text: // Copyright (c) 2019 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include "gquiche/quic/core/quic_linux_socket_utils.h"
  
  #include <netinet/in.h>
  #include <stdint.h>
  #include <cstddef>
  #include <sstream>
  #include <vector>
  
  #include <string>
  
  #include "gquiche/quic/core/quic_circular_deque.h"
  #include "gquiche/quic/platform/api/quic_test.h"
  #include "gquiche/quic/test_tools/quic_mock_syscall_wrapper.h"
  
  using testing::_;
  using testing::InSequence;
  using testing::Invoke;
  
  namespace quic {
  namespace test {
  namespace {
  
  class QuicLinuxSocketUtilsTest : public QuicTest {
   protected:
    WriteResult TestWriteMultiplePackets(
        int fd,
        const QuicCircularDeque<BufferedWrite>::const_iterator& first,
        const QuicCircularDeque<BufferedWrite>::const_iterator& last,
        int* num_packets_sent) {
      QuicMMsgHdr mhdr(
          first, last, kCmsgSpaceForIp,
          [](QuicMMsgHdr* mhdr, int i, const BufferedWrite& buffered_write) {
            mhdr->SetIpInNextCmsg(i, buffered_write.self_address);
          });
  
      WriteResult res =
          QuicLinuxSocketUtils::WriteMultiplePackets(fd, &mhdr, num_packets_sent);
      return res;
    }
  
    MockQuicSyscallWrapper mock_syscalls_;
    ScopedGlobalSyscallWrapperOverride syscall_override_{&mock_syscalls_};
  };
  
  void CheckIpAndTtlInCbuf(msghdr* hdr,
                           const void* cbuf,
                           const QuicIpAddress& self_addr,
                           int ttl) {
    const bool is_ipv4 = self_addr.IsIPv4();
    const size_t ip_cmsg_space = is_ipv4 ? kCmsgSpaceForIpv4 : kCmsgSpaceForIpv6;
  
    EXPECT_EQ(cbuf, hdr->msg_control);
    EXPECT_EQ(ip_cmsg_space + CMSG_SPACE(sizeof(uint16_t)), hdr->msg_controllen);
  
    cmsghdr* cmsg = CMSG_FIRSTHDR(hdr);
    EXPECT_EQ(cmsg->cmsg_len, is_ipv4 ? CMSG_LEN(sizeof(in_pktinfo))
                                      : CMSG_LEN(sizeof(in6_pktinfo)));
    EXPECT_EQ(cmsg->cmsg_level, is_ipv4 ? IPPROTO_IP : IPPROTO_IPV6);
    EXPECT_EQ(cmsg->cmsg_type, is_ipv4 ? IP_PKTINFO : IPV6_PKTINFO);
  
    const std::string& self_addr_str = self_addr.ToPackedString();
    if (is_ipv4) {
      in_pktinfo* pktinfo = reinterpret_cast<in_pktinfo*>(CMSG_DATA(cmsg));
      EXPECT_EQ(0, memcmp(&pktinfo->ipi_spec_dst, self_addr_str.c_str(),
                          self_addr_str.length()));
    } else {
      in6_pktinfo* pktinfo = reinterpret_cast<in6_pktinfo*>(CMSG_DATA(cmsg));
      EXPECT_EQ(0, memcmp(&pktinfo->ipi6_addr, self_addr_str.c_str(),
                          self_addr_str.length()));
    }
  
    cmsg = CMSG_NXTHDR(hdr, cmsg);
    EXPECT_EQ(cmsg->cmsg_len, CMSG_LEN(sizeof(int)));
    EXPECT_EQ(cmsg->cmsg_level, is_ipv4 ? IPPROTO_IP : IPPROTO_IPV6);
    EXPECT_EQ(cmsg->cmsg_type, is_ipv4 ? IP_TTL : IPV6_HOPLIMIT);
    EXPECT_EQ(ttl, *reinterpret_cast<int*>(CMSG_DATA(cmsg)));
  
