1 /* 2 * net/sched/em_nbyte.c N-Byte 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/gfp.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/tc_ematch/tc_em_nbyte.h> 19 #include <net/pkt_cls.h> 20 21 struct nbyte_data 22 { 23 struct tcf_em_nbyte hdr; 24 char pattern[0]; 25 }; 26 27 static int em_nbyte_change(struct tcf_proto *tp, void *data, int data_len, 28 struct tcf_ematch *em) 29 { 30 struct tcf_em_nbyte *nbyte = data; 31 32 if (data_len < sizeof(*nbyte) || 33 data_len < (sizeof(*nbyte) + nbyte->len)) 34 return -EINVAL; 35 36 em->datalen = sizeof(*nbyte) + nbyte->len; 37 em->data = (unsigned long)kmemdup(data, em->datalen, GFP_KERNEL); 38 if (em->data == 0UL) 39 return -ENOBUFS; 40 41 return 0; 42 } 43 44 static int em_nbyte_match(struct sk_buff *skb, struct tcf_ematch *em, 45 struct tcf_pkt_info *info) 46 { 47 struct nbyte_data *nbyte = (struct nbyte_data *) em->data; 48 unsigned char *ptr = tcf_get_base_ptr(skb, nbyte->hdr.layer); 49 50 ptr += nbyte->hdr.off; 51 52 if (!tcf_valid_offset(skb, ptr, nbyte->hdr.len)) 53 return 0; 54 55 return !memcmp(ptr + nbyte->hdr.off, nbyte->pattern, nbyte->hdr.len); 56 } 57 58 static struct tcf_ematch_ops em_nbyte_ops = { 59 .kind = TCF_EM_NBYTE, 60 .change = em_nbyte_change, 61 .match = em_nbyte_match, 62 .owner = THIS_MODULE, 63 .link = LIST_HEAD_INIT(em_nbyte_ops.link) 64 }; 65 66 static int __init init_em_nbyte(void) 67 { 68 return tcf_em_register(&em_nbyte_ops); 69 } 70 71 static void __exit exit_em_nbyte(void) 72 { 73 tcf_em_unregister(&em_nbyte_ops); 74 } 75 76 MODULE_LICENSE("GPL"); 77 78 module_init(init_em_nbyte); 79 module_exit(exit_em_nbyte); 80 81 MODULE_ALIAS_TCF_EMATCH(TCF_EM_NBYTE); 82