IMP(4)

NAME
imp - IMP raw socket interface

SYNOPSIS
#include <sys/socket.h>
#include <netinet/in.h>
#include <netimp/if_imp.h>
int
socket(AF_IMPLINK, SOCK_RAW, proto);

DESCRIPTION
The raw imp socket provides direct access to the imp network interface. Users send packets through the interface using the send(2) calls, and receive packets with the recv(2), calls. All outgoing packets must have an 1822 96-bit leader on the front. Likewise, packets received by the user will have this leader on the front. The 1822 leader and the legal values for the various fields are defined in the include file <netimp/if_imp.h>. The raw imp interface automatically installs the length and destination address in the 1822 leader of all outgoing packets; these need not be filled in by the user.

If the protocol selected, proto, is zero, the socket will receive all IMP messages except RFNM and incompletes which are not input data for a kernel protocol. If proto is non-zero, only messages for the specified link type will be received.

DIAGNOSTICS
An operation on a socket may fail with one of the following errors:

[EISCONN]
    when trying to establish a connection on a socket which already has one, or when trying to send a datagram with the destination address specified and the socket is already connected;

[ENOTCONN]
    when trying to send a datagram, but no destination address is specified, and the socket hasn't been connected;

[ENOBUFS]
    when the system runs out of memory for an internal data structure;

[ENOBUFS]
    eight messages to the destination host are outstanding, and another eight are already queued for output;

[EADDRNOTAVAIL]
    when an attempt is made to create a socket with a network address for which no network interface exists.

SEE ALSO
intro(4), inet(4), imp(4)

HISTORY
The imp driver appeared in 4.2BSD.