1 // SPDX-License-Identifier: GPL-2.0-only
2 /* IP tables module for matching the value of the IPv4/IPv6 DSCP field
3 *
4 * (C) 2002 by Harald Welte <laforge@netfilter.org>
5 */
6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
7 #include <linux/module.h>
8 #include <linux/skbuff.h>
9 #include <linux/ip.h>
10 #include <linux/ipv6.h>
11 #include <net/dsfield.h>
12
13 #include <linux/netfilter/x_tables.h>
14 #include <linux/netfilter/xt_dscp.h>
15
16 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
17 MODULE_DESCRIPTION("Xtables: DSCP/TOS field match");
18 MODULE_LICENSE("GPL");
19 MODULE_ALIAS("ipt_dscp");
20 MODULE_ALIAS("ip6t_dscp");
21 MODULE_ALIAS("ipt_tos");
22 MODULE_ALIAS("ip6t_tos");
23
24 static bool
dscp_mt(const struct sk_buff * skb,struct xt_action_param * par)25 dscp_mt(const struct sk_buff *skb, struct xt_action_param *par)
26 {
27 const struct xt_dscp_info *info = par->matchinfo;
28 u_int8_t dscp = ipv4_get_dsfield(ip_hdr(skb)) >> XT_DSCP_SHIFT;
29
30 return (dscp == info->dscp) ^ !!info->invert;
31 }
32
33 static bool
dscp_mt6(const struct sk_buff * skb,struct xt_action_param * par)34 dscp_mt6(const struct sk_buff *skb, struct xt_action_param *par)
35 {
36 const struct xt_dscp_info *info = par->matchinfo;
37 u_int8_t dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> XT_DSCP_SHIFT;
38
39 return (dscp == info->dscp) ^ !!info->invert;
40 }
41
dscp_mt_check(const struct xt_mtchk_param * par)42 static int dscp_mt_check(const struct xt_mtchk_param *par)
43 {
44 const struct xt_dscp_info *info = par->matchinfo;
45
46 if (info->dscp > XT_DSCP_MAX)
47 return -EDOM;
48
49 return 0;
50 }
51
tos_mt(const struct sk_buff * skb,struct xt_action_param * par)52 static bool tos_mt(const struct sk_buff *skb, struct xt_action_param *par)
53 {
54 const struct xt_tos_match_info *info = par->matchinfo;
55
56 if (xt_family(par) == NFPROTO_IPV4)
57 return ((ip_hdr(skb)->tos & info->tos_mask) ==
58 info->tos_value) ^ !!info->invert;
59 else
60 return ((ipv6_get_dsfield(ipv6_hdr(skb)) & info->tos_mask) ==
61 info->tos_value) ^ !!info->invert;
62 }
63
64 static struct xt_match dscp_mt_reg[] __read_mostly = {
65 {
66 .name = "dscp",
67 .family = NFPROTO_IPV4,
68 .checkentry = dscp_mt_check,
69 .match = dscp_mt,
70 .matchsize = sizeof(struct xt_dscp_info),
71 .me = THIS_MODULE,
72 },
73 {
74 .name = "dscp",
75 .family = NFPROTO_IPV6,
76 .checkentry = dscp_mt_check,
77 .match = dscp_mt6,
78 .matchsize = sizeof(struct xt_dscp_info),
79 .me = THIS_MODULE,
80 },
81 {
82 .name = "tos",
83 .revision = 1,
84 .family = NFPROTO_IPV4,
85 .match = tos_mt,
86 .matchsize = sizeof(struct xt_tos_match_info),
87 .me = THIS_MODULE,
88 },
89 {
90 .name = "tos",
91 .revision = 1,
92 .family = NFPROTO_IPV6,
93 .match = tos_mt,
94 .matchsize = sizeof(struct xt_tos_match_info),
95 .me = THIS_MODULE,
96 },
97 };
98
dscp_mt_init(void)99 static int __init dscp_mt_init(void)
100 {
101 return xt_register_matches(dscp_mt_reg, ARRAY_SIZE(dscp_mt_reg));
102 }
103
dscp_mt_exit(void)104 static void __exit dscp_mt_exit(void)
105 {
106 xt_unregister_matches(dscp_mt_reg, ARRAY_SIZE(dscp_mt_reg));
107 }
108
109 module_init(dscp_mt_init);
110 module_exit(dscp_mt_exit);
111