package netpol

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

	"github.com/cloudnativelabs/kube-router/v2/pkg/metrics"
	"github.com/cloudnativelabs/kube-router/v2/pkg/utils"
	api "k8s.io/api/core/v1"
	networking "k8s.io/api/networking/v1"
	v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/util/intstr"
	listers "k8s.io/client-go/listers/core/v1"
	"k8s.io/client-go/tools/cache"
	"k8s.io/klog/v2"
	netutils "k8s.io/utils/net"
)

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.handleNetworkPolicyDelete(obj)

		},
	}
}

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

	npc.RequestFullSync()
}

func (npc *NetworkPolicyController) handleNetworkPolicyDelete(obj interface{}) {
	netpol, ok := obj.(*networking.NetworkPolicy)
	if !ok {
		tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
		if !ok {
			klog.Errorf("unexpected object type: %v", obj)
			return
		}
		if netpol, ok = tombstone.Obj.(*networking.NetworkPolicy); !ok {
			klog.Errorf("unexpected object type: %v", obj)
			return
		}
	}
	klog.V(2).Infof("Received network policy: %s/%s delete event", netpol.Namespace, netpol.Name)

	npc.RequestFullSync()
}

// Configure iptables 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(networkPoliciesInfo []networkPolicyInfo,
	version string) (map[string]bool, map[string]bool, error) {
	start := time.Now()
	defer func() {
		endTime := time.Since(start)
		if npc.MetricsEnabled {
			metrics.ControllerPolicyChainsSyncTime.Observe(endTime.Seconds())
		}
		klog.V(2).Infof("Syncing network policy chains took %v", endTime)
	}()

	klog.V(1).Infof("Attempting to attain ipset mutex lock")
	npc.ipsetMutex.Lock()
	klog.V(1).Infof("Attained ipset mutex lock, continuing...")
	defer func() {
		npc.ipsetMutex.Unlock()
		klog.V(1).Infof("Returned ipset mutex lock")
	}()

	activePolicyChains := make(map[string]bool)
	activePolicyIPSets := make(map[string]bool)

	defer func() {
		if npc.MetricsEnabled {
			metrics.ControllerPolicyChains.Set(float64(len(activePolicyChains)))
			metrics.ControllerPolicyIpsets.Set(float64(len(activePolicyIPSets)))
		}
	}()

	// run through all network policies
	for _, policy := range networkPoliciesInfo {
		currentPodIPs := make(map[api.IPFamily][]string)
		for _, pod := range policy.targetPods {
			for _, ip := range pod.ips {
				if netutils.IsIPv4String(ip.IP) {
					currentPodIPs[api.IPv4Protocol] = append(currentPodIPs[api.IPv4Protocol], ip.IP)
				}
				if netutils.IsIPv6String(ip.IP) {
					currentPodIPs[api.IPv6Protocol] = append(currentPodIPs[api.IPv6Protocol], ip.IP)
				}
			}
		}

		for ipFamily := range npc.ipSetHandlers {
			// ensure there is a unique chain per network policy in filter table
			policyChainName := networkPolicyChainName(policy.namespace, policy.name, version, ipFamily)

			npc.filterTableRules[ipFamily].WriteString(":" + policyChainName + "\n")

			activePolicyChains[policyChainName] = true

			if policy.policyType == kubeBothPolicyType || policy.policyType == kubeIngressPolicyType {
				// create a ipset for all destination pod ip's matched by the policy spec PodSelector
				targetDestPodIPSetName := policyDestinationPodIPSetName(policy.namespace, policy.name, ipFamily)
				npc.createGenericHashIPSet(targetDestPodIPSetName, utils.TypeHashIP, currentPodIPs[ipFamily], ipFamily)

				if err := npc.processIngressRules(policy,
					targetDestPodIPSetName, activePolicyIPSets, version, ipFamily); err != nil {
					return nil, nil, err
				}
				activePolicyIPSets[targetDestPodIPSetName] = true
			}
			if policy.policyType == kubeBothPolicyType || policy.policyType == kubeEgressPolicyType {
				// create a ipset for all source pod ip's matched by the policy spec PodSelector
				targetSourcePodIPSetName := policySourcePodIPSetName(policy.namespace, policy.name, ipFamily)
				npc.createGenericHashIPSet(targetSourcePodIPSetName, utils.TypeHashIP, currentPodIPs[ipFamily], ipFamily)

