IGMP(4) BSD Programmer's Manual IGMP(4)NAMEigmp - Internet Control Message Protocol
SYNOPSIS
#include <sys/socket.h>
#include <netinet/in.h>
int
socket(AF_INET, SOCK_RAW, proto);
DESCRIPTION
IGMP is the multicast group management protocol used to support multicas-
ting for IP and the Internet protocol family. It may be accessed through
a ``raw socket'' for IP multicast monitoring and diagnostic functions.
The proto parameter to the socket call to create an IGMP socket is ob-
tained from getprotobyname(3). IGMP 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) unless IP_HDRINCL option has been specified.
Incoming packets are received with the IP header and options intact.
SYSCTL VARIABLES
Some IGMP options can be read or written via the sysctl(3) facility.
Variables specific to IGMP are:
CTL_NET, PF_INET, IPPROTO_IGMP
These variables are used to get or set various global ICMP options.
Fourth level name Type Changeable
IGMPCTL_STATS struct no
IGMPCTL_STATS
Returns the struct igmpstat containing statistics on the process-
ing of IGMP packets.
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 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;
[EADDRNOTAVAIL] when an attempt is made to create a socket with a net-
work address for which no network interface exists.
SEE ALSOsend(2), recv(2), sysctl(3), intro(4), inet(4), ip(4)4.3 Berkeley Distribution June 5, 1993 1