From 873ea8a2244dce9d71af7aff5d5e4f3fe096b50e Mon Sep 17 00:00:00 2001
From: Alessandro Boch <aboch@docker.com>
Date: Fri, 12 Jun 2015 12:43:18 -0700
Subject: [PATCH] Add libnetwork ipam implementation

Signed-off-by: Alessandro Boch <aboch@docker.com>
---
 libnetwork/ipam/allocator.go      | 441 ++++++++++++++++++++++++
 libnetwork/ipam/allocator_test.go | 543 ++++++++++++++++++++++++++++++
 2 files changed, 984 insertions(+)
 create mode 100644 libnetwork/ipam/allocator.go
 create mode 100644 libnetwork/ipam/allocator_test.go

diff --git a/libnetwork/ipam/allocator.go b/libnetwork/ipam/allocator.go
new file mode 100644
index 0000000000..3c52853b8a
--- /dev/null
+++ b/libnetwork/ipam/allocator.go
@@ -0,0 +1,441 @@
+package ipam
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/docker/libnetwork/bitseq"
+)
+
+const (
+	// The biggest configurable host subnets
+	minNetSize   = 8
+	minNetSizeV6 = 64
+	// The effective network size for v6
+	minNetSizeV6Eff = 96
+	// The size of the host subnet used internally, it's the most granular sequence addresses
+	defaultInternalHostSize = 16
+)
+
+// Allocator provides per address space ipv4/ipv6 book keeping
+type Allocator struct {
+	// The internal subnets host size
+	internalHostSize int
+	// Static subnet information
+	subnetsInfo map[subnetKey]*subnetData
+	// Allocated addresses in each address space's internal subnet
+	addresses map[isKey]*bitmask
+}
+
+// NewAllocator returns an instance of libnetwork ipam
+func NewAllocator() *Allocator {
+	a := &Allocator{}
+	a.subnetsInfo = make(map[subnetKey]*subnetData)
+	a.addresses = make(map[isKey]*bitmask)
+	a.internalHostSize = defaultInternalHostSize
+	return a
+}
+
+// Pointer to the configured subnets in each address space
+type subnetKey struct {
+	addressSpace AddressSpace
+	subnet       string
+}
+
+// Pointer to the internal subnets in each address space
+type isKey subnetKey
+
+// The structs contains the configured subnet information
+// along with the pointers to the respective internal subnets
+type subnetData struct {
+	info        *SubnetInfo // Configured subnet
+	intSubKeyes []*isKey    // Pointers to child internal subnets
+}
+
+// The structs containing the address allocation bitmask for the internal subnet.
+// The bitmask is stored a run-length encoded seq.Sequence of 4 bytes blcoks.
+type bitmask struct {
+	subnet        *net.IPNet
+	addressMask   *bitseq.Sequence
+	freeAddresses int
+}
+
+type ipVersion int
+
+const (
+	v4 = 4
+	v6 = 6
+)
+
+/*******************
+ * IPAMConf Contract
+ ********************/
+
+// AddSubnet adds a subnet for the specified address space
+func (a *Allocator) AddSubnet(addrSpace AddressSpace, subnetInfo *SubnetInfo) error {
+	// Sanity check
+	if addrSpace == "" {
+		return ErrInvalidAddressSpace
+	}
+	if subnetInfo == nil || subnetInfo.Subnet == nil {
+		return ErrInvalidSubnet
+	}
+	if a.contains(addrSpace, subnetInfo) {
+		return ErrOverlapSubnet
+	}
+
+	// Sanity check and size adjustment for v6
+	subnetToSplit, err := adjustAndCheckSubnetSize(subnetInfo.Subnet)
+	if err != nil {
+		return err
+	}
+
+	// Convert to smaller internal subnets (if needed)
+	subnetList, err := getInternalSubnets(subnetToSplit, a.internalHostSize)
+	if err != nil {
+		return err
+	}
+
+	// Store the configured subnet information
+	subnetKey := subnetKey{addrSpace, subnetInfo.Subnet.String()}
+	info := &subnetData{info: subnetInfo, intSubKeyes: make([]*isKey, len(subnetList))}
+	a.subnetsInfo[subnetKey] = info
+
+	// Create and insert the internal subnet(s) addresses masks into the address database
+	for i, sub := range subnetList {
+		ones, bits := sub.Mask.Size()
+		numAddresses := 1 << uint(bits-ones)
+
+		// Create and store internal subnet key into parent subnet handle
+		smallKey := &isKey{addrSpace, sub.String()}
+		info.intSubKeyes[i] = smallKey
+
+		// Add the new address masks
+		a.addresses[*smallKey] = &bitmask{
+			subnet:        sub,
+			addressMask:   bitseq.New(uint32(numAddresses)),
+			freeAddresses: numAddresses,
+		}
+	}
+
+	return nil
+}
+
+// Check subnets size. In case configured subnet is v6 and host size is
+// greater than 32 bits, adjust subnet to /96.