				if err := npc.processEgressRules(policy,
					targetSourcePodIPSetName, activePolicyIPSets, version, ipFamily); err != nil {
					return nil, nil, err
				}
				activePolicyIPSets[targetSourcePodIPSetName] = true
			}
		}
	}

	for ipFamily, ipset := range npc.ipSetHandlers {
		ipFamily := ipFamily
		restoreStart := time.Now()
		err := ipset.Restore()
		restoreEndTime := time.Since(restoreStart)

		if npc.MetricsEnabled {
			switch ipFamily {
			case api.IPv4Protocol:
				metrics.ControllerPolicyIpsetV4RestoreTime.Observe(restoreEndTime.Seconds())
			case api.IPv6Protocol:
				metrics.ControllerPolicyIpsetV6RestoreTime.Observe(restoreEndTime.Seconds())
			}
		}
		klog.V(1).Infof("Restoring %v ipset took %v", ipFamily, restoreEndTime)

		if err != nil {
			return nil, nil, fmt.Errorf("failed to perform ipset restore: %w", err)
		}
	}

	klog.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,
	ipFamily api.IPFamily) 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
	}

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

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

		if len(ingressRule.srcPods) != 0 {
			srcPodIPSetName := policyIndexedSourcePodIPSetName(policy.namespace, policy.name, ruleIdx, ipFamily)
			activePolicyIPSets[srcPodIPSetName] = true
			setEntries := make([][]string, 0)
			ips := getIPsFromPods(ingressRule.srcPods, ipFamily)
			for _, ip := range ips {
				setEntries = append(setEntries, []string{ip, utils.OptionTimeout, "0"})
			}
			npc.ipSetHandlers[ipFamily].RefreshSet(srcPodIPSetName, setEntries, utils.TypeHashIP)

			// Create policy based ipset with source pod IPs
			npc.createPolicyIndexedIPSet(activePolicyIPSets, srcPodIPSetName, utils.TypeHashIP,
				getIPsFromPods(ingressRule.srcPods, ipFamily), ipFamily)

			// If the ingress policy contains port declarations, we need to make sure that we match on pod IP and port
			if len(ingressRule.ports) != 0 {
				if err := npc.createPodWithPortPolicyRule(ingressRule.ports, policy, policyChainName,
					srcPodIPSetName, targetDestPodIPSetName, ipFamily); err != nil {
					return err
				}
			}

			// If the ingress policy contains named port declarations, we need to make sure that we match on pod IP and
			// the resolved port number
			if len(ingressRule.namedPorts) != 0 {
				for epIdx, endPoints := range ingressRule.namedPorts {
					namedPortIPSetName := policyIndexedIngressNamedPortIPSetName(policy.namespace,
						policy.name, ruleIdx, epIdx, ipFamily)
					activePolicyIPSets[namedPortIPSetName] = true
					setEntries := make([][]string, 0)
					for _, ip := range endPoints.ips[ipFamily] {
						setEntries = append(setEntries, []string{ip, utils.OptionTimeout, "0"})
					}
					npc.ipSetHandlers[ipFamily].RefreshSet(namedPortIPSetName, setEntries, utils.TypeHashIP)

					comment := "rule to ACCEPT traffic from source pods to dest pods selected by policy name " +
						policy.name + " namespace " + policy.namespace
					if err := npc.appendRuleToPolicyChain(policyChainName, comment, srcPodIPSetName, namedPortIPSetName,
						endPoints.protocol, endPoints.port, endPoints.endport, ipFamily); err != nil {
						return err
					}
				}
			}

			// If the ingress policy contains no ports at all create the policy based only on IP
			if len(ingressRule.ports) == 0 && len(ingressRule.namedPorts) == 0 {
				// 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
				if err := npc.appendRuleToPolicyChain(policyChainName,
					comment, srcPodIPSetName, targetDestPodIPSetName, "", "", "", ipFamily); err != nil {
					return err
				}
			}
		}

