Commit ecfab2c9 authored by Yasuyuki Kozakai's avatar Yasuyuki Kozakai Committed by David S. Miller

[NETFILTER]: nf_conntrack: introduce extension infrastructure

Old space allocator of conntrack had problems about extensibility.
- It required slab cache per combination of extensions.
- It expected what extensions would be assigned, but it was impossible
  to expect that completely, then we allocated bigger memory object than
  really required.
- It needed to search helper twice due to lock issue.

Now basic informations of a connection are stored in 'struct nf_conn'.
And a storage for extension (helper, NAT) is allocated by kmalloc.
Signed-off-by: default avatarYasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4ba88779
......@@ -131,6 +131,9 @@ struct nf_conn
/* Storage reserved for other modules: */
union nf_conntrack_proto proto;
/* Extensions */
struct nf_ct_ext *ext;
/* features dynamically at the end: helper, nat (both optional) */
char data[0];
};
......
#ifndef _NF_CONNTRACK_EXTEND_H
#define _NF_CONNTRACK_EXTEND_H
#include <net/netfilter/nf_conntrack.h>
enum nf_ct_ext_id
{
NF_CT_EXT_NUM,
};
/* Extensions: optional stuff which isn't permanently in struct. */
struct nf_ct_ext {
u8 offset[NF_CT_EXT_NUM];
u8 len;
u8 real_len;
char data[0];
};
static inline int nf_ct_ext_exist(const struct nf_conn *ct, u8 id)
{
return (ct->ext && ct->ext->offset[id]);
}
static inline void *__nf_ct_ext_find(const struct nf_conn *ct, u8 id)
{
if (!nf_ct_ext_exist(ct, id))
return NULL;
return (void *)ct->ext + ct->ext->offset[id];
}
#define nf_ct_ext_find(ext, id) \
((id##_TYPE *)__nf_ct_ext_find((ext), (id)))
/* Destroy all relationships */
extern void __nf_ct_ext_destroy(struct nf_conn *ct);
static inline void nf_ct_ext_destroy(struct nf_conn *ct)
{
if (ct->ext)
__nf_ct_ext_destroy(ct);
}
/* Free operation. If you want to free a object referred from private area,
* please implement __nf_ct_ext_free() and call it.
*/
static inline void nf_ct_ext_free(struct nf_conn *ct)
{
if (ct->ext)
kfree(ct->ext);
}
/* Add this type, returns pointer to data or NULL. */
void *
__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp);
#define nf_ct_ext_add(ct, id, gfp) \
((id##_TYPE *)__nf_ct_ext_add((ct), (id), (gfp)))
#define NF_CT_EXT_F_PREALLOC 0x0001
struct nf_ct_ext_type
{
/* Destroys relationships (can be NULL). */
void (*destroy)(struct nf_conn *ct);
/* Called when realloacted (can be NULL).
Contents has already been moved. */
void (*move)(struct nf_conn *ct, void *old);
enum nf_ct_ext_id id;
unsigned int flags;
/* Length and min alignment. */
u8 len;
u8 align;
/* initial size of nf_ct_ext. */
u8 alloc_size;
};
int nf_ct_extend_register(struct nf_ct_ext_type *type);
void nf_ct_extend_unregister(struct nf_ct_ext_type *type);
#endif /* _NF_CONNTRACK_EXTEND_H */
netfilter-objs := core.o nf_log.o nf_queue.o nf_sockopt.o
nf_conntrack-y := nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_expect.o nf_conntrack_helper.o nf_conntrack_proto.o nf_conntrack_l3proto_generic.o nf_conntrack_proto_generic.o nf_conntrack_proto_tcp.o nf_conntrack_proto_udp.o
nf_conntrack-y := nf_conntrack_core.o nf_conntrack_standalone.o nf_conntrack_expect.o nf_conntrack_helper.o nf_conntrack_proto.o nf_conntrack_l3proto_generic.o nf_conntrack_proto_generic.o nf_conntrack_proto_tcp.o nf_conntrack_proto_udp.o nf_conntrack_extend.o
nf_conntrack-$(CONFIG_NF_CONNTRACK_EVENTS) += nf_conntrack_ecache.o
obj-$(CONFIG_NETFILTER) = netfilter.o
......
......@@ -36,6 +36,7 @@
#include <net/netfilter/nf_conntrack_expect.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_extend.h>
#define NF_CONNTRACK_VERSION "0.5.0"
......@@ -317,6 +318,8 @@ destroy_conntrack(struct nf_conntrack *nfct)
if (l4proto && l4proto->destroy)
l4proto->destroy(ct);
nf_ct_ext_destroy(ct);
destroyed = rcu_dereference(nf_conntrack_destroyed);
if (destroyed)
destroyed(ct);
......@@ -650,6 +653,7 @@ void nf_conntrack_free(struct nf_conn *conntrack)
{
u_int32_t features = conntrack->features;
NF_CT_ASSERT(features >= NF_CT_F_BASIC && features < NF_CT_F_NUM);
nf_ct_ext_free(conntrack);
DEBUGP("nf_conntrack_free: features = 0x%x, conntrack=%p\n", features,
conntrack);
kmem_cache_free(nf_ct_cache[features].cachep, conntrack);
......
/* Structure dynamic extension infrastructure
* Copyright (C) 2004 Rusty Russell IBM Corporation
