The le driver is a "style 2" Data Link Service provider. All M_PROTO and M_PCPROTO
type messages are interpreted as DLPI primitives. Valid DLPI primitives are defined in <sys/dlpi.h>. Refer
to dlpi(7P) for more information. 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 data type 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 device is initialized on first attach and de-initialized (stopped) on last detach.
The values returned by the driver in the DL_INFO_ACK primitive in response to the DL_INFO_REQ from the user are
as follows:
- The maximum SDU is 1500 (ETHERMTU - defined in <sys/ethernet.h>).
- The minimum SDU is 0.
- The dlsap address length is 8.
- The MAC type is DL_ETHER.
- The sap length value is -2 meaning the physical address component is followed immediately by a 2 byte sap component
within the DLSAP address.
- The service mode is DL_CLDLS.
- No optional quality of service (QOS) support is included at present so the QOS fields are 0.
- The provider style is DL_STYLE2.
- The version is DL_VERSION_2.
- The broadcast address value is Ethernet/IEEE broadcast address (0xFFFFFF).
Once in the DL_ATTACHED state, the user must send a DL_BIND_REQ to associate a particular SAP (Service Access Pointer) with the stream. The le driver interprets the sap field within the DL_BIND_REQ as an
Ethernet "type" therefore valid values for the sap field are in the [0-0xFFFF] range. Only one Ethernet type can be bound to the stream
at any time.
If the user selects a sap with a value of 0, the receiver will be in "802.3 mode". All frames received from the media having a "type"
field in the range [0-1500] are assumed to be 802.3 frames and are routed up all open Streams which are bound to sap value 0.
If more than one Stream is in "802.3 mode" then the frame will be duplicated and routed up multiple Streams as DL_UNITDATA_IND messages.
In transmission, the driver checks the sap field of the DL_BIND_REQ if the sap value is 0, and if
the destination type field is in the range [0-1500]. If either is true, the driver computes the length of the message, not including initial M_PROTO mblk (message block), of all subsequent DL_UNITDATA_REQ messages and transmits 802.3 frames that have this value in the MAC frame header length
field.
The le driver DLSAP address format consists of the 6 byte physical (Ethernet) address component followed immediately by the 2 byte sap (type) component producing an 8 byte DLSAP address. Applications should not hardcode to this particular implementation-specific DLSAP address format but use information returned in the DL_INFO_ACK primitive 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 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 Ethernet by sending DL_UNITDATA_REQ messages to
the le driver. The le driver will route received Ethernet frames up all those open and bound streams having a sap which matches the Ethernet type
as DL_UNITDATA_IND messages. Received Ethernet 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 primitives.
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