mirror of
https://github.com/XTLS/Xray-core.git
synced 2024-12-22 19:33:32 +02:00
460 lines
12 KiB
Go
460 lines
12 KiB
Go
package freedom
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//go:generate go run github.com/xtls/xray-core/common/errors/errorgen
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import (
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"context"
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"crypto/rand"
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"io"
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"math/big"
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"time"
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"github.com/pires/go-proxyproto"
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"github.com/xtls/xray-core/common"
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"github.com/xtls/xray-core/common/buf"
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"github.com/xtls/xray-core/common/dice"
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"github.com/xtls/xray-core/common/errors"
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"github.com/xtls/xray-core/common/net"
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"github.com/xtls/xray-core/common/platform"
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"github.com/xtls/xray-core/common/retry"
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"github.com/xtls/xray-core/common/session"
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"github.com/xtls/xray-core/common/signal"
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"github.com/xtls/xray-core/common/task"
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"github.com/xtls/xray-core/core"
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"github.com/xtls/xray-core/features/dns"
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"github.com/xtls/xray-core/features/policy"
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"github.com/xtls/xray-core/features/stats"
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"github.com/xtls/xray-core/proxy"
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"github.com/xtls/xray-core/transport"
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"github.com/xtls/xray-core/transport/internet"
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"github.com/xtls/xray-core/transport/internet/stat"
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"github.com/xtls/xray-core/transport/internet/tls"
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)
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var useSplice bool
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func init() {
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common.Must(common.RegisterConfig((*Config)(nil), func(ctx context.Context, config interface{}) (interface{}, error) {
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h := new(Handler)
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if err := core.RequireFeatures(ctx, func(pm policy.Manager, d dns.Client) error {
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return h.Init(config.(*Config), pm, d)
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}); err != nil {
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return nil, err
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}
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return h, nil
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}))
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const defaultFlagValue = "NOT_DEFINED_AT_ALL"
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value := platform.NewEnvFlag(platform.UseFreedomSplice).GetValue(func() string { return defaultFlagValue })
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switch value {
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case defaultFlagValue, "auto", "enable":
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useSplice = true
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}
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}
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// Handler handles Freedom connections.
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type Handler struct {
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policyManager policy.Manager
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dns dns.Client
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config *Config
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}
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// Init initializes the Handler with necessary parameters.
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func (h *Handler) Init(config *Config, pm policy.Manager, d dns.Client) error {
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h.config = config
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h.policyManager = pm
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h.dns = d
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return nil
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}
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func (h *Handler) policy() policy.Session {
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p := h.policyManager.ForLevel(h.config.UserLevel)
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if h.config.Timeout > 0 && h.config.UserLevel == 0 {
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p.Timeouts.ConnectionIdle = time.Duration(h.config.Timeout) * time.Second
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}
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return p
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}
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func (h *Handler) resolveIP(ctx context.Context, domain string, localAddr net.Address) net.Address {
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ips, err := h.dns.LookupIP(domain, dns.IPOption{
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IPv4Enable: (localAddr == nil || localAddr.Family().IsIPv4()) && h.config.preferIP4(),
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IPv6Enable: (localAddr == nil || localAddr.Family().IsIPv6()) && h.config.preferIP6(),
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})
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{ // Resolve fallback
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if (len(ips) == 0 || err != nil) && h.config.hasFallback() && localAddr == nil {
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ips, err = h.dns.LookupIP(domain, dns.IPOption{
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IPv4Enable: h.config.fallbackIP4(),
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IPv6Enable: h.config.fallbackIP6(),
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})
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}
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}
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if err != nil {
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errors.LogInfoInner(ctx, err, "failed to get IP address for domain ", domain)
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}
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if len(ips) == 0 {
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return nil
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}
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return net.IPAddress(ips[dice.Roll(len(ips))])
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}
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func isValidAddress(addr *net.IPOrDomain) bool {
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if addr == nil {
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return false
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}
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a := addr.AsAddress()
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return a != net.AnyIP
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}
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// Process implements proxy.Outbound.
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func (h *Handler) Process(ctx context.Context, link *transport.Link, dialer internet.Dialer) error {
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outbounds := session.OutboundsFromContext(ctx)
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ob := outbounds[len(outbounds)-1]
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if !ob.Target.IsValid() {
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return errors.New("target not specified.")
