[PATCH] net/virtio: deduce IP length for Virtio TSO checksum

[PATCH] net/virtio: deduce IP length for Virtio TSO checksum

[Boleslav Stankevich]

The length of TSO payload could not fit into 16 bits provided by the
IPv4 total length and IPv6 payload length fields. Thus, deduce it
from the length of the packet.

Signed-off-by: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
---
 drivers/net/virtio/virtio_rxtx.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 2d0afd3302..e48ff3cca7 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -404,29 +404,36 @@ virtio_tso_fix_cksum(struct rte_mbuf *m)
 	if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
 			m->l4_len)) {
 		struct rte_ipv4_hdr *iph;
-		struct rte_ipv6_hdr *ip6h;
 		struct rte_tcp_hdr *th;
-		uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
+		uint16_t prev_cksum, new_cksum;
+		uint32_t ip_paylen;
 		uint32_t tmp;
 
 		iph = rte_pktmbuf_mtod_offset(m,
 					struct rte_ipv4_hdr *, m->l2_len);
 		th = RTE_PTR_ADD(iph, m->l3_len);
+
+		/*
+		 * Calculate IPv4 header checksum with current total length value
+		 * (whatever it is) to have correct checksum after update on edits
+		 * done by TSO.
+		 */
 		if ((iph->version_ihl >> 4) == 4) {
 			iph->hdr_checksum = 0;
 			iph->hdr_checksum = rte_ipv4_cksum(iph);
-			ip_len = iph->total_length;
-			ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
-				m->l3_len);
-		} else {
-			ip6h = (struct rte_ipv6_hdr *)iph;
-			ip_paylen = ip6h->payload_len;
 		}
 
+		/*
+		 * Do not use IPv4 total length and IPv6 payload length fields to get
+		 * TSO payload length since it could not fit into 16 bits.
+		 */
+		ip_paylen = rte_cpu_to_be_32(rte_pktmbuf_pkt_len(m) - m->l2_len -
+					m->l3_len);
+
 		/* calculate the new phdr checksum not including ip_paylen */
 		prev_cksum = th->cksum;
 		tmp = prev_cksum;
-		tmp += ip_paylen;
+		tmp += (ip_paylen & 0xffff) + (ip_paylen >> 16);
 		tmp = (tmp & 0xffff) + (tmp >> 16);
 		new_cksum = tmp;
 
-- 
2.30.2

[PATCH] net/virtio: deduce IP length for Virtio TSO checksum

[Boleslav Stankevich]

The length of TSO payload could not fit into 16 bits provided by the
IPv4 total length and IPv6 payload length fields. Thus, deduce it
from the length of the packet.

Signed-off-by: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
---
 drivers/net/virtio/virtio_rxtx.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 2d0afd3302..e48ff3cca7 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -404,29 +404,36 @@ virtio_tso_fix_cksum(struct rte_mbuf *m)
 	if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
 			m->l4_len)) {
 		struct rte_ipv4_hdr *iph;
-		struct rte_ipv6_hdr *ip6h;
 		struct rte_tcp_hdr *th;
-		uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
+		uint16_t prev_cksum, new_cksum;
+		uint32_t ip_paylen;
 		uint32_t tmp;
 
 		iph = rte_pktmbuf_mtod_offset(m,
 					struct rte_ipv4_hdr *, m->l2_len);
 		th = RTE_PTR_ADD(iph, m->l3_len);
+
+		/*
+		 * Calculate IPv4 header checksum with current total length value
+		 * (whatever it is) to have correct checksum after update on edits
+		 * done by TSO.
+		 */
 		if ((iph->version_ihl >> 4) == 4) {
 			iph->hdr_checksum = 0;
 			iph->hdr_checksum = rte_ipv4_cksum(iph);
-			ip_len = iph->total_length;
-			ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
-				m->l3_len);
-		} else {
-			ip6h = (struct rte_ipv6_hdr *)iph;
-			ip_paylen = ip6h->payload_len;
 		}
 
