[ovs-dev] [RFC] ipv6 tunneling: Fix for performance drop introduced by ipv6 tunnel support.

[Sugesh Chandran]

Adding a new flag to validate if the tunnel metadata is valid/not. This flag avoids
the need of resetting and validating the entire ipv4/ipv6 tunnel destination
address which caused a serious performance drop.

Signed-off-by: Sugesh Chandran <sugesh.chandran at intel.com>
---
 lib/match.c        | 2 ++
 lib/netdev-vport.c | 3 ++-
 lib/packets.h      | 8 ++++----
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/lib/match.c b/lib/match.c
index 95d34bc..79a561d 100644
--- a/lib/match.c
+++ b/lib/match.c
@@ -188,6 +188,7 @@ match_set_tun_dst_masked(struct match *match, ovs_be32 dst, ovs_be32 mask)
 {
     match->wc.masks.tunnel.ip_dst = mask;
     match->flow.tunnel.ip_dst = dst & mask;
+    match->flow.tunnel.is_tnl_valid = 1;
 }
 
 void
@@ -210,6 +211,7 @@ match_set_tun_ipv6_dst(struct match *match, const struct in6_addr *dst)
 {
     match->flow.tunnel.ipv6_dst = *dst;
     match->wc.masks.tunnel.ipv6_dst = in6addr_exact;
+    match->flow.tunnel.is_tnl_valid = 1;
 }
 
 void
diff --git a/lib/netdev-vport.c b/lib/netdev-vport.c
index 88f5022..1cf37d7 100644
--- a/lib/netdev-vport.c
+++ b/lib/netdev-vport.c
@@ -920,6 +920,7 @@ ip_extract_tnl_md(struct dp_packet *packet, struct flow_tnl *tnl,
 
         tnl->ip_src = ip_src;
         tnl->ip_dst = ip_dst;
+        tnl->is_tnl_valid = 1;
         tnl->ip_tos = ip->ip_tos;
         tnl->ip_ttl = ip->ip_ttl;
 
@@ -931,7 +932,7 @@ ip_extract_tnl_md(struct dp_packet *packet, struct flow_tnl *tnl,
         memcpy(tnl->ipv6_dst.s6_addr, ip6->ip6_dst.be16, sizeof ip6->ip6_dst);
         tnl->ip_tos = 0;
         tnl->ip_ttl = ip6->ip6_hlim;
-
+        tnl->is_tnl_valid = 1;
         *hlen += IPV6_HEADER_LEN;
 
     } else {
diff --git a/lib/packets.h b/lib/packets.h
index edf140b..06c1e19 100644
--- a/lib/packets.h
+++ b/lib/packets.h
@@ -37,6 +37,7 @@ struct ds;
 
 /* Tunnel information used in flow key and metadata. */
 struct flow_tnl {
+    bool is_tnl_valid;
     ovs_be32 ip_dst;
     struct in6_addr ipv6_dst;
     ovs_be32 ip_src;
@@ -49,7 +50,7 @@ struct flow_tnl {
     ovs_be16 tp_dst;
     ovs_be16 gbp_id;
     uint8_t  gbp_flags;
-    uint8_t  pad1[5];        /* Pad to 64 bits. */
+    uint8_t  pad1[1];        /* Pad to 64 bits. */
     struct tun_metadata metadata;
 };
 
@@ -79,7 +80,7 @@ static inline bool ipv6_addr_is_set(const struct in6_addr *addr);
 static inline bool
 flow_tnl_dst_is_set(const struct flow_tnl *tnl)
 {
-    return tnl->ip_dst || ipv6_addr_is_set(&tnl->ipv6_dst);
+    return tnl->is_tnl_valid;
 }
 
 struct in6_addr flow_tnl_dst(const struct flow_tnl *tnl);
@@ -157,8 +158,7 @@ pkt_metadata_init(struct pkt_metadata *md, odp_port_t port)
      * we can just zero out ip_dst and the rest of the data will never be
      * looked at. */
     memset(md, 0, offsetof(struct pkt_metadata, in_port));
-    md->tunnel.ip_dst = 0;
-    md->tunnel.ipv6_dst = in6addr_any;
+    md->tunnel.is_tnl_valid = 0;
 
     md->in_port.odp_port = port;
 }
-- 
1.9.1