linux/net/sched/em_text.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * net/sched/em_text.c  Textsearch ematch
   4 *
   5 * Authors:     Thomas Graf <tgraf@suug.ch>
   6 */
   7
   8#include <linux/slab.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/textsearch.h>
  15#include <linux/tc_ematch/tc_em_text.h>
  16#include <net/pkt_cls.h>
  17
  18struct text_match {
  19        u16                     from_offset;
  20        u16                     to_offset;
  21        u8                      from_layer;
  22        u8                      to_layer;
  23        struct ts_config        *config;
  24};
  25
  26#define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data)
  27
  28static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m,
  29                         struct tcf_pkt_info *info)
  30{
  31        struct text_match *tm = EM_TEXT_PRIV(m);
  32        int from, to;
  33
  34        from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data;
  35        from += tm->from_offset;
  36
  37        to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data;
  38        to += tm->to_offset;
  39
  40        return skb_find_text(skb, from, to, tm->config) != UINT_MAX;
  41}
  42
  43static int em_text_change(struct net *net, void *data, int len,
  44                          struct tcf_ematch *m)
  45{
  46        struct text_match *tm;
  47        struct tcf_em_text *conf = data;
  48        struct ts_config *ts_conf;
  49        int flags = 0;
  50
  51        if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len))
  52                return -EINVAL;
  53
  54        if (conf->from_layer > conf->to_layer)
  55                return -EINVAL;
  56
  57        if (conf->from_layer == conf->to_layer &&
  58            conf->from_offset > conf->to_offset)
  59                return -EINVAL;
  60
  61retry:
  62        ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf),
  63                                     conf->pattern_len, GFP_KERNEL, flags);
  64
  65        if (flags & TS_AUTOLOAD)
  66                rtnl_lock();
  67
  68        if (IS_ERR(ts_conf)) {
  69                if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) {
  70                        rtnl_unlock();
  71                        flags |= TS_AUTOLOAD;
  72                        goto retry;
  73                } else
  74                        return PTR_ERR(ts_conf);
  75        } else if (flags & TS_AUTOLOAD) {
  76                textsearch_destroy(ts_conf);
  77                return -EAGAIN;
  78        }
  79
  80        tm = kmalloc(sizeof(*tm), GFP_KERNEL);
  81        if (tm == NULL) {
  82                textsearch_destroy(ts_conf);
  83                return -ENOBUFS;
  84        }
  85
  86        tm->from_offset = conf->from_offset;
  87        tm->to_offset   = conf->to_offset;
  88        tm->from_layer  = conf->from_layer;
  89        tm->to_layer    = conf->to_layer;
  90        tm->config      = ts_conf;
  91
  92        m->datalen = sizeof(*tm);
  93        m->data = (unsigned long) tm;
  94
  95        return 0;
  96}
  97
  98static void em_text_destroy(struct tcf_ematch *m)
  99{
 100        if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config)
 101                textsearch_destroy(EM_TEXT_PRIV(m)->config);
 102}
 103
 104static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m)
 105{
 106        struct text_match *tm = EM_TEXT_PRIV(m);
 107        struct tcf_em_text conf;
 108
 109        strncpy(conf.algo, tm->config->ops->name, sizeof(conf.algo) - 1);
 110        conf.from_offset = tm->from_offset;
 111        conf.to_offset = tm->to_offset;
 112        conf.from_layer = tm->from_layer;
 113        conf.to_layer = tm->to_layer;
 114        conf.pattern_len = textsearch_get_pattern_len(tm->config);
 115        conf.pad = 0;
 116
 117        if (nla_put_nohdr(skb, sizeof(conf), &conf) < 0)
 118                goto nla_put_failure;
 119        if (nla_append(skb, conf.pattern_len,
 120                       textsearch_get_pattern(tm->config)) < 0)
 121                goto nla_put_failure;
 122        return 0;
 123
 124nla_put_failure:
 125        return -1;
 126}
 127
 128static struct tcf_ematch_ops em_text_ops = {
 129        .kind     = TCF_EM_TEXT,
 130        .change   = em_text_change,
 131        .match    = em_text_match,
 132        .destroy  = em_text_destroy,
 133        .dump     = em_text_dump,
 134        .owner    = THIS_MODULE,
 135        .link     = LIST_HEAD_INIT(em_text_ops.link)
 136};
 137
 138static int __init init_em_text(void)
 139{
 140        return tcf_em_register(&em_text_ops);
 141}
 142
 143static void __exit exit_em_text(void)
 144{
 145        tcf_em_unregister(&em_text_ops);
 146}
 147
 148MODULE_LICENSE("GPL");
 149
 150module_init(init_em_text);
 151module_exit(exit_em_text);
 152
 153MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT);
 154