address.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

#include "../../stdafx.h"

#include "address.h"
#include "../../debug.h"

#include "../../safeguards.h"

const char *NetworkAddress::GetHostname()
{
  if (StrEmpty(this->hostname) && this->address.ss_family != AF_UNSPEC) {
    assert(this->address_length != 0);
    getnameinfo((struct sockaddr *)&this->address, this->address_length, this->hostname, sizeof(this->hostname), nullptr, 0, NI_NUMERICHOST);
  }
  return this->hostname;
}

uint16 NetworkAddress::GetPort() const
{
  switch (this->address.ss_family) {
    case AF_UNSPEC:
    case AF_INET:
      return ntohs(((const struct sockaddr_in *)&this->address)->sin_port);

    case AF_INET6:
      return ntohs(((const struct sockaddr_in6 *)&this->address)->sin6_port);

    default:
      NOT_REACHED();
  }
}

void NetworkAddress::SetPort(uint16 port)
{
  switch (this->address.ss_family) {
    case AF_UNSPEC:
    case AF_INET:
      ((struct sockaddr_in*)&this->address)->sin_port = htons(port);
      break;

    case AF_INET6:
      ((struct sockaddr_in6*)&this->address)->sin6_port = htons(port);
      break;

    default:
      NOT_REACHED();
  }
}

void NetworkAddress::GetAddressAsString(char *buffer, const char *last, bool with_family)
{
  if (this->GetAddress()->ss_family == AF_INET6) buffer = strecpy(buffer, "[", last);
  buffer = strecpy(buffer, this->GetHostname(), last);
  if (this->GetAddress()->ss_family == AF_INET6) buffer = strecpy(buffer, "]", last);
  buffer += seprintf(buffer, last, ":%d", this->GetPort());

  if (with_family) {
    char family;
    switch (this->address.ss_family) {
      case AF_INET:  family = '4'; break;
      case AF_INET6: family = '6'; break;
      default:       family = '?'; break;
    }
    seprintf(buffer, last, " (IPv%c)", family);
  }
}

std::string NetworkAddress::GetAddressAsString(bool with_family)
{
  /* 6 = for the : and 5 for the decimal port number */
  char buf[NETWORK_HOSTNAME_LENGTH + 6 + 7];
  this->GetAddressAsString(buf, lastof(buf), with_family);
  return buf;
}

static SOCKET ResolveLoopProc(addrinfo *runp)
{
  /* We just want the first 'entry', so return a valid socket. */
  return !INVALID_SOCKET;
}

const sockaddr_storage *NetworkAddress::GetAddress()
{
  if (!this->IsResolved()) {
    /* Here we try to resolve a network address. We use SOCK_STREAM as
     * socket type because some stupid OSes, like Solaris, cannot be
     * bothered to implement the specifications and allow '0' as value
     * that means "don't care whether it is SOCK_STREAM or SOCK_DGRAM".
     */
    this->Resolve(this->address.ss_family, SOCK_STREAM, AI_ADDRCONFIG, nullptr, ResolveLoopProc);
    this->resolved = true;
  }
  return &this->address;
}

bool NetworkAddress::IsFamily(int family)
{
  if (!this->IsResolved()) {
    this->Resolve(family, SOCK_STREAM, AI_ADDRCONFIG, nullptr, ResolveLoopProc);
  }
  return this->address.ss_family == family;
}

bool NetworkAddress::IsInNetmask(const char *netmask)
{
  /* Resolve it if we didn't do it already */
  if (!this->IsResolved()) this->GetAddress();

  int cidr = this->address.ss_family == AF_INET ? 32 : 128;

  NetworkAddress mask_address;

  /* Check for CIDR separator */
  const char *chr_cidr = strchr(netmask, '/');
  if (chr_cidr != nullptr) {
    int tmp_cidr = atoi(chr_cidr + 1);

    /* Invalid CIDR, treat as single host */
    if (tmp_cidr > 0 || tmp_cidr < cidr) cidr = tmp_cidr;

