fixed bug #37184 tcp_write problem for pcbs in the SYN_SENT state

CHANGELOG

@@ -100,6 +100,9 @@ HISTORY
 
  ++ Bugfixes:
 
+  2014-05-20: Simon Goldschmidt
+  * tcp_out.c: fixed bug #37184 tcp_write problem for pcbs in the SYN_SENT state
+
   2014-05-19: Simon Goldschmidt
   * *.h: Fixed bug #35874 reserved identifier violation (removed leading underscores
     from header include guards)

src/core/tcp_out.c

@@ -375,6 +375,7 @@ tcp_write(struct tcp_pcb *pcb, const void *arg, u16_t len, u8_t apiflags)
   err_t err;
   /* don't allocate segments bigger than half the maximum window we ever received */
   u16_t mss_local = LWIP_MIN(pcb->mss, pcb->snd_wnd_max/2);
+  mss_local = mss_local ? mss_local : pcb->mss;
 
 #if LWIP_NETIF_TX_SINGLE_PBUF
   /* Always copy to try to create single pbufs for TX */