ovn-controller: Detect OVS datapath capabilities.

Automatically create an OVS Datapath record if none exists for the
current br-int datapath type.

Add a 'features' module to track which OVS features are available in
the datapath currently being used.  For now, only ct_all_zero_nat is
tracked, all other features are assumed to be on-par between all
datapaths.

A future commit will make use of the 'features' module to conditionally
program openflows based on available datapath features.

Signed-off-by: Dumitru Ceara <dceara@redhat.com>

controller/ovn-controller.c

@@ -46,6 +46,7 @@
 #include "openvswitch/vconn.h"
 #include "openvswitch/vlog.h"
 #include "ovn/actions.h"
+#include "ovn/features.h"
 #include "lib/chassis-index.h"
 #include "lib/extend-table.h"
 #include "lib/ip-mcast-index.h"
@@ -88,13 +89,16 @@ static unixctl_cb_func lflow_cache_show_stats_cmd;
 static unixctl_cb_func debug_delay_nb_cfg_report;
 
 #define DEFAULT_BRIDGE_NAME "br-int"
+#define DEFAULT_DATAPATH "system"
 #define DEFAULT_PROBE_INTERVAL_MSEC 5000
 #define OFCTRL_DEFAULT_PROBE_INTERVAL_SEC 0
 
 #define CONTROLLER_LOOP_STOPWATCH_NAME "ovn-controller-flow-generation"
 
 #define OVS_NB_CFG_NAME "ovn-nb-cfg"
 
+#define OVS_CT_ALL_ZERO_NAT_FEATURE "ct_all_zero_nat"
+
 static char *parse_options(int argc, char *argv[]);
 OVS_NO_RETURN static void usage(void);
 
@@ -314,10 +318,6 @@ static const struct ovsrec_bridge *
 create_br_int(struct ovsdb_idl_txn *ovs_idl_txn,
               const struct ovsrec_open_vswitch_table *ovs_table)
 {
-    if (!ovs_idl_txn) {
-        return NULL;
-    }
-
     const struct ovsrec_open_vswitch *cfg;
     cfg = ovsrec_open_vswitch_table_first(ovs_table);
     if (!cfg) {
@@ -381,6 +381,21 @@ create_br_int(struct ovsdb_idl_txn *ovs_idl_txn,
     return bridge;
 }
 
+static const struct ovsrec_datapath *
+create_br_datapath(struct ovsdb_idl_txn *ovs_idl_txn,
+                   const struct ovsrec_open_vswitch *cfg,
+                   const char *datapath_type)
+{
+    ovsdb_idl_txn_add_comment(ovs_idl_txn,
+                              "ovn-controller: creating bridge datapath '%s'",
+                              datapath_type);
+
+    struct ovsrec_datapath *dp = ovsrec_datapath_insert(ovs_idl_txn);
+    ovsrec_open_vswitch_verify_datapaths(cfg);
+    ovsrec_open_vswitch_update_datapaths_setkey(cfg, datapath_type, dp);
+    return dp;
+}
+
 static const struct ovsrec_bridge *
 get_br_int(const struct ovsrec_bridge_table *bridge_table,
            const struct ovsrec_open_vswitch_table *ovs_table)
@@ -394,33 +409,79 @@ get_br_int(const struct ovsrec_bridge_table *bridge_table,
     return get_bridge(bridge_table, br_int_name(cfg));
 }
 
