netintf.c

Go to the documentation of this file.

/***********************************************************************
 Freeciv - Copyright (C) 1996 - A Kjeldberg, L Gregersen, P Unold
   This program 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; either version 2, or (at your option)
   any later version.
 
   This program 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.
***********************************************************************/
 
/***********************************************************************
  Common network interface.
***********************************************************************/
 
#ifdef HAVE_CONFIG_H
#include <fc_config.h>
#endif
 
#include "fc_prehdrs.h"
 
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#ifdef HAVE_SIGNAL_H
#include <signal.h>
#elif defined(HAVE_SYS_SIGNAL_H)
#include <sys/signal.h>
#endif
#ifdef FREECIV_MSWINDOWS
#include <windows.h>   /* GetTempPath */
#endif
 
/* utility */
#include "bugs.h"
#include "fcintl.h"
#include "log.h"
#include "mem.h"
#include "support.h"
 
#include "netintf.h"
 
#ifndef INADDR_NONE
#define INADDR_NONE 0xffffffff
#endif
 
#ifdef HAVE_GETADDRINFO
#ifdef AI_NUMERICSERV
#define FC_AI_NUMERICSERV AI_NUMERICSERV
#else  /* AI_NUMERICSERV */
#define FC_AI_NUMERICSERV 0
#endif /* AI_NUMERICSERV */
#endif /* HAVE_GETADDRINFO */
 
#ifdef FREECIV_HAVE_WINSOCK
/*********************************************************************/
static void set_socket_errno(void)
{
  int err = WSAGetLastError();
 
  switch (err) {
    /* These have mappings to symbolic errno names in net_types.h */
  case WSAEINTR:
  case WSAEINPROGRESS:
  case WSAEWOULDBLOCK:
  case WSAECONNRESET:
  case WSAECONNREFUSED:
  case WSAEADDRNOTAVAIL:
  case WSAETIMEDOUT:
  case WSAECONNABORTED:
  case WSAENOTSOCK:
    errno = err;
    return;
  default:
    bugreport_request("Missing errno mapping for Winsock error #%d.", err);
 
    errno = 0;
  }
}
#endif /* FREECIV_HAVE_WINSOCK */
 
/*********************************************************************/
int fc_connect(int sockfd, const struct sockaddr *serv_addr, socklen_t addrlen)
{
  int result;
 
  result = connect(sockfd, serv_addr, addrlen);
 
#ifdef FREECIV_HAVE_WINSOCK
  if (result == -1) {
    set_socket_errno();
  }
#endif /* FREECIV_HAVE_WINSOCK */
 
  return result;
}
 
/*********************************************************************/
int fc_select(int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
              fc_timeval *timeout)
{
  int result;
 
  result = select(n, readfds, writefds, exceptfds, timeout);
 
#ifdef FREECIV_HAVE_WINSOCK
  if (result == -1) {
    set_socket_errno();
  }
#endif /* FREECIV_HAVE_WINSOCK */
 
  return result;
}
 
/*********************************************************************/
int fc_readsocket(int sock, void *buf, size_t size)
{
  int result;
 
#ifdef FREECIV_HAVE_WINSOCK
  result = recv(sock, buf, size, 0);
  if (result == -1) {
    set_socket_errno();
  }
#else  /* FREECIV_HAVE_WINSOCK */
  result = read(sock, buf, size);
#endif /* FREECIV_HAVE_WINSOCK */
 
  return result;
}
 
/*********************************************************************/
int fc_writesocket(int sock, const void *buf, size_t size)
{
  int result;
 
