Commit | Line | Data |
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1da177e4 LT |
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 | ||
21 | MODULE_LICENSE("GPL"); | |
22 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
23 | MODULE_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. */ | |
32 | static inline int | |
33 | ports_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 | ||
50 | static int | |
51 | match(const struct sk_buff *skb, | |
52 | const struct net_device *in, | |
53 | const struct net_device *out, | |
c4986734 | 54 | const struct xt_match *match, |
1da177e4 LT |
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. */ | |
86 | static int | |
87 | checkentry(const char *tablename, | |
2e4e6a17 | 88 | const void *info, |
c4986734 | 89 | const struct xt_match *match, |
1da177e4 LT |
90 | void *matchinfo, |
91 | unsigned int matchsize, | |
92 | unsigned int hook_mask) | |
93 | { | |
2e4e6a17 | 94 | const struct ip6t_ip6 *ip = info; |
1da177e4 LT |
95 | const struct ip6t_multiport *multiinfo = matchinfo; |
96 | ||
1da177e4 LT |
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) | |
1da177e4 LT |
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 | ||
106 | static struct ip6t_match multiport_match = { | |
107 | .name = "multiport", | |
7f939713 PM |
108 | .match = match, |
109 | .matchsize = sizeof(struct ip6t_multiport), | |
110 | .checkentry = checkentry, | |
1da177e4 LT |
111 | .me = THIS_MODULE, |
112 | }; | |
113 | ||
114 | static int __init init(void) | |
115 | { | |
116 | return ip6t_register_match(&multiport_match); | |
117 | } | |
118 | ||
119 | static void __exit fini(void) | |
120 | { | |
121 | ip6t_unregister_match(&multiport_match); | |
122 | } | |
123 | ||
124 | module_init(init); | |
125 | module_exit(fini); |