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1 | package Net::Ping; |
2 | |
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3 | # $Id: Ping.pm,v 1.13 2001/12/07 02:18:44 rob Exp $ |
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4 | |
5 | require 5.002; |
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6 | require Exporter; |
7 | |
a3b93737 |
8 | use strict; |
b124990b |
9 | use vars qw(@ISA @EXPORT $VERSION |
10 | $def_timeout $def_proto $max_datasize $pingstring); |
a3b93737 |
11 | use FileHandle; |
12 | use Socket qw( SOCK_DGRAM SOCK_STREAM SOCK_RAW PF_INET |
b124990b |
13 | inet_aton sockaddr_in ); |
a3b93737 |
14 | use Carp; |
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15 | |
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16 | @ISA = qw(Exporter); |
a3b93737 |
17 | @EXPORT = qw(pingecho); |
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18 | $VERSION = 2.09; |
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19 | |
a3b93737 |
20 | # Constants |
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21 | |
a3b93737 |
22 | $def_timeout = 5; # Default timeout to wait for a reply |
23 | $def_proto = "udp"; # Default protocol to use for pinging |
24 | $max_datasize = 1024; # Maximum data bytes in a packet |
b124990b |
25 | # The data we exchange with the server for the stream protocol |
26 | $pingstring = "pingschwingping!\n"; |
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27 | |
a3b93737 |
28 | # Description: The pingecho() subroutine is provided for backward |
29 | # compatibility with the original Net::Ping. It accepts a host |
30 | # name/IP and an optional timeout in seconds. Create a tcp ping |
31 | # object and try pinging the host. The result of the ping is returned. |
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32 | |
a3b93737 |
33 | sub pingecho |
34 | { |
35 | my ($host, # Name or IP number of host to ping |
36 | $timeout # Optional timeout in seconds |
37 | ) = @_; |
38 | my ($p); # A ping object |
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39 | |
a3b93737 |
40 | $p = Net::Ping->new("tcp", $timeout); |
41 | $p->ping($host); # Going out of scope closes the connection |
42 | } |
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43 | |
a3b93737 |
44 | # Description: The new() method creates a new ping object. Optional |
45 | # parameters may be specified for the protocol to use, the timeout in |
46 | # seconds and the size in bytes of additional data which should be |
47 | # included in the packet. |
48 | # After the optional parameters are checked, the data is constructed |
49 | # and a socket is opened if appropriate. The object is returned. |
50 | |
51 | sub new |
52 | { |
53 | my ($this, |
54 | $proto, # Optional protocol to use for pinging |
55 | $timeout, # Optional timeout in seconds |
56 | $data_size # Optional additional bytes of data |
57 | ) = @_; |
58 | my $class = ref($this) || $this; |
59 | my $self = {}; |
60 | my ($cnt, # Count through data bytes |
61 | $min_datasize # Minimum data bytes required |
62 | ); |
63 | |
64 | bless($self, $class); |
65 | |
66 | $proto = $def_proto unless $proto; # Determine the protocol |
787ecdfa |
67 | croak('Protocol for ping must be "icmp", "udp", "tcp", "stream", or "external"') |
68 | unless $proto =~ m/^(icmp|udp|tcp|stream|external)$/; |
a3b93737 |
69 | $self->{"proto"} = $proto; |
70 | |
71 | $timeout = $def_timeout unless $timeout; # Determine the timeout |
72 | croak("Default timeout for ping must be greater than 0 seconds") |
73 | if $timeout <= 0; |
74 | $self->{"timeout"} = $timeout; |
75 | |
76 | $min_datasize = ($proto eq "udp") ? 1 : 0; # Determine data size |
77 | $data_size = $min_datasize unless defined($data_size) && $proto ne "tcp"; |
78 | croak("Data for ping must be from $min_datasize to $max_datasize bytes") |
79 | if ($data_size < $min_datasize) || ($data_size > $max_datasize); |
80 | $data_size-- if $self->{"proto"} eq "udp"; # We provide the first byte |
81 | $self->{"data_size"} = $data_size; |
82 | |
83 | $self->{"data"} = ""; # Construct data bytes |
84 | for ($cnt = 0; $cnt < $self->{"data_size"}; $cnt++) |
