131 lines
4.8 KiB
HTML
131 lines
4.8 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html lang="en-us" xml:lang="en-us">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="security" content="public" />
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<meta name="Robots" content="index,follow" />
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<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
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<meta name="DC.Type" content="reference" />
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<meta name="DC.Title" content="Example: Receive multicast datagrams" />
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<meta name="abstract" content="This example enables a socket to receive multicast datagrams." />
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<meta name="description" content="This example enables a socket to receive multicast datagrams." />
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<meta name="DC.Relation" scheme="URI" content="xmulticast.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2001, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2001, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="x2multicast" />
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<meta name="DC.Language" content="en-us" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Example: Receive multicast datagrams </title>
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</head>
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<body id="x2multicast"><a name="x2multicast"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Example: Receive multicast datagrams </h1>
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<div><p>This example enables a socket to receive multicast datagrams.</p>
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<div class="section"><div class="note"><span class="notetitle">Note:</span> By using the code examples, you agree to the terms of the <a href="codedisclaimer.htm">Code license and disclaimer information</a>.</div>
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<pre>#include <sys/types.h>
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#include <sys/socket.h>
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#include <arpa/inet.h>
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#include <netinet/in.h>
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#include <stdio.h>
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#include <stdlib.h>
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struct sockaddr_in localSock;
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struct ip_mreq group;
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int sd;
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int datalen;
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char databuf[1024];
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int main (int argc, char *argv[])
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{
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/* ------------------------------------------------------------*/
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/* */
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/* Receive Multicast Datagram code example. */
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/* */
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/* ------------------------------------------------------------*/
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/*
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* Create a datagram socket on which to receive.
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*/
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sd = socket(AF_INET, SOCK_DGRAM, 0);
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if (sd < 0) {
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perror("opening datagram socket");
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exit(1);
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}
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/*
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* Enable SO_REUSEADDR to allow multiple instances of this
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* application to receive copies of the multicast datagrams.
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*/
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{
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int reuse=1;
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if (setsockopt(sd, SOL_SOCKET, SO_REUSEADDR,
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(char *)&reuse, sizeof(reuse)) < 0) {
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perror("setting SO_REUSEADDR");
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close(sd);
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exit(1);
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}
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}
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/*
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* Bind to the proper port number with the IP address
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* specified as INADDR_ANY.
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*/
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memset((char *) &localSock, 0, sizeof(localSock));
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localSock.sin_family = AF_INET;
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localSock.sin_port = htons(5555);;
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localSock.sin_addr.s_addr = INADDR_ANY;
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if (bind(sd, (struct sockaddr*)&localSock, sizeof(localSock))) {
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perror("binding datagram socket");
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close(sd);
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exit(1);
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}
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/*
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* Join the multicast group 225.1.1.1 on the local 9.5.1.1
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* interface. Note that this IP_ADD_MEMBERSHIP option must be
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* called for each local interface over which the multicast
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* datagrams are to be received.
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*/
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group.imr_multiaddr.s_addr = inet_addr("225.1.1.1");
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group.imr_interface.s_addr = inet_addr("9.5.1.1");
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if (setsockopt(sd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
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(char *)&group, sizeof(group)) < 0) {
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perror("adding multicast group");
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close(sd);
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exit(1);
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}
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/*
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* Read from the socket.
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*/
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datalen = sizeof(databuf);
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if (read(sd, databuf, datalen) < 0) {
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perror("reading datagram message");
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close(sd);
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exit(1);
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}
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}</pre>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="xmulticast.htm" title="IP multicasting provides the capability for an application to send a single IP datagram that a group of hosts in a network can receive.">Examples: Use multicasting with AF_INET</a></div>
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</div>
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</div>
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</body>
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</html>
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