tcpip/transport/packet/endpoint.go - third_party/netstack - Git at Google

 // Copyright 2019 The gVisor Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 // Package packet provides the implementation of packet sockets (see
 // packet(7)). Packet sockets allow applications to:
 //
 //   * manually write and inspect link, network, and transport headers
 //   * receive all traffic of a given network protocol, or all protocols
 //
 // Packet sockets are similar to raw sockets, but provide even more power to
 // users, letting them effectively talk directly to the network device.
 //
 // Packet sockets skip the input and output iptables chains.
 package packet

 import (
 	"sync"

 	"github.com/google/netstack/tcpip"
 	"github.com/google/netstack/tcpip/buffer"
 	"github.com/google/netstack/tcpip/header"
 	"github.com/google/netstack/tcpip/iptables"
 	"github.com/google/netstack/tcpip/stack"
 	"github.com/google/netstack/waiter"
 )

 // +stateify savable
 type packet struct {
 	packetEntry
 	// data holds the actual packet data, including any headers and
 	// payload.
 	data buffer.VectorisedView
 	// views is pre-allocated space to back data. As long as the packet is
 	// made up of fewer than 8 buffer.Views, no extra allocation is
 	// necessary to store packet data.
 	views [8]buffer.View
 	// timestampNS is the unix time at which the packet was received.
 	timestampNS int64
 	// senderAddr is the network address of the sender.
 	senderAddr tcpip.FullAddress
 }

 // endpoint is the packet socket implementation of tcpip.Endpoint. It is legal
 // to have goroutines make concurrent calls into the endpoint.
 //
 // Lock order:
 //   endpoint.mu
 //     endpoint.rcvMu
 //
 // +stateify savable
 type endpoint struct {
 	stack.TransportEndpointInfo
 	// The following fields are initialized at creation time and are
 	// immutable.
 	stack       *stack.Stack
 	netProto    tcpip.NetworkProtocolNumber
 	waiterQueue *waiter.Queue
 	cooked      bool

 	// The following fields are used to manage the receive queue and are
 	// protected by rcvMu.
 	rcvMu         sync.Mutex
 	rcvList       packetList
 	rcvBufSizeMax int
 	rcvBufSize    int
 	rcvClosed     bool

 	// The following fields are protected by mu.
 	mu         sync.RWMutex
 	sndBufSize int
 	closed     bool
 	stats      tcpip.TransportEndpointStats
 }

 // NewEndpoint returns a new packet endpoint.
 func NewEndpoint(s *stack.Stack, cooked bool, netProto tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error) {
 	ep := &endpoint{
 		stack: s,
 		TransportEndpointInfo: stack.TransportEndpointInfo{
 			NetProto: netProto,
 		},
 		cooked:        cooked,
 		netProto:      netProto,
 		waiterQueue:   waiterQueue,
 		rcvBufSizeMax: 32 * 1024,
 		sndBufSize:    32 * 1024,
 	}

 	if err := s.RegisterPacketEndpoint(0, netProto, ep); err != nil {
 		return nil, err
 	}
 	return ep, nil
 }

 // Close implements tcpip.Endpoint.Close.
 func (ep *endpoint) Close() {
 	ep.mu.Lock()
 	defer ep.mu.Unlock()

 	if ep.closed {
 		return
 	}

 	ep.stack.UnregisterPacketEndpoint(0, ep.netProto, ep)

 	ep.rcvMu.Lock()
 	defer ep.rcvMu.Unlock()

 	// Clear the receive list.
 	ep.rcvClosed = true
 	ep.rcvBufSize = 0
 	for !ep.rcvList.Empty() {
 		ep.rcvList.Remove(ep.rcvList.Front())
 	}

 	ep.closed = true
 	ep.waiterQueue.Notify(waiter.EventHUp | waiter.EventErr | waiter.EventIn | waiter.EventOut)
 }

 // ModerateRecvBuf implements tcpip.Endpoint.ModerateRecvBuf.
 func (ep *endpoint) ModerateRecvBuf(copied int) {}

 // IPTables implements tcpip.Endpoint.IPTables.
 func (ep *endpoint) IPTables() (iptables.IPTables, error) {
 	return ep.stack.IPTables(), nil
 }

 // Read implements tcpip.Endpoint.Read.
 func (ep *endpoint) Read(addr *tcpip.FullAddress) (buffer.View, tcpip.ControlMessages, *tcpip.Error) {
 	ep.rcvMu.Lock()

