Re: [lwip-devel] ethernetif.c HANDLE error

[Jonathan Larmour]

Pettinato, Jim wrote:
> Jonathan, Piero:
> 
> It is my understanding that NO checking is done on the return value of
> low_level_output()... it looks to me like the return value is passed
> back up the call chain and then eventually ignored by tcp_output. I
> think you could return ERR_END_OF_THE_WORLD_IS_AT_HAND without effect.
> ;)
> 
> Am I mistaken perhaps?

There are some situations where that happens, for example if an ARP request
caused a packet to be queued. But that seems legitimate since by the time
you know there's an error, you're no longer in the right context.

But in the normal course of things I can see the following calling path for
normal packets, each stage returning the error of the next:
ip_output -> ip_output_if -> netif->output which is etharp_output ->
etharp_send_ip -> netif->linkoutput which is low_level_output.

Jifl
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