端口编码、测试结束

网络协议号:传输层协议号:端口 这就是一个端口 一个端口可以绑定多个网络层地址 ipv4-tcp-9999:{192.168.1.1, 172.176.10.1}
也可以绑定空值 表示 0.0.0.0:9999 本机的所有网卡的所有ip的9999端口都为 tcp/udp 所占用
所有目标端口是9999的数据都会流向这个绑定了9999端口的传输层实现

cmd/port/main.go

@@ -152,8 +152,9 @@ func udpListen(s *stack.Stack, proto tcpip.NetworkProtocolNumber, localPort int)
 	}
 
 	// 绑定IP和端口，这里的IP地址为空，表示绑定任何IP
+	// 0.0.0.0:9999 这台机器上的所有ip的9999段端口数据都会使用该传输层实现
 	// 此时就会调用端口管理器
-	if err := ep.Bind(tcpip.FullAddress{0, "", uint16(localPort)}, nil); err != nil {
+	if err := ep.Bind(tcpip.FullAddress{NIC: 0, Addr: "", Port: uint16(localPort)}, nil); err != nil {
 		log.Fatal("Bind failed: ", err)
 	}
 

tcpip/ports/ports.go

@@ -1,6 +1,7 @@
 package ports
 
 import (
+	"log"
 	"math"
 	"math/rand"
 	"netstack/tcpip"
@@ -87,7 +88,7 @@ func (s *PortManager) isPortAvailableLocked(networks []tcpip.NetworkProtocolNumb
 	for _, network := range networks { // 遍历网络协议
 		desc := portDescriptor{network: network, transport: transport, port: port} // 构造端口描述符
 		if addrs, ok := s.allocatedPorts[desc]; ok {                               // 检查端口描述符绑定的ip集合
-			if !addrs.isAvailable(addr) { // 该集合中已经有这个ip
+			if !addrs.isAvailable(addr) { // 该集合中已经有这个ip 或者是"" 也就是 0.0.0.0
 				return false
 			}
 		}
@@ -101,5 +102,64 @@ func (s *PortManager) isPortAvailableLocked(networks []tcpip.NetworkProtocolNumb
 func (s *PortManager) ReservePort(networks []tcpip.NetworkProtocolNumber,
 	transport tcpip.TransportProtocolNumber,
 	addr tcpip.Address, port uint16) (reservedPort uint16, err *tcpip.Error) {
-	return 0, nil
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	// defer log.Println(transport, "成功分配端口", *(&reservedPort)) TODO 这样写就有问题 defer给直接取值了?
+	defer func() {
+		log.Println(transport, "成功分配端口", *(&reservedPort))
+	}()
+
+	// 指定端口进行绑定
+	if port != 0 {
+		if !s.reserveSpecificPort(networks, transport, addr, port) {
+			return 0, tcpip.ErrPortInUse // 已经被占用
+		}
+		reservedPort = port
+		return
+	}
+	// 随机分配
+	reservedPort, err = s.PickEphemeralPort(func(p uint16) (bool, *tcpip.Error) {
+		return s.reserveSpecificPort(networks, transport, addr, p), nil
+	})
+	return reservedPort, nil
+}
+
+// reserveSpecificPort 尝试根据协议号和IP地址绑定一个端口
+func (s *PortManager) reserveSpecificPort(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber,
+	addr tcpip.Address, port uint16) bool {
+	if !s.isPortAvailableLocked(networks, transport, addr, port) {
+		return false
+	}
+
+	// 根据给定的网络层协议号绑定端口
+	for _, network := range networks {
+		desc := portDescriptor{network: network, transport: transport, port: port} // ipv4-udp-9999
+		m, ok := s.allocatedPorts[desc]
+		if !ok {
+			m = make(bindAddresses) // Set of IP
+			s.allocatedPorts[desc] = m
+		}
+		// 注册该地址被绑定了
+		m[addr] = struct{}{}
+	}
+	return true
+}
+
+// ReleasePort 释放绑定的端口，以便别的程序复用。
+func (s *PortManager) ReleasePort(networks []tcpip.NetworkProtocolNumber, transport tcpip.TransportProtocolNumber,
+	addr tcpip.Address, port uint16) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	// 删除绑定关系
+	for _, network := range networks {
+		desc := portDescriptor{network, transport, port}
+		if m, ok := s.allocatedPorts[desc]; ok {
+			log.Println(transport, "释放", port)
+			delete(m, addr)
+			if len(m) == 0 {
+				delete(s.allocatedPorts, desc)
+			}
+		}
+	}
 }

tcpip/stack/registration.go

@@ -181,8 +181,12 @@ type NetworkEndpointID struct {
 
 // ==============================传输层相关==============================
 
+// TransportEndpointID 是某个传输层实现的标识
 type TransportEndpointID struct {
-	// TODO
+	LocalPort     uint16
+	LocalAddress  tcpip.Address
+	remotePort    uint16
+	RemoteAddress tcpip.Address
 }
 
