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From e75d53c69261a0b104c75d8f6f7dc7175a690833 Mon Sep 17 00:00:00 2001
Message-Id: <e75d53c69261a0b104c75d8f6f7dc7175a690833.1610458802.git.lorenzo.bianconi@redhat.com>
In-Reply-To: <f21c1b7a467a691847b5552d4570af706fcc5bb0.1610458802.git.lorenzo.bianconi@redhat.com>
References: <f21c1b7a467a691847b5552d4570af706fcc5bb0.1610458802.git.lorenzo.bianconi@redhat.com>
From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Date: Fri, 8 Jan 2021 17:36:22 +0100
Subject: [PATCH 14/16] controller: bfd: introduce BFD state machine.

Introduce BFD state machine for BFD packet parsing
according to RFC880 https://tools.ietf.org/html/rfc5880.
Introduce BFD logical flows in ovn-northd.

Change-Id: I1ea057ad45393360fa917eb6e3a576dd37cfbc0d
Acked-by: Mark Michelson <mmichels@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Numan Siddique <numans@ovn.org>
---
 NEWS                    |   6 +
 controller/pinctrl.c    | 342 ++++++++++++++++++++++++++++++++++++++--
 northd/ovn-northd.8.xml |  21 +++
 northd/ovn-northd.c     |  85 +++++++++-
 tests/ovn-northd.at     |  55 +++++++
 5 files changed, 488 insertions(+), 21 deletions(-)

diff --git a/NEWS b/NEWS
index f71ec329c..85f63503e 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,9 @@
+Post-v20.12.0
+-------------------------
+  - Support ECMP multiple nexthops for reroute router policies.
+   - BFD protocol support according to RFC880 [0]. IPv6 is not suported yet.
+     [0] https://tools.ietf.org/html/rfc5880)
+
 OVN v20.12.0 - 18 Dec 2020
 --------------------------
    - The "datapath" argument to ovn-trace is now optional, since the
diff --git a/controller/pinctrl.c b/controller/pinctrl.c
index deeae7479..6e363a0f9 100644
--- a/controller/pinctrl.c
+++ b/controller/pinctrl.c
@@ -330,9 +330,10 @@ static void bfd_monitor_destroy(void);
 static void bfd_monitor_send_msg(struct rconn *swconn, long long int *bfd_time)
                                  OVS_REQUIRES(pinctrl_mutex);
 static void
-pinctrl_handle_bfd_msg(void)
+pinctrl_handle_bfd_msg(const struct flow *ip_flow, struct dp_packet *pkt_in)
                        OVS_REQUIRES(pinctrl_mutex);
-static void bfd_monitor_run(const struct sbrec_bfd_table *bfd_table,
+static void bfd_monitor_run(struct ovsdb_idl_txn *ovnsb_idl_txn,
+                            const struct sbrec_bfd_table *bfd_table,
                             struct ovsdb_idl_index *sbrec_port_binding_by_name,
                             const struct sbrec_chassis *chassis,
                             const struct sset *active_tunnels)
@@ -2980,7 +2981,7 @@ process_packet_in(struct rconn *swconn, const struct ofp_header *msg)
 
     case ACTION_OPCODE_BFD_MSG:
         ovs_mutex_lock(&pinctrl_mutex);
-        pinctrl_handle_bfd_msg();
+        pinctrl_handle_bfd_msg(&headers, &packet);
         ovs_mutex_unlock(&pinctrl_mutex);
         break;
 
@@ -3206,10 +3207,8 @@ pinctrl_run(struct ovsdb_idl_txn *ovnsb_idl_txn,
                          local_datapaths);
     sync_svc_monitors(ovnsb_idl_txn, svc_mon_table, sbrec_port_binding_by_name,
                       chassis);
-    if (ovnsb_idl_txn) {
-        bfd_monitor_run(bfd_table, sbrec_port_binding_by_name, chassis,
-                        active_tunnels);
-    }
+    bfd_monitor_run(ovnsb_idl_txn, bfd_table, sbrec_port_binding_by_name,
+                    chassis, active_tunnels);
     ovs_mutex_unlock(&pinctrl_mutex);
 }
 
