5 files changed, 114 insertions, 26 deletions

diff --git a/src/vnet/dpo/dpo.c b/src/vnet/dpo/dpo.c
index 85f2c5d3622..19e3714c536 100644
--- a/src/vnet/dpo/dpo.c
+++ b/src/vnet/dpo/dpo.c
@@ -153,20 +153,22 @@ format_dpo_id (u8 * s, va_list * args)
 
     if (NULL != dpo_vfts[dpo->dpoi_type].dv_format)
     {
-        return (format(s, "%U",
-                       dpo_vfts[dpo->dpoi_type].dv_format,
-                       dpo->dpoi_index,
-                       indent));
+        s = format(s, "%U",
+                   dpo_vfts[dpo->dpoi_type].dv_format,
+                   dpo->dpoi_index,
+                   indent);
     }
-
-    switch (dpo->dpoi_type)
+    else
     {
-    case DPO_FIRST:
-	s = format(s, "unset");
-	break;
-    default:
-	s = format(s, "unknown");
-	break;
+        switch (dpo->dpoi_type)
+        {
+        case DPO_FIRST:
+            s = format(s, "unset");
+            break;
+        default:
+            s = format(s, "unknown");
+            break;
+        }
     }
     return (s);
 }
@@ -303,6 +305,18 @@ dpo_default_get_next_node (const dpo_id_t *dpo)
     return (node_indices);
 }
 
+/**
+ * A default variant of the make interpose function that just returns
+ * the original
+ */
+static void
+dpo_default_mk_interpose (const dpo_id_t *original,
+                          const dpo_id_t *parent,
+                          dpo_id_t *clone)
+{
+    dpo_copy(clone, original);
+}
+
 void
 dpo_register (dpo_type_t type,
 	      const dpo_vft_t *vft,
@@ -314,6 +328,10 @@ dpo_register (dpo_type_t type,
     {
         dpo_vfts[type].dv_get_next_node = dpo_default_get_next_node;
     }
+    if (NULL == dpo_vfts[type].dv_mk_interpose)
+    {
+        dpo_vfts[type].dv_mk_interpose = dpo_default_mk_interpose;
+    }
 
     vec_validate(dpo_nodes, type);
     dpo_nodes[type] = nodes;
@@ -331,6 +349,17 @@ dpo_register_new_type (const dpo_vft_t *vft,
 }
 
 void
+dpo_mk_interpose (const dpo_id_t *original,
+                  const dpo_id_t *parent,
+                  dpo_id_t *clone)
+{
+    if (!dpo_id_is_valid(original))
+	return;
+
+    dpo_vfts[original->dpoi_type].dv_mk_interpose(original, parent, clone);
+}
+
+void
 dpo_lock (dpo_id_t *dpo)
 {
     if (!dpo_id_is_valid(dpo))
diff --git a/src/vnet/dpo/dpo.h b/src/vnet/dpo/dpo.h
index 21a2ae2a33d..0eeca67b74b 100644
--- a/src/vnet/dpo/dpo.h
+++ b/src/vnet/dpo/dpo.h
@@ -225,6 +225,14 @@ extern void dpo_lock(dpo_id_t *dpo);
 extern void dpo_unlock(dpo_id_t *dpo);
 
 /**
+ * @brief
+ *  Make an interpose DPO from an original
+ */
+extern void dpo_mk_interpose(const dpo_id_t *original,
+                             const dpo_id_t *parent,
+                             dpo_id_t *clone);
+
+/**
  * @brief Set/create a DPO ID
  * The DPO will be locked.
  *
@@ -374,6 +382,18 @@ typedef u32* (*dpo_get_next_node_t)(const dpo_id_t *dpo);
 typedef u32 (*dpo_get_urpf_t)(const dpo_id_t *dpo);
 
 /**
+ * @brief Called during FIB interposition when the originally
+ * registered DPO is used to 'clone' an instance for interposition
+ * at a particular location in the FIB graph.
+ * The parent is the next DPO in the chain that the clone will
+ * be used instead of. The clone may then choose to stack itself
+ * on the parent.
+ */
+typedef void (*dpo_mk_interpose_t)(const dpo_id_t *original,
+                                   const dpo_id_t *parent,
+                                   dpo_id_t *clone);
+
+/**
  * @brief A virtual function table regisitered for a DPO type
  */
 typedef struct dpo_vft_t_
@@ -405,6 +425,10 @@ typedef struct dpo_vft_t_
      * Get uRPF interface
      */
     dpo_get_urpf_t dv_get_urpf;
+    /**
+     * Signal on an interposed child that the parent has changed
+     */
+    dpo_mk_interpose_t dv_mk_interpose;
 } dpo_vft_t;
 
 
diff --git a/src/vnet/dpo/load_balance.c b/src/vnet/dpo/load_balance.c
index db0ebcdceb8..bb38233a55e 100644
--- a/src/vnet/dpo/load_balance.c
+++ b/src/vnet/dpo/load_balance.c
@@ -198,16 +198,6 @@ load_balance_create (u32 n_buckets,
     return (load_balance_get_index(load_balance_create_i(n_buckets, lb_proto, fhc)));
 }
 
