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 d0ce92910b and
also removes the now unused transport->last_rto, introduced in
b6157d8e03.
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: Andrei Pelinescu-Onciul <andrei@iptel.org>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Current implementation of max.burst ends up limiting new
data during cwnd decay period. The decay is happening becuase
the connection is idle and we are allowed to fill the congestion
window. The point of max.burst is to limit micro-bursts in response
to large acks. This still happens, as max.burst is still applied
to each transmit opportunity. It will also apply if a very large
send is made (greater then allowed by burst).
Tested-by: Florian Niederbacher <florian.niederbacher@student.uibk.ac.at>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
The transport last_time_used variable is rather useless.
It was only used when determining if CWND needs to be updated
due to idle transport. However, idle transport detection was
based on a Heartbeat timer and last_time_used was not incremented
when sending Heartbeats. As a result the check for cwnd reduction
was always true. We can get rid of the variable and just base
our cwnd manipulation on the HB timer (like the code comment sais).
We also have to call into the cwnd manipulation function regardless
of whether HBs are enabled or not. That way we will detect idle
transports if the user has disabled Heartbeats.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
We currently send window update SACKs every time we free up 1 PMTU
worth of data. That a lot more SACKs then necessary. Instead, we'll
now send back the actuall window every time we send a sack, and do
window-update SACKs when a fraction of the receive buffer has been
opened. The fraction is controlled with a sysctl.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Recent commit 8da645e101
sctp: Get rid of an extra routing lookup when adding a transport
introduced a regression in the connection setup. The behavior was
different between IPv4 and IPv6. IPv4 case ended up working because the
route lookup routing returned a NULL route, which triggered another
route lookup later in the output patch that succeeded. In the IPv6 case,
a valid route was returned for first call, but we could not find a valid
source address at the time since the source addresses were not set on the
association yet. Thus resulted in a hung connection.
The solution is to set the source addresses on the association prior to
adding peers.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This provides safety against negative optlen at the type
level instead of depending upon (sometimes non-trivial)
checks against this sprinkled all over the the place, in
each and every implementation.
Based upon work done by Arjan van de Ven and feedback
from Linus Torvalds.
Signed-off-by: David S. Miller <davem@davemloft.net>
This shrinks the size of struct sctp_association a little.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
This patch introduces a new sysctl option to make IPv4 Address Scoping
configurable <draft-stewart-tsvwg-sctp-ipv4-00.txt>.
In networking environments where DNAT rules in iptables prerouting
chains convert destination IP's to link-local/private IP addresses,
SCTP connections fail to establish as the INIT chunk is dropped by the
kernel due to address scope match failure.
For example to support overlapping IP addresses (same IP address with
different vlan id) a Layer-5 application listens on link local IP's,
and there is a DNAT rule that maps the destination IP to a link local
IP. Such applications never get the SCTP INIT if the address-scoping
draft is strictly followed.
This sysctl configuration allows SCTP to function in such
unconventional networking environments.
Sysctl options:
0 - Disable IPv4 address scoping draft altogether
1 - Enable IPv4 address scoping (default, current behavior)
2 - Enable address scoping but allow IPv4 private addresses in init/init-ack
3 - Enable address scoping but allow IPv4 link local address in init/init-ack
Signed-off-by: Bhaskar Dutta <bhaskar.dutta@globallogic.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
We had a bug that we never stored the user-defined value for
MAXSEG when setting the value on an association. Thus future
PMTU events ended up re-writing the frag point and increasing
it past user limit. Additionally, when setting the option on
the socket/endpoint, we effect all current associations, which
is against spec.
Now, we store the user 'maxseg' value along with the computed
'frag_point'. We inherit 'maxseg' from the socket at association
creation and use it as an upper limit for 'frag_point' when its
set.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
SCTP will delay the last part of a large write due to NAGLE, if that
part is smaller then MTU. Since we are doing large writes, we might
as well send the last portion now instead of waiting untill the next
large write happens. The small portion will be sent as is regardless,
so it's better to not delay it.
