TCP listener refactoring, part 4 :

To speed up inet lookups, we moved IPv4 addresses from inet to struct
sock_common

Now is time to do the same for IPv6, because it permits us to have fast
lookups for all kind of sockets, including upcoming SYN_RECV.

Getting IPv6 addresses in TCP lookups currently requires two extra cache
lines, plus a dereference (and memory stall).

inet6_sk(sk) does the dereference of inet_sk(__sk)->pinet6

This patch is way bigger than its IPv4 counter part, because for IPv4,
we could add aliases (inet_daddr, inet_rcv_saddr), while on IPv6,
it's not doable easily.

inet6_sk(sk)->daddr becomes sk->sk_v6_daddr
inet6_sk(sk)->rcv_saddr becomes sk->sk_v6_rcv_saddr

And timewait socket also have tw->tw_v6_daddr & tw->tw_v6_rcv_saddr
at the same offset.

We get rid of INET6_TW_MATCH() as INET6_MATCH() is now the generic
macro.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/l2tp/l2tp_core.c: In function ‘l2tp_verify_udp_checksum’:
net/l2tp/l2tp_core.c:499:22: warning: unused variable ‘tunnel’ [-Wunused-variable]

Create a helper "l2tp_tunnel()" to facilitate this, and as a side
effect get rid of a bunch of unnecessary void pointer casts.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IPv4 mapped addresses cause kernel panic.
The patch juste check whether the IPv6 address is an IPv4 mapped
address. If so, use IPv4 API instead of IPv6.

[  940.026915] general protection fault: 0000 [#1]
[  940.026915] Modules linked in: l2tp_ppp l2tp_netlink l2tp_core pppox ppp_generic slhc loop psmouse
[  940.026915] CPU: 0 PID: 3184 Comm: memcheck-amd64- Not tainted 3.11.0+ #1
[  940.026915] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[  940.026915] task: ffff880007130e20 ti: ffff88000737e000 task.ti: ffff88000737e000
[  940.026915] RIP: 0010:[<ffffffff81333780>]  [<ffffffff81333780>] ip6_xmit+0x276/0x326
[  940.026915] RSP: 0018:ffff88000737fd28  EFLAGS: 00010286
[  940.026915] RAX: c748521a75ceff48 RBX: ffff880000c30800 RCX: 0000000000000000
[  940.026915] RDX: ffff88000075cc4e RSI: 0000000000000028 RDI: ffff8800060e5a40
[  940.026915] RBP: ffff8800060e5a40 R08: 0000000000000000 R09: ffff88000075cc90
[  940.026915] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88000737fda0
[  940.026915] R13: 0000000000000000 R14: 0000000000002000 R15: ffff880005d3b580
[  940.026915] FS:  00007f163dc5e800(0000) GS:ffffffff81623000(0000) knlGS:0000000000000000
[  940.026915] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  940.026915] CR2: 00000004032dc940 CR3: 0000000005c25000 CR4: 00000000000006f0
[  940.026915] Stack:
[  940.026915]  ffff88000075cc4e ffffffff81694e90 ffff880000c30b38 0000000000000020
[  940.026915]  11000000523c4bac ffff88000737fdb4 0000000000000000 ffff880000c30800
[  940.026915]  ffff880005d3b580 ffff880000c30b38 ffff8800060e5a40 0000000000000020
[  940.026915] Call Trace:
[  940.026915]  [<ffffffff81356cc3>] ? inet6_csk_xmit+0xa4/0xc4
[  940.026915]  [<ffffffffa0038535>] ? l2tp_xmit_skb+0x503/0x55a [l2tp_core]
[  940.026915]  [<ffffffff812b8d3b>] ? pskb_expand_head+0x161/0x214
[  940.026915]  [<ffffffffa003e91d>] ? pppol2tp_xmit+0xf2/0x143 [l2tp_ppp]
[  940.026915]  [<ffffffffa00292e0>] ? ppp_channel_push+0x36/0x8b [ppp_generic]
[  940.026915]  [<ffffffffa00293fe>] ? ppp_write+0xaf/0xc5 [ppp_generic]
[  940.026915]  [<ffffffff8110ead4>] ? vfs_write+0xa2/0x106
[  940.026915]  [<ffffffff8110edd6>] ? SyS_write+0x56/0x8a
[  940.026915]  [<ffffffff81378ac0>] ? system_call_fastpath+0x16/0x1b
[  940.026915] Code: 00 49 8b 8f d8 00 00 00 66 83 7c 11 02 00 74 60 49
8b 47 58 48 83 e0 fe 48 8b 80 18 01 00 00 48 85 c0 74 13 48 8b 80 78 02
00 00 <48> ff 40 28 41 8b 57 68 48 01 50 30 48 8b 54 24 08 49 c7 c1 51
[  940.026915] RIP  [<ffffffff81333780>] ip6_xmit+0x276/0x326
[  940.026915]  RSP <ffff88000737fd28>
[  940.057945] ---[ end trace be8aba9a61c8b7f3 ]---
[  940.058583] Kernel panic - not syncing: Fatal exception in interrupt
Signed-off-by: NFrançois CACHEREUL <f.cachereul@alphalink.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If L2TP data sequence numbers are enabled and reordering is not
enabled, data reception stops if a packet is lost since the kernel
waits for a sequence number that is never resent. (When reordering is
enabled, data reception restarts when the reorder timeout expires.) If
no reorder timeout is set, we should count the number of in-sequence
packets after the out-of-sequence (OOS) condition is detected, and reset
sequence number state after a number of such packets are received.

