Fix TAP mode

src/tuntap/ckr.go

@@ -48,8 +48,11 @@ func (c *cryptokey) init(tun *TunAdapter) {
 		}
 	}()
 
+	c.tun.log.Debugln("Configuring CKR...")
 	if err := c.configure(); err != nil {
 		c.tun.log.Errorln("CKR configuration failed:", err)
+	} else {
+		c.tun.log.Debugln("CKR configured")
 	}
 }
 

src/tuntap/icmpv6.go

@@ -13,6 +13,7 @@ import (
 	"encoding/binary"
 	"errors"
 	"net"
+	"sync"
 	"time"
 
 	"golang.org/x/net/icmp"
@@ -21,19 +22,18 @@ import (
 	"github.com/yggdrasil-network/yggdrasil-go/src/address"
 )
 
-type macAddress [6]byte
-
 const len_ETHER = 14
 
 type ICMPv6 struct {
 	tun           *TunAdapter
 	mylladdr      net.IP
-	mymac    macAddress
+	mymac         net.HardwareAddr
 	peermacs      map[address.Address]neighbor
+	peermacsmutex sync.RWMutex
 }
 
 type neighbor struct {
-	mac               macAddress
+	mac               net.HardwareAddr
 	learned           bool
 	lastadvertisement time.Time
 	lastsolicitation  time.Time
@@ -61,10 +61,12 @@ func ipv6Header_Marshal(h *ipv6.Header) ([]byte, error) {
 // addresses.
 func (i *ICMPv6) Init(t *TunAdapter) {
 	i.tun = t
+	i.peermacsmutex.Lock()
 	i.peermacs = make(map[address.Address]neighbor)
+	i.peermacsmutex.Unlock()
 
 	// Our MAC address and link-local address
-	i.mymac = macAddress{
+	i.mymac = net.HardwareAddr{
 		0x02, 0x00, 0x00, 0x00, 0x00, 0x02}
 	i.mylladdr = net.IP{
 		0xFE, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
@@ -181,16 +183,30 @@ func (i *ICMPv6) UnmarshalPacket(datain []byte, datamac *[]byte) ([]byte, error)
 		if datamac != nil {
 			var addr address.Address
 			var target address.Address
-			var mac macAddress
+			mac := net.HardwareAddr{0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
 			copy(addr[:], ipv6Header.Src[:])
 			copy(target[:], datain[48:64])
 			copy(mac[:], (*datamac)[:])
-			// fmt.Printf("Learning peer MAC %x for %x\n", mac, target)
+			i.peermacsmutex.Lock()
 			neighbor := i.peermacs[target]
 			neighbor.mac = mac
 			neighbor.learned = true
 			neighbor.lastadvertisement = time.Now()
 			i.peermacs[target] = neighbor
+			i.peermacsmutex.Unlock()
+			i.tun.log.Debugln("Learned peer MAC", mac.String(), "for", net.IP(target[:]).String())
+			/*
+				i.tun.log.Debugln("Peer MAC table:")
+				i.peermacsmutex.RLock()
+				for t, n := range i.peermacs {
+					if n.learned {
+						i.tun.log.Debugln("- Target", net.IP(t[:]).String(), "has MAC", n.mac.String())
+					} else {
+						i.tun.log.Debugln("- Target", net.IP(t[:]).String(), "is not learned yet")
+					}
+				}
+				i.peermacsmutex.RUnlock()
+			*/
 		}
 		return nil, errors.New("No response needed")
 	}
@@ -201,7 +217,7 @@ func (i *ICMPv6) UnmarshalPacket(datain []byte, datamac *[]byte) ([]byte, error)
 // Creates an ICMPv6 packet based on the given icmp.MessageBody and other
 // parameters, complete with ethernet and IP headers, which can be written
 // directly to a TAP adapter.
-func (i *ICMPv6) CreateICMPv6L2(dstmac macAddress, dst net.IP, src net.IP, mtype ipv6.ICMPType, mcode int, mbody icmp.MessageBody) ([]byte, error) {
+func (i *ICMPv6) CreateICMPv6L2(dstmac net.HardwareAddr, dst net.IP, src net.IP, mtype ipv6.ICMPType, mcode int, mbody icmp.MessageBody) ([]byte, error) {
 	// Pass through to CreateICMPv6
 	ipv6packet, err := CreateICMPv6(dst, src, mtype, mcode, mbody)
 	if err != nil {
@@ -264,13 +280,46 @@ func CreateICMPv6(dst net.IP, src net.IP, mtype ipv6.ICMPType, mcode int, mbody
 	return responsePacket, nil
 }
 
