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>"); | |
dc5ab2fa YK |
23 | MODULE_DESCRIPTION("x_tables ESP SPI match module"); |
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 */ | |
34 | static inline int | |
35 | spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert) | |
36 | { | |
dc5ab2fa YK |
37 | int r = 0; |
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 | ||
45 | static int | |
46 | match(const struct sk_buff *skb, | |
47 | const struct net_device *in, | |
48 | const struct net_device *out, | |
c4986734 | 49 | const struct xt_match *match, |
1da177e4 LT |
50 | const void *matchinfo, |
51 | int offset, | |
2e4e6a17 | 52 | unsigned int protoff, |
1da177e4 LT |
53 | int *hotdrop) |
54 | { | |
55 | struct ip_esp_hdr _esp, *eh; | |
dc5ab2fa | 56 | const struct xt_esp *espinfo = matchinfo; |
1da177e4 LT |
57 | |
58 | /* Must not be a fragment. */ | |
59 | if (offset) | |
60 | return 0; | |
61 | ||
dc5ab2fa | 62 | eh = skb_header_pointer(skb, protoff, sizeof(_esp), &_esp); |
1da177e4 LT |
63 | if (eh == NULL) { |
64 | /* We've been asked to examine this packet, and we | |
65 | * can't. Hence, no choice but to drop. | |
66 | */ | |
67 | duprintf("Dropping evil ESP tinygram.\n"); | |
68 | *hotdrop = 1; | |
69 | return 0; | |
70 | } | |
71 | ||
dc5ab2fa YK |
72 | return spi_match(espinfo->spis[0], espinfo->spis[1], ntohl(eh->spi), |
73 | !!(espinfo->invflags & XT_ESP_INV_SPI)); | |
1da177e4 LT |
74 | } |
75 | ||
76 | /* Called when user tries to insert an entry of this type. */ | |
77 | static int | |
78 | checkentry(const char *tablename, | |
2e4e6a17 | 79 | const void *ip_void, |
c4986734 | 80 | const struct xt_match *match, |
1da177e4 | 81 | void *matchinfo, |
1da177e4 LT |
82 | unsigned int hook_mask) |
83 | { | |
dc5ab2fa | 84 | const struct xt_esp *espinfo = matchinfo; |
1da177e4 | 85 | |
dc5ab2fa YK |
86 | if (espinfo->invflags & ~XT_ESP_INV_MASK) { |
87 | duprintf("xt_esp: unknown flags %X\n", espinfo->invflags); | |
1da177e4 LT |
88 | return 0; |
89 | } | |
dc5ab2fa | 90 | |
1da177e4 LT |
91 | return 1; |
92 | } | |
93 | ||
4470bbc7 PM |
94 | static struct xt_match xt_esp_match[] = { |
95 | { | |
96 | .name = "esp", | |
97 | .family = AF_INET, | |
98 | .checkentry = checkentry, | |
99 | .match = match, | |
100 | .matchsize = sizeof(struct xt_esp), | |
101 | .proto = IPPROTO_ESP, | |
102 | .me = THIS_MODULE, | |
103 | }, | |
104 | { | |
105 | .name = "esp", | |
106 | .family = AF_INET6, | |
107 | .checkentry = checkentry, | |
108 | .match = match, | |
109 | .matchsize = sizeof(struct xt_esp), | |
110 | .proto = IPPROTO_ESP, | |
111 | .me = THIS_MODULE, | |
112 | }, | |
dc5ab2fa YK |
113 | }; |
114 | ||
115 | static int __init xt_esp_init(void) | |
1da177e4 | 116 | { |
4470bbc7 | 117 | return xt_register_matches(xt_esp_match, ARRAY_SIZE(xt_esp_match)); |
1da177e4 LT |
118 | } |
119 | ||
dc5ab2fa | 120 | static void __exit xt_esp_cleanup(void) |
1da177e4 | 121 | { |
4470bbc7 | 122 | xt_unregister_matches(xt_esp_match, ARRAY_SIZE(xt_esp_match)); |
1da177e4 LT |
123 | } |
124 | ||
dc5ab2fa YK |
125 | module_init(xt_esp_init); |
126 | module_exit(xt_esp_cleanup); |