[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [lwip-users] Sending frames without IP

From: address@hidden
Subject: Re: [lwip-users] Sending frames without IP
Date: Sun, 06 Nov 2011 12:54:33 +0100
User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:7.0.1) Gecko/20110929 Thunderbird/7.0.1

address@hidden wrote:
This works as it should, I can receive broadcast UDP requests directed at a specific port.
I am however unable to respond to the request. (I use broadcast response of course)

udp_sendto() calls ip_route(), which takes a look at netif_is_up(netif_default) and figures that since the default netif is not up, the UDP frame should be dropped.

Is there a way around this? Or do I have to modify ip_route to allow broadcast traffic even when the netif is down?
Either that (you can use LWIP_HOOK_IP4_ROUTE) or use udp_sendto_if() like dhcp does. It is intended behaviour to be able to set a netif down so that it will not be used for normal routing.
Shouldn't netif_is_up() actually indicate if there is a physical link on the interface, and ip_addr=0x00000000 indicate that the interface is unconfigured?
No, netif_is_link_up() is used for the physical link status.
It looks like that was the intention in some places of the code.
If so, that would be a bug. Can you give an example of that?


reply via email to

[Prev in Thread] Current Thread [Next in Thread]