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Commit | Line | Data |
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1da177e4 LT |
1 | /* Kernel module to match ESP parameters. */ |
2 | ||
3 | /* (C) 1999-2000 Yon Uriarte <yon@astaro.de> | |
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> | |
dc5ab2fa | 12 | #include <linux/in.h> |
1da177e4 LT |
13 | #include <linux/ip.h> |
14 | ||
dc5ab2fa YK |
15 | #include <linux/netfilter/xt_esp.h> |
16 | #include <linux/netfilter/x_tables.h> | |
17 | ||
1da177e4 | 18 | #include <linux/netfilter_ipv4/ip_tables.h> |
dc5ab2fa | 19 | #include <linux/netfilter_ipv6/ip6_tables.h> |
1da177e4 LT |
20 | |
21 | MODULE_LICENSE("GPL"); | |
22 | MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>"); | |
2ae15b64 | 23 | MODULE_DESCRIPTION("Xtables: IPsec-ESP packet match"); |
dc5ab2fa YK |
24 | MODULE_ALIAS("ipt_esp"); |
25 | MODULE_ALIAS("ip6t_esp"); | |
1da177e4 | 26 | |
dc5ab2fa | 27 | #if 0 |
1da177e4 LT |
28 | #define duprintf(format, args...) printk(format , ## args) |
29 | #else | |
30 | #define duprintf(format, args...) | |
31 | #endif | |
32 | ||
33 | /* Returns 1 if the spi is matched by the range, 0 otherwise */ | |
1d93a9cb JE |
34 | static inline bool |
35 | spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert) | |
1da177e4 | 36 | { |
1d93a9cb | 37 | bool r; |
dc5ab2fa YK |
38 | duprintf("esp spi_match:%c 0x%x <= 0x%x <= 0x%x", invert ? '!' : ' ', |
39 | min, spi, max); | |
40 | r = (spi >= min && spi <= max) ^ invert; | |
41 | duprintf(" result %s\n", r ? "PASS" : "FAILED"); | |
1da177e4 LT |
42 | return r; |
43 | } | |
44 | ||
f7108a20 | 45 | static bool esp_mt(const struct sk_buff *skb, const struct xt_match_param *par) |
1da177e4 | 46 | { |
3cf93c96 JE |
47 | const struct ip_esp_hdr *eh; |
48 | struct ip_esp_hdr _esp; | |
f7108a20 | 49 | const struct xt_esp *espinfo = par->matchinfo; |
1da177e4 LT |
50 | |
51 | /* Must not be a fragment. */ | |
f7108a20 | 52 | if (par->fragoff != 0) |
1d93a9cb | 53 | return false; |
1da177e4 | 54 | |
f7108a20 | 55 | eh = skb_header_pointer(skb, par->thoff, sizeof(_esp), &_esp); |
1da177e4 LT |
56 | if (eh == NULL) { |
57 | /* We've been asked to examine this packet, and we | |
58 | * can't. Hence, no choice but to drop. | |
59 | */ | |
60 | duprintf("Dropping evil ESP tinygram.\n"); | |
f7108a20 | 61 | *par->hotdrop = true; |
1d93a9cb | 62 | return false; |
1da177e4 LT |
63 | } |
64 | ||
dc5ab2fa YK |
65 | return spi_match(espinfo->spis[0], espinfo->spis[1], ntohl(eh->spi), |
66 | !!(espinfo->invflags & XT_ESP_INV_SPI)); | |
1da177e4 LT |
67 | } |
68 | ||
69 | /* Called when user tries to insert an entry of this type. */ | |
ccb79bdc | 70 | static bool |
d3c5ee6d JE |
71 | esp_mt_check(const char *tablename, const void *ip_void, |
72 | const struct xt_match *match, void *matchinfo, | |
73 | unsigned int hook_mask) | |
1da177e4 | 74 | { |
dc5ab2fa | 75 | const struct xt_esp *espinfo = matchinfo; |
1da177e4 | 76 | |
dc5ab2fa YK |
77 | if (espinfo->invflags & ~XT_ESP_INV_MASK) { |
78 | duprintf("xt_esp: unknown flags %X\n", espinfo->invflags); | |
ccb79bdc | 79 | return false; |
1da177e4 | 80 | } |
dc5ab2fa | 81 | |
ccb79bdc | 82 | return true; |
1da177e4 LT |
83 | } |
84 | ||
d3c5ee6d | 85 | static struct xt_match esp_mt_reg[] __read_mostly = { |
4470bbc7 PM |
86 | { |
87 | .name = "esp", | |
ee999d8b | 88 | .family = NFPROTO_IPV4, |
d3c5ee6d JE |
89 | .checkentry = esp_mt_check, |
90 | .match = esp_mt, | |
4470bbc7 PM |
91 | .matchsize = sizeof(struct xt_esp), |
92 | .proto = IPPROTO_ESP, | |
93 | .me = THIS_MODULE, | |
94 | }, | |
95 | { | |
96 | .name = "esp", | |
ee999d8b | 97 | .family = NFPROTO_IPV6, |
d3c5ee6d JE |
98 | .checkentry = esp_mt_check, |
99 | .match = esp_mt, | |
4470bbc7 PM |
100 | .matchsize = sizeof(struct xt_esp), |
101 | .proto = IPPROTO_ESP, | |
102 | .me = THIS_MODULE, | |
103 | }, | |
dc5ab2fa YK |
104 | }; |
105 | ||
d3c5ee6d | 106 | static int __init esp_mt_init(void) |
1da177e4 | 107 | { |
d3c5ee6d | 108 | return xt_register_matches(esp_mt_reg, ARRAY_SIZE(esp_mt_reg)); |
1da177e4 LT |
109 | } |
110 | ||
d3c5ee6d | 111 | static void __exit esp_mt_exit(void) |
1da177e4 | 112 | { |
d3c5ee6d | 113 | xt_unregister_matches(esp_mt_reg, ARRAY_SIZE(esp_mt_reg)); |
1da177e4 LT |
114 | } |
115 | ||
d3c5ee6d JE |
116 | module_init(esp_mt_init); |
117 | module_exit(esp_mt_exit); |