1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Kernel module to match the bridge port in and
3 * out device for IP packets coming into contact with a bridge. */
5 /* (C) 2001-2003 Bart De Schuymer <bdschuym@pandora.be>
7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8 #include <linux/module.h>
9 #include <linux/skbuff.h>
10 #include <linux/netfilter_bridge.h>
11 #include <linux/netfilter/xt_physdev.h>
12 #include <linux/netfilter/x_tables.h>
13 #include <net/netfilter/br_netfilter.h>
15 MODULE_LICENSE("GPL");
16 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
17 MODULE_DESCRIPTION("Xtables: Bridge physical device match");
18 MODULE_ALIAS("ipt_physdev");
19 MODULE_ALIAS("ip6t_physdev");
23 physdev_mt(const struct sk_buff *skb, struct xt_action_param *par)
25 const struct xt_physdev_info *info = par->matchinfo;
26 const struct net_device *physdev;
28 const char *indev, *outdev;
30 /* Not a bridged IP packet or no info available yet:
31 * LOCAL_OUT/mangle and LOCAL_OUT/nat don't know if
32 * the destination device will be a bridge. */
33 if (!nf_bridge_info_exists(skb)) {
34 /* Return MATCH if the invert flags of the used options are on */
35 if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
36 !(info->invert & XT_PHYSDEV_OP_BRIDGED))
38 if ((info->bitmask & XT_PHYSDEV_OP_ISIN) &&
39 !(info->invert & XT_PHYSDEV_OP_ISIN))
41 if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) &&
42 !(info->invert & XT_PHYSDEV_OP_ISOUT))
44 if ((info->bitmask & XT_PHYSDEV_OP_IN) &&
45 !(info->invert & XT_PHYSDEV_OP_IN))
47 if ((info->bitmask & XT_PHYSDEV_OP_OUT) &&
48 !(info->invert & XT_PHYSDEV_OP_OUT))
53 physdev = nf_bridge_get_physoutdev(skb);
54 outdev = physdev ? physdev->name : NULL;
56 /* This only makes sense in the FORWARD and POSTROUTING chains */
57 if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
58 (!!outdev ^ !(info->invert & XT_PHYSDEV_OP_BRIDGED)))
61 physdev = nf_bridge_get_physindev(skb);
62 indev = physdev ? physdev->name : NULL;
64 if ((info->bitmask & XT_PHYSDEV_OP_ISIN &&
65 (!indev ^ !!(info->invert & XT_PHYSDEV_OP_ISIN))) ||
66 (info->bitmask & XT_PHYSDEV_OP_ISOUT &&
67 (!outdev ^ !!(info->invert & XT_PHYSDEV_OP_ISOUT))))
70 if (!(info->bitmask & XT_PHYSDEV_OP_IN))
74 ret = ifname_compare_aligned(indev, info->physindev,
77 if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN))
82 if (!(info->bitmask & XT_PHYSDEV_OP_OUT))
88 ret = ifname_compare_aligned(outdev, info->physoutdev, info->out_mask);
90 return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT));
93 static int physdev_mt_check(const struct xt_mtchk_param *par)
95 const struct xt_physdev_info *info = par->matchinfo;
96 static bool brnf_probed __read_mostly;
98 if (!(info->bitmask & XT_PHYSDEV_OP_MASK) ||
99 info->bitmask & ~XT_PHYSDEV_OP_MASK)
101 if (info->bitmask & (XT_PHYSDEV_OP_OUT | XT_PHYSDEV_OP_ISOUT) &&
102 (!(info->bitmask & XT_PHYSDEV_OP_BRIDGED) ||
103 info->invert & XT_PHYSDEV_OP_BRIDGED) &&
104 par->hook_mask & (1 << NF_INET_LOCAL_OUT)) {
105 pr_info_ratelimited("--physdev-out and --physdev-is-out only supported in the FORWARD and POSTROUTING chains with bridged traffic\n");
111 request_module("br_netfilter");
117 static struct xt_match physdev_mt_reg __read_mostly = {
120 .family = NFPROTO_UNSPEC,
121 .checkentry = physdev_mt_check,
123 .matchsize = sizeof(struct xt_physdev_info),
127 static int __init physdev_mt_init(void)
129 return xt_register_match(&physdev_mt_reg);
132 static void __exit physdev_mt_exit(void)
134 xt_unregister_match(&physdev_mt_reg);
137 module_init(physdev_mt_init);
138 module_exit(physdev_mt_exit);