bnx2x: fix checksum validation

bnx2x driver incorrectly sets ip_summed to CHECKSUM_UNNECESSARY on
encapsulated segments. TCP stack happily accepts frames with bad
checksums, if they are inside a GRE or IPIP encapsulation.

Our understanding is that if no IP or L4 csum validation was done by the
hardware, we should leave ip_summed as is (CHECKSUM_NONE), since
hardware doesn't provide CHECKSUM_COMPLETE support in its cqe.

Then, if IP/L4 checksumming was done by the hardware, set
CHECKSUM_UNNECESSARY if no error was flagged.

Patch based on findings and analysis from Robert Evans

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Eilon Greenstein <eilong@broadcom.com>
Cc: Yaniv Rosner <yanivr@broadcom.com>
Cc: Merav Sicron <meravs@broadcom.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Robert Evans <evansr@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 21 insertions, 21 deletions

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
index e30e2a2f354c..7de824184979 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
@@ -747,21 +747,6 @@ struct bnx2x_fastpath {
 
 #define ETH_RX_ERROR_FALGS              ETH_FAST_PATH_RX_CQE_PHY_DECODE_ERR_FLG
 
-#define BNX2X_IP_CSUM_ERR(cqe) \
-                        (!((cqe)->fast_path_cqe.status_flags & \
-                           ETH_FAST_PATH_RX_CQE_IP_XSUM_NO_VALIDATION_FLG) && \
-                         ((cqe)->fast_path_cqe.type_error_flags & \
-                          ETH_FAST_PATH_RX_CQE_IP_BAD_XSUM_FLG))
-
-#define BNX2X_L4_CSUM_ERR(cqe) \
-                        (!((cqe)->fast_path_cqe.status_flags & \
-                           ETH_FAST_PATH_RX_CQE_L4_XSUM_NO_VALIDATION_FLG) && \
-                         ((cqe)->fast_path_cqe.type_error_flags & \
-                          ETH_FAST_PATH_RX_CQE_L4_BAD_XSUM_FLG))
-
-#define BNX2X_RX_CSUM_OK(cqe) \
-                        (!(BNX2X_L4_CSUM_ERR(cqe) || BNX2X_IP_CSUM_ERR(cqe)))
-
 #define BNX2X_PRS_FLAG_OVERETH_IPV4(flags) \
                                 (((le16_to_cpu(flags) & \
                                    PARSING_FLAGS_OVER_ETHERNET_PROTOCOL) >> \
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index ad0743bf4bde..cbc56f274e0c 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -617,6 +617,25 @@ static int bnx2x_alloc_rx_data(struct bnx2x *bp,
         return 0;
 }
 
+static void bnx2x_csum_validate(struct sk_buff *skb, union eth_rx_cqe *cqe,
+                                struct bnx2x_fastpath *fp)
+{
+        /* Do nothing if no IP/L4 csum validation was done */
+
+        if (cqe->fast_path_cqe.status_flags &
+            (ETH_FAST_PATH_RX_CQE_IP_XSUM_NO_VALIDATION_FLG |
+             ETH_FAST_PATH_RX_CQE_L4_XSUM_NO_VALIDATION_FLG))
+                return;
+
+        /* If both IP/L4 validation were done, check if an error was found. */
+
+        if (cqe->fast_path_cqe.type_error_flags &
+            (ETH_FAST_PATH_RX_CQE_IP_BAD_XSUM_FLG |
+             ETH_FAST_PATH_RX_CQE_L4_BAD_XSUM_FLG))
+                fp->eth_q_stats.hw_csum_err++;
+        else
+                skb->ip_summed = CHECKSUM_UNNECESSARY;
+}
 
 int bnx2x_rx_int(struct bnx2x_fastpath *fp, int budget)
 {
@@ -806,13 +825,9 @@ reuse_rx:
 
                 skb_checksum_none_assert(skb);
 
-                if (bp->dev->features & NETIF_F_RXCSUM) {
+                if (bp->dev->features & NETIF_F_RXCSUM)
+                        bnx2x_csum_validate(skb, cqe, fp);
 
-                        if (likely(BNX2X_RX_CSUM_OK(cqe)))
-                                skb->ip_summed = CHECKSUM_UNNECESSARY;
-                        else
-                                fp->eth_q_stats.hw_csum_err++;
-                }
 
                 skb_record_rx_queue(skb, fp->rx_queue);