Improve configuration

README.md

@@ -1,4 +1,4 @@
-# PNDPD - NDP Responder / Proxy (IPv6)
+# PNDPD - NDP Proxy / Responder (IPv6)
 ## Features
 - **Efficiently** process incoming packets using bpf (which runs in the kernel)
 - **Proxy** NDP between interfaces with an optional whitelist

config.go

@@ -12,62 +12,90 @@ import (
 func readConfig(dest string) {
 	file, err := os.Open(dest)
 	if err != nil {
-		fmt.Println("Error:", err.Error())
-		os.Exit(1)
+		configFatalError(err, "")
 	}
-	defer func(file *os.File) {
-		_ = file.Close()
-	}(file)
+	var (
+		currentOption string
+		blockMap      map[string][]string
+	)
 
 	scanner := bufio.NewScanner(file)
-
 	for scanner.Scan() {
 		line := scanner.Text()
-		if strings.HasPrefix(line, "//") || strings.TrimSpace(line) == "" {
+		line, _, _ = strings.Cut(line, "//")
+		line = strings.TrimSpace(line)
+		if line == "" {
 			continue
 		}
-		if strings.HasPrefix(line, "debug") {
-			if strings.Contains(line, "on") {
+
+		if after, found := strings.CutPrefix(line, "debug"); found {
+			if strings.TrimSpace(after) == "on" {
 				pndp.GlobalDebug = true
 				fmt.Println("DEBUG ON")
 			}
 			continue
 		}
 
-		if strings.HasSuffix(line, "{") {
-			option := strings.TrimSuffix(strings.TrimSpace(line), "{")
-			option = strings.TrimSpace(option)
-			module, command := modules.GetCommand(option, modules.Config)
-			var lines = make([]string, 0)
-			if module != nil {
-				for {
-					if !scanner.Scan() {
-						break
-					}
-					line := strings.TrimSpace(scanner.Text())
-					if strings.Contains(line, "}") {
-						break
-					}
+		if option, after, found := strings.Cut(line, "{"); found {
+			if after != "" {
+				configFatalError(nil, "Nothing may follow after '{'. A new line must be used")
+			}
+			if blockMap != nil {
+				configFatalError(nil, "A new '{' block was started before the previous one was closed")
+			}
+			currentOption = strings.TrimSpace(option)
+			blockMap = make(map[string][]string)
+			continue
+		}
 
-					lines = append(lines, line)
-				}
-				modules.ExecuteInit(module, modules.CallbackInfo{
-					CallbackType: modules.Config,
-					Command:      command,
-					Arguments:    lines,
-				})
+		if before, after, found := strings.Cut(line, "}"); found {
+			if after != "" || before != "" {
+				configFatalError(nil, "Nothing may precede or follow '}'. A new line must be used")
+			}
+			if blockMap == nil {
+				configFatalError(nil, "Found a '}' tag without a matching '{' tag.")
+			}
+			module, command := modules.GetCommand(currentOption, modules.Config)
+			if module == nil {
+				configFatalError(nil, "Unknown configuration block: "+currentOption)
 			}
+			modules.ExecuteInit(module, modules.CallbackInfo{
+				CallbackType: modules.Config,
+				Command:      command,
+				Config:       blockMap,
+			})
+			blockMap = nil
+			continue
 		}
 
+		if blockMap != nil {
+			kv := strings.SplitN(line, " ", 2)
+			if len(kv) != 2 {
+				configFatalError(nil, "Key without value")
+			}
+			if blockMap[kv[0]] == nil {
+				blockMap[kv[0]] = make([]string, 0)
+			}
+			blockMap[kv[0]] = append(blockMap[kv[0]], kv[1])
+		}
 	}
+	_ = file.Close()
+
 	if modules.ExistsBlockingModule() {
 		modules.ExecuteComplete()
 		waitForSignal()
 		modules.ShutdownAll()
 	}
 
 	if err := scanner.Err(); err != nil {
-		panic(err)
+		configFatalError(err, "")
 	}
+}
 
+func configFatalError(err error, explanation string) {
+	fmt.Println("Error reading config file:", explanation)
+	if err != nil {
+		fmt.Println(err)
+	}
+	os.Exit(1)
 }

modules/modules.go

@@ -29,6 +29,7 @@ type CallbackInfo struct {
 	CallbackType CallbackType
 	Command      Command
 	Arguments    []string
+	Config       map[string][]string
 }
 
 func RegisterModule(name string, commands []Command, initCallback func(CallbackInfo), CompleteCallback func(), shutdownCallback func()) {

