llc1(7D)
NAME
llc1 - Logical Link Control Protocol Class 1 Driver
SYNOPSIS
#include <sys/stropts.h>
#include <sys/ethernet.h>
#include <sys/dlpi.h>
#include <sys/llc1.h>
DESCRIPTION
The llc1 driver is a multi-threaded, loadable, clonable,
STREAMS multiplexing driver supporting the connectionless
Data Link Provider Interface, dlpi(7P), implementing IEEE
802.2 Logical Link Control Protocol Class 1 over a STREAM to
a MAC level driver. Multiple MAC level interfaces installed
within the system can be supported by the driver. The llc1
driver provides basic support for the LLC1 protocol. Func-
tions provided include frame transmit and receive, XID, and
TEST, multicast support, and error recovery and reporting.
The cloning, character-special device, /dev/llc1, is used to
access all LLC1 controllers configured under llc1.
The llc1 driver is a "Style 2" Data Link Service provider.
All messages of types M_PROTO and M_PCPROTO are interpreted
as DLPI primitives. An explicit DL_ATTACH_REQ message by
the user is required to associate the opened stream with a
particular device (ppa). The ppa ID is interpreted as an
unsigned long and indicates the corresponding device
instance (unit) number. An error (DL_ERROR_ACK) is returned
by the driver if the ppa field value does not correspond to
a valid device instance number for this system.
The values returned by the driver in the DL_INFO_ACK primi-
tive in response to the DL_INFO_REQ from the user are as
follows:
o The maximum Service Data UNIT (SDU) is derived from
the MAC layer linked below the driver. In the case of
an Ethernet driver, the SDU will be 1497.
o The minimum SDU is 0.
o The MAC type is DL_CSMACD or DL_TPR as determined by
the driver linked under llc1. If the driver reports
that it is DL_ETHER, it will be changed to DL_CSMACD;
otherwise the type is the same as the MAC type.
o The sap length value is -1, meaning the physical
address component is followed immediately by a 1-octet
sap component within the DLSAP address.
o The service mode is DL_CLDLS.
o The MAC type is DL_CSMACD or DL_TPR as determined by
the driver linked under llc1. If the driver reports
that it is DL_ETHER, it will be changed to DL_CSMACD;
otherwise the type is the same as the MAC type.
o The dlsap address length is 7.
o No optional quality of service (QOS) support is
included at present, so the QOS fields should be ini-
tialized to 0.
o The DLPI version is DL_VERSION_2.
o The provider style is DL_STYLE2.
o The broadcast address value is the broadcast address
returned from the lower level driver.
Once in the DL_ATTACHED state, the user must send a
DL_BIND_REQ to associate a particular Service Access Point
(SAP) with the stream. The llc1 driver interprets the sap
field within the DL_BIND_REQ as an IEEE 802.2 "SAP," there-
fore valid values for the sap field are in the [0-0xFF]
range with only even values being legal.
The llc1 driver DLSAP address format consists of the 6-
octet physical (e.g., Ethernet) address component followed
immediately by the 1-octet sap (type) component producing a
7-octet DLSAP address. Applications should not hard-code to
this particular implementation-specific DLSAP address for-
mat, but use information returned in the DL_INFO_ACK primi-
tive to compose and decompose DLSAP addresses. The sap
length, full DLSAP length, and sap/physical ordering are
included within the DL_INFO_ACK. The physical address
length can be computed by subtracting the absolute value of
the sap length from the full DLSAP address length or by
issuing the DL_PHYS_ADDR_REQ to obtain the current physical
address associated with the stream.
Once in the DL_BOUND state, the user may transmit frames on
the LAN by sending DL_UNITDATA_REQ messages to the llc1
driver. The llc1 driver will route received frames up all
open and bound streams having a sap which matches the IEEE
802.2 DSAP as DL_UNITDATA_IND messages. Received frames are
duplicated and routed up multiple open streams if necessary.
The DLSAP address contained within the DL_UNITDATA_REQ and
DL_UNITDATA_IND messages consists of both the sap (type) and
physical (Ethernet) components.
In addition to the mandatory, connectionless DLPI message
set, the driver additionally supports the following primi-
tives:
The DL_ENABMULTI_REQ and DL_DISABMULTI_REQ primitives
enable/disable reception of specific multicast group
addresses. A set of multicast addresses may be iteratively
created and modified on a per-stream basis using these prim-
itives. These primitives are accepted by the driver in any
driver state that is valid while still being attached to the
ppa.
The DL_PHYS_ADDR_REQ primitive returns the 6-octet physical
address currently associated (attached) to the stream in the
DL_PHYS_ADDR_ACK primitive. This primitive is valid only in
states following a successful DL_ATTACH_REQ.
The DL_SET_PHYS_ADDR_REQ primitive changes the 6-octet phy-
sical address currently associated (attached) to this
stream. Once changed, all streams subsequently opened and
attached to this device will obtain this new physical
address. Once changed, the physical address will remain set
until this primitive is used to change the physical address
again or the system is rebooted, whichever occurs first.
The DL_XID_REQ/DL_TEST_REQ primitives provide the means for
a user to issue an LLC XID or TEST request message. A
response to one of these messages will be in the form of a
DL_XID_CON/DL_TEST_CON message.
The DL_XID_RES/DL_TEST_RES primitives provide a way for the
user to respond to the receipt of an XID or TEST message
that was received as a DL_XID_IND/DL_TEST_IND message.
XID and TEST will be automatically processed by llc1 if the
DL_AUTO_XID/DL_AUTO_TEST bits are set in the DL_BIND_REQ.
FILES
/dev/llc1
cloning, character-special device
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Architecture | x86 |
|_____________________________|_____________________________|
SEE ALSO
attributes(5), dlpi(7P)
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