xref: /freebsd/usr.sbin/ppp/probe.c (revision ba3c1f5972d7b90feb6e6da47905ff2757e0fe57)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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  * $FreeBSD$
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 
41 struct probe probe;
42 
43 /* Does select() alter the passed time value ? */
44 static int
45 select_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
56 static int
57 ipv6_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 
69 void
70 probe_Init(void)
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