package netpol

import (
	"crypto/sha256"
	"encoding/base32"
	"errors"
	"fmt"
	"net"
	"regexp"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/cloudnativelabs/kube-router/pkg/healthcheck"
	"github.com/cloudnativelabs/kube-router/pkg/metrics"
	"github.com/cloudnativelabs/kube-router/pkg/options"
	"github.com/cloudnativelabs/kube-router/pkg/utils"
	"github.com/coreos/go-iptables/iptables"
	"github.com/golang/glog"
	"github.com/prometheus/client_golang/prometheus"

	api "k8s.io/api/core/v1"
	apiextensions "k8s.io/api/extensions/v1beta1"
	networking "k8s.io/api/networking/v1"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/client-go/kubernetes"
	listers "k8s.io/client-go/listers/core/v1"
	"k8s.io/client-go/tools/cache"
)

const (
	networkPolicyAnnotation      = "net.beta.kubernetes.io/network-policy"
	kubePodFirewallChainPrefix   = "KUBE-POD-FW-"
	kubeNetworkPolicyChainPrefix = "KUBE-NWPLCY-"
	kubeSourceIpSetPrefix        = "KUBE-SRC-"
	kubeDestinationIpSetPrefix   = "KUBE-DST-"
)

// Network policy controller provides both ingress and egress filtering for the pods as per the defined network
// policies. Two different types of iptables chains are used. Each pod running on the node which either
// requires ingress or egress filtering gets a pod specific chains. Each network policy has a iptable chain, which
// has rules expressed through ipsets matching source and destination pod ip's. In the FORWARD chain of the
// filter table a rule is added to jump the traffic originating (in case of egress network policy) from the pod
// or destined (in case of ingress network policy) to the pod specific iptable chain. Each
// pod specific iptable chain has rules to jump to the network polices chains, that pod matches. So packet
// originating/destined from/to pod goes through fitler table's, FORWARD chain, followed by pod specific chain,
// followed by one or more network policy chains, till there is a match which will accept the packet, or gets
// dropped by the rule in the pod chain, if there is no match.

// NetworkPolicyController strcut to hold information required by NetworkPolicyController
type NetworkPolicyController struct {
	nodeIP          net.IP
	nodeHostName    string
	mu              sync.Mutex
	syncPeriod      time.Duration
	MetricsEnabled  bool
	v1NetworkPolicy bool
	readyForUpdates bool

	// list of all active network policies expressed as networkPolicyInfo
	networkPoliciesInfo *[]networkPolicyInfo
	ipSetHandler        *utils.IPSet

	podLister cache.Indexer
	npLister  cache.Indexer
	nsLister  cache.Indexer

	PodEventHandler           cache.ResourceEventHandler
	NamespaceEventHandler     cache.ResourceEventHandler
	NetworkPolicyEventHandler cache.ResourceEventHandler
}

// internal structure to represent a network policy
type networkPolicyInfo struct {
	name      string
	namespace string
	labels    map[string]string

	// set of pods matching network policy spec podselector label selector
	targetPods map[string]podInfo

	// whitelist ingress rules from the network policy spec
	ingressRules []ingressRule

	// whitelist egress rules from the network policy spec
	egressRules []egressRule

	// policy type "ingress" or "egress" or "both" as defined by PolicyType in the spec
	policyType string
}

// internal structure to represent Pod
type podInfo struct {
	ip        string
	name      string
	namespace string
	labels    map[string]string
}

// internal stucture to represent NetworkPolicyIngressRule in the spec
type ingressRule struct {
	matchAllPorts  bool
	ports          []protocolAndPort
	matchAllSource bool
	srcPods        []podInfo
	srcIPBlocks    [][]string
}

// internal structure to represent NetworkPolicyEgressRule in the spec
type egressRule struct {
	matchAllPorts        bool
	ports                []protocolAndPort
	matchAllDestinations bool
	dstPods              []podInfo
	dstIPBlocks          [][]string
}

type protocolAndPort struct {
	protocol string
	port     string
}

// Run runs forver till we receive notification on stopCh
func (npc *NetworkPolicyController) Run(healthChan chan<- *healthcheck.ControllerHeartbeat, stopCh <-chan struct{}, wg *sync.WaitGroup) {
	t := time.NewTicker(npc.syncPeriod)
	defer t.Stop()
	defer wg.Done()

	glog.Info("Starting network policy controller")

	// loop forever till notified to stop on stopCh
	for {
		select {
		case <-stopCh:
			glog.Info("Shutting down network policies controller")
			return
		default:
		}

		glog.V(1).Info("Performing periodic sync of iptables to reflect network policies")
		err := npc.Sync()
		if err != nil {
			glog.Errorf("Error during periodic sync of network policies in network policy controller. Error: " + err.Error())
			glog.Errorf("Skipping sending heartbeat from network policy controller as periodic sync failed.")
		} else {
			healthcheck.SendHeartBeat(healthChan, "NPC")
		}
		npc.readyForUpdates = true
		select {
		case <-stopCh:
			glog.Infof("Shutting down network policies controller")
			return
		case <-t.C:
		}
	}
}

// OnPodUpdate handles updates to pods from the Kubernetes api server
func (npc *NetworkPolicyController) OnPodUpdate(obj interface{}) {
	pod := obj.(*api.Pod)
	glog.V(2).Infof("Received update to pod: %s/%s", pod.Namespace, pod.Name)

	if !npc.readyForUpdates {
		glog.V(3).Infof("Skipping update to pod: %s/%s, controller still performing bootup full-sync", pod.Namespace, pod.Name)
		return
	}

	err := npc.Sync()
	if err != nil {
		glog.Errorf("Error syncing network policy for the update to pod: %s/%s Error: %s", pod.Namespace, pod.Name, err)
	}
}

// OnNetworkPolicyUpdate handles updates to network policy from the kubernetes api server
func (npc *NetworkPolicyController) OnNetworkPolicyUpdate(obj interface{}) {
	netpol := obj.(*networking.NetworkPolicy)
	glog.V(2).Infof("Received update for network policy: %s/%s", netpol.Namespace, netpol.Name)

	if !npc.readyForUpdates {
		glog.V(3).Infof("Skipping update to network policy: %s/%s, controller still performing bootup full-sync", netpol.Namespace, netpol.Name)
		return
	}

	err := npc.Sync()
	if err != nil {
		glog.Errorf("Error syncing network policy for the update to network policy: %s/%s Error: %s", netpol.Namespace, netpol.Name, err)
	}
}

// OnNamespaceUpdate handles updates to namespace from kubernetes api server
func (npc *NetworkPolicyController) OnNamespaceUpdate(obj interface{}) {
	namespace := obj.(*api.Namespace)
	// namespace (and annotations on it) has no significance in GA ver of network policy
	if npc.v1NetworkPolicy {
		return
	}
	glog.V(2).Infof("Received update for namespace: %s", namespace.Name)

	err := npc.Sync()
	if err != nil {
		glog.Errorf("Error syncing on namespace update: %s", err)
	}
}

