diff options
Diffstat (limited to 'pkg/tcpip/transport/tcp/endpoint.go')
| -rw-r--r-- | pkg/tcpip/transport/tcp/endpoint.go | 501 |
1 files changed, 308 insertions, 193 deletions
diff --git a/pkg/tcpip/transport/tcp/endpoint.go b/pkg/tcpip/transport/tcp/endpoint.go index fe629aa40..4797f11d1 100644 --- a/pkg/tcpip/transport/tcp/endpoint.go +++ b/pkg/tcpip/transport/tcp/endpoint.go @@ -19,12 +19,12 @@ import ( "fmt" "math" "strings" - "sync" "sync/atomic" "time" "gvisor.dev/gvisor/pkg/rand" "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/hash/jenkins" @@ -120,6 +120,7 @@ const ( notifyMTUChanged notifyDrain notifyReset + notifyResetByPeer notifyKeepaliveChanged notifyMSSChanged // notifyTickleWorker is used to tickle the protocol main loop during a @@ -127,6 +128,7 @@ const ( // ensures the loop terminates if the final state of the endpoint is // say TIME_WAIT. notifyTickleWorker + notifyError ) // SACKInfo holds TCP SACK related information for a given endpoint. @@ -283,6 +285,18 @@ func (*EndpointInfo) IsEndpointInfo() {} type endpoint struct { EndpointInfo + // endpointEntry is used to queue endpoints for processing to the + // a given tcp processor goroutine. + // + // Precondition: epQueue.mu must be held to read/write this field.. + endpointEntry `state:"nosave"` + + // pendingProcessing is true if this endpoint is queued for processing + // to a TCP processor. + // + // Precondition: epQueue.mu must be held to read/write this field.. + pendingProcessing bool `state:"nosave"` + // workMu is used to arbitrate which goroutine may perform protocol // work. Only the main protocol goroutine is expected to call Lock() on // it, but other goroutines (e.g., send) may call TryLock() to eagerly @@ -324,6 +338,7 @@ type endpoint struct { // The following fields are protected by the mutex. mu sync.RWMutex `state:"nosave"` + // state must be read/set using the EndpointState()/setEndpointState() methods. state EndpointState `state:".(EndpointState)"` // origEndpointState is only used during a restore phase to save the @@ -359,7 +374,7 @@ type endpoint struct { workerRunning bool // workerCleanup specifies if the worker goroutine must perform cleanup - // before exitting. This can only be set to true when workerRunning is + // before exiting. This can only be set to true when workerRunning is // also true, and they're both protected by the mutex. workerCleanup bool @@ -371,6 +386,8 @@ type endpoint struct { // recentTS is the timestamp that should be sent in the TSEcr field of // the timestamp for future segments sent by the endpoint. This field is // updated if required when a new segment is received by this endpoint. + // + // recentTS must be read/written atomically. recentTS uint32 // tsOffset is a randomized offset added to the value of the @@ -567,6 +584,47 @@ func (e *endpoint) ResumeWork() { e.workMu.Unlock() } +// setEndpointState updates the state of the endpoint to state atomically. This +// method is unexported as the only place we should update the state is in this +// package but we allow the state to be read freely without holding e.mu. +// +// Precondition: e.mu must be held to call this method. +func (e *endpoint) setEndpointState(state EndpointState) { + oldstate := EndpointState(atomic.LoadUint32((*uint32)(&e.state))) + switch state { + case StateEstablished: + e.stack.Stats().TCP.CurrentEstablished.Increment() + case StateError: + fallthrough + case StateClose: + if oldstate == StateCloseWait || oldstate == StateEstablished { + e.stack.Stats().TCP.EstablishedResets.Increment() + } + fallthrough + default: + if oldstate == StateEstablished { + e.stack.Stats().TCP.CurrentEstablished.Decrement() + } + } + atomic.StoreUint32((*uint32)(&e.state), uint32(state)) +} + +// EndpointState returns the current state of the endpoint. +func (e *endpoint) EndpointState() EndpointState { + return