NAME

rmp — HP Remote Maintenance Protocol Family

SYNOPSIS

options RMP
#include <sys/types.h>
#include <sys/socket.h>
#include <netrmp/rmp.h>
#include <netrmp/rmp_var.h>

int
socket(AF_RMP, SOCK_RAW, proto);

DESCRIPTION

Hewlett-Packard's Remote Maintenance Protocol family is a collection of protocols layered atop IEEE 802.3. The current implementation of the RMP family provides protocol support only for the SOCK_RAW socket type. As a result, sendto(2) and recvfrom(2) must be used to send and receive RMP packets.

The format of an RMP packet is defined in the include file <netrmp/rmp_var.h>. The RMP packet arrives encapsulated in an (HP extended) IEEE 802.2 packet. The IEEE 802.2 packet is preceded by the kernel address of an ifnet struct which is used to `route' a packet out the same interface it arrived on. Outgoing packets are encapsulated in a standard IEEE 802.3 packet, while incoming packets have this information stripped away.

ADDRESSING

RMP (IEEE 802.3) addresses are 6 octets in length (48 bytes). Sockets in the Remote Maintenance Protocol family use the following addressing structure:

struct sockaddr_rmp { 
	short		srmp_family; 
	u_char		srmp_dhost[6]; 
};

PROTOCOLS

The RMP protocol family supported by the operating system currently consists of the Boot Protocol (proto=RMPPROTO_BOOT). Unfortunately, we have no documentation on the Remote Maintenance Protocol and only sketchy information about the Boot Protocol.

SEE ALSO

bind(2), recvfrom(2), sendto(2), socket(2), intro(4), rbootd(8)

Stuart Sechrest, An Introductory 4.4BSD Interprocess Communication Tutorial. (see /usr/share/doc/psd/20.ipctut)

Samuel J. Leffler, Robert S. Fabry, William N. Joy, Phil Lapsley, Steve Miller, and Chris Torek, Advanced 4.4BSD IPC Tutorial. (see /usr/share/doc/psd/21.ipc)

HISTORY

The rmp protocol interface currently under development.

BUGS

• The HP ROM uses IEEE 802.3 (as opposed to Ethernet) packets. While the kernel heuristically recognizes these packets, a more general mechanism for doing so should be provided.
• The HP ROM uses a multicast address when first trying to locate boot servers. While the Ethernet [sic] board is programmed to recognize this particular multicast address (9:0:9:0:0:4), a more general mechanism for doing so should be provided.
• The kernel supports only RAW sockets for the RMP protocol. This is either a bug or a feature, since the kernel is smaller at the price of greater complexity in the server.
• There is no support for bind(2)'ing an address in the RMP domain. Something like an RMPADDR_ANY should be provided to prevent more than one rbootd(8) server from running at the same time.