netfilter: conntrack: fix extension size table

The size table is incorrect due to copypaste error,
this reserves more size than needed.

TSTAMP reserved 32 instead of 16 bytes.
TIMEOUT reserved 16 instead of 8 bytes.

Fixes: 5f31edc0676b ("netfilter: conntrack: move extension sizes into core")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: extensions: introduce extension genid count

Multiple netfilter extensions store pointers to external data
in their extension area struct.

Examples:
1. Timeout policies
2. Connection tracking helpers.

No references are taken for these.

When a helper or timeout policy is removed, the conntrack table gets
traversed and affected extensions are cleared.

Conntrack entries not yet in the hashtable are referenced via a special
list, the unconfirmed list.

On removal of a policy or connection tracking helper, the unconfirmed
list gets traversed an all entries are marked as dying, this prevents
them from getting committed to the table at insertion time: core checks
for dying bit, if set, the conntrack entry gets destroyed at confirm
time.

The disadvantage is that each new conntrack has to be added to the percpu
unconfirmed list, and each insertion needs to remove it from this list.
The list is only ever needed when a policy or helper is removed -- a rare
occurrence.

Add a generation ID count: Instead of adding to the list and then
traversing that list on policy/helper removal, increment a counter
that is stored in the extension area.

For unconfirmed conntracks, the extension has the genid valid at ct
allocation time.

Removal of a helper/policy etc. increments the counter.
At confirmation time, validate that ext->genid == global_id.

If the stored number is not the same, do not allow the conntrack
insertion, just like as if a confirmed-list traversal would have flagged
the entry as dying.

After insertion, the genid is no longer relevant (conntrack entries
are now reachable via the conntrack table iterators and is set to 0.

This allows removal of the percpu unconfirmed list.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove extension register api

These no longer register/unregister a meaningful structure so remove it.

Cc: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: handle ->destroy hook via nat_ops instead

The nat module already exposes a few functions to the conntrack core.
Move the nat extension destroy hook to it.

After this, no conntrack extension needs a destroy hook.
'struct nf_ct_ext_type' and the register/unregister api can be removed
in a followup patch.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: move extension sizes into core

No need to specify this in the registration modules, we already
collect all sizes for build-time checks on the maximum combined size.

After this change, all extensions except nat have no meaningful content
in their nf_ct_ext_type struct definition.

Next patch handles nat, this will then allow to remove the dynamic
register api completely.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: make all extensions 8-byte alignned

All extensions except one need 8 byte alignment, so just make that the
default.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove two export symbols

Not used anywhere, remove them.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: free extension area immediately

Instead of waiting for rcu grace period just free it directly.

This is safe because conntrack lookup doesn't consider extensions.

Other accesses happen while ct->ext can't be free'd, either because
a ct refcount was taken or because the conntrack hash bucket lock or
the dying list spinlock have been taken.

This allows to remove __krealloc in a followup patch, netfilter was the
only user.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

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

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

netfilter: conntrack: include kmemleak.h for kmemleak_not_leak()

After merging the netfilter tree, today's linux-next build (powerpc
ppc64_defconfig) failed like this:

net/netfilter/nf_conntrack_extend.c: In function 'nf_ct_ext_add':
net/netfilter/nf_conntrack_extend.c:74:2: error: implicit declaration of function 'kmemleak_not_leak' [-Werror=implicit-function-declaration]
kmemleak_not_leak(old);
^~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors

Fixes: 114aa35d06d4 ("netfilter: conntrack: silent a memory leak warning")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: silent a memory leak warning

The following memory leak is false postive:

unreferenced object 0xffff8f37f156fb38 (size 128):
comm "softirq", pid 0, jiffies 4294899665 (age 11.292s)
hex dump (first 32 bytes):
6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
00 00 00 00 30 00 20 00 48 6b 6b 6b 6b 6b 6b 6b ....0. .Hkkkkkkk
backtrace:
[<000000004fda266a>] __kmalloc_track_caller+0x10d/0x141
[<000000007b0a7e3c>] __krealloc+0x45/0x62
[<00000000d08e0bfb>] nf_ct_ext_add+0xdc/0x133
[<0000000099b47fd8>] init_conntrack+0x1b1/0x392
[<0000000086dc36ec>] nf_conntrack_in+0x1ee/0x34b
[<00000000940592de>] nf_hook_slow+0x36/0x95
[<00000000d1bd4da7>] nf_hook.constprop.43+0x1c3/0x1dd
[<00000000c3673266>] __ip_local_out+0xae/0xb4
[<000000003e4192a6>] ip_local_out+0x17/0x33
[<00000000b64356de>] igmp_ifc_timer_expire+0x23e/0x26f
[<000000006a8f3032>] call_timer_fn+0x14c/0x2a5
[<00000000650c1725>] __run_timers.part.34+0x150/0x182
[<0000000090e6946e>] run_timer_softirq+0x2a/0x4c
[<000000004d1e7293>] __do_softirq+0x1d1/0x3c2
[<000000004643557d>] irq_exit+0x53/0xa2
[<0000000029ddee8f>] smp_apic_timer_interrupt+0x22a/0x235

