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 void *matchinfo
,
63 struct ipv6_opt_hdr _optsh
, *oh
;
64 const struct ip6t_opts
*optinfo
= matchinfo
;
69 unsigned int hdrlen
= 0;
71 u8 _opttype
, *tp
= NULL
;
72 u8 _optlen
, *lp
= NULL
;
75 /* type of the 1st exthdr */
76 nexthdr
= skb
->nh
.ipv6h
->nexthdr
;
77 /* pointer to the 1st exthdr */
78 ptr
= sizeof(struct ipv6hdr
);
79 /* available length */
83 while (ip6t_ext_hdr(nexthdr
)) {
84 struct ipv6_opt_hdr _hdr
, *hp
;
86 DEBUGP("ipv6_opts header iteration \n");
88 /* Is there enough space for the next ext header? */
89 if (len
< (int)sizeof(struct ipv6_opt_hdr
))
91 /* No more exthdr -> evaluate */
92 if (nexthdr
== NEXTHDR_NONE
) {
96 if (nexthdr
== NEXTHDR_ESP
) {
100 hp
= skb_header_pointer(skb
, ptr
, sizeof(_hdr
), &_hdr
);
103 /* Calculate the header length */
104 if (nexthdr
== NEXTHDR_FRAGMENT
) {
106 } else if (nexthdr
== NEXTHDR_AUTH
)
107 hdrlen
= (hp
->hdrlen
+2)<<2;
109 hdrlen
= ipv6_optlen(hp
);
111 /* OPTS -> evaluate */
113 if (nexthdr
== NEXTHDR_HOP
) {
114 temp
|= MASK_HOPOPTS
;
116 if (nexthdr
== NEXTHDR_DEST
) {
117 temp
|= MASK_DSTOPTS
;
126 case NEXTHDR_ROUTING
:
127 case NEXTHDR_FRAGMENT
:
132 DEBUGP("ipv6_opts match: unknown nextheader %u\n",nexthdr
);
137 nexthdr
= hp
->nexthdr
;
140 if ( ptr
> skb
->len
) {
141 DEBUGP("ipv6_opts: new pointer is too large! \n");
146 /* OPTIONS header not found */
148 if ( temp
!= MASK_HOPOPTS
) return 0;
150 if ( temp
!= MASK_DSTOPTS
) return 0;
153 if (len
< (int)sizeof(struct ipv6_opt_hdr
)){
159 /* Packet smaller than it's length field */
163 oh
= skb_header_pointer(skb
, ptr
, sizeof(_optsh
), &_optsh
);
166 DEBUGP("IPv6 OPTS LEN %u %u ", hdrlen
, oh
->hdrlen
);
168 DEBUGP("len %02X %04X %02X ",
169 optinfo
->hdrlen
, hdrlen
,
170 (!(optinfo
->flags
& IP6T_OPTS_LEN
) ||
171 ((optinfo
->hdrlen
== hdrlen
) ^
172 !!(optinfo
->invflags
& IP6T_OPTS_INV_LEN
))));
176 (!(optinfo
->flags
& IP6T_OPTS_LEN
) ||
177 ((optinfo
->hdrlen
== hdrlen
) ^
178 !!(optinfo
->invflags
& IP6T_OPTS_INV_LEN
)));
182 if ( !(optinfo
->flags
& IP6T_OPTS_OPTS
) ){
184 } else if (optinfo
->flags
& IP6T_OPTS_NSTRICT
) {
185 DEBUGP("Not strict - not implemented");
188 DEBUGP("#%d ",optinfo
->optsnr
);
189 for(temp
=0; temp
<optinfo
->optsnr
; temp
++){
190 /* type field exists ? */
193 tp
= skb_header_pointer(skb
, ptr
, sizeof(_opttype
),
199 if (*tp
!= (optinfo
->opts
[temp
] & 0xFF00)>>8){
200 DEBUGP("Tbad %02X %02X\n",
202 (optinfo
->opts
[temp
] & 0xFF00)>>8);
211 /* length field exists ? */
214 lp
= skb_header_pointer(skb
, ptr
+ 1,
219 spec_len
= optinfo
->opts
[temp
] & 0x00FF;
221 if (spec_len
!= 0x00FF && spec_len
!= *lp
) {
222 DEBUGP("Lbad %02X %04X\n", *lp
,
233 /* Step to the next */
234 DEBUGP("len%04X \n", optlen
);
236 if ((ptr
> skb
->len
- optlen
|| hdrlen
< optlen
) &&
237 (temp
< optinfo
->optsnr
- 1)) {
238 DEBUGP("new pointer is too large! \n");
244 if (temp
== optinfo
->optsnr
)
252 /* Called when user tries to insert an entry of this type. */
254 checkentry(const char *tablename
,
255 const struct ip6t_ip6
*ip
,
257 unsigned int matchinfosize
,
258 unsigned int hook_mask
)
260 const struct ip6t_opts
*optsinfo
= matchinfo
;
262 if (matchinfosize
!= IP6T_ALIGN(sizeof(struct ip6t_opts
))) {
263 DEBUGP("ip6t_opts: matchsize %u != %u\n",
264 matchinfosize
, IP6T_ALIGN(sizeof(struct ip6t_opts
)));
267 if (optsinfo
->invflags
& ~IP6T_OPTS_INV_MASK
) {
268 DEBUGP("ip6t_opts: unknown flags %X\n",
276 static struct ip6t_match opts_match
= {
283 .checkentry
= &checkentry
,
287 static int __init
init(void)
289 return ip6t_register_match(&opts_match
);
292 static void __exit
cleanup(void)
294 ip6t_unregister_match(&opts_match
);
298 module_exit(cleanup
);