Commit | Line | Data |
a0d0e21e |
1 | package Net::Ping; |
2 | |
f06db76b |
3 | =head1 NAME |
4 | |
5 | Net::Ping, pingecho - check a host for upness |
6 | |
7 | =head1 SYNOPSIS |
8 | |
9 | use Net::Ping; |
10 | print "'jimmy' is alive and kicking\n" if pingecho('jimmy', 10) ; |
11 | |
12 | =head1 DESCRIPTION |
13 | |
14 | This module contains routines to test for the reachability of remote hosts. |
15 | Currently the only routine implemented is pingecho(). |
16 | |
17 | pingecho() uses a TCP echo (I<not> an ICMP one) to determine if the |
18 | remote host is reachable. This is usually adequate to tell that a remote |
19 | host is available to rsh(1), ftp(1), or telnet(1) onto. |
20 | |
21 | =head2 Parameters |
22 | |
23 | =over 5 |
24 | |
25 | =item hostname |
26 | |
27 | The remote host to check, specified either as a hostname or as an IP address. |
28 | |
29 | =item timeout |
30 | |
31 | The timeout in seconds. If not specified it will default to 5 seconds. |
32 | |
33 | =back |
34 | |
35 | =head1 WARNING |
36 | |
37 | pingecho() uses alarm to implement the timeout, so don't set another alarm |
38 | while you are using it. |
39 | |
40 | =cut |
41 | |
a0d0e21e |
42 | # Authors: karrer@bernina.ethz.ch (Andreas Karrer) |
43 | # pmarquess@bfsec.bt.co.uk (Paul Marquess) |
44 | |
45 | require Exporter; |
46 | |
47 | @ISA = qw(Exporter); |
48 | @EXPORT = qw(ping pingecho); |
49 | |
50 | use Socket; |
51 | use Carp ; |
52 | |
53 | $tcp_proto = (getprotobyname('tcp'))[2]; |
54 | $echo_port = (getservbyname('echo', 'tcp'))[2]; |
55 | |
56 | sub ping { |
57 | croak "ping not implemented yet. Use pingecho()"; |
58 | } |
59 | |
60 | |
61 | sub pingecho { |
62 | |
63 | croak "usage: pingecho host [timeout]" |
64 | unless @_ == 1 || @_ == 2 ; |
65 | |
66 | local ($host, $timeout) = @_; |
67 | local (*PINGSOCK); |
68 | local ($saddr, $ip); |
69 | local ($ret) ; |
70 | |
71 | # check if $host is alive by connecting to its echo port, within $timeout |
72 | # (default 5) seconds. returns 1 if OK, 0 if no answer, 0 if host not found |
73 | |
74 | $timeout = 5 unless $timeout; |
75 | |
76 | if ($host =~ /^\s*((\d+\.){3}\d+)\s*$/) |
77 | { $ip = pack ('C4', split (/\./, $1)) } |
78 | else |
79 | { $ip = (gethostbyname($host))[4] } |
80 | |
81 | return 0 unless $ip; # "no such host" |
82 | |
83 | $saddr = pack('S n a4 x8', AF_INET, $echo_port, $ip); |
84 | $SIG{'ALRM'} = sub { die } ; |
85 | alarm($timeout); |
86 | |
87 | $ret = eval <<'EOM' ; |
88 | |
89 | return 0 |
90 | unless socket(PINGSOCK, PF_INET, SOCK_STREAM, $tcp_proto) ; |
91 | |
92 | return 0 |
93 | unless connect(PINGSOCK, $saddr) ; |
94 | |
95 | return 1 ; |
96 | EOM |
97 | |
98 | alarm(0); |
99 | close(PINGSOCK); |
100 | $ret == 1 ? 1 : 0 ; |
101 | } |
102 | |
103 | 1; |