1#!/usr/bin/perl 2 3# dnslist - Read state file from dnsmasq and create a nice web page to display 4# a list of DHCP clients. 5# 6# Copyright (C) 2004 Thomas Tuttle 7# 8# This program is free software; you can redistribute it and/or modify 9# it under the terms of the GNU General Public License as published by 10# the Free Software Foundation; either version 2 of the License, or 11# (at your option) any later version. 12# 13# This program is distributed in the hope that it will be useful, 14# but WITHOUT ANY WARRANTY; without even the implied warranty of 15# MERCHANTIBILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16# GNU General Public License for more details. 17# 18# You should have received a copy of the GNU General Public License 19# along with this program*; if not, write to the Free Software 20# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21# 22# * The license is in fact included at the end of this file, and can 23# either be viewed by reading everything after "__DATA__" or by 24# running dnslist with the '-l' option. 25# 26# Version: 0.2 27# Author: Thomas Tuttle 28# Email: dnslist.20.thinkinginbinary@spamgourmet.org 29# License: GNU General Public License, version 2.0 30# 31# v. 0.0: Too ugly to publish, thrown out. 32# 33# v. 0.1: First rewrite. 34# Added master host list so offline hosts can still be displayed. 35# Fixed modification detection (a newer modification time is lower.) 36# 37# v. 0.2: Fixed Client ID = "*" => "None" 38# Fixed HTML entities (a client ID of ????<? screwed it up) 39# Fixed command-line argument processing (apparently, "shift @ARGV" != 40# "$_ = shift @ARGV"...) 41# Added license information. 42 43use Template; 44 45# Location of state file. (This is the dnsmasq default.) 46# Change with -s <file> 47my $dnsmasq_state_file = '/var/lib/misc/dnsmasq.leases'; 48# Location of template. (Assumed to be in current directory.) 49# Change with -t <file> 50my $html_template_file = 'dnslist.tt2'; 51# File to write HTML page to. (This is where Slackware puts WWW pages. It may 52# be different on other systems. Make sure the permissions are set correctly 53# for it.) 54my $html_output_file = '/var/www/htdocs/dhcp.html'; 55# Time to wait after each page update. (The state file is checked for changes 56# before each update but is not read in each time, in case it is very big. The 57# page is rewritten just so the "(updated __/__ __:__:__)" text changes ;-) 58my $wait_time = 2; 59 60# Read command-line arguments. 61while ($_ = shift @ARGV) { 62 if (/-s/) { $dnsmasq_state_file = shift; next; } 63 if (/-t/) { $html_template_file = shift; next; } 64 if (/-o/) { $html_output_file = shift; next; } 65 if (/-d/) { $wait_time = shift; next; } 66 if (/-l/) { show_license(); exit; } 67 die "usage: dnslist [-s state_file] [-t template_file] [-o output_file] [-d delay_time]\n"; 68} 69 70# Master list of clients, offline and online. 71my $list = {}; 72# Sorted host list. (It's actually sorted by IP--the sub &byip() compares two 73# IP addresses, octet by octet, and figures out which is higher.) 74my @hosts = (); 75# Last time the state file was changed. 76my $last_state_change; 77 78# Check for a change to the state file. 79sub check_state { 80 if (defined $last_state_change) { 81 if (-M $dnsmasq_state_file < $last_state_change) { 82 print "check_state: state file has been changed.\n"; 83 $last_state_change = -M $dnsmasq_state_file; 84 return 1; 85 } else { 86 return 0; 87 } 88 } else { 89 # Last change undefined, so we are running for the first time. 90 print "check_state: reading state file at startup.\n"; 91 read_state(); 92 $last_state_change = -M $dnsmasq_state_file; 93 return 1; 94 } 95} 96 97# Read data in state file. 98sub read_state { 99 my $old; 100 my $new; 101 # Open file. 102 unless (open STATE, $dnsmasq_state_file) { 103 warn "read_state: can't open $dnsmasq_state_file!\n"; 104 return 0; 105 } 106 # Mark all hosts as offline, saving old state. 107 foreach $ether (keys %{$list}) { 108 $list->{$ether}->{'old_online'} = $list->{$ether}->{'online'}; 109 $list->{$ether}->{'online'} = 0; 110 } 111 # Read hosts. 112 while (<STATE>) { 113 chomp; 114 @host{qw/raw_lease ether_addr ip_addr hostname raw_client_id/} = split /\s+/; 115 $ether = $host{ether_addr}; 116 # Mark each online host as online. 117 $list->{$ether}->{'online'} = 1; 118 # Copy data to master list. 119 foreach $key (keys %host) { 120 $list->{$ether}->{$key} = $host{$key}; 121 } 122 } 123 close STATE; 124 # Handle changes in offline/online state. (The sub &do_host() handles 125 # all of the extra stuff to do with a host's data once it is read. 126 foreach $ether (keys %{$list}) { 127 $old = $list->{$ether}->{'old_online'}; 128 $new = $list->{$ether}->{'online'}; 129 if (not $old) { 130 if (not $new) { 131 do_host($ether, 'offline'); 132 } else { 133 do_host($ether, 'join'); 134 } 135 } else { 136 if (not $new) { 137 do_host($ether, 'leave'); 138 } else { 139 do_host($ether, 'online'); 140 } 141 } 142 } 143 # Sort hosts by IP ;-) 144 @hosts = sort byip values %{$list}; 145 # Copy sorted list to template data store. 146 $data->{'hosts'} = [ @hosts ]; 147} 148 149# Do stuff per host. 150sub do_host { 151 my ($ether, $status) = @_; 152 153 # Find textual representation of DHCP client ID. 154 if ($list->{$ether}->{'raw_client_id'} eq '*') { 155 $list->{$ether}->{'text_client_id'} = 'None'; 156 } else { 157 my $text = ""; 158 foreach $char (split /:/, $list->{$ether}->{'raw_client_id'}) { 159 $char = pack('H2', $char); 160 if (ord($char) >= 32 and ord($char) <= 127) { 161 $text .