because __krealloc() is not supposed to release the old
memory and it is released later via kfree_rcu(). Since this is
the only external user of __krealloc(), just mark it as not leak
here.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net: Replace NF_CT_ASSERT() with WARN_ON().

This patch removes NF_CT_ASSERT() and instead uses WARN_ON().

Signed-off-by: Varsha Rao <rvarsha016@gmail.com>

netfilter: nf_ct_ext: invoke destroy even when ext is not attached

For NF_NAT_MANIP_SRC, we will insert the ct to the nat_bysource_table,
then remove it from the nat_bysource_table via nat_extend->destroy.

But now, the nat extension is attached on demand, so if the nat extension
is not attached, we will not be notified when the ct is destroyed, i.e.
we may fail to remove ct from the nat_bysource_table.

So just keep it simple, even if the extension is not attached, we will
still invoke the related ext->destroy. And this will also preserve the
flexibility for the future extension.

Fixes: 9a08ecfe74d7 ("netfilter: don't attach a nat extension by default")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: handle initial extension alloc via krealloc

krealloc(NULL, ..) is same as kmalloc(), so we can avoid special-casing
the initial allocation after the prealloc removal (we had to use
->alloc_len as the initial allocation size).

This also means we do not zero the preallocated memory anymore; only
offsets[]. Existing code makes sure the new (used) extension space gets
zeroed out.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: mark extension structs as const

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: conntrack: remove prealloc support

It was used by the nat extension, but since commit
7c9664351980 ("netfilter: move nat hlist_head to nf_conn") its only needed
for connections that use MASQUERADE target or a nat helper.

Also it seems a lot easier to preallocate a fixed size instead.

With default settings, conntrack first adds ecache extension (sysctl
defaults to 1), so we get 40(ct extension header) + 24 (ecache) == 64 byte
on x86_64 for initial allocation.

Followup patches can constify the extension structs and avoid
the initial zeroing of the entire extension area.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: remove last traces of variable-sized extensions

get rid of the (now unused) nf_ct_ext_add_length define and also
rename the function to plain nf_ct_ext_add().

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_ct_ext: fix possible panic after nf_ct_extend_unregister

If one cpu is doing nf_ct_extend_unregister while another cpu is doing
__nf_ct_ext_add_length, then we may hit BUG_ON(t == NULL). Moreover,
there's no synchronize_rcu invocation after set nf_ct_ext_types[id] to
NULL, so it's possible that we may access invalid pointer.

But actually, most of the ct extends are built-in, so the problem listed
above will not happen. However, there are two exceptions: NF_CT_EXT_NAT
and NF_CT_EXT_SYNPROXY.

For _EXT_NAT, the panic will not happen, since adding the nat extend and
unregistering the nat extend are located in the same file(nf_nat_core.c),
this means that after the nat module is removed, we cannot add the nat
extend too.

For _EXT_SYNPROXY, synproxy extend may be added by init_conntrack, while
synproxy extend unregister will be done by synproxy_core_exit. So after
nf_synproxy_core.ko is removed, we may still try to add the synproxy
extend, then kernel panic may happen.

I know it's very hard to reproduce this issue, but I can play a tricky
game to make it happen very easily :)

Step 1. Enable SYNPROXY for tcp dport 1234 at FORWARD hook:
# iptables -I FORWARD -p tcp --dport 1234 -j SYNPROXY
Step 2. Queue the syn packet to the userspace at raw table OUTPUT hook.
Also note, in the userspace we only add a 20s' delay, then
reinject the syn packet to the kernel:
# iptables -t raw -I OUTPUT -p tcp --syn -j NFQUEUE --queue-num 1
Step 3. Using "nc 2.2.2.2 1234" to connect the server.
Step 4. Now remove the nf_synproxy_core.ko quickly:
# iptables -F FORWARD
# rmmod ipt_SYNPROXY
# rmmod nf_synproxy_core
Step 5. After 20s' delay, the syn packet is reinjected to the kernel.

