1 /*- 2 * Copyright (c) 2015 George V. Neville-Neil 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include <err.h> 30 #include <stdio.h> 31 #include <stdlib.h> 32 #include <strings.h> 33 #include <sysexits.h> 34 #include <unistd.h> 35 36 #include <sys/socket.h> 37 #include <sys/types.h> 38 #include <netinet/in.h> 39 40 #define PORT 6969 /* Default port */ 41 #define LISTEN 5 /* Default backlog */ 42 #define RECV_LIMIT 64 /* When do we move listen to 0? */ 43 44 void usage(void); 45 46 void usage() 47 { 48 err(EX_USAGE, "listen [-p port] [-l limit]\n"); 49 } 50 51 int main(int argc, char **argv) 52 { 53 54 int ch, srv_sock, cli_sock, recvd = 0; 55 int port = PORT; 56 int limit = LISTEN; 57 struct sockaddr_in localaddr; 58 59 while ((ch = getopt(argc, argv, "p:l:")) != -1) { 60 switch (ch) { 61 case 'p': 62 port = atoi(optarg); 63 break; 64 case 'l': 65 limit = atoi(optarg); 66 break; 67 case 'h': 68 default: 69 usage(); 70 } 71 } 72 73 bzero(&localaddr, sizeof(localaddr)); 74 localaddr.sin_len = sizeof(localaddr); 75 localaddr.sin_family = AF_INET; 76 localaddr.sin_port = htons(port); 77 localaddr.sin_addr.s_addr = INADDR_ANY; 78 79 srv_sock = socket(AF_INET, SOCK_STREAM, 0); 80 81 if (bind(srv_sock, (struct sockaddr *)&localaddr, 82 sizeof(struct sockaddr_in)) < 0) 83 err(EX_OSERR, "Could not bind to INADDR_ANY:%d", port); 84 85 if (listen(srv_sock, limit) < 0) 86 err(EX_OSERR, "Failed to listen with depth of %d\n", limit); 87 88 while (((cli_sock = accept(srv_sock, NULL, NULL)) >= 0) 89 && (recvd < RECV_LIMIT)) { 90 close(cli_sock); 91 recvd++; 92 } 93 94 listen(srv_sock, 0); 95 96 while (((cli_sock = accept(srv_sock, NULL, NULL)) >= 0) 97 && (recvd <= (RECV_LIMIT + limit + 1))) { 98 close(cli_sock); 99 recvd++; 100 } 101 102 if (accept(srv_sock, NULL, NULL) >= 0) 103 printf ("Late connection at %d\n", recvd); 104 else 105 printf("recvd %d\n", recvd); 106 } 107