Remove ndp.go and add icmpv6.go

src/yggdrasil/icmpv6.go

@@ -0,0 +1,203 @@
+package yggdrasil
+
+// The NDP functions are needed when you are running with a
+// TAP adapter - as the operating system expects neighbor solicitations
+// for on-link traffic, this goroutine provides them
+
+import "golang.org/x/net/icmp"
+import "encoding/binary"
+import "unsafe" // TODO investigate if this can be done without resorting to unsafe
+
+type macAddress [6]byte
+type ipv6Address [16]byte
+
+const ETHER = 14
+const IPV6 = 40
+
+type icmpv6 struct {
+	tun        *tunDevice
+	peermac    macAddress
+	peerlladdr ipv6Address
+	mymac      macAddress
+	mylladdr   ipv6Address
+	recv       chan []byte
+}
+
+type etherHeader struct {
+	destination macAddress
+	source      macAddress
+	ethertype   [2]byte
+}
+
+type ipv6Header struct {
+	preamble    [4]byte
+	length      [2]byte
+	nextheader  byte
+	hoplimit    byte
+	source      ipv6Address
+	destination ipv6Address
+}
+
+type icmpv6Header struct {
+	messagetype byte
+	code        byte
+	checksum    uint16
+}
+
+type icmpv6PseudoHeader struct {
+	source      ipv6Address
+	destination ipv6Address
+	length      [4]byte
+	zero        [3]byte
+	nextheader  byte
+}
+
+type icmpv6Payload struct {
+	ether            etherHeader
+	ipv6             ipv6Header
+	icmpv6           icmpv6Header
+	flags            [4]byte
+	targetaddress    ipv6Address
+	optiontype       byte
+	optionlength     byte
+	linklayeraddress macAddress
+}
+
+type icmpv6Packet struct {
+	ipv6    ipv6Header
+	payload icmpv6Payload
+}
+
+type icmpv6Frame struct {
+	ether  etherHeader
+	packet icmpv6Packet
+}
+
+func (i *icmpv6) init(t *tunDevice) {
+	i.tun = t
+	i.recv = make(chan []byte)
+	copy(i.mymac[:], []byte{0x02, 0x00, 0x00, 0x00, 0x00, 0x02})
+	copy(i.mylladdr[:], []byte{
+		0xFE, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0xFE})
+	go i.listen()
+}
+
+func (i *icmpv6) listen() {
+	for {
+		datain := <-i.recv
+
+		if i.tun.iface.IsTAP() {
+			// TAP mode
+			dataout := make([]byte, ETHER+IPV6+32)
+			i.read_tap(datain, dataout)
+			i.tun.iface.Write(dataout)
+		} else {
+			// TUN mode
+			dataout := make([]byte, IPV6+32)
+			i.read_tun(datain, dataout)
+			i.tun.iface.Write(dataout)
+		}
+	}
+}
+
+func (i *icmpv6) read_tap(datain []byte, dataout []byte) {
+	// Set up
+	in := (*icmpv6Frame)(unsafe.Pointer(&datain[0]))
+	out := (*icmpv6Frame)(unsafe.Pointer(&dataout[0]))
+
+	// Store the peer MAC address
+	copy(i.peermac[:6], in.ether.source[:6])
+
+	// Ignore non-IPv6 frames
+	if binary.BigEndian.Uint16(in.ether.ethertype[:]) != uint16(0x86DD) {
+		return
+	}
+
+	// Populate the out ethernet headers
+	copy(out.ether.destination[:], in.ether.destination[:])
+	copy(out.ether.source[:], i.mymac[:])
+	binary.BigEndian.PutUint16(out.ether.ethertype[:], uint16(0x86DD))
+
+	// And for now just copy the rest of the packet we were sent
+	copy(dataout[ETHER:ETHER+IPV6], datain[ETHER:ETHER+IPV6])
+
+	// Then pass the IP packet onto the next function
+	i.read_tun(datain[ETHER:], dataout[ETHER:])
+}
+
+func (i *icmpv6) read_tun(datain []byte, dataout []byte) {
+	// Set up
+	in := (*icmpv6Packet)(unsafe.Pointer(&datain[0]))
+	out := (*icmpv6Packet)(unsafe.Pointer(&dataout[0]))
+
+	// Store the peer link-local address
+	copy(i.peerlladdr[:16], in.ipv6.source[:16])
+
+	// Ignore non-ICMPv6 packets
+	if in.ipv6.nextheader != uint8(0x3A) {
+		return
+	}
+
+	// What is the ICMPv6 message type?
+	switch in.payload.icmpv6.messagetype {
+	case uint8(135):
+		i.handle_ndp(&in.payload, &out.payload)
+		break
+	}
+
+	// Update the source and destination addresses in the IPv6 header
+	copy(out.ipv6.destination[:], in.ipv6.source[:])
+	copy(out.ipv6.source[:], i.mylladdr[:])
+	binary.BigEndian.PutUint16(out.ipv6.length[:], uint16(32))
+
+	// Copy the payload
+	copy(dataout[IPV6:], datain[IPV6:])
+
+	// Calculate the checksum
+	i.calculate_checksum(dataout)
+}
+
+func (i *icmpv6) calculate_checksum(dataout []byte) {
+	// Set up
+	out := (*icmpv6Packet)(unsafe.Pointer(&dataout[0]))
+
+	// Generate the pseudo-header for the checksum
+	ps := make([]byte, 44)
+	pseudo := (*icmpv6PseudoHeader)(unsafe.Pointer(&ps[0]))
+	copy(pseudo.destination[:], out.ipv6.destination[:])
+	copy(pseudo.source[:], out.ipv6.source[:])
+	binary.BigEndian.PutUint32(pseudo.length[:], uint32(binary.BigEndian.Uint16(out.ipv6.length[:])))
+	pseudo.nextheader = out.ipv6.nextheader
+
+	// Lazy-man's checksum using the icmp library
+	icmpv6, err := icmp.ParseMessage(0x3A, dataout[IPV6:])
+	if err != nil {
+		return
+	}
+
+	// And copy the payload
+	payload, err := icmpv6.Marshal(ps)
+	if err != nil {
+		return
+	}
+	copy(dataout[IPV6:], payload)
+}
+
+func (i *icmpv6) handle_ndp(in *icmpv6Payload, out *icmpv6Payload) {
+	// Ignore NDP requests for anything outside of fd00::/8
+	if in.targetaddress[0] != 0xFD {
+		return
+	}
+
+	// Update the ICMPv6 headers
+	out.icmpv6.messagetype = uint8(136)
+	out.icmpv6.code = uint8(0)
+
+	// Update the ICMPv6 payload
+	copy(out.targetaddress[:], in.targetaddress[:])
+	out.optiontype = uint8(2)
+	out.optionlength = uint8(1)
+	copy(out.linklayeraddress[:], i.mymac[:])
+	binary.BigEndian.PutUint32(out.flags[:], uint32(0x20000000))
+}

