// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package net

import (
	"fmt"
	"net/internal/socktest"
	"runtime"
	"sync"
	"testing"
	"time"
)

func TestSelfConnect(t *testing.T) {
	if runtime.GOOS == "windows" {
		// TODO(brainman): do not know why it hangs.
		t.Skip("skipping known-broken test on windows")
	}

	// Test that Dial does not honor self-connects.
	// See the comment in DialTCP.

	// Find a port that would be used as a local address.
	l, err := Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatal(err)
	}
	c, err := Dial("tcp", l.Addr().String())
	if err != nil {
		t.Fatal(err)
	}
	addr := c.LocalAddr().String()
	c.Close()
	l.Close()

	// Try to connect to that address repeatedly.
	n := 100000
	if testing.Short() {
		n = 1000
	}
	switch runtime.GOOS {
	case "darwin", "dragonfly", "freebsd", "netbsd", "openbsd", "plan9", "solaris", "windows":
		// Non-Linux systems take a long time to figure
		// out that there is nothing listening on localhost.
		n = 100
	}
	for i := 0; i < n; i++ {
		c, err := DialTimeout("tcp", addr, time.Millisecond)
		if err == nil {
			if c.LocalAddr().String() == addr {
				t.Errorf("#%d: Dial %q self-connect", i, addr)
			} else {
				t.Logf("#%d: Dial %q succeeded - possibly racing with other listener", i, addr)
			}
			c.Close()
		}
	}
}

func TestDialTimeoutFDLeak(t *testing.T) {
	switch runtime.GOOS {
	case "plan9":
		t.Skipf("%s does not have full support of socktest", runtime.GOOS)
	}

	const T = 100 * time.Millisecond

	switch runtime.GOOS {
	case "plan9", "windows":
		origTestHookDialChannel := testHookDialChannel
		testHookDialChannel = func() { time.Sleep(2 * T) }
		defer func() { testHookDialChannel = origTestHookDialChannel }()
		if runtime.GOOS == "plan9" {
			break
		}
		fallthrough
	default:
		sw.Set(socktest.FilterConnect, func(so *socktest.Status) (socktest.AfterFilter, error) {
			time.Sleep(2 * T)
			return nil, errTimeout
		})
		defer sw.Set(socktest.FilterConnect, nil)
	}

	before := sw.Sockets()
	const N = 100
	var wg sync.WaitGroup
	wg.Add(N)
	for i := 0; i < N; i++ {
		go func() {
			defer wg.Done()
			// This dial never starts to send any SYN
			// segment because of above socket filter and
			// test hook.
			c, err := DialTimeout("tcp", "127.0.0.1:0", T)
			if err == nil {
				t.Errorf("unexpectedly established: tcp:%s->%s", c.LocalAddr(), c.RemoteAddr())
				c.Close()
			}
		}()
	}
	wg.Wait()
	after := sw.Sockets()
	if len(after) != len(before) {
		t.Errorf("got %d; want %d", len(after), len(before))
	}
}

func TestDialerDualStackFDLeak(t *testing.T) {
	switch runtime.GOOS {
	case "plan9":
		t.Skipf("%s does not have full support of socktest", runtime.GOOS)
	case "windows":
		t.Skipf("not implemented a way to cancel dial racers in TCP SYN-SENT state on %s", runtime.GOOS)
	}
	if !supportsIPv4 || !supportsIPv6 {
		t.Skip("ipv4 or ipv6 is not supported")
	}

	origTestHookLookupIP := testHookLookupIP
	defer func() { testHookLookupIP = origTestHookLookupIP }()
	testHookLookupIP = lookupLocalhost
	handler := func(dss *dualStackServer, ln Listener) {
		for {
			c, err := ln.Accept()
			if err != nil {
				return
			}
			c.Close()
		}
	}
	dss, err := newDualStackServer([]streamListener{
		{network: "tcp4", address: "127.0.0.1"},
		{network: "tcp6", address: "::1"},
	})
	if err != nil {
		t.Fatal(err)
	}
	defer dss.teardown()
	if err := dss.buildup(handler); err != nil {
		t.Fatal(err)
	}

