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 27 #include <err.h> 28 #include <stdio.h> 29 #include <stdlib.h> 30 #include <strings.h> 31 #include <sysexits.h> 32 #include <unistd.h> 33 34 #include <sys/socket.h> 35 #include <sys/types.h> 36 #include <netinet/in.h> 37 38 #define PORT 6969 /* Default port */ 39 #define LISTEN 5 /* Default backlog */ 40 #define RECV_LIMIT 64 /* When do we move listen to 0? */ 41 42 void usage(void); 43 44 void usage() 45 { 46 err(EX_USAGE, "listen [-p port] [-l limit]\n"); 47 } 48 49 int main(int argc, char **argv) 50 { 51 52 int ch, srv_sock, cli_sock, recvd = 0; 53 int port = PORT; 54 int limit = LISTEN; 55 struct sockaddr_in localaddr; 56 57 while ((ch = getopt(argc, argv, "p:l:")) != -1) { 58 switch (ch) { 59 case 'p': 60 port = atoi(optarg); 61 break; 62 case 'l': 63 limit = atoi(optarg); 64 break; 65 case 'h': 66 default: 67 usage(); 68 } 69 } 70 71 bzero(&localaddr, sizeof(localaddr)); 72 localaddr.sin_len = sizeof(localaddr); 73 localaddr.sin_family = AF_INET; 74 localaddr.sin_port = htons(port); 75 localaddr.sin_addr.s_addr = INADDR_ANY; 76 77 srv_sock = socket(AF_INET, SOCK_STREAM, 0); 78 79 if (bind(srv_sock, (struct sockaddr *)&localaddr, 80 sizeof(struct sockaddr_in)) < 0) 81 err(EX_OSERR, "Could not bind to INADDR_ANY:%d", port); 82 83 if (listen(srv_sock, limit) < 0) 84 err(EX_OSERR, "Failed to listen with depth of %d\n", limit); 85 86 while (((cli_sock = accept(srv_sock, NULL, NULL)) >= 0) 87 && (recvd < RECV_LIMIT)) { 88 close(cli_sock); 89 recvd++; 90 } 91 92 listen(srv_sock, 0); 93 94 while (((cli_sock = accept(srv_sock, NULL, NULL)) >= 0) 95 && (recvd <= (RECV_LIMIT + limit + 1))) { 96 close(cli_sock); 97 recvd++; 98 } 99 100 if (accept(srv_sock, NULL, NULL) >= 0) 101 printf ("Late connection at %d\n", recvd); 102 else 103 printf("recvd %d\n", recvd); 104 } 105