diff --git a/gen_tlsa.pl b/gen_tlsa.pl
index 1d05000..d3781d4 100755
--- a/gen_tlsa.pl
+++ b/gen_tlsa.pl
@@ -18,24 +18,29 @@ sub usage {
 
 usage() if (scalar(@ARGV) != 2);
 
-my $state = WAIT_BEGIN;
-my $pem = '';
+gen_tlsa(@ARGV);
 
-open(my $fh, '<', $ARGV[1]);
-while(my $line = <$fh>) {
-    if ($state == WAIT_BEGIN) {
-	if ($line=~/^-----BEGIN CERTIFICATE-----/) {
-	    $state = WAIT_END;
-	}
-    } elsif ($state == WAIT_END) {
-	if ($line=~/^-----END CERTIFICATE-----/) {
-	    last;
-	} else {
-	    $pem.=$line;
+sub gen_tlsa {
+    my ($label, $cert_file) = @_;
+    my $state = WAIT_BEGIN;
+    my $pem = '';
+    my ($fh, $line);
+    
+    open($fh, '<', $cert_file);
+    while($line = <$fh>) {
+	if ($state == WAIT_BEGIN) {
+	    if ($line=~/^-----BEGIN CERTIFICATE-----/) {
+		$state = WAIT_END;
+	    }
+	} elsif ($state == WAIT_END) {
+	    if ($line=~/^-----END CERTIFICATE-----/) {
+		last;
+	    } else {
+		$pem.=$line;
+	    }
 	}
     }
+    close($fh);
+    say($label, ' IN TLSA 1 0 1 ',
+	Digest::SHA::sha256_hex(decode_base64($pem)));
 }
-close($fh);
-say $ARGV[0], ' IN TLSA 1 0 1 ', Digest::SHA::sha256_hex(decode_base64($pem));
-
-#say $pem;