When retransmitting due to T3 timeout, retransmit all the
in-flight chunks for the corresponding  transport/path, including
chunks sent less then 1 rto ago.
This is the correct behaviour according to rfc4960 section 6.3.3
E3 and
"Note: Any DATA chunks that were sent to the address for which the
 T3-rtx timer expired but did not fit in one MTU (rule E3 above)
 should be marked for retransmission and sent as soon as cwnd
 allows (normally, when a SACK arrives). ".

This fixes problems when more then one path is present and the T3
retransmission of the first chunk that timeouts stops the T3 timer
for the initial active path, leaving all the other in-flight
chunks waiting forever or until a new chunk is transmitted on the
same path and timeouts (and this will happen only if the cwnd
allows sending new chunks, but since cwnd was dropped to MTU by
the timeout => it will wait until the first heartbeat).

Example: 10 packets in flight, sent at 0.1 s intervals on the
primary path. The primary path is down and the first packet
timeouts. The first packet is retransmitted on another path, the
T3 timer for the primary path is stopped and cwnd is set to MTU.
All the other 9 in-flight packets will not be retransmitted
(unless more new packets are sent on the primary path which depend
on cwnd allowing it, and even in this case the 9 packets will be
retransmitted only after a new packet timeouts which even in the
best case would be more then RTO).

This commit reverts d0ce9291 and
also removes the now unused transport->last_rto, introduced in
 b6157d8e.

p.s  The problem is not only when multiple paths are there.  It
can happen in a single homed environment.  If the application
stops sending data, it possible to have a hung association.
Signed-off-by: NAndrei Pelinescu-Onciul <andrei@iptel.org>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add-IP feature allows users to delete an active transport.  If that
transport has chunks in flight, those chunks need to be moved to another
transport or association may get into unrecoverable state.
Reported-by: NRafael Laufer <rlaufer@cisco.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

RFC3758 Section 3.3.1.  Sending Forward-TSN-Supported param in INIT

   Note that if the endpoint chooses NOT to include the parameter, then
   at no time during the life of the association can it send or process
   a FORWARD TSN.

If peer does not support PR-SCTP capable, don't send FORWARD-TSN chunk
to peer.
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The functions time_before or time_after are more robust
for comparing jiffies against other values.
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 62aeaff5
(sctp: Start T3-RTX timer when fast retransmitting lowest TSN)
introduced a regression where it was possible to forcibly
restart the sctp retransmit timer at the transmission of any
new chunk.  This resulted in much longer timeout times and
sometimes hung sctp connections.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sctp_chunks should be put on a diet.  This is some of the low hanging
fruit that we can strip out.  Changes all the __s8/__u8 flags to
bitfields.  Saves 12 bytes per chunk.
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

Chunks placed on the retransmit list are marked as inelegible
for fast retrasnmission.   Since missing indications determine
when fast reransmission is done, there is not point in calling
sctp_mark_missing() on the retransmit list since those chunks
will not be marked.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

There is a possibility of walking the transport list twice during
SACK processing when doing SFR-CACC algorithm.  We can restructure
the code to only do this once.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

Frist small step in optimizing SACK processing.   Do not call
sctp_mark_missing() when there are no gaps reported and thus
not missing chunks.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

sctp_outq_flush() can now become static.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RFC 4960, Section 11.4. Protection of Non-SCTP-Capable Hosts

When an SCTP stack receives a packet containing multiple control or
DATA chunks and the processing of the packet requires the sending of
multiple chunks in response, the sender of the response chunk(s) MUST
NOT send more than one packet.  If bundling is supported, multiple
response chunks that fit into a single packet MAY be bundled together
into one single response packet.  If bundling is not supported, then
the sender MUST NOT send more than one response chunk and MUST
discard all other responses.  Note that this rule does NOT apply to a
SACK chunk, since a SACK chunk is, in itself, a response to DATA and
a SACK does not require a response of more DATA.

We implement this by not servicing our outqueue until we reach the end
of the packet.  This enables maximum bundling.  We also identify
'response' chunks and make sure that we only send 1 packet when sending
such chunks.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When fast retransmit is triggered by a sack, we should flush the queue
only once so that only 1 retransmit happens.  Also, since we could
potentially have non-fast-rtx chunks on the retransmit queue, we need
make sure any chunks eligable for fast retransmit are sent first
during fast retransmission.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Tested-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we are trying to fast retransmit the lowest outstanding TSN, we
need to restart the T3-RTX timer, so that subsequent timeouts will
correctly tag all the packets necessary for retransmissions.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Tested-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

According to RFC4960 7.2.2, 
When all of the data transmitted by the sender has
been acknowledged by the recerver, partial_bytes_acked is initialized to 0.

