In the event that our entire receive buffer is full with a series of
chunks that represent a single gap-ack, and then we accept a chunk
(or chunks) that fill in the gap between the ctsn and the first gap,
we renege chunks from the end of the buffer, which effectively does
nothing but move our gap to the end of our received tsn stream. This
does little but move our missing tsns down stream a little, and, if the
sender is sending sufficiently large retransmit frames, the result is a
perpetual slowdown which can never be recovered from, since the only
chunk that can be accepted to allow progress in the tsn stream necessitates
that a new gap be created to make room for it. This leads to a constant
need for retransmits, and subsequent receiver stalls. The fix I've come up
with is to deliver the frame without reneging if we have a full receive
buffer and the receiving sockets sk_receive_queue is empty(indicating that
the receive buffer is being blocked by a missing tsn).
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Right now, every time we increase our rwnd by more then MTU bytes, we
trigger a SACK. When processing large messages, this will generate a
SACK for almost every other SCTP fragment. However since we are freeing
the entire message at the same time, we might as well collapse the SACK
generation to 1.
Signed-off-by: Tsutomu Fujii <t-fujii@nb.jp.nec.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When using ASSOCINFO socket option, we need to limit the number of
maximum association retransmissions to be no greater than the sum
of all the path retransmissions. This is specified in Section 7.1.2
of the SCTP socket API draft.
However, we only do this if the association has multiple paths. If
there is only one path, the protocol stack will use the
assoc_max_retrans setting when trying to retransmit packets.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Enable SO_LINGER functionality for 1-N style sockets. The socket API
draft will be clarfied to allow for this functionality. The linger
settings will apply to all associations on a given socket.
Signed-off-by: Vladislav Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
If SCTP receives a badly formatted HB-ACK chunk, it is possible
that we may access invalid memory and potentially have a buffer
overflow. We should really make sure that the chunk format is
what we expect, before attempting to touch the data.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
sctp_rcv().
The goal is to hold the ref on the association/endpoint throughout the
state-machine process. We accomplish like this:
/* ref on the assoc/ep is taken during lookup */
if owned_by_user(sk)
sctp_add_backlog(skb, sk);
else
inqueue_push(skb, sk);
/* drop the ref on the assoc/ep */
However, in sctp_add_backlog() we take the ref on assoc/ep and hold it
while the skb is on the backlog queue. This allows us to get rid of the
sock_hold/sock_put in the lookup routines.
Now sctp_backlog_rcv() needs to account for potential association move.
In the unlikely event that association moved, we need to retest if the
new socket is locked by user. If we don't this, we may have two packets
racing up the stack toward the same socket and we can't deal with it.
If the new socket is still locked, we'll just add the skb to its backlog
continuing to hold the ref on the association. This get's rid of the
need to move packets from one backlog to another and it also safe in
case new packets arrive on the same backlog queue.
The last step, is to lock the new socket when we are moving the
association to it. This is needed in case any new packets arrive on
the association when it moved. We want these to go to the backlog since
we would like to avoid the race between this new packet and a packet
that may be sitting on the backlog queue of the old socket toward the
same association.
Signed-off-by: Vladislav Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Discard an unexpected chunk in CLOSED state rather can calling BUG().
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use pskb_pull() to handle incoming COOKIE_ECHO and HEARTBEAT chunks that
are received as skb's with fragment list.
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is a rare situation that causes lksctp to go into infinite recursion
and crash the system. The trigger is a packet that contains at least the
first two DATA fragments of a message bundled together. The recursion is
triggered when the user data buffer is smaller that the full data message.
The problem is that we clone the skb for every fragment in the message.
When reassembling the full message, we try to link skbs from the "first
fragment" clone using the frag_list. However, since the frag_list is shared
between two clones in this rare situation, we end up setting the frag_list
pointer of the second fragment to point to itself. This causes
sctp_skb_pull() to potentially recurse indefinitely.
Proposed solution is to make a copy of the skb when attempting to link
things using frag_list.