Now you will see the panic like this:
kernel BUG at net/netfilter/nf_conntrack_extend.c:91!
Call Trace:
? __nf_ct_ext_add_length+0x53/0x3c0 [nf_conntrack]
init_conntrack+0x12b/0x600 [nf_conntrack]
nf_conntrack_in+0x4cc/0x580 [nf_conntrack]
ipv4_conntrack_local+0x48/0x50 [nf_conntrack_ipv4]
nf_reinject+0x104/0x270
nfqnl_recv_verdict+0x3e1/0x5f9 [nfnetlink_queue]
? nfqnl_recv_verdict+0x5/0x5f9 [nfnetlink_queue]
? nla_parse+0xa0/0x100
nfnetlink_rcv_msg+0x175/0x6a9 [nfnetlink]
[...]

One possible solution is to make NF_CT_EXT_SYNPROXY extend built-in, i.e.
introduce nf_conntrack_synproxy.c and only do ct extend register and
unregister in it, similar to nf_conntrack_timeout.c.

But having such a obscure restriction of nf_ct_extend_unregister is not a
good idea, so we should invoke synchronize_rcu after set nf_ct_ext_types
to NULL, and check the NULL pointer when do __nf_ct_ext_add_length. Then
it will be easier if we add new ct extend in the future.

Last, we use kfree_rcu to free nf_ct_ext, so rcu_barrier() is unnecessary
anymore, remove it too.

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: move nat hlist_head to nf_conn

The nat extension structure is 32bytes in size on x86_64:

struct nf_conn_nat {
struct hlist_node bysource; /* 0 16 */
struct nf_conn * ct; /* 16 8 */
union nf_conntrack_nat_help help; /* 24 4 */
int masq_index; /* 28 4 */
/* size: 32, cachelines: 1, members: 4 */
/* last cacheline: 32 bytes */
};

The hlist is needed to quickly check for possible tuple collisions
when installing a new nat binding. Storing this in the extension
area has two drawbacks:

1. We need ct backpointer to get the conntrack struct from the extension.
2. When reallocation of extension area occurs we need to fixup the bysource
hash head via hlist_replace_rcu.

We can avoid both by placing the hlist_head in nf_conn and place nf_conn in
the bysource hash rather than the extenstion.

We can also remove the ->move support; no other extension needs it.

Moving the entire nat extension into nf_conn would be possible as well but
then we have to add yet another callback for deletion from the bysource
hash table rather than just using nat extension ->destroy hook for this.

nf_conn size doesn't increase due to aligment, followup patch replaces
hlist_node with single pointer.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

netfilter: nf_ct_ext: support variable length extensions

We can now define conntrack extensions of variable size. This
patch is useful to get rid of these unions:

union nf_conntrack_help
union nf_conntrack_proto
union nf_conntrack_nat_help

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net: reintroduce missing rcu_assign_pointer() calls

commit a9b3cd7f32 (rcu: convert uses of rcu_assign_pointer(x, NULL) to
RCU_INIT_POINTER) did a lot of incorrect changes, since it did a
complete conversion of rcu_assign_pointer(x, y) to RCU_INIT_POINTER(x,
y).

We miss needed barriers, even on x86, when y is not NULL.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Stephen Hemminger <shemminger@vyatta.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rcu: convert uses of rcu_assign_pointer(x, NULL) to RCU_INIT_POINTER

When assigning a NULL value to an RCU protected pointer, no barrier
is needed. The rcu_assign_pointer, used to handle that but will soon
change to not handle the special case.

Convert all rcu_assign_pointer of NULL value.

//smpl
@@ expression P; @@

- rcu_assign_pointer(P, NULL)
+ RCU_INIT_POINTER(P, NULL)

// </smpl>

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net,rcu: convert call_rcu(__nf_ct_ext_free_rcu) to kfree_rcu()

The rcu callback __nf_ct_ext_free_rcu() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(__nf_ct_ext_free_rcu).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

netfilter: rcu sparse cleanups

Use RCU helpers to reduce number of sparse warnings
(CONFIG_SPARSE_RCU_POINTER=y), and adds lockdep checks.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: ct_extend: fix the wrong alloc_size

In function update_alloc_size(), sizeof(struct nf_ct_ext) is added twice
wrongly.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: fix a race in nf_ct_ext_create()

As soon as rcu_read_unlock() is called, there is no guarantee current
thread can safely derefence t pointer, rcu protected.

