net/bridge/netfilter/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
  22 static unsigned int
  23 ebt_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
  40 static 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
  57 struct compat_ebt_mark_t_info {
  58         compat_ulong_t mark;
  59         compat_uint_t target;
  60 };
  61
  62 static 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
  71 static 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
  83 static 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
  98 static int __init ebt_mark_init(void)
  99 {
 100         return xt_register_target(&ebt_mark_tg_reg);
 101 }
 102
 103 static void __exit ebt_mark_fini(void)
 104 {
 105         xt_unregister_target(&ebt_mark_tg_reg);
 106 }
 107
 108 module_init(ebt_mark_init);
 109 module_exit(ebt_mark_fini);
 110 MODULE_DESCRIPTION("Ebtables: Packet mark modification");
 111 MODULE_LICENSE("GPL");