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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
a468701d YK |
2 | /* x_tables module for setting the IPv4/IPv6 DSCP field, Version 1.8 |
3 | * | |
4 | * (C) 2002 by Harald Welte <laforge@netfilter.org> | |
5 | * based on ipt_FTOS.c (C) 2000 by Matthew G. Marsh <mgm@paktronix.com> | |
6 | * | |
a468701d | 7 | * See RFC2474 for a description of the DSCP field within the IP Header. |
a468701d | 8 | */ |
8bee4bad | 9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
a468701d YK |
10 | #include <linux/module.h> |
11 | #include <linux/skbuff.h> | |
12 | #include <linux/ip.h> | |
13 | #include <linux/ipv6.h> | |
14 | #include <net/dsfield.h> | |
15 | ||
16 | #include <linux/netfilter/x_tables.h> | |
17 | #include <linux/netfilter/xt_DSCP.h> | |
18 | ||
19 | MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); | |
2ae15b64 | 20 | MODULE_DESCRIPTION("Xtables: DSCP/TOS field modification"); |
a468701d YK |
21 | MODULE_LICENSE("GPL"); |
22 | MODULE_ALIAS("ipt_DSCP"); | |
23 | MODULE_ALIAS("ip6t_DSCP"); | |
c9fd4968 | 24 | MODULE_ALIAS("ipt_TOS"); |
5c350e5a | 25 | MODULE_ALIAS("ip6t_TOS"); |
a468701d | 26 | |
d3c5ee6d | 27 | static unsigned int |
4b560b44 | 28 | dscp_tg(struct sk_buff *skb, const struct xt_action_param *par) |
a468701d | 29 | { |
7eb35586 | 30 | const struct xt_DSCP_info *dinfo = par->targinfo; |
3db05fea | 31 | u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT; |
a468701d YK |
32 | |
33 | if (dscp != dinfo->dscp) { | |
2cf6bffc | 34 | if (skb_ensure_writable(skb, sizeof(struct iphdr))) |
a468701d YK |
35 | return NF_DROP; |
36 | ||
56768644 FW |
37 | ipv4_change_dsfield(ip_hdr(skb), |
38 | (__force __u8)(~XT_DSCP_MASK), | |
a468701d YK |
39 | dinfo->dscp << XT_DSCP_SHIFT); |
40 | ||
41 | } | |
42 | return XT_CONTINUE; | |
43 | } | |
44 | ||
d3c5ee6d | 45 | static unsigned int |
4b560b44 | 46 | dscp_tg6(struct sk_buff *skb, const struct xt_action_param *par) |
a468701d | 47 | { |
7eb35586 | 48 | const struct xt_DSCP_info *dinfo = par->targinfo; |
3db05fea | 49 | u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT; |
a468701d YK |
50 | |
51 | if (dscp != dinfo->dscp) { | |
2cf6bffc | 52 | if (skb_ensure_writable(skb, sizeof(struct ipv6hdr))) |
a468701d YK |
53 | return NF_DROP; |
54 | ||
56768644 FW |
55 | ipv6_change_dsfield(ipv6_hdr(skb), |
56 | (__force __u8)(~XT_DSCP_MASK), | |
a468701d YK |
57 | dinfo->dscp << XT_DSCP_SHIFT); |
58 | } | |
59 | return XT_CONTINUE; | |
60 | } | |
61 | ||
135367b8 | 62 | static int dscp_tg_check(const struct xt_tgchk_param *par) |
a468701d | 63 | { |
af5d6dc2 | 64 | const struct xt_DSCP_info *info = par->targinfo; |
a468701d | 65 | |
0cc9501f | 66 | if (info->dscp > XT_DSCP_MAX) |
4a5a5c73 | 67 | return -EDOM; |
d6b00a53 | 68 | return 0; |
a468701d YK |
69 | } |
70 | ||
5c350e5a | 71 | static unsigned int |
4b560b44 | 72 | tos_tg(struct sk_buff *skb, const struct xt_action_param *par) |
5c350e5a | 73 | { |
7eb35586 | 74 | const struct xt_tos_target_info *info = par->targinfo; |
