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a468701d YK |
1 | /* x_tables module for setting the IPv4/IPv6 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. | |
a468701d YK |
11 | */ |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/skbuff.h> | |
15 | #include <linux/ip.h> | |
16 | #include <linux/ipv6.h> | |
17 | #include <net/dsfield.h> | |
18 | ||
19 | #include <linux/netfilter/x_tables.h> | |
20 | #include <linux/netfilter/xt_DSCP.h> | |
21 | ||
22 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); | |
23 | MODULE_DESCRIPTION("x_tables DSCP modification module"); | |
24 | MODULE_LICENSE("GPL"); | |
25 | MODULE_ALIAS("ipt_DSCP"); | |
26 | MODULE_ALIAS("ip6t_DSCP"); | |
27 | ||
3db05fea | 28 | static unsigned int target(struct sk_buff *skb, |
a468701d YK |
29 | const struct net_device *in, |
30 | const struct net_device *out, | |
31 | unsigned int hooknum, | |
32 | const struct xt_target *target, | |
fe1cb108 | 33 | const void *targinfo) |
a468701d YK |
34 | { |
35 | const struct xt_DSCP_info *dinfo = targinfo; | |
3db05fea | 36 | u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT; |
a468701d YK |
37 | |
38 | if (dscp != dinfo->dscp) { | |
3db05fea | 39 | if (!skb_make_writable(skb, sizeof(struct iphdr))) |
a468701d YK |
40 | return NF_DROP; |
41 | ||
3db05fea | 42 | ipv4_change_dsfield(ip_hdr(skb), (__u8)(~XT_DSCP_MASK), |
a468701d YK |
43 | dinfo->dscp << XT_DSCP_SHIFT); |
44 | ||
45 | } | |
46 | return XT_CONTINUE; | |
47 | } | |
48 | ||
3db05fea | 49 | static unsigned int target6(struct sk_buff *skb, |
a468701d YK |
50 | const struct net_device *in, |
51 | const struct net_device *out, | |
52 | unsigned int hooknum, | |
53 | const struct xt_target *target, | |
fe1cb108 | 54 | const void *targinfo) |
a468701d YK |
55 | { |
56 | const struct xt_DSCP_info *dinfo = targinfo; | |
3db05fea | 57 | u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT; |
a468701d YK |
58 | |
59 | if (dscp != dinfo->dscp) { | |
3db05fea | 60 | if (!skb_make_writable(skb, sizeof(struct ipv6hdr))) |
a468701d YK |
61 | return NF_DROP; |
62 | ||
3db05fea | 63 | ipv6_change_dsfield(ipv6_hdr(skb), (__u8)(~XT_DSCP_MASK), |
a468701d YK |
64 | dinfo->dscp << XT_DSCP_SHIFT); |
65 | } | |
66 | return XT_CONTINUE; | |
67 | } | |
68 | ||
e1931b78 JE |
69 | static bool checkentry(const char *tablename, |
70 | const void *e_void, | |
71 | const struct xt_target *target, | |
72 | void *targinfo, | |
73 | unsigned int hook_mask) | |
a468701d YK |
74 | { |
75 | const u_int8_t dscp = ((struct xt_DSCP_info *)targinfo)->dscp; | |
76 | ||
7c4e36bc | 77 | if (dscp > XT_DSCP_MAX) { |
a468701d | 78 | printk(KERN_WARNING "DSCP: dscp %x out of range\n", dscp); |
e1931b78 | 79 | return false; |
a468701d | 80 | } |
e1931b78 | 81 | return true; |
a468701d YK |
82 | } |
83 | ||
9f15c530 | 84 | static struct xt_target xt_dscp_target[] __read_mostly = { |
4470bbc7 PM |
85 | { |
86 | .name = "DSCP", | |
87 | .family = AF_INET, | |
88 | .checkentry = checkentry, | |
89 | .target = target, | |
90 | .targetsize = sizeof(struct xt_DSCP_info), | |
91 | .table = "mangle", | |
92 | .me = THIS_MODULE, | |
93 | }, | |
94 | { | |
95 | .name = "DSCP", | |
96 | .family = AF_INET6, | |
97 | .checkentry = checkentry, | |
98 | .target = target6, | |
99 | .targetsize = sizeof(struct xt_DSCP_info), | |
100 | .table = "mangle", | |
101 | .me = THIS_MODULE, | |
102 | }, | |
a468701d YK |
103 | }; |
104 | ||
105 | static int __init xt_dscp_target_init(void) | |
106 | { | |
4470bbc7 | 107 | return xt_register_targets(xt_dscp_target, ARRAY_SIZE(xt_dscp_target)); |
a468701d YK |
108 | } |
109 | ||
110 | static void __exit xt_dscp_target_fini(void) | |
111 | { | |
4470bbc7 | 112 | xt_unregister_targets(xt_dscp_target, ARRAY_SIZE(xt_dscp_target)); |
a468701d YK |
113 | } |
114 | ||
115 | module_init(xt_dscp_target_init); | |
116 | module_exit(xt_dscp_target_fini); |