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#!/usr/bin/env python
# Copyright (c) 2016 Comcast Cable Communications Management, LLC.
#
# 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.

# Looks for preprocessor macros with struct initializers and siphons them
# off into another file for later parsing; ostensibly to generate
# documentation from struct initializer data.

import os, sys, argparse, logging
import siphon

DEFAULT_LOGFILE = None
DEFAULT_LOGLEVEL = "info"
DEFAULT_OUTPUT = "build-root/docs/siphons"
DEFAULT_PREFIX = os.getcwd()

ap = argparse.ArgumentParser()
ap.add_argument("--log-file", default=DEFAULT_LOGFILE,
        help="Log file [%s]" % DEFAULT_LOGFILE)
ap.add_argument("--log-level", default=DEFAULT_LOGLEVEL,
        choices=["debug", "info", "warning", "error", "critical"],
        help="Logging level [%s]" % DEFAULT_LOGLEVEL)

ap.add_argument("--output", '-o', metavar="directory", default=DEFAULT_OUTPUT,
        help="Output directory for .siphon files [%s]" % DEFAULT_OUTPUT)
ap.add_argument("--input-prefix", metavar="path", default=DEFAULT_PREFIX,
        help="Prefix to strip from input pathnames [%s]" % DEFAULT_PREFIX)
ap.add_argument("input", nargs='+', metavar="input_file",
        help="Input C source files")
args = ap.parse_args()

logging.basicConfig(filename=args.log_file,
        level=getattr(logging, args.log_level.upper(), None))
log = logging.getLogger("siphon_generate")


generate = siphon.generate.Generate(output_directory=args.output,
    input_prefix=args.input_prefix)

# Pre-process file names in case they indicate a file with
# a list of files
files = []
for filename in args.input:
    if filename.startswith('@'):
        with open(filename[1:], 'r') as fp:
            lines = fp.readlines()
            for line in lines:
                file = line.strip()
                if file not in files:
                    files.append(file)
            lines = None
    else:
        if filename not in files:
            files.append(filename)

# Iterate all the input files we've been given
for filename in files:
    generate.parse(filename)

# Write the extracted data
generate.deliver()

# All done
'#n658'>658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 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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.
 */

#include <vlib/vlib.h>
#include <vnet/ip/format.h>
#include <vnet/ip/lookup.h>
#include <vnet/adj/adj.h>
#include <vnet/dpo/load_balance.h>
#include <vnet/dpo/drop_dpo.h>

#include <vnet/fib/fib_entry.h>
#include <vnet/fib/fib_walk.h>
#include <vnet/fib/fib_entry_src.h>
#include <vnet/fib/fib_entry_cover.h>
#include <vnet/fib/fib_table.h>
#include <vnet/fib/fib_internal.h>
#include <vnet/fib/fib_attached_export.h>
#include <vnet/fib/fib_path_ext.h>
#include <vnet/fib/fib_entry_delegate.h>
#include <vnet/fib/fib_entry_track.h>

/*
 * Array of strings/names for the FIB sources
 */
static const char *fib_attribute_names[] = FIB_ENTRY_ATTRIBUTES;
static const char *fib_src_attribute_names[] = FIB_ENTRY_SRC_ATTRIBUTES;

/*
 * Pool for all fib_entries
 */
static fib_entry_t *fib_entry_pool;

/**
 * the logger
 */
vlib_log_class_t fib_entry_logger;

fib_entry_t *
fib_entry_get (fib_node_index_t index)
{
    return (pool_elt_at_index(fib_entry_pool, index));
}

static fib_node_t *
fib_entry_get_node (fib_node_index_t index)
{
    return ((fib_node_t*)fib_entry_get(index));
}

fib_node_index_t
fib_entry_get_index (const fib_entry_t * fib_entry)
{
    return (fib_entry - fib_entry_pool);
}

fib_protocol_t
fib_entry_get_proto (const fib_entry_t * fib_entry)
{
    return (fib_entry->fe_prefix.fp_proto);
}

dpo_proto_t
fib_entry_get_dpo_proto (const fib_entry_t * fib_entry)
{
    return (fib_proto_to_dpo(fib_entry->fe_prefix.fp_proto));
}

fib_forward_chain_type_t
fib_entry_get_default_chain_type (const fib_entry_t *fib_entry)
{
    switch (fib_entry->fe_prefix.fp_proto)
    {
    case FIB_PROTOCOL_IP4:
	return (FIB_FORW_CHAIN_TYPE_UNICAST_IP4);
    case FIB_PROTOCOL_IP6:
	return (FIB_FORW_CHAIN_TYPE_UNICAST_IP6);
    case FIB_PROTOCOL_MPLS:
	if (MPLS_EOS == fib_entry->fe_prefix.fp_eos)
	    return (FIB_FORW_CHAIN_TYPE_MPLS_EOS);
	else
	    return (FIB_FORW_CHAIN_TYPE_MPLS_NON_EOS);
    }

    return (FIB_FORW_CHAIN_TYPE_UNICAST_IP4);
}

u8 *
format_fib_entry_flags (u8 *s, va_list *args)
{
    fib_entry_attribute_t attr;
    fib_entry_flag_t flag = va_arg(*args, int);

    FOR_EACH_FIB_ATTRIBUTE(attr) {
        if ((1<<attr) & flag) {
            s = format (s, "%s,", fib_attribute_names[attr]);
        }
    }

    return (s);
}

u8 *
format_fib_entry_src_flags (u8 *s, va_list *args)
{
    fib_entry_src_attribute_t sattr;
    fib_entry_src_flag_t flag = va_arg(*args, int);

    FOR_EACH_FIB_SRC_ATTRIBUTE(sattr) {
        if ((1<<sattr) & flag) {
            s = format (s, "%s,", fib_src_attribute_names[sattr]);
        }
    }

    return (s);
}

u8 *
format_fib_entry (u8 * s, va_list * args)
{
    fib_forward_chain_type_t fct;
    fib_entry_t *fib_entry;
    fib_entry_src_t *src;
    fib_node_index_t fei;
    fib_source_t source;
    int level;

    fei = va_arg (*args, fib_node_index_t);
    level = va_arg (*args, int);
    fib_entry = fib_entry_get(fei);

    s = format (s, "%U", format_fib_prefix, &fib_entry->fe_prefix);

    if (level >= FIB_ENTRY_FORMAT_DETAIL)
    {
	s = format (s, " fib:%d", fib_entry->fe_fib_index);
	s = format (s, " index:%d", fib_entry_get_index(fib_entry));
	s = format (s, " locks:%d", fib_entry->fe_node.fn_locks);