+		/*
+		 * Do not use IPv4 total length and IPv6 payload length fields to get
+		 * TSO payload length since it could not fit into 16 bits.
+		 */
+		ip_paylen = rte_cpu_to_be_32(rte_pktmbuf_pkt_len(m) - m->l2_len -
+					m->l3_len);
+
 		/* calculate the new phdr checksum not including ip_paylen */
 		prev_cksum = th->cksum;
 		tmp = prev_cksum;
-		tmp += ip_paylen;
+		tmp += (ip_paylen & 0xffff) + (ip_paylen >> 16);
 		tmp = (tmp & 0xffff) + (tmp >> 16);
 		new_cksum = tmp;
 
-- 
2.30.2

Re: [PATCH] net/virtio: deduce IP length for Virtio TSO checksum

[Maxime Coquelin]

Hi Boleslav,

On 2/16/23 13:35, Boleslav Stankevich wrote:
> The length of TSO payload could not fit into 16 bits provided by the
> IPv4 total length and IPv6 payload length fields. Thus, deduce it
> from the length of the packet.

My understanding is this is a fix.
If so could you please add the Fixes tag and Cc: stable@dpdk.org?

Thanks,
Maxime

> Signed-off-by: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>
> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> ---
>   drivers/net/virtio/virtio_rxtx.c | 25 ++++++++++++++++---------
>   1 file changed, 16 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index 2d0afd3302..e48ff3cca7 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -404,29 +404,36 @@ virtio_tso_fix_cksum(struct rte_mbuf *m)
>   	if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
>   			m->l4_len)) {
>   		struct rte_ipv4_hdr *iph;
> -		struct rte_ipv6_hdr *ip6h;
>   		struct rte_tcp_hdr *th;
> -		uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
> +		uint16_t prev_cksum, new_cksum;
> +		uint32_t ip_paylen;
>   		uint32_t tmp;
>   
>   		iph = rte_pktmbuf_mtod_offset(m,
>   					struct rte_ipv4_hdr *, m->l2_len);
>   		th = RTE_PTR_ADD(iph, m->l3_len);
> +
> +		/*
> +		 * Calculate IPv4 header checksum with current total length value
> +		 * (whatever it is) to have correct checksum after update on edits
> +		 * done by TSO.
> +		 */
>   		if ((iph->version_ihl >> 4) == 4) {
>   			iph->hdr_checksum = 0;
>   			iph->hdr_checksum = rte_ipv4_cksum(iph);
> -			ip_len = iph->total_length;
> -			ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
> -				m->l3_len);
> -		} else {
> -			ip6h = (struct rte_ipv6_hdr *)iph;
> -			ip_paylen = ip6h->payload_len;
>   		}
>   
> +		/*
> +		 * Do not use IPv4 total length and IPv6 payload length fields to get
> +		 * TSO payload length since it could not fit into 16 bits.
> +		 */
> +		ip_paylen = rte_cpu_to_be_32(rte_pktmbuf_pkt_len(m) - m->l2_len -
> +					m->l3_len);
> +
>   		/* calculate the new phdr checksum not including ip_paylen */
>   		prev_cksum = th->cksum;
>   		tmp = prev_cksum;
> -		tmp += ip_paylen;
> +		tmp += (ip_paylen & 0xffff) + (ip_paylen >> 16);
>   		tmp = (tmp & 0xffff) + (tmp >> 16);
>   		new_cksum = tmp;
>   

Re: [PATCH] net/virtio: deduce IP length for Virtio TSO checksum

[Boleslav Stankevich]

Hi, Maxime!

Yes, it is a fix and will add missing tags in v2.

