mirror of
https://github.com/impact-eintr/netstack.git
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365aebc353
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
402 lines
12 KiB
Go
402 lines
12 KiB
Go
package stack
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import (
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"log"
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"netstack/sleep"
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"netstack/tcpip"
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"netstack/tcpip/buffer"
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"netstack/tcpip/ports"
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"netstack/waiter"
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"sync"
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"time"
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)
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const (
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// ageLimit is set to the same cache stale time used in Linux.
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ageLimit = 1 * time.Minute
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// resolutionTimeout is set to the same ARP timeout used in Linux.
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resolutionTimeout = 1 * time.Second
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// resolutionAttempts is set to the same ARP retries used in Linux.
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resolutionAttempts = 3
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)
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// TODO 需要解读
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type TCPProbeFunc func(s TcpEndpointState)
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// TODO 需要解读
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type TcpEndpointState struct {
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// TODO 需要添加
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}
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// 传输层协议状态机 包含传输层协议以及默认处理方法
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type transportProtocolState struct {
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proto TransportProtocol
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defaultHandler func(*Route, TransportEndpointID, buffer.VectorisedView) bool
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}
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// Stack 是一个网络堆栈，具有所有支持的协议、NIC 和路由表。
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type Stack struct {
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transportProtocols map[tcpip.TransportProtocolNumber]*transportProtocolState // 各种传输层协议
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networkProtocols map[tcpip.NetworkProtocolNumber]NetworkProtocol // 各种网络层协议
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linkAddrResolvers map[tcpip.NetworkProtocolNumber]LinkAddressResolver // 各种链接解析器
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demux *transportDemuxer // 传输层的复用器
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stats tcpip.Stats // 网络栈的状态监测器
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linkAddrCache *linkAddrCache // 链路层地址的缓存
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mu sync.RWMutex
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nics map[tcpip.NICID]*NIC // 所有的网卡设备
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forwarding bool // 是否正在转发
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// route is the route table passed in by the user via SetRouteTable(),
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// it is used by FindRoute() to build a route for a specific
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// destination.
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routeTable []tcpip.Route // 路由表
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*ports.PortManager // 端口管理器
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// If not nil, then any new endpoints will have this probe function
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// invoked everytime they receive a TCP segment.
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tcpProbeFunc TCPProbeFunc
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// clock is used to generate user-visible times.
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clock tcpip.Clock
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}
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// Options contains optional Stack configuration.
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type Options struct {
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// Clock is an optional clock source used for timestampping packets.
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//
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// If no Clock is specified, the clock source will be time.Now.
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Clock tcpip.Clock
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// Stats are optional statistic counters.
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Stats tcpip.Stats
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}
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func New(network []string, transport []string, opts Options) *Stack {
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clock := opts.Clock
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if clock == nil {
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clock = &tcpip.StdClock{}
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}
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s := &Stack{
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transportProtocols: make(map[tcpip.TransportProtocolNumber]*transportProtocolState),
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networkProtocols: make(map[tcpip.NetworkProtocolNumber]NetworkProtocol),
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linkAddrResolvers: make(map[tcpip.NetworkProtocolNumber]LinkAddressResolver),
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nics: make(map[tcpip.NICID]*NIC),
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linkAddrCache: newLinkAddrCache(ageLimit, resolutionTimeout, resolutionAttempts),
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PortManager: ports.NewPortManager(),
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clock: clock,
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stats: opts.Stats.FillIn(),
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}
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// 添加指定的网络端协议 必须已经在init中注册过
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for _, name := range network {
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// 先检查这个网络协议是否注册过工厂方法
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netProtoFactory, ok := networkProtocols[name]
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if !ok {
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continue // 没有就略过
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}
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netProto := netProtoFactory() // 制造一个该型号协议的示实例
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s.networkProtocols[netProto.Number()] = netProto // 注册该型号的网络协议
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}
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// 添加指定的传输层协议 必已经在init中注册过
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for _, name := range transport {
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transProtoFactory, ok := transportProtocols[name]
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if !ok {
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continue
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}
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transProto := transProtoFactory() // 新建一个传输层协议
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s.transportProtocols[transProto.Number()] = &transportProtocolState{
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proto: transProto,
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}
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}
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// TODO 添加传输层分流器
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return s
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}
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func (s *Stack) Stats() tcpip.Stats {
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return s.stats
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}
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// SetForwarding enables or disables the packet forwarding between NICs.
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func (s *Stack) SetForwarding(enable bool) {
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// TODO: Expose via /proc/sys/net/ipv4/ip_forward.
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s.mu.Lock()
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s.forwarding = enable
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s.mu.Unlock()
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}
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// Forwarding returns if the packet forwarding between NICs is enabled.
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func (s *Stack) Forwarding() bool {
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// TODO: Expose via /proc/sys/net/ipv4/ip_forward.
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s.mu.RLock()
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defer s.mu.RUnlock()
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return s.forwarding
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}
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// SetRouteTable assigns the route table to be used by this stack. It
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// specifies which NIC to use for given destination address ranges.
