tinc/src/subnet.c

/*
    subnet.c -- handle subnet lookups and lists
    Copyright (C) 2000-2002 Guus Sliepen <guus@sliepen.warande.net>,
                  2000-2002 Ivo Timmermans <itimmermans@bigfoot.com>

    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: subnet.c,v 1.1.2.29 2002/02/10 21:57:54 guus Exp $
*/

#include "config.h"

#include <stdio.h>
#include <syslog.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <netinet/in.h>

#include "conf.h"
#include "net.h"
#include "node.h"
#include "subnet.h"
#include "system.h"

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

/* lists type of subnet */

avl_tree_t *subnet_tree;

/* Subnet comparison */

int subnet_compare_mac(subnet_t *a, subnet_t *b)
{
cp
  return memcmp(&a->net.mac.address, &b->net.mac.address, sizeof(mac_t));
}

int subnet_compare_ipv4(subnet_t *a, subnet_t *b)
{
cp
  /* We compare as if a subnet is a number that equals (address << 32 + netmask). */
   
  if(a->net.ipv4.address < b->net.ipv4.address)
    return -1;
  else if(a->net.ipv4.address > b->net.ipv4.address)
    return 1;

  if(a->net.ipv4.mask < b->net.ipv4.mask)
    return -1;
  else if(a->net.ipv4.mask > b->net.ipv4.mask)
    return 1;

  return 0;
}

int subnet_compare_ipv6(subnet_t *a, subnet_t *b)
{
  int result;
cp
  /* Same as ipv4 case, but with nasty 128 bit addresses */
  
  result = memcmp(a->net.ipv6.address.x, b->net.ipv6.address.x, sizeof(ipv6_t));
  
  if(result)
    return result;

  result = memcmp(a->net.ipv6.mask.x, b->net.ipv6.mask.x, sizeof(ipv6_t));
  
  if(result)
    return result;

  return 0;
}

int subnet_compare(subnet_t *a, subnet_t *b)
{
  int x;
cp  
  x = a->type - b->type;
  if(x)
    return x;
    
  switch(a->type)
    {
      case SUBNET_MAC:
        return subnet_compare_mac(a, b);
      case SUBNET_IPV4:
        return subnet_compare_ipv4(a, b);
      case SUBNET_IPV6:
        return subnet_compare_ipv6(a, b);
      default:
        syslog(LOG_ERR, _("subnet_compare() was called with unknown subnet type %d, exitting!"), a->type);
        cp_trace();
        exit(0);
    }

  return 0;
}

/* Initialising trees */

void init_subnets(void)
{
cp
  subnet_tree = avl_alloc_tree((avl_compare_t)subnet_compare, (avl_action_t)free_subnet);
cp
}

void exit_subnets(void)
{
cp
  avl_delete_tree(subnet_tree);
cp
}

avl_tree_t *new_subnet_tree(void)
{
cp
  return avl_alloc_tree((avl_compare_t)subnet_compare, NULL);
cp
}

void free_subnet_tree(avl_tree_t *subnet_tree)
{
cp
  avl_delete_tree(subnet_tree);
cp
}

/* Allocating and freeing space for subnets */

subnet_t *new_subnet(void)
{
cp
  return (subnet_t *)xmalloc(sizeof(subnet_t));
}

void free_subnet(subnet_t *subnet)
{
cp
  free(subnet);
}

/* Adding and removing subnets */

void subnet_add(node_t *n, subnet_t *subnet)
{
cp
  subnet->owner = n;

  avl_insert(subnet_tree, subnet);
cp
  avl_insert(n->subnet_tree, subnet);
cp
}

void subnet_del(node_t *n, subnet_t *subnet)
{
cp
  avl_delete(n->subnet_tree, subnet);
cp
  avl_delete(subnet_tree, subnet);
cp
}