EndpointState(atomic.LoadUint32((*uint32)(&e.state))) +} + +// setRecentTimestamp atomically sets the recentTS field to the +// provided value. +func (e *endpoint) setRecentTimestamp(recentTS uint32) { + atomic.StoreUint32(&e.recentTS, recentTS) +} + +// recentTimestamp atomically reads and returns the value of the recentTS field. +func (e *endpoint) recentTimestamp() uint32 { + return atomic.LoadUint32(&e.recentTS) +} + // keepalive is a synchronization wrapper used to appease stateify. See the // comment in endpoint, where it is used. // @@ -656,7 +714,7 @@ func (e *endpoint) Readiness(mask waiter.EventMask) waiter.EventMask { e.mu.RLock() defer e.mu.RUnlock() - switch e.state { + switch e.EndpointState() { case StateInitial, StateBound, StateConnecting, StateSynSent, StateSynRecv: // Ready for nothing. @@ -672,7 +730,7 @@ func (e *endpoint) Readiness(mask waiter.EventMask) waiter.EventMask { } } } - if e.state.connected() { + if e.EndpointState().connected() { // Determine if the endpoint is writable if requested. if (mask & waiter.EventOut) != 0 { e.sndBufMu.Lock() @@ -733,14 +791,20 @@ func (e *endpoint) Close() { // Issue a shutdown so that the peer knows we won't send any more data // if we're connected, or stop accepting if we're listening. e.Shutdown(tcpip.ShutdownWrite | tcpip.ShutdownRead) + e.closeNoShutdown() +} +// closeNoShutdown closes the endpoint without doing a full shutdown. This is +// used when a connection needs to be aborted with a RST and we want to skip +// a full 4 way TCP shutdown. +func (e *endpoint) closeNoShutdown() { e.mu.Lock() // For listening sockets, we always release ports inline so that they // are immediately available for reuse after Close() is called. If also // registered, we unregister as well otherwise the next user would fail // in Listen() when trying to register. - if e.state == StateListen && e.isPortReserved { + if e.EndpointState() == StateListen && e.isPortReserved { if e.isRegistered { e.stack.StartTransportEndpointCleanup(e.boundNICID, e.effectiveNetProtos, ProtocolNumber, e.ID, e, e.boundBindToDevice) e.isRegistered = false @@ -780,6 +844,8 @@ func (e *endpoint) closePendingAcceptableConnectionsLocked() { defer close(done) for n := range e.acceptedChan { n.notifyProtocolGoroutine(notifyReset) + // close all connections that have completed but + // not accepted by the application. n.Close() } }() @@ -797,11 +863,13 @@ func (e *endpoint) closePendingAcceptableConnectionsLocked() { // after Close() is called and the worker goroutine (if any) is done with its // work. func (e *endpoint) cleanupLocked() { + // Close all endpoints that might have been accepted by TCP but not by // the client. if e.acceptedChan != nil { e.closePendingAcceptableConnectionsLocked() } + e.workerCleanup = false if e.isRegistered { @@ -885,8 +953,14 @@ func (e *endpoint) ModerateRecvBuf(copied int) { // reject valid data that might already be in flight as the // acceptable window will shrink. if rcvWnd > e.rcvBufSize { + availBefore := e.receiveBufferAvailableLocked() e.rcvBufSize = rcvWnd - e.notifyProtocolGoroutine(notifyReceiveWindowChanged) + availAfter := e.receiveBufferAvailableLocked() + mask := uint32(notifyReceiveWindowChanged) + if crossed, above := e.windowCrossedACKThreshold(availAfter - availBefore); crossed && above { + mask |= notifyNonZeroReceiveWindow + } + e.notifyProtocolGoroutine(mask) } // We only update prevCopied when we grow the buffer because in cases @@ -914,7 +988,7 @@ func (e *endpoint) Read(*tcpip.FullAddress) (buffer.View, tcpip.ControlMessages, // reads to proceed before returning a ECONNRESET. e.rcvListMu.Lock() bufUsed := e.rcvBufUsed - if s := e.state; !s.connected() && s != StateClose && bufUsed == 0 { + if s := e.EndpointState(); !s.connected() && s != StateClose && bufUsed == 0 { e.rcvListMu.Unlock() he := e.HardError e.mu.RUnlock() @@ -938,7 +1012,7 @@ func (e *endpoint) Read(*tcpip.FullAddress) (buffer.View, tcpip.ControlMessages, func (e *endpoint) readLocked() (buffer.View, *tcpip.Error) { if e.rcvBufUsed == 0 { - if e.rcvClosed || !e.state.connected() { + if e.rcvClosed || !e.EndpointState().connected() { return buffer.View{}, tcpip.ErrClosedForReceive } return buffer.View{}, tcpip.ErrWouldBlock @@ -955,11 +1029,12 @@ func (e *endpoint) readLocked() (buffer.View, *tcpip.Error) { } e.rcvBufUsed -= len(v) - // If the window was zero before this read and if the read freed up - // enough buffer space for the scaled window to be non-zero then notify - // the protocol goroutine to send a window update. - if e.zeroWindow && !e.zeroReceiveWindow(e.rcv.rcvWndScale) { - e.zeroWindow = false + + // If the window was small before this read and if the read freed up + // enough buffer space, to either fit an aMSS or half a receive buffer + // (whichever smaller), then notify the protocol goroutine to send a + // window update. + if crossed, above := e.windowCrossedACKThreshold(len(v)); crossed && above { e.notifyProtocolGoroutine(notifyNonZeroReceiveWindow) } @@ -973,8 +1048,8 @@ func (e *endpoint) readLocked() (buffer.View, *tcpip.Error) { // Caller must hold e.mu and e.sndBufMu func (e *endpoint) isEndpointWritableLocked() (int, *tcpip.Error) { // The endpoint cannot be written to if it's not connected. - if !e.state.connected() { - switch e.state { + if !e.EndpointState().connected() { + switch e.EndpointState() { case StateError: return 0, e.HardError default: @@ -1032,42 +1107,86 @@ func (e *endpoint) Write(p tcpip.Payloader, opts tcpip.WriteOptions) (int64, <-c return 0, nil, perr } - if !opts.Atomic { // See above. - e.mu.RLock() - e.sndBufMu.Lock() + if opts.Atomic { + // Add data to the send queue. + s := newSegmentFromView(&e.route, e.ID, v) + e.sndBufUsed += len(v) + e.sndBufInQueue += seqnum.Size(len(v)) + e.sndQueue.PushBack(s) + e.sndBufMu.Unlock() + // Release the endpoint lock to prevent deadlocks due to lock + // order inversion when acquiring workMu. + e.mu.RUnlock() + } - // Because we released the lock before copying, check state again - // to make sure the endpoint is still in a valid state for a write. - avail, err = e.isEndpointWritableLocked() - if err != nil { + if e.workMu.TryLock() { + // Since we released locks in between it's possible that the + // endpoint transitioned to a CLOSED/ERROR states so make + // sure endpoint is still writable before trying to write. + if !opts.Atomic { // See above. + e.mu.RLock() + e.sndBufMu.Lock() + + // Because we released the lock before copying, check state again + // to make sure the endpoint is still in a valid state for a write. + avail, err = e.isEndpointWritableLocked() + if err != nil { + e.sndBufMu.Unlock() + e.mu.RUnlock() + e.stats.WriteErrors.WriteClosed.Increment() + return 0, nil, err + } + + // Discard any excess data copied in due to avail being reduced due + // to a simultaneous write call to the socket. + if avail < len(v) { + v = v[:avail] + } + // Add data to the send queue. + s := newSegmentFromView(&e.route, e.ID, v) + e.sndBufUsed += len(v) + e.sndBufInQueue += seqnum.Size(len(v)) + e.sndQueue.PushBack(s) e.sndBufMu.Unlock() + // Release the endpoint lock to prevent deadlocks due to lock + // order inversion when acquiring workMu. e.mu.RUnlock() - e.stats.WriteErrors.WriteClosed.Increment() - return 0, nil, err - } - // Discard any excess data copied in due to avail being reduced due - // to a simultaneous write call to the socket. - if avail < len(v) { - v = v[:avail] } - } - - // Add data to the send queue. - s := newSegmentFromView(&e.route, e.ID, v) - e.sndBufUsed += len(v) - e.sndBufInQueue += seqnum.Size(len(v)) - e.sndQueue.PushBack(s) - e.sndBufMu.Unlock() - // Release the endpoint lock to prevent deadlocks due to lock - // order inversion when acquiring workMu. - e.mu.RUnlock() - - if e.workMu.TryLock() { // Do the work