On vxlan device create if socket create fails vxlan device is not
added to hash table. Therefore we need to check if device
is in hashtable before we delete it from hlist.
Following patch avoid the crash. net-next already has this fix.

---8<---
BUG: unable to handle kernel NULL pointer dereference at           (null)
IP: [<ffffffffa05f9ca7>] vxlan_dellink+0x77/0xf0 [vxlan]
PGD 42b2d9067 PUD 42e04c067 PMD 0
Oops: 0002 [#1] SMP
Modules linked in: vxlan(-)
Hardware name: Dell Inc. PowerEdge R620/0KCKR5, BIOS 1.4.8 10/25/2012
task: ffff88042ecf8760 ti: ffff88042f106000 task.ti: ffff88042f106000
RIP: 0010:[<ffffffffa05f9ca7>]  [<ffffffffa05f9ca7>]
vxlan_dellink+0x77/0xf0 [vxlan]
RSP: 0018:ffff88042f107e28  EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88082af08000 RCX: ffff88083fd80000
RDX: 0000000000000000 RSI: ffff88042f107e58 RDI: ffff88042e12f810
RBP: ffff88042f107e48 R08: ffffffff8166eca0 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88082af087c0
R13: ffff88042e12f000 R14: ffff88042f107e58 R15: ffff88042f107e58
FS:  00007f4ed2de7700(0000) GS:ffff88043fc80000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000042e076000 CR4: 00000000000407e0
Stack:
 ffff88082af08000 ffffffff81654848 ffffffffa05fb4e0 ffffffff81654780
 ffff88042f107e98 ffffffff813b9c7a ffff88042f107e58 ffff88042f107e58
 ffff88042f107e88 ffffffffa05fb4e0 ffffffffa05fb780 ffff88042f107f18
Call Trace:
 [<ffffffff813b9c7a>] __rtnl_link_unregister+0xca/0xd0
 [<ffffffff813bb0e9>] rtnl_link_unregister+0x19/0x30
 [<ffffffffa05faa4c>] vxlan_cleanup_module+0x10/0x2f [vxlan]
 [<ffffffff81099fef>] SyS_delete_module+0x1cf/0x2c0
 [<ffffffff8146c069>] ? do_page_fault+0x9/0x10
 [<ffffffff8146f012>] system_call_fastpath+0x16/0x1b
Code: 4d 85 ed 0f 84 95 00 00 00 4c 8d a7 c0 07 00 00 49 8d bd 10 08 00
00 e8 28 e8 e6 e0 48 8b 83 c0 07 00 00 49 8b 54 24 08 48 85 c0 <48> 89
02 74 04 48 89 50 08 49 b8 00 02 20 00 00 00 ad de 4d 89
RIP  [<ffffffffa05f9ca7>] vxlan_dellink+0x77/0xf0 [vxlan]
 RSP <ffff88042f107e28>
CR2: 0000000000000000
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is a regression introduced by:

	commit fe5c3561
	Author: stephen hemminger <stephen@networkplumber.org>
	Date:   Sat Jul 13 10:18:18 2013 -0700

	    vxlan: add necessary locking on device removal

The problem is that vxlan_dellink(), which is called with RTNL lock
held, tries to flush the workqueue synchronously, but apparently
igmp_join and igmp_leave work need to hold RTNL lock too, therefore we
have a soft lockup!

As suggested by Stephen, probably the flush_workqueue can just be
removed and let the normal refcounting work. The workqueue has a
reference to device and socket, therefore the cleanups should work
correctly.
Suggested-by: NStephen Hemminger <stephen@networkplumber.org>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: David S. Miller <davem@davemloft.net>
Tested-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NCong Wang <amwang@redhat.com>
Acked-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is a regression introduced by:

	commit 3fc2de2f
	Author: stephen hemminger <stephen@networkplumber.org>
	Date:   Thu Jul 18 08:40:15 2013 -0700

	    vxlan: fix igmp races

Before this commit, the old code was:

       if (vxlan_group_used(vn, vxlan->default_dst.remote_ip))
               ip_mc_join_group(sk, &mreq);
       else
               ip_mc_leave_group(sk, &mreq);

therefore we shoud check vxlan_group_used(), not its opposite,
for igmp_join.

Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are two race conditions in existing code for doing IGMP
management in workqueue in vxlan. First, the vxlan_group_used
function checks the list of vxlan's without any protection, and
it is possible for open followed by close to occur before the
igmp work queue runs.

To solve these move the check into vxlan_open/stop so it is
protected by RTNL. And split into two work structures so that
there is no racy reference to underlying device state.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix memory leaks and other badness from VXLAN network namespace
teardown. When network namespace is removed, all the vxlan devices should
be unregistered (not closed).
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Reviewed-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The socket management is now done in workqueue (outside of RTNL)
and protected by vn->sock_lock. There were two possible bugs, first
the vxlan device was removed from the VNI hash table per socket without
holding lock. And there was a race when device is created and the workqueue
could run after deletion.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

vxlan exit module unregisters vxlan net and then it unregisters
rtnl ops which triggers vxlan_dellink() from __rtnl_kill_links().
vxlan_dellink() deletes vxlan-dev from vxlan_list which has
list-head in vxlan-net-struct but that is already gone due to
net-unregister. That is how we are getting following crash.

