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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> | |
c9fd4968 | 21 | #include <linux/netfilter_ipv4/ipt_TOS.h> |
a468701d YK |
22 | |
23 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); | |
2ae15b64 | 24 | MODULE_DESCRIPTION("Xtables: DSCP/TOS field modification"); |
a468701d YK |
25 | MODULE_LICENSE("GPL"); |
26 | MODULE_ALIAS("ipt_DSCP"); | |
27 | MODULE_ALIAS("ip6t_DSCP"); | |
c9fd4968 | 28 | MODULE_ALIAS("ipt_TOS"); |
5c350e5a | 29 | MODULE_ALIAS("ip6t_TOS"); |
a468701d | 30 | |
d3c5ee6d JE |
31 | static unsigned int |
32 | dscp_tg(struct sk_buff *skb, const struct net_device *in, | |
33 | const struct net_device *out, unsigned int hooknum, | |
34 | const struct xt_target *target, const void *targinfo) | |
a468701d YK |
35 | { |
36 | const struct xt_DSCP_info *dinfo = targinfo; | |
3db05fea | 37 | u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT; |
a468701d YK |
38 | |
39 | if (dscp != dinfo->dscp) { | |
3db05fea | 40 | if (!skb_make_writable(skb, sizeof(struct iphdr))) |
a468701d YK |
41 | return NF_DROP; |
42 | ||
3db05fea | 43 | ipv4_change_dsfield(ip_hdr(skb), (__u8)(~XT_DSCP_MASK), |
a468701d YK |
44 | dinfo->dscp << XT_DSCP_SHIFT); |
45 | ||
46 | } | |
47 | return XT_CONTINUE; | |
48 | } | |
49 | ||
d3c5ee6d JE |
50 | static unsigned int |
51 | dscp_tg6(struct sk_buff *skb, const struct net_device *in, | |
52 | const struct net_device *out, unsigned int hooknum, | |
53 | const struct xt_target *target, const void *targinfo) | |
a468701d YK |
54 | { |
55 | const struct xt_DSCP_info *dinfo = targinfo; | |
3db05fea | 56 | u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT; |
a468701d YK |
57 | |
58 | if (dscp != dinfo->dscp) { | |
3db05fea | 59 | if (!skb_make_writable(skb, sizeof(struct ipv6hdr))) |
a468701d YK |
60 | return NF_DROP; |
61 | ||
3db05fea | 62 | ipv6_change_dsfield(ipv6_hdr(skb), (__u8)(~XT_DSCP_MASK), |
a468701d YK |
63 | dinfo->dscp << XT_DSCP_SHIFT); |
64 | } | |
65 | return XT_CONTINUE; | |
66 | } | |
67 | ||
d3c5ee6d JE |
68 | static bool |
69 | dscp_tg_check(const char *tablename, const void *e_void, | |
70 | const struct xt_target *target, void *targinfo, | |
71 | unsigned int hook_mask) | |
a468701d YK |
72 | { |
73 | const u_int8_t dscp = ((struct xt_DSCP_info *)targinfo)->dscp; | |
74 | ||
7c4e36bc | 75 | if (dscp > XT_DSCP_MAX) { |
a468701d | 76 | printk(KERN_WARNING "DSCP: dscp %x out of range\n", dscp); |
e1931b78 | 77 | return false; |
a468701d | 78 | } |
e1931b78 | 79 | return true; |
a468701d YK |
80 | } |
81 | ||
c9fd4968 JE |
82 | static unsigned int |
83 | tos_tg_v0(struct sk_buff *skb, const struct net_device *in, | |
84 | const struct net_device *out, unsigned int hooknum, | |
85 | const struct xt_target *target, const void *targinfo) | |
86 | { | |
87 | const struct ipt_tos_target_info *info = targinfo; | |
88 | struct iphdr *iph = ip_hdr(skb); | |
89 | u_int8_t oldtos; | |
90 | ||
91 | if ((iph->tos & IPTOS_TOS_MASK) != info->tos) { | |
92 | if (!skb_make_writable(skb, sizeof(struct iphdr))) | |
93 | return NF_DROP; | |
94 | ||
95 | iph = ip_hdr(skb); | |
96 | oldtos = iph->tos; | |
97 | iph->tos = (iph->tos & IPTOS_PREC_MASK) | info->tos; | |
98 | csum_replace2(&iph->check, htons(oldtos), htons(iph->tos)); | |
99 | } | |
100 | ||
101 | return XT_CONTINUE; | |
102 | } | |
103 | ||
104 | static bool | |
105 | tos_tg_check_v0(const char *tablename, const void *e_void, | |
106 | const struct xt_target *target, void *targinfo, | |
107 | unsigned int hook_mask) | |
108 | { | |
109 | const u_int8_t tos = ((struct ipt_tos_target_info *)targinfo)->tos; | |
110 | ||
111 | if (tos != IPTOS_LOWDELAY && tos != IPTOS_THROUGHPUT && | |
112 | tos != IPTOS_RELIABILITY && tos != IPTOS_MINCOST && | |
113 | tos != IPTOS_NORMALSVC) { | |
