enqueue_event is added as a member of sctp_stream_interleave, used to
enqueue either data, idata or notification events into user socket rx
queue.

It replaces sctp_ulpq_tail_event used in the other places with
enqueue_event.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ulpevent_data is added as a member of sctp_stream_interleave, used to
do the most process in ulpq, including to convert data or idata chunk
to event, reasm them in reasm queue and put them in lobby queue in
right order, and deliver them up to user sk rx queue.

This procedure is described in section 2.2.3 of RFC8260.

It adds most functions for idata here to do the similar process as
the old functions for data. But since the details are very different
between them, the old functions can not be reused for idata.

event->ssn and event->ppid settings are moved to ulpevent_data from
sctp_ulpevent_make_rcvmsg, so that sctp_ulpevent_make_rcvmsg could
work for both data and idata.

Note that mid is added in sctp_ulpevent for idata, __packed has to
be used for defining sctp_ulpevent, or it would exceeds the skb cb
that saves a sctp_ulpevent variable for ulp layer process.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These warnings were found by running 'make C=2 M=net/sctp/'.
They are there since very beginning.

Note after this patch, there still one warning left in
sctp_outq_flush():
  sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM)

Since it has been moved to sctp_stream_outq_migrate on net-next,
to avoid the extra job when merging net-next to net, I will post
the fix for it after the merging is done.
Reported-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These warnings were found by running 'make C=2 M=net/sctp/'.

Commit d4d6fb57 ("sctp: Try not to change a_rwnd when faking a
SACK from SHUTDOWN.") expected to use the peers old rwnd and add
our flight size to the a_rwnd. But with the wrong Endian, it may
not work as well as expected.

So fix it by converting to the right value.

Fixes: d4d6fb57 ("sctp: Try not to change a_rwnd when faking a SACK from SHUTDOWN.")
Reported-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-sctp@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces the hooks necessary to do stream scheduling, as
per RFC Draft ndata.  It also introduces the first scheduler, which is
what we do today but now factored out: first come first served (FCFS).

With stream scheduling now we have to track which chunk was enqueued on
which stream and be able to select another other than the in front of
the main outqueue. So we introduce a list on sctp_stream_out_ext
structure for this purpose.

We reuse sctp_chunk->transmitted_list space for the list above, as the
chunk cannot belong to the two lists at the same time. By using the
union in there, we can have distinct names for these moments.

sctp_sched_ops are the operations expected to be implemented by each
scheduler. The dequeueing is a bit particular to this implementation but
it is to match how we dequeue packets today. We first dequeue and then
check if it fits the packet and if not, we requeue it at head. Thus why
we don't have a peek operation but have dequeue_done instead, which is
called once the chunk can be safely considered as transmitted.

The check removed from sctp_outq_flush is now performed by
sctp_stream_outq_migrate, which is only called during assoc setup.
(sctp_sendmsg() also checks for it)

The only operation that is foreseen but not yet added here is a way to
signalize that a new packet is starting or that the packet is done, for
round robin scheduler per packet, but is intentionally left to the
patch that actually implements it.

Support for I-DATA chunks, also described in this RFC, with user message
interleaving is straightforward as it just requires the schedulers to
probe for the feature and ignore datamsg boundaries when dequeueing.

See-also: https://tools.ietf.org/html/draft-ietf-tsvwg-sctp-ndata-13Tested-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_disposition_t, and
replace with enum sctp_disposition in the places where it's
using this typedef.

It's also to fix the indent for many functions' defination.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_sm_table_entry_t, and
replace with struct sctp_sm_table_entry in the places where it's
using this typedef.

It is also to fix some indents.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_cmd_seq_t, and
replace with struct sctp_cmd_seq in the places where it's
using this typedef.

Note that it doesn't fix many indents although it should,
as sctp_disposition_t's removal would mess them up again.
So better to fix them when removing sctp_disposition_t in
the later patch.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_cmd_t, and
replace with enum sctp_cmd in the places where it's
using this typedef.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_sender_hb_info_t, and
replace with struct sctp_sender_hb_info in the places where it's
using this typedef.

It is also to use sizeof(variable) instead of sizeof(type).
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_subtype_t, and
replace with union sctp_subtype in the places where it's
using this typedef.

