yamuxhang.go

package main

import (
	"fmt"
	"net"
	"os"
	"time"

	"github.com/hashicorp/yamux"
)

func tcppipe() (net.Conn, net.Conn) {
	list, err := net.Listen("tcp", "0.0.0.0:0")
	if err != nil {
		panic(err)
	}

	con, err := net.Dial("tcp", list.Addr().String())
	if err != nil {
		panic(err)
	}

	con2, err := list.Accept()
	if err != nil {
		panic(err)
	}

	return con, con2
}

func main() {
	//a, b := net.Pipe()
	a, b := tcppipe() // the slight latency increase of tcp makes the bug more apparent

	cfg_a := &yamux.Config{
		AcceptBacklog:          16,
		ConnectionWriteTimeout: time.Second * 10,
		EnableKeepAlive:        true,
		MaxStreamWindowSize:    256 << 10,
		KeepAliveInterval:      time.Second * 10,
		LogOutput:              os.Stderr,
	}

	cfg_b := &yamux.Config{
		AcceptBacklog:          16,
		ConnectionWriteTimeout: time.Second * 10,
		EnableKeepAlive:        true,
		MaxStreamWindowSize:    256 << 10,
		KeepAliveInterval:      time.Second * 10,
		LogOutput:              os.Stderr,
	}

	s, err := yamux.Server(a, cfg_a)
	if err != nil {
		panic(err)
	}
	defer s.Close()

	c, err := yamux.Client(b, cfg_b)
	if err != nil {
		panic(err)
	}
	defer c.Close()

	go func() {
		for {
			ns, err := s.OpenStream()
			if err != nil {
				panic(err)
			}
			ns.Close()
			fmt.Println("opened - s")
		}
	}()

	go func() {
		for {
			ns, err := c.OpenStream()
			if err != nil {
				panic(err)
			}
			ns.Close()
			fmt.Println("opened - c")
		}
	}()

	acc1 := make(chan bool)
	go func() {
		for {
			select {
			case <-acc1:
			case <-time.After(time.Second):
				panic("we're hung captain! ( ONE )")
			}
		}
	}()

	acc2 := make(chan bool)
	go func() {
		for {
			select {
			case <-acc2:
			case <-time.After(time.Second):
				panic("we're hung captain! ( TWO )")
			}
		}
	}()

	go func() {
		for {
			ac, err := c.AcceptStream()
			if err != nil {
				panic(err)
			}
			ac.Close()
			fmt.Println("accepted - c")
			acc1 <- true
		}
	}()

	for {
		ac, err := s.AcceptStream()
		if err != nil {
			panic(err)
		}
		ac.Close()
		fmt.Println("accepted - s")
		acc2 <- true
	}

	time.Sleep(time.Second * 5)
}