		// case where only 'ports' details specified but no 'from' details in the ingress rule so match on all sources,
		// with specified port (if any) 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
				if err := npc.appendRuleToPolicyChain(policyChainName, comment, "", targetDestPodIPSetName,
					portProtocol.protocol, portProtocol.port, portProtocol.endport, ipFamily); err != nil {
					return err
				}
			}

			for epIdx, endPoints := range ingressRule.namedPorts {
				namedPortIPSetName := policyIndexedIngressNamedPortIPSetName(policy.namespace,
					policy.name, ruleIdx, epIdx, ipFamily)
				activePolicyIPSets[namedPortIPSetName] = true
				setEntries := make([][]string, 0)
				for _, ip := range endPoints.ips[ipFamily] {
					setEntries = append(setEntries, []string{ip, utils.OptionTimeout, "0"})
				}
				npc.ipSetHandlers[ipFamily].RefreshSet(namedPortIPSetName, setEntries, utils.TypeHashIP)

				comment := "rule to ACCEPT traffic from all sources to dest pods selected by policy name: " +
					policy.name + " namespace " + policy.namespace
				if err := npc.appendRuleToPolicyChain(policyChainName,
					comment, "", namedPortIPSetName, endPoints.protocol, endPoints.port, endPoints.endport, ipFamily); err != nil {
					return err
				}
			}
		}

		// case where neither ports nor from details are specified 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
			if err := npc.appendRuleToPolicyChain(policyChainName, comment, "", targetDestPodIPSetName,
				"", "", "", ipFamily); err != nil {
				return err
			}
		}

		if len(ingressRule.srcIPBlocks[ipFamily]) != 0 {
			srcIPBlockIPSetName := policyIndexedSourceIPBlockIPSetName(policy.namespace, policy.name, ruleIdx, ipFamily)
			activePolicyIPSets[srcIPBlockIPSetName] = true
			npc.ipSetHandlers[ipFamily].RefreshSet(srcIPBlockIPSetName, ingressRule.srcIPBlocks[ipFamily], utils.TypeHashNet)

			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
					if err := npc.appendRuleToPolicyChain(policyChainName, comment, srcIPBlockIPSetName,
						targetDestPodIPSetName, portProtocol.protocol, portProtocol.port,
						portProtocol.endport, ipFamily); err != nil {
						return err
					}
				}

				for epIdx, endPoints := range ingressRule.namedPorts {
					namedPortIPSetName := policyIndexedIngressNamedPortIPSetName(policy.namespace,
						policy.name, ruleIdx, epIdx, ipFamily)
					activePolicyIPSets[namedPortIPSetName] = true
					setEntries := make([][]string, 0)
					for _, ip := range endPoints.ips[ipFamily] {
						setEntries = append(setEntries, []string{ip, utils.OptionTimeout, "0"})
					}
					npc.ipSetHandlers[ipFamily].RefreshSet(namedPortIPSetName, setEntries, utils.TypeHashNet)
					comment := "rule to ACCEPT traffic from specified ipBlocks to dest pods selected by policy name: " +
						policy.name + " namespace " + policy.namespace
					if err := npc.appendRuleToPolicyChain(policyChainName, comment, srcIPBlockIPSetName, namedPortIPSetName,
						endPoints.protocol, endPoints.port, endPoints.endport, ipFamily); err != nil {
						return err
					}
				}
			}
			if ingressRule.matchAllPorts {
				comment := "rule to ACCEPT traffic from specified ipBlocks to dest pods selected by policy name: " +
					policy.name + " namespace " + policy.namespace
				if err := npc.appendRuleToPolicyChain(policyChainName, comment, srcIPBlockIPSetName,
					targetDestPodIPSetName, "", "", "", ipFamily); err != nil {
					return err
				}
			}
		}
	}

	return nil
}

func (npc *NetworkPolicyController) processEgressRules(policy networkPolicyInfo,
	targetSourcePodIPSetName string, activePolicyIPSets map[string]bool, version string,
	ipFamily api.IPFamily) 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
	}

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

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

		if len(egressRule.dstPods) != 0 {
			dstPodIPSetName := policyIndexedDestinationPodIPSetName(policy.namespace, policy.name, ruleIdx, ipFamily)
			activePolicyIPSets[dstPodIPSetName] = true
			setEntries := make([][]string, 0)
			ips := getIPsFromPods(egressRule.dstPods, ipFamily)
			for _, ip := range ips {
				setEntries = append(setEntries, []string{ip, utils.OptionTimeout, "0"})
			}
			npc.ipSetHandlers[ipFamily].RefreshSet(dstPodIPSetName, setEntries, utils.TypeHashIP)
			if len(egressRule.ports) != 0 {
				if err := npc.createPodWithPortPolicyRule(egressRule.ports, policy, policyChainName,
					targetSourcePodIPSetName, dstPodIPSetName, ipFamily); err != nil {
					return err
				}
			}