-func (i *ICMPv6) CreateNDPL2(dst address.Address) ([]byte, error) {
+func (i *ICMPv6) Solicit(addr address.Address) {
+	retries := 5
+	for retries > 0 {
+		retries--
+		i.peermacsmutex.RLock()
+		if n, ok := i.peermacs[addr]; ok && n.learned {
+			i.tun.log.Debugln("MAC learned for", net.IP(addr[:]).String())
+			i.peermacsmutex.RUnlock()
+			return
+		}
+		i.peermacsmutex.RUnlock()
+		i.tun.log.Debugln("Sending neighbor solicitation for", net.IP(addr[:]).String())
+		i.peermacsmutex.Lock()
+		if n, ok := i.peermacs[addr]; !ok {
+			i.peermacs[addr] = neighbor{
+				lastsolicitation: time.Now(),
+			}
+		} else {
+			n.lastsolicitation = time.Now()
+		}
+		i.peermacsmutex.Unlock()
+		request, err := i.createNDPL2(addr)
+		if err != nil {
+			panic(err)
+		}
+		if _, err := i.tun.iface.Write(request); err != nil {
+			panic(err)
+		}
+		i.tun.log.Debugln("Sent neighbor solicitation for", net.IP(addr[:]).String())
+		time.Sleep(time.Second)
+	}
+}
+
+func (i *ICMPv6) createNDPL2(dst address.Address) ([]byte, error) {
 	// Create the ND payload
 	var payload [28]byte
-	copy(payload[:4], []byte{0x00, 0x00, 0x00, 0x00})
-	copy(payload[4:20], dst[:])
-	copy(payload[20:22], []byte{0x01, 0x01})
-	copy(payload[22:28], i.mymac[:6])
+	copy(payload[:4], []byte{0x00, 0x00, 0x00, 0x00}) // Flags
+	copy(payload[4:20], dst[:])                       // Destination
+	copy(payload[20:22], []byte{0x01, 0x01})          // Type & length
+	copy(payload[22:28], i.mymac[:6])                 // Link layer address
 
 	// Create the ICMPv6 solicited-node address
 	var dstaddr address.Address
@@ -281,7 +330,7 @@ func (i *ICMPv6) CreateNDPL2(dst address.Address) ([]byte, error) {
 	copy(dstaddr[13:], dst[13:16])
 
 	// Create the multicast MAC
-	var dstmac macAddress
+	dstmac := net.HardwareAddr{0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
 	copy(dstmac[:2], []byte{0x33, 0x33})
 	copy(dstmac[2:6], dstaddr[12:16])
 
@@ -293,9 +342,6 @@ func (i *ICMPv6) CreateNDPL2(dst address.Address) ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	neighbor := i.peermacs[dstaddr]
-	neighbor.lastsolicitation = time.Now()
-	i.peermacs[dstaddr] = neighbor
 
 	return requestPacket, nil
 }
@@ -319,10 +365,10 @@ func (i *ICMPv6) HandleNDP(in []byte) ([]byte, error) {
 
 	// Create our NDP message body response
 	body := make([]byte, 28)
-	binary.BigEndian.PutUint32(body[:4], uint32(0x20000000))
+	binary.BigEndian.PutUint32(body[:4], uint32(0x40000000)) // Flags
 	copy(body[4:20], in[8:24])                               // Target address
-	body[20] = uint8(2)
-	body[21] = uint8(1)
+	body[20] = uint8(2)                                      // Type: Target link-layer address
+	body[21] = uint8(1)                                      // Length: 1x address (8 bytes)
 	copy(body[22:28], i.mymac[:6])
 
 	// Send it back

src/tuntap/iface.go

@@ -3,6 +3,7 @@ package tuntap
 import (
 	"bytes"
 	"errors"
+	"net"
 	"time"
 