inline. e.handleWrite() e.workMu.Unlock() } else { + if !opts.Atomic { // See above. + e.mu.RLock() + e.sndBufMu.Lock() + + // Because we released the lock before copying, check state again + // to make sure the endpoint is still in a valid state for a write. + avail, err = e.isEndpointWritableLocked() + if err != nil { + e.sndBufMu.Unlock() + e.mu.RUnlock() + e.stats.WriteErrors.WriteClosed.Increment() + return 0, nil, err + } + + // Discard any excess data copied in due to avail being reduced due + // to a simultaneous write call to the socket. + if avail < len(v) { + v = v[:avail] + } + // Add data to the send queue. + s := newSegmentFromView(&e.route, e.ID, v) + e.sndBufUsed += len(v) + e.sndBufInQueue += seqnum.Size(len(v)) + e.sndQueue.PushBack(s) + e.sndBufMu.Unlock() + // Release the endpoint lock to prevent deadlocks due to lock + // order inversion when acquiring workMu. + e.mu.RUnlock() + + } // Let the protocol goroutine do the work. e.sndWaker.Assert() } @@ -1084,7 +1203,7 @@ func (e *endpoint) Peek(vec [][]byte) (int64, tcpip.ControlMessages, *tcpip.Erro // The endpoint can be read if it's connected, or if it's already closed // but has some pending unread data. - if s := e.state; !s.connected() && s != StateClose { + if s := e.EndpointState(); !s.connected() && s != StateClose { if s == StateError { return 0, tcpip.ControlMessages{}, e.HardError } @@ -1096,7 +1215,7 @@ func (e *endpoint) Peek(vec [][]byte) (int64, tcpip.ControlMessages, *tcpip.Erro defer e.rcvListMu.Unlock() if e.rcvBufUsed == 0 { - if e.rcvClosed || !e.state.connected() { + if e.rcvClosed || !e.EndpointState().connected() { e.stats.ReadErrors.ReadClosed.Increment() return 0, tcpip.ControlMessages{}, tcpip.ErrClosedForReceive } @@ -1133,20 +1252,65 @@ func (e *endpoint) Peek(vec [][]byte) (int64, tcpip.ControlMessages, *tcpip.Erro return num, tcpip.ControlMessages{}, nil } -// zeroReceiveWindow checks if the receive window to be announced now would be -// zero, based on the amount of available buffer and the receive window scaling. +// windowCrossedACKThreshold checks if the receive window to be announced now +// would be under aMSS or under half receive buffer, whichever smaller. This is +// useful as a receive side silly window syndrome prevention mechanism. If +// window grows to reasonable value, we should send ACK to the sender to inform +// the rx space is now large. We also want ensure a series of small read()'s +// won't trigger a flood of spurious tiny ACK's. // -// It must be called with rcvListMu held. -func (e *endpoint) zeroReceiveWindow(scale uint8) bool { - if e.rcvBufUsed >= e.rcvBufSize { - return true +// For large receive buffers, the threshold is aMSS - once reader reads more +// than aMSS we'll send ACK. For tiny receive buffers, the threshold is half of +// receive buffer size. This is chosen arbitrairly. +// crossed will be true if the window size crossed the ACK threshold. +// above will be true if the new window is >= ACK threshold and false +// otherwise. +func (e *endpoint) windowCrossedACKThreshold(deltaBefore int) (crossed bool, above bool) { + newAvail := e.receiveBufferAvailableLocked() + oldAvail := newAvail - deltaBefore + if oldAvail < 0 { + oldAvail = 0 + } + + threshold := int(e.amss) + if threshold > e.rcvBufSize/2 { + threshold = e.rcvBufSize / 2 + } + + switch { + case oldAvail < threshold && newAvail >= threshold: + return true, true + case oldAvail >= threshold && newAvail < threshold: + return true, false } + return false, false +} + +// SetSockOptBool sets a socket option. +func (e *endpoint) SetSockOptBool(opt tcpip.SockOptBool, v bool) *tcpip.Error { + switch opt { + case tcpip.V6OnlyOption: + // We only recognize this option on v6 endpoints. + if e.NetProto != header.IPv6ProtocolNumber { + return tcpip.ErrInvalidEndpointState + } + + e.mu.Lock() + defer e.mu.Unlock() - return ((e.rcvBufSize - e.rcvBufUsed) >> scale) == 0 + // We only allow this to be set when we're in the initial state. + if e.EndpointState() != StateInitial { + return tcpip.ErrInvalidEndpointState + } + + e.v6only = v + } + + return nil } // SetSockOptInt sets a socket option. -func (e *endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error { +func (e *endpoint) SetSockOptInt(opt tcpip.SockOptInt, v int) *tcpip.Error { switch opt { case tcpip.ReceiveBufferSizeOption: // Make sure the receive buffer size is within the min and max @@ -1181,10 +1345,16 @@ func (e *endpoint) SetSockOptInt(opt tcpip.SockOpt, v int) *tcpip.Error { size = math.MaxInt32 / 2 } + availBefore := e.receiveBufferAvailableLocked() e.rcvBufSize = size + availAfter := e.receiveBufferAvailableLocked() + e.rcvAutoParams.disabled = true - if e.zeroWindow && !e.zeroReceiveWindow(scale) { - e.zeroWindow = false + + // Immediately send an ACK to uncork the sender silly window + // syndrome prevetion, when our available space grows above aMSS + // or half receive buffer, whichever smaller. + if crossed, above := e.windowCrossedACKThreshold(availAfter - availBefore); crossed && above { mask |= notifyNonZeroReceiveWindow } e.rcvListMu.Unlock() @@ -1256,19 +1426,14 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error { return nil case tcpip.BindToDeviceOption: - e.mu.Lock() - defer e.mu.Unlock() - if v == "" { - e.bindToDevice = 0 - return nil - } - for nicID, nic := range e.stack.NICInfo() { - if nic.Name == string(v) { - e.bindToDevice = nicID - return nil - } + id := tcpip.NICID(v) + if id != 0 && !e.stack.HasNIC(id) { + return tcpip.ErrUnknownDevice } - return tcpip.ErrUnknownDevice + e.mu.Lock() + e.bindToDevice = id + e.mu.Unlock() + return nil case tcpip.QuickAckOption: if v == 0 { @@ -1289,23 +1454,6 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error { e.notifyProtocolGoroutine(notifyMSSChanged) return nil - case tcpip.V6OnlyOption: - // We only recognize this option on v6 endpoints. - if e.NetProto != header.IPv6ProtocolNumber { - return tcpip.ErrInvalidEndpointState - } - - e.mu.Lock() - defer e.mu.Unlock() - - // We only allow this to be set when we're in the initial state. - if e.state != StateInitial { - return tcpip.ErrInvalidEndpointState - } - - e.v6only = v != 0 - return nil - case tcpip.TTLOption: e.mu.Lock() e.ttl = uint8(v) @@ -1366,14 +1514,14 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error { // Acquire the work mutex as we may need to // reinitialize the congestion control state. e.mu.Lock() - state := e.state + state := e.EndpointState() e.cc = v e.mu.Unlock() switch state { case StateEstablished: e.workMu.Lock() e.mu.Lock() - if e.state == state { + if e.EndpointState() == state { e.snd.cc = e.snd.initCongestionControl(e.cc) } e.mu.Unlock() @@ -1436,7 +1584,7 @@ func (e *endpoint) readyReceiveSize() (int, *tcpip.Error) { defer e.mu.RUnlock() // The endpoint cannot be in listen state. - if e.state == StateListen { + if e.EndpointState() == StateListen { return 0, tcpip.ErrInvalidEndpointState } @@ -1446,8 +1594,27 @@ func (e *endpoint) readyReceiveSize() (int, *tcpip.Error) { return e.rcvBufUsed, nil } +// GetSockOptBool implements tcpip.Endpoint.GetSockOptBool. +func (e *endpoint) GetSockOptBool(opt tcpip.SockOptBool) (bool, *tcpip.Error) { + switch opt { + case tcpip.V6OnlyOption: + // We only recognize this option on v6 endpoints. + if e.NetProto != header.IPv6ProtocolNumber { + return false, tcpip.ErrUnknownProtocolOption + } + + e.mu.Lock() + v := e.v6only + e.mu.Unlock() + + return v, nil + } + + return false, tcpip.ErrUnknownProtocolOption +} + // GetSockOptInt implements tcpip.Endpoint.GetSockOptInt. -func (e *endpoint) GetSockOptInt(opt tcpip.SockOpt) (int, *tcpip.Error) { +func (e *endpoint) GetSockOptInt(opt tcpip.SockOptInt) (int, *tcpip.Error) { switch opt { case tcpip.ReceiveQueueSizeOption: return e.readyReceiveSize() @@ -1525,12 +1692,8 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error { case *tcpip.BindToDeviceOption: e.mu.RLock() - defer e.mu.RUnlock() - if nic, ok := e.stack.NICInfo()[e.bindToDevice]; ok { - *o = tcpip.BindToDeviceOption(nic.Name) - return nil - } - *o = "" + *o = tcpip.BindToDeviceOption(e.bindToDevice) + e.mu.RUnlock() return nil case *tcpip.QuickAckOption: @@ -1540,22 +1703,6 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error { } return nil - case *tcpip.V6OnlyOption: - // We only recognize this option on v6 endpoints. - if e.NetProto != header.IPv6ProtocolNumber { - return tcpip.ErrUnknownProtocolOption - } - - e.mu.Lock() - v := e.v6only - e.mu.Unlock() - - *o = 0 - if v { - *o = 1 - } - return nil - case *tcpip.TTLOption: e.mu.Lock() *o = tcpip.TTLOption(e.ttl) @@ -1656,26 +1803,11 @@ func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error { } func (e *endpoint) checkV4Mapped(addr *tcpip.FullAddress) (tcpip.NetworkProtocolNumber, *tcpip.Error) { - netProto := e.NetProto - if header.IsV4MappedAddress(addr.Addr) { - // Fail if using a v4 mapped address on a v6only endpoint. - if e.v6only { - return 0, tcpip.ErrNoRoute - } - - netProto = header.IPv4ProtocolNumber - addr.Addr = addr.Addr[header.IPv6AddressSize-header.IPv4AddressSize:] - if addr.Addr == header.IPv4Any { - addr.Addr = "" - } - } - - // Fail if we're bound to an address length different from the one we're - // checking. - if l := len(e.ID.LocalAddress); l != 0 && len(addr.Addr) != 0 && l != len(addr.Addr) { - return 0, tcpip.ErrInvalidEndpointState + unwrapped, netProto, err := e.TransportEndpointInfo.AddrNetProto(*addr, e.v6only) + if err != nil { + return 0, err } - + *addr = unwrapped return netProto, nil } @@ -1711,7 +1843,7 @@ func (e *endpoint) connect(addr tcpip.FullAddress, handshake bool, run bool) *tc return err } - if e.state.connected() { + if e.EndpointState().connected() { // The endpoint is already connected. If caller hasn't been // notified yet, return success. if !e.isConnectNotified { @@ -1723,7 +1855,7 @@ func (e *endpoint) connect(addr tcpip.FullAddress, handshake bool, run bool) *tc } nicID := addr.NIC - switch e.state { + switch e.EndpointState() { case StateBound: // If we're already bound to a NIC but the caller is requesting // that we use a different one now, we cannot proceed. @@ -1830,7 +1962,7 @@ func (e *endpoint) connect(addr tcpip.FullAddress, handshake bool, run bool) *tc } e.isRegistered = true - e.state = StateConnecting + e.setEndpointState(StateConnecting) e.route = r.Clone() e.boundNICID = nicID e.effectiveNetProtos = netProtos @@ -1851,14 +1983,13 @@ func (e *endpoint) connect(addr tcpip.FullAddress, handshake bool, run bool) *tc } e.segmentQueue.mu.Unlock() e.snd.updateMaxPayloadSize(int(e.route.MTU()), 0) - e.state = StateEstablished - e.stack.Stats().TCP.CurrentEstablished.Increment() + e.setEndpointState(StateEstablished) } if run { e.workerRunning = true e.stack.Stats().TCP.ActiveConnectionOpenings.Increment() - go e.protocolMainLoop(handshake) // S/R-SAFE: will be drained before save. + go e.protocolMainLoop(handshake, nil) // S/R-SAFE: will be drained before save. } return tcpip.ErrConnectStarted @@ -1876,7 +2007,7 @@ func (e *endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error { e.shutdownFlags |= flags finQueued := false switch { - case e.state.connected(): + case e.EndpointState().connected(): // Close for read. if (e.shutdownFlags & tcpip.ShutdownRead) != 0 { // Mark read side as closed. @@ -1888,8 +2019,18 @@ func (e *endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error { // If we're fully closed and we have unread data we need to abort // the connection with a RST. if (e.shutdownFlags&tcpip.ShutdownWrite) != 0 && rcvBufUsed > 0 { - e.notifyProtocolGoroutine(notifyReset) e.mu.Unlock() + // Try to send an active reset immediately if the + // work mutex is