#ifdef FREECIV_HAVE_WINSOCK
  result = send(sock, buf, size, 0);
  if (result == -1) {
    set_socket_errno();
  }
#else  /* FREECIV_HAVE_WINSOCK */
#  ifdef MSG_NOSIGNAL
  result = send(sock, buf, size, MSG_NOSIGNAL);
#  else  /* MSG_NOSIGNAL */
  result = write(sock, buf, size);
#  endif /* MSG_NOSIGNAL */
#endif /* FREECIV_HAVE_WINSOCK */
 
  return result;
}
 
/*********************************************************************/
void fc_closesocket(int sock)
{
#ifdef FREECIV_HAVE_WINSOCK
  closesocket(sock);
#else
  close(sock);
#endif
}
 
/*********************************************************************/
void fc_init_network(void)
{
#ifdef FREECIV_HAVE_WINSOCK
  WSADATA wsa;
 
  if (WSAStartup(MAKEWORD(1, 1), &wsa) != 0) {
    log_error("no usable WINSOCK.DLL: %s", fc_strerror(fc_get_errno()));
  }
#endif /* FREECIV_HAVE_WINSOCK */
 
  /* broken pipes are ignored. */
#ifdef HAVE_SIGPIPE
  (void) signal(SIGPIPE, SIG_IGN);
#endif
}
 
/*********************************************************************/
void fc_shutdown_network(void)
{
#ifdef FREECIV_HAVE_WINSOCK
  WSACleanup();
#endif
}
 
/*********************************************************************/
void fc_nonblock(int sockfd)
{
#ifdef NONBLOCKING_SOCKETS
#ifdef FREECIV_HAVE_WINSOCK
#ifdef __LP64__
  unsigned b = 1;
#else  /* __LP64__ */
  u_long b = 1;
#endif /* __LP64__ */
 
  ioctlsocket(sockfd, FIONBIO, &b);
#else  /* FREECIV_HAVE_WINSOCK */
#ifdef HAVE_FCNTL
  int f_set;
 
  if ((f_set = fcntl(sockfd, F_GETFL)) == -1) {
    log_error("fcntl F_GETFL failed: %s", fc_strerror(fc_get_errno()));
  }
 
  f_set |= O_NONBLOCK;
 
  if (fcntl(sockfd, F_SETFL, f_set) == -1) {
    log_error("fcntl F_SETFL failed: %s", fc_strerror(fc_get_errno()));
  }
#else  /* HAVE_FCNTL */
#ifdef HAVE_IOCTL
  long value = 1;
 
  if (ioctl(sockfd, FIONBIO, (char*)&value) == -1) {
    log_error("ioctl failed: %s", fc_strerror(fc_get_errno()));
  }
#endif /* HAVE_IOCTL */
#endif /* HAVE_FCNTL */
#endif /* FREECIV_HAVE_WINSOCK */
#else  /* NONBLOCKING_SOCKETS */
  log_warn("NONBLOCKING_SOCKETS not available");
#endif /* NONBLOCKING_SOCKETS */
}
 
/*********************************************************************/
void sockaddr_debug(union fc_sockaddr *addr, enum log_level lvl)
{
#ifdef FREECIV_IPV6_SUPPORT
  char buf[INET6_ADDRSTRLEN] = "Unknown";
 
  if (addr->saddr.sa_family == AF_INET6) {
    inet_ntop(AF_INET6, &addr->saddr_in6.sin6_addr, buf, INET6_ADDRSTRLEN);
    log_base(lvl, "Host: %s, Port: %d (IPv6)",
             buf, ntohs(addr->saddr_in6.sin6_port));
    return;
  } else if (addr->saddr.sa_family == AF_INET) {
    inet_ntop(AF_INET, &addr->saddr_in4.sin_addr, buf, INET_ADDRSTRLEN);
    log_base(lvl, "Host: %s, Port: %d (IPv4)",
             buf, ntohs(addr->saddr_in4.sin_port));
    return;
  }
#else  /* IPv6 support */
  if (addr->saddr.sa_family == AF_INET) {
    char *buf;
 
    buf = inet_ntoa(addr->saddr_in4.sin_addr);
 
    log_base(lvl, "Host: %s, Port: %d",
             buf, ntohs(addr->saddr_in4.sin_port));
 
