[U-Boot] [PATCH v2 1/1] net:Fix potential empty DHCP Parameter Request List

[Jason Liu]

Can't get IP address with dhcp due to the dhcp server not
allow the empty param list request under some network env

This patch is based on Gray Remlin's initial patch.

Signed-off-by: Jason Liu <r64343 at freescale.com>
Signed-off-by: Gray Remlin <g_remlin at rocketmail.com>

---
Changes for v2:
  - address the comments from Mike and re-order the code
---
 net/bootp.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/net/bootp.c b/net/bootp.c
index e679f8b..1a71786 100644
--- a/net/bootp.c
+++ b/net/bootp.c
@@ -456,6 +456,10 @@ static int DhcpExtended (u8 * e, int message_type, IPaddr_t ServerID, IPaddr_t R
 	*e++  = 42;
 	*cnt += 1;
 #endif
+	/* no options, so back up to avoid sending an empty request list */
+	if (*cnt == 0)
+		e -= 2;
+
 	*e++  = 255;		/* End of the list */
 
 	/* Pad to minimal length */
-- 
1.7.0.4