modules/userInterface/userInterface.go

@@ -121,31 +121,21 @@ func initCallback(callback modules.CallbackInfo) {
 		switch callback.Command.CommandText {
 		case "proxy":
 			obj := configProxy{}
+			obj.Iface1 = getDefaultConfValue(callback.Config["ext-iface"])
+			obj.Iface2 = getDefaultConfValue(callback.Config["int-iface"])
+			obj.autosense = getDefaultConfValue(callback.Config["autosense"])
+			obj.DontMonitorInterfaces = getDefaultConfValue(callback.Config["monitor-changes"]) == "off"
+
 			filter := ""
-			for _, n := range callback.Arguments {
-				if strings.HasPrefix(n, "ext-iface") {
-					obj.Iface1 = strings.TrimSpace(strings.TrimPrefix(n, "ext-iface"))
-				}
-				if strings.HasPrefix(n, "int-iface") {
-					obj.Iface2 = strings.TrimSpace(strings.TrimPrefix(n, "int-iface"))
-				}
-				if strings.HasPrefix(n, "filter") {
-					filter += strings.TrimSpace(strings.TrimPrefix(n, "filter")) + ";"
-					if strings.Contains(n, ";") {
-						showError("config: the use of semicolons is not allowed in the filter arguments")
-					}
-				}
-				if strings.HasPrefix(n, "autosense") {
-					obj.autosense = strings.TrimSpace(strings.TrimPrefix(n, "autosense"))
-				}
-				if strings.HasPrefix(n, "monitor-changes") {
-					obj.DontMonitorInterfaces = strings.TrimSpace(strings.TrimPrefix(n, "monitor-changes")) == "off"
-				}
-				if strings.Contains(n, "//") {
-					showError("config: comments are not allowed after arguments")
+			for i := range callback.Config["filter"] {
+				value := callback.Config["filter"][i]
+				if strings.Contains(value, ";") {
+					showError("config: the use of semicolons is not allowed in the filter arguments")
 				}
+				filter += value + ";"
 			}
 			obj.Filter = strings.TrimSuffix(filter, ";")
+
 			if obj.autosense != "" && obj.Filter != "" {
 				showError("config: cannot have both a filter and autosense enabled on a proxy object")
 			}
@@ -155,40 +145,40 @@ func initCallback(callback modules.CallbackInfo) {
 			allProxies = append(allProxies, &obj)
 		case "responder":
 			obj := configResponder{}
+			obj.Iface = getDefaultConfValue(callback.Config["iface"])
+			obj.autosense = getDefaultConfValue(callback.Config["autosense"])
+			obj.DontMonitorInterfaces = getDefaultConfValue(callback.Config["monitor-changes"]) == "off"
 			filter := ""
-			for _, n := range callback.Arguments {
-				if strings.HasPrefix(n, "iface") {
-					obj.Iface = strings.TrimSpace(strings.TrimPrefix(n, "iface"))
-				}
-				if strings.HasPrefix(n, "filter") {
-					filter += strings.TrimSpace(strings.TrimPrefix(n, "filter")) + ";"
-					if strings.Contains(n, ";") {
-						showError("config: the use of semicolons is not allowed in the filter arguments")
-					}
-				}
-				if strings.HasPrefix(n, "autosense") {
-					obj.autosense = strings.TrimSpace(strings.TrimPrefix(n, "autosense"))
-				}
-				if obj.autosense != "" && obj.Filter != "" {
-					showError("config: cannot have both a filter and autosense enabled on a responder object")
-				}
-				if obj.Iface == "" {
-					showError("config: interface not specified in the responder object. (iface parameter)")
-				}
-				if strings.HasPrefix(n, "monitor-changes") {
-					obj.DontMonitorInterfaces = strings.TrimSpace(strings.TrimPrefix(n, "monitor-changes")) == "off"
-				}
-				if strings.Contains(n, "//") {
-					showError("config: comments are not allowed after arguments")
+			for i := range callback.Config["filter"] {
+				value := callback.Config["filter"][i]
+				if strings.Contains(value, ";") {
+					showError("config: the use of semicolons is not allowed in the filter arguments")
 				}
+				filter += value + ";"
 			}
 			obj.Filter = strings.TrimSuffix(filter, ";")
-			allResponders = append(allResponders, &obj)
 
+			if obj.autosense != "" && obj.Filter != "" {
+				showError("config: cannot have both a filter and autosense enabled on a responder object")
+			}
+			if obj.Iface == "" {
+				showError("config: interface not specified in the responder object. (iface parameter)")
+			}
+			allResponders = append(allResponders, &obj)
 		}
 	}
 }
 
+func getDefaultConfValue(in []string) string {
+	if in == nil {
+		return ""
+	}
+	if len(in) == 0 {
+		return ""
+	}
+	return in[0]
+}
+
 func completeCallback() {
 	for _, n := range allProxies {
 		o := pndp.NewProxy(n.Iface1, n.Iface2, pndp.ParseFilter(n.Filter), n.autosense, !n.DontMonitorInterfaces)
@@ -201,6 +191,7 @@ func completeCallback() {
 		o.Start()
 	}
 }
+
 func shutdownCallback() {
 	for _, n := range allProxies {
 		n.instance.Stop()

pndpd.conf

@@ -2,12 +2,12 @@
 
 // Proxy example with autoconfigured allow-list
 // The allow-list of IP addresses to proxy is configured based
-// on the addresses assigned to the interface specified via the autosense parameter.
+// on the networks assigned to the interface specified via the autosense parameter.
 // This works even if the IP addresses change frequently.
 proxy {
     ext-iface eth0
     int-iface eth1
-    autosense eth1
+    autosense eth1 // If eth1 has fd01::1/64 assigned to it, then fd01::/64 will be configured as an allow-list
     // Disable monitor-changes only if the IP addresses assigned to the specified interfaces never change (with the exception of the autosense interface)
     // monitor-changes on
 }
@@ -28,11 +28,11 @@ proxy {
 // Responder example with autoconfigured allow-list (Not recommended - prefer using proxy mode)
 // Create an NDP responder that listens and responds on interface "eth0"
 // The allow-list of IP addresses to proxy is configured based
-// on the addresses assigned to the interface specified via the autosense parameter.
+// on the networks assigned to the interface specified via the autosense parameter.
 // This works even if the IP addresses change frequently.
 responder {
     iface eth0
-    autosense eth0
+    autosense eth0 // If eth0 has fd01::1/64 assigned to it, then fd01::/64 will be configured as an allow-list
     // Disable monitor-changes only if the IP addresses assigned to the specified interfaces never change (with the exception of the autosense interface)
     // monitor-changes on
 }