@@ -6345,8 +6344,48 @@ sync_svc_monitors(struct ovsdb_idl_txn *ovnsb_idl_txn,
 
 }
 
+enum bfd_state {
+    BFD_STATE_ADMIN_DOWN,
+    BFD_STATE_DOWN,
+    BFD_STATE_INIT,
+    BFD_STATE_UP,
+};
+
+enum bfd_flags {
+    BFD_FLAG_MULTIPOINT = 1 << 0,
+    BFD_FLAG_DEMAND = 1 << 1,
+    BFD_FLAG_AUTH = 1 << 2,
+    BFD_FLAG_CTL = 1 << 3,
+    BFD_FLAG_FINAL = 1 << 4,
+    BFD_FLAG_POLL = 1 << 5
+};
+
+#define BFD_FLAGS_MASK  0x3f
+
+static char *
+bfd_get_status(enum bfd_state state)
+{
+    switch (state) {
+    case BFD_STATE_ADMIN_DOWN:
+        return "admin_down";
+    case BFD_STATE_DOWN:
+        return "down";
+    case BFD_STATE_INIT:
+        return "init";
+    case BFD_STATE_UP:
+        return "up";
+    default:
+        return "";
+    }
+}
+
 static struct hmap bfd_monitor_map;
 
+#define BFD_UPDATE_BATCH_TH     10
+static uint16_t bfd_pending_update;
+#define BFD_UPDATE_TIMEOUT      5000LL
+static long long bfd_last_update;
+
 struct bfd_entry {
     struct hmap_node node;
     bool erase;
@@ -6365,11 +6404,23 @@ struct bfd_entry {
      * sessions on the system
      */
     uint16_t udp_src;
-    ovs_be32 disc;
+    ovs_be32 local_disc;
+    ovs_be32 remote_disc;
+
+    uint32_t local_min_tx;
+    uint32_t local_min_rx;
+    uint32_t remote_min_rx;
+
+    uint8_t local_mult;
 
     int64_t port_key;
     int64_t metadata;
 
+    enum bfd_state state;
+    bool change_state;
+
+    uint32_t detection_timeout;
+    long long int last_rx;
     long long int next_tx;
 };
 
@@ -6377,6 +6428,7 @@ static void
 bfd_monitor_init(void)
 {
     hmap_init(&bfd_monitor_map);
+    bfd_last_update = time_msec();
 }
 
 static void
@@ -6402,6 +6454,24 @@ pinctrl_find_bfd_monitor_entry_by_port(char *ip, uint16_t port)
     return NULL;
 }
 
+static struct bfd_entry *
+pinctrl_find_bfd_monitor_entry_by_disc(ovs_be32 ip, ovs_be32 disc)
+{
+    char *ip_src = xasprintf(IP_FMT, IP_ARGS(ip));
+    struct bfd_entry *ret = NULL, *entry;
+
+    HMAP_FOR_EACH_WITH_HASH (entry, node, hash_string(ip_src, 0),
+                             &bfd_monitor_map) {
+        if (entry->local_disc == disc) {
+            ret = entry;
+            break;
+        }
+    }
+
+    free(ip_src);
+    return ret;
+}
+
 static bool
 bfd_monitor_should_inject(void)
 {
@@ -6453,9 +6523,60 @@ bfd_monitor_put_bfd_msg(struct bfd_entry *entry, struct dp_packet *packet)
     udp->udp_dst = htons(BFD_DEST_PORT);
     udp->udp_len = htons(sizeof *udp + sizeof *msg);
 
