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forward.go
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forward.go
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package caddy
import (
"context"
"io"
"math"
"net"
bytesext "github.com/damnever/libext-go/bytes"
errorsext "github.com/damnever/libext-go/errors"
ioext "github.com/damnever/libext-go/io"
netext "github.com/damnever/libext-go/net"
"go.uber.org/zap"
"github.com/damnever/goodog/internal/pkg/encoding"
goodogioutil "github.com/damnever/goodog/internal/pkg/ioutil"
)
type forwarder struct {
opts Options
dialer *net.Dialer
logger *zap.Logger
udpBufferPool *bytesext.Pool
}
func newForwarder(logger *zap.Logger, opts Options) *forwarder {
return &forwarder{
opts: opts,
dialer: &net.Dialer{Timeout: opts.ConnectTimeout},
logger: logger,
udpBufferPool: bytesext.NewPoolWith(0, math.MaxUint16),
}
}
func (f *forwarder) ForwardTCP(ctx context.Context, downstream io.ReadWriteCloser) error {
upstreamConn, err := f.dialer.DialContext(ctx, "tcp", f.opts.UpstreamTCP)
if err != nil {
upstreamConn.Close()
return err
}
upstream := netext.NewTimedConn(upstreamConn, f.opts.Timeout, f.opts.Timeout)
errc := make(chan error, 2)
go f.stream(downstream, upstream, errc)
go f.stream(upstream, downstream, errc)
return f.wait(ctx, upstreamConn.Close, downstream.Close, errc, 2)
}
func (f *forwarder) ForwardUDP(ctx context.Context, downstream io.ReadWriteCloser) error {
upstreamConn, err := f.dialer.DialContext(ctx, "udp", f.opts.UpstreamUDP)
if err != nil {
downstream.Close()
return err
}
upstream := netext.NewTimedConn(upstreamConn, f.opts.Timeout, f.opts.Timeout)
errc := make(chan error, 2)
go func() { // upstream -> downstream
buf := f.udpBufferPool.Get(math.MaxUint16)
var (
n int
err error
)
for {
if n, err = upstream.Read(buf); err != nil {
break
}
if err = encoding.WriteU16SizedBytes(downstream, buf[:n]); err == nil {
if f, ok := downstream.(ioext.Flusher); ok {
err = f.Flush()
}
}
if err != nil {
break
}
}
f.udpBufferPool.Put(buf)
errc <- err
}()
go func() { // downstream -> upstream
buf := f.udpBufferPool.Get(math.MaxUint16)
var (
n int
err error
)
for {
if n, err = encoding.ReadU16SizedBytes(downstream, buf); err != nil {
break
}
// NOTE: use of WriteTo with pre-connected connection
if _, err = upstream.Write(buf[:n]); err != nil {
break
}
}
f.udpBufferPool.Put(buf)
errc <- err
}()
return f.wait(ctx, upstreamConn.Close, downstream.Close, errc, 2)
}
func (f *forwarder) wait(ctx context.Context, upCloseFunc, downCloseFunc func() error, errc <-chan error, n int) error {
donec := ctx.Done()
multierr := &errorsext.MultiErr{}
closed := false
for n > 0 {
select {
case err := <-errc:
n--
multierr.Append(err)
case <-donec:
donec = nil
}
if !closed {
closed = true
_ = upCloseFunc()
_ = downCloseFunc()
}
}
if !closed {
_ = upCloseFunc()
_ = downCloseFunc()
}
return multierr.Err()
}
func (f *forwarder) stream(dst io.Writer, src io.Reader, errc chan error) {
_, err := goodogioutil.Copy(dst, src, false)
errc <- err
}