Since l2cap_send_ack can trigger extra actions like sending iframes,
don't call it.  Just send an RR or RNR frame if an ack needs sending.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

Different states have different actions for retransmit and monitor
timeouts, so remove the logic for those actions from the timer handlers.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

The ERTM specification requires the retransmit timer to be cancelled
when the monitor timer is set.  The retransmit timer cannot be set
again while the monitor timer is pending.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

struct l2cap_ctrl is now used, and the sframe is now sent directly
rather than depending on a separate call.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

REJ frames are sent by the remote device to request that all frames
after a given sequence number be retransmitted.  These are also an
implicit indication that the remote device is not in a busy state and
can receive new iframes.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

When a remote device sends an SREJ, retransmit the frame with the
corresponding sequence number (subject to special cases with poll and
final flags).  An SREJ is also an implicit indication the the remote
device is not in a busy state.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

As retransmitted packets arrive, attempt to reassemble SDUs.  If all
requested retransmissions have been received, acknowledge them and
transition back to the RECV state.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

The ERTM specification lays out three scenarios for sending SREJ
frames to request retransmission of specific frames.  l2cap_send_srej
requests all frames up to a given txseq that are not already queued
for reassembly.  l2cap_send_srej_tail only requests the most recent
missing frame.  l2cap_send_srej_list resends SREJ frames for data that
was requested for resend but never received.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This adds l2cap_ertm_resend to retransmit frames based on the sequence
numbers in chan->retrans_list.  If the retransmit limit is reached for
any individual frame is reached, the connection is dropped.  skbs that
are cloned already are copied to avoid modifying shared data (this is
uncommon).  To retransmit all frames, l2cap_retransmit_all now builds
a list of all unacked sequence numbers and then calls
l2cap_ertm_resend.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This adds a top-level state machine with handlers for two receive
states defined in the ERTM spec, RECV and SREJ_SENT.  The reqseq value
of the incoming frame is also validated at the top level and a
disconnection is forced if it is invalid.  The actions for the RECV
and SREJ_SENT states are implemented according to the state tables in
the ERTM specification.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This action now exactly matches what is defined in the ERTM
specification, including clearing the remote busy flag and setting the
retransmit timer rather than retransmitting frames directly.  The spec
does not retransmit frames as part of this action, since
retransmission is only triggered by REJ, SREJ, or an RR with the final
bit set.  struct l2cap_ctrl is also used to set up header values.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This lets the transmit state machine handle local busy state changes,
since different actions are taken in the different transmit states.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

The function now encapsulates more of the logic to either immediately
send an ack if the transmit window is over 75% full, or wait for the
ack timer to expire if the transmit window is not full enough.  It is
also able to push out waiting iframes that can carry an
acknowledgement.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This deletes the receive code that had handlers for each frame type at
the top level, and then had logic to determine the receive state
within each handler.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

Streaming mode reception is fairly simple, with in-sequence frames
being reassembled as they arrive.  Out-of-sequence frames are dropped,
and also clear any partially-assembled SDUs that may exist.

The packet classifier determines if the txseq value of the incoming
packet is expected, invalid (resulting in a disconnection), invalid
(ignorable), duplicate, or having to do with an SREJ request that was
previously sent.  The rules for each classification are defined in the
ERTM specification, and consolidating these rules in one place helps
clarify the receive state machine.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

Creates a new l2cap_data_rcv function that combines previous code from
l2cap_ertm_data_rcv and l2cap_data_channel.  This reduces duplicate
code for streaming mode, and sets up a framework for the ERTM receive
state machine.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

The new implementation uses struct l2cap_ctrl to set up the sframe
fields, and also reduces duplicate acks by canceling the ack timer
whenever an RR or RNR frame is sent.  sframe PDU generation is also
split in to a separate function to separate it from the logic related
to the connection state and sframe type.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

The new implementation is aware of the new transmit state machine, and
uses struct l2cap_ctrl to compose ERTM headers.  It also has improved
error handling for allocation failures, and does not send the packet
until after all skb and channel data structures are updated.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This new implementation uses struct l2cap_ctrl to compose the
streaming mode headers.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This implements a top-level transmit state machine with handlers for
the two ERTM states defined in the specification: XMIT and WAIT_F.

The state machine accepts an event and, optionally, a list of skbs to
transmit.  In addition to data transmission, the local busy state can
be modified, acks are processed, and monitor and retransmit timeouts
are handled.  This mirrors the structure of the state tables in the
spec.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This is to allow for ERTM state machine replacement in the patches
that follow.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>

This fixes a regression from commit
2ead70b8 that is present in all
kernels starting at v3.0.

When L2CAP information was moved to struct l2cap_chan, a check was
added to l2cap_chan_del to avoid certain cleanup operations when ERTM
or streaming mode had not yet been initialized.  The logic in the
check did not take in to account that chan->conf_state is set to 0 in
l2cap_chan_ready, so l2cap_chan_del failed to cancel timers and leaked
memory any time the ERTM queues or lists were not empty.

This change makes sure that l2cap_chan_del only returns early if
ERTM initialization was not performed.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

If the ERTM SREJ list is properly allocated but the retransmit list
allocation fails, the SREJ list must be freed before returning from
l2cap_ertm_init.  l2cap_chan_del will not clean up the SREJ list
if l2cap_ertm_init returns a failure code.
Signed-off-by: NMat Martineau <mathewm@codeaurora.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Follow net subsystem rules.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Follow net subsystem rules.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Follow the net subsystem rules.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Follow the net subsystem rules.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Follow the net subsystem rules.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Follow the net subsystem rules.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

Follow the coding style of the net subsystem.
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

This reverts the tty layer change to use per-tty locking, because it's
not correct yet, and fixing it will require some more deep surgery.

