[NETFILTER]: nfnetlink_queue: fix computation of allocated size for netlink skb.

Size of the netlink skb was wrongly computed because the formula was using
NLMSG_ALIGN instead of NLMSG_SPACE. NLMSG_ALIGN does not add the room for
netlink header as NLMSG_SPACE does. This was causing a failure of message
building in some cases.

On my test system, all messages for packets in range [8*k+41, 8*k+48] where k
is an integer were invalid and the corresponding packets were dropped.
Signed-off-by: NEric Leblond <eric@inl.fr>
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/netfilter/nfnetlink_queue.c

@@ -224,7 +224,7 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,
 	struct net_device *indev;
 	struct net_device *outdev;
 
-	size =    NLMSG_ALIGN(sizeof(struct nfgenmsg))
+	size =    NLMSG_SPACE(sizeof(struct nfgenmsg))
 		+ nla_total_size(sizeof(struct nfqnl_msg_packet_hdr))
 		+ nla_total_size(sizeof(u_int32_t))	/* ifindex */
 		+ nla_total_size(sizeof(u_int32_t))	/* ifindex */