5c350e5a JE |
75 | struct iphdr *iph = ip_hdr(skb); |
76 | u_int8_t orig, nv; | |
77 | ||
78 | orig = ipv4_get_dsfield(iph); | |
9bb268ed | 79 | nv = (orig & ~info->tos_mask) ^ info->tos_value; |
5c350e5a JE |
80 | |
81 | if (orig != nv) { | |
2cf6bffc | 82 | if (skb_ensure_writable(skb, sizeof(struct iphdr))) |
5c350e5a JE |
83 | return NF_DROP; |
84 | iph = ip_hdr(skb); | |
cdfe8b97 | 85 | ipv4_change_dsfield(iph, 0, nv); |
5c350e5a JE |
86 | } |
87 | ||
88 | return XT_CONTINUE; | |
89 | } | |
90 | ||
91 | static unsigned int | |
4b560b44 | 92 | tos_tg6(struct sk_buff *skb, const struct xt_action_param *par) |
5c350e5a | 93 | { |
7eb35586 | 94 | const struct xt_tos_target_info *info = par->targinfo; |
5c350e5a JE |
95 | struct ipv6hdr *iph = ipv6_hdr(skb); |
96 | u_int8_t orig, nv; | |
97 | ||
98 | orig = ipv6_get_dsfield(iph); | |
1ed2f73d | 99 | nv = (orig & ~info->tos_mask) ^ info->tos_value; |
5c350e5a JE |
100 | |
101 | if (orig != nv) { | |
2cf6bffc | 102 | if (skb_ensure_writable(skb, sizeof(struct iphdr))) |
5c350e5a JE |
103 | return NF_DROP; |
104 | iph = ipv6_hdr(skb); | |
cdfe8b97 | 105 | ipv6_change_dsfield(iph, 0, nv); |
5c350e5a JE |
106 | } |
107 | ||
108 | return XT_CONTINUE; | |
109 | } | |
110 | ||
d3c5ee6d | 111 | static struct xt_target dscp_tg_reg[] __read_mostly = { |
4470bbc7 PM |
112 | { |
113 | .name = "DSCP", | |
ee999d8b | 114 | .family = NFPROTO_IPV4, |
d3c5ee6d JE |
115 | .checkentry = dscp_tg_check, |
116 | .target = dscp_tg, | |
4470bbc7 PM |
117 | .targetsize = sizeof(struct xt_DSCP_info), |
118 | .table = "mangle", | |
119 | .me = THIS_MODULE, | |
120 | }, | |
121 | { | |
122 | .name = "DSCP", | |
ee999d8b | 123 | .family = NFPROTO_IPV6, |
d3c5ee6d JE |
124 | .checkentry = dscp_tg_check, |
125 | .target = dscp_tg6, | |
4470bbc7 PM |
126 | .targetsize = sizeof(struct xt_DSCP_info), |
127 | .table = "mangle", | |
128 | .me = THIS_MODULE, | |
129 | }, | |
5c350e5a JE |
130 | { |
131 | .name = "TOS", | |
132 | .revision = 1, | |
ee999d8b | 133 | .family = NFPROTO_IPV4, |
5c350e5a JE |
134 | .table = "mangle", |
135 | .target = tos_tg, | |
136 | .targetsize = sizeof(struct xt_tos_target_info), | |
137 | .me = THIS_MODULE, | |
138 | }, | |
139 | { | |
140 | .name = "TOS", | |
141 | .revision = 1, | |
ee999d8b | 142 | .family = NFPROTO_IPV6, |
5c350e5a JE |
143 | .table = "mangle", |
144 | .target = tos_tg6, | |
145 | .targetsize = sizeof(struct xt_tos_target_info), | |
146 | .me = THIS_MODULE, | |
147 | }, | |
a468701d YK |
148 | }; |
149 | ||
d3c5ee6d | 150 | static int __init dscp_tg_init(void) |
a468701d | 151 | { |
d3c5ee6d | 152 | return xt_register_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg)); |
a468701d YK |
153 | } |
154 | ||
d3c5ee6d | 155 | static void __exit dscp_tg_exit(void) |
a468701d | 156 | { |
d3c5ee6d | 157 | xt_unregister_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg)); |
a468701d YK |
158 | } |
159 | ||
d3c5ee6d JE |
160 | module_init(dscp_tg_init); |
161 | module_exit(dscp_tg_exit); |