// Sync synchronizes iptables to desired state of network policies
func (npc *NetworkPolicyController) Sync() error {

	var err error
	npc.mu.Lock()
	defer npc.mu.Unlock()

	start := time.Now()
	syncVersion := strconv.FormatInt(start.UnixNano(), 10)
	defer func() {
		endTime := time.Since(start)
		if npc.MetricsEnabled {
			metrics.ControllerIptablesSyncTime.Observe(endTime.Seconds())
		}
		glog.V(1).Infof("sync iptables took %v", endTime)
	}()

	glog.V(1).Infof("Starting sync of iptables with version: %s", syncVersion)
	if npc.v1NetworkPolicy {
		npc.networkPoliciesInfo, err = npc.buildNetworkPoliciesInfo()
		if err != nil {
			return errors.New("Aborting sync. Failed to build network policies: " + err.Error())
		}
	} else {
		// TODO remove the Beta support
		npc.networkPoliciesInfo, err = npc.buildBetaNetworkPoliciesInfo()
		if err != nil {
			return errors.New("Aborting sync. Failed to build network policies: " + err.Error())
		}
	}

	activePolicyChains, activePolicyIpSets, err := npc.syncNetworkPolicyChains(syncVersion)
	if err != nil {
		return errors.New("Aborting sync. Failed to sync network policy chains: " + err.Error())
	}

	activePodFwChains, err := npc.syncPodFirewallChains(syncVersion)
	if err != nil {
		return errors.New("Aborting sync. Failed to sync pod firewalls: " + err.Error())
	}

	err = cleanupStaleRules(activePolicyChains, activePodFwChains, activePolicyIpSets)
	if err != nil {
		return errors.New("Aborting sync. Failed to cleanup stale iptable rules: " + err.Error())
	}

	return nil
}

// Configure iptable rules representing each network policy. All pod's matched by
// network policy spec podselector labels are grouped together in one ipset which
// is used for matching destination ip address. Each ingress rule in the network
// policyspec is evaluated to set of matching pods, which are grouped in to a
// ipset used for source ip addr matching.
func (npc *NetworkPolicyController) syncNetworkPolicyChains(version string) (map[string]bool, map[string]bool, error) {
	start := time.Now()
	defer func() {
		endTime := time.Since(start)
		metrics.ControllerPolicyChainsSyncTime.Observe(endTime.Seconds())
		glog.V(2).Infof("Syncing network policy chains took %v", endTime)
	}()
	activePolicyChains := make(map[string]bool)
	activePolicyIpSets := make(map[string]bool)

	iptablesCmdHandler, err := iptables.New()
	if err != nil {
		glog.Fatalf("Failed to initialize iptables executor due to: %s", err.Error())
	}

	// run through all network policies
	for _, policy := range *npc.networkPoliciesInfo {

		// ensure there is a unique chain per network policy in filter table
		policyChainName := networkPolicyChainName(policy.namespace, policy.name, version)
		err := iptablesCmdHandler.NewChain("filter", policyChainName)
		if err != nil && err.(*iptables.Error).ExitStatus() != 1 {
			return nil, nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}

		activePolicyChains[policyChainName] = true

		// create a ipset for all destination pod ip's matched by the policy spec PodSelector
		targetDestPodIpSetName := policyDestinationPodIpSetName(policy.namespace, policy.name)
		targetDestPodIpSet, err := npc.ipSetHandler.Create(targetDestPodIpSetName, utils.TypeHashIP, utils.OptionTimeout, "0")
		if err != nil {
			return nil, nil, fmt.Errorf("failed to create ipset: %s", err.Error())
		}

		// create a ipset for all source pod ip's matched by the policy spec PodSelector
		targetSourcePodIpSetName := policySourcePodIpSetName(policy.namespace, policy.name)
		targetSourcePodIpSet, err := npc.ipSetHandler.Create(targetSourcePodIpSetName, utils.TypeHashIP, utils.OptionTimeout, "0")
		if err != nil {
			return nil, nil, fmt.Errorf("failed to create ipset: %s", err.Error())
		}

		activePolicyIpSets[targetDestPodIpSet.Name] = true
		activePolicyIpSets[targetSourcePodIpSet.Name] = true

		currnetPodIps := make([]string, 0, len(policy.targetPods))
		for ip := range policy.targetPods {
			currnetPodIps = append(currnetPodIps, ip)
		}

		err = targetSourcePodIpSet.Refresh(currnetPodIps, utils.OptionTimeout, "0")
		if err != nil {
			glog.Errorf("failed to refresh targetSourcePodIpSet: " + err.Error())
		}
		err = targetDestPodIpSet.Refresh(currnetPodIps, utils.OptionTimeout, "0")
		if err != nil {
			glog.Errorf("failed to refresh targetDestPodIpSet: " + err.Error())
		}

		err = npc.processIngressRules(policy, targetDestPodIpSetName, activePolicyIpSets, version)
		if err != nil {
			return nil, nil, err
		}

		err = npc.processEgressRules(policy, targetSourcePodIpSetName, activePolicyIpSets, version)
		if err != nil {
			return nil, nil, err
		}
	}

	glog.V(2).Infof("Iptables chains in the filter table are synchronized with the network policies.")

	return activePolicyChains, activePolicyIpSets, nil
}

func (npc *NetworkPolicyController) processIngressRules(policy networkPolicyInfo,
	targetDestPodIpSetName string, activePolicyIpSets map[string]bool, version string) error {

	// From network policy spec: "If field 'Ingress' is empty then this NetworkPolicy does not allow any traffic "
	// so no whitelist rules to be added to the network policy
	if policy.ingressRules == nil {
		return nil
	}

	iptablesCmdHandler, err := iptables.New()
	if err != nil {
		return fmt.Errorf("Failed to initialize iptables executor due to: %s", err.Error())
	}

	policyChainName := networkPolicyChainName(policy.namespace, policy.name, version)

	// run through all the ingress rules in the spec and create iptable rules
	// in the chain for the network policy
	for i, ingressRule := range policy.ingressRules {

		if len(ingressRule.srcPods) != 0 {
			srcPodIpSetName := policyIndexedSourcePodIpSetName(policy.namespace, policy.name, i)
			srcPodIpSet, err := npc.ipSetHandler.Create(srcPodIpSetName, utils.TypeHashIP, utils.OptionTimeout, "0")
			if err != nil {
				return fmt.Errorf("failed to create ipset: %s", err.Error())
			}

			activePolicyIpSets[srcPodIpSet.Name] = true

			ingressRuleSrcPodIps := make([]string, 0, len(ingressRule.srcPods))
			for _, pod := range ingressRule.srcPods {
				ingressRuleSrcPodIps = append(ingressRuleSrcPodIps, pod.ip)
			}
			err = srcPodIpSet.Refresh(ingressRuleSrcPodIps, utils.OptionTimeout, "0")
			if err != nil {
				glog.Errorf("failed to refresh srcPodIpSet: " + err.Error())
			}

			if len(ingressRule.ports) != 0 {
				// case where 'ports' details and 'from' details specified in the ingress rule
				// so match on specified source and destination ip's and specified port and protocol
				for _, portProtocol := range ingressRule.ports {
					comment := "rule to ACCEPT traffic from source pods to dest pods selected by policy name " +
						policy.name + " namespace " + policy.namespace
					args := []string{"-m", "comment", "--comment", comment,
						"-m", "set", "--set", srcPodIpSetName, "src",
						"-m", "set", "--set", targetDestPodIpSetName, "dst",
						"-p", portProtocol.protocol,
						"--dport", portProtocol.port,
						"-j", "ACCEPT"}
					err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
					if err != nil {
						return fmt.Errorf("Failed to run iptables command: %s", err.Error())
					}
				}
			} else {
				// case where no 'ports' details specified in the ingress rule but 'from' details specified
				// so match on specified source and destination ip with all port and protocol
				comment := "rule to ACCEPT traffic from source pods to dest pods selected by policy name " +
					policy.name + " namespace " + policy.namespace
				args := []string{"-m", "comment", "--comment", comment,
					"-m", "set", "--set", srcPodIpSetName, "src",
					"-m", "set", "--set", targetDestPodIpSetName, "dst",
					"-j", "ACCEPT"}
				err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
				if err != nil {
					return fmt.Errorf("Failed to run iptables command: %s", err.Error())
				}
			}
		}