+func adjustAndCheckSubnetSize(subnet *net.IPNet) (*net.IPNet, error) {
+	ones, bits := subnet.Mask.Size()
+	if v6 == getAddressVersion(subnet.IP) {
+		if ones < minNetSizeV6 {
+			return nil, ErrInvalidSubnet
+		}
+		if ones < minNetSizeV6Eff {
+			newMask := net.CIDRMask(minNetSizeV6Eff, bits)
+			return &net.IPNet{IP: subnet.IP, Mask: newMask}, nil
+		}
+	} else {
+		if ones < minNetSize {
+			return nil, ErrInvalidSubnet
+		}
+	}
+	return subnet, nil
+}
+
+// Checks whether the passed subnet is a superset or subset of any of the subset in the db
+func (a *Allocator) contains(space AddressSpace, subInfo *SubnetInfo) bool {
+	for k, v := range a.subnetsInfo {
+		if space == k.addressSpace {
+			if subInfo.Subnet.Contains(v.info.Subnet.IP) ||
+				v.info.Subnet.Contains(subInfo.Subnet.IP) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// Splits the passed subnet into N internal subnets with host size equal to internalHostSize.
+// If the subnet's host size is equal to or smaller than internalHostSize, there won't be any
+// split and the return list will contain only the passed subnet.
+func getInternalSubnets(subnet *net.IPNet, internalHostSize int) ([]*net.IPNet, error) {
+	var subnetList []*net.IPNet
+
+	// Get network/host subnet information
+	netBits, bits := subnet.Mask.Size()
+	hostBits := bits - netBits
+
+	extraBits := hostBits - internalHostSize
+	if extraBits <= 0 {
+		subnetList = make([]*net.IPNet, 1)
+		subnetList[0] = subnet
+	} else {
+		// Split in smaller internal subnets
+		numIntSubs := 1 << uint(extraBits)
+		subnetList = make([]*net.IPNet, numIntSubs)
+
+		// Construct one copy of the internal subnets's mask
+		intNetBits := bits - internalHostSize
+		intMask := net.CIDRMask(intNetBits, bits)
+
+		// Construct the prefix portion for each internal subnet
+		for i := 0; i < numIntSubs; i++ {
+			intIP := make([]byte, len(subnet.IP))
+			copy(intIP, subnet.IP) // IPv6 is too big, just work on the extra portion
+			addIntToIP(intIP, i<<uint(internalHostSize))
+			subnetList[i] = &net.IPNet{IP: intIP, Mask: intMask}
+		}
+	}
+	return subnetList, nil
+}
+
+// RemoveSubnet removes the subnet from the specified address space
+func (a *Allocator) RemoveSubnet(addrSpace AddressSpace, subnet *net.IPNet) error {
+	if addrSpace == "" {
+		return ErrInvalidAddressSpace
+	}
+	if subnet == nil {
+		return ErrInvalidSubnet
+	}
+
+	// Look for the respective subnet configuration data
+	// Remove it along with the internal subnets
+	subKey := subnetKey{addrSpace, subnet.String()}
+	subData, ok := a.subnetsInfo[subKey]
+	if !ok {
+		return ErrSubnetNotFound
+	}
+
+	for _, key := range subData.intSubKeyes {
+		delete(a.addresses, *key)
+	}
+
+	delete(a.subnetsInfo, subKey)
+
+	return nil
+
+}
+
+// AddVendorInfo adds vendor specific data
+func (a *Allocator) AddVendorInfo([]byte) error {
+	// no op for us
+	return nil
+}
+
+/****************
+ * IPAM Contract
+ ****************/
+
+// Request allows requesting an IPv4 address from the specified address space
+func (a *Allocator) Request(addrSpace AddressSpace, req *AddressRequest) (*AddressResponse, error) {
+	return a.request(addrSpace, req, v4)
+}
+
+// RequestV6 requesting an IPv6 address from the specified address space
+func (a *Allocator) RequestV6(addrSpace AddressSpace, req *AddressRequest) (*AddressResponse, error) {
+	return a.request(addrSpace, req, v6)
+}
+
+func (a *Allocator) request(addrSpace AddressSpace, req *AddressRequest, version ipVersion) (*AddressResponse, error) {
+	// Empty response
+	response := &AddressResponse{}
+
+	// Sanity check
+	if addrSpace == "" {
+		return response, ErrInvalidAddressSpace
+	}
+
+	// Validate request
+	if err := req.Validate(); err != nil {
+		return response, err
+	}
+