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func (s *Stack) SetRouteTable(table []tcpip.Route) {
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s.mu.Lock()
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defer s.mu.Unlock()
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s.routeTable = table
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}
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// GetRouteTable returns the route table which is currently in use.
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func (s *Stack) GetRouteTable() []tcpip.Route {
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s.mu.Lock()
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defer s.mu.Unlock()
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return append([]tcpip.Route(nil), s.routeTable...)
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}
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// NewEndpoint 根据给定的网络层协议号和传输层协议号新建一个传输层实现
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func (s *Stack) NewEndpoint(transport tcpip.TransportProtocolNumber,
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network tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error) {
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t, ok := s.transportProtocols[transport]
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if !ok {
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return nil, tcpip.ErrUnknownProtocol
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}
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return t.proto.NewEndpoint(s, network, waiterQueue) // 新建一个传输层实现
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}
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// CreateNIC 根据给定的网卡号 和 链路层设备号 创建一个网卡对象
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func (s *Stack) CreateNIC(id tcpip.NICID, linkEP tcpip.LinkEndpointID) *tcpip.Error {
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return s.createNIC(id, "", linkEP, true)
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}
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// CreateNamedNIC creates a NIC with the provided id and link-layer endpoint,
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// and a human-readable name.
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func (s *Stack) CreateNamedNIC(id tcpip.NICID, name string, linkEP tcpip.LinkEndpointID) *tcpip.Error {
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return s.createNIC(id, name, linkEP, true)
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}
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// 新建一个网卡对象，并且激活它 激活就是准备好熊网卡中读取和写入数据
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func (s *Stack) createNIC(id tcpip.NICID, name string, linkEP tcpip.LinkEndpointID, enable bool) *tcpip.Error {
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ep := FindLinkEndpoint(linkEP)
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if ep == nil {
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return tcpip.ErrBadLinkEndpoint
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}
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s.mu.Lock()
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defer s.mu.Unlock()
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// Make sure id is unique
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if _, ok := s.nics[id]; ok {
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return tcpip.ErrDuplicateNICID
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}
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n := newNIC(s, id, name, ep)
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s.nics[id] = n
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if enable {
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n.attachLinkEndpoint()
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}
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return nil
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}
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// 给网卡添加ip地址
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func (s *Stack) AddAddress(id tcpip.NICID, protocol tcpip.NetworkProtocolNumber, addr tcpip.Address) *tcpip.Error {
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return s.AddAddressWithOptions(id, protocol, addr, CanBePrimaryEndpoint)
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}
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func (s *Stack) AddAddressWithOptions(id tcpip.NICID, protocol tcpip.NetworkProtocolNumber,
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addr tcpip.Address, peb PrimaryEndpointBehavior) *tcpip.Error {
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s.mu.RLock()
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defer s.mu.RUnlock()
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nic := s.nics[id]
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if nic == nil {
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return tcpip.ErrUnknownNICID
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}
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return nic.AddAddressWithOptions(protocol, addr, peb)
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}
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// AddSubnet adds a subnet range to the specified NIC.
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func (s *Stack) AddSubnet(id tcpip.NICID, protocol tcpip.NetworkProtocolNumber, subnet tcpip.Subnet) *tcpip.Error {
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s.mu.RLock()
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defer s.mu.RUnlock()
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if nic, ok := s.nics[id]; ok {
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nic.AddSubnet(protocol, subnet)
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return nil
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}
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return tcpip.ErrUnknownNICID
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}
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// RemoveSubnet removes the subnet range from the specified NIC.
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func (s *Stack) RemoveSubnet(id tcpip.NICID, subnet tcpip.Subnet) *tcpip.Error {
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s.mu.RLock()
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defer s.mu.RUnlock()
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if nic, ok := s.nics[id]; ok {
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nic.RemoveSubnet(subnet)
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return nil
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}
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return tcpip.ErrUnknownNICID
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}
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// ContainsSubnet reports whether the specified NIC contains the specified
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// subnet.
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func (s *Stack) ContainsSubnet(id tcpip.NICID, subnet tcpip.Subnet) (bool, *tcpip.Error) {
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s.mu.RLock()
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defer s.mu.RUnlock()
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if nic, ok := s.nics[id]; ok {
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return nic.ContainsSubnet(subnet), nil
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}
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return false, tcpip.ErrUnknownNICID
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}
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// 路由查找实现，比如当tcp建立连接时，会用该函数得到路由信息
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func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address,
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netProto tcpip.NetworkProtocolNumber) (Route, *tcpip.Error) {
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s.mu.RLock()
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defer s.mu.RUnlock()
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for i := range s.routeTable {
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if (id != 0 && id != s.routeTable[i].NIC) ||
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(len(remoteAddr) != 0 && !s.routeTable[i].Match(remoteAddr)) {
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continue
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}
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nic := s.nics[s.routeTable[i].NIC]
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if nic == nil {
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continue
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}
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var ref *referencedNetworkEndpoint
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if len(localAddr) != 0 {
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ref = nic.findEndpoint(netProto, localAddr, CanBePrimaryEndpoint)
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} else {
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ref = nic.primaryEndpoint(netProto)
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}
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if ref == nil {
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continue
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}
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if len(remoteAddr) == 0 {
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// If no remote address was provided, then the route
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// provided will refer to the link local address.
