From 12610e9989b7754154ef3ccd2cece674570f40c8 Mon Sep 17 00:00:00 2001
From: bigeagle <justin.w.xd@gmail.com>
Date: Tue, 10 Dec 2013 16:04:57 +0800
Subject: [PATCH] move fix mss to gohop server

---
 hop/client.go |  4 ++--
 hop/config.go |  1 +
 hop/iface.go  | 19 +++++++++++++++----
 hop/server.go | 27 ++++++++++++++++-----------
 main.go       |  2 +-
 5 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/hop/client.go b/hop/client.go
index ab382e3..c4c1b89 100644
--- a/hop/client.go
+++ b/hop/client.go
@@ -333,7 +333,7 @@ func (clt *HopClient) handleHandshakeAck(u *net.UDPConn, hp *HopPacket) {
         subnet := &net.IPNet{_net, _mask}
         setTunIP(clt.iface, ip, subnet)
         if clt.cfg.FixMSS {
-            fixMSS(clt.iface.Name())
+            fixMSS(clt.iface.Name(), false)
         }
         res := atomic.CompareAndSwapInt32(&clt.state, HOP_STAT_HANDSHAKE, HOP_STAT_WORKING)
         if !res {
@@ -376,7 +376,7 @@ func (clt *HopClient) cleanUp() {
         delRoute("128.0.0.0/1")
     }
     if clt.cfg.FixMSS {
-        clearMSS(clt.iface.Name())
+        clearMSS(clt.iface.Name(), false)
     }
 
 
diff --git a/hop/config.go b/hop/config.go
index 04415d5..70248d6 100644
--- a/hop/config.go
+++ b/hop/config.go
@@ -208,6 +208,7 @@ type HopServerConfig struct {
     Addr string
     MTU int
     Key string
+    FixMSS bool
     MorphMethod string
 }
 
diff --git a/hop/iface.go b/hop/iface.go
index fb5e54b..d38beb2 100644
--- a/hop/iface.go
+++ b/hop/iface.go
@@ -232,10 +232,15 @@ func unredirectPort(from, to string) error {
     return nil
 }
 
-func fixMSS(iface string) error {
+func fixMSS(iface string, is_server bool) 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)
+    io := "o"
+    if is_server {
+        io = "i"
+    }
+
+    sargs := fmt.Sprintf("-I FORWARD -%s %s -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss %d", io, iface, mss)
     args := strings.Split(sargs, " ")
     cmd := exec.Command("iptables", args...)
     err := cmd.Run()
@@ -246,10 +251,16 @@ func fixMSS(iface string) error {
     return nil
 }
 
-func clearMSS(iface string) error {
+func clearMSS(iface string, is_server bool) 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)
+    io := "o"
+
+    if is_server {
+        io = "i"
+    }
+    sargs := fmt.Sprintf("-D FORWARD -%s %s -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss %d", io, iface, mss)
+
     args := strings.Split(sargs, " ")
     cmd := exec.Command("iptables", args...)
     err := cmd.Run()
diff --git a/hop/server.go b/hop/server.go
index a20565c..0b534bc 100644
--- a/hop/server.go
+++ b/hop/server.go
@@ -25,9 +25,9 @@ import (
     "bytes"
     "fmt"
     "net"
-//     "os"
-//     "os/signal"
-//     "syscall"
+    "os"
+    "os/signal"
+    "syscall"
     "time"
     "sync/atomic"
     "sync"
@@ -101,6 +101,10 @@ func NewServer(cfg HopServerConfig) error {
     hopServer.ipnet = &net.IPNet{ip, subnet.Mask}
     hopServer.ippool.subnet = subnet
 
+    if cfg.FixMSS {
+        fixMSS(iface.Name(), true)
+    }
+
     // traffic morpher
     switch cfg.MorphMethod {
     case "randsize":
@@ -119,6 +123,7 @@ func NewServer(cfg HopServerConfig) error {
     //     defer hopServer.cleanUp()
     //     redirectPort(cfg.HopRange, cfg.Port)
     // }()
+    go hopServer.cleanUp()
 
     // serve for multiple ports
     for idx, port := 0, cfg.HopStart; port <= cfg.HopEnd; port++ {
@@ -408,11 +413,11 @@ func (srv *HopServer) handleFinish(u *udpPacket, hp *HopPacket) {
     srv.toClient(hpeer, HOP_FLG_FIN | HOP_FLG_ACK, []byte{}, false)
 }
 
-// func (srv *HopServer) cleanUp() {
-//     c := make(chan os.Signal, 1)
-//     signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
-//     <-c
-//
-//     unredirectPort(srv.cfg.HopRange, srv.cfg.Port)
-//     os.Exit(0)
-// }
+func (srv *HopServer) cleanUp() {
+    c := make(chan os.Signal, 1)
+    signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
+    <-c
+
+    clearMSS(srv.iface.Name(), true)
+    os.Exit(0)
+}
diff --git a/main.go b/main.go
index 2558fc3..4577087 100644
--- a/main.go
+++ b/main.go
@@ -29,7 +29,7 @@ import (
 var srvMode, cltMode, debug, getVersion bool
 var cfgFile string
 
-var VERSION = "0.3alpha1"
+var VERSION = "0.3alpha2"
 
 func main() {
     flag.BoolVar(&getVersion, "version", false, "Get Version info")