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}
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ob.Name = "freedom"
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ob.CanSpliceCopy = 1
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inbound := session.InboundFromContext(ctx)
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destination := ob.Target
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UDPOverride := net.UDPDestination(nil, 0)
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if h.config.DestinationOverride != nil {
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server := h.config.DestinationOverride.Server
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if isValidAddress(server.Address) {
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destination.Address = server.Address.AsAddress()
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UDPOverride.Address = destination.Address
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}
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if server.Port != 0 {
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destination.Port = net.Port(server.Port)
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UDPOverride.Port = destination.Port
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}
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}
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input := link.Reader
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output := link.Writer
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var conn stat.Connection
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err := retry.ExponentialBackoff(5, 100).On(func() error {
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dialDest := destination
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if h.config.hasStrategy() && dialDest.Address.Family().IsDomain() {
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ip := h.resolveIP(ctx, dialDest.Address.Domain(), dialer.Address())
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if ip != nil {
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dialDest = net.Destination{
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Network: dialDest.Network,
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Address: ip,
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Port: dialDest.Port,
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}
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errors.LogInfo(ctx, "dialing to ", dialDest)
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} else if h.config.forceIP() {
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return dns.ErrEmptyResponse
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}
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}
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rawConn, err := dialer.Dial(ctx, dialDest)
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if err != nil {
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return err
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}
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if h.config.ProxyProtocol > 0 && h.config.ProxyProtocol <= 2 {
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version := byte(h.config.ProxyProtocol)
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srcAddr := inbound.Source.RawNetAddr()
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dstAddr := rawConn.RemoteAddr()
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header := proxyproto.HeaderProxyFromAddrs(version, srcAddr, dstAddr)
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if _, err = header.WriteTo(rawConn); err != nil {
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rawConn.Close()
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return err
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}
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}
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conn = rawConn
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return nil
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})
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if err != nil {
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return errors.New("failed to open connection to ", destination).Base(err)
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}
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defer conn.Close()
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errors.LogInfo(ctx, "connection opened to ", destination, ", local endpoint ", conn.LocalAddr(), ", remote endpoint ", conn.RemoteAddr())
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var newCtx context.Context
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var newCancel context.CancelFunc
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if session.TimeoutOnlyFromContext(ctx) {
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newCtx, newCancel = context.WithCancel(context.Background())
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}
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plcy := h.policy()
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ctx, cancel := context.WithCancel(ctx)
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timer := signal.CancelAfterInactivity(ctx, func() {
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cancel()
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if newCancel != nil {
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newCancel()
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}
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}, plcy.Timeouts.ConnectionIdle)
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requestDone := func() error {
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defer timer.SetTimeout(plcy.Timeouts.DownlinkOnly)
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var writer buf.Writer
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if destination.Network == net.Network_TCP {
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if h.config.Fragment != nil {
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errors.LogDebug(ctx, "FRAGMENT", h.config.Fragment.PacketsFrom, h.config.Fragment.PacketsTo, h.config.Fragment.LengthMin, h.config.Fragment.LengthMax,
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h.config.Fragment.IntervalMin, h.config.Fragment.IntervalMax)
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writer = buf.NewWriter(&FragmentWriter{
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fragment: h.config.Fragment,
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writer: conn,
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})
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} else {
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writer = buf.NewWriter(conn)
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}
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} else {
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writer = NewPacketWriter(conn, h, ctx, UDPOverride)
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}
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if err := buf.Copy(input, writer, buf.UpdateActivity(timer)); err != nil {
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return errors.New("failed to process request").Base(err)
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}
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return nil
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}
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responseDone := func() error {
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defer timer.SetTimeout(plcy.Timeouts.UplinkOnly)
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if destination.Network == net.Network_TCP {
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var writeConn net.Conn
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var inTimer *signal.ActivityTimer
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if inbound := session.InboundFromContext(ctx); inbound != nil && inbound.Conn != nil && useSplice {
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writeConn = inbound.Conn
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inTimer = inbound.Timer
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}
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if !isTLSConn(conn) { // it would be tls conn in special use case of MITM, we need to let link handle traffic
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return proxy.CopyRawConnIfExist(ctx, conn, writeConn, link.Writer, timer, inTimer)
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}
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}
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var reader buf.Reader
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if destination.Network == net.Network_TCP {
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reader = buf.NewReader(conn)
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} else {
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reader = NewPacketReader(conn, UDPOverride)
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}
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if err := buf.Copy(reader, output, buf.UpdateActivity(timer)); err != nil {
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return errors.New("failed to process response").Base(err)
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}
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return nil
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}
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if newCtx != nil {
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ctx = newCtx
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}
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if err := task.Run(ctx, requestDone, task.OnSuccess(responseDone, task.Close(output))); err != nil {
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return errors.New("connection ends").Base(err)
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}
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return nil
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}
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func isTLSConn(conn stat.Connection) bool {
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if conn != nil {
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statConn, ok := conn.(*stat.CounterConnection)
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if ok {
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conn = statConn.Connection
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}
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if _, ok := conn.(*tls.Conn); ok {
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return true
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}
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}
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return false
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}
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func NewPacketReader(conn net.Conn, UDPOverride net.Destination) buf.Reader {
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iConn := conn
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statConn, ok := iConn.(*stat.CounterConnection)
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if ok {
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iConn = statConn.Connection
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}
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var counter stats.Counter
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if statConn != nil {
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counter = statConn.ReadCounter
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}
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if c, ok := iConn.(*internet.PacketConnWrapper); ok && UDPOverride.Address == nil && UDPOverride.Port == 0 {
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return &PacketReader{
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PacketConnWrapper: c,
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Counter: counter,
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}
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}
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return &buf.PacketReader{Reader: conn}
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}
