Use kmem_cache to allocate/free inet_frag_queue objects since they're
all the same size per inet_frags user and are alloced/freed in high volumes
thus making it a perfect case for kmem_cache.

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

The last_in field has been used to store various flags different from
first/last frag in so give it a more descriptive name: flags.

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch makes init_net's high_thresh limit to be the maximum for all
namespaces, thus introducing a global memory limit threshold equal to the
sum of the individual high_thresh limits which are capped.
It also introduces some sane minimums for low_thresh as it shouldn't be
able to drop below 0 (or > high_thresh in the unsigned case), and
overall low_thresh should not ever be above high_thresh, so we make the
following relations for a namespace:
init_net:
 high_thresh - max(not capped), min(init_net low_thresh)
 low_thresh - max(init_net high_thresh), min (0)

all other namespaces:
 high_thresh = max(init_net high_thresh), min(namespace's low_thresh)
 low_thresh = max(namespace's high_thresh), min(0)

The major issue with having low_thresh > high_thresh is that we'll
schedule eviction but never evict anything and thus rely only on the
timers.

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rehash is rare operation, don't force readers to take
the read-side rwlock.

Instead, we only have to detect the (rare) case where
the secret was altered while we are trying to insert
a new inetfrag queue into the table.

If it was changed, drop the bucket lock and recompute
the hash to get the 'new' chain bucket that we have to
insert into.

Joint work with Nikolay Aleksandrov.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

merge functionality into the eviction workqueue.

Instead of rebuilding every n seconds, take advantage of the upper
hash chain length limit.

If we hit it, mark table for rebuild and schedule workqueue.
To prevent frequent rebuilds when we're completely overloaded,
don't rebuild more than once every 5 seconds.

ipfrag_secret_interval sysctl is now obsolete and has been marked as
deprecated, it still can be changed so scripts won't be broken but it
won't have any effect. A comment is left above each unused secret_timer
variable to avoid confusion.

Joint work with Nikolay Aleksandrov.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

no longer used.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

First step to move eviction handling into a work queue.

We lose two spots that accounted evicted fragments in MIB counters.

Accounting will be restored since the upcoming work-queue evictor
invokes the frag queue timer callbacks instead.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

hide actual hash size from individual users: The _find
function will now fold the given hash value into the required range.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pablo Neira Ayuso says:

====================
Netfilter updates for net-next

The following patchset contains updates for your net-next tree,
they are:

1) Use kvfree() helper function from x_tables, from Eric Dumazet.

2) Remove extra timer from the conntrack ecache extension, use a
   workqueue instead to redeliver lost events to userspace instead,
   from Florian Westphal.

3) Removal of the ulog targets for ebtables and iptables. The nflog
   infrastructure superseded this almost 9 years ago, time to get rid
   of this code.

4) Replace the list of loggers by an array now that we can only have
   two possible non-overlapping logger flavours, ie. kernel ring buffer
   and netlink logging.

5) Move Eric Dumazet's log buffer code to nf_log to reuse it from
   all of the supported per-family loggers.

6) Consolidate nf_log_packet() as an unified interface for packet logging.
   After this patch, if the struct nf_loginfo is available, it explicitly
   selects the logger that is used.

7) Move ip and ip6 logging code from xt_LOG to the corresponding
   per-family loggers. Thus, x_tables and nf_tables share the same code
   for packet logging.

8) Add generic ARP packet logger, which is used by nf_tables. The
   format aims to be consistent with the output of xt_LOG.

9) Add generic bridge packet logger. Again, this is used by nf_tables
   and it routes the packets to the real family loggers. As a result,
   we get consistent logging format for the bridge family. The ebt_log
   logging code has been intentionally left in place not to break
   backward compatibility since the logging output differs from xt_LOG.

10) Update nft_log to explicitly request the required family logger when
    needed.

11) Finish nft_log so it supports arp, ip, ip6, bridge and inet families.
    Allowing selection between netlink and kernel buffer ring logging.

12) Several fixes coming after the netfilter core logging changes spotted
    by robots.

13) Use IS_ENABLED() macros whenever possible in the netfilter tree,
    from Duan Jiong.

14) Removal of a couple of unnecessary branch before kfree, from Fabian
    Frederick.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>