Re: [lwip-users] Transmission stall after ARP broadcast

[address@hidden]

On 15.02.2018 16:05, Stephan Hilchenbach wrote:

Hello Experts,

 

I have a problem with my Ethernet driver connecting a Ti AM335x CPSW switch to the LwIP stack v1.4.1.

1.4.1 is rather old. There have been numerous bugs fixed since then.

The port stops transmitting after some minutes or hours. The DMA hardware register shows no errors but the transmission stalled. The DMA does not process further packets, but the content of the next packets looks OK.

When I run Wireshark I observe always the same sequence. Every time before the port stops transmission, the last packet sent was an ARP broadcast to the connected host "TexasIns_e4:2a:20 Broadcast ARP Who has 192.168.1.31? Tell 192.168.1.211". Curiously this is the only time the LwIP generates this request after connection was established. There are no other ARP broadcasts until the Tx stall. Attached is a screenshot.

A screenshot? WTF? If this is a screenshot of a wireshark log, please attach a pcap file instead.

I have two questions about this:

1. What is the reason for the LwIP to generate this ARP broadcast during transmission?

Don't know. Attach a pcap including an explanation of which IPs we see, which device has which address and what they do. I'm too lazy to try to find that out myself. And I could be wrong.

2. Can the LwIP cause a hardware Tx port to stall (because of the packet content)?

No. In general, lwIP has *nothing* to do with your hardware. The netif driver is responsible for that.

Simon