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>

With the stream schedulers, sctp_stream_out will become too big to be
allocated by kmalloc and as we need to allocate with BH disabled, we
cannot use __vmalloc in sctp_stream_init().

This patch moves out the stats from sctp_stream_out to
sctp_stream_out_ext, which will be allocated only when the application
tries to sendmsg something on it.

Just the introduction of sctp_stream_out_ext would already fix the issue
described above by splitting the allocation in two. Moving the stats
to it also reduces the pressure on the allocator as we will ask for less
memory atomically when creating the socket and we will use GFP_KERNEL
later.

Then, for stream schedulers, we will just use sctp_stream_out_ext.
Tested-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_xmit_t, and
replace with enum sctp_xmit 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_retransmit_reason_t, and
replace with enum sctp_retransmit_reason 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_sack_variable_t, and
replace with union sctp_sack_variable in the places where it's
using this typedef.

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

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: NElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: NHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid Windsor <dwindsor@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As Marcelo's suggestion, stream is a fixed size member of asoc and would
not grow with more streams. To avoid an allocation for it, this patch is
to define it as an object instead of pointer and update the places using
it, also create sctp_stream_update() called in sctp_assoc_update() to
migrate the stream info from one stream to another.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Before when implementing sctp prsctp, SCTP_PR_STREAM_STATUS wasn't
added, as it needs to save abandoned_(un)sent for every stream.

After sctp stream reconf is added in sctp, assoc has structure
sctp_stream_out to save per stream info.

This patch is to add SCTP_PR_STREAM_STATUS by putting the prsctp
per stream statistics into sctp_stream_out.

v1->v2:
  fix an indent issue.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since sctp reconf was added in sctp, the real cnt of in/out stream
have not been c.sinit_max_instreams and c.sinit_num_ostreams any
more.

This patch is to replace them with stream->in/outcnt.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is to fix the issue that sctp_prsctp_prune_sent forgot
to update q->out_qlen when removing a chunk from unsent queue.

Fixes: 8dbdf1f5 ("sctp: implement prsctp PRIO policy")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@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 implement sender-side procedures for the Outgoing
and Incoming SSN Reset Request Parameter described in rfc6525 section
5.1.2 and 5.1.3.

It is also add sockopt SCTP_RESET_STREAMS in rfc6525 section 6.3.2
for users.

Note that the new asoc member strreset_outstanding is to make sure
only one reconf request chunk on the fly as rfc6525 section 5.1.1
demands.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Trivial fix to spelling mistake in WARN_ONCE message
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now sctp uses chunk->resent to record if a chunk is retransmitted, for
RTT measurements with retransmitted DATA chunks. chunk->sent_count was
introduced to record how many times one chunk has been sent for prsctp
RTX policy before. We actually can know if one chunk is retransmitted
by checking chunk->sent_count is greater than 1.

This patch is to remove resent from sctp_chunk and reuse sent_count
to avoid retransmitted chunks for RTT measurements.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now before using prsctp polices, sctp uses asoc->prsctp_enable to
check if prsctp is enabled. However asoc->prsctp_enable is set only
means local host support prsctp, sctp should not abandon packet if
peer host doesn't enable prsctp.

So this patch is to use asoc->peer.prsctp_capable to check if prsctp
is enabled on both side, instead of asoc->prsctp_enable, as asoc's
peer.prsctp_capable is set only when local and peer both enable prsctp.

Fixes: a6c2f792 ("sctp: implement prsctp TTL policy")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now sctp uses chunk->prsctp_param to save the prsctp param for all the
prsctp polices, we didn't need to introduce prsctp_param to sctp_chunk.
We can just use chunk->sinfo.sinfo_timetolive for RTX and BUF polices,
and reuse msg->expires_at for TTL policy, as the prsctp polices and old
expires policy are mutual exclusive.

This patch is to remove prsctp_param from sctp_chunk, and reuse msg's
expires_at for TTL and chunk's sinfo.sinfo_timetolive for RTX and BUF
polices.