/* Ascii representation of subnets */

subnet_t *str2net(char *subnetstr)
{
  int i, l;
  subnet_t *subnet;
  unsigned short int x[6];
cp
  subnet = new_subnet();
cp
  if(sscanf(subnetstr, "%hu.%hu.%hu.%hu/%d",
              &x[0],
              &x[1],
              &x[2],
              &x[3],
              &subnet->net.ipv4.masklength) == 5)
    {
      subnet->type = SUBNET_IPV4;
      subnet->net.ipv4.address = (((((x[0] << 8) + x[1]) << 8) + x[2]) << 8) + x[3];
      subnet->net.ipv4.mask = ~((1 << (32 - subnet->net.ipv4.masklength)) - 1);
      return subnet;
    }
	      
  if(sscanf(subnetstr, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx/%d",
             &subnet->net.ipv6.address.x[0],
             &subnet->net.ipv6.address.x[1],
             &subnet->net.ipv6.address.x[2],
             &subnet->net.ipv6.address.x[3],
             &subnet->net.ipv6.address.x[4],
             &subnet->net.ipv6.address.x[5],
             &subnet->net.ipv6.address.x[6],
             &subnet->net.ipv6.address.x[7],
             &subnet->net.ipv6.masklength) == 9)
    {
      subnet->type = SUBNET_IPV6;
      for(l = subnet->net.ipv6.masklength, i = 0; i < 8; l -= 16, i++)
      {
        subnet->net.ipv6.address.x[i] = htons(subnet->net.ipv6.address.x[i]);
        if(l >= 16)
          subnet->net.ipv6.mask.x[i] = 65535;
	else if (l > 0)
	  subnet->net.ipv6.mask.x[i] = htons(65536 - (1 << l));
	else
          subnet->net.ipv6.mask.x[i] = 0;
      }
      return subnet;
    }

  if(sscanf(subnetstr, "%hu.%hu.%hu.%hu",
              &x[0],
              &x[1],
              &x[2],
              &x[3]) == 4)
    {
      subnet->type = SUBNET_IPV4;
      subnet->net.ipv4.address = (((((x[0] << 8) + x[1]) << 8) + x[2]) << 8) + x[3];
      subnet->net.ipv4.mask = ~0;
      subnet->net.ipv4.masklength = 32;
      return subnet;
    }
	      
  if(sscanf(subnetstr, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx",
             &subnet->net.ipv6.address.x[0],
             &subnet->net.ipv6.address.x[1],
             &subnet->net.ipv6.address.x[2],
             &subnet->net.ipv6.address.x[3],
             &subnet->net.ipv6.address.x[4],
             &subnet->net.ipv6.address.x[5],
             &subnet->net.ipv6.address.x[6],
             &subnet->net.ipv6.address.x[7]) == 8)
    {
      subnet->type = SUBNET_IPV6;
      subnet->net.ipv6.masklength = 128;
      for(l = subnet->net.ipv6.masklength, i = 0; i < 8; l -= 16, i++)
      {
        subnet->net.ipv6.address.x[i] = htons(subnet->net.ipv6.address.x[i]);
        if(l >= 16)
          subnet->net.ipv6.mask.x[i] = 65535;
	else if (l > 0)
	  subnet->net.ipv6.mask.x[i] = htons(65536 - (1 << l));
	else
          subnet->net.ipv6.mask.x[i] = 0;
      }
      return subnet;
    }

  if(sscanf(subnetstr, "%hx:%hx:%hx:%hx:%hx:%hx",
              &x[0],
              &x[1],
              &x[2],
              &x[3],
              &x[4],
              &x[5]) == 6)
    {
      subnet->type = SUBNET_MAC;
      subnet->net.mac.address.x[0] = x[0];
      subnet->net.mac.address.x[1] = x[1];
      subnet->net.mac.address.x[2] = x[2];
      subnet->net.mac.address.x[3] = x[3];
      subnet->net.mac.address.x[4] = x[4];
      subnet->net.mac.address.x[5] = x[5];
      return subnet;
    }

