1 /* Kernel module to match Hop-by-Hop and Destination 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>
12 #include <linux/ipv6.h>
13 #include <linux/types.h>
14 #include <net/checksum.h>
17 #include <asm/byteorder.h>
19 #include <linux/netfilter/x_tables.h>
20 #include <linux/netfilter_ipv6/ip6_tables.h>
21 #include <linux/netfilter_ipv6/ip6t_opts.h>
23 MODULE_LICENSE("GPL");
24 MODULE_DESCRIPTION("Xtables: IPv6 Hop-By-Hop and Destination Header match");
25 MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
26 MODULE_ALIAS("ip6t_dst");
31 * 1 -> must drop the packet
32 * 2 -> send ICMP PARM PROB regardless and drop packet
33 * 3 -> Send ICMP if not a multicast address and drop packet
36 * 1 -> can change the routing
38 * 0 -> Pad1 (only 1 byte!)
39 * 1 -> PadN LENGTH info (total length = length + 2)
40 * C0 | 2 -> JUMBO 4 x x x x ( xxxx > 64k )
45 hbh_mt6(const struct sk_buff
*skb
, const struct net_device
*in
,
46 const struct net_device
*out
, const struct xt_match
*match
,
47 const void *matchinfo
, int offset
, unsigned int protoff
,
50 struct ipv6_opt_hdr _optsh
;
51 const struct ipv6_opt_hdr
*oh
;
52 const struct ip6t_opts
*optinfo
= matchinfo
;
55 unsigned int hdrlen
= 0;
59 const u_int8_t
*tp
= NULL
;
60 const u_int8_t
*lp
= NULL
;
64 err
= ipv6_find_hdr(skb
, &ptr
, match
->data
, NULL
);
71 oh
= skb_header_pointer(skb
, ptr
, sizeof(_optsh
), &_optsh
);
77 hdrlen
= ipv6_optlen(oh
);
78 if (skb
->len
- ptr
< hdrlen
) {
79 /* Packet smaller than it's length field */
83 pr_debug("IPv6 OPTS LEN %u %u ", hdrlen
, oh
->hdrlen
);
85 pr_debug("len %02X %04X %02X ",
86 optinfo
->hdrlen
, hdrlen
,
87 (!(optinfo
->flags
& IP6T_OPTS_LEN
) ||
88 ((optinfo
->hdrlen
== hdrlen
) ^
89 !!(optinfo
->invflags
& IP6T_OPTS_INV_LEN
))));
92 (!(optinfo
->flags
& IP6T_OPTS_LEN
) ||
93 ((optinfo
->hdrlen
== hdrlen
) ^
94 !!(optinfo
->invflags
& IP6T_OPTS_INV_LEN
)));
98 if (!(optinfo
->flags
& IP6T_OPTS_OPTS
)) {
100 } else if (optinfo
->flags
& IP6T_OPTS_NSTRICT
) {
101 pr_debug("Not strict - not implemented");
104 pr_debug("#%d ", optinfo
->optsnr
);
105 for (temp
= 0; temp
< optinfo
->optsnr
; temp
++) {
106 /* type field exists ? */
109 tp
= skb_header_pointer(skb
, ptr
, sizeof(_opttype
),
115 if (*tp
!= (optinfo
->opts
[temp
] & 0xFF00) >> 8) {
116 pr_debug("Tbad %02X %02X\n", *tp
,
117 (optinfo
->opts
[temp
] & 0xFF00) >> 8);
126 /* length field exists ? */
129 lp
= skb_header_pointer(skb
, ptr
+ 1,
134 spec_len
= optinfo
->opts
[temp
] & 0x00FF;
136 if (spec_len
!= 0x00FF && spec_len
!= *lp
) {
137 pr_debug("Lbad %02X %04X\n", *lp
,
148 /* Step to the next */
149 pr_debug("len%04X \n", optlen
);
151 if ((ptr
> skb
->len
- optlen
|| hdrlen
< optlen
) &&
152 temp
< optinfo
->optsnr
- 1) {
153 pr_debug("new pointer is too large! \n");
159 if (temp
== optinfo
->optsnr
)
168 /* Called when user tries to insert an entry of this type. */
170 hbh_mt6_check(const char *tablename
, const void *entry
,
171 const struct xt_match
*match
, void *matchinfo
,
172 unsigned int hook_mask
)
174 const struct ip6t_opts
*optsinfo
= matchinfo
;
176 if (optsinfo
->invflags
& ~IP6T_OPTS_INV_MASK
) {
177 pr_debug("ip6t_opts: unknown flags %X\n", optsinfo
->invflags
);
183 static struct xt_match hbh_mt6_reg
[] __read_mostly
= {
188 .matchsize
= sizeof(struct ip6t_opts
),
189 .checkentry
= hbh_mt6_check
,
197 .matchsize
= sizeof(struct ip6t_opts
),
198 .checkentry
= hbh_mt6_check
,
200 .data
= NEXTHDR_DEST
,
204 static int __init
hbh_mt6_init(void)
206 return xt_register_matches(hbh_mt6_reg
, ARRAY_SIZE(hbh_mt6_reg
));
209 static void __exit
hbh_mt6_exit(void)
211 xt_unregister_matches(hbh_mt6_reg
, ARRAY_SIZE(hbh_mt6_reg
));
214 module_init(hbh_mt6_init
);
215 module_exit(hbh_mt6_exit
);