62 lines
1.7 KiB
Go
62 lines
1.7 KiB
Go
|
package proxy
|
||
|
|
|
||
|
|
import (
|
||
|
|
"io"
|
||
|
|
"net"
|
||
|
|
"sync/atomic"
|
||
|
|
)
|
||
|
|
|
||
|
|
// Conn represents a single proxied TCP connection.
|
||
|
|
type Conn struct {
|
||
|
|
src, dst net.Conn
|
||
|
|
stopping int32
|
||
|
|
}
|
||
|
|
|
||
|
|
// NewConn returns a conn joining the two given net.Conn
|
||
|
|
func NewConn(src, dst net.Conn) *Conn {
|
||
|
|
return &Conn{
|
||
|
|
src: src,
|
||
|
|
dst: dst,
|
||
|
|
stopping: 0,
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Close closes both connections.
|
||
|
|
func (c *Conn) Close() error {
|
||
|
|
// Note that net.Conn.Close can be called multiple times and atomic store is
|
||
|
|
// idempotent so no need to ensure we only do this once.
|
||
|
|
//
|
||
|
|
// Also note that we don't wait for CopyBytes to return here since we are
|
||
|
|
// closing the conns which is the only externally visible sideeffect of that
|
||
|
|
// goroutine running and there should be no way for it to hang or leak once
|
||
|
|
// the conns are closed so we can save the extra coordination.
|
||
|
|
atomic.StoreInt32(&c.stopping, 1)
|
||
|
|
c.src.Close()
|
||
|
|
c.dst.Close()
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// CopyBytes will continuously copy bytes in both directions between src and dst
|
||
|
|
// until either connection is closed.
|
||
|
|
func (c *Conn) CopyBytes() error {
|
||
|
|
defer c.Close()
|
||
|
|
|
||
|
|
go func() {
|
||
|
|
// Need this since Copy is only guaranteed to stop when it's source reader
|
||
|
|
// (second arg) hits EOF or error but either conn might close first possibly
|
||
|
|
// causing this goroutine to exit but not the outer one. See
|
||
|
|
// TestConnSrcClosing which will fail if you comment the defer below.
|
||
|
|
defer c.Close()
|
||
|
|
io.Copy(c.dst, c.src)
|
||
|
|
}()
|
||
|
|
|
||
|
|
_, err := io.Copy(c.src, c.dst)
|
||
|
|
// Note that we don't wait for the other goroutine to finish because it either
|
||
|
|
// already has due to it's src conn closing, or it will once our defer fires
|
||
|
|
// and closes the source conn. No need for the extra coordination.
|
||
|
|
if atomic.LoadInt32(&c.stopping) == 1 {
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
return err
|
||
|
|
}
|