IMP(4)                      BSD Programmer's Manual                     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 re-
     ceive 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 pack-
     ets; 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 ker-
     nel 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 al-
                      ready connected;

     [ENOTCONN]       when trying to send a datagram, but no destination ad-
                      dress is specified, and the socket hasn't been connect-
                      ed;

     [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 net-
                      work address for which no network interface exists.

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

HISTORY
     The imp driver appeared in 4.2BSD.

4.2 Berkeley Distribution       March 27, 1993                               1