			// If the egress policy contains named port declarations, we need to make sure that we match on pod IP and
			// the resolved port number
			if len(egressRule.namedPorts) != 0 {
				for epIdx, endPoints := range egressRule.namedPorts {
					namedPortIPSetName := policyIndexedEgressNamedPortIPSetName(policy.namespace,
						policy.name, ruleIdx, epIdx, ipFamily)
					activePolicyIPSets[namedPortIPSetName] = true
					setEntries := make([][]string, 0)
					for _, ip := range endPoints.ips[ipFamily] {
						setEntries = append(setEntries, []string{ip, utils.OptionTimeout, "0"})
					}
					npc.ipSetHandlers[ipFamily].RefreshSet(namedPortIPSetName, setEntries, utils.TypeHashIP)
					comment := "rule to ACCEPT traffic from source pods to dest pods selected by policy name " +
						policy.name + " namespace " + policy.namespace
					if err := npc.appendRuleToPolicyChain(policyChainName, comment, targetSourcePodIPSetName,
						namedPortIPSetName, endPoints.protocol, endPoints.port, endPoints.endport, ipFamily); err != nil {
						return err
					}
				}
			}

			// If the egress policy contains no ports at all create the policy based only on IP
			if len(egressRule.ports) == 0 && len(egressRule.namedPorts) == 0 {
				// 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
				if err := npc.appendRuleToPolicyChain(policyChainName, comment, targetSourcePodIPSetName,
					dstPodIPSetName, "", "", "", ipFamily); err != nil {
					return err
				}
			}
		}

		// case where only 'ports' details specified but no 'to' details in the egress rule so match on all sources,
		// with specified port (if any) 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
				if err := npc.appendRuleToPolicyChain(policyChainName, comment, targetSourcePodIPSetName,
					"", portProtocol.protocol, portProtocol.port, portProtocol.endport, ipFamily); err != nil {
					return err
				}
			}
			for _, portProtocol := range egressRule.namedPorts {
				comment := "rule to ACCEPT traffic from source pods to all destinations selected by policy name: " +
					policy.name + " namespace " + policy.namespace
				if err := npc.appendRuleToPolicyChain(policyChainName, comment, targetSourcePodIPSetName,
					"", portProtocol.protocol, portProtocol.port, portProtocol.endport, ipFamily); err != nil {
					return err
				}
			}
		}

		// case where neither ports nor from details are specified 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
			if err := npc.appendRuleToPolicyChain(policyChainName, comment, targetSourcePodIPSetName,
				"", "", "", "", ipFamily); err != nil {
				return err
			}
		}

		if len(egressRule.dstIPBlocks[ipFamily]) != 0 {
			dstIPBlockIPSetName := policyIndexedDestinationIPBlockIPSetName(policy.namespace, policy.name, ruleIdx, ipFamily)
			activePolicyIPSets[dstIPBlockIPSetName] = true
			npc.ipSetHandlers[ipFamily].RefreshSet(dstIPBlockIPSetName, egressRule.dstIPBlocks[ipFamily], utils.TypeHashNet)
			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
					if err := npc.appendRuleToPolicyChain(policyChainName, comment, targetSourcePodIPSetName,
						dstIPBlockIPSetName, portProtocol.protocol, portProtocol.port,
						portProtocol.endport, ipFamily); err != nil {
						return err
					}
				}
			}
			if egressRule.matchAllPorts {
				comment := "rule to ACCEPT traffic from source pods to specified ipBlocks selected by policy name: " +
					policy.name + " namespace " + policy.namespace
				if err := npc.appendRuleToPolicyChain(policyChainName, comment, targetSourcePodIPSetName,
					dstIPBlockIPSetName, "", "", "", ipFamily); err != nil {
					return err
				}
			}
		}
	}
	return nil
}

func (npc *NetworkPolicyController) appendRuleToPolicyChain(policyChainName, comment, srcIPSetName, dstIPSetName,
	protocol, dPort, endDport string, ipFamily api.IPFamily) error {