Signed-off-by: Vladislav Yasevich <vladsilav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes a deadlock situation in the receive path by allowing
temporary spillover of the receive buffer.
- If the chunk we receive has a tsn that immediately follows the ctsn,
accept it even if we run out of receive buffer space and renege data with
higher TSNs.
- Once we accept one chunk in a packet, accept all the remaining chunks
even if we run out of receive buffer space.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Mark Butler <butlerm@middle.net>
Acked-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
for_each_cpu() actually iterates across all possible CPUs. We've had mistakes
in the past where people were using for_each_cpu() where they should have been
iterating across only online or present CPUs. This is inefficient and
possibly buggy.
We're renaming for_each_cpu() to for_each_possible_cpu() to avoid this in the
future.
This patch replaces for_each_cpu with for_each_possible_cpu under /net
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6:
[NETFILTER] x_table.c: sem2mutex
[IPV4]: Aggregate route entries with different TOS values
[TCP]: Mark tcp_*mem[] __read_mostly.
[TCP]: Set default max buffers from memory pool size
[SCTP]: Fix up sctp_rcv return value
[NET]: Take RTNL when unregistering notifier
[WIRELESS]: Fix config dependencies.
[NET]: Fill in a 32-bit hole in struct sock on 64-bit platforms.
[NET]: Ensure device name passed to SO_BINDTODEVICE is NULL terminated.
[MODULES]: Don't allow statically declared exports
[BRIDGE]: Unaligned accesses in the ethernet bridge
Implement the half-closed devices notifiation, by adding a new POLLRDHUP
(and its alias EPOLLRDHUP) bit to the existing poll/select sets. Since the
existing POLLHUP handling, that does not report correctly half-closed
devices, was feared to be changed, this implementation leaves the current
POLLHUP reporting unchanged and simply add a new bit that is set in the few
places where it makes sense. The same thing was discussed and conceptually
agreed quite some time ago:
http://lkml.org/lkml/2003/7/12/116
Since this new event bit is added to the existing Linux poll infrastruture,
even the existing poll/select system calls will be able to use it. As far
as the existing POLLHUP handling, the patch leaves it as is. The
pollrdhup-2.6.16.rc5-0.10.diff defines the POLLRDHUP for all the existing
archs and sets the bit in the six relevant files. The other attached diff
is the simple change required to sys/epoll.h to add the EPOLLRDHUP
definition.
There is "a stupid program" to test POLLRDHUP delivery here:
http://www.xmailserver.org/pollrdhup-test.c
It tests poll(2), but since the delivery is same epoll(2) will work equally.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I was working on the ipip/xfrm problem and as usual I get side-tracked by
other problems.
As part of an attempt to change the IPv4 protocol handler calling
convention I found that SCTP violated the existing convention.
It's returning non-zero values after freeing the skb. This is doubly bad
as 1) the skb gets resubmitted; 2) the return value is interpreted as a
protocol number.
This patch changes those return values to zero.
IPv6 doesn't suffer from this problem because it uses a positive return
value as an indication for resubmission. So the only effect of this patch
there is to increment the IPSTATS_MIB_INDELIVERS counter which IMHO is
the right thing to do.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
No code changes, just tidying up, in some cases moving EXPORT_SYMBOLs
to just after the function exported, etc.
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch extends {get|set}sockopt compatibility layer in order to
move protocol specific parts to their place and avoid huge universal
net/compat.c file in the future.
Signed-off-by: Dmitry Mishin <dim@openvz.org>
Signed-off-by: David 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: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The number of HEARTBEAT chunks that an association may transmit is
limited by Association.Max.Retrans count; however, the code allows
us to send one extra heartbeat.
This patch limits the number of heartbeats to the maximum count.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We currently count the initial INIT/COOKIE_ECHO chunk toward the
retransmit count and thus sends a total of sctp_max_retrans_init chunks.
The correct behavior is to retransmit the chunk sctp_max_retrans_init in
addition to sending the original.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
