1 /* Kernel module to match FRAG 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 <linux/netfilter_ipv6/ip6_tables.h>
18 #include <linux/netfilter_ipv6/ip6t_frag.h>
20 MODULE_LICENSE("GPL");
21 MODULE_DESCRIPTION("IPv6 FRAG match");
22 MODULE_AUTHOR("Andras Kis-Szabo <kisza@sch.bme.hu>");
27 #define DEBUGP(format, args...)
30 /* Returns 1 if the id is matched by the range, 0 otherwise */
32 id_match(u_int32_t min
, u_int32_t max
, u_int32_t id
, int invert
)
35 DEBUGP("frag id_match:%c 0x%x <= 0x%x <= 0x%x", invert
? '!' : ' ',
37 r
= (id
>= min
&& id
<= max
) ^ invert
;
38 DEBUGP(" result %s\n", r
? "PASS" : "FAILED");
43 match(const struct sk_buff
*skb
,
44 const struct net_device
*in
,
45 const struct net_device
*out
,
46 const struct xt_match
*match
,
47 const void *matchinfo
,
52 struct frag_hdr _frag
, *fh
;
53 const struct ip6t_frag
*fraginfo
= matchinfo
;
56 if (ipv6_find_hdr(skb
, &ptr
, NEXTHDR_FRAGMENT
, NULL
) < 0)
59 fh
= skb_header_pointer(skb
, ptr
, sizeof(_frag
), &_frag
);
65 DEBUGP("INFO %04X ", fh
->frag_off
);
66 DEBUGP("OFFSET %04X ", ntohs(fh
->frag_off
) & ~0x7);
67 DEBUGP("RES %02X %04X", fh
->reserved
, ntohs(fh
->frag_off
) & 0x6);
68 DEBUGP("MF %04X ", fh
->frag_off
& htons(IP6_MF
));
69 DEBUGP("ID %u %08X\n", ntohl(fh
->identification
),
70 ntohl(fh
->identification
));
72 DEBUGP("IPv6 FRAG id %02X ",
73 (id_match(fraginfo
->ids
[0], fraginfo
->ids
[1],
74 ntohl(fh
->identification
),
75 !!(fraginfo
->invflags
& IP6T_FRAG_INV_IDS
))));
76 DEBUGP("res %02X %02X%04X %02X ",
77 (fraginfo
->flags
& IP6T_FRAG_RES
), fh
->reserved
,
78 ntohs(fh
->frag_off
) & 0x6,
79 !((fraginfo
->flags
& IP6T_FRAG_RES
)
80 && (fh
->reserved
|| (ntohs(fh
->frag_off
) & 0x06))));
81 DEBUGP("first %02X %02X %02X ",
82 (fraginfo
->flags
& IP6T_FRAG_FST
),
83 ntohs(fh
->frag_off
) & ~0x7,
84 !((fraginfo
->flags
& IP6T_FRAG_FST
)
85 && (ntohs(fh
->frag_off
) & ~0x7)));
86 DEBUGP("mf %02X %02X %02X ",
87 (fraginfo
->flags
& IP6T_FRAG_MF
),
88 ntohs(fh
->frag_off
) & IP6_MF
,
89 !((fraginfo
->flags
& IP6T_FRAG_MF
)
90 && !((ntohs(fh
->frag_off
) & IP6_MF
))));
91 DEBUGP("last %02X %02X %02X\n",
92 (fraginfo
->flags
& IP6T_FRAG_NMF
),
93 ntohs(fh
->frag_off
) & IP6_MF
,
94 !((fraginfo
->flags
& IP6T_FRAG_NMF
)
95 && (ntohs(fh
->frag_off
) & IP6_MF
)));
99 (id_match(fraginfo
->ids
[0], fraginfo
->ids
[1],
100 ntohl(fh
->identification
),
101 !!(fraginfo
->invflags
& IP6T_FRAG_INV_IDS
)))
103 !((fraginfo
->flags
& IP6T_FRAG_RES
)
104 && (fh
->reserved
|| (ntohs(fh
->frag_off
) & 0x6)))
106 !((fraginfo
->flags
& IP6T_FRAG_FST
)
107 && (ntohs(fh
->frag_off
) & ~0x7))
109 !((fraginfo
->flags
& IP6T_FRAG_MF
)
110 && !(ntohs(fh
->frag_off
) & IP6_MF
))
112 !((fraginfo
->flags
& IP6T_FRAG_NMF
)
113 && (ntohs(fh
->frag_off
) & IP6_MF
));
116 /* Called when user tries to insert an entry of this type. */
118 checkentry(const char *tablename
,
120 const struct xt_match
*match
,
122 unsigned int matchinfosize
,
123 unsigned int hook_mask
)
125 const struct ip6t_frag
*fraginfo
= matchinfo
;
127 if (fraginfo
->invflags
& ~IP6T_FRAG_INV_MASK
) {
128 DEBUGP("ip6t_frag: unknown flags %X\n", fraginfo
->invflags
);
134 static struct ip6t_match frag_match
= {
137 .matchsize
= sizeof(struct ip6t_frag
),
138 .checkentry
= checkentry
,
142 static int __init
ip6t_frag_init(void)
144 return ip6t_register_match(&frag_match
);
147 static void __exit
ip6t_frag_fini(void)
149 ip6t_unregister_match(&frag_match
);
152 module_init(ip6t_frag_init
);
153 module_exit(ip6t_frag_fini
);