135 lines
3.9 KiB
C
135 lines
3.9 KiB
C
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/* Kernel module to match the bridge port in and
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* out device for IP packets coming into contact with a bridge. */
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/* (C) 2001-2003 Bart De Schuymer <bdschuym@pandora.be>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter_ipv4/ipt_physdev.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_bridge.h>
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#define MATCH 1
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#define NOMATCH 0
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
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MODULE_DESCRIPTION("iptables bridge physical device match module");
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static int
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match(const struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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const void *matchinfo,
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int offset,
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int *hotdrop)
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{
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int i;
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static const char nulldevname[IFNAMSIZ];
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const struct ipt_physdev_info *info = matchinfo;
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unsigned int ret;
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const char *indev, *outdev;
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struct nf_bridge_info *nf_bridge;
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/* Not a bridged IP packet or no info available yet:
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* LOCAL_OUT/mangle and LOCAL_OUT/nat don't know if
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* the destination device will be a bridge. */
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if (!(nf_bridge = skb->nf_bridge)) {
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/* Return MATCH if the invert flags of the used options are on */
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if ((info->bitmask & IPT_PHYSDEV_OP_BRIDGED) &&
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!(info->invert & IPT_PHYSDEV_OP_BRIDGED))
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return NOMATCH;
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if ((info->bitmask & IPT_PHYSDEV_OP_ISIN) &&
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!(info->invert & IPT_PHYSDEV_OP_ISIN))
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return NOMATCH;
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if ((info->bitmask & IPT_PHYSDEV_OP_ISOUT) &&
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!(info->invert & IPT_PHYSDEV_OP_ISOUT))
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return NOMATCH;
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if ((info->bitmask & IPT_PHYSDEV_OP_IN) &&
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!(info->invert & IPT_PHYSDEV_OP_IN))
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return NOMATCH;
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if ((info->bitmask & IPT_PHYSDEV_OP_OUT) &&
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!(info->invert & IPT_PHYSDEV_OP_OUT))
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return NOMATCH;
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return MATCH;
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}
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/* This only makes sense in the FORWARD and POSTROUTING chains */
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if ((info->bitmask & IPT_PHYSDEV_OP_BRIDGED) &&
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(!!(nf_bridge->mask & BRNF_BRIDGED) ^
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!(info->invert & IPT_PHYSDEV_OP_BRIDGED)))
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return NOMATCH;
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if ((info->bitmask & IPT_PHYSDEV_OP_ISIN &&
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(!nf_bridge->physindev ^ !!(info->invert & IPT_PHYSDEV_OP_ISIN))) ||
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(info->bitmask & IPT_PHYSDEV_OP_ISOUT &&
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(!nf_bridge->physoutdev ^ !!(info->invert & IPT_PHYSDEV_OP_ISOUT))))
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return NOMATCH;
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if (!(info->bitmask & IPT_PHYSDEV_OP_IN))
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goto match_outdev;
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indev = nf_bridge->physindev ? nf_bridge->physindev->name : nulldevname;
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for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned int); i++) {
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ret |= (((const unsigned int *)indev)[i]
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^ ((const unsigned int *)info->physindev)[i])
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& ((const unsigned int *)info->in_mask)[i];
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}
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if ((ret == 0) ^ !(info->invert & IPT_PHYSDEV_OP_IN))
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return NOMATCH;
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match_outdev:
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if (!(info->bitmask & IPT_PHYSDEV_OP_OUT))
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return MATCH;
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outdev = nf_bridge->physoutdev ?
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nf_bridge->physoutdev->name : nulldevname;
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for (i = 0, ret = 0; i < IFNAMSIZ/sizeof(unsigned int); i++) {
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ret |= (((const unsigned int *)outdev)[i]
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^ ((const unsigned int *)info->physoutdev)[i])
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& ((const unsigned int *)info->out_mask)[i];
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}
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return (ret != 0) ^ !(info->invert & IPT_PHYSDEV_OP_OUT);
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}
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static int
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checkentry(const char *tablename,
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const struct ipt_ip *ip,
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void *matchinfo,
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unsigned int matchsize,
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unsigned int hook_mask)
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{
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const struct ipt_physdev_info *info = matchinfo;
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if (matchsize != IPT_ALIGN(sizeof(struct ipt_physdev_info)))
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return 0;
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if (!(info->bitmask & IPT_PHYSDEV_OP_MASK) ||
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info->bitmask & ~IPT_PHYSDEV_OP_MASK)
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return 0;
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return 1;
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}
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static struct ipt_match physdev_match = {
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.name = "physdev",
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.match = &match,
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.checkentry = &checkentry,
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.me = THIS_MODULE,
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};
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static int __init init(void)
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{
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return ipt_register_match(&physdev_match);
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}
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static void __exit fini(void)
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{
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ipt_unregister_match(&physdev_match);
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}
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module_init(init);
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module_exit(fini);
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