sing-tun/gvisor.go
2023-03-24 16:22:20 +08:00

271 lines
8.4 KiB
Go

//go:build with_gvisor
package tun
import (
"context"
"net"
"syscall"
"time"
"github.com/sagernet/sing/common/bufio"
"github.com/sagernet/sing/common/canceler"
E "github.com/sagernet/sing/common/exceptions"
"github.com/sagernet/sing/common/logger"
M "github.com/sagernet/sing/common/metadata"
"gvisor.dev/gvisor/pkg/tcpip"
"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
"gvisor.dev/gvisor/pkg/tcpip/header"
"gvisor.dev/gvisor/pkg/tcpip/network/ipv4"
"gvisor.dev/gvisor/pkg/tcpip/network/ipv6"
"gvisor.dev/gvisor/pkg/tcpip/stack"
"gvisor.dev/gvisor/pkg/tcpip/transport/icmp"
"gvisor.dev/gvisor/pkg/tcpip/transport/tcp"
"gvisor.dev/gvisor/pkg/tcpip/transport/udp"
"gvisor.dev/gvisor/pkg/waiter"
)
const WithGVisor = true
const defaultNIC tcpip.NICID = 1
type GVisor struct {
ctx context.Context
tun GVisorTun
tunMtu uint32
endpointIndependentNat bool
udpTimeout int64
router Router
handler Handler
logger logger.Logger
stack *stack.Stack
endpoint stack.LinkEndpoint
routeMapping *RouteMapping
}
type GVisorTun interface {
Tun
NewEndpoint() (stack.LinkEndpoint, error)
}
func NewGVisor(
options StackOptions,
) (Stack, error) {
gTun, isGTun := options.Tun.(GVisorTun)
if !isGTun {
return nil, E.New("gVisor stack is unsupported on current platform")
}
return &GVisor{
ctx: options.Context,
tun: gTun,
tunMtu: options.MTU,
endpointIndependentNat: options.EndpointIndependentNat,
udpTimeout: options.UDPTimeout,
router: options.Router,
handler: options.Handler,
logger: options.Logger,
routeMapping: NewRouteMapping(options.UDPTimeout),
}, nil
}
func (t *GVisor) Start() error {
linkEndpoint, err := t.tun.NewEndpoint()
if err != nil {
return err
}
ipStack := stack.New(stack.Options{
NetworkProtocols: []stack.NetworkProtocolFactory{
ipv4.NewProtocol,
ipv6.NewProtocol,
},
TransportProtocols: []stack.TransportProtocolFactory{
tcp.NewProtocol,
udp.NewProtocol,
icmp.NewProtocol4,
icmp.NewProtocol6,
},
})
tErr := ipStack.CreateNIC(defaultNIC, linkEndpoint)
if tErr != nil {
return E.New("create nic: ", wrapStackError(tErr))
}
ipStack.SetRouteTable([]tcpip.Route{
{Destination: header.IPv4EmptySubnet, NIC: defaultNIC},
{Destination: header.IPv6EmptySubnet, NIC: defaultNIC},
})
ipStack.SetSpoofing(defaultNIC, true)
ipStack.SetPromiscuousMode(defaultNIC, true)
bufSize := 20 * 1024
ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &tcpip.TCPReceiveBufferSizeRangeOption{
Min: 1,
Default: bufSize,
Max: bufSize,
})
ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &tcpip.TCPSendBufferSizeRangeOption{
Min: 1,
Default: bufSize,
Max: bufSize,
})
sOpt := tcpip.TCPSACKEnabled(true)
ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &sOpt)
mOpt := tcpip.TCPModerateReceiveBufferOption(true)
ipStack.SetTransportProtocolOption(tcp.ProtocolNumber, &mOpt)
tcpForwarder := tcp.NewForwarder(ipStack, 0, 1024, func(r *tcp.ForwarderRequest) {
var wq waiter.Queue
handshakeCtx, cancel := context.WithCancel(context.Background())
go func() {
select {
case <-t.ctx.Done():
wq.Notify(wq.Events())
case <-handshakeCtx.Done():
}
}()
endpoint, err := r.CreateEndpoint(&wq)
cancel()
if err != nil {
r.Complete(true)
return
}
r.Complete(false)
endpoint.SocketOptions().SetKeepAlive(true)
keepAliveIdle := tcpip.KeepaliveIdleOption(15 * time.Second)
endpoint.SetSockOpt(&keepAliveIdle)
keepAliveInterval := tcpip.KeepaliveIntervalOption(15 * time.Second)
endpoint.SetSockOpt(&keepAliveInterval)
tcpConn := gonet.NewTCPConn(&wq, endpoint)
lAddr := tcpConn.RemoteAddr()
rAddr := tcpConn.LocalAddr()
if lAddr == nil || rAddr == nil {
tcpConn.Close()
return
}
go func() {
var metadata M.Metadata
metadata.Source = M.SocksaddrFromNet(lAddr)
metadata.Destination = M.SocksaddrFromNet(rAddr)
hErr := t.handler.NewConnection(t.ctx, &gTCPConn{tcpConn}, metadata)
if hErr != nil {
endpoint.Abort()
}
}()
})
