正常结束 RST情况没有处理

cmd/netstack/TcpConn.go

@@ -10,6 +10,7 @@ import (
 	"netstack/tcpip/stack"
 	"netstack/tcpip/transport/tcp"
 	"netstack/waiter"
+	"time"
 )
 
 // Dial 呼叫tcp服务端
@@ -36,6 +37,11 @@ func Dial(s *stack.Stack, proto tcpip.NetworkProtocolNumber, addr tcpip.Address,
 		}
 	}
 
+	ep.SetSockOpt(tcpip.KeepaliveEnabledOption(1))
+	ep.SetSockOpt(tcpip.KeepaliveIntervalOption(75 * time.Second))
+	ep.SetSockOpt(tcpip.KeepaliveIdleOption(30 * time.Second)) // 30s的探活心跳
+	ep.SetSockOpt(tcpip.KeepaliveCountOption(9))
+
 	return &TcpConn{
 		ep:       ep,
 		wq:       &wq,

cmd/netstack/main.go

@@ -147,23 +147,30 @@ func main() {
 			}
 			log.Println("服务端 建立连接")
 
-			go func() {
+			go func(*TcpConn) {
 				cnt := 0
-				time.Sleep(2 * time.Second)
+				time.Sleep(1 * time.Second)
 				for {
 					// 一个慢读者 才能体现出网络的情况
 					buf := make([]byte, 1024)
 					n, err := conn.Read(buf)
 					if err != nil {
-						log.Println(n, err)
+						// TODO 添加一个 error 表明无法继续读取 对端要求关闭
 						break
 					}
 					cnt+=n
 					logger.NOTICE("服务端读取了数据", fmt.Sprintf("n: %d, cnt: %d", n, cnt), string(buf))
-					//conn.Write([]byte("Hello Client"))
 				}
-			}()
+
+				// 我端收到了 fin 关闭读 继续写
+				conn.Write([]byte("Bye Client"))
+				// 我端向对端发一个终止报文
+				conn.ep.Close()
+				log.Println("服务端 结束读取")
+
+			}(conn)
 		}
+
 	}()
 
 	go func() {
@@ -174,31 +181,23 @@ func main() {
 		if err != nil {
 			log.Fatal(err)
 		}
-		log.Printf("客户端 建立连接\n")
 
-		conn.SetSockOpt(tcpip.KeepaliveEnabledOption(1))
-		conn.SetSockOpt(tcpip.KeepaliveIntervalOption(75 * time.Second))
-		conn.SetSockOpt(tcpip.KeepaliveIdleOption(30 * time.Second)) // 30s的探活心跳
-		conn.SetSockOpt(tcpip.KeepaliveCountOption(9))
+		log.Printf("客户端 建立连接\n\n客户端 写入数据\n")
 
-		log.Printf("\n\n客户端 写入数据")
-
-		cnt := 0
-		for i := 0; i < 20; i++ {
+		for i := 0; i < 3; i++ {
 			conn.Write(make([]byte, 1<<(5)))
-			cnt += 1<<(5)
-			//buf := make([]byte, 1024)
-			//n, err := conn.Read(buf)
-			//if err != nil {
-			//	log.Println(err)
-			//	break
-			//}
-			//logger.NOTICE(string(buf[:n]))
 		}
 
-		logger.NOTICE("写完了", fmt.Sprintf("共计写入: %d", cnt))
-
 		conn.Close()
+
+		buf := make([]byte, 1024)
+		n, err := conn.Read(buf)
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		logger.NOTICE(string(buf[:n]))
+
 	}()
 
 	//l, err := net.Listen("tcp", "127.0.0.1:9999")

tcpip/link/loopback/loopback.go

@@ -1,8 +1,6 @@
 package loopback
 
 import (
-	"fmt"
-	"netstack/logger"
 	"netstack/tcpip"
 	"netstack/tcpip/buffer"
 	"netstack/tcpip/stack"
@@ -51,10 +49,10 @@ func (e *endpoint) WritePacket(r *stack.Route, hdr buffer.Prependable, payload b
 	//time.Sleep(time.Duration(rand.Intn(50)+50) * time.Millisecond)
 
 	e.count++
-	if e.count == 6 { // 丢掉客户端写入的第二个包
-		logger.NOTICE(fmt.Sprintf("统计 %d  丢掉这个报文", e.count))
-		return nil
-	}
+	//if e.count == 6 { // 丢掉客户端写入的第二个包
+	//	logger.NOTICE(fmt.Sprintf("统计 %d  丢掉这个报文", e.count))
+	//	return nil
+	//}
 	// Because we're immediately turning around and writing the packet back to the
 	// rx path, we intentionally don't preserve the remote and local link
 	// addresses from the stack.Route we're passed.

