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 | ||
| d3c5ee6d JE |
21 | static bool |
| 22 | ttl_mt(const struct sk_buff *skb, const struct net_device *in, | |
| 23 | const struct net_device *out, const struct xt_match *match, | |
| 24 | const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop) | |
| 1da177e4 LT |
25 | { |
| 26 | const struct ipt_ttl_info *info = matchinfo; | |
| eddc9ec5 | 27 | const u8 ttl = ip_hdr(skb)->ttl; |
| 1da177e4 LT |
28 | |
| 29 | switch (info->mode) { | |
| 30 | case IPT_TTL_EQ: | |
| 7c4e36bc | 31 | return ttl == info->ttl; |
| 1da177e4 | 32 | case IPT_TTL_NE: |
| 7c4e36bc | 33 | return ttl != info->ttl; |
| 1da177e4 | 34 | case IPT_TTL_LT: |
| 7c4e36bc | 35 | return ttl < info->ttl; |
| 1da177e4 | 36 | case IPT_TTL_GT: |
| 7c4e36bc | 37 | return ttl > info->ttl; |
| 1da177e4 | 38 | default: |
| e905a9ed | 39 | printk(KERN_WARNING "ipt_ttl: unknown mode %d\n", |
| 1da177e4 | 40 | info->mode); |
| 1d93a9cb | 41 | return false; |
| 1da177e4 LT |
42 | } |
| 43 | ||
| 1d93a9cb | 44 | return false; |
| 1da177e4 LT |
45 | } |
| 46 | ||
| d3c5ee6d | 47 | static struct xt_match ttl_mt_reg __read_mostly = { |
| 1da177e4 | 48 | .name = "ttl", |
| 6709dbbb | 49 | .family = AF_INET, |
| d3c5ee6d | 50 | .match = ttl_mt, |
| 1d5cd909 | 51 | .matchsize = sizeof(struct ipt_ttl_info), |
| 1da177e4 LT |
52 | .me = THIS_MODULE, |
| 53 | }; | |
| 54 | ||
| d3c5ee6d | 55 | static int __init ttl_mt_init(void) |
| 1da177e4 | 56 | { |
| d3c5ee6d | 57 | return xt_register_match(&ttl_mt_reg); |
| 1da177e4 LT |
58 | } |
| 59 | ||
| d3c5ee6d | 60 | static void __exit ttl_mt_exit(void) |
| 1da177e4 | 61 | { |
| d3c5ee6d | 62 | xt_unregister_match(&ttl_mt_reg); |
| 1da177e4 LT |
63 | } |
| 64 | ||
| d3c5ee6d JE |
65 | module_init(ttl_mt_init); |
| 66 | module_exit(ttl_mt_exit); |