[dpdk-dev] [PATCH v2] net: prepare the outer ipv4 hdr for checksum

[dpdk-dev] [PATCH v2] net: prepare the outer ipv4 hdr for checksum

[Mohsin Kazmi]

Preparation the headers for the hardware offload
misses the outer ipv4 checksum offload.
It results in bad checksum computed by hardware NIC.

This patch fixes the issue by setting the outer ipv4
checksum field to 0.

Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
Cc: stable@dpdk.org

Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
Acked-by: Qi Zhang <qi.z.zhang@intel.com>
---

v2:
* Update the commit message with Fixes.
---
 lib/net/rte_net.h | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h
index 434435ffa2..e47365099e 100644
--- a/lib/net/rte_net.h
+++ b/lib/net/rte_net.h
@@ -128,8 +128,18 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m, uint64_t ol_flags)
 	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG)))
 		return 0;
 
-	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
+	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
 		inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
+		/*
+		 * prepare outer ipv4 header checksum by setting it to 0,
+		 * in order to be computed by hardware NICs.
+		 */
+		if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
+			ipv4_hdr = rte_pktmbuf_mtod_offset(m,
+					struct rte_ipv4_hdr *, m->outer_l2_len);
+			ipv4_hdr->hdr_checksum = 0;
+		}
+	}
 
 	/*
 	 * Check if headers are fragmented.
-- 
2.17.1

Re: [dpdk-dev] [PATCH v2] net: prepare the outer ipv4 hdr for checksum

[Olivier Matz]

Hi Mohsin,

Hope you are fine!
Please see my comments below.

On Wed, Jun 30, 2021 at 01:04:04PM +0200, Mohsin Kazmi wrote:
> Re: [PATCH v2] net: prepare the outer ipv4 hdr for checksum

I suggest to highlight that it this is the Intel-specific tx-prepare
function in the commit title. What about:

  net: fix Intel-specific Tx preparation for outer checksums

> Preparation the headers for the hardware offload
> misses the outer ipv4 checksum offload.
> It results in bad checksum computed by hardware NIC.
> 
> This patch fixes the issue by setting the outer ipv4
> checksum field to 0.
> 
> Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
> Acked-by: Qi Zhang <qi.z.zhang@intel.com>
> ---
> 
> v2:
> * Update the commit message with Fixes.
> ---
>  lib/net/rte_net.h | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h
> index 434435ffa2..e47365099e 100644
> --- a/lib/net/rte_net.h
> +++ b/lib/net/rte_net.h
> @@ -128,8 +128,18 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m, uint64_t ol_flags)
>  	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG)))
>  		return 0;

I think this test should be updated too with PKT_TX_OUTER_IP_CKSUM.

>  
> -	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
> +	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
>  		inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
> +		/*
> +		 * prepare outer ipv4 header checksum by setting it to 0,
> +		 * in order to be computed by hardware NICs.
> +		 */
> +		if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
> +			ipv4_hdr = rte_pktmbuf_mtod_offset(m,
> +					struct rte_ipv4_hdr *, m->outer_l2_len);
> +			ipv4_hdr->hdr_checksum = 0;
> +		}
> +	}

What about outer L4 checksum? Does it requires the same than inner?

>  
>  	/*
>  	 * Check if headers are fragmented.
> -- 
> 2.17.1
> 

Re: [dpdk-dev] [PATCH v2] net: prepare the outer ipv4 hdr for checksum

[Mohsin Kazmi]

Hi Olivier,

Thanks for the review.
Please find the comments inline below:

On Wed, Jun 30, 2021 at 3:09 PM Olivier Matz <olivier.matz@6wind.com> wrote:

> Hi Mohsin,
>
> Hope you are fine!
> Please see my comments below.
>
> On Wed, Jun 30, 2021 at 01:04:04PM +0200, Mohsin Kazmi wrote:
> > Re: [PATCH v2] net: prepare the outer ipv4 hdr for checksum
>
> I suggest to highlight that it this is the Intel-specific tx-prepare
> function in the commit title. What about:
>
  net: fix Intel-specific Tx preparation for outer checksums
>
> I'll update the commit title as suggested.

