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 "../network_internal.h"
#include "../../debug.h"
 
#include "../../safeguards.h"
 
const std::string &NetworkAddress::GetHostname()
{
  if (this->hostname.empty() && this->address.ss_family != AF_UNSPEC) {
    assert(this->address_length != 0);
    char buffer[NETWORK_HOSTNAME_LENGTH];
    getnameinfo((struct sockaddr *)&this->address, this->address_length, buffer, sizeof(buffer), nullptr, 0, NI_NUMERICHOST);
    this->hostname = buffer;
  }
  return this->hostname;
}
 
uint16_t 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_t 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();
  }
}
 
static const char *GetAddressFormatString(uint16_t family, bool with_family)
{
  switch (family) {
    case AF_INET: return with_family ? "{}:{} (IPv4)" : "{}:{}";
    case AF_INET6: return with_family ? "[{}]:{} (IPv6)" : "[{}]:{}";
    default: return with_family ? "{}:{} (IPv?)" : "{}:{}";
  }
}
 
std::string NetworkAddress::GetAddressAsString(bool with_family)
{
  return fmt::format(fmt::runtime(GetAddressFormatString(this->GetAddress()->ss_family, with_family)), this->GetHostname(), this->GetPort());
}
 
static SOCKET ResolveLoopProc(addrinfo *)
{
  /* 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 std::string &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 */
  auto cidr_separator_location = netmask.find('/');
  if (cidr_separator_location != std::string::npos) {
    int tmp_cidr = atoi(netmask.substr(cidr_separator_location + 1).c_str());
 
    /* 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 */
    mask_address = NetworkAddress(netmask.substr(0, cidr_separator_location), 0, this->address.ss_family);
  } else {
    mask_address = NetworkAddress(netmask, 0, this->address.ss_family);
  }
 
  if (mask_address.GetAddressLength() == 0) return false;
 
  uint32_t *ip;
  uint32_t *mask;
  switch (this->address.ss_family) {
    case AF_INET:
      ip = (uint32_t*)&((struct sockaddr_in*)&this->address)->sin_addr.s_addr;
      mask = (uint32_t*)&((struct sockaddr_in*)&mask_address.address)->sin_addr.s_addr;
      break;
 
    case AF_INET6:
      ip = (uint32_t*)&((struct sockaddr_in6*)&this->address)->sin6_addr;
      mask = (uint32_t*)&((struct sockaddr_in6*)&mask_address.address)->sin6_addr;
      break;
 
    default:
      NOT_REACHED();
  }
 
  while (cidr > 0) {
    uint32_t msk = cidr >= 32 ? (uint32_t)-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'. */
  std::string port_name = std::to_string(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 (this->hostname.empty() && this->address_length == 0 && this->GetPort() == 0) {
    reset_hostname = true;
    int fam = this->address.ss_family;
    if (fam == AF_UNSPEC) fam = family;
    this->hostname = fam == AF_INET ? "0.0.0.0" : "::";
  }
 
  static bool _resolve_timeout_error_message_shown = false;
  auto start = std::chrono::steady_clock::now();
  int e = getaddrinfo(this->hostname.empty() ? nullptr : this->hostname.c_str(), port_name.c_str(), &hints, &ai);
  auto end = std::chrono::steady_clock::now();
  std::chrono::seconds duration = std::chrono::duration_cast<std::chrono::seconds>(end - start);
  if (!_resolve_timeout_error_message_shown && duration >= std::chrono::seconds(5)) {
    Debug(net, 0, "getaddrinfo for hostname \"{}\", port {}, address family {} and socket type {} took {} seconds",
        this->hostname, port_name, AddressFamilyAsString(family), SocketTypeAsString(socktype), duration.count());
    Debug(net, 0, "  this is likely an issue in the DNS name resolver's configuration causing it to time out");
    _resolve_timeout_error_message_shown = true;
  }
 
 
  if (reset_hostname) this->hostname.clear();
 
  if (e != 0) {
    if (func != ResolveLoopProc) {
      Debug(net, 0, "getaddrinfo for hostname \"{}\", port {}, address family {} and socket type {} failed: {}",
        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 (std::any_of(sockets->begin(), sockets->end(), [&address](const auto &p) { return p.second == 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);
#ifdef __EMSCRIPTEN__
      /* Emscripten doesn't zero sin_zero, but as we compare addresses
       * to see if they are the same address, we need them to be zero'd.
       * Emscripten is, as far as we know, the only OS not doing this.
       *
       * https://github.com/emscripten-core/emscripten/issues/12998
       */
      if (this->address.ss_family == AF_INET) {
        sockaddr_in *address_ipv4 = (sockaddr_in *)&this->address;
        memset(address_ipv4->sin_zero, 0, sizeof(address_ipv4->sin_zero));
      }
#endif
      break;
    }
 
