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

[address@hidden]

To get a decent throughput you should definitvely increase some of the 
configuration options (mainly PBUF_POOL_SIZE, and MEM_SIZE).

The option that changes the length of the pbuf-pool buffers is not in 
your list, although that's the most interesting one for your problem 
(the assert): Can you tell us what PBUF_POOL_BUFSIZE is set to?

If you didn't configure that option an build with the default in opt.h, 
it should be big enough to get a full TCP segment (including data) in 
it, so enough also for all other protocols.

Simon


Fredrik Hederstierna wrote:
> > > That is if incomming UDP packet is too short, so the call to
> > > pbuf_header() will trig LWIP_ERROR?
> > > Isn't it better to just drop illegal-size packets instead of ASSERT?
> > > What if header and header length is corrupted?
> >
> > 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.
> >
> > Also, it's a good idea subscribe to lwip-devel to make sure you see
> > replies to your questions.  I've CC'd you as I noticed in this case that
> > you're not subscribed, but I don't always realise!
>
> About configure lwIP correct:
>
> How can we protect us from incoming packets with malformed headers or 
> too large headers?
>
> We config lwIP like this
>
>
> *#define* LWIP_RAW 0
> *#define* LWIP_DHCP 1
>
> *#define* IP_REASSEMBLY 0
>
> *#define* ARP_QUEUEING 1
>
> *#define* ARP_TABLE_SIZE 4
>
> *#define* PBUF_POOL_SIZE 10
>
> *#define* MEMP_NUM_PBUF 10
> *#define* MEMP_NUM_TCP_SEG 8
> *#define* MEMP_NUM_TCP_PCB_LISTEN 1
> *#define* MEMP_NUM_TCP_PCB 2
> *#define* MEMP_NUM_UDP_PCB 3
> *#define* MEMP_NUM_SYS_TIMEOUT 5
>
> *#define* MEM_SIZE 1500
>
>
> Should we use larger PBUF_POOL_SIZE ?  But how can we be sure that it 
> will work for all types of connections?
> Should we use larger HEAP size?
> Or if we get unexpected or malformed headers/packets?
>
> Best Regards
> /Fredrik
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