> Preparation the headers for the hardware offload
> > misses the outer ipv4 checksum offload.
> > It results in bad checksum computed by hardware NIC.
> >
> > This patch fixes the issue by setting the outer ipv4
> > checksum field to 0.
> >
> > Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
> > Acked-by: Qi Zhang <qi.z.zhang@intel.com>
> > ---
> >
> > v2:
> > * Update the commit message with Fixes.
> > ---
> >  lib/net/rte_net.h | 12 +++++++++++-
> >  1 file changed, 11 insertions(+), 1 deletion(-)
> >
> > diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h
> > index 434435ffa2..e47365099e 100644
> > --- a/lib/net/rte_net.h
> > +++ b/lib/net/rte_net.h
> > @@ -128,8 +128,18 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf
> *m, uint64_t ol_flags)
> >       if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK |
> PKT_TX_TCP_SEG)))
> >               return 0;
>
> I think this test should be updated too with PKT_TX_OUTER_IP_CKSUM.
>
Thanks. Yes, I'll update it too.

>
> >
> > -     if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
> > +     if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
> >               inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
> > +             /*
> > +              * prepare outer ipv4 header checksum by setting it to 0,
> > +              * in order to be computed by hardware NICs.
> > +              */
> > +             if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
> > +                     ipv4_hdr = rte_pktmbuf_mtod_offset(m,
> > +                                     struct rte_ipv4_hdr *,
> m->outer_l2_len);
> > +                     ipv4_hdr->hdr_checksum = 0;
> > +             }
> > +     }
>
> What about outer L4 checksum? Does it requires the same than inner?
>
I am using XL710 for my testing with i40e dpdk driver. AFAIK, It doesn't
support outer l4 checksum. I am not sure if other Intel NICs support it.


> >
> >       /*
> >        * Check if headers are fragmented.
> > --
> > 2.17.1
> >
>

[dpdk-dev] [PATCH v3] net: fix Intel-specific Prepare the outer ipv4 hdr for checksum

[Mohsin Kazmi]

Preparation the headers for the hardware offload
misses the outer ipv4 checksum offload.
It results in bad checksum computed by hardware NIC.

This patch fixes the issue by setting the outer ipv4
checksum field to 0.

Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
Cc: stable@dpdk.org

Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
Acked-by: Qi Zhang <qi.z.zhang@intel.com>
---
v3:
   * Update the conditional test with PKT_TX_OUTER_IP_CKSUM.
   * Update the commit title with "Intel-specific".

v2:
   * Update the commit message with Fixes.

 lib/net/rte_net.h | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h
index 434435ffa2..3f4c8c58b9 100644
--- a/lib/net/rte_net.h
+++ b/lib/net/rte_net.h
@@ -125,11 +125,22 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m, uint64_t ol_flags)
 	 * Mainly it is required to avoid fragmented headers check if
 	 * no offloads are requested.
 	 */
-	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG)))
+	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG |
+			  PKT_TX_OUTER_IP_CKSUM)))
 		return 0;
 
-	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
+	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
 		inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
+		/*
+		 * prepare outer ipv4 header checksum by setting it to 0,
+		 * in order to be computed by hardware NICs.
+		 */
+		if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
+			ipv4_hdr = rte_pktmbuf_mtod_offset(m,
+					struct rte_ipv4_hdr *, m->outer_l2_len);
+			ipv4_hdr->hdr_checksum = 0;
+		}
+	}
 
 	/*
 	 * Check if headers are fragmented.
-- 
2.17.1

Re: [dpdk-dev] [PATCH v2] net: prepare the outer ipv4 hdr for checksum

[Thomas Monjalon]