 	// If there's no data to read, return that read would block or that the
 	// endpoint is closed.
 	if ep.rcvList.Empty() {
 		err := tcpip.ErrWouldBlock
 		if ep.rcvClosed {
 			ep.stats.ReadErrors.ReadClosed.Increment()
 			err = tcpip.ErrClosedForReceive
 		}
 		ep.rcvMu.Unlock()
 		return buffer.View{}, tcpip.ControlMessages{}, err
 	}

 	packet := ep.rcvList.Front()
 	ep.rcvList.Remove(packet)
 	ep.rcvBufSize -= packet.data.Size()

 	ep.rcvMu.Unlock()

 	if addr != nil {
 		*addr = packet.senderAddr
 	}

 	return packet.data.ToView(), tcpip.ControlMessages{HasTimestamp: true, Timestamp: packet.timestampNS}, nil
 }

 func (ep *endpoint) Write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-chan struct{}, *tcpip.Error) {
 	// TODO(b/129292371): Implement.
 	return 0, nil, tcpip.ErrInvalidOptionValue
 }

 // Peek implements tcpip.Endpoint.Peek.
 func (ep *endpoint) Peek([][]byte) (int64, tcpip.ControlMessages, *tcpip.Error) {
 	return 0, tcpip.ControlMessages{}, nil
 }

 // Disconnect implements tcpip.Endpoint.Disconnect. Packet sockets cannot be
 // disconnected, and this function always returns tpcip.ErrNotSupported.
 func (*endpoint) Disconnect() *tcpip.Error {
 	return tcpip.ErrNotSupported
 }

 // Connect implements tcpip.Endpoint.Connect. Packet sockets cannot be
 // connected, and this function always returnes tcpip.ErrNotSupported.
 func (ep *endpoint) Connect(addr tcpip.FullAddress) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }

 // Shutdown implements tcpip.Endpoint.Shutdown. Packet sockets cannot be used
 // with Shutdown, and this function always returns tcpip.ErrNotSupported.
 func (ep *endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }

 // Listen implements tcpip.Endpoint.Listen. Packet sockets cannot be used with
 // Listen, and this function always returns tcpip.ErrNotSupported.
 func (ep *endpoint) Listen(backlog int) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }

 // Accept implements tcpip.Endpoint.Accept. Packet sockets cannot be used with
 // Accept, and this function always returns tcpip.ErrNotSupported.
 func (ep *endpoint) Accept() (tcpip.Endpoint, *waiter.Queue, *tcpip.Error) {
 	return nil, nil, tcpip.ErrNotSupported
 }

 // Bind implements tcpip.Endpoint.Bind.
 func (ep *endpoint) Bind(addr tcpip.FullAddress) *tcpip.Error {
 	// TODO(gvisor.dev/issue/173): Add Bind support.

 	// "By default, all packets of the specified protocol type are passed
 	// to a packet socket.  To get packets only from a specific interface
 	// use bind(2) specifying an address in a struct sockaddr_ll to bind
 	// the packet socket  to  an interface.  Fields used for binding are
 	// sll_family (should be AF_PACKET), sll_protocol, and sll_ifindex."
 	// - packet(7).

 	return tcpip.ErrNotSupported
 }

 // GetLocalAddress implements tcpip.Endpoint.GetLocalAddress.
 func (ep *endpoint) GetLocalAddress() (tcpip.FullAddress, *tcpip.Error) {
 	return tcpip.FullAddress{}, tcpip.ErrNotSupported
 }

 // GetRemoteAddress implements tcpip.Endpoint.GetRemoteAddress.
 func (ep *endpoint) GetRemoteAddress() (tcpip.FullAddress, *tcpip.Error) {
 	// Even a connected socket doesn't return a remote address.
 	return tcpip.FullAddress{}, tcpip.ErrNotConnected
 }

 // Readiness implements tcpip.Endpoint.Readiness.
 func (ep *endpoint) Readiness(mask waiter.EventMask) waiter.EventMask {
 	// The endpoint is always writable.
 	result := waiter.EventOut & mask

