PM62348: CICS NOT NOTIFIED OF UNRESPONSIVE OR IDLE SOCKET CONNECTION

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• An IPIC connection (IPCONN) to a TxSeries is suddenly severed
  but CICS does not appear to be notified via a Socket Close being
  received.
    For an application to be notified that a socket connection
  partner has become unresponsive on an idle connection, the
  application must enable this function by issuing
  SETSOCKOPT OPTNAME=SO_KEEPALIVE.  If a nonzero OPTVAL is
  coded on this macro, then that will enable the keep alive
  mechanism for the socket specified on the macro. When
  activated, the keep alive mechanism periodically sends a
  packet on an otherwise idle connection. If the remote TCP
  does not respond to the packet or to re-transmissions of
  the packet, the connection is terminated with the error
  ETIMEDOUT.
     If this mechanism is not so enabled by the application,
  even the 120-minute default value for SO_KEEPALIVE will not
  be in effect for the socket.
     The default SO_KEEPALIVE value of 120 minutes is a
  relatively long time, so if the application should be
  informed of a nonresponsive partner sooner than that.
     There are a few ways to do this but the only feesable
  way for CICS would be to issue
  SETSOCKOPT OPTNAME=TCP_KEEPALIVE  to specify a a
  socket-specific timeout value to be used in place of the
  configuration-specific keep alive value whenever the keep
  alive mechanism is active for that socket. The value can be
  specified in the range from 1 to 2,147,460 seconds. (If a
  value of 0 is coded the keep alive function is disabled for
  the socket)
     When a timer value is in place and a connection has been
  idle for the time specified, TCP will send a keepalive probe
  to the partner. If the partner does not respond to the probe,
  a number of these probes will be re-transmitted at a specific
  interval. When these retries are exhausted, the application
  will be informed of the connection termination.
     This APAR has been taken to investigate CICS providing a
  shorter keepalive time interval.
  .
  ADDITIONAL KEYWORDS:
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All CICS users.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: CICS is connected to an IPIC partner on *
  *                      a TXseries box. When the TXseries box   *
  *                      is terminated abruptly, CICS is not     *
  *                      notified and the IPCONN is still in ACQ *
  *                      status.                                 *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  IPIC connection is set up between CICS TS and TXseries box.
  During the IPCONN acquiring process, CICS activates the TCPIP
  KEEPALIVE mechanism for sockets by setting SO_KEEPALIVE.
  The default interval 120 minutes is a relatively long time.
  When TXseries box powers off (or has some other major
  failure requiring a restart), CICS will not get notification
  that the remote system is unresponsive sooner than the KEEPALIVE
  interval in the TCPIP profile and the IPCONN will keep Acquire
  status.
  When the remote system restarts and tries to acquire the IPIC
  connection, CICS realizes the required IPCONN is still in ACQ
  status, which causes exception INVALID_PARTNER_STATE and
  MESSAGE DFHIS1015 is raised.
  

Problem conclusion

• Sockets Domain has been changed so that CICS can provide
  a shorter KEEPALIVE interval of 120 seconds.
  
  The CICS Transaction Server for z/OS Version 3 Release 2
  Supplementary Data Areas, GC34-6864-04 will be altered
  in Chapter 'SOA Sockets Anchor block' under page 1126 to
  insert a new row in table 604 to add a field
  SOA_TCP_KEEPALIVE into the SOA socket anchor block.
  
  The new row will be added before the row with 'Name' column
  equal to 'SOA_PAD1' as follows:
  
  Offset  Type     Len   Name             Description
  Hex
  (184)  FULLWORD   4   SOA_TCP_KEEPALIVE tcp keepalive interval
  (188)  CHARACTER  0   SOA_PAD1
  (188)  CHARACTER  120   *
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  PM59599

• APAR is sysrouted TO one or more of the following:

  UK79565

Modules/Macros

•    DESSOAN  DESSOCK  DESSODM  DESSOLS  DESSOSO
  DESSOUS  DESWBCL  DFHSOANC DFHSOAND DFHSOCBA DFHSOCBM DFHSOCBT
  DFHSOCCC DFHSOCK  DFHSOCKA DFHSOCKJ DFHSOCKM DFHSOCKT DFHSOCKV
  DFHSODCC DFHSODM  DFHSOLS  DFHSOREC DFHSOSOC DFHSOS00 DFHSOS01
  DFHSOS02 DFHSOS03 DFHSOS04 DFHSOS05 DFHSOS06 DFHSOS07 DFHSOS08
  DFHSOS09 DFHSOS10 DFHSOS11 DFHSOS12 DFHSOS13 DFHSOS14 DFHSOS15
  DFHSOS16 DFHSOS17 DFHSOS18 DFHSOS19 DFHSOS20 DFHSOS21 DFHSOS22
  DFHSOS23 DFHSOUSC DFHWBCL
  

Fix information

• Fixed component name

  CICSTS V3 Z/OS

• Fixed component ID

  5655M1500

Applicable component levels

• R500 PSY UK79565

     UP12/06/19 P F206

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.