+	// Check ip version congruence
+	if &req.Subnet != nil && version != getAddressVersion(req.Subnet.IP) {
+		return response, ErrInvalidRequest
+	}
+
+	// Look for an address
+	ip, _, err := a.reserveAddress(addrSpace, &req.Subnet, req.Address, version)
+	if err == nil {
+		// Populate response
+		response.Address = ip
+		response.Subnet = *a.subnetsInfo[subnetKey{addrSpace, req.Subnet.String()}].info
+	}
+
+	return response, err
+}
+
+// Release allows releasing the address from the specified address space
+func (a *Allocator) Release(addrSpace AddressSpace, address net.IP) {
+	if address == nil {
+		return
+	}
+	ver := getAddressVersion(address)
+	if ver == v4 {
+		address = address.To4()
+	}
+	for _, subKey := range a.getSubnetList(addrSpace, ver) {
+		sub := a.addresses[*subKey].subnet
+		if sub.Contains(address) {
+			// Retrieve correspondent ordinal in the subnet
+			space := a.addresses[isKey{addrSpace, sub.String()}]
+			ordinal := ipToInt(getHostPortionIP(address, space.subnet))
+			// Release it
+			space.addressMask = bitseq.PushReservation(ordinal/8, ordinal%8, space.addressMask, true)
+			space.freeAddresses++
+			return
+		}
+	}
+}
+
+func (a *Allocator) reserveAddress(addrSpace AddressSpace, subnet *net.IPNet, prefAddress net.IP, ver ipVersion) (net.IP, *net.IPNet, error) {
+	var keyList []*isKey
+
+	// Get the list of pointers to the internal subnets
+	if subnet != nil {
+		keyList = a.subnetsInfo[subnetKey{addrSpace, subnet.String()}].intSubKeyes
+	} else {
+		keyList = a.getSubnetList(addrSpace, ver)
+	}
+	if len(keyList) == 0 {
+		return nil, nil, ErrNoAvailableSubnet
+	}
+
+	for _, key := range keyList {
+		smallSubnet := a.addresses[*key]
+		address, err := a.getAddress(smallSubnet, prefAddress, ver)
+		if err == nil {
+			return address, subnet, nil
+		}
+	}
+
+	return nil, nil, ErrNoAvailableIPs
+}
+
+// Get the list of available internal subnets for the specified address space and the desired ip version
+func (a *Allocator) getSubnetList(addrSpace AddressSpace, ver ipVersion) []*isKey {
+	var list [1024]*isKey
+	ind := 0
+	for subKey := range a.addresses {
+		_, s, _ := net.ParseCIDR(subKey.subnet)
+		subVer := getAddressVersion(s.IP)
+		if subKey.addressSpace == addrSpace && subVer == ver {
+			list[ind] = &subKey
+			ind++
+		}
+	}
+	return list[0:ind]
+}
+
+func (a *Allocator) getAddress(smallSubnet *bitmask, prefAddress net.IP, ver ipVersion) (net.IP, error) {
+	var (
+		bytePos, bitPos int
+	)
+	// Look for free IP, skip .0 and .255, they will be automatically reserved
+again:
+	if smallSubnet.freeAddresses <= 0 {
+		return nil, ErrNoAvailableIPs
+	}
+	if prefAddress == nil {
+		bytePos, bitPos = bitseq.GetFirstAvailable(smallSubnet.addressMask)
+	} else {
+		ordinal := ipToInt(getHostPortionIP(prefAddress, smallSubnet.subnet))
+		bytePos, bitPos = bitseq.CheckIfAvailable(smallSubnet.addressMask, ordinal)
+	}
+	if bytePos == -1 {
+		return nil, ErrNoAvailableIPs
+	}
+
+	// Lock it
+	smallSubnet.addressMask = bitseq.PushReservation(bytePos, bitPos, smallSubnet.addressMask, false)
+	smallSubnet.freeAddresses--
+
+	// Build IP ordinal
+	ordinal := bitPos + bytePos*8
+
+	// For v4, let reservation of .0 and .255 happen automatically
+	if ver == v4 && !isValidIP(ordinal) {
+		goto again
+	}
+
+	// Convert IP ordinal for this subnet into IP address
+	return generateAddress(ordinal, smallSubnet.subnet), nil
+}
+
+// DumpDatabase dumps the internal info
+func (a *Allocator) DumpDatabase() {
+	for _, config := range a.subnetsInfo {
+		fmt.Printf("\n\n%s:", config.info.Subnet.String())
+		for _, internKey := range config.intSubKeyes {
+			bm := a.addresses[*internKey]
+			fmt.Printf("\n\t%s: %s\n\t%d", bm.subnet, bm.addressMask, bm.freeAddresses)
+		}
+	}
+}
+