	FOR_EACH_SRC_ADDED(fib_entry, src, source,
        ({
	    s = format (s, "\n  %U", format_fib_source, source);
	    s = format (s, " refs:%d", src->fes_ref_count);
	    if (FIB_ENTRY_FLAG_NONE != src->fes_entry_flags) {
		s = format(s, " entry-flags:%U",
                           format_fib_entry_flags, src->fes_entry_flags);
	    }
	    if (FIB_ENTRY_SRC_FLAG_NONE != src->fes_flags) {
		s = format(s, " src-flags:%U",
                           format_fib_entry_src_flags, src->fes_flags);
	    }
            s = fib_entry_src_format(fib_entry, source, s);
	    s = format (s, "\n");
	    if (FIB_NODE_INDEX_INVALID != src->fes_pl)
	    {
		s = fib_path_list_format(src->fes_pl, s);
	    }
            s = format(s, "%U", format_fib_path_ext_list, &src->fes_path_exts);
	}));
    
	s = format (s, "\n forwarding: ");
    }
    else
    {
	s = format (s, "\n");
    }

    fct = fib_entry_get_default_chain_type(fib_entry);

    if (!dpo_id_is_valid(&fib_entry->fe_lb))
    {
	s = format (s, "  UNRESOLVED\n");
	return (s);
    }
    else
    {
        s = format(s, "  %U-chain\n  %U",
                   format_fib_forw_chain_type, fct,
                   format_dpo_id,
                   &fib_entry->fe_lb,
                   2);
        s = format(s, "\n");

        if (level >= FIB_ENTRY_FORMAT_DETAIL2)
        {
            index_t *fedi;

            s = format (s, " Delegates:\n");
            vec_foreach(fedi, fib_entry->fe_delegates)
            {
                s = format(s, "  %U\n", format_fib_entry_delegate, *fedi);
            }
        }
    }

    if (level >= FIB_ENTRY_FORMAT_DETAIL2)
    {
        s = format(s, " Children:");
        s = fib_node_children_format(fib_entry->fe_node.fn_children, s);
    }

    return (s);
}

static fib_entry_t*
fib_entry_from_fib_node (fib_node_t *node)
{
    ASSERT(FIB_NODE_TYPE_ENTRY == node->fn_type);
    return ((fib_entry_t*)node);
}

static void
fib_entry_last_lock_gone (fib_node_t *node)
{
    fib_entry_delegate_type_t fdt;
    fib_entry_delegate_t *fed;
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_from_fib_node(node);

    ASSERT(!dpo_id_is_valid(&fib_entry->fe_lb));

    FOR_EACH_DELEGATE_CHAIN(fib_entry, fdt, fed,
    {
	dpo_reset(&fed->fd_dpo);
        fib_entry_delegate_remove(fib_entry, fdt);
    });

    FIB_ENTRY_DBG(fib_entry, "last-lock");

    fib_node_deinit(&fib_entry->fe_node);

    ASSERT(0 == vec_len(fib_entry->fe_delegates));
    vec_free(fib_entry->fe_delegates);
    vec_free(fib_entry->fe_srcs);
    pool_put(fib_entry_pool, fib_entry);
}

static fib_entry_src_t*
fib_entry_get_best_src_i (const fib_entry_t *fib_entry)
{
    fib_entry_src_t *bsrc;

    /*
     * the enum of sources is deliberately arranged in priority order
     */
    if (0 == vec_len(fib_entry->fe_srcs))
    {
	bsrc = NULL;
    }
    else
    {
	bsrc = vec_elt_at_index(fib_entry->fe_srcs, 0);
    }

    return (bsrc);
}

static fib_source_t
fib_entry_src_get_source (const fib_entry_src_t *esrc)
{
    if (NULL != esrc)
    {
	return (esrc->fes_src);
    }
    return (FIB_SOURCE_INVALID);
}

static fib_entry_flag_t
fib_entry_src_get_flags (const fib_entry_src_t *esrc)
{
    if (NULL != esrc)
    {
	return (esrc->fes_entry_flags);
    }
    return (FIB_ENTRY_FLAG_NONE);
}

fib_entry_flag_t
fib_entry_get_flags (fib_node_index_t fib_entry_index)
{
    return (fib_entry_get_flags_i(fib_entry_get(fib_entry_index)));
}

/*
 * fib_entry_back_walk_notify
 *
 * A back walk has reach this entry.
 */
static fib_node_back_walk_rc_t
fib_entry_back_walk_notify (fib_node_t *node,
			    fib_node_back_walk_ctx_t *ctx)
{
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_from_fib_node(node);

    if (FIB_NODE_BW_REASON_FLAG_EVALUATE & ctx->fnbw_reason        ||
        FIB_NODE_BW_REASON_FLAG_ADJ_UPDATE & ctx->fnbw_reason      ||
        FIB_NODE_BW_REASON_FLAG_ADJ_DOWN & ctx->fnbw_reason        ||
	FIB_NODE_BW_REASON_FLAG_INTERFACE_UP & ctx->fnbw_reason    ||
	FIB_NODE_BW_REASON_FLAG_INTERFACE_DOWN & ctx->fnbw_reason  ||
	FIB_NODE_BW_REASON_FLAG_INTERFACE_DELETE & ctx->fnbw_reason)
    {
	fib_entry_src_action_reactivate(fib_entry,
                                        fib_entry_get_best_source(
                                            fib_entry_get_index(fib_entry)));
    }

    /*
     * all other walk types can be reclassifed to a re-evaluate to
     * all recursive dependents.
     * By reclassifying we ensure that should any of these walk types meet
     * they can be merged.
     */
    ctx->fnbw_reason = FIB_NODE_BW_REASON_FLAG_EVALUATE;

    /*
     * ... and nothing is forced sync from now on.
     */
    ctx->fnbw_flags &= ~FIB_NODE_BW_FLAG_FORCE_SYNC;

    FIB_ENTRY_DBG(fib_entry, "bw:%U",
                  format_fib_node_bw_reason, ctx->fnbw_reason);

    /*
     * propagate the backwalk further if we haven't already reached the
     * maximum depth.
     */
    fib_walk_sync(FIB_NODE_TYPE_ENTRY,
		  fib_entry_get_index(fib_entry),
		  ctx);

    return (FIB_NODE_BACK_WALK_CONTINUE);
}

static void
fib_entry_show_memory (void)
{
    u32 n_srcs = 0, n_exts = 0;
    fib_entry_src_t *esrc;
    fib_entry_t *entry;

    fib_show_memory_usage("Entry",
			  pool_elts(fib_entry_pool),
			  pool_len(fib_entry_pool),
			  sizeof(fib_entry_t));

    pool_foreach (entry, fib_entry_pool)
     {
	n_srcs += vec_len(entry->fe_srcs);
	vec_foreach(esrc, entry->fe_srcs)
	{
	    n_exts += fib_path_ext_list_length(&esrc->fes_path_exts);
	}
    }

    fib_show_memory_usage("Entry Source",
			  n_srcs, n_srcs, sizeof(fib_entry_src_t));
    fib_show_memory_usage("Entry Path-Extensions",
			  n_exts, n_exts,
			  sizeof(fib_path_ext_t));
}

