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Commit | Line | Data |
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1da177e4 LT |
1 | /* Kernel module to match AH parameters. */ |
2 | ||
3 | /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/skbuff.h> | |
14c85021 | 12 | #include <linux/ip.h> |
1da177e4 LT |
13 | #include <linux/ipv6.h> |
14 | #include <linux/types.h> | |
15 | #include <net/checksum.h> | |
16 | #include <net/ipv6.h> | |
17 | ||
6709dbbb | 18 | #include <linux/netfilter/x_tables.h> |
1da177e4 LT |
19 | #include <linux/netfilter_ipv6/ip6_tables.h> |
20 | #include <linux/netfilter_ipv6/ip6t_ah.h> | |
21 | ||
22 | MODULE_LICENSE("GPL"); | |
23 | MODULE_DESCRIPTION("IPv6 AH match"); | |
24 | MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>"); | |
25 | ||
26 | #if 0 | |
27 | #define DEBUGP printk | |
28 | #else | |
29 | #define DEBUGP(format, args...) | |
30 | #endif | |
31 | ||
32 | /* Returns 1 if the spi is matched by the range, 0 otherwise */ | |
33 | static inline int | |
34 | spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert) | |
35 | { | |
36 | int r=0; | |
37 | DEBUGP("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ', | |
38 | min,spi,max); | |
39 | r = (spi >= min && spi <= max) ^ invert; | |
40 | DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n"); | |
41 | return r; | |
42 | } | |
43 | ||
44 | static int | |
45 | match(const struct sk_buff *skb, | |
46 | const struct net_device *in, | |
47 | const struct net_device *out, | |
c4986734 | 48 | const struct xt_match *match, |
1da177e4 LT |
49 | const void *matchinfo, |
50 | int offset, | |
51 | unsigned int protoff, | |
52 | int *hotdrop) | |
53 | { | |
e674d0f3 | 54 | struct ip_auth_hdr *ah, _ah; |
1da177e4 | 55 | const struct ip6t_ah *ahinfo = matchinfo; |
1da177e4 LT |
56 | unsigned int ptr; |
57 | unsigned int hdrlen = 0; | |
6d381634 | 58 | int err; |
1da177e4 | 59 | |
6d381634 PM |
60 | err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL); |
61 | if (err < 0) { | |
62 | if (err != -ENOENT) | |
63 | *hotdrop = 1; | |
1da177e4 | 64 | return 0; |
6d381634 | 65 | } |
1da177e4 | 66 | |
e674d0f3 YK |
67 | ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah); |
68 | if (ah == NULL) { | |
1da177e4 LT |
69 | *hotdrop = 1; |
70 | return 0; | |
71 | } | |
72 | ||
e674d0f3 | 73 | hdrlen = (ah->hdrlen + 2) << 2; |
1da177e4 LT |
74 | |
75 | DEBUGP("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen); | |
76 | DEBUGP("RES %04X ", ah->reserved); | |
77 | DEBUGP("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi)); | |
78 | ||
79 | DEBUGP("IPv6 AH spi %02X ", | |
80 | (spi_match(ahinfo->spis[0], ahinfo->spis[1], | |
1ab1457c YH |
81 | ntohl(ah->spi), |
82 | !!(ahinfo->invflags & IP6T_AH_INV_SPI)))); | |
1da177e4 LT |
83 | DEBUGP("len %02X %04X %02X ", |
84 | ahinfo->hdrlen, hdrlen, | |
85 | (!ahinfo->hdrlen || | |
1ab1457c YH |
86 | (ahinfo->hdrlen == hdrlen) ^ |
87 | !!(ahinfo->invflags & IP6T_AH_INV_LEN))); | |
1da177e4 LT |
88 | DEBUGP("res %02X %04X %02X\n", |
89 | ahinfo->hdrres, ah->reserved, | |
90 | !(ahinfo->hdrres && ah->reserved)); | |
91 | ||
92 | return (ah != NULL) | |
93 | && | |
94 | (spi_match(ahinfo->spis[0], ahinfo->spis[1], | |
1ab1457c YH |
95 | ntohl(ah->spi), |
96 | !!(ahinfo->invflags & IP6T_AH_INV_SPI))) | |
1da177e4 LT |
97 | && |
98 | (!ahinfo->hdrlen || | |
1ab1457c YH |
99 | (ahinfo->hdrlen == hdrlen) ^ |
100 | !!(ahinfo->invflags & IP6T_AH_INV_LEN)) | |
1da177e4 LT |
101 | && |
102 | !(ahinfo->hdrres && ah->reserved); | |
103 | } | |
104 | ||
105 | /* Called when user tries to insert an entry of this type. */ | |
106 | static int | |
107 | checkentry(const char *tablename, | |
1ab1457c | 108 | const void *entry, |
c4986734 | 109 | const struct xt_match *match, |
1ab1457c YH |
110 | void *matchinfo, |
111 | unsigned int hook_mask) | |
1da177e4 LT |
112 | { |
113 | const struct ip6t_ah *ahinfo = matchinfo; | |
114 | ||
1da177e4 LT |
115 | if (ahinfo->invflags & ~IP6T_AH_INV_MASK) { |
116 | DEBUGP("ip6t_ah: unknown flags %X\n", ahinfo->invflags); | |
117 | return 0; | |
118 | } | |
119 | return 1; | |
120 | } | |
121 | ||
6709dbbb | 122 | static struct xt_match ah_match = { |
1da177e4 | 123 | .name = "ah", |
6709dbbb | 124 | .family = AF_INET6, |
7f939713 PM |
125 | .match = match, |
126 | .matchsize = sizeof(struct ip6t_ah), | |
127 | .checkentry = checkentry, | |
1da177e4 LT |
128 | .me = THIS_MODULE, |
129 | }; | |
130 | ||
65b4b4e8 | 131 | static int __init ip6t_ah_init(void) |
1da177e4 | 132 | { |
6709dbbb | 133 | return xt_register_match(&ah_match); |
1da177e4 LT |
134 | } |
135 | ||
65b4b4e8 | 136 | static void __exit ip6t_ah_fini(void) |
1da177e4 | 137 | { |
6709dbbb | 138 | xt_unregister_match(&ah_match); |
1da177e4 LT |
139 | } |
140 | ||
65b4b4e8 AM |
141 | module_init(ip6t_ah_init); |
142 | module_exit(ip6t_ah_fini); |