Commit | Line | Data |
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1da177e4 LT |
1 | /* This is a module which is used for setting the TOS field of a packet. */ |
2 | ||
3 | /* (C) 1999-2001 Paul `Rusty' Russell | |
4 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | */ | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/skbuff.h> | |
13 | #include <linux/ip.h> | |
14 | #include <net/checksum.h> | |
15 | ||
16 | #include <linux/netfilter_ipv4/ip_tables.h> | |
17 | #include <linux/netfilter_ipv4/ipt_TOS.h> | |
18 | ||
19 | MODULE_LICENSE("GPL"); | |
20 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
21 | MODULE_DESCRIPTION("iptables TOS mangling module"); | |
22 | ||
23 | static unsigned int | |
24 | target(struct sk_buff **pskb, | |
25 | const struct net_device *in, | |
26 | const struct net_device *out, | |
27 | unsigned int hooknum, | |
c4986734 | 28 | const struct xt_target *target, |
1da177e4 LT |
29 | const void *targinfo, |
30 | void *userinfo) | |
31 | { | |
32 | const struct ipt_tos_target_info *tosinfo = targinfo; | |
33 | ||
34 | if (((*pskb)->nh.iph->tos & IPTOS_TOS_MASK) != tosinfo->tos) { | |
35 | u_int16_t diffs[2]; | |
36 | ||
089af26c | 37 | if (!skb_make_writable(pskb, sizeof(struct iphdr))) |
1da177e4 LT |
38 | return NF_DROP; |
39 | ||
40 | diffs[0] = htons((*pskb)->nh.iph->tos) ^ 0xFFFF; | |
41 | (*pskb)->nh.iph->tos | |
42 | = ((*pskb)->nh.iph->tos & IPTOS_PREC_MASK) | |
43 | | tosinfo->tos; | |
44 | diffs[1] = htons((*pskb)->nh.iph->tos); | |
45 | (*pskb)->nh.iph->check | |
46 | = csum_fold(csum_partial((char *)diffs, | |
47 | sizeof(diffs), | |
48 | (*pskb)->nh.iph->check | |
49 | ^0xFFFF)); | |
1da177e4 LT |
50 | } |
51 | return IPT_CONTINUE; | |
52 | } | |
53 | ||
54 | static int | |
55 | checkentry(const char *tablename, | |
2e4e6a17 | 56 | const void *e_void, |
c4986734 | 57 | const struct xt_target *target, |
1da177e4 LT |
58 | void *targinfo, |
59 | unsigned int targinfosize, | |
60 | unsigned int hook_mask) | |
61 | { | |
62 | const u_int8_t tos = ((struct ipt_tos_target_info *)targinfo)->tos; | |
63 | ||
1da177e4 LT |
64 | if (tos != IPTOS_LOWDELAY |
65 | && tos != IPTOS_THROUGHPUT | |
66 | && tos != IPTOS_RELIABILITY | |
67 | && tos != IPTOS_MINCOST | |
68 | && tos != IPTOS_NORMALSVC) { | |
69 | printk(KERN_WARNING "TOS: bad tos value %#x\n", tos); | |
70 | return 0; | |
71 | } | |
1da177e4 LT |
72 | return 1; |
73 | } | |
74 | ||
75 | static struct ipt_target ipt_tos_reg = { | |
76 | .name = "TOS", | |
77 | .target = target, | |
1d5cd909 PM |
78 | .targetsize = sizeof(struct ipt_tos_target_info), |
79 | .table = "mangle", | |
1da177e4 LT |
80 | .checkentry = checkentry, |
81 | .me = THIS_MODULE, | |
82 | }; | |
83 | ||
84 | static int __init init(void) | |
85 | { | |
86 | return ipt_register_target(&ipt_tos_reg); | |
87 | } | |
88 | ||
89 | static void __exit fini(void) | |
90 | { | |
91 | ipt_unregister_target(&ipt_tos_reg); | |
92 | } | |
93 | ||
94 | module_init(init); | |
95 | module_exit(fini); |