/*
 * The FIB path-list's graph node virtual function table
 */
static const fib_node_vft_t fib_entry_vft = {
    .fnv_get = fib_entry_get_node,
    .fnv_last_lock = fib_entry_last_lock_gone,
    .fnv_back_walk = fib_entry_back_walk_notify,
    .fnv_mem_show = fib_entry_show_memory,
};

/**
 * @brief Contribute the set of Adjacencies that this entry forwards with
 * to build the uRPF list of its children
 */
void
fib_entry_contribute_urpf (fib_node_index_t entry_index,
			   index_t urpf)
{
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(entry_index);

    return (fib_path_list_contribute_urpf(fib_entry->fe_parent, urpf));
}

/*
 * If the client is request a chain for multicast forwarding then swap
 * the chain type to one that can provide such transport.
 */
static fib_forward_chain_type_t
fib_entry_chain_type_mcast_to_ucast (fib_forward_chain_type_t fct)
{
    switch (fct)
    {
    case FIB_FORW_CHAIN_TYPE_MCAST_IP4:
    case FIB_FORW_CHAIN_TYPE_MCAST_IP6:
        /*
         * we can only transport IP multicast packets if there is an
         * LSP.
         */
        fct = FIB_FORW_CHAIN_TYPE_MPLS_EOS;
        break;
    case FIB_FORW_CHAIN_TYPE_MPLS_EOS:
    case FIB_FORW_CHAIN_TYPE_UNICAST_IP4:
    case FIB_FORW_CHAIN_TYPE_UNICAST_IP6:
    case FIB_FORW_CHAIN_TYPE_MPLS_NON_EOS:
    case FIB_FORW_CHAIN_TYPE_ETHERNET:
    case FIB_FORW_CHAIN_TYPE_NSH:
    case FIB_FORW_CHAIN_TYPE_BIER:
        break;
    }

    return (fct);
}

/*
 * fib_entry_contribute_forwarding
 *
 * Get an lock the forwarding information (DPO) contributed by the FIB entry.
 */
void
fib_entry_contribute_forwarding (fib_node_index_t fib_entry_index,
				 fib_forward_chain_type_t fct,
				 dpo_id_t *dpo)
{
    fib_entry_delegate_t *fed;
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);

    /*
     * mfib children ask for mcast chains. fix these to the appropriate ucast types.
     */
    fct = fib_entry_chain_type_mcast_to_ucast(fct);

    if (fct == fib_entry_get_default_chain_type(fib_entry))
    {
        dpo_copy(dpo, &fib_entry->fe_lb);
    }
    else
    {
        fed = fib_entry_delegate_find(fib_entry,
                                      fib_entry_chain_type_to_delegate_type(fct));

        if (NULL == fed)
        {
            /*
             * use a temporary DPO lest the delegate realloc in the recursive
             * calculation.
             */
            dpo_id_t tmp = DPO_INVALID;

            /*
             * on-demand create eos/non-eos.
             * There is no on-demand delete because:
             *   - memory versus complexity & reliability:
             *      leaving unrequired [n]eos LB arounds wastes memory, cleaning
             *      then up on the right trigger is more code. i favour the latter.
             */
            fib_entry_src_mk_lb(fib_entry,
                                fib_entry_get_best_source(fib_entry_index),
                                fct,
                                &tmp);

            fed = fib_entry_delegate_find_or_add(
                fib_entry,
                fib_entry_chain_type_to_delegate_type(fct));

            dpo_copy(&fed->fd_dpo, &tmp);
            dpo_reset(&tmp);
        }

        dpo_copy(dpo, &fed->fd_dpo);
    }
    /*
     * use the drop DPO is nothing else is present
     */
    if (!dpo_id_is_valid(dpo))
    {
        dpo_copy(dpo, drop_dpo_get(fib_forw_chain_type_to_dpo_proto(fct)));
    }

    /*
     * don't allow the special index indicating replicate.vs.load-balance
     * to escape to the clients
     */
    dpo->dpoi_index &= ~MPLS_IS_REPLICATE;
}

const dpo_id_t *
fib_entry_contribute_ip_forwarding (fib_node_index_t fib_entry_index)
{
    fib_forward_chain_type_t fct;
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);
    fct = fib_entry_get_default_chain_type(fib_entry);

    ASSERT((fct == FIB_FORW_CHAIN_TYPE_UNICAST_IP4 ||
            fct == FIB_FORW_CHAIN_TYPE_UNICAST_IP6));

    if (dpo_id_is_valid(&fib_entry->fe_lb))
    {
        return (&fib_entry->fe_lb);
    }

    return (drop_dpo_get(fib_forw_chain_type_to_dpo_proto(fct)));
}

adj_index_t
fib_entry_get_adj (fib_node_index_t fib_entry_index)
{
    const dpo_id_t *dpo;

    dpo = fib_entry_contribute_ip_forwarding(fib_entry_index);

    if (dpo_id_is_valid(dpo))
    {
        dpo = load_balance_get_bucket(dpo->dpoi_index, 0);

        if (dpo_is_adj(dpo))
        {
            return (dpo->dpoi_index);
        }
    }
    return (ADJ_INDEX_INVALID);
}

fib_node_index_t
fib_entry_get_path_list (fib_node_index_t fib_entry_index)
{
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);

    return (fib_entry->fe_parent);
}

u32
fib_entry_child_add (fib_node_index_t fib_entry_index,
		     fib_node_type_t child_type,
		     fib_node_index_t child_index)
{
    return (fib_node_child_add(FIB_NODE_TYPE_ENTRY,
                               fib_entry_index,
                               child_type,
                               child_index));
};

void
fib_entry_child_remove (fib_node_index_t fib_entry_index,
			u32 sibling_index)
{
    fib_node_child_remove(FIB_NODE_TYPE_ENTRY,
                          fib_entry_index,
                          sibling_index);

    if (0 == fib_node_get_n_children(FIB_NODE_TYPE_ENTRY,
                                     fib_entry_index))
    {
        /*
         * if there are no children left then there is no reason to keep
         * the non-default forwarding chains. those chains are built only
         * because the children want them.
         */
        fib_entry_delegate_type_t fdt;
        fib_entry_delegate_t *fed;
        fib_entry_t *fib_entry;

        fib_entry = fib_entry_get(fib_entry_index);

        FOR_EACH_DELEGATE_CHAIN(fib_entry, fdt, fed,
        {
            dpo_reset(&fed->fd_dpo);
            fib_entry_delegate_remove(fib_entry, fdt);
        });
    }
}

static fib_entry_t *
fib_entry_alloc (u32 fib_index,
		 const fib_prefix_t *prefix,
		 fib_node_index_t *fib_entry_index)
{
    fib_entry_t *fib_entry;
    fib_prefix_t *fep;
    u8 need_barrier_sync = 0;
    vlib_main_t *vm = vlib_get_main();
    ASSERT (vm->thread_index == 0);

    pool_get_will_expand (fib_entry_pool, need_barrier_sync );
    if (need_barrier_sync)
        vlib_worker_thread_barrier_sync (vm);

    pool_get(fib_entry_pool, fib_entry);

    if (need_barrier_sync)
        vlib_worker_thread_barrier_release (vm);

    clib_memset(fib_entry, 0, sizeof(*fib_entry));

    fib_node_init(&fib_entry->fe_node,
		  FIB_NODE_TYPE_ENTRY);

    fib_entry->fe_fib_index = fib_index;

