Re: sys/dev/usb/if_axen.c

[sc.dying%gmail.com@localhost]

On 2023/11/19 11:53, Michael van Elst wrote:
> On Sun, Nov 19, 2023 at 06:40:19AM +0000, sc.dying%gmail.com@localhost wrote:
> 
> There are regular Ethernet headers (padded/align with 0xeeee).
> 
>> 1700366741.414702 axen_uno_rx_loop#0@0:  eeee207b d26f4276 00e04c53 44580800

>>                                   0000   <-- pkt #1

These lines that doesn't start with timestamp are what I add mannually to explain
above line.

> 
>>                                   0ec0                pkt #1    --> <garbage>
>> 1700366741.414722 axen_uno_rx_loop#0@0:  eeee207b d26f4276 00e04c53 44580800
>>                                   0ed0   <-- pkt #2
> 
> 
> No idea what this is, but it doesn't really look like garbage.

I guess these 4 bytes are just garbage to pad up to next 8-bytes
boundary.
In some frames they are 2 bytes long, not looks like FCS.

> 
>>                                   0bd0                pkt #2    --> <garbage>
>> 1700366741.414739 axen_uno_rx_loop#0@0:  0008ec05 00000080 0008ec05 00000080
> 
> 
> What is the format of these (64bit wide?) headers ?

In 88179 rule, first 4 bytes 0x05ec8000 are pkt_len and flags.
pkt_len=0x5ec (0t1516), flags=multicast/broadcast. See also if_axenreg.h.
i've no idea about next 4 bytes 0x80000000.

> 
>>                                   0be0   <  pkt_hdr #1   > <  pkt_hdr #2   >
>> 1700366741.414739 axen_uno_rx_loop#0@0:  00000000 0400e00b 400657b9 c0a80104
>>                                   0bf0  <garbage><recv_hdr><--  garbage  -->
> 
> 
> Greetings,