-    msg = dp_packet_put_uninit(packet, sizeof *msg);
+    msg = dp_packet_put_zeros(packet, sizeof *msg);
     msg->vers_diag = (BFD_VERSION << 5);
+    msg->mult = entry->local_mult;
     msg->length = BFD_PACKET_LEN;
+    msg->flags = entry->state << 6;
+    msg->my_disc = entry->local_disc;
+    msg->your_disc = entry->remote_disc;
+    /* min_tx and min_rx are in us - RFC 5880 page 9 */
+    msg->min_tx = htonl(entry->local_min_tx * 1000);
+    msg->min_rx = htonl(entry->local_min_rx * 1000);
+}
+
+static bool
+bfd_monitor_need_update(void)
+{
+    long long int cur_time = time_msec();
+
+    if (bfd_pending_update == BFD_UPDATE_BATCH_TH) {
+        goto update;
+    }
+
+    if (bfd_pending_update &&
+        bfd_last_update + BFD_UPDATE_TIMEOUT < cur_time) {
+        goto update;
+    }
+    return false;
+
+update:
+    bfd_last_update = cur_time;
+    bfd_pending_update = 0;
+    return true;
+}
+
+static void
+bfd_check_detection_timeout(struct bfd_entry *entry)
+{
+    if (entry->state == BFD_STATE_ADMIN_DOWN) {
+        return;
+    }
+
+    if (!entry->detection_timeout) {
+        return;
+    }
+
+    long long int cur_time = time_msec();
+    if (cur_time < entry->last_rx + entry->detection_timeout) {
+        return;
+    }
+
+    entry->state = BFD_STATE_DOWN;
+    entry->change_state = true;
+    bfd_last_update = cur_time;
+    bfd_pending_update = 0;
+    notify_pinctrl_main();
 }
 
 static void
@@ -6465,11 +6586,27 @@ bfd_monitor_send_msg(struct rconn *swconn, long long int *bfd_time)
     long long int cur_time = time_msec();
     struct bfd_entry *entry;
 
+    if (bfd_monitor_need_update()) {
+        notify_pinctrl_main();
+    }
+
     HMAP_FOR_EACH (entry, node, &bfd_monitor_map) {
+        unsigned long tx_timeout;
+
+        bfd_check_detection_timeout(entry);
+
         if (cur_time < entry->next_tx) {
             goto next;
         }
 
+        if (!entry->remote_min_rx) {
+            continue;
+        }
+
+        if (entry->state == BFD_STATE_ADMIN_DOWN) {
+            continue;
+        }
+
         uint64_t packet_stub[256 / 8];
         struct dp_packet packet;
         dp_packet_use_stub(&packet, packet_stub, sizeof packet_stub);
@@ -6504,7 +6641,9 @@ bfd_monitor_send_msg(struct rconn *swconn, long long int *bfd_time)
         dp_packet_uninit(&packet);
         ofpbuf_uninit(&ofpacts);
 
-        entry->next_tx = cur_time + 5000;
+        tx_timeout = MAX(entry->local_min_tx, entry->remote_min_rx);
+        tx_timeout -= random_range((tx_timeout * 25) / 100);
+        entry->next_tx = cur_time + tx_timeout;
 next:
         if (*bfd_time > entry->next_tx) {
             *bfd_time = entry->next_tx;
@@ -6512,14 +6651,167 @@ next:
     }
 }
 
