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Diffstat (limited to 'pkg/tcpip/link/sharedmem/sharedmem.go')
-rw-r--r-- | pkg/tcpip/link/sharedmem/sharedmem.go | 264 |
1 files changed, 0 insertions, 264 deletions
diff --git a/pkg/tcpip/link/sharedmem/sharedmem.go b/pkg/tcpip/link/sharedmem/sharedmem.go deleted file mode 100644 index ba387af73..000000000 --- a/pkg/tcpip/link/sharedmem/sharedmem.go +++ /dev/null @@ -1,264 +0,0 @@ -// 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. - -// +build linux - -// Package sharedmem provides the implemention of data-link layer endpoints -// backed by shared memory. -// -// Shared memory endpoints can be used in the networking stack by calling New() -// to create a new endpoint, and then passing it as an argument to -// Stack.CreateNIC(). -package sharedmem - -import ( - "sync" - "sync/atomic" - "syscall" - - "gvisor.dev/gvisor/pkg/log" - "gvisor.dev/gvisor/pkg/tcpip" - "gvisor.dev/gvisor/pkg/tcpip/buffer" - "gvisor.dev/gvisor/pkg/tcpip/header" - "gvisor.dev/gvisor/pkg/tcpip/link/sharedmem/queue" - "gvisor.dev/gvisor/pkg/tcpip/stack" -) - -// QueueConfig holds all the file descriptors needed to describe a tx or rx -// queue over shared memory. It is used when creating new shared memory -// endpoints to describe tx and rx queues. -type QueueConfig struct { - // DataFD is a file descriptor for the file that contains the data to - // be transmitted via this queue. Descriptors contain offsets within - // this file. - DataFD int - - // EventFD is a file descriptor for the event that is signaled when - // data is becomes available in this queue. - EventFD int - - // TxPipeFD is a file descriptor for the tx pipe associated with the - // queue. - TxPipeFD int - - // RxPipeFD is a file descriptor for the rx pipe associated with the - // queue. - RxPipeFD int - - // SharedDataFD is a file descriptor for the file that contains shared - // state between the two ends of the queue. This data specifies, for - // example, whether EventFD signaling is enabled or disabled. - SharedDataFD int -} - -type endpoint struct { - // mtu (maximum transmission unit) is the maximum size of a packet. - mtu uint32 - - // bufferSize is the size of each individual buffer. - bufferSize uint32 - - // addr is the local address of this endpoint. - addr tcpip.LinkAddress - - // rx is the receive queue. - rx rx - - // stopRequested is to be accessed atomically only, and determines if - // the worker goroutines should stop. - stopRequested uint32 - - // Wait group used to indicate that all workers have stopped. - completed sync.WaitGroup - - // mu protects the following fields. - mu sync.Mutex - - // tx is the transmit queue. - tx tx - - // workerStarted specifies whether the worker goroutine was started. - workerStarted bool -} - -// New creates a new shared-memory-based endpoint. Buffers will be broken up -// into buffers of "bufferSize" bytes. -func New(mtu, bufferSize uint32, addr tcpip.LinkAddress, tx, rx QueueConfig) (stack.LinkEndpoint, error) { - e := &endpoint{ - mtu: mtu, - bufferSize: bufferSize, - addr: addr, - } - - if err := e.tx.init(bufferSize, &tx); err != nil { - return nil, err - } - - if err := e.rx.init(bufferSize, &rx); err != nil { - e.tx.cleanup() - return nil, err - } - - return e, nil -} - -// Close frees all resources associated with the endpoint. -func (e *endpoint) Close() { - // Tell dispatch goroutine to stop, then write to the eventfd so that - // it wakes up in case it's sleeping. - atomic.StoreUint32(&e.stopRequested, 1) - syscall.Write(e.rx.eventFD, []byte{1, 0, 0, 0, 0, 0, 0, 0}) - - // Cleanup the queues inline if the worker hasn't started yet; we also - // know it won't start from now on because stopRequested is set to 1. - e.mu.Lock() - workerPresent := e.workerStarted - e.mu.Unlock() - - if !workerPresent { - e.tx.cleanup() - e.rx.cleanup() - } -} - -// Wait waits until all workers have stopped after a Close() call. -func (e *endpoint) Wait() { - e.completed.Wait() -} - -// Attach implements stack.LinkEndpoint.Attach. It launches the goroutine that -// reads packets from the rx queue. -func (e *endpoint) Attach(dispatcher stack.NetworkDispatcher) { - e.mu.Lock() - if !e.workerStarted && atomic.LoadUint32(&e.stopRequested) == 0 { - e.workerStarted = true - e.completed.Add(1) - // Link endpoints are not savable. When transportation endpoints - // are saved, they stop sending outgoing packets and all - // incoming packets are rejected. - go e.dispatchLoop(dispatcher) // S/R-SAFE: see above. - } - e.mu.Unlock() -} - -// IsAttached implements stack.LinkEndpoint.IsAttached. -func (e *endpoint) IsAttached() bool { - e.mu.Lock() - defer e.mu.Unlock() - return e.workerStarted -} - -// MTU implements stack.LinkEndpoint.MTU. It returns the value initialized -// during construction. -func (e *endpoint) MTU() uint32 { - return e.mtu - header.EthernetMinimumSize -} - -// Capabilities implements stack.LinkEndpoint.Capabilities. -func (*endpoint) Capabilities() stack.LinkEndpointCapabilities { - return 0 -} - -// MaxHeaderLength implements stack.LinkEndpoint.MaxHeaderLength. It returns the -// ethernet frame header size. -func (*endpoint) MaxHeaderLength() uint16 { - return header.EthernetMinimumSize -} - -// LinkAddress implements stack.LinkEndpoint.LinkAddress. It returns the local -// link address. -func (e *endpoint) LinkAddress() tcpip.LinkAddress { - return e.addr -} - -// WritePacket writes outbound packets to the file descriptor. If it is not -// currently writable, the packet is dropped. -func (e *endpoint) WritePacket(r *stack.Route, _ *stack.GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) *tcpip.Error { - // Add the ethernet header here. - eth := header.Ethernet(hdr.Prepend(header.EthernetMinimumSize)) - ethHdr := &header.EthernetFields{ - DstAddr: r.RemoteLinkAddress, - Type: protocol, - } - if r.LocalLinkAddress != "" { - ethHdr.SrcAddr = r.LocalLinkAddress - } else { - ethHdr.SrcAddr = e.addr - } - eth.Encode(ethHdr) - - v := payload.ToView() - // Transmit the packet. - e.mu.Lock() - ok := e.tx.transmit(hdr.View(), v) - e.mu.Unlock() - - if !ok { - return tcpip.ErrWouldBlock - } - - return nil -} - -// dispatchLoop reads packets from the rx queue in a loop and dispatches them -// to the network stack. -func (e *endpoint) dispatchLoop(d stack.NetworkDispatcher) { - // Post initial set of buffers. - limit := e.rx.q.PostedBuffersLimit() - if l := uint64(len(e.rx.data)) / uint64(e.bufferSize); limit > l { - limit = l - } - for i := uint64(0); i < limit; i++ { - b := queue.RxBuffer{ - Offset: i * uint64(e.bufferSize), - Size: e.bufferSize, - ID: i, - } - if !e.rx.q.PostBuffers([]queue.RxBuffer{b}) { - log.Warningf("Unable to post %v-th buffer", i) - } - } - - // Read in a loop until a stop is requested. - var rxb []queue.RxBuffer - for atomic.LoadUint32(&e.stopRequested) == 0 { - var n uint32 - rxb, n = e.rx.postAndReceive(rxb, &e.stopRequested) - - // Copy data from the shared area to its own buffer, then - // prepare to repost the buffer. - b := make([]byte, n) - offset := uint32(0) - for i := range rxb { - copy(b[offset:], e.rx.data[rxb[i].Offset:][:rxb[i].Size]) - offset += rxb[i].Size - - rxb[i].Size = e.bufferSize - } - - if n < header.EthernetMinimumSize { - continue - } - - // Send packet up the stack. - eth := header.Ethernet(b) - d.DeliverNetworkPacket(e, eth.SourceAddress(), eth.DestinationAddress(), eth.Type(), buffer.View(b[header.EthernetMinimumSize:]).ToVectorisedView()) - } - - // Clean state. - e.tx.cleanup() - e.rx.cleanup() - - e.completed.Done() -} |