4b7fd5d97e
You can use physdev to match the physical interface enslaved to the
bridge device. This information is stored in skb->nf_bridge and it is
set up by br_netfilter. So, this is only available when iptables is
used from the bridge netfilter path.
Since 34666d4 ("netfilter: bridge: move br_netfilter out of the core"),
the br_netfilter code is modular. To reduce the impact of this change,
we can autoload the br_netfilter if the physdev match is used since
we assume that the users need br_netfilter in place.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
132 lines
4.1 KiB
C
132 lines
4.1 KiB
C
/* 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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter_bridge.h>
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#include <linux/netfilter/xt_physdev.h>
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#include <linux/netfilter/x_tables.h>
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#include <net/netfilter/br_netfilter.h>
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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("Xtables: Bridge physical device match");
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MODULE_ALIAS("ipt_physdev");
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MODULE_ALIAS("ip6t_physdev");
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static bool
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physdev_mt(const struct sk_buff *skb, struct xt_action_param *par)
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{
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static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
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const struct xt_physdev_info *info = par->matchinfo;
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unsigned long ret;
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const char *indev, *outdev;
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const 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 & XT_PHYSDEV_OP_BRIDGED) &&
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!(info->invert & XT_PHYSDEV_OP_BRIDGED))
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return false;
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if ((info->bitmask & XT_PHYSDEV_OP_ISIN) &&
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!(info->invert & XT_PHYSDEV_OP_ISIN))
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return false;
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if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) &&
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!(info->invert & XT_PHYSDEV_OP_ISOUT))
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return false;
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if ((info->bitmask & XT_PHYSDEV_OP_IN) &&
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!(info->invert & XT_PHYSDEV_OP_IN))
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return false;
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if ((info->bitmask & XT_PHYSDEV_OP_OUT) &&
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!(info->invert & XT_PHYSDEV_OP_OUT))
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return false;
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return true;
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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 & XT_PHYSDEV_OP_BRIDGED) &&
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(!!(nf_bridge->mask & BRNF_BRIDGED) ^
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!(info->invert & XT_PHYSDEV_OP_BRIDGED)))
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return false;
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if ((info->bitmask & XT_PHYSDEV_OP_ISIN &&
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(!nf_bridge->physindev ^ !!(info->invert & XT_PHYSDEV_OP_ISIN))) ||
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(info->bitmask & XT_PHYSDEV_OP_ISOUT &&
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(!nf_bridge->physoutdev ^ !!(info->invert & XT_PHYSDEV_OP_ISOUT))))
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return false;
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if (!(info->bitmask & XT_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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ret = ifname_compare_aligned(indev, info->physindev, info->in_mask);
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if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN))
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return false;
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match_outdev:
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if (!(info->bitmask & XT_PHYSDEV_OP_OUT))
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return true;
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outdev = nf_bridge->physoutdev ?
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nf_bridge->physoutdev->name : nulldevname;
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ret = ifname_compare_aligned(outdev, info->physoutdev, info->out_mask);
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return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT));
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}
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static int physdev_mt_check(const struct xt_mtchk_param *par)
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{
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const struct xt_physdev_info *info = par->matchinfo;
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br_netfilter_enable();
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if (!(info->bitmask & XT_PHYSDEV_OP_MASK) ||
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info->bitmask & ~XT_PHYSDEV_OP_MASK)
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return -EINVAL;
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if (info->bitmask & XT_PHYSDEV_OP_OUT &&
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(!(info->bitmask & XT_PHYSDEV_OP_BRIDGED) ||
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info->invert & XT_PHYSDEV_OP_BRIDGED) &&
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par->hook_mask & ((1 << NF_INET_LOCAL_OUT) |
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(1 << NF_INET_FORWARD) | (1 << NF_INET_POST_ROUTING))) {
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pr_info("using --physdev-out in the OUTPUT, FORWARD and "
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"POSTROUTING chains for non-bridged traffic is not "
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"supported anymore.\n");
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if (par->hook_mask & (1 << NF_INET_LOCAL_OUT))
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return -EINVAL;
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}
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return 0;
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}
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static struct xt_match physdev_mt_reg __read_mostly = {
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.name = "physdev",
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.revision = 0,
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.family = NFPROTO_UNSPEC,
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.checkentry = physdev_mt_check,
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.match = physdev_mt,
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.matchsize = sizeof(struct xt_physdev_info),
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.me = THIS_MODULE,
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};
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static int __init physdev_mt_init(void)
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{
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return xt_register_match(&physdev_mt_reg);
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}
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static void __exit physdev_mt_exit(void)
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{
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xt_unregister_match(&physdev_mt_reg);
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}
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module_init(physdev_mt_init);
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module_exit(physdev_mt_exit);
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