[PATCH v3] pcap: support MTU set

[Ido Goshen]

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit at xilinx.com>
> Sent: Monday, 30 May 2022 21:06
> To: Ido Goshen <Ido at cgstowernetworks.com>; ferruh.yigit at xilinx.com;
> stephen at networkplumber.org
> Cc: dev at dpdk.org; Tianli Lai <laitianli at tom.com>
> Subject: Re: [PATCH v3] pcap: support MTU set
> 
> On 5/30/2022 11:36 AM, Ido Goshen wrote:
> > Support rte_eth_dev_set_mtu by pcap vdevs Enforce mtu on rx/tx
> >

> 
> > +			rte_pktmbuf_free(mbuf);
> > +			continue;
> 
> Normally a PMD should not silently free a packet itself, it should return error and
> application will decide to free the packet or not.
> 

[idog] 
The doc say:
' The return value can be less than the value of the *tx_pkts* parameter when
   the transmit ring is full or has been filled up.'
Which is not the case
It will force failing all the burst's following packets too even if under MTU
I think in HW case oversized TX is dropped by the HW and not left to the app. 
Freeing might mimic it better, simpler and safer

I do miss incrementing the oerrors for that case