| // Copyright 2020 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 pipe provides the implementation of pipe-like data-link layer |
| // endpoints. Such endpoints allow packets to be sent between two interfaces. |
| package pipe |
| |
| import ( |
| "gvisor.dev/gvisor/pkg/tcpip" |
| "gvisor.dev/gvisor/pkg/tcpip/buffer" |
| "gvisor.dev/gvisor/pkg/tcpip/header" |
| "gvisor.dev/gvisor/pkg/tcpip/stack" |
| ) |
| |
| var _ stack.LinkEndpoint = (*Endpoint)(nil) |
| |
| // New returns both ends of a new pipe. |
| func New(linkAddr1, linkAddr2 tcpip.LinkAddress) (*Endpoint, *Endpoint) { |
| ep1 := &Endpoint{ |
| linkAddr: linkAddr1, |
| } |
| ep2 := &Endpoint{ |
| linkAddr: linkAddr2, |
| } |
| ep1.linked = ep2 |
| ep2.linked = ep1 |
| return ep1, ep2 |
| } |
| |
| // Endpoint is one end of a pipe. |
| type Endpoint struct { |
| dispatcher stack.NetworkDispatcher |
| linked *Endpoint |
| linkAddr tcpip.LinkAddress |
| } |
| |
| func (e *Endpoint) deliverPackets(r stack.RouteInfo, proto tcpip.NetworkProtocolNumber, pkts stack.PacketBufferList) { |
| if !e.linked.IsAttached() { |
| return |
| } |
| |
| // Note that the local address from the perspective of this endpoint is the |
| // remote address from the perspective of the other end of the pipe |
| // (e.linked). Similarly, the remote address from the perspective of this |
| // endpoint is the local address on the other end. |
| // |
| // Deliver the packet in a new goroutine to escape this goroutine's stack and |
| // avoid a deadlock when a packet triggers a response which leads the stack to |
| // try and take a lock it already holds. |
| for pkt := pkts.Front(); pkt != nil; pkt = pkt.Next() { |
| e.linked.dispatcher.DeliverNetworkPacket(r.LocalLinkAddress /* remote */, r.RemoteLinkAddress /* local */, proto, stack.NewPacketBuffer(stack.PacketBufferOptions{ |
| Data: buffer.NewVectorisedView(pkt.Size(), pkt.Views()), |
| })) |
| } |
| } |
| |
| // WritePacket implements stack.LinkEndpoint. |
| func (e *Endpoint) WritePacket(r stack.RouteInfo, _ *stack.GSO, proto tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) tcpip.Error { |
| var pkts stack.PacketBufferList |
| pkts.PushBack(pkt) |
| e.deliverPackets(r, proto, pkts) |
| return nil |
| } |
| |
| // WritePackets implements stack.LinkEndpoint. |
| func (e *Endpoint) WritePackets(r stack.RouteInfo, _ *stack.GSO, pkts stack.PacketBufferList, proto tcpip.NetworkProtocolNumber) (int, tcpip.Error) { |
| n := pkts.Len() |
| e.deliverPackets(r, proto, pkts) |
| return n, nil |
| } |
| |
| // Attach implements stack.LinkEndpoint. |
| func (e *Endpoint) Attach(dispatcher stack.NetworkDispatcher) { |
| e.dispatcher = dispatcher |
| } |
| |
| // IsAttached implements stack.LinkEndpoint. |
| func (e *Endpoint) IsAttached() bool { |
| return e.dispatcher != nil |
| } |
| |
| // Wait implements stack.LinkEndpoint. |
| func (*Endpoint) Wait() {} |
| |
| // MTU implements stack.LinkEndpoint. |
| func (*Endpoint) MTU() uint32 { |
| return header.IPv6MinimumMTU |
| } |
| |
| // Capabilities implements stack.LinkEndpoint. |
| func (*Endpoint) Capabilities() stack.LinkEndpointCapabilities { |
| return 0 |
| } |
| |
| // MaxHeaderLength implements stack.LinkEndpoint. |
| func (*Endpoint) MaxHeaderLength() uint16 { |
| return 0 |
| } |
| |
| // LinkAddress implements stack.LinkEndpoint. |
| func (e *Endpoint) LinkAddress() tcpip.LinkAddress { |
| return e.linkAddr |
| } |
| |
| // ARPHardwareType implements stack.LinkEndpoint. |
| func (*Endpoint) ARPHardwareType() header.ARPHardwareType { |
| return header.ARPHardwareNone |
| } |
| |
| // AddHeader implements stack.LinkEndpoint. |
| func (*Endpoint) AddHeader(_, _ tcpip.LinkAddress, _ tcpip.NetworkProtocolNumber, _ *stack.PacketBuffer) { |
| } |