	before := sw.Sockets()
	const T = 100 * time.Millisecond
	const N = 10
	var wg sync.WaitGroup
	wg.Add(N)
	d := &Dialer{DualStack: true, Timeout: T}
	for i := 0; i < N; i++ {
		go func() {
			defer wg.Done()
			c, err := d.Dial("tcp", JoinHostPort("localhost", dss.port))
			if err != nil {
				t.Error(err)
				return
			}
			c.Close()
		}()
	}
	wg.Wait()
	time.Sleep(2 * T) // wait for the dial racers to stop
	after := sw.Sockets()
	if len(after) != len(before) {
		t.Errorf("got %d; want %d", len(after), len(before))
	}
}

func TestDialerLocalAddr(t *testing.T) {
	ch := make(chan error, 1)
	handler := func(ls *localServer, ln Listener) {
		c, err := ln.Accept()
		if err != nil {
			ch <- fmt.Errorf("Accept failed: %v", err)
			return
		}
		defer c.Close()
		ch <- nil
	}
	ls, err := newLocalServer("tcp")
	if err != nil {
		t.Fatal(err)
	}
	defer ls.teardown()
	if err := ls.buildup(handler); err != nil {
		t.Fatal(err)
	}

	laddr, err := ResolveTCPAddr(ls.Listener.Addr().Network(), ls.Listener.Addr().String())
	if err != nil {
		t.Fatalf("ResolveTCPAddr failed: %v", err)
	}
	laddr.Port = 0
	d := &Dialer{LocalAddr: laddr}
	c, err := d.Dial(ls.Listener.Addr().Network(), ls.Addr().String())
	if err != nil {
		t.Fatalf("Dial failed: %v", err)
	}
	defer c.Close()
	c.Read(make([]byte, 1))
	err = <-ch
	if err != nil {
		t.Error(err)
	}
}

func TestDialerDualStack(t *testing.T) {
	if !supportsIPv4 || !supportsIPv6 {
		t.Skip("ipv4 or ipv6 is not supported")
	}

	origTestHookLookupIP := testHookLookupIP
	defer func() { testHookLookupIP = origTestHookLookupIP }()
	testHookLookupIP = lookupLocalhost
	handler := func(dss *dualStackServer, ln Listener) {
		for {
			c, err := ln.Accept()
			if err != nil {
				return
			}
			c.Close()
		}
	}
	dss, err := newDualStackServer([]streamListener{
		{network: "tcp4", address: "127.0.0.1"},
		{network: "tcp6", address: "::1"},
	})
	if err != nil {
		t.Fatal(err)
	}
	defer dss.teardown()
	if err := dss.buildup(handler); err != nil {
		t.Fatal(err)
	}

	const T = 100 * time.Millisecond
	d := &Dialer{DualStack: true, Timeout: T}
	for range dss.lns {
		c, err := d.Dial("tcp", JoinHostPort("localhost", dss.port))
		if err != nil {
			t.Error(err)
			continue
		}
		switch addr := c.LocalAddr().(*TCPAddr); {
		case addr.IP.To4() != nil:
			dss.teardownNetwork("tcp4")
		case addr.IP.To16() != nil && addr.IP.To4() == nil:
			dss.teardownNetwork("tcp6")
		}
		c.Close()
	}
	time.Sleep(2 * T) // wait for the dial racers to stop
}

func TestDialerKeepAlive(t *testing.T) {
	handler := func(ls *localServer, ln Listener) {
		for {
			c, err := ln.Accept()
			if err != nil {
				return
			}
			c.Close()
		}
	}
	ls, err := newLocalServer("tcp")
	if err != nil {
		t.Fatal(err)
	}
	defer ls.teardown()
	if err := ls.buildup(handler); err != nil {
		t.Fatal(err)
	}
	defer func() {
		testHookSetKeepAlive = func() {}
	}()

	for _, keepAlive := range []bool{false, true} {
		got := false
		testHookSetKeepAlive = func() { got = true }
		var d Dialer
		if keepAlive {
			d.KeepAlive = 30 * time.Second
		}
		c, err := d.Dial("tcp", ls.Listener.Addr().String())
		if err != nil {
			t.Fatal(err)
		}
		c.Close()
		if got != keepAlive {
			t.Errorf("Dialer.KeepAlive = %v: SetKeepAlive called = %v, want %v", d.KeepAlive, got, !got)
		}
	}
}