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nekohasekainekohasekai
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ping: Add gVisor destination
1 parent 12c9fb6 commit 86d9606

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9 files changed

+332
-221
lines changed

9 files changed

+332
-221
lines changed

‎ping/destination_gvisor.go‎

Lines changed: 113 additions & 0 deletions
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//go:build with_gvisor
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package ping
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import (
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"context"
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"net/netip"
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"github.com/sagernet/gvisor/pkg/tcpip"
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"github.com/sagernet/gvisor/pkg/tcpip/adapters/gonet"
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"github.com/sagernet/gvisor/pkg/tcpip/header"
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"github.com/sagernet/gvisor/pkg/tcpip/stack"
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"github.com/sagernet/gvisor/pkg/waiter"
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"github.com/sagernet/sing-tun"
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"github.com/sagernet/sing/common"
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"github.com/sagernet/sing/common/buf"
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E "github.com/sagernet/sing/common/exceptions"
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"github.com/sagernet/sing/common/logger"
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)
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var _ tun.DirectRouteDestination = (*GVisorDestination)(nil)
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type GVisorDestination struct {
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ctx context.Context
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logger logger.ContextLogger
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conn *gonet.TCPConn
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rewriter *Rewriter
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}
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func ConnectGVisor(
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ctx context.Context, logger logger.ContextLogger,
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sourceAddress, destinationAddress netip.Addr,
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routeContext tun.DirectRouteContext,
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stack *stack.Stack,
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bindAddress4, bindAddress6 netip.Addr,
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) (*GVisorDestination, error) {
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var (
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bindAddress tcpip.Address
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wq waiter.Queue
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endpoint tcpip.Endpoint
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gErr tcpip.Error
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)
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if !destinationAddress.Is6() {
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if !bindAddress4.IsValid() {
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return nil, E.New("missing IPv4 interface address")
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}
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bindAddress = tun.AddressFromAddr(bindAddress4)
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endpoint, gErr = stack.NewRawEndpoint(header.ICMPv4ProtocolNumber, header.IPv4ProtocolNumber, &wq, true)
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} else {
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if !bindAddress6.IsValid() {
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return nil, E.New("missing IPv6 interface address")
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}
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bindAddress = tun.AddressFromAddr(bindAddress6)
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endpoint, gErr = stack.NewRawEndpoint(header.ICMPv6ProtocolNumber, header.IPv6ProtocolNumber, &wq, true)
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}
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if gErr != nil {
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return nil, gonet.TranslateNetstackError(gErr)
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}
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gErr = endpoint.Bind(tcpip.FullAddress{
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NIC: 1,
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Addr: bindAddress,
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})
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if gErr != nil {
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return nil, gonet.TranslateNetstackError(gErr)
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}
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gErr = endpoint.Connect(tcpip.FullAddress{
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NIC: 1,
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Addr: tun.AddressFromAddr(destinationAddress),
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})
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if gErr != nil {
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return nil, gonet.TranslateNetstackError(gErr)
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}
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endpoint.SocketOptions().SetHeaderIncluded(true)
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rewriter := NewRewriter(bindAddress4, bindAddress6)
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rewriter.CreateSession(tun.DirectRouteSession{Source: sourceAddress, Destination: destinationAddress}, routeContext)
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destination := &GVisorDestination{
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ctx: ctx,
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logger: logger,
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conn: gonet.NewTCPConn(&wq, endpoint),
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rewriter: rewriter,
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}
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go destination.loopRead()
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return destination, nil
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}
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func (d *GVisorDestination) loopRead() {
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for {
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buffer := buf.NewPacket()
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n, err := d.conn.Read(buffer.FreeBytes())
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if err != nil {
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buffer.Release()
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if !E.IsClosed(err) {
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d.logger.ErrorContext(d.ctx, E.Cause(err, "receive ICMP echo reply"))
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}
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return
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}
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buffer.Truncate(n)
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_, err = d.rewriter.WriteBack(buffer.Bytes())
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if err != nil {
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d.logger.ErrorContext(d.ctx, E.Cause(err, "write ICMP echo reply"))
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}
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buffer.Release()
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}
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}
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func (d *GVisorDestination) WritePacket(packet *buf.Buffer) error {
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d.rewriter.RewritePacket(packet.Bytes())
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return common.Error(d.conn.Write(packet.Bytes()))
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}
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func (d *GVisorDestination) Close() error {
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return d.conn.Close()
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}

