net/sched/em_u32.c

   1 /*
   2  * net/sched/em_u32.c   U32 Ematch
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Thomas Graf <tgraf@suug.ch>
  10  *              Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  11  *
  12  * Based on net/sched/cls_u32.c
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/skbuff.h>
  19 #include <net/pkt_cls.h>
  20
  21 static int em_u32_match(struct sk_buff *skb, struct tcf_ematch *em,
  22                         struct tcf_pkt_info *info)
  23 {
  24         struct tc_u32_key *key = (struct tc_u32_key *) em->data;
  25         const unsigned char *ptr = skb_network_header(skb);
  26
  27         if (info) {
  28                 if (info->ptr)
  29                         ptr = info->ptr;
  30                 ptr += (info->nexthdr & key->offmask);
  31         }
  32
  33         ptr += key->off;
  34
  35         if (!tcf_valid_offset(skb, ptr, sizeof(u32)))
  36                 return 0;
  37
  38         return !(((*(u32*) ptr)  ^ key->val) & key->mask);
  39 }
  40
  41 static struct tcf_ematch_ops em_u32_ops = {
  42         .kind     = TCF_EM_U32,
  43         .datalen  = sizeof(struct tc_u32_key),
  44         .match    = em_u32_match,
  45         .owner    = THIS_MODULE,
  46         .link     = LIST_HEAD_INIT(em_u32_ops.link)
  47 };
  48
  49 static int __init init_em_u32(void)
  50 {
  51         return tcf_em_register(&em_u32_ops);
  52 }
  53
  54 static void __exit exit_em_u32(void)
  55 {
  56         tcf_em_unregister(&em_u32_ops);
  57 }
  58
  59 MODULE_LICENSE("GPL");
  60
  61 module_init(init_em_u32);
  62 module_exit(exit_em_u32);
  63
  64 MODULE_ALIAS_TCF_EMATCH(TCF_EM_U32);