tcp太痛苦了 功能好多流程还都杂糅在一起

cmd/tcpclient/main.go

@@ -4,28 +4,17 @@ import (
 	"fmt"
 	"log"
 	"net"
-	"time"
 )
 
 func main() {
-	go func() {
 	conn, err := net.Dial("tcp", "192.168.1.1:9999")
 	if err != nil {
 		fmt.Println("err : ", err)
 		return
 	}
-		log.Println("连接建立")
-		conn.Write([]byte("helloworld"))
-		log.Println("发送了数据")
 	//buf := make([]byte, 1024)
 	//conn.Read(buf)
-		conn.Close()
-	}()
-
-	t := time.NewTimer(1000 * time.Millisecond)
-	select {
-	case <-t.C:
-		return
+	if err = conn.Close(); err != nil {
+		log.Fatal(err)
 	}
-
 }

tcpip/transport/tcp/accept.go

@@ -222,7 +222,7 @@ func (l *listenContext) createEndpointAndPerformHandshake(s *segment, opts *head
 	irs := s.sequenceNumber
 	cookie := l.createCookie(s.id, irs, encodeMSS(opts.MSS))
 	logger.GetInstance().Info(logger.HANDSHAKE, func() {
-		log.Println("收到一个远端握手申请", irs, "客户端请携带 标记 iss", cookie)
+		log.Println("收到一个远端握手申请 SYN seq=", irs, "客户端请携带 标记 iss ", cookie, "+1")
 	})
 	ep, err := l.createConnectedEndpoint(s, cookie, irs, opts)
 	if err != nil {

tcpip/transport/tcp/connect.go

@@ -95,11 +95,11 @@ func (h *handshake) resetState() *tcpip.Error {
 	}
 	// 初始化状态为 SynSent
 	h.state = handshakeSynSent
-	log.Println("收到 syn 同步报文 设置tcp状态为 [sent]")
 	h.flags = flagSyn
 	h.ackNum = 0
 	h.mss = 0
 	h.iss = seqnum.Value(uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24)
+	log.Println("收到 syn 同步报文 设置tcp状态为 [sent]")
 
 	return nil
 }
@@ -109,7 +109,6 @@ func (h *handshake) resetState() *tcpip.Error {
 func (h *handshake) resetToSynRcvd(iss seqnum.Value, irs seqnum.Value, opts *header.TCPSynOptions) {
 	h.active = false
 	h.state = handshakeSynRcvd
-	log.Println("发送 syn|ack 确认报文 设置tcp状态为 [rcvd]")
 	h.flags = flagSyn | flagAck
 	h.iss = iss
 	h.ackNum = irs + 1 // NOTE ACK = synNum + 1
@@ -448,7 +447,7 @@ func sendTCP(r *stack.Route, id stack.TransportEndpointID, data buffer.Vectorise
 		r.Stats().TCP.ResetsSent.Increment()
 	}
 
-	log.Printf("send tcp %s segment to %s, seq: %d, ack: %d, rcvWnd: %d",
+	log.Printf("send tcp %s segment to %s, seq: |%d|, ack: %d, rcvWnd: %d",
 		flagString(flags), fmt.Sprintf("%s:%d", id.RemoteAddress, id.RemotePort),
 		seq, ack, rcvWnd)
 
@@ -538,7 +537,7 @@ func (e *endpoint) handleSegments() *tcpip.Error {
 			// 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.snd.handleRcvdSegment(s)
+			e.snd.handleRcvdSegment(s)
 		}
 		s.decRef() // 该segment处理完成
 	}

tcpip/transport/tcp/endpoint.go

@@ -599,7 +599,7 @@ func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, vv
 		if _, err := e.GetRemoteAddress(); err != nil {
 			prifix = "监听者"
 		}
-		log.Printf(prifix+"收到 tcp [%s] 报文片段 from %s, seq: %d, ack: %d",
+		log.Printf(prifix+"收到 tcp [%s] 报文片段 from %s, seq: %d, ack: |%d|",
 			flagString(s.flags), fmt.Sprintf("%s:%d", s.id.RemoteAddress, s.id.RemotePort),
 			s.sequenceNumber, s.ackNumber)
 

tcpip/transport/tcp/rcv.go

@@ -24,7 +24,7 @@ type receiver struct {
 func newReceiver(ep *endpoint, irs seqnum.Value, rcvWnd seqnum.Size, rcvWndScale uint8) *receiver {
 	r := &receiver{
 		ep:          ep,
-		rcvNxt:      irs + 1,
+		rcvNxt:      irs + 1, // 成功建立连接后期望读取的第一个字节序号
 		rcvAcc:      irs.Add(rcvWnd + 1),
 		rcvWndScale: rcvWndScale,
 	}
@@ -78,7 +78,6 @@ func (r *receiver) consumeSegment(s *segment, segSeq seqnum.Value, segLen seqnum
 	r.rcvNxt = segSeq.Add(segLen)
 	logger.GetInstance().Info(logger.TCP, func() {
 	})
-	log.Println("下一个期望接收的字节序列号", r.rcvNxt)
 
 	// 如果收到 fin 报文
 	if s.flagIsSet(flagFin) {
@@ -86,7 +85,7 @@ func (r *receiver) consumeSegment(s *segment, segSeq seqnum.Value, segLen seqnum
 		r.rcvNxt++
 
 		// 收到 fin，立即回复 ack
-		r.ep.snd.sendAck()
+		r.ep.snd.sendAck() // FIXME 不应该是 seq+2 捏
 	}
 
 	return true

tcpip/transport/tcp/snd.go

@@ -1,6 +1,7 @@
 package tcp
 
 import (
+	"log"
 	"netstack/tcpip"
 	"netstack/tcpip/buffer"
 	"netstack/tcpip/seqnum"
@@ -66,7 +67,9 @@ func newSender(ep *endpoint, iss, irs seqnum.Value, sndWnd seqnum.Size, mss uint
 }
 
 func (s *sender) sendAck() {
-	s.sendSegment(buffer.VectorisedView{}, flagAck, s.sndNxt)
+	log.Println("发送字节序", s.sndNxt)
+	s.sendSegment(buffer.VectorisedView{}, flagAck, s.sndNxt) // seq = cookies+1 ack ack|fin.seq+1
+	s.sendSegment(buffer.VectorisedView{}, flagFin, 0)
 }
 
 // sendSegment sends a new segment containing the given payload, flags and
@@ -85,3 +88,15 @@ func (s *sender) sendSegment(data buffer.VectorisedView, flags byte, seq seqnum.
 
 	return s.ep.sendRaw(data, flags, seq, rcvNxt, rcvWnd)
 }
+
+// 收到段时调用 handleRcvdSegment 它负责更新与发送相关的状态
+func (s *sender) handleRcvdSegment(seg *segment) {
+	// 现在某些待处理数据已被确认，或者窗口打开，或者由于快速恢复期间出现重复的ack而导致拥塞窗口膨胀，
+	// 因此发送更多数据。如果需要，这也将重新启用重传计时器。
+	s.sendData()
+}
+
+// 发送数据段，最终调用 sendSegment 来发送
+func (s *sender) sendData() {
+
+}