    return;
  }
#endif /* IPv6 support */
 
  log_error("Unsupported address family in sockaddr_debug()");
}
 
/*********************************************************************/
int sockaddr_size(union fc_sockaddr *addr)
{
#ifdef FREECIV_MSWINDOWS
  return sizeof(*addr);
#else
#ifdef FREECIV_IPV6_SUPPORT
  if (addr->saddr.sa_family == AF_INET6) {
    return sizeof(addr->saddr_in6);
  } else
#endif /* FREECIV_IPV6_SUPPORT */
  if (addr->saddr.sa_family == AF_INET) {
    return sizeof(addr->saddr_in4);
  } else {
    fc_assert(FALSE);
 
    log_error("Unsupported address family in sockaddr_size()");
 
    return 0;
  }
#endif /* FREECIV_MSWINDOWS */
}
 
/*********************************************************************/
bool sockaddr_ipv6(union fc_sockaddr *addr)
{
#ifdef FREECIV_IPV6_SUPPORT
  if (addr->saddr.sa_family == AF_INET6) {
    return TRUE;
  }
#endif /* IPv6 support */
 
  return FALSE;
}
 
#ifdef HAVE_GETADDRINFO
/*********************************************************************/
static struct fc_sockaddr_list *net_lookup_getaddrinfo(const char *name,
                                                       int port,
                                                       enum fc_addr_family family)
{
  struct addrinfo hints;
  struct addrinfo *res;
  int err;
  char servname[8];
  int gafam;
  struct fc_sockaddr_list *addrs =
      fc_sockaddr_list_new_full((fc_sockaddr_list_free_fn_t) free);
 
  switch (family) {
    case FC_ADDR_IPV4:
      gafam = AF_INET;
      break;
    case FC_ADDR_IPV6:
      gafam = AF_INET6;
      break;
    case FC_ADDR_ANY:
#ifndef FREECIV_IPV6_SUPPORT
      gafam = AF_INET;
#else
      gafam = AF_UNSPEC;
#endif
      break;
    default:
      fc_assert(FALSE);
 
      return addrs;
  }
 
  /* Convert port to string for getaddrinfo() */
  fc_snprintf(servname, sizeof(servname), "%d", port);
 
  /* Use getaddrinfo() to lookup IPv6 addresses */
  memset(&hints, 0, sizeof(hints));
  hints.ai_family = gafam;
  hints.ai_socktype = SOCK_DGRAM; /* any type that uses sin6_port */
  hints.ai_flags = AI_PASSIVE | FC_AI_NUMERICSERV;
  err = getaddrinfo(name, servname, &hints, &res);
 
  if (err == 0) {
    struct addrinfo *current = res;
 
    while (current != nullptr) {
      union fc_sockaddr *caddr;
 
      fc_assert_action(current->ai_addrlen <= sizeof(*caddr), continue);
      caddr = fc_malloc(sizeof(*caddr));
      memcpy(caddr, current->ai_addr, current->ai_addrlen);
 
      fc_sockaddr_list_append(addrs, caddr);
 
      current = current->ai_next;
    }
    freeaddrinfo(res);
  }
 
  return addrs;
}
#endif /* HAVE_GETADDRINFO */
 
/*********************************************************************/
struct fc_sockaddr_list *net_lookup_service(const char *name, int port,
                                            enum fc_addr_family family)
{
  /* IPv6-enabled Freeciv always has HAVE_GETADDRINFO, IPv4-only Freeciv not
   * necessarily */
#ifdef HAVE_GETADDRINFO
  return net_lookup_getaddrinfo(name, port, family);
#else  /* HAVE_GETADDRINFO */
 
  struct sockaddr_in *sock4;
  struct hostent *hp;
  struct fc_sockaddr_list *addrs = fc_sockaddr_list_new();
  union fc_sockaddr *result = fc_malloc(sizeof(*result));
 
  sock4 = &result->saddr_in4;
 
