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path: root/src/vnet/mfib/mfib_entry.c
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import socket
import unittest

from util import ppp
from framework import VppTestRunner
from template_ipsec import IPSecIPv4Fwd

"""
When an IPSec SPD is configured on an interface, any inbound packets
not matching inbound policies, or outbound packets not matching outbound
policies, must be dropped by default as per RFC4301.

This test uses simple IPv4 forwarding on interfaces with IPSec enabled
to check if packets with no matching rules are dropped by default.

The basic setup is a single SPD bound to two interfaces, pg0 and pg1.

                    ┌────┐        ┌────┐
                    │SPD1│        │SPD1│
                    ├────┤ ─────> ├────┤
                    │PG0 │        │PG1 │
                    └────┘        └────┘

First, both inbound and outbound BYPASS policies are configured allowing
traffic to pass from pg0 -> pg1.

Packets are captured and verified at pg1.

Then either the inbound or outbound policies are removed and we verify
packets are dropped as expected.

"""


class IPSecInboundDefaultDrop(IPSecIPv4Fwd):
    """IPSec: inbound packets drop by default with no matching rule"""

    def test_ipsec_inbound_default_drop(self):
        # configure two interfaces and bind the same SPD to both
        self.create_interfaces(2)
        self.spd_create_and_intf_add(1, self.pg_interfaces)
        pkt_count = 5

        # catch-all inbound BYPASS policy, all interfaces
        inbound_policy = self.spd_add_rem_policy(
            1,
            None,
            None,
            socket.IPPROTO_UDP,
            is_out=0,
            priority=10,
            policy_type="bypass",
            all_ips=True,
        )

        # outbound BYPASS policy allowing traffic from pg0->pg1
        outbound_policy = self.spd_add_rem_policy(
            1,
            self.pg0,
            self.pg1,
            socket.IPPROTO_UDP,
            is_out=1,
            priority=10,
            policy_type="bypass",
        )

        # create a packet stream pg0->pg1 + add to pg0
        packets0 = self.create_stream(self.pg0, self.pg1, pkt_count)
        self.pg0.add_stream(packets0)

        # with inbound BYPASS rule at pg0, we expect to see forwarded
        # packets on pg1
        self.pg_interfaces[1].enable_capture()
        self.pg_start()
        cap1 = self.pg1.get_capture()
        for packet in cap1:
            try:
                self.logger.debug(ppp("SPD - Got packet:", packet))
            except Exception:
                self.logger.error(ppp("Unexpected or invalid packet:", packet))
                raise
        self.logger.debug("SPD: Num packets: %s", len(cap1.res))
        # verify captures on pg1
        self.verify_capture(self.pg0, self.pg1, cap1)
        # verify policies matched correct number of times
        self.verify_policy_match(pkt_count, inbound_policy)
        self.verify_policy_match(pkt_count, outbound_policy)

        # remove inbound catch-all BYPASS rule, traffic should now be dropped
        self.spd_add_rem_policy(  # inbound, all interfaces
            1,
            None,
            None,
            socket.IPPROTO_UDP,
            is_out=0,
            priority=10,
            policy_type="bypass",
            all_ips=True,
            remove=True,
        )

        # create another packet stream pg0->pg1 + add to pg0
        packets1 = self.create_stream(self.pg0, self.pg1, pkt_count)
        self.pg0.add_stream(packets1)
        self.pg_interfaces[1].enable_capture()
        self.pg_start()
        # confirm traffic has now been dropped
        self.pg1.assert_nothing_captured(
            remark="inbound pkts with no matching" "rules NOT dropped by default"
        )
        # both policies should not have matched any further packets
        # since we've dropped at input stage
        self.verify_policy_match(pkt_count, outbound_policy)
        self.verify_policy_match(pkt_count, inbound_policy)


class IPSecOutboundDefaultDrop(IPSecIPv4Fwd):
    """IPSec: outbound packets drop by default with no matching rule"""

    def test_ipsec_inbound_default_drop(self):
        # configure two interfaces and bind the same SPD to both
        self.create_interfaces(2)
        self.spd_create_and_intf_add(1, self.pg_interfaces)
        pkt_count = 5

        # catch-all inbound BYPASS policy, all interfaces
        inbound_policy = self.spd_add_rem_policy(
            1,
            None,
            None,
            socket.IPPROTO_UDP,
            is_out=0,
            priority=10,
            policy_type="bypass",
            all_ips=True,
        )

        # outbound BYPASS policy allowing traffic from pg0->pg1
        outbound_policy = self.spd_add_rem_policy(
            1,
            self.pg0,
            self.pg1,
            socket.IPPROTO_UDP,
            is_out=1,
            priority=10,
            policy_type="bypass",
        )

        # create a packet stream pg0->pg1 + add to pg0
        packets0 = self.create_stream(self.pg0, self.pg1, pkt_count)
        self.pg0.add_stream(packets0)

