Comment 0 for bug 2021749

SRU Justification:

[Impact]
This change is needed to avoid potential tmfifo console stuck when network interface is down or receiving oversized packets.

[Fix]
Drop the Rx packets in the above cases. Since tmfifo is shared resource for both console and networking. Dropping such network packets can continue to process the fifo and avoid console stuck.

[Test Case]
Same functionality and testing as on BlueField-1/2/2. No functionality change.
Add negative tests:
1. 'ifconfig tmfifo_net0 down' on ARM side during traffic, then verify rshim console doesn't stuck.
2. Config MTU to 4000 on rshim host and send oversized packet with command 'ping 192.168.100.2 -s 2000". It shouldn't cause any stuck.

[Regression Potential]
Same behavior from user perspective.