	args := make([]string, 0)
	args = append(args, "-A", policyChainName)

	if comment != "" {
		args = append(args, "-m", "comment", "--comment", "\""+comment+"\"")
	}
	if srcIPSetName != "" {
		args = append(args, "-m", "set", "--match-set", srcIPSetName, "src")
	}
	if dstIPSetName != "" {
		args = append(args, "-m", "set", "--match-set", dstIPSetName, "dst")
	}
	if protocol != "" {
		args = append(args, "-p", protocol)
	}
	if dPort != "" {
		if endDport != "" {
			multiport := fmt.Sprintf("%s:%s", dPort, endDport)
			args = append(args, "--dport", multiport)
		} else {
			args = append(args, "--dport", dPort)
		}
	}

	//nolint:gocritic // we want to append to a separate array here so that we can re-use args below
	markArgs := append(args, "-j", "MARK", "--set-xmark", "0x10000/0x10000", "\n")
	npc.filterTableRules[ipFamily].WriteString(strings.Join(markArgs, " "))

	args = append(args, "-m", "mark", "--mark", "0x10000/0x10000", "-j", "RETURN", "\n")
	npc.filterTableRules[ipFamily].WriteString(strings.Join(args, " "))

	return nil
}

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

	NetworkPolicies := make([]networkPolicyInfo, 0)
	_, isIPv4Enabled := npc.ipSetHandlers[api.IPv4Protocol]
	_, isIPv6Enabled := npc.ipSetHandlers[api.IPv6Protocol]

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

		policy, ok := policyObj.(*networking.NetworkPolicy)
		podSelector, _ := v1.LabelSelectorAsSelector(&policy.Spec.PodSelector)
		if !ok {
			return nil, fmt.Errorf("failed to convert")
		}
		newPolicy := networkPolicyInfo{
			name:        policy.Name,
			namespace:   policy.Namespace,
			podSelector: podSelector,
			policyType:  kubeIngressPolicyType,
		}

		ingressType, egressType := false, false
		for _, policyType := range policy.Spec.PolicyTypes {
			if policyType == networking.PolicyTypeIngress {
				ingressType = true
			}
			if policyType == networking.PolicyTypeEgress {
				egressType = true
			}
		}
		switch {
		case ingressType && egressType:
			newPolicy.policyType = kubeBothPolicyType
		case egressType:
			newPolicy.policyType = kubeEgressPolicyType
		case ingressType:
			newPolicy.policyType = kubeIngressPolicyType
		}

		matchingPods, err := npc.ListPodsByNamespaceAndLabels(policy.Namespace, podSelector)
		newPolicy.targetPods = make(map[string]podInfo)
		namedPort2IngressEps := make(namedPort2eps)
		if err == nil {
			for _, matchingPod := range matchingPods {
				if !isNetPolActionable(matchingPod) {
					continue
				}
				newPolicy.targetPods[matchingPod.Status.PodIP] = podInfo{ips: matchingPod.Status.PodIPs,
					name:      matchingPod.ObjectMeta.Name,
					namespace: matchingPod.ObjectMeta.Namespace,
					labels:    matchingPod.ObjectMeta.Labels}
				npc.grabNamedPortFromPod(matchingPod, &namedPort2IngressEps)
			}
		}

		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.srcPods = make([]podInfo, 0)
			ingressRule.srcIPBlocks = make(map[api.IPFamily][][]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
				for _, peer := range specIngressRule.From {
					if peerPods, err := npc.evalPodPeer(policy, peer); err == nil {
						for _, peerPod := range peerPods {
							if !isNetPolActionable(peerPod) {
								continue
							}
							ingressRule.srcPods = append(ingressRule.srcPods,
								podInfo{ips: peerPod.Status.PodIPs,
									name:      peerPod.ObjectMeta.Name,
									namespace: peerPod.ObjectMeta.Namespace,
									labels:    peerPod.ObjectMeta.Labels})
						}
					}
					peerIPBlock := npc.evalIPBlockPeer(peer)

