[NETFILTER]: x_tables: add xt_{match,target} arguments to match/target functions
[deliverable/linux.git] / net / ipv6 / netfilter / ip6t_multiport.c
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1/* Kernel module to match one of a list of TCP/UDP ports: ports are in
2 the same place so we can treat them as equal. */
3
4/* (C) 1999-2001 Paul `Rusty' Russell
5 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/module.h>
13#include <linux/types.h>
14#include <linux/udp.h>
15#include <linux/skbuff.h>
16#include <linux/in.h>
17
18#include <linux/netfilter_ipv6/ip6t_multiport.h>
19#include <linux/netfilter_ipv6/ip6_tables.h>
20
21MODULE_LICENSE("GPL");
22MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
23MODULE_DESCRIPTION("ip6tables match for multiple ports");
24
25#if 0
26#define duprintf(format, args...) printk(format , ## args)
27#else
28#define duprintf(format, args...)
29#endif
30
31/* Returns 1 if the port is matched by the test, 0 otherwise. */
32static inline int
33ports_match(const u_int16_t *portlist, enum ip6t_multiport_flags flags,
34 u_int8_t count, u_int16_t src, u_int16_t dst)
35{
36 unsigned int i;
37 for (i=0; i<count; i++) {
38 if (flags != IP6T_MULTIPORT_DESTINATION
39 && portlist[i] == src)
40 return 1;
41
42 if (flags != IP6T_MULTIPORT_SOURCE
43 && portlist[i] == dst)
44 return 1;
45 }
46
47 return 0;
48}
49
50static int
51match(const struct sk_buff *skb,
52 const struct net_device *in,
53 const struct net_device *out,
c4986734 54 const struct xt_match *match,
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55 const void *matchinfo,
56 int offset,
57 unsigned int protoff,
58 int *hotdrop)
59{
60 u16 _ports[2], *pptr;
61 const struct ip6t_multiport *multiinfo = matchinfo;
62
63 /* Must not be a fragment. */
64 if (offset)
65 return 0;
66
67 /* Must be big enough to read ports (both UDP and TCP have
68 them at the start). */
69 pptr = skb_header_pointer(skb, protoff, sizeof(_ports), &_ports[0]);
70 if (pptr == NULL) {
71 /* We've been asked to examine this packet, and we
72 * can't. Hence, no choice but to drop.
73 */
74 duprintf("ip6t_multiport:"
75 " Dropping evil offset=0 tinygram.\n");
76 *hotdrop = 1;
77 return 0;
78 }
79
80 return ports_match(multiinfo->ports,
81 multiinfo->flags, multiinfo->count,
82 ntohs(pptr[0]), ntohs(pptr[1]));
83}
84
85/* Called when user tries to insert an entry of this type. */
86static int
87checkentry(const char *tablename,
2e4e6a17 88 const void *info,
c4986734 89 const struct xt_match *match,
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90 void *matchinfo,
91 unsigned int matchsize,
92 unsigned int hook_mask)
93{
2e4e6a17 94 const struct ip6t_ip6 *ip = info;
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95 const struct ip6t_multiport *multiinfo = matchinfo;
96
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97 /* Must specify proto == TCP/UDP, no unknown flags or bad count */
98 return (ip->proto == IPPROTO_TCP || ip->proto == IPPROTO_UDP)
99 && !(ip->invflags & IP6T_INV_PROTO)
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100 && (multiinfo->flags == IP6T_MULTIPORT_SOURCE
101 || multiinfo->flags == IP6T_MULTIPORT_DESTINATION
102 || multiinfo->flags == IP6T_MULTIPORT_EITHER)
103 && multiinfo->count <= IP6T_MULTI_PORTS;
104}
105
106static struct ip6t_match multiport_match = {
107 .name = "multiport",
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108 .match = match,
109 .matchsize = sizeof(struct ip6t_multiport),
110 .checkentry = checkentry,
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111 .me = THIS_MODULE,
112};
113
114static int __init init(void)
115{
116 return ip6t_register_match(&multiport_match);
117}
118
119static void __exit fini(void)
120{
121 ip6t_unregister_match(&multiport_match);
122}
123
124module_init(init);
125module_exit(fini);
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