For now, the number of in-sequence packets while in OOS state which
cause the sequence number state to be reset is hard-coded to 5. This
could be configurable later.
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The L2TP datapath is not currently RFC-compliant when sequence numbers
are used in L2TP data packets. According to the L2TP RFC, any received
sequence number NR greater than or equal to the next expected NR is
acceptable, where the "greater than or equal to" test is determined by
the NR wrap point. This differs for L2TPv2 and L2TPv3, so add state in
the session context to hold the max NR value and the NR window size in
order to do the acceptable sequence number value check. These might be
configurable later, but for now we derive it from the tunnel L2TP
version, which determines the sequence number field size.
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This change moves some code handling data sequence numbers into a
separate function to avoid too much indentation. This is to prepare
for some changes to data sequence number handling in subsequent
patches.
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is a cut and paste typo.  We call ->ref() a second time instead
of ->deref().
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If we postpone unhashing of l2tp sessions until the structure is freed, we
risk:

 1. further packets arriving and getting queued while the pseudowire is being
    closed down
 2. the recv path hitting "scheduling while atomic" errors in the case that
    recv drops the last reference to a session and calls l2tp_session_free
    while in atomic context

As such, l2tp sessions should be unhashed from l2tp_core data structures early
in the teardown process prior to calling pseudowire close.  For pseudowires
like l2tp_ppp which have multiple shutdown codepaths, provide an unhash hook.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

l2tp's u64_stats writers were incorrectly synchronised, making it possible to
deadlock a 64bit machine running a 32bit kernel simply by sending the l2tp
code netlink commands while passing data through l2tp sessions.

Previous discussion on netdev determined that alternative solutions such as
spinlock writer synchronisation or per-cpu data would bring unjustified
overhead, given that most users interested in high volume traffic will likely
be running 64bit kernels on 64bit hardware.

As such, this patch replaces l2tp's use of u64_stats with atomic_long_t,
thereby avoiding the deadlock.

Ref:
http://marc.info/?l=linux-netdev&m=134029167910731&w=2
http://marc.info/?l=linux-netdev&m=134079868111131&w=2Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add calls to l2tp_session_queue_purge as a part of l2tp_tunnel_closeall
and l2tp_session_delete.  Pseudowire implementations which are deleted only
via. l2tp_core l2tp_session_delete calls can dispense with their own code for
flushing the reorder queue.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If an l2tp session is deleted, it is necessary to delete skbs in-flight
on the session's reorder queue before taking it down.