= $char; 162 } else { 163 $text .= "?"; 164 } 165 } 166 $list->{$ether}->{'text_client_id'} = $text; 167 } 168 169 # Convert lease expiration date/time to text. 170 if ($list->{$ether}->{'raw_lease'} == 0) { 171 $list->{$ether}->{'text_lease'} = 'Never'; 172 } else { 173 $list->{$ether}->{'text_lease'} = nice_time($list->{$ether}->{'raw_lease'}); 174 } 175 176 if ($status eq 'offline') { 177 # Nothing to do. 178 } elsif ($status eq 'online') { 179 # Nothing to do. 180 } elsif ($status eq 'join') { 181 # Update times for joining host. 182 print "do_host: $ether joined the network.\n"; 183 $list->{$ether}->{'join_time'} = time; 184 $list->{$ether}->{'since'} = nice_time(time); 185 } elsif ($status eq 'leave') { 186 # Update times for leaving host. 187 print "do_host: $ether left the network.\n"; 188 $list->{$ether}->{'leave_time'} = time; 189 $list->{$ether}->{'since'} = nice_time(time); 190 } 191 192} 193 194# Convert time to a string representation. 195sub nice_time { 196 my $time = shift; 197 my ($sec, $min, $hour, $mday, $mon, $year, $wday, $yday, $dst) = localtime($time); 198 $sec = pad($sec, '0', 2); 199 $min = pad($min, '0', 2); 200 $hour = pad($hour, '0', 2); 201 $mon = pad($mon, '0', 2); 202 $mday = pad($mday, '0', 2); 203 return "$mon/$mday $hour:$min:$sec"; 204} 205 206# Pad string to a certain length by repeatedly prepending another string. 207sub pad { 208 my ($text, $pad, $length) = @_; 209 while (length($text) < $length) { 210 $text = "$pad$text"; 211 } 212 return $text; 213} 214 215# Compare two IP addresses. (Uses $a and $b from sort.) 216sub byip { 217 # Split into octets. 218 my @a = split /\./, $a->{ip_addr}; 219 my @b = split /\./, $b->{ip_addr}; 220 # Compare octets. 221 foreach $n (0..3) { 222 return $a[$n] <=> $b[$n] if ($a[$n] != $b[$n]); 223 } 224 # If we get here there is no difference. 225 return 0; 226} 227 228# Output HTML file. 229sub write_output { 230 # Create new template object. 231 my $template = Template->new( 232 { 233 ABSOLUTE => 1, # /var/www/... is an absolute path 234 OUTPUT => $html_output_file # put it here, not STDOUT 235 } 236 ); 237 $data->{'updated'} = nice_time(time); # add "(updated ...)" to file 238 unless ($template->process($html_template_file, $data)) { # do it 239 warn "write_output: Template Toolkit error: " . $template->error() . "\n"; 240 return 0; 241 } 242 print "write_output: page updated.\n"; 243 return 1; 244} 245 246sub show_license { 247 while (<DATA>) { 248 print; 249 $line++; 250 if ($line == 24) { <>; $line = 1; } 251 } 252} 253 254# Main loop. 255while (1) { 256 # Check for state change. 257 if (check_state()) { 258 read_state(); 259 sleep 1; # Sleep for a second just so we don't wear anything 260 # out. (By not sleeping the whole time after a change 261 # we can detect rapid changes more easily--like if 300 262 # hosts all come back online, they show up quicker.) 263 } else { 264 sleep $wait_time; # Take a nap. 265 } 266 write_output(); # Write the file anyway. 267} 268__DATA__ 269 GNU GENERAL PUBLIC LICENSE 270 Version 2, June 1991 271 272 Copyright (C) 1989, 1991 Free Software Foundation, Inc. 273 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 274 Everyone is permitted to copy and distribute verbatim copies 275 of this license document, but changing it is not allowed. 276 277 Preamble 278 279 The licenses for most software are designed to take away your 280freedom to share and change it. By contrast, the GNU General Public 281License is intended to guarantee your freedom to share and change free 282software--to make sure the software is free for all its users. This 283General Public License applies to most of the Free Software 284Foundation's software and to any other program whose authors commit to 285using it. (Some other Free Software Foundation software is covered by 286the GNU Library General Public License instead.) You can apply it to 287your programs, too. 288 289 When we speak of free software, we are referring to freedom, not 290price. Our General Public Licenses are designed to make sure that you 291have the freedom to distribute copies of free software (and charge for 292this service if you wish), that you receive source code or can get it 293if you want it, that you can change the software or use pieces of it 294in new free programs; and that you know you can do these things. 295 296 To protect your rights, we need to make restrictions that forbid 297anyone to deny you these rights or to ask you to surrender the rights. 298These restrictions translate to certain responsibilities for you if you 299distribute copies of the software, or if you modify it. 300 301 For example, if you distribute copies of such a program, whether 302gratis or for a fee, you must give the recipients all the rights that 303you have. You must make sure that they, too, receive or can get the 304source code. And you must show them these terms so they know their 305rights. 306 307 We protect your rights with two steps: (1) copyright the software, and 308(2) offer you this license which gives you legal permission to copy, 309distribute and/or modify the software. 