loadbalancer

type Backend struct {
	Address L3n4Addr

	// Instances of this backend. A backend is always linked to a specific
	// service and the instances may call the backend by different name
	// (PortName) or they may come from  differents sources.
	// Instances may contain multiple [BackendInstance]s per service
	// coming from different sources. The version from the source with the
	// highest priority (smallest uint8) is used. This is needed for smooth
	// transitions when ownership of endpoints is passed between upstream
	// data sources.
	Instances part.Map[BackendInstanceKey, BackendParams]
}

type BackendID uint32

type BackendInstanceKey struct {
	ServiceName    ServiceName
	SourcePriority uint8
}

type BackendParams struct {
	Address L3n4Addr

	// PortNames are the optional names for the ports. A frontend can specify which
	// backends to select by port name.
	PortNames []string

	// Weight of backend for load-balancing.
	Weight uint16

	// Node hosting this backend. This is used to determine backends local to
	// a node.
	NodeName string

	// Zone where backend is located.
	Zone string

	// ForZones where this backend should be consumed in
	ForZones []string

	// ClusterID of the cluster in which the backend is located. 0 for local cluster.
	ClusterID uint32

	// Source of the backend.
	Source source.Source

	// State of the backend, e.g. active, quarantined or terminating.
	State BackendState

	// Unhealthy marks a backend as unhealthy and overrides [State] to mark the backend
	// as quarantined. We require a separate field for active health checking to merge
	// with the original source of this backend. Negative is used here to allow the
	// zero value to mean that the backend is healthy.
	Unhealthy bool

	// UnhealthyUpdatedAt is the timestamp for when [Unhealthy] was last updated. Zero
	// value if never updated.
	// +deepequal-gen=false
	UnhealthyUpdatedAt time.Time
}

type BackendState uint8

type BackendStateFlags = uint8

type BackendsSeq2 iter.Seq2[BackendParams, statedb.Revision]

type Config struct {
	UserConfig

	// NodePortMin is the minimum port address for the NodePort range
	NodePortMin uint16

	// NodePortMax is the maximum port address for the NodePort range
	NodePortMax uint16
}

type DeprecatedConfig struct {
	// NodePortAlg indicates which backend selection algorithm is used
	// ("random" or "maglev")
	NodePortAlg string `mapstructure:"node-port-algorithm"`

	// NodePortMode indicates in which mode NodePort implementation should run
	// ("snat", "dsr" or "hybrid")
	NodePortMode string `mapstructure:"node-port-mode"`
}

type ExternalConfig struct {
	ZoneMapper

	EnableIPv4, EnableIPv6                 bool
	KubeProxyReplacement                   bool
	NodePortMin, NodePortMax               uint16
	NodePortAlg                            string
	LoadBalancerAlgorithmAnnotation        bool
	BPFSocketLBHostnsOnly                  bool
	EnableSocketLB                         bool
	EnableSocketLBPodConnectionTermination bool
	EnableHealthCheckLoadBalancerIP        bool

	// The following options will be removed in v1.19
	EnableHostPort              bool
	EnableSessionAffinity       bool
	EnableSVCSourceRangeCheck   bool
	EnableInternalTrafficPolicy bool
}

type FEPortName string

type Frontend struct {
	FrontendParams

	// Status is the reconciliation status for this frontend and
	// reflects whether or not the frontend and the associated backends
	// have been reconciled with the BPF maps.
	// Managed by [Writer].
	Status reconciler.Status

	// Backends associated with the frontend.
	Backends BackendsSeq2

	// HealthCheckBackends associated with the frontend that includes the ones that should be health checked.
	HealthCheckBackends BackendsSeq2

	// ID is the identifier allocated to this frontend. Used as the key
	// in the services BPF map. This field is populated by the reconciler
	// and is initially set to zero. It can be considered valid only when
	// [Status] is set to done.
	ID ServiceID

	// RedirectTo if set selects the backends from this service name instead
	// of that of [FrontendParams.ServiceName]. This is used to implement the
	// local redirect policies where traffic going to a specific service/frontend
	// is redirected to a local pod instead.
	RedirectTo *ServiceName

	// Service associated with the frontend. If service is updated
	// this pointer to the service will update as well and the
	// frontend is marked for reconciliation.
	Service *Service `json:"-" yaml:"-"`
}

type FrontendParams struct {
	// Frontend address and port
	Address L3n4Addr

	// Service type (e.g. ClusterIP, NodePort, ...)
	Type SVCType

	// Name of the associated service
	ServiceName ServiceName

	// PortName if set will select only backends with matching
	// port name.
	PortName FEPortName

