Add initial crypto-key routing handlers

src/yggdrasil/ckr.go

@@ -0,0 +1,104 @@
+package yggdrasil
+
+import (
+	"encoding/hex"
+	"errors"
+	"net"
+	"sort"
+)
+
+// This module implements crypto-key routing, similar to Wireguard, where we
+// allow traffic for non-Yggdrasil ranges to be routed over Yggdrasil.
+
+type cryptokey struct {
+	core       *Core
+	enabled    bool
+	ipv4routes []cryptokey_route
+	ipv6routes []cryptokey_route
+}
+
+type cryptokey_route struct {
+	subnet      net.IPNet
+	destination []byte
+}
+
+func (c *cryptokey) init(core *Core) {
+	c.core = core
+	c.ipv4routes = make([]cryptokey_route, 0)
+	c.ipv6routes = make([]cryptokey_route, 0)
+}
+
+func (c *cryptokey) isEnabled() bool {
+	return c.enabled
+}
+
+func (c *cryptokey) addRoute(cidr string, dest string) error {
+	// Is the CIDR we've been given valid?
+	_, ipnet, err := net.ParseCIDR(cidr)
+	if err != nil {
+		return err
+	}
+
+	// Get the prefix length and size
+	prefixlen, prefixsize := ipnet.Mask.Size()
+
+	// Check if the prefix is IPv4 or IPv6
+	if prefixsize == net.IPv6len*8 {
+		// IPv6
+		for _, route := range c.ipv6routes {
+			// Do we already have a route for this subnet?
+			routeprefixlen, _ := route.subnet.Mask.Size()
+			if route.subnet.IP.Equal(ipnet.IP) && routeprefixlen == prefixlen {
+				return errors.New("IPv6 route already exists")
+			}
+		}
+		// Decode the public key
+		if boxPubKey, err := hex.DecodeString(dest); err != nil {
+			return err
+		} else {
+			// Add the new crypto-key route
+			c.ipv6routes = append(c.ipv6routes, cryptokey_route{
+				subnet:      *ipnet,
+				destination: boxPubKey,
+			})
+			// Sort so most specific routes are first
+			sort.Slice(c.ipv6routes, func(i, j int) bool {
+				im, _ := c.ipv6routes[i].subnet.Mask.Size()
+				jm, _ := c.ipv6routes[j].subnet.Mask.Size()
+				return im > jm
+			})
+			return nil
+		}
+	} else if prefixsize == net.IPv4len*8 {
+		// IPv4
+		return errors.New("IPv4 not supported at this time")
+	}
+	return errors.New("Unspecified error")
+}
+
+func (c *cryptokey) getPublicKeyForAddress(addr string) (boxPubKey, error) {
+	ipaddr := net.ParseIP(addr)
+
+	if ipaddr.To4() == nil {
+		// IPv6
+		for _, route := range c.ipv6routes {
+			if route.subnet.Contains(ipaddr) {
+				var box boxPubKey
+				copy(box[:boxPubKeyLen], route.destination)
+				return box, nil
+			}
+		}
+	} else {
+		// IPv4
+		return boxPubKey{}, errors.New("IPv4 not supported at this time")
+		/*
+			    for _, route := range c.ipv4routes {
+						if route.subnet.Contains(ipaddr) {
+							return route.destination, nil
+						}
+					}
+		*/
+	}
+
+	return boxPubKey{}, errors.New("No route")
+}

src/yggdrasil/config/config.go

@@ -17,6 +17,7 @@ type NodeConfig struct {
 	IfTAPMode                   bool                `comment:"Set local network interface to TAP mode rather than TUN mode if\nsupported by your platform - option will be ignored if not."`
 	IfMTU                       int                 `comment:"Maximux Transmission Unit (MTU) size for your local TUN/TAP interface.\nDefault is the largest supported size for your platform. The lowest\npossible value is 1280."`
 	SessionFirewall             SessionFirewall     `comment:"The session firewall controls who can send/receive network traffic\nto/from. This is useful if you want to protect this node without\nresorting to using a real firewall. This does not affect traffic\nbeing routed via this node to somewhere else. Rules are prioritised as\nfollows: blacklist, whitelist, always allow outgoing, direct, remote."`
+	TunnelRouting               TunnelRouting       `comment:"Allow tunneling non-Yggdrasil traffic over Yggdrasil."`
 	//Net                         NetConfig `comment:"Extended options for connecting to peers over other networks."`
 }
 
@@ -26,6 +27,7 @@ type NetConfig struct {
 	I2P I2PConfig `comment:"Experimental options for configuring peerings over I2P."`
 }
 
+// SessionFirewall controls the session firewall configuration
 type SessionFirewall struct {
 	Enable                        bool     `comment:"Enable or disable the session firewall. If disabled, network traffic\nfrom any node will be allowed. If enabled, the below rules apply."`
 	AllowFromDirect               bool     `comment:"Allow network traffic from directly connected peers."`
@@ -34,3 +36,9 @@ type SessionFirewall struct {
 	WhitelistEncryptionPublicKeys []string `comment:"List of public keys from which network traffic is always accepted,\nregardless of AllowFromDirect or AllowFromRemote."`
 	BlacklistEncryptionPublicKeys []string `comment:"List of public keys from which network traffic is always rejected,\nregardless of the whitelist, AllowFromDirect or AllowFromRemote."`
 }
+
+// TunnelRouting contains the crypto-key routing tables for tunneling
+type TunnelRouting struct {
+	Enable     bool              `comment:"Enable or disable tunneling."`
+	IPv6Routes map[string]string `comment:"IPv6 subnets, mapped to the public keys to which they should be routed."`
+}

src/yggdrasil/core.go

@@ -121,6 +121,14 @@ func (c *Core) Start(nc *config.NodeConfig, log *log.Logger) error {
 		return err
 	}
 
+	if nc.TunnelRouting.Enable {
+		for ipv6, pubkey := range nc.TunnelRouting.IPv6Routes {
+			if err := c.router.cryptokey.addRoute(ipv6, pubkey); err != nil {
+				panic(err)
+			}
+		}
+	}
+
 	if err := c.admin.start(); err != nil {
 		c.log.Println("Failed to start admin socket")
 		return err

src/yggdrasil/router.go

@@ -40,6 +40,7 @@ type router struct {
 	send      <-chan []byte // place where the tun puts outgoing packets
 	reset     chan struct{} // signal that coords changed (re-init sessions/dht)
 	admin     chan func()   // pass a lambda for the admin socket to query stuff
+	cryptokey cryptokey
 }
 
 // Initializes the router struct, which includes setting up channels to/from the tun/tap.
@@ -67,6 +68,7 @@ func (r *router) init(core *Core) {
 	r.core.tun.send = send
 	r.reset = make(chan struct{}, 1)
 	r.admin = make(chan func())
+	r.cryptokey.init(r.core)
 	// go r.mainLoop()
 }