.\" Copyright (c) 1990, 1991 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the Systems Programming Group of the University of Utah Computer
.\" Science Department.
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     from: @(#)rmp.4	5.2 (Berkeley) 3/27/91
.\"	$NetBSD: rmp.4,v 1.13 2022/06/28 20:12:52 rillig Exp $
.\"
.Dd June 28, 2022
.Dt RMP 4 hp300
.Os
.Sh NAME
.Nm rmp
.Nd
.Tn HP
Remote Maintenance Protocol Family
.Sh SYNOPSIS
.Cd "options RMP"
.In sys/types.h
.In sys/socket.h
.In netrmp/rmp.h
.In 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
.In 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
currently consists 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 hp300/intro 4 ,
.Xr rbootd 8
.Rs
.%T "An Introductory 4.4BSD Interprocess Communication Tutorial"
.%A Stuart Sechrest
.Re
.Pq see Pa /usr/share/doc/reference/ref3/sockets
.Rs
.%T "Advanced 4.4BSD IPC Tutorial"
.%A Samuel J. Leffler
.%A Robert S. Fabry
.%A William N. Joy
.%A Phil Lapsley
.%A Steve Miller
.%A Chris Torek
.Re
.Pq see Pa /usr/share/doc/reference/ref3/sockets-advanced
.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 2 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 8
server from running at the same time.
.El