ipam/manager.go

// Copyright 2017 Microsoft. All rights reserved.
// MIT License

package ipam

import (
	"sync"
	"time"

	"github.com/Azure/azure-container-networking/common"
	"github.com/Azure/azure-container-networking/platform"
	"github.com/Azure/azure-container-networking/store"
	"go.uber.org/zap"
)

const (
	// IPAM store key.
	storeKey = "IPAM"
)

// AddressManager manages the set of address spaces and pools allocated to containers.
type addressManager struct {
	Version    string
	TimeStamp  time.Time
	AddrSpaces map[string]*addressSpace `json:"AddressSpaces"`
	store      store.KeyValueStore
	source     addressConfigSource
	netApi     common.NetApi
	sync.Mutex
}

// AddressManager API.
type AddressManager interface {
	Initialize(config *common.PluginConfig, rehydrateIpamInfoOnReboot bool, options map[string]interface{}) error
	Uninitialize()

	StartSource(options map[string]interface{}) error
	StopSource()

	GetDefaultAddressSpaces() (string, string)

	RequestPool(asId, poolId, subPoolId string, options map[string]string, v6 bool) (string, string, error)
	ReleasePool(asId, poolId string) error
	GetPoolInfo(asId, poolId string) (*AddressPoolInfo, error)

	RequestAddress(asId, poolId, address string, options map[string]string) (string, error)
	ReleaseAddress(asId, poolId, address string, options map[string]string) error
}

// AddressConfigSource configures the address pools managed by AddressManager.
type addressConfigSource interface {
	start(sink addressConfigSink) error
	stop()
	refresh() error
}

// AddressConfigSink interface is used by AddressConfigSources to configure address pools.
type addressConfigSink interface {
	newAddressSpace(id string, scope int) (*addressSpace, error)
	setAddressSpace(*addressSpace) error
}

// Creates a new address manager.
func NewAddressManager() (AddressManager, error) {
	am := &addressManager{
		AddrSpaces: make(map[string]*addressSpace),
	}

	return am, nil
}

// Initialize configures address manager.
func (am *addressManager) Initialize(config *common.PluginConfig, rehydrateIpamInfoOnReboot bool, options map[string]interface{}) error {
	am.Version = config.Version
	am.store = config.Store
	am.netApi = config.NetApi

	// Restore persisted state.
	err := am.restore(rehydrateIpamInfoOnReboot)
	if err != nil {
		return err
	}

	// Start source.
	err = am.StartSource(options)

	return err
}

// Uninitialize cleans up address manager.
func (am *addressManager) Uninitialize() {
	am.StopSource()
}

// Restore reads address manager state from persistent store.
func (am *addressManager) restore(rehydrateIpamInfoOnReboot bool) error {
	// Skip if a store is not provided.
	if am.store == nil {
		logger.Info("ipam store is nil")
		return nil
	}

	// Read any persisted state.
	err := am.store.Read(storeKey, am)
	if err != nil {
		if err == store.ErrKeyNotFound {
			logger.Info("store key not found")
			return nil
		} else if err == store.ErrStoreEmpty {
			logger.Info("store empty")
			return nil
		} else {
			logger.Error("Failed to restore state", zap.Error(err))
			return err
		}
	}

	// Populate pointers.
	for _, as := range am.AddrSpaces {
		for _, ap := range as.Pools {
			ap.as = as
			ap.addrsByID = make(map[string]*addressRecord)

			for _, ar := range ap.Addresses {
				if ar.ID != "" {
					ap.addrsByID[ar.ID] = ar
				}
			}
		}
	}

	// if rebooted mark the ip as not in use.
	if rehydrateIpamInfoOnReboot {
		// Check if the VM is rebooted.
		modTime, err := am.store.GetModificationTime()
		if err == nil {
			p := platform.NewExecClient(nil)
			rebootTime, err := p.GetLastRebootTime()
			logger.Info("reboot store mod", zap.Any("rebootTime", rebootTime), zap.Any("modTime", modTime))

			if err == nil && rebootTime.After(modTime) {
				logger.Info("Rehydrating ipam state from persistent store")
				for _, as := range am.AddrSpaces {
					for _, ap := range as.Pools {
						ap.as = as
						ap.RefCount = 0

						for _, ar := range ap.Addresses {
							ar.InUse = false
						}
					}
				}
			}
		}
	}

	logger.Info("Restored state", zap.Any("am", am))

	return nil
}

// Save writes address manager state to persistent store.
func (am *addressManager) save() error {
	// Skip if a store is not provided.
	if am.store == nil {
		logger.Info("ipam store is nil")
		return nil
	}

	// Update time stamp.
	am.TimeStamp = time.Now()

	logger.Info("saving ipam state")
	err := am.store.Write(storeKey, am)
	if err == nil {
		logger.Info("Save succeeded")
	} else {
		logger.Error("Save failed", zap.Error(err))
	}
	return err
}

