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Extend check_dns.pl so it can take a list of domains #338

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Extend check_dns.pl so it can take a list of domains #338

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205 changes: 108 additions & 97 deletions check_dns.pl
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Original file line number Diff line number Diff line change
Expand Up @@ -47,17 +47,18 @@ BEGIN
my $default_type = "A";
my $type = $default_type;
my $record;
my @records;
my $server;
my @servers;
my $expected_result;
my $expected_regex;
my $expected_regex2;
my $valid_expected_regex;
my $no_uniq_results;
my $randomize_servers;

%options = (
"s|server=s" => [ \$server, "DNS server(s) to query, can be a comma separated list of servers" ],
"r|record=s" => [ \$record, "DNS record to query" ],
"r|record=s" => [ \$record, "DNS record(s) to query, can be a comma separated list of records" ],
"q|type=s" => [ \$type, "DNS query type (defaults to '$default_type' record)" ],
"e|expected-result=s" => [ \$expected_result, "Expected results, comma separated" ],
"R|expected-regex=s" => [ \$expected_regex, "Expected regex to validate against each returned result (anchored, so if testing partial TXT records you may need to use .* before and after the regex, and if differing TXT records are returned then use alternation '|' to support the different regex, see tests/test_dns.sh for an example)" ],
Expand All @@ -73,16 +74,23 @@ BEGIN
for(my $i=0; $i < scalar @servers; $i++){
$servers[$i] = validate_host($servers[$i]);
}

grep($type, @valid_types) or usage "unsupported type '$type' given, must be one of: " . join(",", @valid_types);
if($type eq "PTR"){
$record = isIP($record) or usage "invalid record given for type PTR, should be an IP";
} elsif($type eq "SRV"){
$record =~ /^[A-Za-z_\.-]+\.$domain_regex/ or usage "invalid record given for type SRV, must contain only alphanumeric, underscores, dashes followed by a valid domain name format";
} else {
$record = isDomain($record) or isFqdn($record) or usage "invalid record given, should be a domain or fully qualified host name";

$record or usage "record(s) not specified";
@records = split(/\s*[,\s]\s*/, $record);
for(my $i=0; $i < scalar @records; $i++){
if($type eq "PTR"){
$records[$i] = isIP($records[$i]) or usage "invalid record " . $records[$i] . " given for type PTR, should be an IP";
} elsif($type eq "SRV"){
$records[$i] =~ /^[A-Za-z_\.-]+\.$domain_regex/ or usage "invalid record" . $records[$i] . " given for type SRV, must contain only alphanumeric, underscores, dashes followed by a valid domain name format";
} else {
$records[$i] = isDomain($records[$i]) or isFqdn($records[$i]) or usage "invalid record " . $records[$i] . " given, should be a domain or fully qualified host name";
}
}

vlog_option "server", join(",", @servers);
vlog_option "record", $record;
vlog_option "record", join(",", @records);
vlog_option "type", $type;
if($randomize_servers){
vlog2 "randomizing nameserver list";
Expand All @@ -104,7 +112,7 @@ BEGIN
}
vlog_option "expected results", $expected_result;
}
$expected_regex2 = validate_regex($expected_regex) if defined($expected_regex);
$valid_expected_regex = validate_regex($expected_regex) if defined($expected_regex);

vlog2;
set_timeout();
Expand All @@ -128,101 +136,104 @@ BEGIN
$res->udp_timeout(2);
vlog2 "set resolver timeout to 2 secs per server";

my @results;
my @rogue_results;
my @missing_results;

vlog2 "sending query for $record $type record";
my $start = time;
my $query = $res->query($record, $type);
my $stop = time;
my $total_time = sprintf("%.4f", $stop - $start);
vlog2;
plural @servers;
$query or quit "CRITICAL", "query returned with no answer from server$plural " . join(",", @servers) . " in $total_time secs" . ( $verbose ? " for record '$record' type '$type'" : "");
vlog2 "query returned in $total_time secs";
my $perfdata = " | dns_query_time='${total_time}s'";

