tinc/src/net_socket.c

/*
    net_socket.c -- Handle various kinds of sockets.
    Copyright (C) 1998-2002 Ivo Timmermans <itimmermans@bigfoot.com>,
                  2000-2002 Guus Sliepen <guus@sliepen.warande.net>

    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., 675 Mass Ave, Cambridge, MA 02139, USA.

    $Id: net_socket.c,v 1.1.2.1 2002/02/18 16:25:16 guus Exp $
*/

#include "config.h"

#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <netinet/in.h>
#ifdef HAVE_LINUX
 #include <netinet/ip.h>
 #include <netinet/tcp.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/types.h>
#include <syslog.h>
#include <unistd.h>
#include <sys/ioctl.h>
/* SunOS really wants sys/socket.h BEFORE net/if.h,
   and FreeBSD wants these lines below the rest. */
#include <arpa/inet.h>
#include <sys/socket.h>
#include <net/if.h>

#include <utils.h>
#include <xalloc.h>
#include <avl_tree.h>
#include <list.h>

#include "conf.h"
#include "connection.h"
#include "meta.h"
#include "net.h"
#include "netutl.h"
#include "process.h"
#include "protocol.h"
#include "subnet.h"
#include "graph.h"
#include "process.h"
#include "route.h"
#include "device.h"
#include "event.h"

#include "system.h"

int addressfamily = AF_INET;
int maxtimeout = 900;
int seconds_till_retry = 5;

int tcp_socket = -1;
int udp_socket = -1;
/* Setup sockets */

int setup_listen_socket(sockaddr_t *sa)
{
  int nfd, flags;
  char *addrstr;
  int option;
#ifdef HAVE_LINUX
  char *interface;
#endif
cp
  if((nfd = socket(sa->sa.sa_family, SOCK_STREAM, IPPROTO_TCP)) < 0)
    {
      syslog(LOG_ERR, _("Creating metasocket failed: %s"), strerror(errno));
      return -1;
    }

  flags = fcntl(nfd, F_GETFL);
  if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
    {
      close(nfd);
      syslog(LOG_ERR, _("System call `%s' failed: %s"), "fcntl", strerror(errno));
      return -1;
    }

  /* Optimize TCP settings */

  option = 1;
  setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
#ifdef HAVE_LINUX
  setsockopt(nfd, SOL_TCP, TCP_NODELAY, &option, sizeof(option));

  option = IPTOS_LOWDELAY;
  setsockopt(nfd, SOL_IP, IP_TOS, &option, sizeof(option));

  if(get_config_string(lookup_config(config_tree, "BindToInterface"), &interface))
    if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, interface, strlen(interface)))
      {
        close(nfd);
        syslog(LOG_ERR, _("Can't bind to interface %s: %s"), interface, strerror(errno));
        return -1;
      }
#endif

  if(bind(nfd, &sa->sa, sizeof(*sa)))
    {
      close(nfd);
      addrstr = sockaddr2hostname(sa);
      syslog(LOG_ERR, _("Can't bind to %s/tcp: %s"), addrstr, strerror(errno));
      free(addrstr);
      return -1;
    }

  if(listen(nfd, 3))
    {
      close(nfd);
      syslog(LOG_ERR, _("System call `%s' failed: %s"), "listen", strerror(errno));
      return -1;
    }
cp
  return nfd;
}

int setup_vpn_in_socket(sockaddr_t *sa)
{
  int nfd, flags;
  char *addrstr;
  int option;
#ifdef HAVE_LINUX
  char *interface;
#endif
cp
  if((nfd = socket(sa->sa.sa_family, SOCK_DGRAM, IPPROTO_UDP)) < 0)
    {
      syslog(LOG_ERR, _("Creating UDP socket failed: %s"), strerror(errno));
      return -1;
    }

  flags = fcntl(nfd, F_GETFL);
  if(fcntl(nfd, F_SETFL, flags | O_NONBLOCK) < 0)
    {
      close(nfd);
      syslog(LOG_ERR, _("System call `%s' failed: %s"), "fcntl", strerror(errno));
      return -1;
    }

