[ovs-dev,v4] xlate: Use OVS_CT_ATTR_EVENTMASK.

diff --git a/build-aux/extract-odp-netlink-h b/build-aux/extract-odp-netlink-h
index 907a70a..7fb6ce8 100755
--- a/build-aux/extract-odp-netlink-h
+++ b/build-aux/extract-odp-netlink-h
@@ -19,6 +19,8 @@  $i\
 #ifdef _WIN32\
 #include "OvsDpInterfaceExt.h"\
 #include "OvsDpInterfaceCtExt.h"\
+#else\
+#include "linux/netfilter/nf_conntrack_common.h"\
 #endif\
 
 # Use OVS's own struct eth_addr instead of a 6-byte char array.
diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
index d8c6a7c..ab5eef8 100644
--- a/ofproto/ofproto-dpif-xlate.c
+++ b/ofproto/ofproto-dpif-xlate.c
@@ -5351,6 +5351,12 @@  compose_conntrack_action(struct xlate_ctx *ctx, struct ofpact_conntrack *ofc)
     if (ofc->flags & NX_CT_F_COMMIT) {
         nl_msg_put_flag(ctx->odp_actions, ofc->flags & NX_CT_F_FORCE ?
                         OVS_CT_ATTR_FORCE_COMMIT : OVS_CT_ATTR_COMMIT);
+        if (ctx->xbridge->support.ct_eventmask) {
+            nl_msg_put_u32(ctx->odp_actions, OVS_CT_ATTR_EVENTMASK,
+                           1 << IPCT_NEW | 1 << IPCT_RELATED |
+                           1 << IPCT_DESTROY | 1 << IPCT_MARK |
+                           1 << IPCT_LABEL);
+        }
     }
     nl_msg_put_u16(ctx->odp_actions, OVS_CT_ATTR_ZONE, zone);
     put_ct_mark(&ctx->xin->flow, ctx->odp_actions, ctx->wc);
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index c73c273..23a8575 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -1241,6 +1241,67 @@  check_clone(struct dpif_backer *backer)
     return !error;
 }
 
+/* Tests whether 'backer''s datapath supports the OVS_CT_ATTR_EVENTMASK
+ * attribute in OVS_ACTION_ATTR_CT. */
+static bool
+check_ct_eventmask(struct dpif_backer *backer)
+{
+    struct dpif_execute execute;
+    struct dp_packet packet;
+    struct ofpbuf actions;
+    struct flow flow = {
+        .dl_type = CONSTANT_HTONS(ETH_TYPE_IP),
+        .nw_proto = IPPROTO_UDP,
+        .nw_ttl = 64,
+        .nw_src = CONSTANT_HTONL(0x0a010101),
+        .nw_dst = CONSTANT_HTONL(0x0a010102),
+        .tp_src = CONSTANT_HTONS(42387),
+        .tp_dst = CONSTANT_HTONS(13264)
+    };
+    size_t ct_start;
+    int error;
+
+    /* Compose CT action with eventmask attribute and check if datapath can
+     * decode the message.  */
+    ofpbuf_init(&actions, 64);
+    ct_start = nl_msg_start_nested(&actions, OVS_ACTION_ATTR_CT);
+    /* Eventmask has no effect without the commit flag, but currently the
+     * datapath will accept an eventmask even without commit.  This is useful
+     * as we do not want to persist the probe connection in the conntrack
+     * table. */
+    nl_msg_put_u32(&actions, OVS_CT_ATTR_EVENTMASK, ~0);
+    nl_msg_end_nested(&actions, ct_start);
+
+    /* Compose a dummy UDP packet. */
+    dp_packet_init(&packet, 0);
+    flow_compose(&packet, &flow);
+
+    /* Execute the actions.  On older datapaths this fails with EINVAL, on
+     * newer datapaths it succeeds. */
+    execute.actions = actions.data;
+    execute.actions_len = actions.size;
+    execute.packet = &packet;
+    execute.flow = &flow;
+    execute.needs_help = false;
+    execute.probe = true;
+    execute.mtu = 0;
+
+    error = dpif_execute(backer->dpif, &execute);
+
+    dp_packet_uninit(&packet);
+    ofpbuf_uninit(&actions);
+
+    if (error) {
+        VLOG_INFO("%s: Datapath does not support eventmask in conntrack action",
+                  dpif_name(backer->dpif));
+    } else {
+        VLOG_INFO("%s: Datapath supports eventmask in conntrack action",
+                  dpif_name(backer->dpif));
+    }
+
+    return !error;
+}
+
 #define CHECK_FEATURE__(NAME, SUPPORT, FIELD, VALUE)                        \
 static bool                                                                 \
 check_##NAME(struct dpif_backer *backer)                                    \
@@ -1300,6 +1361,7 @@  check_support(struct dpif_backer *backer)
     backer->support.tnl_push_pop = dpif_supports_tnl_push_pop(backer->dpif);
     backer->support.clone = check_clone(backer);
     backer->support.sample_nesting = check_max_sample_nesting(backer);
+    backer->support.ct_eventmask = check_ct_eventmask(backer);
 
     /* Flow fields. */
     backer->support.odp.ct_state = check_ct_state(backer);
diff --git a/ofproto/ofproto-dpif.h b/ofproto/ofproto-dpif.h
index 81a0bdf..1fe2e25 100644
--- a/ofproto/ofproto-dpif.h
+++ b/ofproto/ofproto-dpif.h
@@ -174,7 +174,10 @@  struct group_dpif *group_dpif_lookup(struct ofproto_dpif *,
     DPIF_SUPPORT_FIELD(bool, clone, "Clone action")                         \
                                                                             \
     /* Maximum level of nesting allowed by OVS_ACTION_ATTR_SAMPLE action. */\
-    DPIF_SUPPORT_FIELD(size_t, sample_nesting, "Sample nesting")
+    DPIF_SUPPORT_FIELD(size_t, sample_nesting, "Sample nesting")            \
+                                                                            \
+    /* OVS_CT_ATTR_EVENTMASK supported by OVS_ACTION_ATTR_CT action. */     \
+    DPIF_SUPPORT_FIELD(bool, ct_eventmask, "Conntrack eventmask")
 
 /* Stores the various features which the corresponding backer supports. */
 struct dpif_backer_support {