Link cost-aware routing

cmd/yggdrasilctl/main.go

@@ -174,7 +174,7 @@ func run() int {
 		if err := json.Unmarshal(recv.Response, &resp); err != nil {
 			panic(err)
 		}
-		table.SetHeader([]string{"URI", "State", "Dir", "IP Address", "Uptime", "RTT", "RX", "TX", "Pr", "Last Error"})
+		table.SetHeader([]string{"URI", "State", "Dir", "IP Address", "Uptime", "RTT", "RX", "TX", "Pr", "Cost", "Last Error"})
 		for _, peer := range resp.Peers {
 			state, lasterr, dir, rtt := "Up", "-", "Out", "-"
 			if !peer.Up {
@@ -200,6 +200,7 @@ func run() int {
 				peer.RXBytes.String(),
 				peer.TXBytes.String(),
 				fmt.Sprintf("%d", peer.Priority),
+				fmt.Sprintf("%d", peer.Cost),
 				lasterr,
 			})
 		}

src/admin/getpeers.go

@@ -24,6 +24,7 @@ type PeerEntry struct {
 	PublicKey     string        `json:"key"`
 	Port          uint64        `json:"port"`
 	Priority      uint64        `json:"priority"`
+	Cost          uint64        `json:"cost"`
 	RXBytes       DataUnit      `json:"bytes_recvd,omitempty"`
 	TXBytes       DataUnit      `json:"bytes_sent,omitempty"`
 	Uptime        float64       `json:"uptime,omitempty"`
@@ -41,6 +42,7 @@ func (a *AdminSocket) getPeersHandler(_ *GetPeersRequest, res *GetPeersResponse)
 			Up:       p.Up,
 			Inbound:  p.Inbound,
 			Priority: uint64(p.Priority), // can't be uint8 thanks to gobind
+			Cost:     uint64(p.Cost),     // can't be uint8 thanks to gobind
 			URI:      p.URI,
 			RXBytes:  DataUnit(p.RXBytes),
 			TXBytes:  DataUnit(p.TXBytes),

src/core/api.go

@@ -30,6 +30,7 @@ type PeerInfo struct {
 	Coords        []uint64
 	Port          uint64
 	Priority      uint8
+	Cost          uint8
 	RXBytes       uint64
 	TXBytes       uint64
 	Uptime        time.Duration
@@ -94,6 +95,7 @@ func (c *Core) GetPeers() []PeerInfo {
 				peerinfo.Port = p.Port
 				peerinfo.Priority = p.Priority
 				peerinfo.Latency = p.Latency
+				peerinfo.Cost = p.Cost
 			}
 			peers = append(peers, peerinfo)
 		}

src/core/link.go

@@ -70,6 +70,7 @@ type link struct {
 type linkOptions struct {
 	pinnedEd25519Keys map[keyArray]struct{}
 	priority          uint8
+	cost              uint8
 	tlsSNI            string
 	password          []byte
 	maxBackoff        time.Duration
@@ -139,6 +140,7 @@ func (e linkError) Error() string { return string(e) }
 const ErrLinkAlreadyConfigured = linkError("peer is already configured")
 const ErrLinkNotConfigured = linkError("peer is not configured")
 const ErrLinkPriorityInvalid = linkError("priority value is invalid")
+const ErrLinkCostInvalid = linkError("cost value is invalid")
 const ErrLinkPinnedKeyInvalid = linkError("pinned public key is invalid")
 const ErrLinkPasswordInvalid = linkError("password is invalid")
 const ErrLinkUnrecognisedSchema = linkError("link schema unknown")
@@ -181,6 +183,14 @@ func (l *links) add(u *url.URL, sintf string, linkType linkType) error {
 			}
 			options.priority = uint8(pi)
 		}
+		if p := u.Query().Get("cost"); p != "" {
+			c, err := strconv.ParseUint(p, 10, 8)
+			if err != nil {
+				retErr = ErrLinkCostInvalid
+				return
+			}
+			options.cost = uint8(c)
+		}
 		if p := u.Query().Get("password"); p != "" {
 			if len(p) > blake2b.Size {
 				retErr = ErrLinkPasswordInvalid
@@ -448,6 +458,13 @@ func (l *links) listen(u *url.URL, sintf string) (*Listener, error) {
 		}
 		options.priority = uint8(pi)
 	}
+	if p := u.Query().Get("cost"); p != "" {
+		c, err := strconv.ParseUint(p, 10, 8)
+		if err != nil {
+			return nil, ErrLinkCostInvalid
+		}
+		options.cost = uint8(c)
+	}
 	if p := u.Query().Get("password"); p != "" {
 		if len(p) > blake2b.Size {
 			return nil, ErrLinkPasswordInvalid
@@ -567,6 +584,7 @@ func (l *links) handler(linkType linkType, options linkOptions, conn net.Conn, s
 	meta := version_getBaseMetadata()
 	meta.publicKey = l.core.public
 	meta.priority = options.priority
+	meta.cost = options.cost
 	metaBytes, err := meta.encode(l.core.secret, options.password)
 	if err != nil {
 		return fmt.Errorf("failed to generate handshake: %w", err)
@@ -628,17 +646,20 @@ func (l *links) handler(linkType linkType, options linkOptions, conn net.Conn, s
 	remoteAddr := net.IP(address.AddrForKey(meta.publicKey)[:]).String()
 	remoteStr := fmt.Sprintf("%s@%s", remoteAddr, conn.RemoteAddr())
 	localStr := conn.LocalAddr()
-	priority := options.priority
+	cost, priority := options.cost, options.priority
 	if meta.priority > priority {
 		priority = meta.priority
 	}
+	if meta.cost > cost {
+		cost = meta.cost
+	}
 	l.core.log.Infof("Connected %s: %s, source %s",
 		dir, remoteStr, localStr)
 	if success != nil {
 		success()
 	}
 
