Contributors: 12
Author Tokens Token Proportion Commits Commit Proportion
Bart De Schuymer 417 49.88% 1 2.86%
Florian Westphal 161 19.26% 5 14.29%
Harald Welte 67 8.01% 1 2.86%
Jan Engelhardt 58 6.94% 9 25.71%
Patrick McHardy 55 6.58% 7 20.00%
Pablo Neira Ayuso 44 5.26% 4 11.43%
Eric Dumazet 16 1.91% 3 8.57%
Jeremy Sowden 5 0.60% 1 2.86%
Pavel Tikhomirov 5 0.60% 1 2.86%
Hangbin Liu 4 0.48% 1 2.86%
Andrew Morton 2 0.24% 1 2.86%
Thomas Gleixner 2 0.24% 1 2.86%
Total 836 35 


// SPDX-License-Identifier: GPL-2.0-only
/* Kernel module to match the bridge port in and
 * out device for IP packets coming into contact with a bridge. */

/* (C) 2001-2003 Bart De Schuymer <bdschuym@pandora.be>
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/if.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netfilter_bridge.h>
#include <linux/netfilter/x_tables.h>
#include <uapi/linux/netfilter/xt_physdev.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Bart De Schuymer <bdschuym@pandora.be>");
MODULE_DESCRIPTION("Xtables: Bridge physical device match");
MODULE_ALIAS("ipt_physdev");
MODULE_ALIAS("ip6t_physdev");


static bool
physdev_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_physdev_info *info = par->matchinfo;
	const struct net_device *physdev;
	unsigned long ret;
	const char *indev, *outdev;

	/* Not a bridged IP packet or no info available yet:
	 * LOCAL_OUT/mangle and LOCAL_OUT/nat don't know if
	 * the destination device will be a bridge. */
	if (!nf_bridge_info_exists(skb)) {
		/* Return MATCH if the invert flags of the used options are on */
		if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
		    !(info->invert & XT_PHYSDEV_OP_BRIDGED))
			return false;
		if ((info->bitmask & XT_PHYSDEV_OP_ISIN) &&
		    !(info->invert & XT_PHYSDEV_OP_ISIN))
			return false;
		if ((info->bitmask & XT_PHYSDEV_OP_ISOUT) &&
		    !(info->invert & XT_PHYSDEV_OP_ISOUT))
			return false;
		if ((info->bitmask & XT_PHYSDEV_OP_IN) &&
		    !(info->invert & XT_PHYSDEV_OP_IN))
			return false;
		if ((info->bitmask & XT_PHYSDEV_OP_OUT) &&
		    !(info->invert & XT_PHYSDEV_OP_OUT))
			return false;
		return true;
	}

	physdev = nf_bridge_get_physoutdev(skb);
	outdev = physdev ? physdev->name : NULL;

	/* This only makes sense in the FORWARD and POSTROUTING chains */
	if ((info->bitmask & XT_PHYSDEV_OP_BRIDGED) &&
	    (!!outdev ^ !(info->invert & XT_PHYSDEV_OP_BRIDGED)))
		return false;

	physdev = nf_bridge_get_physindev(skb, xt_net(par));
	indev = physdev ? physdev->name : NULL;

	if ((info->bitmask & XT_PHYSDEV_OP_ISIN &&
	    (!indev ^ !!(info->invert & XT_PHYSDEV_OP_ISIN))) ||
	    (info->bitmask & XT_PHYSDEV_OP_ISOUT &&
	    (!outdev ^ !!(info->invert & XT_PHYSDEV_OP_ISOUT))))
		return false;

	if (!(info->bitmask & XT_PHYSDEV_OP_IN))
		goto match_outdev;

	if (indev) {
		ret = ifname_compare_aligned(indev, info->physindev,
					     info->in_mask);

		if (!ret ^ !(info->invert & XT_PHYSDEV_OP_IN))
			return false;
	}

match_outdev:
	if (!(info->bitmask & XT_PHYSDEV_OP_OUT))
		return true;

	if (!outdev)
		return false;

	ret = ifname_compare_aligned(outdev, info->physoutdev, info->out_mask);

	return (!!ret ^ !(info->invert & XT_PHYSDEV_OP_OUT));
}

static int physdev_mt_check_hooks(const struct xt_mtchk_param *par)
{
	const struct xt_physdev_info *info = par->matchinfo;

	if (info->bitmask & (XT_PHYSDEV_OP_OUT | XT_PHYSDEV_OP_ISOUT) &&
	    (!(info->bitmask & XT_PHYSDEV_OP_BRIDGED) ||
	     info->invert & XT_PHYSDEV_OP_BRIDGED) &&
	    par->hook_mask & (1 << NF_INET_LOCAL_OUT)) {
		pr_info_ratelimited("--physdev-out and --physdev-is-out only supported in the FORWARD and POSTROUTING chains with bridged traffic\n");
		return -EINVAL;
	}

	return 0;
}

static int physdev_mt_check(const struct xt_mtchk_param *par)
{
	const struct xt_physdev_info *info = par->matchinfo;
	static bool brnf_probed __read_mostly;

	if (!(info->bitmask & XT_PHYSDEV_OP_MASK) ||
	    info->bitmask & ~XT_PHYSDEV_OP_MASK)
		return -EINVAL;

#define X(memb) strnlen(info->memb, sizeof(info->memb)) >= sizeof(info->memb)
	if (info->bitmask & XT_PHYSDEV_OP_IN) {
		if (info->physindev[0] == '\0')
			return -EINVAL;
		if (X(physindev))
			return -ENAMETOOLONG;
	}

	if (info->bitmask & XT_PHYSDEV_OP_OUT) {
		if (info->physoutdev[0] == '\0')
			return -EINVAL;

		if (X(physoutdev))
			return -ENAMETOOLONG;
	}

	if (X(in_mask))
		return -ENAMETOOLONG;
	if (X(out_mask))
		return -ENAMETOOLONG;
#undef X

	if (!brnf_probed) {
		brnf_probed = true;
		request_module("br_netfilter");
	}

	return 0;
}

static struct xt_match physdev_mt_reg[] __read_mostly = {
	{
		.name		= "physdev",
		.family		= NFPROTO_IPV4,
		.check_hooks	= physdev_mt_check_hooks,
		.checkentry	= physdev_mt_check,
		.match		= physdev_mt,
		.matchsize	= sizeof(struct xt_physdev_info),
		.me		= THIS_MODULE,
	},
	{
		.name		= "physdev",
		.family		= NFPROTO_IPV6,
		.check_hooks	= physdev_mt_check_hooks,
		.checkentry	= physdev_mt_check,
		.match		= physdev_mt,
		.matchsize	= sizeof(struct xt_physdev_info),
		.me		= THIS_MODULE,
	},
};

static int __init physdev_mt_init(void)
{
	return xt_register_matches(physdev_mt_reg, ARRAY_SIZE(physdev_mt_reg));
}

static void __exit physdev_mt_exit(void)
{
	xt_unregister_matches(physdev_mt_reg, ARRAY_SIZE(physdev_mt_reg));
}

module_init(physdev_mt_init);
module_exit(physdev_mt_exit);