 	// Determine whether the endpoint is readable.
 	if (mask & waiter.EventIn) != 0 {
 		ep.rcvMu.Lock()
 		if !ep.rcvList.Empty() || ep.rcvClosed {
 			result |= waiter.EventIn
 		}
 		ep.rcvMu.Unlock()
 	}

 	return result
 }

 // SetSockOpt implements tcpip.Endpoint.SetSockOpt. Packet sockets cannot be
 // used with SetSockOpt, and this function always returns
 // tcpip.ErrNotSupported.
 func (ep *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }

 // SetSockOptInt implements tcpip.Endpoint.SetSockOptInt.
 func (ep *endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error {
 	return tcpip.ErrUnknownProtocolOption
 }

 // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
 func (ep *endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) {
 	return 0, tcpip.ErrNotSupported
 }

 // GetSockOpt implements tcpip.Endpoint.GetSockOpt.
 func (ep *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 	return tcpip.ErrNotSupported
 }

 // HandlePacket implements stack.PacketEndpoint.HandlePacket.
 func (ep *endpoint) HandlePacket(nicid tcpip.NICID, localAddr tcpip.LinkAddress, netProto tcpip.NetworkProtocolNumber, vv buffer.VectorisedView, ethHeader buffer.View) {
 	ep.rcvMu.Lock()

 	// Drop the packet if our buffer is currently full.
 	if ep.rcvClosed {
 		ep.rcvMu.Unlock()
 		ep.stack.Stats().DroppedPackets.Increment()
 		ep.stats.ReceiveErrors.ClosedReceiver.Increment()
 		return
 	}

 	if ep.rcvBufSize >= ep.rcvBufSizeMax {
 		ep.rcvMu.Unlock()
 		ep.stack.Stats().DroppedPackets.Increment()
 		ep.stats.ReceiveErrors.ReceiveBufferOverflow.Increment()
 		return
 	}

 	wasEmpty := ep.rcvBufSize == 0

 	// Push new packet into receive list and increment the buffer size.
 	var packet packet
 	// TODO(b/129292371): Return network protocol.
 	if len(ethHeader) > 0 {
 		// Get info directly from the ethernet header.
 		hdr := header.Ethernet(ethHeader)
 		packet.senderAddr = tcpip.FullAddress{
 			NIC:  nicid,
 			Addr: tcpip.Address(hdr.SourceAddress()),
 		}
 	} else {
 		// Guess the would-be ethernet header.
 		packet.senderAddr = tcpip.FullAddress{
 			NIC:  nicid,
 			Addr: tcpip.Address(localAddr),
 		}
 	}

 	if ep.cooked {
 		// Cooked packets can simply be queued.
 		packet.data = vv.Clone(packet.views[:])
 	} else {
 		// Raw packets need their ethernet headers prepended before
 		// queueing.
 		if len(ethHeader) == 0 {
 			// We weren't provided with an actual ethernet header,
 			// so fake one.
 			ethFields := header.EthernetFields{
 				SrcAddr: tcpip.LinkAddress([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00}),
 				DstAddr: localAddr,
 				Type:    netProto,
 			}
 			fakeHeader := make(header.Ethernet, header.EthernetMinimumSize)
 			fakeHeader.Encode(&ethFields)
 			ethHeader = buffer.View(fakeHeader)
 		}
 		combinedVV := buffer.View(ethHeader).ToVectorisedView()
 		combinedVV.Append(vv)
 		packet.data = combinedVV.Clone(packet.views[:])
 	}
 	packet.timestampNS = ep.stack.NowNanoseconds()

 	ep.rcvList.PushBack(&packet)
 	ep.rcvBufSize += packet.data.Size()

 	ep.rcvMu.Unlock()
 	ep.stats.PacketsReceived.Increment()
 	// Notify waiters that there's data to be read.
 	if wasEmpty {
 		ep.waiterQueue.Notify(waiter.EventIn)
 	}
 }

 // State implements socket.Socket.State.
 func (ep *endpoint) State() uint32 {
 	return 0
 }

 // Info returns a copy of the endpoint info.
 func (ep *endpoint) Info() tcpip.EndpointInfo {
 	ep.mu.RLock()
 	// Make a copy of the endpoint info.
 	ret := ep.TransportEndpointInfo
 	ep.mu.RUnlock()
 	return &ret
 }

