tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
fork
Configure Feed
Select the types of activity you want to include in your feed.
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>
12#include <linux/in.h>
13#include <linux/ip.h>
14
15#include <linux/netfilter/xt_esp.h>
16#include <linux/netfilter/x_tables.h>
17
18#include <linux/netfilter_ipv4/ip_tables.h>
19#include <linux/netfilter_ipv6/ip6_tables.h>
20
21MODULE_LICENSE("GPL");
22MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>");
23MODULE_DESCRIPTION("x_tables ESP SPI match module");
24MODULE_ALIAS("ipt_esp");
25MODULE_ALIAS("ip6t_esp");
26
27#if 0
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 */
34static inline int
35spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
36{
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");
42 return r;
43}
44
45static int
46match(const struct sk_buff *skb,
47 const struct net_device *in,
48 const struct net_device *out,
49 const struct xt_match *match,
50 const void *matchinfo,
51 int offset,
52 unsigned int protoff,
53 int *hotdrop)
54{
55 struct ip_esp_hdr _esp, *eh;
56 const struct xt_esp *espinfo = matchinfo;
57
58 /* Must not be a fragment. */
59 if (offset)
60 return 0;
61
62 eh = skb_header_pointer(skb, protoff, sizeof(_esp), &_esp);
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
72 return spi_match(espinfo->spis[0], espinfo->spis[1], ntohl(eh->spi),
73 !!(espinfo->invflags & XT_ESP_INV_SPI));
74}
75
76/* Called when user tries to insert an entry of this type. */
77static int
78checkentry(const char *tablename,
79 const void *ip_void,
80 const struct xt_match *match,
81 void *matchinfo,
82 unsigned int matchinfosize,
83 unsigned int hook_mask)
84{
85 const struct xt_esp *espinfo = matchinfo;
86
87 if (espinfo->invflags & ~XT_ESP_INV_MASK) {
88 duprintf("xt_esp: unknown flags %X\n", espinfo->invflags);
89 return 0;
90 }
91
92 return 1;
93}
94
95static struct xt_match esp_match = {
96 .name = "esp",
97 .family = AF_INET,
98 .proto = IPPROTO_ESP,
99 .match = &match,
100 .matchsize = sizeof(struct xt_esp),
101 .checkentry = &checkentry,
102 .me = THIS_MODULE,
103};
104
105static struct xt_match esp6_match = {
106 .name = "esp",
107 .family = AF_INET6,
108 .proto = IPPROTO_ESP,
109 .match = &match,
110 .matchsize = sizeof(struct xt_esp),
111 .checkentry = &checkentry,
112 .me = THIS_MODULE,
113};
114
115static int __init xt_esp_init(void)
116{
117 int ret;
118 ret = xt_register_match(&esp_match);
119 if (ret)
120 return ret;
121
122 ret = xt_register_match(&esp6_match);
123 if (ret)
124 xt_unregister_match(&esp_match);
125
126 return ret;
127}
128
129static void __exit xt_esp_cleanup(void)
130{
131 xt_unregister_match(&esp_match);
132 xt_unregister_match(&esp6_match);
133}
134
135module_init(xt_esp_init);
136module_exit(xt_esp_cleanup);