probe.c revision 330449 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1998 Brian Somers <brian@Awfulhak.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD: stable/11/usr.sbin/ppp/probe.c 330449 2018-03-05 07:26:05Z eadler $
29 */
30
31#include <sys/time.h>
32#include <sys/socket.h>
33
34#include <stdio.h>
35#include <unistd.h>
36
37#include "probe.h"
38#include "log.h"
39#include "id.h"
40
41struct probe probe;
42
43/* Does select() alter the passed time value ? */
44static int
45select_changes_time(void)
46{
47  struct timeval t;
48
49  t.tv_sec = 0;
50  t.tv_usec = 100000;
51  select(0, NULL, NULL, NULL, &t);
52  return t.tv_usec != 100000;
53}
54
55#ifndef NOINET6
56static int
57ipv6_available(void)
58{
59  int s;
60
61  if ((s = ID0socket(PF_INET6, SOCK_DGRAM, 0)) == -1)
62    return 0;
63
64  close(s);
65  return 1;
66}
67#endif
68
69void
70probe_Init()
71{
72  probe.select_changes_time = select_changes_time() ? 1 : 0;
73  log_Printf(LogDEBUG, "Select changes time: %s\n",
74             probe.select_changes_time ? "yes" : "no");
75#ifndef NOINET6
76  probe.ipv6_available = ipv6_available() ? 1 : 0;
77  log_Printf(LogDEBUG, "IPv6 available: %s\n",
78             probe.ipv6_available ? "yes" : "no");
79#endif
80}
81