 // Stats returns a pointer to the endpoint stats.
 func (ep *endpoint) Stats() tcpip.EndpointStats {
 	return &ep.stats
 }
	// Copyright 2019 The gVisor Authors.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	// Package packet provides the implementation of packet sockets (see
	// packet(7)). Packet sockets allow applications to:
	//
	// * manually write and inspect link, network, and transport headers
	// * receive all traffic of a given network protocol, or all protocols
	//
	// Packet sockets are similar to raw sockets, but provide even more power to
	// users, letting them effectively talk directly to the network device.
	//
	// Packet sockets skip the input and output iptables chains.
	package packet

	import (
	"sync"

	"github.com/google/netstack/tcpip"
	"github.com/google/netstack/tcpip/buffer"
	"github.com/google/netstack/tcpip/header"
	"github.com/google/netstack/tcpip/iptables"
	"github.com/google/netstack/tcpip/stack"
	"github.com/google/netstack/waiter"
	)

	// +stateify savable
	type packet struct {
	packetEntry
	// data holds the actual packet data, including any headers and
	// payload.
	data buffer.VectorisedView
	// views is pre-allocated space to back data. As long as the packet is
	// made up of fewer than 8 buffer.Views, no extra allocation is
	// necessary to store packet data.
	views [8]buffer.View
	// timestampNS is the unix time at which the packet was received.
	timestampNS int64
	// senderAddr is the network address of the sender.
	senderAddr tcpip.FullAddress
	}

	// endpoint is the packet socket implementation of tcpip.Endpoint. It is legal
	// to have goroutines make concurrent calls into the endpoint.
	//
	// Lock order:
	// endpoint.mu
	// endpoint.rcvMu
	//
	// +stateify savable
	type endpoint struct {
	stack.TransportEndpointInfo
	// The following fields are initialized at creation time and are
	// immutable.
	stack *stack.Stack
	netProto tcpip.NetworkProtocolNumber
	waiterQueue *waiter.Queue
	cooked bool

	// The following fields are used to manage the receive queue and are
	// protected by rcvMu.
	rcvMu sync.Mutex
	rcvList packetList
	rcvBufSizeMax int
	rcvBufSize int
	rcvClosed bool

	// The following fields are protected by mu.
	mu sync.RWMutex
	sndBufSize int
	closed bool
	stats tcpip.TransportEndpointStats
	}

	// NewEndpoint returns a new packet endpoint.
	func NewEndpoint(s stack.Stack, cooked bool, netProto tcpip.NetworkProtocolNumber, waiterQueue waiter.Queue) (tcpip.Endpoint, *tcpip.Error) {
	ep := &endpoint{
	stack: s,
	TransportEndpointInfo: stack.TransportEndpointInfo{
	NetProto: netProto,
	},
	cooked: cooked,
	netProto: netProto,
	waiterQueue: waiterQueue,
	rcvBufSizeMax: 32 * 1024,
	sndBufSize: 32 * 1024,
	}

	if err := s.RegisterPacketEndpoint(0, netProto, ep); err != nil {
	return nil, err
	}
	return ep, nil
	}

	// Close implements tcpip.Endpoint.Close.
	func (ep *endpoint) Close() {
	ep.mu.Lock()
	defer ep.mu.Unlock()

	if ep.closed {
	return
	}

	ep.stack.UnregisterPacketEndpoint(0, ep.netProto, ep)

	ep.rcvMu.Lock()
	defer ep.rcvMu.Unlock()

	// Clear the receive list.
	ep.rcvClosed = true
	ep.rcvBufSize = 0
	for !ep.rcvList.Empty() {
	ep.rcvList.Remove(ep.rcvList.Front())
	}

	ep.closed = true
	ep.waiterQueue.Notify(waiter.EventHUp \| waiter.EventErr \| waiter.EventIn \| waiter.EventOut)
	}

	// ModerateRecvBuf implements tcpip.Endpoint.ModerateRecvBuf.
	func (ep *endpoint) ModerateRecvBuf(copied int) {}

	// IPTables implements tcpip.Endpoint.IPTables.
	func (ep *endpoint) IPTables() (iptables.IPTables, error) {
	return ep.stack.IPTables(), nil
	}

	// Read implements tcpip.Endpoint.Read.
	func (ep endpoint) Read(addr tcpip.FullAddress) (buffer.View, tcpip.ControlMessages, *tcpip.Error) {
	ep.rcvMu.Lock()

