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1 | package Net::Ping; |
2 | |
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3 | # $Id: Ping.pm,v 1.27 2002/04/02 02:01:21 rob Exp $ |
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4 | |
5 | require 5.002; |
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6 | require Exporter; |
7 | |
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8 | use strict; |
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9 | use vars qw(@ISA @EXPORT $VERSION |
e82f584b |
10 | $def_timeout $def_proto $max_datasize $pingstring $hires); |
a3b93737 |
11 | use FileHandle; |
12 | use Socket qw( SOCK_DGRAM SOCK_STREAM SOCK_RAW PF_INET |
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13 | inet_aton inet_ntoa sockaddr_in ); |
a3b93737 |
14 | use Carp; |
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15 | use Errno qw(ECONNREFUSED); |
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16 | |
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17 | @ISA = qw(Exporter); |
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18 | @EXPORT = qw(pingecho); |
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19 | $VERSION = "2.14"; |
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20 | |
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21 | # Constants |
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22 | |
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23 | $def_timeout = 5; # Default timeout to wait for a reply |
24 | $def_proto = "udp"; # Default protocol to use for pinging |
25 | $max_datasize = 1024; # Maximum data bytes in a packet |
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26 | # The data we exchange with the server for the stream protocol |
27 | $pingstring = "pingschwingping!\n"; |
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28 | |
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29 | # Description: The pingecho() subroutine is provided for backward |
30 | # compatibility with the original Net::Ping. It accepts a host |
31 | # name/IP and an optional timeout in seconds. Create a tcp ping |
32 | # object and try pinging the host. The result of the ping is returned. |
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33 | |
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34 | sub pingecho |
35 | { |
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36 | my ($host, # Name or IP number of host to ping |
37 | $timeout # Optional timeout in seconds |
38 | ) = @_; |
39 | my ($p); # A ping object |
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40 | |
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41 | $p = Net::Ping->new("tcp", $timeout); |
42 | $p->ping($host); # Going out of scope closes the connection |
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43 | } |
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44 | |
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45 | # Description: The new() method creates a new ping object. Optional |
46 | # parameters may be specified for the protocol to use, the timeout in |
47 | # seconds and the size in bytes of additional data which should be |
48 | # included in the packet. |
49 | # After the optional parameters are checked, the data is constructed |
50 | # and a socket is opened if appropriate. The object is returned. |
51 | |
52 | sub new |
53 | { |
e82f584b |
54 | my ($this, |
55 | $proto, # Optional protocol to use for pinging |
56 | $timeout, # Optional timeout in seconds |
57 | $data_size # Optional additional bytes of data |
58 | ) = @_; |
59 | my $class = ref($this) || $this; |
60 | my $self = {}; |
61 | my ($cnt, # Count through data bytes |
62 | $min_datasize # Minimum data bytes required |
63 | ); |
64 | |
65 | bless($self, $class); |
66 | |
67 | $proto = $def_proto unless $proto; # Determine the protocol |
68 | croak('Protocol for ping must be "icmp", "udp", "tcp", "stream", or "external"') |
69 | unless $proto =~ m/^(icmp|udp|tcp|stream|external)$/; |
70 | $self->{"proto"} = $proto; |
71 | |
72 | $timeout = $def_timeout unless $timeout; # Determine the timeout |
73 | croak("Default timeout for ping must be greater than 0 seconds") |
74 | if $timeout <= 0; |
75 | $self->{"timeout"} = $timeout; |
76 | |
77 | $min_datasize = ($proto eq "udp") ? 1 : 0; # Determine data size |
78 | $data_size = $min_datasize unless defined($data_size) && $proto ne "tcp"; |
79 | croak("Data for ping must be from $min_datasize to $max_datasize bytes") |
80 | if ($data_size < $min_datasize) || ($data_size > $max_datasize); |
81 | $data_size-- if $self->{"proto"} eq "udp"; # We provide the first byte |
82 | $self->{"data_size"} = $data_size; |