Rather than having each pseudowire implementation reaching into the
l2tp_session struct to handle this itself, provide a function in l2tp_core to
purge the session queue.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is valid for an existing struct sock object to have a NULL sk_socket
pointer, so don't BUG_ON in l2tp_tunnel_del_work if that should occur.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When looking up the tunnel socket in struct l2tp_tunnel, hold a reference
whether the socket was created by the kernel or by userspace.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a user deletes a tunnel using netlink, all the sessions in the tunnel
should also be deleted.  Since running sessions will pin the tunnel socket
with the references they hold, have the l2tp_tunnel_delete close all sessions
in a tunnel before finally closing the tunnel socket.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

l2tp_core internally uses l2tp_tunnel_closeall to close all sessions in a
tunnel when a UDP-encapsulation socket is destroyed.  We need to do something
similar for IP-encapsulation sockets.

Export l2tp_tunnel_closeall as a GPL symbol to enable l2tp_ip and l2tp_ip6 to
call it from their .destroy handlers.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

L2TP sessions hold a reference to the tunnel socket to prevent it going away
while sessions are still active.  However, since tunnel destruction is handled
by the sock sk_destruct callback there is a catch-22: a tunnel with sessions
cannot be deleted since each session holds a reference to the tunnel socket.
If userspace closes a managed tunnel socket, or dies, the tunnel will persist
and it will be neccessary to individually delete the sessions using netlink
commands.  This is ugly.

To prevent this occuring, this patch leverages the udp encapsulation socket
destroy callback to gain early notification when the tunnel socket is closed.
This allows us to safely close the sessions running in the tunnel, dropping
the tunnel socket references in the process.  The tunnel socket is then
destroyed as normal, and the tunnel resources deallocated in sk_destruct.

While we're at it, ensure that l2tp_tunnel_closeall correctly drops session
references to allow the sessions to be deleted rather than leaking.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I'm not sure why, but the hlist for each entry iterators were conceived

        list_for_each_entry(pos, head, member)

The hlist ones were greedy and wanted an extra parameter:

        hlist_for_each_entry(tpos, pos, head, member)

Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.

Besides the semantic patch, there was some manual work required:

 - Fix up the actual hlist iterators in linux/list.h
 - Fix up the declaration of other iterators based on the hlist ones.
 - A very small amount of places were using the 'node' parameter, this
 was modified to use 'obj->member' instead.
 - Coccinelle didn't handle the hlist_for_each_entry_safe iterator
 properly, so those had to be fixed up manually.

The semantic patch which is mostly the work of Peter Senna Tschudin is here:

@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;

type T;
expression a,c,d,e;
identifier b;
statement S;
@@

-T b;
    <+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
    ...+>

[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: NPeter Senna Tschudin <peter.senna@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Andrew Savchenko reported a DNS failure and we diagnosed that
some UDP sockets were unable to send more packets because their
sk_wmem_alloc was corrupted after a while (tx_queue column in
following trace)

$ cat /proc/net/udp
  sl  local_address rem_address   st tx_queue rx_queue tr tm->when retrnsmt   uid  timeout inode ref pointer drops
...
  459: 00000000:0270 00000000:0000 07 00000000:00000000 00:00000000 00000000     0        0 4507 2 ffff88003d612380 0
  466: 00000000:0277 00000000:0000 07 00000000:00000000 00:00000000 00000000     0        0 4802 2 ffff88003d613180 0
  470: 076A070A:007B 00000000:0000 07 FFFF4600:00000000 00:00000000 00000000   123        0 5552 2 ffff880039974380 0
  470: 010213AC:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000     0        0 4986 2 ffff88003dbd3180 0
  470: 010013AC:007B 00000000:0000 07 00000000:00000000 00:00000000 00000000     0        0 4985 2 ffff88003dbd2e00 0
  470: 00FCA8C0:007B 00000000:0000 07 FFFFFB00:00000000 00:00000000 00000000     0        0 4984 2 ffff88003dbd2a80 0
...

Playing with skb->truesize is tricky, especially when
skb is attached to a socket, as we can fool memory charging.

