Add bandwidth limiter

cmd/ck-client/ck-client.go

@@ -140,17 +140,11 @@ func main() {
 		log.Fatal("TicketTimeHint cannot be empty or 0")
 	}
 
-	initRemoteConn, err := makeRemoteConn(sta)
-	if err != nil {
-		log.Fatalf("Failed to establish connection to remote: %v\n", err)
-	}
-
 	obfs := util.MakeObfs(sta.SID)
 	deobfs := util.MakeDeobfs(sta.SID)
-	// TODO: where to put obfs deobfs and rtd?
-	sesh := mux.MakeSession(0, initRemoteConn, obfs, deobfs, util.ReadTillDrain)
+	sesh := mux.MakeSession(0, 1e9, 1e9, obfs, deobfs, util.ReadTillDrain)
 
-	for i := 0; i < sta.NumConn-1; i++ {
+	for i := 0; i < sta.NumConn; i++ {
 		go func() {
 			conn, err := makeRemoteConn(sta)
 			if err != nil {

cmd/ck-server/ck-server.go

@@ -102,12 +102,11 @@ func dispatchConnection(conn net.Conn, sta *server.State) {
 		var arrSID [32]byte
 		copy(arrSID[:], SID)
 		var sesh *mux.Session
-		if sesh = sta.GetSession(arrSID); sesh != nil {
-			sesh.AddConnection(conn)
-		} else {
-			sesh = mux.MakeSession(0, conn, util.MakeObfs(SID), util.MakeDeobfs(SID), util.ReadTillDrain)
+		if sesh = sta.GetSession(arrSID); sesh == nil {
+			sesh = mux.MakeSession(0, 1e9, 1e9, util.MakeObfs(SID), util.MakeDeobfs(SID), util.ReadTillDrain)
 			sta.PutSession(arrSID, sesh)
 		}
+		sesh.AddConnection(conn)
 		go func() {
 			for {
 				newStream, err := sesh.AcceptStream()

internal/multiplex/session.go

@@ -10,8 +10,6 @@ import (
 const (
 	// Copied from smux
 	acceptBacklog = 1024
-
-	closeBacklog = 512
 )
 
 var ErrBrokenSession = errors.New("broken session")
@@ -45,7 +43,7 @@ type Session struct {
 }
 
 // 1 conn is needed to make a session
-func MakeSession(id int, conn net.Conn, obfs func(*Frame) []byte, deobfs func([]byte) *Frame, obfsedReader func(net.Conn, []byte) (int, error)) *Session {
+func MakeSession(id int, uprate, downrate float64, obfs func(*Frame) []byte, deobfs func([]byte) *Frame, obfsedReader func(net.Conn, []byte) (int, error)) *Session {
 	sesh := &Session{
 		id:           id,
 		obfs:         obfs,
@@ -56,7 +54,7 @@ func MakeSession(id int, conn net.Conn, obfs func(*Frame) []byte, deobfs func([]
 		acceptCh:     make(chan *Stream, acceptBacklog),
 		die:          make(chan struct{}),
 	}
-	sesh.sb = makeSwitchboard(conn, sesh)
+	sesh.sb = makeSwitchboard(sesh, uprate, downrate)
 	return sesh
 }
 

internal/multiplex/switchboard.go

@@ -1,22 +1,22 @@
 package multiplex
 
 import (
+	"errors"
 	"log"
 	"net"
 	"sync"
 	"sync/atomic"
-)
 
-const (
-	sentNotifyBacklog = 1024
-	dispatchBacklog   = 10240
-	newConnBacklog    = 8
+	"github.com/juju/ratelimit"
 )
 
 // switchboard is responsible for keeping the reference of TLS connections between client and server
 type switchboard struct {
 	session *Session
 
+	wtb *ratelimit.Bucket
+	rtb *ratelimit.Bucket
+
 	optimum atomic.Value
 	cesM    sync.RWMutex
 	ces     []*connEnclave
@@ -33,24 +33,25 @@ type connEnclave struct {
 }
 
 // It takes at least 1 conn to start a switchboard
-func makeSwitchboard(conn net.Conn, sesh *Session) *switchboard {
+// TODO: does it really?
+func makeSwitchboard(sesh *Session, uprate, downrate float64) *switchboard {
 	sb := &switchboard{
 		session: sesh,
+		wtb:     ratelimit.NewBucketWithRate(uprate, int64(uprate)),
+		rtb:     ratelimit.NewBucketWithRate(downrate, int64(downrate)),
 		ces:     []*connEnclave{},
 	}
-	ce := &connEnclave{
-		sb:         sb,
-		remoteConn: conn,
-		sendQueue:  0,
-	}
-	sb.ces = append(sb.ces, ce)
-	go sb.deplex(ce)
-
 	return sb
 }
 
+var errNilOptimum error = errors.New("The optimal connection is nil")
+
 func (sb *switchboard) send(data []byte) (int, error) {
 	ce := sb.optimum.Load().(*connEnclave)
+	if ce == nil {
+		return 0, errNilOptimum
+	}
+	sb.wtb.Wait(int64(len(data)))
 	atomic.AddUint32(&ce.sendQueue, uint32(len(data)))
 	go sb.updateOptimum()
 	n, err := ce.remoteConn.Write(data)
@@ -118,6 +119,7 @@ func (sb *switchboard) deplex(ce *connEnclave) {
 	buf := make([]byte, 20480)
 	for {
 		i, err := sb.session.obfsedReader(ce.remoteConn, buf)
+		sb.rtb.Wait(int64(i))
 		if err != nil {
 			log.Println(err)
 			go ce.remoteConn.Close()