RE: [PATCH V2] app/testpmd: fix parameters order when calling rte_ether_addr_copy()

["Xu, Wei1" <wei1.xu@intel.com>]

Hi Ferruh,
Thanks for your explaining. 

It it by design, maybe a check and only rewrite the mac addresses when they are explicitly set?

Thanks,
Wei

-----Original Message-----
From: Yigit, Ferruh <ferruh.yigit@intel.com> 
Sent: Tuesday, November 16, 2021 3:00 AM
To: Xu, Wei1 <wei1.xu@intel.com>; Lu, Wenzhuo <wenzhuo.lu@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>; Iremonger, Bernard <bernard.iremonger@intel.com>; dev@dpdk.org
Cc: Zhang, Qi Z <qi.z.zhang@intel.com>
Subject: Re: [PATCH V2] app/testpmd: fix parameters order when calling rte_ether_addr_copy()

On 11/11/2021 2:29 AM, Xu, Wei1 wrote:
> Running in 'csum' mode, the 'from' and 'to' parameters are not in the 
> correct order when calling rte_ether_addr_copy() which means the 
> 'src/dst' mac addresses in the mbuf will be overwriten.
> 

Hi Wei,

Original code looks good. What are you trying to fix exactly?

API order is, 'rte_ether_addr_copy(from, to)'.

I assume your expectation is packet to keep original src & dst MAC address, but it is not working that way, dest addrs is written by user configured 'peer address'.

With your change for each packet, packet mac address written to testpmd configuration, which doesn't make sense.

> As a result, the packets will not be recognized and received by the 
> receiver(s).
> 
> Test CLI:
> ./app/dpdk-testpmd -n 1 -l 1-2 -a 09:00.0 -- -i --forward-mode=csum
> 
> Fixes: 10f4620(app/testpmd: modify mac in csum forwarding)
> 
> v2:
> 	- fixed indentation and long line warnings.
> 
> Signed-off-by: Wei Xu <wei1.xu@intel.com>
> ---
>   app/test-pmd/csumonly.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c index 
> 8526d9158a..08484fcda2 100644
> --- a/app/test-pmd/csumonly.c
> +++ b/app/test-pmd/csumonly.c
> @@ -872,10 +872,10 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
>   		 * and inner headers */
>   
>   		eth_hdr = rte_pktmbuf_mtod(m, struct rte_ether_hdr *);
> -		rte_ether_addr_copy(&peer_eth_addrs[fs->peer_addr],
> -				&eth_hdr->dst_addr);
> -		rte_ether_addr_copy(&ports[fs->tx_port].eth_addr,
> -				&eth_hdr->src_addr);
> +		rte_ether_addr_copy(&eth_hdr->dst_addr,
> +				&peer_eth_addrs[fs->peer_addr]);
> +		rte_ether_addr_copy(&eth_hdr->src_addr,
> +				&ports[fs->tx_port].eth_addr);
>   		parse_ethernet(eth_hdr, &info);
>   		l3_hdr = (char *)eth_hdr + info.l2_len;
>   
>