    /*
     * the one time we need to update the const prefix is when
     * the entry is first created
     */
    fep = (fib_prefix_t*)&(fib_entry->fe_prefix);
    *fep = *prefix;

    if (FIB_PROTOCOL_MPLS == fib_entry->fe_prefix.fp_proto)
    {
	fep->fp_len = 21;
	if (MPLS_NON_EOS == fep->fp_eos)
	{
	    fep->fp_payload_proto = DPO_PROTO_MPLS;
	}
    	ASSERT(DPO_PROTO_NONE != fib_entry->fe_prefix.fp_payload_proto);
    }

    dpo_reset(&fib_entry->fe_lb);

    *fib_entry_index = fib_entry_get_index(fib_entry);

    return (fib_entry);
}

static fib_entry_t*
fib_entry_post_flag_update_actions (fib_entry_t *fib_entry,
				    fib_entry_flag_t old_flags)
{
    fib_node_index_t fei;

    /*
     * save the index so we can recover from pool reallocs
     */
    fei = fib_entry_get_index(fib_entry);

    /*
     * handle changes to attached export for import entries
     */
    int is_import  = (FIB_ENTRY_FLAG_IMPORT & fib_entry_get_flags_i(fib_entry));
    int was_import = (FIB_ENTRY_FLAG_IMPORT & old_flags);

    if (!was_import && is_import)
    {
	/*
	 * transition from not exported to exported
	 */

	/*
	 * there is an assumption here that the entry resolves via only
	 * one interface and that it is the cross VRF interface.
	 */
	u32 sw_if_index = fib_path_list_get_resolving_interface(fib_entry->fe_parent);

	fib_attached_export_import(fib_entry,
				   fib_table_get_index_for_sw_if_index(
				       fib_entry_get_proto(fib_entry),
                                       sw_if_index));
    }
    else if (was_import && !is_import)
    {
	/*
	 * transition from exported to not exported
	 */
	fib_attached_export_purge(fib_entry);
    }
    /*
     * else
     *   no change. nothing to do.
     */

    /*
     * reload the entry address post possible pool realloc
     */
    fib_entry = fib_entry_get(fei);

    /*
     * handle changes to attached export for export entries
     */
    int is_attached  = (FIB_ENTRY_FLAG_ATTACHED & fib_entry_get_flags_i(fib_entry));
    int was_attached = (FIB_ENTRY_FLAG_ATTACHED & old_flags);

    if (!was_attached && is_attached)
    {
	/*
	 * transition to attached. time to export
	 */
	// FIXME
    }
    // else FIXME

    return (fib_entry);
}

static fib_entry_t*
fib_entry_post_install_actions (fib_entry_t *fib_entry,
				fib_source_t source,
				fib_entry_flag_t old_flags)
{
    fib_entry = fib_entry_post_flag_update_actions(fib_entry,
                                                   old_flags);
    fib_entry = fib_entry_src_action_installed(fib_entry, source);

    return (fib_entry);
}

fib_node_index_t
fib_entry_create (u32 fib_index,
		  const fib_prefix_t *prefix,
		  fib_source_t source,
		  fib_entry_flag_t flags,
		  const fib_route_path_t *paths)
{
    fib_node_index_t fib_entry_index;
    fib_entry_t *fib_entry;

    ASSERT(0 < vec_len(paths));

    fib_entry = fib_entry_alloc(fib_index, prefix, &fib_entry_index);

    /*
     * since this is a new entry create, we don't need to check for winning
     * sources - there is only one.
     */
    fib_entry = fib_entry_src_action_add(fib_entry, source, flags,
                                         drop_dpo_get(
                                             fib_proto_to_dpo(
                                                 fib_entry_get_proto(fib_entry))));
    fib_entry_src_action_path_swap(fib_entry,
				   source,
				   flags,
				   paths);
    /*
     * handle possible realloc's by refetching the pointer
     */
    fib_entry = fib_entry_get(fib_entry_index);
    fib_entry_src_action_activate(fib_entry, source);

    fib_entry = fib_entry_post_install_actions(fib_entry, source,
                                               FIB_ENTRY_FLAG_NONE);

    FIB_ENTRY_DBG(fib_entry, "create");

    return (fib_entry_index);
}

fib_node_index_t
fib_entry_create_special (u32 fib_index,
			  const fib_prefix_t *prefix,
			  fib_source_t source,
			  fib_entry_flag_t flags,
			  const dpo_id_t *dpo)
{
    fib_node_index_t fib_entry_index;
    fib_entry_t *fib_entry;

    /*
     * create and initialize the new enty
     */
    fib_entry = fib_entry_alloc(fib_index, prefix, &fib_entry_index);

    /*
     * create the path-list
     */
    fib_entry = fib_entry_src_action_add(fib_entry, source, flags, dpo);
    fib_entry_src_action_activate(fib_entry, source);

    fib_entry = fib_entry_post_install_actions(fib_entry, source,
                                               FIB_ENTRY_FLAG_NONE);

    FIB_ENTRY_DBG(fib_entry, "create-special");

    return (fib_entry_index);
}

static void
fib_entry_post_update_actions (fib_entry_t *fib_entry,
			       fib_source_t source,
			       fib_entry_flag_t old_flags)
{
    /*
     * backwalk to children to inform then of the change to forwarding.
     */
    fib_node_back_walk_ctx_t bw_ctx = {
	.fnbw_reason = FIB_NODE_BW_REASON_FLAG_EVALUATE,
    };

    fib_walk_sync(FIB_NODE_TYPE_ENTRY, fib_entry_get_index(fib_entry), &bw_ctx);

