MPLS Unifom mode

- support both pipe and uniform modes for all MPLS LSP
- all API programming for output-labels requires that the mode (and associated data) is specificed
   - API changes in MPLS, BIER and IP are involved
- new DPO [sub] types for MPLS labels to handle the two modes.

Change-Id: I87b76401e996f10dfbdbe4552ff6b19af958783c
Signed-off-by: Neale Ranns <nranns@cisco.com>

13 files changed, 399 insertions, 95 deletions

diff --git a/src/vnet/fib/fib_api.h b/src/vnet/fib/fib_api.h
index bbe4eaac74b..d10ba00913b 100644
--- a/src/vnet/fib/fib_api.h
+++ b/src/vnet/fib/fib_api.h
@@ -53,7 +53,7 @@ add_del_route_t_handler (u8 is_multipath,
 			 u16 next_hop_weight,
 			 u16 next_hop_preference,
 			 mpls_label_t next_hop_via_label,
-			 mpls_label_t * next_hop_out_label_stack);
+			 fib_mpls_label_t * next_hop_out_label_stack);
 
 void
 copy_fib_next_hop (fib_route_path_encode_t * api_rpath,
diff --git a/src/vnet/fib/fib_entry_src.c b/src/vnet/fib/fib_entry_src.c
index 6dc0c73a305..ec8c7393030 100644
--- a/src/vnet/fib/fib_entry_src.c
+++ b/src/vnet/fib/fib_entry_src.c
@@ -212,6 +212,7 @@ static int
 fib_entry_src_valid_out_label (mpls_label_t label)
 {
     return ((MPLS_LABEL_IS_REAL(label) ||
+             MPLS_LABEL_POP == label ||
              MPLS_IETF_IPV4_EXPLICIT_NULL_LABEL == label ||
              MPLS_IETF_IPV6_EXPLICIT_NULL_LABEL == label ||
              MPLS_IETF_IMPLICIT_NULL_LABEL == label));
@@ -330,6 +331,7 @@ fib_entry_src_get_path_forwarding (fib_node_index_t path_index,
                                            &nh->path_dpo);
             fib_path_stack_mpls_disp(path_index,
                                      fib_prefix_get_payload_proto(&ctx->fib_entry->fe_prefix),
+                                     FIB_MPLS_LSP_MODE_PIPE,
                                      &nh->path_dpo);
 
             break;
@@ -391,7 +393,7 @@ fib_entry_src_collect_forwarding (fib_node_index_t pl_index,
         switch (path_ext->fpe_type)
         {
         case FIB_PATH_EXT_MPLS:
-            if (fib_entry_src_valid_out_label(path_ext->fpe_label_stack[0]))
+            if (fib_entry_src_valid_out_label(path_ext->fpe_label_stack[0].fml_value))
             {
                 /*
                  * found a matching extension. stack it to obtain the forwarding
diff --git a/src/vnet/fib/fib_path.c b/src/vnet/fib/fib_path.c
index b4f9971f52e..a8593905438 100644
--- a/src/vnet/fib/fib_path.c
+++ b/src/vnet/fib/fib_path.c
@@ -1349,7 +1349,8 @@ fib_path_create (fib_node_index_t pl_index,
 	    {
 		path->fp_type = FIB_PATH_TYPE_DEAG;
 		path->deag.fp_tbl_id = rpath->frp_fib_index;
-	    }		
+                path->deag.fp_rpf_id = ~0;
+	    }
 	}
 	else
 	{
@@ -2238,6 +2239,7 @@ fib_path_contribute_urpf (fib_node_index_t path_index,
 void
 fib_path_stack_mpls_disp (fib_node_index_t path_index,
                           dpo_proto_t payload_proto,
+                          fib_mpls_lsp_mode_t mode,
                           dpo_id_t *dpo)
 {
     fib_path_t *path;
@@ -2253,10 +2255,8 @@ fib_path_stack_mpls_disp (fib_node_index_t path_index,
         dpo_id_t tmp = DPO_INVALID;
 
         dpo_copy(&tmp, dpo);
-        dpo_set(dpo,
-                DPO_MPLS_DISPOSITION,
-                payload_proto,
-                mpls_disp_dpo_create(payload_proto, ~0, &tmp));
+
+        mpls_disp_dpo_create(payload_proto, ~0, mode, &tmp, dpo);
         dpo_reset(&tmp);
         break;
     }                
@@ -2265,12 +2265,10 @@ fib_path_stack_mpls_disp (fib_node_index_t path_index,
         dpo_id_t tmp = DPO_INVALID;
 
         dpo_copy(&tmp, dpo);
-        dpo_set(dpo,
-                DPO_MPLS_DISPOSITION,
-                payload_proto,
-                mpls_disp_dpo_create(payload_proto,
-                                     path->deag.fp_rpf_id,
-                                     &tmp));
+
+        mpls_disp_dpo_create(payload_proto,
+                             path->deag.fp_rpf_id,
+                             mode, &tmp, dpo);
         dpo_reset(&tmp);
         break;
     }
diff --git a/src/vnet/fib/fib_path.h b/src/vnet/fib/fib_path.h
index 70b2f503aa8..28ec10a98d5 100644
--- a/src/vnet/fib/fib_path.h
+++ b/src/vnet/fib/fib_path.h
@@ -159,6 +159,7 @@ extern load_balance_path_t * fib_path_append_nh_for_multipath_hash(
     load_balance_path_t *hash_key);
 extern void fib_path_stack_mpls_disp(fib_node_index_t path_index,
                                      dpo_proto_t payload_proto,
+                                     fib_mpls_lsp_mode_t mode,
                                      dpo_id_t *dpo);
 extern void fib_path_contribute_forwarding(fib_node_index_t path_index,
 					   fib_forward_chain_type_t type,
diff --git a/src/vnet/fib/fib_path_ext.c b/src/vnet/fib/fib_path_ext.c
index a285ba07f7c..6b5b841c2ac 100644
--- a/src/vnet/fib/fib_path_ext.c
+++ b/src/vnet/fib/fib_path_ext.c
@@ -25,6 +25,7 @@
 #include <vnet/fib/fib_internal.h>
 
