1 /* Kernel module to match AH parameters. */
3 /* (C) 2001-2002 Andras Kis-Szabo <kisza@sch.bme.hu>
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>
13 #include <linux/ipv6.h>
14 #include <linux/types.h>
15 #include <net/checksum.h>
18 #include <linux/netfilter/x_tables.h>
19 #include <linux/netfilter_ipv6/ip6_tables.h>
20 #include <linux/netfilter_ipv6/ip6t_ah.h>
22 MODULE_LICENSE("GPL");
23 MODULE_DESCRIPTION("IPv6 AH match");
24 MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
29 #define DEBUGP(format, args...)
32 /* Returns 1 if the spi is matched by the range, 0 otherwise */
34 spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert)
37 DEBUGP("ah spi_match:%c 0x%x <= 0x%x <= 0x%x",invert? '!':' ',
39 r = (spi >= min && spi <= max) ^ invert;
40 DEBUGP(" result %s\n",r? "PASS\n" : "FAILED\n");
45 match(const struct sk_buff *skb,
46 const struct net_device *in,
47 const struct net_device *out,
48 const struct xt_match *match,
49 const void *matchinfo,
54 struct ip_auth_hdr _ah;
55 const struct ip_auth_hdr *ah;
56 const struct ip6t_ah *ahinfo = matchinfo;
58 unsigned int hdrlen = 0;
61 err = ipv6_find_hdr(skb, &ptr, NEXTHDR_AUTH, NULL);
68 ah = skb_header_pointer(skb, ptr, sizeof(_ah), &_ah);
74 hdrlen = (ah->hdrlen + 2) << 2;
76 DEBUGP("IPv6 AH LEN %u %u ", hdrlen, ah->hdrlen);
77 DEBUGP("RES %04X ", ah->reserved);
78 DEBUGP("SPI %u %08X\n", ntohl(ah->spi), ntohl(ah->spi));
80 DEBUGP("IPv6 AH spi %02X ",
81 spi_match(ahinfo->spis[0], ahinfo->spis[1],
83 !!(ahinfo->invflags & IP6T_AH_INV_SPI)));
84 DEBUGP("len %02X %04X %02X ",
85 ahinfo->hdrlen, hdrlen,
87 (ahinfo->hdrlen == hdrlen) ^
88 !!(ahinfo->invflags & IP6T_AH_INV_LEN)));
89 DEBUGP("res %02X %04X %02X\n",
90 ahinfo->hdrres, ah->reserved,
91 !(ahinfo->hdrres && ah->reserved));
95 spi_match(ahinfo->spis[0], ahinfo->spis[1],
97 !!(ahinfo->invflags & IP6T_AH_INV_SPI))
100 (ahinfo->hdrlen == hdrlen) ^
101 !!(ahinfo->invflags & IP6T_AH_INV_LEN))
103 !(ahinfo->hdrres && ah->reserved);
106 /* Called when user tries to insert an entry of this type. */
108 checkentry(const char *tablename,
110 const struct xt_match *match,
112 unsigned int hook_mask)
114 const struct ip6t_ah *ahinfo = matchinfo;
116 if (ahinfo->invflags & ~IP6T_AH_INV_MASK) {
117 DEBUGP("ip6t_ah: unknown flags %X\n", ahinfo->invflags);
123 static struct xt_match ah_match = {
127 .matchsize = sizeof(struct ip6t_ah),
128 .checkentry = checkentry,
132 static int __init ip6t_ah_init(void)
134 return xt_register_match(&ah_match);
137 static void __exit ip6t_ah_fini(void)
139 xt_unregister_match(&ah_match);
142 module_init(ip6t_ah_init);
143 module_exit(ip6t_ah_fini);