Technical Reference: Communications, Volume 1

DLC_INFO

Indicates that normal sequenced data has been received for a link station using an I-Frame Data Received routine. If buffer overflow (OFLO) is indicated, the received data has been truncated because the received data length exceeds either the maximum I-field size derived at completion of DLC_START_LS ioctl operation or the application user's buffer size.

DLC_XIDD

Indicates that exchange identification (XID) data has been received for a link station using an XID Data Received routine. If buffer overflow (OFLO) is indicated, the received XID has been truncated because the received data length exceeds either the maximum I-field size derived at DLC_START_LS completion or the application user's buffer size. If response pending (RSPP) is indicated, an XID response is required and must be provided to GDLC using a write XID as soon as possible to avoid repolling and possible termination of the remote LS.

DLC_DGRM

Indicates that a datagram has been received for an LS using a Datagram Data Received routine. If buffer overflow (OFLO) is indicated, the received data has been truncated because the received data length exceeds either the maximum I-field size derived at DLC_START_LS completion or the application user's buffer size.

DLC_NETD

Indicates that data has been received from the network for a service access point using a Network Data Received routine. This may be link-establishment data such as X.21 call-progress signals or Smartmodem command responses. It can also be data destined for the user's SAP when no link station has been started that fits the addressing of the packet received. If buffer overflow (OFLO) is indicated, the received data has been truncated because the received data length exceeds either the maximum packet size derived at DLC_ENABLE_SAP completion or the application user's buffer size.

Network data contains the entire MAC layer packet, excluding any fields stripped by the adapter such as Preamble or CRC.

DLC_OFLO

Indicates that overflow of the user data area has occurred and the data was truncated. This error does not set a u.u_error indication.

DLC_RSPP

Indicates that the XID received requires an XID response to be sent back to the remote link station.

On the application readx subroutine, this field indicates whether the user wishes to have datalink header information prefixed to the data. If this field is set to 0 (zero), the data link header is not to be copied (only the I-field is copied). If this field is set to any nonzero value, the data link header information is included in the read operation.

On the response to an application readx subroutine, this field contains the number of data link header bytes received and copied into the data link header information field.

On asynchronous receive function handlers to the kernel user, this field contains the length of the data link header within the communications memory buffer (mbuf).