IC75344: PCOM: TN3270 SESSION HANGS IF THE SESSION DETECTED PROG ERROR BEFORE RECEIVING IAC EOR (0XFFEF) OF THE RU

Personal Communications 5.9.8

APAR status

• Closed as program error.

Error description

• Customer is using Pcom and connecting to legacy TN3270
  gateway ( CICTELD ) included in TX Series/AIX.
  If PROG error occurs, user cannot reset it by pressing reset key
  Under this condition, if user tries to disconnect the session
  by selecting communication -> disconnect, then mouse pointer
  remains sandglass mark.
  Note that Prog error itself was caused by host application
  that sent invalid format of 3270 data.
  .
  The telnet gateway included in TX has a habit of sending
  IAC EOR (0xffef) by a separate packet.
  If pcom detects error in a chunk of screen data,
  it seems that Pcom stop processing the further packets so that
  Pcom does not process IAC EOR that comes in by the following
  packet
  so that Pcom is waiting IAC EOR forever that prevents user from
  recovering the session.
  .
  If Pcom receives invalid data and 0xffef in the same chunk
  user can reset prog error and disconnect the session
  successfully.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All legacy TN3270 gateway users              *
  ****************************************************************
  * PROBLEM DESCRIPTION: If a PROG error occurs on a TN3270      *
  *                      display session, it can be cleared by   *
  *                      the RESET key but the session can not   *
  *                      be disconnected.                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  If Pcom detects an error in a chunk of screen data, it stops
  processing the remainder of the packet and does not process
  the IAC EOR that comes in the next packet. Therefore, Pcom
  is waiting on IAC EOR forever which prevents the user from
  recovering the session.
  

Problem conclusion

• PCSTLNET.DLL has been changed to pre-receive two bytes of data
  from next chunk, and if it is IAC EOR (0xffef) then it will be
  concatenated to the current chunk of data and this will prevent
  the hang situation that occurs during disconnect.
  
  Fix scheduled for PCOM 5.9.8 Refresh Pack
  Fix scheduled for PCOM 6.0.3 Refresh Pack
  

Temporary fix

• Yes
  

Comments

APAR Information

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

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

Modules/Macros

• PCSTLNET
  

Fix information

• Fixed component name

  PCOMM V5 COMBO-

• Fixed component ID

  5639I700J

Applicable component levels

• R590 PSN

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