probe.c revision 81697 
1/*-
2 * Copyright (c) 1998 Brian Somers <brian@Awfulhak.org>
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: head/usr.sbin/ppp/probe.c 81697 2001-08-15 13:53:38Z brian $
27 */
28
29#include <sys/time.h>
30#include <sys/socket.h>
31
32#include <unistd.h>
33
34#include "probe.h"
35#include "log.h"
36
37struct probe probe;
38
39/* Does select() alter the passed time value ? */
40static int
41select_changes_time(void)
42{
43  struct timeval t;
44
45  t.tv_sec = 0;
46  t.tv_usec = 100000;
47  select(0, NULL, NULL, NULL, &t);
48  return t.tv_usec != 100000;
49}
50
51#ifndef NOINET6
52static int
53ipv6_available(void)
54{
55  int s;
56
57  if ((s = ID0socket(AF_INET6, SOCK_DGRAM, 0)) == -1)
58    return 0;
59
60  close(s);
61  return 1;
62}
63#endif
64
65void
66probe_Init()
67{
68  probe.select_changes_time = select_changes_time() ? 1 : 0;
69  log_Printf(LogDEBUG, "Select changes time: %s\n",
70             probe.select_changes_time ? "yes" : "no");
71#ifndef NOINET6
72  probe.ipv6_available = ipv6_available() ? 1 : 0;
73  log_Printf(LogDEBUG, "IPv6 available: %s\n",
74             probe.ipv6_available ? "yes" : "no");
75#endif
76}
77