 const char *fib_path_ext_adj_flags_names[] = FIB_PATH_EXT_ADJ_ATTR_NAMES;
+const char *fib_path_ext_mpls_flags_names[] = FIB_PATH_EXT_MPLS_ATTR_NAMES;
 
 u8 *
 format_fib_path_ext (u8 * s, va_list * args)
@@ -38,30 +39,46 @@ format_fib_path_ext (u8 * s, va_list * args)
 
     switch (path_ext->fpe_type)
     {
-    case FIB_PATH_EXT_MPLS:
-        s = format(s, "labels:",
+    case FIB_PATH_EXT_MPLS: {
+        fib_path_ext_mpls_attr_t attr;
+
+        if (path_ext->fpe_mpls_flags)
+        {
+            s = format(s, "mpls-flags:[");
+
+            FOR_EACH_PATH_EXT_MPLS_ATTR(attr)
+            {
+                if ((1<<attr) & path_ext->fpe_mpls_flags) {
+                    s = format(s, "%s", fib_path_ext_mpls_flags_names[attr]);
+                }
+            }
+            s = format(s, "]");
+        }
+        s = format(s, " labels:[",
                    path_ext->fpe_path_index);
         for (ii = 0; ii < vec_len(path_ext->fpe_path.frp_label_stack); ii++)
         {
-            s = format(s, "%U ",
-                       format_mpls_unicast_label,
-                       path_ext->fpe_path.frp_label_stack[ii]);
+            s = format(s, "[%U]",
+                       format_fib_mpls_label,
+                       &path_ext->fpe_path.frp_label_stack[ii]);
         }
+        s = format(s, "]");
         break;
+    }
     case FIB_PATH_EXT_ADJ: {
         fib_path_ext_adj_attr_t attr;
 
-        s = format(s, "adj-flags:");
         if (path_ext->fpe_adj_flags)
         {
+            s = format(s, "adj-flags:[");
             FOR_EACH_PATH_EXT_ADJ_ATTR(attr)
             {
-                s = format(s, "%s", fib_path_ext_adj_flags_names[attr]);
+                if ((1<<attr) & path_ext->fpe_adj_flags)
+                {
+                    s = format(s, "%s", fib_path_ext_adj_flags_names[attr]);
+                }
             }
-        }
-        else
-        {
-            s = format(s, "None");
+            s = format(s, "]");
         }
         break;
     }
@@ -121,12 +138,28 @@ fib_path_ext_init (fib_path_ext_t *path_ext,
 
 /**
  * @brief Return true if the label stack is implicit null
+ * imp-null and pop equate to the same this as this level -
+ * the label is coming off.
  */
 static int
 fib_path_ext_is_imp_null (fib_path_ext_t *path_ext)
 {
     return ((1 == vec_len(path_ext->fpe_label_stack)) &&
-	    (MPLS_IETF_IMPLICIT_NULL_LABEL == path_ext->fpe_label_stack[0]));
+	    ((MPLS_IETF_IMPLICIT_NULL_LABEL == path_ext->fpe_label_stack[0].fml_value) ||
+             (MPLS_LABEL_POP == path_ext->fpe_label_stack[0].fml_value)));
+}
+
+mpls_label_dpo_flags_t
+fib_path_ext_mpls_flags_to_mpls_label (fib_path_ext_mpls_flags_t fpe_flags)
+{
+    mpls_label_dpo_flags_t ml_flags = MPLS_LABEL_DPO_FLAG_NONE;
+
+    if (fpe_flags &FIB_PATH_EXT_MPLS_FLAG_NO_IP_TTL_DECR)
+    {
+        ml_flags |= MPLS_LABEL_DPO_FLAG_NO_IP_TTL_DECR;
+    }
+
+    return (ml_flags);
 }
 
 load_balance_path_t *
@@ -236,24 +269,25 @@ fib_path_ext_stack (fib_path_ext_t *path_ext,
              * we pickup the correct MPLS imposition nodes to do
              * ip[46] processing.
              */
+            dpo_id_t parent = DPO_INVALID;
             dpo_proto_t chain_proto;
             mpls_eos_bit_t eos;
-            index_t mldi;
 
             eos = (child_fct == FIB_FORW_CHAIN_TYPE_MPLS_NON_EOS ?
                    MPLS_NON_EOS :
                    MPLS_EOS);
             chain_proto = fib_forw_chain_type_to_dpo_proto(child_fct);
 
-            mldi = mpls_label_dpo_create(path_ext->fpe_label_stack,
-                                         eos, 255, 0,
-                                         chain_proto,
-                                         &nh->path_dpo);
+            dpo_copy(&parent, &nh->path_dpo);
+            mpls_label_dpo_create(path_ext->fpe_label_stack,
+                                  eos,
+                                  chain_proto,
+                                  fib_path_ext_mpls_flags_to_mpls_label(
+                                      path_ext->fpe_mpls_flags),
+                                  &parent,
+                                  &nh->path_dpo);
 
