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
usage()44 void usage()
45 {
46 err(EX_USAGE, "listen [-p port] [-l limit]\n");
47 }
48
main(int argc,char ** argv)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