mirror of
https://github.com/impact-eintr/netstack.git
synced 2025-10-07 05:40:52 +08:00
282 lines
7.9 KiB
Go
282 lines
7.9 KiB
Go
package udp
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import (
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"log"
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"netstack/tcpip"
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"netstack/tcpip/buffer"
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"netstack/tcpip/header"
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"netstack/tcpip/stack"
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"netstack/waiter"
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"sync"
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)
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// 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
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type udpPacket struct {
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udpPacketEntry // 链表实现
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// TODO 需要添加
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}
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type endpointState int
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// 表示UDP端的状态参数
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const (
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stateInitial endpointState = iota
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stateBound
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stateConnected
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stateClosed
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)
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type endpoint struct {
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stack *stack.Stack // udp所依赖的用户协议栈
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netProto tcpip.NetworkProtocolNumber // udp网络协议号 ipv4/ipv6
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waiterQueue *waiter.Queue // TODO 需要解析
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// TODO 需要解析
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// The following fields are used to manage the receive queue, and are
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// protected by rcvMu.
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rcvMu sync.Mutex
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rcvReady bool
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rcvList udpPacketList
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rcvBufSizeMax int
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rcvBufSize int
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rcvClosed bool
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rcvTimestamp bool
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// The following fields are protected by the mu mutex.
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mu sync.RWMutex
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sndBufSize int // 发送缓冲区大小
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id stack.TransportEndpointID
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state endpointState
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bindNICID tcpip.NICID // 绑定的网卡
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regNICID tcpip.NICID //
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route stack.Route // 路由? TODO
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dstPort uint16 // 目标端口
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v6only bool // 仅支持ipv6
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multicastTTL uint8 // 广播TTL
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// shutdownFlags represent the current shutdown state of the endpoint.
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shutdownFlags tcpip.ShutdownFlags
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// TODO
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// effectiveNetProtos contains the network protocols actually in use. In
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// most cases it will only contain "netProto", but in cases like IPv6
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// endpoints with v6only set to false, this could include multiple
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// protocols (e.g., IPv6 and IPv4) or a single different protocol (e.g.,
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// IPv4 when IPv6 endpoint is bound or connected to an IPv4 mapped
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// address). 当前生效的网络层协议
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effectiveNetProtos []tcpip.NetworkProtocolNumber
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}
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func newEndpoint(stack *stack.Stack, netProto tcpip.NetworkProtocolNumber,
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waiterQueue *waiter.Queue) *endpoint {
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log.Println("新建一个udp端")
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return &endpoint{
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stack: stack,
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netProto: netProto,
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waiterQueue: waiterQueue,
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multicastTTL: 1,
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rcvBufSizeMax: 32 * 1024,
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sndBufSize: 32 * 1024}
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}
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// Close UDP端的关闭，释放相应的资源
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func (e *endpoint) Close() {
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e.mu.Lock()
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e.shutdownFlags = tcpip.ShutdownRead | tcpip.ShutdownWrite
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switch e.state {
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case stateBound, stateConnected:
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// 释放在协议栈中注册的UDP端
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e.stack.UnregisterTransportEndpoint(e.regNICID, e.effectiveNetProtos, ProtocolNumber, e.id)
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// 释放端口占用
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e.stack.ReleasePort(e.effectiveNetProtos, ProtocolNumber, e.id.LocalAddress, e.id.LocalPort)
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}
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// TODO
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e.mu.Unlock()
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}
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func (e *endpoint) Read(*tcpip.FullAddress) (buffer.View, tcpip.ControlMessages, *tcpip.Error) {
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return nil, tcpip.ControlMessages{}, nil
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}
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func (e *endpoint) Write(tcpip.Payload, tcpip.WriteOptions) (uintptr, <-chan struct{}, *tcpip.Error) {
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return 0, nil, nil
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}
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func (e *endpoint) Peek([][]byte) (uintptr, tcpip.ControlMessages, *tcpip.Error) {
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return 0, tcpip.ControlMessages{}, nil
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}
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// IPV6于IPV4地址的映射
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func (e *endpoint) checkV4Mapped(addr *tcpip.FullAddress, allowMismatch bool) (tcpip.NetworkProtocolNumber, *tcpip.Error) {
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netProto := e.netProto
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if header.IsV4MappedAddress(addr.Addr) {
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// Fail if using a v4 mapped address on a v6only endpoint.
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if e.v6only {
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return 0, tcpip.ErrNoRoute
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}
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netProto = header.IPv4ProtocolNumber
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addr.Addr = addr.Addr[header.IPv6AddressSize-header.IPv4AddressSize:]
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if addr.Addr == "\x00\x00\x00\x00" {
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addr.Addr = ""
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}
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// Fail if we are bound to an IPv6 address.
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if !allowMismatch && len(e.id.LocalAddress) == 16 {
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return 0, tcpip.ErrNetworkUnreachable
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}
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}
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// Fail if we're bound to an address length different from the one we're
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// checking.
