Xray-core/proxy/freedom/freedom.go

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package freedom
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//go:generate go run github.com/xtls/xray-core/common/errors/errorgen
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import (
"context"
"crypto/rand"
"io"
"math/big"
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"time"
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"github.com/xtls/xray-core/common"
"github.com/xtls/xray-core/common/buf"
"github.com/xtls/xray-core/common/dice"
"github.com/xtls/xray-core/common/net"
"github.com/xtls/xray-core/common/platform"
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"github.com/xtls/xray-core/common/retry"
"github.com/xtls/xray-core/common/session"
"github.com/xtls/xray-core/common/signal"
"github.com/xtls/xray-core/common/task"
"github.com/xtls/xray-core/core"
"github.com/xtls/xray-core/features/dns"
"github.com/xtls/xray-core/features/policy"
"github.com/xtls/xray-core/features/stats"
"github.com/xtls/xray-core/proxy"
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"github.com/xtls/xray-core/transport"
"github.com/xtls/xray-core/transport/internet"
"github.com/xtls/xray-core/transport/internet/stat"
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)
var useSplice bool
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func init() {
common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
h := new(Handler)
if err := core.RequireFeatures(ctx, func(pm policy.Manager, d dns.Client) error {
return h.Init(config.(*Config), pm, d)
}); err != nil {
return nil, err
}
return h, nil
}))
const defaultFlagValue = "NOT_DEFINED_AT_ALL"
value := platform.NewEnvFlag(platform.UseFreedomSplice).GetValue(func() string { return defaultFlagValue })
switch value {
case defaultFlagValue, "auto", "enable":
useSplice = true
}
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}
// Handler handles Freedom connections.
type Handler struct {
policyManager policy.Manager
dns dns.Client
config *Config
}
// Init initializes the Handler with necessary parameters.
func (h *Handler) Init(config *Config, pm policy.Manager, d dns.Client) error {
h.config = config
h.policyManager = pm
h.dns = d
return nil
}
func (h *Handler) policy() policy.Session {
p := h.policyManager.ForLevel(h.config.UserLevel)
if h.config.Timeout > 0 && h.config.UserLevel == 0 {
p.Timeouts.ConnectionIdle = time.Duration(h.config.Timeout) * time.Second
}
return p
}
func (h *Handler) resolveIP(ctx context.Context, domain string, localAddr net.Address) net.Address {
ips, err := h.dns.LookupIP(domain, dns.IPOption{
IPv4Enable: (localAddr == nil || localAddr.Family().IsIPv4()) && h.config.preferIP4(),
IPv6Enable: (localAddr == nil || localAddr.Family().IsIPv6()) && h.config.preferIP6(),
})
{ // Resolve fallback
if (len(ips) == 0 || err != nil) && h.config.hasFallback() && localAddr == nil {
ips, err = h.dns.LookupIP(domain, dns.IPOption{
IPv4Enable: h.config.fallbackIP4(),
IPv6Enable: h.config.fallbackIP6(),
})
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}
}
if err != nil {
newError("failed to get IP address for domain ", domain).Base(err).WriteToLog(session.ExportIDToError(ctx))
}
if len(ips) == 0 {
return nil
}
return net.IPAddress(ips[dice.Roll(len(ips))])
}
func isValidAddress(addr *net.IPOrDomain) bool {
if addr == nil {
return false
}
a := addr.AsAddress()
return a != net.AnyIP
}
// Process implements proxy.Outbound.
func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer internet.Dialer) error {
outbound := session.OutboundFromContext(ctx)
if outbound == nil || !outbound.Target.IsValid() {
return newError("target not specified.")
