LXR linux/net/sched/em

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * net/sched/em_nbyte.c N-Byte ematch
   4 *
   5 * Authors:     Thomas Graf <tgraf@suug.ch>
   6 */
   7
   8#include <linux/gfp.h>
   9#include <linux/module.h>
  10#include <linux/types.h>
  11#include <linux/kernel.h>
  12#include <linux/string.h>
  13#include <linux/skbuff.h>
  14#include <linux/tc_ematch/tc_em_nbyte.h>
  15#include <net/pkt_cls.h>
  16
  17struct nbyte_data {
  18        struct tcf_em_nbyte     hdr;
  19        char                    pattern[0];
  20};
  21
  22static int em_nbyte_change(struct net *net, void *data, int data_len,
  23                           struct tcf_ematch *em)
  24{
  25        struct tcf_em_nbyte *nbyte = data;
  26
  27        if (data_len < sizeof(*nbyte) ||
  28            data_len < (sizeof(*nbyte) + nbyte->len))
  29                return -EINVAL;
  30
  31        em->datalen = sizeof(*nbyte) + nbyte->len;
  32        em->data = (unsigned long)kmemdup(data, em->datalen, GFP_KERNEL);
  33        if (em->data == 0UL)
  34                return -ENOBUFS;
  35
  36        return 0;
  37}
  38
  39static int em_nbyte_match(struct sk_buff *skb, struct tcf_ematch *em,
  40                          struct tcf_pkt_info *info)
  41{
  42        struct nbyte_data *nbyte = (struct nbyte_data *) em->data;
  43        unsigned char *ptr = tcf_get_base_ptr(skb, nbyte->hdr.layer);
  44
  45        ptr += nbyte->hdr.off;
  46
  47        if (!tcf_valid_offset(skb, ptr, nbyte->hdr.len))
  48                return 0;
  49
  50        return !memcmp(ptr, nbyte->pattern, nbyte->hdr.len);
  51}
  52
  53static struct tcf_ematch_ops em_nbyte_ops = {
  54        .kind     = TCF_EM_NBYTE,
  55        .change   = em_nbyte_change,
  56        .match    = em_nbyte_match,
  57        .owner    = THIS_MODULE,
  58        .link     = LIST_HEAD_INIT(em_nbyte_ops.link)
  59};
  60
  61static int __init init_em_nbyte(void)
  62{
  63        return tcf_em_register(&em_nbyte_ops);
  64}
  65
  66static void __exit exit_em_nbyte(void)
  67{
  68        tcf_em_unregister(&em_nbyte_ops);
  69}
  70
  71MODULE_LICENSE("GPL");
  72
  73module_init(init_em_nbyte);
  74module_exit(exit_em_nbyte);
  75
  76MODULE_ALIAS_TCF_EMATCH(TCF_EM_NBYTE);
  77