DLPI Programmer's Guide

142 Chapter 2
DLPI Primitives
DLPI States
• A DL_DATA_REQ primitive received by the DLS provider in the
state DL_PROV_RESET_PENDING (i.e. after a DL_RESET_IND has
been passed to the DLS user) or the state DL_IDLE (i.e. after a data
link connection has been released) should be discarded by the DLS
provider.
• A DL_DATA_IND primitive received by the DLS user after the user
has issued a DL_RESET_REQ should be discarded.
To ensure accurate processing of DLPI primitives, the DLS provider
must adhere to the following rules concerning the receipt and generation
of STREAMS M_FLUSH messages during various state transitions.
• The DLS provider must be ready to receive M_FLUSH messages from
upstream and flush its queues as specified in the message.
• The DLS provider must issue an M_FLUSH message upstream to
flush both the read and write queues after receiving a successful
DL_UNBIND_REQ primitive but before issuing the DL_OK_ACK.
• If an incoming disconnect occurs when the interface is in the
DL_DATAXFER, DL_USER_RESET_PENDING, or
DL_PROV_RESET_PENDING state, the DLS provider must send up
an M_FLUSH message to flush both the read and write queues before
sending up a DL_DISCONNECT_IND.
• If a DL_DISCONNECT_REQ is issued in the DL_DATAXFER,
DL_USER_RESET_PENDING, or DL_PROV_RESET_PENDING
states, the DLS provider must issue an M_FLUSH message upstream
to flush both the read and write queues after receiving the successful
DL_DISCONNECT_REQ but before issuing the DL_OK_ACK.
• If a reset occurs when the interface is in the DL_DATAXFER or
DL_USER_RESET_PENDING state, the DLS provider must send up
an M_FLUSH message to flush both the read and write queues before
sending up a DL_RESET_IND or DL_RESET_CON.