  fc_assert(family != FC_ADDR_IPV6);
 
  result->saddr.sa_family = AF_INET;
  sock4->sin_port = htons(port);
 
  if (!name) {
    sock4->sin_addr.s_addr = htonl(INADDR_ANY);
    fc_sockaddr_list_append(addrs, result);
 
    return addrs;
  }
 
  if (fc_inet_aton(name, &sock4->sin_addr, FALSE)) {
    fc_sockaddr_list_append(addrs, result);
 
    return addrs;
  }
 
  hp = gethostbyname(name);
  if (!hp || hp->h_addrtype != AF_INET) {
    FC_FREE(result);
 
    return addrs;
  }
 
  memcpy(&sock4->sin_addr, hp->h_addr, hp->h_length);
  fc_sockaddr_list_append(addrs, result);
 
  return addrs;
 
#endif /* !HAVE_GETADDRINFO */
 
}
 
/*********************************************************************/
bool fc_inet_aton(const char *cp, struct in_addr *inp, bool addr_none_ok)
{
#ifdef FREECIV_IPV6_SUPPORT
  /* Use inet_pton() */
  if (!inet_pton(AF_INET, cp, &inp->s_addr)) {
    return FALSE;
  }
#else  /* IPv6 Support */
#ifdef HAVE_INET_ATON
  if (!inet_aton(cp, inp)) {
    return FALSE;
  }
#else  /* HAVE_INET_ATON */
  inp->s_addr = inet_addr(cp);
  if (!addr_none_ok && inp->s_addr == INADDR_NONE) {
    return FALSE;
  }
#endif /* HAVE_INET_ATON */
#endif /* IPv6 Support */
 
  return TRUE;
}
 
/*********************************************************************/
fz_FILE *fc_querysocket(int sock, void *buf, size_t size)
{
  FILE *fp;
 
#ifdef HAVE_FDOPEN
  fp = fdopen(sock, "r+b");
 
  if (fp == nullptr) {
    log_error("socket %d: failed to fdopen()", sock);
 
    return nullptr;
  }
 
  if (fwrite(buf, 1, size, fp) != size) {
    log_error("socket %d: write error", sock);
  }
  fflush(fp);
 
  /* We don't use fc_closesocket() on sock here since when fp is closed,
   * sock will also be closed. fdopen() doesn't dup the socket descriptor. */
#else  /* HAVE_FDOPEN */
  {
    char tmp[4096];
    int n;
 
#ifdef FREECIV_MSWINDOWS
    /* tmpfile() in mingw attempts to make a temp file in the root directory
     * of the current drive, which we may not have write access to. */
    {
      char filename[MAX_PATH];
 
      GetTempPath(sizeof(filename), filename);
      sz_strlcat(filename, "fctmp");
 
      fp = fc_fopen(filename, "w+b");
    }
#else  /* FREECIV_MSWINDOWS */
 
    fp = tmpfile();
 
#endif /* FREECIV_MSWINDOWS */
 
    if (fp == nullptr) {
      return nullptr;
    }
 
    fc_writesocket(sock, buf, size);
 
    while ((n = fc_readsocket(sock, tmp, sizeof(tmp))) > 0) {
      if (fwrite(tmp, 1, n, fp) != n) {
        log_error("socket %d: write error", sock);
      }
    }
    fflush(fp);
 
    fc_closesocket(sock);
 
    rewind(fp);
  }
#endif /* HAVE_FDOPEN */
 
  return fz_from_stream(fp);
}
 
/*********************************************************************/
int find_next_free_port(int starting_port, int highest_port,
                        enum fc_addr_family family,
                        char *net_interface, bool not_avail_ok)
{
  int port;
  int s;
  int gafamily;
  bool found = FALSE;
 
