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/* L3/L4 protocol support for nf_conntrack. */
/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.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/types.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/vmalloc.h>
#include <linux/stddef.h>
#include <linux/err.h>
#include <linux/percpu.h>
#include <linux/moduleparam.h>
#include <linux/notifier.h>
#include <linux/kernel.h>
#include <linux/netdevice.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_l3proto.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_core.h>
struct nf_conntrack_l4proto **nf_ct_protos[PF_MAX] __read_mostly;
struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX] __read_mostly;
struct nf_conntrack_l4proto *
__nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
{
if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL))
return &nf_conntrack_l4proto_generic;
return nf_ct_protos[l3proto][l4proto];
}
/* this is guaranteed to always return a valid protocol helper, since
* it falls back to generic_protocol */
struct nf_conntrack_l4proto *
nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto)
{
struct nf_conntrack_l4proto *p;
preempt_disable();
p = __nf_ct_l4proto_find(l3proto, l4proto);
if (!try_module_get(p->me))
p = &nf_conntrack_l4proto_generic;
preempt_enable();
return p;
}
void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
{
module_put(p->me);
}
struct nf_conntrack_l3proto *
nf_ct_l3proto_find_get(u_int16_t l3proto)
{
struct nf_conntrack_l3proto *p;
preempt_disable();
p = __nf_ct_l3proto_find(l3proto);
if (!try_module_get(p->me))
p = &nf_conntrack_l3proto_generic;
preempt_enable();
return p;
}
void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
{
module_put(p->me);
}
int
nf_ct_l3proto_try_module_get(unsigned short l3proto)
{
int ret;
struct nf_conntrack_l3proto *p;
retry: p = nf_ct_l3proto_find_get(l3proto);
if (p == &nf_conntrack_l3proto_generic) {
ret = request_module("nf_conntrack-%d", l3proto);
if (!ret)
goto retry;
return -EPROTOTYPE;
}
return 0;
}
void nf_ct_l3proto_module_put(unsigned short l3proto)
{
struct nf_conntrack_l3proto *p;
preempt_disable();
p = __nf_ct_l3proto_find(l3proto);
preempt_enable();
module_put(p->me);
}
static int kill_l3proto(struct nf_conn *i, void *data)
{
return (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num ==
((struct nf_conntrack_l3proto *)data)->l3proto);
}
static int kill_l4proto(struct nf_conn *i, void *data)
{
struct nf_conntrack_l4proto *l4proto;
l4proto = (struct nf_conntrack_l4proto *)data;
return (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum ==
l4proto->l4proto) &&
(i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num ==
l4proto->l3proto);
}
int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
{
int ret = 0;
if (proto->l3proto >= AF_MAX) {
ret = -EBUSY;
goto out;
}
write_lock_bh(&nf_conntrack_lock);
if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_l3proto_generic) {
ret = -EBUSY;
goto out_unlock;
}
nf_ct_l3protos[proto->l3proto] = proto;
out_unlock:
write_unlock_bh(&nf_conntrack_lock);
out:
return ret;
}
int nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
{
int ret = 0;
if (proto->l3proto >= AF_MAX) {
ret = -EBUSY;
goto out;
}
write_lock_bh(&nf_conntrack_lock);
if (nf_ct_l3protos[proto->l3proto] != proto) {
write_unlock_bh(&nf_conntrack_lock);
ret = -EBUSY;
goto out;
}
nf_ct_l3protos[proto->l3proto] = &nf_conntrack_l3proto_generic;
write_unlock_bh(&nf_conntrack_lock);
/* Somebody could be still looking at the proto in bh. */
synchronize_net();
/* Remove all contrack entries for this protocol */
nf_ct_iterate_cleanup(kill_l3proto, proto);
out:
return ret;
}
/* FIXME: Allow NULL functions and sub in pointers to generic for
them. --RR */
int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
{
int ret = 0;
if (l4proto->l3proto >= PF_MAX) {
ret = -EBUSY;
goto out;
}
retry:
write_lock_bh(&nf_conntrack_lock);
if (nf_ct_protos[l4proto->l3proto]) {
if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto]
!= &nf_conntrack_l4proto_generic) {
ret = -EBUSY;
goto out_unlock;
}
} else {
/* l3proto may be loaded latter. */
struct nf_conntrack_l4proto **proto_array;
int i;
write_unlock_bh(&nf_conntrack_lock);
proto_array = (struct nf_conntrack_l4proto **)
kmalloc(MAX_NF_CT_PROTO *
sizeof(struct nf_conntrack_l4proto *),
GFP_KERNEL);
if (proto_array == NULL) {
ret = -ENOMEM;
goto out;
}
for (i = 0; i < MAX_NF_CT_PROTO; i++)
proto_array[i] = &nf_conntrack_l4proto_generic;
write_lock_bh(&nf_conntrack_lock);
if (nf_ct_protos[l4proto->l3proto]) {
/* bad timing, but no problem */
write_unlock_bh(&nf_conntrack_lock);
kfree(proto_array);
} else {
nf_ct_protos[l4proto->l3proto] = proto_array;
write_unlock_bh(&nf_conntrack_lock);
}
/*
* Just once because array is never freed until unloading
* nf_conntrack.ko
*/
goto retry;
}
nf_ct_protos[l4proto->l3proto][l4proto->l4proto] = l4proto;
out_unlock:
write_unlock_bh(&nf_conntrack_lock);
out:
return ret;
}
int nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
{
int ret = 0;
if (l4proto->l3proto >= PF_MAX) {
ret = -EBUSY;
goto out;
}
write_lock_bh(&nf_conntrack_lock);
if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto]
!= l4proto) {
write_unlock_bh(&nf_conntrack_lock);
ret = -EBUSY;
goto out;
}
nf_ct_protos[l4proto->l3proto][l4proto->l4proto]
= &nf_conntrack_l4proto_generic;
write_unlock_bh(&nf_conntrack_lock);
/* Somebody could be still looking at the proto in bh. */
synchronize_net();
/* Remove all contrack entries for this protocol */
nf_ct_iterate_cleanup(kill_l4proto, l4proto);
out:
return ret;
}
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