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// 源地址用与目标地址使用的ip协议不能不一致
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if l := len(e.id.LocalAddress); l != 0 && l != len(addr.Addr) {
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return 0, tcpip.ErrInvalidEndpointState
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}
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return netProto, nil
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}
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func (e *endpoint) Connect(address tcpip.FullAddress) *tcpip.Error {
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log.Println("连接")
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return nil
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}
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func (e *endpoint) Shutdown(flags tcpip.ShutdownFlags) *tcpip.Error {
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return nil
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}
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func (e *endpoint) Listen(backlog int) *tcpip.Error {
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return nil
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}
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func (e *endpoint) Accept() (tcpip.Endpoint, *waiter.Queue, *tcpip.Error) {
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return nil, nil, nil
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}
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func (e *endpoint) registerWithStack(nicid tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber,
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id stack.TransportEndpointID) (stack.TransportEndpointID, *tcpip.Error) {
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if e.id.LocalPort == 0 { // 一个没有绑定过端口的udp端
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port, err := e.stack.ReservePort(netProtos, ProtocolNumber, id.LocalAddress, id.LocalPort) // 为这个udp端绑定一个端口
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if err != nil {
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return id, err
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}
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id.LocalPort = port
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}
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err := e.stack.RegisterTransportEndpoint(nicid, netProtos, ProtocolNumber, id, e)
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if err != nil {
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// 释放端口
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e.stack.ReleasePort(netProtos, ProtocolNumber, id.LocalAddress, id.LocalPort)
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}
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return id, err
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}
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func (e *endpoint) bindLocked(addr tcpip.FullAddress, commit func() *tcpip.Error) *tcpip.Error {
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// 不是初始状态的UDP实现不允许绑定
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if e.state != stateInitial {
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return tcpip.ErrInvalidEndpointState
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}
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netProto, err := e.checkV4Mapped(&addr, true)
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if err != nil {
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return nil
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}
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netProtos := []tcpip.NetworkProtocolNumber{netProto}
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if netProto == header.IPv6ProtocolNumber && !e.v6only && addr.Addr == "" { // IPv6 && 支持ipv4 & 任意地址
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netProtos = []tcpip.NetworkProtocolNumber{
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header.IPv6ProtocolNumber,
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header.IPv4ProtocolNumber,
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}
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}
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// 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
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if len(addr.Addr) != 0 {
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if e.stack.CheckLocalAddress(addr.NIC, netProto, addr.Addr) == 0 {
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return tcpip.ErrBadLocalAddress
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}
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}
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// 开始绑定 绑定的时候 传输端ID : srcIP + srcPort
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id := stack.TransportEndpointID{
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LocalAddress: addr.Addr,
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LocalPort: addr.Port,
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}
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// 在协议栈中注册该UDP端
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id, err = e.registerWithStack(addr.NIC, netProtos, id)
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if err != nil {
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return err
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}
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// 如果指定了 commit 函数 执行并处理错误
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if commit != nil {
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if err := commit(); err != nil {
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// Unregister, the commit failed.
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e.stack.UnregisterTransportEndpoint(addr.NIC, netProtos, ProtocolNumber, id)
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e.stack.ReleasePort(netProtos, ProtocolNumber, id.LocalAddress, id.LocalPort)
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return err
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}
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}
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e.id = id
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e.regNICID = addr.NIC
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e.effectiveNetProtos = netProtos
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// Mark endpoint as bound.
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// 标记状态为已绑定
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e.state = stateBound
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return nil
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}
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// Bind binds the endpoint to a specific local address and port.
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// Specifying a NIC is optional.
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// Bind 将该UDP端绑定本地的一个IP+端口
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// 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
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func (e *endpoint) Bind(addr tcpip.FullAddress, commit func() *tcpip.Error) *tcpip.Error {
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e.mu.Lock()
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defer e.mu.Unlock()
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// 执行绑定IP+端口操作
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err := e.bindLocked(addr, commit)
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if err != nil {
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return err
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}
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// 绑定的网卡ID
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e.bindNICID = addr.NIC
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return nil
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}
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func (e *endpoint) GetLocalAddress() (tcpip.FullAddress, *tcpip.Error) {
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return tcpip.FullAddress{}, nil
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}
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func (e *endpoint) GetRemoteAddress() (tcpip.FullAddress, *tcpip.Error) {
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return tcpip.FullAddress{}, nil
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}
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func (e *endpoint) Readiness(mask waiter.EventMask) waiter.EventMask {
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return waiter.EventErr
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}
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func (e *endpoint) SetSockOpt(opt interface{}) *tcpip.Error {
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return nil
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}
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func (e *endpoint) GetSockOpt(opt interface{}) *tcpip.Error {
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return nil
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}
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// 从网络层接收到UDP数据报时的处理函数
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func (e *endpoint) HandlePacket(r *stack.Route, id stack.TransportEndpointID, vv buffer.VectorisedView) {
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}
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// HandleControlPacket implements stack.TransportEndpoint.HandleControlPacket.
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func (e *endpoint) HandleControlPacket(id stack.TransportEndpointID, typ stack.ControlType, extra uint32, vv buffer.VectorisedView) {
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}
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