Implemet multicast protocol

bootserver/filelock/filelock.go

@@ -38,6 +38,7 @@ func (fl *FileLock) Lock(timeout time.Duration) error {
 			if _, err := os.Create(fl.lockPath); err != nil {
 				return fmt.Errorf("failed to create lock: %w", err)
 			}
+			return nil
 		}
 		if time.Now().After(end) {
 			return ErrLocked

bootserver/main.go

@@ -10,6 +10,7 @@ import (
 	"git.faercol.me/faercol/http-boot-server/bootserver/config"
 	"git.faercol.me/faercol/http-boot-server/bootserver/logger"
 	"git.faercol.me/faercol/http-boot-server/bootserver/server"
+	"git.faercol.me/faercol/http-boot-server/bootserver/services"
 	"git.faercol.me/faercol/http-boot-server/bootserver/udplistener"
 )
 
@@ -42,6 +43,9 @@ func main() {
 	logger.Init(conf.LogLevel)
 	logger.L.Infof("Initialized logger with level %v", conf.LogLevel)
 
+	logger.L.Info("Initializing data access service")
+	services.NewClientHandlerService(conf.DataFilepath, logger.L).Init()
+
 	logger.L.Info("Initializing server")
 	s, err := server.New(conf, logger.L)
 	if err != nil {
@@ -49,7 +53,7 @@ func main() {
 	}
 
 	logger.L.Info("Initializing UDP listener")
-	listener, err := udplistener.New(conf.UDPIface, conf.UPDMcastGroup, conf.UDPPort, logger.L)
+	listener, err := udplistener.New(conf, logger.L)
 	if err != nil {
 		logger.L.Fatalf("Failed to initialize UDP listener: %s", err.Error())
 	}

bootserver/services/services.go

@@ -35,16 +35,17 @@ func NewClientHandlerService(filepath string, logger *logrus.Logger) *ClientHand
 	}
 }
 
-func (chs *ClientHandlerService) init() {
+func (chs *ClientHandlerService) Init() {
 	if _, err := os.Open(chs.filepath); errors.Is(err, os.ErrNotExist) {
-		if err := os.WriteFile(chs.filepath, nil, 0o644); err != nil {
+		if err := os.WriteFile(chs.filepath, []byte("{}"), 0o644); err != nil {
 			panic(fmt.Errorf("failed to init data file: %w", err))
 		}
 	}
+	chs.fileLock.Unlock()
 }
 
 func (chs *ClientHandlerService) unload(conf map[uuid.UUID]*bootoption.Client) error {
-	dat, err := json.Marshal(conf)
+	dat, err := json.MarshalIndent(conf, "", "\t")
 	if err != nil {
 		return fmt.Errorf("failed to marshal data to JSON: %w", err)
 	}
@@ -67,9 +68,11 @@ func (chs *ClientHandlerService) load() (map[uuid.UUID]*bootoption.Client, error
 
 	dat, err := os.ReadFile(chs.filepath)
 	if err != nil {
+		defer chs.fileLock.Unlock()
 		return nil, fmt.Errorf("failed to read data file: %w", err)
 	}
 	if err := json.Unmarshal(dat, &conf); err != nil {
+		defer chs.fileLock.Unlock()
 		return nil, fmt.Errorf("failed to parse data file: %w", err)
 	}
 	return conf, nil

bootserver/udplistener/udplistener.go

@@ -3,10 +3,12 @@ package udplistener
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"net"
 
 	"git.faercol.me/faercol/http-boot-server/bootserver/bootprotocol"
+	"git.faercol.me/faercol/http-boot-server/bootserver/config"
 	"git.faercol.me/faercol/http-boot-server/bootserver/services"
 	"github.com/sirupsen/logrus"
 )
@@ -28,21 +30,22 @@ type UDPListener struct {
 	cancel  context.CancelFunc
 }
 