available. + if e.workMu.TryLock() { + e.mu.Lock() + e.resetConnectionLocked(tcpip.ErrConnectionAborted) + e.notifyProtocolGoroutine(notifyTickleWorker) + e.mu.Unlock() + e.workMu.Unlock() + } else { + e.notifyProtocolGoroutine(notifyReset) + } return nil } } @@ -1911,11 +2052,10 @@ func (e *endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error { finQueued = true // Mark endpoint as closed. e.sndClosed = true - e.sndBufMu.Unlock() } - case e.state == StateListen: + case e.EndpointState() == StateListen: // Tell protocolListenLoop to stop. if flags&tcpip.ShutdownRead != 0 { e.notifyProtocolGoroutine(notifyClose) @@ -1956,7 +2096,7 @@ func (e *endpoint) listen(backlog int) *tcpip.Error { // When the endpoint shuts down, it sets workerCleanup to true, and from // that point onward, acceptedChan is the responsibility of the cleanup() // method (and should not be touched anywhere else, including here). - if e.state == StateListen && !e.workerCleanup { + if e.EndpointState() == StateListen && !e.workerCleanup { // Adjust the size of the channel iff we can fix existing // pending connections into the new one. if len(e.acceptedChan) > backlog { @@ -1974,7 +2114,7 @@ func (e *endpoint) listen(backlog int) *tcpip.Error { return nil } - if e.state == StateInitial { + if e.EndpointState() == StateInitial { // The listen is called on an unbound socket, the socket is // automatically bound to a random free port with the local // address set to INADDR_ANY. @@ -1984,7 +2124,7 @@ func (e *endpoint) listen(backlog int) *tcpip.Error { } // Endpoint must be bound before it can transition to listen mode. - if e.state != StateBound { + if e.EndpointState() != StateBound { e.stats.ReadErrors.InvalidEndpointState.Increment() return tcpip.ErrInvalidEndpointState } @@ -1995,24 +2135,27 @@ func (e *endpoint) listen(backlog int) *tcpip.Error { } e.isRegistered = true - e.state = StateListen + e.setEndpointState(StateListen) + if e.acceptedChan == nil { e.acceptedChan = make(chan *endpoint, backlog) } e.workerRunning = true - go e.protocolListenLoop( // S/R-SAFE: drained on save. seqnum.Size(e.receiveBufferAvailable())) - return nil } // startAcceptedLoop sets up required state and starts a goroutine with the // main loop for accepted connections. func (e *endpoint) startAcceptedLoop(waiterQueue *waiter.Queue) { + e.mu.Lock() e.waiterQueue = waiterQueue e.workerRunning = true - go e.protocolMainLoop(false) // S/R-SAFE: drained on save. + e.mu.Unlock() + wakerInitDone := make(chan struct{}) + go e.protocolMainLoop(false, wakerInitDone) // S/R-SAFE: drained on save. + <-wakerInitDone } // Accept returns a new endpoint if a peer has established a connection @@ -2022,7 +2165,7 @@ func (e *endpoint) Accept() (tcpip.Endpoint, *waiter.Queue, *tcpip.Error) { defer e.mu.RUnlock() // Endpoint must be in listen state before it can accept connections. - if e.state != StateListen { + if e.EndpointState() != StateListen { return nil, nil, tcpip.ErrInvalidEndpointState } @@ -2049,7 +2192,7 @@ func (e *endpoint) bindLocked(addr tcpip.FullAddress) (err *tcpip.Error) { // Don't allow binding once endpoint is not in the initial state // anymore. This is because once the endpoint goes into a connected or // listen state, it is already bound. - if e.state != StateInitial { + if e.EndpointState() != StateInitial { return tcpip.ErrAlreadyBound } @@ -2111,7 +2254,7 @@ func (e *endpoint) bindLocked(addr tcpip.FullAddress) (err *tcpip.Error) { } // Mark endpoint as bound. - e.state = StateBound + e.setEndpointState(StateBound) return nil } @@ -2133,7 +2276,7 @@ func (e *endpoint) GetRemoteAddress() (tcpip.FullAddress, *tcpip.Error) { e.mu.RLock() defer e.mu.RUnlock() - if !e.state.connected() { + if !e.EndpointState().connected() { return tcpip.FullAddress{}, tcpip.ErrNotConnected } @@ -2144,45 +2287,22 @@ func (e *endpoint) GetRemoteAddress() (tcpip.FullAddress, *tcpip.Error) { }, nil } -// HandlePacket is called by the stack when new packets arrive to this transport -// endpoint. func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, pkt tcpip.PacketBuffer) { - s := newSegment(r, id, pkt) - if !s.parse() { - e.stack.Stats().MalformedRcvdPackets.Increment() - e.stack.Stats().TCP.InvalidSegmentsReceived.Increment() - e.stats.ReceiveErrors.MalformedPacketsReceived.Increment() - s.decRef() - return - } - - if !s.csumValid { - e.stack.Stats().MalformedRcvdPackets.Increment() - e.stack.Stats().TCP.ChecksumErrors.Increment() - e.stats.ReceiveErrors.ChecksumErrors.Increment() - s.decRef() - return - } - - e.stack.Stats().TCP.ValidSegmentsReceived.Increment() - e.stats.SegmentsReceived.Increment() - if (s.flags & header.TCPFlagRst) != 0 { - e.stack.Stats().TCP.ResetsReceived.Increment() - } - - e.enqueueSegment(s) + // TCP HandlePacket is not required anymore as inbound packets first + // land at the Dispatcher which then can either delivery using the + // worker go routine or directly do the invoke the tcp processing inline + // based on the state of the endpoint. } -func (e *endpoint) enqueueSegment(s *segment) { +func (e *endpoint) enqueueSegment(s *segment) bool { // Send packet to worker goroutine. - if e.segmentQueue.enqueue(s) { - e.newSegmentWaker.Assert() - } else { + if !e.segmentQueue.enqueue(s) { // The queue is full, so we drop the segment. e.stack.Stats().DroppedPackets.Increment() e.stats.ReceiveErrors.SegmentQueueDropped.Increment() - s.decRef() + return false } + return true } // HandleControlPacket implements stack.TransportEndpoint.HandleControlPacket. @@ -2225,13 +2345,10 @@ func (e *endpoint) readyToRead(s *segment) { if s != nil { s.incRef() e.rcvBufUsed += s.data.Size() - // Check if the receive window is now closed. If so make sure - // we set the zero window before we deliver the segment to ensure - // that a subsequent read of the segment will correctly trigger - // a non-zero notification. - if avail := e.receiveBufferAvailableLocked(); avail>>e.rcv.rcvWndScale == 0 { + // Increase counter if the receive window falls down below MSS + // or half receive buffer size, whichever smaller. + if crossed, above := e.windowCrossedACKThreshold(-s.data.Size()); crossed && !above { e.stats.ReceiveErrors.ZeroRcvWindowState.Increment() - e.zeroWindow = true } e.rcvList.PushBack(s) } else { @@ -2302,8 +2419,8 @@ func (e *endpoint) rcvWndScaleForHandshake() int { // updateRecentTimestamp updates the recent timestamp using the algorithm // described in https://tools.ietf.org/html/rfc7323#section-4.3 func (e *endpoint) updateRecentTimestamp(tsVal uint32, maxSentAck seqnum.Value, segSeq seqnum.Value) { - if e.sendTSOk && seqnum.Value(e.recentTS).LessThan(seqnum.Value(tsVal)) && segSeq.LessThanEq(maxSentAck) { - e.recentTS = tsVal + if e.sendTSOk && seqnum.Value(e.recentTimestamp()).LessThan(seqnum.Value(tsVal)) && segSeq.LessThanEq(maxSentAck) { + e.setRecentTimestamp(tsVal) } } @@ -2313,7 +2430,7 @@ func (e *endpoint) updateRecentTimestamp(tsVal uint32, maxSentAck seqnum.Value, func (e *endpoint) maybeEnableTimestamp(synOpts *header.TCPSynOptions) { if synOpts.TS { e.sendTSOk = true - e.recentTS = synOpts.TSVal + e.setRecentTimestamp(synOpts.TSVal) } } @@ -2402,7 +2519,7 @@ func (e *endpoint) completeState() stack.TCPEndpointState { // Endpoint TCP Option state. s.SendTSOk = e.sendTSOk - s.RecentTS = e.recentTS + s.RecentTS = e.recentTimestamp() s.TSOffset = e.tsOffset s.SACKPermitted = e.sackPermitted s.SACK.Blocks = make([]header.SACKBlock, e.sack.NumBlocks) @@ -2509,9 +2626,7 @@ func (e *endpoint) initGSO() { // State implements tcpip.Endpoint.State. It exports the endpoint's protocol // state for diagnostics. func (e *endpoint) State() uint32 { - e.mu.Lock() - defer e.mu.Unlock() - return uint32(e.state) + return uint32(e.EndpointState()) } // Info returns a copy of the endpoint info. |