Re: [lwip-devel] Lwip as a router

[Ghobad Emadi]

Ghobad Emadi wrote:
> Hi everyone,I needed to use lwip as a router last month and? when I searched
> on Google I understood that a lot of people want to use it as a router.
> I have deployed Lwip to use as a router. How can I add this feature to Lwip?

Shouldn't this just work when IP_FORWARDING is enabled? Extended routing capabilites would be missing, but simple routing with a default gateway should work, I think.

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

What did you need to add to make it work for you?

I have add this feature to Lwip source code (and I have tested it) already.

 

> Moreover, is it a useful thing?

In general, we suggest to not use lwIP as a router, since it has been designed for devices, not for networking components where possible failure could disable a whole network. It should work anyway, but if I were to design a router, I'd rather use a more full-blown OS like a BSD or linux...

 I agree with your idea about using full-blown OS rather than Lwip as a router. I didn't want to use Lwip on embedded devices. We wanted to simulate a network with some routers and hosts on Linux for academic and research purposes. Lwip is very light, so it is possible to have a large simulated network. I made some changes in Lwip to support extended routing as well as being a router.

I'm wondering to know that how can I patch Lwip to be used by others as a router?