		// case where only 'ports' details specified but no 'from' details in the ingress rule
		// so match on all sources, with specified port and protocol
		if ingressRule.matchAllSource && !ingressRule.matchAllPorts {
			for _, portProtocol := range ingressRule.ports {
				comment := "rule to ACCEPT traffic from all sources to dest pods selected by policy name: " +
					policy.name + " namespace " + policy.namespace
				args := []string{"-m", "comment", "--comment", comment,
					"-m", "set", "--set", targetDestPodIpSetName, "dst",
					"-p", portProtocol.protocol,
					"--dport", portProtocol.port,
					"-j", "ACCEPT"}
				err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
				if err != nil {
					return fmt.Errorf("Failed to run iptables command: %s", err.Error())
				}
			}
		}

		// case where nether ports nor from details are speified in the ingress rule
		// so match on all ports, protocol, source IP's
		if ingressRule.matchAllSource && ingressRule.matchAllPorts {
			comment := "rule to ACCEPT traffic from all sources to dest pods selected by policy name: " +
				policy.name + " namespace " + policy.namespace
			args := []string{"-m", "comment", "--comment", comment,
				"-m", "set", "--set", targetDestPodIpSetName, "dst",
				"-j", "ACCEPT"}
			err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
			if err != nil {
				return fmt.Errorf("Failed to run iptables command: %s", err.Error())
			}
		}

		if len(ingressRule.srcIPBlocks) != 0 {
			srcIpBlockIpSetName := policyIndexedSourceIpBlockIpSetName(policy.namespace, policy.name, i)
			srcIpBlockIpSet, err := npc.ipSetHandler.Create(srcIpBlockIpSetName, utils.TypeHashNet, utils.OptionTimeout, "0")
			if err != nil {
				return fmt.Errorf("failed to create ipset: %s", err.Error())
			}
			activePolicyIpSets[srcIpBlockIpSet.Name] = true
			err = srcIpBlockIpSet.RefreshWithBuiltinOptions(ingressRule.srcIPBlocks)
			if err != nil {
				glog.Errorf("failed to refresh srcIpBlockIpSet: " + err.Error())
			}
			if !ingressRule.matchAllPorts {
				for _, portProtocol := range ingressRule.ports {
					comment := "rule to ACCEPT traffic from specified ipBlocks to dest pods selected by policy name: " +
						policy.name + " namespace " + policy.namespace
					args := []string{"-m", "comment", "--comment", comment,
						"-m", "set", "--set", srcIpBlockIpSetName, "src",
						"-m", "set", "--set", targetDestPodIpSetName, "dst",
						"-p", portProtocol.protocol,
						"--dport", portProtocol.port,
						"-j", "ACCEPT"}
					err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
					if err != nil {
						return fmt.Errorf("Failed to run iptables command: %s", err.Error())
					}
				}
			}
			if ingressRule.matchAllPorts {
				comment := "rule to ACCEPT traffic from specified ipBlocks to dest pods selected by policy name: " +
					policy.name + " namespace " + policy.namespace
				args := []string{"-m", "comment", "--comment", comment,
					"-m", "set", "--set", srcIpBlockIpSetName, "src",
					"-m", "set", "--set", targetDestPodIpSetName, "dst",
					"-j", "ACCEPT"}
				err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
				if err != nil {
					return fmt.Errorf("Failed to run iptables command: %s", err.Error())
				}
			}
		}
	}

	return nil
}

func (npc *NetworkPolicyController) processEgressRules(policy networkPolicyInfo,
	targetSourcePodIpSetName string, activePolicyIpSets map[string]bool, version string) error {

	// From network policy spec: "If field 'Ingress' is empty then this NetworkPolicy does not allow any traffic "
	// so no whitelist rules to be added to the network policy
	if policy.egressRules == nil {
		return nil
	}

	iptablesCmdHandler, err := iptables.New()
	if err != nil {
		return fmt.Errorf("Failed to initialize iptables executor due to: %s", err.Error())
	}

	policyChainName := networkPolicyChainName(policy.namespace, policy.name, version)

	// run through all the egress rules in the spec and create iptable rules
	// in the chain for the network policy
	for i, egressRule := range policy.egressRules {

		if len(egressRule.dstPods) != 0 {
			dstPodIpSetName := policyIndexedDestinationPodIpSetName(policy.namespace, policy.name, i)
			dstPodIpSet, err := npc.ipSetHandler.Create(dstPodIpSetName, utils.TypeHashIP, utils.OptionTimeout, "0")
			if err != nil {
				return fmt.Errorf("failed to create ipset: %s", err.Error())
			}

			activePolicyIpSets[dstPodIpSet.Name] = true

			egressRuleDstPodIps := make([]string, 0, len(egressRule.dstPods))
			for _, pod := range egressRule.dstPods {
				egressRuleDstPodIps = append(egressRuleDstPodIps, pod.ip)
			}
			dstPodIpSet.Refresh(egressRuleDstPodIps, utils.OptionTimeout, "0")

			if len(egressRule.ports) != 0 {
				// case where 'ports' details and 'from' details specified in the egress rule
				// so match on specified source and destination ip's and specified port and protocol
				for _, portProtocol := range egressRule.ports {
					comment := "rule to ACCEPT traffic from source pods to dest pods selected by policy name " +
						policy.name + " namespace " + policy.namespace
					args := []string{"-m", "comment", "--comment", comment,
						"-m", "set", "--set", targetSourcePodIpSetName, "src",
						"-m", "set", "--set", dstPodIpSetName, "dst",
						"-p", portProtocol.protocol,
						"--dport", portProtocol.port,
						"-j", "ACCEPT"}
					err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
					if err != nil {
						return fmt.Errorf("Failed to run iptables command: %s", err.Error())
					}
				}
			} else {
				// case where no 'ports' details specified in the ingress rule but 'from' details specified
				// so match on specified source and destination ip with all port and protocol
				comment := "rule to ACCEPT traffic from source pods to dest pods selected by policy name " +
					policy.name + " namespace " + policy.namespace
				args := []string{"-m", "comment", "--comment", comment,
					"-m", "set", "--set", targetSourcePodIpSetName, "src",
					"-m", "set", "--set", dstPodIpSetName, "dst",
					"-j", "ACCEPT"}
				err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
				if err != nil {
					return fmt.Errorf("Failed to run iptables command: %s", err.Error())
				}
			}
		}

		// case where only 'ports' details specified but no 'to' details in the egress rule
		// so match on all sources, with specified port and protocol
		if egressRule.matchAllDestinations && !egressRule.matchAllPorts {
			for _, portProtocol := range egressRule.ports {
				comment := "rule to ACCEPT traffic from source pods to all destinations selected by policy name: " +
					policy.name + " namespace " + policy.namespace
				args := []string{"-m", "comment", "--comment", comment,
					"-m", "set", "--set", targetSourcePodIpSetName, "src",
					"-p", portProtocol.protocol,
					"--dport", portProtocol.port,
					"-j", "ACCEPT"}
				err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
				if err != nil {
					return fmt.Errorf("Failed to run iptables command: %s", err.Error())
				}
			}
		}