 // ControlType 是网络层控制消息的类型
@@ -197,7 +201,7 @@ const (
 // TransportEndpoint 传输层实现接口
 type TransportEndpoint interface {
 	HandlePacket(r *Route, id TransportEndpointID, vv buffer.VectorisedView)
-	HandleControlPacker(id TransportEndpointID, typ ControlType, extra uint32, vv buffer.VectorisedView)
+	HandleControlPacket(id TransportEndpointID, typ ControlType, extra uint32, vv buffer.VectorisedView)
 }
 
 // TransportProtocol 传输层协议 TCP OR UDP

tcpip/stack/stack.go

@@ -162,7 +162,7 @@ func (s *Stack) NewEndpoint(transport tcpip.TransportProtocolNumber,
 	if !ok {
 		return nil, tcpip.ErrUnknownProtocol
 	}
-	return t.proto.NewEndpoint(s, network, waiterQueue)
+	return t.proto.NewEndpoint(s, network, waiterQueue) // 新建一个传输层实现
 }
 
 // CreateNIC 根据给定的网卡号 和 链路层设备号 创建一个网卡对象
@@ -300,7 +300,8 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address,
 }
 
 // ===============本机链路层缓存实现==================
-// 检查本地是否绑定过该网络层地址
+
+// CheckLocalAddress 检查本地是否绑定过该网络层地址 注意 NICID 为0表示寻找本机所有网卡
 func (s *Stack) CheckLocalAddress(nicid tcpip.NICID, protocol tcpip.NetworkProtocolNumber, addr tcpip.Address) tcpip.NICID {
 	s.mu.RLock()
 	defer s.mu.RUnlock()
@@ -362,3 +363,39 @@ func (s *Stack) RemoveWaker(nicid tcpip.NICID, addr tcpip.Address, waker *sleep.
 		s.linkAddrCache.removeWaker(fullAddr, waker)
 	}
 }
+
+// RegisterTransportEndpoint 协议栈或者NIC的分流器注册给定传输层端点。
+// 收到的与提供的id匹配的数据包将被传送到给定的端点;指定nic是可选的，但特定于nic的ID优先于全局ID。
+// 最终调用 demuxer.registerEndpoint 函数来实现注册。
+func (s *Stack) RegisterTransportEndpoint(nicID tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber,
+	protocol tcpip.TransportProtocolNumber, id TransportEndpointID, ep TransportEndpoint) *tcpip.Error {
+	// TODO 需要实现
+	return nil
+}
+
+// UnregisterTransportEndpoint removes the endpoint with the given id from the
+// stack transport dispatcher.
+func (s *Stack) UnregisterTransportEndpoint(nicID tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber,
+	protocol tcpip.TransportProtocolNumber, id TransportEndpointID) {
+
+}
+
+// NetworkProtocolInstance returns the protocol instance in the stack for the
+// specified network protocol. This method is public for protocol implementers
+// and tests to use.
+func (s *Stack) NetworkProtocolInstance(num tcpip.NetworkProtocolNumber) NetworkProtocol {
+	if p, ok := s.networkProtocols[num]; ok {
+		return p
+	}
+	return nil
+}
+
+// TransportProtocolInstance returns the protocol instance in the stack for the
+// specified transport protocol. This method is public for protocol implementers
+// and tests to use.
+func (s *Stack) TransportProtocolInstance(num tcpip.TransportProtocolNumber) TransportProtocol {
+	if pState, ok := s.transportProtocols[num]; ok {
+		return pState.proto
+	}
+	return nil
+}

tcpip/tcpip.go

@@ -165,8 +165,20 @@ func (l LinkAddress) String() string {
 
 type LinkEndpointID uint64
 
+// TransportProtocolNumber 传输层协议号
 type TransportProtocolNumber uint32
 
+const (
+	UDPProtocolNumber = 17
+)
+
+func (t TransportProtocolNumber) String() string {
+	if t == UDPProtocolNumber {
+		return "UDP"
+	}
+	return "TCP"
+}
+
 type NetworkProtocolNumber uint32
 
 type NICID int32

tcpip/transport/udp/endpoint.go

@@ -4,16 +4,28 @@ import (
 	"log"
 	"netstack/tcpip"
 	"netstack/tcpip/buffer"
+	"netstack/tcpip/header"
 	"netstack/tcpip/stack"
 	"netstack/waiter"
 	"sync"
 )
 
