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>
25 MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
26 MODULE_DESCRIPTION("IRC (DCC) NAT helper");
27 MODULE_LICENSE("GPL");
28 MODULE_ALIAS("ip_nat_irc");
30 static unsigned int help(struct sk_buff
*skb
,
31 enum ip_conntrack_info ctinfo
,
32 unsigned int matchoff
,
33 unsigned int matchlen
,
34 struct nf_conntrack_expect
*exp
)
36 char buffer
[sizeof("4294967296 65635")];
41 /* Reply comes from server. */
42 exp
->saved_proto
.tcp
.port
= exp
->tuple
.dst
.u
.tcp
.port
;
43 exp
->dir
= IP_CT_DIR_REPLY
;
44 exp
->expectfn
= nf_nat_follow_master
;
46 /* Try to get same port: if not, try to change it. */
47 for (port
= ntohs(exp
->saved_proto
.tcp
.port
); port
!= 0; port
++) {
48 exp
->tuple
.dst
.u
.tcp
.port
= htons(port
);
49 if (nf_ct_expect_related(exp
) == 0)
56 ip
= ntohl(exp
->master
->tuplehash
[IP_CT_DIR_REPLY
].tuple
.dst
.u3
.ip
);
57 sprintf(buffer
, "%u %u", ip
, port
);
58 pr_debug("nf_nat_irc: inserting '%s' == %u.%u.%u.%u, port %u\n",
59 buffer
, NIPQUAD(ip
), port
);
61 ret
= nf_nat_mangle_tcp_packet(skb
, exp
->master
, ctinfo
,
62 matchoff
, matchlen
, buffer
,
65 nf_ct_unexpect_related(exp
);
69 static void __exit
nf_nat_irc_fini(void)
71 rcu_assign_pointer(nf_nat_irc_hook
, NULL
);
75 static int __init
nf_nat_irc_init(void)
77 BUG_ON(nf_nat_irc_hook
!= NULL
);
78 rcu_assign_pointer(nf_nat_irc_hook
, help
);
82 /* Prior to 2.6.11, we had a ports param. No longer, but don't break users. */
83 static int warn_set(const char *val
, struct kernel_param
*kp
)
85 printk(KERN_INFO KBUILD_MODNAME
86 ": kernel >= 2.6.10 only uses 'ports' for conntrack modules\n");
89 module_param_call(ports
, warn_set
, NULL
, NULL
, 0);
91 module_init(nf_nat_irc_init
);
92 module_exit(nf_nat_irc_fini
);