		// case where nether ports nor from details are speified in the egress rule
		// so match on all ports, protocol, source IP's
		if egressRule.matchAllDestinations && egressRule.matchAllPorts {
			comment := "rule to ACCEPT traffic from source pods to all destinations selected by policy name: " +
				policy.name + " namespace " + policy.namespace
			args := []string{"-m", "comment", "--comment", comment,
				"-m", "set", "--set", targetSourcePodIpSetName, "src",
				"-j", "ACCEPT"}
			err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
			if err != nil {
				return fmt.Errorf("Failed to run iptables command: %s", err.Error())
			}
		}
		if len(egressRule.dstIPBlocks) != 0 {
			dstIpBlockIpSetName := policyIndexedDestinationIpBlockIpSetName(policy.namespace, policy.name, i)
			dstIpBlockIpSet, err := npc.ipSetHandler.Create(dstIpBlockIpSetName, utils.TypeHashNet, utils.OptionTimeout, "0")
			if err != nil {
				return fmt.Errorf("failed to create ipset: %s", err.Error())
			}
			activePolicyIpSets[dstIpBlockIpSet.Name] = true
			err = dstIpBlockIpSet.RefreshWithBuiltinOptions(egressRule.dstIPBlocks)
			if err != nil {
				glog.Errorf("failed to refresh dstIpBlockIpSet: " + err.Error())
			}
			if !egressRule.matchAllPorts {
				for _, portProtocol := range egressRule.ports {
					comment := "rule to ACCEPT traffic from source pods to specified ipBlocks selected by policy name: " +
						policy.name + " namespace " + policy.namespace
					args := []string{"-m", "comment", "--comment", comment,
						"-m", "set", "--set", targetSourcePodIpSetName, "src",
						"-m", "set", "--set", dstIpBlockIpSetName, "dst",
						"-p", portProtocol.protocol,
						"--dport", portProtocol.port,
						"-j", "ACCEPT"}
					err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
					if err != nil {
						return fmt.Errorf("Failed to run iptables command: %s", err.Error())
					}
				}
			}
			if egressRule.matchAllPorts {
				comment := "rule to ACCEPT traffic from source pods to specified ipBlocks selected by policy name: " +
					policy.name + " namespace " + policy.namespace
				args := []string{"-m", "comment", "--comment", comment,
					"-m", "set", "--set", targetSourcePodIpSetName, "src",
					"-m", "set", "--set", dstIpBlockIpSetName, "dst",
					"-j", "ACCEPT"}
				err := iptablesCmdHandler.AppendUnique("filter", policyChainName, args...)
				if err != nil {
					return fmt.Errorf("Failed to run iptables command: %s", err.Error())
				}
			}
		}
	}
	return nil
}

func (npc *NetworkPolicyController) syncPodFirewallChains(version string) (map[string]bool, error) {

	activePodFwChains := make(map[string]bool)

	iptablesCmdHandler, err := iptables.New()
	if err != nil {
		glog.Fatalf("Failed to initialize iptables executor: %s", err.Error())
	}

	// loop through the pods running on the node which to which ingress network policies to be applied
	ingressNetworkPolicyEnabledPods, err := npc.getIngressNetworkPolicyEnabledPods(npc.nodeIP.String())
	if err != nil {
		return nil, err
	}
	for _, pod := range *ingressNetworkPolicyEnabledPods {

		// below condition occurs when we get trasient update while removing or adding pod
		// subseqent update will do the correct action
		if len(pod.ip) == 0 || pod.ip == "" {
			continue
		}

		// ensure pod specific firewall chain exist for all the pods that need ingress firewall
		podFwChainName := podFirewallChainName(pod.namespace, pod.name, version)
		err = iptablesCmdHandler.NewChain("filter", podFwChainName)
		if err != nil && err.(*iptables.Error).ExitStatus() != 1 {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}
		activePodFwChains[podFwChainName] = true

		// add entries in pod firewall to run through required network policies
		for _, policy := range *npc.networkPoliciesInfo {
			if _, ok := policy.targetPods[pod.ip]; ok {
				comment := "run through nw policy " + policy.name
				policyChainName := networkPolicyChainName(policy.namespace, policy.name, version)
				args := []string{"-m", "comment", "--comment", comment, "-j", policyChainName}
				exists, err := iptablesCmdHandler.Exists("filter", podFwChainName, args...)
				if err != nil {
					return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
				}
				if !exists {
					err := iptablesCmdHandler.Insert("filter", podFwChainName, 1, args...)
					if err != nil && err.(*iptables.Error).ExitStatus() != 1 {
						return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
					}
				}
			}
		}

		comment := "rule to permit the traffic traffic to pods when source is the pod's local node"
		args := []string{"-m", "comment", "--comment", comment, "-m", "addrtype", "--src-type", "LOCAL", "-d", pod.ip, "-j", "ACCEPT"}
		exists, err := iptablesCmdHandler.Exists("filter", podFwChainName, args...)
		if err != nil {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}
		if !exists {
			err := iptablesCmdHandler.Insert("filter", podFwChainName, 1, args...)
			if err != nil {
				return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
			}
		}

		// ensure there is rule in filter table and FORWARD chain to jump to pod specific firewall chain
		// this rule applies to the traffic getting routed (coming for other node pods)
		comment = "rule to jump traffic destined to POD name:" + pod.name + " namespace: " + pod.namespace +
			" to chain " + podFwChainName
		args = []string{"-m", "comment", "--comment", comment, "-d", pod.ip, "-j", podFwChainName}
		exists, err = iptablesCmdHandler.Exists("filter", "FORWARD", args...)
		if err != nil {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}
		if !exists {
			err := iptablesCmdHandler.Insert("filter", "FORWARD", 1, args...)
			if err != nil {
				return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
			}
		}

		// ensure there is rule in filter table and OUTPUT chain to jump to pod specific firewall chain
		// this rule applies to the traffic from a pod getting routed back to another pod on same node by service proxy
		exists, err = iptablesCmdHandler.Exists("filter", "OUTPUT", args...)
		if err != nil {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}
		if !exists {
			err := iptablesCmdHandler.Insert("filter", "OUTPUT", 1, args...)
			if err != nil {
				return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
			}
		}

		// ensure there is rule in filter table and forward chain to jump to pod specific firewall chain
		// this rule applies to the traffic getting switched (coming for same node pods)
		comment = "rule to jump traffic destined to POD name:" + pod.name + " namespace: " + pod.namespace +
			" to chain " + podFwChainName
		args = []string{"-m", "physdev", "--physdev-is-bridged",
			"-m", "comment", "--comment", comment,
			"-d", pod.ip,
			"-j", podFwChainName}
		exists, err = iptablesCmdHandler.Exists("filter", "FORWARD", args...)
		if err != nil {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}
		if !exists {
			err = iptablesCmdHandler.Insert("filter", "FORWARD", 1, args...)
			if err != nil {
				return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
			}
		}

		// add default DROP rule at the end of chain
		comment = "default rule to REJECT traffic destined for POD name:" + pod.name + " namespace: " + pod.namespace
		args = []string{"-m", "comment", "--comment", comment, "-j", "REJECT"}
		err = iptablesCmdHandler.AppendUnique("filter", podFwChainName, args...)
		if err != nil {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}

		// ensure statefull firewall, that permits return traffic for the traffic originated by the pod
		comment = "rule for stateful firewall for pod"
		args = []string{"-m", "comment", "--comment", comment, "-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED", "-j", "ACCEPT"}
		exists, err = iptablesCmdHandler.Exists("filter", podFwChainName, args...)
		if err != nil {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}
		if !exists {
			err := iptablesCmdHandler.Insert("filter", podFwChainName, 1, args...)
			if err != nil {
				return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
			}
		}
	}

	// loop through the pods running on the node which egress network policies to be applied
	egressNetworkPolicyEnabledPods, err := npc.getEgressNetworkPolicyEnabledPods(npc.nodeIP.String())
	if err != nil {
		return nil, err
	}
	for _, pod := range *egressNetworkPolicyEnabledPods {

		// below condition occurs when we get trasient update while removing or adding pod
		// subseqent update will do the correct action
		if len(pod.ip) == 0 || pod.ip == "" {
			continue
		}

		// ensure pod specific firewall chain exist for all the pods that need egress firewall
		podFwChainName := podFirewallChainName(pod.namespace, pod.name, version)
		err = iptablesCmdHandler.NewChain("filter", podFwChainName)
		if err != nil && err.(*iptables.Error).ExitStatus() != 1 {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}
		activePodFwChains[podFwChainName] = true

