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("IPv6 opts 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 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 ipv6_opt_hdr _optsh
;
55 const struct ipv6_opt_hdr
*oh
;
56 const struct ip6t_opts
*optinfo
= matchinfo
;
59 unsigned int hdrlen
= 0;
63 const u_int8_t
*tp
= NULL
;
64 const u_int8_t
*lp
= NULL
;
68 err
= ipv6_find_hdr(skb
, &ptr
, match
->data
, NULL
);
75 oh
= skb_header_pointer(skb
, ptr
, sizeof(_optsh
), &_optsh
);
81 hdrlen
= ipv6_optlen(oh
);
82 if (skb
->len
- ptr
< hdrlen
) {
83 /* Packet smaller than it's length field */
87 pr_debug("IPv6 OPTS LEN %u %u ", hdrlen
, oh
->hdrlen
);
89 pr_debug("len %02X %04X %02X ",
90 optinfo
->hdrlen
, hdrlen
,
91 (!(optinfo
->flags
& IP6T_OPTS_LEN
) ||
92 ((optinfo
->hdrlen
== hdrlen
) ^
93 !!(optinfo
->invflags
& IP6T_OPTS_INV_LEN
))));
96 (!(optinfo
->flags
& IP6T_OPTS_LEN
) ||
97 ((optinfo
->hdrlen
== hdrlen
) ^
98 !!(optinfo
->invflags
& IP6T_OPTS_INV_LEN
)));
102 if (!(optinfo
->flags
& IP6T_OPTS_OPTS
)) {
104 } else if (optinfo
->flags
& IP6T_OPTS_NSTRICT
) {
105 pr_debug("Not strict - not implemented");
108 pr_debug("#%d ", optinfo
->optsnr
);
109 for (temp
= 0; temp
< optinfo
->optsnr
; temp
++) {
110 /* type field exists ? */
113 tp
= skb_header_pointer(skb
, ptr
, sizeof(_opttype
),
119 if (*tp
!= (optinfo
->opts
[temp
] & 0xFF00) >> 8) {
120 pr_debug("Tbad %02X %02X\n", *tp
,
121 (optinfo
->opts
[temp
] & 0xFF00) >> 8);
130 /* length field exists ? */
133 lp
= skb_header_pointer(skb
, ptr
+ 1,
138 spec_len
= optinfo
->opts
[temp
] & 0x00FF;
140 if (spec_len
!= 0x00FF && spec_len
!= *lp
) {
141 pr_debug("Lbad %02X %04X\n", *lp
,
152 /* Step to the next */
153 pr_debug("len%04X \n", optlen
);
155 if ((ptr
> skb
->len
- optlen
|| hdrlen
< optlen
) &&
156 temp
< optinfo
->optsnr
- 1) {
157 pr_debug("new pointer is too large! \n");
163 if (temp
== optinfo
->optsnr
)
172 /* Called when user tries to insert an entry of this type. */
174 checkentry(const char *tablename
,
176 const struct xt_match
*match
,
178 unsigned int hook_mask
)
180 const struct ip6t_opts
*optsinfo
= matchinfo
;
182 if (optsinfo
->invflags
& ~IP6T_OPTS_INV_MASK
) {
183 pr_debug("ip6t_opts: unknown flags %X\n", optsinfo
->invflags
);
189 static struct xt_match opts_match
[] __read_mostly
= {
194 .matchsize
= sizeof(struct ip6t_opts
),
195 .checkentry
= checkentry
,
203 .matchsize
= sizeof(struct ip6t_opts
),
204 .checkentry
= checkentry
,
206 .data
= NEXTHDR_DEST
,
210 static int __init
ip6t_hbh_init(void)
212 return xt_register_matches(opts_match
, ARRAY_SIZE(opts_match
));
215 static void __exit
ip6t_hbh_fini(void)
217 xt_unregister_matches(opts_match
, ARRAY_SIZE(opts_match
));
220 module_init(ip6t_hbh_init
);
221 module_exit(ip6t_hbh_fini
);