// Starts configuration source.
func (am *addressManager) StartSource(options map[string]interface{}) error {
	var err error
	var isLoaded bool
	environment, _ := options[common.OptEnvironment].(string)

	if am.AddrSpaces != nil && len(am.AddrSpaces) > 0 &&
		am.AddrSpaces[LocalDefaultAddressSpaceId] != nil &&
		len(am.AddrSpaces[LocalDefaultAddressSpaceId].Pools) > 0 {
		isLoaded = true
	}

	switch environment {
	case common.OptEnvironmentAzure:
		am.source, err = newAzureSource(options)

	case common.OptEnvironmentMAS:
		am.source, err = newFileIpamSource(options)

	case common.OptEnvironmentFileIpam:
		am.source, err = newFileIpamSource(options)

	case common.OptEnvironmentIPv6NodeIpam:
		am.source, err = newIPv6IpamSource(options, isLoaded)

	case "null":
		am.source, err = newNullSource()

	case "":
		am.source = nil

	default:
		return errInvalidConfiguration
	}

	if am.source != nil {
		logger.Info("Starting source", zap.String("environment", environment))
		err = am.source.start(am)
	}

	if err != nil {
		logger.Error("Failed to start source", zap.String("environment", environment), zap.Error(err))
	}

	return err
}

// Stops the configuration source.
func (am *addressManager) StopSource() {
	if am.source != nil {
		am.source.stop()
		am.source = nil
	}
}

// Signals configuration source to refresh.
func (am *addressManager) refreshSource() {
	if am.source != nil {
		logger.Info("Refreshing address source.")
		err := am.source.refresh()
		if err != nil {
			logger.Error("Source refresh failed", zap.Error(err))
		}
	}
}

//
// AddressManager API
//
// Provides atomic stateful wrappers around core IPAM functionality.
//

// GetDefaultAddressSpaces returns the default local and global address space IDs.
func (am *addressManager) GetDefaultAddressSpaces() (string, string) {
	var localId, globalId string

	am.Lock()
	defer am.Unlock()

	am.refreshSource()

	local := am.AddrSpaces[LocalDefaultAddressSpaceId]
	if local != nil {
		localId = local.Id
	}

	global := am.AddrSpaces[GlobalDefaultAddressSpaceId]
	if global != nil {
		globalId = global.Id
	}

	return localId, globalId
}

// RequestPool reserves an address pool.
func (am *addressManager) RequestPool(asId, poolId, subPoolId string, options map[string]string, v6 bool) (string, string, error) {
	am.Lock()
	defer am.Unlock()

	am.refreshSource()

	as, err := am.getAddressSpace(asId)
	if err != nil {
		return "", "", err
	}

	pool, err := as.requestPool(poolId, subPoolId, options, v6)
	if err != nil {
		return "", "", err
	}

	err = am.save()
	if err != nil {
		return "", "", err
	}

	return pool.Id, pool.Subnet.String(), nil
}

// ReleasePool releases a previously reserved address pool.
func (am *addressManager) ReleasePool(asId string, poolId string) error {
	am.Lock()
	defer am.Unlock()

	am.refreshSource()

	as, err := am.getAddressSpace(asId)
	if err != nil {
		return err
	}

	err = as.releasePool(poolId)
	if err != nil {
		return err
	}

	err = am.save()
	if err != nil {
		return err
	}

	return nil
}

// GetPoolInfo returns information about the given address pool.
func (am *addressManager) GetPoolInfo(asId string, poolId string) (*AddressPoolInfo, error) {
	am.Lock()
	defer am.Unlock()

	as, err := am.getAddressSpace(asId)
	if err != nil {
		return nil, err
	}

	ap, err := as.getAddressPool(poolId)
	if err != nil {
		return nil, err
	}

	return ap.getInfo(), nil
}

// RequestAddress reserves a new address from the address pool.
func (am *addressManager) RequestAddress(asId, poolId, address string, options map[string]string) (string, error) {
	am.Lock()
	defer am.Unlock()

	am.refreshSource()

	as, err := am.getAddressSpace(asId)
	if err != nil {
		return "", err
	}

	ap, err := as.getAddressPool(poolId)
	if err != nil {
		return "", err
	}

	addr, err := ap.requestAddress(address, options)
	if err != nil {
		return "", err
	}

	err = am.save()
	if err != nil {
		ap.releaseAddress(addr, options)
		return "", err
	}

	return addr, nil
}

// ReleaseAddress releases a previously reserved address.
func (am *addressManager) ReleaseAddress(asId string, poolId string, address string, options map[string]string) error {
	am.Lock()
	defer am.Unlock()

	am.refreshSource()

	as, err := am.getAddressSpace(asId)
	if err != nil {
		return err
	}

	ap, err := as.getAddressPool(poolId)
	if err != nil {
		return err
	}

	err = ap.releaseAddress(address, options)
	if err != nil {
		return err
	}

	err = am.save()
	if err != nil {
		return err
	}

	return nil
}