07/07/2021 11:14, Mohsin Kazmi:
> On Wed, Jun 30, 2021 at 3:09 PM Olivier Matz <olivier.matz@6wind.com> wrote:
> > > +     if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
> > >               inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
> > > +             /*
> > > +              * prepare outer ipv4 header checksum by setting it to 0,
> > > +              * in order to be computed by hardware NICs.
> > > +              */
> > > +             if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
> > > +                     ipv4_hdr = rte_pktmbuf_mtod_offset(m,
> > > +                                     struct rte_ipv4_hdr *,
> > m->outer_l2_len);
> > > +                     ipv4_hdr->hdr_checksum = 0;
> > > +             }
> > > +     }
> >
> > What about outer L4 checksum? Does it requires the same than inner?
> >
> I am using XL710 for my testing with i40e dpdk driver. AFAIK, It doesn't
> support outer l4 checksum. I am not sure if other Intel NICs support it.

This function is used by a lot of drivers.
Try git grep rte_net_intel_cksum_prepare

I think we need more reviews on the v3.
Given it is far from being a new bug, I suggest to wait the next release
in order to have more feedbacks.

Re: [dpdk-dev] [dpdk-stable] [PATCH v3] net: fix Intel-specific Prepare the outer ipv4 hdr for checksum

[Thomas Monjalon]

+Cc more people for reviews.

07/07/2021 11:40, Mohsin Kazmi:
> Preparation the headers for the hardware offload
> misses the outer ipv4 checksum offload.
> It results in bad checksum computed by hardware NIC.
> 
> This patch fixes the issue by setting the outer ipv4
> checksum field to 0.

nit: please write "IPv4" here and below.

> Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
> Acked-by: Qi Zhang <qi.z.zhang@intel.com>
[...]
> @@ -125,11 +125,22 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m, uint64_t ol_flags)
>  	 * Mainly it is required to avoid fragmented headers check if
>  	 * no offloads are requested.
>  	 */
> -	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG)))
> +	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG |
> +			  PKT_TX_OUTER_IP_CKSUM)))
>  		return 0;
>  
> -	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
> +	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
>  		inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
> +		/*
> +		 * prepare outer ipv4 header checksum by setting it to 0,
> +		 * in order to be computed by hardware NICs.
> +		 */
> +		if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
> +			ipv4_hdr = rte_pktmbuf_mtod_offset(m,
> +					struct rte_ipv4_hdr *, m->outer_l2_len);
> +			ipv4_hdr->hdr_checksum = 0;
> +		}
> +	}

Re: [dpdk-dev] [dpdk-stable] [PATCH v3] net: fix Intel-specific Prepare the outer ipv4 hdr for checksum

[Olivier Matz]

On Thu, Jul 22, 2021 at 09:56:25PM +0200, Thomas Monjalon wrote:
> +Cc more people for reviews.
> 
> 07/07/2021 11:40, Mohsin Kazmi:
> > Preparation the headers for the hardware offload

"of" is missing after Preparation?

> > misses the outer ipv4 checksum offload.
> > It results in bad checksum computed by hardware NIC.
> > 
> > This patch fixes the issue by setting the outer ipv4
> > checksum field to 0.
> 
> nit: please write "IPv4" here and below.
> 
> > Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
> > Acked-by: Qi Zhang <qi.z.zhang@intel.com>

Acked-by: Olivier Matz <olivier.matz@6wind.com>

Re: [dpdk-dev] [PATCH v3] net: fix Intel-specific Prepare the outer ipv4 hdr for checksum

[Andrew Rybchenko]