83 | |
84 | $self->{"data"} = ""; # Construct data bytes |
85 | for ($cnt = 0; $cnt < $self->{"data_size"}; $cnt++) |
86 | { |
87 | $self->{"data"} .= chr($cnt % 256); |
88 | } |
89 | |
90 | $self->{"local_addr"} = undef; # Don't bind by default |
91 | |
92 | $self->{"seq"} = 0; # For counting packets |
93 | if ($self->{"proto"} eq "udp") # Open a socket |
94 | { |
95 | $self->{"proto_num"} = (getprotobyname('udp'))[2] || |
96 | croak("Can't udp protocol by name"); |
97 | $self->{"port_num"} = (getservbyname('echo', 'udp'))[2] || |
98 | croak("Can't get udp echo port by name"); |
99 | $self->{"fh"} = FileHandle->new(); |
100 | socket($self->{"fh"}, PF_INET, SOCK_DGRAM, |
101 | $self->{"proto_num"}) || |
102 | croak("udp socket error - $!"); |
103 | } |
104 | elsif ($self->{"proto"} eq "icmp") |
105 | { |
106 | croak("icmp ping requires root privilege") if ($> and $^O ne 'VMS'); |
107 | $self->{"proto_num"} = (getprotobyname('icmp'))[2] || |
108 | croak("Can't get icmp protocol by name"); |
109 | $self->{"pid"} = $$ & 0xffff; # Save lower 16 bits of pid |
110 | $self->{"fh"} = FileHandle->new(); |
111 | socket($self->{"fh"}, PF_INET, SOCK_RAW, $self->{"proto_num"}) || |
112 | croak("icmp socket error - $!"); |
113 | } |
114 | elsif ($self->{"proto"} eq "tcp" || $self->{"proto"} eq "stream") |
115 | { |
116 | $self->{"proto_num"} = (getprotobyname('tcp'))[2] || |
117 | croak("Can't get tcp protocol by name"); |
118 | $self->{"port_num"} = (getservbyname('echo', 'tcp'))[2] || |
119 | croak("Can't get tcp echo port by name"); |
120 | $self->{"fh"} = FileHandle->new(); |
121 | } |
122 | |
123 | return($self); |
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124 | } |
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125 | |
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126 | # Description: Set the local IP address from which pings will be sent. |
127 | # For ICMP and UDP pings, this calls bind() on the already-opened socket; |
128 | # for TCP pings, just saves the address to be used when the socket is |
129 | # opened. Returns non-zero if successful; croaks on error. |
130 | sub bind |
131 | { |
e82f584b |
132 | my ($self, |
133 | $local_addr # Name or IP number of local interface |
134 | ) = @_; |
135 | my ($ip # Packed IP number of $local_addr |
136 | ); |
137 | |
138 | croak("Usage: \$p->bind(\$local_addr)") unless @_ == 2; |
139 | croak("already bound") if defined($self->{"local_addr"}) && |
140 | ($self->{"proto"} eq "udp" || $self->{"proto"} eq "icmp"); |
141 | |
142 | $ip = inet_aton($local_addr); |
143 | croak("nonexistent local address $local_addr") unless defined($ip); |
144 | $self->{"local_addr"} = $ip; # Only used if proto is tcp |
145 | |
146 | if ($self->{"proto"} eq "udp" || $self->{"proto"} eq "icmp") |
147 | { |
148 | CORE::bind($self->{"fh"}, sockaddr_in(0, $ip)) || |
149 | croak("$self->{'proto'} bind error - $!"); |
150 | } |
151 | elsif ($self->{"proto"} ne "tcp") |
152 | { |
153 | croak("Unknown protocol \"$self->{proto}\" in bind()"); |
154 | } |
155 | |
156 | return 1; |
157 | } |
49afa5f6 |
158 | |
49afa5f6 |
159 | |
e82f584b |
160 | # Description: allows the module to use milliseconds as returned by |
161 | # the Time::HiRes module |
49afa5f6 |
162 | |
e82f584b |
163 | $hires = 0; |
164 | sub hires |
165 | { |
166 | my $self = shift; |
167 | $hires = 1 unless defined |
168 | ($hires = ((defined $self) && (ref $self)) ? shift() : $self); |
169 | require Time::HiRes if $hires; |
49afa5f6 |
170 | } |
171 | |
e82f584b |
172 | sub time |
173 | { |
174 | return $hires ? Time::HiRes::time() : CORE::time(); |
175 | } |
49afa5f6 |
176 | |
a3b93737 |
177 | # Description: Ping a host name or IP number with an optional timeout. |
178 | # First lookup the host, and return undef if it is not found. Otherwise |
b124990b |
179 | # perform the specific ping method based on the protocol. Return the |
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180 | # result of the ping. |
181 | |
182 | sub ping |
183 | { |
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184 | my ($self, |
185 | $host, # Name or IP number of host to ping |
186 | $timeout, # Seconds after which ping times out |
187 | ) = @_; |
188 | my ($ip, # Packed IP number of $host |
189 | $ret, # The return value |
190 | $ping_time, # When ping began |
191 | ); |
192 | |
193 | croak("Usage: \$p->ping(\$host [, \$timeout])") unless @_ == 2 || @_ == 3; |
194 | $timeout = $self->{"timeout"} unless $timeout; |
195 | croak("Timeout must be greater than 0 seconds") if $timeout <= 0; |
196 | |
197 | $ip = inet_aton($host); |
198 | return(undef) unless defined($ip); # Does host exist? |
199 | |
200 | # Dispatch to the appropriate routine. |
