[ovs-dev] [ECNv2 5/5] tunnel: Mark ECN status on decapsulated tunnel packets.

[Justin Pettit]

In the kernel tunnel implementation, if a packet was marked as ECN CE on
the outer packet then we would carry this over to the inner packet on
decapsulation.  With the switch to flow based tunneling, this stopped
happening.  This commit reintroduces that behavior by using the set IP
header action.

Bug #15072

Signed-off-by: Justin Pettit <jpettit at nicira.com>
---
 ofproto/ofproto-dpif.c |   15 ++++++++++-----
 ofproto/tunnel.c       |    1 -
 tests/tunnel.at        |    4 ++--
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index e016e3b..93cf6a1 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -6301,11 +6301,16 @@ static bool
 tunnel_ecn_ok(struct action_xlate_ctx *ctx)
 {
     if (is_ip_any(&ctx->base_flow)
-        && (ctx->base_flow.tunnel.ip_tos & IP_ECN_MASK) == IP_ECN_CE
-        && (ctx->base_flow.nw_tos & IP_ECN_MASK) == IP_ECN_NOT_ECT) {
-        VLOG_WARN_RL(&rl, "dropping tunnel packet marked ECN CE but is not ECN"
-                     " capable");
-        return false;
+            && ((ctx->base_flow.tunnel.ip_tos & IP_ECN_MASK) == IP_ECN_CE)) {
+
+        if ((ctx->base_flow.nw_tos & IP_ECN_MASK) == IP_ECN_NOT_ECT) {
+            VLOG_WARN_RL(&rl, "dropping tunnel packet marked ECN CE"
+                         " but is not ECN capable");
+            return false;
+        } else {
+            /* Set the ECN CE value in the tunneled packet. */
+            ctx->flow.nw_tos |= IP_ECN_CE;
+        }
     }
 
     return true;
diff --git a/ofproto/tunnel.c b/ofproto/tunnel.c
index 8287937..13d821c 100644
--- a/ofproto/tunnel.c
+++ b/ofproto/tunnel.c
@@ -32,7 +32,6 @@
 
 /* XXX:
  *
- * Ability to generate actions on input for ECN
  * Ability to generate metadata for packet-outs
  * Disallow netdevs with names like "gre64_system" to prevent collisions. */
 
diff --git a/tests/tunnel.at b/tests/tunnel.at
index 97d245b..24af061 100644
--- a/tests/tunnel.at
+++ b/tests/tunnel.at
@@ -96,13 +96,13 @@ AT_CHECK([tail -1 stdout], [0],
 dnl Tunnel CE and encapsulated packet ECT(1)
 AT_CHECK([ovs-appctl ofproto/trace br0 'tunnel(tun_id=0x0,src=1.1.1.1,dst=2.2.2.2,tos=0x3,ttl=64,flags()),in_port(1),eth(src=50:54:00:00:00:05,dst=50:54:00:00:00:07),eth_type(0x0800),ipv4(src=192.168.0.1,dst=192.168.0.2,proto=6,tos=1,ttl=64,frag=no),tcp(src=8,dst=9)'], [0], [stdout])
 AT_CHECK([tail -1 stdout], [0],
-  [Datapath actions: 2
+  [Datapath actions: set(ipv4(src=192.168.0.1,dst=192.168.0.2,proto=6,tos=0x3,ttl=64,frag=no)),2
 ])
 
 dnl Tunnel CE and encapsulated packet ECT(2)
 AT_CHECK([ovs-appctl ofproto/trace br0 'tunnel(tun_id=0x0,src=1.1.1.1,dst=2.2.2.2,tos=0x3,ttl=64,flags()),in_port(1),eth(src=50:54:00:00:00:05,dst=50:54:00:00:00:07),eth_type(0x0800),ipv4(src=192.168.0.1,dst=192.168.0.2,proto=6,tos=2,ttl=64,frag=no),tcp(src=8,dst=9)'], [0], [stdout])
 AT_CHECK([tail -1 stdout], [0],
-  [Datapath actions: 2
+  [Datapath actions: set(ipv4(src=192.168.0.1,dst=192.168.0.2,proto=6,tos=0x3,ttl=64,frag=no)),2
 ])
 
 dnl Tunnel CE and encapsulated packet Non-ECT
-- 
1.7.5.4