85 | { |
86 | $self->{"data"} .= chr($cnt % 256); |
87 | } |
88 | |
89 | $self->{"seq"} = 0; # For counting packets |
90 | if ($self->{"proto"} eq "udp") # Open a socket |
91 | { |
92 | $self->{"proto_num"} = (getprotobyname('udp'))[2] || |
93 | croak("Can't udp protocol by name"); |
94 | $self->{"port_num"} = (getservbyname('echo', 'udp'))[2] || |
95 | croak("Can't get udp echo port by name"); |
96 | $self->{"fh"} = FileHandle->new(); |
97 | socket($self->{"fh"}, &PF_INET(), &SOCK_DGRAM(), |
98 | $self->{"proto_num"}) || |
99 | croak("udp socket error - $!"); |
100 | } |
101 | elsif ($self->{"proto"} eq "icmp") |
102 | { |
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103 | croak("icmp ping requires root privilege") if ($> and $^O ne 'VMS'); |
a3b93737 |
104 | $self->{"proto_num"} = (getprotobyname('icmp'))[2] || |
105 | croak("Can't get icmp protocol by name"); |
106 | $self->{"pid"} = $$ & 0xffff; # Save lower 16 bits of pid |
107 | $self->{"fh"} = FileHandle->new(); |
108 | socket($self->{"fh"}, &PF_INET(), &SOCK_RAW(), $self->{"proto_num"}) || |
109 | croak("icmp socket error - $!"); |
110 | } |
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111 | elsif ($self->{"proto"} eq "tcp" || $self->{"proto"} eq "stream") |
a3b93737 |
112 | { |
113 | $self->{"proto_num"} = (getprotobyname('tcp'))[2] || |
114 | croak("Can't get tcp protocol by name"); |
115 | $self->{"port_num"} = (getservbyname('echo', 'tcp'))[2] || |
116 | croak("Can't get tcp echo port by name"); |
117 | $self->{"fh"} = FileHandle->new(); |
118 | } |
119 | |
120 | |
121 | return($self); |
122 | } |
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123 | |
a3b93737 |
124 | # Description: Ping a host name or IP number with an optional timeout. |
125 | # First lookup the host, and return undef if it is not found. Otherwise |
b124990b |
126 | # perform the specific ping method based on the protocol. Return the |
a3b93737 |
127 | # result of the ping. |
128 | |
129 | sub ping |
130 | { |
131 | my ($self, |
132 | $host, # Name or IP number of host to ping |
133 | $timeout # Seconds after which ping times out |
134 | ) = @_; |
135 | my ($ip, # Packed IP number of $host |
136 | $ret # The return value |
137 | ); |
138 | |
139 | croak("Usage: \$p->ping(\$host [, \$timeout])") unless @_ == 2 || @_ == 3; |
140 | $timeout = $self->{"timeout"} unless $timeout; |
141 | croak("Timeout must be greater than 0 seconds") if $timeout <= 0; |
142 | |
143 | $ip = inet_aton($host); |
144 | return(undef) unless defined($ip); # Does host exist? |
145 | |
787ecdfa |
146 | # Dispatch to the appropriate routine. |
147 | return $self->ping_external($ip, $timeout) if $self->{"proto"} eq "external"; |
148 | return $self->ping_udp($ip, $timeout) if $self->{"proto"} eq "udp"; |
149 | return $self->ping_icmp($ip, $timeout) if $self->{"proto"} eq "icmp"; |
150 | return $self->ping_tcp($ip, $timeout) if $self->{"proto"} eq "tcp"; |
151 | return $self->ping_stream($ip, $timeout) if $self->{"proto"} eq "stream"; |
152 | |
153 | croak("Unknown protocol \"$self->{proto}\" in ping()"); |
154 | } |
155 | |
156 | # Uses Net::Ping::External to do an external ping. |
157 | sub ping_external { |
158 | my ($self, |
159 | $ip, # Packed IP number of the host |
160 | $timeout # Seconds after which ping times out |
161 | ) = @_; |
162 | |
b124990b |
163 | eval { require Net::Ping::External; } |
164 | or croak('Protocol "external" not supported on your system: Net::Ping::External not found'); |
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165 | return Net::Ping::External::ping(ip => $ip, timeout => $timeout); |
a3b93737 |
166 | } |
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167 | |
a3b93737 |
168 | sub ping_icmp |
169 | { |
170 | my ($self, |
171 | $ip, # Packed IP number of the host |
172 | $timeout # Seconds after which ping times out |
173 | ) = @_; |
174 | |
175 | my $ICMP_ECHOREPLY = 0; # ICMP packet types |
176 | my $ICMP_ECHO = 8; |
177 | my $icmp_struct = "C2 S3 A"; # Structure of a minimal ICMP packet |
178 | my $subcode = 0; # No ICMP subcode for ECHO and ECHOREPLY |