  option = 1;
  setsockopt(nfd, SOL_SOCKET, SO_REUSEADDR, &option, sizeof(option));
#ifdef HAVE_LINUX
  if(get_config_string(lookup_config(config_tree, "BindToInterface"), &interface))
    if(setsockopt(nfd, SOL_SOCKET, SO_BINDTODEVICE, interface, strlen(interface)))
      {
        close(nfd);
        syslog(LOG_ERR, _("Can't bind to interface %s: %s"), interface, strerror(errno));
        return -1;
      }
#endif

  if(bind(nfd, &sa->sa, sizeof(*sa)))
    {
      close(nfd);
      addrstr = sockaddr2hostname(sa);
      syslog(LOG_ERR, _("Can't bind to %s/udp: %s"), addrstr, strerror(errno));
      free(addrstr);
      return -1;
    }
cp
  return nfd;
}

void retry_outgoing(outgoing_t *outgoing)
{
  event_t *event;
cp
  outgoing->timeout += 5;
  if(outgoing->timeout > maxtimeout)
    outgoing->timeout = maxtimeout;

  event = new_event();
  event->handler = (event_handler_t)setup_outgoing_connection;
  event->time = time(NULL) + outgoing->timeout;
  event->data = outgoing;
  event_add(event);

  if(debug_lvl >= DEBUG_CONNECTIONS)
    syslog(LOG_NOTICE, _("Trying to re-establish outgoing connection in %d seconds"), outgoing->timeout);
cp
}

int setup_outgoing_socket(connection_t *c)
{
  int option;
cp
  if(debug_lvl >= DEBUG_CONNECTIONS)
    syslog(LOG_INFO, _("Trying to connect to %s (%s)"), c->name, c->hostname);

  c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);

  if(c->socket == -1)
    {
      syslog(LOG_ERR, _("Creating socket for %s failed: %s"), c->hostname, strerror(errno));
      return -1;
    }

  /* Optimize TCP settings */

#ifdef HAVE_LINUX
  option = 1;
  setsockopt(c->socket, SOL_TCP, TCP_NODELAY, &option, sizeof(option));

  option = IPTOS_LOWDELAY;
  setsockopt(c->socket, SOL_IP, IP_TOS, &option, sizeof(option));
#endif

  /* Connect */

  if(connect(c->socket, &c->address.sa, sizeof(c->address)) == -1)
    {
      close(c->socket);
      syslog(LOG_ERR, _("%s: %s"), c->hostname, strerror(errno));
      return -1;
    }

  if(debug_lvl >= DEBUG_CONNECTIONS)
    syslog(LOG_INFO, _("Connected to %s (%s)"), c->name, c->hostname);
cp
  return 0;
}


void finish_connecting(connection_t *c)
{
cp
  if(debug_lvl >= DEBUG_CONNECTIONS)
    syslog(LOG_INFO, _("Connected to %s (%s)"), c->name, c->hostname);

  c->last_ping_time = time(NULL);

  send_id(c);
cp
}

void do_outgoing_connection(connection_t *c)
{
  char *address, *port;
  int option, result, flags;
cp
begin:
  if(!c->outgoing->ai)
    {
      if(!c->outgoing->cfg)
        {
          if(debug_lvl >= DEBUG_CONNECTIONS)
            syslog(LOG_ERR, _("Could not set up a meta connection to %s"), c->name);
          c->status.remove = 1;
	  do_prune = 1;
	  retry_outgoing(c->outgoing);
	  return;
        }

      get_config_string(c->outgoing->cfg, &address);

      if(!get_config_string(lookup_config(c->config_tree, "Port"), &port))
	asprintf(&port, "655");

      c->outgoing->ai = str2addrinfo(address, port, SOCK_STREAM);
      free(address);
      free(port);

      c->outgoing->aip = c->outgoing->ai;
      c->outgoing->cfg = lookup_config_next(c->config_tree, c->outgoing->cfg);
    }

  if(!c->outgoing->aip)
    {
      freeaddrinfo(c->outgoing->ai);
      c->outgoing->ai = NULL;
      goto begin;
    }

  memcpy(&c->address, c->outgoing->aip->ai_addr, c->outgoing->aip->ai_addrlen);
  c->outgoing->aip = c->outgoing->aip->ai_next;

  if(c->hostname)
    free(c->hostname);

