[ PATCH v1 0/2] ibmveth gso fix.

[ PATCH v1 0/2] ibmveth gso fix.

[David Wilder]

The ibmveth driver is a virtual Ethernet driver used on IBM pSeries systems.
Gso packets can be sent between LPARS (virtual hosts) without segmentation,
by flagging gso packets using one of two methods depending on the firmware
version. Some gso packet may not be correctly identified by the receiver.
This patch-set corrects this issue.

Signed-off-by: David Wilder <dwilder@us.ibm.com>
Reviewed-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Reviewed-by: Cristobal Forno <cris.forno@ibm.com>
Reviewed-by: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com>

David Wilder (2):
  ibmveth: Switch order of ibmveth_helper calls.
  ibmveth: Identify ingress large send packets.

 drivers/net/ethernet/ibm/ibmveth.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

-- 
1.8.3.1

[ PATCH v1 1/2] ibmveth: Switch order of ibmveth_helper calls.

[David Wilder]

ibmveth_rx_csum_helper() must be called after ibmveth_rx_mss_helper()
as ibmveth_rx_csum_helper() may alter ip and tcp checksum values.

Signed-off-by: David Wilder <dwilder@us.ibm.com>
Reviewed-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Reviewed-by: Cristobal Forno <cris.forno@ibm.com>
Reviewed-by: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com>
---
 drivers/net/ethernet/ibm/ibmveth.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index c5c7326..3935a7e 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -1385,16 +1385,16 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
 			skb_put(skb, length);
 			skb->protocol = eth_type_trans(skb, netdev);
 
-			if (csum_good) {
-				skb->ip_summed = CHECKSUM_UNNECESSARY;
-				ibmveth_rx_csum_helper(skb, adapter);
-			}
-
 			if (length > netdev->mtu + ETH_HLEN) {
 				ibmveth_rx_mss_helper(skb, mss, lrg_pkt);
 				adapter->rx_large_packets++;
 			}
 
+			if (csum_good) {
+				skb->ip_summed = CHECKSUM_UNNECESSARY;
+				ibmveth_rx_csum_helper(skb, adapter);
+			}
+
 			napi_gro_receive(napi, skb);	/* send it up */
 
 			netdev->stats.rx_packets++;
-- 
1.8.3.1

Re: [ PATCH v1 1/2] ibmveth: Switch order of ibmveth_helper calls.

[Willem de Bruijn]

On Thu, Oct 8, 2020 at 3:06 PM David Wilder <dwilder@us.ibm.com> wrote:
>
> ibmveth_rx_csum_helper() must be called after ibmveth_rx_mss_helper()
> as ibmveth_rx_csum_helper() may alter ip and tcp checksum values.
>
> Signed-off-by: David Wilder <dwilder@us.ibm.com>
> Reviewed-by: Thomas Falcon <tlfalcon@linux.ibm.com>
> Reviewed-by: Cristobal Forno <cris.forno@ibm.com>
> Reviewed-by: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com>

Acked-by: Willem de Bruijn <willemb@google.com>

(for netdrv)

At first glance the two features sound independent, but this device
may pass mss information through the tcp checksum field. Hence that
must not get overwritten first.

"
        /* if mss is not set through Large Packet bit/mss in rx buffer,
         * expect that the mss will be written to the tcp header checksum.
         */
"

[ PATCH v1 2/2] ibmveth: Identify ingress large send packets.

[David Wilder]

Ingress large send packets are identified by either:
The IBMVETH_RXQ_LRG_PKT flag in the receive buffer
or with a -1 placed in the ip header checksum.
The method used depends on firmware version.