Just remove this code, its not worth trying to be ultra
precise in xmit path.
Reported-by: NAndrew Savchenko <bircoph@gmail.com>
Tested-by: NAndrew Savchenko <bircoph@gmail.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: James Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When creating unmanaged tunnel sockets we should honour the network namespace
passed to l2tp_tunnel_create.  Furthermore, unmanaged tunnel sockets should
not hold a reference to the network namespace lest they accidentally keep
alive a namespace which should otherwise have been released.

Unmanaged tunnel sockets now drop their namespace reference via sk_change_net,
and are released in a new pernet exit callback, l2tp_exit_net.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

l2tp_tunnel_create is passed a pointer to the network namespace for the
tunnel, along with an optional file descriptor for the tunnel which may
be passed in from userspace via. netlink.

In the case where the file descriptor is defined, ensure that the namespace
associated with that socket matches the namespace explicitly passed to
l2tp_tunnel_create.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To allow l2tp_tunnel_delete to be called from an atomic context, place the
tunnel socket release calls on a workqueue for asynchronous execution.

Tunnel memory is eventually freed in the tunnel socket destructor.
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If a tunnel socket is created by userspace, l2tp hooks the socket destructor
in order to clean up resources if userspace closes the socket or crashes.  It
also caches a pointer to the struct sock for use in the data path and in the
netlink interface.

While it is safe to use the cached sock pointer in the data path, where the
skb references keep the socket alive, it is not safe to use it elsewhere as
such access introduces a race with userspace closing the socket.  In
particular, l2tp_tunnel_delete is prone to oopsing if a multithreaded
userspace application closes a socket at the same time as sending a netlink
delete command for the tunnel.

This patch fixes this oops by forcing l2tp_tunnel_delete to explicitly look up
a tunnel socket held by userspace using sockfd_lookup().
Signed-off-by: NTom Parkin <tparkin@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes following lockdep splat :

