tstest/integration/vms: split up test framework into files (#2396)

My spatial memory functions poorly with large files and the vms_test.go
file recently surpassed the point where it functions adequately. This
patch splits up vms_test.go into more files to make my spatial memory
function like I need it to.

Signed-off-by: Christine Dodrill <xe@tailscale.com>

tstest/integration/vms/vms_steps_test.go

@@ -0,0 +1,134 @@
+// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build linux
+
+package vms
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"net"
+	"net/http"
+	"strings"
+	"testing"
+	"time"
+
+	"golang.org/x/crypto/ssh"
+	"inet.af/netaddr"
+)
+
+const timeout = 15 * time.Second
+
+func retry(t *testing.T, fn func() error) {
+	t.Helper()
+	const tries = 3
+	var err error
+	for i := 0; i < tries; i++ {
+		err = fn()
+		if err != nil {
+			t.Logf("%dth invocation failed, trying again: %v", i, err)
+			time.Sleep(50 * time.Millisecond)
+		}
+		if err == nil {
+			return
+		}
+	}
+	t.Fatalf("tried %d times, got: %v", tries, err)
+}
+
+func (h Harness) testPing(t *testing.T, ipAddr netaddr.IP, cli *ssh.Client) {
+	var outp []byte
+	var err error
+	retry(t, func() error {
+		sess := getSession(t, cli)
+
+		outp, err = sess.CombinedOutput(fmt.Sprintf("tailscale ping -c 1 %s", ipAddr))
+		return err
+	})
+
+	if !bytes.Contains(outp, []byte("pong")) {
+		t.Log(string(outp))
+		t.Fatal("no pong")
+	}
+
+	retry(t, func() error {
+		sess := getSession(t, cli)
+
+		// NOTE(Xe): the ping command is inconsistent across distros. Joy.
+		pingCmd := fmt.Sprintf("sh -c 'ping -c 1 %[1]s || ping -6 -c 1 %[1]s || ping6 -c 1 %[1]s\n'", ipAddr)
+		t.Logf("running %q", pingCmd)
+		outp, err = sess.CombinedOutput(pingCmd)
+		return err
+	})
+
+	if !bytes.Contains(outp, []byte("bytes")) {
+		t.Log(string(outp))
+		t.Fatalf("wanted output to contain %q, it did not", "bytes")
+	}
+}
+
+func getSession(t *testing.T, cli *ssh.Client) *ssh.Session {
+	sess, err := cli.NewSession()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Cleanup(func() {
+		sess.Close()
+	})
+
+	return sess
+}
+
+func (h Harness) testOutgoingTCP(t *testing.T, ipAddr netaddr.IP, cli *ssh.Client) {
+	const sendmsg = "this is a message that curl won't print"
+	ctx, cancel := context.WithCancel(context.Background())
+	s := &http.Server{
+		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			t.Logf("http connection from %s", r.RemoteAddr)
+			cancel()
+			fmt.Fprintln(w, sendmsg)
+		}),
+	}
+	ln, err := net.Listen("tcp", net.JoinHostPort("::", "0"))
+	if err != nil {
+		t.Fatalf("can't make HTTP server: %v", err)
+	}
+	_, port, _ := net.SplitHostPort(ln.Addr().String())
+	go s.Serve(ln)
+
+	// sess := getSession(t, cli)
+	// sess.Stderr = logger.FuncWriter(t.Logf)
+	// sess.Stdout = logger.FuncWriter(t.Logf)
+	// sess.Run("ip route show table all")
+
+	// sess = getSession(t, cli)
+	// sess.Stderr = logger.FuncWriter(t.Logf)
+	// sess.Stdout = logger.FuncWriter(t.Logf)
+	// sess.Run("sysctl -a")
+
+	var outp []byte
+	retry(t, func() error {
+		var err error
+		sess := getSession(t, cli)
+		v6Arg := ""
+		if ipAddr.Is6() {
+			v6Arg = "-6 -g"
+		}
+		cmd := fmt.Sprintf("curl -v %s -s -f http://%s\n", v6Arg, net.JoinHostPort(ipAddr.String(), port))
+		t.Logf("running: %s", cmd)
+		outp, err = sess.CombinedOutput(cmd)
+		if err != nil {
+			t.Log(string(outp))
+		}
+		return err
+	})
+
+	if msg := string(bytes.TrimSpace(outp)); !strings.Contains(msg, sendmsg) {
+		t.Fatalf("wanted %q, got: %q", sendmsg, msg)
+	}
+	<-ctx.Done()
+}