rings: DecodeRingZeroAddress() and DecodeRingOneAddress()

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

pkg/rings/decode.go

@@ -0,0 +1,62 @@
+package rings
+
+import (
+	"net/netip"
+
+	"darvaza.org/core"
+)
+
+// DecodeAddress ... TODO
+//
+// revive:disable:function-result-limit
+func DecodeAddress(addr netip.Addr) (Ring, RegionID, ZoneID, uint) {
+	// revive:enable:function-result-limit
+	if addr.IsValid() {
+		if addr.Is4In6() {
+			addr = addr.Unmap()
+		}
+
+		if addr.Is4() {
+			a4 := addr.As4()
+			return unsafeDecodeAddress(a4[0], a4[1], a4[2], a4[3])
+		}
+	}
+
+	return InvalidRing, 0, 0, 0
+}
+
+// revive:disable:function-result-limit
+func unsafeDecodeAddress(a, b, c, d byte) (Ring, RegionID, ZoneID, uint) {
+	// revive:enable:function-result-limit
+	switch {
+	case a != 10:
+		return InvalidRing, 0, 0, 0
+	case b&0xf0 != 0:
+		k := RingThree
+		r := RegionID(b >> 4)
+
+		n2 := uint(b & 0x0f)
+		n1 := uint(c)
+		n0 := uint(d)
+		n := n0 + n1<<8 + n2<<16
+
+		return k, r, 0, n
+	case b&0x0f != 0:
+		r := RegionID(b)
+		z := ZoneID(c >> 4)
+		k := core.IIf(z == 0, RingTwo, RingOne)
+
+		n1 := uint(c & 0x0f)
+		n0 := uint(d)
+		n := n0 + n1<<8
+
+		return k, r, z, n
+	default: // b == 0
+		k := RingZero
+		r := RegionID(c >> 4)
+		z := ZoneID(c & 0xf)
+		n := uint(d)
+
+		return k, r, z, n
+	}
+}

pkg/rings/rings.go

@@ -3,12 +3,27 @@
 package rings
 
 import (
+	"net/netip"
 	"syscall"
 
 	"darvaza.org/core"
 )
 
+// Ring ... TODO
+type Ring int
+
 const (
+	// InvalidRing ... TODO
+	InvalidRing Ring = iota - 1
+	// RingZero ... TODO
+	RingZero
+	// RingOne ... TODO
+	RingOne
+	// RingTwo ... TODO
+	RingTwo
+	// RingThree ... TODO
+	RingThree
+
 	// RegionMax indicates the highest number that can be used for a [RegionID].
 	RegionMax = (1 << 4) - 1
 	// ZoneMax indicates the highest number that can be used for a [ZoneID].
@@ -18,6 +33,17 @@ const (
 	// NodeZeroMax indicates the highest number that can be used for a [NodeID]
 	// when its a gateway connected to Ring 0 (backbone).
 	NodeZeroMax = (1 << 8) - 1
+
+	// RingZeroBits indicates the size of the prefix on the ring 0 (backbone) network.
+	RingZeroBits = 16
+	// RingOneBits indicates the size of the prefix on the ring 1 (lan) network.
+	RingOneBits = 20
+	// RingTwoBits indicates the size of the prefix on the ring 2 (services) network
+	// of all kubernetes clusters.
+	RingTwoBits = 20
+	// RingThreeBits indicates the size of the prefix on the ring 3 (pods) network
+	// of the kubernetes cluster of a region.
+	RingThreeBits = 12
 )
 
