Removed the IPv6 prefix size limit for cluster-cidr

Signed-off-by: André Martins <aanm90@gmail.com>

pkg/controller/node/ipam/cidrset/cidr_set.go

@@ -43,8 +43,8 @@ const (
 	// TODO: https://github.com/kubernetes/kubernetes/issues/44918
 	// clusterSubnetMaxDiff limited to 16 due to the uncompressed bitmap
 	clusterSubnetMaxDiff = 16
-	// maximum 64 bits of prefix
+	// halfIPv6Len is the half of the IPv6 length
-	maxPrefixLength = 64
+	halfIPv6Len = net.IPv6len / 2
 )
 
 var (
@@ -60,7 +60,7 @@ func NewCIDRSet(clusterCIDR *net.IPNet, subNetMaskSize int) *CidrSet {
 	clusterMaskSize, _ := clusterMask.Size()
 
 	var maxCIDRs int
-	if ((clusterCIDR.IP.To4() == nil) && (subNetMaskSize-clusterMaskSize > clusterSubnetMaxDiff)) || (subNetMaskSize > maxPrefixLength) {
+	if (clusterCIDR.IP.To4() == nil) && (subNetMaskSize-clusterMaskSize > clusterSubnetMaxDiff) {
 		maxCIDRs = 0
 	} else {
 		maxCIDRs = 1 << uint32(subNetMaskSize-clusterMaskSize)
@@ -74,6 +74,48 @@ func NewCIDRSet(clusterCIDR *net.IPNet, subNetMaskSize int) *CidrSet {
 	}
 }
 
