net: Don't overwrite waiting packets with asynchronous replies

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@ni.com>

Reported-by: Tran Tien Dat <peter.trantiendat@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/arp.h b/net/arp.h
index afb86958f3..25b3c00d5c 100644
--- a/net/arp.h
+++ b/net/arp.h
@@ -20,6 +20,7 @@ extern uchar *arp_wait_packet_ethaddr;
 extern int arp_wait_tx_packet_size;
 extern ulong arp_wait_timer_start;
 extern int arp_wait_try;
+extern uchar *arp_tx_packet;
 
 void arp_init(void);
 void arp_request(void);