vlog3 "returned records:\n";
foreach my $rr ($query->answer){
vlog3 Dumper($rr);
my $result;
if($rr->type eq "A"){
$result = $rr->address;
} elsif($rr->type eq "CNAME"){
$result = $rr->cname;
$result =~ s/\.$//;
} elsif($rr->type eq "MX"){
$result = $rr->exchange;
} elsif($rr->type eq "NS"){
$result = $rr->nsdname;
} elsif($rr->type eq "PTR"){
$result = $rr->ptrdname;
} elsif($rr->type eq "SOA"){
$result = $rr->serial;
} elsif($rr->type eq "SRV"){
$result = $rr->target;
} elsif($rr->type eq "TXT"){
$result = $rr->txtdata;
} else {
quit "UNKNOWN", "unknown/unsupported record type '$rr->type' returned for record '$record'";
}
vlog2 "got result: $result\n";
if($type eq "A"){
isIP($result) or quit "CRITICAL", "invalid result '$result' returned for A record by DNS server, expected IP address for A record$perfdata";
} elsif(grep { $type eq $_ } qw/CNAME MX NS PTR SRV/){
isFqdn($result) or quit "CRITICAL", "invalid result '$result' returned " . ($verbose ? "for record '$record' type '$type' ": "") . "by DNS server, expected FQDN for this record type$perfdata";
} elsif($type eq "SOA"){
isInt($result) or quit "CRITICAL", "invalid serial result '$result' returned for SOA record " . ($verbose ? "'$record' ": "") . "by DNS server, expected an unsigned integer$perfdata";
}
push(@results, $result);
if(@expected_results){
unless(grep(lc $_ eq lc $result, @expected_results)){
vlog3 "result '$result' wasn't found in expected results, added to rogue list";
push(@rogue_results, $result);
my $start_calls = time;
for(my $i=0; $i < scalar @records; $i++){
vlog2 "sending query for $records[$i] $type record";
my @results;
my @rogue_results;
my @missing_results;
my $start_call = time;
my $query = $res->query($records[$i], $type);
my $stop_call = time;
my $call_time = sprintf("%.4f", $stop_call - $start_call);
vlog2;
plural @servers;
$query or quit "CRITICAL", "query returned with no answer from server$plural " . join(",", @servers) . " in $call_time secs" . ( $verbose ? " for record '$records[$i]' type '$type'" : "");
vlog2 "query returned in $call_time secs";
my $perfdata = " | dns_query_time='${call_time}s'";

vlog3 "returned records:\n";
foreach my $rr ($query->answer){
vlog3 Dumper($rr);
my $result;
if($rr->type eq "A"){
$result = $rr->address;
} elsif($rr->type eq "CNAME"){
$result = $rr->cname;
$result =~ s/\.$//;
} elsif($rr->type eq "MX"){
$result = $rr->exchange;
} elsif($rr->type eq "NS"){
$result = $rr->nsdname;
} elsif($rr->type eq "PTR"){
$result = $rr->ptrdname;
} elsif($rr->type eq "SOA"){
$result = $rr->serial;
} elsif($rr->type eq "SRV"){
$result = $rr->target;
} elsif($rr->type eq "TXT"){
$result = $rr->txtdata;
} else {
quit "UNKNOWN", "unknown/unsupported record type '$rr->type' returned for record '$records[$i]'";
}
vlog2 "got result: $result\n";
if($type eq "A"){
isIP($result) or quit "CRITICAL", "invalid result '$result' returned for A record by DNS server, expected IP address for A record$perfdata";
} elsif(grep { $type eq $_ } qw/CNAME MX NS PTR SRV/){
isFqdn($result) or quit "CRITICAL", "invalid result '$result' returned " . ($verbose ? "for record '$record' type '$type' ": "") . "by DNS server, expected FQDN for this record type$perfdata";
} elsif($type eq "SOA"){
isInt($result) or quit "CRITICAL", "invalid serial result '$result' returned for SOA record " . ($verbose ? "'$records[$i]' ": "") . "by DNS server, expected an unsigned integer$perfdata";
}
push(@results, $result);
if(@expected_results){
unless(grep(lc $_ eq lc $result, @expected_results)){
vlog3 "result '$result' wasn't found in expected results, added to rogue list";
push(@rogue_results, $result);
}
}
}
}

