ETH

NAME

ETH (Ethernet Protocol)

SYNOPSIS

This hardware-independent protocol provides the interface between the rest of the x-kernel protocols and the actual ethernet drivers. It has a UPI interface to protocols above it and interacts with the drivers through a specialized UPI interface. There should be a separate instantiation of the ETH protocol for each driver protocol.

REALM

ETH is in the ASYNC realm.

PARTICIPANTS

ETH expects a single remote participant with an ETHhost pointer on the top of the stack. If the local participant is present it is ignored.

CONTROL OPERATIONS

ETH_SETPROMISCUOUS:

Sets the corresponding device controller in promiscuous mode and deliver copies of all packets to this session. (session only)

Input:

none

Output:

none

EXTERNAL INTERFACE

Ethernet driver protocols should include the file protocols/eth/eth_i.h which defines the interface between ETH and the drivers.

ETH will openenable its driver protocol once at initialization time, without a participant list. This gives the driver protocol the XObj it should use in xDemux when it delivers messages.

ETH calls xPush with the driver protocol object (not a session) to send a message. ETH never opens the lower protocol.

ETH will attach a pointer to an ETHhdr as a message attribute for each outgoing message:

        typedef struct {
            ETHhost     dst;
            ETHhost     src;
            u_short     type;
        } ETHhdr;

ETH requires that the driver attach a message attribute pointing to an appropriate ETHhdr structure for every incoming message. For both incoming and outgoing messages, the ETHhdr type field will be in network byte order.

ETH requires the driver protocol to implement the control op GETMYHOST.

ETH provides support for IEEE 802.3 packet formats. An upper protocol registering with Ethernet type 0 is assumed to the recipient for all IEEE 802.3 packets. Conversely, a protocol using an Ethernet type smaller than the maximum IEEE 802.3 data size will have its packets sent using IEEE 802.3 format (i.e., with the packet length overwriting the type field.)

CONFIGURATION

Each instantiation of ETH should be configured above its corresponding driver protocol.

ETH recognizes the following ROM options:

eth/xxx mtu N: Instantiation xxx of ETH should use an MTU of N (decimal). Default is 1500.

AUTHOR

Ed Menze