On 7/7/21 12:40 PM, Mohsin Kazmi wrote:
> Preparation the headers for the hardware offload
> misses the outer ipv4 checksum offload.
> It results in bad checksum computed by hardware NIC.
> 
> This patch fixes the issue by setting the outer ipv4
> checksum field to 0.
> 
> Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
> Acked-by: Qi Zhang <qi.z.zhang@intel.com>
> ---
> v3:
>     * Update the conditional test with PKT_TX_OUTER_IP_CKSUM.
>     * Update the commit title with "Intel-specific".
> 
> v2:
>     * Update the commit message with Fixes.
> 
>   lib/net/rte_net.h | 15 +++++++++++++--
>   1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h
> index 434435ffa2..3f4c8c58b9 100644
> --- a/lib/net/rte_net.h
> +++ b/lib/net/rte_net.h
> @@ -125,11 +125,22 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m, uint64_t ol_flags)
>   	 * Mainly it is required to avoid fragmented headers check if
>   	 * no offloads are requested.
>   	 */
> -	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG)))
> +	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG |
> +			  PKT_TX_OUTER_IP_CKSUM)))
>   		return 0;
>   
> -	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
> +	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
>   		inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
> +		/*
> +		 * prepare outer ipv4 header checksum by setting it to 0,
> +		 * in order to be computed by hardware NICs.
> +		 */
> +		if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
> +			ipv4_hdr = rte_pktmbuf_mtod_offset(m,
> +					struct rte_ipv4_hdr *, m->outer_l2_len);
> +			ipv4_hdr->hdr_checksum = 0;

Here we assume that the field is located in the first segment.
Unlikely but it still could be false. We must handle it properly.

> +		}
> +	}
>   
>   	/*
>   	 * Check if headers are fragmented.
> 

Re: [dpdk-dev] [PATCH v3] net: fix Intel-specific Prepare the outer ipv4 hdr for checksum

[Olivier Matz]

On Wed, Jul 28, 2021 at 06:46:53PM +0300, Andrew Rybchenko wrote:
> On 7/7/21 12:40 PM, Mohsin Kazmi wrote:
> > Preparation the headers for the hardware offload
> > misses the outer ipv4 checksum offload.
> > It results in bad checksum computed by hardware NIC.
> > 
> > This patch fixes the issue by setting the outer ipv4
> > checksum field to 0.
> > 
> > Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
> > Acked-by: Qi Zhang <qi.z.zhang@intel.com>
> > ---
> > v3:
> >     * Update the conditional test with PKT_TX_OUTER_IP_CKSUM.
> >     * Update the commit title with "Intel-specific".
> > 
> > v2:
> >     * Update the commit message with Fixes.
> > 
> >   lib/net/rte_net.h | 15 +++++++++++++--
> >   1 file changed, 13 insertions(+), 2 deletions(-)
> > 
> > diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h
> > index 434435ffa2..3f4c8c58b9 100644
> > --- a/lib/net/rte_net.h
> > +++ b/lib/net/rte_net.h
> > @@ -125,11 +125,22 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m, uint64_t ol_flags)
> >   	 * Mainly it is required to avoid fragmented headers check if
> >   	 * no offloads are requested.
> >   	 */
> > -	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG)))
> > +	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG |
> > +			  PKT_TX_OUTER_IP_CKSUM)))
> >   		return 0;
> > -	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
> > +	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
> >   		inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
> > +		/*
> > +		 * prepare outer ipv4 header checksum by setting it to 0,
> > +		 * in order to be computed by hardware NICs.
> > +		 */
> > +		if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
> > +			ipv4_hdr = rte_pktmbuf_mtod_offset(m,
> > +					struct rte_ipv4_hdr *, m->outer_l2_len);
> > +			ipv4_hdr->hdr_checksum = 0;
> 
> Here we assume that the field is located in the first segment.
> Unlikely but it still could be false. We must handle it properly.

This is specified in the API comment, so I think it has to be checked
by the caller.

> > +		}
> > +	}
> >   	/*
> >   	 * Check if headers are fragmented.
> > 
> 

Re: [dpdk-dev] [PATCH v3] net: fix Intel-specific Prepare the outer ipv4 hdr for checksum

[Andrew Rybchenko]

