/
forwarder.go
142 lines (118 loc) · 2.84 KB
/
forwarder.go
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package main
import (
"errors"
"fmt"
"io"
"net"
"os"
"time"
"github.com/hashicorp/yamux"
"golang.org/x/sync/errgroup"
)
func startForwardListener(logger *Logger, session *yamux.Session, local string, remote string) error {
logger.printf("listen forward: %v -> %v", local, remote)
listener, err := net.Listen("tcp4", local)
if err != nil {
return err
}
defer listener.Close()
for {
conn, err := listener.Accept()
if err != nil {
return err
}
go func() {
stream, err := session.OpenStream()
if err != nil {
conn.Close()
logger.errorln(err)
return
}
logger = logger.withStreamID(stream.StreamID())
logger.printf("connect accept: %v", conn.RemoteAddr())
defer func() {
logger.printf("connect close: %v", conn.RemoteAddr())
conn.Close()
}()
logger.printf("stream open: %06d", stream.StreamID())
defer func() {
logger.printf("stream close: %06d", stream.StreamID())
stream.Close()
}()
logger.printf("forward: %v -> %v", local, remote)
err = writeGob(stream, remote)
if err != nil {
logger.errorln(err)
return
}
err = handleForward(logger, conn, stream)
if err != nil {
logger.errorln(err)
return
}
}()
}
}
func startSessionAccepter(logger *Logger, session *yamux.Session) error {
for {
stream, err := session.AcceptStream()
if err != nil {
return fmt.Errorf("stream accept: %w", err)
}
go func() {
logger := logger.withStreamID(stream.StreamID())
logger.printf("stream accept: %06d", stream.StreamID())
defer func() {
logger.printf("stream close: %06d", stream.StreamID())
stream.Close()
}()
var remote string
err := readGob(stream, &remote)
if err != nil {
err = fmt.Errorf("recv desc: %w", err)
logger.errorln(err)
return
}
logger.printf("connect: stream -> %v", remote)
conn, err := net.Dial("tcp", remote)
if err != nil {
err = fmt.Errorf("connect error: %w", err)
logger.errorln(err)
return
}
logger.printf("connect open: %v", remote)
defer func() {
logger.printf("connect close: %v", remote)
conn.Close()
}()
err = handleForward(logger, conn, stream)
if err != nil {
logger.errorln(err)
}
}()
}
}
func handleForward(logger *Logger, conn net.Conn, stream *yamux.Stream) error {
g := new(errgroup.Group)
g.Go(func() error {
defer stream.SetDeadline(time.Now())
_, err := io.Copy(stream, conn)
if err != nil {
if !(errors.Is(err, io.EOF) || errors.Is(err, os.ErrDeadlineExceeded) || errors.Is(err, yamux.ErrTimeout)) {
return err
}
}
return nil
})
g.Go(func() error {
defer conn.SetDeadline(time.Now())
_, err := io.Copy(conn, stream)
if err != nil {
if !(errors.Is(err, io.EOF) || errors.Is(err, os.ErrDeadlineExceeded) || errors.Is(err, yamux.ErrTimeout)) {
return err
}
}
return nil
})
return g.Wait()
}