.\"	$OpenBSD: rmp.4,v 1.3 2000/03/02 14:46:46 todd Exp $
.\" Copyright (c) 1990, 1991 The Regents of the University of California.
.\" All rights reserved.
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.\" This code is derived from software contributed to Berkeley by
.\" the Systems Programming Group of the University of Utah Computer
.\" Science Department.
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.\"     from: @(#)rmp.4	5.2 (Berkeley) 3/27/91
.\"
.Dd March 27, 1991
.Dt RMP 4 hp300
.Os
.Sh NAME
.Nm rmp
.Nd
.Tn HP
Remote Maintenance Protocol Family
.Sh SYNOPSIS
.Cd "options RMP"
.Fd #include <sys/types.h>
.Fd #include <sys/socket.h>
.Fd #include <netrmp/rmp.h>
.Fd #include <netrmp/rmp_var.h>
.Ft int
.Fn socket AF_RMP SOCK_RAW proto
.Sh DESCRIPTION
Hewlett-Packard's Remote Maintenance Protocol family is a collection
of protocols layered atop
.Tn IEEE  802.3 .
The current implementation of the RMP family provides protocol support only
for the
.Dv SOCK_RAW
socket type.
As a result,
.Xr sendto 2
and
.Xr recvfrom 2
must be used to send and
receive
.Tn RMP
packets.
.Pp
The format of an
.Tn RMP
packet is defined in the include file
.Aq Pa netrmp/rmp_var.h .
The
.Tn RMP
packet arrives encapsulated in an
.Pf ( Tn HP
extended)
.Tn IEEE  802.2
packet.
The
.Tn IEEE  802.2
packet
is preceded by the kernel address of an
.Ar ifnet struct
which is used to `route' a packet out the same interface it
arrived on.
Outgoing packets are encapsulated in a standard
.Tn IEEE  802.3
packet, while incoming packets have this information stripped away.
.Sh ADDRESSING
.Tn RMP
.Pf ( Tn IEEE
802.3) addresses are 6 octets in length (48 bytes).
Sockets in the Remote Maintenance Protocol family use the following
addressing structure:
.Bd -literal -offset indent
struct sockaddr_rmp {
	short		srmp_family;
	u_char		srmp_dhost[6];
};
.Ed
.Sh PROTOCOLS
The
.Tn RMP
protocol family supported by the operating system
is currently comprised of the Boot Protocol
.Pq Em proto= Ns Dv RMPPROTO_BOOT .
Unfortunately, we have no documentation on the Remote Maintenance
Protocol and only sketchy information about the Boot Protocol.
.Sh SEE ALSO
.Xr bind 2 ,
.Xr recvfrom 2 ,
.Xr sendto 2 ,
.Xr socket 2 ,
.Xr intro 4 ,
.Xr rbootd 8
.Rs
.%T "An Advanced 4.3 BSD Interprocess Communication Tutorial"
.Re
.Sh HISTORY
The
.Nm
protocol interface
.Ud
.Sh BUGS
.Bl -bullet
.It
The
.Tn HP ROM
uses
.Tn 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.
.It
The
.Tn 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.
.It
The kernel supports only
.Tn RAW
sockets for the
.Tn RMP
protocol.
This is either a bug or a feature, since the kernel is smaller at the
price of greater complexity in the server.
.It
There is no support for
.Xr bind Ns 'ing
an address in the
.Tn RMP
domain.
Something like an
.Dv RMPADDR_ANY
should be provided to prevent more than one
.Xr rbootd
server from running at the same time.
.El