150 lines
5.2 KiB
Go
150 lines
5.2 KiB
Go
// Copyright 2018 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 waitable provides the implementation of data-link layer endpoints
|
|
// that wrap other endpoints, and can wait for inflight calls to WritePacket or
|
|
// DeliverNetworkPacket to finish (and new ones to be prevented).
|
|
//
|
|
// Waitable endpoints can be used in the networking stack by calling New(eID) to
|
|
// create a new endpoint, where eID is the ID of the endpoint being wrapped,
|
|
// and then passing it as an argument to Stack.CreateNIC().
|
|
package waitable
|
|
|
|
import (
|
|
"gvisor.dev/gvisor/pkg/gate"
|
|
"gvisor.dev/gvisor/pkg/tcpip"
|
|
"gvisor.dev/gvisor/pkg/tcpip/buffer"
|
|
"gvisor.dev/gvisor/pkg/tcpip/stack"
|
|
)
|
|
|
|
// Endpoint is a waitable link-layer endpoint.
|
|
type Endpoint struct {
|
|
dispatchGate gate.Gate
|
|
dispatcher stack.NetworkDispatcher
|
|
|
|
writeGate gate.Gate
|
|
lower stack.LinkEndpoint
|
|
}
|
|
|
|
// New creates a new waitable link-layer endpoint. It wraps around another
|
|
// endpoint and allows the caller to block new write/dispatch calls and wait for
|
|
// the inflight ones to finish before returning.
|
|
func New(lower stack.LinkEndpoint) *Endpoint {
|
|
return &Endpoint{
|
|
lower: lower,
|
|
}
|
|
}
|
|
|
|
// DeliverNetworkPacket implements stack.NetworkDispatcher.DeliverNetworkPacket.
|
|
// It is called by the link-layer endpoint being wrapped when a packet arrives,
|
|
// and only forwards to the actual dispatcher if Wait or WaitDispatch haven't
|
|
// been called.
|
|
func (e *Endpoint) DeliverNetworkPacket(linkEP stack.LinkEndpoint, remote, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, vv buffer.VectorisedView, linkHeader buffer.View) {
|
|
if !e.dispatchGate.Enter() {
|
|
return
|
|
}
|
|
|
|
e.dispatcher.DeliverNetworkPacket(e, remote, local, protocol, vv, linkHeader)
|
|
e.dispatchGate.Leave()
|
|
}
|
|
|
|
// Attach implements stack.LinkEndpoint.Attach. It saves the dispatcher and
|
|
// registers with the lower endpoint as its dispatcher so that "e" is called
|
|
// for inbound packets.
|
|
func (e *Endpoint) Attach(dispatcher stack.NetworkDispatcher) {
|
|
e.dispatcher = dispatcher
|
|
e.lower.Attach(e)
|
|
}
|
|
|
|
// IsAttached implements stack.LinkEndpoint.IsAttached.
|
|
func (e *Endpoint) IsAttached() bool {
|
|
return e.dispatcher != nil
|
|
}
|
|
|
|
// MTU implements stack.LinkEndpoint.MTU. It just forwards the request to the
|
|
// lower endpoint.
|
|
func (e *Endpoint) MTU() uint32 {
|
|
return e.lower.MTU()
|
|
}
|
|
|
|
// Capabilities implements stack.LinkEndpoint.Capabilities. It just forwards the
|
|
// request to the lower endpoint.
|
|
func (e *Endpoint) Capabilities() stack.LinkEndpointCapabilities {
|
|
return e.lower.Capabilities()
|
|
}
|
|
|
|
// MaxHeaderLength implements stack.LinkEndpoint.MaxHeaderLength. It just
|
|
// forwards the request to the lower endpoint.
|
|
func (e *Endpoint) MaxHeaderLength() uint16 {
|
|
return e.lower.MaxHeaderLength()
|
|
}
|
|
|
|
// LinkAddress implements stack.LinkEndpoint.LinkAddress. It just forwards the
|
|
// request to the lower endpoint.
|
|
func (e *Endpoint) LinkAddress() tcpip.LinkAddress {
|
|
return e.lower.LinkAddress()
|
|
}
|
|
|
|
// WritePacket implements stack.LinkEndpoint.WritePacket. It is called by
|
|
// higher-level protocols to write packets. It only forwards packets to the
|
|
// lower endpoint if Wait or WaitWrite haven't been called.
|
|
func (e *Endpoint) WritePacket(r *stack.Route, gso *stack.GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) *tcpip.Error {
|
|
if !e.writeGate.Enter() {
|
|
return nil
|
|
}
|
|
|
|
err := e.lower.WritePacket(r, gso, hdr, payload, protocol)
|
|
e.writeGate.Leave()
|
|
return err
|
|
}
|
|
|
|
// WritePackets implements stack.LinkEndpoint.WritePackets. It is called by
|
|
// higher-level protocols to write packets. It only forwards packets to the
|
|
// lower endpoint if Wait or WaitWrite haven't been called.
|
|
func (e *Endpoint) WritePackets(r *stack.Route, gso *stack.GSO, hdrs []stack.PacketDescriptor, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error) {
|
|
if !e.writeGate.Enter() {
|
|
return len(hdrs), nil
|
|
}
|
|
|
|
n, err := e.lower.WritePackets(r, gso, hdrs, payload, protocol)
|
|
e.writeGate.Leave()
|
|
return n, err
|
|
}
|
|
|
|
// WriteRawPacket implements stack.LinkEndpoint.WriteRawPacket.
|
|
func (e *Endpoint) WriteRawPacket(packet buffer.VectorisedView) *tcpip.Error {
|
|
if !e.writeGate.Enter() {
|
|
return nil
|
|
}
|
|
|
|
err := e.lower.WriteRawPacket(packet)
|
|
e.writeGate.Leave()
|
|
return err
|
|
}
|
|
|
|
// WaitWrite prevents new calls to WritePacket from reaching the lower endpoint,
|
|
// and waits for inflight ones to finish before returning.
|
|
func (e *Endpoint) WaitWrite() {
|
|
e.writeGate.Close()
|
|
}
|
|
|
|
// WaitDispatch prevents new calls to DeliverNetworkPacket from reaching the
|
|
// actual dispatcher, and waits for inflight ones to finish before returning.
|
|
func (e *Endpoint) WaitDispatch() {
|
|
e.dispatchGate.Close()
|
|
}
|
|
|
|
// Wait implements stack.LinkEndpoint.Wait.
|
|
func (e *Endpoint) Wait() {}
|