179 | my $flags = 0; # No special flags when opening a socket |
180 | my $port = 0; # No port with ICMP |
181 | |
182 | my ($saddr, # sockaddr_in with port and ip |
183 | $checksum, # Checksum of ICMP packet |
184 | $msg, # ICMP packet to send |
185 | $len_msg, # Length of $msg |
186 | $rbits, # Read bits, filehandles for reading |
187 | $nfound, # Number of ready filehandles found |
188 | $finish_time, # Time ping should be finished |
189 | $done, # set to 1 when we are done |
190 | $ret, # Return value |
191 | $recv_msg, # Received message including IP header |
192 | $from_saddr, # sockaddr_in of sender |
193 | $from_port, # Port packet was sent from |
194 | $from_ip, # Packed IP of sender |
195 | $from_type, # ICMP type |
196 | $from_subcode, # ICMP subcode |
197 | $from_chk, # ICMP packet checksum |
198 | $from_pid, # ICMP packet id |
199 | $from_seq, # ICMP packet sequence |
200 | $from_msg # ICMP message |
201 | ); |
202 | |
203 | $self->{"seq"} = ($self->{"seq"} + 1) % 65536; # Increment sequence |
204 | $checksum = 0; # No checksum for starters |
205 | $msg = pack($icmp_struct . $self->{"data_size"}, $ICMP_ECHO, $subcode, |
206 | $checksum, $self->{"pid"}, $self->{"seq"}, $self->{"data"}); |
207 | $checksum = Net::Ping->checksum($msg); |
208 | $msg = pack($icmp_struct . $self->{"data_size"}, $ICMP_ECHO, $subcode, |
209 | $checksum, $self->{"pid"}, $self->{"seq"}, $self->{"data"}); |
210 | $len_msg = length($msg); |
211 | $saddr = sockaddr_in($port, $ip); |
212 | send($self->{"fh"}, $msg, $flags, $saddr); # Send the message |
213 | |
214 | $rbits = ""; |
215 | vec($rbits, $self->{"fh"}->fileno(), 1) = 1; |
8e07c86e |
216 | $ret = 0; |
a3b93737 |
217 | $done = 0; |
218 | $finish_time = time() + $timeout; # Must be done by this time |
219 | while (!$done && $timeout > 0) # Keep trying if we have time |
220 | { |
221 | $nfound = select($rbits, undef, undef, $timeout); # Wait for packet |
222 | $timeout = $finish_time - time(); # Get remaining time |
223 | if (!defined($nfound)) # Hmm, a strange error |
224 | { |
225 | $ret = undef; |
226 | $done = 1; |
227 | } |
228 | elsif ($nfound) # Got a packet from somewhere |
229 | { |
230 | $recv_msg = ""; |
231 | $from_saddr = recv($self->{"fh"}, $recv_msg, 1500, $flags); |
232 | ($from_port, $from_ip) = sockaddr_in($from_saddr); |
233 | ($from_type, $from_subcode, $from_chk, |
234 | $from_pid, $from_seq, $from_msg) = |
235 | unpack($icmp_struct . $self->{"data_size"}, |
236 | substr($recv_msg, length($recv_msg) - $len_msg, |
237 | $len_msg)); |
238 | if (($from_type == $ICMP_ECHOREPLY) && |
239 | ($from_ip eq $ip) && |
240 | ($from_pid == $self->{"pid"}) && # Does the packet check out? |
241 | ($from_seq == $self->{"seq"})) |
242 | { |
243 | $ret = 1; # It's a winner |
244 | $done = 1; |
245 | } |
246 | } |
247 | else # Oops, timed out |
248 | { |
249 | $done = 1; |
250 | } |
251 | } |
252 | return($ret) |
253 | } |
254 | |
255 | # Description: Do a checksum on the message. Basically sum all of |
256 | # the short words and fold the high order bits into the low order bits. |
257 | |
258 | sub checksum |
259 | { |
260 | my ($class, |
261 | $msg # The message to checksum |
262 | ) = @_; |
263 | my ($len_msg, # Length of the message |
264 | $num_short, # The number of short words in the message |
265 | $short, # One short word |
266 | $chk # The checksum |
267 | ); |
268 | |
269 | $len_msg = length($msg); |
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270 | $num_short = int($len_msg / 2); |
a3b93737 |
271 | $chk = 0; |
272 | foreach $short (unpack("S$num_short", $msg)) |
273 | { |
274 | $chk += $short; |
275 | } # Add the odd byte in |
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276 | $chk += (unpack("C", substr($msg, $len_msg - 1, 1)) << 8) if $len_msg % 2; |
a3b93737 |
277 | $chk = ($chk >> 16) + ($chk & 0xffff); # Fold high into low |
278 | return(~(($chk >> 16) + $chk) & 0xffff); # Again and complement |
279 | } |
280 | |
787ecdfa |
281 | |
b124990b |
282 | # Description: Perform a tcp echo ping. Since a tcp connection is |
283 | # host specific, we have to open and close each connection here. We |
