Re: [lwip-devel] Problem with LWIP_ERROR in pbuf_header(..)

[address@hidden]

Fredrik Hederstierna wrote:
> > In the case you mention, shouldn't the first clause in the if statement
> > "if (p->tot_len < (IPH_HL(iphdr) * 4 + UDP_HLEN)"  protect us from the
> > assertion?  I.e. if the packet is short it should do that clause, but
> > then not the pbuf_header() call.
>
> But is it true that always  (p->tot_len == p->len)  here ?
> Maybe due to almost full memory  p->tot_len  is  larger than  p->len ?
> The ERROR is checking  p->len,  but if-statement checks  p->tot_len.

I think you are right: if the first pbuf is smaller than the headers, 
the assert may fail. We should check p->len: the lwIP code definively 
can't cope with headers spreaded over multiple pbufs.

Simon