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diff --git a/src/vnet/fib/fib_urpf_list.h b/src/vnet/fib/fib_urpf_list.h
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+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * @brief A unicast RPF list.
+ * The uRPF list is the set of interfaces that a prefix can be reached through.
+ * There are 3 levels of RPF check:
+ *   - do we have any route to the source (i.e. it's not drop)
+ *   - did the packet arrive on an interface that the source is reachable through
+ *   - did the packet arrive from a peer that the source is reachable through
+ * we don't support the last. But it could be done by storing adjs in the uPRF
+ * list rather than interface indices.
+ *
+ * these conditions are checked against the list by:
+ *   - the list is not empty
+ *   - there is an interface in the list that is on the input interface.
+ *   - there is an adj in the list whose MAC address matches the packet's
+ *     source MAC and input interface.
+ *
+ * To speed the last two checks the interface list only needs to have the unique
+ * interfaces present. If the uRPF check was instead implemented by forward
+ * walking the DPO chain, then that walk would encounter a great deal of
+ * non-adjacency objects (i.e. load-balances, mpls-labels, etc) and potentially
+ * the same adjacency many times (esp. when UCMP is used).
+ * To that end the uRPF list is a collapsed, unique interface only list.
+ */
+
+#ifndef __FIB_URPF_LIST_H__
+#define __FIB_URPF_LIST_H__
+
+#include <vnet/fib/fib_types.h>
+#include <vnet/adj/adj.h>
+
+/**
+ * @brief flags
+ */
+typedef enum fib_urpf_list_flag_t_
+{
+    /**
+     * @brief Set to indicated that the uRPF list has already been baked.
+     * This is protection against it being baked more than once. These
+     * are not chunky fries - once is enough.
+     */
+    FIB_URPF_LIST_BAKED = (1 << 0),
+} fib_urpf_list_flag_t;
+
+typedef struct fib_urpf_list_t_
+{
+    /**
+     * The list of interfaces that comprise the allowed accepting interfaces
+     */
+    adj_index_t *furpf_itfs;
+
+    /**
+     * flags
+     */
+    fib_urpf_list_flag_t furpf_flags;
+
+    /**
+     * uRPF lists are shared amongst many entries so we require a locking
+     * mechanism.
+     */
+    u32 furpf_locks;
+} fib_urpf_list_t;
+
+extern index_t fib_urpf_list_alloc_and_lock(void);
+extern void fib_urpf_list_unlock(index_t urpf);
+extern void fib_urpf_list_lock(index_t urpf);
+
+extern void fib_urpf_list_append(index_t urpf, adj_index_t adj);
+extern void fib_urpf_list_combine(index_t urpf1, index_t urpf2);
+
+extern void fib_urpf_list_bake(index_t urpf);
+
+extern u8 *format_fib_urpf_list(u8 *s, va_list ap);
+
+extern void fib_urpf_list_show_mem(void);
+
+/**
+ * @brief pool of all fib_urpf_list
+ */
+extern fib_urpf_list_t *fib_urpf_list_pool;
+
+static inline fib_urpf_list_t *
+fib_urpf_list_get (index_t index)
+{
+    return (pool_elt_at_index(fib_urpf_list_pool, index));
+}
+
+/**
+ * @brief Data-Plane function to check an input interface against an uRPF list
+ *
+ * @param ui The uRPF list index to check against. Get this from the load-balance
+ *             object that is the result of the FIB lookup
+ * @param sw_if_index The SW interface index to validate
+ *
+ * @return 1 if the interface is found, 0 otherwise
+ */
+always_inline int
+fib_urpf_check (index_t ui, u32 sw_if_index)
+{
+    fib_urpf_list_t *urpf;
+    u32 *swi;
+
+    urpf = fib_urpf_list_get(ui);
+
+    vec_foreach(swi, urpf->furpf_itfs)
+    {
+	if (*swi == sw_if_index)
+	    return (1);
+    }
+
+    return (0);
+}
+
+/**
+ * @brief Data-Plane function to check the size of an uRPF list, (i.e. the number
+ *        of interfaces in the list).
+ *
+ * @param ui The uRPF list index to check against. Get this from the load-balance
+ *             object that is the result of the FIB lookup
+ *
+ * @return the number of interfaces in the list
+ */
+always_inline int
+fib_urpf_check_size (index_t ui)
+{
+    fib_urpf_list_t *urpf;
+
+    urpf = fib_urpf_list_get(ui);
+
+    return (vec_len(urpf->furpf_itfs));
+}
+
+#endif