SESBK | Back to Index page

| Prolog Control Block Contents SESBK DSECT Storage Layout Cross Reference (Contains links to field and bit definitions) |
Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

SESBK Prolog | Top of page

     NAME       : HCPSESBK
     DESCRIPTION: MPC User Session Block
     DSECT      : SESBK
     FUNCTION   : Defines a structure that represents a single
                  Multipath Channel (MPC) User session that has been
                  established on an existing MPC group.  Each session
                  represents a data connection between the adapter
                  and the ULP (Upper Layer Protocol, ie. TCP/IP).
     LOCATED BY : MPCSESFP (HCPMPCBK) Mutipath Channel Block
                  (MPC group).
     CREATED BY : This block is created by HCPMPX when a CM_ENABLE is
                  processed for a USER connection.
     DELETED BY : HCPMPXRS - during RESET, CSCH and HSCH processing or
                  a CM_DELETE primitive from session owner.
     REFERENCES : Include here the other major blocks
     SERIALIZED : MPCBK Exclusive lock
     RELOCATION CONSIDERATIONS : None
     COMPATIBILITY AND MIGRATION CONCERNS : None.

SESBK Control Block Content | Top of page

     SESBK DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SESBK          MPC User Session Block
    0000    0 Address      4 SESDATDV       Pointer DATA device array entry
    0004    4 Bitstring    1 SESSTATE       User Session State
              00000000       SESSTART       X'00' SESSTART Initial/Startup
              00000001       SESRESET       X'01' SESRESET Reset
              00000004       SESUSCON       X'04' SESUSCON USER_CONNECT
                                            complete
              00000008       SESDMACT       X'08' SESDMACT DM_ACT complete
                                            (MPC init now complete)
              0000000C       SESSRLAN       X'0C' SESSRLAN STRTLAN complete
    0005    5 Bitstring    1 SESTRANP       Transport type
              00000001       SESIP          1 SESIP Layer 3 IP datagrams
              00000002       SESETHER       2 SESETHER Layer 2 Ethernet
                                            frames
    0006    6 Bitstring    2 SESRESV        Reserved
    0008    8 Bitstring    4 SESASST        Armed IPv4 Assists for session
              .... ...1      SESASST_ARP    X'00000001' SESASST_ARP = ARP
                                            Offload
              .... ..1.      SESASST_IN_CHECKSUM
                                            X'00000002' SESASST_IN_CHECKSUM =
                                            Inbound Chec
              .... .1..      SESASST_OUT_CHECKSUM
                                            X'00000004' SESASST_OUT_CHECKSUM
                                            = Outbound Ch
              .... 1...      SESASST_IP_FRAG
                                            X'00000008' SESASST_IP_FRAG = IP
                                            Fragmentation
              ...1 ....      SESASST_BROADCAST
                                            X'00000010' SESASST_BROADCAST =
                                            Broadcast Filt
              ..1. ....      SESASST_IPV6   X'00000020' SESASST_IPV6 = IPv6
                                            Processing
              .1.. ....      SESASST_MULTICAST
                                            X'00000040' SESASST_MULTICAST =
                                            Multicast Proc
              1... ....      SESASST_IP_REASM
                                            X'00000080' SESASST_IP_REASM = IP
                                            Reassembly
              0SESASST       SESASST_ARPCACHE
                                            X'00000100' SESASST_ARPCACHE =
                                            Query ARP Cache
              0SESASST       SESASST_ARPCOUNT
                                            X'00000200' SESASST_ARPCOUNT =
                                            Query ARP Count
              0SESASST       SESASST_ADAPTERPARMS
                                            X'00000400' SESASST_ADAPTERPARMS
                                            = SETADAPTERP
              0SESASST       SESASST_NULLTAG
                                            X'00000800' SESASST_NULLTAG =
                                            VLAN (NULL tag)
              0SESASST       SESASST_PASS   X'00001000' SESASST_PASS =
                                            Passthru (Encapsula
              0SESASST       SESASST_VLAN   X'00004000' SESASST_VLAN = VLAN
                                            (full support)
              0SESASST       SESASST_QUERYARPASST
                                            X'00040000' SESASST_QUERYARPASST
                                            = Query Arp A
    000C   12 Bitstring    4 SESASST6       Armed IPv6 Assists for session
    0010   16 Bitstring    4 SESL2AST       Armed Layer 2 Assists for session
    0014   20 Bitstring    4 SESFRAME       Armed Broadcast Frames for sess.
          The SESCONTK identifies who is the owner of this USER
          session connection. The SESUSTOK is the unique session token
          that identifies this data connection.
                                      (Originator Call ID on User Setup)
    0018   24 Bitstring   12 SESCONTK       USER Connection Token + token len
    0024   36 Bitstring   12 SESUSTOK       Session Identification + token
                                            len
              00000006       SESSIZE        (*-SESBK+7)/8 size in doublewords
              00000030       SESBSIZE       SESSIZE*8 size in bytes

SESBK Storage Layout | Top of page

    *** SESBK - MPC User Session Block
    *
    *     +---------------------------+------+------+-------------+
    *   0 |         SESDATDV          |:STATE|:TRANP|  SESRESV    |
    *     +---------------------------+------+------+-------------+
    *   8 |         SESASST           |         SESASST6          |
    *     +---------------------------+---------------------------+
    *  10 |         SESL2AST          |         SESFRAME          |
    *     +---------------------------+---------------------------+
    *  18 |                       SESCONTK                        |
    *     |                           +---------------------------+
    *  20 |                           |         SESUSTOK          |
    *     +---------------------------+                           |
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  30
    *
    *** SESBK - MPC User Session Block

SESBK Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    SESASST        0008
    SESASST_ADAPTERPARMS
                   0008 0SESASST
    SESASST_ARP    0008 01
    SESASST_ARPCACHE
                   0008 0SESASST
    SESASST_ARPCOUNT
                   0008 0SESASST
    SESASST_BROADCAST
                   0008 10
    SESASST_IN_CHECKSUM
                   0008 02
    SESASST_IP_FRAG
                   0008 08
    SESASST_IP_REASM
                   0008 80
    SESASST_IPV6   0008 20
    SESASST_MULTICAST
                   0008 40
    SESASST_NULLTAG
                   0008 0SESASST
    SESASST_OUT_CHECKSUM
                   0008 04
    SESASST_PASS   0008 0SESASST
    SESASST_QUERYARPASST
                   0008 0SESASST
    SESASST_VLAN   0008 0SESASST
    SESASST6       000C
    SESBSIZE       0024 00000030
    SESCONTK       0018
    SESDATDV       0000
    SESDMACT       0004 00000008
    SESETHER       0005 00000002
    SESFRAME       0014
    SESIP          0005 00000001
    SESL2AST       0010
    SESRESET       0004 00000001
    SESRESV        0006
    SESSIZE        0024 00000006
    SESSRLAN       0004 0000000C
    SESSTART       0004 00000000
    SESSTATE       0004
    SESTRANP       0005
    SESUSCON       0004 00000004
    SESUSTOK       0024

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:30:27 EDT.
Copyright IBM Corporation, 1990, 2020