Note that it doesn't fix many indents although it should,
as sctp_disposition_t's removal would mess them up again.
So better to fix them when removing sctp_disposition_t in
later patch.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_event_t, and
replace with enum sctp_event in the places where it's
using this typedef.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_event_timeout_t, and
replace with enum sctp_event_timeout in the places where it's
using this typedef.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_state_t, and
replace with enum sctp_state in the places where it's
using this typedef.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_errhdr_t, and replace
with struct sctp_errhdr in the places where it's using this
typedef.

It is also to use sizeof(variable) instead of sizeof(type).
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_init_chunk_t, and replace
with struct sctp_init_chunk in the places where it's using this
typedef.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to remove the typedef sctp_chunkhdr_t, and replace
with struct sctp_chunkhdr in the places where it's using this
typedef.

It is also to fix some indents and use sizeof(variable) instead
of sizeof(type)., especially in sctp_new.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It's a bad thing not to handle errors when updating asoc. The memory
allocation failure in any of the functions called in sctp_assoc_update()
would cause sctp to work unexpectedly.

This patch is to fix it by aborting the asoc and reporting the error when
any of these functions fails.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

local_cork is used to decide if it should uncork asoc outq after processing
some cmds, and it is set when replying or sending msgs. local_cork should
always have the same value with current asoc q->cork in some way.

The thing is when changing to a new asoc by cmd SET_ASOC, local_cork may
not be consistent with the current asoc any more. The cmd seqs can be:

  SCTP_CMD_UPDATE_ASSOC (asoc)
  SCTP_CMD_REPLY (asoc)
  SCTP_CMD_SET_ASOC (new_asoc)
  SCTP_CMD_DELETE_TCB (new_asoc)
  SCTP_CMD_SET_ASOC (asoc)
  SCTP_CMD_REPLY (asoc)

The 1st REPLY makes OLD asoc q->cork and local_cork both are 1, and the cmd
DELETE_TCB clears NEW asoc q->cork and local_cork. After asoc goes back to
OLD asoc, q->cork is still 1 while local_cork is 0. The 2nd REPLY will not
set local_cork because q->cork is already set and it can't be uncorked and
sent out because of this.

To keep local_cork consistent with the current asoc q->cork, this patch is
to uncork the old asoc if local_cork is set before changing to the new one.

Note that the above cmd seqs will be used in the next patch when updating
asoc and handling errors in it.
Suggested-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to flush out queue when assoc state falls into
SHUTDOWN_PENDING if there are still chunks in it, so that the
data can be sent out as soon as possible before sending SHUTDOWN
chunk.

When sctp supports MSG_MORE flag in next patch, this improvement
can also solve the problem that the chunks with MSG_MORE flag
may be stuck in queue when closing an assoc.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add new transport flag to allow sockets to confirm neighbour.
When same struct dst_entry can be used for many different
neighbours we can not use it for pending confirmations.
The flag is propagated from transport to every packet.
It is reset when cached dst is reset.
Reported-by: NYueHaibing <yuehaibing@huawei.com>
Fixes: 5110effe ("net: Do delayed neigh confirmation.")
Fixes: f2bb4bed ("ipv4: Cache output routes in fib_info nexthops.")
Signed-off-by: NJulian Anastasov <ja@ssi.bg>
Acked-by: NEric Dumazet <edumazet@google.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to add a per transport timer based on sctp timer frame
for stream reconf chunk retransmission. It would start after sending
a reconf request chunk, and stop after receiving the response chunk.

If the timer expires, besides retransmitting the reconf request chunk,
it would also do the same thing with data RTO timer. like to increase
the appropriate error counts, and perform threshold management, possibly
destroying the asoc if sctp retransmission thresholds are exceeded, just
as section 5.1.1 describes.

This patch is also to add asoc strreset_chunk, it is used to save the
reconf request chunk, so that it can be retransmitted, and to check if
the response is really for this request by comparing the information
inside with the response chunk as well.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sctp_outq_flush return value is meaningless now, this patch is
to make sctp_outq_flush return void, as well as sctp_outq_fail
and sctp_outq_uncork.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Once a chunk is enqueued successfully, sctp queues can take care of it.
Even if it is failed to transmit (like because of nomem), it should be
put into retransmit queue.

If sctp report this error to users, it confuses them, they may resend
that msg, but actually in kernel sctp stack is in charge of retransmit
it already.