 // RegionID is the identifier of a region, valid between 1 and [RegionMax].
@@ -47,3 +73,174 @@ func (n NodeID) ValidZero() bool { return n > 0 && n <= NodeZeroMax }
 func ErrOutOfRange[T ~int | ~uint32](value T, field string) error {
 	return core.Wrap(syscall.EINVAL, "%s out of range (%v)", field, value)
 }
+
+// RingZeroPrefix represents the backbone that connects gateways
+// of the different Ring 1 networks.
+//
+// The ring 0 network corresponds to what would be ring 2 for region_id 0.
+// 10.0.0.0-10.0.255.255
+func RingZeroPrefix(region RegionID, zone ZoneID) (cidr netip.Prefix, err error) {
+	switch {
+	case !region.Valid():
+		err = ErrOutOfRange(region, "region")
+	case !zone.Valid():
+		err = ErrOutOfRange(zone, "zone")
+	default:
+		addr := unsafeRingZeroAddress(region, zone, 0)
+		cidr = netip.PrefixFrom(addr, RingZeroBits)
+	}
+
+	return cidr, err
+}
+
+// RingZeroAddress returns a Ring 0 address for a particular node.
+//
+// A ring 0 address looks like 10.0.(region_id << 4 + zone_id).(node_id)/20
+func RingZeroAddress(region RegionID, zone ZoneID, node NodeID) (addr netip.Addr, err error) {
+	switch {
+	case !region.Valid():
+		err = ErrOutOfRange(region, "region")
+	case !zone.Valid():
+		err = ErrOutOfRange(zone, "zone")
+	case !node.ValidZero():
+		err = ErrOutOfRange(node, "node")
+	default:
+		addr = unsafeRingZeroAddress(region, zone, node)
+	}
+
+	return addr, err
+}
+
+// DecodeRingZeroAddress attempts to extract region, zone and node identifiers
+// from a given ring 0 address.
+//
+// revive:disable:function-result-limit
+func DecodeRingZeroAddress(addr netip.Addr) (RegionID, ZoneID, NodeID, bool) {
+	// revive:enable:function-result-limit
+	k, r, z, n := DecodeAddress(addr)
+	if k == RingZero {
+		return r, z, NodeID(n), true
+	}
+
+	return 0, 0, 0, false
+}
+
+// RingOnePrefix represents a (virtual) local network of a zone.
+//
+// Ring 1 is `10.(region_id).(zone_id << 4).(node_id)/20` network
+// grouped under what would be Ring 2 for region_id 0.
+// There are 12 bits worth of nodes but nodes under 255 are special
+// as they also get a slot on Ring 0.
+func RingOnePrefix(region RegionID, zone ZoneID) (cidr netip.Prefix, err error) {
+	switch {
+	case !region.Valid():
+		err = ErrOutOfRange(region, "region")
+	case !zone.Valid():
+		err = ErrOutOfRange(zone, "zone")
+	default:
+		addr := unsafeRingOneAddress(region, zone, 0)
+		cidr = netip.PrefixFrom(addr, RingOneBits)
+	}
+	return cidr, err
+}
+
+// RingOneAddress returns a Ring 1 address for a particular node.
+//
+// A ring 1 address is `10.(region_id).(zone_id << 4).(node_id)/20`
+// but the node_id can take up to 12 bits.
+func RingOneAddress(region RegionID, zone ZoneID, node NodeID) (addr netip.Addr, err error) {
+	switch {
+	case !region.Valid():
+		err = ErrOutOfRange(region, "region")
+	case !zone.Valid():
+		err = ErrOutOfRange(zone, "zone")
+	case !node.Valid():
+		err = ErrOutOfRange(node, "node")
+	default:
+		addr = unsafeRingOneAddress(region, zone, node)
+	}
+	return addr, err
+}
+
+// DecodeRingOneAddress attempts to extract region, zone and node identifiers
+// from a given ring 1 address.
+//
+// revive:disable:function-result-limit
+func DecodeRingOneAddress(addr netip.Addr) (RegionID, ZoneID, NodeID, bool) {
+	// revive:enable:function-result-limit
+	k, r, z, n := DecodeAddress(addr)
+	if k == RingOne {
+		return r, z, NodeID(n), r != 0 && z != 0
+	}
+
+	return 0, 0, 0, false
+}
+
+// RingTwoPrefix represents the services of a cluster
+//
+// Ring 2 subnets are of the form `10.(region_id).0.0/20`,
+// using the address space that would belong to the ring 3
+// region_id 0.
+func RingTwoPrefix(region RegionID) (cidr netip.Prefix, err error) {
+	switch {
+	case !region.Valid():
+		err = ErrOutOfRange(region, "region")
+	default:
+		addr := unsafeRingTwoAddress(region, 0)
+		cidr = netip.PrefixFrom(addr, RingTwoBits)
+	}
+	return cidr, err
+}
+
+// RingThreePrefix returns the subnet corresponding to
+// the pods of a cluster.
+//
+// Ring 3 is a `10.(region_id << 4).0.0/12` network
+func RingThreePrefix(region RegionID) (subnet netip.Prefix, err error) {
+	switch {
+	case !region.Valid():
+		err = ErrOutOfRange(region, "region")
+	default:
+		addr := unsafeRingThreeAddress(region, 0)
+		subnet = netip.PrefixFrom(addr, RingThreeBits)
+	}
+	return subnet, err
+}
+
+func unsafeRingZeroAddress(region RegionID, zone ZoneID, node NodeID) netip.Addr {
+	r := uint(region)
+	z := uint(zone)
+	n := uint(node)
+
+	return AddrFrom4(10, 0, r<<4+z, n)
+}
+
+func unsafeRingOneAddress(region RegionID, zone ZoneID, node NodeID) netip.Addr {
+	r := uint(region)
+	z := uint(zone)
+	n := uint(node)
+
+	n1 := n >> 8
+	n0 := n >> 0
+
+	return AddrFrom4(10, r, z<<4+n1, n0)
+}
+
+func unsafeRingTwoAddress(region RegionID, n uint) netip.Addr {
+	r := uint(region)
+
+	n1 := n >> 8
+	n0 := n >> 0
+
+	return AddrFrom4(10, r, n1, n0)
+}
+
+func unsafeRingThreeAddress(region RegionID, n uint) netip.Addr {
+	r := uint(region)
+
+	n2 := n >> 16
+	n1 := n >> 8
+	n0 := n >> 0
+
+	return AddrFrom4(10, r<<4+n2, n1, n0)
+}

