ICMP(7P)							      ICMP(7P)

NAME    [Toc]    [Back]

     icmp - Internet Control Message Protocol

SYNOPSIS    [Toc]    [Back]

     #include <sys/socket.h>
     #include <netinet/in.h>

     s = socket(AF_INET, SOCK_RAW, proto);

DESCRIPTION    [Toc]    [Back]

     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    [Toc]    [Back]

     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 ALSO    [Toc]    [Back]

     send(2), recv(2), intro(3), inet(7F), ip(7P)


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