-u16
-load_balance_n_buckets (index_t lbi)
-{
-    load_balance_t *lb;
-
-    lb = load_balance_get(lbi);
-
-    return (lb->lb_n_buckets);
-}
-
 static inline void
 load_balance_set_bucket_i (load_balance_t *lb,
                            u32 bucket,
@@ -250,6 +240,16 @@ load_balance_is_drop (const dpo_id_t *dpo)
     return (0);
 }
 
+u16
+load_balance_n_buckets (index_t lbi)
+{
+    load_balance_t *lb;
+
+    lb = load_balance_get(lbi);
+
+    return (lb->lb_n_buckets);
+}
+
 void
 load_balance_set_fib_entry_flags (index_t lbi,
                                   fib_entry_flag_t flags)
diff --git a/src/vnet/dpo/mpls_label_dpo.c b/src/vnet/dpo/mpls_label_dpo.c
index ebbbbec9b64..0a7063cc99a 100644
--- a/src/vnet/dpo/mpls_label_dpo.c
+++ b/src/vnet/dpo/mpls_label_dpo.c
@@ -1204,11 +1204,44 @@ mpls_label_dpo_mem_show (void)
 			  sizeof(mpls_label_dpo_t));
 }
 
+/**
+ * Interpose a label DPO. used in the FIB unit tests
+ */
+static void
+mpls_label_interpose (const dpo_id_t *original,
+                      const dpo_id_t *parent,
+                      dpo_id_t *clone)
+{
+    mpls_label_dpo_t *mld, *mld_clone;
+
+    mld_clone = mpls_label_dpo_alloc();
+    mld = mpls_label_dpo_get(original->dpoi_index);
+
+    mld_clone->mld_locks = 0;
+    clib_memcpy(&mld_clone->mld_hdr,
+                &mld->mld_hdr,
+                sizeof(mld_clone->mld_hdr));
+    mld_clone->mld_payload_proto = mld->mld_payload_proto;
+    mld_clone->mld_n_labels = mld->mld_n_labels;
+    mld_clone->mld_n_hdr_bytes = mld->mld_n_hdr_bytes;
+
+    dpo_stack(mpls_label_dpo_types[MPLS_LABEL_DPO_FLAG_NONE],
+              mld_clone->mld_payload_proto,
+              &mld_clone->mld_dpo,
+              parent);
+
+    dpo_set(clone,
+            mpls_label_dpo_types[MPLS_LABEL_DPO_FLAG_NONE],
+            mld_clone->mld_payload_proto,
+            mpls_label_dpo_get_index(mld_clone));
+}
+
 const static dpo_vft_t mld_vft = {
     .dv_lock = mpls_label_dpo_lock,
     .dv_unlock = mpls_label_dpo_unlock,
     .dv_format = format_mpls_label_dpo,
     .dv_mem_show = mpls_label_dpo_mem_show,
+    .dv_mk_interpose = mpls_label_interpose,
 };
 
 const static char* const mpls_label_imp_pipe_ip4_nodes[] =
diff --git a/src/vnet/dpo/replicate_dpo.h b/src/vnet/dpo/replicate_dpo.h
index 7383184a2ea..ccb25630e16 100644
--- a/src/vnet/dpo/replicate_dpo.h
+++ b/src/vnet/dpo/replicate_dpo.h
@@ -53,7 +53,7 @@ extern replicate_main_t replicate_main;
  */
 typedef struct replicate_t_ {
     /**
-     * number of buckets in the load-balance. always a power of 2.
+     * number of buckets in the replicate.
      */
     u16 rep_n_buckets;
 
@@ -104,15 +104,17 @@ extern void replicate_multipath_update(
     load_balance_path_t *next_hops);
 
 extern void replicate_set_bucket(index_t repi,
-				    u32 bucket,
-				    const dpo_id_t *next);
+                                 u32 bucket,
+                                 const dpo_id_t *next);
 
 extern u8* format_replicate(u8 * s, va_list * args);
 
 extern const dpo_id_t *replicate_get_bucket(index_t repi,
-					       u32 bucket);
+                                            u32 bucket);
 extern int replicate_is_drop(const dpo_id_t *dpo);
 
+extern u16 replicate_n_buckets(index_t repi);
+
 /**
  * The encapsulation breakages are for fast DP access
  */