+static bool
+pinctrl_check_bfd_msg(const struct flow *ip_flow, struct dp_packet *pkt_in)
+{
+    if (ip_flow->dl_type != htons(ETH_TYPE_IP) &&
+        ip_flow->dl_type != htons(ETH_TYPE_IPV6)) {
+        return false;
+    }
+
+    if (ip_flow->nw_proto != IPPROTO_UDP) {
+        return false;
+    }
+
+    struct udp_header *udp_hdr = dp_packet_l4(pkt_in);
+    if (udp_hdr->udp_dst != htons(BFD_DEST_PORT)) {
+        return false;
+    }
+
+    const struct bfd_msg *msg = dp_packet_get_udp_payload(pkt_in);
+    uint8_t version = msg->vers_diag >> 5;
+    if (version != BFD_VERSION) {
+        return false;
+    }
+
+    enum bfd_flags flags = msg->flags & BFD_FLAGS_MASK;
+    if (flags & BFD_FLAG_AUTH) {
+        /* AUTH not supported yet */
+        return false;
+    }
+
+    if (msg->length < BFD_PACKET_LEN) {
+        return false;
+    }
+
+    if (!msg->mult) {
+        return false;
+    }
+
+    if (flags & BFD_FLAG_MULTIPOINT) {
+        return false;
+    }
+
+    if (!msg->my_disc) {
+        return false;
+    }
+
+    enum bfd_state peer_state = msg->flags >> 6;
+    if (peer_state >= BFD_STATE_INIT && !msg->your_disc) {
+        return false;
+    }
+
+    return true;
+}
+
 static void
-pinctrl_handle_bfd_msg(void)
+pinctrl_handle_bfd_msg(const struct flow *ip_flow, struct dp_packet *pkt_in)
     OVS_REQUIRES(pinctrl_mutex)
 {
+    if (!pinctrl_check_bfd_msg(ip_flow, pkt_in)) {
+        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
+        VLOG_WARN_RL(&rl, "BFD packet discarded");
+        return;
+    }
+
+    const struct bfd_msg *msg = dp_packet_get_udp_payload(pkt_in);
+    struct bfd_entry *entry = pinctrl_find_bfd_monitor_entry_by_disc(
+            ip_flow->nw_src, msg->your_disc);
+    if (!entry) {
+        return;
+    }
+
+    bool change_state = false;
+    entry->remote_disc = msg->my_disc;
+    uint32_t remote_min_tx = ntohl(msg->min_tx) / 1000;
+    entry->remote_min_rx = ntohl(msg->min_rx) / 1000;
+    entry->detection_timeout = msg->mult * MAX(remote_min_tx,
+                                               entry->local_min_rx);
+
+    enum bfd_state peer_state = msg->flags >> 6;
+    if (peer_state == BFD_STATE_ADMIN_DOWN &&
+        entry->state >= BFD_STATE_INIT) {
+        entry->state = BFD_STATE_DOWN;
+        entry->last_rx = time_msec();
+        change_state = true;
+        goto out;
+    }
+
+    /* bfd state machine */
+    switch (entry->state) {
+    case BFD_STATE_DOWN:
+        if (peer_state == BFD_STATE_DOWN) {
+            entry->state = BFD_STATE_INIT;
+            change_state = true;
+        }
+        if (peer_state == BFD_STATE_INIT) {
+            entry->state = BFD_STATE_UP;
+            change_state = true;
+        }
+        entry->last_rx = time_msec();
+        break;
+    case BFD_STATE_INIT:
+        if (peer_state == BFD_STATE_INIT ||
+            peer_state == BFD_STATE_UP) {
+            entry->state = BFD_STATE_UP;
+            change_state = true;
+        }
+        if (peer_state == BFD_STATE_ADMIN_DOWN) {
+            entry->state = BFD_STATE_DOWN;
+            change_state = true;
+        }
+        entry->last_rx = time_msec();
+        break;
+    case BFD_STATE_UP:
+        if (peer_state == BFD_STATE_ADMIN_DOWN ||
+            peer_state == BFD_STATE_DOWN) {
+            entry->state = BFD_STATE_DOWN;
+            change_state = true;
+        }
+        entry->last_rx = time_msec();
+        break;
+    case BFD_STATE_ADMIN_DOWN:
+    default:
+        break;
+    }
+
+out:
+    /* let's try to bacth db updates */
+    if (change_state) {
+        entry->change_state = true;
+        bfd_pending_update++;
+    }
+    if (bfd_monitor_need_update()) {
+        notify_pinctrl_main();
+    }
+}
+
+static void
+bfd_monitor_check_sb_conf(const struct sbrec_bfd *sb_bt,
+                          struct bfd_entry *entry)
+{
+    ovs_be32 ip_dst;
+
+    if (ip_parse(sb_bt->dst_ip, &ip_dst) && ip_dst != entry->ip_dst) {
+        entry->ip_dst = ip_dst;
+    }
+
+    if (sb_bt->min_tx != entry->local_min_tx) {
+        entry->local_min_tx = sb_bt->min_tx;
+    }
+
+    if (sb_bt->min_rx != entry->local_min_rx) {
+        entry->local_min_rx = sb_bt->min_rx;
+    }
+
+    if (sb_bt->detect_mult != entry->local_mult) {
+        entry->local_mult = sb_bt->detect_mult;
+    }
 }
 
