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: MESSAGE TO SUBMITTER: