net/sched/em_u32.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * net/sched/em_u32.c   U32 Ematch
0004  *
0005  * Authors: Thomas Graf <tgraf@suug.ch>
0006  *      Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
0007  *
0008  * Based on net/sched/cls_u32.c
0009  */
0010
0011 #include <linux/module.h>
0012 #include <linux/types.h>
0013 #include <linux/kernel.h>
0014 #include <linux/skbuff.h>
0015 #include <net/pkt_cls.h>
0016
0017 static int em_u32_match(struct sk_buff *skb, struct tcf_ematch *em,
0018             struct tcf_pkt_info *info)
0019 {
0020     struct tc_u32_key *key = (struct tc_u32_key *) em->data;
0021     const unsigned char *ptr = skb_network_header(skb);
0022
0023     if (info) {
0024         if (info->ptr)
0025             ptr = info->ptr;
0026         ptr += (info->nexthdr & key->offmask);
0027     }
0028
0029     ptr += key->off;
0030
0031     if (!tcf_valid_offset(skb, ptr, sizeof(u32)))
0032         return 0;
0033
0034     return !(((*(__be32 *) ptr)  ^ key->val) & key->mask);
0035 }
0036
0037 static struct tcf_ematch_ops em_u32_ops = {
0038     .kind     = TCF_EM_U32,
0039     .datalen  = sizeof(struct tc_u32_key),
0040     .match    = em_u32_match,
0041     .owner    = THIS_MODULE,
0042     .link     = LIST_HEAD_INIT(em_u32_ops.link)
0043 };
0044
0045 static int __init init_em_u32(void)
0046 {
0047     return tcf_em_register(&em_u32_ops);
0048 }
0049
0050 static void __exit exit_em_u32(void)
0051 {
0052     tcf_em_unregister(&em_u32_ops);
0053 }
0054
0055 MODULE_LICENSE("GPL");
0056
0057 module_init(init_em_u32);
0058 module_exit(exit_em_u32);
0059
0060 MODULE_ALIAS_TCF_EMATCH(TCF_EM_U32);