 static void
-bfd_monitor_run(const struct sbrec_bfd_table *bfd_table,
+bfd_monitor_run(struct ovsdb_idl_txn *ovnsb_idl_txn,
+                const struct sbrec_bfd_table *bfd_table,
                 struct ovsdb_idl_index *sbrec_port_binding_by_name,
                 const struct sbrec_chassis *chassis,
                 const struct sset *active_tunnels)
@@ -6599,15 +6891,39 @@ bfd_monitor_run(const struct sbrec_bfd_table *bfd_table,
             entry->ip_src = ip_src;
             entry->ip_dst = ip_dst;
             entry->udp_src = bt->src_port;
-            entry->disc = htonl(bt->disc);
+            entry->local_disc = htonl(bt->disc);
             entry->next_tx = cur_time;
+            entry->last_rx = cur_time;
+            entry->detection_timeout = 30000;
             entry->metadata = pb->datapath->tunnel_key;
             entry->port_key = pb->tunnel_key;
+            entry->state = BFD_STATE_ADMIN_DOWN;
+            entry->local_min_tx = bt->min_tx;
+            entry->local_min_rx = bt->min_rx;
+            entry->remote_min_rx = 1; /* RFC5880 page 29 */
+            entry->local_mult = bt->detect_mult;
 
             uint32_t hash = hash_string(bt->dst_ip, 0);
             hmap_insert(&bfd_monitor_map, &entry->node, hash);
+        } else if (!strcmp(bt->status, "admin_down") &&
+                   entry->state != BFD_STATE_ADMIN_DOWN) {
+            entry->state = BFD_STATE_ADMIN_DOWN;
+            entry->change_state = false;
+            entry->remote_disc = 0;
+        } else if (strcmp(bt->status, "admin_down") &&
+                   entry->state == BFD_STATE_ADMIN_DOWN) {
+            entry->state = BFD_STATE_DOWN;
+            entry->change_state = false;
+            entry->remote_disc = 0;
             changed = true;
+        } else if (entry->change_state && ovnsb_idl_txn) {
+            if (entry->state == BFD_STATE_DOWN) {
+                entry->remote_disc = 0;
+            }
+            sbrec_bfd_set_status(bt, bfd_get_status(entry->state));
+            entry->change_state = false;
         }
+        bfd_monitor_check_sb_conf(bt, entry);
         entry->erase = false;
     }
 
diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
index 1f0f71f34..48c52a56a 100644
--- a/northd/ovn-northd.8.xml
+++ b/northd/ovn-northd.8.xml
@@ -1936,6 +1936,27 @@ next;
         </p>
       </li>
 
+      <li>
+        <p>
+            For each BFD port the two following priority-110 flows are added
+            to manage BFD traffic:
+
+            <ul>
+              <li>
+               if <code>ip4.src</code> or <code>ip6.src</code> is any IP
+               address owned by the router port and <code>udp.dst == 3784
+               </code>, the packet is advanced to the next pipeline stage.
+              </li>
+
+              <li>
+               if <code>ip4.dst</code> or <code>ip6.dst</code> is any IP
+               address owned by the router port and <code>udp.dst == 3784
+               </code>, the <code>handle_bfd_msg</code> action is executed.
+              </li>
+            </ul>
+        </p>
+      </li>
+
       <li>
         <p>
           L3 admission control: A priority-100 flow drops packets that match
diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
index 77ea2181c..363bb0895 100644
--- a/northd/ovn-northd.c
+++ b/northd/ovn-northd.c
@@ -1473,6 +1473,8 @@ struct ovn_port {
 
     bool has_unknown; /* If the addresses have 'unknown' defined. */
 
+    bool has_bfd;
+
     /* The port's peer:
      *
      *     - A switch port S of type "router" has a router port R as a peer,
@@ -7597,7 +7599,8 @@ static int bfd_get_unused_port(unsigned long *bfd_src_ports)
 }
 
 static void
-build_bfd_table(struct northd_context *ctx, struct hmap *bfd_connections)
+build_bfd_table(struct northd_context *ctx, struct hmap *bfd_connections,
+                struct hmap *ports)
 {
     struct hmap sb_only = HMAP_INITIALIZER(&sb_only);
     const struct sbrec_bfd *sb_bt;
@@ -7661,9 +7664,18 @@ build_bfd_table(struct northd_context *ctx, struct hmap *bfd_connections)
             hash = hash_string(bfd_e->sb_bt->logical_port, hash);
             hmap_insert(bfd_connections, &bfd_e->hmap_node, hash);
         }
+
+        struct ovn_port *op = ovn_port_find(ports, nb_bt->logical_port);
+        if (op) {
+            op->has_bfd = true;
+        }
     }
 
     HMAP_FOR_EACH_POP (bfd_e, hmap_node, &sb_only) {
+        struct ovn_port *op = ovn_port_find(ports, bfd_e->sb_bt->logical_port);
+        if (op) {
+            op->has_bfd = false;
+        }
         sbrec_bfd_delete(bfd_e->sb_bt);
         free(bfd_e);
     }
@@ -8423,16 +8435,15 @@ add_route(struct hmap *lflows, const struct ovn_port *op,
     build_route_match(op_inport, network_s, plen, is_src_route, is_ipv4,
                       &match, &priority);
 
-    struct ds actions = DS_EMPTY_INITIALIZER;
-    ds_put_format(&actions, "ip.ttl--; "REG_ECMP_GROUP_ID" = 0; %s = ",
+    struct ds common_actions = DS_EMPTY_INITIALIZER;
+    ds_put_format(&common_actions, REG_ECMP_GROUP_ID" = 0; %s = ",
                   is_ipv4 ? REG_NEXT_HOP_IPV4 : REG_NEXT_HOP_IPV6);
-
     if (gateway) {
-        ds_put_cstr(&actions, gateway);
+        ds_put_cstr(&common_actions, gateway);
     } else {
-        ds_put_format(&actions, "ip%s.dst", is_ipv4 ? "4" : "6");
+        ds_put_format(&common_actions, "ip%s.dst", is_ipv4 ? "4" : "6");
     }
-    ds_put_format(&actions, "; "
+    ds_put_format(&common_actions, "; "
                   "%s = %s; "
                   "eth.src = %s; "
                   "outport = %s; "
@@ -8442,11 +8453,20 @@ add_route(struct hmap *lflows, const struct ovn_port *op,
                   lrp_addr_s,
                   op->lrp_networks.ea_s,
                   op->json_key);
+    struct ds actions = DS_EMPTY_INITIALIZER;
+    ds_put_format(&actions, "ip.ttl--; %s", ds_cstr(&common_actions));
 
     ovn_lflow_add_with_hint(lflows, op->od, S_ROUTER_IN_IP_ROUTING, priority,
                             ds_cstr(&match), ds_cstr(&actions),
                             stage_hint);
+    if (op->has_bfd) {
+        ds_put_format(&match, " && udp.dst == 3784");
+        ovn_lflow_add_with_hint(lflows, op->od, S_ROUTER_IN_IP_ROUTING,
+                                priority + 1, ds_cstr(&match),
+                                ds_cstr(&common_actions), stage_hint);
+    }
     ds_destroy(&match);
+    ds_destroy(&common_actions);
     ds_destroy(&actions);
 }
 