* Copyright (C) 2007 Netfilter Core Team <coreteam@netfilter.org>
* Copyright (C) 2007 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
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/rcupdate.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <net/netfilter/nf_conntrack_extend.h>
static struct nf_ct_ext_type *nf_ct_ext_types[NF_CT_EXT_NUM];
static DEFINE_MUTEX(nf_ct_ext_type_mutex);
/* Horrible trick to figure out smallest amount worth kmallocing. */
#define CACHE(x) (x) + 0 *
enum {
NF_CT_EXT_MIN_SIZE =
#include <linux/kmalloc_sizes.h>
1 };
#undef CACHE
void __nf_ct_ext_destroy(struct nf_conn *ct)
{
unsigned int i;
struct nf_ct_ext_type *t;
for (i = 0; i < NF_CT_EXT_NUM; i++) {
if (!nf_ct_ext_exist(ct, i))
continue;
rcu_read_lock();
t = rcu_dereference(nf_ct_ext_types[i]);
/* Here the nf_ct_ext_type might have been unregisterd.
* I.e., it has responsible to cleanup private
* area in all conntracks when it is unregisterd.
*/
if (t && t->destroy)
t->destroy(ct);
rcu_read_unlock();
}
}
EXPORT_SYMBOL(__nf_ct_ext_destroy);
static void *
nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp)
{
unsigned int off, len, real_len;
struct nf_ct_ext_type *t;
rcu_read_lock();
t = rcu_dereference(nf_ct_ext_types[id]);
BUG_ON(t == NULL);
off = ALIGN(sizeof(struct nf_ct_ext), t->align);
len = off + t->len;
real_len = t->alloc_size;
rcu_read_unlock();
*ext = kzalloc(real_len, gfp);
if (!*ext)
return NULL;
(*ext)->offset[id] = off;
(*ext)->len = len;
(*ext)->real_len = real_len;
return (void *)(*ext) + off;
}
void *__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
{
struct nf_ct_ext *new;
int i, newlen, newoff;
struct nf_ct_ext_type *t;
if (!ct->ext)
return nf_ct_ext_create(&ct->ext, id, gfp);
if (nf_ct_ext_exist(ct, id))
return NULL;
rcu_read_lock();
t = rcu_dereference(nf_ct_ext_types[id]);
BUG_ON(t == NULL);
newoff = ALIGN(ct->ext->len, t->align);
newlen = newoff + t->len;
rcu_read_unlock();
if (newlen >= ct->ext->real_len) {
new = kmalloc(newlen, gfp);
if (!new)
return NULL;
memcpy(new, ct->ext, ct->ext->len);
for (i = 0; i < NF_CT_EXT_NUM; i++) {
if (!nf_ct_ext_exist(ct, i))
continue;
rcu_read_lock();
t = rcu_dereference(nf_ct_ext_types[i]);
if (t && t->move)
t->move(ct, ct->ext + ct->ext->offset[id]);
rcu_read_unlock();
}
kfree(ct->ext);
new->real_len = newlen;
ct->ext = new;
}
ct->ext->offset[id] = newoff;
ct->ext->len = newlen;
memset((void *)ct->ext + newoff, 0, newlen - newoff);
return (void *)ct->ext + newoff;
}
EXPORT_SYMBOL(__nf_ct_ext_add);
static void update_alloc_size(struct nf_ct_ext_type *type)
{
int i, j;
struct nf_ct_ext_type *t1, *t2;
enum nf_ct_ext_id min = 0, max = NF_CT_EXT_NUM - 1;
/* unnecessary to update all types */
if ((type->flags & NF_CT_EXT_F_PREALLOC) == 0) {
min = type->id;
max = type->id;
}
/* This assumes that extended areas in conntrack for the types
whose NF_CT_EXT_F_PREALLOC bit set are allocated in order */
for (i = min; i <= max; i++) {
t1 = nf_ct_ext_types[i];
if (!t1)
continue;
t1->alloc_size = sizeof(struct nf_ct_ext)
+ ALIGN(sizeof(struct nf_ct_ext), t1->align)
+ t1->len;
for (j = 0; j < NF_CT_EXT_NUM; j++) {
t2 = nf_ct_ext_types[j];
if (t2 == NULL || t2 == t1 ||
(t2->flags & NF_CT_EXT_F_PREALLOC) == 0)
continue;
t1->alloc_size = ALIGN(t1->alloc_size, t2->align)
+ t2->len;
}
if (t1->alloc_size < NF_CT_EXT_MIN_SIZE)
t1->alloc_size = NF_CT_EXT_MIN_SIZE;
}
}
/* This MUST be called in process context. */
int nf_ct_extend_register(struct nf_ct_ext_type *type)
{
int ret = 0;
mutex_lock(&nf_ct_ext_type_mutex);
if (nf_ct_ext_types[type->id]) {
ret = -EBUSY;
goto out;
}
/* This ensures that nf_ct_ext_create() can allocate enough area
before updating alloc_size */
type->alloc_size = ALIGN(sizeof(struct nf_ct_ext), type->align)
+ type->len;
rcu_assign_pointer(nf_ct_ext_types[type->id], type);
update_alloc_size(type);
out:
mutex_unlock(&nf_ct_ext_type_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(nf_ct_extend_register);
/* This MUST be called in process context. */
void nf_ct_extend_unregister(struct nf_ct_ext_type *type)
{
mutex_lock(&nf_ct_ext_type_mutex);
rcu_assign_pointer(nf_ct_ext_types[type->id], NULL);
update_alloc_size(type);
mutex_unlock(&nf_ct_ext_type_mutex);
synchronize_rcu();
}
EXPORT_SYMBOL_GPL(nf_ct_extend_unregister);
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