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