This is a result of much discussions with Wei Yongjun <yjwei@cn.fujitsu.com>
and Doug Graham <dgraham@nortel.com>. Many thanks go out to them.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
SCTP has a problem that when small chunks are used, it is possible
to exhaust the receiver buffer without fully closing receive window.
This happens due to all overhead that we have account for with small
messages. To fix this, when receive buffer is exceeded, we'll drop
the window to 0 and save the 'drop' portion. When application starts
reading data and freeing up recevie buffer space, we'll wait until
we've reached the 'drop' window and then add back this 'drop' one
mtu at a time. This worked well in testing and under stress produced
rather even recovery.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Currenlty, sctp breaks up user messages into fragments and
sends each fragment to the lower layer by itself. This means
that for each fragment we go all the way down the stack
and back up. This also discourages bundling of multiple
fragments when they can fit into a sigle packet (ex: due
to user setting a low fragmentation threashold).
We introduce a new command SCTP_CMD_SND_MSG and hand the
whole message down state machine. The state machine and
the side-effect parser will cork the queue, add all chunks
from the message to the queue, and then un-cork the queue
thus causing the chunks to get transmitted.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
RFC 5061 Section 5.1 ASCONF Chunk Procedures said:
B4) Re-transmit the ASCONF Chunk last sent and if possible choose an
alternate destination address (please refer to [RFC4960],
Section 6.4.1). An endpoint MUST NOT add new parameters to this
chunk; it MUST be the same (including its Sequence Number) as
the last ASCONF sent. An endpoint MAY, however, bundle an
additional ASCONF with new ASCONF parameters with the next
Sequence Number. For details, see Section 5.5.
This patch fix to choose an alternate destination address when
re-transmit the ASCONF chunk, with some dup codes cleanup.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
SCTP incorrectly doubles rto ever time a Hearbeat chunk
is generated. However RFC 4960 states:
On an idle destination address that is allowed to heartbeat, it is
recommended that a HEARTBEAT chunk is sent once per RTO of that
destination address plus the protocol parameter 'HB.interval', with
jittering of +/- 50% of the RTO value, and exponential backoff of the
RTO if the previous HEARTBEAT is unanswered.
Essentially, of if the heartbean is unacknowledged, do we double the RTO.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is a new version of my patch, now using a module parameter instead
of a sysctl, so that the option is harder to find. Please note that,
once the module is loaded, it is still possible to change the value of
the parameter in /sys/module/sctp/parameters/, which is useful if you
want to do performance comparisons without rebooting.
Computation of SCTP checksums significantly affects the performance of
SCTP. For example, using two dual-Opteron 246 connected using a Gbe
network, it was not possible to achieve more than ~730 Mbps, compared to
941 Mbps after disabling SCTP checksums.
Unfortunately, SCTP checksum offloading in NICs is not commonly
available (yet).
By default, checksums are still enabled, of course.
Signed-off-by: Lucas Nussbaum <lucas.nussbaum@ens-lyon.fr>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The tsn map currently use is 4K large and is stuck inside
the sctp_association structure making memory references REALLY
expensive. What we really need is at most 4K worth of bits
so the biggest map we would have is 512 bytes. Also, the
map is only really usefull when we have gaps to store and
report. As such, starting with minimal map of say 32 TSNs (bits)
should be enough for normal low-loss operations. We can grow
the map by some multiple of 32 along with some extra room any
time we receive the TSN which would put us outside of the map
boundry. As we close gaps, we can shift the map to rebase
it on the latest TSN we've seen. This saves 4088 bytes per
association just in the map alone along savings from the now
unnecessary structure members.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_is_any() function that is used to check for wildcard addresses
only looks at the address itself to determine the address family.
This function is used in the API to check the address passed in from
the user. If the user simply zerroes out the sockaddr_storage and
pass that in, we'll end up failing. So, let's try harder to determine
the address family by also checking the socket if it's possible.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
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: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
The ipfragok flag controls whether the packet may be fragmented
either on the local host on beyond. The latter is only valid on
IPv4.