Following commit fixes the crash by fixing module exit path.

BUG: unable to handle kernel paging request at ffff8804102c8000
IP: [<ffffffff812cc5e9>] __list_del_entry+0x29/0xd0
PGD 2972067 PUD 83e019067 PMD 83df97067 PTE 80000004102c8060
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
Modules linked in: ---
CPU: 19 PID: 6712 Comm: rmmod Tainted: GF            3.10.0+ #95
Hardware name: Dell Inc. PowerEdge R620/0KCKR5, BIOS 1.4.8 10/25/2012
task: ffff88080c47c580 ti: ffff88080ac50000 task.ti: ffff88080ac50000
RIP: 0010:[<ffffffff812cc5e9>]  [<ffffffff812cc5e9>]
__list_del_entry+0x29/0xd0
RSP: 0018:ffff88080ac51e08  EFLAGS: 00010206
RAX: ffff8804102c8000 RBX: ffff88040f0d4b10 RCX: dead000000200200
RDX: ffff8804102c8000 RSI: ffff88080ac51e58 RDI: ffff88040f0d4b10
RBP: ffff88080ac51e08 R08: 0000000000000001 R09: 2222222222222222
R10: 2222222222222222 R11: 2222222222222222 R12: ffff88080ac51e58
R13: ffffffffa07b8840 R14: ffffffff81ae48c0 R15: ffff88080ac51e58
FS:  00007f9ef105c700(0000) GS:ffff88082a800000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff8804102c8000 CR3: 00000008227e5000 CR4: 00000000000407e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Stack:
 ffff88080ac51e28 ffffffff812cc6a1 2222222222222222 ffff88040f0d4000
 ffff88080ac51e48 ffffffffa07b3311 ffff88040f0d4000 ffffffff81ae49c8
 ffff88080ac51e98 ffffffff81492fc2 ffff88080ac51e58 ffff88080ac51e58
Call Trace:
 [<ffffffff812cc6a1>] list_del+0x11/0x40
 [<ffffffffa07b3311>] vxlan_dellink+0x51/0x70 [vxlan]
 [<ffffffff81492fc2>] __rtnl_link_unregister+0xa2/0xb0
 [<ffffffff8149448e>] rtnl_link_unregister+0x1e/0x30
 [<ffffffffa07b7b7c>] vxlan_cleanup_module+0x1c/0x2f [vxlan]
 [<ffffffff810c9b31>] SyS_delete_module+0x1d1/0x2c0
 [<ffffffff812b8a0e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
 [<ffffffff81582f42>] system_call_fastpath+0x16/0x1b
Code: eb 9f 55 48 8b 17 48 b9 00 01 10 00 00 00 ad de 48 8b 47 08 48 89
e5 48 39 ca 74 29 48 b9 00 02 20 00 00 00 ad de 48 39 c8 74 7a <4c> 8b
00 4c 39 c7 75 53 4c 8b 42 08 4c 39 c7 75 2b 48 89 42 08
RIP  [<ffffffff812cc5e9>] __list_del_entry+0x29/0xd0
 RSP <ffff88080ac51e08>
CR2: ffff8804102c8000
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

The zero MAC entry in the fdb is used as default destination. With
multiple default destinations it is possible to use vxlan in
environments that disable multicast on the infrastructure level, e.g.
public clouds.
Signed-off-by: NMike Rapoport <mike.rapoport@ravellosystems.com>
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

When the last item is deleted from the remote destinations list, the
fdb entry is destroyed.
Signed-off-by: NMike Rapoport <mike.rapoport@ravellosystems.com>
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

which will be reused by vxlan_fdb_delete
Signed-off-by: NMike Rapoport <mike.rapoport@ravellosystems.com>
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

which will be reused by vxlan_fdb_delete
Signed-off-by: NMike Rapoport <mike.rapoport@ravellosystems.com>
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

Signed-off-by: NMike Rapoport <mike.rapoport@ravellosystems.com>
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

Fix following sparse warnings.
drivers/net/vxlan.c:238:44: warning: incorrect type in argument 3 (different base types)
drivers/net/vxlan.c:238:44:    expected restricted __be32 [usertype] value
drivers/net/vxlan.c:238:44:    got unsigned int const [unsigned] [usertype] remote_vni
drivers/net/vxlan.c:1735:18: warning: incorrect type in initializer (different signedness)
drivers/net/vxlan.c:1735:18:    expected int *id
drivers/net/vxlan.c:1735:18:    got unsigned int static [toplevel] *<noident>
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

Fix whitespace and spelling
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Acked-by: NDavid L Stevens <dlstevens@us.ibm.com>

For the notification code, a couple of places build fdb entries on
the stack, use structure initialization instead and fix formatting.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

UDP ports are limited to 16 bits.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

Based on initial work by Mike Rapoport <mike.rapoport@ravellosystems.com>
Use list macros and RCU for tracking multiple remotes.