    NetworkAddress addr(runp->ai_addr, (int)runp->ai_addrlen);
    (*sockets)[sock] = addr;
    sock = INVALID_SOCKET;
  }
  freeaddrinfo (ai);
 
  return sock;
}
 
static SOCKET ListenLoopProc(addrinfo *runp)
{
  std::string address = NetworkAddress(runp->ai_addr, (int)runp->ai_addrlen).GetAddressAsString();
 
  SOCKET sock = socket(runp->ai_family, runp->ai_socktype, runp->ai_protocol);
  if (sock == INVALID_SOCKET) {
    const char *type = NetworkAddress::SocketTypeAsString(runp->ai_socktype);
    const char *family = NetworkAddress::AddressFamilyAsString(runp->ai_family);
    Debug(net, 0, "Could not create {} {} socket: {}", type, family, NetworkError::GetLast().AsString());
    return INVALID_SOCKET;
  }
 
  if (runp->ai_socktype == SOCK_STREAM && !SetNoDelay(sock)) {
    Debug(net, 1, "Setting no-delay mode failed: {}", NetworkError::GetLast().AsString());
  }
 
  if (!SetReusePort(sock)) {
    Debug(net, 0, "Setting reuse-address mode failed: {}", NetworkError::GetLast().AsString());
  }
 
  int on = 1;
  if (runp->ai_family == AF_INET6 &&
      setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&on, sizeof(on)) == -1) {
    Debug(net, 3, "Could not disable IPv4 over IPv6: {}", NetworkError::GetLast().AsString());
  }
 
  if (bind(sock, runp->ai_addr, (int)runp->ai_addrlen) != 0) {
    Debug(net, 0, "Could not bind socket on {}: {}", address, NetworkError::GetLast().AsString());
    closesocket(sock);
    return INVALID_SOCKET;
  }
 
  if (runp->ai_socktype != SOCK_DGRAM && listen(sock, 1) != 0) {
    Debug(net, 0, "Could not listen on socket: {}", NetworkError::GetLast().AsString());
    closesocket(sock);
    return INVALID_SOCKET;
  }
 
  /* Connection succeeded */
 
  if (!SetNonBlocking(sock)) {
    Debug(net, 0, "Setting non-blocking mode failed: {}", NetworkError::GetLast().AsString());
  }
 
  Debug(net, 3, "Listening on {}", address);
  return sock;
}
 
void NetworkAddress::Listen(int socktype, SocketList *sockets)
{
  assert(sockets != nullptr);
 
  /* Setting both hostname to "" 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 &&
      this->hostname.empty() && 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";
  }
}
 
/* static */ NetworkAddress NetworkAddress::GetPeerAddress(SOCKET sock)
{
  sockaddr_storage addr = {};
  socklen_t addr_len = sizeof(addr);
  if (getpeername(sock, (sockaddr *)&addr, &addr_len) != 0) {
    Debug(net, 0, "Failed to get address of the peer: {}", NetworkError::GetLast().AsString());
    return NetworkAddress();
  }
  return NetworkAddress(addr, addr_len);
}
 
/* static */ NetworkAddress NetworkAddress::GetSockAddress(SOCKET sock)
{
  sockaddr_storage addr = {};
  socklen_t addr_len = sizeof(addr);
  if (getsockname(sock, (sockaddr *)&addr, &addr_len) != 0) {
    Debug(net, 0, "Failed to get address of the socket: {}", NetworkError::GetLast().AsString());
    return NetworkAddress();
  }
  return NetworkAddress(addr, addr_len);
}
 
/* static */ const std::string NetworkAddress::GetPeerName(SOCKET sock)
{
  return NetworkAddress::GetPeerAddress(sock).GetAddressAsString();
}
 
/* static */ ServerAddress ServerAddress::Parse(const std::string &connection_string, uint16_t default_port, CompanyID *company_id)
{
  if (connection_string.starts_with("+")) {
    std::string_view invite_code = ParseCompanyFromConnectionString(connection_string, company_id);
    return ServerAddress(SERVER_ADDRESS_INVITE_CODE, std::string(invite_code));
  }
 
  uint16_t port = default_port;
  std::string_view ip = ParseFullConnectionString(connection_string, port, company_id);
  return ServerAddress(SERVER_ADDRESS_DIRECT, std::string(ip) + ":" + std::to_string(port));
}