201 | $ping_time = &time(); |
202 | if ($self->{"proto"} eq "external") { |
203 | $ret = $self->ping_external($ip, $timeout); |
204 | } |
205 | elsif ($self->{"proto"} eq "udp") { |
206 | $ret = $self->ping_udp($ip, $timeout); |
207 | } |
208 | elsif ($self->{"proto"} eq "icmp") { |
209 | $ret = $self->ping_icmp($ip, $timeout); |
210 | } |
211 | elsif ($self->{"proto"} eq "tcp") { |
212 | $ret = $self->ping_tcp($ip, $timeout); |
213 | } |
214 | elsif ($self->{"proto"} eq "stream") { |
215 | $ret = $self->ping_stream($ip, $timeout); |
216 | } else { |
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217 | croak("Unknown protocol \"$self->{proto}\" in ping()"); |
e82f584b |
218 | } |
219 | |
220 | return wantarray ? ($ret, &time() - $ping_time, inet_ntoa($ip)) : $ret; |
787ecdfa |
221 | } |
222 | |
223 | # Uses Net::Ping::External to do an external ping. |
224 | sub ping_external { |
225 | my ($self, |
226 | $ip, # Packed IP number of the host |
227 | $timeout # Seconds after which ping times out |
228 | ) = @_; |
229 | |
b124990b |
230 | eval { require Net::Ping::External; } |
231 | or croak('Protocol "external" not supported on your system: Net::Ping::External not found'); |
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232 | return Net::Ping::External::ping(ip => $ip, timeout => $timeout); |
a3b93737 |
233 | } |
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234 | |
49afa5f6 |
235 | use constant ICMP_ECHOREPLY => 0; # ICMP packet types |
236 | use constant ICMP_ECHO => 8; |
237 | use constant ICMP_STRUCT => "C2 S3 A"; # Structure of a minimal ICMP packet |
238 | use constant SUBCODE => 0; # No ICMP subcode for ECHO and ECHOREPLY |
239 | use constant ICMP_FLAGS => 0; # No special flags for send or recv |
240 | use constant ICMP_PORT => 0; # No port with ICMP |
241 | |
a3b93737 |
242 | sub ping_icmp |
243 | { |
e82f584b |
244 | my ($self, |
245 | $ip, # Packed IP number of the host |
246 | $timeout # Seconds after which ping times out |
247 | ) = @_; |
248 | |
249 | my ($saddr, # sockaddr_in with port and ip |
250 | $checksum, # Checksum of ICMP packet |
251 | $msg, # ICMP packet to send |
252 | $len_msg, # Length of $msg |
253 | $rbits, # Read bits, filehandles for reading |
254 | $nfound, # Number of ready filehandles found |
255 | $finish_time, # Time ping should be finished |
256 | $done, # set to 1 when we are done |
257 | $ret, # Return value |
258 | $recv_msg, # Received message including IP header |
259 | $from_saddr, # sockaddr_in of sender |
260 | $from_port, # Port packet was sent from |
261 | $from_ip, # Packed IP of sender |
262 | $from_type, # ICMP type |
263 | $from_subcode, # ICMP subcode |
264 | $from_chk, # ICMP packet checksum |
265 | $from_pid, # ICMP packet id |
266 | $from_seq, # ICMP packet sequence |
267 | $from_msg # ICMP message |
268 | ); |
269 | |
270 | $self->{"seq"} = ($self->{"seq"} + 1) % 65536; # Increment sequence |
271 | $checksum = 0; # No checksum for starters |
272 | $msg = pack(ICMP_STRUCT . $self->{"data_size"}, ICMP_ECHO, SUBCODE, |
273 | $checksum, $self->{"pid"}, $self->{"seq"}, $self->{"data"}); |
274 | $checksum = Net::Ping->checksum($msg); |
275 | $msg = pack(ICMP_STRUCT . $self->{"data_size"}, ICMP_ECHO, SUBCODE, |
276 | $checksum, $self->{"pid"}, $self->{"seq"}, $self->{"data"}); |
277 | $len_msg = length($msg); |
278 | $saddr = sockaddr_in(ICMP_PORT, $ip); |
279 | send($self->{"fh"}, $msg, ICMP_FLAGS, $saddr); # Send the message |
280 | |
281 | $rbits = ""; |
282 | vec($rbits, $self->{"fh"}->fileno(), 1) = 1; |
283 | $ret = 0; |
284 | $done = 0; |
285 | $finish_time = &time() + $timeout; # Must be done by this time |
286 | while (!$done && $timeout > 0) # Keep trying if we have time |
287 | { |
288 | $nfound = select($rbits, undef, undef, $timeout); # Wait for packet |
289 | $timeout = $finish_time - &time(); # Get remaining time |
290 | if (!defined($nfound)) # Hmm, a strange error |
a3b93737 |
291 | { |
e82f584b |
292 | $ret = undef; |
293 | $done = 1; |
294 | } |
295 | elsif ($nfound) # Got a packet from somewhere |
296 | { |
297 | $recv_msg = ""; |
298 | $from_saddr = recv($self->{"fh"}, $recv_msg, 1500, ICMP_FLAGS); |
299 | ($from_port, $from_ip) = sockaddr_in($from_saddr); |
300 | ($from_type, $from_subcode, $from_chk, |
301 | $from_pid, $from_seq, $from_msg) = |
302 | unpack(ICMP_STRUCT . $self->{"data_size"}, |
303 | substr($recv_msg, length($recv_msg) - $len_msg, |
304 | $len_msg)); |
305 | if (($from_type == ICMP_ECHOREPLY) && |
306 | ($from_ip eq $ip) && |
307 | ($from_pid == $self->{"pid"}) && # Does the packet check out? |
308 | ($from_seq == $self->{"seq"})) |
309 | { |
310 | $ret = 1; # It's a winner |
311 | $done = 1; |
