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