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>
14 #include <linux/netfilter_ipv4/ipt_esp.h>
15 #include <linux/netfilter_ipv4/ip_tables.h>
17 MODULE_LICENSE("GPL");
18 MODULE_AUTHOR("Yon Uriarte <yon@astaro.de>");
19 MODULE_DESCRIPTION("iptables ESP SPI match module");
21 #ifdef DEBUG_CONNTRACK
22 #define duprintf(format, args...) printk(format , ## args)
24 #define duprintf(format, args...)
27 /* Returns 1 if the spi is matched by the range, 0 otherwise */
29 spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
32 duprintf("esp spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
34 r=(spi >= min && spi <= max) ^ invert;
35 duprintf(" result %s\n",r? "PASS" : "FAILED");
40 match(const struct sk_buff *skb,
41 const struct net_device *in,
42 const struct net_device *out,
43 const struct xt_match *match,
44 const void *matchinfo,
49 struct ip_esp_hdr _esp, *eh;
50 const struct ipt_esp *espinfo = matchinfo;
52 /* Must not be a fragment. */
56 eh = skb_header_pointer(skb, protoff,
59 /* We've been asked to examine this packet, and we
60 * can't. Hence, no choice but to drop.
62 duprintf("Dropping evil ESP tinygram.\n");
67 return spi_match(espinfo->spis[0], espinfo->spis[1],
69 !!(espinfo->invflags & IPT_ESP_INV_SPI));
72 /* Called when user tries to insert an entry of this type. */
74 checkentry(const char *tablename,
76 const struct xt_match *match,
78 unsigned int matchinfosize,
79 unsigned int hook_mask)
81 const struct ipt_esp *espinfo = matchinfo;
83 /* Must specify no unknown invflags */
84 if (espinfo->invflags & ~IPT_ESP_INV_MASK) {
85 duprintf("ipt_esp: unknown flags %X\n", espinfo->invflags);
91 static struct ipt_match esp_match = {
94 .matchsize = sizeof(struct ipt_esp),
96 .checkentry = checkentry,
100 static int __init ipt_esp_init(void)
102 return ipt_register_match(&esp_match);
105 static void __exit ipt_esp_fini(void)
107 ipt_unregister_match(&esp_match);
110 module_init(ipt_esp_init);
111 module_exit(ipt_esp_fini);