-static const struct ovsrec_bridge *
+static const struct ovsrec_datapath *
+get_br_datapath(const struct ovsrec_open_vswitch *cfg,
+                const char *datapath_type)
+{
+    for (size_t i = 0; i < cfg->n_datapaths; i++) {
+        if (!strcmp(cfg->key_datapaths[i], datapath_type)) {
+            return cfg->value_datapaths[i];
+        }
+    }
+    return NULL;
+}
+
+static void
 process_br_int(struct ovsdb_idl_txn *ovs_idl_txn,
                const struct ovsrec_bridge_table *bridge_table,
-               const struct ovsrec_open_vswitch_table *ovs_table)
+               const struct ovsrec_open_vswitch_table *ovs_table,
+               const struct ovsrec_bridge **br_int_,
+               const struct ovsrec_datapath **br_int_dp_)
 {
-    const struct ovsrec_bridge *br_int = get_br_int(bridge_table,
-                                                    ovs_table);
-    if (!br_int) {
-        br_int = create_br_int(ovs_idl_txn, ovs_table);
-    }
-    if (br_int && ovs_idl_txn) {
-        const struct ovsrec_open_vswitch *cfg;
-        cfg = ovsrec_open_vswitch_table_first(ovs_table);
-        ovs_assert(cfg);
-        const char *datapath_type = smap_get(&cfg->external_ids,
-                                             "ovn-bridge-datapath-type");
-        /* Check for the datapath_type and set it only if it is defined in
-         * cfg. */
-        if (datapath_type && strcmp(br_int->datapath_type, datapath_type)) {
-            ovsrec_bridge_set_datapath_type(br_int, datapath_type);
+    const struct ovsrec_bridge *br_int = get_br_int(bridge_table, ovs_table);
+    const struct ovsrec_datapath *br_int_dp = NULL;
+    if (ovs_idl_txn) {
+        if (!br_int) {
+            br_int = create_br_int(ovs_idl_txn, ovs_table);
         }
-        if (!br_int->fail_mode || strcmp(br_int->fail_mode, "secure")) {
-            ovsrec_bridge_set_fail_mode(br_int, "secure");
-            VLOG_WARN("Integration bridge fail-mode changed to 'secure'.");
+
+        if (br_int) {
+            const struct ovsrec_open_vswitch *cfg =
+                ovsrec_open_vswitch_table_first(ovs_table);
+            ovs_assert(cfg);
+
+            /* Propagate "ovn-bridge-datapath-type" from OVS table, if any.
+             * Otherwise use the datapath-type set in br-int, if any.
+             * Finally, assume "system" datapath if none configured.
+             */
+            const char *datapath_type =
+                smap_get(&cfg->external_ids, "ovn-bridge-datapath-type");
+
+            if (!datapath_type) {
+                if (br_int->datapath_type[0]) {
+                    datapath_type = br_int->datapath_type;
+                } else {
+                    datapath_type = DEFAULT_DATAPATH;
+                }
+            }
+            if (strcmp(br_int->datapath_type, datapath_type)) {
+                ovsrec_bridge_set_datapath_type(br_int, datapath_type);
+            }
+            if (!br_int->fail_mode || strcmp(br_int->fail_mode, "secure")) {
+                ovsrec_bridge_set_fail_mode(br_int, "secure");
+                VLOG_WARN("Integration bridge fail-mode changed to 'secure'.");
+            }
+            br_int_dp = get_br_datapath(cfg, datapath_type);
+            if (!br_int_dp) {
+                br_int_dp = create_br_datapath(ovs_idl_txn, cfg,
+                                               datapath_type);
+            }
         }
     }
-    return br_int;
+    *br_int_ = br_int;
+    *br_int_dp_ = br_int_dp;
+}
+
+/* Returns 'true' if the feature set supported by 'ovs_datapath' have been
+ * updated since the last call.
+ */
+static bool
+process_ovs_datapath(const struct ovsrec_datapath *ovs_datapath)
+{
+    bool ct_all_zero_nat = smap_get_bool(&ovs_datapath->capabilities,
+                                         OVS_CT_ALL_ZERO_NAT_FEATURE,
+                                         false);
+    return ovs_feature_support_update(ct_all_zero_nat);
 }
 
 static const char *
@@ -835,6 +896,7 @@ ctrl_register_ovs_idl(struct ovsdb_idl *ovs_idl)
     ovsdb_idl_add_table(ovs_idl, &ovsrec_table_open_vswitch);
     ovsdb_idl_add_column(ovs_idl, &ovsrec_open_vswitch_col_external_ids);
     ovsdb_idl_add_column(ovs_idl, &ovsrec_open_vswitch_col_bridges);
+    ovsdb_idl_add_column(ovs_idl, &ovsrec_open_vswitch_col_datapaths);
     ovsdb_idl_add_table(ovs_idl, &ovsrec_table_interface);
     ovsdb_idl_track_add_column(ovs_idl, &ovsrec_interface_col_name);
     ovsdb_idl_track_add_column(ovs_idl, &ovsrec_interface_col_bfd);
@@ -857,6 +919,8 @@ ctrl_register_ovs_idl(struct ovsdb_idl *ovs_idl)
     ovsdb_idl_add_column(ovs_idl, &ovsrec_ssl_col_ca_cert);
     ovsdb_idl_add_column(ovs_idl, &ovsrec_ssl_col_certificate);
     ovsdb_idl_add_column(ovs_idl, &ovsrec_ssl_col_private_key);
+    ovsdb_idl_add_table(ovs_idl, &ovsrec_table_datapath);
+    ovsdb_idl_add_column(ovs_idl, &ovsrec_datapath_col_capabilities);
     chassis_register_ovs_idl(ovs_idl);
     encaps_register_ovs_idl(ovs_idl);
     binding_register_ovs_idl(ovs_idl);
@@ -2964,8 +3028,10 @@ main(int argc, char *argv[])
             ovsrec_bridge_table_get(ovs_idl_loop.idl);
         const struct ovsrec_open_vswitch_table *ovs_table =
             ovsrec_open_vswitch_table_get(ovs_idl_loop.idl);
-        const struct ovsrec_bridge *br_int =
-            process_br_int(ovs_idl_txn, bridge_table, ovs_table);
+        const struct ovsrec_bridge *br_int = NULL;
+        const struct ovsrec_datapath *br_int_dp = NULL;
+        process_br_int(ovs_idl_txn, bridge_table, ovs_table,
+                       &br_int, &br_int_dp);
 
         if (ovsdb_idl_has_ever_connected(ovnsb_idl_loop.idl) &&
             northd_version_match) {
@@ -2996,6 +3062,12 @@ main(int argc, char *argv[])
                                       &chassis_private);
             }
 
