em_nbyte.c
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/*
* net/sched/em_nbyte.c N-Byte ematch
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Authors: Thomas Graf <tgraf@suug.ch>
*/
#include <linux/gfp.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/tc_ematch/tc_em_nbyte.h>
#include <net/pkt_cls.h>
struct nbyte_data {
struct tcf_em_nbyte hdr;
char pattern[0];
};
static int em_nbyte_change(struct tcf_proto *tp, void *data, int data_len,
struct tcf_ematch *em)
{
struct tcf_em_nbyte *nbyte = data;
if (data_len < sizeof(*nbyte) ||
data_len < (sizeof(*nbyte) + nbyte->len))
return -EINVAL;
em->datalen = sizeof(*nbyte) + nbyte->len;
em->data = (unsigned long)kmemdup(data, em->datalen, GFP_KERNEL);
if (em->data == 0UL)
return -ENOBUFS;
return 0;
}
static int em_nbyte_match(struct sk_buff *skb, struct tcf_ematch *em,
struct tcf_pkt_info *info)
{
struct nbyte_data *nbyte = (struct nbyte_data *) em->data;
unsigned char *ptr = tcf_get_base_ptr(skb, nbyte->hdr.layer);
ptr += nbyte->hdr.off;
if (!tcf_valid_offset(skb, ptr, nbyte->hdr.len))
return 0;
return !memcmp(ptr + nbyte->hdr.off, nbyte->pattern, nbyte->hdr.len);
}
static struct tcf_ematch_ops em_nbyte_ops = {
.kind = TCF_EM_NBYTE,
.change = em_nbyte_change,
.match = em_nbyte_match,
.owner = THIS_MODULE,
.link = LIST_HEAD_INIT(em_nbyte_ops.link)
};
static int __init init_em_nbyte(void)
{
return tcf_em_register(&em_nbyte_ops);
}
static void __exit exit_em_nbyte(void)
{
tcf_em_unregister(&em_nbyte_ops);
}
MODULE_LICENSE("GPL");
module_init(init_em_nbyte);
module_exit(exit_em_nbyte);
MODULE_ALIAS_TCF_EMATCH(TCF_EM_NBYTE);