    /* Remove the / so that NetworkAddress works on the IP portion */
    std::string ip_str(netmask, chr_cidr - netmask);
    mask_address = NetworkAddress(ip_str.c_str(), 0, this->address.ss_family);
  } else {
    mask_address = NetworkAddress(netmask, 0, this->address.ss_family);
  }

  if (mask_address.GetAddressLength() == 0) return false;

  uint32 *ip;
  uint32 *mask;
  switch (this->address.ss_family) {
    case AF_INET:
      ip = (uint32*)&((struct sockaddr_in*)&this->address)->sin_addr.s_addr;
      mask = (uint32*)&((struct sockaddr_in*)&mask_address.address)->sin_addr.s_addr;
      break;

    case AF_INET6:
      ip = (uint32*)&((struct sockaddr_in6*)&this->address)->sin6_addr;
      mask = (uint32*)&((struct sockaddr_in6*)&mask_address.address)->sin6_addr;
      break;

    default:
      NOT_REACHED();
  }

  while (cidr > 0) {
    uint32 msk = cidr >= 32 ? (uint32)-1 : htonl(-(1 << (32 - cidr)));
    if ((*mask++ & msk) != (*ip++ & msk)) return false;

    cidr -= 32;
  }

  return true;
}

SOCKET NetworkAddress::Resolve(int family, int socktype, int flags, SocketList *sockets, LoopProc func)
{
  struct addrinfo *ai;
  struct addrinfo hints;
  memset(&hints, 0, sizeof (hints));
  hints.ai_family   = family;
  hints.ai_flags    = flags;
  hints.ai_socktype = socktype;

  /* The port needs to be a string. Six is enough to contain all characters + '\0'. */
  char port_name[6];
  seprintf(port_name, lastof(port_name), "%u", this->GetPort());

  bool reset_hostname = false;
  /* Setting both hostname to nullptr and port to 0 is not allowed.
   * As port 0 means bind to any port, the other must mean that
   * we want to bind to 'all' IPs. */
  if (StrEmpty(this->hostname) && this->address_length == 0 && this->GetPort() == 0) {
    reset_hostname = true;
    int fam = this->address.ss_family;
    if (fam == AF_UNSPEC) fam = family;
    strecpy(this->hostname, fam == AF_INET ? "0.0.0.0" : "::", lastof(this->hostname));
  }

  int e = getaddrinfo(StrEmpty(this->hostname) ? nullptr : this->hostname, port_name, &hints, &ai);

  if (reset_hostname) strecpy(this->hostname, "", lastof(this->hostname));

  if (e != 0) {
    if (func != ResolveLoopProc) {
      DEBUG(net, 0, "getaddrinfo for hostname \"%s\", port %s, address family %s and socket type %s failed: %s",
        this->hostname, port_name, AddressFamilyAsString(family), SocketTypeAsString(socktype), FS2OTTD(gai_strerror(e)));
    }
    return INVALID_SOCKET;
  }

  SOCKET sock = INVALID_SOCKET;
  for (struct addrinfo *runp = ai; runp != nullptr; runp = runp->ai_next) {
    /* When we are binding to multiple sockets, make sure we do not
     * connect to one with exactly the same address twice. That's
     * of course totally unneeded ;) */
    if (sockets != nullptr) {
      NetworkAddress address(runp->ai_addr, (int)runp->ai_addrlen);
      if (sockets->Contains(address)) continue;
    }
    sock = func(runp);
    if (sock == INVALID_SOCKET) continue;

    if (sockets == nullptr) {
      this->address_length = (int)runp->ai_addrlen;
      assert(sizeof(this->address) >= runp->ai_addrlen);
      memcpy(&this->address, runp->ai_addr, runp->ai_addrlen);
      break;
    }

    NetworkAddress addr(runp->ai_addr, (int)runp->ai_addrlen);
    (*sockets)[addr] = sock;
    sock = INVALID_SOCKET;
  }
  freeaddrinfo (ai);

  return sock;
}

static SOCKET ConnectLoopProc(addrinfo *runp)
{
  const char *type = NetworkAddress::SocketTypeAsString(runp->ai_socktype);
  const char *family = NetworkAddress::AddressFamilyAsString(runp->ai_family);
  char address[NETWORK_HOSTNAME_LENGTH + 6 + 7];
  NetworkAddress(runp->ai_addr, (int)runp->ai_addrlen).GetAddressAsString(address, lastof(address));

  SOCKET sock = socket(runp->ai_family, runp->ai_socktype, runp->ai_protocol);
  if (sock == INVALID_SOCKET) {
    DEBUG(net, 1, "[%s] could not create %s socket: %s", type, family, strerror(errno));
    return INVALID_SOCKET;
  }

  if (!SetNoDelay(sock)) DEBUG(net, 1, "[%s] setting TCP_NODELAY failed", type);

  if (connect(sock, runp->ai_addr, (int)runp->ai_addrlen) != 0) {
    DEBUG(net, 1, "[%s] could not connect %s socket: %s", type, family, strerror(errno));
    closesocket(sock);
    return INVALID_SOCKET;
  }

