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_ipv6/ip6_tables.h>
20 #include <linux/netfilter_ipv6/ip6t_opts.h>
24 MODULE_LICENSE("GPL");
26 MODULE_DESCRIPTION("IPv6 HbH match");
28 MODULE_DESCRIPTION("IPv6 DST match");
30 MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
35 #define DEBUGP(format, args...)
41 * 1 -> must drop the packet
42 * 2 -> send ICMP PARM PROB regardless and drop packet
43 * 3 -> Send ICMP if not a multicast address and drop packet
46 * 1 -> can change the routing
48 * 0 -> Pad1 (only 1 byte!)
49 * 1 -> PadN LENGTH info (total length = length + 2)
50 * C0 | 2 -> JUMBO 4 x x x x ( xxxx > 64k )
55 match(const struct sk_buff
*skb
,
56 const struct net_device
*in
,
57 const struct net_device
*out
,
58 const struct xt_match
*match
,
59 const void *matchinfo
,
64 struct ipv6_opt_hdr _optsh
, *oh
;
65 const struct ip6t_opts
*optinfo
= matchinfo
;
68 unsigned int hdrlen
= 0;
70 u8 _opttype
, *tp
= NULL
;
71 u8 _optlen
, *lp
= NULL
;
75 if (ipv6_find_hdr(skb
, &ptr
, NEXTHDR_HOP
, NULL
) < 0)
77 if (ipv6_find_hdr(skb
, &ptr
, NEXTHDR_DEST
, NULL
) < 0)
81 oh
= skb_header_pointer(skb
, ptr
, sizeof(_optsh
), &_optsh
);
87 hdrlen
= ipv6_optlen(oh
);
88 if (skb
->len
- ptr
< hdrlen
) {
89 /* Packet smaller than it's length field */
93 DEBUGP("IPv6 OPTS LEN %u %u ", hdrlen
, oh
->hdrlen
);
95 DEBUGP("len %02X %04X %02X ",
96 optinfo
->hdrlen
, hdrlen
,
97 (!(optinfo
->flags
& IP6T_OPTS_LEN
) ||
98 ((optinfo
->hdrlen
== hdrlen
) ^
99 !!(optinfo
->invflags
& IP6T_OPTS_INV_LEN
))));
101 ret
= (oh
!= NULL
) &&
102 (!(optinfo
->flags
& IP6T_OPTS_LEN
) ||
103 ((optinfo
->hdrlen
== hdrlen
) ^
104 !!(optinfo
->invflags
& IP6T_OPTS_INV_LEN
)));
108 if (!(optinfo
->flags
& IP6T_OPTS_OPTS
)) {
110 } else if (optinfo
->flags
& IP6T_OPTS_NSTRICT
) {
111 DEBUGP("Not strict - not implemented");
114 DEBUGP("#%d ", optinfo
->optsnr
);
115 for (temp
= 0; temp
< optinfo
->optsnr
; temp
++) {
116 /* type field exists ? */
119 tp
= skb_header_pointer(skb
, ptr
, sizeof(_opttype
),
125 if (*tp
!= (optinfo
->opts
[temp
] & 0xFF00) >> 8) {
126 DEBUGP("Tbad %02X %02X\n",
128 (optinfo
->opts
[temp
] & 0xFF00) >> 8);
137 /* length field exists ? */
140 lp
= skb_header_pointer(skb
, ptr
+ 1,
145 spec_len
= optinfo
->opts
[temp
] & 0x00FF;
147 if (spec_len
!= 0x00FF && spec_len
!= *lp
) {
148 DEBUGP("Lbad %02X %04X\n", *lp
,
159 /* Step to the next */
160 DEBUGP("len%04X \n", optlen
);
162 if ((ptr
> skb
->len
- optlen
|| hdrlen
< optlen
) &&
163 (temp
< optinfo
->optsnr
- 1)) {
164 DEBUGP("new pointer is too large! \n");
170 if (temp
== optinfo
->optsnr
)
179 /* Called when user tries to insert an entry of this type. */
181 checkentry(const char *tablename
,
183 const struct xt_match
*match
,
185 unsigned int matchinfosize
,
186 unsigned int hook_mask
)
188 const struct ip6t_opts
*optsinfo
= matchinfo
;
190 if (optsinfo
->invflags
& ~IP6T_OPTS_INV_MASK
) {
191 DEBUGP("ip6t_opts: unknown flags %X\n", optsinfo
->invflags
);
197 static struct ip6t_match opts_match
= {
204 .matchsize
= sizeof(struct ip6t_opts
),
205 .checkentry
= checkentry
,
209 static int __init
ip6t_dst_init(void)
211 return ip6t_register_match(&opts_match
);
214 static void __exit
ip6t_dst_fini(void)
216 ip6t_unregister_match(&opts_match
);
219 module_init(ip6t_dst_init
);
220 module_exit(ip6t_dst_fini
);
This page took 0.037372 seconds and 5 git commands to generate.