1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * net/sched/em_nbyte.c N-Byte ematch 4 * 5 * Authors: Thomas Graf <tgraf@suug.ch> 6 */ 7 8 #include <linux/gfp.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/tc_ematch/tc_em_nbyte.h> 15 #include <net/pkt_cls.h> 16 17 struct nbyte_data { 18 struct tcf_em_nbyte hdr; 19 char pattern[]; 20 }; 21 22 static int em_nbyte_change(struct net *net, void *data, int data_len, 23 struct tcf_ematch *em) 24 { 25 struct tcf_em_nbyte *nbyte = data; 26 27 if (data_len < sizeof(*nbyte) || 28 data_len < (sizeof(*nbyte) + nbyte->len)) 29 return -EINVAL; 30 31 em->datalen = sizeof(*nbyte) + nbyte->len; 32 em->data = (unsigned long)kmemdup(data, em->datalen, GFP_KERNEL); 33 if (em->data == 0UL) 34 return -ENOMEM; 35 36 return 0; 37 } 38 39 static int em_nbyte_match(struct sk_buff *skb, struct tcf_ematch *em, 40 struct tcf_pkt_info *info) 41 { 42 struct nbyte_data *nbyte = (struct nbyte_data *) em->data; 43 unsigned char *ptr = tcf_get_base_ptr(skb, nbyte->hdr.layer); 44 45 ptr += nbyte->hdr.off; 46 47 if (!tcf_valid_offset(skb, ptr, nbyte->hdr.len)) 48 return 0; 49 50 return !memcmp(ptr, nbyte->pattern, nbyte->hdr.len); 51 } 52 53 static struct tcf_ematch_ops em_nbyte_ops = { 54 .kind = TCF_EM_NBYTE, 55 .change = em_nbyte_change, 56 .match = em_nbyte_match, 57 .owner = THIS_MODULE, 58 .link = LIST_HEAD_INIT(em_nbyte_ops.link) 59 }; 60 61 static int __init init_em_nbyte(void) 62 { 63 return tcf_em_register(&em_nbyte_ops); 64 } 65 66 static void __exit exit_em_nbyte(void) 67 { 68 tcf_em_unregister(&em_nbyte_ops); 69 } 70 71 MODULE_DESCRIPTION("ematch classifier for arbitrary skb multi-bytes"); 72 MODULE_LICENSE("GPL"); 73 74 module_init(init_em_nbyte); 75 module_exit(exit_em_nbyte); 76 77 MODULE_ALIAS_TCF_EMATCH(TCF_EM_NBYTE); 78