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nexedi
linux
Commits
64e535ee
Commit
64e535ee
authored
Apr 28, 2003
by
Stephen Hemminger
Committed by
David S. Miller
Apr 28, 2003
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Plain Diff
[NETFILTER]: Use Read Copy Update.
parent
7242b16a
Changes
2
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Showing
2 changed files
with
59 additions
and
22 deletions
+59
-22
include/linux/list.h
include/linux/list.h
+10
-0
net/core/netfilter.c
net/core/netfilter.c
+49
-22
No files found.
include/linux/list.h
View file @
64e535ee
...
...
@@ -335,6 +335,16 @@ static inline void list_splice_init(struct list_head *list,
prefetch(pos->member.next))
/**
* list_for_each_continue_rcu - iterate over an rcu-protected list
* continuing from existing point.
* @pos: the &struct list_head to use as a loop counter.
* @head: the head for your list.
*/
#define list_for_each_continue_rcu(pos, head) \
for ((pos) = (pos)->next, prefetch((pos)->next); (pos) != (head); \
(pos) = (pos)->next, ({ smp_read_barrier_depends(); 0;}), prefetch((pos)->next))
/*
* Double linked lists with a single pointer list head.
* Mostly useful for hash tables where the two pointer list head is
...
...
net/core/netfilter.c
View file @
64e535ee
...
...
@@ -19,7 +19,6 @@
#include <linux/interrupt.h>
#include <linux/if.h>
#include <linux/netdevice.h>
#include <linux/brlock.h>
#include <linux/inetdevice.h>
#include <net/sock.h>
#include <net/route.h>
...
...
@@ -40,12 +39,13 @@
#endif
/* Sockopts only registered and called from user context, so
BR_NETPROTO_LOCK
would be overkill. Also, [gs]etsockopt calls may
net locking
would be overkill. Also, [gs]etsockopt calls may
sleep. */
static
DECLARE_MUTEX
(
nf_sockopt_mutex
);
struct
list_head
nf_hooks
[
NPROTO
][
NF_MAX_HOOKS
];
static
LIST_HEAD
(
nf_sockopts
);
static
spinlock_t
nf_hook_lock
=
SPIN_LOCK_UNLOCKED
;
/*
* A queue handler may be registered for each protocol. Each is protected by
...
...
@@ -56,28 +56,31 @@ static struct nf_queue_handler_t {
nf_queue_outfn_t
outfn
;
void
*
data
;
}
queue_handler
[
NPROTO
];
static
rwlock_t
queue_handler_lock
=
RW_LOCK_UNLOCKED
;
int
nf_register_hook
(
struct
nf_hook_ops
*
reg
)
{
struct
list_head
*
i
;
br_write_lock_bh
(
BR_NETPROTO_LOCK
);
for
(
i
=
nf_hooks
[
reg
->
pf
][
reg
->
hooknum
].
next
;
i
!=
&
nf_hooks
[
reg
->
pf
][
reg
->
hooknum
];
i
=
i
->
next
)
{
spin_lock_bh
(
&
nf_hook_lock
);
list_for_each
(
i
,
&
nf_hooks
[
reg
->
pf
][
reg
->
hooknum
])
{
if
(
reg
->
priority
<
((
struct
nf_hook_ops
*
)
i
)
->
priority
)
break
;
}
list_add
(
&
reg
->
list
,
i
->
prev
);
br_write_unlock_bh
(
BR_NETPROTO_LOCK
);
list_add_rcu
(
&
reg
->
list
,
i
->
prev
);
spin_unlock_bh
(
&
nf_hook_lock
);
synchronize_net
();
return
0
;
}
void
nf_unregister_hook
(
struct
nf_hook_ops
*
reg
)
{
br_write_lock_bh
(
BR_NETPROTO_LOCK
);
list_del
(
&
reg
->
list
);
br_write_unlock_bh
(
BR_NETPROTO_LOCK
);
spin_lock_bh
(
&
nf_hook_lock
);
list_del_rcu
(
&
reg
->
list
);
spin_unlock_bh
(
&
nf_hook_lock
);
synchronize_net
();
}
/* Do exclusive ranges overlap? */
...
...
@@ -344,7 +347,11 @@ static unsigned int nf_iterate(struct list_head *head,
int
(
*
okfn
)(
struct
sk_buff
*
),
int
hook_thresh
)
{
for
(
*
i
=
(
*
i
)
->
next
;
*
i
!=
head
;
*
i
=
(
*
i
)
->
next
)
{
/*
* The caller must not block between calls to this
* function because of risk of continuing from deleted element.
*/
list_for_each_continue_rcu
(
*
i
,
head
)
{
struct
nf_hook_ops
*
elem
=
(
struct
nf_hook_ops
*
)
*
i
;
if
(
hook_thresh
>
elem
->
priority
)
...
...