        # with outbound BYPASS rule allowing pg0->pg1, we expect to see
        # forwarded packets on pg1
        self.pg_interfaces[1].enable_capture()
        self.pg_start()
        cap1 = self.pg1.get_capture()
        for packet in cap1:
            try:
                self.logger.debug(ppp("SPD - Got packet:", packet))
            except Exception:
                self.logger.error(ppp("Unexpected or invalid packet:", packet))
                raise
        self.logger.debug("SPD: Num packets: %s", len(cap1.res))
        # verify captures on pg1
        self.verify_capture(self.pg0, self.pg1, cap1)
        # verify policies matched correct number of times
        self.verify_policy_match(pkt_count, inbound_policy)
        self.verify_policy_match(pkt_count, outbound_policy)

        # remove outbound rule
        self.spd_add_rem_policy(
            1,
            self.pg0,
            self.pg1,
            socket.IPPROTO_UDP,
            is_out=1,
            priority=10,
            policy_type="bypass",
            remove=True,
        )

        # create another packet stream pg0->pg1 + add to pg0
        packets1 = self.create_stream(self.pg0, self.pg1, pkt_count)
        self.pg0.add_stream(packets1)
        self.pg_interfaces[1].enable_capture()
        self.pg_start()
        # confirm traffic was dropped and not forwarded
        self.pg1.assert_nothing_captured(
            remark="outbound pkts with no matching rules NOT dropped " "by default"
        )
        # inbound rule should have matched twice the # of pkts now
        self.verify_policy_match(pkt_count * 2, inbound_policy)
        # as dropped at outbound, outbound policy is the same
        self.verify_policy_match(pkt_count, outbound_policy)


if __name__ == "__main__":
    unittest.main(testRunner=VppTestRunner)
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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/mfib/mfib_entry.h>
#include <vnet/fib/fib_path_list.h>

#include <vnet/dpo/drop_dpo.h>
#include <vnet/dpo/replicate_dpo.h>

/**
 * Debug macro
 */
#ifdef MFIB_DEBUG
#DEFIne MFIB_ENTRY_DBG(_e, _fmt, _args...)		\
{                                                       \
    u8*__tmp = NULL;					\
    __tmp = format(__tmp, "e:[%d:%U",                   \
                   mfib_entry_get_index(_e),		\
                   format_ip46_address,			\
                   &_e->mfe_prefix.fp_grp_addr,		\
                   IP46_TYPE_ANY);			\
    __tmp = format(__tmp, "/%d,",			\
                   _e->mfe_prefix.fp_len);		\
    __tmp = format(__tmp, "%U]",                        \
                   mfib_entry_get_index(_e),		\
                   format_ip46_address,			\
                   &_e->mfe_prefix.fp_src_addr,		\
                   IP46_TYPE_ANY);			\
    __tmp = format(__tmp, _fmt, ##_args);		\
    clib_warning("%s", __tmp);				\
    vec_free(__tmp);					\
}
#else
#define MFIB_ENTRY_DBG(_e, _fmt, _args...)
#endif

/**
 * MFIB extensions to each path
 */
typedef struct mfib_path_ext_t_
{
    mfib_itf_flags_t mfpe_flags;
    fib_node_index_t mfpe_path;
} mfib_path_ext_t;

/**
 * The source of an MFIB entry
 */
typedef struct mfib_entry_src_t_
{
    /**
     * Which source this is
     */
    mfib_source_t mfes_src;

    /**
     * Route flags
     */
    mfib_entry_flags_t mfes_flags;

    /**
     * The path-list of forwarding interfaces
     */
    fib_node_index_t mfes_pl;

    /**
     * RPF-ID
     */
    fib_rpf_id_t mfes_rpf_id;

    /**
     * Hash table of path extensions
     */
    mfib_path_ext_t *mfes_exts;

    /**
     * The hash table of all interfaces.
     *  This is forwarding time information derived from the paths
     *  and their extensions.
     */
    mfib_itf_t *mfes_itfs;
} mfib_entry_src_t;

/**
 * Pool of path extensions
 */
static mfib_path_ext_t *mfib_path_ext_pool;

/**
 * String names for each source
 */
static const char *mfib_source_names[] = MFIB_SOURCE_NAMES;

/*
 * Pool for all fib_entries
 */
mfib_entry_t *mfib_entry_pool;

static fib_node_t *
mfib_entry_get_node (fib_node_index_t index)
{
    return ((fib_node_t*)mfib_entry_get(index));
}

static fib_protocol_t
mfib_entry_get_proto (const mfib_entry_t * mfib_entry)
{
    return (mfib_entry->mfe_prefix.fp_proto);
}

fib_forward_chain_type_t
mfib_entry_get_default_chain_type (const mfib_entry_t *mfib_entry)
{
    switch (mfib_entry->mfe_prefix.fp_proto)
    {
    case FIB_PROTOCOL_IP4:
        return (FIB_FORW_CHAIN_TYPE_MCAST_IP4);
    case FIB_PROTOCOL_IP6:
        return (FIB_FORW_CHAIN_TYPE_MCAST_IP6);
    case FIB_PROTOCOL_MPLS:
        ASSERT(0);
        break;
    }
    return (FIB_FORW_CHAIN_TYPE_MCAST_IP4);
}

