bfd: add support for multihop

Type: feature

Change-Id: If23f9cc9317e7528f3c8d66303457206843a12c5
Signed-off-by: Abdel Baig <abdbaig@cisco.com>

8 files changed, 599 insertions, 294 deletions

diff --git a/src/vnet/bfd/bfd.api b/src/vnet/bfd/bfd.api
index d3b3ed21a26..cf14455f391 100644
--- a/src/vnet/bfd/bfd.api
+++ b/src/vnet/bfd/bfd.api
@@ -359,6 +359,16 @@ autoreply define bfd_udp_auth_deactivate
   bool is_delayed;
 };
 
+/** \brief BFD UDP - enable multihop support
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+*/
+autoreply define bfd_udp_enable_multihop
+{
+  u32 client_index;
+  u32 context;
+};
+
 /* must be compatible with bfd_error_t */
 counters bfd_udp {
   none {
diff --git a/src/vnet/bfd/bfd_api.c b/src/vnet/bfd/bfd_api.c
index 816e71081ff..bccf58ba4bb 100644
--- a/src/vnet/bfd/bfd_api.c
+++ b/src/vnet/bfd/bfd_api.c
@@ -46,8 +46,24 @@ pub_sub_handler (bfd_events, BFD_EVENTS);
   ip_address_decode(&mp->local_addr, &local_addr);                             \
   ip_address_decode(&mp->peer_addr, &peer_addr);
 
-#define BFD_UDP_API_PARAM_FROM_MP(mp) \
-  clib_net_to_host_u32 (mp->sw_if_index), &local_addr, &peer_addr
+#define BFD_UDP_API_PARAM_IS_MH(mp)                                           \
+  bfd_main.multihop_enabled && (mp->sw_if_index == ~0)
+
+#define BFD_UDP_API_PARAM_FROM_MP(mp)                                         \
+  BFD_UDP_API_PARAM_IS_MH (mp) ? true : false,                                \
+    BFD_UDP_API_PARAM_IS_MH (mp) ? ~0 :                                       \
+				   clib_net_to_host_u32 (mp->sw_if_index),    \
+    &local_addr, &peer_addr
+
+#define COND_VALIDATE_SW_IF_INDEX(mp)                                         \
+  do                                                                          \
+    {                                                                         \
+      if (!(bfd_main.multihop_enabled && mp->sw_if_index == ~0))              \
+	{                                                                     \
+	  VALIDATE_SW_IF_INDEX (mp)                                           \
+	}                                                                     \
+    }                                                                         \
+  while (0);
 
 static void
 vl_api_bfd_udp_add_t_handler (vl_api_bfd_udp_add_t * mp)
@@ -55,7 +71,7 @@ vl_api_bfd_udp_add_t_handler (vl_api_bfd_udp_add_t * mp)
   vl_api_bfd_udp_add_reply_t *rmp;
   int rv;
 
-  VALIDATE_SW_IF_INDEX (mp);
+  COND_VALIDATE_SW_IF_INDEX (mp);
 
   BFD_UDP_API_PARAM_COMMON_CODE;
 
@@ -76,7 +92,7 @@ vl_api_bfd_udp_upd_t_handler (vl_api_bfd_udp_add_t *mp)
   vl_api_bfd_udp_upd_reply_t *rmp;
   int rv;
 
-  VALIDATE_SW_IF_INDEX (mp);
+  COND_VALIDATE_SW_IF_INDEX (mp);
 
   BFD_UDP_API_PARAM_COMMON_CODE;
 
@@ -97,7 +113,7 @@ vl_api_bfd_udp_mod_t_handler (vl_api_bfd_udp_mod_t * mp)
   vl_api_bfd_udp_mod_reply_t *rmp;
   int rv;
 
-  VALIDATE_SW_IF_INDEX (mp);
+  COND_VALIDATE_SW_IF_INDEX (mp);
 
   BFD_UDP_API_PARAM_COMMON_CODE;
 
@@ -116,7 +132,7 @@ vl_api_bfd_udp_del_t_handler (vl_api_bfd_udp_del_t * mp)
   vl_api_bfd_udp_del_reply_t *rmp;
   int rv;
 
-  VALIDATE_SW_IF_INDEX (mp);
+  COND_VALIDATE_SW_IF_INDEX (mp);
 
   BFD_UDP_API_PARAM_COMMON_CODE;
 
@@ -143,7 +159,14 @@ send_bfd_udp_session_details (vl_api_registration_t * reg, u32 context,
   mp->state = clib_host_to_net_u32 (bs->local_state);
   bfd_udp_session_t *bus = &bs->udp;
   bfd_udp_key_t *key = &bus->key;
-  mp->sw_if_index = clib_host_to_net_u32 (key->sw_if_index);
+  if (bs->hop_type == BFD_HOP_TYPE_MULTI)
+    {
+      mp->sw_if_index = ~0;
+    }
+  else
+    {
+      mp->sw_if_index = clib_host_to_net_u32 (key->sw_if_index);
+    }
   if ((!bs->auth.is_delayed && bs->auth.curr_key) ||
       (bs->auth.is_delayed && bs->auth.next_key))
     {
@@ -186,7 +209,14 @@ send_bfd_udp_session_event (vl_api_registration_t *reg, u32 pid,
   mp->state = clib_host_to_net_u32 (bs->local_state);
   bfd_udp_session_t *bus = &bs->udp;
   bfd_udp_key_t *key = &bus->key;
-  mp->sw_if_index = clib_host_to_net_u32 (key->sw_if_index);
+  if (bs->hop_type == BFD_HOP_TYPE_MULTI)
+    {
+      mp->sw_if_index = ~0;
+    }
+  else
+    {
+      mp->sw_if_index = clib_host_to_net_u32 (key->sw_if_index);
+    }
   if ((!bs->auth.is_delayed && bs->auth.curr_key) ||
       (bs->auth.is_delayed && bs->auth.next_key))
     {
@@ -315,7 +345,7 @@ vl_api_bfd_udp_auth_activate_t_handler (vl_api_bfd_udp_auth_activate_t * mp)
   vl_api_bfd_udp_auth_activate_reply_t *rmp;
   int rv;
 
-  VALIDATE_SW_IF_INDEX (mp);
+  COND_VALIDATE_SW_IF_INDEX (mp);
 
   BFD_UDP_API_PARAM_COMMON_CODE;
 
@@ -334,7 +364,7 @@ vl_api_bfd_udp_auth_deactivate_t_handler (vl_api_bfd_udp_auth_deactivate_t *
   vl_api_bfd_udp_auth_deactivate_reply_t *rmp;
   int rv;
 
-  VALIDATE_SW_IF_INDEX (mp);
+  COND_VALIDATE_SW_IF_INDEX (mp);
 
   BFD_UDP_API_PARAM_COMMON_CODE;
 
@@ -423,6 +453,17 @@ vl_api_bfd_udp_get_echo_source_t_handler (vl_api_bfd_udp_get_echo_source_t *
   }))
 }
 
+static void
+vl_api_bfd_udp_enable_multihop_t_handler (vl_api_bfd_udp_enable_multihop_t *mp)
+{
+  vl_api_bfd_udp_enable_multihop_reply_t *rmp;
+  int rv = 0;
+
+  bfd_main.multihop_enabled = true;
+
+  REPLY_MACRO (VL_API_BFD_UDP_ENABLE_MULTIHOP_REPLY);
+}
+
 #include <vnet/bfd/bfd.api.c>
 static clib_error_t *
 bfd_api_hookup (vlib_main_t * vm)
diff --git a/src/vnet/bfd/bfd_api.h b/src/vnet/bfd/bfd_api.h
index f051e6b679c..16501fcd272 100644
--- a/src/vnet/bfd/bfd_api.h
+++ b/src/vnet/bfd/bfd_api.h
@@ -37,44 +37,49 @@ typedef enum
 /**
  * @brief create a new bfd session
  */
-vnet_api_error_t
-bfd_udp_add_session (u32 sw_if_index, const ip46_address_t * local_addr,
-		     const ip46_address_t * peer_addr,
-		     u32 desired_min_tx_usec, u32 required_min_rx_usec,
-		     u8 detect_mult, u8 is_authenticated, u32 conf_key_id,
-		     u8 bfd_key_id);
+vnet_api_error_t bfd_udp_add_session (bool multihop, u32 sw_if_index,
+				      const ip46_address_t *local_addr,
+				      const ip46_address_t *peer_addr,
+				      u32 desired_min_tx_usec,
+				      u32 required_min_rx_usec, u8 detect_mult,
+				      u8 is_authenticated, u32 conf_key_id,
+				      u8 bfd_key_id);
 
 /**
- * @brief create a new or modify and existing bfd session
+ * @brief create a new or modify an existing bfd session
  */
-vnet_api_error_t
-bfd_udp_upd_session (u32 sw_if_index, const ip46_address_t *local_addr,
-		     const ip46_address_t *peer_addr, u32 desired_min_tx_usec,
-		     u32 required_min_rx_usec, u8 detect_mult,
-		     u8 is_authenticated, u32 conf_key_id, u8 bfd_key_id);
+vnet_api_error_t bfd_udp_upd_session (bool multihop, u32 sw_if_index,
+				      const ip46_address_t *local_addr,
+				      const ip46_address_t *peer_addr,
+				      u32 desired_min_tx_usec,
+				      u32 required_min_rx_usec, u8 detect_mult,
+				      u8 is_authenticated, u32 conf_key_id,
+				      u8 bfd_key_id);
 
 /**
  * @brief modify existing session
  */
-vnet_api_error_t
-bfd_udp_mod_session (u32 sw_if_index, const ip46_address_t * local_addr,
-		     const ip46_address_t * peer_addr,
-		     u32 desired_min_tx_usec, u32 required_min_rx_usec,
-		     u8 detect_mult);
+vnet_api_error_t bfd_udp_mod_session (bool multihop, u32 sw_if_index,
+				      const ip46_address_t *local_addr,
+				      const ip46_address_t *peer_addr,
+				      u32 desired_min_tx_usec,
+				      u32 required_min_rx_usec,
+				      u8 detect_mult);
 
 /**
  * @brief delete existing session
  */
-vnet_api_error_t bfd_udp_del_session (u32 sw_if_index,
-				      const ip46_address_t * local_addr,
-				      const ip46_address_t * peer_addr);
+vnet_api_error_t bfd_udp_del_session (bool multihop, u32 sw_if_index,
+				      const ip46_address_t *local_addr,
+				      const ip46_address_t *peer_addr);
 
 /**
  * @brief set session admin down/up
  */
-vnet_api_error_t bfd_udp_session_set_flags (vlib_main_t * vm, u32 sw_if_index,
-					    const ip46_address_t * local_addr,
-					    const ip46_address_t * peer_addr,
+vnet_api_error_t bfd_udp_session_set_flags (vlib_main_t *vm, bool multihop,
+					    u32 sw_if_index,
+					    const ip46_address_t *local_addr,
+					    const ip46_address_t *peer_addr,
 					    u8 admin_up_down);
 
 /**
@@ -91,18 +96,18 @@ vnet_api_error_t bfd_auth_del_key (u32 conf_key_id);
 /**
  * @brief activate authentication for existing session
  */
-vnet_api_error_t bfd_udp_auth_activate (u32 sw_if_index,
-					const ip46_address_t * local_addr,
-					const ip46_address_t * peer_addr,
+vnet_api_error_t bfd_udp_auth_activate (bool multihop, u32 sw_if_index,
+					const ip46_address_t *local_addr,
+					const ip46_address_t *peer_addr,
 					u32 conf_key_id, u8 bfd_key_id,
 					u8 is_delayed);
 
 /**
  * @brief deactivate authentication for existing session
  */
-vnet_api_error_t bfd_udp_auth_deactivate (u32 sw_if_index,
-					  const ip46_address_t * local_addr,
-					  const ip46_address_t * peer_addr,
+vnet_api_error_t bfd_udp_auth_deactivate (bool multihop, u32 sw_if_index,
+					  const ip46_address_t *local_addr,
+					  const ip46_address_t *peer_addr,
 					  u8 is_delayed);
 
 /**
diff --git a/src/vnet/bfd/bfd_cli.c b/src/vnet/bfd/bfd_cli.c
index 33942bb89e6..194c62b507c 100644
--- a/src/vnet/bfd/bfd_cli.c
+++ b/src/vnet/bfd/bfd_cli.c
@@ -26,11 +26,39 @@
 #include <vnet/bfd/bfd_api.h>
 #include <vnet/bfd/bfd_main.h>
 
+#define BFD_MULTIHOP_CLI_CHECK                                                \
+  do                                                                          \
+    {                                                                         \
+      multihop = have_multihop;                                               \
+      if (multihop)                                                           \
+	{                                                                     \
+	  sw_if_index = ~0;                                                   \
+	}                                                                     \
+      if (multihop && have_sw_if_index)                                       \
+	{                                                                     \
+	  ret = clib_error_return (                                           \
+	    0, "Incompatible parameter combination, "                         \
+	       "interface cannot be specified when multihop is enabled");     \
+	  goto out;                                                           \
+	}                                                                     \
+      if (!multihop && !have_sw_if_index)                                     \
+	{                                                                     \
+	  ret =                                                               \
+	    clib_error_return (0, "Incompatible parameter combination, "      \
+				  "interface must be set if not multihop");   \
+	  goto out;                                                           \
+	}                                                                     \
+    }                                                                         \
+  while (0);
+
 static u8 *
 format_bfd_session_cli (u8 * s, va_list * args)
 {
   vlib_main_t *vm = va_arg (*args, vlib_main_t *);
   bfd_session_t *bs = va_arg (*args, bfd_session_t *);
+  s = format (s, "%10s %-32s %20s\n", "", "Hop Type",
+	      bfd_hop_type_string (bs->hop_type));
+
   switch (bs->transport)
     {
     case BFD_TRANSPORT_UDP4:
@@ -52,6 +80,8 @@ format_bfd_session_cli (u8 * s, va_list * args)
 	      bfd_diag_code_string (bs->remote_diag));
   s = format (s, "%10s %-32s %20u %20u\n", "", "Detect multiplier",
 	      bs->local_detect_mult, bs->remote_detect_mult);
+  s = format (s, "%10s %-32s %20llu\n", "", "Detection Time (usec)",
+	      bfd_nsec_to_usec (bs->detection_time_nsec));
   s = format (s, "%10s %-32s %20u %20llu\n", "",
 	      "Required Min Rx Interval (usec)",
 	      bs->config_required_min_rx_usec, bs->remote_min_rx_usec);
@@ -363,6 +393,7 @@ VLIB_CLI_COMMAND (bfd_cli_key_del_command, static) = {
 #define DETECT_MULT_STR "detect-mult"
 #define ADMIN_STR "admin"
 #define DELAYED_STR "delayed"
+#define MULTIHOP_STR	    "multihop"
 
 static const unsigned mandatory = 1;
 static const unsigned optional = 0;
@@ -401,7 +432,8 @@ bfd_cli_udp_session_add (vlib_main_t * vm, unformat_input_t * input,
   clib_error_t *ret = NULL;
   unformat_input_t _line_input, *line_input = &_line_input;
 #define foreach_bfd_cli_udp_session_add_cli_param(F)                          \
-  F (u32, sw_if_index, INTERFACE_STR, mandatory, "%U",                        \
+  F (bool, multihop, MULTIHOP_STR, optional, "%_")                            \
+  F (u32, sw_if_index, INTERFACE_STR, optional, "%U",                         \
      unformat_vnet_sw_interface, &vnet_main)                                  \
   F (ip46_address_t, local_addr, LOCAL_ADDR_STR, mandatory, "%U",             \
      bfd_cli_unformat_ip46_address)                                           \
@@ -433,6 +465,7 @@ bfd_cli_udp_session_add (vlib_main_t * vm, unformat_input_t * input,
     }
 
   foreach_bfd_cli_udp_session_add_cli_param (CHECK_MANDATORY);
+  BFD_MULTIHOP_CLI_CHECK
 
   if (1 == have_conf_key_id + have_bfd_key_id)
     {
@@ -456,11 +489,9 @@ bfd_cli_udp_session_add (vlib_main_t * vm, unformat_input_t * input,
       goto out;
     }
 
-  vnet_api_error_t rv =
-    bfd_udp_add_session (sw_if_index, &local_addr, &peer_addr, desired_min_tx,
-			 required_min_rx,
-			 detect_mult, have_conf_key_id, conf_key_id,
-			 bfd_key_id);
+  vnet_api_error_t rv = bfd_udp_add_session (
+    multihop, sw_if_index, &local_addr, &peer_addr, desired_min_tx,
+    required_min_rx, detect_mult, have_conf_key_id, conf_key_id, bfd_key_id);
   if (rv)
     {
       ret =
@@ -477,16 +508,16 @@ out:
 VLIB_CLI_COMMAND (bfd_cli_udp_session_add_command, static) = {
   .path = "bfd udp session add",
   .short_help = "bfd udp session add"
-                " interface <interface>"
-                " local-addr <local-address>"
-                " peer-addr <peer-address>"
-                " desired-min-tx <desired min tx interval>"
-                " required-min-rx <required min rx interval>"
-                " detect-mult <detect multiplier> "
-                "["
-                " conf-key-id <config key ID>"
-                " bfd-key-id <BFD key ID>"
-                "]",
+		" <multihop | interface <interface>>"
+		" local-addr <local-address>"
+		" peer-addr <peer-address>"
+		" desired-min-tx <desired min tx interval>"
+		" required-min-rx <required min rx interval>"
+		" detect-mult <detect multiplier> "
+		"["
+		" conf-key-id <config key ID>"
+		" bfd-key-id <BFD key ID>"
+		"]",
   .function = bfd_cli_udp_session_add,
 };
 
@@ -497,7 +528,8 @@ bfd_cli_udp_session_mod (vlib_main_t * vm, unformat_input_t * input,
   clib_error_t *ret = NULL;
   unformat_input_t _line_input, *line_input = &_line_input;
 #define foreach_bfd_cli_udp_session_mod_cli_param(F)                          \
-  F (u32, sw_if_index, INTERFACE_STR, mandatory, "%U",                        \
+  F (bool, multihop, MULTIHOP_STR, optional, "%_")                            \
+  F (u32, sw_if_index, INTERFACE_STR, optional, "%U",                         \
      unformat_vnet_sw_interface, &vnet_main)                                  \
   F (ip46_address_t, local_addr, LOCAL_ADDR_STR, mandatory, "%U",             \
      bfd_cli_unformat_ip46_address)                                           \
@@ -527,6 +559,7 @@ bfd_cli_udp_session_mod (vlib_main_t * vm, unformat_input_t * input,
     }
 
   foreach_bfd_cli_udp_session_mod_cli_param (CHECK_MANDATORY);
+  BFD_MULTIHOP_CLI_CHECK
 
   if (detect_mult > 255)
     {
@@ -536,7 +569,7 @@ bfd_cli_udp_session_mod (vlib_main_t * vm, unformat_input_t * input,
     }
 
   vnet_api_error_t rv =
-    bfd_udp_mod_session (sw_if_index, &local_addr, &peer_addr,
+    bfd_udp_mod_session (multihop, sw_if_index, &local_addr, &peer_addr,
 			 desired_min_tx, required_min_rx, detect_mult);
   if (rv)
     {
@@ -553,13 +586,13 @@ out:
 