Note that sctp can't use chunk's sinfo.sinfo_timetolive for TTL policy,
as it needs a u64 variables to save the expires_at time.

This one also fixes the "netperf-Throughput_Mbps -37.2% regression"
issue.

Fixes: a6c2f792 ("sctp: implement prsctp TTL policy")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sctp_acked() is using 32bit arithmetics on 16bits vars, via TSN_lte()
macros, which is weird and confusing.

Once the offset to ctsn is calculated, all wrapping is already handled
and thus to verify the Gap Ack blocks we can just use pure
less/big-or-equal than checks.

Also, rename gap variable to tsn_offset, so it's more meaningful, as
it doesn't point to any gap at all.

Even so, I don't think this discrepancy resulted in any practical bug.

This patch is a preparation for the next one, which will introduce
typecheck() for TSN_lte() macros and would cause a compile error here.
Suggested-by: NDavid Laight <David.Laight@ACULAB.COM>
Reported-by: NDavid Laight <David.Laight@ACULAB.COM>
Signed-off-by: NMarcelo Ricardo Leitner <marcelo.leitner@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>

Every time when sctp calls sctp_outq_flush, it sends out the chunks of
control queue, retransmit queue and data queue. Even if some trunks are
failed to transmit, it still has to flush all the transports, as it's
the only chance to clean that transmit_list.

So the latest transmit error here should be returned back. This transmit
error is an internal error of sctp stack.

I checked all the places where it uses the transmit error (the return
value of sctp_outq_flush), most of them are actually just save it to
sk_err.

Except for sctp_assoc/endpoint_bh_rcv, they will drop the chunk if
it's failed to send a REPLY, which is actually incorrect, as we can't
be sure the error that sctp_outq_flush returns is from sending that
REPLY.

So it's meaningless for sctp_outq_flush to return error back.

This patch is to save transmit error to sk_err in sctp_outq_flush, the
new error can update the old value. Eventually, sctp_wait_for_* would
check for it.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Last patch "sctp: do not return the transmit err back to sctp_sendmsg"
made sctp_primitive_SEND return err only when asoc state is unavailable.
In this case, chunks are not enqueued, they have no chance to be freed if
we don't take care of them later.

This Patch is actually to revert commit 1cd4d5c4 ("sctp: remove the
unused sctp_datamsg_free()"), commit 69b5777f ("sctp: hold the chunks
only after the chunk is enqueued in outq") and commit 8b570dc9 ("sctp:
only drop the reference on the datamsg after sending a msg"), to use
sctp_datamsg_free to free the chunks of current msg.

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>

Data Chunks are only sent by sctp_primitive_SEND, in which sctp checks
the asoc's state through statetable before calling sctp_outq_tail. So
there's no need to check the asoc's state again in sctp_outq_tail.

Besides, sctp_do_sm is protected by lock_sock, even if sending msg is
interrupted by timer events, the event's processes still need to acquire
lock_sock first. It means no others CMDs can be enqueue into side effect
list before CMD_SEND_MSG to change asoc->state, so it's safe to remove it.

This patch is to remove redundant asoc->state check from sctp_outq_tail.
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

prsctp PRIO policy is a policy to abandon lower priority chunks when
asoc doesn't have enough snd buffer, so that the current chunk with
higher priority can be queued successfully.

Similar to TTL/RTX policy, we will set the priority of the chunk to
prsctp_param with sinfo->sinfo_timetolive in sctp_set_prsctp_policy().
So if PRIO policy is enabled, msg->expire_at won't work.

asoc->sent_cnt_removable will record how many chunks can be checked to
remove. If priority policy is enabled, when the chunk is queued into
the out_queue, we will increase sent_cnt_removable. When the chunk is
moved to abandon_queue or dequeue and free, we will decrease
sent_cnt_removable.

In sctp_sendmsg, we will check if there is enough snd buffer for current
msg and if sent_cnt_removable is not 0. Then try to abandon chunks in
sctp_prune_prsctp when sendmsg from the retransmit/transmited queue, and
free chunks from out_queue in right order until the abandon+free size >
msg_len - sctp_wfree. For the abandon size, we have to wait until it
sends FORWARD TSN, receives the sack and the chunks are really freed.
Signed-off-by: NXin Long <lucien.xin@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>

Currently, if a chunk is scheduled to be sent through a transport that
is currently unconfirmed, it will be leaked as it is dequeued from outq
and is not re-queued nor freed.