-	    dpo_set(&nh->path_dpo,
-		    DPO_MPLS_LABEL,
-                    chain_proto,
-                    mldi);
+	    dpo_reset(&parent);
 	}
         else if (child_fct == FIB_FORW_CHAIN_TYPE_MPLS_EOS)
         {
@@ -262,6 +296,7 @@ fib_path_ext_stack (fib_path_ext_t *path_ext,
              */
             fib_path_stack_mpls_disp(nh->path_index,
                                      fib_forw_chain_type_to_dpo_proto(parent_fct),
+                                     path_ext->fpe_label_stack[0].fml_mode,
                                      &nh->path_dpo);
         }
     }
diff --git a/src/vnet/fib/fib_path_ext.h b/src/vnet/fib/fib_path_ext.h
index d07941c108b..b49fd977a20 100644
--- a/src/vnet/fib/fib_path_ext.h
+++ b/src/vnet/fib/fib_path_ext.h
@@ -60,6 +60,32 @@ typedef enum fib_path_ext_adj_flags_t_
          _item++)
 
 /**
+ * Flags present on an MPLS label sourced path-extension
+ */
+typedef enum fib_path_ext_mpls_attr_t_
+{
+    /**
+     * Do not decrement the TTL of IP packet during imposition
+     */
+    FIB_PATH_EXT_MPLS_ATTR_NO_IP_TTL_DECR,
+} fib_path_ext_mpls_attr_t;
+
+typedef enum fib_path_ext_mpls_flags_t_
+{
+    FIB_PATH_EXT_MPLS_FLAG_NONE = 0,
+    FIB_PATH_EXT_MPLS_FLAG_NO_IP_TTL_DECR = (1 << FIB_PATH_EXT_MPLS_ATTR_NO_IP_TTL_DECR),
+} fib_path_ext_mpls_flags_t;
+
+#define FIB_PATH_EXT_MPLS_ATTR_NAMES {                               \
+    [FIB_PATH_EXT_MPLS_ATTR_NO_IP_TTL_DECR] = "no-ip-tll-decr",      \
+}
+
+#define FOR_EACH_PATH_EXT_MPLS_ATTR(_item)                \
+    for (_item = FIB_PATH_EXT_MPLS_ATTR_NO_IP_TTL_DECR;   \
+         _item <= FIB_PATH_EXT_MPLS_ATTR_NO_IP_TTL_DECR;  \
+         _item++)
+
+/**
  * A path extension is a per-entry addition to the forwarding information
  * when packets are sent for that entry over that path.
  *
@@ -86,6 +112,12 @@ typedef struct fib_path_ext_t_
          * Flags describing the adj state
          */
         fib_path_ext_adj_flags_t fpe_adj_flags;
+        /**
+         * For an MPLS type extension
+         *
+         * Flags describing the mpls state
+         */
+        fib_path_ext_mpls_flags_t fpe_mpls_flags;
     };
 
     /**
@@ -98,7 +130,7 @@ typedef struct fib_path_ext_t_
      * position in the path-list.
      */
     fib_node_index_t fpe_path_index;
-} __attribute__ ((packed))  fib_path_ext_t;
+} __attribute__ ((packed)) fib_path_ext_t;
 
 extern u8 * format_fib_path_ext(u8 * s, va_list * args);
 
diff --git a/src/vnet/fib/fib_table.c b/src/vnet/fib/fib_table.c
index e9173484dec..324a35fe1e8 100644
--- a/src/vnet/fib/fib_table.c
+++ b/src/vnet/fib/fib_table.c
@@ -520,7 +520,7 @@ fib_table_entry_path_add (u32 fib_index,
 			  u32 next_hop_sw_if_index,
 			  u32 next_hop_fib_index,
 			  u32 next_hop_weight,
-			  mpls_label_t *next_hop_labels,
+			  fib_mpls_label_t *next_hop_labels,
 			  fib_route_path_flags_t path_flags)
 {
     fib_route_path_t path = {
@@ -770,7 +770,7 @@ fib_table_entry_update_one_path (u32 fib_index,
 				 u32 next_hop_sw_if_index,
 				 u32 next_hop_fib_index,
 				 u32 next_hop_weight,
-				 mpls_label_t *next_hop_labels,
+				 fib_mpls_label_t *next_hop_labels,
 				 fib_route_path_flags_t path_flags)
 {
     fib_node_index_t fib_entry_index;
diff --git a/src/vnet/fib/fib_table.h b/src/vnet/fib/fib_table.h
index ddc00e537c2..ffad3c43d3e 100644
--- a/src/vnet/fib/fib_table.h
+++ b/src/vnet/fib/fib_table.h
@@ -338,7 +338,7 @@ extern fib_node_index_t fib_table_entry_path_add(u32 fib_index,
 						 u32 next_hop_sw_if_index,
 						 u32 next_hop_fib_index,
 						 u32 next_hop_weight,
-						 mpls_label_t *next_hop_label_stack,
+						 fib_mpls_label_t *next_hop_label_stack,
 						 fib_route_path_flags_t pf);
 /**
  * @brief
@@ -521,7 +521,7 @@ extern fib_node_index_t fib_table_entry_update_one_path(u32 fib_index,
 							u32 next_hop_sw_if_index,
 							u32 next_hop_fib_index,
 							u32 next_hop_weight,
-							mpls_label_t *next_hop_label_stack,
+							fib_mpls_label_t *next_hop_label_stack,
 							fib_route_path_flags_t pf);
 