Signed-off-by: David Wilder <dwilder@us.ibm.com>
Reviewed-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Reviewed-by: Cristobal Forno <cris.forno@ibm.com>
Reviewed-by: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com>
---
 drivers/net/ethernet/ibm/ibmveth.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index 3935a7e..e357cbe 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -1349,6 +1349,7 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
 			int offset = ibmveth_rxq_frame_offset(adapter);
 			int csum_good = ibmveth_rxq_csum_good(adapter);
 			int lrg_pkt = ibmveth_rxq_large_packet(adapter);
+			__sum16 iph_check = 0;
 
 			skb = ibmveth_rxq_get_buffer(adapter);
 
@@ -1385,7 +1386,17 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
 			skb_put(skb, length);
 			skb->protocol = eth_type_trans(skb, netdev);
 
-			if (length > netdev->mtu + ETH_HLEN) {
+			/* PHYP without PLSO support places a -1 in the ip
+			 * checksum for large send frames.
+			 */
+			if (be16_to_cpu(skb->protocol) == ETH_P_IP) {
+				struct iphdr *iph = (struct iphdr *)skb->data;
+
+				iph_check = iph->check;
+			}
+
+			if ((length > netdev->mtu + ETH_HLEN) ||
+			    lrg_pkt || iph_check == 0xffff) {
 				ibmveth_rx_mss_helper(skb, mss, lrg_pkt);
 				adapter->rx_large_packets++;
 			}
-- 
1.8.3.1

Re: [ PATCH v1 2/2] ibmveth: Identify ingress large send packets.

[Willem de Bruijn]

On Thu, Oct 8, 2020 at 3:06 PM David Wilder <dwilder@us.ibm.com> wrote:
>
> Ingress large send packets are identified by either:
> The IBMVETH_RXQ_LRG_PKT flag in the receive buffer
> or with a -1 placed in the ip header checksum.
> The method used depends on firmware version.
>
> Signed-off-by: David Wilder <dwilder@us.ibm.com>
> Reviewed-by: Thomas Falcon <tlfalcon@linux.ibm.com>
> Reviewed-by: Cristobal Forno <cris.forno@ibm.com>
> Reviewed-by: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com>
> ---
>  drivers/net/ethernet/ibm/ibmveth.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
> index 3935a7e..e357cbe 100644
> --- a/drivers/net/ethernet/ibm/ibmveth.c
> +++ b/drivers/net/ethernet/ibm/ibmveth.c
> @@ -1349,6 +1349,7 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
>                         int offset = ibmveth_rxq_frame_offset(adapter);
>                         int csum_good = ibmveth_rxq_csum_good(adapter);
>                         int lrg_pkt = ibmveth_rxq_large_packet(adapter);
> +                       __sum16 iph_check = 0;
>
>                         skb = ibmveth_rxq_get_buffer(adapter);
>
> @@ -1385,7 +1386,17 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
>                         skb_put(skb, length);
>                         skb->protocol = eth_type_trans(skb, netdev);
>
> -                       if (length > netdev->mtu + ETH_HLEN) {
> +                       /* PHYP without PLSO support places a -1 in the ip
> +                        * checksum for large send frames.
> +                        */
> +                       if (be16_to_cpu(skb->protocol) == ETH_P_IP) {
> +                               struct iphdr *iph = (struct iphdr *)skb->data;
> +
> +                               iph_check = iph->check;

Check against truncated/bad packets.

Re: [ PATCH v1 2/2] ibmveth: Identify ingress large send packets.

[Willem de Bruijn]

