Messages in this thread | | | Date | Fri, 7 Jun 2013 18:39:34 +0800 | From | Xufeng Zhang <> | Subject | Re: [PATCH] sctp: set association state to established in dupcook_a handler |
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Hi David,
Is this fix fine to you for -stable?
Thanks, Xufeng
On 06/05/2013 10:55 AM, Xufeng Zhang wrote: > 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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