	// If there's no data to read, return that read would block or that the
	// endpoint is closed.
	if ep.rcvList.Empty() {
	err := tcpip.ErrWouldBlock
	if ep.rcvClosed {
	ep.stats.ReadErrors.ReadClosed.Increment()
	err = tcpip.ErrClosedForReceive
	}
	ep.rcvMu.Unlock()
	return buffer.View{}, tcpip.ControlMessages{}, err
	}

	packet := ep.rcvList.Front()
	ep.rcvList.Remove(packet)
	ep.rcvBufSize -= packet.data.Size()

	ep.rcvMu.Unlock()

	if addr != nil {
	*addr = packet.senderAddr
	}

	return packet.data.ToView(), tcpip.ControlMessages{HasTimestamp: true, Timestamp: packet.timestampNS}, nil
	}

	func (ep endpoint) Write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-chan struct{}, tcpip.Error) {
	// TODO(b/129292371): Implement.
	return 0, nil, tcpip.ErrInvalidOptionValue
	}

	// Peek implements tcpip.Endpoint.Peek.
	func (ep endpoint) Peek([][]byte) (int64, tcpip.ControlMessages, tcpip.Error) {
	return 0, tcpip.ControlMessages{}, nil
	}

	// Disconnect implements tcpip.Endpoint.Disconnect. Packet sockets cannot be
	// disconnected, and this function always returns tpcip.ErrNotSupported.
	func (endpoint) Disconnect() tcpip.Error {
	return tcpip.ErrNotSupported
	}

	// Connect implements tcpip.Endpoint.Connect. Packet sockets cannot be
	// connected, and this function always returnes tcpip.ErrNotSupported.
	func (ep endpoint) Connect(addr tcpip.FullAddress) tcpip.Error {
	return tcpip.ErrNotSupported
	}

	// Shutdown implements tcpip.Endpoint.Shutdown. Packet sockets cannot be used
	// with Shutdown, and this function always returns tcpip.ErrNotSupported.
	func (ep endpoint) Shutdown(flags tcpip.ShutdownFlags) tcpip.Error {
	return tcpip.ErrNotSupported
	}

	// Listen implements tcpip.Endpoint.Listen. Packet sockets cannot be used with
	// Listen, and this function always returns tcpip.ErrNotSupported.
	func (ep endpoint) Listen(backlog int) tcpip.Error {
	return tcpip.ErrNotSupported
	}

	// Accept implements tcpip.Endpoint.Accept. Packet sockets cannot be used with
	// Accept, and this function always returns tcpip.ErrNotSupported.
	func (ep endpoint) Accept() (tcpip.Endpoint, waiter.Queue, *tcpip.Error) {
	return nil, nil, tcpip.ErrNotSupported
	}

	// Bind implements tcpip.Endpoint.Bind.
	func (ep endpoint) Bind(addr tcpip.FullAddress) tcpip.Error {
	// TODO(gvisor.dev/issue/173): Add Bind support.

	// "By default, all packets of the specified protocol type are passed
	// to a packet socket. To get packets only from a specific interface
	// use bind(2) specifying an address in a struct sockaddr_ll to bind
	// the packet socket to an interface. Fields used for binding are
	// sll_family (should be AF_PACKET), sll_protocol, and sll_ifindex."
	// - packet(7).

	return tcpip.ErrNotSupported
	}

	// GetLocalAddress implements tcpip.Endpoint.GetLocalAddress.
	func (ep endpoint) GetLocalAddress() (tcpip.FullAddress, tcpip.Error) {
	return tcpip.FullAddress{}, tcpip.ErrNotSupported
	}

	// GetRemoteAddress implements tcpip.Endpoint.GetRemoteAddress.
	func (ep endpoint) GetRemoteAddress() (tcpip.FullAddress, tcpip.Error) {
	// Even a connected socket doesn't return a remote address.
	return tcpip.FullAddress{}, tcpip.ErrNotConnected
	}

	// Readiness implements tcpip.Endpoint.Readiness.
	func (ep *endpoint) Readiness(mask waiter.EventMask) waiter.EventMask {
	// The endpoint is always writable.
	result := waiter.EventOut & mask