tcpip/tcpip.go

@@ -7,6 +7,7 @@ import (
 	"netstack/waiter"
 	"reflect"
 	"strings"
+	"sync"
 	"sync/atomic"
 	"time"
 )
@@ -638,3 +639,36 @@ func (a Address) String() string {
 		return fmt.Sprintf("%s", string(a))
 	}
 }
+
+
+// danglingEndpointsMu protects access to danglingEndpoints.
+// 一个摇摆不定的端点 一个行将就木的端点
+var danglingEndpointsMu sync.Mutex
+
+// danglingEndpoints tracks all dangling endpoints no longer owned by the app.
+var danglingEndpoints = make(map[Endpoint]struct{})
+
+// GetDanglingEndpoints returns all dangling endpoints.
+func GetDanglingEndpoints() []Endpoint {
+	es := make([]Endpoint, 0, len(danglingEndpoints))
+	danglingEndpointsMu.Lock()
+	for e := range danglingEndpoints {
+		es = append(es, e)
+	}
+	danglingEndpointsMu.Unlock()
+	return es
+}
+
+// AddDanglingEndpoint adds a dangling endpoint.
+func AddDanglingEndpoint(e Endpoint) {
+	danglingEndpointsMu.Lock()
+	danglingEndpoints[e] = struct{}{}
+	danglingEndpointsMu.Unlock()
+}
+
+// DeleteDanglingEndpoint removes a dangling endpoint.
+func DeleteDanglingEndpoint(e Endpoint) {
+	danglingEndpointsMu.Lock()
+	delete(danglingEndpoints, e)
+	danglingEndpointsMu.Unlock()
+}

tcpip/transport/tcp/connect.go

@@ -172,12 +172,11 @@ func (h *handshake) resolveRoute() *tcpip.Error {
 			// Resolution not completed. Keep trying...
 
 		case wakerForNotification:
-			// TODO
-			//n := h.ep.fetchNotifications()
-			//if n&notifyClose != 0 {
-			//	h.ep.route.RemoveWaker(resolutionWaker)
-			//	return tcpip.ErrAborted
-			//}
+			n := h.ep.fetchNotifications()
+			if n&notifyClose != 0 {
+				h.ep.route.RemoveWaker(resolutionWaker)
+				return tcpip.ErrAborted
+			}
 			//if n&notifyDrain != 0 {
 			//	close(h.ep.drainDone)
 			//	<-h.ep.undrain
@@ -608,8 +607,8 @@ func sendTCP(r *stack.Route, id stack.TransportEndpointID, data buffer.Vectorise
 
 	logger.GetInstance().Info(logger.TCP, func() {
 	})
-	log.Printf("TCP 发送 [%s] 报文片段到 %s, seq: %d, ack: %d, 可接收rcvWnd: %d",
-		flagString(flags), fmt.Sprintf("%s:%d", id.RemoteAddress, id.RemotePort),
+	log.Printf("TCP :%d 发送 [%s] 报文片段到 %s, seq: %d, ack: %d, 可接收rcvWnd: %d",
+		id.LocalPort, flagString(flags), fmt.Sprintf("%s:%d", id.RemoteAddress, id.RemotePort),
 		seq, ack, rcvWnd)
 
 	return r.WritePacket(hdr, data, ProtocolNumber, ttl)
@@ -703,12 +702,32 @@ func (e *endpoint) handleClose() *tcpip.Error {
 	e.handleWrite()
 
