2 * Empire - A multi-player, client/server Internet based war game.
3 * Copyright (C) 1986-2006, Dave Pare, Jeff Bailey, Thomas Ruschak,
4 * Ken Stevens, Steve McClure
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 * See files README, COPYING and CREDITS in the root of the source
23 * tree for related information and legal notices. It is expected
24 * that future projects/authors will amend these files as needed.
28 * tcp_listen.c: Create a socket and listen on it
30 * Known contributors to this file:
31 * Markus Armbruster, 2005
41 #include <sys/types.h>
47 #include <sys/socket.h>
49 #include <arpa/inet.h>
50 #include <netinet/in.h>
53 #include "prototypes.h"
55 static int cant_listen(char *, char *, const char *);
58 tcp_listen(char *host, char *serv, size_t *addrlenp)
62 #ifdef HAVE_GETADDRINFO
64 * Inspired by example code from W. Richard Stevens: UNIX Network
68 struct addrinfo hints, *res, *ressave;
70 memset(&hints, 0, sizeof(struct addrinfo));
71 hints.ai_flags = AI_PASSIVE;
72 hints.ai_family = AF_UNSPEC;
73 hints.ai_socktype = SOCK_STREAM;
75 if ((n = getaddrinfo(host, serv, &hints, &res)) != 0)
76 cant_listen(host, serv, gai_strerror(n));
80 fd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
82 continue; /* error, try next one */
86 * SO_REUSEADDR requests to permit another bind even when the
87 * port is still in state TIME_WAIT. Windows' SO_REUSEADDR is
88 * broken: it makes bind() succeed no matter what, even if
89 * there's another server running on the same port. Luckily,
90 * bind() seems to be broken as well: it seems to suceed while
91 * the port in state TIME_WAIT by default; thus we get the
92 * behavior we want by not setting SO_REUSEADDR.
94 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0)
95 cant_listen(host, serv, strerror(errno));
97 if (bind(fd, res->ai_addr, res->ai_addrlen) == 0)
100 close(fd); /* error, close and try next one */
101 } while ((res = res->ai_next) != NULL);
103 if (res == NULL) /* errno from final socket() or bind() */
104 cant_listen(host, serv, strerror(errno));
106 if (listen(fd, SOMAXCONN) < 0)
107 cant_listen(host, serv, strerror(errno));
110 *addrlenp = res->ai_addrlen;
112 freeaddrinfo(ressave);
114 #else /* !HAVE_GETADDRINFO */
115 struct sockaddr_in sin;
119 memset(&sin, 0, sizeof(sin));
120 sin.sin_family = AF_INET;
122 sin.sin_addr.s_addr = htonl(INADDR_ANY);
123 else if (isdigit(*host))
124 sin.sin_addr.s_addr = inet_addr(host);
126 hp = gethostbyname(host);
128 cant_listen(host, serv, strerror(errno));
129 memcpy(&sin.sin_addr, hp->h_addr, sizeof(sin.sin_addr));
132 sin.sin_port = htons(atoi(serv));
134 sp = getservbyname(serv, "tcp");
136 cant_listen(host, serv, strerror(errno));
137 sin.sin_port = sp->s_port;
139 if ((fd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
140 cant_listen(host, serv, strerror(errno));
142 /* see comment on setsockopt() above */
143 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) < 0)
144 cant_listen(host, serv, strerror(errno));
146 if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)) < 0)
147 cant_listen(host, serv, strerror(errno));
148 if (listen(fd, SOMAXCONN) < 0)
149 cant_listen(host, serv, strerror(errno));
152 *addrlenp = sizeof(struct sockaddr_in);
154 #endif /* !HAVE_GETADDRINFO */
161 cant_listen(char *host, char *serv, const char *err)
163 fprintf(stderr, "Can't listen on %s:%s: %s", host, serv, err);