104 lines
3.5 KiB
C
104 lines
3.5 KiB
C
|
/* This file is part of the sample code and exercises
|
||
|
* used by the class "Advanced Programming in the UNIX
|
||
|
* Environment" taught by Jan Schaumann
|
||
|
* <jschauma@netmeister.org> at Stevens Institute of
|
||
|
* Technology.
|
||
|
*
|
||
|
* https://stevens.netmeister.org/631/
|
||
|
*/
|
||
|
|
||
|
/* $NetBSD: dgramsend.c,v 1.3 2003/08/07 10:30:50 agc Exp $
|
||
|
*
|
||
|
* Copyright (c) 1986, 1993
|
||
|
* The Regents of the University of California. All rights reserved.
|
||
|
*
|
||
|
* Redistribution and use in source and binary forms, with or without
|
||
|
* modification, are permitted provided that the following conditions
|
||
|
* are met:
|
||
|
* 1. Redistributions of source code must retain the above copyright
|
||
|
* notice, this list of conditions and the following disclaimer.
|
||
|
* 2. Redistributions in binary form must reproduce the above copyright
|
||
|
* notice, this list of conditions and the following disclaimer in the
|
||
|
* documentation and/or other materials provided with the distribution.
|
||
|
* 3. Neither the name of the University nor the names of its contributors
|
||
|
* may be used to endorse or promote products derived from this software
|
||
|
* without specific prior written permission.
|
||
|
*
|
||
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
||
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
||
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
||
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
||
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
||
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
||
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
||
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
||
|
* SUCH DAMAGE.
|
||
|
*
|
||
|
* @(#)dgramsend.c 8.1 (Berkeley) 6/8/93
|
||
|
*/
|
||
|
#include <sys/types.h>
|
||
|
#include <sys/socket.h>
|
||
|
#include <netinet/in.h>
|
||
|
#include <netdb.h>
|
||
|
#include <stdio.h>
|
||
|
#include <stdlib.h>
|
||
|
#include <string.h>
|
||
|
#include <unistd.h>
|
||
|
|
||
|
/* 'Dover Beach' by Matthew Arnold -- look it up. */
|
||
|
#define DATA "The sea is calm tonight, the tide is full . . ."
|
||
|
|
||
|
/*
|
||
|
* Here I send a datagram to a receiver whose name I get from the command
|
||
|
* line arguments. The form of the command line is dgramsend hostname
|
||
|
* portnumber
|
||
|
*/
|
||
|
|
||
|
int main(int argc, char **argv)
|
||
|
{
|
||
|
int sock, port;
|
||
|
struct sockaddr_in name;
|
||
|
struct hostent *hp;
|
||
|
|
||
|
memset(&name, 0, sizeof(name));
|
||
|
|
||
|
if (argc != 3) {
|
||
|
(void)printf("Usage: %s hostname port\n", argv[0]);
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
|
||
|
port = atoi(argv[2]);
|
||
|
if ((port < 1) || (port > 65536)) {
|
||
|
(void)fprintf(stderr, "Invalid port: %s\n", argv[2]);
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
|
||
|
if ((sock = socket(PF_INET, SOCK_DGRAM, 0)) < 0) {
|
||
|
perror("opening datagram socket");
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Construct name, with no wildcards, of the socket to send to.
|
||
|
* getnostbyname() returns a structure including the network address
|
||
|
* of the specified host. The port number is taken from the command
|
||
|
* line.
|
||
|
*/
|
||
|
if ((hp = gethostbyname(argv[1])) == 0) {
|
||
|
(void)fprintf(stderr, "%s: unknown host\n", argv[1]);
|
||
|
exit(EXIT_FAILURE);
|
||
|
}
|
||
|
bcopy(hp->h_addr, &name.sin_addr, hp->h_length);
|
||
|
name.sin_family = PF_INET;
|
||
|
name.sin_port = htons(port);
|
||
|
|
||
|
if (sendto(sock, DATA, sizeof(DATA), 0,
|
||
|
(struct sockaddr *)&name, sizeof(name)) < 0) {
|
||
|
perror("sending datagram message");
|
||
|
}
|
||
|
(void)close(sock);
|
||
|
return EXIT_SUCCESS;
|
||
|
}
|