+            /* If any OVS feature support changed, force a full recompute. */
+            if (br_int_dp && process_ovs_datapath(br_int_dp)) {
+                VLOG_INFO("OVS feature set changed, force recompute.");
+                engine_set_force_recompute(true);
+            }
+
             if (br_int) {
                 ct_zones_data = engine_get_data(&en_ct_zones);
                 if (ct_zones_data) {

include/ovn/features.h

@@ -16,7 +16,19 @@
 #ifndef OVN_FEATURES_H
 #define OVN_FEATURES_H 1
 
+#include <stdbool.h>
+
 /* ovn-controller supported feature names. */
 #define OVN_FEATURE_PORT_UP_NOTIF "port-up-notif"
 
+/* OVS datapath supported features.  Based on availability OVN might generate
+ * different types of openflows.
+ */
+struct ovs_feature_support {
+    bool ct_all_zero_nat;
+};
+
+const struct ovs_feature_support *ovs_feature_support_get(void);
+bool ovs_feature_support_update(bool ct_all_zero_snat);
+
 #endif

lib/automake.mk

@@ -13,6 +13,7 @@ lib_libovn_la_SOURCES = \
 	lib/expr.c \
 	lib/extend-table.h \
 	lib/extend-table.c \
+	lib/features.c \
 	lib/ovn-parallel-hmap.h \
 	lib/ovn-parallel-hmap.c \
 	lib/ip-mcast-index.c \

lib/features.c

@@ -0,0 +1,39 @@
+/* Copyright (c) 2021, Red Hat, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <config.h>
+
+#include "ovn/features.h"
+
+static struct ovs_feature_support ovs_features;
+
+const struct ovs_feature_support *
+ovs_feature_support_get(void)
+{
+    return &ovs_features;
+}
+
+/* Returns 'true' if the OVS feature set has been updated since the last
+ * call.
+ */
+bool
+ovs_feature_support_update(bool ct_all_zero_nat)
+{
+    if (ovs_features.ct_all_zero_nat != ct_all_zero_nat) {
+        ovs_features.ct_all_zero_nat = ct_all_zero_nat;
+        return true;
+    }
+    return false;
+}

tests/ovn-controller.at

@@ -151,23 +151,25 @@ sysid=$(ovs-vsctl get Open_vSwitch . external_ids:system-id)
 check_datapath_type () {
     datapath_type=$1
     chassis_datapath_type=$(ovn-sbctl get Chassis ${sysid} other_config:datapath-type | sed -e 's/"//g') #"
+    ovs_datapath_type=$(ovs-vsctl get Bridge br-int datapath-type)
     test "${datapath_type}" = "${chassis_datapath_type}"
+    test "${datapath_type}" = "${ovs_datapath_type}"
 }
 
-OVS_WAIT_UNTIL([check_datapath_type ""])
+OVS_WAIT_UNTIL([check_datapath_type system])
 
 ovs-vsctl set Bridge br-int datapath-type=foo
 OVS_WAIT_UNTIL([check_datapath_type foo])
 
 # Change "ovn-bridge-mappings" value. It should not change the "datapath-type".
 ovs-vsctl set Open_vSwitch . external_ids:ovn-bridge-mappings=foo-mapping
-check_datapath_type foo
+check_datapath_type system
 
 ovs-vsctl set Bridge br-int datapath-type=bar
 OVS_WAIT_UNTIL([check_datapath_type bar])
 
 ovs-vsctl set Bridge br-int datapath-type=\"\"
-OVS_WAIT_UNTIL([check_datapath_type ""])
+OVS_WAIT_UNTIL([check_datapath_type system])
 
 # Set the datapath_type in external_ids:ovn-bridge-datapath-type.
 ovs-vsctl set Open_vSwitch . external_ids:ovn-bridge-datapath-type=foo
@@ -176,11 +178,9 @@ OVS_WAIT_UNTIL([check_datapath_type foo])
 # Change the br-int's datapath type to bar.
 # It should be reset to foo since ovn-bridge-datapath-type is configured.
 ovs-vsctl set Bridge br-int datapath-type=bar
-OVS_WAIT_UNTIL([test foo = `ovs-vsctl get Bridge br-int datapath-type`])
 OVS_WAIT_UNTIL([check_datapath_type foo])
 
 ovs-vsctl set Open_vSwitch . external_ids:ovn-bridge-datapath-type=foobar
-OVS_WAIT_UNTIL([test foobar = `ovs-vsctl get Bridge br-int datapath-type`])
 OVS_WAIT_UNTIL([check_datapath_type foobar])
 
 expected_iface_types=$(ovs-vsctl get Open_vSwitch . iface_types | tr -d '[[]] ""')