312 | } |
a3b93737 |
313 | } |
e82f584b |
314 | else # Oops, timed out |
315 | { |
316 | $done = 1; |
317 | } |
318 | } |
319 | return $ret; |
a3b93737 |
320 | } |
321 | |
322 | # Description: Do a checksum on the message. Basically sum all of |
323 | # the short words and fold the high order bits into the low order bits. |
324 | |
325 | sub checksum |
326 | { |
e82f584b |
327 | my ($class, |
328 | $msg # The message to checksum |
329 | ) = @_; |
330 | my ($len_msg, # Length of the message |
331 | $num_short, # The number of short words in the message |
332 | $short, # One short word |
333 | $chk # The checksum |
334 | ); |
335 | |
336 | $len_msg = length($msg); |
337 | $num_short = int($len_msg / 2); |
338 | $chk = 0; |
339 | foreach $short (unpack("S$num_short", $msg)) |
340 | { |
341 | $chk += $short; |
342 | } # Add the odd byte in |
343 | $chk += (unpack("C", substr($msg, $len_msg - 1, 1)) << 8) if $len_msg % 2; |
344 | $chk = ($chk >> 16) + ($chk & 0xffff); # Fold high into low |
345 | return(~(($chk >> 16) + $chk) & 0xffff); # Again and complement |
a3b93737 |
346 | } |
347 | |
787ecdfa |
348 | |
b124990b |
349 | # Description: Perform a tcp echo ping. Since a tcp connection is |
350 | # host specific, we have to open and close each connection here. We |
351 | # can't just leave a socket open. Because of the robust nature of |
352 | # tcp, it will take a while before it gives up trying to establish a |
353 | # connection. Therefore, we use select() on a non-blocking socket to |
354 | # check against our timeout. No data bytes are actually |
355 | # sent since the successful establishment of a connection is proof |
356 | # enough of the reachability of the remote host. Also, tcp is |
357 | # expensive and doesn't need our help to add to the overhead. |
358 | |
359 | sub ping_tcp |
787ecdfa |
360 | { |
e82f584b |
361 | my ($self, |
362 | $ip, # Packed IP number of the host |
363 | $timeout # Seconds after which ping times out |
364 | ) = @_; |
365 | my ($ret # The return value |
366 | ); |
367 | |
368 | $@ = ""; $! = 0; |
369 | $ret = $self -> tcp_connect( $ip, $timeout); |
370 | $ret = 1 if $! == ECONNREFUSED # Connection refused |
371 | || $@ =~ /Unknown Error/i; # Special Win32 response? |
372 | $self->{"fh"}->close(); |
373 | return $ret; |
787ecdfa |
374 | } |
375 | |
b124990b |
376 | sub tcp_connect |
787ecdfa |
377 | { |
e82f584b |
378 | my ($self, |
379 | $ip, # Packed IP number of the host |
380 | $timeout # Seconds after which connect times out |
381 | ) = @_; |
382 | my ($saddr); # Packed IP and Port |
b124990b |
383 | |
e82f584b |
384 | $saddr = sockaddr_in($self->{"port_num"}, $ip); |
b124990b |
385 | |
e82f584b |
386 | my $ret = 0; # Default to unreachable |
b124990b |
387 | |
e82f584b |
388 | my $do_socket = sub { |
389 | socket($self->{"fh"}, PF_INET, SOCK_STREAM, $self->{"proto_num"}) || |
390 | croak("tcp socket error - $!"); |
391 | if (defined $self->{"local_addr"} && |
392 | !CORE::bind($self->{"fh"}, sockaddr_in(0, $self->{"local_addr"}))) { |
393 | croak("tcp bind error - $!"); |
394 | } |
395 | }; |
396 | my $do_connect = sub { |
397 | eval { |
398 | die $! unless connect($self->{"fh"}, $saddr); |
399 | $self->{"ip"} = $ip; |
400 | $ret = 1; |
401 | }; |
402 | $ret; |
403 | }; |
404 | |
405 | if ($^O =~ /Win32/i) { |
406 | |
407 | # Buggy Winsock API doesn't allow us to use alarm() calls. |
408 | # Hence, if our OS is Windows, we need to create a separate |
409 | # process to do the blocking connect attempt. |
410 | |
411 | $| = 1; # Clear buffer prior to fork to prevent duplicate flushing. |
412 | my $pid = fork; |
413 | if (!$pid) { |
414 | if (!defined $pid) { |
415 | # Fork did not work |
416 | warn "Win32 Fork error: $!"; |
417 | return 0; |
b124990b |
418 | } |
b124990b |
419 | &{ $do_socket }(); |
420 | |
e82f584b |
421 | # Try a slow blocking connect() call |
422 | # and report the status to the pipe. |
423 | if ( &{ $do_connect }() ) { |
424 | $self->{"fh"}->close(); |
425 | # No error |
426 | exit 0; |
b124990b |
427 | } else { |
e82f584b |
428 | # Pass the error status to the parent |
429 | exit $!; |
b124990b |
430 | } |
e82f584b |
431 | } |
b124990b |
432 | |
e82f584b |
433 | &{ $do_socket }(); |
434 | |
435 | my $patience = &time() + $timeout; |
436 | |
437 | require POSIX; |
438 | my ($child); |
439 | $? = 0; |
440 | # Wait up to the timeout |
441 | # And clean off the zombie |
442 | do { |
443 | $child = waitpid($pid, &POSIX::WNOHANG); |
444 | $! = $? >> 8; |
445 | $@ = $!; |
446 | select(undef, undef, undef, 0.1); |
447 | } while &time() < $patience && $child != $pid; |
448 | |
449 | if ($child == $pid) { |
450 | # Since she finished within the timeout, |
