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/netfilter_bridge/ebtables.h>
  17 #include <linux/netfilter_bridge/ebt_mark_t.h>
  18 #include <linux/module.h>
  19
  20 static int ebt_target_mark(struct sk_buff *skb, unsigned int hooknr,
  21    const struct net_device *in, const struct net_device *out,
  22    const void *data, unsigned int datalen)
  23 {
  24         const struct ebt_mark_t_info *info = data;
  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_target_mark_check(const char *tablename, unsigned int hookmask,
  40    const struct ebt_entry *e, void *data, unsigned int datalen)
  41 {
  42         const struct ebt_mark_t_info *info = data;
  43         int tmp;
  44
  45         if (datalen != EBT_ALIGN(sizeof(struct ebt_mark_t_info)))
  46                 return -EINVAL;
  47         tmp = info->target | ~EBT_VERDICT_BITS;
  48         if (BASE_CHAIN && tmp == EBT_RETURN)
  49                 return -EINVAL;
  50         CLEAR_BASE_CHAIN_BIT;
  51         if (tmp < -NUM_STANDARD_TARGETS || tmp >= 0)
  52                 return -EINVAL;
  53         tmp = info->target & ~EBT_VERDICT_BITS;
  54         if (tmp != MARK_SET_VALUE && tmp != MARK_OR_VALUE &&
  55             tmp != MARK_AND_VALUE && tmp != MARK_XOR_VALUE)
  56                 return -EINVAL;
  57         return 0;
  58 }
  59
  60 static struct ebt_target mark_target __read_mostly = {
  61         .name           = EBT_MARK_TARGET,
  62         .target         = ebt_target_mark,
  63         .check          = ebt_target_mark_check,
  64         .me             = THIS_MODULE,
  65 };
  66
  67 static int __init ebt_mark_init(void)
  68 {
  69         return ebt_register_target(&mark_target);
  70 }
  71
  72 static void __exit ebt_mark_fini(void)
  73 {
  74         ebt_unregister_target(&mark_target);
  75 }
  76
  77 module_init(ebt_mark_init);
  78 module_exit(ebt_mark_fini);
  79 MODULE_DESCRIPTION("Ebtables: Packet mark modification");
  80 MODULE_LICENSE("GPL");