1 /* IRC extension for TCP NAT alteration.
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
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.
13 #include <linux/module.h>
14 #include <linux/moduleparam.h>
15 #include <linux/tcp.h>
16 #include <linux/kernel.h>
18 #include <net/netfilter/nf_nat.h>
19 #include <net/netfilter/nf_nat_helper.h>
20 #include <net/netfilter/nf_nat_rule.h>
21 #include <net/netfilter/nf_conntrack_helper.h>
22 #include <net/netfilter/nf_conntrack_expect.h>
23 #include <linux/netfilter/nf_conntrack_irc.h>
28 #define DEBUGP(format, args...)
31 MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
32 MODULE_DESCRIPTION("IRC (DCC) NAT helper");
33 MODULE_LICENSE("GPL");
34 MODULE_ALIAS("ip_nat_irc");
36 static unsigned int help(struct sk_buff **pskb,
37 enum ip_conntrack_info ctinfo,
38 unsigned int matchoff,
39 unsigned int matchlen,
40 struct nf_conntrack_expect *exp)
42 char buffer[sizeof("4294967296 65635")];
47 DEBUGP("IRC_NAT: info (seq %u + %u) in %u\n",
48 expect->seq, exp_irc_info->len, ntohl(tcph->seq));
50 /* Reply comes from server. */
51 exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
52 exp->dir = IP_CT_DIR_REPLY;
53 exp->expectfn = nf_nat_follow_master;
55 /* Try to get same port: if not, try to change it. */
56 for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) {
57 exp->tuple.dst.u.tcp.port = htons(port);
58 if (nf_conntrack_expect_related(exp) == 0)
65 ip = ntohl(exp->master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip);
66 sprintf(buffer, "%u %u", ip, port);
67 DEBUGP("nf_nat_irc: inserting '%s' == %u.%u.%u.%u, port %u\n",
68 buffer, NIPQUAD(ip), port);
70 ret = nf_nat_mangle_tcp_packet(pskb, exp->master, ctinfo,
71 matchoff, matchlen, buffer,
74 nf_conntrack_unexpect_related(exp);
78 static void __exit nf_nat_irc_fini(void)
80 rcu_assign_pointer(nf_nat_irc_hook, NULL);
84 static int __init nf_nat_irc_init(void)
86 BUG_ON(rcu_dereference(nf_nat_irc_hook));
87 rcu_assign_pointer(nf_nat_irc_hook, help);
91 /* Prior to 2.6.11, we had a ports param. No longer, but don't break users. */
92 static int warn_set(const char *val, struct kernel_param *kp)
94 printk(KERN_INFO KBUILD_MODNAME
95 ": kernel >= 2.6.10 only uses 'ports' for conntrack modules\n");
98 module_param_call(ports, warn_set, NULL, NULL, 0);
100 module_init(nf_nat_irc_init);
101 module_exit(nf_nat_irc_fini);