@@ -383,7 +390,7 @@ int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data)
{
int
ret
;
br_write_lock_bh
(
BR_NETPROTO_LOCK
);
write_lock_bh
(
&
queue_handler_lock
);
if
(
queue_handler
[
pf
].
outfn
)
ret
=
-
EBUSY
;
else
{
...
...
@@ -391,7 +398,7 @@ int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data)
queue_handler
[
pf
].
data
=
data
;
ret
=
0
;
}
br_write_unlock_bh
(
BR_NETPROTO_LOCK
);
write_unlock_bh
(
&
queue_handler_lock
);
return
ret
;
}
...
...
@@ -399,10 +406,11 @@ int nf_register_queue_handler(int pf, nf_queue_outfn_t outfn, void *data)
/* The caller must flush their queue before this */
int
nf_unregister_queue_handler
(
int
pf
)
{
br_write_lock_bh
(
BR_NETPROTO_LOCK
);
write_lock_bh
(
&
queue_handler_lock
);
queue_handler
[
pf
].
outfn
=
NULL
;
queue_handler
[
pf
].
data
=
NULL
;
br_write_unlock_bh
(
BR_NETPROTO_LOCK
);
write_unlock_bh
(
&
queue_handler_lock
);
return
0
;
}
...
...
@@ -425,7 +433,9 @@ static int nf_queue(struct sk_buff *skb,
#endif
/* QUEUE == DROP if noone is waiting, to be safe. */
read_lock
(
&
queue_handler_lock
);
if
(
!
queue_handler
[
pf
].
outfn
)
{
read_unlock
(
&
queue_handler_lock
);
kfree_skb
(
skb
);
return
1
;
}
...
...
@@ -435,6 +445,7 @@ static int nf_queue(struct sk_buff *skb,
if
(
net_ratelimit
())
printk
(
KERN_ERR
"OOM queueing packet %p
\n
"
,
skb
);
read_unlock
(
&
queue_handler_lock
);
kfree_skb
(
skb
);
return
1
;
}
...
...
@@ -443,8 +454,11 @@ static int nf_queue(struct sk_buff *skb,
(
struct
nf_hook_ops
*
)
elem
,
pf
,
hook
,
indev
,
outdev
,
okfn
};
/* If it's going away, ignore hook. */
if
(
!
try_module_get
(
info
->
elem
->
owner
))
if
(
!
try_module_get
(
info
->
elem
->
owner
))
{
read_unlock
(
&
queue_handler_lock
);
kfree
(
info
);
return
0
;
}
/* Bump dev refs so they don't vanish while packet is out */
if
(
indev
)
dev_hold
(
indev
);
...
...
@@ -460,6 +474,8 @@ static int nf_queue(struct sk_buff *skb,
#endif
status
=
queue_handler
[
pf
].
outfn
(
skb
,
info
,
queue_handler
[
pf
].
data
);
read_unlock
(
&
queue_handler_lock
);
if
(
status
<
0
)
{
/* James M doesn't say fuck enough. */
if
(
indev
)
dev_put
(
indev
);
...
...
@@ -495,7 +511,7 @@ int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb,
}
/* We may already have this, but read-locks nest anyway */
br_read_lock_bh
(
BR_NETPROTO_LOCK
);
rcu_read_lock
(
);
#ifdef CONFIG_NETFILTER_DEBUG
if
(
skb
->
nf_debug
&
(
1
<<
hook
))
{
...
...
@@ -526,7 +542,7 @@ int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb,
break
;
}
br_read_unlock_bh
(
BR_NETPROTO_LOCK
);
rcu_read_unlock
(
);
return
ret
;
}
...
...
@@ -535,12 +551,23 @@ void nf_reinject(struct sk_buff *skb, struct nf_info *info,
{
struct
list_head
*
elem
=
&
info
->
elem
->
list
;
/* We don't have BR_NETPROTO_LOCK here */
br_read_lock_bh
(
BR_NETPROTO_LOCK
);
rcu_read_lock
();
/* Drop reference to owner of hook which queued us. */
module_put
(
info
->
elem
->
owner
);
list_for_each_rcu
(
i
,
&
nf_hooks
[
info
->
pf
][
info
->
hook
])
{
if
(
i
==
elem
)
break
;
}
if
(
elem
==
&
nf_hooks
[
info
->
pf
][
info
->
hook
])
{
/* The module which sent it to userspace is gone. */
NFDEBUG
(
"%s: module disappeared, dropping packet.
\n
"
,
__FUNCTION__
);
verdict
=
NF_DROP
;
}
/* Continue traversal iff userspace said ok... */
if
(
verdict
==
NF_REPEAT
)
{
elem
=
elem
->
prev
;
...
...
@@ -570,7 +597,7 @@ void nf_reinject(struct sk_buff *skb, struct nf_info *info,
kfree_skb
(
skb
);
break
;
}
br_read_unlock_bh
(
BR_NETPROTO_LOCK
);
rcu_read_unlock
(
);
/* Release those devices we held, or Alexey will kill me. */
if
(
info
->
indev
)
dev_put
(
info
->
indev
);
...
...
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