  c->hostname = sockaddr2hostname(&c->address);

  if(debug_lvl >= DEBUG_CONNECTIONS)
    syslog(LOG_INFO, _("Trying to connect to %s (%s)"), c->name, c->hostname);

  c->socket = socket(c->address.sa.sa_family, SOCK_STREAM, IPPROTO_TCP);

  if(c->socket == -1)
    {
      if(debug_lvl >= DEBUG_CONNECTIONS)
        syslog(LOG_ERR, _("Creating socket for %s failed: %s"), c->hostname, strerror(errno));

      goto begin;
    }

  /* Optimize TCP settings */

#ifdef HAVE_LINUX
  option = 1;
  setsockopt(c->socket, SOL_TCP, TCP_NODELAY, &option, sizeof(option));

  option = IPTOS_LOWDELAY;
  setsockopt(c->socket, SOL_IP, IP_TOS, &option, sizeof(option));
#endif

  /* Non-blocking */

  flags = fcntl(c->socket, F_GETFL);

  if(fcntl(c->socket, F_SETFL, flags | O_NONBLOCK) < 0)
    {
      syslog(LOG_ERR, _("fcntl for %s: %s"), c->hostname, strerror(errno));
    }

  /* Connect */

  result = connect(c->socket, &c->address.sa, sizeof(c->address));

  if(result == -1)
    {
      if(errno == EINPROGRESS)
        {
          c->status.connecting = 1;
	  return;
	}

      close(c->socket);

      if(debug_lvl >= DEBUG_CONNECTIONS)
        syslog(LOG_ERR, _("%s: %s"), c->hostname, strerror(errno));

      goto begin;
    }

  finish_connecting(c);
  return;
cp
}

void setup_outgoing_connection(outgoing_t *outgoing)
{
  connection_t *c;
  node_t *n;
cp
  n = lookup_node(outgoing->name);
  
  if(n)
    if(n->connection)
      {
        if(debug_lvl >= DEBUG_CONNECTIONS)       
          syslog(LOG_INFO, _("Already connected to %s"), outgoing->name);
        n->connection->outgoing = outgoing;
        return;
      }

  c = new_connection();
  c->name = xstrdup(outgoing->name);

  init_configuration(&c->config_tree);
  read_connection_config(c);
  
  outgoing->cfg = lookup_config(c->config_tree, "Address");
  
  if(!outgoing->cfg)
    {
      syslog(LOG_ERR, _("No address specified for %s"), c->name);
      free_connection(c);
      free(outgoing->name);
      free(outgoing);
      return;
    }
  
  c->outgoing = outgoing;
  c->last_ping_time = time(NULL);

  connection_add(c);

  do_outgoing_connection(c);
}

/*
  accept a new tcp connect and create a
  new connection
*/
int handle_new_meta_connection()
{
  connection_t *c;
  sockaddr_t sa;
  int fd, len = sizeof(sa);
cp
  if((fd = accept(tcp_socket, &sa.sa, &len)) < 0)
    {
      syslog(LOG_ERR, _("Accepting a new connection failed: %s"), strerror(errno));
      return -1;
    }

  c = new_connection();

  c->address = sa;
  c->hostname = sockaddr2hostname(&sa);
  c->socket = fd;
  c->last_ping_time = time(NULL);

  if(debug_lvl >= DEBUG_CONNECTIONS)
    syslog(LOG_NOTICE, _("Connection from %s"), c->hostname);

  connection_add(c);

  c->allow_request = ID;
  send_id(c);
cp
  return 0;
}

void try_outgoing_connections(void)
{
  static config_t *cfg = NULL;
  char *name;
  outgoing_t *outgoing;
cp
  for(cfg = lookup_config(config_tree, "ConnectTo"); cfg; cfg = lookup_config_next(config_tree, cfg))
    {
      get_config_string(cfg, &name);

      if(check_id(name))
        {
          syslog(LOG_ERR, _("Invalid name for outgoing connection in %s line %d"), cfg->file, cfg->line);
          free(name);
          continue;
        }

      outgoing = xmalloc_and_zero(sizeof(*outgoing));
      outgoing->name = name;
      setup_outgoing_connection(outgoing);
    }
}