CTC Driver May Incorrectly Discard Datagrams With
DTCCTC008E Message Produced

 
 APAR Identifier ...... PQ34318      Last Changed ........ 00/08/07
 CTC DRIVER MAY INCORRECTLY DISCARD DATAGRAMS WITH DTCCTC008E
 MESSAGE PRODUCED
 
 Symptom ...... IN INCORROUT         Status ........... CLOSED  PER
 Severity ................... 3      Date Closed ......... 00/01/06
 Component .......... 5735FAL00      Duplicate of ........
 Reported Release ......... 320      Fixed Release ............ 999
 Component Name TCP/IP V2 FOR V      Special Notice
 Current Target Date ..              Flags
 SCP ...................
 Platform ............
 
 Status Detail: SHIPMENT - Packaged solution is available for
                           shipment.
 
 PE PTF List:
 
 PTF List:
 Release 240   : UQ39085 available 00/01/13 (1000 )
 Release 310   : UQ39086 available 00/01/13 (0001 )
 Release 320   : UQ39087 available 00/01/13 (0001 )
 
 Parent APAR:
 Child APAR list:
 
 ERROR DESCRIPTION:
 If a datagram ends within 6 bytes of the end of the CTC write
 buffer, it will be discarded by the read side and message
 DTCCTC008E will be produced.
 
 This problem is equivalent to that reported by MVS CS/390
 APAR PN80905.
 
 LOCAL FIX:
 None.
 
 PROBLEM SUMMARY:
 ****************************************************************
 * USERS AFFECTED: Users with real or virtual                   *
 *                 channel-to-channel adapter (CTCA)            *
 *                 connections to VM TCP/IP and especially      *
 *                 users running Linux for S/390 with such      *
 *                 connections.                                 *
 ****************************************************************
 * PROBLEM DESCRIPTION:                                         *
 ****************************************************************
 * RECOMMENDATION: APPLY PTF                                    *
 ****************************************************************
 A packet at the end of a buffer received over a real or virtual
 channel-to-channel adapter (CTCA) connection will be dropped if
 its last byte is in the last seven bytes of the buffer area.
 This problem does not generally affect connections between two
 VM TCP/IP stacks or between VM and MVS.  In most cases, the
 dropped packet will be retransmitted by the sender, resulting in
 a small decline in performance.  However, if a single packet
 occupies the entire buffer area, it will always be dropped and
 thus will never be transmitted successfully.  Buffers like this
 may be created by Linux for S/390.
 
 PROBLEM CONCLUSION:
 Code has been changed to allow a packet to occupy any of the
 last seven bytes of the CTCA input buffer.
 
 TEMPORARY FIX:
 
 COMMENTS:
 
 MODULES/MACROS:   TCPIP    TCTOCTC
 
 SRLS:      NONE
 
 RTN CODES:
 
 CIRCUMVENTION:
 
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