mtu settings and fix mss

bigeagle · Nov 2, 2013 · a5940b2 · a5940b2
1 parent 693f7aa
commit a5940b2
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Showing 6 changed files with 55 additions and 10 deletions.
diff --git a/hop/client.go b/hop/client.go
@@ -78,6 +78,9 @@ func NewClient(cfg HopClientConfig) error {
         return err
     }
 
+    if cfg.MTU != 0 {
+        MTU = cfg.MTU
+    }
 
     hopClient := new(HopClient)
     rand.Read(hopClient.sid[:])
@@ -168,7 +171,7 @@ func (clt *HopClient) handleInterface() {
         }
     }()
 
-    frame := make([]byte, MTU)
+    frame := make([]byte, IFACE_BUFSIZE)
     for {
         n, err := clt.iface.Read(frame)
         if err != nil {
@@ -221,7 +224,7 @@ func (clt *HopClient) handleUDP(server string) {
     }()
 
     // add route through net gateway
-    if clt.cfg.Redirect_gateway {
+    if clt.cfg.Redirect_gateway && (!clt.cfg.Local) {
         if atomic.CompareAndSwapInt32(&clt.srvRoute, 0, 1) {
             if udpAddr, ok := udpConn.RemoteAddr().(*net.UDPAddr); ok {
                 srvIP := udpAddr.IP.To4()
@@ -327,7 +330,9 @@ func (clt *HopClient) handleHandshakeAck(u *net.UDPConn, hp *HopPacket) {
         ip := net.IP(_ip)
         subnet := &net.IPNet{_net, _mask}
         setTunIP(clt.iface, ip, subnet)
-
+        if clt.cfg.FixMSS {
+            fixMSS(clt.iface.Name())
+        }
         res := atomic.CompareAndSwapInt32(&clt.state, HOP_STAT_HANDSHAKE, HOP_STAT_WORKING)
         if !res {
             logger.Error("Client state not expected: %d", clt.state)
@@ -368,8 +373,12 @@ func (clt *HopClient) cleanUp() {
         delRoute("0.0.0.0/1")
         delRoute("128.0.0.0/1")
     }
+    if clt.cfg.FixMSS {
+        clearMSS(clt.iface.Name())
+    }
+
 
-    timeout := time.After(5 * time.Second)
+    timeout := time.After(3 * time.Second)
     if clt.state != HOP_STAT_INIT {
         clt.finishSession()
     }

diff --git a/hop/common.go b/hop/common.go
@@ -24,7 +24,8 @@ import (
 
 var logger = logging.GetLogger()
 
+var MTU = 1400
+
 const (
-    MTU = 1400
-    IFACE_BUFSIZE = 1500
+    IFACE_BUFSIZE = 2000
 )
diff --git a/hop/config.go b/hop/config.go
@@ -205,6 +205,7 @@ type HopServerConfig struct {
     HopStart int
     HopEnd int
     Addr string
+    MTU int
     Key string
     MorphMethod string
 }
@@ -215,7 +216,8 @@ type HopClientConfig struct {
     HopStart int
     HopEnd int
     Key string
-    MTU string
+    MTU int
+    FixMSS bool
     Local bool
     MorphMethod string
     Redirect_gateway bool

diff --git a/hop/iface.go b/hop/iface.go
@@ -45,7 +45,7 @@ func newTun(name string) (iface *water.Interface, err error) {
     }
     logger.Info("interface %v created", iface.Name())
 
-    sargs := fmt.Sprintf("link set dev %s up mtu %d", iface.Name(), MTU)
+    sargs := fmt.Sprintf("link set dev %s up mtu %d qlen 100", iface.Name(), MTU)
     args := strings.Split(sargs, " ")
     cmd := exec.Command("ip", args...)
     logger.Info("ip %s", sargs)
@@ -231,3 +231,32 @@ func unredirectPort(from, to string) error {
     }
     return nil
 }
+
+func fixMSS(iface string) error {
+    mss := MTU - 40
+    logger.Info("Fix MSS with iptables to %d", mss)
+    sargs := fmt.Sprintf("-I FORWARD -o %s -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss %d", iface, mss)
+    args := strings.Split(sargs, " ")
+    cmd := exec.Command("iptables", args...)
+    err := cmd.Run()
+
+    if err != nil {
+        return err
+    }
+    return nil
+}
+
+func clearMSS(iface string) error {
+    mss := MTU - 40
+    logger.Info("Clean MSS fix", mss)
+    sargs := fmt.Sprintf("-D FORWARD -o %s -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss %d", iface, mss)
+    args := strings.Split(sargs, " ")
+    cmd := exec.Command("iptables", args...)
+    err := cmd.Run()
+
+    if err != nil {
+        return err
+    }
+
+    return nil
+}
diff --git a/hop/server.go b/hop/server.go
@@ -75,6 +75,10 @@ func NewServer(cfg HopServerConfig) error {
         return err
     }
 
+    if cfg.MTU != 0 {
+        MTU = cfg.MTU
+    }
+
     hopServer := new(HopServer)
     hopServer.fromNet = make(chan *udpPacket, 32)
     hopServer.fromIface = make(chan []byte, 32)
@@ -140,7 +144,7 @@ func NewServer(cfg HopServerConfig) error {
         }
     }()
 
-    buf := make([]byte, MTU)
+    buf := make([]byte, IFACE_BUFSIZE)
     for {
         n, err := iface.Read(buf)
         if err != nil {

diff --git a/main.go b/main.go
@@ -29,7 +29,7 @@ import (
 var srvMode, cltMode, debug, getVersion bool
 var cfgFile string
 
-var VERSION = "0.3dev"
+var VERSION = "0.3alpha1"
 
 func main() {
     flag.BoolVar(&getVersion, "version", false, "Get Version info")