@@ -9108,6 +9128,52 @@ build_lrouter_force_snat_flows(struct hmap *lflows, struct ovn_datapath *od,
     ds_destroy(&actions);
 }
 
+static void
+build_lrouter_bfd_flows(struct hmap *lflows, struct ovn_port *op)
+{
+    if (!op->has_bfd) {
+        return;
+    }
+
+    struct ds ip_list = DS_EMPTY_INITIALIZER;
+    struct ds match = DS_EMPTY_INITIALIZER;
+
+    if (op->lrp_networks.n_ipv4_addrs) {
+        op_put_v4_networks(&ip_list, op, false);
+        ds_put_format(&match, "ip4.src == %s && udp.dst == 3784",
+                      ds_cstr(&ip_list));
+        ovn_lflow_add_with_hint(lflows, op->od, S_ROUTER_IN_IP_INPUT, 110,
+                                ds_cstr(&match), "next; ",
+                                &op->nbrp->header_);
+        ds_clear(&match);
+        ds_put_format(&match, "ip4.dst == %s && udp.dst == 3784",
+                      ds_cstr(&ip_list));
+        ovn_lflow_add_with_hint(lflows, op->od, S_ROUTER_IN_IP_INPUT, 110,
+                                ds_cstr(&match), "handle_bfd_msg(); ",
+                                &op->nbrp->header_);
+    }
+    if (op->lrp_networks.n_ipv6_addrs) {
+        ds_clear(&ip_list);
+        ds_clear(&match);
+
+        op_put_v6_networks(&ip_list, op);
+        ds_put_format(&match, "ip6.src == %s && udp.dst == 3784",
+                      ds_cstr(&ip_list));
+        ovn_lflow_add_with_hint(lflows, op->od, S_ROUTER_IN_IP_INPUT, 110,
+                                ds_cstr(&match), "next; ",
+                                &op->nbrp->header_);
+        ds_clear(&match);
+        ds_put_format(&match, "ip6.dst == %s && udp.dst == 3784",
+                      ds_cstr(&ip_list));
+        ovn_lflow_add_with_hint(lflows, op->od, S_ROUTER_IN_IP_INPUT, 110,
+                                ds_cstr(&match), "handle_bfd_msg(); ",
+                                &op->nbrp->header_);
+    }
+
+    ds_destroy(&ip_list);
+    ds_destroy(&match);
+}
+
 /* Logical router ingress Table 0: L2 Admission Control
  * Generic admission control flows (without inport check).
  */
@@ -10614,6 +10680,9 @@ build_lrouter_ipv4_ip_input(struct ovn_port *op,
                                     &op->nbrp->header_);
         }
 
+        /* BFD msg handling */
+        build_lrouter_bfd_flows(lflows, op);
+
         /* ICMP time exceeded */
         for (int i = 0; i < op->lrp_networks.n_ipv4_addrs; i++) {
             ds_clear(match);
@@ -12724,7 +12793,7 @@ ovnnb_db_run(struct northd_context *ctx,
     build_ip_mcast(ctx, datapaths);
     build_mcast_groups(ctx, datapaths, ports, &mcast_groups, &igmp_groups);
     build_meter_groups(ctx, &meter_groups);
-    build_bfd_table(ctx, &bfd_connections);
+    build_bfd_table(ctx, &bfd_connections, ports);
     build_lflows(ctx, datapaths, ports, &port_groups, &mcast_groups,
                  &igmp_groups, &meter_groups, &lbs);
     ovn_update_ipv6_prefix(ports);
diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
index ce6c44db4..eee004328 100644
--- a/tests/ovn-northd.at
+++ b/tests/ovn-northd.at
@@ -2322,3 +2322,58 @@ sed 's/reg8\[[0..15\]] == [[0-9]]*/reg8\[[0..15\]] == <cleared>/' | sort], [0],
 ])
 