					_, foundIPv4Addresses := peerIPBlock[api.IPv4Protocol]
					_, foundIPv6Addresses := peerIPBlock[api.IPv6Protocol]
					if foundIPv4Addresses && !isIPv4Enabled {
						klog.Warningf("Ignoring IPv4 source IP blocks %s from policy %s because we are not IPv4 "+
							"Enabled!", peerIPBlock[api.IPv4Protocol], policy.Name)
					}
					if foundIPv6Addresses && !isIPv6Enabled {
						klog.Warningf("Ignoring IPv6 source IP blocks %s from policy %s because we are not IPv6 "+
							"Enabled!", peerIPBlock[api.IPv6Protocol], policy.Name)
					}

					ingressRule.srcIPBlocks[api.IPv4Protocol] = append(
						ingressRule.srcIPBlocks[api.IPv4Protocol],
						peerIPBlock[api.IPv4Protocol]...,
					)
					ingressRule.srcIPBlocks[api.IPv6Protocol] = append(
						ingressRule.srcIPBlocks[api.IPv6Protocol],
						peerIPBlock[api.IPv6Protocol]...,
					)
				}
			}

			ingressRule.ports = make([]protocolAndPort, 0)
			ingressRule.namedPorts = make([]endPoints, 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
				ingressRule.ports, ingressRule.namedPorts = npc.processNetworkPolicyPorts(
					specIngressRule.Ports, namedPort2IngressEps)
			}

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

		for _, specEgressRule := range policy.Spec.Egress {
			egressRule := egressRule{}
			egressRule.dstPods = make([]podInfo, 0)
			egressRule.dstIPBlocks = make(map[api.IPFamily][][]string, 0)
			namedPort2EgressEps := make(namedPort2eps)

			// If this field is empty or missing in the spec, this rule matches all sources
			if len(specEgressRule.To) == 0 {
				egressRule.matchAllDestinations = true
				// if rule.To is empty but rule.Ports not, we must try to grab NamedPort from pods that in same
				// namespace, so that we can design iptables rule to describe "match all dst but match some named
				// dst-port" egress rule
				if policyRulePortsHasNamedPort(specEgressRule.Ports) {
					matchingPeerPods, _ := npc.ListPodsByNamespaceAndLabels(policy.Namespace, labels.Everything())
					for _, peerPod := range matchingPeerPods {
						if !isNetPolActionable(peerPod) {
							continue
						}
						npc.grabNamedPortFromPod(peerPod, &namedPort2EgressEps)
					}
				}
			} else {
				egressRule.matchAllDestinations = false
				for _, peer := range specEgressRule.To {
					if peerPods, err := npc.evalPodPeer(policy, peer); err == nil {
						for _, peerPod := range peerPods {
							if !isNetPolActionable(peerPod) {
								continue
							}
							egressRule.dstPods = append(egressRule.dstPods,
								podInfo{ips: peerPod.Status.PodIPs,
									name:      peerPod.ObjectMeta.Name,
									namespace: peerPod.ObjectMeta.Namespace,
									labels:    peerPod.ObjectMeta.Labels})
							npc.grabNamedPortFromPod(peerPod, &namedPort2EgressEps)
						}

					}
					peerIPBlock := npc.evalIPBlockPeer(peer)

					_, foundIPv4Addresses := peerIPBlock[api.IPv4Protocol]
					_, foundIPv6Addresses := peerIPBlock[api.IPv6Protocol]
					if foundIPv4Addresses && !isIPv4Enabled {
						klog.Warningf("Ignoring IPv4 dest IP blocks %s from policy %s because we are not IPv4 "+
							"Enabled!", peerIPBlock[api.IPv4Protocol], policy.Name)
					}
					if foundIPv6Addresses && !isIPv6Enabled {
						klog.Warningf("Ignoring IPv6 dest IP blocks %s from policy %s because we are not IPv6 "+
							"Enabled!", peerIPBlock[api.IPv6Protocol], policy.Name)
					}

					egressRule.dstIPBlocks[api.IPv4Protocol] = append(
						egressRule.dstIPBlocks[api.IPv4Protocol],
						peerIPBlock[api.IPv4Protocol]...,
					)
					egressRule.dstIPBlocks[api.IPv6Protocol] = append(
						egressRule.dstIPBlocks[api.IPv6Protocol],
						peerIPBlock[api.IPv6Protocol]...,
					)
				}
			}

			egressRule.ports = make([]protocolAndPort, 0)
			egressRule.namedPorts = make([]endPoints, 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
				egressRule.ports, egressRule.namedPorts = npc.processNetworkPolicyPorts(
					specEgressRule.Ports, namedPort2EgressEps)
			}