    /*
     * then inform any covered prefixes
     */
    fib_entry_cover_update_notify(fib_entry);

    fib_entry_post_install_actions(fib_entry, source, old_flags);
}

void
fib_entry_recalculate_forwarding (fib_node_index_t fib_entry_index)
{
    fib_source_t best_source;
    fib_entry_t *fib_entry;
    fib_entry_src_t *bsrc;

    fib_entry = fib_entry_get(fib_entry_index);

    bsrc = fib_entry_get_best_src_i(fib_entry);
    best_source = fib_entry_src_get_source(bsrc);

    fib_entry_src_action_reactivate(fib_entry, best_source);
}

static void
fib_entry_source_change_w_flags (fib_entry_t *fib_entry,
                                 fib_source_t old_source,
                                 fib_entry_flag_t old_flags,
                                 fib_source_t new_source)
{
    switch (fib_source_cmp(new_source, old_source))
    {
    case FIB_SOURCE_CMP_BETTER:
	/*
	 * we have a new winning source.
	 */
	fib_entry_src_action_deactivate(fib_entry, old_source);
	fib_entry_src_action_activate(fib_entry, new_source);
        break;

    case FIB_SOURCE_CMP_WORSE:
        /*
         * the new source loses. Re-activate the winning sources
         * in case it is an interposer and hence relied on the losing
         * source's path-list.
         */
        fib_entry_src_action_reactivate(fib_entry, old_source);
        return;

    case FIB_SOURCE_CMP_EQUAL:
	/*
	 * the new source is one this entry already has.
	 * But the path-list was updated, which will contribute new forwarding,
	 * so install it.
	 */
        fib_entry_src_action_reactivate(fib_entry, new_source);
        break;
    }

    fib_entry_post_update_actions(fib_entry, new_source, old_flags);
}

void
fib_entry_source_change (fib_entry_t *fib_entry,
                         fib_source_t old_source,
			 fib_source_t new_source)
{
    fib_entry_flag_t old_flags;

    old_flags = fib_entry_get_flags_for_source(
        fib_entry_get_index(fib_entry), old_source);

    return (fib_entry_source_change_w_flags(fib_entry, old_source,
                                            old_flags, new_source));
}

void
fib_entry_special_add (fib_node_index_t fib_entry_index,
		       fib_source_t source,
		       fib_entry_flag_t flags,
		       const dpo_id_t *dpo)
{
    fib_source_t best_source;
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);
    best_source = fib_entry_get_best_source(fib_entry_index);

    fib_entry = fib_entry_src_action_add(fib_entry, source, flags, dpo);
    fib_entry_source_change(fib_entry, best_source, source);
    FIB_ENTRY_DBG(fib_entry, "special-add:%U", format_fib_source, source);
}

void
fib_entry_special_update (fib_node_index_t fib_entry_index,
			  fib_source_t source,
			  fib_entry_flag_t flags,
			  const dpo_id_t *dpo)
{
    fib_source_t best_source;
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);
    best_source = fib_entry_get_best_source(fib_entry_index);

    fib_entry = fib_entry_src_action_update(fib_entry, source, flags, dpo);
    fib_entry_source_change(fib_entry, best_source, source);

    FIB_ENTRY_DBG(fib_entry, "special-updated:%U", format_fib_source, source);
}


void
fib_entry_path_add (fib_node_index_t fib_entry_index,
		    fib_source_t source,
		    fib_entry_flag_t flags,
		    const fib_route_path_t *rpaths)
{
    fib_source_t best_source;
    fib_entry_t *fib_entry;
    fib_entry_src_t *bsrc;

    fib_entry = fib_entry_get(fib_entry_index);
    ASSERT(NULL != fib_entry);

    bsrc = fib_entry_get_best_src_i(fib_entry);
    best_source = fib_entry_src_get_source(bsrc);
    
    fib_entry = fib_entry_src_action_path_add(fib_entry, source, flags, rpaths);

    fib_entry_source_change(fib_entry, best_source, source);

    FIB_ENTRY_DBG(fib_entry, "path add:%U", format_fib_source, source);
}

static fib_entry_src_flag_t
fib_entry_src_burn_only_inherited (fib_entry_t *fib_entry)
{
    fib_entry_src_t *src;
    fib_source_t source;
    int has_only_inherited_sources = 1;

    FOR_EACH_SRC_ADDED(fib_entry, src, source,
    ({
        if (!(src->fes_flags & FIB_ENTRY_SRC_FLAG_INHERITED))
        {
            has_only_inherited_sources = 0;
            break;
        }
    }));
    if (has_only_inherited_sources)
    {
        FOR_EACH_SRC_ADDED(fib_entry, src, source,
        ({
            fib_entry_src_action_remove(fib_entry, source);
        }));
        return (FIB_ENTRY_SRC_FLAG_NONE);
    }
    else
    {
        return (FIB_ENTRY_SRC_FLAG_ADDED);
    }
}

static fib_entry_src_flag_t
fib_entry_source_removed (fib_entry_t *fib_entry,
                          fib_entry_flag_t old_flags)
{
    const fib_entry_src_t *bsrc;
    fib_source_t best_source;

    /*
     * if all that is left are inherited sources, then burn them
     */
    fib_entry_src_burn_only_inherited(fib_entry);

    bsrc = fib_entry_get_best_src_i(fib_entry);
    best_source = fib_entry_src_get_source(bsrc);

    if (FIB_SOURCE_INVALID == best_source)
    {
        /*
         * no more sources left. this entry is toast.
         */
        fib_entry = fib_entry_post_flag_update_actions(fib_entry, old_flags);
        fib_entry_src_action_uninstall(fib_entry);

        return (FIB_ENTRY_SRC_FLAG_NONE);
    }
    else
    {
        fib_entry_src_action_activate(fib_entry, best_source);
    }

    fib_entry_post_update_actions(fib_entry, best_source, old_flags);

    /*
     * still have sources
     */
    return (FIB_ENTRY_SRC_FLAG_ADDED);
}

/*
 * fib_entry_path_remove
 *
 * remove a path from the entry.
 * return the fib_entry's index if it is still present, INVALID otherwise.
 */
fib_entry_src_flag_t
fib_entry_path_remove (fib_node_index_t fib_entry_index,
		       fib_source_t source,
		       const fib_route_path_t *rpaths)
{
    fib_entry_src_flag_t sflag;
    fib_source_t best_source;
    fib_entry_flag_t bflags;
    fib_entry_t *fib_entry;
    fib_entry_src_t *bsrc;

    fib_entry = fib_entry_get(fib_entry_index);
    ASSERT(NULL != fib_entry);

    bsrc = fib_entry_get_best_src_i(fib_entry);
    best_source = fib_entry_src_get_source(bsrc);
    bflags = fib_entry_src_get_flags(bsrc);

    sflag = fib_entry_src_action_path_remove(fib_entry, source, rpaths);

    FIB_ENTRY_DBG(fib_entry, "path remove:%U", format_fib_source, source);

    /*
     * if the path list for the source passed is invalid,
     * then we need to create a new one. else we are updating
     * an existing.
     */
    switch (fib_source_cmp(source, best_source))
    {
    case FIB_SOURCE_CMP_BETTER:
	/*
	 * Que! removing a path from a source that is better than the
	 * one this entry is using.
	 */
	ASSERT(0);
        break;
    case FIB_SOURCE_CMP_WORSE:
	/*
	 * the source is not the best. no need to update forwarding
	 */
	if (FIB_ENTRY_SRC_FLAG_ADDED & sflag)
        {
            /*
             * the source being removed still has paths
             */
            return (FIB_ENTRY_SRC_FLAG_ADDED);
        }
        else
        {
            /*
             * that was the last path from this source, check if those
             * that remain are non-inherited
             */
            return (fib_entry_src_burn_only_inherited(fib_entry));
        }
        break;
    case FIB_SOURCE_CMP_EQUAL:
	/*
	 * removing a path from the path-list we were using.
	 */
	if (!(FIB_ENTRY_SRC_FLAG_ADDED & sflag))
	{
	    /*
	     * the last path from the source was removed.
	     * fallback to lower source
	     */
            return (fib_entry_source_removed(fib_entry, bflags));
	}
	else
	{
	    /*
	     * re-install the new forwarding information
	     */
	    fib_entry_src_action_reactivate(fib_entry, source);
	}
        break;
    }

    fib_entry_post_update_actions(fib_entry, source, bflags);

