Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* IP tables module for matching the value of the IPv4 DSCP field |
| 2 | * |
| 3 | * ipt_dscp.c,v 1.3 2002/08/05 19:00:21 laforge Exp |
| 4 | * |
| 5 | * (C) 2002 by Harald Welte <laforge@netfilter.org> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/skbuff.h> |
| 14 | |
| 15 | #include <linux/netfilter_ipv4/ipt_dscp.h> |
| 16 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 17 | |
| 18 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); |
| 19 | MODULE_DESCRIPTION("iptables DSCP matching module"); |
| 20 | MODULE_LICENSE("GPL"); |
| 21 | |
| 22 | static int match(const struct sk_buff *skb, const struct net_device *in, |
| 23 | const struct net_device *out, const void *matchinfo, |
| 24 | int offset, int *hotdrop) |
| 25 | { |
| 26 | const struct ipt_dscp_info *info = matchinfo; |
| 27 | const struct iphdr *iph = skb->nh.iph; |
| 28 | |
| 29 | u_int8_t sh_dscp = ((info->dscp << IPT_DSCP_SHIFT) & IPT_DSCP_MASK); |
| 30 | |
| 31 | return ((iph->tos&IPT_DSCP_MASK) == sh_dscp) ^ info->invert; |
| 32 | } |
| 33 | |
| 34 | static int checkentry(const char *tablename, const struct ipt_ip *ip, |
| 35 | void *matchinfo, unsigned int matchsize, |
| 36 | unsigned int hook_mask) |
| 37 | { |
| 38 | if (matchsize != IPT_ALIGN(sizeof(struct ipt_dscp_info))) |
| 39 | return 0; |
| 40 | |
| 41 | return 1; |
| 42 | } |
| 43 | |
| 44 | static struct ipt_match dscp_match = { |
| 45 | .name = "dscp", |
| 46 | .match = &match, |
| 47 | .checkentry = &checkentry, |
| 48 | .me = THIS_MODULE, |
| 49 | }; |
| 50 | |
| 51 | static int __init init(void) |
| 52 | { |
| 53 | return ipt_register_match(&dscp_match); |
| 54 | } |
| 55 | |
| 56 | static void __exit fini(void) |
| 57 | { |
| 58 | ipt_unregister_match(&dscp_match); |
| 59 | |
| 60 | } |
| 61 | |
| 62 | module_init(init); |
| 63 | module_exit(fini); |