 	"github.com/songgao/packets/ethernet"
@@ -43,19 +44,10 @@ func (tun *TunAdapter) writer() error {
 				neigh, known := tun.icmpv6.peermacs[dstAddr]
 				known = known && (time.Since(neigh.lastsolicitation).Seconds() < 30)
 				if !known {
-					request, err := tun.icmpv6.CreateNDPL2(dstAddr)
-					if err != nil {
-						panic(err)
-					}
-					if _, err := tun.iface.Write(request); err != nil {
-						panic(err)
-					}
-					tun.icmpv6.peermacs[dstAddr] = neighbor{
-						lastsolicitation: time.Now(),
+					tun.icmpv6.Solicit(dstAddr)
 				}
 			}
-			}
-			var peermac macAddress
+			peermac := net.HardwareAddr{0x00, 0x00, 0x00, 0x00, 0x00, 0x00}
 			var peerknown bool
 			if b[0]&0xf0 == 0x40 {
 				dstAddr = tun.addr
@@ -65,14 +57,19 @@ func (tun *TunAdapter) writer() error {
 				}
 			}
 			if neighbor, ok := tun.icmpv6.peermacs[dstAddr]; ok && neighbor.learned {
+				// If we've learned the MAC of a 300::/7 address, for example, or a CKR
+				// address, use the MAC address of that
 				peermac = neighbor.mac
 				peerknown = true
 			} else if neighbor, ok := tun.icmpv6.peermacs[tun.addr]; ok && neighbor.learned {
+				// Otherwise send directly to the MAC address of the host if that's
+				// known instead
 				peermac = neighbor.mac
 				peerknown = true
-				sendndp(dstAddr)
 			} else {
+				// Nothing has been discovered, try to discover the destination
 				sendndp(tun.addr)
+
 			}
 			if peerknown {
 				var proto ethernet.Ethertype
@@ -92,6 +89,8 @@ func (tun *TunAdapter) writer() error {
 				copy(frame[tun_ETHER_HEADER_LENGTH:], b[:n])
 				n += tun_ETHER_HEADER_LENGTH
 				w, err = tun.iface.Write(frame[:n])
+			} else {
+				tun.log.Errorln("TUN/TAP iface write error: no peer MAC known for", net.IP(dstAddr[:]).String(), "- dropping packet")
 			}
 		} else {
 			w, err = tun.iface.Write(b[:n])
@@ -184,7 +183,7 @@ func (tun *TunAdapter) reader() error {
 			// Unknown address length or protocol, so drop the packet and ignore it
 			continue
 		}
-		if !tun.ckr.isValidSource(srcAddr, addrlen) {
+		if tun.ckr.isEnabled() && !tun.ckr.isValidSource(srcAddr, addrlen) {
 			// The packet had a source address that doesn't belong to us or our
 			// configured crypto-key routing source subnets
 			continue

src/tuntap/tun.go

@@ -14,7 +14,6 @@ import (
 	"fmt"
 	"net"
 	"sync"
-	"time"
 
 	"github.com/gologme/log"
 	"github.com/yggdrasil-network/water"
@@ -152,21 +151,6 @@ func (tun *TunAdapter) Start() error {
 	tun.send = make(chan []byte, 32) // TODO: is this a sensible value?
 	tun.reconfigure = make(chan chan error)
 	tun.mutex.Unlock()
-	if iftapmode {
-		go func() {
-			for {
-				if _, ok := tun.icmpv6.peermacs[tun.addr]; ok {
-					break
-				}
-				request, err := tun.icmpv6.CreateNDPL2(tun.addr)
-				if err != nil {
-					panic(err)
-				}
-				tun.send <- request
-				time.Sleep(time.Second)
-			}
-		}()
-	}
 	go func() {
 		for {
 			e := <-tun.reconfigure
@@ -177,6 +161,9 @@ func (tun *TunAdapter) Start() error {
 	go tun.reader()
 	go tun.writer()
 	tun.icmpv6.Init(tun)
+	if iftapmode {
+		go tun.icmpv6.Solicit(tun.addr)
+	}
 	tun.ckr.init(tun)
 	return nil
 }