    EXPECT_EQ(nullptr, CMSG_NXTHDR(hdr, cmsg));
  }
  
  void CheckMsghdrWithoutCbuf(const msghdr* hdr,
                              const void* buffer,
                              size_t buf_len,
                              const QuicSocketAddress& peer_addr) {
    EXPECT_EQ(
        peer_addr.host().IsIPv4() ? sizeof(sockaddr_in) : sizeof(sockaddr_in6),
        hdr->msg_namelen);
    sockaddr_storage peer_generic_addr = peer_addr.generic_address();
    EXPECT_EQ(0, memcmp(hdr->msg_name, &peer_generic_addr, hdr->msg_namelen));
    EXPECT_EQ(1u, hdr->msg_iovlen);
    EXPECT_EQ(buffer, hdr->msg_iov->iov_base);
    EXPECT_EQ(buf_len, hdr->msg_iov->iov_len);
    EXPECT_EQ(0, hdr->msg_flags);
    EXPECT_EQ(nullptr, hdr->msg_control);
    EXPECT_EQ(0u, hdr->msg_controllen);
  }
  
  void CheckIpAndGsoSizeInCbuf(msghdr* hdr,
                               const void* cbuf,
                               const QuicIpAddress& self_addr,
                               uint16_t gso_size) {
    const bool is_ipv4 = self_addr.IsIPv4();
    const size_t ip_cmsg_space = is_ipv4 ? kCmsgSpaceForIpv4 : kCmsgSpaceForIpv6;
  
    EXPECT_EQ(cbuf, hdr->msg_control);
    EXPECT_EQ(ip_cmsg_space + CMSG_SPACE(sizeof(uint16_t)), hdr->msg_controllen);
  
    cmsghdr* cmsg = CMSG_FIRSTHDR(hdr);
    EXPECT_EQ(cmsg->cmsg_len, is_ipv4 ? CMSG_LEN(sizeof(in_pktinfo))
                                      : CMSG_LEN(sizeof(in6_pktinfo)));
    EXPECT_EQ(cmsg->cmsg_level, is_ipv4 ? IPPROTO_IP : IPPROTO_IPV6);
    EXPECT_EQ(cmsg->cmsg_type, is_ipv4 ? IP_PKTINFO : IPV6_PKTINFO);
  
    const std::string& self_addr_str = self_addr.ToPackedString();
    if (is_ipv4) {
      in_pktinfo* pktinfo = reinterpret_cast<in_pktinfo*>(CMSG_DATA(cmsg));
      EXPECT_EQ(0, memcmp(&pktinfo->ipi_spec_dst, self_addr_str.c_str(),
                          self_addr_str.length()));
    } else {
      in6_pktinfo* pktinfo = reinterpret_cast<in6_pktinfo*>(CMSG_DATA(cmsg));
      EXPECT_EQ(0, memcmp(&pktinfo->ipi6_addr, self_addr_str.c_str(),
                          self_addr_str.length()));
    }
  
    cmsg = CMSG_NXTHDR(hdr, cmsg);
    EXPECT_EQ(cmsg->cmsg_len, CMSG_LEN(sizeof(uint16_t)));
    EXPECT_EQ(cmsg->cmsg_level, SOL_UDP);
    EXPECT_EQ(cmsg->cmsg_type, UDP_SEGMENT);
    EXPECT_EQ(gso_size, *reinterpret_cast<uint16_t*>(CMSG_DATA(cmsg)));
  
    EXPECT_EQ(nullptr, CMSG_NXTHDR(hdr, cmsg));
  }
  
  TEST_F(QuicLinuxSocketUtilsTest, QuicMsgHdr) {
    QuicSocketAddress peer_addr(QuicIpAddress::Loopback4(), 1234);
    char packet_buf[1024];
  
    QuicMsgHdr quic_hdr(packet_buf, sizeof(packet_buf), peer_addr, nullptr, 0);
    CheckMsghdrWithoutCbuf(quic_hdr.hdr(), packet_buf, sizeof(packet_buf),
                           peer_addr);
  
    for (bool is_ipv4 : {true, false}) {
      QuicIpAddress self_addr =
          is_ipv4 ? QuicIpAddress::Loopback4() : QuicIpAddress::Loopback6();
      char cbuf[kCmsgSpaceForIp + kCmsgSpaceForTTL];
      QuicMsgHdr quic_hdr(packet_buf, sizeof(packet_buf), peer_addr, cbuf,
                          sizeof(cbuf));
      msghdr* hdr = const_cast<msghdr*>(quic_hdr.hdr());
  
