1 /* Kernel module to match the bridge port in and
2 * out device for IP packets coming into contact with a bridge. */
4 /* (C) 2001-2003 Bart De Schuymer <bdschuym@pandora.be>
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.
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>
17 MODULE_LICENSE("GPL");
18 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
19 MODULE_DESCRIPTION("Xtables: Bridge physical device match");
20 MODULE_ALIAS("ipt_physdev");
21 MODULE_ALIAS("ip6t_physdev");
23 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
25 const unsigned long *a = (const unsigned long *)_a;
26 const unsigned long *b = (const unsigned long *)_b;
27 const unsigned long *mask = (const unsigned long *)_mask;
30 ret = (a[0] ^ b[0]) & mask[0];
31 if (IFNAMSIZ > sizeof(unsigned long))
32 ret |= (a[1] ^ b[1]) & mask[1];
33 if (IFNAMSIZ > 2 * sizeof(unsigned long))
34 ret |= (a[2] ^ b[2]) & mask[2];
35 if (IFNAMSIZ > 3 * sizeof(unsigned long))
36 ret |= (a[3] ^ b[3]) & mask[3];
37 BUILD_BUG_ON(IFNAMSIZ > 4 * sizeof(unsigned long));
42 physdev_mt(const struct sk_buff *skb, const struct xt_match_param *par)
44 static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
45 const struct xt_physdev_info *info = par->matchinfo;
47 const char *indev, *outdev;
48 const struct nf_bridge_info *nf_bridge;
50 /* Not a bridged IP packet or no info available yet:
51 * LOCAL_OUT/mangle and LOCAL_OUT/nat don't know if
52 * the destination device will be a bridge. */
53 if (!(nf_bridge = skb->nf_bridge)) {
54 /* Return MATCH if the invert flags of the used options are on */
55 if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
56 !(info->invert & XT_PHYSDEV_OP_BRIDGED))
58 if ((info->bitmask & XT_PHYSDEV_OP_ISIN) &&
59 !(info->invert & XT_PHYSDEV_OP_ISIN))
61 if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) &&
62 !(info->invert & XT_PHYSDEV_OP_ISOUT))
64 if ((info->bitmask & XT_PHYSDEV_OP_IN) &&
65 !(info->invert & XT_PHYSDEV_OP_IN))
67 if ((info->bitmask & XT_PHYSDEV_OP_OUT) &&
68 !(info->invert & XT_PHYSDEV_OP_OUT))
73 /* This only makes sense in the FORWARD and POSTROUTING chains */
74 if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
75 (!!(nf_bridge->mask & BRNF_BRIDGED) ^
76 !(info->invert & XT_PHYSDEV_OP_BRIDGED)))
79 if ((info->bitmask & XT_PHYSDEV_OP_ISIN &&
80 (!nf_bridge->physindev ^ !!(info->invert & XT_PHYSDEV_OP_ISIN))) ||
81 (info->bitmask & XT_PHYSDEV_OP_ISOUT &&
82 (!nf_bridge->physoutdev ^ !!(info->invert & XT_PHYSDEV_OP_ISOUT))))
85 if (!(info->bitmask & XT_PHYSDEV_OP_IN))
87 indev = nf_bridge->physindev ? nf_bridge->physindev->name : nulldevname;
88 ret = ifname_compare(indev, info->physindev, info->in_mask);
90 if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN))
94 if (!(info->bitmask & XT_PHYSDEV_OP_OUT))
96 outdev = nf_bridge->physoutdev ?
97 nf_bridge->physoutdev->name : nulldevname;
98 ret = ifname_compare(outdev, info->physoutdev, info->out_mask);
100 return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT));
103 static bool physdev_mt_check(const struct xt_mtchk_param *par)
105 const struct xt_physdev_info *info = par->matchinfo;
107 if (!(info->bitmask & XT_PHYSDEV_OP_MASK) ||
108 info->bitmask & ~XT_PHYSDEV_OP_MASK)
110 if (info->bitmask & XT_PHYSDEV_OP_OUT &&
111 (!(info->bitmask & XT_PHYSDEV_OP_BRIDGED) ||
112 info->invert & XT_PHYSDEV_OP_BRIDGED) &&
113 par->hook_mask & ((1 << NF_INET_LOCAL_OUT) |
114 (1 << NF_INET_FORWARD) | (1 << NF_INET_POST_ROUTING))) {
115 printk(KERN_WARNING "physdev match: using --physdev-out in the "
116 "OUTPUT, FORWARD and POSTROUTING chains for non-bridged "
117 "traffic is not supported anymore.\n");
118 if (par->hook_mask & (1 << NF_INET_LOCAL_OUT))
124 static struct xt_match physdev_mt_reg __read_mostly = {
127 .family = NFPROTO_UNSPEC,
128 .checkentry = physdev_mt_check,
130 .matchsize = sizeof(struct xt_physdev_info),
134 static int __init physdev_mt_init(void)
136 return xt_register_match(&physdev_mt_reg);
139 static void __exit physdev_mt_exit(void)
141 xt_unregister_match(&physdev_mt_reg);
144 module_init(physdev_mt_init);
145 module_exit(physdev_mt_exit);