 /**
diff --git a/src/vnet/fib/fib_test.c b/src/vnet/fib/fib_test.c
index 2a30b3cd4cf..8f7bba0369a 100644
--- a/src/vnet/fib/fib_test.c
+++ b/src/vnet/fib/fib_test.c
@@ -301,7 +301,8 @@ fib_test_validate_rep_v (const replicate_t *rep,
 	    {
 		const mpls_label_dpo_t *mld;
                 mpls_label_t hdr;
-		FIB_TEST_LB((DPO_MPLS_LABEL == dpo->dpoi_type),
+		FIB_TEST_LB((mpls_label_dpo_get_type(MPLS_LABEL_DPO_FLAG_NONE)
+                             == dpo->dpoi_type),
                             "bucket %d stacks on %U",
                             bucket,
                             format_dpo_type, dpo->dpoi_type);
@@ -375,14 +376,19 @@ fib_test_validate_lb_v (const load_balance_t *lb,
 	case FT_LB_LABEL_STACK_O_ADJ:
 	    {
 		const mpls_label_dpo_t *mld;
+                mpls_label_dpo_flags_t mf;
                 mpls_label_t hdr;
 		u32 ii;
 
-		FIB_TEST_LB((DPO_MPLS_LABEL == dpo->dpoi_type),
+                mf = ((exp->label_stack_o_adj.mode ==
+                       FIB_MPLS_LSP_MODE_UNIFORM) ?
+                      MPLS_LABEL_DPO_FLAG_UNIFORM_MODE :
+                      MPLS_LABEL_DPO_FLAG_NONE);
+		FIB_TEST_LB((mpls_label_dpo_get_type(mf) == dpo->dpoi_type),
 			   "bucket %d stacks on %U",
 			   bucket,
 			   format_dpo_type, dpo->dpoi_type);
-	    
+
 		mld = mpls_label_dpo_get(dpo->dpoi_index);
 
 		FIB_TEST_LB(exp->label_stack_o_adj.label_stack_size == mld->mld_n_labels,
@@ -433,7 +439,8 @@ fib_test_validate_lb_v (const load_balance_t *lb,
 	    {
 		const mpls_label_dpo_t *mld;
                 mpls_label_t hdr;
-		FIB_TEST_LB((DPO_MPLS_LABEL == dpo->dpoi_type),
+		FIB_TEST_LB((mpls_label_dpo_get_type(MPLS_LABEL_DPO_FLAG_NONE)
+                             == dpo->dpoi_type),
 			   "bucket %d stacks on %U",
 			   bucket,
 			   format_dpo_type, dpo->dpoi_type);
@@ -468,13 +475,18 @@ fib_test_validate_lb_v (const load_balance_t *lb,
 	case FT_LB_LABEL_O_LB:
 	    {
 		const mpls_label_dpo_t *mld;
+                mpls_label_dpo_flags_t mf;
                 mpls_label_t hdr;
 
-		FIB_TEST_LB((DPO_MPLS_LABEL == dpo->dpoi_type),
+                mf = ((exp->label_o_lb.mode ==
+                       FIB_MPLS_LSP_MODE_UNIFORM) ?
+                      MPLS_LABEL_DPO_FLAG_UNIFORM_MODE :
+                      MPLS_LABEL_DPO_FLAG_NONE);
+		FIB_TEST_LB((mpls_label_dpo_get_type(mf) == dpo->dpoi_type),
 			   "bucket %d stacks on %U",
 			   bucket,
 			   format_dpo_type, dpo->dpoi_type);
-	    
+
 		mld = mpls_label_dpo_get(dpo->dpoi_index);
                 hdr = clib_net_to_host_u32(mld->mld_hdr[0].label_exp_s_ttl);
 
@@ -515,15 +527,15 @@ fib_test_validate_lb_v (const load_balance_t *lb,
 			bucket,
 			exp->adj.adj);
 	    break;
-	case FT_LB_MPLS_DISP_O_ADJ:
+	case FT_LB_MPLS_DISP_PIPE_O_ADJ:
         {
             const mpls_disp_dpo_t *mdd;
 
-            FIB_TEST_I((DPO_MPLS_DISPOSITION == dpo->dpoi_type),
+            FIB_TEST_I((DPO_MPLS_DISPOSITION_PIPE == dpo->dpoi_type),
 		       "bucket %d stacks on %U",
 		       bucket,
 		       format_dpo_type, dpo->dpoi_type);
-	    
+
             mdd = mpls_disp_dpo_get(dpo->dpoi_index);
 
             dpo = &mdd->mdd_dpo;
@@ -6332,8 +6344,10 @@ fib_test_label (void)
 	    .eos = MPLS_NON_EOS,
 	},
     };
-    mpls_label_t *l99 = NULL;
-    vec_add1(l99, 99);
+    fib_mpls_label_t *l99 = NULL, fml99 = {
+        .fml_value = 99,
+    };
+    vec_add1(l99, fml99);
 
     fib_table_entry_update_one_path(fib_index,
 				    &pfx_1_1_1_1_s_32,
@@ -6371,8 +6385,10 @@ fib_test_label (void)
 	    .adj = ai_mpls_10_10_11_1,
 	},
     };
-    mpls_label_t *l_imp_null = NULL;
-    vec_add1(l_imp_null, MPLS_IETF_IMPLICIT_NULL_LABEL);
+    fib_mpls_label_t *l_imp_null = NULL, fml_imp_null = {
+        .fml_value =  MPLS_IETF_IMPLICIT_NULL_LABEL,
+    };
+    vec_add1(l_imp_null, fml_imp_null);
 