This patch conforms to rfc requirement. 
Without this fix, cwnd might be error incremented.
Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com>
Acked-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replacing (almost) all invocations of list_for_each() with
list_for_each_entry() tightens up the code and allows for the deletion
of numerous list iterator variables that are no longer necessary.
Signed-off-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When receiving an error length INIT-ACK during COOKIE-WAIT,
a 0-vtag ABORT will be responsed. This action violates the
protocol apparently. This patch achieves the following things.
1 If the INIT-ACK contains all the fixed parameters, use init-tag
  recorded from INIT-ACK as vtag.
2 If the INIT-ACK doesn't contain all the fixed parameters,
  just reflect its vtag.
Signed-off-by: NGui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RFC 3873 specifies several MIB objects that can't be obtained by the
current data set exported by /proc/sys/net/sctp/assoc.  This patch
adds the missing pieces of data that allow us to compute all the
objects in the sctpAssocTable object.
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In a few instances, we need to remove the chunk from the transmitted list
prior to freeing it.  This is because the free code doesn't do that any
more and so we need to do it manually.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

I was notified by Randy Stewart that lksctp claims to be
"the reference implementation".  First of all, "the
refrence implementation" was the original implementation
of SCTP in usersapce written ty Randy and a few others.
Second, after looking at the definiton of 'reference implementation',
we don't really meet the requirements.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

The processing of the ASCONF chunks has changed a lot in the
spec.  New items are:
    1. A list of ASCONF-ACK chunks is now cached
    2. The source of the packet is used in response.
    3. New handling for unexpect ASCONF chunks.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When the code calls uncork, trigger a queue flush, even
if the queue was not corked.  Most callers that explicitely
cork the queue will have additinal checks to see if they 
corked it.  Callers who do not cork the queue expect packets
to flow when they call uncork.

The scneario that showcased this bug happend when we were not
able to bundle DATA with outgoing COOKIE-ECHO.  As a result
the data just sat in the outqueue and did not get transmitted.
The application expected a response, but nothing happened.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

Commit d0ce9291 broke several retransmit
cases including fast retransmit.  The reason is that we should
only delay by rto while doing retranmists as a result of a timeout.
Retransmit as a result of path mtu discover, fast retransmit, or
other evernts that should trigger immidiate retransmissions got broken.

Also, since rto is doubled prior to marking of packets elegable for
retransmission, we never marked correct chunks anyway.

The fix is provide a reason for a given retransmission so that we
can mark chunks appropriately and to save the old rto value to do
comparisons against.

All regressions tests passed with this code.

Spotted by Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

Just fix the bad format of the comment in outqueue.c.
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

When performing a retransmit, do not include the chunk if
it was sent less then 1 rtt ago.  The reason is that we
may receive the SACK very soon and wouldn't retransmit.
Suggested by Randy Stewart.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

Spring cleaning time...

There seems to be a lot of places in the network code that have
extra bogus semicolons after conditionals.  Most commonly is a
bogus semicolon after: switch() { }
Signed-off-by: NStephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The problem that this patch corrects happens when all of the following
conditions are satisfisfied:
 1.  PR-SCTP is used and the timeout on the chunks is set below RTO.Max.
 2.  One of the paths on a multihomed associations is brought down.

In this scenario, data will expire within the rto of the initial
transmission and will never be retransmitted.  However this data still
fills the send buffer and is counted against the association as outstanding
data.  This causes any new data not to be sent and retransmission to not
happen.

The fix is to discount the abandoned data from the outstanding count and
peers rwnd estimation.  This allows new data to be sent and a retransmission
timer restarted.  Even though this new data will most likely expire within
the rto, the timer still counts as a strike against the transport and forces
the FORWARD-TSN chunk to be retransmitted as well.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently if the sender is sending small messages, it can cause a receiver
to run out of receive buffer space even when the advertised receive window
is still open and results in packet drops and retransmissions. Including
a overhead while updating the sender's view of peer receive window will
reduce the chances of receive buffer space overshooting the receive window.
Signed-off-by: NSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds more statistics info under /proc/net/sctp/snmp
that should be useful for debugging. The additional events that
are counted now include timer expirations, retransmits, packet
and data chunk discards.

The Data chunk discards include all the cases where a data chunk
is discarded including high tsn, bad stream, dup tsn and the most
useful one(out of receive buffer/rwnd).

Also moved the SCTP MIB data structures from the generic include
directories to include/sctp/sctp.h.
Signed-off-by: NSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch implements Path Initialization procedure as described in
Sec 2.36 of RFC4460.
Signed-off-by: NSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

SCTP used to "fast retransmit" a TSN every time we hit the number
of missing reports for the TSN.  However the Implementers Guide
specifies that we should only "fast retransmit" a given TSN once.
Subsequent retransmits should be timeouts only. Also change the
number of missing reports to 3 as per the latest IG(similar to TCP).
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implements sctp_connectx() as defined in the SCTP sockets API draft by
tunneling the request through a setsockopt().
Signed-off-by: NFrank Filz <ffilzlnx@us.ibm.com>
Signed-off-by: NSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!