// Copyright 2023 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 <fcntl.h>
#include <net/ethernet.h>
#include <netinet/icmp6.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/ip_icmp.h>
#include <netinet/udp.h>
#include <netpacket/packet.h>

#ifdef __linux__
#include <linux/errqueue.h>
#include <linux/filter.h>
#endif  // __linux__
#include <netinet/in.h>
#include <poll.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>

#ifndef SIOCGSTAMP
#include <linux/sockios.h>
#endif

#include "gtest/gtest.h"
#include "test/util/capability_util.h"
#include "test/util/file_descriptor.h"
#include "test/util/posix_error.h"
#include "test/util/socket_util.h"
#include "test/util/test_util.h"

namespace gvisor {
namespace testing {

namespace {

// Tests for UDP that require raw socket access.
class UdpSocketRawTest : public ::testing::TestWithParam<int> {};

TEST_P(UdpSocketRawTest, ReceiveWithZeroSourcePort) {
  // UDP sockets can't bind to port 0, so send a UDP packet via a raw IP
  // socket instead. If those aren't available, skip the test.
  if (!ASSERT_NO_ERRNO_AND_VALUE(HaveRawIPSocketCapability())) {
    GTEST_SKIP();
  }

  FileDescriptor udp_socket =
      ASSERT_NO_ERRNO_AND_VALUE(Socket(GetParam(), SOCK_DGRAM, 0));
  sockaddr_storage bind_addr = InetLoopbackAddr(GetParam());
  ASSERT_THAT(bind(udp_socket.get(), AsSockAddr(&bind_addr), sizeof(bind_addr)),
              SyscallSucceeds());
  socklen_t bind_addr_len = sizeof(bind_addr);
  ASSERT_THAT(
      getsockname(udp_socket.get(), AsSockAddr(&bind_addr), &bind_addr_len),
      SyscallSucceeds());
  uint16_t udp_port =
      ASSERT_NO_ERRNO_AND_VALUE(AddrPort(GetParam(), bind_addr));

  constexpr absl::string_view kMessage = "hi";

  // Set up the UDP body.
  struct udphdr udphdr = {
      .source = 0,
      .dest = udp_port,
      .len = htons(sizeof(udphdr) + kMessage.size()),
      .check = 0,
  };

  if (GetParam() == AF_INET) {
    udphdr.check = UDPChecksum(
        iphdr{
            .saddr = htonl(INADDR_LOOPBACK),
            .daddr = htonl(INADDR_LOOPBACK),
        },
        udphdr, kMessage.data(), kMessage.size());
  } else {
    udphdr.check = UDPChecksum(
        ip6_hdr{
            .ip6_src = in6addr_loopback,
            .ip6_dst = in6addr_loopback,
        },
        udphdr, kMessage.data(), kMessage.size());
  }
  // Copy the header and the payload into our packet buffer.
  char send_buf[sizeof(udphdr) + kMessage.size()];
  memcpy(send_buf, &udphdr, sizeof(udphdr));
  memcpy(send_buf + sizeof(udphdr), kMessage.data(), kMessage.size());

  {
    // Send the packet out a raw socket.
    struct sockaddr_storage raw_socket_addr = InetLoopbackAddr(GetParam());
    FileDescriptor raw_socket =
        ASSERT_NO_ERRNO_AND_VALUE(Socket(GetParam(), SOCK_RAW, IPPROTO_UDP));
    ASSERT_THAT(sendto(raw_socket.get(), send_buf, sizeof(send_buf), 0,
                       reinterpret_cast<struct sockaddr*>(&raw_socket_addr),
                       sizeof(raw_socket_addr)),
                SyscallSucceedsWithValue(sizeof(send_buf)));
  }

  // Receive and validate the data.
  char received[kMessage.size() + 1];
  struct sockaddr_storage src;
  socklen_t addr2len = sizeof(src);
  EXPECT_THAT(recvfrom(udp_socket.get(), received, sizeof(received), 0,
                       AsSockAddr(&src), &addr2len),
              SyscallSucceedsWithValue(kMessage.size()));
  ASSERT_EQ(src.ss_family, GetParam());
  ASSERT_EQ(ASSERT_NO_ERRNO_AND_VALUE(AddrPort(GetParam(), src)), 0);
  ASSERT_EQ(absl::string_view(received, kMessage.size()), kMessage);
}

INSTANTIATE_TEST_SUITE_P(AllInetTests, UdpSocketRawTest,
                         ::testing::Values(AF_INET, AF_INET6));

}  // namespace
}  // namespace testing
}  // namespace gvisor