reply to LkUp

main.go

@@ -278,7 +278,7 @@ func main() {
 					rtmpCh <- ddpkt
 
 				case 2: // The NIS (name information socket / NBP socket)
-					if err := handleNBP(pcapHandle, myHWAddr, cfg, ddpkt); err != nil {
+					if err := handleNBP(pcapHandle, myHWAddr, ethFrame.Src, myAddr, cfg, ddpkt); err != nil {
 						log.Printf("NBP: Couldn't handle: %v", err)
 					}
 
@@ -434,7 +434,7 @@ func main() {
 	}
 }
 
-func handleNBP(pcapHandle *pcap.Handle, myHWAddr ethernet.Addr, cfg *config, ddpkt *ddp.ExtPacket) error {
+func handleNBP(pcapHandle *pcap.Handle, myHWAddr, srcHWAddr ethernet.Addr, myAddr aarp.AddrPair, cfg *config, ddpkt *ddp.ExtPacket) error {
 	if ddpkt.Proto != ddp.ProtoNBP {
 		return fmt.Errorf("invalid DDP type %d on socket 2", ddpkt.Proto)
 	}
@@ -446,47 +446,97 @@ func handleNBP(pcapHandle *pcap.Handle, myHWAddr ethernet.Addr, cfg *config, ddp
 
 	log.Printf("NBP: Got %v id %d with tuples %v", nbpkt.Function, nbpkt.NBPID, nbpkt.Tuples)
 
-	// Is it a BrRq?
-	if nbpkt.Function != nbp.FunctionBrRq {
-		return nil
-	}
+	switch nbpkt.Function {
+	case nbp.FunctionLkUp:
+		// when in AppleTalk, do as Apple Internet Router does...
+		tuple := nbpkt.Tuples[0]
+		if tuple.Object != "jrouter" && tuple.Object != "=" {
+			return nil
+		}
+		if tuple.Type != "AppleRouter" && tuple.Type != "=" {
+			return nil
+		}
+		if tuple.Zone != cfg.EtherTalk.ZoneName && tuple.Zone != "*" && tuple.Zone != "" {
+			return nil
+		}
+		respPkt := &nbp.Packet{
+			Function: nbp.FunctionLkUpReply,
+			NBPID:    nbpkt.NBPID,
+			Tuples: []nbp.Tuple{
+				{
+					Network:    myAddr.Proto.Network,
+					Node:       myAddr.Proto.Node,
+					Socket:     253,
+					Enumerator: 0,
+					Object:     "jrouter",
+					Type:       "AppleRouter",
+					Zone:       cfg.EtherTalk.ZoneName,
+				},
+			},
+		}
+		respRaw, err := respPkt.Marshal()
+		if err != nil {
+			return fmt.Errorf("couldn't marshal LkUp-Reply: %v", err)
+		}
+		ddpkt.DstNet = ddpkt.SrcNet
+		ddpkt.DstNode = ddpkt.SrcNode
+		ddpkt.DstSocket = ddpkt.SrcSocket
+		ddpkt.SrcNet = myAddr.Proto.Network
+		ddpkt.SrcNode = myAddr.Proto.Node
+		ddpkt.SrcSocket = 2
+		ddpkt.Data = respRaw
+		outFrame, err := ethertalk.AppleTalk(myHWAddr, *ddpkt)
+		if err != nil {
+			return err
+		}
+		outFrame.Dst = srcHWAddr
+		outFrameRaw, err := ethertalk.Marshal(*outFrame)
+		if err != nil {
+			return err
+		}
+		return pcapHandle.WritePacketData(outFrameRaw)
 
-	// There must be 1!
-	tuple := nbpkt.Tuples[0]
+	case nbp.FunctionBrRq:
+		// There must be 1!
+		tuple := nbpkt.Tuples[0]
 
-	if tuple.Zone != cfg.EtherTalk.ZoneName {
-		// TODO: Translate it into a FwdReq and route it to the
-		// routers with the appropriate zone(s).
-		return errors.New("TODO: BrRq-FwdReq translation")
-	}
+		if tuple.Zone != cfg.EtherTalk.ZoneName {
+			// TODO: Translate it into a FwdReq and route it to the
+			// routers with the appropriate zone(s).
+			return errors.New("TODO: BrRq-FwdReq translation")
+		}
 
-	// If it's for the local zone, translate it to a LkUp and broadcast it back
-	// out the EtherTalk port.
-	// "Note: On an internet, nodes on extended networks performing lookups in
-	// their own zone must replace a zone name of asterisk (*) with their actual
-	// zone name before sending the packet to A-ROUTER. All nodes performing
-	// lookups in their own zone will receive LkUp packets from themselves
-	// (actually sent by a router). The node's NBP process should expect to
-	// receive these packets and must reply to them."
-	// TODO: use zone-specific multicast
-	nbpkt.Function = nbp.FunctionLkUp
-	nbpRaw, err := nbpkt.Marshal()
-	if err != nil {
-		return fmt.Errorf("couldn't marshal LkUp: %v", err)
-	}
+		// If it's for the local zone, translate it to a LkUp and broadcast it back
+		// out the EtherTalk port.
+		// "Note: On an internet, nodes on extended networks performing lookups in
+		// their own zone must replace a zone name of asterisk (*) with their actual
+		// zone name before sending the packet to A-ROUTER. All nodes performing
+		// lookups in their own zone will receive LkUp packets from themselves
+		// (actually sent by a router). The node's NBP process should expect to
+		// receive these packets and must reply to them."
+		// TODO: use zone-specific multicast
+		nbpkt.Function = nbp.FunctionLkUp
+		nbpRaw, err := nbpkt.Marshal()
+		if err != nil {
+			return fmt.Errorf("couldn't marshal LkUp: %v", err)
+		}
 
-	ddpkt.DstNode = 0xFF // Broadcast node address within the dest network
-	ddpkt.Data = nbpRaw
+		ddpkt.DstNode = 0xFF // Broadcast node address within the dest network
+		ddpkt.Data = nbpRaw
 
-	outFrame, err := ethertalk.AppleTalk(myHWAddr, *ddpkt)
-	if err != nil {
-		return err
+		outFrame, err := ethertalk.AppleTalk(myHWAddr, *ddpkt)
+		if err != nil {
+			return err
+		}
+		outFrameRaw, err := ethertalk.Marshal(*outFrame)
+		if err != nil {
+			return err
+		}
+		return pcapHandle.WritePacketData(outFrameRaw)
+
+	default:
+		return fmt.Errorf("TODO: handle function %v", nbpkt.Function)
 	}
-	outFrameRaw, err := ethertalk.Marshal(*outFrame)
-	if err != nil {
-		return err
-	}
-	return pcapHandle.WritePacketData(outFrameRaw)
 }
 
 func handleZIP(pcapHandle *pcap.Handle, srcHWAddr, myHWAddr ethernet.Addr, myAddr aarp.AddrPair, cfg *config, ddpkt *ddp.ExtPacket) error {