release/src/router/dnsmasq/src/conntrack.c

   1 /* dnsmasq is Copyright (c) 2000-2013 Simon Kelley
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 dated June, 1991, or
   6    (at your option) version 3 dated 29 June, 2007.
   7
   8    This program is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11    GNU General Public License for more details.
  12
  13    You should have received a copy of the GNU General Public License
  14    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15 */
  16
  17 #include "dnsmasq.h"
  18
  19 #ifdef HAVE_CONNTRACK
  20
  21 #include <libnetfilter_conntrack/libnetfilter_conntrack.h>
  22
  23 static int gotit = 0; /* yuck */
  24
  25 static int callback(enum nf_conntrack_msg_type type, struct nf_conntrack *ct, void *data);
  26
  27 int get_incoming_mark(union mysockaddr *peer_addr, struct all_addr *local_addr, int istcp, unsigned int *markp)
  28 {
  29   struct nf_conntrack *ct;
  30   struct nfct_handle *h;
  31
  32   gotit = 0;
  33
  34   if ((ct = nfct_new()))
  35     {
  36       nfct_set_attr_u8(ct, ATTR_L4PROTO, istcp ? IPPROTO_TCP : IPPROTO_UDP);
  37       nfct_set_attr_u16(ct, ATTR_PORT_DST, htons(daemon->port));
  38
  39 #ifdef HAVE_IPV6
  40       if (peer_addr->sa.sa_family == AF_INET6)
  41         {
  42           nfct_set_attr_u8(ct, ATTR_L3PROTO, AF_INET6);
  43           nfct_set_attr(ct, ATTR_IPV6_SRC, peer_addr->in6.sin6_addr.s6_addr);
  44           nfct_set_attr_u16(ct, ATTR_PORT_SRC, peer_addr->in6.sin6_port);
  45           nfct_set_attr(ct, ATTR_IPV6_DST, local_addr->addr.addr6.s6_addr);
  46         }
  47       else
  48 #endif
  49         {
  50           nfct_set_attr_u8(ct, ATTR_L3PROTO, AF_INET);
  51           nfct_set_attr_u32(ct, ATTR_IPV4_SRC, peer_addr->in.sin_addr.s_addr);
  52           nfct_set_attr_u16(ct, ATTR_PORT_SRC, peer_addr->in.sin_port);
  53           nfct_set_attr_u32(ct, ATTR_IPV4_DST, local_addr->addr.addr4.s_addr);
  54         }
  55
  56
  57       if ((h = nfct_open(CONNTRACK, 0)))
  58         {
  59           nfct_callback_register(h, NFCT_T_ALL, callback, (void *)markp);
  60           if (nfct_query(h, NFCT_Q_GET, ct) == -1)
  61             {
  62               static int warned = 0;
  63               if (!warned)
  64                 {
  65                   my_syslog(LOG_ERR, _("Conntrack connection mark retrieval failed: %s"), strerror(errno));
  66                   warned = 1;
  67                 }
  68             }
  69           nfct_close(h);
  70         }
  71       nfct_destroy(ct);
  72     }
  73
  74   return gotit;
  75 }
  76
  77 static int callback(enum nf_conntrack_msg_type type, struct nf_conntrack *ct, void *data)
  78 {
  79   unsigned int *ret = (unsigned int *)data;
  80   *ret = nfct_get_attr_u32(ct, ATTR_MARK);
  81   (void)type; /* eliminate warning */
  82   gotit = 1;
  83
  84   return NFCT_CB_CONTINUE;
  85 }
  86
  87 #endif
  88
  89
  90