projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 869f37d8 PM |
1 | /* IRC extension for TCP NAT alteration. |
| 2 | * | |
| 3 | * (C) 2000-2001 by Harald Welte <laforge@gnumonks.org> | |
| 4 | * (C) 2004 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation | |
| 5 | * based on a copy of RR's ip_nat_ftp.c | |
| 6 | * | |
| 7 | * This program is free software; you can redistribute it and/or | |
| 8 | * modify it under the terms of the GNU General Public License | |
| 9 | * as published by the Free Software Foundation; either version | |
| 10 | * 2 of the License, or (at your option) any later version. | |
| 11 | */ | |
| 12 | ||
| 13 | #include <linux/module.h> | |
| 14 | #include <linux/moduleparam.h> | |
| 15 | #include <linux/tcp.h> | |
| 16 | #include <linux/kernel.h> | |
| 17 | ||
| 18 | #include <net/netfilter/nf_nat.h> | |
| 19 | #include <net/netfilter/nf_nat_helper.h> | |
| 869f37d8 PM |
20 | #include <net/netfilter/nf_conntrack_helper.h> |
| 21 | #include <net/netfilter/nf_conntrack_expect.h> | |
| 22 | #include <linux/netfilter/nf_conntrack_irc.h> | |
| 23 | ||
| 869f37d8 PM |
24 | MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>"); |
| 25 | MODULE_DESCRIPTION("IRC (DCC) NAT helper"); | |
| 26 | MODULE_LICENSE("GPL"); | |
| 27 | MODULE_ALIAS("ip_nat_irc"); | |
| 28 | ||
| 3db05fea | 29 | static unsigned int help(struct sk_buff *skb, |
| 869f37d8 | 30 | enum ip_conntrack_info ctinfo, |
| 051966c0 | 31 | unsigned int protoff, |
| 869f37d8 PM |
32 | unsigned int matchoff, |
| 33 | unsigned int matchlen, | |
| 34 | struct nf_conntrack_expect *exp) | |
| 35 | { | |
| 36 | char buffer[sizeof("4294967296 65635")]; | |
| 869f37d8 PM |
37 | u_int16_t port; |
| 38 | unsigned int ret; | |
| 39 | ||
| 869f37d8 PM |
40 | /* Reply comes from server. */ |
| 41 | exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port; | |
| 42 | exp->dir = IP_CT_DIR_REPLY; | |
| 43 | exp->expectfn = nf_nat_follow_master; | |
| 44 | ||
| 45 | /* Try to get same port: if not, try to change it. */ | |
| 46 | for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) { | |
| 5b92b61f PNA |
47 | int ret; |
| 48 | ||
| 869f37d8 | 49 | exp->tuple.dst.u.tcp.port = htons(port); |
| 5b92b61f PNA |
50 | ret = nf_ct_expect_related(exp); |
| 51 | if (ret == 0) | |
| 52 | break; | |
| 53 | else if (ret != -EBUSY) { | |
| 54 | port = 0; | |
| 869f37d8 | 55 | break; |
| 5b92b61f | 56 | } |
| 869f37d8 PM |
57 | } |
| 58 | ||
| b20ab9cc PNA |
59 | if (port == 0) { |
| 60 | nf_ct_helper_log(skb, exp->master, "all ports in use"); | |
| 869f37d8 | 61 | return NF_DROP; |
| b20ab9cc | 62 | } |
| 869f37d8 | 63 | |
| 3db05fea | 64 | ret = nf_nat_mangle_tcp_packet(skb, exp->master, ctinfo, |
| 051966c0 | 65 | protoff, matchoff, matchlen, buffer, |
| 869f37d8 | 66 | strlen(buffer)); |
| b20ab9cc PNA |
67 | if (ret != NF_ACCEPT) { |
| 68 | nf_ct_helper_log(skb, exp->master, "cannot mangle packet"); | |
| 6823645d | 69 | nf_ct_unexpect_related(exp); |
| b20ab9cc | 70 | } |
| 869f37d8 PM |
71 | return ret; |
| 72 | } | |
| 73 | ||
| 74 | static void __exit nf_nat_irc_fini(void) | |
| 75 | { | |
| a9b3cd7f | 76 | RCU_INIT_POINTER(nf_nat_irc_hook, NULL); |
| 869f37d8 PM |
77 | synchronize_rcu(); |
| 78 | } | |
| 79 | ||
| 80 | static int __init nf_nat_irc_init(void) | |
| 81 | { | |
| d1332e0a | 82 | BUG_ON(nf_nat_irc_hook != NULL); |
| a9b3cd7f | 83 | RCU_INIT_POINTER(nf_nat_irc_hook, help); |
| 869f37d8 PM |
84 | return 0; |
| 85 | } | |
| 86 | ||
| 87 | /* Prior to 2.6.11, we had a ports param. No longer, but don't break users. */ | |
| 88 | static int warn_set(const char *val, struct kernel_param *kp) | |
| 89 | { | |
| 90 | printk(KERN_INFO KBUILD_MODNAME | |
| 91 | ": kernel >= 2.6.10 only uses 'ports' for conntrack modules\n"); | |
| 92 | return 0; | |
| 93 | } | |
| 94 | module_param_call(ports, warn_set, NULL, NULL, 0); | |
| 95 | ||
| 96 | module_init(nf_nat_irc_init); | |
| 97 | module_exit(nf_nat_irc_fini); |