}
outbound.Name = "freedom"
inbound := session.InboundFromContext(ctx)
if inbound != nil {
inbound.SetCanSpliceCopy(1)
}
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destination := outbound.Target
UDPOverride := net.UDPDestination(nil, 0)
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if h.config.DestinationOverride != nil {
server := h.config.DestinationOverride.Server
if isValidAddress(server.Address) {
destination.Address = server.Address.AsAddress()
UDPOverride.Address = destination.Address
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}
if server.Port != 0 {
destination.Port = net.Port(server.Port)
UDPOverride.Port = destination.Port
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}
}
input := link.Reader
output := link.Writer
var conn stat.Connection
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err := retry.ExponentialBackoff(5, 100).On(func() error {
dialDest := destination
if h.config.hasStrategy() && dialDest.Address.Family().IsDomain() {
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ip := h.resolveIP(ctx, dialDest.Address.Domain(), dialer.Address())
if ip != nil {
dialDest = net.Destination{
Network: dialDest.Network,
Address: ip,
Port: dialDest.Port,
}
newError("dialing to ", dialDest).WriteToLog(session.ExportIDToError(ctx))
} else if h.config.forceIP() {
return dns.ErrEmptyResponse
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}
}
rawConn, err := dialer.Dial(ctx, dialDest)
if err != nil {
return err
}
conn = rawConn
return nil
})
if err != nil {
return newError("failed to open connection to ", destination).Base(err)
}
defer conn.Close()
newError("connection opened to ", destination, ", local endpoint ", conn.LocalAddr(), ", remote endpoint ", conn.RemoteAddr()).WriteToLog(session.ExportIDToError(ctx))
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var newCtx context.Context
var newCancel context.CancelFunc
if session.TimeoutOnlyFromContext(ctx) {
newCtx, newCancel = context.WithCancel(context.Background())
}
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plcy := h.policy()
ctx, cancel := context.WithCancel(ctx)
timer := signal.CancelAfterInactivity(ctx, func() {
cancel()
if newCancel != nil {
newCancel()
}
}, plcy.Timeouts.ConnectionIdle)
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requestDone := func() error {
defer timer.SetTimeout(plcy.Timeouts.DownlinkOnly)
var writer buf.Writer
if destination.Network == net.Network_TCP {
if h.config.Fragment != nil {
newError("FRAGMENT", h.config.Fragment.PacketsFrom, h.config.Fragment.PacketsTo, h.config.Fragment.LengthMin, h.config.Fragment.LengthMax,
h.config.Fragment.IntervalMin, h.config.Fragment.IntervalMax).AtDebug().WriteToLog(session.ExportIDToError(ctx))
writer = buf.NewWriter(&FragmentWriter{
fragment: h.config.Fragment,
writer: conn,
})
} else {
writer = buf.NewWriter(conn)
}
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} else {
writer = NewPacketWriter(conn, h, ctx, UDPOverride)
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}
if err := buf.Copy(input, writer, buf.UpdateActivity(timer)); err != nil {
return newError("failed to process request").Base(err)
}
return nil
}
responseDone := func() error {
defer timer.SetTimeout(plcy.Timeouts.UplinkOnly)
if destination.Network == net.Network_TCP {
var writeConn net.Conn
if inbound := session.InboundFromContext(ctx); inbound != nil && inbound.Conn != nil && useSplice {
writeConn = inbound.Conn
}
return proxy.CopyRawConnIfExist(ctx, conn, writeConn, link.Writer, timer)
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}
reader := NewPacketReader(conn, UDPOverride)
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if err := buf.Copy(reader, output, buf.UpdateActivity(timer)); err != nil {
return newError("failed to process response").Base(err)
}
return nil
}
if newCtx != nil {
ctx = newCtx
}
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if err := task.Run(ctx, requestDone, task.OnSuccess(responseDone, task.Close(output))); err != nil {
return newError("connection ends").Base(err)
}
return nil
}
func NewPacketReader(conn net.Conn, UDPOverride net.Destination) buf.Reader {