451 | # it is probably safe for me to try it too |
b124990b |
452 | &{ $do_connect }(); |
e82f584b |
453 | } else { |
454 | # Time must have run out. |
455 | $@ = "Timed out!"; |
456 | # Put that choking client out of its misery |
457 | kill "KILL", $pid; |
458 | # Clean off the zombie |
459 | waitpid($pid, 0); |
460 | $ret = 0; |
b124990b |
461 | } |
e82f584b |
462 | } else { # Win32 |
463 | # Otherwise don't waste the resources to fork |
464 | |
465 | &{ $do_socket }(); |
466 | |
467 | $SIG{'ALRM'} = sub { die "Timed out!"; }; |
468 | alarm($timeout); # Interrupt connect() if we have to |
469 | |
470 | &{ $do_connect }(); |
471 | alarm(0); |
472 | } |
787ecdfa |
473 | |
e82f584b |
474 | return $ret; |
787ecdfa |
475 | } |
476 | |
477 | # This writes the given string to the socket and then reads it |
478 | # back. It returns 1 on success, 0 on failure. |
479 | sub tcp_echo |
480 | { |
e82f584b |
481 | my $self = shift; |
482 | my $timeout = shift; |
483 | my $pingstring = shift; |
484 | |
485 | my $ret = undef; |
486 | my $time = &time(); |
487 | my $wrstr = $pingstring; |
488 | my $rdstr = ""; |
489 | |
490 | eval <<'EOM'; |
491 | do { |
492 | my $rin = ""; |
493 | vec($rin, $self->{"fh"}->fileno(), 1) = 1; |
494 | |
495 | my $rout = undef; |
496 | if($wrstr) { |
497 | $rout = ""; |
498 | vec($rout, $self->{"fh"}->fileno(), 1) = 1; |
499 | } |
500 | |
501 | if(select($rin, $rout, undef, ($time + $timeout) - &time())) { |
502 | |
503 | if($rout && vec($rout,$self->{"fh"}->fileno(),1)) { |
504 | my $num = syswrite($self->{"fh"}, $wrstr); |
505 | if($num) { |
506 | # If it was a partial write, update and try again. |
507 | $wrstr = substr($wrstr,$num); |
508 | } else { |
509 | # There was an error. |
510 | $ret = 0; |
511 | } |
512 | } |
513 | |
514 | if(vec($rin,$self->{"fh"}->fileno(),1)) { |
515 | my $reply; |
516 | if(sysread($self->{"fh"},$reply,length($pingstring)-length($rdstr))) { |
517 | $rdstr .= $reply; |
518 | $ret = 1 if $rdstr eq $pingstring; |
519 | } else { |
520 | # There was an error. |
521 | $ret = 0; |
522 | } |
523 | } |
524 | |
525 | } |
526 | } until &time() > ($time + $timeout) || defined($ret); |
787ecdfa |
527 | EOM |
528 | |
e82f584b |
529 | return $ret; |
787ecdfa |
530 | } |
531 | |
787ecdfa |
532 | |
787ecdfa |
533 | |
787ecdfa |
534 | |
535 | # Description: Perform a stream ping. If the tcp connection isn't |
536 | # already open, it opens it. It then sends some data and waits for |
537 | # a reply. It leaves the stream open on exit. |
538 | |
539 | sub ping_stream |
540 | { |
e82f584b |
541 | my ($self, |
542 | $ip, # Packed IP number of the host |
543 | $timeout # Seconds after which ping times out |
544 | ) = @_; |
072620d9 |
545 | |
e82f584b |
546 | # Open the stream if it's not already open |
547 | if(!defined $self->{"fh"}->fileno()) { |
548 | $self->tcp_connect($ip, $timeout) or return 0; |
549 | } |
787ecdfa |
550 | |
e82f584b |
551 | croak "tried to switch servers while stream pinging" |
552 | if $self->{"ip"} ne $ip; |
553 | |
554 | return $self->tcp_echo($timeout, $pingstring); |
787ecdfa |
555 | } |
556 | |
557 | # Description: opens the stream. You would do this if you want to |
558 | # separate the overhead of opening the stream from the first ping. |
559 | |
560 | sub open |
561 | { |
e82f584b |
562 | my ($self, |
563 | $host, # Host or IP address |
564 | $timeout # Seconds after which open times out |
565 | ) = @_; |
566 | |
567 | my ($ip); # Packed IP number of the host |
568 | $ip = inet_aton($host); |
569 | $timeout = $self->{"timeout"} unless $timeout; |
570 | |
571 | if($self->{"proto"} eq "stream") { |
572 | if(defined($self->{"fh"}->fileno())) { |
573 | croak("socket is already open"); |
574 | } else { |
575 | $self->tcp_connect($ip, $timeout); |
b124990b |
576 | } |
e82f584b |
577 | } |
072620d9 |
578 | } |
579 | |
b124990b |
580 | |
a3b93737 |
581 | # Description: Perform a udp echo ping. Construct a message of |
582 | # at least the one-byte sequence number and any additional data bytes. |
583 | # Send the message out and wait for a message to come back. If we |
584 | # get a message, make sure all of its parts match. If they do, we are |
585 | # done. Otherwise go back and wait for the message until we run out |
586 | # of time. Return the result of our efforts. |
587 | |
49afa5f6 |
588 | use constant UDP_FLAGS => 0; # Nothing special on send or recv |
589 | |
a3b93737 |
590 | sub ping_udp |
591 | { |
e82f584b |
592 | my ($self, |
593 | $ip, # Packed IP number of the host |
594 | $timeout # Seconds after which ping times out |
595 | ) = @_; |
596 | |
597 | my ($saddr, # sockaddr_in with port and ip |
598 | $ret, # The return value |
599 | $msg, # Message to be echoed |
