Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

#### NDMBK

Prolog

Control Block Contents
NDMBK DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### NDMBK Prolog

     NAME       : HCPNDMBK
     DESCRIPTION: Network Device Message Block
     DSECT      : NDMBK
     FUNCTION   :
                  Define a structure to represent a Network Device Message.
                  One NDMBK exists for to represent each message frame
                  created for a Network Interface Device (NID).
     LOCATED BY -
       NIDNDMHD = Pointer to the first NDMBK for the device.
       NIDNDMTL = Pointer to the last NDMBK for the device.
     CREATED BY :
                  Receipt of a message for a Network Interface Device.
     DELETED BY :
                  Delivery of a message for a Network Interface Device.

#### NDMBK Control Block Content

#### NDMBK DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      NDMBK          Network Device Message Block
         Chain pointers (maintained by the NDMBK user).
    0000    0 Address      4 NDMFPNT        Pointer to Next NDMBK
    0004    4 Address      4 NDMBPNT        Pointer to Previous NDMBK
         Static attributes (maintained by the support routines).
    0008    8 Bitstring    1 NDMATTR        Message Attributes
              1... ....      NDMALLOC       X'80' - Storage was allocated
              .1.. ....      NDMFRAME       X'40' - Allocated a 4K frame
              ..1. ....      NDMPRIME       X'20' - This is a PRIMARY NDMBK
              ...1 ....      NDMCLONE       X'10' - This is a CLONE NDMBK
    0009    9 Bitstring    1 NDMFLAGS       Message Flags
              1... ....      NDMDVHDR       X'80' - NDMBK includes Device
                                            Header
              .1.. ....      NDMXDATA       X'40' - NDMBK includes XFER Data
    000A   10 Bitstring    1 NDMDTYPE       Data type
              00000000       NDMUCDAT       0 - Unicast (nonrouter) data
              00000004       NDMRTDAT       4 - Unicast (router) data
              00000008       NDMMCDAT       8 - Multicast data
              0000000C       NDMBCDAT       12 - Broadcast data
    000B   11 Bitstring    1 NDMFLAG3       Additional Flags (local usage)
    000C   12 Address      4 NDMCHAIN       Pointer to NDMBK fragment chain
         Message-specific area (NDMSPEC).
    0010   16 Signed       4 NDMSPEC (0)
         Normal message attributes.
         ******* ORG NDMSPEC Overlay for a Normal message
    0010   16 Address      4 NDMBUFAD       Pointer to Original Buffer
    0014   20 Signed       4 NDMRFCTR       Reference counter
    0018   24 Bitstring    8 NDMPARMS (0)   Message parms
                                            <length,address>
    0018   24 Signed       4 NDMBYTES       Length of message in bytes
    001C   28 Address      4 NDMDATA        Pointer to message data
         Cloned message (referencing a Primary message).
    0010   16 Address      4 NDMORIG        Pointer to Primary NDMBK
    0014   20 Bitstring    4 *              Reserved
    0018   24 Signed       4 *              (NDMBYTES) Length of message in
                                            bytes
    001C   28 Address      4 *              (NDMDATA) Pointer to message data
         End of NDMBK structure.
    0020   32 Bitstring    1 NDM$END (0)    End of NDMBK
              00000020       NDMBKLN        *-NDMBK Length of NICBK in bytes
              00000004       NDMBKSZ        (*-NDMBK+7)/8 Size of NICBK in
                                            doublewords

#### NDMBK Storage Layout

    *** NDMBK - Network Device Message Block
    *
    *     +---------------------------+---------------------------+
    *   0 |         NDMFPNT           |         NDMBPNT           |
    *     +------+------+------+------+---------------------------+
    *   8 |:ATTR |:FLAGS|:DTYPE|:FLAG3|         NDMCHAIN          |
    *     +------+------+------+------+---------------------------+
    *  10 |         NDMBUFAD          |         NDMRFCTR          |
    *     +---------------------------+---------------------------+
    *  18 |         NDMBYTES          |         NDMDATA           |
    *     +---------------------------+---------------------------+
    *  20
    *
    *** NDMBK - Network Device Message Block

    *** Overlay for NDMSPEC in NDMBK
    *
    *     +---------------------------+---------------------------+
    *  10 |         NDMORIG           |///////////////////////////|
    *     +---------------------------+---------------------------+
    *  18 |///////////////////////////|///////////////////////////|
    *     +---------------------------+---------------------------+
    *
    *** Overlay for NDMSPEC in NDMBK

#### NDMBK Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    NDM$END        0020
    NDMALLOC       0008 80
    NDMATTR        0008
    NDMBCDAT       000A 0000000C
    NDMBKLN        0020 00000020
    NDMBKSZ        0020 00000004
    NDMBPNT        0004
    NDMBUFAD       0010
    NDMBYTES       0018
    NDMCHAIN       000C
    NDMCLONE       0008 10
    NDMDATA        001C
    NDMDTYPE       000A
    NDMDVHDR       0009 80
    NDMFLAGS       0009
    NDMFLAG3       000B
    NDMFPNT        0000
    NDMFRAME       0008 40
    NDMMCDAT       000A 00000008
    NDMORIG        0010
    NDMPARMS       0018
    NDMPRIME       0008 20
    NDMRFCTR       0014
    NDMRTDAT       000A 00000004
    NDMSPEC        0010
    NDMUCDAT       000A 00000000
    NDMXDATA       0009 40

This information is based on z/VM V4R3.0. Last updated on 30 Apr 2002 at 17:01:09 EDT.
Copyright IBM Corporation, 1990, 2002