On 1/23/13, Vlad Yasevich <vyasevich@xxxxxxxxx> wrote: > On 01/23/2013 08:46 AM, Neil Horman wrote: >> On Wed, Jan 23, 2013 at 03:38:40PM +0800, xufengzhang.main@xxxxxxxxx >> wrote: >>> From: Xufeng Zhang <xufeng.zhang@xxxxxxxxxxxxx> >>> >>> 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. >>> >>> Fix this problem by adding a SCTP_CMD_NEW_STATE cmd to the command >>> list so as to set the restart association to SCTP_STATE_ESTABLISHED >>> state properly. >>> >>> Signed-off-by: Xufeng Zhang <xufeng.zhang@xxxxxxxxxxxxx> >>> --- >>> net/sctp/sm_statefuns.c | 2 ++ >>> 1 files changed, 2 insertions(+), 0 deletions(-) >>> >>> diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c >>> index 618ec7e..528f1c8 100644 >>> --- a/net/sctp/sm_statefuns.c >>> +++ b/net/sctp/sm_statefuns.c >>> @@ -1779,6 +1779,8 @@ static sctp_disposition_t >>> sctp_sf_do_dupcook_a(struct net *net, >>> >>> /* 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_NEW_STATE, >>> + SCTP_STATE(SCTP_STATE_ESTABLISHED)); >>> sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); >>> sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); >>> return SCTP_DISPOSITION_CONSUME; >>> -- >>> 1.7.0.2 >>> >>> >> >> Looks reasonable to me, thanks >> >> nit: The RFC indicate the association should enter the ESTABLISHED state >> after >> preforming all other actions, so it seems that the state change should >> occur >> after the ULP event is sent >> > > I have a slight concern here that if we change state last, then any data > that may have been bundled with COOKIE-ACK as part of CMD_REPLY will get > the SACK_IMMEDIATE flag set since we are still in the SHUTDOWN_PENDING > state. > > I would be more correct (and would match sctp_sf_do_5_1D_ce) to > do it in this order: > UPDATE_ASSOC - resets all the congestion/association variables > EVENT_UP - send RESTART to USER > NEW_STATE - set ESTABLISHED state (as per spec) > REPLY - Send cookie-ack along with any pending data. Yep, I agree with you, I'll send V2 patch based on your suggestion. Thanks for your review! Thanks, Xufeng > > -vlad >> Neil >> > > -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
