Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame^] | 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/xt_physdev.h> |
| 14 | #include <linux/netfilter/x_tables.h> |
| 15 | #include <linux/netfilter_bridge.h> |
| 16 | #define MATCH 1 |
| 17 | #define NOMATCH 0 |
| 18 | |
| 19 | MODULE_LICENSE("GPL"); |
| 20 | MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>"); |
| 21 | MODULE_DESCRIPTION("iptables bridge physical device match module"); |
| 22 | MODULE_ALIAS("ipt_physdev"); |
| 23 | MODULE_ALIAS("ip6t_physdev"); |
| 24 | |
| 25 | static int |
| 26 | match(const struct sk_buff *skb, |
| 27 | const struct net_device *in, |
| 28 | const struct net_device *out, |
| 29 | const void *matchinfo, |
| 30 | int offset, |
| 31 | unsigned int protoff, |
| 32 | int *hotdrop) |
| 33 | { |
| 34 | int i; |
| 35 | static const char nulldevname[IFNAMSIZ]; |
| 36 | const struct xt_physdev_info *info = matchinfo; |
| 37 | unsigned int 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 NOMATCH; |
| 49 | if ((info->bitmask & XT_PHYSDEV_OP_ISIN) && |
| 50 | !(info->invert & XT_PHYSDEV_OP_ISIN)) |
| 51 | return NOMATCH; |
| 52 | if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) && |
| 53 | !(info->invert & XT_PHYSDEV_OP_ISOUT)) |
| 54 | return NOMATCH; |
| 55 | if ((info->bitmask & XT_PHYSDEV_OP_IN) && |
| 56 | !(info->invert & XT_PHYSDEV_OP_IN)) |
| 57 | return NOMATCH; |
| 58 | if ((info->bitmask & XT_PHYSDEV_OP_OUT) && |
| 59 | !(info->invert & XT_PHYSDEV_OP_OUT)) |
| 60 | return NOMATCH; |
| 61 | return MATCH; |
| 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 NOMATCH; |
| 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 NOMATCH; |
| 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 = 0; 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 == 0) ^ !(info->invert & XT_PHYSDEV_OP_IN)) |
| 86 | return NOMATCH; |
| 87 | |
| 88 | match_outdev: |
| 89 | if (!(info->bitmask & XT_PHYSDEV_OP_OUT)) |
| 90 | return MATCH; |
| 91 | outdev = nf_bridge->physoutdev ? |
| 92 | nf_bridge->physoutdev->name : nulldevname; |
| 93 | for (i = 0, ret = 0; 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 != 0) ^ !(info->invert & XT_PHYSDEV_OP_OUT); |
| 100 | } |
| 101 | |
| 102 | static int |
| 103 | checkentry(const char *tablename, |
| 104 | const void *ip, |
| 105 | void *matchinfo, |
| 106 | unsigned int matchsize, |
| 107 | unsigned int hook_mask) |
| 108 | { |
| 109 | const struct xt_physdev_info *info = matchinfo; |
| 110 | |
| 111 | if (matchsize != XT_ALIGN(sizeof(struct xt_physdev_info))) |
| 112 | return 0; |
| 113 | if (!(info->bitmask & XT_PHYSDEV_OP_MASK) || |
| 114 | info->bitmask & ~XT_PHYSDEV_OP_MASK) |
| 115 | return 0; |
| 116 | return 1; |
| 117 | } |
| 118 | |
| 119 | static struct xt_match physdev_match = { |
| 120 | .name = "physdev", |
| 121 | .match = &match, |
| 122 | .checkentry = &checkentry, |
| 123 | .me = THIS_MODULE, |
| 124 | }; |
| 125 | |
| 126 | static struct xt_match physdev6_match = { |
| 127 | .name = "physdev", |
| 128 | .match = &match, |
| 129 | .checkentry = &checkentry, |
| 130 | .me = THIS_MODULE, |
| 131 | }; |
| 132 | |
| 133 | static int __init init(void) |
| 134 | { |
| 135 | int ret; |
| 136 | |
| 137 | ret = xt_register_match(AF_INET, &physdev_match); |
| 138 | if (ret < 0) |
| 139 | return ret; |
| 140 | |
| 141 | ret = xt_register_match(AF_INET6, &physdev6_match); |
| 142 | if (ret < 0) |
| 143 | xt_unregister_match(AF_INET, &physdev_match); |
| 144 | |
| 145 | return ret; |
| 146 | } |
| 147 | |
| 148 | static void __exit fini(void) |
| 149 | { |
| 150 | xt_unregister_match(AF_INET, &physdev_match); |
| 151 | xt_unregister_match(AF_INET6, &physdev6_match); |
| 152 | } |
| 153 | |
| 154 | module_init(init); |
| 155 | module_exit(fini); |