Thanks,
Boleslav

On 02/03/2023 13:25, Maxime Coquelin wrote:
> Hi Boleslav,
>
> On 2/16/23 13:35, Boleslav Stankevich wrote:
>> The length of TSO payload could not fit into 16 bits provided by the
>> IPv4 total length and IPv6 payload length fields. Thus, deduce it
>> from the length of the packet.
>
> My understanding is this is a fix.
> If so could you please add the Fixes tag and Cc: stable@dpdk.org?
>
> Thanks,
> Maxime
>
>> Signed-off-by: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>
>> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
>> ---
>>   drivers/net/virtio/virtio_rxtx.c | 25 ++++++++++++++++---------
>>   1 file changed, 16 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/net/virtio/virtio_rxtx.c 
>> b/drivers/net/virtio/virtio_rxtx.c
>> index 2d0afd3302..e48ff3cca7 100644
>> --- a/drivers/net/virtio/virtio_rxtx.c
>> +++ b/drivers/net/virtio/virtio_rxtx.c
>> @@ -404,29 +404,36 @@ virtio_tso_fix_cksum(struct rte_mbuf *m)
>>       if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
>>               m->l4_len)) {
>>           struct rte_ipv4_hdr *iph;
>> -        struct rte_ipv6_hdr *ip6h;
>>           struct rte_tcp_hdr *th;
>> -        uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
>> +        uint16_t prev_cksum, new_cksum;
>> +        uint32_t ip_paylen;
>>           uint32_t tmp;
>>             iph = rte_pktmbuf_mtod_offset(m,
>>                       struct rte_ipv4_hdr *, m->l2_len);
>>           th = RTE_PTR_ADD(iph, m->l3_len);
>> +
>> +        /*
>> +         * Calculate IPv4 header checksum with current total length 
>> value
>> +         * (whatever it is) to have correct checksum after update on 
>> edits
>> +         * done by TSO.
>> +         */
>>           if ((iph->version_ihl >> 4) == 4) {
>>               iph->hdr_checksum = 0;
>>               iph->hdr_checksum = rte_ipv4_cksum(iph);
>> -            ip_len = iph->total_length;
>> -            ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
>> -                m->l3_len);
>> -        } else {
>> -            ip6h = (struct rte_ipv6_hdr *)iph;
>> -            ip_paylen = ip6h->payload_len;
>>           }
>>   +        /*
>> +         * Do not use IPv4 total length and IPv6 payload length 
>> fields to get
>> +         * TSO payload length since it could not fit into 16 bits.
>> +         */
>> +        ip_paylen = rte_cpu_to_be_32(rte_pktmbuf_pkt_len(m) - 
>> m->l2_len -
>> +                    m->l3_len);
>> +
>>           /* calculate the new phdr checksum not including ip_paylen */
>>           prev_cksum = th->cksum;
>>           tmp = prev_cksum;
>> -        tmp += ip_paylen;
>> +        tmp += (ip_paylen & 0xffff) + (ip_paylen >> 16);
>>           tmp = (tmp & 0xffff) + (tmp >> 16);
>>           new_cksum = tmp;
>

[PATCH v2] net/virtio: deduce IP length for Virtio TSO checksum

[Boleslav Stankevich]

The length of TSO payload could not fit into 16 bits provided by the
IPv4 total length and IPv6 payload length fields. Thus, deduce it
from the length of the packet.

Fixes: 696573046e9 ("net/virtio: support TSO")
Cc: stable@dpdk.org

Signed-off-by: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
---
 drivers/net/virtio/virtio_rxtx.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
index 2d0afd3302..e48ff3cca7 100644
--- a/drivers/net/virtio/virtio_rxtx.c
+++ b/drivers/net/virtio/virtio_rxtx.c
@@ -404,29 +404,36 @@ virtio_tso_fix_cksum(struct rte_mbuf *m)
 	if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
 			m->l4_len)) {
 		struct rte_ipv4_hdr *iph;
-		struct rte_ipv6_hdr *ip6h;
 		struct rte_tcp_hdr *th;
-		uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
+		uint16_t prev_cksum, new_cksum;
+		uint32_t ip_paylen;
 		uint32_t tmp;
 