     fei = fib_table_entry_path_add(fib_index,
 				   &pfx_1_1_1_1_s_32,
@@ -6413,7 +6429,7 @@ fib_test_label (void)
 	.fp_eos = MPLS_NON_EOS,
     };
     fib_test_lb_bucket_t disp_o_10_10_11_1 = {
-	.type = FT_LB_MPLS_DISP_O_ADJ,
+	.type = FT_LB_MPLS_DISP_PIPE_O_ADJ,
 	.adj = {
 	    .adj = ai_v4_10_10_11_1,
 	},
@@ -6458,7 +6474,7 @@ fib_test_label (void)
 	},
     };
     fib_test_lb_bucket_t disp_o_10_10_11_2 = {
-	.type = FT_LB_MPLS_DISP_O_ADJ,
+	.type = FT_LB_MPLS_DISP_PIPE_O_ADJ,
 	.adj = {
 	    .adj = ai_v4_10_10_11_2,
 	},
@@ -6540,24 +6556,27 @@ fib_test_label (void)
 	    .lb = non_eos_1_1_1_1.dpoi_index,
 	    .label = 1600,
 	    .eos = MPLS_EOS,
+            .mode = FIB_MPLS_LSP_MODE_UNIFORM,
 	},
     };
-    mpls_label_t *l1600 = NULL;
-    vec_add1(l1600, 1600);
+    fib_mpls_label_t *l1600 = NULL, fml1600 = {
+        .fml_value = 1600,
+        .fml_mode = FIB_MPLS_LSP_MODE_UNIFORM,
+    };
+    vec_add1(l1600, fml1600);
 
-    fib_table_entry_update_one_path(fib_index,
-				    &pfx_2_2_2_2_s_32,
-				    FIB_SOURCE_API,
-				    FIB_ENTRY_FLAG_NONE,
-				    DPO_PROTO_IP4,
-				    &pfx_1_1_1_1_s_32.fp_addr,
-				    ~0,
-				    fib_index,
-				    1,
-				    l1600,
-				    FIB_ROUTE_PATH_FLAG_NONE);
+    fei = fib_table_entry_update_one_path(fib_index,
+                                          &pfx_2_2_2_2_s_32,
+                                          FIB_SOURCE_API,
+                                          FIB_ENTRY_FLAG_NONE,
+                                          DPO_PROTO_IP4,
+                                          &pfx_1_1_1_1_s_32.fp_addr,
+                                          ~0,
+                                          fib_index,
+                                          1,
+                                          l1600,
+                                          FIB_ROUTE_PATH_FLAG_NONE);
 
-    fei = fib_table_lookup(fib_index, &pfx_2_2_2_2_s_32);
     FIB_TEST(fib_test_validate_entry(fei, 
 				     FIB_FORW_CHAIN_TYPE_UNICAST_IP4,
 				     1,
@@ -6811,7 +6830,7 @@ fib_test_label (void)
      * add back the path with the valid label
      */
     l99 = NULL;
-    vec_add1(l99, 99);
+    vec_add1(l99, fml99);
 
     fib_table_entry_path_add(fib_index,
 			     &pfx_1_1_1_1_s_32,
@@ -6941,8 +6960,10 @@ fib_test_label (void)
 	    .eos = MPLS_EOS,
 	},
     };
-    mpls_label_t *l101 = NULL;
-    vec_add1(l101, 101);
+    fib_mpls_label_t *l101 = NULL, fml101 = {
+        .fml_value = 101,
+    };
+    vec_add1(l101, fml101);
 
     fei = fib_table_entry_update_one_path(fib_index,
 					  &pfx_1_1_1_2_s_32,
@@ -6981,8 +7002,10 @@ fib_test_label (void)
     	    .eos = MPLS_EOS,
     	},
     };
-    mpls_label_t *l1601 = NULL;
-    vec_add1(l1601, 1601);
+    fib_mpls_label_t *l1601 = NULL, fml1601 = {
+        .fml_value = 1601,
+    };
+    vec_add1(l1601, fml1601);
 
     l1600_eos_o_1_1_1_1.label_o_lb.lb = non_eos_1_1_1_1.dpoi_index;
 
@@ -7012,7 +7035,7 @@ fib_test_label (void)
      * the LB for the recursive can use an imp-null
      */
     l_imp_null = NULL;
-    vec_add1(l_imp_null, MPLS_IETF_IMPLICIT_NULL_LABEL);
+    vec_add1(l_imp_null, fml_imp_null);
 
     fei = fib_table_entry_update_one_path(fib_index,
 					  &pfx_1_1_1_2_s_32,
@@ -7176,11 +7199,11 @@ fib_test_label (void)
 	    .eos = MPLS_EOS,
 	},
     };
-    mpls_label_t *label_stack = NULL;
+    fib_mpls_label_t *label_stack = NULL;
     vec_validate(label_stack, 7);
     for (ii = 0; ii < 8; ii++)
     {
-	label_stack[ii] = ii + 200;
+	label_stack[ii].fml_value = ii + 200;
     }
 
     fei = fib_table_entry_update_one_path(fib_index,
@@ -8255,12 +8278,13 @@ static int
 lfib_test (void)
 {
     const mpls_label_t deag_label = 50;
+    dpo_id_t dpo = DPO_INVALID;
+    const mpls_disp_dpo_t *mdd;
     const u32 lfib_index = 0;
     const u32 fib_index = 0;
-    dpo_id_t dpo = DPO_INVALID;
+    const lookup_dpo_t *lkd;
     const dpo_id_t *dpo1;
     fib_node_index_t lfe;
-    lookup_dpo_t *lkd;
     test_main_t *tm;
     int lb_count;
     adj_index_t ai_mpls_10_10_10_1;
@@ -8327,7 +8351,6 @@ lfib_test (void)
              format_mpls_eos_bit, MPLS_EOS,
              format_dpo_proto, lkd->lkd_proto);
 
