iSCSI - E.3.2. 개시자 알고리즘

E.3.2. Initiator Algorithms
E.3.2. 이니시에이터 알고리즘
Recover-Status-if-Possible(Connection, CurrentPDU)
{
  if ((Connection.state == LOGGED_IN) and
                 connection is not already considered failed) {
     if (operational ErrorRecoveryLevel > 0) {
        if (# of missing PDUs is trackable) {
              Note the missing StatSNs in Connection
             that were not already requested with SNACK;
          Build-And-Send-SSnack(Connection);
            } else {
              Connection.PerformConnectionCleanup = TRUE;
        }
     } else {
            Connection.PerformConnectionCleanup = TRUE;
     }
     if (Connection.PerformConnectionCleanup == TRUE) {
        Start-Timer(Connection-Cleanup-Handler, Connection, 0);
         }
  }
}

Retransmit-Command-if-Possible(Connection, CmdSN)
{

  if (operational ErrorRecoveryLevel > 0) {
     Retrieve the InitiatorTaskTag, and thus TCB for the CmdSN.
     Build-And-Send-Command(Connection, TCB);
  }
}

Evaluate-a-StatSN(Connection, CurrentPDU)
{
  send-status-SNACK = FALSE;
  if (Connection.SoFarInOrder == TRUE) {
     if (current StatSN is the expected) {
          Increment Connection.ExpectedStatSN.
     } else {
              Connection.SoFarInOrder = FALSE;
              send-status-SNACK = TRUE;
         }
  } else {
     if (current StatSN was considered missing) {
          remove current StatSN from the missing list.
     } else {
              if (current StatSN is higher than expected){
                  send-status-SNACK = TRUE;

              } else {
                  send-status-SNACK = FALSE;
              discard the PDU;
          }
     }
     Adjust Connection.ExpectedStatSN if appropriate.
     if (missing StatSN list is empty) {
          Connection.SoFarInOrder = TRUE;
         }
  }
  return send-status-SNACK;
}

Receive-a-In-PDU(Connection, CurrentPDU)
{
  check-basic-validity(CurrentPDU);
  if (Header-Digest-Bad) discard, return;
  Retrieve TCB for CurrentPDU.InitiatorTaskTag.
  if (CurrentPDU.type == Nop-In) {
        if (the PDU is unsolicited) {
              if (current StatSN is not expected) {
                   Recover-Status-if-Possible(Connection,
                                CurrentPDU);
              }
              if (current ExpCmdSN is not Session.CmdSN) {
                  Retransmit-Command-if-Possible(Connection,
                                CurrentPDU.ExpCmdSN);
              }
        }
  } else if (CurrentPDU.type == Reject) {
        if (it is a data digest error on immediate data) {
              Retransmit-Command-if-Possible(Connection,
                                 CurrentPDU.BadPDUHeader.CmdSN);
        }
  } else if (CurrentPDU.type == Response) {
       send-status-SNACK = Evaluate-a-StatSN(Connection,
                                      CurrentPDU);
       if (send-status-SNACK == TRUE)
           Recover-Status-if-Possible(Connection, CurrentPDU);
  } else { /* REST UNRELATED TO WITHIN-CONNECTION-RECOVERY,
            * NOT SHOWN */
  }
}

Command-Acknowledge-Timeout-Handler(TCB)
{
  Retrieve the Connection for TCB.
  Retransmit-Command-if-Possible(Connection, TCB.CmdSN);

}

Status-Expect-Timeout-Handler(Connection)
{
  if (operational ErrorRecoveryLevel > 0) {
      Build-And-Send-Nop-Out(Connection);
  } else if (InitiatorProactiveSNACKEnabled){
      if ((Connection.state == LOGGED_IN) and
             connection is not already considered failed) {
           Build-And-Send-SSnack(Connection);
      }
  }
}