Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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 <net/netfilter/br_netfilter.h>
17
18MODULE_LICENSE("GPL");
19MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
20MODULE_DESCRIPTION("Xtables: Bridge physical device match");
21MODULE_ALIAS("ipt_physdev");
22MODULE_ALIAS("ip6t_physdev");
23
24
25static bool
26physdev_mt(const struct sk_buff *skb, struct xt_action_param *par)
27{
28 static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
29 const struct xt_physdev_info *info = par->matchinfo;
30 unsigned long ret;
31 const char *indev, *outdev;
32 const struct nf_bridge_info *nf_bridge;
33
34 /* Not a bridged IP packet or no info available yet:
35 * LOCAL_OUT/mangle and LOCAL_OUT/nat don't know if
36 * the destination device will be a bridge. */
37 if (!(nf_bridge = skb->nf_bridge)) {
38 /* Return MATCH if the invert flags of the used options are on */
39 if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
40 !(info->invert & XT_PHYSDEV_OP_BRIDGED))
41 return false;
42 if ((info->bitmask & XT_PHYSDEV_OP_ISIN) &&
43 !(info->invert & XT_PHYSDEV_OP_ISIN))
44 return false;
45 if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) &&
46 !(info->invert & XT_PHYSDEV_OP_ISOUT))
47 return false;
48 if ((info->bitmask & XT_PHYSDEV_OP_IN) &&
49 !(info->invert & XT_PHYSDEV_OP_IN))
50 return false;
51 if ((info->bitmask & XT_PHYSDEV_OP_OUT) &&
52 !(info->invert & XT_PHYSDEV_OP_OUT))
53 return false;
54 return true;
55 }
56
57 /* This only makes sense in the FORWARD and POSTROUTING chains */
58 if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
59 (!!(nf_bridge->mask & BRNF_BRIDGED) ^
60 !(info->invert & XT_PHYSDEV_OP_BRIDGED)))
61 return false;
62
63 if ((info->bitmask & XT_PHYSDEV_OP_ISIN &&
64 (!nf_bridge->physindev ^ !!(info->invert & XT_PHYSDEV_OP_ISIN))) ||
65 (info->bitmask & XT_PHYSDEV_OP_ISOUT &&
66 (!nf_bridge->physoutdev ^ !!(info->invert & XT_PHYSDEV_OP_ISOUT))))
67 return false;
68
69 if (!(info->bitmask & XT_PHYSDEV_OP_IN))
70 goto match_outdev;
71 indev = nf_bridge->physindev ? nf_bridge->physindev->name : nulldevname;
72 ret = ifname_compare_aligned(indev, info->physindev, info->in_mask);
73
74 if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN))
75 return false;
76
77match_outdev:
78 if (!(info->bitmask & XT_PHYSDEV_OP_OUT))
79 return true;
80 outdev = nf_bridge->physoutdev ?
81 nf_bridge->physoutdev->name : nulldevname;
82 ret = ifname_compare_aligned(outdev, info->physoutdev, info->out_mask);
83
84 return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT));
85}
86
87static int physdev_mt_check(const struct xt_mtchk_param *par)
88{
89 const struct xt_physdev_info *info = par->matchinfo;
90
91 br_netfilter_enable();
92
93 if (!(info->bitmask & XT_PHYSDEV_OP_MASK) ||
94 info->bitmask & ~XT_PHYSDEV_OP_MASK)
95 return -EINVAL;
96 if (info->bitmask & XT_PHYSDEV_OP_OUT &&
97 (!(info->bitmask & XT_PHYSDEV_OP_BRIDGED) ||
98 info->invert & XT_PHYSDEV_OP_BRIDGED) &&
99 par->hook_mask & ((1 << NF_INET_LOCAL_OUT) |
100 (1 << NF_INET_FORWARD) | (1 << NF_INET_POST_ROUTING))) {
101 pr_info("using --physdev-out in the OUTPUT, FORWARD and "
102 "POSTROUTING chains for non-bridged traffic is not "
103 "supported anymore.\n");
104 if (par->hook_mask & (1 << NF_INET_LOCAL_OUT))
105 return -EINVAL;
106 }
107 return 0;
108}
109
110static struct xt_match physdev_mt_reg __read_mostly = {
111 .name = "physdev",
112 .revision = 0,
113 .family = NFPROTO_UNSPEC,
114 .checkentry = physdev_mt_check,
115 .match = physdev_mt,
116 .matchsize = sizeof(struct xt_physdev_info),
117 .me = THIS_MODULE,
118};
119
120static int __init physdev_mt_init(void)
121{
122 return xt_register_match(&physdev_mt_reg);
123}
124
125static void __exit physdev_mt_exit(void)
126{
127 xt_unregister_match(&physdev_mt_reg);
128}
129
130module_init(physdev_mt_init);
131module_exit(physdev_mt_exit);