diff options
Diffstat (limited to 'pkg/tcpip/link/qdisc/fifo')
| -rw-r--r-- | pkg/tcpip/link/qdisc/fifo/BUILD | 19 | ||||
| -rw-r--r-- | pkg/tcpip/link/qdisc/fifo/endpoint.go | 209 | ||||
| -rw-r--r-- | pkg/tcpip/link/qdisc/fifo/packet_buffer_queue.go | 84 |
3 files changed, 312 insertions, 0 deletions
diff --git a/pkg/tcpip/link/qdisc/fifo/BUILD b/pkg/tcpip/link/qdisc/fifo/BUILD new file mode 100644 index 000000000..054c213bc --- /dev/null +++ b/pkg/tcpip/link/qdisc/fifo/BUILD @@ -0,0 +1,19 @@ +load("//tools:defs.bzl", "go_library") + +package(licenses = ["notice"]) + +go_library( + name = "fifo", + srcs = [ + "endpoint.go", + "packet_buffer_queue.go", + ], + visibility = ["//visibility:public"], + deps = [ + "//pkg/sleep", + "//pkg/sync", + "//pkg/tcpip", + "//pkg/tcpip/buffer", + "//pkg/tcpip/stack", + ], +) diff --git a/pkg/tcpip/link/qdisc/fifo/endpoint.go b/pkg/tcpip/link/qdisc/fifo/endpoint.go new file mode 100644 index 000000000..be9fec3b3 --- /dev/null +++ b/pkg/tcpip/link/qdisc/fifo/endpoint.go @@ -0,0 +1,209 @@ +// 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 fifo provides the implementation of data-link layer endpoints that +// wrap another endpoint and queues all outbound packets and asynchronously +// dispatches them to the lower endpoint. +package fifo + +import ( + "gvisor.dev/gvisor/pkg/sleep" + "gvisor.dev/gvisor/pkg/sync" + "gvisor.dev/gvisor/pkg/tcpip" + "gvisor.dev/gvisor/pkg/tcpip/buffer" + "gvisor.dev/gvisor/pkg/tcpip/stack" +) + +// endpoint represents a LinkEndpoint which implements a FIFO queue for all +// outgoing packets. endpoint can have 1 or more underlying queueDispatchers. +// All outgoing packets are consistenly hashed to a single underlying queue +// using the PacketBuffer.Hash if set, otherwise all packets are queued to the +// first queue to avoid reordering in case of missing hash. +type endpoint struct { + dispatcher stack.NetworkDispatcher + lower stack.LinkEndpoint + wg sync.WaitGroup + dispatchers []*queueDispatcher +} + +// queueDispatcher is responsible for dispatching all outbound packets in its +// queue. It will also smartly batch packets when possible and write them +// through the lower LinkEndpoint. +type queueDispatcher struct { + lower stack.LinkEndpoint + q *packetBufferQueue + newPacketWaker sleep.Waker + closeWaker sleep.Waker +} + +// New creates a new fifo link endpoint with the n queues with maximum +// capacity of queueLen. +func New(lower stack.LinkEndpoint, n int, queueLen int) stack.LinkEndpoint { + e := &endpoint{ + lower: lower, + } + // Create the required dispatchers + for i := 0; i < n; i++ { + qd := &queueDispatcher{ + q: &packetBufferQueue{limit: queueLen}, + lower: lower, + } + e.dispatchers = append(e.dispatchers, qd) + e.wg.Add(1) + go func() { + defer e.wg.Done() + qd.dispatchLoop() + }() + } + return e +} + +func (q *queueDispatcher) dispatchLoop() { + const newPacketWakerID = 1 + const closeWakerID = 2 + s := sleep.Sleeper{} + s.AddWaker(&q.newPacketWaker, newPacketWakerID) + s.AddWaker(&q.closeWaker, closeWakerID) + defer s.Done() + + const batchSize = 32 + var batch stack.PacketBufferList + for { + id, ok := s.Fetch(true) + if ok && id == closeWakerID { + return + } + for pkt := q.q.dequeue(); pkt != nil; pkt = q.q.dequeue() { + batch.PushBack(pkt) + if batch.Len() < batchSize && !q.q.empty() { + continue + } + // We pass a protocol of zero here because each packet carries its + // NetworkProtocol. + q.lower.WritePackets(nil /* route */, nil /* gso */, batch, 0 /* protocol */) + for pkt := batch.Front(); pkt != nil; pkt = pkt.Next() { + pkt.EgressRoute.Release() + batch.Remove(pkt) + } + batch.Reset() + } + } +} + +// DeliverNetworkPacket implements stack.NetworkDispatcher.DeliverNetworkPacket. +func (e *endpoint) DeliverNetworkPacket(linkEP stack.LinkEndpoint, remote, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, pkt stack.PacketBuffer) { + e.dispatcher.DeliverNetworkPacket(e, remote, local, protocol, pkt) +} + +// Attach implements stack.LinkEndpoint.Attach. +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. +func (e *endpoint) MTU() uint32 { + return e.lower.MTU() +} + +// Capabilities implements stack.LinkEndpoint.Capabilities. +func (e *endpoint) Capabilities() stack.LinkEndpointCapabilities { + return e.lower.Capabilities() +} + +// MaxHeaderLength implements stack.LinkEndpoint.MaxHeaderLength. +func (e *endpoint) MaxHeaderLength() uint16 { + return e.lower.MaxHeaderLength() +} + +// LinkAddress implements stack.LinkEndpoint.LinkAddress. +func (e *endpoint) LinkAddress() tcpip.LinkAddress { + return e.lower.LinkAddress() +} + +// GSOMaxSize returns the maximum GSO packet size. +func (e *endpoint) GSOMaxSize() uint32 { + if gso, ok := e.lower.