 // udp报文结构 当收到udp报文时 会用这个结构来保存udp报文数据
-type udpPacker struct {
+type udpPacket struct {
+	udpPacketEntry // 链表实现
 	// TODO 需要添加
 }
 
+type endpointState int
+
+// 表示UDP端的状态参数
+const (
+	stateInitial endpointState = iota
+	stateBound
+	stateConnected
+	stateClosed
+)
+
 type endpoint struct {
 	stack       *stack.Stack                // udp所依赖的用户协议栈
 	netProto    tcpip.NetworkProtocolNumber // udp网络协议号 ipv4/ipv6
@@ -31,18 +43,59 @@ type endpoint struct {
 	rcvTimestamp  bool
 
 	// The following fields are protected by the mu mutex.
-	mu sync.RWMutex
+	mu           sync.RWMutex
-	// TODO 需要添加
+	sndBufSize   int // 发送缓冲区大小
+	id           stack.TransportEndpointID
+	state        endpointState
+	bindNICID    tcpip.NICID // 绑定的网卡
+	regNICID     tcpip.NICID //
+	route        stack.Route // 路由? TODO
+	dstPort      uint16      // 目标端口
+	v6only       bool        // 仅支持ipv6
+	multicastTTL uint8       // 广播TTL
+
+	// shutdownFlags represent the current shutdown state of the endpoint.
+	shutdownFlags tcpip.ShutdownFlags
+
+	// TODO
+
+	// effectiveNetProtos contains the network protocols actually in use. In
+	// most cases it will only contain "netProto", but in cases like IPv6
+	// endpoints with v6only set to false, this could include multiple
+	// protocols (e.g., IPv6 and IPv4) or a single different protocol (e.g.,
+	// IPv4 when IPv6 endpoint is bound or connected to an IPv4 mapped
+	// address). 当前生效的网络层协议
+	effectiveNetProtos []tcpip.NetworkProtocolNumber
 }
 
 func newEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber,
 	waiterQueue *waiter.Queue) *endpoint {
-	log.Println("新建传输层实现")
+	log.Println("新建一个udp端")
-	return &endpoint{}
+	return &endpoint{
+		stack:         stack,
+		netProto:      netProto,
+		waiterQueue:   waiterQueue,
+		multicastTTL:  1,
+		rcvBufSizeMax: 32 * 1024,
+		sndBufSize:    32 * 1024}
 }
 
+// Close UDP端的关闭，释放相应的资源
 func (e *endpoint) Close() {
+	e.mu.Lock()
 
+	e.shutdownFlags = tcpip.ShutdownRead | tcpip.ShutdownWrite
+
+	switch e.state {
+	case stateBound, stateConnected:
+		// 释放在协议栈中注册的UDP端
+		e.stack.UnregisterTransportEndpoint(e.regNICID, e.effectiveNetProtos, ProtocolNumber, e.id)
+		// 释放端口占用
+		e.stack.ReleasePort(e.effectiveNetProtos, ProtocolNumber, e.id.LocalAddress, e.id.LocalPort)
+	}
+
+	// TODO
+	e.mu.Unlock()
 }
 
 func (e *endpoint) Read(*tcpip.FullAddress) (buffer.View, tcpip.ControlMessages, *tcpip.Error) {
@@ -57,6 +110,37 @@ func (e *endpoint) Peek([][]byte) (uintptr, tcpip.ControlMessages, *tcpip.Error)
 	return 0, tcpip.ControlMessages{}, nil
 }
 
+// IPV6于IPV4地址的映射
+func (e *endpoint) checkV4Mapped(addr *tcpip.FullAddress, allowMismatch bool) (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 == "\x00\x00\x00\x00" {
+			addr.Addr = ""
+		}
+
+		// Fail if we are bound to an IPv6 address.
+		if !allowMismatch && len(e.id.LocalAddress) == 16 {
+			return 0, tcpip.ErrNetworkUnreachable
+		}
+	}
+
+	// Fail if we're bound to an address length different from the one we're
+	// checking.
+	// 源地址用与目标地址使用的ip协议不能不一致
+	if l := len(e.id.LocalAddress); l != 0 && l != len(addr.Addr) {
+		return 0, tcpip.ErrInvalidEndpointState
+	}
+
+	return netProto, nil
+}
+
 func (e *endpoint) Connect(address tcpip.FullAddress) *tcpip.Error {
 	return nil
 }
@@ -73,12 +157,96 @@ func (e *endpoint) Accept() (tcpip.Endpoint, *waiter.Queue, *tcpip.Error) {
 	return nil, nil, nil
 }
 