 		iph = rte_pktmbuf_mtod_offset(m,
 					struct rte_ipv4_hdr *, m->l2_len);
 		th = RTE_PTR_ADD(iph, m->l3_len);
+
+		/*
+		 * Calculate IPv4 header checksum with current total length value
+		 * (whatever it is) to have correct checksum after update on edits
+		 * done by TSO.
+		 */
 		if ((iph->version_ihl >> 4) == 4) {
 			iph->hdr_checksum = 0;
 			iph->hdr_checksum = rte_ipv4_cksum(iph);
-			ip_len = iph->total_length;
-			ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
-				m->l3_len);
-		} else {
-			ip6h = (struct rte_ipv6_hdr *)iph;
-			ip_paylen = ip6h->payload_len;
 		}
 
+		/*
+		 * Do not use IPv4 total length and IPv6 payload length fields to get
+		 * TSO payload length since it could not fit into 16 bits.
+		 */
+		ip_paylen = rte_cpu_to_be_32(rte_pktmbuf_pkt_len(m) - m->l2_len -
+					m->l3_len);
+
 		/* calculate the new phdr checksum not including ip_paylen */
 		prev_cksum = th->cksum;
 		tmp = prev_cksum;
-		tmp += ip_paylen;
+		tmp += (ip_paylen & 0xffff) + (ip_paylen >> 16);
 		tmp = (tmp & 0xffff) + (tmp >> 16);
 		new_cksum = tmp;
 
-- 
2.30.2

v2:
* Extend Description with Fixes and CC tags.

Re: [PATCH v2] net/virtio: deduce IP length for Virtio TSO checksum

[Andrew Rybchenko]

Cc Maxime and Chenbo

On 3/3/23 14:19, Boleslav Stankevich wrote:
> The length of TSO payload could not fit into 16 bits provided by the
> IPv4 total length and IPv6 payload length fields. Thus, deduce it
> from the length of the packet.
> 
> Fixes: 696573046e9 ("net/virtio: support TSO")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>
> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> ---
>   drivers/net/virtio/virtio_rxtx.c | 25 ++++++++++++++++---------
>   1 file changed, 16 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index 2d0afd3302..e48ff3cca7 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -404,29 +404,36 @@ virtio_tso_fix_cksum(struct rte_mbuf *m)
>   	if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
>   			m->l4_len)) {
>   		struct rte_ipv4_hdr *iph;
> -		struct rte_ipv6_hdr *ip6h;
>   		struct rte_tcp_hdr *th;
> -		uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
> +		uint16_t prev_cksum, new_cksum;
> +		uint32_t ip_paylen;
>   		uint32_t tmp;
>   
>   		iph = rte_pktmbuf_mtod_offset(m,
>   					struct rte_ipv4_hdr *, m->l2_len);
>   		th = RTE_PTR_ADD(iph, m->l3_len);
> +
> +		/*
> +		 * Calculate IPv4 header checksum with current total length value
> +		 * (whatever it is) to have correct checksum after update on edits
> +		 * done by TSO.
> +		 */
>   		if ((iph->version_ihl >> 4) == 4) {
>   			iph->hdr_checksum = 0;
>   			iph->hdr_checksum = rte_ipv4_cksum(iph);
> -			ip_len = iph->total_length;
> -			ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
> -				m->l3_len);
> -		} else {
> -			ip6h = (struct rte_ipv6_hdr *)iph;
> -			ip_paylen = ip6h->payload_len;
>   		}
>   
> +		/*
> +		 * Do not use IPv4 total length and IPv6 payload length fields to get
> +		 * TSO payload length since it could not fit into 16 bits.
> +		 */
> +		ip_paylen = rte_cpu_to_be_32(rte_pktmbuf_pkt_len(m) - m->l2_len -
> +					m->l3_len);
> +
>   		/* calculate the new phdr checksum not including ip_paylen */
>   		prev_cksum = th->cksum;
>   		tmp = prev_cksum;
> -		tmp += ip_paylen;
> +		tmp += (ip_paylen & 0xffff) + (ip_paylen >> 16);
>   		tmp = (tmp & 0xffff) + (tmp >> 16);
>   		new_cksum = tmp;
>   

RE: [PATCH v2] net/virtio: deduce IP length for Virtio TSO checksum

[Xia, Chenbo]

Hi Boleslav,

The change seems good, but patchwork is complaining about lack of .mailmap change.

http://mails.dpdk.org/archives/test-report/2023-March/363061.html

Guess this is your first patch? So you need to add name and email in mailmap file.

