net/sched/em_u32.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/sched/em_u32.c   U32 Ematch
   4  *
   5  * Authors:     Thomas Graf <tgraf@suug.ch>
   6  *              Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   7  *
   8  * Based on net/sched/cls_u32.c
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/types.h>
  13 #include <linux/kernel.h>
  14 #include <linux/skbuff.h>
  15 #include <net/pkt_cls.h>
  16
  17 static int em_u32_match(struct sk_buff *skb, struct tcf_ematch *em,
  18                         struct tcf_pkt_info *info)
  19 {
  20         struct tc_u32_key *key = (struct tc_u32_key *) em->data;
  21         const unsigned char *ptr = skb_network_header(skb);
  22
  23         if (info) {
  24                 if (info->ptr)
  25                         ptr = info->ptr;
  26                 ptr += (info->nexthdr & key->offmask);
  27         }
  28
  29         ptr += key->off;
  30
  31         if (!tcf_valid_offset(skb, ptr, sizeof(u32)))
  32                 return 0;
  33
  34         return !(((*(__be32 *) ptr)  ^ key->val) & key->mask);
  35 }
  36
  37 static struct tcf_ematch_ops em_u32_ops = {
  38         .kind     = TCF_EM_U32,
  39         .datalen  = sizeof(struct tc_u32_key),
  40         .match    = em_u32_match,
  41         .owner    = THIS_MODULE,
  42         .link     = LIST_HEAD_INIT(em_u32_ops.link)
  43 };
  44
  45 static int __init init_em_u32(void)
  46 {
  47         return tcf_em_register(&em_u32_ops);
  48 }
  49
  50 static void __exit exit_em_u32(void)
  51 {
  52         tcf_em_unregister(&em_u32_ops);
  53 }
  54
  55 MODULE_LICENSE("GPL");
  56
  57 module_init(init_em_u32);
  58 module_exit(exit_em_u32);
  59
  60 MODULE_ALIAS_TCF_EMATCH(TCF_EM_U32);