release/src-rt-6.x/linux/linux-2.6/net/netfilter/xt_physdev.c

   1 /* Kernel module to match the bridge port in and
   2  * out device for IP packets coming into contact with a bridge. */
   3
   4 /* (C) 2001-2003 Bart De Schuymer <bdschuym@pandora.be>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/netfilter_bridge.h>
  14 #include <linux/netfilter/xt_physdev.h>
  15 #include <linux/netfilter/x_tables.h>
  16 #include <linux/netfilter_bridge.h>
  17 #define MATCH   1
  18 #define NOMATCH 0
  19
  20 MODULE_LICENSE("GPL");
  21 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
  22 MODULE_DESCRIPTION("iptables bridge physical device match module");
  23 MODULE_ALIAS("ipt_physdev");
  24 MODULE_ALIAS("ip6t_physdev");
  25
  26
  27 static int
  28 match(const struct sk_buff *skb,
  29       const struct net_device *in,
  30       const struct net_device *out,
  31       const struct xt_match *match,
  32       const void *matchinfo,
  33       int offset,
  34       unsigned int protoff,
  35       int *hotdrop)
  36 {
  37         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
  38         const struct xt_physdev_info *info = matchinfo;
  39         unsigned long ret;
  40         const char *indev, *outdev;
  41         struct nf_bridge_info *nf_bridge;
  42
  43         /* Not a bridged IP packet or no info available yet:
  44          * LOCAL_OUT/mangle and LOCAL_OUT/nat don't know if
  45          * the destination device will be a bridge. */
  46         if (!(nf_bridge = skb->nf_bridge)) {
  47                 /* Return MATCH if the invert flags of the used options are on */
  48                 if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
  49                     !(info->invert & XT_PHYSDEV_OP_BRIDGED))
  50                         return NOMATCH;
  51                 if ((info->bitmask & XT_PHYSDEV_OP_ISIN) &&
  52                     !(info->invert & XT_PHYSDEV_OP_ISIN))
  53                         return NOMATCH;
  54                 if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) &&
  55                     !(info->invert & XT_PHYSDEV_OP_ISOUT))
  56                         return NOMATCH;
  57                 if ((info->bitmask & XT_PHYSDEV_OP_IN) &&
  58                     !(info->invert & XT_PHYSDEV_OP_IN))
  59                         return NOMATCH;
  60                 if ((info->bitmask & XT_PHYSDEV_OP_OUT) &&
  61                     !(info->invert & XT_PHYSDEV_OP_OUT))
  62                         return NOMATCH;
  63                 return MATCH;
  64         }
  65
  66         /* This only makes sense in the FORWARD and POSTROUTING chains */
  67         if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
  68             (!!(nf_bridge->mask & BRNF_BRIDGED) ^
  69             !(info->invert & XT_PHYSDEV_OP_BRIDGED)))
  70                 return NOMATCH;
  71
  72         if ((info->bitmask & XT_PHYSDEV_OP_ISIN &&
  73             (!nf_bridge->physindev ^ !!(info->invert & XT_PHYSDEV_OP_ISIN))) ||
  74             (info->bitmask & XT_PHYSDEV_OP_ISOUT &&
  75             (!nf_bridge->physoutdev ^ !!(info->invert & XT_PHYSDEV_OP_ISOUT))))
  76                 return NOMATCH;
  77
  78         if (!(info->bitmask & XT_PHYSDEV_OP_IN))
  79                 goto match_outdev;
  80         indev = nf_bridge->physindev ? nf_bridge->physindev->name : nulldevname;
  81         ret = ifname_compare_aligned(indev, info->physindev, info->in_mask);
  82
  83         if ((ret == 0) ^ !(info->invert & XT_PHYSDEV_OP_IN))
  84                 return NOMATCH;
  85
  86 match_outdev:
  87         if (!(info->bitmask & XT_PHYSDEV_OP_OUT))
  88                 return MATCH;
  89         outdev = nf_bridge->physoutdev ?
  90                  nf_bridge->physoutdev->name : nulldevname;
  91         ret = ifname_compare_aligned(outdev, info->physoutdev, info->out_mask);
  92
  93         return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT));
  94 }
  95
  96 static int
  97 checkentry(const char *tablename,
  98                        const void *ip,
  99                        const struct xt_match *match,
 100                        void *matchinfo,
 101                        unsigned int hook_mask)
 102 {
 103         const struct xt_physdev_info *info = matchinfo;
 104
 105         if (!(info->bitmask & XT_PHYSDEV_OP_MASK) ||
 106             info->bitmask & ~XT_PHYSDEV_OP_MASK)
 107                 return 0;
 108         if (info->bitmask & XT_PHYSDEV_OP_OUT &&
 109             (!(info->bitmask & XT_PHYSDEV_OP_BRIDGED) ||
 110              info->invert & XT_PHYSDEV_OP_BRIDGED) &&
 111             hook_mask & ((1 << NF_IP_LOCAL_OUT) | (1 << NF_IP_FORWARD) |
 112                          (1 << NF_IP_POST_ROUTING))) {
 113                 printk(KERN_WARNING "physdev match: using --physdev-out in the "
 114                        "OUTPUT, FORWARD and POSTROUTING chains for non-bridged "
 115                        "traffic is not supported anymore.\n");
 116                 if (hook_mask & (1 << NF_IP_LOCAL_OUT))
 117                         return 0;
 118         }
 119         return 1;
 120 }
 121
 122 static struct xt_match xt_physdev_match[] = {
 123         {
 124                 .name           = "physdev",
 125                 .family         = AF_INET,
 126                 .checkentry     = checkentry,
 127                 .match          = match,
 128                 .matchsize      = sizeof(struct xt_physdev_info),
 129                 .me             = THIS_MODULE,
 130         },
 131         {
 132                 .name           = "physdev",
 133                 .family         = AF_INET6,
 134                 .checkentry     = checkentry,
 135                 .match          = match,
 136                 .matchsize      = sizeof(struct xt_physdev_info),
 137                 .me             = THIS_MODULE,
 138         },
 139 };
 140
 141 static int __init xt_physdev_init(void)
 142 {
 143         return xt_register_matches(xt_physdev_match,
 144                                    ARRAY_SIZE(xt_physdev_match));
 145 }
 146
 147 static void __exit xt_physdev_fini(void)
 148 {
 149         xt_unregister_matches(xt_physdev_match, ARRAY_SIZE(xt_physdev_match));
 150 }
 151
 152 module_init(xt_physdev_init);
 153 module_exit(xt_physdev_fini);