Besides, this error probably is not from the failure of transmitting
current msg, but transmitting or retransmitting another msg's chunks,
as sctp_outq_flush just tries to send out all transports' chunks.

This patch is to make sctp_cmd_send_msg return avoid, and not return the
transmit err back to sctp_sendmsg

Fixes: 8b570dc9 ("sctp: only drop the reference on the datamsg after sending a msg")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now sctp doesn't change socket state upon shutdown reception. It changes
just the assoc state, even though it's a TCP-style socket.

For some cases, if we really need to check sk->sk_state, it's necessary to
fix this issue, at least when we use ss or netstat to dump, we can get a
more exact information.

As an improvement, we will change sk->sk_state when we change asoc->state
to SHUTDOWN_RECEIVED, and also do it in sctp_shutdown to keep consistent
with sctp_close.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Dave Miller pointed out that fb586f25 ("sctp: delay calls to
sk_data_ready() as much as possible") may insert latency specially if
the receiving application is running on another CPU and that it would be
better if we signalled as early as possible.

This patch thus basically inverts the logic on fb586f25 and signals
it as early as possible, similar to what we had before.

Fixes: fb586f25 ("sctp: delay calls to sk_data_ready() as much as possible")
Reported-by: NDave Miller <davem@davemloft.net>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently processing of multiple chunks in a single SCTP packet leads to
multiple calls to sk_data_ready, causing multiple wake up signals which
are costy and doesn't make it wake up any faster.

With this patch it will note that the wake up is pending and will do it
before leaving the state machine interpreter, latest place possible to
do it realiably and cleanly.

Note that sk_data_ready events are not dependent on asocs, unlike waking
up writers.

v2: series re-checked
v3: use local vars to cleanup the code, suggested by Jakub Sitnicki
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently on high rate SCTP streams the heartbeat timer refresh can
consume quite a lot of resources as timer updates are costly and it
contains a random factor, which a) is also costly and b) invalidates
mod_timer() optimization for not editing a timer to the same value.
It may even cause the timer to be slightly advanced, for no good reason.

As suggested by David Laight this patch now removes this timer update
from hot path by leaving the timer on and re-evaluating upon its
expiration if the heartbeat is still needed or not, similarly to what is
done for TCP. If it's not needed anymore the timer is re-scheduled to
the new timeout, considering the time already elapsed.

For this, we now record the last tx timestamp per transport, updated in
the same spots as hb timer was restarted on tx. Also split up
sctp_transport_reset_timers into sctp_transport_reset_t3_rtx and
sctp_transport_reset_hb_timer, so we can re-arm T3 without re-arming the
heartbeat one.

On loopback with MTU of 65535 and data chunks with 1636, so that we
have a considerable amount of chunks without stressing system calls,
netperf -t SCTP_STREAM -l 30, perf looked like this before:

Samples: 103K of event 'cpu-clock', Event count (approx.): 25833000000
  Overhead  Command  Shared Object      Symbol
+    6,15%  netperf  [kernel.vmlinux]   [k] copy_user_enhanced_fast_string
-    5,43%  netperf  [kernel.vmlinux]   [k] _raw_write_unlock_irqrestore
   - _raw_write_unlock_irqrestore
      - 96,54% _raw_spin_unlock_irqrestore
         - 36,14% mod_timer
            + 97,24% sctp_transport_reset_timers
            + 2,76% sctp_do_sm
         + 33,65% __wake_up_sync_key
         + 28,77% sctp_ulpq_tail_event
         + 1,40% del_timer
      - 1,84% mod_timer
         + 99,03% sctp_transport_reset_timers
         + 0,97% sctp_do_sm
      + 1,50% sctp_ulpq_tail_event

And after this patch, now with netperf -l 60:

Samples: 230K of event 'cpu-clock', Event count (approx.): 57707250000
  Overhead  Command  Shared Object      Symbol
+    5,65%  netperf  [kernel.vmlinux]   [k] memcpy_erms
+    5,59%  netperf  [kernel.vmlinux]   [k] copy_user_enhanced_fast_string
-    5,05%  netperf  [kernel.vmlinux]   [k] _raw_spin_unlock_irqrestore
   - _raw_spin_unlock_irqrestore
      + 49,89% __wake_up_sync_key
      + 45,68% sctp_ulpq_tail_event
      - 2,85% mod_timer
         + 76,51% sctp_transport_reset_t3_rtx
         + 23,49% sctp_do_sm
      + 1,55% del_timer
+    2,50%  netperf  [sctp]             [k] sctp_datamsg_from_user
+    2,26%  netperf  [sctp]             [k] sctp_sendmsg