static u8 *
format_mfib_entry_dpo (u8 * s, va_list * args)
{
    index_t fei = va_arg(*args, index_t);
    CLIB_UNUSED(u32 indent) = va_arg(*args, u32);

    return (format(s, "%U",
                   format_mfib_entry, fei,
                   MFIB_ENTRY_FORMAT_BRIEF));
}

static inline mfib_path_ext_t *
mfib_entry_path_ext_get (index_t mi)
{
    return (pool_elt_at_index(mfib_path_ext_pool, mi));
}

static u8 *
format_mfib_entry_path_ext (u8 * s, va_list * args)
{
    mfib_path_ext_t *path_ext;
    index_t mpi = va_arg(*args, index_t);

    path_ext = mfib_entry_path_ext_get(mpi);
    return (format(s, "path:%d flags:%U",
                   path_ext->mfpe_path,
                   format_mfib_itf_flags, path_ext->mfpe_flags));
}

u8 *
format_mfib_entry (u8 * s, va_list * args)
{
    fib_node_index_t fei, mfi;
    mfib_entry_t *mfib_entry;
    mfib_entry_src_t *msrc;
    u32 sw_if_index;
    int level;

    fei = va_arg (*args, fib_node_index_t);
    level = va_arg (*args, int);
    mfib_entry = mfib_entry_get(fei);

    s = format (s, "%U", format_mfib_prefix, &mfib_entry->mfe_prefix);
    s = format (s, ": %U", format_mfib_entry_flags, mfib_entry->mfe_flags);

    if (level >= MFIB_ENTRY_FORMAT_DETAIL)
    {
        fib_node_index_t path_index, mpi;

        s = format (s, "\n");
        s = format (s, " fib:%d", mfib_entry->mfe_fib_index);
        s = format (s, " index:%d", mfib_entry_get_index(mfib_entry));
        s = format (s, " locks:%d\n", mfib_entry->mfe_node.fn_locks);
        vec_foreach(msrc, mfib_entry->mfe_srcs)
        {
            s = format (s, "  src:%s", mfib_source_names[msrc->mfes_src]);
            s = format (s, ": %U\n", format_mfib_entry_flags, msrc->mfes_flags);
            if (FIB_NODE_INDEX_INVALID != msrc->mfes_pl)
            {
                s = fib_path_list_format(msrc->mfes_pl, s);
            }
            s = format (s, "    Extensions:\n");
            hash_foreach(path_index, mpi, msrc->mfes_exts,
            ({
                s = format(s, "     %U\n", format_mfib_entry_path_ext, mpi);
            }));
            s = format (s, "    Interface-Forwarding:\n");
            hash_foreach(sw_if_index, mfi, msrc->mfes_itfs,
            ({
                s = format(s, "    %U\n", format_mfib_itf, mfi);
            }));
        }
    }

    s = format(s, "\n  Interfaces:");
    hash_foreach(sw_if_index, mfi, mfib_entry->mfe_itfs,
    ({
        s = format(s, "\n  %U", format_mfib_itf, mfi);
    }));
    if (MFIB_RPF_ID_NONE != mfib_entry->mfe_rpf_id)
    {
        s = format(s, "\n  RPF-ID:%d", mfib_entry->mfe_rpf_id);
    }
    s = format(s, "\n  %U-chain\n  %U",
               format_fib_forw_chain_type,
               mfib_entry_get_default_chain_type(mfib_entry),
               format_dpo_id,
               &mfib_entry->mfe_rep,
               2);
    s = format(s, "\n");

    if (level >= MFIB_ENTRY_FORMAT_DETAIL2)
    {
        s = format(s, "\nchildren:");
        s = fib_node_children_format(mfib_entry->mfe_node.fn_children, s);
    }

    return (s);
}

static mfib_entry_t*
mfib_entry_from_fib_node (fib_node_t *node)
{
    ASSERT(FIB_NODE_TYPE_MFIB_ENTRY == node->fn_type);
    return ((mfib_entry_t*)node);
}

static int
mfib_entry_src_cmp_for_sort (void * v1,
                             void * v2)
{
    mfib_entry_src_t *esrc1 = v1, *esrc2 = v2;

    return (esrc1->mfes_src - esrc2->mfes_src);
}

static void
mfib_entry_src_init (mfib_entry_t *mfib_entry,
                     mfib_source_t source)

{
    mfib_entry_src_t esrc = {
        .mfes_pl = FIB_NODE_INDEX_INVALID,
        .mfes_flags = MFIB_ENTRY_FLAG_NONE,
        .mfes_src = source,
    };

    vec_add1(mfib_entry->mfe_srcs, esrc);
    vec_sort_with_function(mfib_entry->mfe_srcs,
                           mfib_entry_src_cmp_for_sort);
}

static mfib_entry_src_t *
mfib_entry_src_find (const mfib_entry_t *mfib_entry,
                    mfib_source_t source,
                    u32 *index)