 	// Mark send side as closed.
-	// 标记发送器关闭
+	// 标记发送器关闭 标记过之后 e.rcv.closed && e.snd.closed 主循环将会退出
 	e.snd.closed = true
 
 	return nil
 }
 
+func (e *endpoint) resetConnectionLocked(err *tcpip.Error) {
+	e.sendRaw(buffer.VectorisedView{}, flagRst|flagAck, e.snd.sndUna, e.rcv.rcvNxt, 0)
+	e.state = stateError
+	e.hardError = err
+}
+
+func (e *endpoint) completeWorkerLocked() {
+	e.workerRunning = false // 标记当前goroutine已经停运
+	if e.workerCleanup {
+		//if e.id.LocalPort != 9999 {
+		//	logger.NOTICE("客户端开始清理资源")
+		//	log.Println(e.snd.sndUna , e.snd.sndNxtList)
+		//} else {
+		//	logger.NOTICE("服务端开始清理资源")
+		//	log.Println(e.snd.sndUna , e.snd.sndNxtList)
+		//}
+		e.cleanupLocked()
+	}
+}
+
 // handleSegments 从队列中取出 tcp 段数据，然后处理它们。
 func (e *endpoint) handleSegments() *tcpip.Error {
 	checkRequeue := true
@@ -753,7 +772,7 @@ func (e *endpoint) handleSegments() *tcpip.Error {
 			// information."
 			// 处理tcp数据段，同时给接收器和发送器
 			// 为何要给发送器传接收到的数据段呢？主要是为了滑动窗口的滑动和拥塞控制处理
-			e.rcv.handleRcvdSegment(s)
+			e.rcv.handleRcvdSegment(s) // 在收到fin报文后 将不再接受任何报文
 			e.snd.handleRcvdSegment(s)
 		}
 		s.decRef() // 该segment处理完成
@@ -829,11 +848,22 @@ func (e *endpoint) disableKeepaliveTimer() {
 
 // protocolMainLoop 是TCP协议的主循环。它在自己的goroutine中运行，负责握手、发送段和处理收到的段
 func (e *endpoint) protocolMainLoop(handshake bool) *tcpip.Error {
+	var closeTimer *time.Timer
+	var closeWaker sleep.Waker
 
 	// 收尾工作
 	// 收尾的一些工作
 	epilogue := func() {
 		// e.mu is expected to be hold upon entering this section.
+		if e.snd != nil {
+			e.snd.resendTimer.cleanup() // 放弃所有重发报文
+		}
+
+		if closeTimer != nil {
+			closeTimer.Stop() // 正常结束 MainLoop
+		}
+
+		e.completeWorkerLocked()
 
 		// TODO 需要添加
 		e.mu.Unlock()
@@ -907,6 +937,12 @@ func (e *endpoint) protocolMainLoop(handshake bool) *tcpip.Error {
 			w: &e.newSegmentWaker,
 			f: e.handleSegments,
 		},
+		{
+			w: &closeWaker,
+			f: func() *tcpip.Error {
+				return tcpip.ErrConnectionAborted // 如果在3s内没有正常结束四次挥手 将强制结束连接
+			},
+		},
 		{
 			w: &e.snd.resendWaker,
 			f: func() *tcpip.Error {
@@ -939,12 +975,18 @@ func (e *endpoint) protocolMainLoop(handshake bool) *tcpip.Error {
 				}
 
 				if n&notifyReset != 0 {
-
+					e.mu.Lock()
+					e.resetConnectionLocked(tcpip.ErrConnectionAborted)
+					e.mu.Unlock()
 				}
 
-				//if n&notifyClose != 0 && closeTimer == nil {
-				//
-				//}
+				if n&notifyClose != 0 && closeTimer == nil {
+					// Reset the connection 3 seconds after the
+					// endpoint has been closed.
+					closeTimer = time.AfterFunc(3*time.Second, func() {
+						closeWaker.Assert()
+					})
+				}
 
 				if n&notifyDrain != 0 {
 				}
@@ -977,12 +1019,32 @@ func (e *endpoint) protocolMainLoop(handshake bool) *tcpip.Error {
 	}
 	e.rcvListMu.Unlock()
 
-	// TODO 需要添加 workerCleanup
+	e.mu.RLock()
+	if e.workerCleanup {
+		e.notifyProtocolGoroutine(notifyClose)
+	}
+	e.mu.RUnlock()
+
 
