Source file src/pkg/net/dialgoogle_test.go

// Copyright 2009 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 (
    "flag"
    "io"
    "syscall"
    "testing"
)

// If an IPv6 tunnel is running (see go/stubl), we can try dialing a real IPv6 address.
var ipv6 = flag.Bool("ipv6", false, "assume ipv6 tunnel is present")

// fd is already connected to the destination, port 80.
// Run an HTTP request to fetch the appropriate page.
func fetchGoogle(t *testing.T, fd Conn, network, addr string) {
    req := []byte("GET /intl/en/privacy.html HTTP/1.0\r\nHost: www.google.com\r\n\r\n")
    n, err := fd.Write(req)

    buf := make([]byte, 1000)
    n, err = io.ReadFull(fd, buf)

    if n < 1000 {
        t.Errorf("fetchGoogle: short HTTP read from %s %s - %v", network, addr, err)
        return
    }
}

func doDial(t *testing.T, network, addr string) {
    fd, err := Dial(network, "", addr)
    if err != nil {
        t.Errorf("Dial(%q, %q, %q) = _, %v", network, "", addr, err)
        return
    }
    fetchGoogle(t, fd, network, addr)
    fd.Close()
}

var googleaddrs = []string{
    "74.125.19.99:80",
    "www.google.com:80",
    "74.125.19.99:http",
    "www.google.com:http",
    "074.125.019.099:0080",
    "[::ffff:74.125.19.99]:80",
    "[::ffff:4a7d:1363]:80",
    "[0:0:0:0:0000:ffff:74.125.19.99]:80",
    "[0:0:0:0:000000:ffff:74.125.19.99]:80",
    "[0:0:0:0:0:ffff::74.125.19.99]:80",
    "[2001:4860:0:2001::68]:80", // ipv6.google.com; removed if ipv6 flag not set
}

func TestDialGoogle(t *testing.T) {
    // If no ipv6 tunnel, don't try the last address.
    if !*ipv6 {
        googleaddrs[len(googleaddrs)-1] = ""
    }

    for i := 0; i < len(googleaddrs); i++ {
        addr := googleaddrs[i]
        if addr == "" {
            continue
        }
        t.Logf("-- %s --", addr)
        doDial(t, "tcp", addr)
        if addr[0] != '[' {
            doDial(t, "tcp4", addr)

            if !preferIPv4 {
                // make sure preferIPv4 flag works.
                preferIPv4 = true
                syscall.SocketDisableIPv6 = true
                doDial(t, "tcp4", addr)
                syscall.SocketDisableIPv6 = false
                preferIPv4 = false
            }
        }

        // Only run tcp6 if the kernel will take it.
        if kernelSupportsIPv6() {
            doDial(t, "tcp6", addr)
        }
    }
}