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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - net/netfilter/nf_nat_amanda.c
1 /* Amanda extension for TCP NAT alteration.
2 * (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca>
3 * based on a copy of HW's ip_nat_irc.c as well as other modules
4 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/skbuff.h>
15 #include <linux/udp.h>
17 #include <net/netfilter/nf_conntrack_helper.h>
18 #include <net/netfilter/nf_conntrack_expect.h>
19 #include <net/netfilter/nf_nat_helper.h>
20 #include <linux/netfilter/nf_conntrack_amanda.h>
22 MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
23 MODULE_DESCRIPTION("Amanda NAT helper");
24 MODULE_LICENSE("GPL");
25 MODULE_ALIAS("ip_nat_amanda");
27 static unsigned int help(struct sk_buff
*skb
,
28 enum ip_conntrack_info ctinfo
,
30 unsigned int matchoff
,
31 unsigned int matchlen
,
32 struct nf_conntrack_expect
*exp
)
34 char buffer
[sizeof("65535")];
37 /* Connection comes from client. */
38 exp
->saved_proto
.tcp
.port
= exp
->tuple
.dst
.u
.tcp
.port
;
39 exp
->dir
= IP_CT_DIR_ORIGINAL
;
41 /* When you see the packet, we need to NAT it the same as the
42 * this one (ie. same IP: it will be TCP and master is UDP). */
43 exp
->expectfn
= nf_nat_follow_master
;
45 /* Try to get same port: if not, try to change it. */
46 for (port
= ntohs(exp
->saved_proto
.tcp
.port
); port
!= 0; port
++) {
49 exp
->tuple
.dst
.u
.tcp
.port
= htons(port
);
50 res
= nf_ct_expect_related(exp
);
53 else if (res
!= -EBUSY
) {
60 nf_ct_helper_log(skb
, exp
->master
, "all ports in use");
64 sprintf(buffer
, "%u", port
);
65 if (!nf_nat_mangle_udp_packet(skb
, exp
->master
, ctinfo
,
66 protoff
, matchoff
, matchlen
,
67 buffer
, strlen(buffer
))) {
68 nf_ct_helper_log(skb
, exp
->master
, "cannot mangle packet");
69 nf_ct_unexpect_related(exp
);
75 static void __exit
nf_nat_amanda_fini(void)
77 RCU_INIT_POINTER(nf_nat_amanda_hook
, NULL
);
81 static int __init
nf_nat_amanda_init(void)
83 BUG_ON(nf_nat_amanda_hook
!= NULL
);
84 RCU_INIT_POINTER(nf_nat_amanda_hook
, help
);
88 module_init(nf_nat_amanda_init
);
89 module_exit(nf_nat_amanda_fini
);