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 unsigned char *ptr; 33 int from, to; 34 35 ptr = tcf_get_base_ptr(skb, tm->from_layer); 36 if (!ptr) 37 return 0; 38 from = ptr - skb->data; 39 from += tm->from_offset; 40 41 ptr = tcf_get_base_ptr(skb, tm->to_layer); 42 if (!ptr) 43 return 0; 44 to = ptr - skb->data; 45 to += tm->to_offset; 46 47 return skb_find_text(skb, from, to, tm->config) != UINT_MAX; 48 } 49 50 static int em_text_change(struct net *net, void *data, int len, 51 struct tcf_ematch *m) 52 { 53 struct text_match *tm; 54 struct tcf_em_text *conf = data; 55 struct ts_config *ts_conf; 56 int flags = 0; 57 58 if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len)) 59 return -EINVAL; 60 61 if (!memchr(conf->algo, '\0', sizeof(conf->algo))) 62 return -EINVAL; 63 64 if (conf->from_layer > conf->to_layer) 65 return -EINVAL; 66 67 if (conf->from_layer == conf->to_layer && 68 conf->from_offset > conf->to_offset) 69 return -EINVAL; 70 71 retry: 72 ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf), 73 conf->pattern_len, GFP_KERNEL, flags); 74 75 if (flags & TS_AUTOLOAD) 76 rtnl_lock(); 77 78 if (IS_ERR(ts_conf)) { 79 if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) { 80 rtnl_unlock(); 81 flags |= TS_AUTOLOAD; 82 goto retry; 83 } else 84 return PTR_ERR(ts_conf); 85 } else if (flags & TS_AUTOLOAD) { 86 textsearch_destroy(ts_conf); 87 return -EAGAIN; 88 } 89 90 tm = kmalloc_obj(*tm); 91 if (tm == NULL) { 92 textsearch_destroy(ts_conf); 93 return -ENOBUFS; 94 } 95 96 tm->from_offset = conf->from_offset; 97 tm->to_offset = conf->to_offset; 98 tm->from_layer = conf->from_layer; 99 tm->to_layer = conf->to_layer; 100 tm->config = ts_conf; 101 102 m->datalen = sizeof(*tm); 103 m->data = (unsigned long) tm; 104 105 return 0; 106 } 107 108 static void em_text_destroy(struct tcf_ematch *m) 109 { 110 if (EM_TEXT_PRIV(m) && EM_TEXT_PRIV(m)->config) { 111 textsearch_destroy(EM_TEXT_PRIV(m)->config); 112 kfree(EM_TEXT_PRIV(m)); 113 } 114 } 115 116 static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m) 117 { 118 struct text_match *tm = EM_TEXT_PRIV(m); 119 struct tcf_em_text conf = {}; 120 121 strscpy(conf.algo, tm->config->ops->name); 122 conf.from_offset = tm->from_offset; 123 conf.to_offset = tm->to_offset; 124 conf.from_layer = tm->from_layer; 125 conf.to_layer = tm->to_layer; 126 conf.pattern_len = textsearch_get_pattern_len(tm->config); 127 conf.pad = 0; 128 129 if (nla_put_nohdr(skb, sizeof(conf), &conf) < 0) 130 goto nla_put_failure; 131 if (nla_append(skb, conf.pattern_len, 132 textsearch_get_pattern(tm->config)) < 0) 133 goto nla_put_failure; 134 return 0; 135 136 nla_put_failure: 137 return -1; 138 } 139 140 static struct tcf_ematch_ops em_text_ops = { 141 .kind = TCF_EM_TEXT, 142 .change = em_text_change, 143 .match = em_text_match, 144 .destroy = em_text_destroy, 145 .dump = em_text_dump, 146 .owner = THIS_MODULE, 147 .link = LIST_HEAD_INIT(em_text_ops.link) 148 }; 149 150 static int __init init_em_text(void) 151 { 152 return tcf_em_register(&em_text_ops); 153 } 154 155 static void __exit exit_em_text(void) 156 { 157 tcf_em_unregister(&em_text_ops); 158 } 159 160 MODULE_DESCRIPTION("ematch classifier for embedded text in skbs"); 161 MODULE_LICENSE("GPL"); 162 163 module_init(init_em_text); 164 module_exit(exit_em_text); 165 166 MODULE_ALIAS_TCF_EMATCH(TCF_EM_TEXT); 167