Thanks,
Chenbo

> -----Original Message-----
> From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> Sent: Friday, March 3, 2023 11:14 PM
> To: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>; dev@dpdk.org
> Cc: stable@dpdk.org; Maxime Coquelin <maxime.coquelin@redhat.com>; Xia,
> Chenbo <chenbo.xia@intel.com>
> Subject: Re: [PATCH v2] net/virtio: deduce IP length for Virtio TSO
> checksum
> 
> Cc Maxime and Chenbo
> 
> On 3/3/23 14:19, Boleslav Stankevich wrote:
> > The length of TSO payload could not fit into 16 bits provided by the
> > IPv4 total length and IPv6 payload length fields. Thus, deduce it
> > from the length of the packet.
> >
> > Fixes: 696573046e9 ("net/virtio: support TSO")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>
> > Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> > ---
> >   drivers/net/virtio/virtio_rxtx.c | 25 ++++++++++++++++---------
> >   1 file changed, 16 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/net/virtio/virtio_rxtx.c
> b/drivers/net/virtio/virtio_rxtx.c
> > index 2d0afd3302..e48ff3cca7 100644
> > --- a/drivers/net/virtio/virtio_rxtx.c
> > +++ b/drivers/net/virtio/virtio_rxtx.c
> > @@ -404,29 +404,36 @@ virtio_tso_fix_cksum(struct rte_mbuf *m)
> >   	if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
> >   			m->l4_len)) {
> >   		struct rte_ipv4_hdr *iph;
> > -		struct rte_ipv6_hdr *ip6h;
> >   		struct rte_tcp_hdr *th;
> > -		uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
> > +		uint16_t prev_cksum, new_cksum;
> > +		uint32_t ip_paylen;
> >   		uint32_t tmp;
> >
> >   		iph = rte_pktmbuf_mtod_offset(m,
> >   					struct rte_ipv4_hdr *, m->l2_len);
> >   		th = RTE_PTR_ADD(iph, m->l3_len);
> > +
> > +		/*
> > +		 * Calculate IPv4 header checksum with current total length
> value
> > +		 * (whatever it is) to have correct checksum after update on
> edits
> > +		 * done by TSO.
> > +		 */
> >   		if ((iph->version_ihl >> 4) == 4) {
> >   			iph->hdr_checksum = 0;
> >   			iph->hdr_checksum = rte_ipv4_cksum(iph);
> > -			ip_len = iph->total_length;
> > -			ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
> > -				m->l3_len);
> > -		} else {
> > -			ip6h = (struct rte_ipv6_hdr *)iph;
> > -			ip_paylen = ip6h->payload_len;
> >   		}
> >
> > +		/*
> > +		 * Do not use IPv4 total length and IPv6 payload length fields
> to get
> > +		 * TSO payload length since it could not fit into 16 bits.
> > +		 */
> > +		ip_paylen = rte_cpu_to_be_32(rte_pktmbuf_pkt_len(m) - m-
> >l2_len -
> > +					m->l3_len);
> > +
> >   		/* calculate the new phdr checksum not including ip_paylen */
> >   		prev_cksum = th->cksum;
> >   		tmp = prev_cksum;
> > -		tmp += ip_paylen;
> > +		tmp += (ip_paylen & 0xffff) + (ip_paylen >> 16);
> >   		tmp = (tmp & 0xffff) + (tmp >> 16);
> >   		new_cksum = tmp;
> >

Re: [PATCH v2] net/virtio: deduce IP length for Virtio TSO checksum

[Maxime Coquelin]

On 3/6/23 07:17, Xia, Chenbo wrote:
> Hi Boleslav,
> 
> The change seems good, but patchwork is complaining about lack of .mailmap change.
> 
> http://mails.dpdk.org/archives/test-report/2023-March/363061.html
> 
> Guess this is your first patch? So you need to add name and email in mailmap file.