‎ping/rewriter.go‎

Lines changed: 142 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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package ping
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import (
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"net/netip"
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"sync"
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"github.com/sagernet/sing-tun"
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"github.com/sagernet/sing-tun/internal/gtcpip/header"
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)
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type Rewriter struct {
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access sync.RWMutex
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sessions map[tun.DirectRouteSession]tun.DirectRouteContext
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source4Address map[uint16]netip.Addr
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source6Address map[uint16]netip.Addr
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inet4Address netip.Addr
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inet6Address netip.Addr
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}
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func NewRewriter(inet4Address netip.Addr, inet6Address netip.Addr) *Rewriter {
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return &Rewriter{
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sessions: make(map[tun.DirectRouteSession]tun.DirectRouteContext),
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inet4Address: inet4Address,
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inet6Address: inet6Address,
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}
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}
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func (m *Rewriter) CreateSession(session tun.DirectRouteSession, context tun.DirectRouteContext) {
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m.access.Lock()
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m.sessions[session] = context
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m.access.Unlock()
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}
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func (m *Rewriter) DeleteSession(session tun.DirectRouteSession) {
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m.access.Lock()
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delete(m.sessions, session)
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m.access.Unlock()
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}
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func (m *Rewriter) RewritePacket(packet []byte) {
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var ipHdr header.Network
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var bindAddr netip.Addr
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switch header.IPVersion(packet) {
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case header.IPv4Version:
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ipHdr = header.IPv4(packet)
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bindAddr = m.inet4Address
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case header.IPv6Version:
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ipHdr = header.IPv6(packet)
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bindAddr = m.inet6Address
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default:
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return
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}
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sourceAddr := ipHdr.SourceAddr()
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ipHdr.SetSourceAddr(bindAddr)
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if ipHdr4, isIPv4 := ipHdr.(header.IPv4); isIPv4 {
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ipHdr4.SetChecksum(0)
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ipHdr4.SetChecksum(^ipHdr4.CalculateChecksum())
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}
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switch ipHdr.TransportProtocol() {
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case header.ICMPv4ProtocolNumber:
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icmpHdr := header.ICMPv4(ipHdr.Payload())
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m.access.Lock()
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m.source4Address[icmpHdr.Ident()] = sourceAddr
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m.access.Lock()
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case header.ICMPv6ProtocolNumber:
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icmpHdr := header.ICMPv6(ipHdr.Payload())
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icmpHdr.SetChecksum(0)
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icmpHdr.SetChecksum(header.ICMPv6Checksum(header.ICMPv6ChecksumParams{
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Header: icmpHdr,
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Src: ipHdr.SourceAddressSlice(),
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Dst: ipHdr.DestinationAddressSlice(),
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}))
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m.access.Lock()
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m.source6Address[icmpHdr.Ident()] = sourceAddr
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m.access.Lock()
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}
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}
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func (m *Rewriter) WriteBack(packet []byte) (bool, error) {
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var ipHdr header.Network
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var routeSession tun.DirectRouteSession
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switch header.IPVersion(packet) {
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case header.IPv4Version:
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ipHdr = header.IPv4(packet)
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routeSession.Destination = ipHdr.SourceAddr()
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case header.IPv6Version:
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ipHdr = header.IPv6(packet)
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routeSession.Destination = ipHdr.SourceAddr()
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default:
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return false, nil
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}
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switch ipHdr.TransportProtocol() {
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case header.ICMPv4ProtocolNumber:
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icmpHdr := header.ICMPv4(ipHdr.Payload())
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m.access.Lock()
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ident := icmpHdr.Ident()
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source, loaded := m.source4Address[ident]
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if !loaded {
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m.access.Unlock()
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return false, nil
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}
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delete(m.source4Address, icmpHdr.Ident())
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m.access.Lock()
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routeSession.Source = source
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case header.ICMPv6ProtocolNumber:
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icmpHdr := header.ICMPv6(ipHdr.Payload())
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m.access.Lock()
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ident := icmpHdr.Ident()
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source, loaded := m.source6Address[ident]
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if !loaded {
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m.access.Unlock()
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return false, nil
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}
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delete(m.source6Address, icmpHdr.Ident())
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m.access.Lock()
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routeSession.Source = source
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default:
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return false, nil
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}
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m.access.RLock()
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context, loaded := m.sessions[routeSession]
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m.access.RUnlock()
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if !loaded {
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return false, nil
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}
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ipHdr.SetDestinationAddr(routeSession.Source)
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if ipHdr4, isIPv4 := ipHdr.(header.IPv4); isIPv4 {
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ipHdr4.SetChecksum(0)
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ipHdr4.SetChecksum(^ipHdr4.CalculateChecksum())
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}
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switch ipHdr.TransportProtocol() {
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case header.ICMPv6ProtocolNumber:
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icmpHdr := header.ICMPv6(ipHdr.Payload())
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icmpHdr.SetChecksum(0)
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icmpHdr.SetChecksum(header.ICMPv6Checksum(header.ICMPv6ChecksumParams{
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Header: icmpHdr,
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Src: ipHdr.SourceAddressSlice(),
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Dst: ipHdr.DestinationAddressSlice(),
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}))
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}
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return true, context.WritePacket(packet)
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}

‎route_direct.go‎

Lines changed: 51 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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package tun
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import (
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"net/netip"
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"time"
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"github.com/sagernet/sing/common"
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"github.com/sagernet/sing/common/buf"
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"github.com/sagernet/sing/contrab/freelru"
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"github.com/sagernet/sing/contrab/maphash"
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)
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type DirectRouteDestination interface {
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WritePacket(packet *buf.Buffer) error
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Close() error
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}
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type DirectRouteSession struct {
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// IPVersion uint8
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// Network uint8
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Source netip.Addr
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Destination netip.Addr
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}
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type DirectRouteMapping struct {
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mapping freelru.Cache[DirectRouteSession, DirectRouteDestination]
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}
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func NewDirectRouteMapping(timeout time.Duration) *DirectRouteMapping {
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mapping := common.Must1(freelru.NewSharded[DirectRouteSession, DirectRouteDestination](1024, maphash.NewHasher[DirectRouteSession]().Hash32))
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mapping.SetOnEvict(func(session DirectRouteSession, action DirectRouteDestination) {
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action.Close()
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})
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mapping.SetLifetime(timeout)
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return &DirectRouteMapping{mapping}
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}
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func (m *DirectRouteMapping) Lookup(session DirectRouteSession, constructor func() (DirectRouteDestination, error)) (DirectRouteDestination, error) {
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var (
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created DirectRouteDestination
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err error
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)
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action, _, ok := m.mapping.GetAndRefreshOrAdd(session, func() (DirectRouteDestination, bool) {
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created, err = constructor()
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return created, err == nil
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})
47+
if !ok {
48+
return nil, err
49+
}
50+
return action, nil
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}

‎route_mapping.go‎

Lines changed: 0 additions & 45 deletions
This file was deleted.

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