-func New(ifaceName, multicastGroup string, port int, log *logrus.Logger) (*UDPListener, error) {
+func New(conf *config.AppConfig, log *logrus.Logger) (*UDPListener, error) {
-	addr, err := net.ResolveUDPAddr("udp", fmt.Sprintf("[%s]:%d", multicastGroup, port))
+	addr, err := net.ResolveUDPAddr("udp", fmt.Sprintf("[%s]:%d", conf.UPDMcastGroup, conf.UDPPort))
 	if err != nil {
 		return nil, fmt.Errorf("failed to resolve UDP address: %w", err)
 	}
 
-	iface, err := net.InterfaceByName(ifaceName)
+	iface, err := net.InterfaceByName(conf.UDPIface)
 	if err != nil {
-		return nil, fmt.Errorf("failed to resolve interface name %s: %w", ifaceName, err)
+		return nil, fmt.Errorf("failed to resolve interface name %s: %w", conf.UDPIface, err)
 	}
 
 	return &UDPListener{
 		addr:    addr,
 		iface:   iface,
 		ctx:     context.TODO(),
+		service: services.NewClientHandlerService(conf.DataFilepath, log),
 		log:     log,
 	}, nil
 }
@@ -57,6 +60,56 @@ func (l *UDPListener) Init() error {
 	return nil
 }
 
+func (l *UDPListener) handleBootRequest(msg bootprotocol.Message, subLogger logrus.FieldLogger) bootprotocol.Message {
+	subLogger.Debugf("Processing message %q", msg.String())
+	requestLogger := subLogger.WithField("clientID", msg.ID().String())
+	requestLogger.Debug("Getting boot option for client")
+
+	bootOption, err := l.service.GetClientSelectedBootOption(msg.ID())
+	if err != nil {
+		if errors.Is(err, services.ErrUnknownClient) || errors.Is(err, services.ErrUnselectedBootOption) {
+			requestLogger.Warnf("Client is not configured, returning an error (original error is %q)", err.Error())
+			return bootprotocol.Deny(msg.ID(), "client not configured")
+		}
+		if errors.Is(err, services.ErrUnknownBootOption) {
+			requestLogger.Errorf("Invalid config for client: %s", err.Error())
+			return bootprotocol.Deny(msg.ID(), "invalid client config")
+		}
+		requestLogger.Errorf("Failed to get config for client: %s", err.Error())
+		return bootprotocol.Deny(msg.ID(), "unknown server error")
+	}
+	return bootprotocol.Accept(msg.ID(), bootOption.Path)
+}
+
+func (l *UDPListener) handleClient(msg *udpMessage) error {
+	clientLogger := l.log.WithField("clientIP", msg.sourceAddr.IP)
+
+	clientLogger.Debug("Handling request for client")
+	response := l.handleBootRequest(msg.message, clientLogger)
+
+	clientLogger.Debug("Dialing client for answer")
+	con, err := net.DialUDP("udp", nil, msg.sourceAddr)
+	if err != nil {
+		return fmt.Errorf("failed to dialed client: %w", err)
+	}
+	defer con.Close()
+
+	clientLogger.Debug("Sending response to client")
+	dat, err := response.MarshalBinary()
+	if err != nil {
+		return fmt.Errorf("failed to marshal response to bytes, %w", err)
+	}
+
+	n, err := con.Write(dat)
+	if err != nil {
+		return fmt.Errorf("failed to send response to client, %w", err)
+	}
+	if n != len(dat) {
+		return fmt.Errorf("failed to send the entire response to client (%d/%d)", n, len(dat))
+	}
+	return nil
+}
+
 func (l *UDPListener) listen() (*udpMessage, error) {
 	buffer := make([]byte, bufferLength)
 	n, source, err := l.l.ReadFromUDP(buffer)
@@ -101,7 +154,9 @@ func (l *UDPListener) mainLoop() {
 		case err := <-errChan:
 			l.log.Error(err)
 		case msg := <-msgChan:
-			l.log.Infof("Request from %s: %q", msg.sourceAddr.String(), msg.message.String())
+			if err := l.handleClient(msg); err != nil {
+				l.log.Errorf("Failed to handle message from client: %q", err.Error())
+			}
 		}
 
 	}