text: imp(4p) [bsd man page]
  IMP(4P) IMP(4P) NAME
  imp - IMP raw socket interface SYNOPSIS
  #include <sys/socket.h> #include <netinet/in.h> #include <netimp/if_imp.h> s = socket(AF_IMPLINK, SOCK_RAW, proto); DESCRIPTION
  The raw imp socket provides direct access to the imp(4) 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 destina- tion 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(4N), inet(4F), imp(4) 4.2 Berkeley Distribution May 16, 1986 IMP(4P)
  udp(4p) udp(4p) Name udp - Internet User Datagram Protocol Syntax #include <sys/socket.h> #include <netinet/in.h> s = socket(AF_INET, SOCK_DGRAM, 0); Description UDP is a simple, unreliable datagram protocol that is used to support the SOCK_DGRAM abstraction for the Internet protocol family. UDP sockets are connectionless and are normally used with the and calls, though the call can also be used to fix the destination for future packets (in which case the or and or). In addition broadcast packets can be sent (assuming the underlying network supports this) by using a reserved ``broadcast address''; this address is network interface dependent. The SO_BROADCAST option must be set on the socket for broadcasting to succeed. Diagnostics A socket operation may fail with one of the following errors returned: [EISCONN] Try 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 already connected. [ENOTCONN] Try to send a datagram, but no destination address is specified, and the socket has not been connected. [ENOBUFS] The system runs out of memory for an internal data structure. [EADDRINUSE] An attempt is made to create a socket with a port that has already been allocated. [EADDRNOTAVAIL] An attempt is made to create a socket with a network address for which no network interface exists. See Also getsockopt(2), send(2), socket(2) recv(2), intro(4n), inet(4f) udp(4p)