[dpdk-dev] Packet crafting....

sabu kurian sabu2kurian at gmail.com
Fri Mar 14 13:04:09 CET 2014

Ok thanks a lot Richardson. I got your point. What confused me was that the
size of MBUF and the maximum size are all passed to
'rte_mempool_create' . rte_pktmbuf_alloc
has only one parameter , a pointer to the mbuf pool.  I got it cleared now.
Thanks for your valuable time. Can you answer my other question ?... like I
get a segmentation fault when I try to print the ether_type for a packet.
This is the print statement:  printf("\n Type is %" PRIu16 , *((uint16_t


On Fri, Mar 14, 2014 at 5:19 PM, Richardson, Bruce <
bruce.richardson at intel.com> wrote:

> > From: sabu kurian [mailto:sabu2kurian at gmail.com]
> > Sent: Friday, March 14, 2014 11:38 AM
> > To: Richardson, Bruce
> > Cc: dev at dpdk.org
> > Subject: Re: [dpdk-dev] Packet crafting....
> >
> > Thanks on the reply Richardson. You did mention something like "Don't
> forget that when you get the mbuf from
> > rte_pktmbuf_alloc, you also need to set the length value to the
> appropriate size." .
> >
> > Like I'm allocating the mbuf using rte_mbuf . The rte_mempool_create has
> already set the maximum packet size
> > for a mbuf and the number of mbuf's and all. So do I really need to
> use rte_pktmbuf_alloc ?
> How are you getting an mbuf from the pool, if not using rte_pktmbuf_alloc?
> When you have an mbuf, that buffer has a maximum size, generally around
> 2k. However, the packet inside that buffer is generally smaller than the
> overall buffer size and you must configure that size, otherwise the PMD,
> and therefore the NIC, has no idea how much data out of that 2k buffer
> needs to be transmitted.

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