksum = [&](const FileDescriptor& fd, int v) {
    ASSERT_THAT(
        bind(fd.get(), reinterpret_cast<const sockaddr*>(&addr), sizeof(addr)),
        SyscallSucceeds());

    int got;
    socklen_t got_len = sizeof(got);
    ASSERT_THAT(getsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, &got, &got_len),
                SyscallSucceeds());
    ASSERT_EQ(got_len, sizeof(got));
    EXPECT_EQ(got, -1);

    ASSERT_THAT(setsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, &v, sizeof(v)),
                SyscallSucceeds());
    ASSERT_THAT(getsockopt(fd.get(), SOL_IPV6, IPV6_CHECKSUM, &got, &got_len),
                SyscallSucceeds());
    ASSERT_EQ(got_len, sizeof(got));
    EXPECT_EQ(got, v);
  };

  struct udp_packet {
    udphdr udp;
    uint32_t value;
  } ABSL_ATTRIBUTE_PACKED;

  ASSERT_NO_FATAL_FAILURE(bind_and_set_checksum(
      checksum_set, offsetof(udp_packet, udp) + offsetof(udphdr, uh_sum)));
  ASSERT_NO_FATAL_FAILURE(bind_and_set_checksum(checksum_not_set, -1));

  auto send = [&](const FileDescriptor& fd, uint32_t v) {
    const udp_packet packet = {
        .value = v,
    };

    ASSERT_THAT(sendto(fd.get(), &packet, sizeof(packet), /*flags=*/0,
                       reinterpret_cast<const sockaddr*>(&addr), sizeof(addr)),
                SyscallSucceedsWithValue(sizeof(packet)));
  };

  auto expect_receive = [&](const FileDescriptor& fd, uint32_t v,
                            bool should_check_xsum) {
    udp_packet packet;
    sockaddr_in6 sender;
    socklen_t sender_len = sizeof(sender);
    ASSERT_THAT(
        RetryEINTR(recvfrom)(fd.get(), &packet, sizeof(packet), /*flags=*/0,
                             reinterpret_cast<sockaddr*>(&sender), &sender_len),
        SyscallSucceedsWithValue(sizeof(packet)));
    ASSERT_EQ(sender_len, sizeof(sender));
    EXPECT_EQ(memcmp(&sender, &addr, sizeof(addr)), 0);
    EXPECT_EQ(packet.value, v);
    if (should_check_xsum) {
      EXPECT_NE(packet.udp.uh_sum, 0);
    } else {
      EXPECT_EQ(packet.udp.uh_sum, 0);
    }
  };

  uint32_t counter = 1;
  // Packets sent through checksum_not_set will not have a valid checksum set so
  // checksum_set should not accept those packets.
  ASSERT_NO_FATAL_FAILURE(send(checksum_not_set, counter));
  ASSERT_NO_FATAL_FAILURE(expect_receive(checksum_not_set, counter, false));

  // Packets sent through checksum_set will have a valid checksum so both
  // sockets should accept them.
  ASSERT_NO_FATAL_FAILURE(send(checksum_set, ++counter));
  ASSERT_NO_FATAL_FAILURE(expect_receive(checksum_set, counter, true));
  ASSERT_NO_FATAL_FAILURE(expect_receive(checksum_not_set, counter, true));
}

}  // namespace

}  // namespace testing
}  // namespace gvisor