Note: this code assumes list always has at least one entry,
because delete is not supported.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

The function vxlan_xmit_one always returns NETDEV_TX_OK, so there
is no point in keeping track of return values etc.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Acked-by: NDavid L Stevens <dlstevens@us.ibm.com>

Put destruction of per-cpu statistics removal in
ndo_uninit since it is created by ndo_init.
This also avoids any problems that might be cause by destructor
being called after module removed.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

It is possible for two cpu's to race creating vxlan device.
For most cases this is harmless, but the ability to assign "next
avaliable vxlan device" relies on rtnl lock being held across the
whole operation. Therfore two instances of calling:
  ip li add vxlan%d vxlan ...
could collide and create two devices with same name.

To fix this defer creation of socket to a work queue, and
handle possible races there. Introduce a lock to ensure that
changes to vxlan socket hash list is SMP safe.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

When learned entry migrates to another IP send a notification
that entry has changed.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

Do join/leave from work queue to avoid lock inversion problems
between normal socket and RTNL. The code comes out cleaner
as well.

Uses Cong Wang's suggestion to turn refcnt into a real atomic
since now need to handle case where last use of socket is IGMP
worker.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

Switch to using a per module work queue so that all the socket
deletion callbacks are done when module is removed.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

If vxlan is removed with active vxlan's it would crash because
rtnl_link_unregister (which calls vxlan_dellink), was invoked
before unregister_pernet_device (which calls vxlan_stop).
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>

Refactor various ip tunnels xmit functions and extend iptunnel_xmit()
so that there is more code sharing.
Signed-off-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The check introduced by:
	commit 26a41ae6
	Author: stephen hemminger <stephen@networkplumber.org>
	Date:   Mon Jun 17 12:09:58 2013 -0700

	    vxlan: only migrate dynamic FDB entries

was not correct because it is checking flag about type of FDB
entry, rather than the state (dynamic versus static). The confusion
arises because vxlan is reusing values from bridge, and bridge is
reusing values from neighbour table, and easy to get lost in translation.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If skb_clone fails if out of memory then just skip the fanout.

Problem was introduced in 3.10 with:
  commit 6681712d
  Author: David Stevens <dlstevens@us.ibm.com>
  Date:   Fri Mar 15 04:35:51 2013 +0000

    vxlan: generalize forwarding tables
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Only migrate dynamic forwarding table entries, don't modify
static entries. If packet received from incorrect source IP address
assume it is an imposter and drop it.

This patch applies only to -net, a different patch would be needed for earlier
kernels since the NTF_SELF flag was introduced with 3.10.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is possible for a packet to arrive during vxlan_stop(), and
have a dynamic entry created. Close this by checking if device
is up.

 CPU1                             CPU2
vxlan_stop
  vxlan_flush
     hash_lock acquired
                                  vxlan_encap_recv
                                     vxlan_snoop
                                        waiting for hash_lock
     hash_lock relased
  vxlan_flush done
                                        hash_lock acquired
                                        vxlan_fdb_create

This is a day-one bug in vxlan goes back to 3.7.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When vxlan is compiled as builtin, its init code
runs before IPv6 init, this could cause problems
if we create IPv6 socket in the latter patch.

Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

'unsigned int' is slightly better.

Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NCong Wang <amwang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: NCong Wang <amwang@redhat.com>
Acked-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix some instances where vxlan fdb 'used' field is not updated after the entry
is used.

v2: rename vxlan_find_mac() as __vxlan_find_mac() and create a new vxlan_find_mac()
that also updates ->used field.
Signed-off-by: NSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The commit 823aa873
  Author: stephen hemminger <stephen@networkplumber.org>
  Date:   Sat Apr 27 11:31:57 2013 +0000

    vxlan: allow choosing destination port per vxlan

introduced per-vxlan UDP port configuration but only did half of the
necessary work.  It added per vxlan destination for sending, but
overlooked the handling of multiple ports for incoming traffic.

This patch changes the listening port management to handle multiple
incoming UDP ports. The earlier per-namespace structure is now a hash
list per namespace.

It is also now possible to define the same virtual network id
but with different UDP port values which can be useful for migration.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since SKB_GSO_* flags are set by appropriate gso_segment callback
in TCP/UDP layer.

CC: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: NDmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: NEilon Greenstein <eilong@broadcom.com>
Acked-by: NPravin B Shelar <pshelar@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Allow configuring the default destination port on a per-device basis.
Adds new netlink paramater IFLA_VXLAN_PORT to allow setting destination
port when creating new vxlan.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rather than computing source port and returning it in host order
then swapping later, go ahead and compute it in network order to
start with. Cleaner and less error prone.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Source compatiability for build iproute2 was broken by:
  commit c7995c43
  Author: Atzm Watanabe <atzm@stratosphere.co.jp>
    vxlan: Allow setting destination to unicast address.

Since this commit has not made it upstream (still net-next),
and better to avoid gratitious changes to exported API's;
go back to original definition, and add a comment.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The NDA_PORT attribute was added, but the author wasn't careful
about width (port is 16 bits), or byte order.  The attribute was
being dumped as 16 bits, but only 32 bit value would be accepted
when setting up a device. Also, the remote port is in network
byte order and was being compared with default port in host byte
order.
Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>