@results or quit "CRITICAL", "no result received for '$record' $type record from servers " . join(",", @servers) . " in $total_time secs";
@results or quit "CRITICAL", "no result received for '$records[$i]' $type record from servers " . join(",", @servers) . " in $call_time secs";
my @results_uniq = sort(uniq_array(@results));

my @results_uniq = sort(uniq_array(@results));

foreach my $expected_result2 (@expected_results){
unless(grep(lc $_ eq lc $expected_result2, @results_uniq)){
vlog3 "$expected_result2 wasn't found in results, adding to missing list";
push(@missing_results, $expected_result2);
foreach my $exp_result (@expected_results){
unless(grep(lc $_ eq lc $exp_result, @results_uniq)){
vlog3 "$exp_result wasn't found in results, adding to missing list";
push(@missing_results, $exp_result);
}
}
}

my @regex_mismatches;
if($expected_regex2){
foreach my $result (@results){
$result =~ /^$expected_regex2$/ or push(@regex_mismatches, $result);
my @regex_mismatches;
if($valid_expected_regex){
foreach my $result (@results){
$result =~ /^$valid_expected_regex$/ or push(@regex_mismatches, $result);
}
}
@regex_mismatches = sort(uniq_array(@regex_mismatches)) if(@regex_mismatches);
$msg .= "\n$records[$i] $type record ";
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multi-line will break some monitoring servers output / dashboards as traditionally only 1 line is guaranteed to be displayed, you wouldn't want the output on some systems to be "DNS OK:" and nothing else...

if(scalar @rogue_results or scalar @missing_results){
critical;
$msg .= "MISMATCH, expected '" . join(",", @expected_results) . "', got '";
} elsif(scalar @regex_mismatches){
critical;
$msg .= "regex validation FAILED on '" . join("','", @regex_mismatches) . "' against regex '$expected_regex', returns '";
} elsif($type eq "SOA"){
$msg .= "OK return serial '";
} else {
$msg .= "OK return '";
}
if ($no_uniq_results){
$msg .= join("','", @results);
} else {
$msg .= join("','", @results_uniq);
}
$msg .= "'";
$msg .= " | dns_query_time='${call_time}s'" if $verbose;
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this will mess up in --verbose mode

}
@regex_mismatches = sort(uniq_array(@regex_mismatches)) if(@regex_mismatches);

$msg .= "$record $type record ";

if(scalar @rogue_results or scalar @missing_results){
critical;
$msg .= "mismatch, expected '" . join(",", @expected_results) . "', got '";
} elsif(scalar @regex_mismatches){
critical;
$msg .= "regex validation failed on '" . join("','", @regex_mismatches) . "' against regex '$expected_regex', returns '";
} elsif($type eq "SOA"){
$msg .= "return serial '";
} else {
$msg .= "returns '";
}
if($no_uniq_results){
$msg .= join("','", @results);
} else {
$msg .= join("','", @results_uniq);
}
$msg .= "'";
$msg .= " in $total_time secs" if $verbose;

my $stop_calls = time;
my $total_time = sprintf("%.4f", $stop_calls - $start_calls);
my $perfdata = "\n | total_dns_query_time='${total_time}s'";
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multi-line will break some monitoring servers output

$msg .= $perfdata;

my $extended_command = dirname $progname;
Expand Down