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 net_device *in,
  23             const struct net_device *out, unsigned int hook_nr,
  24             const struct xt_target *target, const void *data)
  25 {
  26         const struct ebt_mark_t_info *info = data;
  27         int action = info->target & -16;
  28
  29         if (action == MARK_SET_VALUE)
  30                 skb->mark = info->mark;
  31         else if (action == MARK_OR_VALUE)
  32                 skb->mark |= info->mark;
  33         else if (action == MARK_AND_VALUE)
  34                 skb->mark &= info->mark;
  35         else
  36                 skb->mark ^= info->mark;
  37
  38         return info->target | ~EBT_VERDICT_BITS;
  39 }
  40
  41 static bool
  42 ebt_mark_tg_check(const char *table, const void *e,
  43                   const struct xt_target *target, void *data,
  44                   unsigned int hookmask)
  45 {
  46         const struct ebt_mark_t_info *info = data;
  47         int tmp;
  48
  49         tmp = info->target | ~EBT_VERDICT_BITS;
  50         if (BASE_CHAIN && tmp == EBT_RETURN)
  51                 return false;
  52         CLEAR_BASE_CHAIN_BIT;
  53         if (tmp < -NUM_STANDARD_TARGETS || tmp >= 0)
  54                 return false;
  55         tmp = info->target & ~EBT_VERDICT_BITS;
  56         if (tmp != MARK_SET_VALUE && tmp != MARK_OR_VALUE &&
  57             tmp != MARK_AND_VALUE && tmp != MARK_XOR_VALUE)
  58                 return false;
  59         return true;
  60 }
  61
  62 static struct xt_target ebt_mark_tg_reg __read_mostly = {
  63         .name           = "mark",
  64         .revision       = 0,
  65         .family         = NFPROTO_BRIDGE,
  66         .target         = ebt_mark_tg,
  67         .checkentry     = ebt_mark_tg_check,
  68         .targetsize     = XT_ALIGN(sizeof(struct ebt_mark_t_info)),
  69         .me             = THIS_MODULE,
  70 };
  71
  72 static int __init ebt_mark_init(void)
  73 {
  74         return xt_register_target(&ebt_mark_tg_reg);
  75 }
  76
  77 static void __exit ebt_mark_fini(void)
  78 {
  79         xt_unregister_target(&ebt_mark_tg_reg);
  80 }
  81
  82 module_init(ebt_mark_init);
  83 module_exit(ebt_mark_fini);
  84 MODULE_DESCRIPTION("Ebtables: Packet mark modification");
  85 MODULE_LICENSE("GPL");