pkg/rings/rings_test.go

@@ -0,0 +1,109 @@
+package rings
+
+import (
+	"fmt"
+	"net/netip"
+	"testing"
+)
+
+func TestRingZeroAddress(t *testing.T) {
+	RZNTest(t, "RingZeroAddress", RingZeroAddress, []RZNTestCase{
+		{1, 1, 50, MustParseAddr("10.0.17.50")},
+		{1, 2, 50, MustParseAddr("10.0.18.50")},
+		{2, 3, 1, MustParseAddr("10.0.35.1")},
+		{2, 3, 300, netip.Addr{}},
+	})
+}
+
+func TestRingOneAddress(t *testing.T) {
+	RZNTest(t, "RingOneAddress", RingOneAddress, []RZNTestCase{
+		{1, 1, 50, MustParseAddr("10.1.16.50")},
+		{1, 2, 50, MustParseAddr("10.1.32.50")},
+		{2, 3, 300, MustParseAddr("10.2.49.44")},
+		{1, 20, 50, netip.Addr{}},
+	})
+}
+
+type RZNTestCase struct {
+	region RegionID
+	zone   ZoneID
+	node   NodeID
+	addr   netip.Addr
+}
+
+func RZNTest(t *testing.T,
+	fnName string, fn func(RegionID, ZoneID, NodeID) (netip.Addr, error),
+	cases []RZNTestCase) {
+	//
+	for i, tc := range cases {
+		s := fmt.Sprintf("%s(%v, %v, %v)", fnName,
+			tc.region,
+			tc.zone,
+			tc.node,
+		)
+
+		addr, err := fn(tc.region, tc.zone, tc.node)
+
+		switch {
+		case !tc.addr.IsValid():
+			// expect error
+			if err != nil {
+				t.Logf("[%v/%v]: %s → %s", i, len(cases), s, err)
+			} else {
+				t.Errorf("ERROR: [%v/%v]: %s → %s (expected %s)", i, len(cases), s, addr, "error")
+			}
+		case err != nil:
+			t.Errorf("ERROR: [%v/%v]: %s → %s (expected %s)", i, len(cases), s, err, tc.addr)
+		case addr.Compare(tc.addr) != 0:
+			t.Errorf("ERROR: [%v/%v]: %s → %s (expected %s)", i, len(cases), s, addr, tc.addr)
+		default:
+			t.Logf("[%v/%v]: %s → %s", i, len(cases), s, addr)
+		}
+	}
+}
+
+func TestDecodeRingZeroAddress(t *testing.T) {
+	RZNDecodeTest(t, "DecodeRingZeroAddress", DecodeRingZeroAddress, []RZNDecodeTestCase{
+		{1, 1, 50, MustParseAddr("10.0.17.50"), true},
+		{1, 2, 50, MustParseAddr("10.0.18.50"), true},
+		{2, 3, 1, MustParseAddr("10.0.35.1"), true},
+	})
+}
+
+func TesDecodetRingOneAddress(t *testing.T) {
+	RZNDecodeTest(t, "DecodeRingOneAddress", DecodeRingOneAddress, []RZNDecodeTestCase{
+		{1, 1, 50, MustParseAddr("10.1.16.50"), true},
+		{1, 2, 50, MustParseAddr("10.1.32.50"), true},
+		{2, 3, 300, MustParseAddr("10.2.49.44"), true},
+	})
+}
+
+type RZNDecodeTestCase struct {
+	region RegionID
+	zone   ZoneID
+	node   NodeID
+	addr   netip.Addr
+	ok     bool
+}
+
+func RZNDecodeTest(t *testing.T,
+	fnName string, fn func(netip.Addr) (RegionID, ZoneID, NodeID, bool),
+	cases []RZNDecodeTestCase) {
+	//
+	for i, tc := range cases {
+		s := fmt.Sprintf("%s(%q)", fnName, tc.addr)
+
+		r, z, n, ok := fn(tc.addr)
+
+		switch {
+		case ok != tc.ok, r != tc.region, z != tc.zone, n != tc.node:
+			t.Errorf("ERROR: [%v/%v]: %s → %v %v %v %v (expected %v %v %v %v)",
+				i, len(cases), s,
+				r, z, n, ok,
+				tc.region, tc.zone, tc.node, tc.ok)
+		default:
+			t.Logf("[%v/%v]: %s → %v %v %v %v", i, len(cases), s,
+				r, z, n, ok)
+		}
+	}
+}