{
    mfib_entry_src_t *esrc;
    int ii;

    ii = 0;
    vec_foreach(esrc, mfib_entry->mfe_srcs)
    {
        if (esrc->mfes_src == source)
        {
            if (NULL != index)
            {
                *index = ii;
            }
            return (esrc);
        }
        else
        {
            ii++;
        }
    }

    return (NULL);
}

static mfib_entry_src_t *
mfib_entry_src_find_or_create (mfib_entry_t *mfib_entry,
                               mfib_source_t source)
{
    mfib_entry_src_t *esrc;

    esrc = mfib_entry_src_find(mfib_entry, source, NULL);

    if (NULL == esrc)
    {
        mfib_entry_src_init(mfib_entry, source);
    }

    return (mfib_entry_src_find(mfib_entry, source, NULL));
}

static mfib_entry_src_t*
mfib_entry_get_best_src (const mfib_entry_t *mfib_entry)
{
    mfib_entry_src_t *bsrc;

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

    return (bsrc);
}

int
mfib_entry_is_sourced (fib_node_index_t mfib_entry_index,
                       mfib_source_t source)
{
    mfib_entry_t *mfib_entry;

    mfib_entry = mfib_entry_get(mfib_entry_index);

    return (NULL != mfib_entry_src_find(mfib_entry, source, NULL));
}

static void
mfib_entry_src_flush (mfib_entry_src_t *msrc)
{
    u32 sw_if_index;
    index_t mfii;

    hash_foreach(sw_if_index, mfii, msrc->mfes_itfs,
    ({
        mfib_itf_delete(mfib_itf_get(mfii));
    }));
    hash_free(msrc->mfes_itfs);
    msrc->mfes_itfs = NULL;
    fib_path_list_unlock(msrc->mfes_pl);
}

static void
mfib_entry_src_remove (mfib_entry_t *mfib_entry,
                       mfib_source_t source)

{
    mfib_entry_src_t *msrc;
    u32 index = ~0;

    msrc = mfib_entry_src_find(mfib_entry, source, &index);

    if (NULL != msrc)
    {
        mfib_entry_src_flush(msrc);
        vec_del1(mfib_entry->mfe_srcs, index);
    }
}

u32
mfib_entry_child_add (fib_node_index_t mfib_entry_index,
                      fib_node_type_t child_type,
                      fib_node_index_t child_index)
{
    return (fib_node_child_add(FIB_NODE_TYPE_MFIB_ENTRY,
                               mfib_entry_index,
                               child_type,
                               child_index));
};

void
mfib_entry_child_remove (fib_node_index_t mfib_entry_index,
                         u32 sibling_index)
{
    fib_node_child_remove(FIB_NODE_TYPE_MFIB_ENTRY,
                          mfib_entry_index,
                          sibling_index);
}

static mfib_entry_t *
mfib_entry_alloc (u32 fib_index,
                  const mfib_prefix_t *prefix,
                  fib_node_index_t *mfib_entry_index)
{
    mfib_entry_t *mfib_entry;

    pool_get_aligned(mfib_entry_pool, mfib_entry, CLIB_CACHE_LINE_BYTES);

    fib_node_init(&mfib_entry->mfe_node,
                  FIB_NODE_TYPE_MFIB_ENTRY);

    /*
     * Some of the members require non-default initialisation
     * so we also init those that don't and thus save on the call to memset.
     */
    mfib_entry->mfe_flags = 0;
    mfib_entry->mfe_fib_index = fib_index;
    mfib_entry->mfe_prefix = *prefix;
    mfib_entry->mfe_srcs = NULL;
    mfib_entry->mfe_itfs = NULL;
    mfib_entry->mfe_rpf_id = MFIB_RPF_ID_NONE;
    mfib_entry->mfe_pl = FIB_NODE_INDEX_INVALID;

    dpo_reset(&mfib_entry->mfe_rep);

    *mfib_entry_index = mfib_entry_get_index(mfib_entry);

    MFIB_ENTRY_DBG(mfib_entry, "alloc");

    return (mfib_entry);
}

static inline mfib_path_ext_t *
mfib_entry_path_ext_find (mfib_path_ext_t *exts,
                          fib_node_index_t path_index)
{
    uword *p;

    p = hash_get(exts, path_index);

    if (NULL != p)
    {
        return (mfib_entry_path_ext_get(p[0]));
    }

    return (NULL);
}

static mfib_path_ext_t*
mfib_path_ext_add (mfib_entry_src_t *msrc,
                   fib_node_index_t path_index,
                   mfib_itf_flags_t mfi_flags)
{
    mfib_path_ext_t *path_ext;

    pool_get(mfib_path_ext_pool, path_ext);

    path_ext->mfpe_flags = mfi_flags;
    path_ext->mfpe_path = path_index;

    hash_set(msrc->mfes_exts, path_index,
             path_ext - mfib_path_ext_pool);

