1*075022b3Sagc .\" $NetBSD: dgramread.c,v 1.3 2003/08/07 10:30:50 agc Exp $ 26d400d56Sperry .\" 3d9158b13Scgd .\" Copyright (c) 1986, 1993 4d9158b13Scgd .\" The Regents of the University of California. All rights reserved. 5d9158b13Scgd .\" 6d9158b13Scgd .\" Redistribution and use in source and binary forms, with or without 7d9158b13Scgd .\" modification, are permitted provided that the following conditions 8d9158b13Scgd .\" are met: 9d9158b13Scgd .\" 1. Redistributions of source code must retain the above copyright 10d9158b13Scgd .\" notice, this list of conditions and the following disclaimer. 11d9158b13Scgd .\" 2. Redistributions in binary form must reproduce the above copyright 12d9158b13Scgd .\" notice, this list of conditions and the following disclaimer in the 13d9158b13Scgd .\" documentation and/or other materials provided with the distribution. 14*075022b3Sagc .\" 3. Neither the name of the University nor the names of its contributors 15d9158b13Scgd .\" may be used to endorse or promote products derived from this software 16d9158b13Scgd .\" without specific prior written permission. 17d9158b13Scgd .\" 18d9158b13Scgd .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19d9158b13Scgd .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20d9158b13Scgd .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21d9158b13Scgd .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22d9158b13Scgd .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23d9158b13Scgd .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24d9158b13Scgd .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25d9158b13Scgd .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26d9158b13Scgd .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27d9158b13Scgd .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28d9158b13Scgd .\" SUCH DAMAGE. 29d9158b13Scgd .\" 30d9158b13Scgd .\" @(#)dgramread.c 8.1 (Berkeley) 6/8/93 31d9158b13Scgd .\" 32d9158b13Scgd #include <sys/types.h> 33d9158b13Scgd #include <sys/socket.h> 34d9158b13Scgd #include <netinet/in.h> 35d9158b13Scgd #include <stdio.h> 36d9158b13Scgd 37d9158b13Scgd /* 38d9158b13Scgd * In the included file <netinet/in.h> a sockaddr_in is defined as follows: 39d9158b13Scgd * struct sockaddr_in { 40d9158b13Scgd * short sin_family; 41d9158b13Scgd * u_short sin_port; 42d9158b13Scgd * struct in_addr sin_addr; 43d9158b13Scgd * char sin_zero[8]; 44d9158b13Scgd * }; 45d9158b13Scgd * 46d9158b13Scgd * This program creates a datagram socket, binds a name to it, then reads 47d9158b13Scgd * from the socket. 48d9158b13Scgd */ 49d9158b13Scgd main() 50d9158b13Scgd { 51d9158b13Scgd int sock, length; 52d9158b13Scgd struct sockaddr_in name; 53d9158b13Scgd char buf[1024]; 54d9158b13Scgd 55d9158b13Scgd /* Create socket from which to read. */ 56d9158b13Scgd sock = socket(AF_INET, SOCK_DGRAM, 0); 57d9158b13Scgd if (sock < 0) { 58d9158b13Scgd perror("opening datagram socket"); 59d9158b13Scgd exit(1); 60d9158b13Scgd } 61d9158b13Scgd /* Create name with wildcards. */ 62d9158b13Scgd name.sin_family = AF_INET; 63d9158b13Scgd name.sin_addr.s_addr = INADDR_ANY; 64d9158b13Scgd name.sin_port = 0; 65d9158b13Scgd if (bind(sock, &name, sizeof(name))) { 66d9158b13Scgd perror("binding datagram socket"); 67d9158b13Scgd exit(1); 68d9158b13Scgd } 69d9158b13Scgd /* Find assigned port value and print it out. */ 70d9158b13Scgd length = sizeof(name); 71d9158b13Scgd if (getsockname(sock, &name, &length)) { 72d9158b13Scgd perror("getting socket name"); 73d9158b13Scgd exit(1); 74d9158b13Scgd } 75d9158b13Scgd printf("Socket has port #%d\en", ntohs(name.sin_port)); 76d9158b13Scgd /* Read from the socket */ 77d9158b13Scgd if (read(sock, buf, 1024) < 0) 78d9158b13Scgd perror("receiving datagram packet"); 79d9158b13Scgd printf("-->%s\en", buf); 80d9158b13Scgd close(sock); 81d9158b13Scgd } 82