ovn: Fix BFD error config on gateway

The bfd_calculate_chassis function calculates gateway's peer datapaths
to figure out which tunnel's BFD should be enabled to from the current chassis.
Existing algorithm only calculats peer datapaths at one hop, but multiple
logical switches and E/W routers could be in the path, making several hops
which were not considered on the calculation.
It may disable BFD on some gw's tunnel ports. Then a port on a remote ovs
cannot send packet out because it believes all remote gateways are down.

This patch will go through whole graph and visit all datapath's port
which has connection with gateways.

Signed-off-by: Zhenyu Gao <sysugaozhenyu@gmail.com>
Acked-by: Venkata Anil Kommaddi <vkommadi@redhat.com>
Tested-by: Venkata Anil Kommaddi <vkommadi@redhat.com>
Signed-off-by: Russell Bryant <russell@ovn.org>

1 files changed, 84 insertions, 18 deletions

diff --git a/ovn/controller/bfd.c b/ovn/controller/bfd.c
index d1448b13f..efc1482ec 100644
--- a/ovn/controller/bfd.c
+++ b/ovn/controller/bfd.c
@@ -100,6 +100,88 @@ bfd_calculate_active_tunnels(const struct ovsrec_bridge *br_int,
     }
 }
 
+struct local_datapath_node {
+    struct ovs_list node;
+    struct local_datapath *dp;
+};
+
+static void
+bfd_travel_gw_related_chassis(struct local_datapath *dp,
+                              const struct hmap *local_datapaths,
+                              struct ovsdb_idl_index_cursor *cursor,
+                              struct sbrec_port_binding *lpval,
+                              struct sset *bfd_chassis)
+{
+    struct ovs_list dp_list;
+    const struct sbrec_port_binding *pb;
+    struct sset visited_dp = SSET_INITIALIZER(&visited_dp);
+    const char *dp_key;
+    struct local_datapath_node *dp_binding;
+
+    if (!(dp_key = smap_get(&dp->datapath->external_ids, "logical-router")) &&
+        !(dp_key = smap_get(&dp->datapath->external_ids, "logical-switch"))) {
+        VLOG_INFO("datapath has no uuid, cannot travel graph");
+        return;
+    }
+
+    sset_add(&visited_dp, dp_key);
+
+    ovs_list_init(&dp_list);
+    dp_binding = xmalloc(sizeof *dp_binding);
+    dp_binding->dp = dp;
+    ovs_list_push_back(&dp_list, &dp_binding->node);
+
+    /*
+     * Go through whole graph to figure out all chassis which may deliver
+     * packets to gateway. */
+    do {
+        dp_binding = CONTAINER_OF(ovs_list_pop_front(&dp_list),
+                                  struct local_datapath_node, node);
+        dp = dp_binding->dp;
+        free(dp_binding);
+        for (size_t i = 0; i < dp->n_peer_dps; i++) {
+            const struct sbrec_datapath_binding *pdp = dp->peer_dps[i];
+            if (!pdp) {
+                continue;
+            }
+
+            if (!(dp_key = smap_get(&pdp->external_ids, "logical-router")) &&
+                !(dp_key = smap_get(&pdp->external_ids, "logical-switch"))) {
+                continue;
+            }
+
+            if (sset_contains(&visited_dp, dp_key)) {
+                continue;
+            }
+
+            sset_add(&visited_dp, dp_key);
+
+            struct hmap_node *node = hmap_first_with_hash(local_datapaths,
+                                                          pdp->tunnel_key);
+            if (!node) {
+                continue;
+            }
+
+            dp_binding = xmalloc(sizeof *dp_binding);
+            dp_binding->dp = CONTAINER_OF(node, struct local_datapath,
+                                          hmap_node);
+            ovs_list_push_back(&dp_list, &dp_binding->node);
+
+            sbrec_port_binding_index_set_datapath(lpval, pdp);
+            SBREC_PORT_BINDING_FOR_EACH_EQUAL (pb, cursor, lpval) {
+                if (pb->chassis) {
+                    const char *chassis_name = pb->chassis->name;
+                    if (chassis_name) {
+                        sset_add(bfd_chassis, chassis_name);
+                    }
+                }
+            }
+        }
+    } while (!ovs_list_is_empty(&dp_list));
+
+    sset_destroy(&visited_dp);
+}
+
 static void
 bfd_calculate_chassis(struct controller_ctx *ctx,
                       const struct sbrec_chassis *our_chassis,
@@ -155,24 +237,8 @@ bfd_calculate_chassis(struct controller_ctx *ctx,
             }
         }
         if (our_chassis_is_gw_for_dp) {
-            for (size_t i = 0; i < dp->n_peer_dps; i++) {
-                const struct sbrec_datapath_binding *pdp = dp->peer_dps[i];
-                if (!pdp) {
-                    continue;
-                }
-
-                sbrec_port_binding_index_set_datapath(lpval, pdp);
-                SBREC_PORT_BINDING_FOR_EACH_EQUAL (pb, &cursor, lpval) {
-                    if (pb->chassis) {
-                        /* Gateway node has to enable bfd to all nodes hosting
-                         * connected network ports */
-                        const char *chassis_name = pb->chassis->name;
-                        if (chassis_name) {
-                            sset_add(bfd_chassis, chassis_name);
-                        }
-                    }
-                }
-            }
+            bfd_travel_gw_related_chassis(dp, local_datapaths, &cursor,
+                                          lpval, bfd_chassis);
         }
     }
     sbrec_port_binding_index_destroy_row(lpval);