1 /* Kernel module to match ESP parameters. */
3 /* (C) 1999-2000 Yon Uriarte <yon@astaro.de>
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.
10 #include <linux/module.h>
11 #include <linux/skbuff.h>
15 #include <linux/netfilter/xt_esp.h>
16 #include <linux/netfilter/x_tables.h>
18 #include <linux/netfilter_ipv4/ip_tables.h>
19 #include <linux/netfilter_ipv6/ip6_tables.h>
21 MODULE_LICENSE("GPL");
22 MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>");
23 MODULE_DESCRIPTION("x_tables ESP SPI match module");
24 MODULE_ALIAS("ipt_esp");
25 MODULE_ALIAS("ip6t_esp");
28 #define duprintf(format, args...) printk(format , ## args)
30 #define duprintf(format, args...)
33 /* Returns 1 if the spi is matched by the range, 0 otherwise */
35 spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
38 duprintf("esp spi_match:%c 0x%x <= 0x%x <= 0x%x", invert ? '!' : ' ',
40 r = (spi >= min && spi <= max) ^ invert;
41 duprintf(" result %s\n", r ? "PASS" : "FAILED");
46 match(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,
55 struct ip_esp_hdr _esp, *eh;
56 const struct xt_esp *espinfo = matchinfo;
58 /* Must not be a fragment. */
62 eh = skb_header_pointer(skb, protoff, sizeof(_esp), &_esp);
64 /* We've been asked to examine this packet, and we
65 * can't. Hence, no choice but to drop.
67 duprintf("Dropping evil ESP tinygram.\n");
72 return spi_match(espinfo->spis[0], espinfo->spis[1], ntohl(eh->spi),
73 !!(espinfo->invflags & XT_ESP_INV_SPI));
76 /* Called when user tries to insert an entry of this type. */
78 checkentry(const char *tablename,
80 const struct xt_match *match,
82 unsigned int hook_mask)
84 const struct xt_esp *espinfo = matchinfo;
86 if (espinfo->invflags & ~XT_ESP_INV_MASK) {
87 duprintf("xt_esp: unknown flags %X\n", espinfo->invflags);
94 static struct xt_match xt_esp_match[] = {
98 .checkentry = checkentry,
100 .matchsize = sizeof(struct xt_esp),
101 .proto = IPPROTO_ESP,
107 .checkentry = checkentry,
109 .matchsize = sizeof(struct xt_esp),
110 .proto = IPPROTO_ESP,
115 static int __init xt_esp_init(void)
117 return xt_register_matches(xt_esp_match, ARRAY_SIZE(xt_esp_match));
120 static void __exit xt_esp_cleanup(void)
122 xt_unregister_matches(xt_esp_match, ARRAY_SIZE(xt_esp_match));
125 module_init(xt_esp_init);
126 module_exit(xt_esp_cleanup);