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type PacketReader struct {
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*internet.PacketConnWrapper
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stats.Counter
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}
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func (r *PacketReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
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b := buf.New()
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b.Resize(0, buf.Size)
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n, d, err := r.PacketConnWrapper.ReadFrom(b.Bytes())
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if err != nil {
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b.Release()
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return nil, err
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}
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b.Resize(0, int32(n))
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b.UDP = &net.Destination{
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Address: net.IPAddress(d.(*net.UDPAddr).IP),
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Port: net.Port(d.(*net.UDPAddr).Port),
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Network: net.Network_UDP,
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}
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if r.Counter != nil {
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r.Counter.Add(int64(n))
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}
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return buf.MultiBuffer{b}, nil
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}
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func NewPacketWriter(conn net.Conn, h *Handler, ctx context.Context, UDPOverride net.Destination) buf.Writer {
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iConn := conn
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statConn, ok := iConn.(*stat.CounterConnection)
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if ok {
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iConn = statConn.Connection
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}
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var counter stats.Counter
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if statConn != nil {
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counter = statConn.WriteCounter
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}
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if c, ok := iConn.(*internet.PacketConnWrapper); ok {
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return &PacketWriter{
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PacketConnWrapper: c,
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Counter: counter,
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Handler: h,
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Context: ctx,
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UDPOverride: UDPOverride,
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}
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}
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return &buf.SequentialWriter{Writer: conn}
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}
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type PacketWriter struct {
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*internet.PacketConnWrapper
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stats.Counter
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*Handler
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context.Context
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UDPOverride net.Destination
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}
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func (w *PacketWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
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for {
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mb2, b := buf.SplitFirst(mb)
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mb = mb2
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if b == nil {
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break
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}
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var n int
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var err error
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if b.UDP != nil {
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if w.UDPOverride.Address != nil {
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b.UDP.Address = w.UDPOverride.Address
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}
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if w.UDPOverride.Port != 0 {
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b.UDP.Port = w.UDPOverride.Port
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}
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if w.Handler.config.hasStrategy() && b.UDP.Address.Family().IsDomain() {
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ip := w.Handler.resolveIP(w.Context, b.UDP.Address.Domain(), nil)
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if ip != nil {
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b.UDP.Address = ip
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}
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}
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destAddr, _ := net.ResolveUDPAddr("udp", b.UDP.NetAddr())
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if destAddr == nil {
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b.Release()
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continue
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}
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n, err = w.PacketConnWrapper.WriteTo(b.Bytes(), destAddr)
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} else {
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n, err = w.PacketConnWrapper.Write(b.Bytes())
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}
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b.Release()
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if err != nil {
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buf.ReleaseMulti(mb)
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return err
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}
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if w.Counter != nil {
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w.Counter.Add(int64(n))
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}
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}
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return nil
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}
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type FragmentWriter struct {
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fragment *Fragment
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writer io.Writer
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count uint64
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}
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func (f *FragmentWriter) Write(b []byte) (int, error) {
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f.count++
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if f.fragment.PacketsFrom == 0 && f.fragment.PacketsTo == 1 {
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if f.count != 1 || len(b) <= 5 || b[0] != 22 {
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return f.writer.Write(b)
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}
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recordLen := 5 + ((int(b[3]) << 8) | int(b[4]))
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if len(b) < recordLen { // maybe already fragmented somehow
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return f.writer.Write(b)
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}
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data := b[5:recordLen]
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buf := make([]byte, 1024)
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for from := 0; ; {
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to := from + int(randBetween(int64(f.fragment.LengthMin), int64(f.fragment.LengthMax)))
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if to > len(data) {
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to = len(data)
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}
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copy(buf[:3], b)
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copy(buf[5:], data[from:to])
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l := to - from
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from = to
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buf[3] = byte(l >> 8)
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buf[4] = byte(l)
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_, err := f.writer.Write(buf[:5+l])
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time.Sleep(time.Duration(randBetween(int64(f.fragment.IntervalMin), int64(f.fragment.IntervalMax))) * time.Millisecond)
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if err != nil {
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return 0, err
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}
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if from == len(data) {
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if len(b) > recordLen {
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n, err := f.writer.Write(b[recordLen:])
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if err != nil {
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return recordLen + n, err
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}
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}
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return len(b), nil
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}
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}
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}
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if f.fragment.PacketsFrom != 0 && (f.count < f.fragment.PacketsFrom || f.count > f.fragment.PacketsTo) {
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return f.writer.Write(b)
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}
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for from := 0; ; {
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to := from + int(randBetween(int64(f.fragment.LengthMin), int64(f.fragment.LengthMax)))
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if to > len(b) {
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to = len(b)
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}
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n, err := f.writer.Write(b[from:to])
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from += n
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time.Sleep(time.Duration(randBetween(int64(f.fragment.IntervalMin), int64(f.fragment.IntervalMax))) * time.Millisecond)
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if err != nil {
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return from, err
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}
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if from >= len(b) {
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return from, nil
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}
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}
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}
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// stolen from github.com/xtls/xray-core/transport/internet/reality
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func randBetween(left int64, right int64) int64 {
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if left == right {
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return left
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}
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bigInt, _ := rand.Int(rand.Reader, big.NewInt(right-left))
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return left + bigInt.Int64()
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}
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