Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* iptables module to match on related connections */ |
| 2 | /* |
| 3 | * (C) 2001 Martin Josefsson <gandalf@wlug.westbo.se> |
| 4 | * |
| 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. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | */ |
| 9 | |
| 10 | #include <linux/module.h> |
| 11 | #include <linux/skbuff.h> |
| 12 | #include <linux/netfilter.h> |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 13 | #include <net/netfilter/nf_conntrack.h> |
| 14 | #include <net/netfilter/nf_conntrack_core.h> |
| 15 | #include <net/netfilter/nf_conntrack_helper.h> |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 16 | #include <linux/netfilter/x_tables.h> |
| 17 | #include <linux/netfilter/xt_helper.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | |
| 19 | MODULE_LICENSE("GPL"); |
| 20 | MODULE_AUTHOR("Martin Josefsson <gandalf@netfilter.org>"); |
| 21 | MODULE_DESCRIPTION("iptables helper match module"); |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 22 | MODULE_ALIAS("ipt_helper"); |
| 23 | MODULE_ALIAS("ip6t_helper"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | |
| 25 | #if 0 |
| 26 | #define DEBUGP printk |
| 27 | #else |
| 28 | #define DEBUGP(format, args...) |
| 29 | #endif |
| 30 | |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 31 | static bool |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 32 | match(const struct sk_buff *skb, |
| 33 | const struct net_device *in, |
| 34 | const struct net_device *out, |
Patrick McHardy | c498673 | 2006-03-20 18:02:56 -0800 | [diff] [blame] | 35 | const struct xt_match *match, |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 36 | const void *matchinfo, |
| 37 | int offset, |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 38 | unsigned int protoff, |
Jan Engelhardt | cff533a | 2007-07-07 22:15:12 -0700 | [diff] [blame] | 39 | bool *hotdrop) |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 40 | { |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 41 | const struct xt_helper_info *info = matchinfo; |
Jan Engelhardt | a47362a | 2007-07-07 22:16:55 -0700 | [diff] [blame^] | 42 | const struct nf_conn *ct; |
| 43 | const struct nf_conn_help *master_help; |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 44 | enum ip_conntrack_info ctinfo; |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 45 | bool ret = info->invert; |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 46 | |
Jan Engelhardt | a47362a | 2007-07-07 22:16:55 -0700 | [diff] [blame^] | 47 | ct = nf_ct_get(skb, &ctinfo); |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 48 | if (!ct) { |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 49 | DEBUGP("xt_helper: Eek! invalid conntrack?\n"); |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 50 | return ret; |
| 51 | } |
| 52 | |
| 53 | if (!ct->master) { |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 54 | DEBUGP("xt_helper: conntrack %p has no master\n", ct); |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 55 | return ret; |
| 56 | } |
| 57 | |
| 58 | read_lock_bh(&nf_conntrack_lock); |
Harald Welte | dc808fe | 2006-03-20 17:56:32 -0800 | [diff] [blame] | 59 | master_help = nfct_help(ct->master); |
| 60 | if (!master_help || !master_help->helper) { |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 61 | DEBUGP("xt_helper: master ct %p has no helper\n", |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 62 | exp->expectant); |
| 63 | goto out_unlock; |
| 64 | } |
| 65 | |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 66 | DEBUGP("master's name = %s , info->name = %s\n", |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 67 | ct->master->helper->name, info->name); |
| 68 | |
| 69 | if (info->name[0] == '\0') |
Jan Engelhardt | 1d93a9c | 2007-07-07 22:15:35 -0700 | [diff] [blame] | 70 | ret = !ret; |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 71 | else |
Harald Welte | dc808fe | 2006-03-20 17:56:32 -0800 | [diff] [blame] | 72 | ret ^= !strncmp(master_help->helper->name, info->name, |
YOSHIFUJI Hideaki | 601e68e | 2007-02-12 11:15:49 -0800 | [diff] [blame] | 73 | strlen(master_help->helper->name)); |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 74 | out_unlock: |
| 75 | read_unlock_bh(&nf_conntrack_lock); |
| 76 | return ret; |
| 77 | } |
Yasuyuki Kozakai | 9fb9cbb | 2005-11-09 16:38:16 -0800 | [diff] [blame] | 78 | |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 79 | static bool check(const char *tablename, |
| 80 | const void *inf, |
| 81 | const struct xt_match *match, |
| 82 | void *matchinfo, |
| 83 | unsigned int hook_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | { |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 85 | struct xt_helper_info *info = matchinfo; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | |
Pablo Neira Ayuso | b9f78f9 | 2006-03-22 13:56:08 -0800 | [diff] [blame] | 87 | if (nf_ct_l3proto_try_module_get(match->family) < 0) { |
Yasuyuki Kozakai | fe0b929 | 2006-12-12 00:28:40 -0800 | [diff] [blame] | 88 | printk(KERN_WARNING "can't load conntrack support for " |
Pablo Neira Ayuso | b9f78f9 | 2006-03-22 13:56:08 -0800 | [diff] [blame] | 89 | "proto=%d\n", match->family); |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 90 | return false; |
Pablo Neira Ayuso | b9f78f9 | 2006-03-22 13:56:08 -0800 | [diff] [blame] | 91 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | info->name[29] = '\0'; |
Jan Engelhardt | ccb79bd | 2007-07-07 22:16:00 -0700 | [diff] [blame] | 93 | return true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | } |
| 95 | |
Pablo Neira Ayuso | b9f78f9 | 2006-03-22 13:56:08 -0800 | [diff] [blame] | 96 | static void |
Patrick McHardy | efa7416 | 2006-08-22 00:36:37 -0700 | [diff] [blame] | 97 | destroy(const struct xt_match *match, void *matchinfo) |
Pablo Neira Ayuso | b9f78f9 | 2006-03-22 13:56:08 -0800 | [diff] [blame] | 98 | { |
Pablo Neira Ayuso | b9f78f9 | 2006-03-22 13:56:08 -0800 | [diff] [blame] | 99 | nf_ct_l3proto_module_put(match->family); |
Pablo Neira Ayuso | b9f78f9 | 2006-03-22 13:56:08 -0800 | [diff] [blame] | 100 | } |
| 101 | |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 102 | static struct xt_match xt_helper_match[] = { |
| 103 | { |
| 104 | .name = "helper", |
| 105 | .family = AF_INET, |
| 106 | .checkentry = check, |
| 107 | .match = match, |
| 108 | .destroy = destroy, |
| 109 | .matchsize = sizeof(struct xt_helper_info), |
| 110 | .me = THIS_MODULE, |
| 111 | }, |
| 112 | { |
| 113 | .name = "helper", |
| 114 | .family = AF_INET6, |
| 115 | .checkentry = check, |
| 116 | .match = match, |
| 117 | .destroy = destroy, |
| 118 | .matchsize = sizeof(struct xt_helper_info), |
| 119 | .me = THIS_MODULE, |
| 120 | }, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | }; |
| 122 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 123 | static int __init xt_helper_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | { |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 125 | return xt_register_matches(xt_helper_match, |
| 126 | ARRAY_SIZE(xt_helper_match)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 127 | } |
| 128 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 129 | static void __exit xt_helper_fini(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | { |
Patrick McHardy | 4470bbc | 2006-08-22 00:34:04 -0700 | [diff] [blame] | 131 | xt_unregister_matches(xt_helper_match, ARRAY_SIZE(xt_helper_match)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | } |
| 133 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 134 | module_init(xt_helper_init); |
| 135 | module_exit(xt_helper_fini); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | |