Migrate some of the nat tests in integration-cli to api tests

This fix migrates nat tests in docker_cli_nat_test.go
to api tests.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

integration/container/nat_test.go

@@ -0,0 +1,147 @@
+package container
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/container"
+	"github.com/docker/docker/api/types/network"
+	"github.com/docker/docker/integration/util/request"
+	"github.com/docker/go-connections/nat"
+	"github.com/gotestyourself/gotestyourself/poll"
+	"github.com/gotestyourself/gotestyourself/skip"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNetworkNat(t *testing.T) {
+	skip.If(t, !testEnv.IsLocalDaemon())
+
+	defer setupTest(t)()
+
+	msg := "it works"
+	startServerContainer(t, msg, 8080)
+
+	endpoint := getExternalAddress(t)
+	conn, err := net.Dial("tcp", fmt.Sprintf("%s:%d", endpoint.String(), 8080))
+	require.NoError(t, err)
+	defer conn.Close()
+
+	data, err := ioutil.ReadAll(conn)
+	require.NoError(t, err)
+	assert.Equal(t, strings.TrimSpace(string(data)), msg)
+}
+
+func TestNetworkLocalhostTCPNat(t *testing.T) {
+	skip.If(t, !testEnv.IsLocalDaemon())
+
+	defer setupTest(t)()
+
+	msg := "hi yall"
+	startServerContainer(t, msg, 8081)
+
+	conn, err := net.Dial("tcp", "localhost:8081")
+	require.NoError(t, err)
+	defer conn.Close()
+
+	data, err := ioutil.ReadAll(conn)
+	require.NoError(t, err)
+	assert.Equal(t, strings.TrimSpace(string(data)), msg)
+}
+
+func TestNetworkLoopbackNat(t *testing.T) {
+	skip.If(t, !testEnv.IsLocalDaemon())
+
+	msg := "it works"
+	startServerContainer(t, msg, 8080)
+
+	endpoint := getExternalAddress(t)
+
+	client := request.NewAPIClient(t)
+	ctx := context.Background()
+	c, err := client.ContainerCreate(ctx,
+		&container.Config{
+			Image: "busybox",
+			Cmd:   []string{"sh", "-c", fmt.Sprintf("stty raw && nc -w 5 %s 8080", endpoint.String())},
+			Tty:   true,
+		},
+		&container.HostConfig{
+			NetworkMode: "container:server",
+		},
+		nil,
+		"")
+	require.NoError(t, err)
+
+	err = client.ContainerStart(ctx, c.ID, types.ContainerStartOptions{})
+	require.NoError(t, err)
+
+	poll.WaitOn(t, containerIsStopped(ctx, client, c.ID), poll.WithDelay(100*time.Millisecond))
+
+	body, err := client.ContainerLogs(ctx, c.ID, types.ContainerLogsOptions{
+		ShowStdout: true,
+	})
+	require.NoError(t, err)
+	defer body.Close()
+
+	var b bytes.Buffer
+	_, err = io.Copy(&b, body)
+	require.NoError(t, err)
+
+	assert.Equal(t, strings.TrimSpace(b.String()), msg)
+}
+
+func startServerContainer(t *testing.T, msg string, port int) string {
+	client := request.NewAPIClient(t)
+	ctx := context.Background()
+
+	c, err := client.ContainerCreate(ctx,
+		&container.Config{
+			Image: "busybox",
+			Cmd:   []string{"sh", "-c", fmt.Sprintf("echo %q | nc -lp %d", msg, port)},
+			ExposedPorts: map[nat.Port]struct{}{
+				nat.Port(fmt.Sprintf("%d/tcp", port)): {},
+			},
+		},
+		&container.HostConfig{
+			PortBindings: nat.PortMap{
+				nat.Port(fmt.Sprintf("%d/tcp", port)): []nat.PortBinding{
+					{
+						HostPort: fmt.Sprintf("%d", port),
+					},
+				},
+			},
+		},
+		&network.NetworkingConfig{},
+		"server",
+	)
+	require.NoError(t, err)
+
+	err = client.ContainerStart(ctx, c.ID, types.ContainerStartOptions{})
+	require.NoError(t, err)
+
+	poll.WaitOn(t, containerIsInState(ctx, client, c.ID, "running"), poll.WithDelay(100*time.Millisecond))
+
+	return c.ID
+}
+
+func getExternalAddress(t *testing.T) net.IP {
+	iface, err := net.InterfaceByName("eth0")
+	skip.If(t, err != nil, "Test not running with `make test-integration`. Interface eth0 not found: %s", err)
+
+	ifaceAddrs, err := iface.Addrs()
+	require.NoError(t, err)
+	assert.NotEqual(t, len(ifaceAddrs), 0)
+
+	ifaceIP, _, err := net.ParseCIDR(ifaceAddrs[0].String())
+	require.NoError(t, err)
+
+	return ifaceIP
+}