    return (path_ext);
}

static void
mfib_path_ext_remove (mfib_entry_src_t *msrc,
                      fib_node_index_t path_index)
{
    mfib_path_ext_t *path_ext;

    path_ext = mfib_entry_path_ext_find(msrc->mfes_exts, path_index);

    hash_unset(msrc->mfes_exts, path_index);
    pool_put(mfib_path_ext_pool, path_ext);
}

typedef struct mfib_entry_collect_forwarding_ctx_t_
{
    load_balance_path_t * next_hops;
    fib_forward_chain_type_t fct;
    mfib_entry_src_t *msrc;
} mfib_entry_collect_forwarding_ctx_t;

static fib_path_list_walk_rc_t
mfib_entry_src_collect_forwarding (fib_node_index_t pl_index,
                                   fib_node_index_t path_index,
                                   void *arg)
{
    mfib_entry_collect_forwarding_ctx_t *ctx;
    load_balance_path_t *nh;

    ctx = arg;

    /*
     * if the path is not resolved, don't include it.
     */
    if (!fib_path_is_resolved(path_index))
    {
        return (FIB_PATH_LIST_WALK_CONTINUE);
    }

    /*
     * If the path is not forwarding to use it
     */
    mfib_path_ext_t *path_ext;
    
    path_ext = mfib_entry_path_ext_find(ctx->msrc->mfes_exts,
                                        path_index);

    if (NULL != path_ext &&
        !(path_ext->mfpe_flags & MFIB_ITF_FLAG_FORWARD))
    {
        return (FIB_PATH_LIST_WALK_CONTINUE);
    }
    
    switch (ctx->fct)
    {
    case FIB_FORW_CHAIN_TYPE_MCAST_IP4:
    case FIB_FORW_CHAIN_TYPE_MCAST_IP6:
        /*
         * EOS traffic with no label to stack, we need the IP Adj
         */
        vec_add2(ctx->next_hops, nh, 1);

        nh->path_index = path_index;
        nh->path_weight = fib_path_get_weight(path_index);
        fib_path_contribute_forwarding(path_index, ctx->fct, &nh->path_dpo);
        break;

    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_MPLS_EOS:
    case FIB_FORW_CHAIN_TYPE_ETHERNET:
    case FIB_FORW_CHAIN_TYPE_NSH:
    case FIB_FORW_CHAIN_TYPE_BIER:
        ASSERT(0);
        break;
    }

    return (FIB_PATH_LIST_WALK_CONTINUE);
}

static void
mfib_entry_stack (mfib_entry_t *mfib_entry,
                  mfib_entry_src_t *msrc)
{
    dpo_proto_t dp;

    dp = fib_proto_to_dpo(mfib_entry_get_proto(mfib_entry));

    /*
     * unlink the enty from the previous path list.
     */
    if (FIB_NODE_INDEX_INVALID != mfib_entry->mfe_pl)
    {
        fib_path_list_child_remove(mfib_entry->mfe_pl,
                                   mfib_entry->mfe_sibling);
    }

    if (NULL != msrc &&
        FIB_NODE_INDEX_INVALID != msrc->mfes_pl)
    {
        mfib_entry_collect_forwarding_ctx_t ctx = {
            .next_hops = NULL,
            .fct = mfib_entry_get_default_chain_type(mfib_entry),
            .msrc = msrc,
        };

        fib_path_list_walk(msrc->mfes_pl,
                           mfib_entry_src_collect_forwarding,
                           &ctx);

        if (!(MFIB_ENTRY_FLAG_EXCLUSIVE & mfib_entry->mfe_flags))
        {
            if (NULL == ctx.next_hops)
            {
                /*
                 * no next-hops, stack directly on the drop
                 */
                dpo_stack(DPO_MFIB_ENTRY, dp,
                          &mfib_entry->mfe_rep,
                          drop_dpo_get(dp));
            }
            else
            {
                /*
                 * each path contirbutes a next-hop. form a replicate
                 * from those choices.
                 */
                if (!dpo_id_is_valid(&mfib_entry->mfe_rep) ||
                    dpo_is_drop(&mfib_entry->mfe_rep))
                {
                    dpo_id_t tmp_dpo = DPO_INVALID;

                    dpo_set(&tmp_dpo,
                            DPO_REPLICATE, dp,
                            replicate_create(0, dp));

                    dpo_stack(DPO_MFIB_ENTRY, dp,
                              &mfib_entry->mfe_rep,
                              &tmp_dpo);

                    dpo_reset(&tmp_dpo);
                }
                replicate_multipath_update(&mfib_entry->mfe_rep,
                                           ctx.next_hops);
            }
        }
        else
        {
            /*
             * for exclusive routes the source provided a replicate DPO
             * we we stashed inthe special path list with one path
             * so we can stack directly on that.
             */
            ASSERT(1 == vec_len(ctx.next_hops));

            dpo_stack(DPO_MFIB_ENTRY, dp,
                      &mfib_entry->mfe_rep,
                      &ctx.next_hops[0].path_dpo);
            dpo_reset(&ctx.next_hops[0].path_dpo);
            vec_free(ctx.next_hops);
        }

