projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| e905a9ed | 1 | /* IP tables module for matching the value of the TTL |
| 1da177e4 LT |
2 | * |
| 3 | * (C) 2000,2001 by Harald Welte <laforge@netfilter.org> | |
| 4 | * | |
| 5 | * This program is free software; you can redistribute it and/or modify | |
| 6 | * it under the terms of the GNU General Public License version 2 as | |
| 7 | * published by the Free Software Foundation. | |
| 8 | */ | |
| 9 | ||
| 6709dbbb | 10 | #include <linux/ip.h> |
| 1da177e4 LT |
11 | #include <linux/module.h> |
| 12 | #include <linux/skbuff.h> | |
| 13 | ||
| 14 | #include <linux/netfilter_ipv4/ipt_ttl.h> | |
| 6709dbbb | 15 | #include <linux/netfilter/x_tables.h> |
| 1da177e4 LT |
16 | |
| 17 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); | |
| 2ae15b64 | 18 | MODULE_DESCRIPTION("Xtables: IPv4 TTL field match"); |
| 1da177e4 LT |
19 | MODULE_LICENSE("GPL"); |
| 20 | ||
| f7108a20 | 21 | static bool ttl_mt(const struct sk_buff *skb, const struct xt_match_param *par) |
| 1da177e4 | 22 | { |
| f7108a20 | 23 | const struct ipt_ttl_info *info = par->matchinfo; |
| eddc9ec5 | 24 | const u8 ttl = ip_hdr(skb)->ttl; |
| 1da177e4 LT |
25 | |
| 26 | switch (info->mode) { | |
| 27 | case IPT_TTL_EQ: | |
| 7c4e36bc | 28 | return ttl == info->ttl; |
| 1da177e4 | 29 | case IPT_TTL_NE: |
| 7c4e36bc | 30 | return ttl != info->ttl; |
| 1da177e4 | 31 | case IPT_TTL_LT: |
| 7c4e36bc | 32 | return ttl < info->ttl; |
| 1da177e4 | 33 | case IPT_TTL_GT: |
| 7c4e36bc | 34 | return ttl > info->ttl; |
| 1da177e4 | 35 | default: |
| e905a9ed | 36 | printk(KERN_WARNING "ipt_ttl: unknown mode %d\n", |
| 1da177e4 | 37 | info->mode); |
| 1d93a9cb | 38 | return false; |
| 1da177e4 LT |
39 | } |
| 40 | ||
| 1d93a9cb | 41 | return false; |
| 1da177e4 LT |
42 | } |
| 43 | ||
| d3c5ee6d | 44 | static struct xt_match ttl_mt_reg __read_mostly = { |
| 1da177e4 | 45 | .name = "ttl", |
| ee999d8b | 46 | .family = NFPROTO_IPV4, |
| d3c5ee6d | 47 | .match = ttl_mt, |
| 1d5cd909 | 48 | .matchsize = sizeof(struct ipt_ttl_info), |
| 1da177e4 LT |
49 | .me = THIS_MODULE, |
| 50 | }; | |
| 51 | ||
| d3c5ee6d | 52 | static int __init ttl_mt_init(void) |
| 1da177e4 | 53 | { |
| d3c5ee6d | 54 | return xt_register_match(&ttl_mt_reg); |
| 1da177e4 LT |
55 | } |
| 56 | ||
| d3c5ee6d | 57 | static void __exit ttl_mt_exit(void) |
| 1da177e4 | 58 | { |
| d3c5ee6d | 59 | xt_unregister_match(&ttl_mt_reg); |
| 1da177e4 LT |
60 | } |
| 61 | ||
| d3c5ee6d JE |
62 | module_init(ttl_mt_init); |
| 63 | module_exit(ttl_mt_exit); |