 VLIB_CLI_COMMAND (bfd_cli_udp_session_mod_command, static) = {
   .path = "bfd udp session mod",
-  .short_help = "bfd udp session mod interface"
-                " <interface> local-addr"
-                " <local-address> peer-addr"
-                " <peer-address> desired-min-tx"
-                " <desired min tx interval> required-min-rx"
-                " <required min rx interval> detect-mult"
-                " <detect multiplier> ",
+  .short_help = "bfd udp session mod "
+		" <multihop | interface <interface>>"
+		" <local-address> peer-addr"
+		" <peer-address> desired-min-tx"
+		" <desired min tx interval> required-min-rx"
+		" <required min rx interval> detect-mult"
+		" <detect multiplier> ",
   .function = bfd_cli_udp_session_mod,
 };
 
@@ -570,7 +603,8 @@ bfd_cli_udp_session_del (vlib_main_t * vm, unformat_input_t * input,
   clib_error_t *ret = NULL;
   unformat_input_t _line_input, *line_input = &_line_input;
 #define foreach_bfd_cli_udp_session_del_cli_param(F)                          \
-  F (u32, sw_if_index, INTERFACE_STR, mandatory, "%U",                        \
+  F (bool, multihop, MULTIHOP_STR, optional, "%_")                            \
+  F (u32, sw_if_index, INTERFACE_STR, optional, "%U",                         \
      unformat_vnet_sw_interface, &vnet_main)                                  \
   F (ip46_address_t, local_addr, LOCAL_ADDR_STR, mandatory, "%U",             \
      bfd_cli_unformat_ip46_address)                                           \
@@ -597,9 +631,10 @@ bfd_cli_udp_session_del (vlib_main_t * vm, unformat_input_t * input,
     }
 
   foreach_bfd_cli_udp_session_del_cli_param (CHECK_MANDATORY);
+  BFD_MULTIHOP_CLI_CHECK
 
   vnet_api_error_t rv =
-    bfd_udp_del_session (sw_if_index, &local_addr, &peer_addr);
+    bfd_udp_del_session (multihop, sw_if_index, &local_addr, &peer_addr);
   if (rv)
     {
       ret =
@@ -615,10 +650,10 @@ out:
 
 VLIB_CLI_COMMAND (bfd_cli_udp_session_del_command, static) = {
   .path = "bfd udp session del",
-  .short_help = "bfd udp session del interface"
-                " <interface> local-addr"
-                " <local-address> peer-addr"
-                "<peer-address> ",
+  .short_help = "bfd udp session del <multihop |"
+		" interface <interface>> local-addr"
+		" <local-address> peer-addr"
+		"<peer-address> ",
   .function = bfd_cli_udp_session_del,
 };
 
@@ -629,7 +664,8 @@ bfd_cli_udp_session_set_flags (vlib_main_t * vm, unformat_input_t * input,
   clib_error_t *ret = NULL;
   unformat_input_t _line_input, *line_input = &_line_input;
 #define foreach_bfd_cli_udp_session_set_flags_cli_param(F)                    \
-  F (u32, sw_if_index, INTERFACE_STR, mandatory, "%U",                        \
+  F (bool, multihop, MULTIHOP_STR, optional, "%_")                            \
+  F (u32, sw_if_index, INTERFACE_STR, optional, "%U",                         \
      unformat_vnet_sw_interface, &vnet_main)                                  \
   F (ip46_address_t, local_addr, LOCAL_ADDR_STR, mandatory, "%U",             \
      bfd_cli_unformat_ip46_address)                                           \
@@ -658,6 +694,7 @@ bfd_cli_udp_session_set_flags (vlib_main_t * vm, unformat_input_t * input,
     }
 
   foreach_bfd_cli_udp_session_set_flags_cli_param (CHECK_MANDATORY);
+  BFD_MULTIHOP_CLI_CHECK
 
   u8 admin_up_down;
   static const char up[] = "up";
@@ -677,9 +714,8 @@ bfd_cli_udp_session_set_flags (vlib_main_t * vm, unformat_input_t * input,
 			   ADMIN_STR, admin_up_down_token);
       goto out;
     }
-  vnet_api_error_t rv =
-    bfd_udp_session_set_flags (vm, sw_if_index, &local_addr,
-			       &peer_addr, admin_up_down);
+  vnet_api_error_t rv = bfd_udp_session_set_flags (
+    vm, multihop, sw_if_index, &local_addr, &peer_addr, admin_up_down);
   if (rv)
     {
       ret =
@@ -696,10 +732,10 @@ out:
 VLIB_CLI_COMMAND (bfd_cli_udp_session_set_flags_command, static) = {
   .path = "bfd udp session set-flags",
   .short_help = "bfd udp session set-flags"
-                " interface <interface>"
-                " local-addr <local-address>"
-                " peer-addr <peer-address>"
-                " admin <up|down>",
+		" <multihop | interface <interface>>"
+		" local-addr <local-address>"
+		" peer-addr <peer-address>"
+		" admin <up|down>",
   .function = bfd_cli_udp_session_set_flags,
 };
 
@@ -711,7 +747,8 @@ bfd_cli_udp_session_auth_activate (vlib_main_t * vm,
   clib_error_t *ret = NULL;
   unformat_input_t _line_input, *line_input = &_line_input;
 #define foreach_bfd_cli_udp_session_auth_activate_cli_param(F)                \
-  F (u32, sw_if_index, INTERFACE_STR, mandatory, "%U",                        \
+  F (bool, multihop, MULTIHOP_STR, optional, "%_")                            \
+  F (u32, sw_if_index, INTERFACE_STR, optional, "%U",                         \
      unformat_vnet_sw_interface, &vnet_main)                                  \
   F (ip46_address_t, local_addr, LOCAL_ADDR_STR, mandatory, "%U",             \
      bfd_cli_unformat_ip46_address)                                           \
@@ -741,6 +778,7 @@ bfd_cli_udp_session_auth_activate (vlib_main_t * vm,
     }
 
   foreach_bfd_cli_udp_session_auth_activate_cli_param (CHECK_MANDATORY);
+  BFD_MULTIHOP_CLI_CHECK
 
   u8 is_delayed = 0;
   if (have_delayed_token)
@@ -773,8 +811,8 @@ bfd_cli_udp_session_auth_activate (vlib_main_t * vm,
     }
 
   vnet_api_error_t rv =
-    bfd_udp_auth_activate (sw_if_index, &local_addr, &peer_addr, conf_key_id,
-			   bfd_key_id, is_delayed);
+    bfd_udp_auth_activate (multihop, sw_if_index, &local_addr, &peer_addr,
+			   conf_key_id, bfd_key_id, is_delayed);
   if (rv)
     {
       ret =
@@ -791,12 +829,12 @@ out:
 VLIB_CLI_COMMAND (bfd_cli_udp_session_auth_activate_command, static) = {
   .path = "bfd udp session auth activate",
   .short_help = "bfd udp session auth activate"
-                " interface <interface>"
-                " local-addr <local-address>"
-                " peer-addr <peer-address>"
-                " conf-key-id <config key ID>"
-                " bfd-key-id <BFD key ID>"
-                " [ delayed <yes|no> ]",
+		" <multihop | interface <interface>>"
+		" local-addr <local-address>"
+		" peer-addr <peer-address>"
+		" conf-key-id <config key ID>"
+		" bfd-key-id <BFD key ID>"
+		" [ delayed <yes|no> ]",
   .function = bfd_cli_udp_session_auth_activate,
 };
 
@@ -807,7 +845,8 @@ bfd_cli_udp_session_auth_deactivate (vlib_main_t *vm, unformat_input_t *input,
   clib_error_t *ret = NULL;
   unformat_input_t _line_input, *line_input = &_line_input;
 #define foreach_bfd_cli_udp_session_auth_deactivate_cli_param(F)              \
-  F (u32, sw_if_index, INTERFACE_STR, mandatory, "%U",                        \
+  F (bool, multihop, MULTIHOP_STR, optional, "%_")                            \
+  F (u32, sw_if_index, INTERFACE_STR, optional, "%U",                         \
      unformat_vnet_sw_interface, &vnet_main)                                  \
   F (ip46_address_t, local_addr, LOCAL_ADDR_STR, mandatory, "%U",             \
      bfd_cli_unformat_ip46_address)                                           \
@@ -835,6 +874,7 @@ bfd_cli_udp_session_auth_deactivate (vlib_main_t *vm, unformat_input_t *input,
     }
 
   foreach_bfd_cli_udp_session_auth_deactivate_cli_param (CHECK_MANDATORY);
+  BFD_MULTIHOP_CLI_CHECK
 
   u8 is_delayed = 0;
   if (have_delayed_token)
@@ -858,8 +898,8 @@ bfd_cli_udp_session_auth_deactivate (vlib_main_t *vm, unformat_input_t *input,
         }
     }
 
-  vnet_api_error_t rv = bfd_udp_auth_deactivate (sw_if_index, &local_addr,
-                                                 &peer_addr, is_delayed);
+  vnet_api_error_t rv = bfd_udp_auth_deactivate (
+    multihop, sw_if_index, &local_addr, &peer_addr, is_delayed);
   if (rv)
     {
       ret = clib_error_return (
@@ -875,10 +915,10 @@ out:
 VLIB_CLI_COMMAND (bfd_cli_udp_session_auth_deactivate_command, static) = {
   .path = "bfd udp session auth deactivate",
   .short_help = "bfd udp session auth deactivate"
-                " interface <interface>"
-                " local-addr <local-address>"
-                " peer-addr <peer-address>"
-                "[ delayed <yes|no> ]",
+		" <multihop | interface <interface>>"
+		" local-addr <local-address>"
+		" peer-addr <peer-address>"
+		"[ delayed <yes|no> ]",
   .function = bfd_cli_udp_session_auth_deactivate,
 };
 
diff --git a/src/vnet/bfd/bfd_main.c b/src/vnet/bfd/bfd_main.c
index 1423da91158..4ad0a16830f 100644
--- a/src/vnet/bfd/bfd_main.c
+++ b/src/vnet/bfd/bfd_main.c
@@ -30,6 +30,20 @@
 #include <vlib/log.h>
 #include <vnet/crypto/crypto.h>
 