600 | $finish_time, # Time ping should be finished |
601 | $ping_time, # Time ping took to complete |
602 | $done, # Set to 1 when we are done pinging |
603 | $rbits, # Read bits, filehandles for reading |
604 | $nfound, # Number of ready filehandles found |
605 | $from_saddr, # sockaddr_in of sender |
606 | $from_msg, # Characters echoed by $host |
607 | $from_port, # Port message was echoed from |
608 | $from_ip # Packed IP number of sender |
609 | ); |
610 | |
611 | $saddr = sockaddr_in($self->{"port_num"}, $ip); |
612 | $self->{"seq"} = ($self->{"seq"} + 1) % 256; # Increment sequence |
613 | $msg = chr($self->{"seq"}) . $self->{"data"}; # Add data if any |
614 | send($self->{"fh"}, $msg, UDP_FLAGS, $saddr); # Send it |
615 | |
616 | $rbits = ""; |
617 | vec($rbits, $self->{"fh"}->fileno(), 1) = 1; |
618 | $ret = 0; # Default to unreachable |
619 | $done = 0; |
620 | $ping_time = $timeout; |
621 | $finish_time = &time() + $timeout; # Ping needs to be done by then |
622 | while (!$done && $timeout > 0) |
623 | { |
624 | $nfound = select($rbits, undef, undef, $timeout); # Wait for response |
625 | $timeout = $finish_time - &time(); # Get remaining time |
626 | |
627 | if (!defined($nfound)) # Hmm, a strange error |
a3b93737 |
628 | { |
e82f584b |
629 | $ret = undef; |
630 | $done = 1; |
a3b93737 |
631 | } |
e82f584b |
632 | elsif ($nfound) # A packet is waiting |
633 | { |
634 | $from_msg = ""; |
635 | $from_saddr = recv($self->{"fh"}, $from_msg, 1500, UDP_FLAGS) |
636 | or last; # For example an unreachable host will make recv() fail. |
637 | ($from_port, $from_ip) = sockaddr_in($from_saddr); |
638 | if (($from_ip eq $ip) && # Does the packet check out? |
639 | ($from_port == $self->{"port_num"}) && |
640 | ($from_msg eq $msg)) |
641 | { |
642 | $ret = 1; # It's a winner |
643 | $done = 1; |
644 | } |
645 | } |
646 | else # Oops, timed out |
647 | { |
648 | $done = 1; |
649 | } |
650 | } |
651 | $ping_time -= $timeout; |
652 | return wantarray ? ($ret, $ping_time) : $ret; |
b124990b |
653 | } |
a0d0e21e |
654 | |
a3b93737 |
655 | # Description: Close the connection unless we are using the tcp |
656 | # protocol, since it will already be closed. |
657 | |
658 | sub close |
659 | { |
e82f584b |
660 | my ($self) = @_; |
a3b93737 |
661 | |
e82f584b |
662 | $self->{"fh"}->close() unless $self->{"proto"} eq "tcp"; |
a3b93737 |
663 | } |
664 | |
665 | |
a0d0e21e |
666 | 1; |
8e07c86e |
667 | __END__ |
668 | |
8e07c86e |
669 | =head1 NAME |
670 | |
a3b93737 |
671 | Net::Ping - check a remote host for reachability |
8e07c86e |
672 | |
e82f584b |
673 | $Id: Ping.pm,v 1.27 2002/04/02 02:01:21 rob Exp $ |
b124990b |
674 | |
8e07c86e |
675 | =head1 SYNOPSIS |
676 | |
677 | use Net::Ping; |
8e07c86e |
678 | |
a3b93737 |
679 | $p = Net::Ping->new(); |
680 | print "$host is alive.\n" if $p->ping($host); |
681 | $p->close(); |
682 | |
683 | $p = Net::Ping->new("icmp"); |
49afa5f6 |
684 | $p->bind($my_addr); # Specify source interface of pings |
a3b93737 |
685 | foreach $host (@host_array) |
686 | { |
687 | print "$host is "; |
688 | print "NOT " unless $p->ping($host, 2); |
689 | print "reachable.\n"; |
690 | sleep(1); |
691 | } |
692 | $p->close(); |
b124990b |
693 | |
a3b93737 |
694 | $p = Net::Ping->new("tcp", 2); |
b124990b |
695 | # Try connecting to the www port instead of the echo port |
696 | $p->{port_num} = getservbyname("http", "tcp"); |
a3b93737 |
697 | while ($stop_time > time()) |
698 | { |
699 | print "$host not reachable ", scalar(localtime()), "\n" |
700 | unless $p->ping($host); |
701 | sleep(300); |
702 | } |
703 | undef($p); |
b124990b |
704 | |
e82f584b |
705 | # High precision syntax (requires Time::HiRes) |
706 | $p = Net::Ping->new(); |
707 | $p->hires(); |
708 | ($ret, $duration, $ip) = $p->ping($host, 5.5); |
709 | printf("$host [ip: $ip] is alive (packet return time: %.2f ms)\n", 1000 * $duration) |
710 | if $ret; |
711 | $p->close(); |
712 | |
a3b93737 |
713 | # For backward compatibility |
714 | print "$host is alive.\n" if pingecho($host); |
8e07c86e |
715 | |
a3b93737 |
716 | =head1 DESCRIPTION |
8e07c86e |
717 | |
a3b93737 |
718 | This module contains methods to test the reachability of remote |
719 | hosts on a network. A ping object is first created with optional |
720 | parameters, a variable number of hosts may be pinged multiple |
721 | times and then the connection is closed. |
722 | |
b124990b |
723 | You may choose one of four different protocols to use for the |
724 | ping. The "udp" protocol is the default. Note that a live remote host |
725 | may still fail to be pingable by one or more of these protocols. For |
726 | example, www.microsoft.com is generally alive but not pingable. |
