1 /* 2 * net/sched/em_text.c Textsearch ematch 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Thomas Graf <tgraf@suug.ch> 10 */ 11 12 #include <linux/slab.h> 13 #include <linux/module.h> 14 #include <linux/types.h> 15 #include <linux/kernel.h> 16 #include <linux/string.h> 17 #include <linux/skbuff.h> 18 #include <linux/textsearch.h> 19 #include <linux/tc_ematch/tc_em_text.h> 20 #include <net/pkt_cls.h> 21 22 struct text_match { 23 u16 from_offset; 24 u16 to_offset; 25 u8 from_layer; 26 u8 to_layer; 27 struct ts_config *config; 28 }; 29 30 #define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data) 31 32 static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m, 33 struct tcf_pkt_info *info) 34 { 35 struct text_match *tm = EM_TEXT_PRIV(m); 36 int from, to; 37 struct ts_state state; 38 39 from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data; 40 from += tm->from_offset; 41 42 to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data; 43 to += tm->to_offset; 44 45 return skb_find_text(skb, from, to, tm->config, &state) != UINT_MAX; 46 } 47 48 static int em_text_change(struct net *net, void *data, int len, 49 struct tcf_ematch *m) 50 { 51 struct text_match *tm; 52 struct tcf_em_text *conf = data; 53 struct ts_config *ts_conf; 54 int flags = 0; 55 56 if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len)) 57 return -EINVAL; 58 59 if (conf->from_layer > conf->to_layer) 60 return -EINVAL; 61 62 if (conf->from_layer == conf->to_layer && 63 conf->from_offset > conf->to_offset) 64 return -EINVAL; 65 66 retry: 67 ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf), 68 conf->pattern_len, GFP_KERNEL, flags); 69 70 if (flags & TS_AUTOLOAD) 71 rtnl_lock(); 72 73 if (IS_ERR(ts_conf)) { 74 if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) { 75 rtnl_unlock(); 76 flags |= TS_AUTOLOAD; 77 goto retry; 78 } else 79 return PTR_ERR(ts_conf); 80 } else if (flags & TS_AUTOLOAD) { 81 textsearch_destroy(ts_conf); 82 return -EAGAIN; 83 } 84 85 tm = kmalloc(sizeof(*tm), GFP_KERNEL); 86 if (tm == NULL) { 87 textsearch_destroy(ts_conf); 88 return -ENOBUFS; 89 } 90 91 tm->from_offset = conf->from_offset; 92 tm->to_offset = conf->to_offset; 93 tm->from_layer = conf->from_layer; 94 tm->to_layer = conf->to_layer; 95 tm->config = ts_conf; 96 97 m->datalen = sizeof(*tm); 98 m->data = (unsigned long) tm; 99 100 return 0; 101 } 102 103 static void em_text_destroy(struct tcf_ematch *m) 104 { 105 if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config) 106 textsearch_destroy(EM_TEXT_PRIV(m)->config); 107 } 108 109 static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m) 110 { 111 struct text_match *tm = EM_TEXT_PRIV(m); 112 struct tcf_em_text conf; 113 114 strncpy(conf.algo, tm->config->ops->name, sizeof(conf.algo) - 1); 115 conf.from_offset = tm->from_offset; 116 conf.to_offset = tm->to_offset; 117 conf.from_layer = tm->from_layer; 118 conf.to_layer = tm->to_layer; 119 conf.pattern_len = textsearch_get_pattern_len(tm->config); 120 conf.pad = 0; 121 122 if (nla_put_nohdr(skb, sizeof(conf), &conf) < 0) 123 goto nla_put_failure; 124 if (nla_append(skb, conf.pattern_len, 125 textsearch_get_pattern(tm->config)) < 0) 126 goto nla_put_failure; 127 return 0; 128 129 nla_put_failure: 130 return -1; 131 } 132 133 static struct tcf_ematch_ops em_text_ops = { 134 .kind = TCF_EM_TEXT, 135 .change = em_text_change, 136 .match = em_text_match, 137 .destroy = em_text_destroy, 138 .dump = em_text_dump, 139 .owner = THIS_MODULE, 140 .link = LIST_HEAD_INIT(em_text_ops.link) 141 }; 142 143 static int __init init_em_text(void) 144 { 145 return tcf_em_register(&em_text_ops); 146 } 147 148 static void __exit exit_em_text(void) 149 { 150 tcf_em_unregister(&em_text_ops); 151 } 152 153 MODULE_LICENSE("GPL"); 154 155 module_init(init_em_text); 156 module_exit(exit_em_text); 157 158 MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT); 159