310 311 Also, for each author's protection and ours, we want to make certain 312that everyone understands that there is no warranty for this free 313software. If the software is modified by someone else and passed on, we 314want its recipients to know that what they have is not the original, so 315that any problems introduced by others will not reflect on the original 316authors' reputations. 317 318 Finally, any free program is threatened constantly by software 319patents. We wish to avoid the danger that redistributors of a free 320program will individually obtain patent licenses, in effect making the 321program proprietary. To prevent this, we have made it clear that any 322patent must be licensed for everyone's free use or not licensed at all. 323 324 The precise terms and conditions for copying, distribution and 325modification follow. 326 327 GNU GENERAL PUBLIC LICENSE 328 TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION 329 330 0. This License applies to any program or other work which contains 331a notice placed by the copyright holder saying it may be distributed 332under the terms of this General Public License. The "Program", below, 333refers to any such program or work, and a "work based on the Program" 334means either the Program or any derivative work under copyright law: 335that is to say, a work containing the Program or a portion of it, 336either verbatim or with modifications and/or translated into another 337language. (Hereinafter, translation is included without limitation in 338the term "modification".) Each licensee is addressed as "you". 339 340Activities other than copying, distribution and modification are not 341covered by this License; they are outside its scope. The act of 342running the Program is not restricted, and the output from the Program 343is covered only if its contents constitute a work based on the 344Program (independent of having been made by running the Program). 345Whether that is true depends on what the Program does. 346 347 1. You may copy and distribute verbatim copies of the Program's 348source code as you receive it, in any medium, provided that you 349conspicuously and appropriately publish on each copy an appropriate 350copyright notice and disclaimer of warranty; keep intact all the 351notices that refer to this License and to the absence of any warranty; 352and give any other recipients of the Program a copy of this License 353along with the Program. 354 355You may charge a fee for the physical act of transferring a copy, and 356you may at your option offer warranty protection in exchange for a fee. 357 358 2. You may modify your copy or copies of the Program or any portion 359of it, thus forming a work based on the Program, and copy and 360distribute such modifications or work under the terms of Section 1 361above, provided that you also meet all of these conditions: 362 363 a) You must cause the modified files to carry prominent notices 364 stating that you changed the files and the date of any change. 365 366 b) You must cause any work that you distribute or publish, that in 367 whole or in part contains or is derived from the Program or any 368 part thereof, to be licensed as a whole at no charge to all third 369 parties under the terms of this License. 370 371 c) If the modified program normally reads commands interactively 372 when run, you must cause it, when started running for such 373 interactive use in the most ordinary way, to print or display an 374 announcement including an appropriate copyright notice and a 375 notice that there is no warranty (or else, saying that you provide 376 a warranty) and that users may redistribute the program under 377 these conditions, and telling the user how to view a copy of this 378 License. (Exception: if the Program itself is interactive but 379 does not normally print such an announcement, your work based on 380 the Program is not required to print an announcement.) 381 382These requirements apply to the modified work as a whole. If 383identifiable sections of that work are not derived from the Program, 384and can be reasonably considered independent and separate works in 385themselves, then this License, and its terms, do not apply to those 386sections when you distribute them as separate works. But when you 387distribute the same sections as part of a whole which is a work based 388on the Program, the distribution of the whole must be on the terms of 389this License, whose permissions for other licensees extend to the 390entire whole, and thus to each and every part regardless of who wrote it. 391 392Thus, it is not the intent of this section to claim rights or contest 393your rights to work written entirely by you; rather, the intent is to 394exercise the right to control the distribution of derivative or 395collective works based on the Program. 396 397In addition, mere aggregation of another work not based on the Program 398with the Program (or with a work based on the Program) on a volume of 399a storage or distribution medium does not bring the other work under 400the scope of this License. 