Some users are willing to provision huge amounts of memory to be able
to perform reassembly reasonnably well under pressure.

Current memory tracking is using one atomic_t and integers.

Switch to atomic_long_t so that 64bit arches can use more than 2GB,
without any cost for 32bit arches.

Note that this patch avoids an overflow error, if high_thresh was set
to ~2GB, since this test in inet_frag_alloc() was never true :

if (... || frag_mem_limit(nf) > nf->high_thresh)

Tested:

$ echo 16000000000 >/proc/sys/net/ipv4/ipfrag_high_thresh

<frag DDOS>

$ grep FRAG /proc/net/sockstat
FRAG: inuse 14705885 memory 16000002880

$ nstat -n ; sleep 1 ; nstat | grep Reas
IpReasmReqds                    3317150            0.0
IpReasmFails                    3317112            0.0

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 3e67f106f619dcfaf6f4e2039599bdb69848c714)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Some applications still rely on IP fragmentation, and to be fair linux
reassembly unit is not working under any serious load.

It uses static hash tables of 1024 buckets, and up to 128 items per bucket (!!!)

A work queue is supposed to garbage collect items when host is under memory
pressure, and doing a hash rebuild, changing seed used in hash computations.

This work queue blocks softirqs for up to 25 ms when doing a hash rebuild,
occurring every 5 seconds if host is under fire.

Then there is the problem of sharing this hash table for all netns.

It is time to switch to rhashtables, and allocate one of them per netns
to speedup netns dismantle, since this is a critical metric these days.

Lookup is now using RCU. A followup patch will even remove
the refcount hold/release left from prior implementation and save
a couple of atomic operations.

Before this patch, 16 cpus (16 RX queue NIC) could not handle more
than 1 Mpps frags DDOS.

After the patch, I reach 9 Mpps without any tuning, and can use up to 2GB
of storage for the fragments (exact number depends on frags being evicted
after timeout)

$ grep FRAG /proc/net/sockstat
FRAG: inuse 1966916 memory 2140004608

A followup patch will change the limits for 64bit arches.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Florian Westphal <fw@strlen.de>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Stefan Schmidt <stefan@osg.samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 648700f76b03b7e8149d13cc2bdb3355035258a9)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit 75d4e704fa8d2cf33ff295e5b441317603d7f9fd ]

Per discussion with David at netconf 2018, let's clarify
DaveM's position of handling stable backports in netdev-FAQ.

This is important for people relying on upstream -stable
releases.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit a61a86f8db92923a2a4c857c49a795bcae754497 ]

The SK_MEM_QUANTUM was changed from PAGE_SIZE to 4096. And the
tcp_wmem/tcp_rmem min default values are 4096.

Fixes: bd68a2a854ad ("net: set SK_MEM_QUANTUM to 4096")
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Should be "802.3ad" like everywhere else in the document.

Signed-off-by: Axel Beckert <abe@deuxchevaux.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull networking fixes from David Miller:

 1) Fix NAPI poll list corruption in enic driver, from Christian
    Lamparter.

 2) Fix route use after free, from Eric Dumazet.

 3) Fix regression in reuseaddr handling, from Josef Bacik.

 4) Assert the size of control messages in compat handling since we copy
    it in from userspace twice. From Meng Xu.

 5) SMC layer bug fixes (missing RCU locking, bad refcounting, etc.)
    from Ursula Braun.

 6) Fix races in AF_PACKET fanout handling, from Willem de Bruijn.

 7) Don't use ARRAY_SIZE on spinlock array which might have zero
    entries, from Geert Uytterhoeven.

 8) Fix miscomputation of checksum in ipv6 udp code, from Subash Abhinov
    Kasiviswanathan.

