net/bridge/netfilter/ebt_mark.c

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