+// It generates the ip address in the passed subnet specified by
+// the passed host address ordinal
+func generateAddress(ordinal int, network *net.IPNet) net.IP {
+	var address [16]byte
+
+	// Get network portion of IP
+	if network.IP.To4() != nil {
+		copy(address[:], network.IP.To4())
+	} else {
+		copy(address[:], network.IP)
+	}
+
+	end := len(network.Mask)
+	addIntToIP(address[:end], ordinal)
+
+	return net.IP(address[:end])
+}
+
+func getAddressVersion(ip net.IP) ipVersion {
+	if ip.To4() == nil {
+		return v6
+	}
+	return v4
+}
+
+// .0 and .255 will return false
+func isValidIP(i int) bool {
+	lastByte := i & 0xff
+	return lastByte != 0xff && lastByte != 0
+}
+
+// Adds the ordinal IP to the current array
+// 192.168.0.0 + 53 => 192.168.53
+func addIntToIP(array []byte, ordinal int) {
+	for i := len(array) - 1; i >= 0; i-- {
+		array[i] |= (byte)(ordinal & 0xff)
+		ordinal >>= 8
+	}
+}
+
+// Convert an ordinal to the respective IP address
+func ipToInt(ip []byte) int {
+	value := 0
+	for i := 0; i < len(ip); i++ {
+		j := len(ip) - 1 - i
+		value += int(ip[i]) << uint(j*8)
+	}
+	return value
+}
+
+// Given an address and subnet, returns the host portion address
+func getHostPortionIP(address net.IP, subnet *net.IPNet) net.IP {
+	hostPortion := make([]byte, len(address))
+	for i := 0; i < len(subnet.Mask); i++ {
+		hostPortion[i] = address[i] &^ subnet.Mask[i]
+	}
+	return hostPortion
+}
+
+func printLine(head *bitseq.Sequence) {
+	fmt.Println()
+	for head != nil {
+		fmt.Printf("-")
+		head = head.Next
+	}
+}
diff --git a/libnetwork/ipam/allocator_test.go b/libnetwork/ipam/allocator_test.go
new file mode 100644
index 0000000000..e72342015e
--- /dev/null
+++ b/libnetwork/ipam/allocator_test.go
@@ -0,0 +1,543 @@
+package ipam
+
+import (
+	"fmt"
+	"net"
+	"testing"
+	"time"
+
+	"github.com/docker/libnetwork/bitseq"
+)
+
+func getAllocator(subnet *net.IPNet) *Allocator {
+	a := NewAllocator()
+	a.AddSubnet("default", &SubnetInfo{Subnet: subnet})
+	return a
+}
+
+func TestInt2IP2IntConversion(t *testing.T) {
+	for i := 0; i < 256*256*256; i++ {
+		var array [4]byte // new array at each cycle
+		addIntToIP(array[:], i)
+		j := ipToInt(array[:])
+		if j != i {
+			t.Fatalf("Failed to convert ordinal %d to IP % x and back to ordinal. Got %d", i, array, j)
+		}
+	}
+}
+
+func TestIsValid(t *testing.T) {
+	list := []int{0, 255, 256, 511, 512, 767, 768}
+	for _, i := range list {
+		if isValidIP(i) {
+			t.Fatalf("Failed to detect invalid IPv4 ordinal: %d", i)
+		}
+	}
+
+	list = []int{1, 254, 257, 258, 510, 513, 769, 770}
+	for _, i := range list {
+		if !isValidIP(i) {
+			t.Fatalf("Marked valid ipv4 as invalid: %d", i)
+		}
+	}
+}
+
+func TestGetAddressVersion(t *testing.T) {
+	if v4 != getAddressVersion(net.ParseIP("172.28.30.112")) {
+		t.Fatalf("Failed to detect IPv4 version")
+	}
+	if v4 != getAddressVersion(net.ParseIP("0.0.0.1")) {
+		t.Fatalf("Failed to detect IPv4 version")
+	}
+	if v6 != getAddressVersion(net.ParseIP("ff01::1")) {
+		t.Fatalf("Failed to detect IPv6 version")
+	}
+	if v6 != getAddressVersion(net.ParseIP("2001:56::76:51")) {
+		t.Fatalf("Failed to detect IPv6 version")
+	}
+}
+
+func TestAddSubnets(t *testing.T) {
+	a := NewAllocator()
+
+	_, sub0, _ := net.ParseCIDR("10.0.0.0/8")
+	err := a.AddSubnet("default", &SubnetInfo{Subnet: sub0})
+	if err != nil {
+		t.Fatalf("Unexpected failure in adding subent")
+	}
+
+	err = a.AddSubnet("abc", &SubnetInfo{Subnet: sub0})
+	if err != nil {
+		t.Fatalf("Unexpected failure in adding overlapping subents to different address spaces")
+	}
+
+	err = a.AddSubnet("abc", &SubnetInfo{Subnet: sub0})
+	if err == nil {
+		t.Fatalf("Failed to detect overlapping subnets: %s and %s", sub0, sub0)
+	}
+
+	_, sub1, _ := net.ParseCIDR("10.20.2.0/24")