#ifndef FREECIV_IPV6_SUPPORT
  fc_assert(family == FC_ADDR_IPV4 || family == FC_ADDR_ANY);
#endif
 
  switch (family) {
   case FC_ADDR_IPV4:
     gafamily = AF_INET;
     break;
#ifdef FREECIV_IPV6_SUPPORT
   case FC_ADDR_IPV6:
     gafamily = AF_INET6;
     break;
#endif /* FREECIV_IPV6_SUPPORT */
   case FC_ADDR_ANY:
     gafamily = AF_UNSPEC;
     break;
   default:
     fc_assert(FALSE);
     log_error("Port from unsupported address family requested!");
 
     return -1;
  }
 
  for (port = starting_port; !found && highest_port > port; port++) {
    /* HAVE_GETADDRINFO implies IPv6 support */
#ifdef HAVE_GETADDRINFO
    struct addrinfo hints;
    int err;
    char servname[8];
    struct addrinfo *res;
 
    fc_snprintf(servname, sizeof(servname), "%d", port);
 
    memset(&hints, 0, sizeof(hints));
    hints.ai_family = gafamily;
    hints.ai_socktype = SOCK_DGRAM;
    hints.ai_flags = AI_PASSIVE | FC_AI_NUMERICSERV;
 
    err = getaddrinfo(net_interface, servname, &hints, &res);
    if (!err) {
      struct addrinfo *current = res;
      bool unusable = FALSE;
 
      while (current != nullptr && !unusable) {
        s = socket(current->ai_family, SOCK_STREAM, 0);
 
        if (s == -1) {
          log_error("socket(): %s", fc_strerror(fc_get_errno()));
        } else {
          if (bind(s, current->ai_addr, current->ai_addrlen) != 0) {
            if (!not_avail_ok || fc_get_errno() != EADDRNOTAVAIL) {
              unusable = TRUE;
            }
          }
        }
        current = current->ai_next;
        fc_closesocket(s);
      }
 
      freeaddrinfo(res);
 
      if (!unusable && res != nullptr) {
        found = TRUE;
      }
    }
#else /* HAVE_GETADDRINFO */
    union fc_sockaddr tmp;
    struct sockaddr_in *sock4;
 
    s = socket(gafamily, SOCK_STREAM, 0);
 
    sock4 = &tmp.saddr_in4;
    memset(&tmp, 0, sizeof(tmp));
    sock4->sin_family = AF_INET;
    sock4->sin_port = htons(port);
    if (net_interface != nullptr) {
      if (!fc_inet_aton(net_interface, &sock4->sin_addr, FALSE)) {
        struct hostent *hp;
 
        hp = gethostbyname(net_interface);
        if (hp == nullptr) {
          log_error("No hostent for %s!", net_interface);
 
          return -1;
        }
        if (hp->h_addrtype != AF_INET) {
          log_error("Requested IPv4 address for %s, got something else! (%d)",
                    net_interface, hp->h_addrtype);
 
          return -1;
        }
 
        memcpy(&sock4->sin_addr, hp->h_addr, hp->h_length);
      }
    } else {
      sock4->sin_addr.s_addr = htonl(INADDR_ANY);
    }
 
    if (bind(s, &tmp.saddr, sockaddr_size(&tmp)) == 0) {
      found = TRUE;
    }
 
    fc_closesocket(s);
#endif /* HAVE_GETADDRINFO */
  }
 
  if (!found) {
    log_error("None of the ports %d - %d is available.",
              starting_port, highest_port);
 
    return -1;
  }
 
  /* Rollback the last increment from the loop, back to the port
   * number found to be free. */
  port--;
 
  return port;
}
 
/*********************************************************************/
int addr_family_for_announce_type(enum announce_type announce)
{
  switch (announce) {
  case ANNOUNCE_IPV6:
    return AF_INET;
  case ANNOUNCE_IPV4:
    return AF_INET;
  case ANNOUNCE_NONE:
    return AF_UNSPEC;
  }
 
  fc_assert(FALSE);
 
  return AF_UNSPEC;
}