    /*
     * still have sources
     */
    return (FIB_ENTRY_SRC_FLAG_ADDED);
}

/*
 * fib_entry_special_remove
 *
 * remove a special source from the entry.
 * return the fib_entry's index if it is still present, INVALID otherwise.
 */
fib_entry_src_flag_t
fib_entry_special_remove (fib_node_index_t fib_entry_index,
			  fib_source_t source)
{
    fib_entry_src_flag_t sflag;
    fib_source_t best_source;
    fib_entry_flag_t bflags;
    fib_entry_t *fib_entry;
    fib_entry_src_t *bsrc;

    fib_entry = fib_entry_get(fib_entry_index);
    ASSERT(NULL != fib_entry);

    bsrc = fib_entry_get_best_src_i(fib_entry);
    best_source = fib_entry_src_get_source(bsrc);
    bflags = fib_entry_src_get_flags(bsrc);

    FIB_ENTRY_DBG(fib_entry, "special remove:%U", format_fib_source, source);

    sflag = fib_entry_src_action_remove_or_update_inherit(fib_entry, source);

    /*
     * if the path list for the source passed is invalid,
     * then we need to create a new one. else we are updating
     * an existing.
     */
    switch (fib_source_cmp(source, best_source))
    {
    case FIB_SOURCE_CMP_BETTER:
	/*
	 * Que! removing a path from a source that is better than the
	 * one this entry is using. This can only mean it is a source
         * this prefix does not have.
	 */
        return (FIB_ENTRY_SRC_FLAG_ADDED);

    case FIB_SOURCE_CMP_WORSE:
	/*
	 * the source is not the best. no need to update forwarding
	 */
	if (FIB_ENTRY_SRC_FLAG_ADDED & sflag)
        {
            /*
             * the source being removed still has paths
             */
            return (FIB_ENTRY_SRC_FLAG_ADDED);
        }
        else
        {
            /*
             * that was the last path from this source, check if those
             * that remain are non-inherited
             */
            if (FIB_ENTRY_SRC_FLAG_NONE == fib_entry_src_burn_only_inherited(fib_entry))
            {
                /*
                 * no more sources left. this entry is toast.
                 */
                fib_entry = fib_entry_post_flag_update_actions(fib_entry, bflags);
                fib_entry_src_action_uninstall(fib_entry);
                return (FIB_ENTRY_SRC_FLAG_NONE);
            }

            /*
             * reactivate the best source so the interposer gets restacked
             */
            fib_entry_src_action_reactivate(fib_entry, best_source);

            return (FIB_ENTRY_SRC_FLAG_ADDED);
        }
        break;

    case FIB_SOURCE_CMP_EQUAL:
	if (!(FIB_ENTRY_SRC_FLAG_ADDED & sflag))
	{
	    /*
	     * the source was removed. use the next best.
	     */
            return (fib_entry_source_removed(fib_entry, bflags));
	}
	else
	{
	    /*
	     * re-install the new forwarding information
	     */
	    fib_entry_src_action_reactivate(fib_entry, source);
	}
        break;
    }

    fib_entry_post_update_actions(fib_entry, source, bflags);

    /*
     * still have sources
     */
    return (FIB_ENTRY_SRC_FLAG_ADDED);
}

/**
 * fib_entry_inherit
 *
 * If the source on the cover is inheriting then push this source
 * down to the covered.
 */
void
fib_entry_inherit (fib_node_index_t cover,
                   fib_node_index_t covered)
{
    fib_entry_src_inherit(fib_entry_get(cover),
                          fib_entry_get(covered));
}

/**
 * fib_entry_delete
 *
 * The source is withdrawing all the paths it provided
 */
fib_entry_src_flag_t
fib_entry_delete (fib_node_index_t fib_entry_index,
		  fib_source_t source)
{
    return (fib_entry_special_remove(fib_entry_index, source));
}

/**
 * fib_entry_update
 *
 * The source has provided a new set of paths that will replace the old.
 */
void
fib_entry_update (fib_node_index_t fib_entry_index,
		  fib_source_t source,
		  fib_entry_flag_t flags,
		  const fib_route_path_t *paths)
{
    fib_source_t best_source;
    fib_entry_flag_t bflags;
    fib_entry_t *fib_entry;
    fib_entry_src_t *bsrc;

    fib_entry = fib_entry_get(fib_entry_index);
    ASSERT(NULL != fib_entry);

    bsrc = fib_entry_get_best_src_i(fib_entry);
    best_source = fib_entry_src_get_source(bsrc);
    bflags = fib_entry_get_flags_i(fib_entry);

    fib_entry = fib_entry_src_action_path_swap(fib_entry,
                                               source,
                                               flags,
                                               paths);

    fib_entry_source_change_w_flags(fib_entry, best_source, bflags, source);
    FIB_ENTRY_DBG(fib_entry, "update");
}


/*
 * fib_entry_cover_changed
 *
 * this entry is tracking its cover and that cover has changed.
 */
void
fib_entry_cover_changed (fib_node_index_t fib_entry_index)
{
    fib_entry_src_cover_res_t res = {
	.install = !0,
	.bw_reason = FIB_NODE_BW_REASON_FLAG_NONE,
    };
    CLIB_UNUSED(fib_source_t source);
    fib_source_t best_source;
    fib_entry_flag_t bflags;
    fib_entry_t *fib_entry;
    fib_entry_src_t *esrc;
    u32 index;

    bflags = FIB_ENTRY_FLAG_NONE;
    best_source = FIB_SOURCE_FIRST;
    fib_entry = fib_entry_get(fib_entry_index);

    fib_attached_export_cover_change(fib_entry);

    /*
     * propagate the notification to each of the added sources
     */
    index = 0;
    FOR_EACH_SRC_ADDED(fib_entry, esrc, source,
    ({
	if (0 == index)
	{
	    /*
	     * only the best source gets to set the back walk flags
	     */
	    res = fib_entry_src_action_cover_change(fib_entry, esrc);
            bflags = fib_entry_src_get_flags(esrc);
            best_source = fib_entry_src_get_source(esrc);
	}
	else
	{
	    fib_entry_src_action_cover_change(fib_entry, esrc);
	}
	index++;
    }));

    if (res.install)
    {
	fib_entry_src_action_reactivate(fib_entry,
					fib_entry_src_get_source(
					    fib_entry_get_best_src_i(fib_entry)));
        fib_entry = fib_entry_post_install_actions(fib_entry,
                                                   best_source,
                                                   bflags);
    }
    else
    {
	fib_entry_src_action_uninstall(fib_entry);
    }

    if (FIB_NODE_BW_REASON_FLAG_NONE != res.bw_reason)
    {
	/*
	 * time for walkies fido.
	 */
	fib_node_back_walk_ctx_t bw_ctx = {
	    .fnbw_reason = res.bw_reason,
        };

	fib_walk_sync(FIB_NODE_TYPE_ENTRY, fib_entry_index, &bw_ctx);
    }
    FIB_ENTRY_DBG(fib_entry, "cover-changed");
}

