/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <string.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netdb.h>

#include "mozilla/DebugOnly.h"
#include "mozilla/ScopeExit.h"

#include "NetworkInfoServiceImpl.h"

namespace mozilla::net {

static nsresult ListInterfaceAddresses(int aFd, const char* aInterface,
                                       AddrMapType& aAddrMap);

nsresult DoListAddresses(AddrMapType& aAddrMap) {
  int fd = socket(AF_INET, SOCK_DGRAM, 0);
  if (fd < 0) {
    return NS_ERROR_FAILURE;
  }

  auto autoCloseSocket = MakeScopeExit([&] { close(fd); });

  struct ifconf ifconf {};
  /* 16k of space should be enough to list all interfaces.  Worst case, if it's
   * not then we will error out and fail to list addresses.  This should only
   * happen on pathological machines with way too many interfaces.
   */
  char buf[16384];

  ifconf.ifc_len = sizeof(buf);
  ifconf.ifc_buf = buf;
  if (ioctl(fd, SIOCGIFCONF, &ifconf) != 0) {
    return NS_ERROR_FAILURE;
  }

  struct ifreq* ifreq = ifconf.ifc_req;
  int i = 0;
  while (i < ifconf.ifc_len) {
    size_t len = sizeof(struct ifreq);

    DebugOnly<nsresult> rv =
        ListInterfaceAddresses(fd, ifreq->ifr_name, aAddrMap);
    NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "ListInterfaceAddresses failed");

    ifreq = (struct ifreq*)((char*)ifreq + len);
    i += len;
  }

  return NS_OK;
}

static nsresult ListInterfaceAddresses(int aFd, const char* aInterface,
                                       AddrMapType& aAddrMap) {
  struct ifreq ifreq {};
  memset(&ifreq, 0, sizeof(struct ifreq));
  strncpy(ifreq.ifr_name, aInterface, IFNAMSIZ - 1);
  if (ioctl(aFd, SIOCGIFADDR, &ifreq) != 0) {
    return NS_ERROR_FAILURE;
  }

  char host[128];
  switch (ifreq.ifr_addr.sa_family) {
    case AF_INET:
    case AF_INET6:
      getnameinfo(&ifreq.ifr_addr, sizeof(ifreq.ifr_addr), host, sizeof(host),
                  nullptr, 0, NI_NUMERICHOST);
      break;
    case AF_UNSPEC:
      return NS_OK;
    default:
      // Unknown family.
      return NS_OK;
  }

  nsCString ifaceStr;
  ifaceStr.AssignASCII(aInterface);

  nsCString addrStr;
  addrStr.AssignASCII(host);

  aAddrMap.InsertOrUpdate(ifaceStr, addrStr);

  return NS_OK;
}

}  // namespace mozilla::net