Merge pull request #2498 from AudriusButkevicius/relaystuff

Change the way relays are chosen, add RelayFull message.

lib/relay/client/dynamic.go

@@ -6,6 +6,7 @@ import (
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
+	"math/rand"
 	"net/http"
 	"net/url"
 	"sort"
@@ -82,7 +83,7 @@ func (c *dynamicClient) Serve() {
 		addrs = append(addrs, ruri.String())
 	}
 
-	for _, addr := range relayAddressesSortedByLatency(addrs) {
+	for _, addr := range relayAddressesOrder(addrs) {
 		select {
 		case <-c.stop:
 			l.Debugln(c, "stopping")
@@ -176,42 +177,44 @@ type dynamicAnnouncement struct {
 	}
 }
 
-// relayAddressesSortedByLatency adds local latency to the relay, and sorts them
-// by sum latency, and returns the addresses.
-func relayAddressesSortedByLatency(input []string) []string {
-	relays := make(relayList, len(input))
-	for i, relay := range input {
-		if latency, err := osutil.GetLatencyForURL(relay); err == nil {
-			relays[i] = relayWithLatency{relay, int(latency / time.Millisecond)}
-		} else {
-			relays[i] = relayWithLatency{relay, int(time.Hour / time.Millisecond)}
+// relayAddressesOrder checks the latency to each relay, rounds latency down to
+// the closest 50ms, and puts them in buckets of 50ms latency ranges. Then
+// shuffles each bucket, and returns all addresses starting with the ones from
+// the lowest latency bucket, ending with the highest latency buceket.
+func relayAddressesOrder(input []string) []string {
+	buckets := make(map[int][]string)
+
+	for _, relay := range input {
+		latency, err := osutil.GetLatencyForURL(relay)
+		if err != nil {
+			latency = time.Hour
 		}
+
+		id := int(latency/time.Millisecond) / 50
+
+		buckets[id] = append(buckets[id], relay)
 	}
 
-	sort.Sort(relays)
-
-	addresses := make([]string, len(relays))
-	for i, relay := range relays {
-		addresses[i] = relay.relay
+	var ids []int
+	for id, bucket := range buckets {
+		shuffle(bucket)
+		ids = append(ids, id)
 	}
+
+	sort.Ints(ids)
+
+	addresses := make([]string, len(input))
+
+	for _, id := range ids {
+		addresses = append(addresses, buckets[id]...)
+	}
+
 	return addresses
 }
 
-type relayWithLatency struct {
-	relay   string
-	latency int
-}
-
-type relayList []relayWithLatency
-
-func (l relayList) Len() int {
-	return len(l)
-}
-
-func (l relayList) Less(a, b int) bool {
-	return l[a].latency < l[b].latency
-}
-
-func (l relayList) Swap(a, b int) {
-	l[a], l[b] = l[b], l[a]
+func shuffle(slice []string) {
+	for i := len(slice) - 1; i > 0; i-- {
+		j := rand.Intn(i + 1)
+		slice[i], slice[j] = slice[j], slice[i]
+	}
 }

lib/relay/client/static.go

@@ -119,6 +119,10 @@ func (c *staticClient) Serve() {
 				}
 				c.invitations <- msg
 
+			case protocol.RelayFull:
+				l.Infoln("Disconnected from relay due to it becoming full.")
+				return
+
 			default:
 				l.Infoln("Relay: protocol error: unexpected message %v", msg)
 				return
@@ -240,6 +244,9 @@ func (c *staticClient) join() error {
 			return fmt.Errorf("Incorrect response code %d: %s", msg.Code, msg.Message)
 		}
 
+	case protocol.RelayFull:
+		return fmt.Errorf("relay full")
+
 	default:
 		return fmt.Errorf("protocol error: expecting response got %v", msg)
 	}

lib/relay/protocol/packets.go

@@ -20,6 +20,7 @@ const (
 	messageTypeResponse
 	messageTypeConnectRequest
 	messageTypeSessionInvitation
+	messageTypeRelayFull
 )
 
 type header struct {
@@ -31,6 +32,7 @@ type header struct {
 type Ping struct{}
 type Pong struct{}
 type JoinRelayRequest struct{}
+type RelayFull struct{}
 
 type JoinSessionRequest struct {
 	Key []byte // max:32

lib/relay/protocol/packets_xdr.go

@@ -256,6 +256,63 @@ func (o *JoinRelayRequest) DecodeXDRFrom(xr *xdr.Reader) error {
 
 /*
 
+RelayFull Structure:
+
+ 0                   1                   2                   3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+struct RelayFull {
+}
+
+*/
+
+func (o RelayFull) EncodeXDR(w io.Writer) (int, error) {
+	var xw = xdr.NewWriter(w)
+	return o.EncodeXDRInto(xw)
+}
+
+func (o RelayFull) MarshalXDR() ([]byte, error) {
+	return o.AppendXDR(make([]byte, 0, 128))
+}
+
+func (o RelayFull) MustMarshalXDR() []byte {
+	bs, err := o.MarshalXDR()
+	if err != nil {
+		panic(err)
+	}
+	return bs
+}
+
+func (o RelayFull) AppendXDR(bs []byte) ([]byte, error) {
+	var aw = xdr.AppendWriter(bs)
+	var xw = xdr.NewWriter(&aw)
+	_, err := o.EncodeXDRInto(xw)
+	return []byte(aw), err
+}
+
+func (o RelayFull) EncodeXDRInto(xw *xdr.Writer) (int, error) {
+	return xw.Tot(), xw.Error()
+}
+
+func (o *RelayFull) DecodeXDR(r io.Reader) error {
+	xr := xdr.NewReader(r)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *RelayFull) UnmarshalXDR(bs []byte) error {
+	var br = bytes.NewReader(bs)
+	var xr = xdr.NewReader(br)
+	return o.DecodeXDRFrom(xr)
+}
+
+func (o *RelayFull) DecodeXDRFrom(xr *xdr.Reader) error {
+	return xr.Error()
+}
+
+/*
+
 JoinSessionRequest Structure:
 
  0                   1                   2                   3

lib/relay/protocol/protocol.go

@@ -50,6 +50,9 @@ func WriteMessage(w io.Writer, message interface{}) error {
 	case SessionInvitation:
 		payload, err = msg.MarshalXDR()
 		header.messageType = messageTypeSessionInvitation
+	case RelayFull:
+		payload, err = msg.MarshalXDR()
+		header.messageType = messageTypeRelayFull
 	default:
 		err = fmt.Errorf("Unknown message type")
 	}
@@ -108,6 +111,10 @@ func ReadMessage(r io.Reader) (interface{}, error) {
 		var msg SessionInvitation
 		err := msg.DecodeXDR(r)
 		return msg, err
+	case messageTypeRelayFull:
+		var msg RelayFull
+		err := msg.DecodeXDR(r)
+		return msg, err
 	}
 
 	return nil, fmt.Errorf("Unknown message type")