+// TODO: Remove this function when upgrading to go 1.9
+var len8tab = [256]uint8{
+	0x00, 0x01, 0x02, 0x02, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
+	0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
+	0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
+	0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
+	0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
+	0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
+	0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
+	0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
+	0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
+	0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
+	0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
+	0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
+	0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
+	0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
+	0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
+	0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
+}
+
+// TODO: Remove this function when upgrading to go 1.9
+// len64 returns the minimum number of bits required to represent x; the result is 0 for x == 0.
+func len64(x uint64) (n int) {
+	if x >= 1<<32 {
+		x >>= 32
+		n = 32
+	}
+	if x >= 1<<16 {
+		x >>= 16
+		n += 16
+	}
+	if x >= 1<<8 {
+		x >>= 8
+		n += 8
+	}
+	return n + int(len8tab[x])
+}
+
+// TODO: Remove this function when upgrading to go 1.9
+// leadingZeros64 returns the number of leading zero bits in x; the result is 64 for x == 0.
+func leadingZeros64(x uint64) int { return 64 - len64(x) }
+
 func (s *CidrSet) indexToCIDRBlock(index int) *net.IPNet {
 	var ip []byte
 	var mask int
@@ -89,10 +131,36 @@ func (s *CidrSet) indexToCIDRBlock(index int) *net.IPNet {
 		}
 	case s.clusterIP.To16() != nil:
 		{
-			j := uint64(index) << uint64(64-s.subNetMaskSize)
+			// leftClusterIP      |     rightClusterIP
-			ipInt := (binary.BigEndian.Uint64(s.clusterIP)) | j
+			// 2001:0DB8:1234:0000:0000:0000:0000:0000
-			ip = make([]byte, 16)
+			const v6NBits = 128
-			binary.BigEndian.PutUint64(ip, ipInt)
+			const halfV6NBits = v6NBits / 2
+			leftClusterIP := binary.BigEndian.Uint64(s.clusterIP[:halfIPv6Len])
+			rightClusterIP := binary.BigEndian.Uint64(s.clusterIP[halfIPv6Len:])
+
+			leftIP, rightIP := make([]byte, halfIPv6Len), make([]byte, halfIPv6Len)
+
+			if s.subNetMaskSize <= halfV6NBits {
+				// We only care about left side IP
+				leftClusterIP |= uint64(index) << uint(halfV6NBits-s.subNetMaskSize)
+			} else {
+				if s.clusterMaskSize < halfV6NBits {
+					// see how many bits are needed to reach the left side
+					btl := uint(s.subNetMaskSize - halfV6NBits)
+					// TODO: Replace this with math/bits.LeadingZeros64 when upgrading to go 1.9
+					indexMaxBit := uint(64 - leadingZeros64(uint64(index)))
+					if indexMaxBit > btl {
+						leftClusterIP |= uint64(index) >> btl
+					}
+				}
+				// the right side will be calculated the same way either the
+				// subNetMaskSize affects both left and right sides
+				rightClusterIP |= uint64(index) << uint(v6NBits-s.subNetMaskSize)
+			}
+			binary.BigEndian.PutUint64(leftIP, leftClusterIP)
+			binary.BigEndian.PutUint64(rightIP, rightClusterIP)
+
+			ip = append(leftIP, rightIP...)
 			mask = 128
 		}
 	}
@@ -159,8 +227,12 @@ func (s *CidrSet) getBeginingAndEndIndices(cidr *net.IPNet) (begin, end int, err
 			ipInt := binary.BigEndian.Uint32(cidr.IP) | (^binary.BigEndian.Uint32(cidr.Mask))
 			binary.BigEndian.PutUint32(ip, ipInt)
 		} else {
-			ipInt := binary.BigEndian.Uint64(cidr.IP) | (^binary.BigEndian.Uint64(cidr.Mask))
+			// ipIntLeft          |         ipIntRight
-			binary.BigEndian.PutUint64(ip, ipInt)
+			// 2001:0DB8:1234:0000:0000:0000:0000:0000
+			ipIntLeft := binary.BigEndian.Uint64(cidr.IP[:net.IPv6len/2]) | (^binary.BigEndian.Uint64(cidr.Mask[:net.IPv6len/2]))
+			ipIntRight := binary.BigEndian.Uint64(cidr.IP[net.IPv6len/2:]) | (^binary.BigEndian.Uint64(cidr.Mask[net.IPv6len/2:]))
+			binary.BigEndian.PutUint64(ip[:net.IPv6len/2], ipIntLeft)
+			binary.BigEndian.PutUint64(ip[net.IPv6len/2:], ipIntRight)
 		}
 		end, err = s.getIndexForCIDR(&net.IPNet{
 			IP:   net.IP(ip).Mask(subNetMask),
@@ -217,7 +289,10 @@ func (s *CidrSet) getIndexForIP(ip net.IP) (int, error) {
 		return int(cidrIndex), nil
 	}
 	if ip.To16() != nil {
-		cidrIndex := (binary.BigEndian.Uint64(s.clusterIP) ^ binary.BigEndian.Uint64(ip.To16())) >> uint64(64-s.subNetMaskSize)
+		bigIP := big.NewInt(0).SetBytes(s.clusterIP)
+		bigIP = bigIP.Xor(bigIP, big.NewInt(0).SetBytes(ip))
+		cidrIndexBig := bigIP.Rsh(bigIP, uint(net.IPv6len*8-s.subNetMaskSize))
+		cidrIndex := cidrIndexBig.Uint64()
 		if cidrIndex >= uint64(s.maxCIDRs) {
 			return 0, fmt.Errorf("CIDR: %v/%v is out of the range of CIDR allocator", ip, s.subNetMaskSize)
 		}

