root/net/sched/em_text.c

DEFINITIONS

1. em_text_match
2. em_text_change
3. em_text_destroy
4. em_text_dump
5. init_em_text
6. exit_em_text

/*
 * 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);