			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 {
		namespaceSelector, _ := v1.LabelSelectorAsSelector(peer.NamespaceSelector)
		namespaces, err := npc.ListNamespaceByLabels(namespaceSelector)
		if err != nil {
			return nil, errors.New("Failed to build network policies info due to " + err.Error())
		}

		podSelector := labels.Everything()
		if peer.PodSelector != nil {
			podSelector, _ = v1.LabelSelectorAsSelector(peer.PodSelector)
		}
		for _, namespace := range namespaces {
			namespacePods, err := npc.ListPodsByNamespaceAndLabels(namespace.Name, podSelector)
			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 {
		podSelector, _ := v1.LabelSelectorAsSelector(peer.PodSelector)
		matchingPods, err = npc.ListPodsByNamespaceAndLabels(policy.Namespace, podSelector)
	}

	return matchingPods, err
}

func (npc *NetworkPolicyController) processNetworkPolicyPorts(npPorts []networking.NetworkPolicyPort,
	namedPort2eps namedPort2eps) (numericPorts []protocolAndPort, namedPorts []endPoints) {
	numericPorts, namedPorts = make([]protocolAndPort, 0), make([]endPoints, 0)
	for _, npPort := range npPorts {
		var protocol string
		if npPort.Protocol != nil {
			protocol = string(*npPort.Protocol)
		}
		if npPort.Port == nil {
			numericPorts = append(numericPorts, protocolAndPort{port: "", protocol: protocol})
		} else if npPort.Port.Type == intstr.Int {
			var portProto protocolAndPort
			if npPort.EndPort != nil {
				if *npPort.EndPort >= npPort.Port.IntVal {
					portProto.endport = strconv.Itoa(int(*npPort.EndPort))
				}
			}
			portProto.protocol, portProto.port = protocol, npPort.Port.String()
			numericPorts = append(numericPorts, portProto)
		} else if protocol2eps, ok := namedPort2eps[npPort.Port.String()]; ok {
			if numericPort2eps, ok := protocol2eps[protocol]; ok {
				for _, eps := range numericPort2eps {
					namedPorts = append(namedPorts, *eps)
				}
			}
		}
	}
	return
}

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

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

func (npc *NetworkPolicyController) evalIPBlockPeer(peer networking.NetworkPolicyPeer) map[api.IPFamily][][]string {
	ipBlock := make(map[api.IPFamily][][]string, 0)
	if peer.PodSelector == nil && peer.NamespaceSelector == nil && peer.IPBlock != nil {
		cidr := peer.IPBlock.CIDR

		if netutils.IsIPv4CIDRString(cidr) {
			if strings.HasSuffix(cidr, "/0") {
				ipBlock[api.IPv4Protocol] = append(
					ipBlock[api.IPv4Protocol],
					[]string{"0.0.0.0/1", utils.OptionTimeout, "0"},
					[]string{"128.0.0.0/1", utils.OptionTimeout, "0"},
				)
			} else {
				ipBlock[api.IPv4Protocol] = append(
					ipBlock[api.IPv4Protocol],
					[]string{cidr, utils.OptionTimeout, "0"},
				)
			}

			for _, except := range peer.IPBlock.Except {
				if strings.HasSuffix(except, "/0") {
					ipBlock[api.IPv4Protocol] = append(
						ipBlock[api.IPv4Protocol],
						[]string{"0.0.0.0/1", utils.OptionTimeout, "0", utils.OptionNoMatch},
						[]string{"128.0.0.0/1", utils.OptionTimeout, "0", utils.OptionNoMatch},
					)
				} else {
					ipBlock[api.IPv4Protocol] = append(
						ipBlock[api.IPv4Protocol],
						[]string{except, utils.OptionTimeout, "0", utils.OptionNoMatch},
					)
				}
			}
		}

		if netutils.IsIPv6CIDRString(cidr) {
			if strings.HasSuffix(cidr, "/0") {
				ipBlock[api.IPv6Protocol] = append(
					ipBlock[api.IPv6Protocol],
					[]string{"2000::/3", utils.OptionTimeout, "0"},
					[]string{"fd00::/8", utils.OptionTimeout, "0"},
				)
			} else {
				ipBlock[api.IPv6Protocol] = append(ipBlock[api.IPv6Protocol], []string{cidr, utils.OptionTimeout, "0"})
			}

