Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
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linux
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#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>
14
15MODULE_LICENSE("GPL");
16MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
17MODULE_DESCRIPTION("Xtables: Bridge physical device match");
18MODULE_ALIAS("ipt_physdev");
19MODULE_ALIAS("ip6t_physdev");
20
21
22static bool
23physdev_mt(const struct sk_buff *skb, struct xt_action_param *par)
24{
25 const struct xt_physdev_info *info = par->matchinfo;
26 const struct net_device *physdev;
27 unsigned long ret;
28 const char *indev, *outdev;
29
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))
37 return false;
38 if ((info->bitmask & XT_PHYSDEV_OP_ISIN) &&
39 !(info->invert & XT_PHYSDEV_OP_ISIN))
40 return false;
41 if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) &&
42 !(info->invert & XT_PHYSDEV_OP_ISOUT))
43 return false;
44 if ((info->bitmask & XT_PHYSDEV_OP_IN) &&
45 !(info->invert & XT_PHYSDEV_OP_IN))
46 return false;
47 if ((info->bitmask & XT_PHYSDEV_OP_OUT) &&
48 !(info->invert & XT_PHYSDEV_OP_OUT))
49 return false;
50 return true;
51 }
52
53 physdev = nf_bridge_get_physoutdev(skb);
54 outdev = physdev ? physdev->name : NULL;
55
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)))
59 return false;
60
61 physdev = nf_bridge_get_physindev(skb);
62 indev = physdev ? physdev->name : NULL;
63
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))))
68 return false;
69
70 if (!(info->bitmask & XT_PHYSDEV_OP_IN))
71 goto match_outdev;
72
73 if (indev) {
74 ret = ifname_compare_aligned(indev, info->physindev,
75 info->in_mask);
76
77 if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN))
78 return false;
79 }
80
81match_outdev:
82 if (!(info->bitmask & XT_PHYSDEV_OP_OUT))
83 return true;
84
85 if (!outdev)
86 return false;
87
88 ret = ifname_compare_aligned(outdev, info->physoutdev, info->out_mask);
89
90 return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT));
91}
92
93static int physdev_mt_check(const struct xt_mtchk_param *par)
94{
95 const struct xt_physdev_info *info = par->matchinfo;
96 static bool brnf_probed __read_mostly;
97
98 if (!(info->bitmask & XT_PHYSDEV_OP_MASK) ||
99 info->bitmask & ~XT_PHYSDEV_OP_MASK)
100 return -EINVAL;
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 (1 << NF_INET_FORWARD) | (1 << NF_INET_POST_ROUTING))) {
106 pr_info_ratelimited("--physdev-out and --physdev-is-out only supported in the FORWARD and POSTROUTING chains with bridged traffic\n");
107 if (par->hook_mask & (1 << NF_INET_LOCAL_OUT))
108 return -EINVAL;
109 }
110
111 if (!brnf_probed) {
112 brnf_probed = true;
113 request_module("br_netfilter");
114 }
115
116 return 0;
117}
118
119static struct xt_match physdev_mt_reg __read_mostly = {
120 .name = "physdev",
121 .revision = 0,
122 .family = NFPROTO_UNSPEC,
123 .checkentry = physdev_mt_check,
124 .match = physdev_mt,
125 .matchsize = sizeof(struct xt_physdev_info),
126 .me = THIS_MODULE,
127};
128
129static int __init physdev_mt_init(void)
130{
131 return xt_register_match(&physdev_mt_reg);
132}
133
134static void __exit physdev_mt_exit(void)
135{
136 xt_unregister_match(&physdev_mt_reg);
137}
138
139module_init(physdev_mt_init);
140module_exit(physdev_mt_exit);