70de6708e8842c97cc7168b5fd88537f93e02c31
[linux-2.6.git] / net / netfilter / xt_physdev.c
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
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 <linux/netfilter_bridge.h>
17
18 MODULE_LICENSE("GPL");
19 MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
20 MODULE_DESCRIPTION("iptables bridge physical device match module");
21 MODULE_ALIAS("ipt_physdev");
22 MODULE_ALIAS("ip6t_physdev");
23
24 static bool
25 match(const struct sk_buff *skb,
26       const struct net_device *in,
27       const struct net_device *out,
28       const struct xt_match *match,
29       const void *matchinfo,
30       int offset,
31       unsigned int protoff,
32       bool *hotdrop)
33 {
34         int i;
35         static const char nulldevname[IFNAMSIZ];
36         const struct xt_physdev_info *info = matchinfo;
37         bool ret;
38         const char *indev, *outdev;
39         struct nf_bridge_info *nf_bridge;
40
41         /* Not a bridged IP packet or no info available yet:
42          * LOCAL_OUT/mangle and LOCAL_OUT/nat don't know if
43          * the destination device will be a bridge. */
44         if (!(nf_bridge = skb->nf_bridge)) {
45                 /* Return MATCH if the invert flags of the used options are on */
46                 if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
47                     !(info->invert & XT_PHYSDEV_OP_BRIDGED))
48                         return false;
49                 if ((info->bitmask & XT_PHYSDEV_OP_ISIN) &&
50                     !(info->invert & XT_PHYSDEV_OP_ISIN))
51                         return false;
52                 if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) &&
53                     !(info->invert & XT_PHYSDEV_OP_ISOUT))
54                         return false;
55                 if ((info->bitmask & XT_PHYSDEV_OP_IN) &&
56                     !(info->invert & XT_PHYSDEV_OP_IN))
57                         return false;
58                 if ((info->bitmask & XT_PHYSDEV_OP_OUT) &&
59                     !(info->invert & XT_PHYSDEV_OP_OUT))
60                         return false;
61                 return true;
62         }
63
64         /* This only makes sense in the FORWARD and POSTROUTING chains */
65         if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
66             (!!(nf_bridge->mask & BRNF_BRIDGED) ^
67             !(info->invert & XT_PHYSDEV_OP_BRIDGED)))
68                 return false;
69
70         if ((info->bitmask & XT_PHYSDEV_OP_ISIN &&
71             (!nf_bridge->physindev ^ !!(info->invert & XT_PHYSDEV_OP_ISIN))) ||
72             (info->bitmask & XT_PHYSDEV_OP_ISOUT &&
73             (!nf_bridge->physoutdev ^ !!(info->invert & XT_PHYSDEV_OP_ISOUT))))
74                 return false;
75
76         if (!(info->bitmask & XT_PHYSDEV_OP_IN))
77                 goto match_outdev;
78         indev = nf_bridge->physindev ? nf_bridge->physindev->name : nulldevname;
79         for (i = 0, ret = false; i < IFNAMSIZ/sizeof(unsigned int); i++) {
80                 ret |= (((const unsigned int *)indev)[i]
81                         ^ ((const unsigned int *)info->physindev)[i])
82                         & ((const unsigned int *)info->in_mask)[i];
83         }
84
85         if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN))
86                 return false;
87
88 match_outdev:
89         if (!(info->bitmask & XT_PHYSDEV_OP_OUT))
90                 return true;
91         outdev = nf_bridge->physoutdev ?
92                  nf_bridge->physoutdev->name : nulldevname;
93         for (i = 0, ret = false; i < IFNAMSIZ/sizeof(unsigned int); i++) {
94                 ret |= (((const unsigned int *)outdev)[i]
95                         ^ ((const unsigned int *)info->physoutdev)[i])
96                         & ((const unsigned int *)info->out_mask)[i];
97         }
98
99         return ret ^ !(info->invert & XT_PHYSDEV_OP_OUT);
100 }
101
102 static int
103 checkentry(const char *tablename,
104                        const void *ip,
105                        const struct xt_match *match,
106                        void *matchinfo,
107                        unsigned int hook_mask)
108 {
109         const struct xt_physdev_info *info = matchinfo;
110
111         if (!(info->bitmask & XT_PHYSDEV_OP_MASK) ||
112             info->bitmask & ~XT_PHYSDEV_OP_MASK)
113                 return 0;
114         if (info->bitmask & XT_PHYSDEV_OP_OUT &&
115             (!(info->bitmask & XT_PHYSDEV_OP_BRIDGED) ||
116              info->invert & XT_PHYSDEV_OP_BRIDGED) &&
117             hook_mask & ((1 << NF_IP_LOCAL_OUT) | (1 << NF_IP_FORWARD) |
118                          (1 << NF_IP_POST_ROUTING))) {
119                 printk(KERN_WARNING "physdev match: using --physdev-out in the "
120                        "OUTPUT, FORWARD and POSTROUTING chains for non-bridged "
121                        "traffic is not supported anymore.\n");
122                 if (hook_mask & (1 << NF_IP_LOCAL_OUT))
123                         return 0;
124         }
125         return 1;
126 }
127
128 static struct xt_match xt_physdev_match[] = {
129         {
130                 .name           = "physdev",
131                 .family         = AF_INET,
132                 .checkentry     = checkentry,
133                 .match          = match,
134                 .matchsize      = sizeof(struct xt_physdev_info),
135                 .me             = THIS_MODULE,
136         },
137         {
138                 .name           = "physdev",
139                 .family         = AF_INET6,
140                 .checkentry     = checkentry,
141                 .match          = match,
142                 .matchsize      = sizeof(struct xt_physdev_info),
143                 .me             = THIS_MODULE,
144         },
145 };
146
147 static int __init xt_physdev_init(void)
148 {
149         return xt_register_matches(xt_physdev_match,
150                                    ARRAY_SIZE(xt_physdev_match));
151 }
152
153 static void __exit xt_physdev_fini(void)
154 {
155         xt_unregister_matches(xt_physdev_match, ARRAY_SIZE(xt_physdev_match));
156 }
157
158 module_init(xt_physdev_init);
159 module_exit(xt_physdev_fini);