-
     /*
      * A route deag route for EOS
      */
@@ -8358,7 +8381,14 @@ lfib_test (void)
 				    FIB_FORW_CHAIN_TYPE_MPLS_EOS,
 				    &dpo);
     dpo1 = load_balance_get_bucket(dpo.dpoi_index, 0);
-    lkd = lookup_dpo_get(dpo1->dpoi_index);
+    mdd = mpls_disp_dpo_get(dpo1->dpoi_index);
+
+    FIB_TEST((FIB_MPLS_LSP_MODE_PIPE == mdd->mdd_mode),
+             "%U/%U disp is pipe mode",
+             format_mpls_unicast_label, deag_label,
+             format_mpls_eos_bit, MPLS_EOS);
+
+    lkd = lookup_dpo_get(mdd->mdd_dpo.dpoi_index);
 
     FIB_TEST((fib_index == lkd->lkd_fib_index),
               "%U/%U is deag in %d %U",
@@ -8383,6 +8413,70 @@ lfib_test (void)
               "%U/%U not present",
               format_mpls_unicast_label, deag_label,
               format_mpls_eos_bit, MPLS_EOS);
+    dpo_reset(&dpo);
+
+    /*
+     * A route deag route for EOS with LSP mode uniform
+     */
+    fib_mpls_label_t *l_pops = NULL, l_pop = {
+        .fml_value = MPLS_LABEL_POP,
+        .fml_mode = FIB_MPLS_LSP_MODE_UNIFORM,
+    };
+    vec_add1(l_pops, l_pop);
+    lfe = fib_table_entry_path_add(lfib_index,
+        			   &pfx,
+        			   FIB_SOURCE_CLI,
+        			   FIB_ENTRY_FLAG_NONE,
+        			   DPO_PROTO_IP4,
+        			   &zero_addr,
+        			   ~0,
+        			   fib_index,
+        			   1,
+        			   l_pops,
+        			   FIB_ROUTE_PATH_FLAG_NONE);
+
+    FIB_TEST((lfe == fib_table_lookup(lfib_index, &pfx)),
+              "%U/%U present",
+              format_mpls_unicast_label, deag_label,
+              format_mpls_eos_bit, MPLS_EOS);
+
+    fib_entry_contribute_forwarding(lfe,
+        			    FIB_FORW_CHAIN_TYPE_MPLS_EOS,
+        			    &dpo);
+    dpo1 = load_balance_get_bucket(dpo.dpoi_index, 0);
+    mdd = mpls_disp_dpo_get(dpo1->dpoi_index);
+
+    FIB_TEST((FIB_MPLS_LSP_MODE_UNIFORM == mdd->mdd_mode),
+             "%U/%U disp is uniform mode",
+             format_mpls_unicast_label, deag_label,
+             format_mpls_eos_bit, MPLS_EOS);
+
+    lkd = lookup_dpo_get(mdd->mdd_dpo.dpoi_index);
+
+    FIB_TEST((fib_index == lkd->lkd_fib_index),
+              "%U/%U is deag in %d %U",
+             format_mpls_unicast_label, deag_label,
+             format_mpls_eos_bit, MPLS_EOS,
+             lkd->lkd_fib_index,
+             format_dpo_id, &dpo, 0);
+    FIB_TEST((LOOKUP_INPUT_DST_ADDR == lkd->lkd_input),
+             "%U/%U is dst deag",
+             format_mpls_unicast_label, deag_label,
+             format_mpls_eos_bit, MPLS_EOS);
+    FIB_TEST((DPO_PROTO_IP4 == lkd->lkd_proto),
+             "%U/%U is %U dst deag",
+             format_mpls_unicast_label, deag_label,
+             format_mpls_eos_bit, MPLS_EOS,
+             format_dpo_proto, lkd->lkd_proto);
+
+    fib_table_entry_delete_index(lfe, FIB_SOURCE_CLI);
+
+    FIB_TEST((FIB_NODE_INDEX_INVALID == fib_table_lookup(lfib_index,
+        						 &pfx)),
+              "%U/%U not present",
+              format_mpls_unicast_label, deag_label,
+              format_mpls_eos_bit, MPLS_EOS);
+    dpo_reset(&dpo);
 
     /*
      * A route deag route for non-EOS
@@ -8460,11 +8554,15 @@ lfib_test (void)
     };
     dpo_id_t neos_1200 = DPO_INVALID;
     dpo_id_t ip_1200 = DPO_INVALID;
-    mpls_label_t *l200 = NULL;
-    vec_add1(l200, 200);
-    vec_add1(l200, 300);
-    vec_add1(l200, 400);
-    vec_add1(l200, 500);
+    fib_mpls_label_t *l200 = NULL;
+    u32 ii;
+    for (ii = 0; ii < 4; ii++)
+    {
+        fib_mpls_label_t fml = {
+            .fml_value = 200 + (ii * 100),
+        };
+        vec_add1(l200, fml);
+    };
 
     lfe = fib_table_entry_update_one_path(fib_index,
 					  &pfx_1200,
@@ -8523,8 +8621,10 @@ lfib_test (void)
     	    .ip4.as_u32 = clib_host_to_net_u32(0x02020204),
     	},
     };
-    mpls_label_t *l999 = NULL;
-    vec_add1(l999, 999);
+    fib_mpls_label_t *l999 = NULL, fml_999 = {
+        .fml_value = 999,
+    };
+    vec_add1(l999, fml_999);
     rpaths[0].frp_label_stack = l999,
 
     fib_table_entry_path_add2(fib_index,
@@ -8690,8 +8790,10 @@ lfib_test (void)
             .adj = idpo.dpoi_index,
         },
     };
-    mpls_label_t *l3300 = NULL;
-    vec_add1(l3300, 3300);
+    fib_mpls_label_t *l3300 = NULL, fml_3300 = {
+        .fml_value = 3300,
+    };
+    vec_add1(l3300, fml_3300);
 
     lfe = fib_table_entry_update_one_path(lfib_index,
 					  &pfx_3500,
@@ -8772,6 +8874,9 @@ lfib_test (void)
                                      0, 1);
     mpls_table_delete(MPLS_FIB_DEFAULT_TABLE_ID, FIB_SOURCE_API);
 
