Make ip address of both local and remote optional

This change makes the ip address of both `-local` and `-remote` optional
setting their value to `127.0.0.1` if not given.

Author: David Pinheiro

README.md

@@ -54,4 +54,24 @@ INFO[0000] listening on local address                    local_address="127.0.0.
 $ mole -remote 172.17.0.100:80 -server example1 
 INFO[0000] listening on local address                    local_address="127.0.0.1:61305"
 ```
+### Bind the local address to 127.0.0.1 by specifying only the local port
 
+```sh
+$ mole -v -local :8080 -remote 172.17.0.100:80 -server example1
+DEBU[0000] cli options                                   key= local="127.0.0.1:8080" remote="172.17.0.100:80" server=example1 v=true
+DEBU[0000] using ssh config file from: /home/mole/.ssh/config
+DEBU[0000] server: [name=example1, address=10.0.0.12:2222, user=user, key=/home/mole/.ssh/id_rsa]
+DEBU[0000] tunnel: [local:127.0.0.1:8080, server:10.0.0.12:2222, remote:172.17.0.100:80]
+INFO[0000] listening on local address                    local_address="127.0.0.1:8080"
+```
+
+### Connect to a remote ip address 127.0.0.1 by specifying only the remote port
+
+```sh
+$ mole -v -local 127.0.0.1:8080 -remote :80 -server example1
+DEBU[0000] cli options                                   key= local="127.0.0.1:8080" remote="127.0.0.1:80" server=example1 v=true
+DEBU[0000] using ssh config file from: /home/mole/.ssh/config
+DEBU[0000] server: [name=example1, address=10.0.0.12:2222, user=user, key=/home/mole/.ssh/id_rsa]
+DEBU[0000] tunnel: [local:127.0.0.1:8080, server:10.0.0.12:2222, remote:127.0.0.1:80]
+INFO[0000] listening on local address                    local_address="127.0.0.1:8080"
+```

cmd/mole/main.go

@@ -29,7 +29,7 @@ func (f hostFlag) String() string {
 }
 
 func (f *hostFlag) Set(value string) error {
-	re := regexp.MustCompile("(?P<user>.+@)?(?P<host>[0-9a-zA-Z.-]+)(?P<port>:[0-9]+)?")
+	re := regexp.MustCompile("(?P<user>.+@)?(?P<host>[0-9a-zA-Z\\.-]+)?(?P<port>:[0-9]+)?")
 
 	match := re.FindStringSubmatch(value)
 	result := make(map[string]string)
@@ -41,10 +41,6 @@ func (f *hostFlag) Set(value string) error {
 		result[name] = match[i]
 	}
 
-	if result["host"] == "" {
-		return fmt.Errorf("error parsing argument. Host must be provided.")
-	}
-
 	f.User = strings.Trim(result["user"], "@")
 	f.Host = result["host"]
 	f.Port = strings.Trim(result["port"], ":")
@@ -73,11 +69,11 @@ var (
 )
 
 func init() {
-	flag.Var(&localFlag, "local", "set local endpoint address: <host>:<port>")
-	flag.Var(&remoteFlag, "remote", "set remote endpoing address: <host>:<port>")
+	flag.Var(&localFlag, "local", "(optional) Set local endpoint address: [<host>]:<port>")
+	flag.Var(&remoteFlag, "remote", "set remote endpoing address: [<host>]:<port>")
 	flag.Var(&serverFlag, "server", "set server address: [<user>@]<host>[:<port>]")
-	flag.StringVar(&keyFlag, "key", "", "set server authentication key file path")
-	flag.BoolVar(&vFlag, "v", false, "increase log verbosity")
+	flag.StringVar(&keyFlag, "key", "", "(optional) Set server authentication key file path")
+	flag.BoolVar(&vFlag, "v", false, "(optional) Increase log verbosity")
 	flag.BoolVar(&helpFlag, "help", false, "list all options available")
 	flag.BoolVar(&versionFlag, "version", false, "display the mole version")
 }
@@ -150,7 +146,7 @@ func handleCLIOptions() int {
 
 func usage() string {
 	return `usage:
-  mole [-v] [-local <host>:<port>] -remote <host>:<port> -server [<user>@]<host>[:<port>] [-key <key_path>]
+  mole [-v] [-local [<host>]:<port>] -remote [<host>]:<port> -server [<user>@]<host>[:<port>] [-key <key_path>]
   mole -help
   mole -version
 	`

tunnel/tunnel.go

@@ -86,7 +86,7 @@ func NewServer(user, address, key string) (*Server, error) {
 	}, nil
 }
 
-// String provided a string representation os a Server.
+// String provided a string representation of a Server.
 func (s Server) String() string {
 	return fmt.Sprintf("[name=%s, address=%s, user=%s, key=%s]", s.Name, s.Address, s.User, s.Key)
 }
@@ -105,6 +105,12 @@ func New(localAddress string, server *Server, remoteAddress string) *Tunnel {
 
 	if localAddress == "" {
 		localAddress = "127.0.0.1:0"
+	} else if strings.HasPrefix(localAddress, ":") {
+		localAddress = fmt.Sprintf("127.0.0.1%s", localAddress)
+	}
+
+	if strings.HasPrefix(remoteAddress, ":") {
+		remoteAddress = fmt.Sprintf("127.0.0.1%s", remoteAddress)
 	}
 
 	return &Tunnel{

tunnel/tunnel_test.go

@@ -31,11 +31,11 @@ func TestServerOptions(t *testing.T) {
 	}{
 		{
 			"mole_user",
-			"127.0.0.1:2222",
+			"172.17.0.10:2222",
 			"testdata/.ssh/id_rsa",
 			&Server{
-				Name:    "127.0.0.1",
-				Address: "127.0.0.1:2222",
+				Name:    "172.17.0.10",
+				Address: "172.17.0.10:2222",
 				User:    "mole_user",
 				Key:     "testdata/.ssh/id_rsa",
 			},
@@ -88,6 +88,65 @@ func TestServerOptions(t *testing.T) {
 
 }
 
+func TestTunnelOptions(t *testing.T) {
+	server := &Server{Name: "s"}
+	tests := []struct {
+		local    string
+		server   *Server
+		remote   string
+		expected *Tunnel
+	}{
+		{
+			"172.17.0.10:2222",
+			server,
+			"172.17.0.10:2222",
+			&Tunnel{
+				local:  "172.17.0.10:2222",
+				server: server,
+				remote: "172.17.0.10:2222",
+			},
+		},
+		{
+			"",
+			server,
+			"172.17.0.10:2222",
+			&Tunnel{
+				local:  "127.0.0.1:0",
+				server: server,
+				remote: "172.17.0.10:2222",
+			},
+		},
+		{
+			":8443",
+			server,
+			":443",
+			&Tunnel{
+				local:  "127.0.0.1:8443",
+				server: server,
+				remote: "127.0.0.1:443",
+			},
+		},
+	}
+
+	for _, test := range tests {
+		tun := New(test.local, test.server, test.remote)
+
+		if test.expected.local != tun.local {
+			t.Errorf("unexpected local result : expected: %s, result: %s", test.expected, tun)
+		}
+
+		if test.expected.remote != tun.remote {
+			t.Errorf("unexpected remote result : expected: %s, result: %s", test.expected, tun)
+		}
+
+		if !reflect.DeepEqual(test.expected.server, tun.server) {
+			t.Errorf("unexpected server result : expected: %s, result: %s", test.expected, tun)
+		}
+
+	}
+
+}
+
 func TestTunnel(t *testing.T) {
 	expected := "ABC"
 	c := prepareTunnel(t)