src/yggdrasil/ndp.go

@@ -1,165 +0,0 @@
-package yggdrasil
-
-// The NDP functions are needed when you are running with a
-// TAP adapter - as the operating system expects neighbor solicitations
-// for on-link traffic, this goroutine provides them
-
-import "golang.org/x/net/icmp"
-import "encoding/binary"
-import "unsafe" // TODO investigate if this can be done without resorting to unsafe
-
-type macAddress [6]byte
-type ipv6Address [16]byte
-
-const ETHER = 14
-const IPV6 = 40
-
-type ndp struct {
-	tun        *tunDevice
-	peermac    macAddress
-	peerlladdr ipv6Address
-	mymac      macAddress
-	mylladdr   ipv6Address
-	recv       chan []byte
-}
-
-type etherHeader struct {
-	destination macAddress
-	source      macAddress
-	ethertype   [2]byte
-}
-
-type ipv6Header struct {
-	preamble    [4]byte
-	length      [2]byte
-	nextheader  byte
-	hoplimit    byte
-	source      ipv6Address
-	destination ipv6Address
-}
-
-type icmpv6Header struct {
-	messagetype byte
-	code        byte
-	checksum    uint16
-}
-
-type icmpv6PseudoHeader struct {
-	source      ipv6Address
-	destination ipv6Address
-	length      [4]byte
-	zero        [3]byte
-	nextheader  byte
-}
-
-type icmpv6Packet struct {
-	ether            etherHeader
-	ipv6             ipv6Header
-	icmpv6           icmpv6Header
-	flags            [4]byte
-	targetaddress    ipv6Address
-	optiontype       byte
-	optionlength     byte
-	linklayeraddress macAddress
-}
-
-func (n *ndp) init(t *tunDevice) {
-	n.tun = t
-	n.recv = make(chan []byte)
-	copy(n.mymac[:], []byte{0x02, 0x00, 0x00, 0x00, 0x00, 0x02})
-	copy(n.mylladdr[:], []byte{
-		0xFE, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0xFE})
-	go n.listen()
-}
-
-func (n *ndp) listen() {
-	for {
-		// Receive from the channel and check if we're using TAP instead
-		// of TUN mode - NDP is only relevant for TAP
-		datain := <-n.recv
-		if !n.tun.iface.IsTAP() {
-			continue
-		}
-
-		// Create our return frame buffer and also the unsafe pointers to
-		// map them to the structs
-		dataout := make([]byte, ETHER+IPV6+32)
-		in := (*icmpv6Packet)(unsafe.Pointer(&datain[0]))
-		out := (*icmpv6Packet)(unsafe.Pointer(&dataout[0]))
-
-		// Store peer MAC address and link-local IP address -
-		// these will be used later by tun.go
-		copy(n.peermac[:6], in.ether.source[:6])
-		copy(n.peerlladdr[:16], in.ipv6.source[:16])
-
-		// Ignore non-IPv6 packets
-		if binary.BigEndian.Uint16(in.ether.ethertype[:]) != uint16(0x86DD) {
-			continue
-		}
-
-		// Ignore non-ICMPv6 packets
-		if in.ipv6.nextheader != uint8(0x3A) {
-			continue
-		}
-
-		// Ignore non-NDP Solicitation packets
-		if in.icmpv6.messagetype != uint8(135) {
-			continue
-		}
-
-		// Ignore NDP requests for anything outside of fd00::/8
-		if in.targetaddress[0] != 0xFD {
-			continue
-		}
-
-		// Populate the out ethernet headers
-		copy(out.ether.destination[:], in.ether.destination[:])
-		copy(out.ether.source[:], n.mymac[:])
-		binary.BigEndian.PutUint16(out.ether.ethertype[:], uint16(0x86DD))
-
-		// And for now just copy the rest of the packet we were sent
-		copy(dataout[ETHER:ETHER+IPV6], datain[ETHER:ETHER+IPV6])
-
-		// Update the source and destination addresses in the IPv6 header
-		copy(out.ipv6.destination[:], in.ipv6.source[:])
-		copy(out.ipv6.source[:], n.mylladdr[:])
-		binary.BigEndian.PutUint16(out.ipv6.length[:], uint16(32))
-
-		// Copy the payload
-		copy(dataout[ETHER+IPV6:], datain[ETHER+IPV6:])
-
-		// Update the ICMPv6 headers
-		out.icmpv6.messagetype = uint8(136)
-		out.icmpv6.code = uint8(0)
-
-		// Update the ICMPv6 payload
-		copy(out.targetaddress[:], in.targetaddress[:])
-		out.optiontype = uint8(2)
-		out.optionlength = uint8(1)
-		copy(out.linklayeraddress[:], n.mymac[:])
-		binary.BigEndian.PutUint32(out.flags[:], uint32(0x20000000))
-
-		// Generate the pseudo-header for the checksum
-		ps := make([]byte, 44)
-		pseudo := (*icmpv6PseudoHeader)(unsafe.Pointer(&ps[0]))
-		copy(pseudo.destination[:], out.ipv6.destination[:])
-		copy(pseudo.source[:], out.ipv6.source[:])
-		binary.BigEndian.PutUint32(pseudo.length[:], uint32(binary.BigEndian.Uint16(out.ipv6.length[:])))
-		pseudo.nextheader = out.ipv6.nextheader
-
-		// Lazy-man's checksum using the icmp library
-		icmpv6, err := icmp.ParseMessage(0x3A, dataout[ETHER+IPV6:])
-		if err != nil {
-			continue
-		}
-		payload, err := icmpv6.Marshal(ps)
-		if err != nil {
-			continue
-		}
-		copy(dataout[ETHER+IPV6:], payload)
-
-		// Send the frame back to the TAP adapter
-		n.tun.iface.Write(dataout)
-	}
-}