Throughput-wise, from 6800mbps without the patch to 7050mbps with it,
~3.7%.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The SACK can be lost pretty much elsewhere, but if its allocation fail,
we know we are not sending it, so it is better to revert a_rwnd to its
previous value as this may give it a chance to issue a window update
later.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently sctp_sendmsg() triggers some calls that will allocate memory
with GFP_ATOMIC even when not necessary. In the case of
sctp_packet_transmit it will allocate a linear skb that will be used to
construct the packet and this may cause sends to fail due to ENOMEM more
often than anticipated specially with big MTUs.

This patch thus allows it to inherit gfp flags from upper calls so that
it can use GFP_KERNEL if it was triggered by a sctp_sendmsg call or
similar. All others, like retransmits or flushes started from BH, are
still allocated using GFP_ATOMIC.

In netperf tests this didn't result in any performance drawbacks when
memory is not too fragmented and made it trigger ENOMEM way less often.
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After we use refcnt to check if transport is alive, the dead can be
removed from sctp_transport.

The traversal of transport_addr_list in procfs dump is using
list_for_each_entry_rcu, no need to check if it has been freed.

sctp_generate_t3_rtx_event and sctp_generate_heartbeat_event is
protected by sock lock, it's not necessary to check dead, either.
also, the timers are cancelled when sctp_transport_free() is
called, that it doesn't wait for refcnt to reach 0 to cancel them.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Dmitry Vyukov reported a use-after-free in the code expanded by the
macro debug_post_sfx, which is caused by the use of the asoc pointer
after it was freed within sctp_side_effect() scope.

This patch fixes it by allowing sctp_side_effect to clear that asoc
pointer when the TCB is freed.

As Vlad explained, we also have to cover the SCTP_DISPOSITION_ABORT case
because it will trigger DELETE_TCB too on that same loop.

Also, there were places issuing SCTP_CMD_INIT_FAILED and ASSOC_FAILED
but returning SCTP_DISPOSITION_CONSUME, which would fool the scheme
above. Fix it by returning SCTP_DISPOSITION_ABORT instead.

The macro is already prepared to handle such NULL pointer.
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

transport hashtable will replace the association hashtable,
so association hashtable is not used in sctp any more, so
drop the codes about that.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As we all know, the value of pf_retrans >= max_retrans_path can
disable pf state. The variables of pf_retrans and max_retrans_path
can be changed by the userspace application.

Sometimes the user expects to disable pf state while the 2
variables are changed to enable pf state. So it is necessary to
introduce a new variable to disable pf state.

According to the suggestions from Vlad Yasevich, extra1 and extra2
are removed. The initialization of pf_enable is added.
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NZhu Yanjun <zyjzyj2000@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A case can occur when sctp_accept() is called by the user during
a heartbeat timeout event after the 4-way handshake.  Since
sctp_assoc_migrate() changes both assoc->base.sk and assoc->ep, the
bh_sock_lock in sctp_generate_heartbeat_event() will be taken with
the listening socket but released with the new association socket.
The result is a deadlock on any future attempts to take the listening
socket lock.

Note that this race can occur with other SCTP timeouts that take
the bh_lock_sock() in the event sctp_accept() is called.