-	err = l.core.HandleConn(meta.publicKey, conn, priority)
+	err = l.core.HandleConn(meta.publicKey, conn, cost, priority)
 	switch err {
 	case io.EOF, net.ErrClosed, nil:
 		l.core.log.Infof("Disconnected %s: %s, source %s",

src/core/version.go

@@ -22,6 +22,7 @@ type version_metadata struct {
 	minorVer  uint16
 	publicKey ed25519.PublicKey
 	priority  uint8
+	cost      uint8
 }
 
 const (
@@ -36,6 +37,7 @@ const (
 	metaVersionMinor               // uint16
 	metaPublicKey                  // [32]byte
 	metaPriority                   // uint8
+	metaCost                       // uint8
 )
 
 // Gets a base metadata with no keys set, but with the correct version numbers.
@@ -64,9 +66,17 @@ func (m *version_metadata) encode(privateKey ed25519.PrivateKey, password []byte
 	bs = binary.BigEndian.AppendUint16(bs, ed25519.PublicKeySize)
 	bs = append(bs, m.publicKey[:]...)
 
+	if m.priority > 0 {
 		bs = binary.BigEndian.AppendUint16(bs, metaPriority)
 		bs = binary.BigEndian.AppendUint16(bs, 1)
 		bs = append(bs, m.priority)
+	}
+
+	if m.cost > 0 {
+		bs = binary.BigEndian.AppendUint16(bs, metaCost)
+		bs = binary.BigEndian.AppendUint16(bs, 1)
+		bs = append(bs, m.cost)
+	}
 
 	hasher, err := blake2b.New512(password)
 	if err != nil {
@@ -126,6 +136,9 @@ func (m *version_metadata) decode(r io.Reader, password []byte) error {
 
 		case metaPriority:
 			m.priority = bs[0]
+
+		case metaCost:
+			m.cost = bs[0]
 		}
 		bs = bs[oplen:]
 	}

src/core/version_test.go

@@ -52,6 +52,9 @@ func TestVersionRoundtrip(t *testing.T) {
 			{majorVer: 258, minorVer: 259},
 			{majorVer: 3, minorVer: 5, priority: 6},
 			{majorVer: 260, minorVer: 261, priority: 7},
+			{majorVer: 258, minorVer: 259, cost: 5},
+			{majorVer: 3, minorVer: 5, priority: 6, cost: 12},
+			{majorVer: 260, minorVer: 261, priority: 7, cost: 1},
 		} {
 			// Generate a random public key for each time, since it is
 			// a required field.

src/multicast/multicast.go

@@ -45,6 +45,7 @@ type interfaceInfo struct {
 	listen   bool
 	port     uint16
 	priority uint8
+	cost     uint8
 	password []byte
 	hash     []byte
 }
@@ -214,6 +215,7 @@ func (m *Multicast) _getAllowedInterfaces() map[string]*interfaceInfo {
 				listen:   ifcfg.Listen,
 				port:     ifcfg.Port,
 				priority: ifcfg.Priority,
+				cost:     ifcfg.Cost,
 				password: []byte(ifcfg.Password),
 				hash:     hasher.Sum(nil),
 			}
@@ -314,6 +316,7 @@ func (m *Multicast) _announce() {
 				// No listener was found - let's create one
 				v := &url.Values{}
 				v.Add("priority", fmt.Sprintf("%d", info.priority))
+				v.Add("cost", fmt.Sprintf("%d", info.cost))
 				v.Add("password", string(info.password))
 				u := &url.URL{
 					Scheme:   "tls",
@@ -428,6 +431,7 @@ func (m *Multicast) listen() {
 			v := &url.Values{}
 			v.Add("key", hex.EncodeToString(adv.PublicKey))
 			v.Add("priority", fmt.Sprintf("%d", info.priority))
+			v.Add("cost", fmt.Sprintf("%d", info.cost))
 			v.Add("password", string(info.password))
 			u := &url.URL{
 				Scheme:   "tls",

src/multicast/options.go

@@ -21,6 +21,7 @@ type MulticastInterface struct {
 	Listen   bool
 	Port     uint16
 	Priority uint8
+	Cost     uint8
 	Password string
 }