1 /* x_tables module for setting the IPv4/IPv6 DSCP field, Version 1.8
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.
10 * See RFC2474 for a description of the DSCP field within the IP Header.
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
16 #include <linux/ipv6.h>
17 #include <net/dsfield.h>
19 #include <linux/netfilter/x_tables.h>
20 #include <linux/netfilter/xt_DSCP.h>
23 MODULE_DESCRIPTION("Xtables: DSCP/TOS field modification");
24 MODULE_LICENSE("GPL");
25 MODULE_ALIAS("ipt_DSCP");
26 MODULE_ALIAS("ip6t_DSCP");
27 MODULE_ALIAS("ipt_TOS");
28 MODULE_ALIAS("ip6t_TOS");
31 dscp_tg(struct sk_buff *skb, const struct xt_action_param *par)
33 const struct xt_DSCP_info *dinfo = par->targinfo;
34 u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT;
36 if (dscp != dinfo->dscp) {
37 if (!skb_make_writable(skb, sizeof(struct iphdr)))
40 ipv4_change_dsfield(ip_hdr(skb),
41 (__force __u8)(~XT_DSCP_MASK),
42 dinfo->dscp << XT_DSCP_SHIFT);
49 dscp_tg6(struct sk_buff *skb, const struct xt_action_param *par)
51 const struct xt_DSCP_info *dinfo = par->targinfo;
52 u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT;
54 if (dscp != dinfo->dscp) {
55 if (!skb_make_writable(skb, sizeof(struct ipv6hdr)))
58 ipv6_change_dsfield(ipv6_hdr(skb),
59 (__force __u8)(~XT_DSCP_MASK),
60 dinfo->dscp << XT_DSCP_SHIFT);
65 static int dscp_tg_check(const struct xt_tgchk_param *par)
67 const struct xt_DSCP_info *info = par->targinfo;
69 if (info->dscp > XT_DSCP_MAX) {
70 pr_info("dscp %x out of range\n", info->dscp);
77 tos_tg(struct sk_buff *skb, const struct xt_action_param *par)
79 const struct xt_tos_target_info *info = par->targinfo;
80 struct iphdr *iph = ip_hdr(skb);
83 orig = ipv4_get_dsfield(iph);
84 nv = (orig & ~info->tos_mask) ^ info->tos_value;
87 if (!skb_make_writable(skb, sizeof(struct iphdr)))
90 ipv4_change_dsfield(iph, 0, nv);
97 tos_tg6(struct sk_buff *skb, const struct xt_action_param *par)
99 const struct xt_tos_target_info *info = par->targinfo;
100 struct ipv6hdr *iph = ipv6_hdr(skb);
103 orig = ipv6_get_dsfield(iph);
104 nv = (orig & ~info->tos_mask) ^ info->tos_value;
107 if (!skb_make_writable(skb, sizeof(struct iphdr)))
110 ipv6_change_dsfield(iph, 0, nv);
116 static struct xt_target dscp_tg_reg[] __read_mostly = {
119 .family = NFPROTO_IPV4,
120 .checkentry = dscp_tg_check,
122 .targetsize = sizeof(struct xt_DSCP_info),
128 .family = NFPROTO_IPV6,
129 .checkentry = dscp_tg_check,
131 .targetsize = sizeof(struct xt_DSCP_info),
138 .family = NFPROTO_IPV4,
141 .targetsize = sizeof(struct xt_tos_target_info),
147 .family = NFPROTO_IPV6,
150 .targetsize = sizeof(struct xt_tos_target_info),
155 static int __init dscp_tg_init(void)
157 return xt_register_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg));
160 static void __exit dscp_tg_exit(void)
162 xt_unregister_targets(dscp_tg_reg, ARRAY_SIZE(dscp_tg_reg));
165 module_init(dscp_tg_init);
166 module_exit(dscp_tg_exit);