TCPConn.Close() does not close the port leaving it in TIME_WAIT status #32961
Description
What version of Go are you using (go version)?
$ go version go version go1.12.6 linux/amd64
Does this issue reproduce with the latest release?
Yes
What operating system and processor architecture are you using (go env)?
$ go env GOARCH="amd64" GOBIN="" GOCACHE="/home/daniele/.cache/go-build" GOEXE="" GOFLAGS="" GOHOSTARCH="amd64" GOHOSTOS="linux" GOOS="linux" GOPATH="/home/daniele/go" GOPROXY="" GORACE="" GOROOT="/usr/local/go" GOTMPDIR="" GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64" GCCGO="gccgo" CC="gcc" CXX="g++" CGO_ENABLED="1" GOMOD="" CGO_CFLAGS="-g -O2" CGO_CPPFLAGS="" CGO_CXXFLAGS="-g -O2" CGO_FFLAGS="-g -O2" CGO_LDFLAGS="-g -O2" PKG_CONFIG="pkg-config" GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build361582700=/tmp/go-build -gno-record-gcc-switches"
What did you do?
I had this file: main.go:
package main
import (
"errors"
"flag"
"fmt"
"io/ioutil"
"log"
"net"
"os"
"time"
)
func main() {
mode := flag.String("mode", "", "[client|server]")
flag.Parse()
if *mode == "server" {
go runServer()
for {
time.Sleep(2 * time.Second)
}
} else if *mode == "client" {
runClient()
} else {
log.Fatal(errors.New("wrong command line parameter"))
os.Exit(1)
}
}
func runServer() {
listener, err := net.Listen("tcp", ":12000")
if err != nil {
log.Fatal(err)
}
for {
conn, err := listener.Accept()
if err != nil {
log.Fatal(err)
}
go handleConnection(conn)
}
}
func runClient() {
LocalAddr, err := net.ResolveTCPAddr("tcp", "127.0.0.1:12001")
RemoteEP := net.TCPAddr{IP: net.ParseIP("127.0.0.1"), Port: 12000}
conn, err := net.DialTCP("tcp", LocalAddr, &RemoteEP)
if err != nil {
log.Fatal(err)
}
fmt.Fprintf(conn, "hi, I'm a client\n")
conn.CloseWrite()
b, err := ioutil.ReadAll(conn)
if err != nil {
log.Fatal(err)
}
fmt.Println(string(b))
conn.Close()
}
func handleConnection(connection net.Conn) {
b, err := ioutil.ReadAll(connection)
if err != nil {
log.Fatal(err)
}
fmt.Println("received: ", string(b))
fmt.Fprintf(connection, "hi, welcome!\n")
connection.Close()
}
i run those three commands
$go run main.go -mode server $go run main.go -mode client $netstat -an | grep 12000
What did you expect to see?
i expect the output of the netstat command to be:
tcp6 0 0 :::12000 :::* LISTEN
What did you see instead?
tcp 0 0 127.0.0.1:12001 127.0.0.1:12000 TIME_WAIT tcp6 0 0 :::12000 :::* LISTEN