84 lines
3.0 KiB
C
84 lines
3.0 KiB
C
.\" Copyright (c) 1986, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)dgramread.c 8.1 (Berkeley) 6/8/93
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.\"
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <stdio.h>
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/*
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* In the included file <netinet/in.h> a sockaddr_in is defined as follows:
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* struct sockaddr_in {
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* short sin_family;
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* u_short sin_port;
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* struct in_addr sin_addr;
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* char sin_zero[8];
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* };
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*
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* This program creates a datagram socket, binds a name to it, then reads
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* from the socket.
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*/
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main()
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{
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int sock, length;
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struct sockaddr_in name;
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char buf[1024];
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/* Create socket from which to read. */
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sock = socket(AF_INET, SOCK_DGRAM, 0);
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if (sock < 0) {
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perror("opening datagram socket");
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exit(1);
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}
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/* Create name with wildcards. */
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name.sin_family = AF_INET;
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name.sin_addr.s_addr = INADDR_ANY;
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name.sin_port = 0;
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if (bind(sock, &name, sizeof(name))) {
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perror("binding datagram socket");
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exit(1);
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}
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/* Find assigned port value and print it out. */
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length = sizeof(name);
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if (getsockname(sock, &name, &length)) {
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perror("getting socket name");
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exit(1);
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}
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printf("Socket has port #%d\en", ntohs(name.sin_port));
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/* Read from the socket */
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if (read(sock, buf, 1024) < 0)
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perror("receiving datagram packet");
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printf("-->%s\en", buf);
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close(sock);
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}
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