[dpdk-dev] [RFC] ethdev: add fragment attribute to IPv6 item

[Dekel Peled <dekelp@mellanox.com>]

Using the current implementation of DPDK, an application cannot
match on fragmented/non-fragmented IPv6 packets in a simple way.

In current implementation:
IPv6 header doesn't contain information regarding the packet
fragmentation.
Fragmented IPv6 packets contain a dedicated extension header, as
detailed in RFC [1], which is not yet supported in rte_flow.
Non-fragmented packets don't contain the fragment extension header.
For an application to match on non-fragmented IPv6 packets, the
current implementation doesn't provide a suitable solution.
Matching on the Next Header field is not sufficient, since additional
extension headers might be present in the same packet.
To match on fragmented IPv6 packets, the same difficulty exists.

Proposed update:
An additional value will be added to IPv6 header struct.
This value will contain the fragmentation attribute of the packet,
providing simple means for identification of fragmented and
non-fragmented packets.

This update changes ABI, and is proposed for the 20.11 LTS version.

[1] http://mails.dpdk.org/archives/dev/2020-March/160255.html

Signed-off-by: Dekel Peled <dekelp@mellanox.com>
---
 lib/librte_ethdev/rte_flow.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
index b0e4199..3bc8ce1 100644
--- a/lib/librte_ethdev/rte_flow.h
+++ b/lib/librte_ethdev/rte_flow.h
@@ -787,6 +787,8 @@ struct rte_flow_item_ipv4 {
  */
 struct rte_flow_item_ipv6 {
 	struct rte_ipv6_hdr hdr; /**< IPv6 header definition. */
+	uint32_t is_frag:1; /**< Is IPv6 packet fragmented/non-fragmented. */
+	uint32_t reserved:31; /**< Reserved, must be zero. */
 };
 
 /** Default mask for RTE_FLOW_ITEM_TYPE_IPV6. */
-- 
1.8.3.1