  free(subnet);
  return NULL;
}

char *net2str(subnet_t *subnet)
{
  char *netstr;
cp
  switch(subnet->type)
    {
      case SUBNET_MAC:
        asprintf(&netstr, "%hx:%hx:%hx:%hx:%hx:%hx",
                   subnet->net.mac.address.x[0],
                   subnet->net.mac.address.x[1],
                   subnet->net.mac.address.x[2],
                   subnet->net.mac.address.x[3],
                   subnet->net.mac.address.x[4],
                   subnet->net.mac.address.x[5]);
        break;
      case SUBNET_IPV4:
        asprintf(&netstr, "%hu.%hu.%hu.%hu/%d",
	           (unsigned short int)((subnet->net.ipv4.address >> 24) & 255),
	           (unsigned short int)((subnet->net.ipv4.address >> 16) & 255),
	           (unsigned short int)((subnet->net.ipv4.address >> 8) & 255),
	           (unsigned short int)(subnet->net.ipv4.address & 255),
		   subnet->net.ipv4.masklength);
        break;
      case SUBNET_IPV6:
        asprintf(&netstr, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx/%d",
                   ntohs(subnet->net.ipv6.address.x[0]),
                   ntohs(subnet->net.ipv6.address.x[1]),
                   ntohs(subnet->net.ipv6.address.x[2]),
                   ntohs(subnet->net.ipv6.address.x[3]),
                   ntohs(subnet->net.ipv6.address.x[4]),
                   ntohs(subnet->net.ipv6.address.x[5]),
                   ntohs(subnet->net.ipv6.address.x[6]),
                   ntohs(subnet->net.ipv6.address.x[7]),
                   subnet->net.ipv6.masklength);
        break;
      default:
        asprintf(&netstr, _("unknown subnet type"));
    }
cp
  return netstr;
}

/* Subnet lookup routines */

subnet_t *lookup_subnet(node_t *owner, subnet_t *subnet)
{
cp  
  return avl_search(owner->subnet_tree, subnet);
}

subnet_t *lookup_subnet_mac(mac_t *address)
{
  subnet_t subnet, *p;
cp
  subnet.type = SUBNET_MAC;
  memcpy(&subnet.net.mac.address, address, sizeof(mac_t));

  p = (subnet_t *)avl_search(subnet_tree, &subnet);
cp
  return p;
}

subnet_t *lookup_subnet_ipv4(ipv4_t *address)
{
  subnet_t subnet, *p;
cp
  subnet.type = SUBNET_IPV4;
  subnet.net.ipv4.address = *address;
  subnet.net.ipv4.mask = 0xFFFFFFFF;

  do
  {
    /* Go find subnet */
  
    p = (subnet_t *)avl_search_closest_smaller(subnet_tree, &subnet);

  /* Check if the found subnet REALLY matches */
cp
    if(p)
      {
        if ((*address & p->net.ipv4.mask) == p->net.ipv4.address)
          break;
        else
          {
            /* Otherwise, see if there is a bigger enclosing subnet */

            subnet.net.ipv4.mask = p->net.ipv4.mask << 1;
            subnet.net.ipv4.address = p->net.ipv4.address & subnet.net.ipv4.mask;
          }
      }
   } while (p);
   
   return p;
}

subnet_t *lookup_subnet_ipv6(ipv6_t *address)
{
  subnet_t subnet, *p;
  int i;
cp
  subnet.type = SUBNET_IPV6;
  memcpy(subnet.net.ipv6.address.x, address, sizeof(ipv6_t));
  memset(subnet.net.ipv6.mask.x, 0xFF, 16);
  
  p = (subnet_t *)avl_search_closest_greater(subnet_tree, &subnet);
  
  if(p)
    for(i=0; i<8; i++)
      if((address->x[i] & p->net.ipv6.address.x[i]) != p->net.ipv6.address.x[i])
        return NULL;

  return p;
}

void dump_subnets(void)
{
  char *netstr;
  subnet_t *subnet;
  avl_node_t *node;
cp
  syslog(LOG_DEBUG, _("Subnet list:"));
  for(node = subnet_tree->head; node; node = node->next)
    {
      subnet = (subnet_t *)node->data;
      netstr = net2str(subnet);
      syslog(LOG_DEBUG, _(" %s owner %s"), netstr, subnet->owner->name);
      free(netstr);
    }
  syslog(LOG_DEBUG, _("End of subnet list."));
cp
}