2019-05-27 00:55:01 -06:00
|
|
|
// SPDX-License-Identifier: GPL-2.0-or-later
|
2006-12-02 23:08:26 -07:00
|
|
|
/* Amanda extension for TCP NAT alteration.
|
|
|
|
* (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca>
|
|
|
|
* based on a copy of HW's ip_nat_irc.c as well as other modules
|
2013-04-06 07:24:29 -06:00
|
|
|
* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
|
2006-12-02 23:08:26 -07:00
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/kernel.h>
|
|
|
|
#include <linux/module.h>
|
|
|
|
#include <linux/skbuff.h>
|
|
|
|
#include <linux/udp.h>
|
|
|
|
|
|
|
|
#include <net/netfilter/nf_conntrack_helper.h>
|
|
|
|
#include <net/netfilter/nf_conntrack_expect.h>
|
2012-06-07 04:11:50 -06:00
|
|
|
#include <net/netfilter/nf_nat_helper.h>
|
2006-12-02 23:08:26 -07:00
|
|
|
#include <linux/netfilter/nf_conntrack_amanda.h>
|
|
|
|
|
2019-04-17 08:46:16 -06:00
|
|
|
#define NAT_HELPER_NAME "amanda"
|
|
|
|
|
2006-12-02 23:08:26 -07:00
|
|
|
MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>");
|
|
|
|
MODULE_DESCRIPTION("Amanda NAT helper");
|
|
|
|
MODULE_LICENSE("GPL");
|
2019-04-17 08:46:16 -06:00
|
|
|
MODULE_ALIAS_NF_NAT_HELPER(NAT_HELPER_NAME);
|
|
|
|
|
|
|
|
static struct nf_conntrack_nat_helper nat_helper_amanda =
|
|
|
|
NF_CT_NAT_HELPER_INIT(NAT_HELPER_NAME);
|
2006-12-02 23:08:26 -07:00
|
|
|
|
2007-10-15 01:53:15 -06:00
|
|
|
static unsigned int help(struct sk_buff *skb,
|
2006-12-02 23:08:26 -07:00
|
|
|
enum ip_conntrack_info ctinfo,
|
2012-08-26 11:14:04 -06:00
|
|
|
unsigned int protoff,
|
2006-12-02 23:08:26 -07:00
|
|
|
unsigned int matchoff,
|
|
|
|
unsigned int matchlen,
|
|
|
|
struct nf_conntrack_expect *exp)
|
|
|
|
{
|
|
|
|
char buffer[sizeof("65535")];
|
|
|
|
u_int16_t port;
|
|
|
|
|
|
|
|
/* Connection comes from client. */
|
|
|
|
exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
|
|
|
|
exp->dir = IP_CT_DIR_ORIGINAL;
|
|
|
|
|
|
|
|
/* When you see the packet, we need to NAT it the same as the
|
|
|
|
* this one (ie. same IP: it will be TCP and master is UDP). */
|
|
|
|
exp->expectfn = nf_nat_follow_master;
|
|
|
|
|
|
|
|
/* Try to get same port: if not, try to change it. */
|
|
|
|
for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) {
|
2010-11-15 10:45:12 -07:00
|
|
|
int res;
|
2010-09-22 00:34:12 -06:00
|
|
|
|
2006-12-02 23:08:26 -07:00
|
|
|
exp->tuple.dst.u.tcp.port = htons(port);
|
2010-11-15 10:45:12 -07:00
|
|
|
res = nf_ct_expect_related(exp);
|
|
|
|
if (res == 0)
|
2010-09-22 00:34:12 -06:00
|
|
|
break;
|
2010-11-15 10:45:12 -07:00
|
|
|
else if (res != -EBUSY) {
|
2010-09-22 00:34:12 -06:00
|
|
|
port = 0;
|
2006-12-02 23:08:26 -07:00
|
|
|
break;
|
2010-09-22 00:34:12 -06:00
|
|
|
}
|
2006-12-02 23:08:26 -07:00
|
|
|
}
|
|
|
|
|
2013-02-10 10:56:56 -07:00
|
|
|
if (port == 0) {
|
|
|
|
nf_ct_helper_log(skb, exp->master, "all ports in use");
|
2006-12-02 23:08:26 -07:00
|
|
|
return NF_DROP;
|
2013-02-10 10:56:56 -07:00
|
|
|
}
|
2006-12-02 23:08:26 -07:00
|
|
|
|
|
|
|
sprintf(buffer, "%u", port);
|
2017-03-27 09:12:08 -06:00
|
|
|
if (!nf_nat_mangle_udp_packet(skb, exp->master, ctinfo,
|
|
|
|
protoff, matchoff, matchlen,
|
|
|
|
buffer, strlen(buffer))) {
|
2013-02-10 10:56:56 -07:00
|
|
|
nf_ct_helper_log(skb, exp->master, "cannot mangle packet");
|
2007-07-07 23:30:49 -06:00
|
|
|
nf_ct_unexpect_related(exp);
|
2017-03-27 09:12:08 -06:00
|
|
|
return NF_DROP;
|
2013-02-10 10:56:56 -07:00
|
|
|
}
|
2017-03-27 09:12:08 -06:00
|
|
|
return NF_ACCEPT;
|
2006-12-02 23:08:26 -07:00
|
|
|
}
|
|
|
|
|
|
|
|
static void __exit nf_nat_amanda_fini(void)
|
|
|
|
{
|
2019-04-17 08:46:16 -06:00
|
|
|
nf_nat_helper_unregister(&nat_helper_amanda);
|
2011-08-01 10:19:00 -06:00
|
|
|
RCU_INIT_POINTER(nf_nat_amanda_hook, NULL);
|
2006-12-02 23:08:26 -07:00
|
|
|
synchronize_rcu();
|
|
|
|
}
|
|
|
|
|
|
|
|
static int __init nf_nat_amanda_init(void)
|
|
|
|
{
|
2007-11-05 21:43:30 -07:00
|
|
|
BUG_ON(nf_nat_amanda_hook != NULL);
|
2019-04-17 08:46:16 -06:00
|
|
|
nf_nat_helper_register(&nat_helper_amanda);
|
2011-08-01 10:19:00 -06:00
|
|
|
RCU_INIT_POINTER(nf_nat_amanda_hook, help);
|
2006-12-02 23:08:26 -07:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
module_init(nf_nat_amanda_init);
|
|
|
|
module_exit(nf_nat_amanda_fini);
|