torrent/reuse_test.go

80 lines
2.4 KiB
Go

package torrent
import (
"context"
"net"
"sync/atomic"
"syscall"
"testing"
"github.com/anacrolix/log"
qt "github.com/frankban/quicktest"
)
// Show that multiple connections from the same local TCP port to the same remote port will fail.
func TestTcpPortReuseIsABadIdea(t *testing.T) {
remote, err := net.Listen("tcp", "localhost:0")
c := qt.New(t)
c.Assert(err, qt.IsNil)
defer remote.Close()
dialer := net.Dialer{}
// Show that we can't duplicate an existing connection even with various socket options.
dialer.Control = func(network, address string, c syscall.RawConn) (err error) {
return c.Control(func(fd uintptr) {
err = setReusePortSockOpts(fd)
})
}
// Tie up a local port to the remote.
first, err := dialer.Dial("tcp", remote.Addr().String())
c.Assert(err, qt.IsNil)
defer first.Close()
// Show that dialling the remote with the same local port fails.
dialer.LocalAddr = first.LocalAddr()
_, err = dialer.Dial("tcp", remote.Addr().String())
c.Assert(err, qt.IsNotNil)
// Show that not fixing the local port again allows connections to succeed.
dialer.LocalAddr = nil
second, err := dialer.Dial("tcp", remote.Addr().String())
c.Assert(err, qt.IsNil)
second.Close()
}
// Show that multiple connections from the same local utp socket to the same remote port will
// succeed. This is necessary for ut_holepunch to work.
func TestUtpLocalPortIsReusable(t *testing.T) {
const network = "udp"
c := qt.New(t)
remote, err := NewUtpSocket(network, "localhost:0", nil, log.Default)
c.Assert(err, qt.IsNil)
defer remote.Close()
var remoteAccepts int32
doneAccepting := make(chan struct{})
go func() {
defer close(doneAccepting)
for {
c, err := remote.Accept()
if err != nil {
if atomic.LoadInt32(&remoteAccepts) != 2 {
t.Logf("error accepting on remote: %v", err)
}
break
}
// This is not a leak, bugger off.
defer c.Close()
atomic.AddInt32(&remoteAccepts, 1)
}
}()
local, err := NewUtpSocket(network, "localhost:0", nil, log.Default)
c.Assert(err, qt.IsNil)
defer local.Close()
first, err := local.DialContext(context.Background(), network, remote.Addr().String())
c.Assert(err, qt.IsNil)
defer first.Close()
second, err := local.DialContext(context.Background(), network, remote.Addr().String())
c.Assert(err, qt.IsNil)
defer second.Close()
remote.Close()
<-doneAccepting
c.Assert(atomic.LoadInt32(&remoteAccepts), qt.Equals, int32(2))
}