Thanks for the heads-up, I will update the mailmap when applying.
No need to submit a new revision.

Thanks,
Maxime

> Thanks,
> Chenbo
> 
>> -----Original Message-----
>> From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
>> Sent: Friday, March 3, 2023 11:14 PM
>> To: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>; dev@dpdk.org
>> Cc: stable@dpdk.org; Maxime Coquelin <maxime.coquelin@redhat.com>; Xia,
>> Chenbo <chenbo.xia@intel.com>
>> Subject: Re: [PATCH v2] net/virtio: deduce IP length for Virtio TSO
>> checksum
>>
>> Cc Maxime and Chenbo
>>
>> On 3/3/23 14:19, Boleslav Stankevich wrote:
>>> The length of TSO payload could not fit into 16 bits provided by the
>>> IPv4 total length and IPv6 payload length fields. Thus, deduce it
>>> from the length of the packet.
>>>
>>> Fixes: 696573046e9 ("net/virtio: support TSO")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>
>>> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
>>> ---
>>>    drivers/net/virtio/virtio_rxtx.c | 25 ++++++++++++++++---------
>>>    1 file changed, 16 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/net/virtio/virtio_rxtx.c
>> b/drivers/net/virtio/virtio_rxtx.c
>>> index 2d0afd3302..e48ff3cca7 100644
>>> --- a/drivers/net/virtio/virtio_rxtx.c
>>> +++ b/drivers/net/virtio/virtio_rxtx.c
>>> @@ -404,29 +404,36 @@ virtio_tso_fix_cksum(struct rte_mbuf *m)
>>>    	if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
>>>    			m->l4_len)) {
>>>    		struct rte_ipv4_hdr *iph;
>>> -		struct rte_ipv6_hdr *ip6h;
>>>    		struct rte_tcp_hdr *th;
>>> -		uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
>>> +		uint16_t prev_cksum, new_cksum;
>>> +		uint32_t ip_paylen;
>>>    		uint32_t tmp;
>>>
>>>    		iph = rte_pktmbuf_mtod_offset(m,
>>>    					struct rte_ipv4_hdr *, m->l2_len);
>>>    		th = RTE_PTR_ADD(iph, m->l3_len);
>>> +
>>> +		/*
>>> +		 * Calculate IPv4 header checksum with current total length
>> value
>>> +		 * (whatever it is) to have correct checksum after update on
>> edits
>>> +		 * done by TSO.
>>> +		 */
>>>    		if ((iph->version_ihl >> 4) == 4) {
>>>    			iph->hdr_checksum = 0;
>>>    			iph->hdr_checksum = rte_ipv4_cksum(iph);
>>> -			ip_len = iph->total_length;
>>> -			ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
>>> -				m->l3_len);
>>> -		} else {
>>> -			ip6h = (struct rte_ipv6_hdr *)iph;
>>> -			ip_paylen = ip6h->payload_len;
>>>    		}
>>>
>>> +		/*
>>> +		 * Do not use IPv4 total length and IPv6 payload length fields
>> to get
>>> +		 * TSO payload length since it could not fit into 16 bits.
>>> +		 */
>>> +		ip_paylen = rte_cpu_to_be_32(rte_pktmbuf_pkt_len(m) - m-
>>> l2_len -
>>> +					m->l3_len);
>>> +
>>>    		/* calculate the new phdr checksum not including ip_paylen */
>>>    		prev_cksum = th->cksum;
>>>    		tmp = prev_cksum;
>>> -		tmp += ip_paylen;
>>> +		tmp += (ip_paylen & 0xffff) + (ip_paylen >> 16);
>>>    		tmp = (tmp & 0xffff) + (tmp >> 16);
>>>    		new_cksum = tmp;
>>>
> 