pkg/controller/node/ipam/cidrset/cidr_set_test.go

@@ -93,42 +93,105 @@ func TestIndexToCIDRBlock(t *testing.T) {
 			subnetMaskSize: 24,
 			index:          0,
 			CIDRBlock:      "127.123.0.0/24",
-			description:    "Index with IPv4",
+			description:    "1st IP address indexed with IPv4",
 		},
 		{
 			clusterCIDRStr: "127.123.0.0/16",
 			subnetMaskSize: 24,
 			index:          15,
 			CIDRBlock:      "127.123.15.0/24",
-			description:    "Index with IPv4",
+			description:    "16th IP address indexed with IPv4",
 		},
 		{
 			clusterCIDRStr: "192.168.5.219/28",
 			subnetMaskSize: 32,
 			index:          5,
 			CIDRBlock:      "192.168.5.213/32",
-			description:    "Index with IPv4",
+			description:    "5th IP address indexed with IPv4",
 		},
 		{
 			clusterCIDRStr: "2001:0db8:1234:3::/48",
 			subnetMaskSize: 64,
 			index:          0,
 			CIDRBlock:      "2001:db8:1234::/64",
-			description:    "Index with IPv6",
+			description:    "1st IP address indexed with IPv6 /64",
 		},
 		{
 			clusterCIDRStr: "2001:0db8:1234::/48",
 			subnetMaskSize: 64,
 			index:          15,
 			CIDRBlock:      "2001:db8:1234:f::/64",
-			description:    "Index with IPv6",
+			description:    "16th IP address indexed with IPv6 /64",
 		},
 		{
 			clusterCIDRStr: "2001:0db8:85a3::8a2e:0370:7334/50",
 			subnetMaskSize: 63,
 			index:          6425,
 			CIDRBlock:      "2001:db8:85a3:3232::/63",
-			description:    "Index with IPv6",
+			description:    "6426th IP address indexed with IPv6 /63",
+		},
+		{
+			clusterCIDRStr: "2001:0db8::/32",
+			subnetMaskSize: 48,
+			index:          0,
+			CIDRBlock:      "2001:db8::/48",
+			description:    "1st IP address indexed with IPv6 /48",
+		},
+		{
+			clusterCIDRStr: "2001:0db8::/32",
+			subnetMaskSize: 48,
+			index:          15,
+			CIDRBlock:      "2001:db8:f::/48",
+			description:    "16th IP address indexed with IPv6 /48",
+		},
+		{
+			clusterCIDRStr: "2001:0db8:85a3::8a2e:0370:7334/32",
+			subnetMaskSize: 48,
+			index:          6425,
+			CIDRBlock:      "2001:db8:1919::/48",
+			description:    "6426th IP address indexed with IPv6 /48",
+		},
+		{
+			clusterCIDRStr: "2001:0db8:1234:ff00::/56",
+			subnetMaskSize: 72,
+			index:          0,
+			CIDRBlock:      "2001:db8:1234:ff00::/72",
+			description:    "1st IP address indexed with IPv6 /72",
+		},
+		{
+			clusterCIDRStr: "2001:0db8:1234:ff00::/56",
+			subnetMaskSize: 72,
+			index:          15,
+			CIDRBlock:      "2001:db8:1234:ff00:f00::/72",
+			description:    "16th IP address indexed with IPv6 /72",
+		},
+		{
+			clusterCIDRStr: "2001:0db8:1234:ff00::0370:7334/56",
+			subnetMaskSize: 72,
+			index:          6425,
+			CIDRBlock:      "2001:db8:1234:ff19:1900::/72",
+			description:    "6426th IP address indexed with IPv6 /72",
+		},
+		{
+			clusterCIDRStr: "2001:0db8:1234:0:1234::/80",
+			subnetMaskSize: 96,
+			index:          0,
+			CIDRBlock:      "2001:db8:1234:0:1234::/96",
+			description:    "1st IP address indexed with IPv6 /96",
+		},
+		{
+			clusterCIDRStr: "2001:0db8:1234:0:1234::/80",
+			subnetMaskSize: 96,
+			index:          15,
+			CIDRBlock:      "2001:db8:1234:0:1234:f::/96",
+			description:    "16th IP address indexed with IPv6 /96",
+		},
+		{
+			clusterCIDRStr: "2001:0db8:1234:ff00::0370:7334/80",
+			subnetMaskSize: 96,
+			index:          6425,
+			CIDRBlock:      "2001:db8:1234:ff00:0:1919::/96",
+			description:    "6426th IP address indexed with IPv6 /96",
 		},
 	}
 	for _, tc := range cases {
@@ -612,12 +675,6 @@ func TestCIDRSetv6(t *testing.T) {
 			expectErr:      true,
 			description:    "Max cluster subnet size with IPv6",
 		},
-		{
-			clusterCIDRStr: "beef:1234::/60",
-			subNetMaskSize: 65,
-			expectErr:      true,
-			description:    "Max prefix length with IPv6",
-		},
 		{
 			clusterCIDRStr: "2001:beef:1234:369b::/60",
 			subNetMaskSize: 64,