284 | # can't just leave a socket open. Because of the robust nature of |
285 | # tcp, it will take a while before it gives up trying to establish a |
286 | # connection. Therefore, we use select() on a non-blocking socket to |
287 | # check against our timeout. No data bytes are actually |
288 | # sent since the successful establishment of a connection is proof |
289 | # enough of the reachability of the remote host. Also, tcp is |
290 | # expensive and doesn't need our help to add to the overhead. |
291 | |
292 | sub ping_tcp |
787ecdfa |
293 | { |
294 | my ($self, |
295 | $ip, # Packed IP number of the host |
b124990b |
296 | $timeout # Seconds after which ping times out |
787ecdfa |
297 | ) = @_; |
b124990b |
298 | my ($ret # The return value |
787ecdfa |
299 | ); |
300 | |
b124990b |
301 | $@ = ""; |
302 | $ret = $self -> tcp_connect( $ip, $timeout); |
303 | $ret = 1 if $@ =~ /(Connection Refused|Unknown Error)/i; |
787ecdfa |
304 | $self->{"fh"}->close(); |
b124990b |
305 | return($ret); |
787ecdfa |
306 | } |
307 | |
b124990b |
308 | sub tcp_connect |
787ecdfa |
309 | { |
310 | my ($self, |
311 | $ip, # Packed IP number of the host |
b124990b |
312 | $timeout # Seconds after which connect times out |
787ecdfa |
313 | ) = @_; |
b124990b |
314 | my ($saddr); # Packed IP and Port |
787ecdfa |
315 | |
b124990b |
316 | $saddr = sockaddr_in($self->{"port_num"}, $ip); |
787ecdfa |
317 | |
b124990b |
318 | my $ret = 0; # Default to unreachable |
787ecdfa |
319 | |
b124990b |
320 | my $do_socket = sub { |
321 | socket($self->{"fh"}, &PF_INET(), &SOCK_STREAM(), $self->{"proto_num"}) || |
322 | croak("tcp socket error - $!"); |
323 | }; |
324 | my $do_connect = sub { |
325 | eval { |
326 | die $! unless connect($self->{"fh"}, $saddr); |
327 | $self->{"ip"} = $ip; |
328 | $ret = 1; |
329 | }; |
330 | $ret; |
331 | }; |
332 | |
333 | if ($^O =~ /Win32/i) { |
334 | |
335 | # Buggy Winsock API doesn't allow us to use alarm() calls. |
336 | # Hence, if our OS is Windows, we need to create a separate |
337 | # process to do the blocking connect attempt. |
338 | |
339 | $| = 1; # Clear buffer prior to fork to prevent duplicate flushing. |
340 | my $pid = fork; |
341 | if (!$pid) { |
342 | if (!defined $pid) { |
343 | # Fork did not work |
344 | warn "Win32 Fork error: $!"; |
345 | return 0; |
346 | } |
347 | &{ $do_socket }(); |
348 | |
349 | # Try a slow blocking connect() call |
350 | # and report the status to the pipe. |
351 | if ( &{ $do_connect }() ) { |
352 | $self->{"fh"}->close(); |
353 | # No error |
354 | exit 0; |
355 | } else { |
356 | # Pass the error status to the parent |
357 | exit $!; |
358 | } |
359 | } |
360 | |
361 | &{ $do_socket }(); |
362 | |
363 | my $patience = time + $timeout; |
364 | |
365 | require POSIX; |
366 | my ($child); |
367 | $? = 0; |
368 | # Wait up to the timeout |
369 | # And clean off the zombie |
370 | do { |
371 | $child = waitpid($pid, &POSIX::WNOHANG); |
372 | $! = $? >> 8; |
373 | $@ = $!; |
c798bd21 |
374 | select(undef, undef, undef, 0.1); |
b124990b |
375 | } while time < $patience && $child != $pid; |
376 | |
377 | if ($child == $pid) { |
378 | # Since she finished within the timeout, |
379 | # it is probably safe for me to try it too |
380 | &{ $do_connect }(); |
381 | } else { |
382 | # Time must have run out. |
383 | $@ = "Timed out!"; |
384 | # Put that choking client out of its misery |
385 | kill "KILL", $pid; |
386 | # Clean off the zombie |
387 | waitpid($pid, 0); |
388 | $ret = 0; |
389 | } |
390 | } else { # Win32 |
391 | # Otherwise don't waste the resources to fork |
392 | |
393 | &{ $do_socket }(); |
394 | |
395 | $SIG{'ALRM'} = sub { die "Timed out!"; }; |
396 | alarm($timeout); # Interrupt connect() if we have to |
397 | |
398 | &{ $do_connect }(); |
399 | alarm(0); |
400 | } |
787ecdfa |
401 | |
b124990b |
402 | return $ret; |
787ecdfa |
403 | } |
404 | |
405 | # This writes the given string to the socket and then reads it |
406 | # back. It returns 1 on success, 0 on failure. |
407 | sub tcp_echo |
408 | { |
b124990b |
409 | my $self = shift; |
410 | my $timeout = shift; |