[ 1614.734896] =============================================
[ 1614.734898] [ INFO: possible recursive locking detected ]
[ 1614.734901] 3.6.0-rc3+ #782 Not tainted
[ 1614.734903] ---------------------------------------------
[ 1614.734905] swapper/11/0 is trying to acquire lock:
[ 1614.734907]  (slock-AF_INET){+.-...}, at: [<ffffffffa0209d72>] l2tp_xmit_skb+0x172/0xa50 [l2tp_core]
[ 1614.734920]
[ 1614.734920] but task is already holding lock:
[ 1614.734922]  (slock-AF_INET){+.-...}, at: [<ffffffff815fce23>] tcp_v4_err+0x163/0x6b0
[ 1614.734932]
[ 1614.734932] other info that might help us debug this:
[ 1614.734935]  Possible unsafe locking scenario:
[ 1614.734935]
[ 1614.734937]        CPU0
[ 1614.734938]        ----
[ 1614.734940]   lock(slock-AF_INET);
[ 1614.734943]   lock(slock-AF_INET);
[ 1614.734946]
[ 1614.734946]  *** DEADLOCK ***
[ 1614.734946]
[ 1614.734949]  May be due to missing lock nesting notation
[ 1614.734949]
[ 1614.734952] 7 locks held by swapper/11/0:
[ 1614.734954]  #0:  (rcu_read_lock){.+.+..}, at: [<ffffffff81592801>] __netif_receive_skb+0x251/0xd00
[ 1614.734964]  #1:  (rcu_read_lock){.+.+..}, at: [<ffffffff815d319c>] ip_local_deliver_finish+0x4c/0x4e0
[ 1614.734972]  #2:  (rcu_read_lock){.+.+..}, at: [<ffffffff8160d116>] icmp_socket_deliver+0x46/0x230
[ 1614.734982]  #3:  (slock-AF_INET){+.-...}, at: [<ffffffff815fce23>] tcp_v4_err+0x163/0x6b0
[ 1614.734989]  #4:  (rcu_read_lock){.+.+..}, at: [<ffffffff815da240>] ip_queue_xmit+0x0/0x680
[ 1614.734997]  #5:  (rcu_read_lock_bh){.+....}, at: [<ffffffff815d9925>] ip_finish_output+0x135/0x890
[ 1614.735004]  #6:  (rcu_read_lock_bh){.+....}, at: [<ffffffff81595680>] dev_queue_xmit+0x0/0xe00
[ 1614.735012]
[ 1614.735012] stack backtrace:
[ 1614.735016] Pid: 0, comm: swapper/11 Not tainted 3.6.0-rc3+ #782
[ 1614.735018] Call Trace:
[ 1614.735020]  <IRQ>  [<ffffffff810a50ac>] __lock_acquire+0x144c/0x1b10
[ 1614.735033]  [<ffffffff810a334b>] ? check_usage+0x9b/0x4d0
[ 1614.735037]  [<ffffffff810a6762>] ? mark_held_locks+0x82/0x130
[ 1614.735042]  [<ffffffff810a5df0>] lock_acquire+0x90/0x200
[ 1614.735047]  [<ffffffffa0209d72>] ? l2tp_xmit_skb+0x172/0xa50 [l2tp_core]
[ 1614.735051]  [<ffffffff810a69ad>] ? trace_hardirqs_on+0xd/0x10
[ 1614.735060]  [<ffffffff81749b31>] _raw_spin_lock+0x41/0x50
[ 1614.735065]  [<ffffffffa0209d72>] ? l2tp_xmit_skb+0x172/0xa50 [l2tp_core]
[ 1614.735069]  [<ffffffffa0209d72>] l2tp_xmit_skb+0x172/0xa50 [l2tp_core]
[ 1614.735075]  [<ffffffffa014f7f2>] l2tp_eth_dev_xmit+0x32/0x60 [l2tp_eth]
[ 1614.735079]  [<ffffffff81595112>] dev_hard_start_xmit+0x502/0xa70
[ 1614.735083]  [<ffffffff81594c6e>] ? dev_hard_start_xmit+0x5e/0xa70
[ 1614.735087]  [<ffffffff815957c1>] ? dev_queue_xmit+0x141/0xe00
[ 1614.735093]  [<ffffffff815b622e>] sch_direct_xmit+0xfe/0x290
[ 1614.735098]  [<ffffffff81595865>] dev_queue_xmit+0x1e5/0xe00
[ 1614.735102]  [<ffffffff81595680>] ? dev_hard_start_xmit+0xa70/0xa70
[ 1614.735106]  [<ffffffff815b4daa>] ? eth_header+0x3a/0xf0
[ 1614.735111]  [<ffffffff8161d33e>] ? fib_get_table+0x2e/0x280
[ 1614.735117]  [<ffffffff8160a7e2>] arp_xmit+0x22/0x60