+	err = a.AddSubnet("default", &SubnetInfo{Subnet: sub1})
+	if err == nil {
+		t.Fatalf("Failed to detect overlapping subnets: %s and %s", sub0, sub1)
+	}
+
+	_, sub2, _ := net.ParseCIDR("10.128.0.0/9")
+	err = a.AddSubnet("default", &SubnetInfo{Subnet: sub2})
+	if err == nil {
+		t.Fatalf("Failed to detect overlapping subnets: %s and %s", sub1, sub2)
+	}
+
+	_, sub6, err := net.ParseCIDR("1003:1:2:3:4:5:6::/112")
+	if err != nil {
+		t.Fatalf("Wrong input, Can't proceed: %s", err.Error())
+	}
+	err = a.AddSubnet("default", &SubnetInfo{Subnet: sub6})
+	if err != nil {
+		t.Fatalf("Failed to add v6 subnet: %s", err.Error())
+	}
+
+	_, sub6, err = net.ParseCIDR("1003:1:2:3::/64")
+	if err != nil {
+		t.Fatalf("Wrong input, Can't proceed: %s", err.Error())
+	}
+	err = a.AddSubnet("default", &SubnetInfo{Subnet: sub6})
+	if err == nil {
+		t.Fatalf("Failed to detect overlapping v6 subnet")
+	}
+}
+
+func TestAdjustAndCheckSubnet(t *testing.T) {
+	_, sub6, _ := net.ParseCIDR("1003:1:2:300::/63")
+	_, err := adjustAndCheckSubnetSize(sub6)
+	if err == nil {
+		t.Fatalf("Failed detect too big v6 subnet")
+	}
+
+	_, sub, _ := net.ParseCIDR("192.0.0.0/7")
+	_, err = adjustAndCheckSubnetSize(sub)
+	if err == nil {
+		t.Fatalf("Failed detect too big v4 subnet")
+	}
+
+	subnet := "1004:1:2:6::/64"
+	_, sub6, _ = net.ParseCIDR(subnet)
+	subnetToSplit, err := adjustAndCheckSubnetSize(sub6)
+	if err != nil {
+		t.Fatalf("Unexpected error returned by adjustAndCheckSubnetSize()")
+	}
+	ones, _ := subnetToSplit.Mask.Size()
+	if ones < minNetSizeV6Eff {
+		t.Fatalf("Wrong effective network size for %s. Expected: %d. Got: %d", subnet, minNetSizeV6Eff, ones)
+	}
+}
+
+func TestRemoveSubnet(t *testing.T) {
+	a := NewAllocator()
+
+	input := []struct {
+		addrSpace AddressSpace
+		subnet    string
+	}{
+		{"default", "192.168.0.0/16"},
+		{"default", "172.17.0.0/16"},
+		{"default", "10.0.0.0/8"},
+		{"default", "2002:1:2:3:4:5:ffff::/112"},
+		{"splane", "172.17.0.0/16"},
+		{"splane", "10.0.0.0/8"},
+		{"splane", "2002:1:2:3:4:5:6::/112"},
+		{"splane", "2002:1:2:3:4:5:ffff::/112"},
+	}
+
+	for _, i := range input {
+		_, sub, err := net.ParseCIDR(i.subnet)
+		if err != nil {
+			t.Fatalf("Wrong input, Can't proceed: %s", err.Error())
+		}
+		err = a.AddSubnet(i.addrSpace, &SubnetInfo{Subnet: sub})
+		if err != nil {
+			t.Fatalf("Failed to apply input. Can't proceed: %s", err.Error())
+		}
+	}
+
+	_, sub, _ := net.ParseCIDR("172.17.0.0/16")
+	a.RemoveSubnet("default", sub)
+	if len(a.subnetsInfo) != 7 {
+		t.Fatalf("Failed to remove subnet info")
+	}
+	list := a.getSubnetList("default", v4)
+	if len(list) != 257 {
+		t.Fatalf("Failed to effectively remove subnet address space")
+	}
+
+	_, sub, _ = net.ParseCIDR("2002:1:2:3:4:5:ffff::/112")
+	a.RemoveSubnet("default", sub)
+	if len(a.subnetsInfo) != 6 {
+		t.Fatalf("Failed to remove subnet info")
+	}
+	list = a.getSubnetList("default", v6)
+	if len(list) != 0 {
+		t.Fatalf("Failed to effectively remove subnet address space")
+	}
+
+	_, sub, _ = net.ParseCIDR("2002:1:2:3:4:5:6::/112")
+	a.RemoveSubnet("splane", sub)
+	if len(a.subnetsInfo) != 5 {
+		t.Fatalf("Failed to remove subnet info")
+	}
+	list = a.getSubnetList("splane", v6)
+	if len(list) != 1 {
+		t.Fatalf("Failed to effectively remove subnet address space")
+	}
+}
+
+func TestGetInternalSubnets(t *testing.T) {
+	// This function tests the splitting of a parent subnet in small host subnets.
+	// The splitting is controlled by the max host size, which is the first parameter
+	// passed to the function. It basically says if the parent subnet host size is
+	// greater than the max host size, split the parent subnet into N internal small
+	// subnets with host size = max host size to cover the same address space.