		// add entries in pod firewall to run through required network policies
		for _, policy := range *npc.networkPoliciesInfo {
			if _, ok := policy.targetPods[pod.ip]; ok {
				comment := "run through nw policy " + policy.name
				policyChainName := networkPolicyChainName(policy.namespace, policy.name, version)
				args := []string{"-m", "comment", "--comment", comment, "-j", policyChainName}
				exists, err := iptablesCmdHandler.Exists("filter", podFwChainName, args...)
				if err != nil {
					return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
				}
				if !exists {
					err := iptablesCmdHandler.Insert("filter", podFwChainName, 1, args...)
					if err != nil && err.(*iptables.Error).ExitStatus() != 1 {
						return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
					}
				}
			}
		}

		// ensure there is rule in filter table and FORWARD chain to jump to pod specific firewall chain
		// this rule applies to the traffic getting routed (coming for other node pods)
		comment := "rule to jump traffic from POD name:" + pod.name + " namespace: " + pod.namespace +
			" to chain " + podFwChainName
		args := []string{"-m", "comment", "--comment", comment, "-s", pod.ip, "-j", podFwChainName}
		exists, err := iptablesCmdHandler.Exists("filter", "FORWARD", args...)
		if err != nil {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}
		if !exists {
			err := iptablesCmdHandler.Insert("filter", "FORWARD", 1, args...)
			if err != nil {
				return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
			}
		}

		// ensure there is rule in filter table and forward chain to jump to pod specific firewall chain
		// this rule applies to the traffic getting switched (coming for same node pods)
		comment = "rule to jump traffic from POD name:" + pod.name + " namespace: " + pod.namespace +
			" to chain " + podFwChainName
		args = []string{"-m", "physdev", "--physdev-is-bridged",
			"-m", "comment", "--comment", comment,
			"-s", pod.ip,
			"-j", podFwChainName}
		exists, err = iptablesCmdHandler.Exists("filter", "FORWARD", args...)
		if err != nil {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}
		if !exists {
			err = iptablesCmdHandler.Insert("filter", "FORWARD", 1, args...)
			if err != nil {
				return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
			}
		}

		// add default DROP rule at the end of chain
		comment = "default rule to REJECT traffic destined for POD name:" + pod.name + " namespace: " + pod.namespace
		args = []string{"-m", "comment", "--comment", comment, "-j", "REJECT"}
		err = iptablesCmdHandler.AppendUnique("filter", podFwChainName, args...)
		if err != nil {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}

		// ensure statefull firewall, that permits return traffic for the traffic originated by the pod
		comment = "rule for stateful firewall for pod"
		args = []string{"-m", "comment", "--comment", comment, "-m", "conntrack", "--ctstate", "RELATED,ESTABLISHED", "-j", "ACCEPT"}
		exists, err = iptablesCmdHandler.Exists("filter", podFwChainName, args...)
		if err != nil {
			return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
		}
		if !exists {
			err := iptablesCmdHandler.Insert("filter", podFwChainName, 1, args...)
			if err != nil {
				return nil, fmt.Errorf("Failed to run iptables command: %s", err.Error())
			}
		}
	}

	return activePodFwChains, nil
}

func cleanupStaleRules(activePolicyChains, activePodFwChains, activePolicyIPSets map[string]bool) error {

	cleanupPodFwChains := make([]string, 0)
	cleanupPolicyChains := make([]string, 0)
	cleanupPolicyIPSets := make([]*utils.Set, 0)

	iptablesCmdHandler, err := iptables.New()
	if err != nil {
		glog.Fatalf("failed to initialize iptables command executor due to %s", err.Error())
	}
	ipsets, err := utils.NewIPSet(false)
	if err != nil {
		glog.Fatalf("failed to create ipsets command executor due to %s", err.Error())
	}
	err = ipsets.Save()
	if err != nil {
		glog.Fatalf("failed to initialize ipsets command executor due to %s", err.Error())
	}

	// get the list of chains created for pod firewall and network policies
	chains, err := iptablesCmdHandler.ListChains("filter")
	for _, chain := range chains {
		if strings.HasPrefix(chain, kubeNetworkPolicyChainPrefix) {
			if _, ok := activePolicyChains[chain]; !ok {
				cleanupPolicyChains = append(cleanupPolicyChains, chain)
			}
		}
		if strings.HasPrefix(chain, kubePodFirewallChainPrefix) {
			if _, ok := activePodFwChains[chain]; !ok {
				cleanupPodFwChains = append(cleanupPodFwChains, chain)
			}
		}
	}
	for _, set := range ipsets.Sets {
		if strings.HasPrefix(set.Name, kubeSourceIpSetPrefix) ||
			strings.HasPrefix(set.Name, kubeDestinationIpSetPrefix) {
			if _, ok := activePolicyIPSets[set.Name]; !ok {
				cleanupPolicyIPSets = append(cleanupPolicyIPSets, set)
			}
		}
	}

	// cleanup FORWARD chain rules to jump to pod firewall
	for _, chain := range cleanupPodFwChains {

		forwardChainRules, err := iptablesCmdHandler.List("filter", "FORWARD")
		if err != nil {
			return fmt.Errorf("failed to list rules in filter table, FORWARD chain due to %s", err.Error())
		}
		outputChainRules, err := iptablesCmdHandler.List("filter", "OUTPUT")
		if err != nil {
			return fmt.Errorf("failed to list rules in filter table, OUTPUT chain due to %s", err.Error())
		}

		// TODO delete rule by spec, than rule number to avoid extra loop
		var realRuleNo int
		for i, rule := range forwardChainRules {
			if strings.Contains(rule, chain) {
				err = iptablesCmdHandler.Delete("filter", "FORWARD", strconv.Itoa(i-realRuleNo))
				if err != nil {
					return fmt.Errorf("failed to delete rule: %s from the FORWARD chain of filter table due to %s", rule, err.Error())
				}
				realRuleNo++
			}
		}
		realRuleNo = 0
		for i, rule := range outputChainRules {
			if strings.Contains(rule, chain) {
				err = iptablesCmdHandler.Delete("filter", "OUTPUT", strconv.Itoa(i-realRuleNo))
				if err != nil {
					return fmt.Errorf("failed to delete rule: %s from the OUTPUT chain of filter table due to %s", rule, err.Error())
				}
				realRuleNo++
			}
		}
	}

	// cleanup pod firewall chain
	for _, chain := range cleanupPodFwChains {
		glog.V(2).Infof("Found pod fw chain to cleanup: %s", chain)
		err = iptablesCmdHandler.ClearChain("filter", chain)
		if err != nil {
			return fmt.Errorf("Failed to flush the rules in chain %s due to %s", chain, err.Error())
		}
		err = iptablesCmdHandler.DeleteChain("filter", chain)
		if err != nil {
			return fmt.Errorf("Failed to delete the chain %s due to %s", chain, err.Error())
		}
		glog.V(2).Infof("Deleted pod specific firewall chain: %s from the filter table", chain)
	}

	// cleanup network policy chains
	for _, policyChain := range cleanupPolicyChains {
		glog.V(2).Infof("Found policy chain to cleanup %s", policyChain)

		// first clean up any references from pod firewall chain
		for podFwChain := range activePodFwChains {
			podFwChainRules, err := iptablesCmdHandler.List("filter", podFwChain)
			if err != nil {

			}
			for i, rule := range podFwChainRules {
				if strings.Contains(rule, policyChain) {
					err = iptablesCmdHandler.Delete("filter", podFwChain, strconv.Itoa(i))
					if err != nil {
						return fmt.Errorf("Failed to delete rule %s from the chain %s", rule, podFwChain)
					}
					break
				}
			}
		}

		err = iptablesCmdHandler.ClearChain("filter", policyChain)
		if err != nil {
			return fmt.Errorf("Failed to flush the rules in chain %s due to  %s", policyChain, err)
		}
		err = iptablesCmdHandler.DeleteChain("filter", policyChain)
		if err != nil {
			return fmt.Errorf("Failed to flush the rules in chain %s due to %s", policyChain, err)
		}
		glog.V(2).Infof("Deleted network policy chain: %s from the filter table", policyChain)
	}

