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/config.h> 13 #include <linux/module.h> 14 #include <linux/types.h> 15 #include <linux/kernel.h> 16 #include <linux/sched.h> 17 #include <linux/string.h> 18 #include <linux/skbuff.h> 19 #include <linux/tc_ematch/tc_em_nbyte.h> 20 #include <net/pkt_cls.h> 21 22 struct nbyte_data 23 { 24 struct tcf_em_nbyte hdr; 25 char pattern[0]; 26 }; 27 28 static int em_nbyte_change(struct tcf_proto *tp, void *data, int data_len, 29 struct tcf_ematch *em) 30 { 31 struct tcf_em_nbyte *nbyte = data; 32 33 if (data_len < sizeof(*nbyte) || 34 data_len < (sizeof(*nbyte) + nbyte->len)) 35 return -EINVAL; 36 37 em->datalen = sizeof(*nbyte) + nbyte->len; 38 em->data = (unsigned long) kmalloc(em->datalen, GFP_KERNEL); 39 if (em->data == 0UL) 40 return -ENOBUFS; 41 42 memcpy((void *) em->data, data, em->datalen); 43 44 return 0; 45 } 46 47 static int em_nbyte_match(struct sk_buff *skb, struct tcf_ematch *em, 48 struct tcf_pkt_info *info) 49 { 50 struct nbyte_data *nbyte = (struct nbyte_data *) em->data; 51 unsigned char *ptr = tcf_get_base_ptr(skb, nbyte->hdr.layer); 52 53 ptr += nbyte->hdr.off; 54 55 if (!tcf_valid_offset(skb, ptr, nbyte->hdr.len)) 56 return 0; 57 58 return !memcmp(ptr + nbyte->hdr.off, nbyte->pattern, nbyte->hdr.len); 59 } 60 61 static struct tcf_ematch_ops em_nbyte_ops = { 62 .kind = TCF_EM_NBYTE, 63 .change = em_nbyte_change, 64 .match = em_nbyte_match, 65 .owner = THIS_MODULE, 66 .link = LIST_HEAD_INIT(em_nbyte_ops.link) 67 }; 68 69 static int __init init_em_nbyte(void) 70 { 71 return tcf_em_register(&em_nbyte_ops); 72 } 73 74 static void __exit exit_em_nbyte(void) 75 { 76 tcf_em_unregister(&em_nbyte_ops); 77 } 78 79 MODULE_LICENSE("GPL"); 80 81 module_init(init_em_nbyte); 82 module_exit(exit_em_nbyte); 83