As I'm not aware of any situation that may lead to this situation, I'm
fixing this by freeing the chunk and also logging a trace so that we can
fix the other bug if it ever happens.
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>

when A sends a data to B, then A close() and enter into SHUTDOWN_PENDING
state, if B neither claim his rwnd is 0 nor send SACK for this data, A
will keep retransmitting this data until t5 timeout, Max.Retrans times
can't work anymore, which is bad.

if B's rwnd is not 0, it should send abort after Max.Retrans times, only
when B's rwnd == 0 and A's retransmitting beyonds Max.Retrans times, A
will start t5 timer, which is also commit f8d96052 ("sctp: Enforce
retransmission limit during shutdown") means, but it lacks the condition
peer rwnd == 0.

so fix it by adding a bit (zero_window_announced) in peer to record if
the last rwnd is 0. If it was, zero_window_announced will be set. and use
this bit to decide if start t5 timer when local.state is SHUTDOWN_PENDING.

Fixes: commit f8d96052 ("sctp: Enforce retransmission limit during shutdown")
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>

When a msg is sent, sctp will hold the chunks of this msg and then try
to enqueue them. But if the chunks are not enqueued in sctp_outq_tail()
because of the invalid state, sctp_cmd_interpreter() may still return
success to sctp_sendmsg() after calling sctp_outq_flush(), these chunks
will become orphans and will leak.

So we fix them by moving sctp_chunk_hold() to sctp_outq_tail(), where we
are sure that the chunk is going to get queued.
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>

MSG_MORE and 'corking' a socket would require that the transmit of
a data chunk be delayed.
Rename the return value to be less specific.
Signed-off-by: NDavid Laight <david.laight@aculab.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The SCTP outqueue structure maintains a data chunks
that are pending transmission, the list of chunks that
are pending a retransmission and a length of data in
flight.  It also tries to keep the emtpy state so that
it can performe shutdown sequence or notify user.

The problem is that the empy state is inconsistently
tracked.  It is possible to completely drain the queue
without sending anything when using PR-SCTP.  In this
case, the empty state will not be correctly state as
report by Jamal Hadi Salim <jhs@mojatatu.com>.  This
can cause an association to be perminantly stuck in the
SHUTDOWN_PENDING state.

Additionally, SCTP is incredibly inefficient when setting
the empty state.  Even though all the data is availaible
in the outqueue structure, we ignore it and walk a list
of trasnports.

In the end, we can completely remove the extra empty
state and figure out if the queue is empty by looking
at 3 things:  length of pending data, length of in-flight
data, and exisiting of retransmit data.  All of these
are already in the strucutre.
Reported-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NVlad Yasevich <vyasevich@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Tested-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fix checkpatch errors while the space is required or prohibited
to the "=,()++..."
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NWang Weidong <wangweidong1@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Several files refer to an old address for the Free Software Foundation
in the file header comment.  Resolve by replacing the address with
the URL <http://www.gnu.org/licenses/> so that we do not have to keep
updating the header comments anytime the address changes.

CC: Vlad Yasevich <vyasevich@gmail.com>
CC: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently retransmitted DATA chunks could also be used for
RTT measurements since there are no flag to identify whether
the transmitted DATA chunk is a new one or a retransmitted one.
This problem is introduced by commit ae19c548 ("sctp: remove
'resent' bit from the chunk") which inappropriately removed the
'resent' bit completely, instead of doing this, we should set
the resent bit only for the retransmitted DATA chunks.
Signed-off-by: NXufeng Zhang <xufeng.zhang@windriver.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Function sctp_check_transmitted(transport t, ...) would iterate all of
transport->transmitted queue and looking for the highest __newly__ acked tsn.
The original algorithm would depend on the order of the assoc->transport_list
(in function sctp_outq_sack line 1215 - 1226). The result might not be the
expected due to the order of the tranport_list.