	// Determine whether the endpoint is readable.
	if (mask & waiter.EventIn) != 0 {
	ep.rcvMu.Lock()
	if !ep.rcvList.Empty() \|\| ep.rcvClosed {
	result \|= waiter.EventIn
	}
	ep.rcvMu.Unlock()
	}

	return result
	}

	// SetSockOpt implements tcpip.Endpoint.SetSockOpt. Packet sockets cannot be
	// used with SetSockOpt, and this function always returns
	// tcpip.ErrNotSupported.
	func (ep endpoint) SetSockOpt(opt interface{}) tcpip.Error {
	return tcpip.ErrNotSupported
	}

	// SetSockOptInt implements tcpip.Endpoint.SetSockOptInt.
	func (ep endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) tcpip.Error {
	return tcpip.ErrUnknownProtocolOption
	}

	// GetSockOptInt implements tcpip.Endpoint.GetSockOptInt.
	func (ep endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, tcpip.Error) {
	return 0, tcpip.ErrNotSupported
	}

	// GetSockOpt implements tcpip.Endpoint.GetSockOpt.
	func (ep endpoint) GetSockOpt(opt interface{}) tcpip.Error {
	return tcpip.ErrNotSupported
	}

	// HandlePacket implements stack.PacketEndpoint.HandlePacket.
	func (ep *endpoint) HandlePacket(nicid tcpip.NICID, localAddr tcpip.LinkAddress, netProto tcpip.NetworkProtocolNumber, vv buffer.VectorisedView, ethHeader buffer.View) {
	ep.rcvMu.Lock()

	// Drop the packet if our buffer is currently full.
	if ep.rcvClosed {
	ep.rcvMu.Unlock()
	ep.stack.Stats().DroppedPackets.Increment()
	ep.stats.ReceiveErrors.ClosedReceiver.Increment()
	return
	}

	if ep.rcvBufSize >= ep.rcvBufSizeMax {
	ep.rcvMu.Unlock()
	ep.stack.Stats().DroppedPackets.Increment()
	ep.stats.ReceiveErrors.ReceiveBufferOverflow.Increment()
	return
	}

	wasEmpty := ep.rcvBufSize == 0

	// Push new packet into receive list and increment the buffer size.
	var packet packet
	// TODO(b/129292371): Return network protocol.
	if len(ethHeader) > 0 {
	// Get info directly from the ethernet header.
	hdr := header.Ethernet(ethHeader)
	packet.senderAddr = tcpip.FullAddress{
	NIC: nicid,
	Addr: tcpip.Address(hdr.SourceAddress()),
	}
	} else {
	// Guess the would-be ethernet header.
	packet.senderAddr = tcpip.FullAddress{
	NIC: nicid,
	Addr: tcpip.Address(localAddr),
	}
	}

	if ep.cooked {
	// Cooked packets can simply be queued.
	packet.data = vv.Clone(packet.views[:])
	} else {
	// Raw packets need their ethernet headers prepended before
	// queueing.
	if len(ethHeader) == 0 {
	// We weren't provided with an actual ethernet header,
	// so fake one.
	ethFields := header.EthernetFields{
	SrcAddr: tcpip.LinkAddress([]byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00}),
	DstAddr: localAddr,
	Type: netProto,
	}
	fakeHeader := make(header.Ethernet, header.EthernetMinimumSize)
	fakeHeader.Encode(&ethFields)
	ethHeader = buffer.View(fakeHeader)
	}
	combinedVV := buffer.View(ethHeader).ToVectorisedView()
	combinedVV.Append(vv)
	packet.data = combinedVV.Clone(packet.views[:])
	}
	packet.timestampNS = ep.stack.NowNanoseconds()

	ep.rcvList.PushBack(&packet)
	ep.rcvBufSize += packet.data.Size()

	ep.rcvMu.Unlock()
	ep.stats.PacketsReceived.Increment()
	// Notify waiters that there's data to be read.
	if wasEmpty {
	ep.waiterQueue.Notify(waiter.EventIn)
	}
	}

	// State implements socket.Socket.State.
	func (ep *endpoint) State() uint32 {
	return 0
	}

	// Info returns a copy of the endpoint info.
	func (ep *endpoint) Info() tcpip.EndpointInfo {
	ep.mu.RLock()
	// Make a copy of the endpoint info.
	ret := ep.TransportEndpointInfo
	ep.mu.RUnlock()
	return &ret
	}

	// Stats returns a pointer to the endpoint stats.
	func (ep *endpoint) Stats() tcpip.EndpointStats {
	return &ep.stats
	}