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|
#!/usr/bin/perl
# The new, improced "debug hostname" which makes it easy to make an
# offline test suite based on real-world DNS records
# This is the MaraDNS 0.9.17 version og debug.hostname
# Some global variables
$ASKMARA = "/usr/bin/askmara";
$TIMEOUT = "3";
$hostname = shift || "Awww.example.com.";
$ROOT_SERVER = shift || "198.41.0.4";
# Try to get the IP for a singlr host name; this has to be a
# function because of the way DNS is set up...we may need to
# recurse
# Input: Name to resolve; server to bug; bailiwick; recursion depth
# Ouput: the IPs in ddip format
sub resolve_name {
my($name,$server,$bailiwick,$depth,@visited) = @_;
my($level) = 1;
my(@name_servers,@name_server_ips,@name_server_ips_new);
my($answer) = ("");
my(%seen,$item);
foreach $item (@visited) {
$seen{$item} = 1;
}
if($depth > 0) {print "# Entering recursion level $depth\n"}
if($depth > 20) {
return "255.255.255.255";
}
# Convert name in to an askmara-compatible format
if($name !~ /^A/) {
$name = "A" . $name;
}
if($name !~ /\.$/) {
$name = $name . ".";
}
# Make the name lower case
$name =~ tr/A-Z/a-z/;
$name =~ s/^a/A/;
print "# The canonical name is $name\n";
# Add this name to the list of name servers we shall not attempt to
# resolve again (stops loops)
if($seen{$name}) {
print "# Already visited $name, exiting\n";
return "255.255.255.255";
}
@visited = ($name,@visited);
print "# Processing query for $name\n";
# Convert server in to name_server_ip format
@name_server_ips = ($server);
@name_servers = ("Aroot-server.invalid.");
# OK, get the name
while($level < 20) {
my($line);
# Run askmara
foreach $server (@name_server_ips) {
start_askmara:
if(!$server) {
goto nextserver;
}
#print "$ASKMARA -n -t $TIMEOUT $name $server \n";
open(ASKMARA,"$ASKMARA -n -t $TIMEOUT $name $server |") ||
die "Can not run $ASKMARA: $!\n";
# Process the output of askmara
@name_servers = ();
@name_servers_ips_new = ();
# See if we get a timeout or other hard error
$line = (<ASKMARA>); print $line;
if($line !~ /^# Querying/) {
close(ASKMARA);
return "255.255.255.255";
}
$line = (<ASKMARA>); print $line;
if($line =~ /^# Hard Error/) {
close(ASKMARA);
goto nextserver;
}
print "# Name: $name\n";
if($line !~ /^\# Question\: $name/) {
close(ASKMARA);
goto start_askmara;
}
$line = (<ASKMARA>); print $line;
# Authoritative answers
my($answer) = "";
while($line =~ /^[A-Z@]/) {
chop($line);
my(@fields) = split(/\|/,$line);
# A answers
if($line =~ /^A/) {
if($fields[2] eq "255.255.255.255") {
goto nextline;
}
if($answer) {
$answer .= ";" . $fields[2];
}
else {
$answer = $fields[2];
}
}
# CNAME answers
elsif($line =~ /^C/) {
my($query) = "A" . $fields[2];
# Recursion time
if(!$seen{$query}) {
my($reply) = (resolve_name($query,$ROOT_SERVER,".",
$depth + 1),@visited);
}
if($reply ne "255.255.255.255") {
if($answer) {
$answer .= ";" . $reply;
}
else {
$answer = $reply;
}
}
}
nextline:
$line = (<ASKMARA>); print $line;
}
if($answer) {
if($depth > 0) {print "# Exiting recursion level $depth\n"}
return $answer;
}
# Referrals
# Ignore everything until we hit the referral section
while($line !~ /^# NS replies:/) {
$line = (<ASKMARA>); print $line;
if(eof(ASKMARA)) {
print("# A SECTION ASKMARA EOF\n");
return "255.255.255.255";
}
}
$line = (<ASKMARA>); print $line;
# Handle the NS replies
while($line =~ s/^\#?N//) {
chop($line);
my(@fields) = split(/\|/,$line);
# Make sure we are in bailiwick
if($fields[1] !~ /$bailiwick$/i) {
print "# Out-of-bailiwick; going to next server\n";
goto nextserver; # Sometimes, you gotta
}
@name_servers = (@name_servers,$fields[2]);
$line = (<ASKMARA>); print $line;
}
# Host not here is always an error
if($line =~ /^#S/) {
return "255.255.255.255";
}
# Handle the AR records
if($line !~ /^# AR replies:/) {
goto nextserver;
}
print "# Next-level name servers for $name: @name_servers\n";
@name_server_ips_new = ();
# And the AR replies
while(<ASKMARA>) {
$line = $_;
print $line;
chop($line);
if($line =~ s/^\#?A//) {
my(@fields) = split(/\|/,$line);
my($counter);
for($counter = 0; $counter <= $#name_servers;
$counter++) {
if($name_servers[$counter] eq $fields[0]) {
unshift(@name_server_ips_new,$fields[2]);
splice(@name_servers,$counter,1);
}
}
}
}
# The only elements in @name_servers at this point
# is the glueless stuff
my($ns);
foreach $ns (@name_servers) {
my($reply);
if(!$seen{$ns}) {
$reply = resolve_name($ns,$ROOT_SERVER,".",$depth + 1,
@visited);
}
if($reply ne "255.255.255.255") {
unshift(@name_server_ips_new,$reply);
}
}
print "# Next-level name server IPs for $name: @name_server_ips_new\n";
goto lastserver;
nextserver:
}
lastserver:
@name_server_ips = @name_server_ips_new;
@name_servers = ();
$level++;
print "# Level $level\n";
}
}
resolve_name($hostname,$ROOT_SERVER,".",0);
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