sing-box/inbound/tun.go

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//go:build !no_tun
package inbound
import (
"context"
"net"
"net/netip"
"os"
"runtime"
"strconv"
"strings"
"github.com/sagernet/sing-box/adapter"
C "github.com/sagernet/sing-box/constant"
"github.com/sagernet/sing-box/log"
"github.com/sagernet/sing-box/option"
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"github.com/sagernet/sing-dns"
"github.com/sagernet/sing-tun"
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E "github.com/sagernet/sing/common/exceptions"
F "github.com/sagernet/sing/common/format"
M "github.com/sagernet/sing/common/metadata"
N "github.com/sagernet/sing/common/network"
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"github.com/sagernet/sing/common/task"
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)
var _ adapter.Inbound = (*Tun)(nil)
type Tun struct {
tag string
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ctx context.Context
router adapter.Router
logger log.Logger
inboundOptions option.InboundOptions
tunName string
tunMTU uint32
inet4Address netip.Prefix
inet6Address netip.Prefix
autoRoute bool
hijackDNS bool
tunFd uintptr
tun *tun.GVisorTun
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}
func NewTun(ctx context.Context, router adapter.Router, logger log.Logger, tag string, options option.TunInboundOptions) (*Tun, error) {
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tunName := options.InterfaceName
if tunName == "" {
tunName = mkInterfaceName()
}
tunMTU := options.MTU
if tunMTU == 0 {
tunMTU = 1500
}
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return &Tun{
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tag: tag,
ctx: ctx,
router: router,
logger: logger,
inboundOptions: options.InboundOptions,
tunName: tunName,
tunMTU: tunMTU,
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inet4Address: options.Inet4Address.Build(),
inet6Address: options.Inet6Address.Build(),
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autoRoute: options.AutoRoute,
hijackDNS: options.HijackDNS,
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}, nil
}
func (t *Tun) Type() string {
return C.TypeTun
}
func (t *Tun) Tag() string {
return t.tag
}
func (t *Tun) Start() error {
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tunFd, err := tun.Open(t.tunName)
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if err != nil {
return E.Cause(err, "create tun interface")
}
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err = tun.Configure(t.tunName, t.inet4Address, t.inet6Address, t.tunMTU, t.autoRoute)
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if err != nil {
return E.Cause(err, "configure tun interface")
}
t.tunFd = tunFd
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t.tun = tun.NewGVisor(t.ctx, tunFd, t.tunMTU, t)
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err = t.tun.Start()
if err != nil {
return err
}
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t.logger.Info("started at ", t.tunName)
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return nil
}
func (t *Tun) Close() error {
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err := tun.UnConfigure(t.tunName, t.inet4Address, t.inet6Address, t.autoRoute)
if err != nil {
return err
}
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return E.Errors(
t.tun.Close(),
os.NewFile(t.tunFd, "tun").Close(),
)
}
func (t *Tun) NewConnection(ctx context.Context, conn net.Conn, upstreamMetadata M.Metadata) error {
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ctx = log.ContextWithID(ctx)
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var metadata adapter.InboundContext
metadata.Inbound = t.tag
metadata.Network = C.NetworkTCP
metadata.Source = upstreamMetadata.Source
metadata.Destination = upstreamMetadata.Destination
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metadata.SniffEnabled = t.inboundOptions.SniffEnabled
metadata.SniffOverrideDestination = t.inboundOptions.SniffOverrideDestination
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metadata.DomainStrategy = dns.DomainStrategy(t.inboundOptions.DomainStrategy)
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if t.hijackDNS && upstreamMetadata.Destination.Port == 53 {
return task.Run(ctx, func() error {
return NewDNSConnection(ctx, t.router, t.logger, conn, metadata)
})
}
t.logger.WithContext(ctx).Info("inbound connection from ", metadata.Source)
t.logger.WithContext(ctx).Info("inbound connection to ", metadata.Destination)
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return t.router.RouteConnection(ctx, conn, metadata)
}
func (t *Tun) NewPacketConnection(ctx context.Context, conn N.PacketConn, upstreamMetadata M.Metadata) error {
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ctx = log.ContextWithID(ctx)
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var metadata adapter.InboundContext
metadata.Inbound = t.tag
metadata.Network = C.NetworkUDP
metadata.Source = upstreamMetadata.Source
metadata.Destination = upstreamMetadata.Destination
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metadata.SniffEnabled = t.inboundOptions.SniffEnabled
metadata.SniffOverrideDestination = t.inboundOptions.SniffOverrideDestination
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metadata.DomainStrategy = dns.DomainStrategy(t.inboundOptions.DomainStrategy)
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if t.hijackDNS && upstreamMetadata.Destination.Port == 53 {
return task.Run(ctx, func() error {
return NewDNSPacketConnection(ctx, t.router, t.logger, conn, metadata)
})
}
t.logger.WithContext(ctx).Info("inbound packet connection from ", metadata.Source)
t.logger.WithContext(ctx).Info("inbound packet connection to ", metadata.Destination)
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return t.router.RoutePacketConnection(ctx, conn, metadata)
}
func (t *Tun) NewError(ctx context.Context, err error) {
NewError(t.logger, ctx, err)
}
func mkInterfaceName() (tunName string) {
switch runtime.GOOS {
case "darwin":
tunName = "utun"
default:
tunName = "tun"
}
interfaces, err := net.Interfaces()
if err != nil {
return
}
var tunIndex int
for _, netInterface := range interfaces {
if strings.HasPrefix(netInterface.Name, tunName) {
index, parseErr := strconv.ParseInt(netInterface.Name[len(tunName):], 10, 16)
if parseErr == nil {
tunIndex = int(index) + 1
}
}
}
tunName = F.ToString(tunName, tunIndex)
return
}