lwip tftp not working on imx8mm

[Peter Robinson]

Hi Tim,

> I've enabled LWIP on imx8mm_venice to see how it's doing and while
> dhcp/dns/ping/wget appear to work great, tftp is broken.
>
> Enabling LWIP_DEBUG shows the following:
> ip4_input: packet accepted on interface et
> IP packet dropped since it was fragmented (0x2000) (while IP_REASSEMBLY == 0).
>
> I tried enabling IP_REASSEMBLY in lwip but that seems to change the issue to:
> ip4_input: packet accepted on interface et
> ip4_input:
> IP header:
> +-------------------------------+
> | 4 | 5 |  0xc0 |       108     | (v, hl, tos, len)
> +-------------------------------+
> |    10568      |000|       0   | (id, flags, offset)
> +-------------------------------+
> |   64  |    1  |    0xe25b     | (ttl, proto, chksum)
> +-------------------------------+
> |  172  |   24  |    0  |    2  | (src)
> +-------------------------------+
> |  172  |   24  |   21  |  251  | (dest)
> +-------------------------------+
> ip4_input: p->len 108 p->tot_len 108
> Unsupported transport protocol 1
>
> Any ideas what the issue is here?

You reported the same issue some time ago [1] and while I could fine
the original thread in my inbox, I thought we had got to the bottom of
the issue and it had been fixed I couldn't find a follow up thread.
Maybe Fabio can remember as I seem to recall he was the one that got
to the bottom of the issue.

Peter

[1] https://lists.denx.de/pipermail/u-boot/2023-November/538832.html