LXR linux/net/bridge/netfilter/ebt

   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_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_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");
 112