411 | my $pingstring = shift; |
787ecdfa |
412 | |
b124990b |
413 | my $ret = undef; |
414 | my $time = time; |
415 | my $wrstr = $pingstring; |
416 | my $rdstr = ""; |
787ecdfa |
417 | |
418 | eval <<'EOM'; |
b124990b |
419 | do { |
420 | my $rin = ""; |
421 | vec($rin, $self->{"fh"}->fileno(), 1) = 1; |
422 | |
423 | my $rout = undef; |
424 | if($wrstr) { |
425 | $rout = ""; |
426 | vec($rout, $self->{"fh"}->fileno(), 1) = 1; |
427 | } |
428 | |
429 | if(select($rin, $rout, undef, ($time + $timeout) - time())) { |
430 | |
431 | if($rout && vec($rout,$self->{"fh"}->fileno(),1)) { |
432 | my $num = syswrite($self->{"fh"}, $wrstr); |
433 | if($num) { |
434 | # If it was a partial write, update and try again. |
435 | $wrstr = substr($wrstr,$num); |
436 | } else { |
437 | # There was an error. |
438 | $ret = 0; |
439 | } |
440 | } |
441 | |
442 | if(vec($rin,$self->{"fh"}->fileno(),1)) { |
443 | my $reply; |
444 | if(sysread($self->{"fh"},$reply,length($pingstring)-length($rdstr))) { |
445 | $rdstr .= $reply; |
446 | $ret = 1 if $rdstr eq $pingstring; |
447 | } else { |
448 | # There was an error. |
449 | $ret = 0; |
450 | } |
451 | } |
452 | |
453 | } |
454 | } until time() > ($time + $timeout) || defined($ret); |
787ecdfa |
455 | EOM |
456 | |
b124990b |
457 | return $ret; |
787ecdfa |
458 | } |
459 | |
787ecdfa |
460 | |
787ecdfa |
461 | |
787ecdfa |
462 | |
463 | # Description: Perform a stream ping. If the tcp connection isn't |
464 | # already open, it opens it. It then sends some data and waits for |
465 | # a reply. It leaves the stream open on exit. |
466 | |
467 | sub ping_stream |
468 | { |
469 | my ($self, |
470 | $ip, # Packed IP number of the host |
471 | $timeout # Seconds after which ping times out |
072620d9 |
472 | ) = @_; |
473 | |
787ecdfa |
474 | # Open the stream if it's not already open |
475 | if(!defined $self->{"fh"}->fileno()) { |
476 | $self->tcp_connect($ip, $timeout) or return 0; |
477 | } |
072620d9 |
478 | |
787ecdfa |
479 | croak "tried to switch servers while stream pinging" |
480 | if $self->{"ip"} ne $ip; |
481 | |
b124990b |
482 | return $self->tcp_echo($timeout, $pingstring); |
787ecdfa |
483 | } |
484 | |
485 | # Description: opens the stream. You would do this if you want to |
486 | # separate the overhead of opening the stream from the first ping. |
487 | |
488 | sub open |
489 | { |
b124990b |
490 | my ($self, |
491 | $host, # Host or IP address |
787ecdfa |
492 | $timeout # Seconds after which open times out |
b124990b |
493 | ) = @_; |
787ecdfa |
494 | |
b124990b |
495 | my ($ip); # Packed IP number of the host |
496 | $ip = inet_aton($host); |
497 | $timeout = $self->{"timeout"} unless $timeout; |
787ecdfa |
498 | |
b124990b |
499 | if($self->{"proto"} eq "stream") { |
500 | if(defined($self->{"fh"}->fileno())) { |
501 | croak("socket is already open"); |
502 | } else { |
503 | $self->tcp_connect($ip, $timeout); |
504 | } |
505 | } |
072620d9 |
506 | } |
507 | |
b124990b |
508 | |
a3b93737 |
509 | # Description: Perform a udp echo ping. Construct a message of |
510 | # at least the one-byte sequence number and any additional data bytes. |
511 | # Send the message out and wait for a message to come back. If we |
512 | # get a message, make sure all of its parts match. If they do, we are |
513 | # done. Otherwise go back and wait for the message until we run out |
514 | # of time. Return the result of our efforts. |
515 | |
516 | sub ping_udp |
517 | { |
518 | my ($self, |
519 | $ip, # Packed IP number of the host |
520 | $timeout # Seconds after which ping times out |
521 | ) = @_; |
522 | |
523 | my $flags = 0; # Nothing special on open |
524 | |
525 | my ($saddr, # sockaddr_in with port and ip |
526 | $ret, # The return value |
527 | $msg, # Message to be echoed |
528 | $finish_time, # Time ping should be finished |
529 | $done, # Set to 1 when we are done pinging |
530 | $rbits, # Read bits, filehandles for reading |
531 | $nfound, # Number of ready filehandles found |
532 | $from_saddr, # sockaddr_in of sender |
533 | $from_msg, # Characters echoed by $host |
534 | $from_port, # Port message was echoed from |
