Beginning work on TUN interface

And outbound routing

I am not entirely convinced the use of net.IP is a good idea,
since the internal representation of net.IP is a byte slice
and all constructor functions in "net" return 16 byte slices
(padded for IPv4), while the use in this project uses 4 byte slices.
Which may be confusing.

src/routing.go

@@ -1,13 +1,12 @@
 package main
 
 import (
+	"errors"
+	"fmt"
+	"net"
 	"sync"
 )
 
-/* Thread-safe high level functions for cryptkey routing.
- *
- */
-
 type RoutingTable struct {
 	IPv4  *Trie
 	IPv6  *Trie
@@ -20,3 +19,51 @@ func (table *RoutingTable) RemovePeer(peer *Peer) {
 	table.IPv4 = table.IPv4.RemovePeer(peer)
 	table.IPv6 = table.IPv6.RemovePeer(peer)
 }
+
+func (table *RoutingTable) Insert(ip net.IP, cidr uint, peer *Peer) {
+	table.mutex.Lock()
+	defer table.mutex.Unlock()
+
+	switch len(ip) {
+	case net.IPv6len:
+		table.IPv6 = table.IPv6.Insert(ip, cidr, peer)
+	case net.IPv4len:
+		table.IPv4 = table.IPv4.Insert(ip, cidr, peer)
+	default:
+		panic(errors.New("Inserting unknown address type"))
+	}
+}
+
+func (table *RoutingTable) LookupIPv4(address []byte) *Peer {
+	table.mutex.RLock()
+	defer table.mutex.RUnlock()
+	return table.IPv4.Lookup(address)
+}
+
+func (table *RoutingTable) LookupIPv6(address []byte) *Peer {
+	table.mutex.RLock()
+	defer table.mutex.RUnlock()
+	return table.IPv6.Lookup(address)
+}
+
+func OutgoingRoutingWorker(device *Device, queue chan []byte) {
+	for {
+		packet := <-queue
+		switch packet[0] >> 4 {
+
+		case IPv4version:
+			dst := packet[IPv4offsetDst : IPv4offsetDst+net.IPv4len]
+			peer := device.routingTable.LookupIPv4(dst)
+			fmt.Println("IPv4", peer)
+
+		case IPv6version:
+			dst := packet[IPv6offsetDst : IPv6offsetDst+net.IPv6len]
+			peer := device.routingTable.LookupIPv6(dst)
+			fmt.Println("IPv6", peer)
+
+		default:
+			// todo: log
+			fmt.Println("Unknown IP version")
+		}
+	}
+}