			for _, except := range peer.IPBlock.Except {
				if strings.HasSuffix(except, "/0") {
					ipBlock[api.IPv6Protocol] = append(
						ipBlock[api.IPv6Protocol],
						[]string{"2000::/3", utils.OptionTimeout, "0", utils.OptionNoMatch},
						[]string{"fd00::/8", utils.OptionTimeout, "0", utils.OptionNoMatch},
					)
				} else {
					ipBlock[api.IPv6Protocol] = append(
						ipBlock[api.IPv6Protocol],
						[]string{except, utils.OptionTimeout, "0", utils.OptionNoMatch},
					)
				}
			}
		}
	}
	return ipBlock
}

func (npc *NetworkPolicyController) grabNamedPortFromPod(pod *api.Pod, namedPort2eps *namedPort2eps) {
	if pod == nil || namedPort2eps == nil {
		return
	}

	ips := make(map[api.IPFamily][]string)
	for _, ip := range pod.Status.PodIPs {
		if netutils.IsIPv4String(ip.IP) {
			ips[api.IPv4Protocol] = append(ips[api.IPv4Protocol], ip.IP)
		} else if netutils.IsIPv6String(ip.IP) {
			ips[api.IPv6Protocol] = append(ips[api.IPv6Protocol], ip.IP)
		}
	}

	for k := range pod.Spec.Containers {
		for _, port := range pod.Spec.Containers[k].Ports {
			name := port.Name
			protocol := string(port.Protocol)
			containerPort := strconv.Itoa(int(port.ContainerPort))

			if (*namedPort2eps)[name] == nil {
				(*namedPort2eps)[name] = make(protocol2eps)
			}
			if (*namedPort2eps)[name][protocol] == nil {
				(*namedPort2eps)[name][protocol] = make(numericPort2eps)
			}
			if eps, ok := (*namedPort2eps)[name][protocol][containerPort]; !ok {
				(*namedPort2eps)[name][protocol][containerPort] = &endPoints{
					ips:             ips,
					protocolAndPort: protocolAndPort{port: containerPort, protocol: protocol},
				}
			} else {
				eps.ips[api.IPv4Protocol] = append(eps.ips[api.IPv4Protocol], ips[api.IPv4Protocol]...)
				eps.ips[api.IPv6Protocol] = append(eps.ips[api.IPv6Protocol], ips[api.IPv6Protocol]...)
			}
		}
	}
}

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

func policySourcePodIPSetName(namespace, policyName string, ipFamily api.IPFamily) string {
	hash := sha256.Sum256([]byte(namespace + policyName + string(ipFamily)))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubeSourceIPSetPrefix + encoded[:16]
}

func policyDestinationPodIPSetName(namespace, policyName string, ipFamily api.IPFamily) string {
	hash := sha256.Sum256([]byte(namespace + policyName + string(ipFamily)))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubeDestinationIPSetPrefix + encoded[:16]
}

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

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

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

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

func policyIndexedIngressNamedPortIPSetName(
	namespace, policyName string, ingressRuleNo, namedPortNo int, ipFamily api.IPFamily) string {
	hash := sha256.Sum256([]byte(namespace + policyName + "ingressrule" + strconv.Itoa(ingressRuleNo) +
		strconv.Itoa(namedPortNo) + string(ipFamily) + "namedport"))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubeDestinationIPSetPrefix + encoded[:16]
}

func policyIndexedEgressNamedPortIPSetName(
	namespace, policyName string, egressRuleNo, namedPortNo int, ipFamily api.IPFamily) string {
	hash := sha256.Sum256([]byte(namespace + policyName + "egressrule" + strconv.Itoa(egressRuleNo) +
		strconv.Itoa(namedPortNo) + string(ipFamily) + "namedport"))
	encoded := base32.StdEncoding.EncodeToString(hash[:])
	return kubeDestinationIPSetPrefix + encoded[:16]
}

func policyRulePortsHasNamedPort(npPorts []networking.NetworkPolicyPort) bool {
	for _, npPort := range npPorts {
		if npPort.Port != nil && npPort.Port.Type == intstr.String {
			return true
		}
	}
	return false
}