[dpdk-dev] [PATCH] pmd: Add generic support for TCP TSO (Transmit Segmentation Offload)

[miroslaw.walukiewicz at intel.com]

From: Miroslaw Walukiewicz <miroslaw.walukiewicz at intel.com>

Add new  PKT_TX_TCP_SEG flag
Add new fields in the tx offload fields indicating MSS and L4 len

Signed-off-by: Mirek Walukiewicz <miroslaw.walukiewicz at intel.com>
---
 lib/librte_mbuf/rte_mbuf.h |   23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index ddadc21..bcb09b9 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -114,6 +114,9 @@ extern "C" {
 /* Bit 51 - IEEE1588*/
 #define PKT_TX_IEEE1588_TMST (1ULL << 51) /**< TX IEEE1588 packet to timestamp. */
 
+/* Bit 49 - TCP transmit segmenation offload */
+#define PKT_TX_TCP_SEG (1ULL << 49) /**< TX TSO offload */
+ 
 /* Use final bit of flags to indicate a control mbuf */
 #define CTRL_MBUF_FLAG       (1ULL << 63) /**< Mbuf contains control data */
 
@@ -189,12 +192,22 @@ struct rte_mbuf {
 	struct rte_mbuf *next;    /**< Next segment of scattered packet. */
 
 	/* fields to support TX offloads */
-	union {
-		uint16_t l2_l3_len; /**< combined l2/l3 lengths as single var */
-		struct {
-			uint16_t l3_len:9;      /**< L3 (IP) Header Length. */
-			uint16_t l2_len:7;      /**< L2 (MAC) Header Length. */
+	/* two bytes - l2/l3 len for compatibility (endian issues)
+	 * two bytes - reseved for alignment
+	 * two bytes - l4 len (TCP/UDP) header len
+	 * two bytes - TCP tso segment size 
+ 	 */
+	struct {
+		union {
+			uint16_t l2_l3_len; /**< combined l2/l3 len */
+			struct {
+				uint16_t l3_len:9; /**< L3 (IP) Header */
+				uint16_t l2_len:7; /**< L2 (MAC) Header */
+			};
 		};
+		uint16_t reserved_tx_offload;
+		uint16_t l4_len;            /**< TCP/UDP header len */
+		uint16_t tso_segsz;         /**< TCP TSO segment size */
 	};
 } __rte_cache_aligned;