WIP: replace the backend address related fields/API from udp config, move them to backend udp

abstract/abstract.go

@@ -17,7 +17,6 @@ package abstract
 */
 
 import (
-	"net"
 	"time"
 )
 
@@ -47,5 +46,4 @@ type TCPConnectionConfig interface {
 type UDPConnectionConfig interface {
 	ConnectionConfig
 	Timeout() time.Duration
-	BackendAddr() net.Addr
 }

backend_udp.go

@@ -27,6 +27,7 @@ type backendUDP struct {
 	cfg         abstract.UDPConnectionConfig
 	bufPool     *BufPool
 	msgChan     chan udpMessage
+	backendAddr *net.UDPAddr
 }
 
 type udpMessage struct {
@@ -42,7 +43,16 @@ func (r udpRel) String() string {
 	return r.clientAddr
 }
 
-func initUDP(wg *sync.WaitGroup, ctx context.Context, bp *BufPool, cfg abstract.UDPConnectionConfig, client net.PacketConn) *backendUDP {
+func initUDP(wg *sync.WaitGroup, ctx context.Context, bp *BufPool, cfg abstract.UDPConnectionConfig, client net.PacketConn) (*backendUDP, error) {
+	var (
+		addr *net.UDPAddr
+		err  error
+	)
+
+	if addr, err = net.ResolveUDPAddr("udp", cfg.Backend()); err != nil {
+		return nil, fmt.Errorf("failed to resolve UDP address: %v", err)
+	}
+
 	backend := &backendUDP{
 		relations:   make(map[string]udpRel),
 		relMtx:      new(sync.Mutex),
@@ -50,9 +60,11 @@ func initUDP(wg *sync.WaitGroup, ctx context.Context, bp *BufPool, cfg abstract.
 		client:      client,
 		msgChan:     make(chan udpMessage),
 		bufPool:     bp,
+		backendAddr: addr,
 	}
 	defer wg.Done()
 
+	//TODO: make the number of handler spawn configurable
 	wg.Add(1)
 	handlerSpawn(wg, ctx, backend)
 
@@ -65,7 +77,7 @@ func initUDP(wg *sync.WaitGroup, ctx context.Context, bp *BufPool, cfg abstract.
 	wg.Add(1)
 	handlerSpawn(wg, ctx, backend)
 
-	return backend
+	return backend, nil
 }
 
 func handlerSpawn(wg *sync.WaitGroup, ctx context.Context, backend *backendUDP) {
@@ -115,7 +127,7 @@ func (b *backendUDP) addUpdateRel(clientAddr string, rel udpRel) {
 
 func (b *backendUDP) createRelSend(clientAddr string, buf []byte) (udpRel, error) {
 	var (
-		udpAddr *net.UDPAddr
+		laddr   *net.UDPAddr
 		udpConn *net.UDPConn
 		err     error
 	)
@@ -124,15 +136,15 @@ func (b *backendUDP) createRelSend(clientAddr string, buf []byte) (udpRel, error
 		clientAddr: clientAddr,
 	}
 
-	if udpAddr, err = net.ResolveUDPAddr("udp", b.cfg.Backend()); err != nil {
+	if laddr, err = net.ResolveUDPAddr("udp", ""); err != nil {
-		return rel, fmt.Errorf("create udp relation and send message: resolve udp addr: %w", err)
+		return rel, fmt.Errorf("create udp relation and send message: resolve local/self address for UDP: %w", err)
 	}
 
-	if udpConn, err = net.DialUDP("udp", nil, udpAddr); err != nil {
+	if udpConn, err = net.ListenUDP("udp", laddr); err != nil {
-		return rel, fmt.Errorf("create udp relation and send message: dial udp: %w", err)
+		return rel, fmt.Errorf("create udp relation and send message: bind local/self address for UDP: %w", err)
 	}
 
-	if _, err = udpConn.WriteTo(buf, b.cfg.BackendAddr()); err != nil {
+	if _, err = udpConn.WriteTo(buf, b.backendAddr); err != nil {
 		if errors.Is(err, net.ErrClosed) {
 			return rel, fmt.Errorf("create udp relation and send message: write udp: %w", err)
 		}
@@ -152,7 +164,7 @@ func (b *backendUDP) relSend(rel udpRel, buf []byte) error {
 		err error
 	)
 
