Support for NTLM authentication added (#109)

* Support for NTLM authentication added

To support NTLM authentication, a database is added as an authentication source.
Currently, only the configuration file is supported as a database.
Database authentication supports Basic and NTLM authentication protcols.

ServerConfig.BasicAuthEnabled renamed to LocalEnabled as Basic auth can be used with NTLM or Local.

cmd/auth/database/config.go

@@ -0,0 +1,25 @@
+package database
+
+import (
+	"github.com/bolkedebruin/rdpgw/cmd/auth/config"
+)
+
+type Config struct {
+	users map[string]config.UserConfig
+}
+
+func NewConfig(users []config.UserConfig) *Config {
+        usersMap := map[string]config.UserConfig{}
+                
+        for _, user := range users {
+                usersMap[user.Username] = user
+        }
+        
+	return &Config{
+		users: usersMap,
+	}
+}
+
+func (c *Config) GetPassword (username string) string {
+        return c.users[username].Password
+}

cmd/auth/database/config_test.go

@@ -0,0 +1,43 @@
+package database
+
+import (
+	"github.com/bolkedebruin/rdpgw/cmd/auth/config"
+	"testing"
+)
+
+func createTestDatabase () (Database) {
+	var users = []config.UserConfig{}
+
+	user1 := config.UserConfig{}
+	user1.Username = "my_username"
+	user1.Password = "my_password"
+	users = append(users, user1)
+
+	user2 := config.UserConfig{}
+	user2.Username = "my_username2"
+	user2.Password = "my_password2"
+	users = append(users, user2)
+
+	config := NewConfig(users)
+
+	return config
+}
+
+func TestDatabaseConfigValidUsername(t *testing.T) {
+	database := createTestDatabase()
+
+	if database.GetPassword("my_username") != "my_password" {
+		t.Fatalf("Wrong password returned")
+	}
+	if database.GetPassword("my_username2") != "my_password2" {
+		t.Fatalf("Wrong password returned")
+	}
+}
+
+func TestDatabaseInvalidUsername(t *testing.T) {
+	database := createTestDatabase()
+
+	if database.GetPassword("my_invalid_username") != "" {
+		t.Fatalf("Non empty password returned for invalid username")
+	}
+}

cmd/auth/database/database.go

@@ -0,0 +1,5 @@
+package database
+
+type Database interface {
+        GetPassword (username string) string
+}