In fact, we never want to do the latter even on IPv4 when PMTU is
enabled. This is because even though we can't fragment packets
within SCTP due to the prtocol's inherent faults, we can still
fragment it at IP layer. By setting the DF bit we will improve
the PMTU process.
RFC 2960 only says that we SHOULD clear the DF bit in this case,
so we're compliant even if we set the DF bit. In fact RFC 4960
no longer has this statement.
Once we make this change, we only need to control the local
fragmentation. There is already a bit in the skb which controls
that, local_df. So this patch sets that instead of using the
ipfragok argument.
The only complication is that there isn't a struct sock object
per transport, so for IPv4 we have to resort to changing the
pmtudisc field for every packet. This should be safe though
as the protocol is single-threaded.
Note that after this patch we can remove ipfragok from the rest
of the stack too.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_outq_flush() can now become static.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David 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: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit e9df2e8fd8 ("[IPV6]: Use
appropriate sock tclass setting for routing lookup.") also changed the
way that ECN capable transports mark this capability in IPv6. As a
result, SCTP was not marking ECN capablity because the traffic class
was never set. This patch brings back the markings for IPv6 traffic.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David 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: Vlad Yasevich <vladislav.yasevich@hp.com>
Tested-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Correctly keep track of Fast Recovery state and do not reduce
congestion window multiple times during sucht state.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Tested-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 7cbca67c07 ("[IPV6]: Support
Source Address Selection API (RFC5014)") introduced NULL dereference
of asoc to sctp_v6_get_saddr in net/sctp/ipv6.c.
Pointed out by Johann Felix Soden <johfel@users.sourceforge.net>.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Brings delayed_ack socket option set/get into line with the latest ietf
socket extensions API draft, while maintaining backwards compatibility.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_datamsg_free and sctp_datamsg_track are just aliases for
sctp_datamsg_put and sctp_chunk_hold, respectively.
Saves 32 Bytes on x86.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David 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: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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: Vlad Yasevich <vladislav.yasevich@hp.com>
ADD-IP spec has a special case for processing ABORTs:
F4) ... One special consideration is that ABORT
Chunks arriving destined to the IP address being deleted MUST be
ignored (see Section 5.3.1 for further details).
Check if the address we received on is in the DEL state, and if
so, ignore the ABORT.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ADD-IP "Set Primary IP Address" parameter is allowed in the
INIT/INIT-ACK exchange. Allow processing of this parameter during
the INIT/INIT-ACK.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The Address Parameter in the parameter list of the ASCONF chunk
may be a wildcard address. In this case special processing
is required. For the 'add' case, the source IP of the packet is
added. In the 'del' case, all addresses except the source IP
of packet are removed. In the "mark primary" case, the source
address is marked as primary.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
During accept/migrate the code attempts to copy the addresses from
the parent endpoint to the new endpoint. However, if the parent
was bound to a wildcard address, then we end up pointlessly copying
all of the current addresses on the system.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch adds a tunable that will allow ADD_IP to work without
AUTH for backward compatibility. The default value is off since
the default value for ADD_IP is off as well. People who need
to use ADD-IP with older implementations take risks of connection
hijacking and should consider upgrading or turning this tunable on.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
After learning more about rcu, it looks like the ADD-IP hadling
doesn't need to call call_rcu_bh. All the rcu critical sections
use rcu_read_lock, so using call_rcu_bh is wrong here.
Now, restore the local_bh_disable() code blocks and use normal
call_rcu() calls. Also restore the missing return statement.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Commit d0ce92910b 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: Vlad Yasevich <vladislav.yasevich@hp.com>
Add port randomization rather than a simple fixed rover
for use with SCTP. This makes it act similar to TCP, UDP, DCCP
when allocating ports.
No longer need port_alloc_lock as well (suggestion by Brian Haley).
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
ADD-IP spec requires AUTH. It is, in fact, dangerous without AUTH.
So, disable ADD-IP functionality if the peer claims to support
ADD-IP, but not AUTH.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
