CICS CD autoinstall 知识

1、CICS 如何确定remote Region 的连接请求，并找出已定义的CD：

When CICS receives a connection request from a remote CICS system, it searches the CD entries in your region to determine whether one already exists for that connection.

The CD attributes that it checks are:

• ConnectionType
• RemoteLUName
• RemoteTCPAddress   （估计是远程region CD定义里的 ListenerName 的LD的定义，或者是TCP/IP 协议里找出来的）
• RemoteTCPPort      （同上）
• ListenerName       （估计是连接的LD 是否是本地CD里的ListenerName）

Also, the CD entry must not be in use by another connection.

2、

CICS automatically creates (autoinstall) a Communications Definitions (CD) entry for an IBM CICS Client when it connects to your region. It also autoinstalls a CD entry if a remote CICS region acquires a CICS family TCP/IP connection to your local region and a suitable CD entry is not already defined in your region.

Irrespective of whether the remote system is an IBM CICS Client or a CICS region, the attributes that are assigned to an autoinstalled CD entry are set from:

• Information that is extracted from the network.
• Information that is received from the remote system. This information is received by the CICS transaction CCIN.
• Information from the CICS supplied program DFHCCINX. This program is called each time an autoinstall takes place. It is passed information about the remote system and can veto the install or change some of the attributes that are assigned to the CD entry. You can customize this program.
• Information that is configured in the default CD entry called "".

cicsget -c cd -r CICSREGIONxxx  "" : 获得默认CD配置值。
可以通过update修改。

The supplied version of DFHCCINX accepts all installation requests. In addition, it does the following:

• Uses the values that are supplied by CICS for the CD entry name (SYSID) and RemoteLUName
• Checks the code page that is received from the remote system. If the remote system requested a code page, DFHCCINX checks whether a iconv conversion template is between the local code page and the remote code page. If a conversion template exists, the received code page is used for the RemoteCodePageTR attribute in the autoinstalled CD entry. If no conversion template exists, or if the remote system did not supply a code page, the code page from the RemoteCodePageTR attribute in the default CD entry "" is used.
• Sets up client security. If the CD entry is for an IBM CICS Client that is using a CICS family TCP/IP connection ECI request, or a cicslterm on Windows, RemoteSysSecurity is set to verify and passwords are checked and discarded. Otherwise RemoteSysSecurity is set to the value from the default CD entry. The LinkUserId is set to the value from the default CD entry for all autoinstalled CD entries.
• Log a message to the CCIN log. DFHCCINX writes a message to the Transient Data queue, CCIN, which is defined to write to a file called:

  
  

  
  

     /var/cics_regions/regionName/data/CCIN.out
  

  For example:

  
  

  
  

   date time CD entry 'TN03' for CICS server 'TNX43W03' has been
                 installed with code page 'ISO8859-1'
  

DFHCCINX is passed a parameter structure in a COMMAREA that contains information about the CD entry that is to be installed or uninstalled. describes this parameter structure.

For an install request, the parameter structure contains the values that CICS is using for some of the CD attributes. It also contains information about the remote system and the type of connection that is used to contact the region. shows the values that can be changed by DFHCCINX. Alternatively, DFHCCINX can veto the installation request by setting the ReturnCode field to 0x10. DFHCCINX can also use EXEC CICS commands to perform any additional set up for the remote system. However, it must not access the principal facility because this is reserved for the use of CICS only.

例子：如何组织Universal Client连接入REGION。

For security reasons, you might want to prevent some or all CD entries from autoinstalling in your region. For example, you might want to disable autoinstall completely, or for a particular connection type. Alternatively, you might choose to allow autoinstall only for particular remote systems.

CICS does not autoinstall a CD entry if DFHCCINX returns ReturnCode=0x10 in its parameter structure. Therefore, you can use the information that is passed to DFHCCINX to restrict when autoinstall is to proceed. In the example below, DFHCCINX is preventing all autoinstall requests for CICS family TCP/IP connections. This would mean that IBM CICS Clients could not connect to your region by using CICS family TCP/IP because they require an autoinstalled CD entry. A remote CICS region could connect across CICS family TCP/IP only if you had explicitly defined a CD entry for it.

    EXEC CICS ADDRESS COMMAREA(Parameters);
 
    if ((Parameters->RequestType == CICS_CCINX_REQUESTTYPE_INSTALL) &&;amp;
        (Parameters->ConnectionType == CICS_CCINX_CTYPE_CICSTCP))
  {
        Parameters->ReturnCode = CICS_CCINX_RETURNCODE_REJECT;
    }

--------------以上摘自cics online 6 manual

----cics真的他妈的太强大了!