	// cleanup network policy ipsets
	for _, set := range cleanupPolicyIPSets {
		err = set.Destroy()
		if err != nil {
			return fmt.Errorf("Failed to delete ipset %s due to %s", set.Name, err)
		}
	}
	return nil
}

func (npc *NetworkPolicyController) getIngressNetworkPolicyEnabledPods(nodeIp string) (*map[string]podInfo, error) {
	nodePods := make(map[string]podInfo)

	for _, obj := range npc.podLister.List() {
		pod := obj.(*api.Pod)

		if strings.Compare(pod.Status.HostIP, nodeIp) != 0 {
			continue
		}
		for _, policy := range *npc.networkPoliciesInfo {
			if policy.namespace != pod.ObjectMeta.Namespace {
				continue
			}
			_, ok := policy.targetPods[pod.Status.PodIP]
			if ok && (policy.policyType == "both" || policy.policyType == "ingress") {
				glog.V(2).Infof("Found pod name: " + pod.ObjectMeta.Name + " namespace: " + pod.ObjectMeta.Namespace + " for which network policies need to be applied.")
				nodePods[pod.Status.PodIP] = podInfo{ip: pod.Status.PodIP,
					name:      pod.ObjectMeta.Name,
					namespace: pod.ObjectMeta.Namespace,
					labels:    pod.ObjectMeta.Labels}
				break
			}
		}
	}
	return &nodePods, nil

}

func (npc *NetworkPolicyController) getEgressNetworkPolicyEnabledPods(nodeIp string) (*map[string]podInfo, error) {

	nodePods := make(map[string]podInfo)

	for _, obj := range npc.podLister.List() {
		pod := obj.(*api.Pod)

		if strings.Compare(pod.Status.HostIP, nodeIp) != 0 {
			continue
		}
		for _, policy := range *npc.networkPoliciesInfo {
			if policy.namespace != pod.ObjectMeta.Namespace {
				continue
			}
			_, ok := policy.targetPods[pod.Status.PodIP]
			if ok && (policy.policyType == "both" || policy.policyType == "egress") {
				glog.V(2).Infof("Found pod name: " + pod.ObjectMeta.Name + " namespace: " + pod.ObjectMeta.Namespace + " for which network policies need to be applied.")
				nodePods[pod.Status.PodIP] = podInfo{ip: pod.Status.PodIP,
					name:      pod.ObjectMeta.Name,
					namespace: pod.ObjectMeta.Namespace,
					labels:    pod.ObjectMeta.Labels}
				break
			}
		}
	}
	return &nodePods, nil
}

func (npc *NetworkPolicyController) buildNetworkPoliciesInfo() (*[]networkPolicyInfo, error) {

	NetworkPolicies := make([]networkPolicyInfo, 0)

	for _, policyObj := range npc.npLister.List() {

		policy, ok := policyObj.(*networking.NetworkPolicy)
		if !ok {
			return nil, fmt.Errorf("Failed to convert")
		}
		newPolicy := networkPolicyInfo{
			name:       policy.Name,
			namespace:  policy.Namespace,
			labels:     policy.Spec.PodSelector.MatchLabels,
			policyType: "ingress",
		}

		// check if there is explicitly specified PolicyTypes in the spec
		if len(policy.Spec.PolicyTypes) > 0 {
			ingressType, egressType := false, false
			for _, policyType := range policy.Spec.PolicyTypes {
				if policyType == networking.PolicyTypeIngress {
					ingressType = true
				}
				if policyType == networking.PolicyTypeEgress {
					egressType = true
				}
			}
			if ingressType && egressType {
				newPolicy.policyType = "both"
			} else if egressType {
				newPolicy.policyType = "egress"
			} else if ingressType {
				newPolicy.policyType = "ingress"
			}
		} else {
			if policy.Spec.Egress != nil && policy.Spec.Ingress != nil {
				newPolicy.policyType = "both"
			} else if policy.Spec.Egress != nil {
				newPolicy.policyType = "egress"
			} else if policy.Spec.Ingress != nil {
				newPolicy.policyType = "ingress"
			}
		}

		matchingPods, err := npc.ListPodsByNamespaceAndLabels(policy.Namespace, policy.Spec.PodSelector.MatchLabels)
		newPolicy.targetPods = make(map[string]podInfo)
		if err == nil {
			for _, matchingPod := range matchingPods {
				if matchingPod.Status.PodIP == "" {
					continue
				}
				newPolicy.targetPods[matchingPod.Status.PodIP] = podInfo{ip: matchingPod.Status.PodIP,
					name:      matchingPod.ObjectMeta.Name,
					namespace: matchingPod.ObjectMeta.Namespace,
					labels:    matchingPod.ObjectMeta.Labels}
			}
		}

		if policy.Spec.Ingress == nil {
			newPolicy.ingressRules = nil
		} else {
			newPolicy.ingressRules = make([]ingressRule, 0)
		}

		if policy.Spec.Egress == nil {
			newPolicy.egressRules = nil
		} else {
			newPolicy.egressRules = make([]egressRule, 0)
		}

		for _, specIngressRule := range policy.Spec.Ingress {
			ingressRule := ingressRule{}

			ingressRule.ports = make([]protocolAndPort, 0)

			// If this field is empty or missing in the spec, this rule matches all ports
			if len(specIngressRule.Ports) == 0 {
				ingressRule.matchAllPorts = true
			} else {
				ingressRule.matchAllPorts = false
				for _, port := range specIngressRule.Ports {
					protocolAndPort := protocolAndPort{protocol: string(*port.Protocol), port: port.Port.String()}
					ingressRule.ports = append(ingressRule.ports, protocolAndPort)
				}
			}

			ingressRule.srcPods = make([]podInfo, 0)
			ingressRule.srcIPBlocks = make([][]string, 0)

			// If this field is empty or missing in the spec, this rule matches all sources
			if len(specIngressRule.From) == 0 {
				ingressRule.matchAllSource = true
			} else {
				ingressRule.matchAllSource = false
				var matchingPods []*api.Pod
				for _, peer := range specIngressRule.From {
					peerPods, err := npc.evalPodPeer(policy, peer)
					matchingPods = append(matchingPods, peerPods...)
					ingressRule.srcIPBlocks = append(ingressRule.srcIPBlocks, npc.evalIPBlockPeer(peer)...)
					if err == nil {
						for _, matchingPod := range matchingPods {
							if matchingPod.Status.PodIP == "" {
								continue
							}
							ingressRule.srcPods = append(ingressRule.srcPods,
								podInfo{ip: matchingPod.Status.PodIP,
									name:      matchingPod.ObjectMeta.Name,
									namespace: matchingPod.ObjectMeta.Namespace,
									labels:    matchingPod.ObjectMeta.Labels})
						}
					}
				}
			}

			newPolicy.ingressRules = append(newPolicy.ingressRules, ingressRule)
		}

		for _, specEgressRule := range policy.Spec.Egress {
			egressRule := egressRule{}

			egressRule.ports = make([]protocolAndPort, 0)

			// If this field is empty or missing in the spec, this rule matches all ports
			if len(specEgressRule.Ports) == 0 {
				egressRule.matchAllPorts = true
			} else {
				egressRule.matchAllPorts = false
				for _, port := range specEgressRule.Ports {
					protocolAndPort := protocolAndPort{protocol: string(*port.Protocol), port: port.Port.String()}
					egressRule.ports = append(egressRule.ports, protocolAndPort)
				}
			}

			egressRule.dstPods = make([]podInfo, 0)
			egressRule.dstIPBlocks = make([][]string, 0)

