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a0ca215a MN |
1 | /* |
2 | * Copyright (C)2006 USAGI/WIDE Project | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * Author: | |
9 | * Masahide NAKAMURA @USAGI <masahide.nakamura.cz@hitachi.com> | |
10 | * | |
11 | * Based on net/netfilter/xt_tcpudp.c | |
12 | * | |
13 | */ | |
14 | #include <linux/types.h> | |
15 | #include <linux/module.h> | |
16 | #include <net/ip.h> | |
17 | #include <linux/ipv6.h> | |
18 | #include <net/ipv6.h> | |
19 | #include <net/mip6.h> | |
20 | ||
21 | #include <linux/netfilter/x_tables.h> | |
22 | #include <linux/netfilter_ipv6/ip6t_mh.h> | |
23 | ||
2ae15b64 | 24 | MODULE_DESCRIPTION("Xtables: IPv6 Mobility Header match"); |
a0ca215a MN |
25 | MODULE_LICENSE("GPL"); |
26 | ||
27 | #ifdef DEBUG_IP_FIREWALL_USER | |
28 | #define duprintf(format, args...) printk(format , ## args) | |
29 | #else | |
30 | #define duprintf(format, args...) | |
31 | #endif | |
32 | ||
33 | /* Returns 1 if the type is matched by the range, 0 otherwise */ | |
1d93a9cb JE |
34 | static inline bool |
35 | type_match(u_int8_t min, u_int8_t max, u_int8_t type, bool invert) | |
a0ca215a | 36 | { |
1d93a9cb | 37 | return (type >= min && type <= max) ^ invert; |
a0ca215a MN |
38 | } |
39 | ||
1d93a9cb | 40 | static bool |
d3c5ee6d JE |
41 | mh_mt6(const struct sk_buff *skb, const struct net_device *in, |
42 | const struct net_device *out, const struct xt_match *match, | |
43 | const void *matchinfo, int offset, unsigned int protoff, bool *hotdrop) | |
a0ca215a | 44 | { |
a47362a2 JE |
45 | struct ip6_mh _mh; |
46 | const struct ip6_mh *mh; | |
a0ca215a MN |
47 | const struct ip6t_mh *mhinfo = matchinfo; |
48 | ||
49 | /* Must not be a fragment. */ | |
50 | if (offset) | |
1d93a9cb | 51 | return false; |
a0ca215a MN |
52 | |
53 | mh = skb_header_pointer(skb, protoff, sizeof(_mh), &_mh); | |
54 | if (mh == NULL) { | |
55 | /* We've been asked to examine this packet, and we | |
56 | can't. Hence, no choice but to drop. */ | |
57 | duprintf("Dropping evil MH tinygram.\n"); | |
cff533ac | 58 | *hotdrop = true; |
1d93a9cb | 59 | return false; |
a0ca215a MN |
60 | } |
61 | ||
138939e0 MN |
62 | if (mh->ip6mh_proto != IPPROTO_NONE) { |
63 | duprintf("Dropping invalid MH Payload Proto: %u\n", | |
64 | mh->ip6mh_proto); | |
cff533ac | 65 | *hotdrop = true; |
1d93a9cb | 66 | return false; |
138939e0 MN |
67 | } |
68 | ||
a0ca215a MN |
69 | return type_match(mhinfo->types[0], mhinfo->types[1], mh->ip6mh_type, |
70 | !!(mhinfo->invflags & IP6T_MH_INV_TYPE)); | |
71 | } | |
72 | ||
73 | /* Called when user tries to insert an entry of this type. */ | |
ccb79bdc | 74 | static bool |
d3c5ee6d JE |
75 | mh_mt6_check(const char *tablename, const void *entry, |
76 | const struct xt_match *match, void *matchinfo, | |
77 | unsigned int hook_mask) | |
a0ca215a MN |
78 | { |
79 | const struct ip6t_mh *mhinfo = matchinfo; | |
80 | ||
81 | /* Must specify no unknown invflags */ | |
82 | return !(mhinfo->invflags & ~IP6T_MH_INV_MASK); | |
83 | } | |
84 | ||
d3c5ee6d | 85 | static struct xt_match mh_mt6_reg __read_mostly = { |
a0ca215a MN |
86 | .name = "mh", |
87 | .family = AF_INET6, | |
d3c5ee6d JE |
88 | .checkentry = mh_mt6_check, |
89 | .match = mh_mt6, | |
a0ca215a MN |
90 | .matchsize = sizeof(struct ip6t_mh), |
91 | .proto = IPPROTO_MH, | |
92 | .me = THIS_MODULE, | |
93 | }; | |
94 | ||
d3c5ee6d | 95 | static int __init mh_mt6_init(void) |
a0ca215a | 96 | { |
d3c5ee6d | 97 | return xt_register_match(&mh_mt6_reg); |
a0ca215a MN |
98 | } |
99 | ||
d3c5ee6d | 100 | static void __exit mh_mt6_exit(void) |
a0ca215a | 101 | { |
d3c5ee6d | 102 | xt_unregister_match(&mh_mt6_reg); |
a0ca215a MN |
103 | } |
104 | ||
d3c5ee6d JE |
105 | module_init(mh_mt6_init); |
106 | module_exit(mh_mt6_exit); |