The main revert is d29f3ef3 ("tty_lock: Localise the lock"), but
there are several smaller commits that built upon it, they also get
reverted here. The list of reverted commits is:

  fde86d31 - tty: add lockdep annotations
  8f6576ad - tty: fix ldisc lock inversion trace
  d3ca8b64 - pty: Fix lock inversion
  b1d679af - tty: drop the pty lock during hangup
  abcefe5f - tty/amiserial: Add missing argument for tty_unlock()
  fd11b42e - cris: fix missing tty arg in wait_event_interruptible_tty call
  d29f3ef3 - tty_lock: Localise the lock

The revert had a trivial conflict in the 68360serial.c staging driver
that got removed in the meantime.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

While testing how linux behaves on SYNFLOOD attack on multiqueue device
(ixgbe), I found that SYNACK messages were dropped at Qdisc level
because we send them all on a single queue.

Obvious choice is to reflect incoming SYN packet @queue_mapping to
SYNACK packet.

Under stress, my machine could only send 25.000 SYNACK per second (for
200.000 incoming SYN per second). NIC : ixgbe with 16 rx/tx queues.

After patch, not a single SYNACK is dropped.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Hans Schillstrom <hans.schillstrom@ericsson.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Another problem on SYNFLOOD/DDOS attack is the inetpeer cache getting
larger and larger, using lots of memory and cpu time.

tcp_v4_send_synack()
->inet_csk_route_req()
 ->ip_route_output_flow()
  ->rt_set_nexthop()
   ->rt_init_metrics()
    ->inet_getpeer( create = true)

This is a side effect of commit a4daad6b (net: Pre-COW metrics for
TCP) added in 2.6.39

Possible solution :

Instruct inet_csk_route_req() to remove FLOWI_FLAG_PRECOW_METRICS

Before patch :

# grep peer /proc/slabinfo
inet_peer_cache   4175430 4175430    192   42    2 : tunables    0    0    0 : slabdata  99415  99415      0

Samples: 41K of event 'cycles', Event count (approx.): 30716565122
+  20,24%      ksoftirqd/0  [kernel.kallsyms]           [k] inet_getpeer
+   8,19%      ksoftirqd/0  [kernel.kallsyms]           [k] peer_avl_rebalance.isra.1
+   4,81%      ksoftirqd/0  [kernel.kallsyms]           [k] sha_transform
+   3,64%      ksoftirqd/0  [kernel.kallsyms]           [k] fib_table_lookup
+   2,36%      ksoftirqd/0  [ixgbe]                     [k] ixgbe_poll
+   2,16%      ksoftirqd/0  [kernel.kallsyms]           [k] __ip_route_output_key
+   2,11%      ksoftirqd/0  [kernel.kallsyms]           [k] kernel_map_pages
+   2,11%      ksoftirqd/0  [kernel.kallsyms]           [k] ip_route_input_common
+   2,01%      ksoftirqd/0  [kernel.kallsyms]           [k] __inet_lookup_established
+   1,83%      ksoftirqd/0  [kernel.kallsyms]           [k] md5_transform
+   1,75%      ksoftirqd/0  [kernel.kallsyms]           [k] check_leaf.isra.9
+   1,49%      ksoftirqd/0  [kernel.kallsyms]           [k] ipt_do_table
+   1,46%      ksoftirqd/0  [kernel.kallsyms]           [k] hrtimer_interrupt
+   1,45%      ksoftirqd/0  [kernel.kallsyms]           [k] kmem_cache_alloc
+   1,29%      ksoftirqd/0  [kernel.kallsyms]           [k] inet_csk_search_req
+   1,29%      ksoftirqd/0  [kernel.kallsyms]           [k] __netif_receive_skb
+   1,16%      ksoftirqd/0  [kernel.kallsyms]           [k] copy_user_generic_string
+   1,15%      ksoftirqd/0  [kernel.kallsyms]           [k] kmem_cache_free
+   1,02%      ksoftirqd/0  [kernel.kallsyms]           [k] tcp_make_synack
+   0,93%      ksoftirqd/0  [kernel.kallsyms]           [k] _raw_spin_lock_bh
+   0,87%      ksoftirqd/0  [kernel.kallsyms]           [k] __call_rcu
+   0,84%      ksoftirqd/0  [kernel.kallsyms]           [k] rt_garbage_collect
+   0,84%      ksoftirqd/0  [kernel.kallsyms]           [k] fib_rules_lookup
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Hans Schillstrom <hans.schillstrom@ericsson.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sockfd_lookup() is declared in linux/net.h, which is pulled by
linux/skbuff.h (and needed for a lot of other stuff in sch_atm.c
anyway).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Move the rq_flavor into struct svc_cred, and use it in setclientid and
exchange_id comparisons as well.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Instead of keeping the principal name associated with a request in a
structure that's private to auth_gss and using an accessor function,
move it to svc_cred.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

There's little point in waiting until after we allocate all of the pages
to see if we're going to overrun the array. In the event that this
calculation is really off we could end up scribbling over a bunch of
memory and make it tougher to debug.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

The idea is to separate service destruction and per-net operations,
because these are two different things and the mix looks ugly.

Notes:

1) For NFS server this patch looks ugly (sorry for that). But these
place will be rewritten soon during NFSd containerization.

2) LockD per-net counter increase int lockd_up() was moved prior to
make_socks() to make lockd_down_net() call safe in case of error.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

This new routine is responsible for service registration in a specified
network context.

The idea is to separate service creation from per-net operations.

Note also: since registering service with svc_bind() can fail, the
service will be destroyed and during destruction it will try to
unregister itself from rpcbind. In this case unregistration has to be
skipped.
Signed-off-by: NStanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>