        /*
         * link the entry to the path-list.
         * The entry needs to be a child so that we receive the back-walk
         * updates to recalculate forwarding.
         */
        mfib_entry->mfe_pl = msrc->mfes_pl;
        mfib_entry->mfe_sibling =
            fib_path_list_child_add(mfib_entry->mfe_pl,
                                    FIB_NODE_TYPE_MFIB_ENTRY,
                                    mfib_entry_get_index(mfib_entry));
    }
    else
    {
        dpo_stack(DPO_MFIB_ENTRY, dp,
                  &mfib_entry->mfe_rep,
                  drop_dpo_get(dp));
    }
}

static fib_node_index_t
mfib_entry_src_path_add (mfib_entry_src_t *msrc,
                         const fib_route_path_t *rpath)
{
    fib_node_index_t path_index;
    fib_route_path_t *rpaths;

    ASSERT(!(MFIB_ENTRY_FLAG_EXCLUSIVE & msrc->mfes_flags));

    /*
     * path-lists require a vector of paths
     */
    rpaths = NULL;
    vec_add1(rpaths, rpath[0]);

    if (FIB_NODE_INDEX_INVALID == msrc->mfes_pl)
    {
        /* A non-shared path-list */
        msrc->mfes_pl = fib_path_list_create(FIB_PATH_LIST_FLAG_NO_URPF,
                                             NULL);
        fib_path_list_lock(msrc->mfes_pl);
    }

    path_index = fib_path_list_path_add(msrc->mfes_pl, rpaths);

    vec_free(rpaths);

    return (path_index);
}

static fib_node_index_t
mfib_entry_src_path_remove (mfib_entry_src_t *msrc,
                            const fib_route_path_t *rpath)
{
    fib_node_index_t path_index;
    fib_route_path_t *rpaths;

    ASSERT(!(MFIB_ENTRY_FLAG_EXCLUSIVE & msrc->mfes_flags));

    /*
     * path-lists require a vector of paths
     */
    rpaths = NULL;
    vec_add1(rpaths, rpath[0]);

    path_index = fib_path_list_path_remove(msrc->mfes_pl, rpaths);

    vec_free(rpaths);

    return (path_index);
}

static void
mfib_entry_recalculate_forwarding (mfib_entry_t *mfib_entry)
{
    mfib_entry_src_t *bsrc;

    /*
     * copy the forwarding data from the bast source
     */
    bsrc = mfib_entry_get_best_src(mfib_entry);

    if (NULL != bsrc)
    {
        mfib_entry->mfe_flags = bsrc->mfes_flags;
        mfib_entry->mfe_itfs = bsrc->mfes_itfs;
        mfib_entry->mfe_rpf_id = bsrc->mfes_rpf_id;
    }

    mfib_entry_stack(mfib_entry, bsrc);
}


fib_node_index_t
mfib_entry_create (u32 fib_index,
                   mfib_source_t source,
                   const mfib_prefix_t *prefix,
                   fib_rpf_id_t rpf_id,
                   mfib_entry_flags_t entry_flags)
{
    fib_node_index_t mfib_entry_index;
    mfib_entry_t *mfib_entry;
    mfib_entry_src_t *msrc;

    mfib_entry = mfib_entry_alloc(fib_index, prefix,
                                  &mfib_entry_index);
    msrc = mfib_entry_src_find_or_create(mfib_entry, source);
    msrc->mfes_flags = entry_flags;
    msrc->mfes_rpf_id = rpf_id;

    mfib_entry_recalculate_forwarding(mfib_entry);

    return (mfib_entry_index);
}

static int
mfib_entry_ok_for_delete (mfib_entry_t *mfib_entry)
{
    return (0 == vec_len(mfib_entry->mfe_srcs));
}

static int
mfib_entry_src_ok_for_delete (const mfib_entry_src_t *msrc)
{
    return ((MFIB_ENTRY_FLAG_NONE == msrc->mfes_flags &&
             0 == fib_path_list_get_n_paths(msrc->mfes_pl)));
}

int
mfib_entry_update (fib_node_index_t mfib_entry_index,
                   mfib_source_t source,
                   mfib_entry_flags_t entry_flags,
                   fib_rpf_id_t rpf_id,
                   index_t repi)
{
    mfib_entry_t *mfib_entry;
    mfib_entry_src_t *msrc;

    mfib_entry = mfib_entry_get(mfib_entry_index);
    msrc = mfib_entry_src_find_or_create(mfib_entry, source);
    msrc->mfes_flags = entry_flags;
    msrc->mfes_rpf_id = rpf_id;

    if (INDEX_INVALID != repi)
    {
        /*
         * The source is providing its own replicate DPO.
         * Create a sepcial path-list to manage it, that way
         * this entry and the source are equivalent to a normal
         * entry
         */
        fib_node_index_t old_pl_index;
        dpo_proto_t dp;
        dpo_id_t dpo = DPO_INVALID;

