server/src/ndp.c

   1 /*
   2  *  tunnel6
   3  *  Copyright (C) 2010  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   4  *
   5  *  This program is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include "db.h"
  23 #include "ndp.h"
  24 #include "ipv6.h"
  25 #include "sniff.h"
  26 #include "packet.h"
  27 #include "checksum.h"
  28
  29 extern struct netdev_t netdev;
  30
  31 /* send neighbour advertisement - we lie about existing address  :-B */
  32 int ndp_reply (struct proto_eth_t *eth, char *data)
  33 {
  34         struct proto_ipv6_t *ip = (struct proto_ipv6_t *) data;
  35         struct proto_ndp_t *ndp = (struct proto_ndp_t *) ((char *) data + sizeof (struct proto_ipv6_t));
  36
  37         /* check for neighbour solicitation packet */
  38         if (ndp->type != NDP_TYPE_NBSOL)
  39                 return -1;
  40
  41         /* check target with database */
  42         client_t *c = db_check (ndp->target);
  43
  44         if (!c)
  45                 return 0;
  46
  47         if (!c->info)
  48                 return 0;
  49
  50         /* build a new packet */
  51         char packet[sizeof (struct proto_eth_t) + sizeof (struct proto_ipv6_t) + sizeof (struct proto_ndp_t) + 1];
  52
  53         /* ethernet layer */
  54         struct proto_eth_t *packet_eth = (struct proto_eth_t *) &packet;
  55
  56         memcpy (&packet_eth->src, netdev.hwaddr, sizeof (mac_addr_t));
  57         memcpy (&packet_eth->dest, eth->src, sizeof (mac_addr_t));
  58         packet_eth->type = PACKET_TYPE_IPV6;
  59
  60         /* IPv6 layer */
  61         struct proto_ipv6_t *packet_ip = (struct proto_ipv6_t *) ((char *) &packet + sizeof (struct proto_eth_t));
  62
  63         packet_ip->ver = 0x60;
  64         packet_ip->tclass = 0x0;
  65         packet_ip->flabel = 0x0;
  66         packet_ip->pl_len = htons (32);
  67         packet_ip->nhead = IPV6_TYPE_ICMPv6;
  68         packet_ip->hop = 0xff;
  69         memcpy (packet_ip->src, (void *) ndp->target, sizeof (ipv6_addr_t));
  70         memcpy (packet_ip->dest, (void *) ip->src, sizeof (ipv6_addr_t));
  71
  72         /* ICMPv6 - NDP layer */
  73         struct proto_ndp_t *packet_ndp = (struct proto_ndp_t *) ((char *) &packet + sizeof (struct proto_eth_t) + sizeof (struct proto_ipv6_t));
  74
  75         packet_ndp->type = NDP_TYPE_NBADV;
  76         packet_ndp->code = 0;
  77         packet_ndp->flags = htonl (0x60000000);
  78         memcpy (packet_ndp->target, (void *) ndp->target, sizeof (ipv6_addr_t));
  79
  80         packet_ndp->ll_type = 2;
  81         packet_ndp->ll_length = 1;
  82         memcpy (&packet_ndp->ll_mac, netdev.hwaddr, sizeof (mac_addr_t));
  83         packet_ndp->checksum = 0x0;
  84
  85         /* calculate checksum */
  86         packet_ndp->checksum = checksum16_ipv6 (packet_ip->src, packet_ip->dest, (char *) packet_ndp, sizeof (struct proto_ndp_t), IPV6_TYPE_ICMPv6);
  87
  88         /* send RAW packet */
  89         return sniff_send (packet, sizeof (struct proto_eth_t) + sizeof (struct proto_ipv6_t) + sizeof (struct proto_ndp_t));
  90 }
  91
  92 int ndp_init ()
  93 {
  94
  95         return 0;
  96 }