On Sat, Oct 10, 2020 at 12:40 PM Willem de Bruijn
<willemdebruijn.kernel@gmail.com> wrote:
>
> On Thu, Oct 8, 2020 at 3:06 PM David Wilder <dwilder@us.ibm.com> wrote:
> >
> > Ingress large send packets are identified by either:
> > The IBMVETH_RXQ_LRG_PKT flag in the receive buffer
> > or with a -1 placed in the ip header checksum.
> > The method used depends on firmware version.
> >
> > Signed-off-by: David Wilder <dwilder@us.ibm.com>
> > Reviewed-by: Thomas Falcon <tlfalcon@linux.ibm.com>
> > Reviewed-by: Cristobal Forno <cris.forno@ibm.com>
> > Reviewed-by: Pradeep Satyanarayana <pradeeps@linux.vnet.ibm.com>
> > ---
> >  drivers/net/ethernet/ibm/ibmveth.c | 13 ++++++++++++-
> >  1 file changed, 12 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
> > index 3935a7e..e357cbe 100644
> > --- a/drivers/net/ethernet/ibm/ibmveth.c
> > +++ b/drivers/net/ethernet/ibm/ibmveth.c
> > @@ -1349,6 +1349,7 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
> >                         int offset = ibmveth_rxq_frame_offset(adapter);
> >                         int csum_good = ibmveth_rxq_csum_good(adapter);
> >                         int lrg_pkt = ibmveth_rxq_large_packet(adapter);
> > +                       __sum16 iph_check = 0;
> >
> >                         skb = ibmveth_rxq_get_buffer(adapter);
> >
> > @@ -1385,7 +1386,17 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
> >                         skb_put(skb, length);
> >                         skb->protocol = eth_type_trans(skb, netdev);
> >
> > -                       if (length > netdev->mtu + ETH_HLEN) {
> > +                       /* PHYP without PLSO support places a -1 in the ip
> > +                        * checksum for large send frames.
> > +                        */
> > +                       if (be16_to_cpu(skb->protocol) == ETH_P_IP) {
> > +                               struct iphdr *iph = (struct iphdr *)skb->data;
> > +
> > +                               iph_check = iph->check;
>
> Check against truncated/bad packets.

.. unless I missed context. Other code in this driver seems to peek in
the network and transport layer headers without additional geometry
and integrity checks, too.

Re: [ PATCH v1 2/2] ibmveth: Identify ingress large send packets.

[Jakub Kicinski]

On Sat, 10 Oct 2020 12:51:30 -0400 Willem de Bruijn wrote:
> > > @@ -1385,7 +1386,17 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
> > >                         skb_put(skb, length);
> > >                         skb->protocol = eth_type_trans(skb, netdev);
> > >
> > > -                       if (length > netdev->mtu + ETH_HLEN) {
> > > +                       /* PHYP without PLSO support places a -1 in the ip
> > > +                        * checksum for large send frames.
> > > +                        */
> > > +                       if (be16_to_cpu(skb->protocol) == ETH_P_IP) {

You can byteswap the constant, so its done at compilation time.

> > > +                               struct iphdr *iph = (struct iphdr *)skb->data;
> > > +
> > > +                               iph_check = iph->check;  
> >
> > Check against truncated/bad packets.  
> 
> .. unless I missed context. Other code in this driver seems to peek in
> the network and transport layer headers without additional geometry
> and integrity checks, too.

Good catch, even if we trust the hypervisor to only forward valid
frames this needs to be at least mentioned in the commit message.

Also please add Fixes tags to both patches.

RE: [ PATCH v1 2/2] ibmveth: Identify ingress large send packets.

[dwilder]

On 2020-10-11 11:31, Jakub Kicinski wrote:
> On Sat, 10 Oct 2020 12:51:30 -0400 Willem de Bruijn wrote:
>> > > @@ -1385,7 +1386,17 @@ static int ibmveth_poll(struct napi_struct *napi, int budget)
>> > >                         skb_put(skb, length);
>> > >                         skb->protocol = eth_type_trans(skb, netdev);
>> > >
>> > > -                       if (length > netdev->mtu + ETH_HLEN) {
>> > > +                       /* PHYP without PLSO support places a -1 in the ip
>> > > +                        * checksum for large send frames.
>> > > +                        */
>> > > +                       if (be16_to_cpu(skb->protocol) == ETH_P_IP) {
> 
> You can byteswap the constant, so its done at compilation time.

Thanks for the comments.

For V2 of patch I will change above to BE16_TO_CPU()

> 
>> > > +                               struct iphdr *iph = (struct iphdr *)skb->data;
>> > > +
>> > > +                               iph_check = iph->check;
>> >
>> > Check against truncated/bad packets.
>> 
>> .. unless I missed context. Other code in this driver seems to peek in
>> the network and transport layer headers without additional geometry
>> and integrity checks, too.
> 
> Good catch, even if we trust the hypervisor to only forward valid
> frames this needs to be at least mentioned in the commit message.
> 
> Also please add Fixes tags to both patches.

For V2: ( posting soon )
-Will add Fix tags
-update commit message re: validity of frames from Hypervisor.
-switch be16_to_cpu() to BE16_TO_CPU().

Thanks