ICMP(4P)ICMP(4P)NAMEicmp - Internet Control Message Protocol
SYNOPSIS
#include <sys/socket.h>
#include <netinet/in.h>
s = socket(AF_INET, SOCK_RAW, proto);
DESCRIPTION
ICMP is the error and control message protocol used by IP and the
Internet protocol family. It may be accessed through a “raw socket”
for network monitoring and diagnostic functions. The proto parameter
to the socket call to create an ICMP socket is obtained from
getprotobyname(3N). ICMP sockets are connectionless, and are normally
used with the sendto and recvfrom calls, though the connect(2) call may
also be used to fix the destination for future packets (in which case
the read(2) or recv(2) and write(2) or send(2) system calls may be
used).
Outgoing packets automatically have an IP header prepended to them
(based on the destination address). Incoming packets are received with
the IP header and options intact.
DIAGNOSTICS
A socket operation may fail with one of the following errors returned:
[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;
[EADDRNOTAVAIL]
when an attempt is made to create a socket with a
network address for which no network interface exists.
SEE ALSOsend(2), recv(2), intro(4N), inet(4F), ip(4P)4.3 Berkeley Distribution May 16, 1986 ICMP(4P)