+
+	input := []struct {
+		internalHostSize int
+		parentSubnet     string
+		firstIntSubnet   string
+		lastIntSubnet    string
+	}{
+		// Test 8 bits prefix network
+		{24, "10.0.0.0/8", "10.0.0.0/8", "10.0.0.0/8"},
+		{16, "10.0.0.0/8", "10.0.0.0/16", "10.255.0.0/16"},
+		{8, "10.0.0.0/8", "10.0.0.0/24", "10.255.255.0/24"},
+		// Test 16 bits prefix network
+		{16, "192.168.0.0/16", "192.168.0.0/16", "192.168.0.0/16"},
+		{8, "192.168.0.0/16", "192.168.0.0/24", "192.168.255.0/24"},
+		// Test 24 bits prefix network
+		{16, "192.168.57.0/24", "192.168.57.0/24", "192.168.57.0/24"},
+		{8, "192.168.57.0/24", "192.168.57.0/24", "192.168.57.0/24"},
+		// Test non byte multiple host size
+		{24, "10.0.0.0/8", "10.0.0.0/8", "10.0.0.0/8"},
+		{20, "10.0.0.0/12", "10.0.0.0/12", "10.0.0.0/12"},
+		{20, "10.128.0.0/12", "10.128.0.0/12", "10.128.0.0/12"},
+		{12, "10.16.0.0/16", "10.16.0.0/20", "10.16.240.0/20"},
+		{13, "10.0.0.0/8", "10.0.0.0/19", "10.255.224.0/19"},
+		{15, "10.0.0.0/8", "10.0.0.0/17", "10.255.128.0/17"},
+		// Test v6 network
+		{16, "2002:1:2:3:4:5:6000::/110", "2002:1:2:3:4:5:6000:0/112", "2002:1:2:3:4:5:6003:0/112"},
+		{16, "2002:1:2:3:4:5:ff00::/104", "2002:1:2:3:4:5:ff00:0/112", "2002:1:2:3:4:5:ffff:0/112"},
+		{12, "2002:1:2:3:4:5:ffff::/112", "2002:1:2:3:4:5:ffff:0/116", "2002:1:2:3:4:5:ffff:f000/116"},
+		{11, "2002:1:2:3:4:5:ffff::/112", "2002:1:2:3:4:5:ffff:0/117", "2002:1:2:3:4:5:ffff:f800/117"},
+	}
+
+	for _, d := range input {
+		assertInternalSubnet(t, d.internalHostSize, d.parentSubnet, d.firstIntSubnet, d.lastIntSubnet)
+	}
+
+}
+
+func TestGetAddress(t *testing.T) {
+	input := []string{
+		/*"10.0.0.0/8", "10.0.0.0/9", */ "10.0.0.0/10", "10.0.0.0/11", "10.0.0.0/12", "10.0.0.0/13", "10.0.0.0/14",
+		"10.0.0.0/15", "10.0.0.0/16", "10.0.0.0/17", "10.0.0.0/18", "10.0.0.0/19", "10.0.0.0/20", "10.0.0.0/21",
+		"10.0.0.0/22", "10.0.0.0/23", "10.0.0.0/24", "10.0.0.0/25", "10.0.0.0/26", "10.0.0.0/27", "10.0.0.0/28",
+		"10.0.0.0/29", "10.0.0.0/30", "10.0.0.0/31"}
+
+	for _, subnet := range input {
+		assertGetAddress(t, subnet)
+	}
+}
+
+func TestGetSubnetList(t *testing.T) {
+	a := NewAllocator()
+	input := []struct {
+		addrSpace AddressSpace
+		subnet    string
+	}{
+		{"default", "192.168.0.0/16"},
+		{"default", "172.17.0.0/16"},
+		{"default", "10.0.0.0/8"},
+		{"default", "2002:1:2:3:4:5:6::/112"},
+		{"default", "2002:1:2:3:4:5:ffff::/112"},
+		{"splane", "172.17.0.0/16"},
+		{"splane", "10.0.0.0/8"},
+		{"splane", "2002:1:2:3:4:5:ff00::/104"},
+	}
+
+	for _, i := range input {
+		_, sub, err := net.ParseCIDR(i.subnet)
+		if err != nil {
+			t.Fatalf("Wrong input, Can't proceed: %s", err.Error())
+		}
+		err = a.AddSubnet(i.addrSpace, &SubnetInfo{Subnet: sub})
+		if err != nil {
+			t.Fatalf("Failed to apply input. Can't proceed: %s", err.Error())
+		}
+	}
+
+	list := a.getSubnetList("default", v4)
+	if len(list) != 258 {
+		t.Fatalf("Incorrect number of internal subnets for ipv4 version. Expected 258. Got %d.", len(list))
+	}
+	list = a.getSubnetList("splane", v4)
+	if len(list) != 257 {
+		t.Fatalf("Incorrect number of internal subnets for ipv4 version. Expected 257. Got %d.", len(list))
+	}
+
+	list = a.getSubnetList("default", v6)
+	if len(list) != 2 {
+		t.Fatalf("Incorrect number of internal subnets for ipv6 version. Expected 2. Got %d.", len(list))
+	}
+	list = a.getSubnetList("splane", v6)
+	if len(list) != 256 {
+		t.Fatalf("Incorrect number of internal subnets for ipv6 version. Expected 256. Got %d.", len(list))