 BUG: soft lockup - CPU#9 stuck for 67s! [swapper:0]
 ...
 RIP: 0010:[<ffffffff8152d48e>]  [<ffffffff8152d48e>] _spin_lock+0x1e/0x30
 RSP: 0018:ffff880028323b20  EFLAGS: 00000206
 RAX: 0000000000000002 RBX: ffff880028323b20 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: ffff880028323be0 RDI: ffff8804632c4b48
 RBP: ffffffff8100bb93 R08: 0000000000000000 R09: 0000000000000000
 R10: ffff880610662280 R11: 0000000000000100 R12: ffff880028323aa0
 R13: ffff8804383c3880 R14: ffff880028323a90 R15: ffffffff81534225
 FS:  0000000000000000(0000) GS:ffff880028320000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
 CR2: 00000000006df528 CR3: 0000000001a85000 CR4: 00000000000006e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
 Process swapper (pid: 0, threadinfo ffff880616b70000, task ffff880616b6cab0)
 Stack:
 ffff880028323c40 ffffffffa01c2582 ffff880614cfb020 0000000000000000
 <d> 0100000000000000 00000014383a6c44 ffff8804383c3880 ffff880614e93c00
 <d> ffff880614e93c00 0000000000000000 ffff8804632c4b00 ffff8804383c38b8
 Call Trace:
 <IRQ>
 [<ffffffffa01c2582>] ? sctp_rcv+0x492/0xa10 [sctp]
 [<ffffffff8148c559>] ? nf_iterate+0x69/0xb0
 [<ffffffff814974a0>] ? ip_local_deliver_finish+0x0/0x2d0
 [<ffffffff8148c716>] ? nf_hook_slow+0x76/0x120
 [<ffffffff814974a0>] ? ip_local_deliver_finish+0x0/0x2d0
 [<ffffffff8149757d>] ? ip_local_deliver_finish+0xdd/0x2d0
 [<ffffffff81497808>] ? ip_local_deliver+0x98/0xa0
 [<ffffffff81496ccd>] ? ip_rcv_finish+0x12d/0x440
 [<ffffffff81497255>] ? ip_rcv+0x275/0x350
 [<ffffffff8145cfeb>] ? __netif_receive_skb+0x4ab/0x750
 ...

With lockdep debugging:

 =====================================
 [ BUG: bad unlock balance detected! ]
 -------------------------------------
 CslRx/12087 is trying to release lock (slock-AF_INET) at:
 [<ffffffffa01bcae0>] sctp_generate_timeout_event+0x40/0xe0 [sctp]
 but there are no more locks to release!

 other info that might help us debug this:
 2 locks held by CslRx/12087:
 #0:  (&asoc->timers[i]){+.-...}, at: [<ffffffff8108ce1f>] run_timer_softirq+0x16f/0x3e0
 #1:  (slock-AF_INET){+.-...}, at: [<ffffffffa01bcac3>] sctp_generate_timeout_event+0x23/0xe0 [sctp]

Ensure the socket taken is also the same one that is released by
saving a copy of the socket before entering the timeout event
critical section.
Signed-off-by: NKarl Heiss <kheiss@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix indentation in sctp_generate_heartbeat_event.
Signed-off-by: NKarl Heiss <kheiss@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When removing an non-primary transport during ASCONF
processing, we end up traversing the transport list
twice: once in sctp_cmd_del_non_primary, and once in
sctp_assoc_del_peer.  We can avoid the second
search and call sctp_assoc_rm_peer() instead.
Found by code inspection during code reviews.
Signed-off-by: NVladislav Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit f8d96052 ("sctp: Enforce retransmission limit during shutdown")
fixed a problem with excessive retransmissions in the SHUTDOWN_PENDING by not
resetting the association overall_error_count.  This allowed the association
to better enforce assoc.max_retrans limit.

However, the same issue still exists when the association is in SHUTDOWN_RECEIVED
state.  In this state, HB-ACKs will continue to reset the overall_error_count
for the association would extend the lifetime of association unnecessarily.

This patch solves this by resetting the overall_error_count whenever the current
state is small then SCTP_STATE_SHUTDOWN_PENDING.  As a small side-effect, we
end up also handling SCTP_STATE_SHUTDOWN_ACK_SENT and SCTP_STATE_SHUTDOWN_SENT
states, but they are not really impacted because we disable Heartbeats in those
states.

Fixes: Commit f8d96052 ("sctp: Enforce retransmission limit during shutdown")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Don't transition to the PF state on every strike after 'Path.Max.Retrans'.
Per draft-ietf-tsvwg-sctp-failover-03 Section 5.1.6:

   Additional (PMR - PFMR) consecutive timeouts on a PF destination
   confirm the path failure, upon which the destination transitions to the
   Inactive state.  As described in [RFC4960], the sender (i) SHOULD notify
   ULP about this state transition, and (ii) transmit heartbeats to the
   Inactive destination at a lower frequency as described in Section 8.3 of
   [RFC4960].

This also prevents sending SCTP_ADDR_UNREACHABLE to the user as the state
bounces between SCTP_INACTIVE and SCTP_PF for each subsequent strike.
Signed-off-by: NKarl Heiss <kheiss@gmail.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>