[Intel-wired-lan] [PATCH] ixgbe: Handle extended IPv6 headers in tx path

[Mark D Rustad]

Check for and handle IPv6 extended headers so that tx checksum
offload can be done. Thanks to Tom Herbert for noticing this
problem. Note that the goto back to process the final protocol
value can never result in a loop, because it cannot be yet
another extended header. Handling them in this manner avoids
adding further checks to the non-extended header hot path.

Reported-by: Tom Herbert <tom at herbertland.com>
Signed-off-by: Mark Rustad <mark.d.rustad at intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |   19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 1ffbe85eab7b..f5730ddbee96 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -7261,6 +7261,7 @@ static void ixgbe_tx_csum(struct ixgbe_ring *tx_ring,
 			}
 		}
 
+again:
 		switch (l4_hdr) {
 		case IPPROTO_TCP:
 			type_tucmd |= IXGBE_ADVTXD_TUCMD_L4T_TCP;
@@ -7277,7 +7278,23 @@ static void ixgbe_tx_csum(struct ixgbe_ring *tx_ring,
 					IXGBE_ADVTXD_L4LEN_SHIFT;
 			break;
 		default:
-			if (unlikely(net_ratelimit())) {
+			if (network_hdr.ipv4->version == 6 &&
+			    ipv6_ext_hdr(l4_hdr)) {
+				unsigned int offset = 0;
+				int ret;
+
+				ret = ipv6_find_hdr(skb, &offset, -1, NULL,
+						    NULL);
+				if (ret > 0) {
+					l4_hdr = ret;
+					goto again;
+				}
+				if (unlikely(net_ratelimit())) {
+					dev_warn(tx_ring->dev,
+						 "ipv6_find_hdr returned %d\n",
+						 ret);
+				}
+			} else if (unlikely(net_ratelimit())) {
 				dev_warn(tx_ring->dev,
 				 "partial checksum but l4 proto=%x!\n",
 				 l4_hdr);