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

[Peng Fan]

Hi Wolfgang,
On Thu, Jan 07, 2016 at 12:49:42AM +0100, Wolfgang Denk wrote:
>Dear Peng Fan,
>
>In message <1451875796-15860-1-git-send-email-peng.fan at nxp.com> you wrote:
>> 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 at nxp.com>
>> Cc: Joe Hershberger <joe.hershberger at ni.com>
>> ---
>>  net/bootp.c | 3 +++
>>  1 file changed, 3 insertions(+)
>> 
>> diff --git a/net/bootp.c b/net/bootp.c
>> index 8aeddb0..ff2ebbe 100644
>> --- a/net/bootp.c
>> +++ b/net/bootp.c
>> @@ -992,6 +992,9 @@ static void dhcp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
>>  	if (check_reply_packet(pkt, dest, src, len))
>>  		return;
>>  
>> +	if (net_read_ip(&bp->bp_yiaddr).s_addr == 0)
>> +		return;
>> +
>>  	debug("DHCPHandler: got DHCP packet: (src=%d, dst=%d, len=%d) state: "
>>  	      "%d\n", src, dest, len, dhcp_state);
>
>I suggest the return should be done _after_ the debug message.

Yeah. Good suggestion. Will do this in V2.

Thanks,
Peng.

>
>Best regards,
>
>Wolfgang Denk
>
>-- 
>DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
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