535 | $from_ip # Packed IP number of sender |
536 | ); |
537 | |
538 | $saddr = sockaddr_in($self->{"port_num"}, $ip); |
539 | $self->{"seq"} = ($self->{"seq"} + 1) % 256; # Increment sequence |
540 | $msg = chr($self->{"seq"}) . $self->{"data"}; # Add data if any |
541 | send($self->{"fh"}, $msg, $flags, $saddr); # Send it |
542 | |
543 | $rbits = ""; |
544 | vec($rbits, $self->{"fh"}->fileno(), 1) = 1; |
545 | $ret = 0; # Default to unreachable |
546 | $done = 0; |
547 | $finish_time = time() + $timeout; # Ping needs to be done by then |
548 | while (!$done && $timeout > 0) |
549 | { |
550 | $nfound = select($rbits, undef, undef, $timeout); # Wait for response |
551 | $timeout = $finish_time - time(); # Get remaining time |
552 | |
553 | if (!defined($nfound)) # Hmm, a strange error |
554 | { |
555 | $ret = undef; |
556 | $done = 1; |
557 | } |
558 | elsif ($nfound) # A packet is waiting |
559 | { |
560 | $from_msg = ""; |
787ecdfa |
561 | $from_saddr = recv($self->{"fh"}, $from_msg, 1500, $flags) |
562 | or last; # For example an unreachable host will make recv() fail. |
563 | ($from_port, $from_ip) = sockaddr_in($from_saddr); |
564 | if (($from_ip eq $ip) && # Does the packet check out? |
565 | ($from_port == $self->{"port_num"}) && |
566 | ($from_msg eq $msg)) |
567 | { |
568 | $ret = 1; # It's a winner |
569 | $done = 1; |
570 | } |
571 | } |
a3b93737 |
572 | else # Oops, timed out |
573 | { |
574 | $done = 1; |
575 | } |
576 | } |
577 | return($ret); |
b124990b |
578 | } |
a0d0e21e |
579 | |
a3b93737 |
580 | # Description: Close the connection unless we are using the tcp |
581 | # protocol, since it will already be closed. |
582 | |
583 | sub close |
584 | { |
585 | my ($self) = @_; |
586 | |
587 | $self->{"fh"}->close() unless $self->{"proto"} eq "tcp"; |
588 | } |
589 | |
590 | |
a0d0e21e |
591 | 1; |
8e07c86e |
592 | __END__ |
593 | |
8e07c86e |
594 | =head1 NAME |
595 | |
a3b93737 |
596 | Net::Ping - check a remote host for reachability |
8e07c86e |
597 | |
c798bd21 |
598 | $Id: Ping.pm,v 1.13 2001/12/07 02:18:44 rob Exp $ |
b124990b |
599 | |
8e07c86e |
600 | =head1 SYNOPSIS |
601 | |
602 | use Net::Ping; |
8e07c86e |
603 | |
a3b93737 |
604 | $p = Net::Ping->new(); |
605 | print "$host is alive.\n" if $p->ping($host); |
606 | $p->close(); |
607 | |
608 | $p = Net::Ping->new("icmp"); |
609 | foreach $host (@host_array) |
610 | { |
611 | print "$host is "; |
612 | print "NOT " unless $p->ping($host, 2); |
613 | print "reachable.\n"; |
614 | sleep(1); |
615 | } |
616 | $p->close(); |
b124990b |
617 | |
a3b93737 |
618 | $p = Net::Ping->new("tcp", 2); |
b124990b |
619 | # Try connecting to the www port instead of the echo port |
620 | $p->{port_num} = getservbyname("http", "tcp"); |
a3b93737 |
621 | while ($stop_time > time()) |
622 | { |
623 | print "$host not reachable ", scalar(localtime()), "\n" |
624 | unless $p->ping($host); |
625 | sleep(300); |
626 | } |
627 | undef($p); |
b124990b |
628 | |
a3b93737 |
629 | # For backward compatibility |
630 | print "$host is alive.\n" if pingecho($host); |
8e07c86e |
631 | |
a3b93737 |
632 | =head1 DESCRIPTION |
8e07c86e |
633 | |
a3b93737 |
634 | This module contains methods to test the reachability of remote |
635 | hosts on a network. A ping object is first created with optional |
636 | parameters, a variable number of hosts may be pinged multiple |
637 | times and then the connection is closed. |
638 | |
b124990b |
639 | You may choose one of four different protocols to use for the |
640 | ping. The "udp" protocol is the default. Note that a live remote host |
641 | may still fail to be pingable by one or more of these protocols. For |
642 | example, www.microsoft.com is generally alive but not pingable. |
787ecdfa |
643 | |
b124990b |
644 | With the "tcp" protocol the ping() method attempts to establish a |
645 | connection to the remote host's echo port. If the connection is |
646 | successfully established, the remote host is considered reachable. No |
647 | data is actually echoed. This protocol does not require any special |