-	if n, err = rel.backend.WriteTo(buf, b.cfg.BackendAddr()); err != nil && n == 0 {
+	if n, err = rel.backend.WriteTo(buf, b.backendAddr); err != nil && n == 0 {
 		return fmt.Errorf("relSend: %w", err)
 	}
 
@@ -199,7 +211,7 @@ func (b *backendUDP) Send(ctx context.Context, addr string, p []byte) error {
 		n int
 	)
 
-	buf := b.bufPool.Get() // the buf will be released in handle
+	buf := b.bufPool.Get() // the buf will be released in the handle
 	n = copy(buf, p)
 
 	if len(p) != n {
@@ -261,8 +273,8 @@ udpBackendLoop:
 		}
 
 		if wn, err = b.client.WriteTo(buf[:n], rel); err != nil {
-			// in case of error, never close b.client, it's a shared Packet Conn.
+			// In case of error, never close b.client, it's a shared Packet Conn.
-			// All UDP relation use a shared connection/socket back to the client
+			// All UDP relations use a shared connection/socket back to the client
 			if errors.Is(err, net.ErrClosed) {
 				rel.ctxCancel()
 				break udpBackendLoop

bounce.go

@@ -136,7 +136,7 @@ func RunTCP(wg *sync.WaitGroup, ctx context.Context, bp *BufPool, cfg abstract.T
 	)
 
 	if l, err = net.Listen("tcp", cfg.Listen()); err != nil {
-		panic(fmt.Errorf("failed to listen tcp: %w", err))
+		log.Panic().Caller().Err(err).Msg("listen tcp")
 	}
 
 	accepted = make(chan net.Conn)
@@ -365,11 +365,13 @@ func RunUDP(wg *sync.WaitGroup, ctx context.Context, bp *BufPool, cfg abstract.U
 	)
 
 	if client, err = net.ListenPacket("udp", cfg.Listen()); err != nil {
-		panic(fmt.Errorf("failed to bind for UDP %s: %w", cfg.Name(), err))
+		log.Panic().Err(err).Msgf("failed to bind for UDP %s", cfg.Listen())
 	}
 
 	wg.Add(1)
-	backend = initUDP(wg, ctx, bp, cfg, client)
+	if backend, err = initUDP(wg, ctx, bp, cfg, client); err != nil {
+		log.Panic().Caller().Err(err).Msg("failed to init UDP")
+	}
 	buf = bp.Get()
 	defer bp.Put(buf)
 

cmd/test-client/main.go

@@ -125,10 +125,9 @@ func sendUDP(ctx context.Context) {
 	if laddr, err = net.ResolveUDPAddr(UDP, ""); err != nil {
 		log.Fatal().Caller().Err(err).Str(SERVER, viper.GetString(SERVER)).Msg("udp resolve local/self address")
 	}
-	//TODO: log address to be bound by client
+	log.Info().Str(SERVER, viper.GetString(SERVER)).Msgf("bound address %v", laddr)
 
-	//TODO: use un-connected socket of UDP, replace all net.DialUDP() with net.ListenUDP()
+	// In Go, binding address and port for UDP use ListenUDP. Confusing!!
-	// In Go, binding for UDP using ListenUDP. Confusing!!
 	if conn, err = net.ListenUDP(UDP, laddr); err != nil {
 		log.Fatal().Caller().Err(err).Str(SERVER, viper.GetString(SERVER)).Msg("fail to bind local/self address")
 	}

config/udp.go

@@ -18,7 +18,6 @@ package config
 
 import (
 	"fmt"
-	"net"
 	"time"
 
 	"gitea.suyono.dev/suyono/netbounce/abstract"
@@ -68,15 +67,3 @@ func (u udpModule) Backend() string {
 func (u udpModule) Timeout() time.Duration {
 	return u.config.Timeout
 }
-
-func (u udpModule) BackendAddr() net.Addr {
-	return udpBackendAddr(u)
-}
-
-func (a udpBackendAddr) Network() string {
-	return "udp"
-}
-
-func (a udpBackendAddr) String() string {
-	return a.config.Backend
-}