/*
 * fib_entry_cover_updated
 *
 * this entry is tracking its cover and that cover has been updated
 * (i.e. its forwarding information has changed).
 */
void
fib_entry_cover_updated (fib_node_index_t fib_entry_index)
{
    fib_entry_src_cover_res_t res = {
	.install = !0,
	.bw_reason = FIB_NODE_BW_REASON_FLAG_NONE,
    };
    CLIB_UNUSED(fib_source_t source);
    fib_source_t best_source;
    fib_entry_flag_t bflags;
    fib_entry_t *fib_entry;
    fib_entry_src_t *esrc;
    u32 index;

    bflags = FIB_ENTRY_FLAG_NONE;
    best_source = FIB_SOURCE_FIRST;
    fib_entry = fib_entry_get(fib_entry_index);

    fib_attached_export_cover_update(fib_entry);

    /*
     * propagate the notification to each of the added sources
     */
    index = 0;
    FOR_EACH_SRC_ADDED(fib_entry, esrc, source,
    ({
	if (0 == index)
	{
	    /*
	     * only the best source gets to set the install result
	     */
	    res = fib_entry_src_action_cover_update(fib_entry, esrc);
            bflags = fib_entry_src_get_flags(esrc);
            best_source = fib_entry_src_get_source(esrc);
	}
	else
	{
	    /*
	     * contirubting sources can set backwalk flags
	     */
            if (esrc->fes_flags & FIB_ENTRY_SRC_FLAG_CONTRIBUTING)
            {
                fib_entry_src_cover_res_t tmp = {
                    .install = !0,
                    .bw_reason = FIB_NODE_BW_REASON_FLAG_NONE,
                };

                tmp = fib_entry_src_action_cover_update(fib_entry, esrc);
                res.bw_reason |= tmp.bw_reason;
            }
            else
            {
                fib_entry_src_action_cover_update(fib_entry, esrc);
            }
	}
	index++;
    }));

    if (res.install)
    {
	fib_entry_src_action_reactivate(fib_entry,
					fib_entry_src_get_source(
					    fib_entry_get_best_src_i(fib_entry)));
        fib_entry = fib_entry_post_install_actions(fib_entry,
                                                   best_source,
                                                   bflags);
    }
    else
    {
	fib_entry_src_action_uninstall(fib_entry);
    }

    if (FIB_NODE_BW_REASON_FLAG_NONE != res.bw_reason)
    {
	/*
	 * time for walkies fido.
	 */
	fib_node_back_walk_ctx_t bw_ctx = {
	    .fnbw_reason = res.bw_reason,
        };

	fib_walk_sync(FIB_NODE_TYPE_ENTRY, fib_entry_index, &bw_ctx);
    }
    FIB_ENTRY_DBG(fib_entry, "cover-updated");
}

int
fib_entry_recursive_loop_detect (fib_node_index_t entry_index,
				 fib_node_index_t **entry_indicies)
{
    fib_entry_t *fib_entry;
    int was_looped, is_looped;

    fib_entry = fib_entry_get(entry_index);

    if (FIB_NODE_INDEX_INVALID != fib_entry->fe_parent)
    {
	fib_node_index_t *entries = *entry_indicies;

	vec_add1(entries, entry_index);
	was_looped = fib_path_list_is_looped(fib_entry->fe_parent);
	is_looped = fib_path_list_recursive_loop_detect(fib_entry->fe_parent,
							&entries);

	*entry_indicies = entries;

	if (!!was_looped != !!is_looped)
	{
	    /*
	     * re-evaluate all the entry's forwarding
	     * NOTE: this is an inplace modify
	     */
            fib_entry_delegate_type_t fdt;
            fib_entry_delegate_t *fed;

            FOR_EACH_DELEGATE_CHAIN(fib_entry, fdt, fed,
            {
                fib_entry_src_mk_lb(fib_entry,
                                    fib_entry_get_best_source(entry_index),
                                    fib_entry_delegate_type_to_chain_type(fdt),
                                    &fed->fd_dpo);
	    });
	}
    }
    else
    {
	/*
	 * the entry is currently not linked to a path-list. this happens
	 * when it is this entry that is re-linking path-lists and has thus
	 * broken the loop
	 */
	is_looped = 0;
    }

    return (is_looped);
}

u32
fib_entry_get_resolving_interface (fib_node_index_t entry_index)
{
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(entry_index);

    return (fib_path_list_get_resolving_interface(fib_entry->fe_parent));
}

u32
fib_entry_get_any_resolving_interface (fib_node_index_t entry_index)
{
    const fib_entry_src_t *src;
    fib_entry_t *fib_entry;
    fib_source_t source;
    u32 sw_if_index;

    fib_entry = fib_entry_get(entry_index);

    FOR_EACH_SRC_ADDED(fib_entry, src, source,
    ({
        sw_if_index = fib_entry_get_resolving_interface_for_source (entry_index,
                                                                    source);

        if (~0 != sw_if_index)
            break;
    }));
    return (sw_if_index);
}

fib_source_t
fib_entry_get_best_source (fib_node_index_t entry_index)
{
    fib_entry_t *fib_entry;
    fib_entry_src_t *bsrc;

    fib_entry = fib_entry_get(entry_index);

    bsrc = fib_entry_get_best_src_i(fib_entry);
    return (fib_entry_src_get_source(bsrc));
}

/**
 * Return !0 is the entry represents a host prefix
 */
int
fib_entry_is_host (fib_node_index_t fib_entry_index)
{
    return (fib_prefix_is_host(fib_entry_get_prefix(fib_entry_index)));
}

/**
 * Return !0 is the entry is resolved, i.e. will return a valid forwarding
 * chain
 */
int
fib_entry_is_resolved (fib_node_index_t fib_entry_index)
{
    fib_entry_delegate_t *fed;
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);

    fed = fib_entry_delegate_find(fib_entry, FIB_ENTRY_DELEGATE_BFD);

    if (NULL == fed)
    {
        /*
         * no BFD tracking - consider it resolved.
         */
        return (!0);
    }
    else
    {
        /*
         * defer to the state of the BFD tracking
         */
        return (FIB_BFD_STATE_UP == fed->fd_bfd_state);
    }
}

void
fib_entry_set_flow_hash_config (fib_node_index_t fib_entry_index,
                                flow_hash_config_t hash_config)
{
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);

