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