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>