[Click] Problem when running click with adding a new element

[yacine.djemaiel]

Hi Beyers,

Thank you very much for your help, i have added the element
after CheckIPHeader and the problem has been resolved.

Thanks again 
Yacine Djemaiel
 
> Hi Yacine,
>  
> Have a look at
http://www.pdos.lcs.mit.edu/click/doc/progman.html#Header%20Annotations
. The packet header annotations have to be set in order to use 
> p->ip_header and friends. CheckIPHeader element sets the IP
header annonations, so in your example put your element in the
config somewhere after CheckIPHeader in the config graph.
>  
> Alternatively you can use the following casts to gain a
pointer to the IP and TCP (same for UDP) header if the header
annotations haven't been set:
>  
> click_ip *ip = reinterpret_cast<click_ip *>(p->data());
> click_tcp *tcph = reinterpret_cast<click_tcp
*>(reinterpret_cast<unsigned char *>(ip) + (ip->ip_hl << 2));
>  
> Important, to use the above casts the packet should be an IP
packet with ethernet header removed, this can easily be
accomplished by using the Strip(14) element before your element.
>  
> Hope this helps.
>  
> Regards
>  
> Beyers Cronje
>  
> 
> ________________________________
> 
> From: click-bounces at amsterdam.lcs.mit.edu on behalf of
yacine.djemaiel
> Sent: Sat 10/16/2004 9:57 AM
> To: click
> Subject: [Click] Problem when running click with adding a
new element
> 
> 
> 
> Hi,
> I am trying to familiarize with click by building a new
> element. Following Mr. Eddie Kohler's thesis i have succeeded
> to add a new element that forward packets without handle them.
> In the next step, i have tried to manipulate the click_ip
> class so i call a new method in the pull method, the content
> of this method is :
> 
> Packet *
> NewElement::treat_packet(int port, Packet *p)
> {
> 
> const click_ip *iph = p->ip_header();
> if (iph->ip_p != IPPROTO_TCP) click_chatter("Non TCP
> trafic");
> else return p;
> return p;
> }
> 
> When running click with the following config, i obtain this
> error message :
> Segmentation fault
> 
> config used : FromDevice(eth0)->NewElement->Discard;
> 
> i have added a Queue, before the NewElement but i have
> received the same error.
> 
> Thanks in advance,
> 
> Yacine Djemail
> 
> 
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