 9) Push the ipv6 header properly in ipv6 GRE tunnel driver, from Xin
    Long.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (75 commits)
  inet: fix improper empty comparison
  net: use inet6_rcv_saddr to compare sockets
  net: set tb->fast_sk_family
  net: orphan frags on stand-alone ptype in dev_queue_xmit_nit
  MAINTAINERS: update git tree locations for ieee802154 subsystem
  net: prevent dst uses after free
  net: phy: Fix truncation of large IRQ numbers in phy_attached_print()
  net/smc: no close wait in case of process shut down
  net/smc: introduce a delay
  net/smc: terminate link group if out-of-sync is received
  net/smc: longer delay for client link group removal
  net/smc: adapt send request completion notification
  net/smc: adjust net_device refcount
  net/smc: take RCU read lock for routing cache lookup
  net/smc: add receive timeout check
  net/smc: add missing dev_put
  net: stmmac: Cocci spatch "of_table"
  lan78xx: Use default values loaded from EEPROM/OTP after reset
  lan78xx: Allow EEPROM write for less than MAX_EEPROM_SIZE
  lan78xx: Fix for eeprom read/write when device auto suspend
  ...

Pull seccomp updates from Kees Cook:
 "Major additions:

   - sysctl and seccomp operation to discover available actions
     (tyhicks)

   - new per-filter configurable logging infrastructure and sysctl
     (tyhicks)

   - SECCOMP_RET_LOG to log allowed syscalls (tyhicks)

   - SECCOMP_RET_KILL_PROCESS as the new strictest possible action

   - self-tests for new behaviors"

[ This is the seccomp part of the security pull request during the merge
  window that was nixed due to unrelated problems   - Linus ]

* tag 'seccomp-v4.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  samples: Unrename SECCOMP_RET_KILL
  selftests/seccomp: Test thread vs process killing
  seccomp: Implement SECCOMP_RET_KILL_PROCESS action
  seccomp: Introduce SECCOMP_RET_KILL_PROCESS
  seccomp: Rename SECCOMP_RET_KILL to SECCOMP_RET_KILL_THREAD
  seccomp: Action to log before allowing
  seccomp: Filter flag to log all actions except SECCOMP_RET_ALLOW
  seccomp: Selftest for detection of filter flag support
  seccomp: Sysctl to configure actions that are allowed to be logged
  seccomp: Operation for checking if an action is available
  seccomp: Sysctl to display available actions
  seccomp: Provide matching filter for introspection
  selftests/seccomp: Refactor RET_ERRNO tests
  selftests/seccomp: Add simple seccomp overhead benchmark
  selftests/seccomp: Add tests for basic ptrace actions

Currently, writing into
net.ipv6.conf.all.{accept_dad,use_optimistic,optimistic_dad} has no effect.
Fix handling of these flags by:

- using the maximum of global and per-interface values for the
  accept_dad flag. That is, if at least one of the two values is
  non-zero, enable DAD on the interface. If at least one value is
  set to 2, enable DAD and disable IPv6 operation on the interface if
  MAC-based link-local address was found

- using the logical OR of global and per-interface values for the
  optimistic_dad flag. If at least one of them is set to one, optimistic
  duplicate address detection (RFC 4429) is enabled on the interface

- using the logical OR of global and per-interface values for the
  use_optimistic flag. If at least one of them is set to one,
  optimistic addresses won't be marked as deprecated during source address
  selection on the interface.

While at it, as we're modifying the prototype for ipv6_use_optimistic_addr(),
drop inline, and let the compiler decide.

Fixes: 7fd2561e4ebd ("net: ipv6: Add a sysctl to make optimistic addresses useful candidates")
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix ASCII art in Documentation/networking/switchdev.txt:

Change non-ASCII "spaces" to ASCII spaces.

Change 2 erroneous '+' characters in ASCII art to '-' (at the '*'
characters below):

line 32:
                     +--+----+----+----+-*--+----+---+  +-----+-----+
line 41:
                     +--------------+---*------------+

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix link in filter.txt.

Acked-by: Pavel Machek <pavel@ucw.cz>

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