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. */ |
4 | |
5 | /* (C) 2001-2003 Bart De Schuymer <bdschuym@pandora.be> |
6 | */ |
7 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
8 | |
9 | #include <linux/if.h> |
10 | #include <linux/module.h> |
11 | #include <linux/skbuff.h> |
12 | #include <linux/netfilter_bridge.h> |
13 | #include <linux/netfilter/x_tables.h> |
14 | #include <uapi/linux/netfilter/xt_physdev.h> |
15 | |
16 | MODULE_LICENSE("GPL" ); |
17 | MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>" ); |
18 | MODULE_DESCRIPTION("Xtables: Bridge physical device match" ); |
19 | MODULE_ALIAS("ipt_physdev" ); |
20 | MODULE_ALIAS("ip6t_physdev" ); |
21 | |
22 | |
23 | static bool |
24 | physdev_mt(const struct sk_buff *skb, struct xt_action_param *par) |
25 | { |
26 | const struct xt_physdev_info *info = par->matchinfo; |
27 | const struct net_device *physdev; |
28 | unsigned long ret; |
29 | const char *indev, *outdev; |
30 | |
31 | /* Not a bridged IP packet or no info available yet: |
32 | * LOCAL_OUT/mangle and LOCAL_OUT/nat don't know if |
33 | * the destination device will be a bridge. */ |
34 | if (!nf_bridge_info_exists(skb)) { |
35 | /* Return MATCH if the invert flags of the used options are on */ |
36 | if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) && |
37 | !(info->invert & XT_PHYSDEV_OP_BRIDGED)) |
38 | return false; |
39 | if ((info->bitmask & XT_PHYSDEV_OP_ISIN) && |
40 | !(info->invert & XT_PHYSDEV_OP_ISIN)) |
41 | return false; |
42 | if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) && |
43 | !(info->invert & XT_PHYSDEV_OP_ISOUT)) |
44 | return false; |
45 | if ((info->bitmask & XT_PHYSDEV_OP_IN) && |
46 | !(info->invert & XT_PHYSDEV_OP_IN)) |
47 | return false; |
48 | if ((info->bitmask & XT_PHYSDEV_OP_OUT) && |
49 | !(info->invert & XT_PHYSDEV_OP_OUT)) |
50 | return false; |
51 | return true; |
52 | } |
53 | |
54 | physdev = nf_bridge_get_physoutdev(skb); |
55 | outdev = physdev ? physdev->name : NULL; |
56 | |
57 | /* This only makes sense in the FORWARD and POSTROUTING chains */ |
58 | if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) && |
59 | (!!outdev ^ !(info->invert & XT_PHYSDEV_OP_BRIDGED))) |
60 | return false; |
61 | |
62 | physdev = nf_bridge_get_physindev(skb); |
63 | indev = physdev ? physdev->name : NULL; |
64 | |
65 | if ((info->bitmask & XT_PHYSDEV_OP_ISIN && |
66 | (!indev ^ !!(info->invert & XT_PHYSDEV_OP_ISIN))) || |
67 | (info->bitmask & XT_PHYSDEV_OP_ISOUT && |
68 | (!outdev ^ !!(info->invert & XT_PHYSDEV_OP_ISOUT)))) |
69 | return false; |
70 | |
71 | if (!(info->bitmask & XT_PHYSDEV_OP_IN)) |
72 | goto match_outdev; |
73 | |
74 | if (indev) { |
75 | ret = ifname_compare_aligned(a: indev, b: info->physindev, |
76 | mask: info->in_mask); |
77 | |
78 | if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN)) |
79 | return false; |
80 | } |
81 | |
82 | match_outdev: |
83 | if (!(info->bitmask & XT_PHYSDEV_OP_OUT)) |
84 | return true; |
85 | |
86 | if (!outdev) |
87 | return false; |
88 | |
89 | ret = ifname_compare_aligned(a: outdev, b: info->physoutdev, mask: info->out_mask); |
90 | |
91 | return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT)); |
92 | } |
93 | |
94 | static int physdev_mt_check(const struct xt_mtchk_param *par) |
95 | { |
96 | const struct xt_physdev_info *info = par->matchinfo; |
97 | static bool brnf_probed __read_mostly; |
98 | |
99 | if (!(info->bitmask & XT_PHYSDEV_OP_MASK) || |
100 | info->bitmask & ~XT_PHYSDEV_OP_MASK) |
101 | return -EINVAL; |
102 | if (info->bitmask & (XT_PHYSDEV_OP_OUT | XT_PHYSDEV_OP_ISOUT) && |
103 | (!(info->bitmask & XT_PHYSDEV_OP_BRIDGED) || |
104 | info->invert & XT_PHYSDEV_OP_BRIDGED) && |
105 | par->hook_mask & (1 << NF_INET_LOCAL_OUT)) { |
106 | pr_info_ratelimited("--physdev-out and --physdev-is-out only supported in the FORWARD and POSTROUTING chains with bridged traffic\n" ); |
107 | return -EINVAL; |
108 | } |
109 | |
110 | if (!brnf_probed) { |
111 | brnf_probed = true; |
112 | request_module("br_netfilter" ); |
113 | } |
114 | |
115 | return 0; |
116 | } |
117 | |
118 | static struct xt_match physdev_mt_reg __read_mostly = { |
119 | .name = "physdev" , |
120 | .revision = 0, |
121 | .family = NFPROTO_UNSPEC, |
122 | .checkentry = physdev_mt_check, |
123 | .match = physdev_mt, |
124 | .matchsize = sizeof(struct xt_physdev_info), |
125 | .me = THIS_MODULE, |
126 | }; |
127 | |
128 | static int __init physdev_mt_init(void) |
129 | { |
130 | return xt_register_match(target: &physdev_mt_reg); |
131 | } |
132 | |
133 | static void __exit physdev_mt_exit(void) |
134 | { |
135 | xt_unregister_match(target: &physdev_mt_reg); |
136 | } |
137 | |
138 | module_init(physdev_mt_init); |
139 | module_exit(physdev_mt_exit); |
140 | |