On 7/30/21 2:11 PM, Olivier Matz wrote:
> On Wed, Jul 28, 2021 at 06:46:53PM +0300, Andrew Rybchenko wrote:
>> On 7/7/21 12:40 PM, Mohsin Kazmi wrote:
>>> Preparation the headers for the hardware offload
>>> misses the outer ipv4 checksum offload.
>>> It results in bad checksum computed by hardware NIC.
>>>
>>> This patch fixes the issue by setting the outer ipv4
>>> checksum field to 0.
>>>
>>> Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
>>> Acked-by: Qi Zhang <qi.z.zhang@intel.com>
>>> ---
>>> v3:
>>>      * Update the conditional test with PKT_TX_OUTER_IP_CKSUM.
>>>      * Update the commit title with "Intel-specific".
>>>
>>> v2:
>>>      * Update the commit message with Fixes.
>>>
>>>    lib/net/rte_net.h | 15 +++++++++++++--
>>>    1 file changed, 13 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h
>>> index 434435ffa2..3f4c8c58b9 100644
>>> --- a/lib/net/rte_net.h
>>> +++ b/lib/net/rte_net.h
>>> @@ -125,11 +125,22 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m, uint64_t ol_flags)
>>>    	 * Mainly it is required to avoid fragmented headers check if
>>>    	 * no offloads are requested.
>>>    	 */
>>> -	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG)))
>>> +	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG |
>>> +			  PKT_TX_OUTER_IP_CKSUM)))
>>>    		return 0;
>>> -	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
>>> +	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
>>>    		inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
>>> +		/*
>>> +		 * prepare outer ipv4 header checksum by setting it to 0,
>>> +		 * in order to be computed by hardware NICs.
>>> +		 */
>>> +		if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
>>> +			ipv4_hdr = rte_pktmbuf_mtod_offset(m,
>>> +					struct rte_ipv4_hdr *, m->outer_l2_len);
>>> +			ipv4_hdr->hdr_checksum = 0;
>>
>> Here we assume that the field is located in the first segment.
>> Unlikely but it still could be false. We must handle it properly.
> 
> This is specified in the API comment, so I think it has to be checked
> by the caller.

If no, what's the point to spoil memory here if stricter check is
done few lines below.

>>> +		}
>>> +	}
>>>    	/*
>>>    	 * Check if headers are fragmented.
>>>
>>

Re: [dpdk-dev] [PATCH v2] net: prepare the outer ipv4 hdr for checksum

[Mohsin Kazmi]

Hi Thomas,

Thanks for the review.

I did the git grep rte_net_intel_cksum_prepare and git grep
PKT_TX_OUTER_UDP_CKSUM. Following are the two drivers that use the function
to prepare headers for checksum which also uses the outer_udp_checksum
offload within drivers.

1) Hisilicon hns3

2) Wangxun txgbe

1) has implemented its own version of functions to prepare for outer header
checksum. It may benefit/impact from the change.

The function "rte_net_intel_cksum_prepare" is intel specific and intel
cards do not support outer l4 checksum offload. DPDK may provide a generic
version of the same function which can be used in different drivers.

-br
Mohsin

On Thu, Jul 22, 2021 at 8:53 PM Thomas Monjalon <thomas@monjalon.net> wrote:

> 07/07/2021 11:14, Mohsin Kazmi:
> > On Wed, Jun 30, 2021 at 3:09 PM Olivier Matz <olivier.matz@6wind.com>
> wrote:
> > > > +     if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
> > > >               inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
> > > > +             /*
> > > > +              * prepare outer ipv4 header checksum by setting it to
> 0,
> > > > +              * in order to be computed by hardware NICs.
> > > > +              */
> > > > +             if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
> > > > +                     ipv4_hdr = rte_pktmbuf_mtod_offset(m,
> > > > +                                     struct rte_ipv4_hdr *,
> > > m->outer_l2_len);
> > > > +                     ipv4_hdr->hdr_checksum = 0;
> > > > +             }
> > > > +     }
> > >
> > > What about outer L4 checksum? Does it requires the same than inner?
> > >
> > I am using XL710 for my testing with i40e dpdk driver. AFAIK, It doesn't
> > support outer l4 checksum. I am not sure if other Intel NICs support it.
>
> This function is used by a lot of drivers.
> Try git grep rte_net_intel_cksum_prepare
>
> I think we need more reviews on the v3.
> Given it is far from being a new bug, I suggest to wait the next release
> in order to have more feedbacks.
>
>
>