+const char *
+bfd_hop_type_string (bfd_hop_type_e hoptype)
+{
+  switch (hoptype)
+    {
+#define F(x)                                                                  \
+  case BFD_HOP_TYPE_##x:                                                      \
+    return "BFD_HOP_TYPE_" #x;
+      foreach_bfd_hop (F)
+#undef F
+    }
+  return "UNKNOWN";
+}
+
 static void
 bfd_validate_counters (bfd_main_t *bm)
 {
@@ -1353,6 +1367,8 @@ VLIB_REGISTER_NODE (bfd_process_node, static) =
     [BFD_TX_IP6_REWRITE] = "ip6-rewrite",
     [BFD_TX_IP4_MIDCHAIN] = "ip4-midchain",
     [BFD_TX_IP6_MIDCHAIN] = "ip6-midchain",
+    [BFD_TX_IP4_LOOKUP] = "ip4-lookup",
+    [BFD_TX_IP6_LOOKUP] = "ip6-lookup",
   }
 };
 // clang-format on
@@ -2049,29 +2065,29 @@ u8 *
 format_bfd_session (u8 * s, va_list * args)
 {
   const bfd_session_t *bs = va_arg (*args, bfd_session_t *);
-  s = format (s, "bs_idx=%u local-state=%s remote-state=%s\n"
-	      "local-discriminator=%u remote-discriminator=%u\n"
-	      "local-diag=%s echo-active=%s\n"
-	      "desired-min-tx=%u required-min-rx=%u\n"
-	      "required-min-echo-rx=%u detect-mult=%u\n"
-	      "remote-min-rx=%u remote-min-echo-rx=%u\n"
-	      "remote-demand=%s poll-state=%s\n"
-	      "auth: local-seq-num=%u remote-seq-num=%u\n"
-	      "      is-delayed=%s\n"
-	      "      curr-key=%U\n"
-	      "      next-key=%U",
-	      bs->bs_idx, bfd_state_string (bs->local_state),
-	      bfd_state_string (bs->remote_state), bs->local_discr,
-	      bs->remote_discr, bfd_diag_code_string (bs->local_diag),
-	      (bs->echo ? "yes" : "no"), bs->config_desired_min_tx_usec,
-	      bs->config_required_min_rx_usec, 1, bs->local_detect_mult,
-	      bs->remote_min_rx_usec, bs->remote_min_echo_rx_usec,
-	      (bs->remote_demand ? "yes" : "no"),
-	      bfd_poll_state_string (bs->poll_state),
-	      bs->auth.local_seq_number, bs->auth.remote_seq_number,
-	      (bs->auth.is_delayed ? "yes" : "no"),
-	      format_bfd_auth_key, bs->auth.curr_key, format_bfd_auth_key,
-	      bs->auth.next_key);
+  s = format (
+    s,
+    "bs_idx=%u hop-type=%s local-state=%s remote-state=%s\n"
+    "local-discriminator=%u remote-discriminator=%u\n"
+    "local-diag=%s echo-active=%s\n"
+    "desired-min-tx=%u required-min-rx=%u\n"
+    "required-min-echo-rx=%u detect-mult=%u\n"
+    "remote-min-rx=%u remote-min-echo-rx=%u\n"
+    "remote-demand=%s poll-state=%s\n"
+    "auth: local-seq-num=%u remote-seq-num=%u\n"
+    "      is-delayed=%s\n"
+    "      curr-key=%U\n"
+    "      next-key=%U",
+    bs->bs_idx, bfd_hop_type_string (bs->hop_type),
+    bfd_state_string (bs->local_state), bfd_state_string (bs->remote_state),
+    bs->local_discr, bs->remote_discr, bfd_diag_code_string (bs->local_diag),
+    (bs->echo ? "yes" : "no"), bs->config_desired_min_tx_usec,
+    bs->config_required_min_rx_usec, 1, bs->local_detect_mult,
+    bs->remote_min_rx_usec, bs->remote_min_echo_rx_usec,
+    (bs->remote_demand ? "yes" : "no"), bfd_poll_state_string (bs->poll_state),
+    bs->auth.local_seq_number, bs->auth.remote_seq_number,
+    (bs->auth.is_delayed ? "yes" : "no"), format_bfd_auth_key,
+    bs->auth.curr_key, format_bfd_auth_key, bs->auth.next_key);
   return s;
 }
 
diff --git a/src/vnet/bfd/bfd_main.h b/src/vnet/bfd/bfd_main.h
index 1d4617e1d7c..7d9253983ce 100644
--- a/src/vnet/bfd/bfd_main.h
+++ b/src/vnet/bfd/bfd_main.h
@@ -71,13 +71,13 @@ typedef enum
 /**
  * hop types
  */
-#define foreach_bfd_hop(F)                     \
-  F (SINGLE, "single")                         \
-  F (MULTI,  "multi")                          \
+#define foreach_bfd_hop(F)                                                    \
+  F (SINGLE)                                                                  \
+  F (MULTI)
 
 typedef enum
 {
-#define F(sym, str) BFD_HOP_TYPE_##sym,
+#define F(sym) BFD_HOP_TYPE_##sym,
   foreach_bfd_hop (F)
 #undef F
 } bfd_hop_type_e;
@@ -318,6 +318,12 @@ typedef struct
   /** vector of callback notification functions */
   bfd_notify_fn_t *listeners;
 
+  /**
+   * true if multihop support is enabled so sw_if_index of ~0
+   * represents a multihop session
+   */
+  bool multihop_enabled;
+
   /** log class */
   vlib_log_class_t log_class;
 
@@ -449,6 +455,7 @@ vnet_api_error_t bfd_session_set_params (bfd_main_t * bm, bfd_session_t * bs,
 
 u32 bfd_nsec_to_usec (u64 nsec);
 const char *bfd_poll_state_string (bfd_poll_state_e state);
+const char *bfd_hop_type_string (bfd_hop_type_e state);
 
 #define USEC_PER_MS (1000LL)
 #define MSEC_PER_SEC (1000LL)
@@ -482,6 +489,8 @@ typedef enum
   BFD_TX_IP6_REWRITE,
   BFD_TX_IP4_MIDCHAIN,
   BFD_TX_IP6_MIDCHAIN,
+  BFD_TX_IP4_LOOKUP,
+  BFD_TX_IP6_LOOKUP,
   BFD_TX_N_NEXT,
 } bfd_tx_next_t;
 
diff --git a/src/vnet/bfd/bfd_udp.c b/src/vnet/bfd/bfd_udp.c
index ec42cda1bc4..6d3202cc55c 100644
--- a/src/vnet/bfd/bfd_udp.c
+++ b/src/vnet/bfd/bfd_udp.c
@@ -64,12 +64,18 @@ typedef struct
   u32 echo_source_sw_if_index;
   /* log class */
   vlib_log_class_t log_class;
-  /* number of active udp4 sessions */
-  u32 udp4_sessions_count;
-  u32 udp4_sessions_count_stat_seg_entry;
-  /* number of active udp6 sessions */
-  u32 udp6_sessions_count;
-  u32 udp6_sessions_count_stat_seg_entry;
+  /* number of active udp4 single-hop sessions */
+  u32 udp4_sh_sessions_count;
+  u32 udp4_sh_sessions_count_stat_seg_entry;
+  /* number of active udp6 single-hop sessions */
+  u32 udp6_sh_sessions_count;
+  u32 udp6_sh_sessions_count_stat_seg_entry;
+  /* number of active udp4 multi-hop sessions */
+  u32 udp4_mh_sessions_count;
+  u32 udp4_mh_sessions_count_stat_seg_entry;
+  /* number of active udp6 multi-hop sessions */
+  u32 udp6_mh_sessions_count;
+  u32 udp6_mh_sessions_count_stat_seg_entry;
 } bfd_udp_main_t;
 
 static vlib_node_registration_t bfd_udp4_input_node;
@@ -258,8 +264,11 @@ bfd_add_udp4_transport (vlib_main_t * vm, u32 bi, const bfd_session_t * bs,
   vlib_buffer_t *b = vlib_get_buffer (vm, bi);
 
   b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
-  vnet_buffer (b)->ip.adj_index[VLIB_RX] = bus->adj_index;
-  vnet_buffer (b)->ip.adj_index[VLIB_TX] = bus->adj_index;
+  if (bs->hop_type == BFD_HOP_TYPE_SINGLE)
+    {
+      vnet_buffer (b)->ip.adj_index[VLIB_RX] = bus->adj_index;
+      vnet_buffer (b)->ip.adj_index[VLIB_TX] = bus->adj_index;
+    }
   vnet_buffer (b)->sw_if_index[VLIB_RX] = 0;
   vnet_buffer (b)->sw_if_index[VLIB_TX] = ~0;
   typedef struct
@@ -290,7 +299,14 @@ bfd_add_udp4_transport (vlib_main_t * vm, u32 bi, const bfd_session_t * bs,
     {
       headers->ip4.src_address.as_u32 = key->local_addr.ip4.as_u32;
       headers->ip4.dst_address.as_u32 = key->peer_addr.ip4.as_u32;
-      headers->udp.dst_port = clib_host_to_net_u16 (UDP_DST_PORT_bfd4);
+      if (bs->hop_type == BFD_HOP_TYPE_MULTI)
+	{
+	  headers->udp.dst_port = clib_host_to_net_u16 (UDP_DST_PORT_bfd4_mh);
+	}
+      else
+	{
+	  headers->udp.dst_port = clib_host_to_net_u16 (UDP_DST_PORT_bfd4);
+	}
     }
 