 AT_CLEANUP
+
+AT_SETUP([ovn -- check BFD config propagation to SBDB])
+AT_KEYWORDS([northd-bfd])
+ovn_start
+
+check ovn-nbctl --wait=sb lr-add r0
+for i in $(seq 1 4); do
+    check ovn-nbctl --wait=sb lrp-add r0 r0-sw$i 00:00:00:00:00:0$i 192.168.$i.1/24
+    check ovn-nbctl --wait=sb ls-add sw$i
+    check ovn-nbctl --wait=sb lsp-add sw$i sw$i-r0
+    check ovn-nbctl --wait=sb lsp-set-type sw$i-r0 router
+    check ovn-nbctl --wait=sb lsp-set-options sw$i-r0 router-port=r0-sw$i
+    check ovn-nbctl --wait=sb lsp-set-addresses sw$i-r0 00:00:00:00:00:0$i
+done
+
+uuid=$(ovn-nbctl create bfd logical_port=r0-sw1 dst_ip=192.168.10.2 status=down min_tx=250 min_rx=250 detect_mult=10)
+ovn-nbctl create bfd logical_port=r0-sw2 dst_ip=192.168.20.2 status=down min_tx=500 min_rx=500 detect_mult=20
+ovn-nbctl create bfd logical_port=r0-sw3 dst_ip=192.168.30.2 status=down
+ovn-nbctl create bfd logical_port=r0-sw4 dst_ip=192.168.40.2 status=down min_tx=0 detect_mult=0
+
+check_column 10 bfd detect_mult logical_port=r0-sw1
+check_column "192.168.10.2" bfd dst_ip logical_port=r0-sw1
+check_column 250 bfd min_rx logical_port=r0-sw1
+check_column 250 bfd min_tx logical_port=r0-sw1
+check_column admin_down bfd status logical_port=r0-sw1
+
+check_column 20 bfd detect_mult logical_port=r0-sw2
+check_column "192.168.20.2" bfd dst_ip logical_port=r0-sw2
+check_column 500 bfd min_rx logical_port=r0-sw2
+check_column 500 bfd min_tx logical_port=r0-sw2
+check_column admin_down bfd status logical_port=r0-sw2
+
+check_column 5 bfd detect_mult logical_port=r0-sw3
+check_column "192.168.30.2" bfd dst_ip logical_port=r0-sw3
+check_column 1000 bfd min_rx logical_port=r0-sw3
+check_column 1000 bfd min_tx logical_port=r0-sw3
+check_column admin_down bfd status logical_port=r0-sw3
+
+uuid=$(fetch_column nb:bfd _uuid logical_port=r0-sw1)
+check ovn-nbctl set bfd $uuid min_tx=1000
+check ovn-nbctl set bfd $uuid min_rx=1000
+check ovn-nbctl set bfd $uuid detect_mult=100
+
+uuid_2=$(fetch_column nb:bfd _uuid logical_port=r0-sw2)
+check ovn-nbctl clear bfd $uuid_2 min_rx
+check_column 1000 bfd min_rx logical_port=r0-sw2
+
+check_column 1000 bfd min_tx logical_port=r0-sw1
+check_column 1000 bfd min_rx logical_port=r0-sw1
+check_column 100 bfd detect_mult logical_port=r0-sw1
+
+ovn-nbctl destroy bfd $uuid
+check_row_count bfd 2
+
+AT_CLEANUP
-- 
2.29.2