Re: [dpdk-dev] [PATCH v3] net: fix Intel-specific Prepare the outer ipv4 hdr for checksum

[Mohsin Kazmi]

On Sat, Jul 31, 2021 at 1:49 PM Andrew Rybchenko <
andrew.rybchenko@oktetlabs.ru> wrote:

> On 7/30/21 2:11 PM, Olivier Matz wrote:
> > On Wed, Jul 28, 2021 at 06:46:53PM +0300, Andrew Rybchenko wrote:
> >> On 7/7/21 12:40 PM, Mohsin Kazmi wrote:
> >>> Preparation the headers for the hardware offload
> >>> misses the outer ipv4 checksum offload.
> >>> It results in bad checksum computed by hardware NIC.
> >>>
> >>> This patch fixes the issue by setting the outer ipv4
> >>> checksum field to 0.
> >>>
> >>> Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
> >>> Cc: stable@dpdk.org
> >>>
> >>> Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
> >>> Acked-by: Qi Zhang <qi.z.zhang@intel.com>
> >>> ---
> >>> v3:
> >>>      * Update the conditional test with PKT_TX_OUTER_IP_CKSUM.
> >>>      * Update the commit title with "Intel-specific".
> >>>
> >>> v2:
> >>>      * Update the commit message with Fixes.
> >>>
> >>>    lib/net/rte_net.h | 15 +++++++++++++--
> >>>    1 file changed, 13 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h
> >>> index 434435ffa2..3f4c8c58b9 100644
> >>> --- a/lib/net/rte_net.h
> >>> +++ b/lib/net/rte_net.h
> >>> @@ -125,11 +125,22 @@ rte_net_intel_cksum_flags_prepare(struct
> rte_mbuf *m, uint64_t ol_flags)
> >>>      * Mainly it is required to avoid fragmented headers check if
> >>>      * no offloads are requested.
> >>>      */
> >>> -   if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK |
> PKT_TX_TCP_SEG)))
> >>> +   if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK |
> PKT_TX_TCP_SEG |
> >>> +                     PKT_TX_OUTER_IP_CKSUM)))
> >>>             return 0;
> >>> -   if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
> >>> +   if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
> >>>             inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
> >>> +           /*
> >>> +            * prepare outer ipv4 header checksum by setting it to 0,
> >>> +            * in order to be computed by hardware NICs.
> >>> +            */
> >>> +           if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
> >>> +                   ipv4_hdr = rte_pktmbuf_mtod_offset(m,
> >>> +                                   struct rte_ipv4_hdr *,
> m->outer_l2_len);
> >>> +                   ipv4_hdr->hdr_checksum = 0;
> >>
> >> Here we assume that the field is located in the first segment.
> >> Unlikely but it still could be false. We must handle it properly.
> >
> > This is specified in the API comment, so I think it has to be checked
> > by the caller.
>
> If no, what's the point to spoil memory here if stricter check is
> done few lines below.
>
We have two possibilities:
1) take the whole block of above code after the strict check: Then strict
check will use m->outer_l2_len + m->outer_l3_len directly without any
condition and we will be on the mercy of drivers to initialize these to 0
if outer headers are not use. Drivers usually don't set the fields which
they are not interested in because of performance reasons as
setting these values per packet will cost them additional cycles.
2) Taking just PKT_TX_OUTER_IP_CKSUM conditional check after the strict
fragmented check: In that case, each packet will hit an extra conditional
check without getting benefit from it, again with a performance penalty.

I am more inclined towards solution 1. But I also welcome other
suggestions/comments.

>
> >>> +           }
> >>> +   }
> >>>     /*
> >>>      * Check if headers are fragmented.
> >>>
> >>
>
>

Re: [dpdk-dev] [PATCH v3] net: fix Intel-specific Prepare the outer ipv4 hdr for checksum

[Mohsin Kazmi]

Are we good with this patch with the current state? @Olivier: Any comments
on the above suggestions?