114 | printk(KERN_WARNING "TOS: bad tos value %#x\n", tos); | |
115 | return false; | |
116 | } | |
117 | ||
118 | return true; | |
119 | } | |
120 | ||
5c350e5a JE |
121 | static unsigned int |
122 | tos_tg(struct sk_buff *skb, const struct net_device *in, | |
123 | const struct net_device *out, unsigned int hooknum, | |
124 | const struct xt_target *target, const void *targinfo) | |
125 | { | |
126 | const struct xt_tos_target_info *info = targinfo; | |
127 | struct iphdr *iph = ip_hdr(skb); | |
128 | u_int8_t orig, nv; | |
129 | ||
130 | orig = ipv4_get_dsfield(iph); | |
9bb268ed | 131 | nv = (orig & ~info->tos_mask) ^ info->tos_value; |
5c350e5a JE |
132 | |
133 | if (orig != nv) { | |
134 | if (!skb_make_writable(skb, sizeof(struct iphdr))) | |
135 | return NF_DROP; | |
136 | iph = ip_hdr(skb); | |
cdfe8b97 | 137 | ipv4_change_dsfield(iph, 0, nv); |
5c350e5a JE |
138 | } |
139 | ||
140 | return XT_CONTINUE; | |
141 | } | |
142 | ||
143 | static unsigned int | |
144 | tos_tg6(struct sk_buff *skb, const struct net_device *in, | |
145 | const struct net_device *out, unsigned int hooknum, | |
146 | const struct xt_target *target, const void *targinfo) | |
147 | { | |
148 | const struct xt_tos_target_info *info = targinfo; | |
149 | struct ipv6hdr *iph = ipv6_hdr(skb); | |
150 | u_int8_t orig, nv; | |
151 | ||
152 | orig = ipv6_get_dsfield(iph); | |
153 | nv = (orig & info->tos_mask) ^ info->tos_value; | |
154 | ||
155 | if (orig != nv) { | |
156 | if (!skb_make_writable(skb, sizeof(struct iphdr))) | |
157 | return NF_DROP; | |
158 | iph = ipv6_hdr(skb); | |
cdfe8b97 | 159 | ipv6_change_dsfield(iph, 0, nv); |
5c350e5a JE |
160 | } |
161 | ||
162 | return XT_CONTINUE; | |
163 | } | |
164 | ||
d3c5ee6d | 165 | static struct xt_target dscp_tg_reg[] __read_mostly = { |
4470bbc7 PM |
166 | { |
167 | .name = "DSCP", | |
ee999d8b | 168 | .family = NFPROTO_IPV4, |
d3c5ee6d JE |
169 | .checkentry = dscp_tg_check, |
170 | .target = dscp_tg, | |
4470bbc7 PM |
171 | .targetsize = sizeof(struct xt_DSCP_info), |
172 | .table = "mangle", | |
173 | .me = THIS_MODULE, | |
174 | }, | |
175 | { | |
176 | .name = "DSCP", | |
ee999d8b | 177 | .family = NFPROTO_IPV6, |
d3c5ee6d JE |
178 | .checkentry = dscp_tg_check, |
179 | .target = dscp_tg6, | |
4470bbc7 PM |
180 | .targetsize = sizeof(struct xt_DSCP_info), |
181 | .table = "mangle", | |
182 | .me = THIS_MODULE, | |
183 | }, | |
c9fd4968 JE |
184 | { |
185 | .name = "TOS", | |
186 | .revision = 0, | |
ee999d8b | 187 | .family = NFPROTO_IPV4, |
c9fd4968 JE |
188 | .table = "mangle", |
189 | .target = tos_tg_v0, | |
190 | .targetsize = sizeof(struct ipt_tos_target_info), | |
191 | .checkentry = tos_tg_check_v0, | |
192 | .me = THIS_MODULE, | |
193 | }, | |
5c350e5a JE |
194 | { |
195 | .name = "TOS", | |
196 | .revision = 1, | |
ee999d8b | 197 | .family = NFPROTO_IPV4, |
5c350e5a JE |
198 | .table = "mangle", |
199 | .target = tos_tg, | |
200 | .targetsize = sizeof(struct xt_tos_target_info), | |
201 | .me = THIS_MODULE, | |
202 | }, | |
203 | { | |
204 | .name = "TOS", | |
205 | .revision = 1, | |
ee999d8b | 206 | .family = NFPROTO_IPV6, |
5c350e5a JE |
207 | .table = "mangle", |
208 | .target = tos_tg6, | |
209 | .targetsize = sizeof(struct xt_tos_target_info), | |
210 | .me = THIS_MODULE, | |
211 | }, | |
a468701d YK |
212 | }; |
213 | ||
d3c5ee6d | 214 | static int __init dscp_tg_init(void) |
a468701d | 215 | { |
d3c5ee6d | 216 | return xt_register_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg)); |
a468701d YK |
217 | } |
218 | ||
d3c5ee6d | 219 | static void __exit dscp_tg_exit(void) |
a468701d | 220 | { |
d3c5ee6d | 221 | xt_unregister_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg)); |
a468701d YK |
222 | } |
223 | ||
d3c5ee6d JE |
224 | module_init(dscp_tg_init); |
225 | module_exit(dscp_tg_exit); |