When the 82575 is fed 802.1q packets, it chokes with
an error of the form:

igb 0000:08:00.1: partial checksum but proto=81

As the logic there was not smart enough to look into
the vlan header to pick out the encapsulated protocol.

There are times when we'd like to send these packets
out without having to configure a vlan on the interface.
Here we check for the vlan tag and allow the packet to
go out with the correct hardware checksum.

Thanks to Kand Ly <kand@riverbed.com> for discovering the
issue and the coming up with a solution.  This patch is
based upon his work.

Signed-off-by: Arthur Jones <ajones@riverbed.com>
---
 drivers/net/igb/igb_main.c |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index fddeece..99ba3a5 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -2778,7 +2778,17 @@ static inline bool igb_tx_csum_adv(struct igb_adapter *adapter,
 		tu_cmd |= (E1000_TXD_CMD_DEXT | E1000_ADVTXD_DTYP_CTXT);
 
 		if (skb->ip_summed == CHECKSUM_PARTIAL) {
-			switch (skb->protocol) {
+			__be16 protocol;
+
+			if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
+				const struct vlan_ethhdr *vhdr =
+					(const struct vlan_ethhdr *) skb->data;
+
+				protocol = vhdr->h_vlan_encapsulated_proto;
+			} else
+				protocol = skb->protocol;
+
+			switch (protocol) {
 			case __constant_htons(ETH_P_IP):
 				tu_cmd |= E1000_ADVTXD_TUCMD_IPV4;
 				if (ip_hdr(skb)->protocol == IPPROTO_TCP)
-- 
1.5.6.3
--

[ message continues ]

On Thu, 12 Mar 2009 13:27:24 -0700

That code in current igb driver (net-next-2.6) tree no longer has

Don't use __constant_htons() here, macro is smart enough to know when
--

[ message continues ]

Hi Stephen, ...


Ok, thanks, I'll test that one...

Arthur
--

[ message continues ]

On Thu, 12 Mar 2009 14:00:57 -0700

Actually, it is there just a little furthur down than I was looking
--

[ message continues ]

Hi Stephen, ...


The patch from linux-2.6 applies to net-next-2.6
with just a minor context fixup.  I think the issue
still exists in net-next-2.6, I'm compiling and testing
now...

Arthur
--

[ message continues ]

When the 82575 is fed 802.1q packets, it chokes with
an error of the form:

igb 0000:08:00.1: partial checksum but proto=81

As the logic there was not smart enough to look into
the vlan header to pick out the encapsulated protocol.

There are times when we'd like to send these packets
out without having to configure a vlan on the interface.
Here we check for the vlan tag and allow the packet to
go out with the correct hardware checksum.

Thanks to Kand Ly <kand@riverbed.com> for discovering the
issue and the coming up with a solution.  This patch is
based upon his work.

Macro fixups from Stephen Hemminger <shemminger@vyatta.com>

Signed-off-by: Arthur Jones <ajones@riverbed.com>
---
 drivers/net/igb/igb_main.c |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index 78558f8..e4ef1f6 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -3017,7 +3017,17 @@ static inline bool igb_tx_csum_adv(struct igb_adapter *adapter,
 		tu_cmd |= (E1000_TXD_CMD_DEXT | E1000_ADVTXD_DTYP_CTXT);
 
 		if (skb->ip_summed == CHECKSUM_PARTIAL) {
-			switch (skb->protocol) {
+			__be16 protocol;
+
+			if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
+				const struct vlan_ethhdr *vhdr =
+					(const struct vlan_ethhdr *) skb->data;
+
+				protocol = vhdr->h_vlan_encapsulated_proto;
+			} else
+				protocol = skb->protocol;
+
+			switch (protocol) {
 			case cpu_to_be16(ETH_P_IP):
 				tu_cmd |= E1000_ADVTXD_TUCMD_IPV4;
 				if (ip_hdr(skb)->protocol == IPPROTO_TCP)
-- 
1.5.6.3
--

[ message continues ]

I have added a few comments inline.

This should probably reference skb_mac_header(skb) instead of data in 

Thanks,

Alex
--

[ message continues ]

Hi Alexander, ...


Thanks, I'll fix these up and re-submit...

Arthur

--

[ message continues ]

I'm out of the office today, though, so testing
will have to wait until Monday -- I'll resend
after the patch is tested...

Arthur
--

[ message continues ]

When the 82575 is fed 802.1q packets, it chokes with
an error of the form:

igb 0000:08:00.1: partial checksum but proto=81

As the logic there was not smart enough to look into
the vlan header to pick out the encapsulated protocol.

There are times when we'd like to send these packets
out without having to configure a vlan on the interface.
Here we check for the vlan tag and allow the packet to
go out with the correct hardware checksum.

Thanks to Kand Ly <kand@riverbed.com> for discovering the
issue and the coming up with a solution.  This patch is
based upon his work.

Fixups from Stephen Hemminger <shemminger@vyatta.com> and
Alexander Duyck <alexander.h.duyck@intel.com>.

Signed-off-by: Arthur Jones <ajones@riverbed.com>
---
 drivers/net/igb/igb_main.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index 7124f59..26742dd 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -3030,7 +3030,18 @@ static inline bool igb_tx_csum_adv(struct igb_adapter *adapter,
 		tu_cmd |= (E1000_TXD_CMD_DEXT | E1000_ADVTXD_DTYP_CTXT);
 
 		if (skb->ip_summed == CHECKSUM_PARTIAL) {
-			switch (skb->protocol) {
+			__be16 protocol;
+
+			if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
+				const struct vlan_ethhdr *vhdr =
+					vlan_eth_hdr(skb);
+
+				protocol = vhdr->h_vlan_encapsulated_proto;
+			} else {
+				protocol = skb->protocol;
+			}
+
+			switch (protocol) {
 			case cpu_to_be16(ETH_P_IP):
 				tu_cmd |= E1000_ADVTXD_TUCMD_IPV4;
 				if (ip_hdr(skb)->protocol == IPPROTO_TCP)
-- 
1.5.6.3
--

[ message continues ]

From: Arthur Jones <ajones@riverbed.com>

Jeff, are you queueing this one up?
--

[ message continues ]