+    FIB_TEST(0 == pool_elts(mpls_disp_dpo_pool),
+	     "mpls_disp_dpo resources freed %d of %d",
+             0, pool_elts(mpls_disp_dpo_pool));
     FIB_TEST(lb_count == pool_elts(load_balance_pool),
 	     "Load-balance resources freed %d of %d",
              lb_count, pool_elts(load_balance_pool));
diff --git a/src/vnet/fib/fib_test.h b/src/vnet/fib/fib_test.h
index 0309b3f2311..8ac068350c4 100644
--- a/src/vnet/fib/fib_test.h
+++ b/src/vnet/fib/fib_test.h
@@ -29,7 +29,7 @@ typedef enum fib_test_lb_bucket_type_t_ {
     FT_LB_LABEL_STACK_O_ADJ,
     FT_LB_LABEL_O_LB,
     FT_LB_O_LB,
-    FT_LB_MPLS_DISP_O_ADJ,
+    FT_LB_MPLS_DISP_PIPE_O_ADJ,
     FT_LB_INTF,
     FT_LB_L2,
     FT_LB_BIER_TABLE,
@@ -47,6 +47,7 @@ typedef struct fib_test_lb_bucket_t_ {
 	{
 	    mpls_eos_bit_t eos;
 	    mpls_label_t label;
+            fib_mpls_lsp_mode_t mode;
 	    u8 ttl;
 	    adj_index_t adj;
 	} label_o_adj;
@@ -54,6 +55,7 @@ typedef struct fib_test_lb_bucket_t_ {
 	{
 	    mpls_eos_bit_t eos;
 	    mpls_label_t label_stack[8];
+            fib_mpls_lsp_mode_t mode;
 	    u8 label_stack_size;
 	    u8 ttl;
 	    adj_index_t adj;
@@ -62,6 +64,7 @@ typedef struct fib_test_lb_bucket_t_ {
 	{
 	    mpls_eos_bit_t eos;
 	    mpls_label_t label;
+            fib_mpls_lsp_mode_t mode;
 	    u8 ttl;
 	    index_t lb;
 	} label_o_lb;
diff --git a/src/vnet/fib/fib_types.api b/src/vnet/fib/fib_types.api
index 61a0898819d..fde2c337190 100644
--- a/src/vnet/fib/fib_types.api
+++ b/src/vnet/fib/fib_types.api
@@ -12,6 +12,16 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+ 
+/** \brief MPLS label
+*/
+typeonly define fib_mpls_label
+{
+  u8 is_uniform;
+  u32 label;
+  u8 ttl;
+  u8 exp;
+};
 
 /** \brief FIB path
     @param sw_if_index - index of the interface
@@ -20,6 +30,8 @@
     is prefered
     @param is_local - local if non-zero, else remote
     @param is_drop - Drop the packet
+    @param is_unreach - Drop the packet and rate limit send ICMP unreachable
+    @param is_prohibit - Drop the packet and rate limit send ICMP prohibited
     @param is_udp_encap - The path describes a UDP-o-IP encapsulation.
     @param afi - the afi of the next hop, IP46_TYPE_IP4=1, IP46_TYPE_IP6=2
     @param next_hop[16] - the next hop address
@@ -27,7 +39,7 @@
                          that has a unique identifier. e.g. the UDP
                          encap object
 */
-typeonly define fib_path3
+typeonly define fib_path
 {
   u32 sw_if_index;
   u32 table_id;
@@ -36,10 +48,12 @@ typeonly define fib_path3
   u8 is_local;
   u8 is_drop;
   u8 is_udp_encap;
+  u8 is_unreach;
+  u8 is_prohibit;
   u8 afi;
   u8 next_hop[16];
   u32 next_hop_id;
   u32 rpf_id;
   u8 n_labels;
-  u32 label_stack[16];
+  vl_api_fib_mpls_label_t label_stack[16];
 };
diff --git a/src/vnet/fib/fib_types.c b/src/vnet/fib/fib_types.c
index f38c8154e0c..8b1faf5fa86 100644
--- a/src/vnet/fib/fib_types.c
+++ b/src/vnet/fib/fib_types.c
@@ -25,6 +25,7 @@
 static const char* fib_protocol_names[] = FIB_PROTOCOLS;
 static const char* vnet_link_names[] = VNET_LINKS;
 static const char* fib_forw_chain_names[] = FIB_FORW_CHAINS;
+static const char* fib_mpls_lsp_mode_names[] = FIB_MPLS_LSP_MODES;
 
 u8 *
 format_fib_protocol (u8 * s, va_list * ap)
@@ -50,6 +51,30 @@ format_fib_forw_chain_type (u8 * s, va_list * args)
     return (format (s, "%s", fib_forw_chain_names[fct]));
 }
 
