zones: introduce RingAddressEncoder and RingZero/RingOne implementations

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/zones/rings.go

@@ -7,6 +7,36 @@ const (
 	MaxZoneID = 0xf
 	// MaxNodeID indicates the highest Machine ID allowed within a Zone
 	MaxNodeID = 0xff - 1
+	// RingsCount indicates how many wireguard rings we have
+	RingsCount = 2
+)
+
+// RingAddressEncoder provides encoder/decoder access for a particular
+// Wireguard ring
+type RingAddressEncoder struct {
+	ID     int
+	Encode func(zoneID, nodeID int) (netip.Addr, bool)
+	Decode func(addr netip.Addr) (zoneID, nodeID int, ok bool)
+}
+
+var (
+	// RingZero is a wg0 address encoder/decoder
+	RingZero = RingAddressEncoder{
+		ID:     0,
+		Decode: ParseRingZeroAddress,
+		Encode: RingZeroAddress,
+	}
+	// RingOne is a wg1 address encoder/decoder
+	RingOne = RingAddressEncoder{
+		ID:     1,
+		Decode: ParseRingOneAddress,
+		Encode: RingOneAddress,
+	}
+	// Rings provides indexed access to the ring address encoders
+	Rings = [RingsCount]RingAddressEncoder{
+		RingZero,
+		RingOne,
+	}
 )
 
 // ValidZoneID checks if the given zoneID is a valid 4 bit zone number.