 	// 主循环，处理tcp报文
 	// 要使这个主循环结束，也就是tcp连接完全关闭，得同时满足三个条件：
 	// 1，接收器关闭了 2，发送器关闭了 3，下一个未确认的序列号等于添加到发送列表的下一个段的序列号
-	//for !e.rcv.closed || !e.snd.closed || e.snd.sndUna != e.snd.sndNxtList {
+	//
+	// 对于服务端而言:
+	//     1. 在收到 FIN 报文后 在handleSegment 中处理报文时 handleRcvSegment -> consumeSegment 将e.rcv.closed
+	//     2. 在用户层主动调用 Close 时 在Shutdown 中 唤醒 e.sndCloseWaker 执行 handleClose 将e.snd.closed
+	//     3. 在用户层主动调用 Close 后 将会发送给 客户端 一个 FIN 报文  当收到正确的客户端ack时
+	//        如果 e.snd.sndUna == e.snd.sndNxtList 也就是没有可以发送的数据了 服务端就可以退出了
+	//
+	// 对于客户端而言:
+	//     1. 应用层主动调用了 Close -> Shutdown 唤醒e.sndCloseWaker 执行 handleClose
+	//        将e.snd.closed snd设置close并不是关闭写  将会发送给 服务端 一个 FIN 报文  当收到正确的服务端端ack时 客户端不直接退出
+	//        而是等待服务端的后续数据 并且去回复对应的ack 但是服务端并不会去消费这些ack
+	//        NOTE 这里仅仅是不通知上层用户程序消费 底层的重发机制什么的都还在工作 因此仍然是可靠传输
+	//     2. 当客户端收到来自服务端的 FIN 报文的时候 在handleSegment 中处理报文时
+	//        handleRcvSegment -> consumeSegment 将e.rcv.closed
+	//     3. 在收完完 FIN 报文后 e.snd.sndUna == e.snd.sndNxtList 也就是没有可以发送的数据了 客户端就可以退出了
+	//
 	for !e.rcv.closed || !e.snd.closed || e.snd.sndUna != e.snd.sndNxtList {
 		e.workMu.Unlock()
 		// s.Fetch 会返回事件的index，比如 v=0 的话，
@@ -992,7 +1054,7 @@ func (e *endpoint) protocolMainLoop(handshake bool) *tcpip.Error {
 		e.workMu.Lock()
 		if err := funcs[v].f(); err != nil {
 			e.mu.Lock()
-			//e.resetConnectionLocked(err)
+			e.resetConnectionLocked(err)
 			// Lock released below.
 			epilogue()
 			log.Println(err)

tcpip/transport/tcp/endpoint.go

@@ -122,6 +122,11 @@ type endpoint struct {
 	// workerRunning specifies if a worker goroutine is running.
 	workerRunning bool
 
+	// workerCleanup specifies if the worker goroutine must perform cleanup
+	// before exitting. This can only be set to true when workerRunning is
+	// also true, and they're both protected by the mutex.
+	workerCleanup bool
+
 	// sendTSOk is used to indicate when the TS Option has been negotiated.
 	// When sendTSOk is true every non-RST segment should carry a TS as per
 	// RFC7323#section-1.1
@@ -277,6 +282,8 @@ func (e *endpoint) Close() {
 	// for reuse after Close() is called. If also registered, it means this
 	// is a listening socket, so we must unregister as well otherwise the
 	// next user would fail in Listen() when trying to register.
+	// 释放绑定端口 客户端释放随机绑定的port
+	// 注销协议栈中的端点
 	if e.isPortReserved {
 		e.stack.ReleasePort(e.effectiveNetProtos, ProtocolNumber, e.id.LocalAddress, e.id.LocalPort)
 		e.isPortReserved = false
@@ -287,10 +294,44 @@ func (e *endpoint) Close() {
 		}
 	}
 
-	logger.TODO("添加清理资源的逻辑")
+	tcpip.AddDanglingEndpoint(e)
+	if !e.workerRunning { // workerRunning 监听者 客户端 tcp连接 都会设置
+		e.cleanupLocked()
+	} else {
+		e.workerCleanup = true // 在端点调用了 Close 后将会走这个分支
+		e.notifyProtocolGoroutine(notifyClose)
+	}
 	e.mu.Unlock()
 }
 