   /* fix ip length, checksum and udp length */
@@ -313,8 +329,11 @@ bfd_add_udp6_transport (vlib_main_t * vm, u32 bi, const bfd_session_t * bs,
   vlib_buffer_t *b = vlib_get_buffer (vm, bi);
 
   b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED;
-  vnet_buffer (b)->ip.adj_index[VLIB_RX] = bus->adj_index;
-  vnet_buffer (b)->ip.adj_index[VLIB_TX] = bus->adj_index;
+  if (bs->hop_type == BFD_HOP_TYPE_SINGLE)
+    {
+      vnet_buffer (b)->ip.adj_index[VLIB_RX] = bus->adj_index;
+      vnet_buffer (b)->ip.adj_index[VLIB_TX] = bus->adj_index;
+    }
   vnet_buffer (b)->sw_if_index[VLIB_RX] = 0;
   vnet_buffer (b)->sw_if_index[VLIB_TX] = 0;
   typedef struct
@@ -350,7 +369,14 @@ bfd_add_udp6_transport (vlib_main_t * vm, u32 bi, const bfd_session_t * bs,
 			sizeof (headers->ip6.src_address));
       clib_memcpy_fast (&headers->ip6.dst_address, &key->peer_addr.ip6,
 			sizeof (headers->ip6.dst_address));
-      headers->udp.dst_port = clib_host_to_net_u16 (UDP_DST_PORT_bfd6);
+      if (bs->hop_type == BFD_HOP_TYPE_MULTI)
+	{
+	  headers->udp.dst_port = clib_host_to_net_u16 (UDP_DST_PORT_bfd6_mh);
+	}
+      else
+	{
+	  headers->udp.dst_port = clib_host_to_net_u16 (UDP_DST_PORT_bfd6);
+	}
     }
 
   /* fix ip payload length and udp length */
@@ -398,9 +424,25 @@ bfd_udp_calc_next_node (const struct bfd_session_s *bs, u32 * next_node)
 {
   vnet_main_t *vnm = vnet_get_main ();
   const bfd_udp_session_t *bus = &bs->udp;
-  ip_adjacency_t *adj = adj_get (bus->adj_index);
 
-  /* don't try to send the buffer if the interface is not up */
+  if (bs->hop_type == BFD_HOP_TYPE_MULTI)
+    {
+      switch (bs->transport)
+	{
+	case BFD_TRANSPORT_UDP4:
+	  *next_node = BFD_TX_IP4_LOOKUP;
+	  return 1;
+	case BFD_TRANSPORT_UDP6:
+	  *next_node = BFD_TX_IP6_LOOKUP;
+	  return 1;
+	default:
+	  /* drop */
+	  return 0;
+	}
+    }
+
+  ip_adjacency_t *adj = adj_get (bus->adj_index);
+  /* For single-hop, don't try to send the buffer if the interface is not up */
   if (!vnet_sw_interface_is_up (vnm, bus->key.sw_if_index))
     return 0;
 
@@ -495,7 +537,7 @@ bfd_udp_key_init (bfd_udp_key_t * key, u32 sw_if_index,
 		  const ip46_address_t * peer_addr)
 {
   clib_memset (key, 0, sizeof (*key));
-  key->sw_if_index = sw_if_index;
+  key->sw_if_index = sw_if_index & 0xFFFF;
   key->local_addr.as_u64[0] = local_addr->as_u64[0];
   key->local_addr.as_u64[1] = local_addr->as_u64[1];
   key->peer_addr.as_u64[0] = peer_addr->as_u64[0];
@@ -503,12 +545,13 @@ bfd_udp_key_init (bfd_udp_key_t * key, u32 sw_if_index,
 }
 
 static vnet_api_error_t
-bfd_udp_add_session_internal (vlib_main_t * vm, bfd_udp_main_t * bum,
-			      u32 sw_if_index, u32 desired_min_tx_usec,
+bfd_udp_add_session_internal (vlib_main_t *vm, bfd_udp_main_t *bum,
+			      bool multihop, u32 sw_if_index,
+			      u32 desired_min_tx_usec,
 			      u32 required_min_rx_usec, u8 detect_mult,
-			      const ip46_address_t * local_addr,
-			      const ip46_address_t * peer_addr,
-			      bfd_session_t ** bs_out)
+			      const ip46_address_t *local_addr,
+			      const ip46_address_t *peer_addr,
+			      bfd_session_t **bs_out)
 {
   /* get a pool entry and if we end up not needing it, give it back */
   bfd_transport_e t = BFD_TRANSPORT_UDP4;
@@ -536,8 +579,9 @@ bfd_udp_add_session_internal (vlib_main_t * vm, bfd_udp_main_t * bum,
       return VNET_API_ERROR_BFD_EEXIST;
     }
   mhash_set (&bum->bfd_session_idx_by_bfd_key, key, bs->bs_idx, NULL);
-  BFD_DBG ("session created, bs_idx=%u, sw_if_index=%d, local=%U, peer=%U",
-	   bs->bs_idx, key->sw_if_index, format_ip46_address,
+  BFD_DBG ("session created, bs_idx=%u, multihop=%u, sw_if_index=%d, "
+	   "local=%U, peer=%U",
+	   bs->bs_idx, multihop, key->sw_if_index, format_ip46_address,
 	   &key->local_addr, IP46_TYPE_ANY, format_ip46_address,
 	   &key->peer_addr, IP46_TYPE_ANY);
   vlib_log_info (bum->log_class, "create BFD session: %U",
@@ -548,41 +592,82 @@ bfd_udp_add_session_internal (vlib_main_t * vm, bfd_udp_main_t * bum,
        &key->peer_addr);
   if (BFD_TRANSPORT_UDP4 == t)
     {
-      bus->adj_index = adj_nbr_add_or_lock (FIB_PROTOCOL_IP4, VNET_LINK_IP4,
-					    peer, key->sw_if_index);
-      BFD_DBG ("adj_nbr_add_or_lock(FIB_PROTOCOL_IP4, VNET_LINK_IP4, %U, %d) "
-	       "returns %d",
-	       format_ip46_address, peer, IP46_TYPE_ANY, key->sw_if_index,
-	       bus->adj_index);
-      ++bum->udp4_sessions_count;
-      bfd_udp_update_stat_segment_entry (
-	bum->udp4_sessions_count_stat_seg_entry, bum->udp4_sessions_count);
-      if (1 == bum->udp4_sessions_count)
+      if (multihop)
 	{
-	  udp_register_dst_port (vm, UDP_DST_PORT_bfd4,
-				 bfd_udp4_input_node.index, 1);
-	  udp_register_dst_port (vm, UDP_DST_PORT_bfd_echo4,
-				 bfd_udp_echo4_input_node.index, 1);
+	  ++bum->udp4_mh_sessions_count;
+	  bfd_udp_update_stat_segment_entry (
+	    bum->udp4_mh_sessions_count_stat_seg_entry,
+	    bum->udp4_mh_sessions_count);
+	  if (1 == bum->udp4_mh_sessions_count)
+	    {
+	      udp_register_dst_port (vm, UDP_DST_PORT_bfd4_mh,
+				     bfd_udp4_input_node.index, 1);
+	    }
+	}
+      else
+	{
+	  bus->adj_index = adj_nbr_add_or_lock (
+	    FIB_PROTOCOL_IP4, VNET_LINK_IP4, peer, key->sw_if_index);
+	  BFD_DBG ("adj_nbr_add_or_lock(FIB_PROTOCOL_IP4, VNET_LINK_IP4, "
+		   " %U, %d) returns %d",
+		   format_ip46_address, peer, IP46_TYPE_ANY, key->sw_if_index,
+		   bus->adj_index);
+	  ++bum->udp4_sh_sessions_count;
+	  bfd_udp_update_stat_segment_entry (
+	    bum->udp4_sh_sessions_count_stat_seg_entry,
+	    bum->udp4_sh_sessions_count);
+	  if (1 == bum->udp4_sh_sessions_count)
+	    {
+	      udp_register_dst_port (vm, UDP_DST_PORT_bfd4,
+				     bfd_udp4_input_node.index, 1);
+	      udp_register_dst_port (vm, UDP_DST_PORT_bfd_echo4,
+				     bfd_udp_echo4_input_node.index, 1);
+	    }
 	}
     }
   else
     {
-      bus->adj_index = adj_nbr_add_or_lock (FIB_PROTOCOL_IP6, VNET_LINK_IP6,
-					    peer, key->sw_if_index);
-      BFD_DBG ("adj_nbr_add_or_lock(FIB_PROTOCOL_IP6, VNET_LINK_IP6, %U, %d) "
-	       "returns %d",
-	       format_ip46_address, peer, IP46_TYPE_ANY, key->sw_if_index,
-	       bus->adj_index);
-      ++bum->udp6_sessions_count;
-      bfd_udp_update_stat_segment_entry (
-	bum->udp6_sessions_count_stat_seg_entry, bum->udp6_sessions_count);
-      if (1 == bum->udp6_sessions_count)
+      if (multihop)
 	{
-	  udp_register_dst_port (vm, UDP_DST_PORT_bfd6,
-				 bfd_udp6_input_node.index, 0);
-	  udp_register_dst_port (vm, UDP_DST_PORT_bfd_echo6,
-				 bfd_udp_echo6_input_node.index, 0);
+	  ++bum->udp6_mh_sessions_count;
+	  bfd_udp_update_stat_segment_entry (
+	    bum->udp6_mh_sessions_count_stat_seg_entry,
+	    bum->udp6_mh_sessions_count);
+	  if (1 == bum->udp6_mh_sessions_count)
+	    {
+	      udp_register_dst_port (vm, UDP_DST_PORT_bfd6_mh,
+				     bfd_udp6_input_node.index, 0);
+	    }
 	}
+      else
+	{
+	  bus->adj_index = adj_nbr_add_or_lock (
+	    FIB_PROTOCOL_IP6, VNET_LINK_IP6, peer, key->sw_if_index);
+	  BFD_DBG ("adj_nbr_add_or_lock(FIB_PROTOCOL_IP6, VNET_LINK_IP6, "
+		   "%U, %d) returns %d",
+		   format_ip46_address, peer, IP46_TYPE_ANY, key->sw_if_index,
+		   bus->adj_index);
+	  ++bum->udp6_sh_sessions_count;
+	  bfd_udp_update_stat_segment_entry (
+	    bum->udp6_sh_sessions_count_stat_seg_entry,
+	    bum->udp6_sh_sessions_count);
+	  if (1 == bum->udp6_sh_sessions_count)
+	    {
+	      udp_register_dst_port (vm, UDP_DST_PORT_bfd6,
+				     bfd_udp6_input_node.index, 0);
+	      udp_register_dst_port (vm, UDP_DST_PORT_bfd_echo6,
+				     bfd_udp_echo6_input_node.index, 0);
+	    }
+	}
+    }
+
+  if (multihop)
+    {
+      bs->hop_type = BFD_HOP_TYPE_MULTI;
+    }
+  else
+    {
+      bs->hop_type = BFD_HOP_TYPE_SINGLE;
     }
   *bs_out = bs;
   return bfd_session_set_params (bum->bfd_main, bs, desired_min_tx_usec,
@@ -590,20 +675,24 @@ bfd_udp_add_session_internal (vlib_main_t * vm, bfd_udp_main_t * bum,
 }
 
