[lwip-users] Suppress ARP

[Mathias Zenger]

I have a special problem with ARP.

My application uses UDP protocol and decides at start-up how to configure
the stack/network interface. There is one mode where it uses DHCP/ARP and
then requests packets from a server. Running an other mode it only receives
multicast addressed packets and doesn't necessarily need the DHCP and ARP
options. In this mode a simple dummy IP and gateway address are configured
at start-up.

For some multicast packets I should send a reply to the server. When calling
sento() from the socket API the stack sends out an ARP request which cannot
be answered by anyone due to the used dummy addresses. Accordingly my reply
packet won't be sent.

Question: is there a suitable way to suppress the ARP request for this
special case and send out the datagram instead? Is ARP required at all or
should I simply not define it in lwipopts.h for both modes?

Regards,
Mathias