The problem is that while we work w/o the inet_frags.lock even
read-locked the secret rebuild timer may occur (on another CPU, since
BHs are still disabled in the inet_frag_find) and change the rnd seed
for ipv4/6 fragments.

It was caused by my patch fd9e6354
([INET]: Omit double hash calculations in xxx_frag_intern) late 
in the 2.6.24 kernel, so this should probably be queued to -stable.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Based upon a lockdep trace from Dave Jones.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On Fri, 2008-03-28 at 03:24 -0700, Andrew Morton wrote:
> they should all be renamed.

Done for include/net and net
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On namespace start we mainly prepare the ctl variables.

When the namespace is stopped we have to kill all the fragments that
point to this namespace.  The inet_frags_exit_net() handles it.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The inet_frags.lru_list is used for evicting only, so we have
to make it per-namespace, to evict only those fragments, who's
namespace exceeded its high threshold, but not the whole hash.
Besides, this helps to avoid long loops  in evictor.

The spinlock is not per-namespace because it protects the
hash table as well, which is global.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since we have one hashtable to lookup the fragment, having
different secret_interval-s for hash rebuild doesn't make
sense, so move this one to inet_frags.

The inet_frags_ctl becomes empty after this, so remove it.
The appropriate ctl table is kept read-only in namespaces.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is the same as with the timeout variable.

Currently, after exceeding the high threshold _all_
the fragments are evicted, but it will be fixed in
later patch.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move it to the netns_frags, adjust the usage and
make the appropriate ctl table writable.

Now fragment, that live in different namespaces can
live for different times.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is also simple, but introduces more changes, since
then mem counter is altered in more places.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is simple - just move the variable from struct inet_frags
to struct netns_frags and adjust the usage appropriately.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since fragment management code is consolidated, we cannot have the
pointer from inet_frag_queue to struct net, since we must know what
king of fragment this is.

So, I introduce the netns_frags structure. This one is currently
empty, but will be eventually filled with per-namespace
attributes. Each inet_frag_queue is tagged with this one.

The conntrack_reasm is not "netns-izated", so it has one static
netns_frags instance to keep working in init namespace.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Many-many code in the kernel initialized the timer->function
and  timer->data together with calling init_timer(timer). There
is already a helper for this. Use it for networking code.

The patch is HUGE, but makes the code 130 lines shorter
(98 insertions(+), 228 deletions(-)).
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Acked-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since we now allocate the queues in inet_fragment.c, we
can safely free it in the same place. The ->destructor
callback thus becomes optional for inet_frags.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since this callback is used to check for conflicts in
hashtable when inserting a newly created frag queue, we can
do the same by checking for matching the queue with the 
argument, used to create one.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Here we need another callback ->match to check whether the
entry found in hash matches the key passed. The key used 
is the same as the creation argument for inet_frag_create.

Yet again, this ->match is the same for netfilter and ipv6.
Running a frew steps forward - this callback will later
replace the ->equal one.

Since the inet_frag_find() uses the already consolidated
inet_frag_create() remove the xxx_frag_create from protocol
codes.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This one uses the xxx_frag_intern() and xxx_frag_alloc()
routines, which are already consolidated, so remove them
from protocol code (as promised).

The ->constructor callback is used to init the rest of
the frag queue and it is the same for netfilter and ipv6.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Just perform the kzalloc() allocation and setup common
fields in the inet_frag_queue(). Then return the result
to the caller to initialize the rest.

The inet_frag_alloc() may return NULL, so check the 
return value before doing the container_of(). This looks 
ugly, but the xxx_frag_alloc() will be removed soon.

The xxx_expire() timer callbacks are patches, 
because the argument is now the inet_frag_queue, not 
the protocol specific queue.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This routine checks for the existence of a given entry
in the hash table and inserts the new one if needed.

The ->equal callback is used to compare two frag_queue-s
together, but this one is temporary and will be removed
later. The netfilter code and the ipv6 one use the same
routine to compare frags.

The inet_frag_intern() always returns non-NULL pointer,
so convert the inet_frag_queue into protocol specific
one (with the container_of) without any checks.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The evictors collect some statistics for ipv4 and ipv6,
so make it return the number of evicted queues and account
them all at once in the caller.

The XXX_ADD_STATS_BH() macros are just for this case,
but maybe there are places in code, that can make use of
them as well.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To make in possible we need to know the exact frag queue
size for inet_frags->mem management and two callbacks:

 * to destoy the skb (optional, used in conntracks only)
 * to free the queue itself (mandatory, but later I plan to
   move the allocation and the destruction of frag_queues
   into the common place, so this callback will most likely
   be optional too).
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This code works with the generic data types as well, so
move this into inet_fragment.c

This move makes it possible to hide the secret_timer
management and the secret_rebuild routine completely in
the inet_fragment.c

Introduce the ->hashfn() callback in inet_frags() to get
the hashfun for a given inet_frag_queue() object.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since now all the xxx_frag_kill functions now work
with the generic inet_frag_queue data type, this can
be moved into a common place.

The xxx_unlink() code is moved as well.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are some objects that are common in all the places
which are used to keep track of frag queues, they are:

 * hash table
 * LRU list
 * rw lock
 * rnd number for hash function
 * the number of queues
 * the amount of memory occupied by queues
 * secret timer

Move all this stuff into one structure (struct inet_frags)
to make it possible use them uniformly in the future. Like
with the previous patch this mostly consists of hunks like

-    write_lock(&ipfrag_lock);
+    write_lock(&ip4_frags.lock);

To address the issue with exporting the number of queues and
the amount of memory occupied by queues outside the .c file
they are declared in, I introduce a couple of helpers.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>