[ 1614.735121]  [<ffffffff8160a863>] arp_send+0x43/0x50
[ 1614.735125]  [<ffffffff8160b82f>] arp_solicit+0x18f/0x450
[ 1614.735132]  [<ffffffff8159d9da>] neigh_probe+0x4a/0x70
[ 1614.735137]  [<ffffffff815a191a>] __neigh_event_send+0xea/0x300
[ 1614.735141]  [<ffffffff815a1c93>] neigh_resolve_output+0x163/0x260
[ 1614.735146]  [<ffffffff815d9cf5>] ip_finish_output+0x505/0x890
[ 1614.735150]  [<ffffffff815d9925>] ? ip_finish_output+0x135/0x890
[ 1614.735154]  [<ffffffff815dae79>] ip_output+0x59/0xf0
[ 1614.735158]  [<ffffffff815da1cd>] ip_local_out+0x2d/0xa0
[ 1614.735162]  [<ffffffff815da403>] ip_queue_xmit+0x1c3/0x680
[ 1614.735165]  [<ffffffff815da240>] ? ip_local_out+0xa0/0xa0
[ 1614.735172]  [<ffffffff815f4402>] tcp_transmit_skb+0x402/0xa60
[ 1614.735177]  [<ffffffff815f5a11>] tcp_retransmit_skb+0x1a1/0x620
[ 1614.735181]  [<ffffffff815f7e93>] tcp_retransmit_timer+0x393/0x960
[ 1614.735185]  [<ffffffff815fce23>] ? tcp_v4_err+0x163/0x6b0
[ 1614.735189]  [<ffffffff815fd317>] tcp_v4_err+0x657/0x6b0
[ 1614.735194]  [<ffffffff8160d116>] ? icmp_socket_deliver+0x46/0x230
[ 1614.735199]  [<ffffffff8160d19e>] icmp_socket_deliver+0xce/0x230
[ 1614.735203]  [<ffffffff8160d116>] ? icmp_socket_deliver+0x46/0x230
[ 1614.735208]  [<ffffffff8160d464>] icmp_unreach+0xe4/0x2c0
[ 1614.735213]  [<ffffffff8160e520>] icmp_rcv+0x350/0x4a0
[ 1614.735217]  [<ffffffff815d3285>] ip_local_deliver_finish+0x135/0x4e0
[ 1614.735221]  [<ffffffff815d319c>] ? ip_local_deliver_finish+0x4c/0x4e0
[ 1614.735225]  [<ffffffff815d3ffa>] ip_local_deliver+0x4a/0x90
[ 1614.735229]  [<ffffffff815d37b7>] ip_rcv_finish+0x187/0x730
[ 1614.735233]  [<ffffffff815d425d>] ip_rcv+0x21d/0x300
[ 1614.735237]  [<ffffffff81592a1b>] __netif_receive_skb+0x46b/0xd00
[ 1614.735241]  [<ffffffff81592801>] ? __netif_receive_skb+0x251/0xd00
[ 1614.735245]  [<ffffffff81593368>] process_backlog+0xb8/0x180
[ 1614.735249]  [<ffffffff81593cf9>] net_rx_action+0x159/0x330
[ 1614.735257]  [<ffffffff810491f0>] __do_softirq+0xd0/0x3e0
[ 1614.735264]  [<ffffffff8109ed24>] ? tick_program_event+0x24/0x30
[ 1614.735270]  [<ffffffff8175419c>] call_softirq+0x1c/0x30
[ 1614.735278]  [<ffffffff8100425d>] do_softirq+0x8d/0xc0
[ 1614.735282]  [<ffffffff8104983e>] irq_exit+0xae/0xe0
[ 1614.735287]  [<ffffffff8175494e>] smp_apic_timer_interrupt+0x6e/0x99
[ 1614.735291]  [<ffffffff81753a1c>] apic_timer_interrupt+0x6c/0x80
[ 1614.735293]  <EOI>  [<ffffffff810a14ad>] ? trace_hardirqs_off+0xd/0x10
[ 1614.735306]  [<ffffffff81336f85>] ? intel_idle+0xf5/0x150
[ 1614.735310]  [<ffffffff81336f7e>] ? intel_idle+0xee/0x150
[ 1614.735317]  [<ffffffff814e6ea9>] cpuidle_enter+0x19/0x20
[ 1614.735321]  [<ffffffff814e7538>] cpuidle_idle_call+0xa8/0x630
[ 1614.735327]  [<ffffffff8100c1ba>] cpu_idle+0x8a/0xe0
[ 1614.735333]  [<ffffffff8173762e>] start_secondary+0x220/0x222
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Avoid to use synchronize_rcu in l2tp_tunnel_free because context may be
atomic.
Signed-off-by: NDmitry Kozlov <xeb@mail.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Change l2tp_xmit_skb() to return NET_XMIT_DROP in case skb is dropped.