 static vnet_api_error_t
-bfd_udp_validate_api_input (u32 sw_if_index,
-			    const ip46_address_t * local_addr,
-			    const ip46_address_t * peer_addr)
+bfd_udp_validate_api_input (bool multihop, u32 sw_if_index,
+			    const ip46_address_t *local_addr,
+			    const ip46_address_t *peer_addr)
 {
   bfd_udp_main_t *bum = &bfd_udp_main;
-  vnet_sw_interface_t *sw_if =
-    vnet_get_sw_interface_or_null (bfd_udp_main.vnet_main, sw_if_index);
-  if (!sw_if)
+  if (!multihop)
     {
-      vlib_log_err (bum->log_class,
-		    "got NULL sw_if when getting interface by index %u",
-		    sw_if_index);
-      return VNET_API_ERROR_INVALID_SW_IF_INDEX;
+      vnet_sw_interface_t *sw_if =
+	vnet_get_sw_interface_or_null (bfd_udp_main.vnet_main, sw_if_index);
+      if (!sw_if)
+	{
+	  vlib_log_err (bum->log_class,
+			"got NULL sw_if when getting interface by index %u",
+			sw_if_index);
+	  return VNET_API_ERROR_INVALID_SW_IF_INDEX;
+	}
     }
+
   if (ip46_address_is_ip4 (local_addr))
     {
       if (!ip46_address_is_ip4 (peer_addr))
@@ -627,13 +716,13 @@ bfd_udp_validate_api_input (u32 sw_if_index,
 }
 
 static vnet_api_error_t
-bfd_udp_find_session_by_api_input (u32 sw_if_index,
-				   const ip46_address_t * local_addr,
-				   const ip46_address_t * peer_addr,
-				   bfd_session_t ** bs_out)
+bfd_udp_find_session_by_api_input (bool multihop, u32 sw_if_index,
+				   const ip46_address_t *local_addr,
+				   const ip46_address_t *peer_addr,
+				   bfd_session_t **bs_out)
 {
   vnet_api_error_t rv =
-    bfd_udp_validate_api_input (sw_if_index, local_addr, peer_addr);
+    bfd_udp_validate_api_input (multihop, sw_if_index, local_addr, peer_addr);
   if (!rv)
     {
       bfd_udp_main_t *bum = &bfd_udp_main;
@@ -647,8 +736,9 @@ bfd_udp_find_session_by_api_input (u32 sw_if_index,
       else
 	{
 	  vlib_log_err (bum->log_class,
-			"BFD session not found, sw_if_index=%u, local=%U, peer=%U",
-			sw_if_index, format_ip46_address, local_addr,
+			"BFD session not found, multihop=%d, sw_if_index=%u, "
+			"local=%U, peer=%U",
+			multihop, sw_if_index, format_ip46_address, local_addr,
 			IP46_TYPE_ANY, format_ip46_address, peer_addr,
 			IP46_TYPE_ANY);
 	  return VNET_API_ERROR_BFD_ENOENT;
@@ -658,13 +748,13 @@ bfd_udp_find_session_by_api_input (u32 sw_if_index,
 }
 
 static vnet_api_error_t
-bfd_api_verify_common (u32 sw_if_index, u32 desired_min_tx_usec,
+bfd_api_verify_common (bool multihop, u32 sw_if_index, u32 desired_min_tx_usec,
 		       u8 detect_mult, const ip46_address_t *local_addr,
 		       const ip46_address_t *peer_addr)
 {
   bfd_udp_main_t *bum = &bfd_udp_main;
   vnet_api_error_t rv =
-    bfd_udp_validate_api_input (sw_if_index, local_addr, peer_addr);
+    bfd_udp_validate_api_input (multihop, sw_if_index, local_addr, peer_addr);
   if (rv)
     {
       return rv;
@@ -693,31 +783,62 @@ bfd_udp_del_session_internal (vlib_main_t * vm, bfd_session_t * bs)
   switch (bs->transport)
     {
     case BFD_TRANSPORT_UDP4:
-      --bum->udp4_sessions_count;
-      bfd_udp_update_stat_segment_entry (
-	bum->udp4_sessions_count_stat_seg_entry, bum->udp4_sessions_count);
-      if (!bum->udp4_sessions_count)
+      if (bs->hop_type == BFD_HOP_TYPE_MULTI)
 	{
-	  udp_unregister_dst_port (vm, UDP_DST_PORT_bfd4, 1);
-	  udp_unregister_dst_port (vm, UDP_DST_PORT_bfd_echo4, 1);
+	  --bum->udp4_mh_sessions_count;
+	  bfd_udp_update_stat_segment_entry (
+	    bum->udp4_mh_sessions_count_stat_seg_entry,
+	    bum->udp4_mh_sessions_count);
+	  if (!bum->udp4_mh_sessions_count)
+	    {
+	      udp_unregister_dst_port (vm, UDP_DST_PORT_bfd4_mh, 1);
+	    }
+	}
+      else
+	{
+	  --bum->udp4_sh_sessions_count;
+	  bfd_udp_update_stat_segment_entry (
+	    bum->udp4_sh_sessions_count_stat_seg_entry,
+	    bum->udp4_sh_sessions_count);
+	  if (!bum->udp4_sh_sessions_count)
+	    {
+	      udp_unregister_dst_port (vm, UDP_DST_PORT_bfd4, 1);
+	      udp_unregister_dst_port (vm, UDP_DST_PORT_bfd_echo4, 1);
+	    }
 	}
       break;
     case BFD_TRANSPORT_UDP6:
-      --bum->udp6_sessions_count;
-      bfd_udp_update_stat_segment_entry (
-	bum->udp6_sessions_count_stat_seg_entry, bum->udp6_sessions_count);
-      if (!bum->udp6_sessions_count)
+      if (bs->hop_type == BFD_HOP_TYPE_MULTI)
+	{
+	  --bum->udp6_mh_sessions_count;
+	  bfd_udp_update_stat_segment_entry (
+	    bum->udp6_mh_sessions_count_stat_seg_entry,
+	    bum->udp6_mh_sessions_count);
+	  if (!bum->udp6_mh_sessions_count)
+	    {
+	      udp_unregister_dst_port (vm, UDP_DST_PORT_bfd6_mh, 0);
+	    }
+	}
+      else
 	{
-	  udp_unregister_dst_port (vm, UDP_DST_PORT_bfd6, 0);
-	  udp_unregister_dst_port (vm, UDP_DST_PORT_bfd_echo6, 0);
+	  --bum->udp6_sh_sessions_count;
+	  bfd_udp_update_stat_segment_entry (
+	    bum->udp6_sh_sessions_count_stat_seg_entry,
+	    bum->udp6_sh_sessions_count);
+	  if (!bum->udp6_sh_sessions_count)
+	    {
+	      udp_unregister_dst_port (vm, UDP_DST_PORT_bfd6, 0);
+	      udp_unregister_dst_port (vm, UDP_DST_PORT_bfd_echo6, 0);
+	    }
 	}
+
       break;
     }
   bfd_put_session (bum->bfd_main, bs);
 }
 
 static vnet_api_error_t
-bfd_udp_add_and_start_session (u32 sw_if_index,
+bfd_udp_add_and_start_session (bool multihop, u32 sw_if_index,
 			       const ip46_address_t *local_addr,
 			       const ip46_address_t *peer_addr,
 			       u32 desired_min_tx_usec,
@@ -728,9 +849,10 @@ bfd_udp_add_and_start_session (u32 sw_if_index,
   bfd_session_t *bs = NULL;
   vnet_api_error_t rv;
 
-  rv = bfd_udp_add_session_internal (
-    vlib_get_main (), &bfd_udp_main, sw_if_index, desired_min_tx_usec,
-    required_min_rx_usec, detect_mult, local_addr, peer_addr, &bs);
+  rv = bfd_udp_add_session_internal (vlib_get_main (), &bfd_udp_main, multihop,
+				     sw_if_index, desired_min_tx_usec,
+				     required_min_rx_usec, detect_mult,
+				     local_addr, peer_addr, &bs);
 
   if (!rv && is_authenticated)
     {
@@ -750,21 +872,22 @@ bfd_udp_add_and_start_session (u32 sw_if_index,
 }
 
 vnet_api_error_t
-bfd_udp_add_session (u32 sw_if_index, const ip46_address_t * local_addr,
-		     const ip46_address_t * peer_addr,
-		     u32 desired_min_tx_usec, u32 required_min_rx_usec,
-		     u8 detect_mult, u8 is_authenticated, u32 conf_key_id,
-		     u8 bfd_key_id)
+bfd_udp_add_session (bool multihop, u32 sw_if_index,
+		     const ip46_address_t *local_addr,
+		     const ip46_address_t *peer_addr, u32 desired_min_tx_usec,
+		     u32 required_min_rx_usec, u8 detect_mult,
+		     u8 is_authenticated, u32 conf_key_id, u8 bfd_key_id)
 {
   bfd_main_t *bm = &bfd_main;
   bfd_lock (bm);
 
