[PATCH] net: add bit fields to IPv6 header definition

[Gregory Etelson]

DPDK IPv6 header definition combined the `version`, `traffic class`
and `flow label` header fields into a single 32 bits structure member
`vtc_flow`.

The patch expands IPv6 header definition with dedicated structure
members for the `version`, `traffic class` and `flow label` fields.
The patch also preserves existing `vtc_flow` structure member for
backward compatibility.

Signed-off-by: Gregory Etelson <getelson at nvidia.com>
---
 lib/net/rte_ip.h | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/lib/net/rte_ip.h b/lib/net/rte_ip.h
index 0d103d4127..26e78a6624 100644
--- a/lib/net/rte_ip.h
+++ b/lib/net/rte_ip.h
@@ -524,7 +524,21 @@ rte_ipv4_udptcp_cksum_mbuf_verify(const struct rte_mbuf *m,
  * IPv6 Header
  */
 struct rte_ipv6_hdr {
-	rte_be32_t vtc_flow;	/**< IP version, traffic class & flow label. */
+	__extension__
+	union {
+		rte_be32_t vtc_flow;        /**< IP version, traffic class & flow label. */
+		struct {
+#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
+			uint32_t flow_label:24; /**< flow label */
+			uint32_t tc:4;     /**< traffic class */
+			uint32_t version:4; /**< version */
+#elif RTE_BYTE_ORDER == RTE_BIG_ENDIAN
+			uint8_t version:4; /**< version */
+			uint8_t tc:4;     /**< traffic class */
+			uint32_t flow_label:24; /**< flow label */
+#endif
+		};
+	};
 	rte_be16_t payload_len;	/**< IP payload size, including ext. headers */
 	uint8_t  proto;		/**< Protocol, next header. */
 	uint8_t  hop_limits;	/**< Hop limits. */
-- 
2.43.0