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network.c

/* X-Chat
 * Copyright (C) 2001 Peter Zelezny.
 *
 * 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 of the License, 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

/* ipv4 and ipv6 networking functions with a common interface */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <glib.h>

#include "../../config.h"                         /* grab USE_IPV6 and LOOKUPD defines */

#define WANTSOCKET
#define WANTARPA
#define WANTDNS
#include "inet.h"

#define NETWORK_PRIVATE
#include "network.h"

#define RAND_INT(n) ((int)(rand() / (RAND_MAX + 1.0) * (n)))


/* ================== COMMON ================= */

static void
net_set_socket_options (int sok)
{
      socklen_t sw;

      sw = 1;
      setsockopt (sok, SOL_SOCKET, SO_REUSEADDR, (char *) &sw, sizeof (sw));
      sw = 1;
      setsockopt (sok, SOL_SOCKET, SO_KEEPALIVE, (char *) &sw, sizeof (sw));
}

char *
net_ip (guint32 addr)
{
      struct in_addr ia;

      ia.s_addr = htonl (addr);
      return inet_ntoa (ia);
}

void
net_store_destroy (netstore * ns)
{
#ifdef USE_IPV6
      if (ns->ip6_hostent)
            freeaddrinfo (ns->ip6_hostent);
#endif
      free (ns);
}

netstore *
net_store_new (void)
{
      netstore *ns;

      ns = malloc (sizeof (netstore));
      memset (ns, 0, sizeof (netstore));

      return ns;
}

#ifndef USE_IPV6

/* =================== IPV4 ================== */

/*
      A note about net_resolve and lookupd:

      Many IRC networks rely on round-robin DNS for load balancing, rotating the list
      of IP address on each query. However, this method breaks when DNS queries are
      cached. Mac OS X and Darwin handle DNS lookups through the lookupd daemon, which
      caches queries in its default configuration: thus, if we always pick the first
      address, we will be stuck with the same host (which might be down!) until the
      TTL reaches 0 or lookupd is reset (typically, at reboot). Therefore, we need to
      pick a random address from the result list, instead of always using the first.
*/

char *
net_resolve (netstore * ns, char *hostname, int port, char **real_host)
{
      ns->ip4_hostent = gethostbyname (hostname);
      if (!ns->ip4_hostent)
            return NULL;

      memset (&ns->addr, 0, sizeof (ns->addr));
#ifdef LOOKUPD
      int count = 0;
      while (ns->ip4_hostent->h_addr_list[count]) count++;
      memcpy (&ns->addr.sin_addr,
                  ns->ip4_hostent->h_addr_list[RAND_INT(count)],
                  ns->ip4_hostent->h_length);
#else
      memcpy (&ns->addr.sin_addr, ns->ip4_hostent->h_addr,
                    ns->ip4_hostent->h_length);
#endif
      ns->addr.sin_port = htons (port);
      ns->addr.sin_family = AF_INET;

      *real_host = strdup (ns->ip4_hostent->h_name);
      return strdup (inet_ntoa (ns->addr.sin_addr));
}

int
net_connect (netstore * ns, int sok4, int sok6, int *sok_return)
{
      *sok_return = sok4;
      return connect (sok4, (struct sockaddr *) &ns->addr, sizeof (ns->addr));
}

void
net_bind (netstore * tobindto, int sok4, int sok6)
{
      bind (sok4, (struct sockaddr *) &tobindto->addr, sizeof (tobindto->addr));
}

void
net_sockets (int *sok4, int *sok6)
{
      *sok4 = socket (AF_INET, SOCK_STREAM, 0);
      *sok6 = -1;
      net_set_socket_options (*sok4);
}

#else

/* =================== IPV6 ================== */

char *
net_resolve (netstore * ns, char *hostname, int port, char **real_host)
{
      struct addrinfo hints;
      char ipstring[MAX_HOSTNAME];
      char portstring[MAX_HOSTNAME];
      int ret;

/*    if (ns->ip6_hostent)
            freeaddrinfo (ns->ip6_hostent);*/

      sprintf (portstring, "%d", port);

      memset (&hints, 0, sizeof (struct addrinfo));
      hints.ai_family = PF_UNSPEC; /* support ipv6 and ipv4 */
      hints.ai_flags = AI_CANONNAME;
      hints.ai_socktype = SOCK_STREAM;

      if (port == 0)
            ret = getaddrinfo (hostname, NULL, &hints, &ns->ip6_hostent);
      else
            ret = getaddrinfo (hostname, portstring, &hints, &ns->ip6_hostent);
      if (ret != 0)
            return NULL;

#ifdef LOOKUPD    /* See note about lookupd above the IPv4 version of net_resolve. */
      struct addrinfo *tmp;
      int count = 0;

      for (tmp = ns->ip6_hostent; tmp; tmp = tmp->ai_next)
            count ++;

      count = RAND_INT(count);
      
      while (count--) ns->ip6_hostent = ns->ip6_hostent->ai_next;
#endif

      /* find the numeric IP number */
      ipstring[0] = 0;
      getnameinfo (ns->ip6_hostent->ai_addr, ns->ip6_hostent->ai_addrlen,
                               ipstring, sizeof (ipstring), NULL, 0, NI_NUMERICHOST);

      if (ns->ip6_hostent->ai_canonname)
            *real_host = strdup (ns->ip6_hostent->ai_canonname);
      else
            *real_host = strdup (hostname);

      return strdup (ipstring);
}

/* the only thing making this interface unclean, this shitty sok4, sok6 business */

int
net_connect (netstore * ns, int sok4, int sok6, int *sok_return)
{
      struct addrinfo *res, *res0;
      int error = -1;

      res0 = ns->ip6_hostent;

      for (res = res0; res; res = res->ai_next)
      {
/*          sok = socket (res->ai_family, res->ai_socktype, res->ai_protocol);
            if (sok < 0)
                  continue;*/
            switch (res->ai_family)
            {
            case AF_INET:
                  error = connect (sok4, res->ai_addr, res->ai_addrlen);
                  *sok_return = sok4;
                  break;
            case AF_INET6:
                  error = connect (sok6, res->ai_addr, res->ai_addrlen);
                  *sok_return = sok6;
                  break;
            default:
                  error = 1;
            }

            if (error == 0)
                  break;
      }

      return error;
}

void
net_bind (netstore * tobindto, int sok4, int sok6)
{
      bind (sok4, tobindto->ip6_hostent->ai_addr,
                  tobindto->ip6_hostent->ai_addrlen);
      bind (sok6, tobindto->ip6_hostent->ai_addr,
                  tobindto->ip6_hostent->ai_addrlen);
}

void
net_sockets (int *sok4, int *sok6)
{
      *sok4 = socket (AF_INET, SOCK_STREAM, IPPROTO_TCP);
      *sok6 = socket (AF_INET6, SOCK_STREAM, IPPROTO_TCP);
      net_set_socket_options (*sok4);
      net_set_socket_options (*sok6);
}

#endif

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