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remoteAddr = ref.ep.ID().LocalAddress // 发回自己? TODO
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}
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r := makeRoute(netProto, ref.ep.ID().LocalAddress, remoteAddr, nic.linkEP.LinkAddress(), ref)
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r.NextHop = s.routeTable[i].Gateway
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log.Println(r.LocalLinkAddress, r.LocalAddress, r.RemoteLinkAddress, r.RemoteAddress, r.NextHop)
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return r, nil
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}
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return Route{}, tcpip.ErrNoRoute
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}
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// ===============本机链路层缓存实现==================
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// 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
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func (s *Stack) CheckLocalAddress(nicid tcpip.NICID, protocol tcpip.NetworkProtocolNumber, addr tcpip.Address) tcpip.NICID {
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s.mu.RLock()
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defer s.mu.RUnlock()
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if nicid != 0 {
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nic := s.nics[nicid] // 先拿到网卡
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if nic == nil {
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return 0
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}
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ref := nic.findEndpoint(protocol, addr, CanBePrimaryEndpoint) // 看看这张网卡是否绑定过这个地址
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if ref == nil {
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return 0
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}
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ref.decRef() // 这个网络端实现使用结束 释放对它的占用
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return nic.id
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}
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// Go through all the NICs.
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for _, nic := range s.nics {
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ref := nic.findEndpoint(protocol, addr, CanBePrimaryEndpoint)
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if ref != nil {
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ref.decRef()
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return nic.id
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}
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}
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return 0
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}
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func (s *Stack) AddLinkAddress(nicid tcpip.NICID, addr tcpip.Address, linkAddr tcpip.LinkAddress) {
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fullAddr := tcpip.FullAddress{NIC: nicid, Addr: addr}
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s.linkAddrCache.add(fullAddr, linkAddr)
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}
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func (s *Stack) GetLinkAddress(nicid tcpip.NICID, addr, localAddr tcpip.Address,
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protocol tcpip.NetworkProtocolNumber, w *sleep.Waker) (tcpip.LinkAddress, <-chan struct{}, *tcpip.Error) {
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s.mu.RLock()
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// 获取网卡对象
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nic := s.nics[nicid]
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if nic == nil {
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s.mu.RUnlock()
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return "", nil, tcpip.ErrUnknownNICID
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}
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s.mu.RUnlock()
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fullAddr := tcpip.FullAddress{NIC: nicid, Addr: addr}
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// 根据网络层协议号找到对应的地址解析协议
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linkRes := s.linkAddrResolvers[protocol]
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return s.linkAddrCache.get(fullAddr, linkRes, localAddr, nic.linkEP, w)
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}
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func (s *Stack) RemoveWaker(nicid tcpip.NICID, addr tcpip.Address, waker *sleep.Waker) {
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s.mu.RLock()
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defer s.mu.RUnlock()
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if nic := s.nics[nicid]; nic == nil {
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fullAddr := tcpip.FullAddress{NIC: nicid, Addr: addr}
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s.linkAddrCache.removeWaker(fullAddr, waker)
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}
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}
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// RegisterTransportEndpoint 协议栈或者NIC的分流器注册给定传输层端点。
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// 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。
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// 最终调用 demuxer.registerEndpoint 函数来实现注册。
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func (s *Stack) RegisterTransportEndpoint(nicID tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber,
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protocol tcpip.TransportProtocolNumber, id TransportEndpointID, ep TransportEndpoint) *tcpip.Error {
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// TODO 需要实现
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return nil
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}
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// UnregisterTransportEndpoint removes the endpoint with the given id from the
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// stack transport dispatcher.
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func (s *Stack) UnregisterTransportEndpoint(nicID tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber,
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protocol tcpip.TransportProtocolNumber, id TransportEndpointID) {
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}
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// NetworkProtocolInstance returns the protocol instance in the stack for the
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// specified network protocol. This method is public for protocol implementers
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// and tests to use.
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func (s *Stack) NetworkProtocolInstance(num tcpip.NetworkProtocolNumber) NetworkProtocol {
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if p, ok := s.networkProtocols[num]; ok {
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return p
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}
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return nil
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}
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// TransportProtocolInstance returns the protocol instance in the stack for the
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// specified transport protocol. This method is public for protocol implementers
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// and tests to use.
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func (s *Stack) TransportProtocolInstance(num tcpip.TransportProtocolNumber) TransportProtocol {
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if pState, ok := s.transportProtocols[num]; ok {
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return pState.proto
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}
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return nil
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}
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