-  vnet_api_error_t rv = bfd_api_verify_common (
-    sw_if_index, desired_min_tx_usec, detect_mult, local_addr, peer_addr);
+  vnet_api_error_t rv =
+    bfd_api_verify_common (multihop, sw_if_index, desired_min_tx_usec,
+			   detect_mult, local_addr, peer_addr);
 
   if (!rv)
     rv = bfd_udp_add_and_start_session (
-      sw_if_index, local_addr, peer_addr, desired_min_tx_usec,
+      multihop, sw_if_index, local_addr, peer_addr, desired_min_tx_usec,
       required_min_rx_usec, detect_mult, is_authenticated, conf_key_id,
       bfd_key_id);
 
@@ -773,7 +896,8 @@ bfd_udp_add_session (u32 sw_if_index, const ip46_address_t * local_addr,
 }
 
 vnet_api_error_t
-bfd_udp_upd_session (u32 sw_if_index, const ip46_address_t *local_addr,
+bfd_udp_upd_session (bool multihop, u32 sw_if_index,
+		     const ip46_address_t *local_addr,
 		     const ip46_address_t *peer_addr, u32 desired_min_tx_usec,
 		     u32 required_min_rx_usec, u8 detect_mult,
 		     u8 is_authenticated, u32 conf_key_id, u8 bfd_key_id)
@@ -781,17 +905,18 @@ bfd_udp_upd_session (u32 sw_if_index, const ip46_address_t *local_addr,
   bfd_main_t *bm = &bfd_main;
   bfd_lock (bm);
 
-  vnet_api_error_t rv = bfd_api_verify_common (
-    sw_if_index, desired_min_tx_usec, detect_mult, local_addr, peer_addr);
+  vnet_api_error_t rv =
+    bfd_api_verify_common (multihop, sw_if_index, desired_min_tx_usec,
+			   detect_mult, local_addr, peer_addr);
   if (!rv)
     {
       bfd_session_t *bs = NULL;
 
-      rv = bfd_udp_find_session_by_api_input (sw_if_index, local_addr,
-					      peer_addr, &bs);
+      rv = bfd_udp_find_session_by_api_input (multihop, sw_if_index,
+					      local_addr, peer_addr, &bs);
       if (VNET_API_ERROR_BFD_ENOENT == rv)
 	rv = bfd_udp_add_and_start_session (
-	  sw_if_index, local_addr, peer_addr, desired_min_tx_usec,
+	  multihop, sw_if_index, local_addr, peer_addr, desired_min_tx_usec,
 	  required_min_rx_usec, detect_mult, is_authenticated, conf_key_id,
 	  bfd_key_id);
       else
@@ -805,7 +930,8 @@ bfd_udp_upd_session (u32 sw_if_index, const ip46_address_t *local_addr,
 }
 
 vnet_api_error_t
-bfd_udp_mod_session (u32 sw_if_index, const ip46_address_t *local_addr,
+bfd_udp_mod_session (bool multihop, u32 sw_if_index,
+		     const ip46_address_t *local_addr,
 		     const ip46_address_t *peer_addr, u32 desired_min_tx_usec,
 		     u32 required_min_rx_usec, u8 detect_mult)
 {
@@ -813,9 +939,8 @@ bfd_udp_mod_session (u32 sw_if_index, const ip46_address_t *local_addr,
   bfd_main_t *bm = &bfd_main;
   vnet_api_error_t error;
   bfd_lock (bm);
-  vnet_api_error_t rv =
-    bfd_udp_find_session_by_api_input (sw_if_index, local_addr, peer_addr,
-				       &bs);
+  vnet_api_error_t rv = bfd_udp_find_session_by_api_input (
+    multihop, sw_if_index, local_addr, peer_addr, &bs);
   if (rv)
     {
       bfd_unlock (bm);
@@ -830,16 +955,15 @@ bfd_udp_mod_session (u32 sw_if_index, const ip46_address_t *local_addr,
 }
 
 vnet_api_error_t
-bfd_udp_del_session (u32 sw_if_index,
-		     const ip46_address_t * local_addr,
-		     const ip46_address_t * peer_addr)
+bfd_udp_del_session (bool multihop, u32 sw_if_index,
+		     const ip46_address_t *local_addr,
+		     const ip46_address_t *peer_addr)
 {
   bfd_session_t *bs = NULL;
   bfd_main_t *bm = &bfd_main;
   bfd_lock (bm);
-  vnet_api_error_t rv =
-    bfd_udp_find_session_by_api_input (sw_if_index, local_addr, peer_addr,
-				       &bs);
+  vnet_api_error_t rv = bfd_udp_find_session_by_api_input (
+    multihop, sw_if_index, local_addr, peer_addr, &bs);
   if (rv)
     {
       bfd_unlock (bm);
@@ -851,16 +975,15 @@ bfd_udp_del_session (u32 sw_if_index,
 }
 
 vnet_api_error_t
-bfd_udp_session_set_flags (vlib_main_t * vm, u32 sw_if_index,
-			   const ip46_address_t * local_addr,
-			   const ip46_address_t * peer_addr, u8 admin_up_down)
+bfd_udp_session_set_flags (vlib_main_t *vm, bool multihop, u32 sw_if_index,
+			   const ip46_address_t *local_addr,
+			   const ip46_address_t *peer_addr, u8 admin_up_down)
 {
   bfd_session_t *bs = NULL;
   bfd_main_t *bm = &bfd_main;
   bfd_lock (bm);
-  vnet_api_error_t rv =
-    bfd_udp_find_session_by_api_input (sw_if_index, local_addr, peer_addr,
-				       &bs);
+  vnet_api_error_t rv = bfd_udp_find_session_by_api_input (
+    multihop, sw_if_index, local_addr, peer_addr, &bs);
   if (rv)
     {
       bfd_unlock (bm);
@@ -872,19 +995,18 @@ bfd_udp_session_set_flags (vlib_main_t * vm, u32 sw_if_index,
 }
 
 vnet_api_error_t
-bfd_udp_auth_activate (u32 sw_if_index,
-		       const ip46_address_t * local_addr,
-		       const ip46_address_t * peer_addr,
-		       u32 conf_key_id, u8 key_id, u8 is_delayed)
+bfd_udp_auth_activate (bool multihop, u32 sw_if_index,
+		       const ip46_address_t *local_addr,
+		       const ip46_address_t *peer_addr, u32 conf_key_id,
+		       u8 key_id, u8 is_delayed)
 {
   bfd_main_t *bm = &bfd_main;
   bfd_lock (bm);
   vnet_api_error_t error;
 
   bfd_session_t *bs = NULL;
-  vnet_api_error_t rv =
-    bfd_udp_find_session_by_api_input (sw_if_index, local_addr, peer_addr,
-				       &bs);
+  vnet_api_error_t rv = bfd_udp_find_session_by_api_input (
+    multihop, sw_if_index, local_addr, peer_addr, &bs);
   if (rv)
     {
       bfd_unlock (bm);
@@ -896,17 +1018,16 @@ bfd_udp_auth_activate (u32 sw_if_index,
 }
 