      EXPECT_EQ(nullptr, hdr->msg_control);
      EXPECT_EQ(0u, hdr->msg_controllen);
  
      quic_hdr.SetIpInNextCmsg(self_addr);
      EXPECT_EQ(cbuf, hdr->msg_control);
      const size_t ip_cmsg_space =
          is_ipv4 ? kCmsgSpaceForIpv4 : kCmsgSpaceForIpv6;
      EXPECT_EQ(ip_cmsg_space, hdr->msg_controllen);
  
      if (is_ipv4) {
        *quic_hdr.GetNextCmsgData<int>(IPPROTO_IP, IP_TTL) = 32;
      } else {
        *quic_hdr.GetNextCmsgData<int>(IPPROTO_IPV6, IPV6_HOPLIMIT) = 32;
      }
  
      CheckIpAndTtlInCbuf(hdr, cbuf, self_addr, 32);
    }
  }
  
  TEST_F(QuicLinuxSocketUtilsTest, QuicMMsgHdr) {
    QuicCircularDeque<BufferedWrite> buffered_writes;
    char packet_buf1[1024];
    char packet_buf2[512];
    buffered_writes.emplace_back(
        packet_buf1, sizeof(packet_buf1), QuicIpAddress::Loopback4(),
        QuicSocketAddress(QuicIpAddress::Loopback4(), 4));
    buffered_writes.emplace_back(
        packet_buf2, sizeof(packet_buf2), QuicIpAddress::Loopback6(),
        QuicSocketAddress(QuicIpAddress::Loopback6(), 6));
  
    QuicMMsgHdr quic_mhdr_without_cbuf(buffered_writes.begin(),
                                       buffered_writes.end(), 0, nullptr);
    for (size_t i = 0; i < buffered_writes.size(); ++i) {
      const BufferedWrite& bw = buffered_writes[i];
      CheckMsghdrWithoutCbuf(&quic_mhdr_without_cbuf.mhdr()[i].msg_hdr, bw.buffer,
                             bw.buf_len, bw.peer_address);
    }
  
    QuicMMsgHdr quic_mhdr_with_cbuf(
        buffered_writes.begin(), buffered_writes.end(),
        kCmsgSpaceForIp + kCmsgSpaceForSegmentSize,
        [](QuicMMsgHdr* mhdr, int i, const BufferedWrite& buffered_write) {
          mhdr->SetIpInNextCmsg(i, buffered_write.self_address);
          *mhdr->GetNextCmsgData<uint16_t>(i, SOL_UDP, UDP_SEGMENT) = 1300;
        });
    for (size_t i = 0; i < buffered_writes.size(); ++i) {
      const BufferedWrite& bw = buffered_writes[i];
      msghdr* hdr = &quic_mhdr_with_cbuf.mhdr()[i].msg_hdr;
      CheckIpAndGsoSizeInCbuf(hdr, hdr->msg_control, bw.self_address, 1300);
    }
  }
  
  TEST_F(QuicLinuxSocketUtilsTest, WriteMultiplePackets_NoPacketsToSend) {
    int num_packets_sent;
    QuicCircularDeque<BufferedWrite> buffered_writes;
  
    EXPECT_CALL(mock_syscalls_, Sendmmsg(_, _, _, _)).Times(0);
  
    EXPECT_EQ(WriteResult(WRITE_STATUS_ERROR, EINVAL),
              TestWriteMultiplePackets(1, buffered_writes.begin(),
                                       buffered_writes.end(), &num_packets_sent));
  }
  
  TEST_F(QuicLinuxSocketUtilsTest, WriteMultiplePackets_WriteBlocked) {
    int num_packets_sent;
    QuicCircularDeque<BufferedWrite> buffered_writes;
    buffered_writes.emplace_back(nullptr, 0, QuicIpAddress(),
                                 QuicSocketAddress(QuicIpAddress::Any4(), 0));
  
    EXPECT_CALL(mock_syscalls_, Sendmmsg(_, _, _, _))
        .WillOnce(Invoke([](int /*fd*/, mmsghdr* /*msgvec*/,
                            unsigned int /*vlen*/, int /*flags*/) {
          errno = EWOULDBLOCK;
          return -1;
        }));
  
    EXPECT_EQ(WriteResult(WRITE_STATUS_BLOCKED, EWOULDBLOCK),
              TestWriteMultiplePackets(1, buffered_writes.begin(),
                                       buffered_writes.end(), &num_packets_sent));
    EXPECT_EQ(0, num_packets_sent);
  }
  