    /*
     * pass the hash-config on to the load-balance object where it is cached.
     * we can ignore LBs in the delegate chains, since they will not be of the
     * correct protocol type (i.e. they are not IP)
     * There's no way, nor need, to change the hash config for MPLS.
     */
    if (dpo_id_is_valid(&fib_entry->fe_lb))
    {
        load_balance_t *lb;

        ASSERT(DPO_LOAD_BALANCE == fib_entry->fe_lb.dpoi_type);

        lb = load_balance_get(fib_entry->fe_lb.dpoi_index);

        /*
         * atomic update for packets in flight
         */
        lb->lb_hash_config = hash_config;
    }
}

u32
fib_entry_get_stats_index (fib_node_index_t fib_entry_index)
{
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);

    return (fib_entry->fe_lb.dpoi_index);
}

static int
fib_ip4_address_compare (const ip4_address_t * a1,
                         const ip4_address_t * a2)
{
    /*
     * IP addresses are unsigned ints. the return value here needs to be signed
     * a simple subtraction won't cut it.
     * If the addresses are the same, the sort order is undefined, so phoey.
     */
    return ((clib_net_to_host_u32(a1->data_u32) >
	     clib_net_to_host_u32(a2->data_u32) ) ?
	    1 : -1);
}

static int
fib_ip6_address_compare (const ip6_address_t * a1,
                         const ip6_address_t * a2)
{
  int i;
  for (i = 0; i < ARRAY_LEN (a1->as_u16); i++)
  {
      int cmp = (clib_net_to_host_u16 (a1->as_u16[i]) -
		 clib_net_to_host_u16 (a2->as_u16[i]));
      if (cmp != 0)
	  return cmp;
  }
  return 0;
}

static int
fib_entry_cmp (fib_node_index_t fib_entry_index1,
	       fib_node_index_t fib_entry_index2)
{
    fib_entry_t *fib_entry1, *fib_entry2;
    int cmp = 0;

    fib_entry1 = fib_entry_get(fib_entry_index1);
    fib_entry2 = fib_entry_get(fib_entry_index2);

    switch (fib_entry1->fe_prefix.fp_proto)
    {
    case FIB_PROTOCOL_IP4:
        cmp = fib_ip4_address_compare(&fib_entry1->fe_prefix.fp_addr.ip4,
                                      &fib_entry2->fe_prefix.fp_addr.ip4);
        break;
    case FIB_PROTOCOL_IP6:
        cmp = fib_ip6_address_compare(&fib_entry1->fe_prefix.fp_addr.ip6,
                                      &fib_entry2->fe_prefix.fp_addr.ip6);
        break;
    case FIB_PROTOCOL_MPLS:
	cmp = (fib_entry1->fe_prefix.fp_label - fib_entry2->fe_prefix.fp_label);

	if (0 == cmp)
	{
	    cmp = (fib_entry1->fe_prefix.fp_eos - fib_entry2->fe_prefix.fp_eos);
	}
        break;
    }

    if (0 == cmp) {
	cmp = (fib_entry1->fe_prefix.fp_len - fib_entry2->fe_prefix.fp_len);
    }
    return (cmp);   
}

int
fib_entry_cmp_for_sort (void *i1, void *i2)
{
    fib_node_index_t *fib_entry_index1 = i1, *fib_entry_index2 = i2;

    return (fib_entry_cmp(*fib_entry_index1,
			  *fib_entry_index2));
}

void
fib_entry_lock (fib_node_index_t fib_entry_index)
{
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);

    fib_node_lock(&fib_entry->fe_node);
}

void
fib_entry_unlock (fib_node_index_t fib_entry_index)
{
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);

    fib_node_unlock(&fib_entry->fe_node);
}

void
fib_entry_module_init (void)
{
    fib_node_register_type(FIB_NODE_TYPE_ENTRY, &fib_entry_vft);
    fib_entry_logger = vlib_log_register_class("fib", "entry");

    fib_entry_track_module_init();
}

fib_route_path_t *
fib_entry_encode (fib_node_index_t fib_entry_index)
{
    fib_path_ext_list_t *ext_list;
    fib_path_encode_ctx_t ctx = {
        .rpaths = NULL,
    };
    fib_entry_t *fib_entry;
    fib_entry_src_t *bsrc;

    ext_list = NULL;
    fib_entry = fib_entry_get(fib_entry_index);
    bsrc = fib_entry_get_best_src_i(fib_entry);

    if (bsrc)
    {
	ext_list = &bsrc->fes_path_exts;
    }

    if (FIB_NODE_INDEX_INVALID != fib_entry->fe_parent)
    {
        fib_path_list_walk_w_ext(fib_entry->fe_parent,
                                 ext_list,
                                 fib_path_encode,
                                 &ctx);
    }

    return (ctx.rpaths);
}

const fib_prefix_t *
fib_entry_get_prefix (fib_node_index_t fib_entry_index)
{
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);

    return (&fib_entry->fe_prefix);
}

u32
fib_entry_get_fib_index (fib_node_index_t fib_entry_index)
{
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);

    return (fib_entry->fe_fib_index);
}

u32
fib_entry_pool_size (void)
{
    return (pool_elts(fib_entry_pool));
}

#if CLIB_DEBUG > 0
void
fib_table_assert_empty (const fib_table_t *fib_table)
{
    fib_node_index_t *fei, *feis = NULL;
    fib_entry_t *fib_entry;

    pool_foreach (fib_entry, fib_entry_pool)
     {
        if (fib_entry->fe_fib_index == fib_table->ft_index)
            vec_add1 (feis, fib_entry_get_index(fib_entry));
    }

    if (vec_len(feis))
    {
        vec_foreach (fei, feis)
            clib_error ("%U", format_fib_entry, *fei, FIB_ENTRY_FORMAT_DETAIL);
    }

    ASSERT(0);
}
#endif

static clib_error_t *
show_fib_entry_command (vlib_main_t * vm,
			unformat_input_t * input,
			vlib_cli_command_t * cmd)
{
    fib_node_index_t fei;

    if (unformat (input, "%d", &fei))
    {
	/*
	 * show one in detail
	 */
	if (!pool_is_free_index(fib_entry_pool, fei))
	{
	    vlib_cli_output (vm, "%d@%U",
			     fei,
			     format_fib_entry, fei,
			     FIB_ENTRY_FORMAT_DETAIL2);
	}
	else
	{
	    vlib_cli_output (vm, "entry %d invalid", fei);
	}
    }
    else
    {
	/*
	 * show all
	 */
	vlib_cli_output (vm, "FIB Entries:");
	pool_foreach_index (fei, fib_entry_pool)
         {
	    vlib_cli_output (vm, "%d@%U",
			     fei,
			     format_fib_entry, fei,
			     FIB_ENTRY_FORMAT_BRIEF);
	}
    }

    return (NULL);
}

VLIB_CLI_COMMAND (show_fib_entry, static) = {
  .path = "show fib entry",
  .function = show_fib_entry_command,
  .short_help = "show fib entry",
};