(stack.GSOEndpoint); ok { + return gso.GSOMaxSize() + } + return 0 +} + +// WritePacket implements stack.LinkEndpoint.WritePacket. +func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt stack.PacketBuffer) *tcpip.Error { + // WritePacket caller's do not set the following fields in PacketBuffer + // so we populate them here. + newRoute := r.Clone() + pkt.EgressRoute = &newRoute + pkt.GSOOptions = gso + pkt.NetworkProtocolNumber = protocol + d := e.dispatchers[int(pkt.Hash)%len(e.dispatchers)] + if !d.q.enqueue(&pkt) { + return tcpip.ErrNoBufferSpace + } + d.newPacketWaker.Assert() + return nil +} + +// WritePackets implements stack.LinkEndpoint.WritePackets. +// +// Being a batch API each packet in pkts should have the following fields +// populated: +// - pkt.EgressRoute +// - pkt.GSOOptions +// - pkt.NetworkProtocolNumber +func (e *endpoint) WritePackets(_ *stack.Route, _ *stack.GSO, pkts stack.PacketBufferList, _ tcpip.NetworkProtocolNumber) (int, *tcpip.Error) { + enqueued := 0 + for pkt := pkts.Front(); pkt != nil; { + d := e.dispatchers[int(pkt.Hash)%len(e.dispatchers)] + nxt := pkt.Next() + // Since qdisc can hold onto a packet for long we should Clone + // the route here to ensure it doesn't get released while the + // packet is still in our queue. + newRoute := pkt.EgressRoute.Clone() + pkt.EgressRoute = &newRoute + if !d.q.enqueue(pkt) { + if enqueued > 0 { + d.newPacketWaker.Assert() + } + return enqueued, tcpip.ErrNoBufferSpace + } + pkt = nxt + enqueued++ + d.newPacketWaker.Assert() + } + return enqueued, nil +} + +// WriteRawPacket implements stack.LinkEndpoint.WriteRawPacket. +func (e *endpoint) WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error { + return e.lower.WriteRawPacket(vv) +} + +// Wait implements stack.LinkEndpoint.Wait. +func (e *endpoint) Wait() { + e.lower.Wait() + + // The linkEP is gone. Teardown the outbound dispatcher goroutines. + for i := range e.dispatchers { + e.dispatchers[i].closeWaker.Assert() + } + + e.wg.Wait() +} diff --git a/pkg/tcpip/link/qdisc/fifo/packet_buffer_queue.go b/pkg/tcpip/link/qdisc/fifo/packet_buffer_queue.go new file mode 100644 index 000000000..eb5abb906 --- /dev/null +++ b/pkg/tcpip/link/qdisc/fifo/packet_buffer_queue.go @@ -0,0 +1,84 @@ +// 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 fifo + +import ( + "gvisor.dev/gvisor/pkg/sync" + "gvisor.dev/gvisor/pkg/tcpip/stack" +) + +// packetBufferQueue is a bounded, thread-safe queue of PacketBuffers. +// +type packetBufferQueue struct { + mu sync.Mutex + list stack.PacketBufferList + limit int + used int +} + +// emptyLocked determines if the queue is empty. +// Preconditions: q.mu must be held. +func (q *packetBufferQueue) emptyLocked() bool { + return q.used == 0 +} + +// empty determines if the queue is empty. +func (q *packetBufferQueue) empty() bool { + q.mu.Lock() + r := q.emptyLocked() + q.mu.Unlock() + + return r +} + +// setLimit updates the limit. No PacketBuffers are immediately dropped in case +// the queue becomes full due to the new limit. +func (q *packetBufferQueue) setLimit(limit int) { + q.mu.Lock() + q.limit = limit + q.mu.Unlock() +} + +// enqueue adds the given packet to the queue. +// +// Returns true when the PacketBuffer is successfully added to the queue, in +// which case ownership of the reference is transferred to the queue. And +// returns false if the queue is full, in which case ownership is retained by +// the caller. +func (q *packetBufferQueue) enqueue(s *stack.PacketBuffer) bool { + q.mu.Lock() + r := q.used < q.limit + if r { + q.list.PushBack(s) + q.used++ + } + q.mu.Unlock() + + return r +} + +// dequeue removes and returns the next PacketBuffer from queue, if one exists. +// Ownership is transferred to the caller. +func (q *packetBufferQueue) dequeue() *stack.PacketBuffer { + q.mu.Lock() + s := q.list.Front() + if s != nil { + q.list.Remove(s) + q.used-- + } + q.mu.Unlock() + + return s +} |