  TEST_F(QuicLinuxSocketUtilsTest, WriteMultiplePackets_WriteError) {
    int num_packets_sent;
    QuicCircularDeque<BufferedWrite> buffered_writes;
    buffered_writes.emplace_back(nullptr, 0, QuicIpAddress(),
                                 QuicSocketAddress(QuicIpAddress::Any4(), 0));
  
    EXPECT_CALL(mock_syscalls_, Sendmmsg(_, _, _, _))
        .WillOnce(Invoke([](int /*fd*/, mmsghdr* /*msgvec*/,
                            unsigned int /*vlen*/, int /*flags*/) {
          errno = EPERM;
          return -1;
        }));
  
    EXPECT_EQ(WriteResult(WRITE_STATUS_ERROR, EPERM),
              TestWriteMultiplePackets(1, buffered_writes.begin(),
                                       buffered_writes.end(), &num_packets_sent));
    EXPECT_EQ(0, num_packets_sent);
  }
  
  TEST_F(QuicLinuxSocketUtilsTest, WriteMultiplePackets_WriteSuccess) {
    int num_packets_sent;
    QuicCircularDeque<BufferedWrite> buffered_writes;
    const int kNumBufferedWrites = 10;
    static_assert(kNumBufferedWrites < 256, "Must be less than 256");
    std::vector<std::string> buffer_holder;
    for (int i = 0; i < kNumBufferedWrites; ++i) {
      size_t buf_len = (i + 1) * 2;
      std::ostringstream buffer_ostream;
      while (buffer_ostream.str().length() < buf_len) {
        buffer_ostream << i;
      }
      buffer_holder.push_back(buffer_ostream.str().substr(0, buf_len - 1) + '$');
  
      buffered_writes.emplace_back(buffer_holder.back().data(), buf_len,
                                   QuicIpAddress(),
                                   QuicSocketAddress(QuicIpAddress::Any4(), 0));
  
      // Leave the first self_address uninitialized.
      if (i != 0) {
        ASSERT_TRUE(buffered_writes.back().self_address.FromString("127.0.0.1"));
      }
  
      std::ostringstream peer_ip_ostream;
      QuicIpAddress peer_ip_address;
      peer_ip_ostream << "127.0.1." << i + 1;
      ASSERT_TRUE(peer_ip_address.FromString(peer_ip_ostream.str()));
      buffered_writes.back().peer_address =
          QuicSocketAddress(peer_ip_address, i + 1);
    }
  
    InSequence s;
  
    for (int expected_num_packets_sent : {1, 2, 3, 10}) {
      SCOPED_TRACE(testing::Message()
                   << "expected_num_packets_sent=" << expected_num_packets_sent);
      EXPECT_CALL(mock_syscalls_, Sendmmsg(_, _, _, _))
          .WillOnce(Invoke(
              [&](int /*fd*/, mmsghdr* msgvec, unsigned int vlen, int /*flags*/) {
                EXPECT_LE(static_cast<unsigned int>(expected_num_packets_sent),
                          vlen);
                for (unsigned int i = 0; i < vlen; ++i) {
                  const BufferedWrite& buffered_write = buffered_writes[i];
                  const msghdr& hdr = msgvec[i].msg_hdr;
                  EXPECT_EQ(1u, hdr.msg_iovlen);
                  EXPECT_EQ(buffered_write.buffer, hdr.msg_iov->iov_base);
                  EXPECT_EQ(buffered_write.buf_len, hdr.msg_iov->iov_len);
                  sockaddr_storage expected_peer_address =
                      buffered_write.peer_address.generic_address();
                  EXPECT_EQ(0, memcmp(&expected_peer_address, hdr.msg_name,
                                      sizeof(sockaddr_storage)));
                  EXPECT_EQ(buffered_write.self_address.IsInitialized(),
                            hdr.msg_control != nullptr);
                }
                return expected_num_packets_sent;
              }))
          .RetiresOnSaturation();
  
      int expected_bytes_written = 0;
      for (auto it = buffered_writes.cbegin();
           it != buffered_writes.cbegin() + expected_num_packets_sent; ++it) {
        expected_bytes_written += it->buf_len;
      }
  
      EXPECT_EQ(
          WriteResult(WRITE_STATUS_OK, expected_bytes_written),
          TestWriteMultiplePackets(1, buffered_writes.cbegin(),
                                   buffered_writes.cend(), &num_packets_sent));
      EXPECT_EQ(expected_num_packets_sent, num_packets_sent);
    }
  }
  
  }  // namespace
  }  // namespace test
  }  // namespace quic
  