const (
    // ListenerProtocolUnknown is an unknown type of listener.
    ListenerProtocolUnknown = iota
    // ListenerProtocolTCP is a TCP listener.
    ListenerProtocolTCP
    // ListenerProtocolHTTP is an HTTP listener.
    ListenerProtocolHTTP
    // ListenerProtocolThrift is a Thrift listener.
    ListenerProtocolThrift
    // ListenerProtocolAuto enables auto protocol detection
    ListenerProtocolAuto
)

const (
    NoTunnelTypeName = "notunnel"
    H2TunnelTypeName = "H2Tunnel"
)

type FilterChain struct {
    // FilterChainMatch is the match used to select the filter chain.
    FilterChainMatch *listener.FilterChainMatch
    // TLSContext is the TLS settings for this filter chains.
    TLSContext *tls.DownstreamTlsContext
    // ListenerFilters are the filters needed for the whole listener, not particular to this
    // filter chain.
    ListenerFilters []*listener.ListenerFilter
    // ListenerProtocol indicates whether this filter chain is for HTTP or TCP
    // Note that HTTP filter chains can also have network filters
    ListenerProtocol ListenerProtocol
    // IstioMutualGateway is set only when this filter chain is part of a Gateway, and
    // the Server corresponding to this filter chain is doing TLS termination with ISTIO_MUTUAL as the TLS mode.
    // This allows the authN plugin to add the istio_authn filter to gateways in addition to sidecars.
    IstioMutualGateway bool

    // HTTP is the set of HTTP filters for this filter chain
    HTTP []*http_conn.HttpFilter
    // Thrift is the set of Thrift filters for this filter chain
    Thrift []*thrift_proxy.ThriftFilter
    // TCP is the set of network (TCP) filters for this filter chain.
    TCP []*listener.Filter
    // IsFallthrough indicates if the filter chain is fallthrough.
    IsFallThrough bool
}

type ListenerProtocol int

type MutableObjects struct {
    // Listener is the listener being built. Must be initialized before Plugin methods are called.
    Listener *listener.Listener

    // FilterChains is the set of filter chains that will be attached to Listener.
    FilterChains []FilterChain
}

type TunnelAbility int

type TunnelType int

const (
    // Bind the no tunnel support to a name.
    NoTunnel TunnelType = 0
    // Enumeration of tunnel type below. Each type should own a unique bit field.
    H2Tunnel TunnelType = 1 << 0
)