+u8 *
+format_fib_mpls_lsp_mode(u8 *s, va_list *ap)
+{
+    fib_mpls_lsp_mode_t mode = va_arg(*ap, int);
+
+    return (format (s, "%s", fib_mpls_lsp_mode_names[mode])); 
+}
+
+u8 *
+format_fib_mpls_label (u8 *s, va_list *ap)
+{
+    fib_mpls_label_t *label = va_arg(*ap, fib_mpls_label_t *);
+
+    s = format(s, "%U %U ttl:%d exp:%d",
+               format_mpls_unicast_label,
+               label->fml_value,
+               format_fib_mpls_lsp_mode,
+               label->fml_mode,
+               label->fml_ttl,
+               label->fml_exp);
+
+    return (s);
+}
+
 void
 fib_prefix_from_ip46_addr (const ip46_address_t *addr,
 			   fib_prefix_t *pfx)
@@ -307,6 +332,29 @@ fib_forw_chain_type_to_link_type (fib_forward_chain_type_t fct)
     return (VNET_LINK_IP4);
 }
 
+fib_forward_chain_type_t
+fib_forw_chain_type_from_link_type (vnet_link_t link_type)
+{
+    switch (link_type)
+    {
+    case VNET_LINK_IP4:
+        return (FIB_FORW_CHAIN_TYPE_UNICAST_IP4);
+    case VNET_LINK_IP6:
+        return (FIB_FORW_CHAIN_TYPE_UNICAST_IP6);
+    case VNET_LINK_MPLS:
+        return (FIB_FORW_CHAIN_TYPE_MPLS_NON_EOS);
+    case VNET_LINK_ETHERNET:
+        return (FIB_FORW_CHAIN_TYPE_ETHERNET);
+    case VNET_LINK_NSH:
+        return (FIB_FORW_CHAIN_TYPE_NSH);
+    case VNET_LINK_ARP:
+        break;
+    }
+
+    ASSERT(0);
+    return (FIB_FORW_CHAIN_TYPE_UNICAST_IP4);
+}
+
 dpo_proto_t
 fib_forw_chain_type_to_dpo_proto (fib_forward_chain_type_t fct)
 {
@@ -475,7 +523,10 @@ unformat_fib_route_path (unformat_input_t * input, va_list * args)
             while (unformat (input, "%U",
                              unformat_mpls_unicast_label, &out_label))
             {
-                vec_add1(rpath->frp_label_stack, out_label);
+                fib_mpls_label_t fml = {
+                    .fml_value = out_label,
+                };
+                vec_add1(rpath->frp_label_stack, fml);
             }
         }
         else if (unformat (input, "%U",
diff --git a/src/vnet/fib/fib_types.h b/src/vnet/fib/fib_types.h
index 75ed7799f12..7f186ac6f6a 100644
--- a/src/vnet/fib/fib_types.h
+++ b/src/vnet/fib/fib_types.h
@@ -163,11 +163,16 @@ typedef enum fib_forward_chain_type_t_ {
 	 _item++)
 
 /**
- * @brief Convert from a chain type to the adjacencies link type
+ * @brief Convert from a chain type to the adjacency's link type
  */
 extern vnet_link_t fib_forw_chain_type_to_link_type(fib_forward_chain_type_t fct);
 
 /**
+ * @brief Convert from a adjacency's link type to chain type
+ */
+extern fib_forward_chain_type_t fib_forw_chain_type_from_link_type(vnet_link_t lt);
+
+/**
  * @brief Convert from a payload-protocol to a chain type.
  */
 extern fib_forward_chain_type_t fib_forw_chain_type_from_dpo_proto(dpo_proto_t proto);
@@ -373,6 +378,64 @@ typedef u32 fib_rpf_id_t;
 #define MFIB_RPF_ID_NONE (0)
 
 /**
+ * MPLS LSP mode - only valid at the head and tail
+ */
+typedef enum fib_mpls_lsp_mode_t_
+{
+    /**
+     * Pipe Mode - the default.
+     *  TTL and DSCP markings are not carried between the layers
+     */
+    FIB_MPLS_LSP_MODE_PIPE,
+    /**
+     * Uniform mode.
+     *  TTL and DSCP are copied between the layers
+     */
+    FIB_MPLS_LSP_MODE_UNIFORM,
+} __attribute__((packed)) fib_mpls_lsp_mode_t;
+
+#define FIB_MPLS_LSP_MODES {			\
+    [FIB_MPLS_LSP_MODE_PIPE]     = "pipe",     	\
+    [FIB_MPLS_LSP_MODE_UNIFORM]  = "uniform",   \
+}
+
+/**
+ * Format an LSP mode type
+ */
+extern u8 * format_fib_mpls_lsp_mode(u8 *s, va_list *ap);
+
+/**
+ * Configuration for each label value in the output-stack
+ */
+typedef struct fib_mpls_label_t_
+{
+    /**
+     * The label value
+     */
+    mpls_label_t fml_value;
+
+    /**
+     * The LSP mode
+     */
+    fib_mpls_lsp_mode_t fml_mode;
+
+    /**
+     * TTL. valid only at imposition.
+     */
+    u8 fml_ttl;
+
+    /**
+     * EXP bits; valid only at imposition.
+     */
+    u8 fml_exp;
+} fib_mpls_label_t;
+
+/**
+ * Format an MPLS label
+ */
+extern u8 * format_fib_mpls_label(u8 *s, va_list *ap);
+
+/**
  * @brief 
  * A representation of a path as described by a route producer.
  * These paramenters will determine the path 'type', of which there are:
@@ -444,7 +507,7 @@ typedef struct fib_route_path_t_ {
             /**
              * The outgoing MPLS label Stack. NULL implies no label.
              */
-            mpls_label_t *frp_label_stack;
+            fib_mpls_label_t *frp_label_stack;
         };
         /**
          * A path that resolves via a BIER Table.