1 /* 2 * Copyright (c) 1986 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18 #ifndef lint 19 char copyright[] = 20 "@(#) Copyright (c) 1986 The Regents of the University of California.\n\ 21 All rights reserved.\n"; 22 #endif /* not lint */ 23 24 #ifndef lint 25 static char sccsid[] = "@(#)dgramsend.c 6.3 (Berkeley) 03/07/89"; 26 #endif /* not lint */ 27 28 #include <sys/types.h> 29 #include <sys/socket.h> 30 #include <netinet/in.h> 31 #include <netdb.h> 32 #include <stdio.h> 33 34 #define DATA "The sea is calm tonight, the tide is full . . ." 35 36 /* 37 * Here I send a datagram to a receiver whose name I get from the command 38 * line arguments. The form of the command line is dgramsend hostname 39 * portnumber 40 */ 41 42 main(argc, argv) 43 int argc; 44 char *argv[]; 45 { 46 int sock; 47 struct sockaddr_in name; 48 struct hostent *hp, *gethostbyname(); 49 50 /* Create socket on which to send. */ 51 sock = socket(AF_INET, SOCK_DGRAM, 0); 52 if (sock < 0) { 53 perror("opening datagram socket"); 54 exit(1); 55 } 56 /* 57 * Construct name, with no wildcards, of the socket to send to. 58 * Getnostbyname() returns a structure including the network address 59 * of the specified host. The port number is taken from the command 60 * line. 61 */ 62 hp = gethostbyname(argv[1]); 63 if (hp == 0) { 64 fprintf(stderr, "%s: unknown host\n", argv[1]); 65 exit(2); 66 } 67 bcopy(hp->h_addr, &name.sin_addr, hp->h_length); 68 name.sin_family = AF_INET; 69 name.sin_port = htons(atoi(argv[2])); 70 /* Send message. */ 71 if (sendto(sock, DATA, sizeof(DATA), 0, &name, sizeof(name)) < 0) 72 perror("sending datagram message"); 73 close(sock); 74 } 75