RMP(4) | Device Drivers Manual (hp300) | RMP(4)

# 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), hp300/intro(4), rbootd(8)

Stuart Sechrest, An Introductory 4.4BSD Interprocess Communication Tutorial. (see /usr/share/doc/reference/ref3/sockets)

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/reference/ref3/sockets-advanced)

# 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.

June 28, 2022 | NetBSD 11.0