Don't overfill the mux's output buffer.

Otherwise a single busy stream can ruin it for everybody.

client.py

@@ -87,6 +87,8 @@ def _main(listener, listenport, use_server, remotename, subnets):
         for s in handlers:
             if s.socks & ready:
                 s.callback()
+        mux.callback()
+        mux.check_fullness()
 
 
 def main(listenip, use_server, remotename, subnets):

server.py

@@ -43,3 +43,5 @@ def main():
         for s in handlers:
             if s.socks & ready:
                 s.callback()
+        mux.callback()
+        mux.check_fullness()

ssnet.py

@@ -215,6 +215,7 @@ class Mux(Handler):
         self.want = 0
         self.inbuf = ''
         self.outbuf = []
+        self.too_full = False
         self.send(0, CMD_PING, 'chicken')
 
     def next_channel(self):
@@ -226,6 +227,17 @@ class Mux(Handler):
             if not self.channels.get(self.chani):
                 return self.chani
 
+    def amount_queued(self):
+        return sum(len(b) for b in self.outbuf)
+            
+    def check_fullness(self):
+        self.too_full = (self.amount_queued() > 32768)
+        ob = []
+        for b in self.outbuf:
+            (s1,s2,c) = struct.unpack('!ccH', b[:4])
+            ob.append(c)
+        log('outbuf: %d %r\n' % (self.amount_queued(), ob,))
+        
     def send(self, channel, cmd, data):
         data = str(data)
         assert(len(data) <= 65535)
@@ -233,8 +245,6 @@ class Mux(Handler):
         self.outbuf.append(p)
         debug2(' > channel=%d cmd=%s len=%d\n' 
                % (channel, cmd_to_name[cmd], len(data)))
-        #log('Mux: send queue is %d/%d\n' 
-        #    % (len(self.outbuf), sum(len(b) for b in self.outbuf)))
 
     def got_packet(self, channel, cmd, data):
         debug2('<  channel=%d cmd=%s len=%d\n' 
@@ -309,6 +319,7 @@ class MuxWrapper(SockWrapper):
         self.mux = mux
         self.channel = channel
         self.mux.channels[channel] = self.got_packet
+        self.socks = []
         debug2('new channel: %d\n' % channel)
 
     def __del__(self):
@@ -328,8 +339,10 @@ class MuxWrapper(SockWrapper):
             self.mux.send(self.channel, CMD_EOF, '')
 
     def uwrite(self, buf):
-        if len(buf) > 65535:
-            buf = buf[:32768]
+        if self.mux.too_full:
+            return 0  # too much already enqueued
+        if len(buf) > 2048:
+            buf = buf[:2048]
         self.mux.send(self.channel, CMD_DATA, buf)
         return len(buf)