ipStack.SetTransportProtocolHandler(tcp.ProtocolNumber, func(id stack.TransportEndpointID, buffer *stack.PacketBuffer) bool {
if t.router != nil {
var routeSession RouteSession
routeSession.Network = syscall.IPPROTO_TCP
var ipHdr header.Network
if buffer.NetworkProtocolNumber == header.IPv4ProtocolNumber {
routeSession.IPVersion = 4
ipHdr = header.IPv4(buffer.NetworkHeader().Slice())
} else {
routeSession.IPVersion = 6
ipHdr = header.IPv6(buffer.NetworkHeader().Slice())
}
tcpHdr := header.TCP(buffer.TransportHeader().Slice())
routeSession.Source = M.AddrPortFrom(net.IP(ipHdr.SourceAddress()), tcpHdr.SourcePort())
routeSession.Destination = M.AddrPortFrom(net.IP(ipHdr.DestinationAddress()), tcpHdr.DestinationPort())
action := t.routeMapping.Lookup(routeSession, func() RouteAction {
if routeSession.IPVersion == 4 {
return t.router.RouteConnection(routeSession, &systemTCPDirectPacketWriter4{t.tun, routeSession.Source})
} else {
return t.router.RouteConnection(routeSession, &systemTCPDirectPacketWriter6{t.tun, routeSession.Source})
}
})
switch actionType := action.(type) {
case *ActionBlock:
// TODO: send icmp unreachable
return true
case *ActionDirect:
buffer.IncRef()
err = actionType.WritePacketBuffer(buffer)
if err != nil {
t.logger.Trace("route gvisor tcp packet: ", err)
}
return true
}
}
return tcpForwarder.HandlePacket(id, buffer)
})
if !t.endpointIndependentNat {
udpForwarder := udp.NewForwarder(ipStack, func(request *udp.ForwarderRequest) {
var wq waiter.Queue
endpoint, err := request.CreateEndpoint(&wq)
if err != nil {
return
}
udpConn := gonet.NewUDPConn(ipStack, &wq, endpoint)
lAddr := udpConn.RemoteAddr()
rAddr := udpConn.LocalAddr()
if lAddr == nil || rAddr == nil {
endpoint.Abort()
return
}
go func() {
var metadata M.Metadata
metadata.Source = M.SocksaddrFromNet(lAddr)
metadata.Destination = M.SocksaddrFromNet(rAddr)
ctx, conn := canceler.NewPacketConn(t.ctx, bufio.NewPacketConn(&bufio.UnbindPacketConn{ExtendedConn: bufio.NewExtendedConn(&gUDPConn{udpConn}), Addr: M.SocksaddrFromNet(rAddr)}), time.Duration(t.udpTimeout)*time.Second)
hErr := t.handler.NewPacketConnection(ctx, conn, metadata)
if hErr != nil {
endpoint.Abort()
}
}()
})
ipStack.SetTransportProtocolHandler(udp.ProtocolNumber, func(id stack.TransportEndpointID, buffer *stack.PacketBuffer) bool {
if t.router != nil {
var routeSession RouteSession
routeSession.Network = syscall.IPPROTO_UDP
var ipHdr header.Network
if buffer.NetworkProtocolNumber == header.IPv4ProtocolNumber {
routeSession.IPVersion = 4
ipHdr = header.IPv4(buffer.NetworkHeader().Slice())
} else {
routeSession.IPVersion = 6
ipHdr = header.IPv6(buffer.NetworkHeader().Slice())
}
udpHdr := header.UDP(buffer.TransportHeader().Slice())
routeSession.Source = M.AddrPortFrom(net.IP(ipHdr.SourceAddress()), udpHdr.SourcePort())
routeSession.Destination = M.AddrPortFrom(net.IP(ipHdr.DestinationAddress()), udpHdr.DestinationPort())
action := t.routeMapping.Lookup(routeSession, func() RouteAction {
if routeSession.IPVersion == 4 {
return t.router.RouteConnection(routeSession, &systemUDPDirectPacketWriter4{t.tun, routeSession.Source})
} else {
return t.router.RouteConnection(routeSession, &systemUDPDirectPacketWriter6{t.tun, routeSession.Source})
}
})
switch actionType := action.(type) {
case *ActionBlock:
// TODO: send icmp unreachable
return true
case *ActionDirect:
buffer.IncRef()
err = actionType.WritePacketBuffer(buffer)
if err != nil {
t.logger.Trace("route gvisor udp packet: ", err)
}
return true
}
}
return udpForwarder.HandlePacket(id, buffer)
})
} else {
ipStack.SetTransportProtocolHandler(udp.ProtocolNumber, NewUDPForwarder(t.ctx, ipStack, t.handler, t.udpTimeout).HandlePacket)
}
t.stack = ipStack
t.endpoint = linkEndpoint
return nil
}
func (t *GVisor) Close() error {
t.endpoint.Attach(nil)
t.stack.Close()
for _, endpoint := range t.stack.CleanupEndpoints() {
endpoint.Abort()
}
return nil
}