src/yggdrasil/tun.go

@@ -18,7 +18,7 @@ type tunInterface interface {
 
 type tunDevice struct {
 	core   *Core
-	ndp   ndp
+	icmpv6 icmpv6
 	send   chan<- []byte
 	recv   <-chan []byte
 	mtu    int
@@ -27,7 +27,7 @@ type tunDevice struct {
 
 func (tun *tunDevice) init(core *Core) {
 	tun.core = core
-	tun.ndp.init(tun)
+	tun.icmpv6.init(tun)
 }
 
 func (tun *tunDevice) write() error {
@@ -36,8 +36,8 @@ func (tun *tunDevice) write() error {
 		if tun.iface.IsTAP() {
 			var frame ethernet.Frame
 			frame.Prepare(
-				tun.ndp.peermac[:6], // Destination MAC address
+				tun.icmpv6.peermac[:6], // Destination MAC address
-				tun.ndp.mymac[:6],   // Source MAC address
+				tun.icmpv6.mymac[:6],   // Source MAC address
 				ethernet.NotTagged,     // VLAN tagging
 				ethernet.IPv6,          // Ethertype
 				len(data))              // Payload length
@@ -68,9 +68,6 @@ func (tun *tunDevice) read() error {
 		o := 0
 		if tun.iface.IsTAP() {
 			o = ETHER_HEADER_LENGTH
-			b := make([]byte, n)
-			copy(b, buf)
-			tun.ndp.recv <- b
 		}
 		if buf[o]&0xf0 != 0x60 ||
 			n != 256*int(buf[o+4])+int(buf[o+5])+IPv6_HEADER_LENGTH+o {
@@ -78,6 +75,12 @@ func (tun *tunDevice) read() error {
 			//panic("Should not happen in testing")
 			continue
 		}
+		if buf[o+6] == 58 {
+			// Found an ICMPv6 packet
+			b := make([]byte, n)
+			copy(b, buf)
+			tun.icmpv6.recv <- b
+		}
 		packet := append(util_getBytes(), buf[o:n]...)
 		tun.send <- packet
 	}