Use kfree_skb() instead dev_kfree_skb() for drop_monitor pleasure.

Support tx_dropped counter for l2tp_eth
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: James Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use more current logging styles.

Add pr_fmt to prefix output appropriately.
Convert printks to pr_<level>.
Convert PRINTK macros to new l2tp_<level> macros.
Neaten some <foo>_refcount debugging macros.
Use print_hex_dump_bytes instead of hand-coded loops.
Coalesce formats and align arguments.

Some KERN_DEBUG output is not now emitted unless
dynamic_debugging is enabled.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If enabled, L2TP data packets have sequence numbers which a receiver
can use to drop out of sequence frames or try to reorder them. The
first frame has sequence number 0, but the L2TP code currently expects
it to be 1. This results in the first data frame being handled as out
of sequence.

This one-line patch fixes the problem.
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When L2TP data packet reordering is enabled, packets are held in a
queue while waiting for out-of-sequence packets. If a packet gets
lost, packets will be held until the reorder timeout expires, when we
are supposed to then advance to the sequence number of the next packet
but we don't currently do so. As a result, the data channel is stuck
because we are waiting for a packet that will never arrive - all
packets age out and none are passed.

The fix is to add a flag to the session context, which is set when the
reorder timeout expires and tells the receive code to reset the next
expected sequence number to that of the next packet in the queue.

Tested in a production L2TP network with Starent and Nortel L2TP gear.
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The netlink API lets users create unmanaged L2TPv3 tunnels using
iproute2. Until now, a request to create an unmanaged L2TPv3 IP
encapsulation tunnel over IPv6 would be rejected with
EPROTONOSUPPORT. Now that l2tp_ip6 implements sockets for L2TP IP
encapsulation over IPv6, we can add support for that tunnel type.
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds support for unmanaged L2TPv3 tunnels over IPv6 using
the netlink API. We already support unmanaged L2TPv3 tunnels over
IPv4. A patch to iproute2 to make use of this feature will be
submitted separately.
Signed-off-by: NChris Elston <celston@katalix.com>
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

L2TP uses 64-bit counters but since these are not updated atomically,
we need to make them safe for smp. This patch addresses that.
Signed-off-by: NJames Chapman <jchapman@katalix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that encap_rcv() works on IPv6 UDP sockets, wire L2TP up to IPv6.
Support has been tested with and without hardware offloading.  This
version fixes the L2TP over localhost issue with incorrect checksums
being reported.
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Most machines dont use UDP encapsulation (L2TP)

Adds a static_key so that udp_queue_rcv_skb() doesnt have to perform a
test if L2TP never setup the encap_rcv on a socket.

Idea of this patch came after Simon Horman proposal to add a hook on TCP
as well.

If static_key is not yet enabled, the fast path does a single JMP .

When static_key is enabled, JMP destination is patched to reach the real
encap_type/encap_rcv logic, possibly adding cache misses.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: dev@openvswitch.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When using l2tp over ipsec, the tunnel will hang when rekeying
occurs. Reason is that the transformer bundle attached to the dst entry
is now in STATE_DEAD and thus xfrm_output_one() drops all packets
(XfrmOutStateExpired increases).

Fix this by calling __sk_dst_check (which drops the stale dst
if xfrm dst->check callback finds that the bundle is no longer valid).

Cc: James Chapman <jchapman@katalix.com>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

pskb_may_pull() can change skb->data, so we have to load ptr/optr at the
right place.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Misha Labjuk reported panics occurring in l2tp_recv_dequeue()

If we release reorder_q.lock, we must not keep a dangling pointer (tmp),
since another thread could manipulate reorder_q.

Instead we must restart the scan at beginning of list.
Reported-by: NMisha Labjuk <spiked.yar@gmail.com>
Tested-by: NMisha Labjuk <spiked.yar@gmail.com>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

l2tp_xmit_skb() can leak one skb if skb_cow_head() returns an error.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>
Signed-off-by: NArun Sharma <asharma@fb.com>
Reviewed-by: NEric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

While trying to remove useless synchronize_rcu() calls, I found l2tp is
indeed incorrectly using two of such calls, but also bumps tunnel
refcount after list insertion.

tunnel refcount must be incremented before being made publically visible
by rcu readers.

This fix can be applied to 2.6.35+ and might need a backport for older
kernels, since things were shuffled in commit fd558d18
(l2tp: Split pppol2tp patch into separate l2tp and ppp parts)
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
CC: James Chapman <jchapman@katalix.com>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>