787ecdfa |
727 | |
b124990b |
728 | With the "tcp" protocol the ping() method attempts to establish a |
729 | connection to the remote host's echo port. If the connection is |
730 | successfully established, the remote host is considered reachable. No |
731 | data is actually echoed. This protocol does not require any special |
732 | privileges but has higher overhead than the other two protocols. |
072620d9 |
733 | |
b124990b |
734 | Specifying the "udp" protocol causes the ping() method to send a udp |
a3b93737 |
735 | packet to the remote host's echo port. If the echoed packet is |
736 | received from the remote host and the received packet contains the |
737 | same data as the packet that was sent, the remote host is considered |
738 | reachable. This protocol does not require any special privileges. |
b124990b |
739 | It should be borne in mind that, for a udp ping, a host |
787ecdfa |
740 | will be reported as unreachable if it is not running the |
b124990b |
741 | appropriate echo service. For Unix-like systems see L<inetd(8)> |
742 | for more information. |
787ecdfa |
743 | |
b124990b |
744 | If the "icmp" protocol is specified, the ping() method sends an icmp |
745 | echo message to the remote host, which is what the UNIX ping program |
746 | does. If the echoed message is received from the remote host and |
747 | the echoed information is correct, the remote host is considered |
748 | reachable. Specifying the "icmp" protocol requires that the program |
749 | be run as root or that the program be setuid to root. |
787ecdfa |
750 | |
b124990b |
751 | If the "external" protocol is specified, the ping() method attempts to |
752 | use the C<Net::Ping::External> module to ping the remote host. |
753 | C<Net::Ping::External> interfaces with your system's default C<ping> |
754 | utility to perform the ping, and generally produces relatively |
787ecdfa |
755 | accurate results. If C<Net::Ping::External> if not installed on your |
756 | system, specifying the "external" protocol will result in an error. |
edc5bd88 |
757 | |
a3b93737 |
758 | =head2 Functions |
759 | |
760 | =over 4 |
761 | |
762 | =item Net::Ping->new([$proto [, $def_timeout [, $bytes]]]); |
763 | |
764 | Create a new ping object. All of the parameters are optional. $proto |
765 | specifies the protocol to use when doing a ping. The current choices |
766 | are "tcp", "udp" or "icmp". The default is "udp". |
767 | |
768 | If a default timeout ($def_timeout) in seconds is provided, it is used |
769 | when a timeout is not given to the ping() method (below). The timeout |
770 | must be greater than 0 and the default, if not specified, is 5 seconds. |
771 | |
772 | If the number of data bytes ($bytes) is given, that many data bytes |
773 | are included in the ping packet sent to the remote host. The number of |
774 | data bytes is ignored if the protocol is "tcp". The minimum (and |
775 | default) number of data bytes is 1 if the protocol is "udp" and 0 |
776 | otherwise. The maximum number of data bytes that can be specified is |
777 | 1024. |
778 | |
e82f584b |
779 | =item $p->hires( { 0 | 1 } ); |
780 | |
781 | Causes this module to use Time::HiRes module, allowing milliseconds |
782 | to be returned by subsequent calls to ping(). |
783 | |
49afa5f6 |
784 | =item $p->bind($local_addr); |
785 | |
786 | Sets the source address from which pings will be sent. This must be |
787 | the address of one of the interfaces on the local host. $local_addr |
788 | may be specified as a hostname or as a text IP address such as |
789 | "192.168.1.1". |
790 | |
791 | If the protocol is set to "tcp", this method may be called any |
792 | number of times, and each call to the ping() method (below) will use |
793 | the most recent $local_addr. If the protocol is "icmp" or "udp", |
794 | then bind() must be called at most once per object, and (if it is |
795 | called at all) must be called before the first call to ping() for that |
796 | object. |
797 | |
a3b93737 |
798 | =item $p->ping($host [, $timeout]); |
799 | |
800 | Ping the remote host and wait for a response. $host can be either the |
801 | hostname or the IP number of the remote host. The optional timeout |
802 | must be greater than 0 seconds and defaults to whatever was specified |
e82f584b |
803 | when the ping object was created. Returns a success flag. If the |
804 | hostname cannot be found or there is a problem with the IP number, the |
805 | success flag returned will be undef. Otherwise, the success flag will |
806 | be 1 if the host is reachable and 0 if it is not. For most practical |
807 | purposes, undef and 0 and can be treated as the same case. In array |
