Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 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, |
| 54 | const void *matchinfo, |
| 55 | int offset, |
| 56 | unsigned int protoff, |
| 57 | int *hotdrop) |
| 58 | { |
| 59 | u16 _ports[2], *pptr; |
| 60 | const struct ip6t_multiport *multiinfo = matchinfo; |
| 61 | |
| 62 | /* Must not be a fragment. */ |
| 63 | if (offset) |
| 64 | return 0; |
| 65 | |
| 66 | /* Must be big enough to read ports (both UDP and TCP have |
| 67 | them at the start). */ |
| 68 | pptr = skb_header_pointer(skb, protoff, sizeof(_ports), &_ports[0]); |
| 69 | if (pptr == NULL) { |
| 70 | /* We've been asked to examine this packet, and we |
| 71 | * can't. Hence, no choice but to drop. |
| 72 | */ |
| 73 | duprintf("ip6t_multiport:" |
| 74 | " Dropping evil offset=0 tinygram.\n"); |
| 75 | *hotdrop = 1; |
| 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | return ports_match(multiinfo->ports, |
| 80 | multiinfo->flags, multiinfo->count, |
| 81 | ntohs(pptr[0]), ntohs(pptr[1])); |
| 82 | } |
| 83 | |
| 84 | /* Called when user tries to insert an entry of this type. */ |
| 85 | static int |
| 86 | checkentry(const char *tablename, |
| 87 | const struct ip6t_ip6 *ip, |
| 88 | void *matchinfo, |
| 89 | unsigned int matchsize, |
| 90 | unsigned int hook_mask) |
| 91 | { |
| 92 | const struct ip6t_multiport *multiinfo = matchinfo; |
| 93 | |
| 94 | if (matchsize != IP6T_ALIGN(sizeof(struct ip6t_multiport))) |
| 95 | return 0; |
| 96 | |
| 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) |
| 100 | && matchsize == IP6T_ALIGN(sizeof(struct ip6t_multiport)) |
| 101 | && (multiinfo->flags == IP6T_MULTIPORT_SOURCE |
| 102 | || multiinfo->flags == IP6T_MULTIPORT_DESTINATION |
| 103 | || multiinfo->flags == IP6T_MULTIPORT_EITHER) |
| 104 | && multiinfo->count <= IP6T_MULTI_PORTS; |
| 105 | } |
| 106 | |
| 107 | static struct ip6t_match multiport_match = { |
| 108 | .name = "multiport", |
| 109 | .match = &match, |
| 110 | .checkentry = &checkentry, |
| 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); |