1 /* Kernel module to match ESP parameters. */
2 /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
10 #include <linux/module.h>
11 #include <linux/skbuff.h>
12 #include <linux/ipv6.h>
13 #include <linux/types.h>
14 #include <net/checksum.h>
17 #include <linux/netfilter_ipv6/ip6_tables.h>
18 #include <linux/netfilter_ipv6/ip6t_esp.h>
20 MODULE_LICENSE("GPL");
21 MODULE_DESCRIPTION("IPv6 ESP match");
22 MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
27 #define DEBUGP(format, args...)
30 /* Returns 1 if the spi is matched by the range, 0 otherwise */
32 spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, int invert)
35 DEBUGP("esp spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
37 r=(spi >= min && spi <= max) ^ invert;
38 DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");
43 match(const struct sk_buff *skb,
44 const struct net_device *in,
45 const struct net_device *out,
46 const void *matchinfo,
52 struct ip_esp_hdr *esp = NULL;
53 const struct ip6t_esp *espinfo = matchinfo;
59 /* Make sure this isn't an evil packet */
60 /*DEBUGP("ipv6_esp entered \n");*/
62 /* type of the 1st exthdr */
63 nexthdr = skb->nh.ipv6h->nexthdr;
64 /* pointer to the 1st exthdr */
65 ptr = sizeof(struct ipv6hdr);
66 /* available length */
70 while (ip6t_ext_hdr(nexthdr)) {
71 struct ipv6_opt_hdr *hdr;
74 DEBUGP("ipv6_esp header iteration \n");
76 /* Is there enough space for the next ext header? */
77 if (len < (int)sizeof(struct ipv6_opt_hdr))
79 /* No more exthdr -> evaluate */
80 if (nexthdr == NEXTHDR_NONE) {
84 if (nexthdr == NEXTHDR_ESP) {
89 hdr=(struct ipv6_opt_hdr *)skb->data+ptr;
91 /* Calculate the header length */
92 if (nexthdr == NEXTHDR_FRAGMENT) {
94 } else if (nexthdr == NEXTHDR_AUTH)
95 hdrlen = (hdr->hdrlen+2)<<2;
97 hdrlen = ipv6_optlen(hdr);
102 case NEXTHDR_ROUTING:
103 case NEXTHDR_FRAGMENT:
108 DEBUGP("ipv6_esp match: unknown nextheader %u\n",nexthdr);
113 nexthdr = hdr->nexthdr;
116 if ( ptr > skb->len ) {
117 DEBUGP("ipv6_esp: new pointer too large! \n");
122 /* ESP header not found */
123 if ( temp != MASK_ESP ) return 0;
125 if (len < (int)sizeof(struct ip_esp_hdr)){
130 esp = (struct ip_esp_hdr *) (skb->data + ptr);
132 DEBUGP("IPv6 ESP SPI %u %08X\n", ntohl(esp->spi), ntohl(esp->spi));
135 && spi_match(espinfo->spis[0], espinfo->spis[1],
137 !!(espinfo->invflags & IP6T_ESP_INV_SPI));
140 /* Called when user tries to insert an entry of this type. */
142 checkentry(const char *tablename,
143 const struct ip6t_ip6 *ip,
145 unsigned int matchinfosize,
146 unsigned int hook_mask)
148 const struct ip6t_esp *espinfo = matchinfo;
150 if (matchinfosize != IP6T_ALIGN(sizeof(struct ip6t_esp))) {
151 DEBUGP("ip6t_esp: matchsize %u != %u\n",
152 matchinfosize, IP6T_ALIGN(sizeof(struct ip6t_esp)));
155 if (espinfo->invflags & ~IP6T_ESP_INV_MASK) {
156 DEBUGP("ip6t_esp: unknown flags %X\n",
164 static struct ip6t_match esp_match = {
167 .checkentry = &checkentry,
171 static int __init init(void)
173 return ip6t_register_match(&esp_match);
176 static void __exit cleanup(void)
178 ip6t_unregister_match(&esp_match);
182 module_exit(cleanup);