648 | privileges but has higher overhead than the other two protocols. |
072620d9 |
649 | |
b124990b |
650 | Specifying the "udp" protocol causes the ping() method to send a udp |
a3b93737 |
651 | packet to the remote host's echo port. If the echoed packet is |
652 | received from the remote host and the received packet contains the |
653 | same data as the packet that was sent, the remote host is considered |
654 | reachable. This protocol does not require any special privileges. |
b124990b |
655 | It should be borne in mind that, for a udp ping, a host |
787ecdfa |
656 | will be reported as unreachable if it is not running the |
b124990b |
657 | appropriate echo service. For Unix-like systems see L<inetd(8)> |
658 | for more information. |
787ecdfa |
659 | |
b124990b |
660 | If the "icmp" protocol is specified, the ping() method sends an icmp |
661 | echo message to the remote host, which is what the UNIX ping program |
662 | does. If the echoed message is received from the remote host and |
663 | the echoed information is correct, the remote host is considered |
664 | reachable. Specifying the "icmp" protocol requires that the program |
665 | be run as root or that the program be setuid to root. |
787ecdfa |
666 | |
b124990b |
667 | If the "external" protocol is specified, the ping() method attempts to |
668 | use the C<Net::Ping::External> module to ping the remote host. |
669 | C<Net::Ping::External> interfaces with your system's default C<ping> |
670 | utility to perform the ping, and generally produces relatively |
787ecdfa |
671 | accurate results. If C<Net::Ping::External> if not installed on your |
672 | system, specifying the "external" protocol will result in an error. |
edc5bd88 |
673 | |
a3b93737 |
674 | =head2 Functions |
675 | |
676 | =over 4 |
677 | |
678 | =item Net::Ping->new([$proto [, $def_timeout [, $bytes]]]); |
679 | |
680 | Create a new ping object. All of the parameters are optional. $proto |
681 | specifies the protocol to use when doing a ping. The current choices |
682 | are "tcp", "udp" or "icmp". The default is "udp". |
683 | |
684 | If a default timeout ($def_timeout) in seconds is provided, it is used |
685 | when a timeout is not given to the ping() method (below). The timeout |
686 | must be greater than 0 and the default, if not specified, is 5 seconds. |
687 | |
688 | If the number of data bytes ($bytes) is given, that many data bytes |
689 | are included in the ping packet sent to the remote host. The number of |
690 | data bytes is ignored if the protocol is "tcp". The minimum (and |
691 | default) number of data bytes is 1 if the protocol is "udp" and 0 |
692 | otherwise. The maximum number of data bytes that can be specified is |
693 | 1024. |
694 | |
695 | =item $p->ping($host [, $timeout]); |
696 | |
697 | Ping the remote host and wait for a response. $host can be either the |
698 | hostname or the IP number of the remote host. The optional timeout |
699 | must be greater than 0 seconds and defaults to whatever was specified |
700 | when the ping object was created. If the hostname cannot be found or |
701 | there is a problem with the IP number, undef is returned. Otherwise, |
702 | 1 is returned if the host is reachable and 0 if it is not. For all |
703 | practical purposes, undef and 0 and can be treated as the same case. |
704 | |
787ecdfa |
705 | =item $p->open($host); |
706 | |
707 | When you are using the stream protocol, this call pre-opens the |
708 | tcp socket. It's only necessary to do this if you want to |
709 | provide a different timeout when creating the connection, or |
710 | remove the overhead of establishing the connection from the |
711 | first ping. If you don't call C<open()>, the connection is |
b124990b |
712 | automatically opened the first time C<ping()> is called. |
713 | This call simply does nothing if you are using any protocol other |
714 | than stream. |
715 | |
716 | =item $p->open($host); |
717 | |
718 | When you are using the stream protocol, this call pre-opens the |
719 | tcp socket. It's only necessary to do this if you want to |
720 | provide a different timeout when creating the connection, or |