iConn := conn
statConn, ok := iConn.(*stat.CounterConnection)
if ok {
iConn = statConn.Connection
}
var counter stats.Counter
if statConn != nil {
counter = statConn.ReadCounter
}
if c, ok := iConn.(*internet.PacketConnWrapper); ok && UDPOverride.Address == nil && UDPOverride.Port == 0 {
return &PacketReader{
PacketConnWrapper: c,
Counter: counter,
}
}
return &buf.PacketReader{Reader: conn}
}
type PacketReader struct {
*internet.PacketConnWrapper
stats.Counter
}
func (r *PacketReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
b := buf.New()
b.Resize(0, buf.Size)
n, d, err := r.PacketConnWrapper.ReadFrom(b.Bytes())
if err != nil {
b.Release()
return nil, err
}
b.Resize(0, int32(n))
b.UDP = &net.Destination{
Address: net.IPAddress(d.(*net.UDPAddr).IP),
Port: net.Port(d.(*net.UDPAddr).Port),
Network: net.Network_UDP,
}
if r.Counter != nil {
r.Counter.Add(int64(n))
}
return buf.MultiBuffer{b}, nil
}
func NewPacketWriter(conn net.Conn, h *Handler, ctx context.Context, UDPOverride net.Destination) buf.Writer {
iConn := conn
statConn, ok := iConn.(*stat.CounterConnection)
if ok {
iConn = statConn.Connection
}
var counter stats.Counter
if statConn != nil {
counter = statConn.WriteCounter
}
if c, ok := iConn.(*internet.PacketConnWrapper); ok {
return &PacketWriter{
PacketConnWrapper: c,
Counter: counter,
Handler: h,
Context: ctx,
UDPOverride: UDPOverride,
}
}
return &buf.SequentialWriter{Writer: conn}
}
type PacketWriter struct {
*internet.PacketConnWrapper
stats.Counter
*Handler
context.Context
UDPOverride net.Destination
}
func (w *PacketWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
for {
mb2, b := buf.SplitFirst(mb)
mb = mb2
if b == nil {
break
}
var n int
var err error
if b.UDP != nil {
if w.UDPOverride.Address != nil {
b.UDP.Address = w.UDPOverride.Address
}
if w.UDPOverride.Port != 0 {
b.UDP.Port = w.UDPOverride.Port
}
if w.Handler.config.hasStrategy() && b.UDP.Address.Family().IsDomain() {
ip := w.Handler.resolveIP(w.Context, b.UDP.Address.Domain(), nil)
if ip != nil {
b.UDP.Address = ip
}
}
destAddr, _ := net.ResolveUDPAddr("udp", b.UDP.NetAddr())
if destAddr == nil {
b.Release()
continue
}
n, err = w.PacketConnWrapper.WriteTo(b.Bytes(), destAddr)
} else {
n, err = w.PacketConnWrapper.Write(b.Bytes())
}
b.Release()
if err != nil {
buf.ReleaseMulti(mb)
return err
}
if w.Counter != nil {
w.Counter.Add(int64(n))
}
}
return nil
}
type FragmentWriter struct {
fragment *Fragment
writer io.Writer
count uint64
}
func (f *FragmentWriter) Write(b []byte) (int, error) {
f.count++
if f.fragment.PacketsFrom == 0 && f.fragment.PacketsTo == 1 {
if f.count != 1 || len(b) <= 5 || b[0] != 22 {
return f.writer.Write(b)
}
recordLen := 5 + ((int(b[3]) << 8) | int(b[4]))
data := b[5:recordLen]
buf := make([]byte, 1024)
for from := 0; ; {
to := from + int(randBetween(int64(f.fragment.LengthMin), int64(f.fragment.LengthMax)))
if to > len(data) {
to = len(data)
}
copy(buf[:3], b)
copy(buf[5:], data[from:to])
l := to - from
from = to
buf[3] = byte(l >> 8)
buf[4] = byte(l)
_, err := f.writer.Write(buf[:5+l])
time.Sleep(time.Duration(randBetween(int64(f.fragment.IntervalMin), int64(f.fragment.IntervalMax))) * time.Millisecond)
if err != nil {
return 0, err
}
if from == len(data) {
if len(b) > recordLen {
n, err := f.writer.Write(b[recordLen:])
if err != nil {
return recordLen + n, err
}
}
return len(b), nil
}
}
}
if f.fragment.PacketsFrom != 0 && (f.count < f.fragment.PacketsFrom || f.count > f.fragment.PacketsTo) {
return f.writer.Write(b)
}
for from := 0; ; {
to := from + int(randBetween(int64(f.fragment.LengthMin), int64(f.fragment.LengthMax)))
if to > len(b) {
to = len(b)
}
n, err := f.writer.Write(b[from:to])
from += n
time.Sleep(time.Duration(randBetween(int64(f.fragment.IntervalMin), int64(f.fragment.IntervalMax))) * time.Millisecond)
if err != nil {
return from, err
}
if from >= len(b) {
return from, nil
}
}
}
// stolen from github.com/xtls/xray-core/transport/internet/reality
func randBetween(left int64, right int64) int64 {
if left == right {
return left
}
bigInt, _ := rand.Int(rand.Reader, big.NewInt(right-left))
return left + bigInt.Int64()
}