From 59c83ef10e76614f8fb743b4f05ba2d7417ba9cc Mon Sep 17 00:00:00 2001
From: Simon Goldschmidt <goldsimon@gmx.de>
Date: Wed, 22 Feb 2012 20:55:27 +0100
Subject: [PATCH] httpd: ensure tcp_write() isn't called with len==0

---
 apps/httpserver_raw/httpd.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/apps/httpserver_raw/httpd.c b/apps/httpserver_raw/httpd.c
index e567a3f..75dd76e 100644
--- a/apps/httpserver_raw/httpd.c
+++ b/apps/httpserver_raw/httpd.c
@@ -610,6 +610,9 @@ http_write(struct tcp_pcb *pcb, const void* ptr, u16_t *length, u8_t apiflags)
    err_t err;
    LWIP_ASSERT("length != NULL", length != NULL);
    len = *length;
+   if (len == 0) {
+     return ERR_OK;
+   }
    do {
      LWIP_DEBUGF(HTTPD_DEBUG | LWIP_DBG_TRACE, ("Trying go send %d bytes\n", len));
      err = tcp_write(pcb, ptr, len, apiflags);