net/sched/em_text.c

   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
  18 struct 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
  28 static 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
  43 static 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
  61 retry:
  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
  98 static 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
 104 static 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
 124 nla_put_failure:
 125         return -1;
 126 }
 127
 128 static 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
 138 static int __init init_em_text(void)
 139 {
 140         return tcf_em_register(&em_text_ops);
 141 }
 142
 143 static void __exit exit_em_text(void)
 144 {
 145         tcf_em_unregister(&em_text_ops);
 146 }
 147
 148 MODULE_LICENSE("GPL");
 149
 150 module_init(init_em_text);
 151 module_exit(exit_em_text);
 152
 153 MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT);