[U-Boot] [PATCH V2] net: bootp: Ignore packets whose yiaddr is 0

[Peng Fan <van.freenix@gmail.com>]

From: Peng Fan <peng.fan@nxp.com>

When doing `dhcp`, there is a bad dhcp server in my network
which always reply dhcp request with yiaddr 0, which cause
uboot can not successfully get ipaddr from the good dhcp server.
But the Linux PC can get the ip address even if there is a bad
dhcp server. This patch is to fix that even if there is a bad
dhcp server, uboot can still get ipaddr and tftp work ok.

The way is to ignore the packets from the bad dhcp server by filtering
out the yiaddr whose value is 0.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
---

Changes V2:
 Take Wolfgang's suggestion, move the code after debug message.

 net/bootp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/bootp.c b/net/bootp.c
index 8aeddb0..8da2e9b 100644
--- a/net/bootp.c
+++ b/net/bootp.c
@@ -995,6 +995,9 @@ static void dhcp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
 	debug("DHCPHandler: got DHCP packet: (src=%d, dst=%d, len=%d) state: "
 	      "%d\n", src, dest, len, dhcp_state);
 
+	if (net_read_ip(&bp->bp_yiaddr).s_addr == 0)
+		return;
+
 	switch (dhcp_state) {
 	case SELECTING:
 		/*
-- 
2.6.2