        dp = fib_proto_to_dpo(mfib_entry_get_proto(mfib_entry));
        old_pl_index = msrc->mfes_pl;

        dpo_set(&dpo, DPO_REPLICATE, dp, repi);

        msrc->mfes_pl =
            fib_path_list_create_special(dp,
                                         FIB_PATH_LIST_FLAG_EXCLUSIVE,
                                         &dpo);

        dpo_reset(&dpo);
        fib_path_list_lock(msrc->mfes_pl);
        fib_path_list_unlock(old_pl_index);
    }

    if (mfib_entry_src_ok_for_delete(msrc))
    {
        /*
         * this source has no interfaces and no flags.
         * it has nothing left to give - remove it
         */
        mfib_entry_src_remove(mfib_entry, source);
    }

    mfib_entry_recalculate_forwarding(mfib_entry);

    return (mfib_entry_ok_for_delete(mfib_entry));
}

static void
mfib_entry_itf_add (mfib_entry_src_t *msrc,
                    u32 sw_if_index,
                    index_t mi)
{
    hash_set(msrc->mfes_itfs, sw_if_index, mi);
}

static void
mfib_entry_itf_remove (mfib_entry_src_t *msrc,
                       u32 sw_if_index)
{
    mfib_itf_t *mfi;

    mfi = mfib_entry_itf_find(msrc->mfes_itfs, sw_if_index);

    mfib_itf_delete(mfi);

    hash_unset(msrc->mfes_itfs, sw_if_index);
}

void
mfib_entry_path_update (fib_node_index_t mfib_entry_index,
                        mfib_source_t source,
                        const fib_route_path_t *rpath,
                        mfib_itf_flags_t itf_flags)
{
    fib_node_index_t path_index;
    mfib_path_ext_t *path_ext;
    mfib_entry_t *mfib_entry;
    mfib_entry_src_t *msrc;
    mfib_itf_flags_t old;

    mfib_entry = mfib_entry_get(mfib_entry_index);
    ASSERT(NULL != mfib_entry);
    msrc = mfib_entry_src_find_or_create(mfib_entry, source);

    /*
     * add the path to the path-list. If it's a duplicate we'll get
     * back the original path.
     */
    path_index = mfib_entry_src_path_add(msrc, rpath);

    /*
     * find the path extension for that path
     */
    path_ext = mfib_entry_path_ext_find(msrc->mfes_exts, path_index);

    if (NULL == path_ext)
    {
        old = MFIB_ITF_FLAG_NONE;
        path_ext = mfib_path_ext_add(msrc, path_index, itf_flags);
    }
    else
    {
        old = path_ext->mfpe_flags;
        path_ext->mfpe_flags = itf_flags;
    }

    /*
     * Has the path changed its contribution to the input interface set.
     * Which only paths with interfaces can do...
     */
    if (~0 != rpath[0].frp_sw_if_index)
    {
        mfib_itf_t *mfib_itf;

        if (old != itf_flags)
        {
            /*
             * change of flag contributions
             */
            mfib_itf = mfib_entry_itf_find(msrc->mfes_itfs,
                                           rpath[0].frp_sw_if_index);

            if (NULL == mfib_itf)
            {
                mfib_entry_itf_add(msrc,
                                   rpath[0].frp_sw_if_index,
                                   mfib_itf_create(path_index, itf_flags));
            }
            else
            {
                if (mfib_itf_update(mfib_itf,
                                    path_index,
                                    itf_flags))
                {
                    /*
                     * no more interface flags on this path, remove
                     * from the data-plane set
                     */
                    mfib_entry_itf_remove(msrc, rpath[0].frp_sw_if_index);
                }
            }
        }
    }

    mfib_entry_recalculate_forwarding(mfib_entry);
}

/*
 * mfib_entry_path_remove
 *
 * remove a path from the entry.
 * return the mfib_entry's index if it is still present, INVALID otherwise.
 */
int
mfib_entry_path_remove (fib_node_index_t mfib_entry_index,
                        mfib_source_t source,
                        const fib_route_path_t *rpath)
{
    fib_node_index_t path_index;
    mfib_entry_t *mfib_entry;
    mfib_entry_src_t *msrc;

    mfib_entry = mfib_entry_get(mfib_entry_index);
    ASSERT(NULL != mfib_entry);
    msrc = mfib_entry_src_find(mfib_entry, source, NULL);

    if (NULL == msrc)
    {
        /*
         * there are no paths left for this source
         */
        return (mfib_entry_ok_for_delete(mfib_entry));
    }