+func (e *endpoint) registerWithStack(nicid tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber,
+	id stack.TransportEndpointID) (stack.TransportEndpointID, *tcpip.Error) {
+	if e.id.LocalPort == 0 { // 一个没有绑定过端口的udp端
+		port, err := e.stack.ReservePort(netProtos, ProtocolNumber, id.LocalAddress, id.LocalPort) // 为这个udp端绑定一个端口
+		if err != nil {
+			return id, err
+		}
+		id.LocalPort = port
+	}
+	err := e.stack.RegisterTransportEndpoint(nicid, netProtos, ProtocolNumber, id, e)
+	if err != nil {
+		// 释放端口
+		e.stack.ReleasePort(netProtos, ProtocolNumber, id.LocalAddress, id.LocalPort)
+	}
+	return id, err
+}
+
+func (e *endpoint) bindLocked(addr tcpip.FullAddress, commit func() *tcpip.Error) *tcpip.Error {
+	// 不是初始状态的UDP实现不允许绑定
+	if e.state != stateInitial {
+		return tcpip.ErrInvalidEndpointState
+	}
+
+	netProto, err := e.checkV4Mapped(&addr, true)
+	if err != nil {
+		return nil
+	}
+
+	netProtos := []tcpip.NetworkProtocolNumber{netProto}
+	if netProto == header.IPv6ProtocolNumber && !e.v6only && addr.Addr == "" { // IPv6 && 支持ipv4 & 任意地址
+		netProtos = []tcpip.NetworkProtocolNumber{
+			header.IPv6ProtocolNumber,
+			header.IPv4ProtocolNumber,
+		}
+	}
+
+	// 不是任意地址的话 需要检验本地网卡是否绑定个这个ip地址
+	if len(addr.Addr) != 0 {
+		if e.stack.CheckLocalAddress(addr.NIC, netProto, addr.Addr) == 0 {
+			return tcpip.ErrBadLocalAddress
+		}
+	}
+
+	// 开始绑定 绑定的时候 传输端ID : srcIP + srcPort
+	id := stack.TransportEndpointID{
+		LocalAddress: addr.Addr,
+		LocalPort:    addr.Port,
+	}
+	// 在协议栈中注册该UDP端
+	id, err = e.registerWithStack(addr.NIC, netProtos, id)
+	if err != nil {
+		return err
+	}
+	// 如果指定了 commit 函数 执行并处理错误
+	if commit != nil {
+		if err := commit(); err != nil {
+			// Unregister, the commit failed.
+			e.stack.UnregisterTransportEndpoint(addr.NIC, netProtos, ProtocolNumber, id)
+			e.stack.ReleasePort(netProtos, ProtocolNumber, id.LocalAddress, id.LocalPort)
+			return err
+		}
+	}
+
+	e.id = id
+	e.regNICID = addr.NIC
+	e.effectiveNetProtos = netProtos
+
+	// Mark endpoint as bound.
+	// 标记状态为已绑定
+	e.state = stateBound
+
+	return nil
+}
+
 // Bind binds the endpoint to a specific local address and port.
 // Specifying a NIC is optional.
 // Bind 将该UDP端绑定本地的一个IP+端口
 // 例如：绑定本地0.0.0.0的9000端口，那么其他机器给这台机器9000端口发消息，该UDP端就能收到消息了
-func (e *endpoint) Bind(address tcpip.FullAddress, commit func() *tcpip.Error) *tcpip.Error {
+func (e *endpoint) Bind(addr tcpip.FullAddress, commit func() *tcpip.Error) *tcpip.Error {
-	log.Println("绑定端口", address)
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	// 执行绑定IP+端口操作
+	err := e.bindLocked(addr, commit)
+	if err != nil {
+		return err
+	}
+
+	// 绑定的网卡ID
+	e.bindNICID = addr.NIC
 	return nil
 }
 
@@ -101,3 +269,12 @@ func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
 func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
 	return nil
 }
+
+// 从网络层接收到UDP数据报时的处理函数
+func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, vv buffer.VectorisedView) {
+
+}
+
+// HandleControlPacket implements stack.TransportEndpoint.HandleControlPacket.
+func (e *endpoint) HandleControlPacket(id stack.TransportEndpointID, typ stack.ControlType, extra uint32, vv buffer.VectorisedView) {
+}

tcpip/transport/udp/protocol.go

@@ -1,7 +1,6 @@
 package udp
 
 import (
-	"log"
 	"netstack/tcpip"
 	"netstack/tcpip/buffer"
 	"netstack/tcpip/header"
@@ -28,7 +27,6 @@ func (*protocol) Number() tcpip.TransportProtocolNumber {
 // NewEndpoint creates a new udp endpoint.
 func (*protocol) NewEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber,
 	waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error) {
-	log.Println("新建udp传输层协议")
 	return newEndpoint(stack, netProto, waiterQueue), nil
 }