 vnet_api_error_t
-bfd_udp_auth_deactivate (u32 sw_if_index,
-			 const ip46_address_t * local_addr,
-			 const ip46_address_t * peer_addr, u8 is_delayed)
+bfd_udp_auth_deactivate (bool multihop, u32 sw_if_index,
+			 const ip46_address_t *local_addr,
+			 const ip46_address_t *peer_addr, u8 is_delayed)
 {
   bfd_main_t *bm = &bfd_main;
   vnet_api_error_t error;
   bfd_lock (bm);
   bfd_session_t *bs = NULL;
-  vnet_api_error_t rv =
-    bfd_udp_find_session_by_api_input (sw_if_index, local_addr, peer_addr,
-				       &bs);
+  vnet_api_error_t rv = bfd_udp_find_session_by_api_input (
+    multihop, sw_if_index, local_addr, peer_addr, &bs);
   if (rv)
     {
       bfd_unlock (bm);
@@ -985,13 +1106,19 @@ bfd_udp4_verify_transport (const ip4_header_t *ip4, const udp_header_t *udp,
 	       key->local_addr.ip4.as_u8);
       return BFD_UDP_ERROR_DST_MISMATCH;
     }
-  const u8 expected_ttl = 255;
-  if (ip4->ttl != expected_ttl)
+
+  // For single-hop, TTL must be 255
+  if (bs->hop_type == BFD_HOP_TYPE_SINGLE)
     {
-      BFD_ERR ("IPv4 unexpected TTL value %u, expected %u", ip4->ttl,
-	       expected_ttl);
-      return BFD_UDP_ERROR_TTL;
+      const u8 expected_ttl = 255;
+      if (ip4->ttl != expected_ttl)
+	{
+	  BFD_ERR ("IPv4 unexpected TTL value %u, expected %u", ip4->ttl,
+		   expected_ttl);
+	  return BFD_UDP_ERROR_TTL;
+	}
     }
+
   if (clib_net_to_host_u16 (udp->src_port) < 49152)
     {
       BFD_ERR ("Invalid UDP src port %u, out of range <49152,65535>",
@@ -1062,7 +1189,14 @@ bfd_udp4_scan (vlib_main_t *vm, vlib_buffer_t *b, bfd_session_t **bs_out)
     {
       bfd_udp_key_t key;
       clib_memset (&key, 0, sizeof (key));
-      key.sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
+      if (udp->dst_port == clib_host_to_net_u16 (UDP_DST_PORT_bfd4_mh))
+	{
+	  key.sw_if_index = ~0;
+	}
+      else
+	{
+	  key.sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
+	}
       key.local_addr.ip4.as_u32 = ip4->dst_address.as_u32;
       key.peer_addr.ip4.as_u32 = ip4->src_address.as_u32;
       BFD_DBG ("Looking up BFD session using key (sw_if_index=%u, local=%U, "
@@ -1145,13 +1279,19 @@ bfd_udp6_verify_transport (const ip6_header_t *ip6, const udp_header_t *udp,
 	       &key->local_addr.ip6);
       return BFD_UDP_ERROR_DST_MISMATCH;
     }
-  const u8 expected_hop_limit = 255;
-  if (ip6->hop_limit != expected_hop_limit)
+
+  // For single-hop, hop-limit must be 255
+  if (bs->hop_type == BFD_HOP_TYPE_SINGLE)
     {
-      BFD_ERR ("IPv6 unexpected hop-limit value %u, expected %u",
-	       ip6->hop_limit, expected_hop_limit);
-      return BFD_UDP_ERROR_TTL;
+      const u8 expected_hop_limit = 255;
+      if (ip6->hop_limit != expected_hop_limit)
+	{
+	  BFD_ERR ("IPv6 unexpected hop-limit value %u, expected %u",
+		   ip6->hop_limit, expected_hop_limit);
+	  return BFD_UDP_ERROR_TTL;
+	}
     }
+
   if (clib_net_to_host_u16 (udp->src_port) < 49152)
     {
       BFD_ERR ("Invalid UDP src port %u, out of range <49152,65535>",
@@ -1204,15 +1344,22 @@ bfd_udp6_scan (vlib_main_t *vm, vlib_buffer_t *b, bfd_session_t **bs_out)
     {
       bfd_udp_key_t key;
       clib_memset (&key, 0, sizeof (key));
-      key.sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
+      if (udp->dst_port == clib_host_to_net_u16 (UDP_DST_PORT_bfd6_mh))
+	{
+	  key.sw_if_index = ~0;
+	}
+      else
+	{
+	  key.sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
+	}
       key.local_addr.ip6.as_u64[0] = ip6->dst_address.as_u64[0];
       key.local_addr.ip6.as_u64[1] = ip6->dst_address.as_u64[1];
       key.peer_addr.ip6.as_u64[0] = ip6->src_address.as_u64[0];
       key.peer_addr.ip6.as_u64[1] = ip6->src_address.as_u64[1];
-      BFD_DBG ("Looking up BFD session using key (sw_if_index=%u, local=%U, "
-	       "peer=%U)",
-	       key.sw_if_index, format_ip6_address, &key.local_addr,
-	       format_ip6_address, &key.peer_addr);
+      BFD_DBG ("Looking up BFD session using discriminator %u",
+	       pkt->your_disc);
+      bs = bfd_find_session_by_disc (bfd_udp_main.bfd_main, pkt->your_disc);
+
       bs = bfd_lookup_session (&bfd_udp_main, &key);
     }
   if (!bs)
@@ -1266,8 +1413,8 @@ bfd_udp_input (vlib_main_t * vm, vlib_node_runtime_t * rt,
 	{
 	  u64 len;
 	  t0 = vlib_add_trace (vm, rt, b0, sizeof (*t0));
-	  len = (b0->current_length < sizeof (t0->data)) ? b0->current_length
-	    : sizeof (t0->data);
+	  len = (b0->current_length < sizeof (t0->data)) ? b0->current_length :
+							   sizeof (t0->data);
 	  t0->len = len;
 	  clib_memcpy_fast (t0->data, vlib_buffer_get_current (b0), len);
 	}
@@ -1311,25 +1458,35 @@ bfd_udp_input (vlib_main_t * vm, vlib_node_runtime_t * rt,
 		  vlib_node_increment_counter (vm, bfd_udp4_input_node.index,
 					       error0, 1);
 		}
+
 	      const bfd_udp_session_t *bus = &bs->udp;
-	      ip_adjacency_t *adj = adj_get (bus->adj_index);
-	      switch (adj->lookup_next_index)
+
+	      if (bs->hop_type == BFD_HOP_TYPE_MULTI)
 		{
-		case IP_LOOKUP_NEXT_ARP:
-		  next0 = BFD_UDP_INPUT_NEXT_REPLY_ARP;
-		  break;
-		case IP_LOOKUP_NEXT_REWRITE:
 		  next0 = BFD_UDP_INPUT_NEXT_REPLY_REWRITE;
-		  break;
-		case IP_LOOKUP_NEXT_MIDCHAIN:
-		  next0 = BFD_UDP_INPUT_NEXT_REPLY_MIDCHAIN;
-		  break;
-		default:
-		  /* drop */
-		  break;
+		}
+	      else
+		{
+		  ip_adjacency_t *adj = adj_get (bus->adj_index);
+		  switch (adj->lookup_next_index)
+		    {
+		    case IP_LOOKUP_NEXT_ARP:
+		      next0 = BFD_UDP_INPUT_NEXT_REPLY_ARP;
+		      break;
+		    case IP_LOOKUP_NEXT_REWRITE:
+		      next0 = BFD_UDP_INPUT_NEXT_REPLY_REWRITE;
+		      break;
+		    case IP_LOOKUP_NEXT_MIDCHAIN:
+		      next0 = BFD_UDP_INPUT_NEXT_REPLY_MIDCHAIN;
+		      break;
+		    default:
+		      /* drop */
+		      break;
+		    }
 		}
 	    }
 	}
+
       bfd_unlock (bm);
       vlib_set_next_frame_buffer (vm, rt, next0, bi0);
 
@@ -1566,6 +1723,10 @@ bfd_udp_sw_if_add_del (CLIB_UNUSED (vnet_main_t *vnm), u32 sw_if_index,
 	    {
 	      continue;
 	    }
+	  if (bs->hop_type == BFD_HOP_TYPE_MULTI)
+	    {
+	      continue;
+	    }
 	  if (bs->udp.key.sw_if_index != sw_if_index)
 	    {
 	      continue;
@@ -1593,24 +1754,47 @@ clib_error_t *
 bfd_udp_stats_init (bfd_udp_main_t *bum)
 {
   const char *name4 = "/bfd/udp4/sessions";
-  bum->udp4_sessions_count_stat_seg_entry = vlib_stats_add_gauge ("%s", name4);
+  bum->udp4_sh_sessions_count_stat_seg_entry =
+    vlib_stats_add_gauge ("%s", name4);
 
-  vlib_stats_set_gauge (bum->udp4_sessions_count_stat_seg_entry, 0);
-  if (~0 == bum->udp4_sessions_count_stat_seg_entry)
+  vlib_stats_set_gauge (bum->udp4_sh_sessions_count_stat_seg_entry, 0);
+  if (~0 == bum->udp4_sh_sessions_count_stat_seg_entry)
     {
       return clib_error_return (
 	0, "Could not create stat segment entry for %s", name4);
     }
   const char *name6 = "/bfd/udp6/sessions";
-  bum->udp6_sessions_count_stat_seg_entry = vlib_stats_add_gauge ("%s", name6);
+  bum->udp6_sh_sessions_count_stat_seg_entry =
+    vlib_stats_add_gauge ("%s", name6);
 
-  vlib_stats_set_gauge (bum->udp6_sessions_count_stat_seg_entry, 0);
-  if (~0 == bum->udp6_sessions_count_stat_seg_entry)
+  vlib_stats_set_gauge (bum->udp6_sh_sessions_count_stat_seg_entry, 0);
+  if (~0 == bum->udp6_sh_sessions_count_stat_seg_entry)
     {
       return clib_error_return (
 	0, "Could not create stat segment entry for %s", name6);
     }
 
+  const char *name4_mh = "/bfd/udp4/sessions_mh";
+  bum->udp4_mh_sessions_count_stat_seg_entry =
+    vlib_stats_add_gauge ("%s", name4_mh);
+
+  vlib_stats_set_gauge (bum->udp4_mh_sessions_count_stat_seg_entry, 0);
+  if (~0 == bum->udp4_mh_sessions_count_stat_seg_entry)
+    {
+      return clib_error_return (
+	0, "Could not create stat segment entry for %s", name4_mh);
+    }
+  const char *name6_mh = "/bfd/udp6/sessions_mh";
+  bum->udp6_mh_sessions_count_stat_seg_entry =
+    vlib_stats_add_gauge ("%s", name6_mh);
+
+  vlib_stats_set_gauge (bum->udp6_mh_sessions_count_stat_seg_entry, 0);
+  if (~0 == bum->udp6_mh_sessions_count_stat_seg_entry)
+    {
+      return clib_error_return (
+	0, "Could not create stat segment entry for %s", name6_mh);
+    }
+
   return 0;
 }
 
@@ -1620,8 +1804,10 @@ bfd_udp_stats_init (bfd_udp_main_t *bum)
 static clib_error_t *
 bfd_udp_init (vlib_main_t * vm)
 {
-  bfd_udp_main.udp4_sessions_count = 0;
-  bfd_udp_main.udp6_sessions_count = 0;
+  bfd_udp_main.udp4_sh_sessions_count = 0;
+  bfd_udp_main.udp6_sh_sessions_count = 0;
+  bfd_udp_main.udp4_mh_sessions_count = 0;
+  bfd_udp_main.udp6_mh_sessions_count = 0;
   mhash_init (&bfd_udp_main.bfd_session_idx_by_bfd_key, sizeof (uword),
 	      sizeof (bfd_udp_key_t));
   bfd_udp_main.bfd_main = &bfd_main;
diff --git a/src/vnet/bfd/bfd_udp.h b/src/vnet/bfd/bfd_udp.h
index 8f4bfee2bd7..362e9541dfe 100644
--- a/src/vnet/bfd/bfd_udp.h
+++ b/src/vnet/bfd/bfd_udp.h
@@ -26,12 +26,10 @@
 
 /** identifier of BFD session based on UDP transport only */
 typedef CLIB_PACKED (struct {
-  union {
-    /** interface to which the session is tied - single-hop */
-    u32 sw_if_index;
-    /** the FIB index the peer is in - multi-hop*/
-    u32 fib_index;
-  };
+  /** interface to which the session is tied - single-hop */
+  u16 sw_if_index;
+  /** the FIB index the peer is in - multi-hop*/
+  u16 fib_index;
   /** local address */
   ip46_address_t local_addr;
   /** peer address */