reverse zone: fix Normalize (#4621)

Make normalize return multiple "hosts" (= reverse zones) when a
non-octet boundary cidr is given.

Added pkg/cidr package that holds the cidr calculation routines; felt
they didn't really fit dnsutil.

This change means the IPNet return parameter isn't needed, the hosts are
all correct. The tests that tests this is also removed: TestSplitHostPortReverse
The fallout was that zoneAddr _also_ doesn't need the IPNet member, that
in turn make it visible that zoneAddr in address.go duplicated a bunch
of stuff from register.go; removed/refactored that too.

Created a plugin.OriginsFromArgsOrServerBlock to help plugins do the
right things, by consuming ZONE arguments; this now expands reverse
zones correctly. This is mostly mechanical.

Remove the reverse test in plugin/kubernetes which is a copy-paste from
a core test (which has since been fixed).

Remove MustNormalize as it has no plugin users.

This change is not backwards compatible to plugins that have a ZONE
argument that they parse in the setup util.

All in-tree plugins have been updated.

Signed-off-by: Miek Gieben <miek@miek.nl>

1 files changed, 4 insertions, 3 deletions

diff --git a/plugin/pkg/fall/fall.go b/plugin/pkg/fall/fall.go
index 6d0463fd2..dd42f8e04 100644
--- a/plugin/pkg/fall/fall.go
+++ b/plugin/pkg/fall/fall.go
@@ -31,10 +31,11 @@ func (f F) Through(qname string) bool {
 
 // setZones will set zones in f.
 func (f *F) setZones(zones []string) {
+	z := []string{}
 	for i := range zones {
-		zones[i] = plugin.Host(zones[i]).Normalize()
+		z = append(z, plugin.Host(zones[i]).Normalize()...)
 	}
-	f.Zones = zones
+	f.Zones = z
 }
 
 // SetZonesFromArgs sets zones in f to the passed value or to "." if the slice is empty.
@@ -47,7 +48,7 @@ func (f *F) SetZonesFromArgs(zones []string) {
 }
 
 // Equal returns true if f and g are equal.
-func (f F) Equal(g F) bool {
+func (f *F) Equal(g F) bool {
 	if len(f.Zones) != len(g.Zones) {
 		return false
 	}