Add TCP Middlewares support

pkg/middlewares/tcp/ipwhitelist/ip_whitelist.go

@@ -0,0 +1,65 @@
+package tcpipwhitelist
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/traefik/traefik/v2/pkg/config/dynamic"
+	"github.com/traefik/traefik/v2/pkg/ip"
+	"github.com/traefik/traefik/v2/pkg/log"
+	"github.com/traefik/traefik/v2/pkg/middlewares"
+	"github.com/traefik/traefik/v2/pkg/tcp"
+)
+
+const (
+	typeName = "IPWhiteListerTCP"
+)
+
+// ipWhiteLister is a middleware that provides Checks of the Requesting IP against a set of Whitelists.
+type ipWhiteLister struct {
+	next        tcp.Handler
+	whiteLister *ip.Checker
+	name        string
+}
+
+// New builds a new TCP IPWhiteLister given a list of CIDR-Strings to whitelist.
+func New(ctx context.Context, next tcp.Handler, config dynamic.TCPIPWhiteList, name string) (tcp.Handler, error) {
+	logger := log.FromContext(middlewares.GetLoggerCtx(ctx, name, typeName))
+	logger.Debug("Creating middleware")
+
+	if len(config.SourceRange) == 0 {
+		return nil, errors.New("sourceRange is empty, IPWhiteLister not created")
+	}
+
+	checker, err := ip.NewChecker(config.SourceRange)
+	if err != nil {
+		return nil, fmt.Errorf("cannot parse CIDR whitelist %s: %w", config.SourceRange, err)
+	}
+
+	logger.Debugf("Setting up IPWhiteLister with sourceRange: %s", config.SourceRange)
+
+	return &ipWhiteLister{
+		whiteLister: checker,
+		next:        next,
+		name:        name,
+	}, nil
+}
+
+func (wl *ipWhiteLister) ServeTCP(conn tcp.WriteCloser) {
+	ctx := middlewares.GetLoggerCtx(context.Background(), wl.name, typeName)
+	logger := log.FromContext(ctx)
+
+	addr := conn.RemoteAddr().String()
+
+	err := wl.whiteLister.IsAuthorized(addr)
+	if err != nil {
+		logger.Errorf("Connection from %s rejected: %v", addr, err)
+		conn.Close()
+		return
+	}
+
+	logger.Debugf("Connection from %s accepted", addr)
+
+	wl.next.ServeTCP(conn)
+}

pkg/middlewares/tcp/ipwhitelist/ip_whitelist_test.go

@@ -0,0 +1,139 @@
+package tcpipwhitelist
+
+import (
+	"context"
+	"io/ioutil"
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/traefik/traefik/v2/pkg/config/dynamic"
+	"github.com/traefik/traefik/v2/pkg/tcp"
+)
+
+func TestNewIPWhiteLister(t *testing.T) {
+	testCases := []struct {
+		desc          string
+		whiteList     dynamic.TCPIPWhiteList
+		expectedError bool
+	}{
+		{
+			desc:          "Empty config",
+			whiteList:     dynamic.TCPIPWhiteList{},
+			expectedError: true,
+		},
+		{
+			desc: "invalid IP",
+			whiteList: dynamic.TCPIPWhiteList{
+				SourceRange: []string{"foo"},
+			},
+			expectedError: true,
+		},
+		{
+			desc: "valid IP",
+			whiteList: dynamic.TCPIPWhiteList{
+				SourceRange: []string{"10.10.10.10"},
+			},
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			next := tcp.HandlerFunc(func(conn tcp.WriteCloser) {})
+			whiteLister, err := New(context.Background(), next, test.whiteList, "traefikTest")
+
+			if test.expectedError {
+				assert.Error(t, err)
+			} else {
+				require.NoError(t, err)
+				assert.NotNil(t, whiteLister)
+			}
+		})
+	}
+}
+
+func TestIPWhiteLister_ServeHTTP(t *testing.T) {
+	testCases := []struct {
+		desc       string
+		whiteList  dynamic.TCPIPWhiteList
+		remoteAddr string
+		expected   string
+	}{
+		{
+			desc: "authorized with remote address",
+			whiteList: dynamic.TCPIPWhiteList{
+				SourceRange: []string{"20.20.20.20"},
+			},
+			remoteAddr: "20.20.20.20:1234",
+			expected:   "OK",
+		},
+		{
+			desc: "non authorized with remote address",
+			whiteList: dynamic.TCPIPWhiteList{
+				SourceRange: []string{"20.20.20.20"},
+			},
+			remoteAddr: "20.20.20.21:1234",
+		},
+	}
+
+	for _, test := range testCases {
+		test := test
+		t.Run(test.desc, func(t *testing.T) {
+			t.Parallel()
+
+			next := tcp.HandlerFunc(func(conn tcp.WriteCloser) {
+				write, err := conn.Write([]byte("OK"))
+				require.NoError(t, err)
+				assert.Equal(t, 2, write)
+
+				err = conn.Close()
+				require.NoError(t, err)
+			})
+
+			whiteLister, err := New(context.Background(), next, test.whiteList, "traefikTest")
+			require.NoError(t, err)
+
+			server, client := net.Pipe()
+
+			go func() {
+				whiteLister.ServeTCP(&contextWriteCloser{client, addr{test.remoteAddr}})
+			}()
+
+			read, err := ioutil.ReadAll(server)
+			require.NoError(t, err)
+
+			assert.Equal(t, test.expected, string(read))
+		})
+	}
+}
+
+type contextWriteCloser struct {
+	net.Conn
+	addr
+}
+
+type addr struct {
+	remoteAddr string
+}
+
+func (a addr) Network() string {
+	panic("implement me")
+}
+
+func (a addr) String() string {
+	return a.remoteAddr
+}
+
+func (c contextWriteCloser) CloseWrite() error {
+	panic("implement me")
+}
+
+func (c contextWriteCloser) RemoteAddr() net.Addr { return c.addr }
+
+func (c contextWriteCloser) Context() context.Context {
+	return context.Background()
+}