ebt_mark.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *  ebt_mark
  4 *
  5 *	Authors:
  6 *	Bart De Schuymer <bdschuym@pandora.be>
  7 *
  8 *  July, 2002
  9 *
 10 */
 11
 12/* The mark target can be used in any chain,
 13 * I believe adding a mangle table just for marking is total overkill.
 14 * Marking a frame doesn't really change anything in the frame anyway.
 15 */
 16
 17#include <linux/module.h>
 18#include <linux/netfilter/x_tables.h>
 19#include <linux/netfilter_bridge/ebtables.h>
 20#include <linux/netfilter_bridge/ebt_mark_t.h>
 21
 22static unsigned int
 23ebt_mark_tg(struct sk_buff *skb, const struct xt_action_param *par)
 24{
 25	const struct ebt_mark_t_info *info = par->targinfo;
 26	int action = info->target & -16;
 27
 28	if (action == MARK_SET_VALUE)
 29		skb->mark = info->mark;
 30	else if (action == MARK_OR_VALUE)
 31		skb->mark |= info->mark;
 32	else if (action == MARK_AND_VALUE)
 33		skb->mark &= info->mark;
 34	else
 35		skb->mark ^= info->mark;
 36
 37	return info->target | ~EBT_VERDICT_BITS;
 38}
 39
 40static int ebt_mark_tg_check(const struct xt_tgchk_param *par)
 41{
 42	const struct ebt_mark_t_info *info = par->targinfo;
 43	int tmp;
 44
 45	tmp = info->target | ~EBT_VERDICT_BITS;
 46	if (BASE_CHAIN && tmp == EBT_RETURN)
 47		return -EINVAL;
 48	if (ebt_invalid_target(tmp))
 49		return -EINVAL;
 50	tmp = info->target & ~EBT_VERDICT_BITS;
 51	if (tmp != MARK_SET_VALUE && tmp != MARK_OR_VALUE &&
 52	    tmp != MARK_AND_VALUE && tmp != MARK_XOR_VALUE)
 53		return -EINVAL;
 54	return 0;
 55}
 56#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
 57struct compat_ebt_mark_t_info {
 58	compat_ulong_t mark;
 59	compat_uint_t target;
 60};
 61
 62static void mark_tg_compat_from_user(void *dst, const void *src)
 63{
 64	const struct compat_ebt_mark_t_info *user = src;
 65	struct ebt_mark_t_info *kern = dst;
 66
 67	kern->mark = user->mark;
 68	kern->target = user->target;
 69}
 70
 71static int mark_tg_compat_to_user(void __user *dst, const void *src)
 72{
 73	struct compat_ebt_mark_t_info __user *user = dst;
 74	const struct ebt_mark_t_info *kern = src;
 75
 76	if (put_user(kern->mark, &user->mark) ||
 77	    put_user(kern->target, &user->target))
 78		return -EFAULT;
 79	return 0;
 80}
 81#endif
 82
 83static struct xt_target ebt_mark_tg_reg __read_mostly = {
 84	.name		= "mark",
 85	.revision	= 0,
 86	.family		= NFPROTO_BRIDGE,
 87	.target		= ebt_mark_tg,
 88	.checkentry	= ebt_mark_tg_check,
 89	.targetsize	= sizeof(struct ebt_mark_t_info),
 90#ifdef CONFIG_NETFILTER_XTABLES_COMPAT
 91	.compatsize	= sizeof(struct compat_ebt_mark_t_info),
 92	.compat_from_user = mark_tg_compat_from_user,
 93	.compat_to_user	= mark_tg_compat_to_user,
 94#endif
 95	.me		= THIS_MODULE,
 96};
 97
 98static int __init ebt_mark_init(void)
 99{
100	return xt_register_target(&ebt_mark_tg_reg);
101}
102
103static void __exit ebt_mark_fini(void)
104{
105	xt_unregister_target(&ebt_mark_tg_reg);
106}
107
108module_init(ebt_mark_init);
109module_exit(ebt_mark_fini);
110MODULE_DESCRIPTION("Ebtables: Packet mark modification");
111MODULE_LICENSE("GPL");