#!/usr/local/bin/perl -T # loc2earth.cgi - generates a redirect to Earth Viewer based on LOC record # [ see or RFC 1876 ] # by Christopher Davis # $Id: loc2earth.fcgi 01-jun-2005.19:13:03 afontana Exp $ die "I want 5.004 and I want it now" if $] < 5.004; # if you don't have FastCGI support, comment out this line and the two lines # later in the script with "NO FCGI" comments use CGI::Fast qw(:standard); # and uncomment the following instead. #use CGI qw(:standard); use Net::DNS '0.08'; # LOC support in 0.08 and later $res = new Net::DNS::Resolver; @samplehosts= ('www.kei.com', 'www.ndg.com.au', 'gw.alink.net', 'quasar.inexo.com.br', 'hubert.fukt.hk-r.se', 'sargent.cms.dmu.ac.uk', 'thales.mathematik.uni-ulm.de'); while (new CGI::Fast) { # NO FCGI -- comment out this line print header(-Title => "RFC 1876 Resources: Earth Viewer Demo"); # reinitialize these since FastCGI would keep them around otherwise @addrs = @netnames = (); $foundloc = 0; print ' RFC 1876 Resources: Earth Viewer Demo

RFC 1876 Resources

loc2earth: The Earth Viewer Demo

'; print p("This is a quick & dirty demonstration of the use of the", a({-href => 'http://www.dimensional.com/~mfuhr/perldns/'}, 'Net::DNS module'),"and the", a({-href => 'http://www-genome.wi.mit.edu/ftp/pub/software/WWW/cgi_docs.html'}, 'CGI.pm library'), "to write LOC-aware Web applications."); print startform("GET"); print p(strong("Hostname"),textfield(-name => host, -size => 50)); print p(submit, reset), endform; if (param('host')) { ($host = param('host')) =~ s/\s//g; # strip out spaces # check for numeric IPs and do reverse lookup to get name if ($host =~ m/^\d+\.\d+\.\d+\.\d+$/) { $query = $res->query($host); if (defined ($query)) { foreach $ans ($query->answer) { if ($ans->type eq "PTR") { $host = $ans->ptrdname; } } } } $query = $res->query($host,"LOC"); if (defined ($query)) { # then we got an answer of some sort foreach $ans ($query->answer) { if ($ans->type eq "LOC") { &print_loc($ans->rdatastr); $foundloc++; } elsif ($ans->type eq "CNAME") { # XXX should follow CNAME chains here } } } if (!$foundloc) { # try the RFC 1101 search bit $query = $res->query($host,"A"); if (defined ($query)) { foreach $ans ($query->answer) { if ($ans->type eq "A") { push(@addrs,$ans->address); } } } if (@addrs) { checkaddrs: foreach $ipstr (@addrs) { $ipnum = unpack("N",pack("CCCC",split(/\./,$ipstr,4))); ($ip1) = split(/\./,$ipstr); if ($ip1 >= 224) { # class D/E, treat as host addr $mask = 0xFFFFFFFF; } elsif ($ip1 >= 192) { # "class C" $mask = 0xFFFFFF00; } elsif ($ip1 >= 128) { # "class B" $mask = 0xFFFF0000; } else { # class A $mask = 0xFF000000; } $oldmask = 0; while ($oldmask != $mask) { $oldmask = $mask; $querystr = join(".", reverse (unpack("CCCC",pack("N",$ipnum & $mask)))) . ".in-addr.arpa"; $query = $res->query($querystr,"PTR"); if (defined ($query)) { foreach $ans ($query->answer) { if ($ans->type eq "PTR") { # we want the list in LIFO order unshift(@netnames,$ans->ptrdname); } } $query = $res->query($querystr,"A"); if (defined ($query)) { foreach $ans ($query->answer) { if ($ans->type eq "A") { $mask = unpack("L",pack("CCCC", split(/\./,$ans->address,4))); } } } } } if (@netnames) { foreach $network (@netnames) { $query = $res->query($network,"LOC"); if (defined ($query)) { foreach $ans ($query->answer) { if ($ans->type eq "LOC") { &print_loc($ans->rdatastr); $foundloc++; last checkaddrs; } elsif ($ans->type eq "CNAME") { # XXX should follow CNAME chains here } } } } } } } } if (!$foundloc) { print hr,p("Sorry, there appear to be no LOC records for the", "host $host in the DNS."); } } print hr,p("Some hosts with LOC records you may want to try:"), "

",join("\n
",@samplehosts),"

"; print '

Christopher Davis <ckd@kei.com>

'; } # NO FCGI -- comment out this line sub print_loc { local($rdata) = @_; ($latdeg,$latmin,$latsec,$lathem, $londeg,$lonmin,$lonsec,$lonhem) = split (/ /,$rdata); print hr,p("The host $host appears to be at", "${latdeg}°${latmin}'${latsec}\" ${lathem}", "latitude and ${londeg}°${lonmin}'${lonsec}\"", "${lonhem} longitude according to the DNS."); $evurl = ("http://www.fourmilab.ch/cgi-bin/uncgi/Earth?" . "lat=${latdeg}d${latmin}m${latsec}s&ns=" . (($lathem eq "S")?"lSouth":"lNorth") . "&lon=${londeg}d${lonmin}m${lonsec}s&ew=" . (($lonhem eq "W")?"West":"East") . "&alt="); print "

Generate an Earth Viewer image from "; foreach $alt (49, 204, 958, 35875) { print ('', $alt,'km '); } print " above this point

"; }