em_text.c
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/*
* net/sched/em_text.c Textsearch 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/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/skbuff.h>
#include <linux/textsearch.h>
#include <linux/tc_ematch/tc_em_text.h>
#include <net/pkt_cls.h>
struct text_match
{
u16 from_offset;
u16 to_offset;
u8 from_layer;
u8 to_layer;
struct ts_config *config;
};
#define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data)
static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m,
struct tcf_pkt_info *info)
{
struct text_match *tm = EM_TEXT_PRIV(m);
int from, to;
struct ts_state state;
from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data;
from += tm->from_offset;
to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data;
to += tm->to_offset;
return skb_find_text(skb, from, to, tm->config, &state) != UINT_MAX;
}
static int em_text_change(struct tcf_proto *tp, void *data, int len,
struct tcf_ematch *m)
{
struct text_match *tm;
struct tcf_em_text *conf = data;
struct ts_config *ts_conf;
int flags = 0;
if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len))
return -EINVAL;
if (conf->from_layer > conf->to_layer)
return -EINVAL;
if (conf->from_layer == conf->to_layer &&
conf->from_offset > conf->to_offset)
return -EINVAL;
retry:
ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf),
conf->pattern_len, GFP_KERNEL, flags);
if (flags & TS_AUTOLOAD)
rtnl_lock();
if (IS_ERR(ts_conf)) {
if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) {
rtnl_unlock();
flags |= TS_AUTOLOAD;
goto retry;
} else
return PTR_ERR(ts_conf);
} else if (flags & TS_AUTOLOAD) {
textsearch_destroy(ts_conf);
return -EAGAIN;
}
tm = kmalloc(sizeof(*tm), GFP_KERNEL);
if (tm == NULL) {
textsearch_destroy(ts_conf);
return -ENOBUFS;
}
tm->from_offset = conf->from_offset;
tm->to_offset = conf->to_offset;
tm->from_layer = conf->from_layer;
tm->to_layer = conf->to_layer;
tm->config = ts_conf;
m->datalen = sizeof(*tm);
m->data = (unsigned long) tm;
return 0;
}
static void em_text_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
{
textsearch_destroy(EM_TEXT_PRIV(m)->config);
}
static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m)
{
struct text_match *tm = EM_TEXT_PRIV(m);
struct tcf_em_text conf;
strncpy(conf.algo, tm->config->ops->name, sizeof(conf.algo) - 1);
conf.from_offset = tm->from_offset;
conf.to_offset = tm->to_offset;
conf.from_layer = tm->from_layer;
conf.to_layer = tm->to_layer;
conf.pattern_len = textsearch_get_pattern_len(tm->config);
conf.pad = 0;
if (nla_put_nohdr(skb, sizeof(conf), &conf) < 0)
goto nla_put_failure;
if (nla_append(skb, conf.pattern_len,
textsearch_get_pattern(tm->config)) < 0)
goto nla_put_failure;
return 0;
nla_put_failure:
return -1;
}
static struct tcf_ematch_ops em_text_ops = {
.kind = TCF_EM_TEXT,
.change = em_text_change,
.match = em_text_match,
.destroy = em_text_destroy,
.dump = em_text_dump,
.owner = THIS_MODULE,
.link = LIST_HEAD_INIT(em_text_ops.link)
};
static int __init init_em_text(void)
{
return tcf_em_register(&em_text_ops);
}
static void __exit exit_em_text(void)
{
tcf_em_unregister(&em_text_ops);
}
MODULE_LICENSE("GPL");
module_init(init_em_text);
module_exit(exit_em_text);
MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT);