Re: [lwip-devel] Lwip as a router

[Simon Goldschmidt]

Ghobad Emadi wrote:
> Yes, simple routing is possible, but I need to use lwip as a
> router with extended routing capabilities. As you know, when
> destination IP of received packet on Lwip does not belong to
> interfaces' subnet, Lwip does not forward it, however
> IP_FORWARDING is enabled.

For this, overriding LWIP_HOOK_IP4_ROUTE() should be enough to select the 
correct interface.

> In addition, I need to have multiple gateway on one interface.

So you would have to change etharp_output() to search for the correct gateway 
for the target IP address, I guess?

I'm not willing to add such a change to the main sources, but I could be talked 
into adding a hook like for ip_route(), I guess. Then, your implementation 
would require storing the multiple gateways in netif->state somewhere, and your 
hook would search them there. The hook would be something like

ip_addr_t* LWIP_HOOK_ETHARP_GET_GW(struct netif* if, ip_addr_t* dst_addr);


Simon