721 | remove the overhead of establishing the connection from the |
722 | first ping. If you don't call C<open()>, the connection is |
723 | automatically opened the first time C<ping()> is called. |
787ecdfa |
724 | This call simply does nothing if you are using any protocol other |
725 | than stream. |
726 | |
a3b93737 |
727 | =item $p->close(); |
728 | |
729 | Close the network connection for this ping object. The network |
730 | connection is also closed by "undef $p". The network connection is |
731 | automatically closed if the ping object goes out of scope (e.g. $p is |
732 | local to a subroutine and you leave the subroutine). |
733 | |
734 | =item pingecho($host [, $timeout]); |
735 | |
736 | To provide backward compatibility with the previous version of |
737 | Net::Ping, a pingecho() subroutine is available with the same |
738 | functionality as before. pingecho() uses the tcp protocol. The |
739 | return values and parameters are the same as described for the ping() |
740 | method. This subroutine is obsolete and may be removed in a future |
741 | version of Net::Ping. |
8e07c86e |
742 | |
a3b93737 |
743 | =back |
8e07c86e |
744 | |
b124990b |
745 | =head1 WARNING |
746 | |
747 | pingecho() or a ping object with the tcp protocol use alarm() to |
748 | implement the timeout. So, don't use alarm() in your program while |
749 | you are using pingecho() or a ping object with the tcp protocol. The |
750 | udp and icmp protocols do not use alarm() to implement the timeout. |
751 | |
a3b93737 |
752 | =head1 NOTES |
8e07c86e |
753 | |
a3b93737 |
754 | There will be less network overhead (and some efficiency in your |
755 | program) if you specify either the udp or the icmp protocol. The tcp |
756 | protocol will generate 2.5 times or more traffic for each ping than |
757 | either udp or icmp. If many hosts are pinged frequently, you may wish |
758 | to implement a small wait (e.g. 25ms or more) between each ping to |
759 | avoid flooding your network with packets. |
8e07c86e |
760 | |
a3b93737 |
761 | The icmp protocol requires that the program be run as root or that it |
787ecdfa |
762 | be setuid to root. The other protocols do not require special |
763 | privileges, but not all network devices implement tcp or udp echo. |
8e07c86e |
764 | |
a3b93737 |
765 | Local hosts should normally respond to pings within milliseconds. |
766 | However, on a very congested network it may take up to 3 seconds or |
767 | longer to receive an echo packet from the remote host. If the timeout |
768 | is set too low under these conditions, it will appear that the remote |
769 | host is not reachable (which is almost the truth). |
8e07c86e |
770 | |
a3b93737 |
771 | Reachability doesn't necessarily mean that the remote host is actually |
787ecdfa |
772 | functioning beyond its ability to echo packets. tcp is slightly better |
773 | at indicating the health of a system than icmp because it uses more |
774 | of the networking stack to respond. |
8e07c86e |
775 | |
a3b93737 |
776 | Because of a lack of anything better, this module uses its own |
777 | routines to pack and unpack ICMP packets. It would be better for a |
778 | separate module to be written which understands all of the different |
779 | kinds of ICMP packets. |
8e07c86e |
780 | |
b124990b |
781 | =head1 AUTHOR(S) |
782 | |
783 | Current maintainer Net::Ping base code: |
784 | colinm@cpan.org (Colin McMillen) |
785 | |
786 | Stream protocol: |
787 | bronson@trestle.com (Scott Bronson) |
788 | |
789 | Original pingecho(): |
790 | karrer@bernina.ethz.ch (Andreas Karrer) |
791 | pmarquess@bfsec.bt.co.uk (Paul Marquess) |
792 | |
793 | Original Net::Ping author: |
794 | mose@ns.ccsn.edu (Russell Mosemann) |
795 | |
796 | Compatibility porting: |
797 | bbb@cpan.org (Rob Brown) |
798 | |
799 | =head1 COPYRIGHT |
800 | |
801 | Copyright (c) 2001, Colin McMillen. All rights reserved. |
802 | Copyright (c) 2001, Rob Brown. All rights reserved. |
803 | |
804 | This program is free software; you may redistribute it and/or |
805 | modify it under the same terms as Perl itself. |
806 | |
a3b93737 |
807 | =cut |