+	}
+
+}
+
+func TestRequestSyntaxCheck(t *testing.T) {
+	var (
+		a        = NewAllocator()
+		subnet   = "192.168.0.0/16"
+		addSpace = AddressSpace("green")
+	)
+
+	// Add subnet and create base request
+	_, sub, _ := net.ParseCIDR(subnet)
+	a.AddSubnet(addSpace, &SubnetInfo{Subnet: sub})
+	req := &AddressRequest{Subnet: *sub}
+
+	// Empty address space request
+	_, err := a.Request("", req)
+	if err == nil {
+		t.Fatalf("Failed to detect wrong request: empty address space")
+	}
+
+	// Preferred address from different subnet in request
+	req.Address = net.ParseIP("172.17.0.23")
+	_, err = a.Request(addSpace, req)
+	if err == nil {
+		t.Fatalf("Failed to detect wrong request: preferred IP from different subnet")
+	}
+
+	// Preferred address specified and nil subnet
+	req = &AddressRequest{Address: net.ParseIP("172.17.0.23")}
+	_, err = a.Request(addSpace, req)
+	if err == nil {
+		t.Fatalf("Failed to detect wrong request: subnet not specified but preferred address specified")
+	}
+}
+
+func TestRequest(t *testing.T) {
+	// Request N addresses from different size subnets, verifying last request
+	// returns expected address. Internal subnet host size is Allocator's default, 16
+	input := []struct {
+		subnet string
+		numReq int
+		lastIP string
+	}{
+		{"192.168.59.0/24", 254, "192.168.59.254"},
+		{"192.168.240.0/20", 254, "192.168.240.254"},
+		{"192.168.0.0/16", 254, "192.168.0.254"},
+		{"10.16.0.0/16", 254, "10.16.0.254"},
+		{"10.128.0.0/12", 254, "10.128.0.254"},
+		{"10.0.0.0/8", 254, "10.0.0.254"},
+		{"192.168.0.0/16", 256, "192.168.1.2"},
+		{"10.0.0.0/8", 256, "10.0.1.2"},
+
+		{"192.168.128.0/18", 4 * 254, "192.168.131.254"},
+		{"192.168.240.0/20", 16 * 254, "192.168.255.254"},
+
+		{"192.168.0.0/16", 256 * 254, "192.168.255.254"},
+		{"10.0.0.0/8", 256 * 254, "10.0.255.254"},
+		{"10.0.0.0/8", 257 * 254, "10.1.0.254"},
+		//{"10.0.0.0/8", 100 * 256 * 254, "10.99.255.254"},
+	}
+
+	for _, d := range input {
+		assertNRequests(t, d.subnet, d.numReq, d.lastIP)
+	}
+}
+
+func TestRelease(t *testing.T) {
+	var (
+		err    error
+		req    *AddressRequest
+		subnet = "192.168.0.0/16"
+	)
+
+	_, sub, _ := net.ParseCIDR(subnet)
+	a := getAllocator(sub)
+	req = &AddressRequest{Subnet: *sub}
+	bm := a.addresses[isKey{"default", subnet}]
+
+	// Allocate all addresses
+	for err != ErrNoAvailableIPs {
+		_, err = a.Request("default", req)
+	}
+
+	toRelease := []struct {
+		address string
+	}{
+		{"192.168.0.1"},
+		{"192.168.0.2"},
+		{"192.168.0.3"},
+		{"192.168.0.4"},
+		{"192.168.0.5"},
+		{"192.168.0.6"},
+		{"192.168.0.7"},
+		{"192.168.0.8"},
+		{"192.168.0.9"},
+		{"192.168.0.10"},
+		{"192.168.0.30"},
+		{"192.168.0.31"},
+		{"192.168.1.32"},
+
+		{"192.168.0.254"},
+		{"192.168.1.1"},
+		{"192.168.1.2"},
+
+		{"192.168.1.3"},
+
+		{"192.168.255.253"},
+		{"192.168.255.254"},
+	}
+
+	// One by one, relase the address and request again. We should get the same IP
+	req = &AddressRequest{Subnet: *sub}
+	for i, inp := range toRelease {
+		address := net.ParseIP(inp.address)
+		a.Release("default", address)
+		if bm.freeAddresses != 1 {
+			t.Fatalf("Failed to update free address count after release. Expected %d, Found: %d", i+1, bm.freeAddresses)
+		}
+
+		rsp, err := a.Request("default", req)
+		if err != nil {
+			t.Fatalf("Failed to obtain the address: %s", err.Error())
+		}
+		if !address.Equal(rsp.Address) {
