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 #include <linux/netfilter_bridge.h> 17 18 MODULE_LICENSE("GPL"); 19 MODULE_AUTHOR("Bart De Schuymer <[email protected]>"); 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 const 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 bool 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 false; 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 false; 124 } 125 return true; 126 } 127 128 static struct xt_match xt_physdev_match[] __read_mostly = { 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); 160