add dhcp failing test

internet/definitions.go

@@ -104,6 +104,28 @@ func getNode(nodes []node, port uint16, protocol uint16) (node *node) {
 	return nil
 }
 
+func getEncapsulateNode(nodes *[]node, carrierData []byte, frameOffset int) (nodeIdx int, written int, err error) {
+	destroyed := false
+	for i := range *nodes {
+		node := &(*nodes)[i]
+		if checkNode(node) {
+			destroyed = true
+			node.destroy()
+			continue
+		}
+		written, err = node.encapsulate(carrierData, frameOffset)
+		if written > 0 {
+			return i, written, err
+		} else if err != nil {
+
+		}
+	}
+	if destroyed {
+		*nodes = nodesCompact(*nodes)
+	}
+	return -1, 0, nil
+}
+
 // destroy removes all references to underlying StackNode. Allows garbage collection of node if possible.
 func (n *node) destroy() {
 	*n = node{}
@@ -116,5 +138,17 @@ func getNodeByProto(nodes []node, protocol uint16) int {
 			return i
 		}
 	}
+
 	return -1
 }
+
+func nodesCompact(nodes []node) []node {
+	nilOff := 0
+	for i := 0; i < len(nodes); i++ {
+		if !checkNode(&nodes[i]) {
+			nodes[nilOff] = nodes[i]
+			nilOff++
+		}
+	}
+	return nodes[:nilOff]
+}

internet/node-tcplistener.go

@@ -123,7 +123,7 @@ func (listener *NodeTCPListener) Demux(carrierData []byte, tcpFrameOffset int) e
 	if err != nil {
 		return err
 	}
-	addr, _, err := internal.GetIPSourceAddr(carrierData)
+	addr, _, _, err := internal.GetIPSourceAddr(carrierData)
 	if err != nil {
 		return err
 	}

internet/stack-ip.go

@@ -18,6 +18,7 @@ var _ StackNode = (*StackIP)(nil)
 
 type StackIP struct {
 	connID    uint64
+	ipID      uint16
 	ip        [4]byte
 	validator lneto.Validator
 	handlers  []node
@@ -136,24 +137,31 @@ func (sb *StackIP) Encapsulate(carrierData []byte, frameOffset int) (int, error)
 	ifrm, _ := ipv4.NewFrame(frame)
 	const ihl = 5
 	const headerlen = ihl * 4
+	const dontFrag = 0x4000
 	ifrm.SetVersionAndIHL(4, ihl)
 	ifrm.SetToS(0)
-	ifrm.SetID(0)
+	seed := sb.ipID + uint16(sb.connID)
+	id := internal.Prand16(seed)
+	ifrm.SetID(id)
+	ifrm.SetFlags(dontFrag)
 	*ifrm.SourceAddr() = sb.ip
+	sb.ipID = id
 	for i := range sb.handlers {
 		h := &sb.handlers[i]
 		proto := lneto.IPProto(h.proto)
 		n, err := h.encapsulate(frame[:], headerlen)
 		if err != nil {
+			if handleNodeError(&sb.handlers, i, err) {
+				println("NODE REMOVED", proto.String(), h.port)
+				h.destroy()
+			}
 			sb.error("StackIP:handle", slog.String("proto", proto.String()), slog.String("err", err.Error()))
 			continue
 		} else if n == 0 {
 			continue
 		}
-		const dontFrag = 0x4000
 		totalLen := n + headerlen
 		ifrm.SetTotalLength(uint16(totalLen))
-		ifrm.SetFlags(dontFrag)
 		ifrm.SetTTL(64)
 		ifrm.SetProtocol(proto)
 		ifrm.SetCRC(ifrm.CalculateHeaderCRC())
@@ -168,8 +176,13 @@ func (sb *StackIP) Encapsulate(carrierData []byte, frameOffset int) (int, error)
 		case lneto.IPProtoUDP:
 			ifrm.CRCWriteUDPPseudo(&crc)
 			ufrm, _ := udp.NewFrame(ifrm.Payload())
+			ufrm.SetLength(uint16(n))
 			ufrm.CRCWriteIPv4(&crc)
 			ufrm.SetCRC(crc.Sum16())
+			if n != int(ufrm.Length()) {
+				sb.error("StackIP:encaps", slog.Int("n", n), slog.Int("un", int(ufrm.Length())))
+				return 0, errors.New("invalid UDP length")
+			}
 		}
 		return totalLen, nil
 	}

internet/stack-udpport.go

@@ -47,7 +47,7 @@ func (sudp *StackUDPPort) Demux(carrierData []byte, frameOffset int) error {
 	if sudp.rmport != 0 && src != sudp.rmport {
 		return nil // Not from our target remote port.
 	}
-	err = sudp.h.demux(ufrm.Payload(), 8)
+	err = sudp.h.demux(carrierData, frameOffset+8)
 	if err != nil {
 		if checkNodeErr(&sudp.h, err) {
 			sudp.h.destroy()
@@ -68,11 +68,14 @@ func (sudp *StackUDPPort) Encapsulate(carrierData []byte, frameOffset int) (int,
 	}
 	ufrm.SetSourcePort(sudp.h.port)
 	ufrm.SetDestinationPort(sudp.rmport)
-	n, err := sudp.h.encapsulate(carrierData[frameOffset:], 8)
-	if err != nil {
-		slog.Error("stackudp:demux", slog.String("err", err.Error()))
+	n, err := sudp.h.encapsulate(carrierData, frameOffset+8)
+	if n == 0 {
+		if err != nil {
+			slog.Error("stackudp:demux", slog.String("err", err.Error()))
+		}
+		return 0, err
 	}
-	ufrm.SetLength(8 + uint16(n))
-	// UDP CRC left to IP layer.
-	return n, err
+	// UDP CRC and length left to IP layer.
+	length := 8 + n
+	return length, err
 }