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 38 from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data; 39 from += tm->from_offset; 40 41 to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data; 42 to += tm->to_offset; 43 44 return skb_find_text(skb, from, to, tm->config) != UINT_MAX; 45 } 46 47 static int em_text_change(struct net *net, void *data, int len, 48 struct tcf_ematch *m) 49 { 50 struct text_match *tm; 51 struct tcf_em_text *conf = data; 52 struct ts_config *ts_conf; 53 int flags = 0; 54 55 if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len)) 56 return -EINVAL; 57 58 if (conf->from_layer > conf->to_layer) 59 return -EINVAL; 60 61 if (conf->from_layer == conf->to_layer && 62 conf->from_offset > conf->to_offset) 63 return -EINVAL; 64 65 retry: 66 ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf), 67 conf->pattern_len, GFP_KERNEL, flags); 68 69 if (flags & TS_AUTOLOAD) 70 rtnl_lock(); 71 72 if (IS_ERR(ts_conf)) { 73 if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) { 74 rtnl_unlock(); 75 flags |= TS_AUTOLOAD; 76 goto retry; 77 } else 78 return PTR_ERR(ts_conf); 79 } else if (flags & TS_AUTOLOAD) { 80 textsearch_destroy(ts_conf); 81 return -EAGAIN; 82 } 83 84 tm = kmalloc(sizeof(*tm), GFP_KERNEL); 85 if (tm == NULL) { 86 textsearch_destroy(ts_conf); 87 return -ENOBUFS; 88 } 89 90 tm->from_offset = conf->from_offset; 91 tm->to_offset = conf->to_offset; 92 tm->from_layer = conf->from_layer; 93 tm->to_layer = conf->to_layer; 94 tm->config = ts_conf; 95 96 m->datalen = sizeof(*tm); 97 m->data = (unsigned long) tm; 98 99 return 0; 100 } 101 102 static void em_text_destroy(struct tcf_ematch *m) 103 { 104 if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config) 105 textsearch_destroy(EM_TEXT_PRIV(m)->config); 106 } 107 108 static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m) 109 { 110 struct text_match *tm = EM_TEXT_PRIV(m); 111 struct tcf_em_text conf; 112 113 strncpy(conf.algo, tm->config->ops->name, sizeof(conf.algo) - 1); 114 conf.from_offset = tm->from_offset; 115 conf.to_offset = tm->to_offset; 116 conf.from_layer = tm->from_layer; 117 conf.to_layer = tm->to_layer; 118 conf.pattern_len = textsearch_get_pattern_len(tm->config); 119 conf.pad = 0; 120 121 if (nla_put_nohdr(skb, sizeof(conf), &conf) < 0) 122 goto nla_put_failure; 123 if (nla_append(skb, conf.pattern_len, 124 textsearch_get_pattern(tm->config)) < 0) 125 goto nla_put_failure; 126 return 0; 127 128 nla_put_failure: 129 return -1; 130 } 131 132 static struct tcf_ematch_ops em_text_ops = { 133 .kind = TCF_EM_TEXT, 134 .change = em_text_change, 135 .match = em_text_match, 136 .destroy = em_text_destroy, 137 .dump = em_text_dump, 138 .owner = THIS_MODULE, 139 .link = LIST_HEAD_INIT(em_text_ops.link) 140 }; 141 142 static int __init init_em_text(void) 143 { 144 return tcf_em_register(&em_text_ops); 145 } 146 147 static void __exit exit_em_text(void) 148 { 149 tcf_em_unregister(&em_text_ops); 150 } 151 152 MODULE_LICENSE("GPL"); 153 154 module_init(init_em_text); 155 module_exit(exit_em_text); 156 157 MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT); 158