#include "test/integration/tcp_dump.h"

#include <sys/types.h>

#include <csignal>

#include <fstream>

#include "envoy/common/platform.h"

#include "source/common/common/assert.h"

#include "source/common/common/fmt.h"

namespace Envoy {

TcpDump::TcpDump(const std::string& path, const std::string& iface,

                 const std::vector<uint32_t>& ports) {

#ifdef WIN32

  ENVOY_LOG_MISC(debug, "tcpdump not supported on windows");

#else

  // Remove any extant pcap file.

  ::unlink(path.c_str());

  // Derive the port filter expression.

  std::string port_expr;

  for (uint32_t port : ports) {

    if (!port_expr.empty()) {

      port_expr += " or ";

    }

    port_expr += "tcp port " + std::to_string(port);

  }

  ENVOY_LOG_MISC(debug, "tcpdumping iface {} to {} with filter \"{}\"", iface, path, port_expr);

  // Fork a child process. We use explicit fork/wait over popen/pclose to gain

  // the ability to send signals to the pid.

  tcpdump_pid_ = ::fork();

  RELEASE_ASSERT(tcpdump_pid_ >= 0, "");

  // execlp in the child process.

  if (tcpdump_pid_ == 0) {

    const int rc = ::execlp("tcpdump", "tcpdump", "-i", iface.c_str(), "-w", path.c_str(),

                            "--immediate-mode", port_expr.c_str(), nullptr);

    if (rc == -1) {

      ::perror("tcpdump");

      exit(1);

    }

  }

  // Wait in parent process until tcpdump is running and has created the pcap

  // file.

  while (true) {

    std::ifstream test_file{path};

    if (test_file.good()) {

      break;

    }

    // If the child died unexpectedly, handle this.

    int status;

    int rc = ::waitpid(tcpdump_pid_, &status, WNOHANG);

    RELEASE_ASSERT(rc != -1, "");

    if (rc > 0) {

      RELEASE_ASSERT(rc == tcpdump_pid_, "");

      RELEASE_ASSERT(WIFEXITED(status), "");

      RELEASE_ASSERT(WEXITSTATUS(status) == 1, "");

      ENVOY_LOG_MISC(debug, "tcpdump exited abnormally");

      tcpdump_pid_ = 0;

      break;

    }

    // Give 50ms sleep.

    ::usleep(50000); // NO_CHECK_FORMAT(real_time)

  }

#endif

}

TcpDump::~TcpDump() {

#ifndef WIN32

  if (tcpdump_pid_ > 0) {

    RELEASE_ASSERT(::kill(tcpdump_pid_, SIGINT) == 0, "");

    int status;

    RELEASE_ASSERT(::waitpid(tcpdump_pid_, &status, 0) != -1, "");

    RELEASE_ASSERT(WIFEXITED(status), "");

    RELEASE_ASSERT(WEXITSTATUS(status) == 0, "");

    ENVOY_LOG_MISC(debug, "tcpdump terminated");

  }

#endif

}

} // namespace Envoy