From 166c409bc42627d9e19517f6ce121c39d0f52b65 Mon Sep 17 00:00:00 2001
From: Andre Renaud <andre@designa-electronics.com>
Date: Thu, 5 May 2016 07:28:08 -0600
Subject: net: Handle an empty bootp extension section

Avoid generating this section if there is nothing in it.

Signed-off-by: Andre Renaud <andre@designa-electronics.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
---
 net/bootp.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/net/bootp.c b/net/bootp.c
index aa6cdf0a47..42e14eda41 100644
--- a/net/bootp.c
+++ b/net/bootp.c
@@ -673,6 +673,15 @@ static int bootp_extended(u8 *e)
 
 	*e++ = 255;		/* End of the list */
 
+	/*
+	 * If nothing in list, remove it altogether. Some DHCP servers get
+	 * upset by this minor faux pas and do not respond at all.
+	 */
+	if (e == start + 3) {
+		printf("*** Warning: no DHCP options requested\n");
+		e -= 3;
+	}
+
 	return e - start;
 }
 #endif
-- 
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