	// ServicePort is the associated "ClusterIP" port of this frontend.
	// Same as [Address.L4Addr.Port] except when [Type] NodePort or
	//  This is used to match frontends with the [Ports] of
	// [Service.ProxyRedirect].
	ServicePort uint16
}

type IPFamily = bool

type InitWaitFunc hive.WaitFunc

type L3n4Addr unique.Handle[l3n4AddrRep]

type L4Addr struct {
	Protocol L4Type
	Port     uint16
}

type L4Type = string

type ProxyRedirect struct {
	ProxyPort uint16

	// Ports if non-empty will only redirect a frontend with a matching port.
	Ports []uint16
}

type SVCForwardingMode string

type SVCLoadBalancingAlgorithm uint8

type SVCNatPolicy string

type SVCProxyDelegation string

type SVCSourceRangesPolicy string

type SVCTrafficPolicy string

type SVCType string

type Service struct {
	// Name is the fully qualified service name, e.g. (<cluster>/)<namespace>/<name>.
	Name ServiceName

	// Source is the data source from which this service was ingested from.
	Source source.Source

	// Labels associated with the service.
	Labels labels.Labels

	// Annotations associated with this service.
	Annotations map[string]string

	// Selector specifies which pods should be associated with this service. If
	// this is empty the backends associated to this service are managed externally
	// and not by Kubernetes.
	Selector map[string]string

	// NatPolicy defines whether we need NAT46/64 translation for backends.
	NatPolicy SVCNatPolicy

	// ExtTrafficPolicy controls how backends are selected for North-South traffic.
	// If set to "Local", only node-local backends are chosen.
	ExtTrafficPolicy SVCTrafficPolicy

	// IntTrafficPolicy controls how backends are selected for East-West traffic.
	// If set to "Local", only node-local backends are chosen.
	IntTrafficPolicy SVCTrafficPolicy

	// ForwardingMode controls whether DSR or SNAT should be used for the dispatch
	// to the backend. If undefined the default mode is used (--bpf-lb-mode).
	ForwardingMode SVCForwardingMode

	// SessionAffinity if true will enable the client IP based session affinity.
	SessionAffinity bool

	// SessionAffinityTimeout is the duration of inactivity before the session
	// affinity is cleared for a specific client IP.
	SessionAffinityTimeout time.Duration

	// LoadBalancerClass if set specifies the load-balancer class to be used
	// for a LoadBalancer service. If unset the default implementation is used.
	LoadBalancerClass *string

	// ProxyRedirect if non-nil redirects the traffic going to the frontends
	// towards a locally running proxy.
	ProxyRedirect *ProxyRedirect

	// HealthCheckNodePort defines on which port the node runs a HTTP health
	// check server which may be used by external loadbalancers to determine
	// if a node has local backends. This will only have effect if both
	// LoadBalancerIPs is not empty and ExtTrafficPolicy is SVCTrafficPolicyLocal.
	HealthCheckNodePort uint16

	// LoopbackHostPort defines that HostPort frontends for this service should
	// only be exposed internally to the node.
	LoopbackHostPort bool

	// SourceRanges if non-empty will restrict access to the service to the specified
	// client addresses.
	SourceRanges []netip.Prefix

	// PortNames maps a port name to a port number.
	PortNames map[string]uint16

	// TrafficDistribution if not default will influence how backends are chosen for
	// frontends associated with this service.
	TrafficDistribution TrafficDistribution
}

type ServiceFlags uint16

type ServiceID uint16

type ServiceName struct {
	// contains filtered or unexported fields
}

type SvcFlagParam struct {
	SvcType          SVCType
	SvcNatPolicy     SVCNatPolicy
	SvcFwdModeDSR    bool
	SvcExtLocal      bool
	SvcIntLocal      bool
	SessionAffinity  bool
	IsRoutable       bool
	CheckSourceRange bool
	SourceRangeDeny  bool
	L7LoadBalancer   bool
	LoopbackHostport bool
	Quarantined      bool
}

type TestConfig struct {
	TestFaultProbability float32 `mapstructure:"lb-test-fault-probability"`
}

type TrafficDistribution string

type UserConfig struct {
	RetryBackoffMin time.Duration `mapstructure:"lb-retry-backoff-min"`
	RetryBackoffMax time.Duration `mapstructure:"lb-retry-backoff-max"`

