Re: [lwip-users] UDP packet sending problem

[Kieran Mansley]

On Fri, 2009-06-26 at 11:11 +0200, patrick Deflandre wrote:

> <LF>udp_send: ip_output_if (,,,,IP_PROTO_UDP,)ip_output_if: em0
> <LF>IP header:+-------------------------------+| 4 | 5 |  0x00 |
> 33     | (v, hl, tos, len)
> <LF>+-------------------------------+|        0      |000|       0   |
> (id, flags, offset)
> <LF>+-------------------------------+|   64  |   17  |    0x47b8     |
> (ttl, proto, chksum)
> <LF>+-------------------------------+|  133  |   38  |   20  |  150  |
> (src)
> <LF>+-------------------------------+|  133  |   38  |   20  |   50  |
> (dest)
> <LF>+-------------------------------+netif->output()

It looks like the packet is getting a good way through the stack - as
far as the netif->output() call, so it's done all the UDP and IP parts
without any problem.  I'm not sure what this function pointer will be
set to in your project, but typically this will be something like
etherarp_output().  I would debug what is going on there.  As lwIP is
also failing to respond to the ARP query, I suspect there might be a
problem with ARP.  If not that, then you're into your driver.

Kieran