104 lines
3.5 KiB
C
104 lines
3.5 KiB
C
/* This file is part of the sample code and exercises
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* used by the class "Advanced Programming in the UNIX
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* Environment" taught by Jan Schaumann
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* <jschauma@netmeister.org> at Stevens Institute of
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* Technology.
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*
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* https://stevens.netmeister.org/631/
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*/
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/* $NetBSD: dgramsend.c,v 1.3 2003/08/07 10:30:50 agc Exp $
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*
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* 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. 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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* @(#)dgramsend.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 <netdb.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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/* 'Dover Beach' by Matthew Arnold -- look it up. */
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#define DATA "The sea is calm tonight, the tide is full . . ."
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/*
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* Here I send a datagram to a receiver whose name I get from the command
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* line arguments. The form of the command line is dgramsend hostname
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* portnumber
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*/
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int main(int argc, char **argv)
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{
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int sock, port;
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struct sockaddr_in name;
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struct hostent *hp;
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memset(&name, 0, sizeof(name));
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if (argc != 3) {
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(void)printf("Usage: %s hostname port\n", argv[0]);
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exit(EXIT_FAILURE);
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}
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port = atoi(argv[2]);
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if ((port < 1) || (port > 65536)) {
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(void)fprintf(stderr, "Invalid port: %s\n", argv[2]);
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exit(EXIT_FAILURE);
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}
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if ((sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
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perror("opening datagram socket");
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exit(EXIT_FAILURE);
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}
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/*
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* Construct name, with no wildcards, of the socket to send to.
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* getnostbyname() returns a structure including the network address
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* of the specified host. The port number is taken from the command
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* line.
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*/
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if ((hp = gethostbyname(argv[1])) == 0) {
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(void)fprintf(stderr, "%s: unknown host\n", argv[1]);
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exit(EXIT_FAILURE);
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}
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bcopy(hp->h_addr, &name.sin_addr, hp->h_length);
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name.sin_family = PF_INET;
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name.sin_port = htons(port);
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if (sendto(sock, DATA, sizeof(DATA), 0,
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(struct sockaddr *)&name, sizeof(name)) < 0) {
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perror("sending datagram message");
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}
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(void)close(sock);
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return EXIT_SUCCESS;
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}
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