	// LBMapEntries is the maximum number of entries allowed in BPF lbmap.
	LBMapEntries int `mapstructure:"bpf-lb-map-max"`

	// LBServiceMapEntries is the maximum number of entries allowed in BPF lbmap for services.
	LBServiceMapEntries int `mapstructure:"bpf-lb-service-map-max"`

	// LBBackendMapEntries is the maximum number of entries allowed in BPF lbmap for service backends.
	LBBackendMapEntries int `mapstructure:"bpf-lb-service-backend-map-max"`

	// LBRevNatEntries is the maximum number of entries allowed in BPF lbmap for reverse NAT.
	LBRevNatEntries int `mapstructure:"bpf-lb-rev-nat-map-max"`

	// LBAffinityMapEntries is the maximum number of entries allowed in BPF lbmap for session affinities.
	LBAffinityMapEntries int `mapstructure:"bpf-lb-affinity-map-max"`

	// LBSourceRangeAllTypes enables propagation of loadbalancerSourceRanges to all Kubernetes
	// service types which were created from the LoadBalancer service.
	LBSourceRangeAllTypes bool `mapstructure:"bpf-lb-source-range-all-types"`

	// LBSourceRangeMapEntries is the maximum number of entries allowed in BPF lbmap for source ranges.
	LBSourceRangeMapEntries int `mapstructure:"bpf-lb-source-range-map-max"`

	// LBMaglevMapEntries is the maximum number of entries allowed in BPF lbmap for maglev.
	LBMaglevMapEntries int `mapstructure:"bpf-lb-maglev-map-max"`

	// LBSockRevNatEntries is the maximum number of sock rev nat mappings
	// allowed in the BPF rev nat table
	LBSockRevNatEntries int `mapstructure:"bpf-sock-rev-map-max"`

	// NodePortRange is the minimum and maximum ports to use for NodePort
	NodePortRange []string

	// LBMode indicates in which mode NodePort implementation should run
	// ("snat", "dsr" or "hybrid")
	LBMode string `mapstructure:"bpf-lb-mode"`

	// LBModeAnnotation tells whether controller should check service
	// level annotation for configuring bpf load balancing algorithm.
	LBModeAnnotation bool `mapstructure:"bpf-lb-mode-annotation"`

	// LoadBalancerAlgorithm indicates which backend selection algorithm is used
	// ("random" or "maglev")
	LBAlgorithm string `mapstructure:"bpf-lb-algorithm"`

	// DSRDispatch indicates the method for pushing packets to
	// backends under DSR ("opt" or "ipip")
	DSRDispatch string `mapstructure:"bpf-lb-dsr-dispatch"`

	// ExternalClusterIP enables routing to ClusterIP services from outside
	// the cluster. This mirrors the behaviour of kube-proxy.
	ExternalClusterIP bool `mapstructure:"bpf-lb-external-clusterip"`

	// AlgorithmAnnotation tells whether controller should check service
	// level annotation for configuring bpf load balancing algorithm.
	AlgorithmAnnotation bool `mapstructure:"bpf-lb-algorithm-annotation"`

	// EnableHealthCheckNodePort enables health checking of NodePort by
	// cilium
	EnableHealthCheckNodePort bool `mapstructure:"enable-health-check-nodeport"`

	// LBPressureMetricsInterval sets the interval for updating the load-balancer BPF map
	// pressure metrics. A batch lookup is performed for all maps periodically to count
	// the number of elements that are then reported in the `bpf-map-pressure` metric.
	LBPressureMetricsInterval time.Duration `mapstructure:"lb-pressure-metrics-interval"`

	// Enable processing of service topology aware hints
	EnableServiceTopology bool

	// InitWaitTimeout is the amount of time we wait for the load-balancing tables to be initialized before
	// we start reconciling towards the BPF maps. This reduces the probability that load-balancing is scaled
	// down temporarily due to not yet seeing all backends.
	//
	// The delay happens only when existing BPF state existed.
	//
	// We must not wait forever for initialization though due to potential interdependencies between load-balancing
	// data sources. For example we might depend on Kubernetes data to connect to the ClusterMesh api-server and
	// thus may need to first reconcile the Kubernetes services to connect to ClusterMesh (if endpoints have changed
	// while agent was down).
	InitWaitTimeout time.Duration `mapstructure:"lb-init-wait-timeout"`
}

type ZoneMapper interface {
	GetZoneID(string) uint8
}