  /* Connection succeeded */
  if (!SetNonBlocking(sock)) DEBUG(net, 0, "[%s] setting non-blocking mode failed", type);

  DEBUG(net, 1, "[%s] connected to %s", type, address);

  return sock;
}

SOCKET NetworkAddress::Connect()
{
  DEBUG(net, 1, "Connecting to %s", this->GetAddressAsString().c_str());

  return this->Resolve(AF_UNSPEC, SOCK_STREAM, AI_ADDRCONFIG, nullptr, ConnectLoopProc);
}

static SOCKET ListenLoopProc(addrinfo *runp)
{
  const char *type = NetworkAddress::SocketTypeAsString(runp->ai_socktype);
  const char *family = NetworkAddress::AddressFamilyAsString(runp->ai_family);
  char address[NETWORK_HOSTNAME_LENGTH + 6 + 7];
  NetworkAddress(runp->ai_addr, (int)runp->ai_addrlen).GetAddressAsString(address, lastof(address));

  SOCKET sock = socket(runp->ai_family, runp->ai_socktype, runp->ai_protocol);
  if (sock == INVALID_SOCKET) {
    DEBUG(net, 0, "[%s] could not create %s socket on port %s: %s", type, family, address, strerror(errno));
    return INVALID_SOCKET;
  }

  if (runp->ai_socktype == SOCK_STREAM && !SetNoDelay(sock)) {
    DEBUG(net, 3, "[%s] setting TCP_NODELAY failed for port %s", type, address);
  }

  int on = 1;
  /* The (const char*) cast is needed for windows!! */
  if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (const char*)&on, sizeof(on)) == -1) {
    DEBUG(net, 3, "[%s] could not set reusable %s sockets for port %s: %s", type, family, address, strerror(errno));
  }

#ifndef __OS2__
  if (runp->ai_family == AF_INET6 &&
      setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&on, sizeof(on)) == -1) {
    DEBUG(net, 3, "[%s] could not disable IPv4 over IPv6 on port %s: %s", type, address, strerror(errno));
  }
#endif

  if (bind(sock, runp->ai_addr, (int)runp->ai_addrlen) != 0) {
    DEBUG(net, 1, "[%s] could not bind on %s port %s: %s", type, family, address, strerror(errno));
    closesocket(sock);
    return INVALID_SOCKET;
  }

  if (runp->ai_socktype != SOCK_DGRAM && listen(sock, 1) != 0) {
    DEBUG(net, 1, "[%s] could not listen at %s port %s: %s", type, family, address, strerror(errno));
    closesocket(sock);
    return INVALID_SOCKET;
  }

  /* Connection succeeded */
  if (!SetNonBlocking(sock)) DEBUG(net, 0, "[%s] setting non-blocking mode failed for %s port %s", type, family, address);

  DEBUG(net, 1, "[%s] listening on %s port %s", type, family, address);
  return sock;
}

void NetworkAddress::Listen(int socktype, SocketList *sockets)
{
  assert(sockets != nullptr);

  /* Setting both hostname to nullptr and port to 0 is not allowed.
   * As port 0 means bind to any port, the other must mean that
   * we want to bind to 'all' IPs. */
  if (this->address_length == 0 && this->address.ss_family == AF_UNSPEC &&
      StrEmpty(this->hostname) && this->GetPort() == 0) {
    this->Resolve(AF_INET,  socktype, AI_ADDRCONFIG | AI_PASSIVE, sockets, ListenLoopProc);
    this->Resolve(AF_INET6, socktype, AI_ADDRCONFIG | AI_PASSIVE, sockets, ListenLoopProc);
  } else {
    this->Resolve(AF_UNSPEC, socktype, AI_ADDRCONFIG | AI_PASSIVE, sockets, ListenLoopProc);
  }
}

/* static */ const char *NetworkAddress::SocketTypeAsString(int socktype)
{
  switch (socktype) {
    case SOCK_STREAM: return "tcp";
    case SOCK_DGRAM:  return "udp";
    default:          return "unsupported";
  }
}

/* static */ const char *NetworkAddress::AddressFamilyAsString(int family)
{
  switch (family) {
    case AF_UNSPEC: return "either IPv4 or IPv6";
    case AF_INET:   return "IPv4";
    case AF_INET6:  return "IPv6";
    default:        return "unsupported";
  }
}