			// If this field is empty or missing in the spec, this rule matches all sources
			if len(specEgressRule.To) == 0 {
				egressRule.matchAllDestinations = true
			} else {
				egressRule.matchAllDestinations = false
				var matchingPods []*api.Pod
				for _, peer := range specEgressRule.To {
					peerPods, err := npc.evalPodPeer(policy, peer)
					matchingPods = append(matchingPods, peerPods...)
					egressRule.dstIPBlocks = append(egressRule.dstIPBlocks, npc.evalIPBlockPeer(peer)...)
					if err == nil {
						for _, matchingPod := range matchingPods {
							egressRule.dstPods = append(egressRule.dstPods,
								podInfo{ip: matchingPod.Status.PodIP,
									name:      matchingPod.ObjectMeta.Name,
									namespace: matchingPod.ObjectMeta.Namespace,
									labels:    matchingPod.ObjectMeta.Labels})
						}
					}
				}
			}

			newPolicy.egressRules = append(newPolicy.egressRules, egressRule)
		}
		NetworkPolicies = append(NetworkPolicies, newPolicy)
	}

	return &NetworkPolicies, nil
}

func (npc *NetworkPolicyController) evalPodPeer(policy *networking.NetworkPolicy, peer networking.NetworkPolicyPeer) ([]*api.Pod, error) {

	var matchingPods []*api.Pod
	matchingPods = make([]*api.Pod, 0)
	var err error
	// spec can have both PodSelector AND NamespaceSelector
	if peer.NamespaceSelector != nil {
		namespaces, err := npc.ListNamespaceByLabels(peer.NamespaceSelector.MatchLabels)
		if err != nil {
			return nil, errors.New("Failed to build network policies info due to " + err.Error())
		}

		var podSelectorLabels map[string]string
		if peer.PodSelector != nil {
			podSelectorLabels = peer.PodSelector.MatchLabels
		}
		for _, namespace := range namespaces {
			namespacePods, err := npc.ListPodsByNamespaceAndLabels(namespace.Name, podSelectorLabels)
			if err != nil {
				return nil, errors.New("Failed to build network policies info due to " + err.Error())
			}
			matchingPods = append(matchingPods, namespacePods...)
		}
	} else if peer.PodSelector != nil {
		matchingPods, err = npc.ListPodsByNamespaceAndLabels(policy.Namespace, peer.PodSelector.MatchLabels)
	}

	return matchingPods, err
}

func (npc *NetworkPolicyController) ListPodsByNamespaceAndLabels(namespace string, labelsToMatch labels.Set) (ret []*api.Pod, err error) {
	podLister := listers.NewPodLister(npc.podLister)
	allMatchedNameSpacePods, err := podLister.Pods(namespace).List(labelsToMatch.AsSelector())
	if err != nil {
		return nil, err
	}
	return allMatchedNameSpacePods, nil
}

func (npc *NetworkPolicyController) ListNamespaceByLabels(set labels.Set) ([]*api.Namespace, error) {
	namespaceLister := listers.NewNamespaceLister(npc.nsLister)
	matchedNamespaces, err := namespaceLister.List(set.AsSelector())
	if err != nil {
		return nil, err
	}
	return matchedNamespaces, nil
}

func (npc *NetworkPolicyController) evalIPBlockPeer(peer networking.NetworkPolicyPeer) [][]string {
	ipBlock := make([][]string, 0)
	if peer.PodSelector == nil && peer.NamespaceSelector == nil && peer.IPBlock != nil {
		if cidr := peer.IPBlock.CIDR; strings.HasSuffix(cidr, "/0") {
			ipBlock = append(ipBlock, []string{"0.0.0.0/1", utils.OptionTimeout, "0"}, []string{"128.0.0.0/1", utils.OptionTimeout, "0"})
		} else {
			ipBlock = append(ipBlock, []string{cidr, utils.OptionTimeout, "0"})
		}
		for _, except := range peer.IPBlock.Except {
			if strings.HasSuffix(except, "/0") {
				ipBlock = append(ipBlock, []string{"0.0.0.0/1", utils.OptionTimeout, "0", utils.OptionNoMatch}, []string{"128.0.0.0/1", utils.OptionTimeout, "0", utils.OptionNoMatch})
			} else {
				ipBlock = append(ipBlock, []string{except, utils.OptionTimeout, "0", utils.OptionNoMatch})
			}
		}
	}
	return ipBlock
}

func (npc *NetworkPolicyController) buildBetaNetworkPoliciesInfo() (*[]networkPolicyInfo, error) {

	NetworkPolicies := make([]networkPolicyInfo, 0)

	for _, policyObj := range npc.npLister.List() {

		policy, _ := policyObj.(*apiextensions.NetworkPolicy)
		newPolicy := networkPolicyInfo{
			name:      policy.Name,
			namespace: policy.Namespace,
			labels:    policy.Spec.PodSelector.MatchLabels,
		}
		matchingPods, err := npc.ListPodsByNamespaceAndLabels(policy.Namespace, policy.Spec.PodSelector.MatchLabels)
		newPolicy.targetPods = make(map[string]podInfo)
		newPolicy.ingressRules = make([]ingressRule, 0)
		if err == nil {
			for _, matchingPod := range matchingPods {
				if matchingPod.Status.PodIP == "" {
					continue
				}
				newPolicy.targetPods[matchingPod.Status.PodIP] = podInfo{ip: matchingPod.Status.PodIP,
					name:      matchingPod.ObjectMeta.Name,
					namespace: matchingPod.ObjectMeta.Namespace,
					labels:    matchingPod.ObjectMeta.Labels}
			}
		}

		for _, specIngressRule := range policy.Spec.Ingress {
			ingressRule := ingressRule{}

			ingressRule.ports = make([]protocolAndPort, 0)
			for _, port := range specIngressRule.Ports {
				protocolAndPort := protocolAndPort{protocol: string(*port.Protocol), port: port.Port.String()}
				ingressRule.ports = append(ingressRule.ports, protocolAndPort)
			}

			ingressRule.srcPods = make([]podInfo, 0)
			for _, peer := range specIngressRule.From {
				matchingPods, err := npc.ListPodsByNamespaceAndLabels(policy.Namespace, peer.PodSelector.MatchLabels)
				if err == nil {
					for _, matchingPod := range matchingPods {
						if matchingPod.Status.PodIP == "" {
							continue
						}
						ingressRule.srcPods = append(ingressRule.srcPods,
							podInfo{ip: matchingPod.Status.PodIP,
								name:      matchingPod.ObjectMeta.Name,
								namespace: matchingPod.ObjectMeta.Namespace,
								labels:    matchingPod.ObjectMeta.Labels})
					}
				}
			}
			newPolicy.ingressRules = append(newPolicy.ingressRules, ingressRule)
		}
		NetworkPolicies = append(NetworkPolicies, newPolicy)
	}

	return &NetworkPolicies, nil
}

func podFirewallChainName(namespace, podName string, version string) string {
	hash := sha256.Sum256([]byte(namespace + podName + version))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubePodFirewallChainPrefix + encoded[:16]
}

func networkPolicyChainName(namespace, policyName string, version string) string {
	hash := sha256.Sum256([]byte(namespace + policyName + version))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubeNetworkPolicyChainPrefix + encoded[:16]
}

func policySourcePodIpSetName(namespace, policyName string) string {
	hash := sha256.Sum256([]byte(namespace + policyName))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubeSourceIpSetPrefix + encoded[:16]
}

func policyDestinationPodIpSetName(namespace, policyName string) string {
	hash := sha256.Sum256([]byte(namespace + policyName))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubeDestinationIpSetPrefix + encoded[:16]
}

func policyIndexedSourcePodIpSetName(namespace, policyName string, ingressRuleNo int) string {
	hash := sha256.Sum256([]byte(namespace + policyName + "ingressrule" + strconv.Itoa(ingressRuleNo) + "pod"))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubeSourceIpSetPrefix + encoded[:16]
}

func policyIndexedDestinationPodIpSetName(namespace, policyName string, egressRuleNo int) string {
	hash := sha256.Sum256([]byte(namespace + policyName + "egressrule" + strconv.Itoa(egressRuleNo) + "pod"))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubeDestinationIpSetPrefix + encoded[:16]
}

func policyIndexedSourceIpBlockIpSetName(namespace, policyName string, ingressRuleNo int) string {
	hash := sha256.Sum256([]byte(namespace + policyName + "ingressrule" + strconv.Itoa(ingressRuleNo) + "ipblock"))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubeSourceIpSetPrefix + encoded[:16]
}

func policyIndexedDestinationIpBlockIpSetName(namespace, policyName string, egressRuleNo int) string {
	hash := sha256.Sum256([]byte(namespace + policyName + "egressrule" + strconv.Itoa(egressRuleNo) + "ipblock"))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubeDestinationIpSetPrefix + encoded[:16]
}