401 402 3. You may copy and distribute the Program (or a work based on it, 403under Section 2) in object code or executable form under the terms of 404Sections 1 and 2 above provided that you also do one of the following: 405 406 a) Accompany it with the complete corresponding machine-readable 407 source code, which must be distributed under the terms of Sections 408 1 and 2 above on a medium customarily used for software interchange; or, 409 410 b) Accompany it with a written offer, valid for at least three 411 years, to give any third party, for a charge no more than your 412 cost of physically performing source distribution, a complete 413 machine-readable copy of the corresponding source code, to be 414 distributed under the terms of Sections 1 and 2 above on a medium 415 customarily used for software interchange; or, 416 417 c) Accompany it with the information you received as to the offer 418 to distribute corresponding source code. (This alternative is 419 allowed only for noncommercial distribution and only if you 420 received the program in object code or executable form with such 421 an offer, in accord with Subsection b above.) 422 423The source code for a work means the preferred form of the work for 424making modifications to it. For an executable work, complete source 425code means all the source code for all modules it contains, plus any 426associated interface definition files, plus the scripts used to 427control compilation and installation of the executable. However, as a 428special exception, the source code distributed need not include 429anything that is normally distributed (in either source or binary 430form) with the major components (compiler, kernel, and so on) of the 431operating system on which the executable runs, unless that component 432itself accompanies the executable. 433 434If distribution of executable or object code is made by offering 435access to copy from a designated place, then offering equivalent 436access to copy the source code from the same place counts as 437distribution of the source code, even though third parties are not 438compelled to copy the source along with the object code. 439 440 4. You may not copy, modify, sublicense, or distribute the Program 441except as expressly provided under this License. Any attempt 442otherwise to copy, modify, sublicense or distribute the Program is 443void, and will automatically terminate your rights under this License. 444However, parties who have received copies, or rights, from you under 445this License will not have their licenses terminated so long as such 446parties remain in full compliance. 447 448 5. You are not required to accept this License, since you have not 449signed it. However, nothing else grants you permission to modify or 450distribute the Program or its derivative works. These actions are 451prohibited by law if you do not accept this License. Therefore, by 452modifying or distributing the Program (or any work based on the 453Program), you indicate your acceptance of this License to do so, and 454all its terms and conditions for copying, distributing or modifying 455the Program or works based on it. 456 457 6. Each time you redistribute the Program (or any work based on the 458Program), the recipient automatically receives a license from the 459original licensor to copy, distribute or modify the Program subject to 460these terms and conditions. You may not impose any further 461restrictions on the recipients' exercise of the rights granted herein. 462You are not responsible for enforcing compliance by third parties to 463this License. 464 465 7. If, as a consequence of a court judgment or allegation of patent 466infringement or for any other reason (not limited to patent issues), 467conditions are imposed on you (whether by court order, agreement or 468otherwise) that contradict the conditions of this License, they do not 469excuse you from the conditions of this License. If you cannot 470distribute so as to satisfy simultaneously your obligations under this 471License and any other pertinent obligations, then as a consequence you 472may not distribute the Program at all. For example, if a patent 473license would not permit royalty-free redistribution of the Program by 474all those who receive copies directly or indirectly through you, then 475the only way you could satisfy both it and this License would be to 476refrain entirely from distribution of the Program. 477 478If any portion of this section is held invalid or unenforceable under 479any particular circumstance, the balance of the section is intended to 480apply and the section as a whole is intended to apply in other 481circumstances. 482 483It is not the purpose of this section to induce you to infringe any 484patents or other property right claims or to contest validity of any 485such claims; this section has the sole purpose of protecting the 486integrity of the free software distribution system, which is 487implemented by public license practices. Many people have made 488generous contributions to the wide range of software distributed 489through that system in reliance on consistent application of that 490system; it is up to the author/donor to decide if he or she is willing 491to distribute software through any other system and a licensee cannot 492impose that choice. 493 494This section is intended to make thoroughly clear what is believed to 495be a consequence of the rest of this License. 496 497 8. If the distribution and/or use of the Program is restricted in 498certain countries either by patents or by copyrighted interfaces, the 499original copyright holder who places the Program under this License 500may add an explicit geographical distribution limitation excluding 501those countries, so that distribution is permitted only in or among 502countries not thus excluded. In such case, this License incorporates 503the limitation as if written in the body of this License. 