[U-Boot] [PATCH 10/10] net: Don't overwrite waiting packets with asynchronous replies

[Simon Glass]

On 24 July 2018 at 15:40, Joe Hershberger <joe.hershberger at ni.com> wrote:
> Peter originally sent a fix, but it breaks a number of other things.
> This addresses the original reported issue in a different way.
>
> That report was:
>
>> U-Boot has 1 common buffer to send Ethernet frames, pointed to by
>> net_tx_packet.  When sending to an IP address without knowing the MAC
>> address, U-Boot makes an ARP request (using the arp_tx_packet buffer)
>> to find out the MAC address of the IP addressr. When a matching ARP
>> reply is received, U-Boot continues sending the frame stored in the
>> net_tx_packet buffer.
>>
>> However, in the mean time, if U-Boot needs to send out any network
>> packets (e.g. replying ping packets or ARP requests for its own IP
>> address etc.), it will use the net_tx_packet buffer to prepare the
>> new packet. Thus this buffer is no longer the original packet meant
>> to be transmitted after the ARP reply. The original packet will be
>> lost.
>
> This instead uses the ARP tx buffer to send async replies in the case
> where we are actively waiting for an ARP reply.
>
> Signed-off-by: Joe Hershberger <joe.hershberger at ni.com>
>
> Reported-by: Tran Tien Dat <peter.trantiendat at gmail.com>
> ---
>
>  include/net.h | 8 ++++++++
>  net/arp.c     | 9 +++++----
>  net/arp.h     | 1 +
>  net/net.c     | 8 ++++++++
>  net/ping.c    | 7 +++++--
>  test/dm/eth.c | 6 ++----
>  6 files changed, 29 insertions(+), 10 deletions(-)

Reviewed-by: Simon Glass <sjg at chromium.org>