Commit | Line | Data |
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1da177e4 LT |
1 | /* iptables module for setting the IPv4 DSCP field, Version 1.8 |
2 | * | |
3 | * (C) 2002 by Harald Welte <laforge@netfilter.org> | |
4 | * based on ipt_FTOS.c (C) 2000 by Matthew G. Marsh <mgm@paktronix.com> | |
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 | * See RFC2474 for a description of the DSCP field within the IP Header. | |
11 | * | |
12 | * ipt_DSCP.c,v 1.8 2002/08/06 18:41:57 laforge Exp | |
13 | */ | |
14 | ||
15 | #include <linux/module.h> | |
16 | #include <linux/skbuff.h> | |
17 | #include <linux/ip.h> | |
18 | #include <net/checksum.h> | |
19 | ||
20 | #include <linux/netfilter_ipv4/ip_tables.h> | |
21 | #include <linux/netfilter_ipv4/ipt_DSCP.h> | |
22 | ||
23 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); | |
24 | MODULE_DESCRIPTION("iptables DSCP modification module"); | |
25 | MODULE_LICENSE("GPL"); | |
26 | ||
27 | static unsigned int | |
28 | target(struct sk_buff **pskb, | |
29 | const struct net_device *in, | |
30 | const struct net_device *out, | |
31 | unsigned int hooknum, | |
c4986734 | 32 | const struct xt_target *target, |
1da177e4 LT |
33 | const void *targinfo, |
34 | void *userinfo) | |
35 | { | |
36 | const struct ipt_DSCP_info *dinfo = targinfo; | |
37 | u_int8_t sh_dscp = ((dinfo->dscp << IPT_DSCP_SHIFT) & IPT_DSCP_MASK); | |
38 | ||
39 | ||
40 | if (((*pskb)->nh.iph->tos & IPT_DSCP_MASK) != sh_dscp) { | |
41 | u_int16_t diffs[2]; | |
42 | ||
089af26c | 43 | if (!skb_make_writable(pskb, sizeof(struct iphdr))) |
1da177e4 LT |
44 | return NF_DROP; |
45 | ||
46 | diffs[0] = htons((*pskb)->nh.iph->tos) ^ 0xFFFF; | |
47 | (*pskb)->nh.iph->tos = ((*pskb)->nh.iph->tos & ~IPT_DSCP_MASK) | |
48 | | sh_dscp; | |
49 | diffs[1] = htons((*pskb)->nh.iph->tos); | |
50 | (*pskb)->nh.iph->check | |
51 | = csum_fold(csum_partial((char *)diffs, | |
52 | sizeof(diffs), | |
53 | (*pskb)->nh.iph->check | |
54 | ^ 0xFFFF)); | |
1da177e4 LT |
55 | } |
56 | return IPT_CONTINUE; | |
57 | } | |
58 | ||
59 | static int | |
60 | checkentry(const char *tablename, | |
2e4e6a17 | 61 | const void *e_void, |
c4986734 | 62 | const struct xt_target *target, |
1da177e4 LT |
63 | void *targinfo, |
64 | unsigned int targinfosize, | |
65 | unsigned int hook_mask) | |
66 | { | |
67 | const u_int8_t dscp = ((struct ipt_DSCP_info *)targinfo)->dscp; | |
68 | ||
1da177e4 LT |
69 | if ((dscp > IPT_DSCP_MAX)) { |
70 | printk(KERN_WARNING "DSCP: dscp %x out of range\n", dscp); | |
71 | return 0; | |
72 | } | |
1da177e4 LT |
73 | return 1; |
74 | } | |
75 | ||
76 | static struct ipt_target ipt_dscp_reg = { | |
77 | .name = "DSCP", | |
78 | .target = target, | |
1d5cd909 PM |
79 | .targetsize = sizeof(struct ipt_DSCP_info), |
80 | .table = "mangle", | |
1da177e4 LT |
81 | .checkentry = checkentry, |
82 | .me = THIS_MODULE, | |
83 | }; | |
84 | ||
65b4b4e8 | 85 | static int __init ipt_dscp_init(void) |
1da177e4 LT |
86 | { |
87 | return ipt_register_target(&ipt_dscp_reg); | |
88 | } | |
89 | ||
65b4b4e8 | 90 | static void __exit ipt_dscp_fini(void) |
1da177e4 LT |
91 | { |
92 | ipt_unregister_target(&ipt_dscp_reg); | |
93 | } | |
94 | ||
65b4b4e8 AM |
95 | module_init(ipt_dscp_init); |
96 | module_exit(ipt_dscp_fini); |