504 505 9. The Free Software Foundation may publish revised and/or new versions 506of the General Public License from time to time. Such new versions will 507be similar in spirit to the present version, but may differ in detail to 508address new problems or concerns. 509 510Each version is given a distinguishing version number. If the Program 511specifies a version number of this License which applies to it and "any 512later version", you have the option of following the terms and conditions 513either of that version or of any later version published by the Free 514Software Foundation. If the Program does not specify a version number of 515this License, you may choose any version ever published by the Free Software 516Foundation. 517 518 10. If you wish to incorporate parts of the Program into other free 519programs whose distribution conditions are different, write to the author 520to ask for permission. For software which is copyrighted by the Free 521Software Foundation, write to the Free Software Foundation; we sometimes 522make exceptions for this. Our decision will be guided by the two goals 523of preserving the free status of all derivatives of our free software and 524of promoting the sharing and reuse of software generally. 525 526 NO WARRANTY 527 528 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY 529FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN 530OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES 531PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED 532OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 533MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS 534TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE 535PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, 536REPAIR OR CORRECTION. 537 538 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 539WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR 540REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, 541INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING 542OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED 543TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY 544YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER 545PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE 546POSSIBILITY OF SUCH DAMAGES. 547 548 END OF TERMS AND CONDITIONS 549 550 How to Apply These Terms to Your New Programs 551 552 If you develop a new program, and you want it to be of the greatest 553possible use to the public, the best way to achieve this is to make it 554free software which everyone can redistribute and change under these terms. 555 556 To do so, attach the following notices to the program. It is safest 557to attach them to the start of each source file to most effectively 558convey the exclusion of warranty; and each file should have at least 559the "copyright" line and a pointer to where the full notice is found. 560 561 <one line to give the program's name and a brief idea of what it does.> 562 Copyright (C) <year> <name of author> 563 564 This program is free software; you can redistribute it and/or modify 565 it under the terms of the GNU General Public License as published by 566 the Free Software Foundation; either version 2 of the License, or 567 (at your option) any later version. 568 569 This program is distributed in the hope that it will be useful, 570 but WITHOUT ANY WARRANTY; without even the implied warranty of 571 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 572 GNU General Public License for more details. 573 574 You should have received a copy of the GNU General Public License 575 along with this program; if not, write to the Free Software 576 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 577 578 579Also add information on how to contact you by electronic and paper mail. 580 581If the program is interactive, make it output a short notice like this 582when it starts in an interactive mode: 583 584 Gnomovision version 69, Copyright (C) year name of author 585 Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 586 This is free software, and you are welcome to redistribute it 587 under certain conditions; type `show c' for details. 588 589The hypothetical commands `show w' and `show c' should show the appropriate 590parts of the General Public License. Of course, the commands you use may 591be called something other than `show w' and `show c'; they could even be 592mouse-clicks or menu items--whatever suits your program. 593 594You should also get your employer (if you work as a programmer) or your 595school, if any, to sign a "copyright disclaimer" for the program, if 596necessary. Here is a sample; alter the names: 597 598 Yoyodyne, Inc., hereby disclaims all copyright interest in the program 599 `Gnomovision' (which makes passes at compilers) written by James Hacker. 600 601 <signature of Ty Coon>, 1 April 1989 602 Ty Coon, President of Vice 603 604This General Public License does not permit incorporating your program into 605proprietary programs. If your program is a subroutine library, you may 606consider it more useful to permit linking proprietary applications with the 607library. If this is what you want to do, use the GNU Library General 608Public License instead of this License. 609