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 void *matchinfo
,
47 struct ip_esp_hdr _esp
, *eh
;
48 const struct ipt_esp
*espinfo
= matchinfo
;
50 /* Must not be a fragment. */
54 eh
= skb_header_pointer(skb
, skb
->nh
.iph
->ihl
* 4,
57 /* We've been asked to examine this packet, and we
58 * can't. Hence, no choice but to drop.
60 duprintf("Dropping evil ESP tinygram.\n");
65 return spi_match(espinfo
->spis
[0], espinfo
->spis
[1],
67 !!(espinfo
->invflags
& IPT_ESP_INV_SPI
));
70 /* Called when user tries to insert an entry of this type. */
72 checkentry(const char *tablename
,
73 const struct ipt_ip
*ip
,
75 unsigned int matchinfosize
,
76 unsigned int hook_mask
)
78 const struct ipt_esp
*espinfo
= matchinfo
;
80 /* Must specify proto == ESP, and no unknown invflags */
81 if (ip
->proto
!= IPPROTO_ESP
|| (ip
->invflags
& IPT_INV_PROTO
)) {
82 duprintf("ipt_esp: Protocol %u != %u\n", ip
->proto
,
86 if (matchinfosize
!= IPT_ALIGN(sizeof(struct ipt_esp
))) {
87 duprintf("ipt_esp: matchsize %u != %u\n",
88 matchinfosize
, IPT_ALIGN(sizeof(struct ipt_esp
)));
91 if (espinfo
->invflags
& ~IPT_ESP_INV_MASK
) {
92 duprintf("ipt_esp: unknown flags %X\n",
100 static struct ipt_match esp_match
= {
103 .checkentry
= &checkentry
,
107 static int __init
init(void)
109 return ipt_register_match(&esp_match
);
112 static void __exit
cleanup(void)
114 ipt_unregister_match(&esp_match
);
118 module_exit(cleanup
);