[dpdk-dev] [PATCH v3] mbuf: outer offsets are undefined for non-tunnel packets

[Ivan Malov]

The default policy for offload-specific fields is that
they are undefined unless the corresponding offloads are
requested in mbuf ol_flags. This is also the case for outer
L2 and L3 length fields which must not be assumed to contain
zeros for non-tunnel packets. The patch clarifies this behaviour
in the comments and also adds appropriate checks to the PMDs which
do not check any tunnel-related offloads before using the said fields.

Signed-off-by: Ivan Malov <ivan.malov at oktetlabs.ru>
Reviewed-by: Andrew Rybchenko <arybchenko at solarflare.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev at intel.com>
---
 drivers/net/bnxt/bnxt_txr.c    |  6 ++++--
 drivers/net/fm10k/fm10k_rxtx.c |  5 +++--
 drivers/net/i40e/i40e_rxtx.c   | 12 +++---------
 drivers/net/iavf/iavf_rxtx.c   |  3 ---
 drivers/net/ice/ice_rxtx.c     | 12 +++---------
 lib/librte_mbuf/rte_mbuf.h     | 13 ++++++++++++-
 6 files changed, 25 insertions(+), 26 deletions(-)

diff --git a/drivers/net/bnxt/bnxt_txr.c b/drivers/net/bnxt/bnxt_txr.c
index 124186e..c71e6f1 100644
--- a/drivers/net/bnxt/bnxt_txr.c
+++ b/drivers/net/bnxt/bnxt_txr.c
@@ -235,8 +235,10 @@ static uint16_t bnxt_start_xmit(struct rte_mbuf *tx_pkt,
 			txbd1->lflags |= TX_BD_LONG_LFLAGS_LSO |
 					 TX_BD_LONG_LFLAGS_T_IPID;
 			hdr_size = tx_pkt->l2_len + tx_pkt->l3_len +
-					tx_pkt->l4_len + tx_pkt->outer_l2_len +
-					tx_pkt->outer_l3_len;
+					tx_pkt->l4_len;
+			hdr_size += (tx_pkt->ol_flags & PKT_TX_TUNNEL_MASK) ?
+				    tx_pkt->outer_l2_len +
+				    tx_pkt->outer_l3_len : 0;
 			/* The hdr_size is multiple of 16bit units not 8bit.
 			 * Hence divide by 2.
 			 */
diff --git a/drivers/net/fm10k/fm10k_rxtx.c b/drivers/net/fm10k/fm10k_rxtx.c
index 2f4dad0..5c31121 100644
--- a/drivers/net/fm10k/fm10k_rxtx.c
+++ b/drivers/net/fm10k/fm10k_rxtx.c
@@ -619,8 +619,9 @@ static inline void tx_xmit_pkt(struct fm10k_tx_queue *q, struct rte_mbuf *mb)
 			rte_cpu_to_le_16(rte_pktmbuf_data_len(mb));
 
 	if (mb->ol_flags & PKT_TX_TCP_SEG) {
-		hdrlen = mb->outer_l2_len + mb->outer_l3_len + mb->l2_len +
-			mb->l3_len + mb->l4_len;
+		hdrlen = mb->l2_len + mb->l3_len + mb->l4_len;
+		hdrlen += (mb->ol_flags & PKT_TX_TUNNEL_MASK) ?
+			  mb->outer_l2_len + mb->outer_l3_len : 0;
 		if (q->hw_ring[q->next_free].flags & FM10K_TXD_FLAG_FTAG)
 			hdrlen += sizeof(struct fm10k_ftag);
 
diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c
index 85c44f5..34aa6c8 100644
--- a/drivers/net/i40e/i40e_rxtx.c
+++ b/drivers/net/i40e/i40e_rxtx.c
@@ -981,15 +981,9 @@
 		return ctx_desc;
 	}
 
-	/**
-	 * in case of non tunneling packet, the outer_l2_len and
-	 * outer_l3_len must be 0.
-	 */
-	hdr_len = tx_offload.outer_l2_len +
-		tx_offload.outer_l3_len +
-		tx_offload.l2_len +
-		tx_offload.l3_len +
-		tx_offload.l4_len;
+	hdr_len = tx_offload.l2_len + tx_offload.l3_len + tx_offload.l4_len;
+	hdr_len += (mbuf->ol_flags & PKT_TX_TUNNEL_MASK) ?
+		   tx_offload.outer_l2_len + tx_offload.outer_l3_len : 0;
 
 	cd_cmd = I40E_TX_CTX_DESC_TSO;
 	cd_tso_len = mbuf->pkt_len - hdr_len;
diff --git a/drivers/net/iavf/iavf_rxtx.c b/drivers/net/iavf/iavf_rxtx.c
index 0be3ede..2d37c17 100644
--- a/drivers/net/iavf/iavf_rxtx.c
+++ b/drivers/net/iavf/iavf_rxtx.c
@@ -1449,9 +1449,6 @@
 		return ctx_desc;
 	}
 
-	/* in case of non tunneling packet, the outer_l2_len and
-	 * outer_l3_len must be 0.
-	 */
 	hdr_len = tx_offload.l2_len +
 		  tx_offload.l3_len +
 		  tx_offload.l4_len;
diff --git a/drivers/net/ice/ice_rxtx.c b/drivers/net/ice/ice_rxtx.c
index 0fb3e7f..035ed84 100644
--- a/drivers/net/ice/ice_rxtx.c
+++ b/drivers/net/ice/ice_rxtx.c
@@ -1940,15 +1940,9 @@
 		return ctx_desc;
 	}
 
-	/**
-	 * in case of non tunneling packet, the outer_l2_len and
-	 * outer_l3_len must be 0.
-	 */
-	hdr_len = tx_offload.outer_l2_len +
-		  tx_offload.outer_l3_len +
-		  tx_offload.l2_len +
-		  tx_offload.l3_len +
-		  tx_offload.l4_len;
+	hdr_len = tx_offload.l2_len + tx_offload.l3_len + tx_offload.l4_len;
+	hdr_len += (mbuf->ol_flags & PKT_TX_TUNNEL_MASK) ?
+		   tx_offload.outer_l2_len + tx_offload.outer_l3_len : 0;
 
 	cd_cmd = ICE_TX_CTX_DESC_TSO;
 	cd_tso_len = mbuf->pkt_len - hdr_len;
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 0d9fef0..ddb562f 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -702,7 +702,18 @@ struct rte_mbuf {
 			uint64_t tso_segsz:RTE_MBUF_TSO_SEGSZ_BITS;
 			/**< TCP TSO segment size */
 
-			/* fields for TX offloading of tunnels */
+			/*
+			 * Fields for Tx offloading of tunnels.
+			 * These are undefined for packets which don't request
+			 * any tunnel offloads (outer IP or UDP checksum,
+			 * tunnel TSO).
+			 *
+			 * PMDs should not use these fields unconditionally
+			 * when calculating offsets.
+			 *
+			 * Applications are expected to set appropriate tunnel
+			 * offload flags when they fill in these fields.
+			 */
 			uint64_t outer_l3_len:RTE_MBUF_OUTL3_LEN_BITS;
 			/**< Outer L3 (IP) Hdr Length. */
 			uint64_t outer_l2_len:RTE_MBUF_OUTL2_LEN_BITS;
-- 
1.8.3.1