// Cleanup cleanup configurations done
func (npc *NetworkPolicyController) Cleanup() {

	glog.Info("Cleaning up iptables configuration permanently done by kube-router")

	iptablesCmdHandler, err := iptables.New()
	if err != nil {
		glog.Errorf("Failed to initialize iptables executor: %s", err.Error())
	}

	// delete jump rules in FORWARD chain to pod specific firewall chain
	forwardChainRules, err := iptablesCmdHandler.List("filter", "FORWARD")
	if err != nil {
		glog.Errorf("Failed to delete iptable rules as part of cleanup")
		return
	}

	// TODO: need a better way to delte rule with out using number
	var realRuleNo int
	for i, rule := range forwardChainRules {
		if strings.Contains(rule, kubePodFirewallChainPrefix) {
			err = iptablesCmdHandler.Delete("filter", "FORWARD", strconv.Itoa(i-realRuleNo))
			realRuleNo++
		}
	}

	// delete jump rules in OUTPUT chain to pod specific firewall chain
	forwardChainRules, err = iptablesCmdHandler.List("filter", "OUTPUT")
	if err != nil {
		glog.Errorf("Failed to delete iptable rules as part of cleanup")
		return
	}

	// TODO: need a better way to delte rule with out using number
	realRuleNo = 0
	for i, rule := range forwardChainRules {
		if strings.Contains(rule, kubePodFirewallChainPrefix) {
			err = iptablesCmdHandler.Delete("filter", "OUTPUT", strconv.Itoa(i-realRuleNo))
			realRuleNo++
		}
	}

	// flush and delete pod specific firewall chain
	chains, err := iptablesCmdHandler.ListChains("filter")
	for _, chain := range chains {
		if strings.HasPrefix(chain, kubePodFirewallChainPrefix) {
			err = iptablesCmdHandler.ClearChain("filter", chain)
			if err != nil {
				glog.Errorf("Failed to cleanup iptable rules: " + err.Error())
				return
			}
			err = iptablesCmdHandler.DeleteChain("filter", chain)
			if err != nil {
				glog.Errorf("Failed to cleanup iptable rules: " + err.Error())
				return
			}
		}
	}

	// flush and delete per network policy specific chain
	chains, err = iptablesCmdHandler.ListChains("filter")
	for _, chain := range chains {
		if strings.HasPrefix(chain, kubeNetworkPolicyChainPrefix) {
			err = iptablesCmdHandler.ClearChain("filter", chain)
			if err != nil {
				glog.Errorf("Failed to cleanup iptable rules: " + err.Error())
				return
			}
			err = iptablesCmdHandler.DeleteChain("filter", chain)
			if err != nil {
				glog.Errorf("Failed to cleanup iptable rules: " + err.Error())
				return
			}
		}
	}

	// delete all ipsets
	ipset, err := utils.NewIPSet(false)
	if err != nil {
		glog.Errorf("Failed to clean up ipsets: " + err.Error())
	}
	err = ipset.Save()
	if err != nil {
		glog.Errorf("Failed to clean up ipsets: " + err.Error())
	}
	err = ipset.DestroyAllWithin()
	if err != nil {
		glog.Errorf("Failed to clean up ipsets: " + err.Error())
	}
	glog.Infof("Successfully cleaned the iptables configuration done by kube-router")
}

func (npc *NetworkPolicyController) newPodEventHandler() cache.ResourceEventHandler {
	return cache.ResourceEventHandlerFuncs{
		AddFunc: func(obj interface{}) {
			npc.OnPodUpdate(obj)

		},
		UpdateFunc: func(oldObj, newObj interface{}) {
			newPoObj := newObj.(*api.Pod)
			oldPoObj := oldObj.(*api.Pod)
			if newPoObj.Status.Phase != oldPoObj.Status.Phase || newPoObj.Status.PodIP != oldPoObj.Status.PodIP {
				// for the network policies, we are only interested in pod status phase change or IP change
				npc.OnPodUpdate(newObj)
			}
		},
		DeleteFunc: func(obj interface{}) {
			npc.OnPodUpdate(obj)
		},
	}
}

func (npc *NetworkPolicyController) newNamespaceEventHandler() cache.ResourceEventHandler {
	return cache.ResourceEventHandlerFuncs{
		AddFunc: func(obj interface{}) {
			npc.OnNamespaceUpdate(obj)

		},
		UpdateFunc: func(oldObj, newObj interface{}) {
			npc.OnNamespaceUpdate(newObj)

		},
		DeleteFunc: func(obj interface{}) {
			npc.OnNamespaceUpdate(obj)

		},
	}
}

func (npc *NetworkPolicyController) newNetworkPolicyEventHandler() cache.ResourceEventHandler {
	return cache.ResourceEventHandlerFuncs{
		AddFunc: func(obj interface{}) {
			npc.OnNetworkPolicyUpdate(obj)

		},
		UpdateFunc: func(oldObj, newObj interface{}) {
			npc.OnNetworkPolicyUpdate(newObj)
		},
		DeleteFunc: func(obj interface{}) {
			npc.OnNetworkPolicyUpdate(obj)

		},
	}
}

// NewNetworkPolicyController returns new NetworkPolicyController object
func NewNetworkPolicyController(clientset kubernetes.Interface,
	config *options.KubeRouterConfig, podInformer cache.SharedIndexInformer,
	npInformer cache.SharedIndexInformer, nsInformer cache.SharedIndexInformer) (*NetworkPolicyController, error) {
	npc := NetworkPolicyController{}

	if config.MetricsEnabled {
		//Register the metrics for this controller
		prometheus.MustRegister(metrics.ControllerIptablesSyncTime)
		prometheus.MustRegister(metrics.ControllerPolicyChainsSyncTime)
		npc.MetricsEnabled = true
	}

	npc.syncPeriod = config.IPTablesSyncPeriod

	npc.v1NetworkPolicy = true
	v, _ := clientset.Discovery().ServerVersion()
	valid := regexp.MustCompile("[0-9]")
	v.Minor = strings.Join(valid.FindAllString(v.Minor, -1), "")
	minorVer, _ := strconv.Atoi(v.Minor)
	if v.Major == "1" && minorVer < 7 {
		npc.v1NetworkPolicy = false
	}

	node, err := utils.GetNodeObject(clientset, config.HostnameOverride)
	if err != nil {
		return nil, err
	}

	npc.nodeHostName = node.Name

	nodeIP, err := utils.GetNodeIP(node)
	if err != nil {
		return nil, err
	}
	npc.nodeIP = nodeIP

	ipset, err := utils.NewIPSet(false)
	if err != nil {
		return nil, err
	}
	err = ipset.Save()
	if err != nil {
		return nil, err
	}
	npc.ipSetHandler = ipset

	npc.podLister = podInformer.GetIndexer()
	npc.PodEventHandler = npc.newPodEventHandler()

	npc.nsLister = nsInformer.GetIndexer()
	npc.NamespaceEventHandler = npc.newNamespaceEventHandler()

	npc.npLister = npInformer.GetIndexer()
	npc.NetworkPolicyEventHandler = npc.newNetworkPolicyEventHandler()

	return &npc, nil
}