+			t.Fatalf("Failed to obtain the same address. Expected: %s, Got: %s", address, rsp.Address)
+		}
+	}
+}
+
+func assertInternalSubnet(t *testing.T, hostSize int, bigSubnet, firstSmall, lastSmall string) {
+	_, subnet, _ := net.ParseCIDR(bigSubnet)
+	list, _ := getInternalSubnets(subnet, hostSize)
+	count := 1
+	ones, bits := subnet.Mask.Size()
+	diff := bits - ones - hostSize
+	if diff > 0 {
+		count <<= uint(diff)
+	}
+
+	if len(list) != count {
+		t.Fatalf("Wrong small subnets number. Expected: %d, Got: %d", count, len(list))
+	}
+	if firstSmall != list[0].String() {
+		t.Fatalf("Wrong first small subent. Expected: %v, Got: %v", firstSmall, list[0])
+	}
+	if lastSmall != list[count-1].String() {
+		t.Fatalf("Wrong last small subent. Expected: %v, Got: %v", lastSmall, list[count-1])
+	}
+}
+
+func assertGetAddress(t *testing.T, subnet string) {
+	var (
+		err       error
+		printTime = false
+		a         = &Allocator{}
+	)
+
+	_, sub, _ := net.ParseCIDR(subnet)
+	ones, bits := sub.Mask.Size()
+	zeroes := bits - ones
+	numAddresses := 1 << uint(zeroes)
+
+	var expectedMax uint32
+	if numAddresses >= 32 {
+		expectedMax = uint32(1<<32 - 1)
+	} else {
+		expectedMax = (1<<uint(numAddresses) - 1) << uint(32-numAddresses)
+	}
+
+	bm := &bitmask{
+		subnet:        sub,
+		addressMask:   bitseq.New(uint32(numAddresses)),
+		freeAddresses: numAddresses,
+	}
+	numBlocks := bm.addressMask.Count
+
+	start := time.Now()
+	run := 0
+	for err != ErrNoAvailableIPs {
+		_, err = a.getAddress(bm, nil, v4)
+		run++
+	}
+	if printTime {
+		fmt.Printf("\nTaken %v, to allocate all addresses on %s. (nemAddresses: %d. Runs: %d)", time.Since(start), subnet, numAddresses, run)
+	}
+	if bm.addressMask.Block != expectedMax || bm.addressMask.Count != numBlocks {
+		t.Fatalf("Failed to effectively reserve all addresses on %s. Expected (0x%x, %d) as first sequence. Found (0x%x,%d)",
+			subnet, expectedMax, numBlocks, bm.addressMask.Block, bm.addressMask.Count)
+	}
+}
+
+func assertNRequests(t *testing.T, subnet string, numReq int, lastExpectedIP string) {
+	var (
+		err       error
+		req       *AddressRequest
+		rsp       *AddressResponse
+		printTime = false
+	)
+
+	_, sub, _ := net.ParseCIDR(subnet)
+	lastIP := net.ParseIP(lastExpectedIP)
+
+	a := getAllocator(sub)
+	req = &AddressRequest{Subnet: *sub}
+
+	i := 0
+	start := time.Now()
+	for ; i < numReq; i++ {
+		rsp, err = a.Request("default", req)
+	}
+	if printTime {
+		fmt.Printf("\nTaken %v, to allocate %d addresses on %s\n", time.Since(start), numReq, subnet)
+	}
+
+	if !lastIP.Equal(rsp.Address) {
+		t.Fatalf("Wrong last IP. Expected %s. Got: %s (err: %v, ind: %d)", lastExpectedIP, rsp.Address.String(), err, i)
+	}
+}
+
+func benchmarkRequest(subnet *net.IPNet) {
+	var err error
+
+	a := NewAllocator()
+	a.internalHostSize = 20
+	a.AddSubnet("default", &SubnetInfo{Subnet: subnet})
+
+	req := &AddressRequest{Subnet: *subnet}
+	for err != ErrNoAvailableIPs {
+		_, err = a.Request("default", req)
+
+	}
+}
+
+func benchMarkRequest(subnet *net.IPNet, b *testing.B) {
+	for n := 0; n < b.N; n++ {
+		benchmarkRequest(subnet)
+	}
+}
+
+func BenchmarkRequest_24(b *testing.B) {
+	benchmarkRequest(&net.IPNet{IP: []byte{10, 0, 0, 0}, Mask: []byte{255, 255, 255, 0}})
+}
+
+func BenchmarkRequest_16(b *testing.B) {
+	benchmarkRequest(&net.IPNet{IP: []byte{10, 0, 0, 0}, Mask: []byte{255, 255, 0, 0}})
+}
+
+func BenchmarkRequest_8(b *testing.B) {
+	benchmarkRequest(&net.IPNet{IP: []byte{10, 0, 0, 0}, Mask: []byte{255, 0xfc, 0, 0}})
+}