forked from uber/tchannel-go
/
tcp_raw_relay.go
100 lines (84 loc) · 2.56 KB
/
tcp_raw_relay.go
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// Copyright (c) 2015 Uber Technologies, Inc.
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package benchmark
import (
"io"
"log"
"net"
"go.uber.org/atomic"
)
type tcpRelay struct {
destI atomic.Int32
dests []string
ln net.Listener
handleConn func(fromClient bool, src, dst net.Conn)
}
func newTCPRelay(dests []string, handleConn func(fromClient bool, src, dst net.Conn)) (*tcpRelay, error) {
ln, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
return nil, err
}
relay := &tcpRelay{
dests: dests,
ln: ln,
handleConn: handleConn,
}
go relay.acceptLoop()
return relay, nil
}
// NewTCPRawRelay creates a relay that just pipes data from one connection
// to another directly.
func NewTCPRawRelay(dests []string) (Relay, error) {
return newTCPRelay(dests, func(_ bool, src, dst net.Conn) {
io.Copy(src, dst)
})
}
func (r *tcpRelay) acceptLoop() {
for {
conn, err := r.ln.Accept()
if err, ok := err.(net.Error); ok && err.Temporary() {
continue
}
if err != nil {
return
}
go r.handleIncoming(conn)
}
}
func (r *tcpRelay) handleIncoming(src net.Conn) {
defer src.Close()
dst, err := net.Dial("tcp", r.nextDestination())
if err != nil {
log.Printf("Connection failed: %v", err)
return
}
defer dst.Close()
go r.handleConn(true, src, dst)
r.handleConn(false, dst, src)
}
func (r *tcpRelay) nextDestination() string {
i := int(r.destI.Inc()-1) % len(r.dests)
return r.dests[i]
}
func (r *tcpRelay) HostPort() string {
return r.ln.Addr().String()
}
func (r *tcpRelay) Close() {
r.ln.Close()
}