]>
git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - net/netfilter/xt_u32.c
2 * xt_u32 - kernel module to match u32 packet content
4 * Original author: Don Cohen <don@isis.cs3-inc.com>
5 * © Jan Engelhardt <jengelh@gmx.de>, 2007
8 #include <linux/module.h>
9 #include <linux/moduleparam.h>
10 #include <linux/spinlock.h>
11 #include <linux/skbuff.h>
12 #include <linux/types.h>
13 #include <linux/netfilter/x_tables.h>
14 #include <linux/netfilter/xt_u32.h>
16 static bool u32_match_it(const struct xt_u32
*data
,
17 const struct sk_buff
*skb
)
19 const struct xt_u32_test
*ct
;
31 * Small example: "0 >> 28 == 4 && 8 & 0xFF0000 >> 16 = 6, 17"
32 * (=IPv4 and (TCP or UDP)). Outer loop runs over the "&&" operands.
34 for (testind
= 0; testind
< data
->ntests
; ++testind
) {
35 ct
= &data
->tests
[testind
];
37 pos
= ct
->location
[0].number
;
39 if (skb
->len
< 4 || pos
> skb
->len
- 4)
42 ret
= skb_copy_bits(skb
, pos
, &n
, sizeof(n
));
47 /* Inner loop runs over "&", "<<", ">>" and "@" operands */
48 for (i
= 1; i
< nnums
; ++i
) {
49 u_int32_t number
= ct
->location
[i
].number
;
50 switch (ct
->location
[i
].nextop
) {
65 if (at
+ 4 < at
|| skb
->len
< at
+ 4 ||
66 pos
> skb
->len
- at
- 4)
69 ret
= skb_copy_bits(skb
, at
+ pos
, &n
,
77 /* Run over the "," and ":" operands */
79 for (i
= 0; i
< nvals
; ++i
)
80 if (ct
->value
[i
].min
<= val
&& val
<= ct
->value
[i
].max
)
90 static bool u32_match(const struct sk_buff
*skb
,
91 const struct net_device
*in
,
92 const struct net_device
*out
,
93 const struct xt_match
*match
, const void *matchinfo
,
94 int offset
, unsigned int protoff
, bool *hotdrop
)
96 const struct xt_u32
*data
= matchinfo
;
99 ret
= u32_match_it(data
, skb
);
100 return ret
^ data
->invert
;
103 static struct xt_match u32_reg
[] __read_mostly
= {
108 .matchsize
= sizeof(struct xt_u32
),
115 .matchsize
= sizeof(struct xt_u32
),
120 static int __init
xt_u32_init(void)
122 return xt_register_matches(u32_reg
, ARRAY_SIZE(u32_reg
));
125 static void __exit
xt_u32_exit(void)
127 xt_unregister_matches(u32_reg
, ARRAY_SIZE(u32_reg
));
130 module_init(xt_u32_init
);
131 module_exit(xt_u32_exit
);
132 MODULE_AUTHOR("Jan Engelhardt <jengelh@gmx.de>");
133 MODULE_DESCRIPTION("netfilter u32 match module");
134 MODULE_LICENSE("GPL");
135 MODULE_ALIAS("ipt_u32");
136 MODULE_ALIAS("ip6t_u32");