On Tue, Aug 3, 2021 at 1:49 PM Mohsin Kazmi <mohsin.kazmi14@gmail.com>
wrote:

>
>
> On Sat, Jul 31, 2021 at 1:49 PM Andrew Rybchenko <
> andrew.rybchenko@oktetlabs.ru> wrote:
>
>> On 7/30/21 2:11 PM, Olivier Matz wrote:
>> > On Wed, Jul 28, 2021 at 06:46:53PM +0300, Andrew Rybchenko wrote:
>> >> On 7/7/21 12:40 PM, Mohsin Kazmi wrote:
>> >>> Preparation the headers for the hardware offload
>> >>> misses the outer ipv4 checksum offload.
>> >>> It results in bad checksum computed by hardware NIC.
>> >>>
>> >>> This patch fixes the issue by setting the outer ipv4
>> >>> checksum field to 0.
>> >>>
>> >>> Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
>> >>> Cc: stable@dpdk.org
>> >>>
>> >>> Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
>> >>> Acked-by: Qi Zhang <qi.z.zhang@intel.com>
>> >>> ---
>> >>> v3:
>> >>>      * Update the conditional test with PKT_TX_OUTER_IP_CKSUM.
>> >>>      * Update the commit title with "Intel-specific".
>> >>>
>> >>> v2:
>> >>>      * Update the commit message with Fixes.
>> >>>
>> >>>    lib/net/rte_net.h | 15 +++++++++++++--
>> >>>    1 file changed, 13 insertions(+), 2 deletions(-)
>> >>>
>> >>> diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h
>> >>> index 434435ffa2..3f4c8c58b9 100644
>> >>> --- a/lib/net/rte_net.h
>> >>> +++ b/lib/net/rte_net.h
>> >>> @@ -125,11 +125,22 @@ rte_net_intel_cksum_flags_prepare(struct
>> rte_mbuf *m, uint64_t ol_flags)
>> >>>      * Mainly it is required to avoid fragmented headers check if
>> >>>      * no offloads are requested.
>> >>>      */
>> >>> -   if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK |
>> PKT_TX_TCP_SEG)))
>> >>> +   if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK |
>> PKT_TX_TCP_SEG |
>> >>> +                     PKT_TX_OUTER_IP_CKSUM)))
>> >>>             return 0;
>> >>> -   if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
>> >>> +   if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
>> >>>             inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
>> >>> +           /*
>> >>> +            * prepare outer ipv4 header checksum by setting it to 0,
>> >>> +            * in order to be computed by hardware NICs.
>> >>> +            */
>> >>> +           if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
>> >>> +                   ipv4_hdr = rte_pktmbuf_mtod_offset(m,
>> >>> +                                   struct rte_ipv4_hdr *,
>> m->outer_l2_len);
>> >>> +                   ipv4_hdr->hdr_checksum = 0;
>> >>
>> >> Here we assume that the field is located in the first segment.
>> >> Unlikely but it still could be false. We must handle it properly.
>> >
>> > This is specified in the API comment, so I think it has to be checked
>> > by the caller.
>>
>> If no, what's the point to spoil memory here if stricter check is
>> done few lines below.
>>
> We have two possibilities:
> 1) take the whole block of above code after the strict check: Then strict
> check will use m->outer_l2_len + m->outer_l3_len directly without any
> condition and we will be on the mercy of drivers to initialize these to 0
> if outer headers are not use. Drivers usually don't set the fields which
> they are not interested in because of performance reasons as
> setting these values per packet will cost them additional cycles.
> 2) Taking just PKT_TX_OUTER_IP_CKSUM conditional check after the strict
> fragmented check: In that case, each packet will hit an extra conditional
> check without getting benefit from it, again with a performance penalty.
>
> I am more inclined towards solution 1. But I also welcome other
> suggestions/comments.
>
>>
>> >>> +           }
>> >>> +   }
>> >>>     /*
>> >>>      * Check if headers are fragmented.
>> >>>
>> >>
>>
>>

[dpdk-dev] [PATCH v4] net: fix Intel-specific Prepare the outer IPv4 hdr for checksum

[Mohsin Kazmi]

Preparation of the headers for the hardware offload
misses the outer IPv4 checksum offload.
It results in bad checksum computed by hardware NIC.