Fix is to copy t->alloc_size in a temporary variable.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netfilter: __rcu annotations

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Patrick McHardy <kaber@trash.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

netfilter: nf_conntrack_extend: introduce __nf_ct_ext_exist()

some users of nf_ct_ext_exist() know ct->ext isn't NULL. For these users, the
check for ct->ext isn't necessary, the function __nf_ct_ext_exist() can be
used instead.

the type of the return value of nf_ct_ext_exist() is changed to bool.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: don't use INIT_RCU_HEAD()

call_rcu() will unconditionally reinitialize RCU head anyway.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

nf_conntrack: Use rcu_barrier()

RCU barriers, rcu_barrier(), is inserted two places.

In nf_conntrack_expect.c nf_conntrack_expect_fini() before the
kmem_cache_destroy(). Firstly to make sure the callback to the
nf_ct_expect_free_rcu() code is still around. Secondly because I'm
unsure about the consequence of having in flight
nf_ct_expect_free_rcu/kmem_cache_free() calls while doing a
kmem_cache_destroy() slab destroy.

And in nf_conntrack_extend.c nf_ct_extend_unregister(), inorder to
wait for completion of callbacks to __nf_ct_ext_free_rcu(), which is
invoked by __nf_ct_ext_add(). It might be more efficient to call
rcu_barrier() in nf_conntrack_core.c nf_conntrack_cleanup_net(), but
thats make it more difficult to read the code (as the callback code
in located in nf_conntrack_extend.c).

Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: Patrick McHardy <kaber@trash.net>

netfilter: nf_conntrack_extend: avoid unnecessary "ct->ext" dereferences

As Linus points out, "ct->ext" and "new" are always equal, avoid unnecessary
dereferences and use "new" directly.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: fix double-free and use-after free

As suggested by Patrick McHardy, introduce a __krealloc() that doesn't
free the original buffer to fix a double-free and use-after-free bug
introduced by me in netfilter that uses RCU.

Reported-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Tested-by: Dieter Ries <clip2@gmx.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: nf_nat: fix RCU races

Fix three ct_extend/NAT extension related races:

- When cleaning up the extension area and removing it from the bysource hash,
the nat->ct pointer must not be set to NULL since it may still be used in
a RCU read side

- When replacing a NAT extension area in the bysource hash, the nat->ct
pointer must be assigned before performing the replacement

- When reallocating extension storage in ct_extend, the old memory must
not be freed immediately since it may still be used by a RCU read side

Possibly fixes https://bugzilla.redhat.com/show_bug.cgi?id=449315
and/or http://bugzilla.kernel.org/show_bug.cgi?id=10875

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

netfilter: nf_conntrack_extend: use krealloc() in nf_conntrack_extend.c V2

The ksize() API is going away because it is being abused and it doesn't even
work consistenly across different allocators. Therefore, convert
net/netfilter/nf_conntrack_extend.c to use krealloc().

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: nf_conntrack_extend: warn on confirmed conntracks

New extensions may only be added to unconfirmed conntracks to avoid races
when reallocating the storage.

Also change NF_CT_ASSERT to use WARN_ON to get backtraces.

Signed-off-by: Patrick McHardy <kaber@trash.net>

[NETFILTER]: nf_conntrack: replace horrible hack with ksize()

There's a horrible slab abuse in net/netfilter/nf_conntrack_extend.c
that can be replaced with a call to ksize().

Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: nf_conntrack: fix ct_extend ->move operation

The ->move operation has two bugs:

- It is called with the same extension as source and destination,
so it doesn't update the new extension.

- The address of the old extension is calculated incorrectly,
instead of (void *)ct->ext + ct->ext->offset[i] it uses
ct->ext + ct->ext->offset[i].

Fixes a crash on x86_64 reported by Chuck Ebbert <cebbert@redhat.com>
and Thomas Woerner <twoerner@redhat.com>.

Tested-by: Thomas Woerner <twoerner@redhat.com>

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

[NETFILTER]: Fix NULL pointer dereference in nf_nat_move_storage()

Reported by Chuck Ebbert as:

https://bugzilla.redhat.com/show_bug.cgi?id=259501#c14

This routine is called each time hash should be replaced, nf_conn has
extension list which contains pointers to connection tracking users
(like nat, which is right now the only such user), so when replace takes
place it should copy own extensions. Loop above checks for own
extension, but tries to move higer-layer one, which can lead to above
oops.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

[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: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>