Force the root label to have 0 labels

TODO.markdown

@@ -13,12 +13,6 @@ things that need to be fixed.
    -edns NSID is another
 * Add tsig check in 'q'?
 
-## BUGS
-
-* ListenAndServe has trouble with v6:
-    Failed to setup the udp6 server: listen udp6 <nil>:8053: address already in use
-    Failed to setup the tcp6 server: listen tcp6 <nil>:8053: address already in use
-
 ## Examples to add
 
 * Nameserver, with a small zone, 1 KSK and online signing;

label_test.go

@@ -27,8 +27,8 @@ func TestCompareLabels(t *testing.T) {
 		t.Logf("%s with %s should be %d", s1, s5, 1)
 		t.Fail()
 	}
-	if CompareLabels(".", ".") != 1 {
-		t.Logf("%s with %s should be %d", ".", ".", 1)
+	if CompareLabels(".", ".") != 0 {
+		t.Logf("%s with %s should be %d", ".", ".", 0)
 		t.Fail()
 	}
 }
@@ -55,9 +55,8 @@ func TestSplitLabels(t *testing.T) {
 		t.Logf("Labels should be 3, %s\n", s4)
 		t.Fail()
 	}
-        // Should this be 1 or 0...
-	if len(SplitLabels(".")) != 1 {
-		t.Logf("Labels should be 1, %s\n", ".")
+	if len(SplitLabels(".")) != 0 {
+		t.Logf("Labels should be 0, %s\n", ".")
 		t.Fail()
 	}
 }

labels.go

@@ -4,8 +4,12 @@ package dns
 
 // SplitLabels splits a domainname string into its labels.
 // www.miek.nl. returns []string{"www", "miek", "nl"}
-// . returns []string{"."}
+// The root label (.) returns nil
 func SplitLabels(s string) []string {
+        if (s == ".") {
+                return nil
+        }
+
 	k := 0
 	labels := make([]string, 0)
 	last := byte('.')
@@ -34,9 +38,6 @@ func SplitLabels(s string) []string {
 //
 // www.miek.nl. and miek.nl. have two labels in common: miek and nl
 // www.miek.nl. and www.bla.nl. have one label in common: nl
-// Be aware of these corner cases:
-// . and . have one label in common
-// . and "" (empty) have one label in common
 func CompareLabels(s1, s2 string) (n int) {
 	l1 := SplitLabels(s1)
 	l2 := SplitLabels(s2)