![Patrick McHardy](/assets/img/avatar_default.png)
As noticed by Paul McKenney, the rcu_dereference calls in the init path of NAT modules are unneeded, remove them. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
166 lines
4.5 KiB
C
166 lines
4.5 KiB
C
/* FTP extension for TCP NAT alteration. */
|
|
|
|
/* (C) 1999-2001 Paul `Rusty' Russell
|
|
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <linux/ip.h>
|
|
#include <linux/tcp.h>
|
|
#include <linux/netfilter_ipv4.h>
|
|
#include <net/netfilter/nf_nat.h>
|
|
#include <net/netfilter/nf_nat_helper.h>
|
|
#include <net/netfilter/nf_nat_rule.h>
|
|
#include <net/netfilter/nf_conntrack_helper.h>
|
|
#include <net/netfilter/nf_conntrack_expect.h>
|
|
#include <linux/netfilter/nf_conntrack_ftp.h>
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>");
|
|
MODULE_DESCRIPTION("ftp NAT helper");
|
|
MODULE_ALIAS("ip_nat_ftp");
|
|
|
|
/* FIXME: Time out? --RR */
|
|
|
|
static int
|
|
mangle_rfc959_packet(struct sk_buff *skb,
|
|
__be32 newip,
|
|
u_int16_t port,
|
|
unsigned int matchoff,
|
|
unsigned int matchlen,
|
|
struct nf_conn *ct,
|
|
enum ip_conntrack_info ctinfo)
|
|
{
|
|
char buffer[sizeof("nnn,nnn,nnn,nnn,nnn,nnn")];
|
|
|
|
sprintf(buffer, "%u,%u,%u,%u,%u,%u",
|
|
NIPQUAD(newip), port>>8, port&0xFF);
|
|
|
|
pr_debug("calling nf_nat_mangle_tcp_packet\n");
|
|
|
|
return nf_nat_mangle_tcp_packet(skb, ct, ctinfo, matchoff,
|
|
matchlen, buffer, strlen(buffer));
|
|
}
|
|
|
|
/* |1|132.235.1.2|6275| */
|
|
static int
|
|
mangle_eprt_packet(struct sk_buff *skb,
|
|
__be32 newip,
|
|
u_int16_t port,
|
|
unsigned int matchoff,
|
|
unsigned int matchlen,
|
|
struct nf_conn *ct,
|
|
enum ip_conntrack_info ctinfo)
|
|
{
|
|
char buffer[sizeof("|1|255.255.255.255|65535|")];
|
|
|
|
sprintf(buffer, "|1|%u.%u.%u.%u|%u|", NIPQUAD(newip), port);
|
|
|
|
pr_debug("calling nf_nat_mangle_tcp_packet\n");
|
|
|
|
return nf_nat_mangle_tcp_packet(skb, ct, ctinfo, matchoff,
|
|
matchlen, buffer, strlen(buffer));
|
|
}
|
|
|
|
/* |1|132.235.1.2|6275| */
|
|
static int
|
|
mangle_epsv_packet(struct sk_buff *skb,
|
|
__be32 newip,
|
|
u_int16_t port,
|
|
unsigned int matchoff,
|
|
unsigned int matchlen,
|
|
struct nf_conn *ct,
|
|
enum ip_conntrack_info ctinfo)
|
|
{
|
|
char buffer[sizeof("|||65535|")];
|
|
|
|
sprintf(buffer, "|||%u|", port);
|
|
|
|
pr_debug("calling nf_nat_mangle_tcp_packet\n");
|
|
|
|
return nf_nat_mangle_tcp_packet(skb, ct, ctinfo, matchoff,
|
|
matchlen, buffer, strlen(buffer));
|
|
}
|
|
|
|
static int (*mangle[])(struct sk_buff *, __be32, u_int16_t,
|
|
unsigned int, unsigned int, struct nf_conn *,
|
|
enum ip_conntrack_info)
|
|
= {
|
|
[NF_CT_FTP_PORT] = mangle_rfc959_packet,
|
|
[NF_CT_FTP_PASV] = mangle_rfc959_packet,
|
|
[NF_CT_FTP_EPRT] = mangle_eprt_packet,
|
|
[NF_CT_FTP_EPSV] = mangle_epsv_packet
|
|
};
|
|
|
|
/* So, this packet has hit the connection tracking matching code.
|
|
Mangle it, and change the expectation to match the new version. */
|
|
static unsigned int nf_nat_ftp(struct sk_buff *skb,
|
|
enum ip_conntrack_info ctinfo,
|
|
enum nf_ct_ftp_type type,
|
|
unsigned int matchoff,
|
|
unsigned int matchlen,
|
|
struct nf_conntrack_expect *exp)
|
|
{
|
|
__be32 newip;
|
|
u_int16_t port;
|
|
int dir = CTINFO2DIR(ctinfo);
|
|
struct nf_conn *ct = exp->master;
|
|
|
|
pr_debug("FTP_NAT: type %i, off %u len %u\n", type, matchoff, matchlen);
|
|
|
|
/* Connection will come from wherever this packet goes, hence !dir */
|
|
newip = ct->tuplehash[!dir].tuple.dst.u3.ip;
|
|
exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
|
|
exp->dir = !dir;
|
|
|
|
/* When you see the packet, we need to NAT it the same as the
|
|
* this one. */
|
|
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++) {
|
|
exp->tuple.dst.u.tcp.port = htons(port);
|
|
if (nf_ct_expect_related(exp) == 0)
|
|
break;
|
|
}
|
|
|
|
if (port == 0)
|
|
return NF_DROP;
|
|
|
|
if (!mangle[type](skb, newip, port, matchoff, matchlen, ct, ctinfo)) {
|
|
nf_ct_unexpect_related(exp);
|
|
return NF_DROP;
|
|
}
|
|
return NF_ACCEPT;
|
|
}
|
|
|
|
static void __exit nf_nat_ftp_fini(void)
|
|
{
|
|
rcu_assign_pointer(nf_nat_ftp_hook, NULL);
|
|
synchronize_rcu();
|
|
}
|
|
|
|
static int __init nf_nat_ftp_init(void)
|
|
{
|
|
BUG_ON(nf_nat_ftp_hook != NULL);
|
|
rcu_assign_pointer(nf_nat_ftp_hook, nf_nat_ftp);
|
|
return 0;
|
|
}
|
|
|
|
/* Prior to 2.6.11, we had a ports param. No longer, but don't break users. */
|
|
static int warn_set(const char *val, struct kernel_param *kp)
|
|
{
|
|
printk(KERN_INFO KBUILD_MODNAME
|
|
": kernel >= 2.6.10 only uses 'ports' for conntrack modules\n");
|
|
return 0;
|
|
}
|
|
module_param_call(ports, warn_set, NULL, NULL, 0);
|
|
|
|
module_init(nf_nat_ftp_init);
|
|
module_exit(nf_nat_ftp_fini);
|