Re: [PATCH v2] net/virtio: deduce IP length for Virtio TSO checksum

[Maxime Coquelin]

On 3/3/23 12:19, Boleslav Stankevich wrote:
> The length of TSO payload could not fit into 16 bits provided by the
> IPv4 total length and IPv6 payload length fields. Thus, deduce it
> from the length of the packet.
> 
> Fixes: 696573046e9 ("net/virtio: support TSO")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>
> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> ---
>   drivers/net/virtio/virtio_rxtx.c | 25 ++++++++++++++++---------
>   1 file changed, 16 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index 2d0afd3302..e48ff3cca7 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -404,29 +404,36 @@ virtio_tso_fix_cksum(struct rte_mbuf *m)
>   	if (likely(rte_pktmbuf_data_len(m) >= m->l2_len + m->l3_len +
>   			m->l4_len)) {
>   		struct rte_ipv4_hdr *iph;
> -		struct rte_ipv6_hdr *ip6h;
>   		struct rte_tcp_hdr *th;
> -		uint16_t prev_cksum, new_cksum, ip_len, ip_paylen;
> +		uint16_t prev_cksum, new_cksum;
> +		uint32_t ip_paylen;
>   		uint32_t tmp;
>   
>   		iph = rte_pktmbuf_mtod_offset(m,
>   					struct rte_ipv4_hdr *, m->l2_len);
>   		th = RTE_PTR_ADD(iph, m->l3_len);
> +
> +		/*
> +		 * Calculate IPv4 header checksum with current total length value
> +		 * (whatever it is) to have correct checksum after update on edits
> +		 * done by TSO.
> +		 */
>   		if ((iph->version_ihl >> 4) == 4) {
>   			iph->hdr_checksum = 0;
>   			iph->hdr_checksum = rte_ipv4_cksum(iph);
> -			ip_len = iph->total_length;
> -			ip_paylen = rte_cpu_to_be_16(rte_be_to_cpu_16(ip_len) -
> -				m->l3_len);
> -		} else {
> -			ip6h = (struct rte_ipv6_hdr *)iph;
> -			ip_paylen = ip6h->payload_len;
>   		}
>   
> +		/*
> +		 * Do not use IPv4 total length and IPv6 payload length fields to get
> +		 * TSO payload length since it could not fit into 16 bits.
> +		 */
> +		ip_paylen = rte_cpu_to_be_32(rte_pktmbuf_pkt_len(m) - m->l2_len -
> +					m->l3_len);
> +
>   		/* calculate the new phdr checksum not including ip_paylen */
>   		prev_cksum = th->cksum;
>   		tmp = prev_cksum;
> -		tmp += ip_paylen;
> +		tmp += (ip_paylen & 0xffff) + (ip_paylen >> 16);
>   		tmp = (tmp & 0xffff) + (tmp >> 16);
>   		new_cksum = tmp;
>   

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime

Re: [PATCH v2] net/virtio: deduce IP length for Virtio TSO checksum

[Maxime Coquelin]

On 3/3/23 12:19, Boleslav Stankevich wrote:
> The length of TSO payload could not fit into 16 bits provided by the
> IPv4 total length and IPv6 payload length fields. Thus, deduce it
> from the length of the packet.
> 
> Fixes: 696573046e9 ("net/virtio: support TSO")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Boleslav Stankevich <boleslav.stankevich@oktetlabs.ru>
> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> ---
>   drivers/net/virtio/virtio_rxtx.c | 25 ++++++++++++++++---------
>   1 file changed, 16 insertions(+), 9 deletions(-)
> 

Applied to dpdk-next-virtio/main.

Thanks,
Maxime