This patch fixes the issue by setting the outer IPv4
checksum field to 0.

Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
Cc: stable@dpdk.org

Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
Acked-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
---
v4:
   * Update the commit message

v3:
   * Update the conditional test with PKT_TX_OUTER_IP_CKSUM.
   * Update the commit title with "Intel-specific".

v2:
   * Update the commit message with Fixes.

 lib/net/rte_net.h | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h
index 434435ffa2..42639bc154 100644
--- a/lib/net/rte_net.h
+++ b/lib/net/rte_net.h
@@ -125,11 +125,22 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m, uint64_t ol_flags)
 	 * Mainly it is required to avoid fragmented headers check if
 	 * no offloads are requested.
 	 */
-	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG)))
+	if (!(ol_flags & (PKT_TX_IP_CKSUM | PKT_TX_L4_MASK | PKT_TX_TCP_SEG |
+			  PKT_TX_OUTER_IP_CKSUM)))
 		return 0;
 
-	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6))
+	if (ol_flags & (PKT_TX_OUTER_IPV4 | PKT_TX_OUTER_IPV6)) {
 		inner_l3_offset += m->outer_l2_len + m->outer_l3_len;
+		/*
+		 * prepare outer IPv4 header checksum by setting it to 0,
+		 * in order to be computed by hardware NICs.
+		 */
+		if (ol_flags & PKT_TX_OUTER_IP_CKSUM) {
+			ipv4_hdr = rte_pktmbuf_mtod_offset(m,
+					struct rte_ipv4_hdr *, m->outer_l2_len);
+			ipv4_hdr->hdr_checksum = 0;
+		}
+	}
 
 	/*
 	 * Check if headers are fragmented.
-- 
2.17.1

Re: [dpdk-dev] [PATCH v4] net: fix Intel-specific Prepare the outer IPv4 hdr for checksum

[Ferruh Yigit]

On 9/7/2021 11:49 AM, Mohsin Kazmi wrote:
> Preparation of the headers for the hardware offload
> misses the outer IPv4 checksum offload.
> It results in bad checksum computed by hardware NIC.
> 
> This patch fixes the issue by setting the outer IPv4
> checksum field to 0.
> 
> Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
> Acked-by: Qi Zhang <qi.z.zhang@intel.com>
> Acked-by: Olivier Matz <olivier.matz@6wind.com>

<...>

> diff --git a/lib/net/rte_net.h b/lib/net/rte_net.h
> index 434435ffa2..42639bc154 100644
> --- a/lib/net/rte_net.h
> +++ b/lib/net/rte_net.h
> @@ -125,11 +125,22 @@ rte_net_intel_cksum_flags_prepare(struct rte_mbuf *m, uint64_t ol_flags)

Not directly related with this patch, but is the function
'rte_net_intel_cksum_flags_prepare()' really Intel specific?

I can see sfc & ena are also using this function, should we rename it?

Re: [dpdk-dev] [PATCH v4] net: fix Intel-specific Prepare the outer IPv4 hdr for checksum

[Ferruh Yigit]

On 9/7/2021 11:49 AM, Mohsin Kazmi wrote:
> Preparation of the headers for the hardware offload
> misses the outer IPv4 checksum offload.
> It results in bad checksum computed by hardware NIC.
> 
> This patch fixes the issue by setting the outer IPv4
> checksum field to 0.
> 
> Fixes: 4fb7e803eb1a ("ethdev: add Tx preparation")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Mohsin Kazmi <mohsin.kazmi14@gmail.com>
> Acked-by: Qi Zhang <qi.z.zhang@intel.com>
> Acked-by: Olivier Matz <olivier.matz@6wind.com>

Applied to dpdk-next-net/main, thanks.

Patch title updated as following while merging:
net: fix checksum offload for outer IPv4