tunnel: Generate datapath flows for tunneled packets dropped due to ECN.

Move the check for whether tunneled packets should be dropped due to
congestion encountered (CE) when the encapsulated packet is not ECN
capable (non-ECT).  This also adds some additional tests for ECN
handling on tunnel decapsulation.

Signed-off-by: Justin Pettit <jpettit@nicira.com>

2 files changed, 15 insertions, 9 deletions

diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index 5522b9ed..81118915 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -6272,6 +6272,20 @@ may_receive(const struct ofport_dpif *port, struct action_xlate_ctx *ctx)
     return true;
 }
 
+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;
+    }
+
+    return true;
+}
+
 static void
 do_xlate_actions(const struct ofpact *ofpacts, size_t ofpacts_len,
                  struct action_xlate_ctx *ctx)
@@ -6590,7 +6604,7 @@ xlate_actions(struct action_xlate_ctx *ctx,
 
         add_sflow_action(ctx);
 
-        if (!in_port || may_receive(in_port, ctx)) {
+        if (tunnel_ecn_ok(ctx) && (!in_port || may_receive(in_port, ctx))) {
             do_xlate_actions(ofpacts, ofpacts_len, ctx);
 
             /* We've let OFPP_NORMAL and the learning action look at the
diff --git a/ofproto/tunnel.c b/ofproto/tunnel.c
index afe7221d..82879376 100644
--- a/ofproto/tunnel.c
+++ b/ofproto/tunnel.c
@@ -197,14 +197,6 @@ tnl_port_receive(struct flow *flow)
         return NULL;
     }
 
-    if (is_ip_any(flow)
-        && ((flow->tunnel.ip_tos & IP_ECN_MASK) == IP_ECN_CE)
-        && (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 NULL;
-    }
-
     if (!VLOG_DROP_DBG(&dbg_rl)) {
         pre_flow_str = flow_to_string(flow);
     }