Messages in this thread Patch in this message | | | Date | Wed, 5 Jun 2013 10:55:50 +0800 | From | Xufeng Zhang <> | Subject | Re: [PATCH] sctp: set association state to established in dupcook_a handler |
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On 06/03/2013 03:52 PM, Xufeng Zhang wrote: > 3.4-stable review patch. If anyone has any objections, please let me know. > Sorry Greg, David -- I did not fully understand all the details of the stable kernel process earlier.
I have since checked the networking stable queue here:
http://patchwork.ozlabs.org/bundle/davem/stable/?state=*
to confirm this upstream commit 9839ff0d has not yet been queued.
It can be applied to kernel versions<3.0, 3.4>, and is present in mainline for 3.8+ kernels.
I think it makes sense to queue for stable because it fixes the SCTP association can get stuck in SCTP_STATE_SHUTDOWN_PENDING state forever in the below test case: 1). Set SCTP parameters on A (slow detection of link failure): net.sctp.association_max_retrans = 5 net.sctp.path_max_retrans = 5 net.sctp.hb_interval = 30000 2). Set SCTP parameters on B (fast detection of link failure): net.sctp.association_max_retrans = 2 net.sctp.path_max_retrans = 2 net.sctp.hb_interval = 1000 3). Start sctp_darn on both sides: A(interactive): sctp_darn -H 192.168.100.10 -P 256 -h 192.168.100.100 -p 256 -I -s B: sctp_darn -H 192.168.100.100 -P 256 -h 192.168.100.10 -p 256 -l& 4). Send data on A to establish the SCTP association: snd=5 5). Block SCTP traffic on B (simulates a network failure): iptables -t filter -I INPUT 1 -p sctp --dport 256 -j DROP iptables -t filter -I OUTPUT 1 -p sctp --dport 256 -j DROP Then quickly send data on A and then shutdown (A goes into SHUTDOWN_PENDING state): snd=5 snd=5 shutdown 6). Wait for link to drop on B (Recieved SCTP_COMM_LOST), and quickly kill the listener, open the firewall for SCTP, then start an SCTP sender: kill $PID iptables -t filter -D INPUT 1 iptables -t filter -D OUTPUT 1 sctp_darn -H 192.168.100.100 -P 256 -h 192.168.100.10 -p 256 -s Press<Enter> to send data to trigger sending INIT to A, the SHUTDOWN on A will failed and the association on A remains in SHUTDOWN_PENDING (5) state indefinitely.
However if David doesn't think it is worth bothering with for net stable, then that is of course fine too.
Thanks, Xufeng
> ------------------ > > > From: Xufeng Zhang<xufeng.zhang@windriver.com> > > [ Upstream commit 9839ff0dead906e85e4d17490aeff87a5859a157 ] > > While sctp handling a duplicate COOKIE-ECHO and the action is > 'Association restart', sctp_sf_do_dupcook_a() will processing > the unexpected COOKIE-ECHO for peer restart, but it does not set > the association state to SCTP_STATE_ESTABLISHED, so the association > could stuck in SCTP_STATE_SHUTDOWN_PENDING state forever. > This violates the sctp specification: > RFC 4960 5.2.4. Handle a COOKIE ECHO when a TCB Exists > Action > A) In this case, the peer may have restarted. ..... > After this, the endpoint shall enter the ESTABLISHED state. > > To resolve this problem, adding a SCTP_CMD_NEW_STATE cmd to the > command list before SCTP_CMD_REPLY cmd, this will set the restart > association to SCTP_STATE_ESTABLISHED state properly and also avoid > I-bit being set in the DATA chunk header when COOKIE_ACK is bundled > with DATA chunks. > > Signed-off-by: Xufeng Zhang<xufeng.zhang@windriver.com> > Acked-by: Neil Horman<nhorman@tuxdriver.com> > Acked-by: Vlad Yasevich<vyasevich@gmail.com> > Signed-off-by: David S. Miller<davem@davemloft.net> > --- > net/sctp/sm_statefuns.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c > index cb1c430..ab08f65 100644 > --- a/net/sctp/sm_statefuns.c > +++ b/net/sctp/sm_statefuns.c > @@ -1747,8 +1747,10 @@ static sctp_disposition_t sctp_sf_do_dupcook_a(const struct sctp_endpoint *ep, > > /* Update the content of current association. */ > sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc)); > - sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); > sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); > + sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, > + SCTP_STATE(SCTP_STATE_ESTABLISHED)); > + sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); > return SCTP_DISPOSITION_CONSUME; > > nomem_ev: >
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