Solution: checking if the exising is smaller than the new one before assigning
Signed-off-by: NChang Xiangzhong <changxiangzhong@gmail.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With the restructuring of the lksctp.org site, we only allow bug
reports through the SCTP mailing list linux-sctp@vger.kernel.org,
not via SF, as SF is only used for web hosting and nothing more.
While at it, also remove the obvious statement that bugs will be
fixed and incooperated into the kernel.
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The SCTP mailing list address to send patches or questions
to is linux-sctp@vger.kernel.org and not
lksctp-developers@lists.sourceforge.net anymore. Therefore,
update all occurences.
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This fix has been proposed originally by Vlad Yasevich. He says:

  When SCTP makes forward progress (receives a SACK that acks new chunks,
  renegs, or answeres 0-window probes) or when HB-ACK arrives, mark
  the route as confirmed so we don't unnecessarily send NUD probes.

Having a simple SCTP client/server that exchange data chunks every 1sec,
without this patch ARP requests are sent periodically every 40-60sec.
With this fix applied, an ARP request is only done once right at the
"session" beginning. Also, when clearing the related ARP cache entry
manually during the session, a new request is correctly done. I have
only "backported" this to net-next and tested that it works, so full
credit goes to Vlad.
Signed-off-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After having reworked the debugging framework, Neil and Vlad agreed to
get rid of the leftover SCTP_DBG_TSNS code for a couple of reasons:

We can use systemtap scripts to investigate these things, we now have
pr_debug() helpers that make life easier, and if we really need anything
else besides those tools, we will be forced to come up with something
better than we have there. Therefore, get rid of this ifdef debugging
code entirely for now.
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: Neil Horman <nhorman@tuxdriver.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We should get rid of all own SCTP debug printk macros and use the ones
that the kernel offers anyway instead. This makes the code more readable
and conform to the kernel code, and offers all the features of dynamic
debbuging that pr_debug() et al has, such as only turning on/off portions
of debug messages at runtime through debugfs. The runtime cost of having
CONFIG_DYNAMIC_DEBUG enabled, but none of the debug statements printing,
is negligible [1]. If kernel debugging is completly turned off, then these
statements will also compile into "empty" functions.

While we're at it, we also need to change the Kconfig option as it /now/
only refers to the ifdef'ed code portions in outqueue.c that enable further
debugging/tracing of SCTP transaction fields. Also, since SCTP_ASSERT code
was enabled with this Kconfig option and has now been removed, we
transform those code parts into WARNs resp. where appropriate BUG_ONs so
that those bugs can be more easily detected as probably not many people
have SCTP debugging permanently turned on.

To turn on all SCTP debugging, the following steps are needed:

 # mount -t debugfs none /sys/kernel/debug
 # echo -n 'module sctp +p' > /sys/kernel/debug/dynamic_debug/control

This can be done more fine-grained on a per file, per line basis and others
as described in [2].

 [1] https://www.kernel.org/doc/ols/2009/ols2009-pages-39-46.pdf
 [2] Documentation/dynamic-debug-howto.txt
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In commit 2f94aabd
(refactor sctp_outq_teardown to insure proper re-initalization)
we modified sctp_outq_teardown to use sctp_outq_init to fully re-initalize the
outq structure.  Steve West recently asked me why I removed the q->error = 0
initalization from sctp_outq_teardown.  I did so because I was operating under
the impression that sctp_outq_init would properly initalize that value for us,
but it doesn't.  sctp_outq_init operates under the assumption that the outq
struct is all 0's (as it is when called from sctp_association_init), but using
it in __sctp_outq_teardown violates that assumption. We should do a memset in
sctp_outq_init to ensure that the entire structure is in a known state there
instead.
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Reported-by: N"West, Steve (NSN - US/Fort Worth)" <steve.west@nsn.com>
CC: Vlad Yasevich <vyasevich@gmail.com>
CC: netdev@vger.kernel.org
CC: davem@davemloft.net
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>