+// cleanupLocked frees all resources associated with the endpoint. It is called
+// 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 { // 监听者
+		close(e.acceptedChan)
+		for n := range e.acceptedChan {
+			n.mu.Lock()
+			n.resetConnectionLocked(tcpip.ErrConnectionAborted)
+			n.mu.Unlock()
+			n.Close()
+		}
+		e.acceptedChan = nil
+	}
+	e.workerCleanup = false
+
+	// 注销掉这个端点
+	if e.isRegistered {
+		e.stack.UnregisterTransportEndpoint(e.boundNICID, e.effectiveNetProtos, ProtocolNumber, e.id)
+	}
+
+	// 释放掉这个路由
+	e.route.Release()
+	tcpip.DeleteDanglingEndpoint(e)
+}
+
 // Read 从tcp的接收队列中读取数据
 func (e *endpoint) Read(*tcpip.FullAddress) (buffer.View, tcpip.ControlMessages, *tcpip.Error) {
 	e.mu.RLock()
@@ -596,8 +637,9 @@ func (e *endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error {
 	defer e.mu.Unlock()
 	e.shutdownFlags |= flags
 
+
 	switch e.state {
-	case stateConnected: // 客户端关闭
+	case stateConnected: // tcp连接关闭
 		// 不能直接关闭读数据包，因为关闭连接的时候四次挥手还需要读取报文。
 		if (e.shutdownFlags & tcpip.ShutdownWrite) != 0 {
 			e.rcvListMu.Lock()
@@ -605,7 +647,7 @@ func (e *endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error {
 			e.rcvListMu.Unlock()
 			if rcvBufUsed > 0 {
 				// 如果接收队列中还有数据 通知对端RESET
-				logger.TODO("通知对端RESET")
+				e.notifyProtocolGoroutine(notifyReset)
 				return nil
 			}
 		}
@@ -617,6 +659,7 @@ func (e *endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error {
 			break
 		}
 
+		// 发送一个 FIN 报文 告知对面关闭上层用户程序
 		// Queue fin segment.
 		s := newSegmentFromView(&e.route, e.id, nil)
 		e.sndQueue.PushBack(s)
@@ -627,8 +670,8 @@ func (e *endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error {
 
 		// 触发调用 handleClose
 		e.sndCloseWaker.Assert()
-	case stateListen: // 服务端关闭
-		logger.FIXME("添加服务端关闭逻辑")
+	case stateListen: // 监听器关闭
+		logger.FIXME("添加监听器关闭逻辑")
 	default:
 		return tcpip.ErrNotConnected
 	}

tcpip/transport/tcp/rcv.go

@@ -181,8 +181,9 @@ func (r *receiver) handleRcvdSegment(s *segment) {
 
 	// tcp的可靠性：通过使用当前段，我们可能填补了序列号域中的间隙，该间隙允许现在使用待处理段。
 	// 所以试着去消费等待处理段。
+	// 当进行关闭操作的时候 只关写 不关读
 	for !r.closed && r.pendingRcvdSegments.Len() > 0 {
-		//log.Fatal("出现空隙端", r.pendingRcvdSegments.Len())
+		//log.Fatal("出现空隙段", r.pendingRcvdSegments.Len())
 		s := r.pendingRcvdSegments[0]
 		segLen := seqnum.Size(s.data.Size())
 		segSeq := s.sequenceNumber

tcpip/transport/tcp/snd.go

@@ -20,7 +20,7 @@ const (
 
 	// InitialCwnd is the initial congestion window.
 	// 初始拥塞窗口大小
-	InitialCwnd = 4
+	InitialCwnd = 10
 
 	// nDupAckThreshold is the number of duplicate ACK's required
 	// before fast-retransmit is entered.
@@ -593,14 +593,14 @@ func (s *sender) sendData() {
 
 		if !dataSent { // 没有成功发送任何数据
 			dataSent = true
-			// TODO
+			s.ep.disableKeepaliveTimer()
 		}
 
 		// 发送包 开始计算RTT
 		s.sendSegment(seg.data, seg.flags, seg.sequenceNumber)
 		// 发送一个数据段后，更新sndNxt
 		if s.sndNxt.LessThan(segEnd) {
-			log.Println("更新sndNxt", s.sndNxt, " 为 ", segEnd, "下一次发送的数据头为", segEnd)
+			log.Println(s.ep.id.LocalPort, " 更新sndNxt", s.sndNxt, " 为 ", segEnd, "下一次发送的数据头为", segEnd)
 			s.sndNxt = segEnd
 		}
 	}