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 22struct text_match 23{ 24 u16 from_offset; 25 u16 to_offset; 26 u8 from_layer; 27 u8 to_layer; 28 struct ts_config *config; 29}; 30 31#define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data) 32 33static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m, 34 struct tcf_pkt_info *info) 35{ 36 struct text_match *tm = EM_TEXT_PRIV(m); 37 int from, to; 38 struct ts_state state; 39 40 from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data; 41 from += tm->from_offset; 42 43 to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data; 44 to += tm->to_offset; 45 46 return skb_find_text(skb, from, to, tm->config, &state) != UINT_MAX; 47} 48 49static int em_text_change(struct tcf_proto *tp, void *data, int len, 50 struct tcf_ematch *m) 51{ 52 struct text_match *tm; 53 struct tcf_em_text *conf = data; 54 struct ts_config *ts_conf; 55 int flags = 0; 56 57 if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len)) 58 return -EINVAL; 59 60 if (conf->from_layer > conf->to_layer) 61 return -EINVAL; 62 63 if (conf->from_layer == conf->to_layer && 64 conf->from_offset > conf->to_offset) 65 return -EINVAL; 66 67retry: 68 ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf), 69 conf->pattern_len, GFP_KERNEL, flags); 70 71 if (flags & TS_AUTOLOAD) 72 rtnl_lock(); 73 74 if (IS_ERR(ts_conf)) { 75 if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) { 76 rtnl_unlock(); 77 flags |= TS_AUTOLOAD; 78 goto retry; 79 } else 80 return PTR_ERR(ts_conf); 81 } else if (flags & TS_AUTOLOAD) { 82 textsearch_destroy(ts_conf); 83 return -EAGAIN; 84 } 85 86 tm = kmalloc(sizeof(*tm), GFP_KERNEL); 87 if (tm == NULL) { 88 textsearch_destroy(ts_conf); 89 return -ENOBUFS; 90 } 91 92 tm->from_offset = conf->from_offset; 93 tm->to_offset = conf->to_offset; 94 tm->from_layer = conf->from_layer; 95 tm->to_layer = conf->to_layer; 96 tm->config = ts_conf; 97 98 m->datalen = sizeof(*tm); 99 m->data = (unsigned long) tm; 100 101 return 0; 102} 103 104static void em_text_destroy(struct tcf_proto *tp, struct tcf_ematch *m) 105{ 106 textsearch_destroy(EM_TEXT_PRIV(m)->config); 107} 108 109static 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 129nla_put_failure: 130 return -1; 131} 132 133static 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 143static int __init init_em_text(void) 144{ 145 return tcf_em_register(&em_text_ops); 146} 147 148static void __exit exit_em_text(void) 149{ 150 tcf_em_unregister(&em_text_ops); 151} 152 153MODULE_LICENSE("GPL"); 154 155module_init(init_em_text); 156module_exit(exit_em_text); 157 158MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT); 159