808 | context, the elapsed time is also returned. The elapsed time value will |
809 | be a float, as retuned by the Time::HiRes::time() function, if hires() |
810 | has been previously called, otherwise it is returned as an integer. |
b124990b |
811 | |
812 | =item $p->open($host); |
813 | |
814 | When you are using the stream protocol, this call pre-opens the |
815 | tcp socket. It's only necessary to do this if you want to |
816 | provide a different timeout when creating the connection, or |
817 | remove the overhead of establishing the connection from the |
818 | first ping. If you don't call C<open()>, the connection is |
819 | automatically opened the first time C<ping()> is called. |
787ecdfa |
820 | This call simply does nothing if you are using any protocol other |
821 | than stream. |
822 | |
a3b93737 |
823 | =item $p->close(); |
824 | |
825 | Close the network connection for this ping object. The network |
826 | connection is also closed by "undef $p". The network connection is |
827 | automatically closed if the ping object goes out of scope (e.g. $p is |
828 | local to a subroutine and you leave the subroutine). |
829 | |
830 | =item pingecho($host [, $timeout]); |
831 | |
832 | To provide backward compatibility with the previous version of |
833 | Net::Ping, a pingecho() subroutine is available with the same |
834 | functionality as before. pingecho() uses the tcp protocol. The |
835 | return values and parameters are the same as described for the ping() |
836 | method. This subroutine is obsolete and may be removed in a future |
837 | version of Net::Ping. |
8e07c86e |
838 | |
a3b93737 |
839 | =back |
8e07c86e |
840 | |
b124990b |
841 | =head1 WARNING |
842 | |
843 | pingecho() or a ping object with the tcp protocol use alarm() to |
844 | implement the timeout. So, don't use alarm() in your program while |
845 | you are using pingecho() or a ping object with the tcp protocol. The |
846 | udp and icmp protocols do not use alarm() to implement the timeout. |
847 | |
a3b93737 |
848 | =head1 NOTES |
8e07c86e |
849 | |
a3b93737 |
850 | There will be less network overhead (and some efficiency in your |
851 | program) if you specify either the udp or the icmp protocol. The tcp |
852 | protocol will generate 2.5 times or more traffic for each ping than |
853 | either udp or icmp. If many hosts are pinged frequently, you may wish |
854 | to implement a small wait (e.g. 25ms or more) between each ping to |
855 | avoid flooding your network with packets. |
8e07c86e |
856 | |
a3b93737 |
857 | The icmp protocol requires that the program be run as root or that it |
787ecdfa |
858 | be setuid to root. The other protocols do not require special |
859 | privileges, but not all network devices implement tcp or udp echo. |
8e07c86e |
860 | |
a3b93737 |
861 | Local hosts should normally respond to pings within milliseconds. |
862 | However, on a very congested network it may take up to 3 seconds or |
863 | longer to receive an echo packet from the remote host. If the timeout |
864 | is set too low under these conditions, it will appear that the remote |
865 | host is not reachable (which is almost the truth). |
8e07c86e |
866 | |
a3b93737 |
867 | Reachability doesn't necessarily mean that the remote host is actually |
787ecdfa |
868 | functioning beyond its ability to echo packets. tcp is slightly better |
869 | at indicating the health of a system than icmp because it uses more |
870 | of the networking stack to respond. |
8e07c86e |
871 | |
a3b93737 |
872 | Because of a lack of anything better, this module uses its own |
873 | routines to pack and unpack ICMP packets. It would be better for a |
874 | separate module to be written which understands all of the different |
875 | kinds of ICMP packets. |
8e07c86e |
876 | |
49afa5f6 |
877 | =head1 AUTHORS |
b124990b |
878 | |
e82f584b |
879 | Current maintainer: |
49afa5f6 |
880 | bbb@cpan.org (Rob Brown) |
b124990b |
881 | |
e82f584b |
882 | External protocol: |
883 | colinm@cpan.org (Colin McMillen) |
884 | |
b124990b |
885 | Stream protocol: |
886 | bronson@trestle.com (Scott Bronson) |
887 | |
888 | Original pingecho(): |
889 | karrer@bernina.ethz.ch (Andreas Karrer) |
890 | pmarquess@bfsec.bt.co.uk (Paul Marquess) |
891 | |
892 | Original Net::Ping author: |
893 | mose@ns.ccsn.edu (Russell Mosemann) |
894 | |
b124990b |
895 | =head1 COPYRIGHT |
896 | |
e82f584b |
897 | Copyright (c) 2002, Rob Brown. All rights reserved. |
49afa5f6 |
898 | |
e82f584b |
899 | Copyright (c) 2001, Colin McMillen. All rights reserved. |
b124990b |
900 | |
901 | This program is free software; you may redistribute it and/or |
902 | modify it under the same terms as Perl itself. |
903 | |
a3b93737 |
904 | =cut |