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 kfree(EM_TEXT_PRIV(m)); 103 } 104 } 105 106 static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m) 107 { 108 struct text_match *tm = EM_TEXT_PRIV(m); 109 struct tcf_em_text conf; 110 111 strncpy(conf.algo, tm->config->ops->name, sizeof(conf.algo) - 1); 112 conf.from_offset = tm->from_offset; 113 conf.to_offset = tm->to_offset; 114 conf.from_layer = tm->from_layer; 115 conf.to_layer = tm->to_layer; 116 conf.pattern_len = textsearch_get_pattern_len(tm->config); 117 conf.pad = 0; 118 119 if (nla_put_nohdr(skb, sizeof(conf), &conf) < 0) 120 goto nla_put_failure; 121 if (nla_append(skb, conf.pattern_len, 122 textsearch_get_pattern(tm->config)) < 0) 123 goto nla_put_failure; 124 return 0; 125 126 nla_put_failure: 127 return -1; 128 } 129 130 static struct tcf_ematch_ops em_text_ops = { 131 .kind = TCF_EM_TEXT, 132 .change = em_text_change, 133 .match = em_text_match, 134 .destroy = em_text_destroy, 135 .dump = em_text_dump, 136 .owner = THIS_MODULE, 137 .link = LIST_HEAD_INIT(em_text_ops.link) 138 }; 139 140 static int __init init_em_text(void) 141 { 142 return tcf_em_register(&em_text_ops); 143 } 144 145 static void __exit exit_em_text(void) 146 { 147 tcf_em_unregister(&em_text_ops); 148 } 149 150 MODULE_DESCRIPTION("ematch classifier for embedded text in skbs"); 151 MODULE_LICENSE("GPL"); 152 153 module_init(init_em_text); 154 module_exit(exit_em_text); 155 156 MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT); 157