    /*
     * remove the path from the path-list. If it's not there we'll get
     * back invalid
     */
    path_index = mfib_entry_src_path_remove(msrc, rpath);

    if (FIB_NODE_INDEX_INVALID != path_index)
    {
        /*
         * don't need the extension, nor the interface anymore
         */
        mfib_path_ext_remove(msrc, path_index);
        if (~0 != rpath[0].frp_sw_if_index)
        {
            mfib_itf_t *mfib_itf;

            mfib_itf = mfib_entry_itf_find(msrc->mfes_itfs,
                                           rpath[0].frp_sw_if_index);

            if (mfib_itf_update(mfib_itf,
                                path_index,
                                MFIB_ITF_FLAG_NONE))
            {
                /*
                 * no more interface flags on this path, remove
                 * from the data-plane set
                 */
                mfib_entry_itf_remove(msrc, rpath[0].frp_sw_if_index);
            }
        }
    }

    if (mfib_entry_src_ok_for_delete(msrc))
    {
        /*
         * this source has no interfaces and no flags.
         * it has nothing left to give - remove it
         */
        mfib_entry_src_remove(mfib_entry, source);
    }

    mfib_entry_recalculate_forwarding(mfib_entry);

    return (mfib_entry_ok_for_delete(mfib_entry));
}

/**
 * mfib_entry_delete
 *
 * The source is withdrawing all the paths it provided
 */
int
mfib_entry_delete (fib_node_index_t mfib_entry_index,
                   mfib_source_t source)
{
    mfib_entry_t *mfib_entry;

    mfib_entry = mfib_entry_get(mfib_entry_index);
    mfib_entry_src_remove(mfib_entry, source);

    mfib_entry_recalculate_forwarding(mfib_entry);

    return (mfib_entry_ok_for_delete(mfib_entry));
}

static int
fib_ip4_address_compare (ip4_address_t * a1,
                         ip4_address_t * a2)
{
    /*
     * IP addresses are unsiged 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 undefiend, 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 (ip6_address_t * a1,
                         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
mfib_entry_cmp (fib_node_index_t mfib_entry_index1,
                fib_node_index_t mfib_entry_index2)
{
    mfib_entry_t *mfib_entry1, *mfib_entry2;
    int cmp = 0;

    mfib_entry1 = mfib_entry_get(mfib_entry_index1);
    mfib_entry2 = mfib_entry_get(mfib_entry_index2);

    switch (mfib_entry1->mfe_prefix.fp_proto)
    {
    case FIB_PROTOCOL_IP4:
        cmp = fib_ip4_address_compare(&mfib_entry1->mfe_prefix.fp_grp_addr.ip4,
                                      &mfib_entry2->mfe_prefix.fp_grp_addr.ip4);

        if (0 == cmp)
        {
            cmp = fib_ip4_address_compare(&mfib_entry1->mfe_prefix.fp_src_addr.ip4,
                                          &mfib_entry2->mfe_prefix.fp_src_addr.ip4);
        }
        break;
    case FIB_PROTOCOL_IP6:
        cmp = fib_ip6_address_compare(&mfib_entry1->mfe_prefix.fp_grp_addr.ip6,
                                      &mfib_entry2->mfe_prefix.fp_grp_addr.ip6);

        if (0 == cmp)
        {
            cmp = fib_ip6_address_compare(&mfib_entry1->mfe_prefix.fp_src_addr.ip6,
                                          &mfib_entry2->mfe_prefix.fp_src_addr.ip6);
        }
        break;
    case FIB_PROTOCOL_MPLS:
        ASSERT(0);
        cmp = 0;
        break;
    }

    if (0 == cmp) {
        cmp = (mfib_entry1->mfe_prefix.fp_len - mfib_entry2->mfe_prefix.fp_len);
    }
    return (cmp);
}

int
mfib_entry_cmp_for_sort (void *i1, void *i2)
{
    fib_node_index_t *mfib_entry_index1 = i1, *mfib_entry_index2 = i2;

    return (mfib_entry_cmp(*mfib_entry_index1,
                           *mfib_entry_index2));
}

static void
mfib_entry_last_lock_gone (fib_node_t *node)
{
    mfib_entry_t *mfib_entry;
    mfib_entry_src_t *msrc;

    mfib_entry = mfib_entry_from_fib_node(node);

    dpo_reset(&mfib_entry->mfe_rep);

    MFIB_ENTRY_DBG(mfib_entry, "last-lock");

    vec_foreach(msrc, mfib_entry->mfe_srcs)
    {
        mfib_entry_src_flush(msrc);
    }

    vec_free(mfib_entry->mfe_srcs);

    fib_node_deinit(&mfib_entry->mfe_node);
    pool_put(mfib_entry_pool, mfib_entry);
}

/*
 * mfib_entry_back_walk_notify
 *
 * A back walk has reach this entry.
 */
static fib_node_back_walk_rc_t
mfib_entry_back_walk_notify (fib_node_t *node,
                            fib_node_back_walk_ctx_t *ctx)
{
    mfib_entry_recalculate_forwarding(mfib_entry_from_fib_node(node));

    return (FIB_NODE_BACK_WALK_CONTINUE);
}

static void
mfib_entry_show_memory (void)
{
    fib_show_memory_usage("multicast-Entry",
                          pool_elts(mfib_entry_pool),
                          pool_len(mfib_entry_pool),
                          sizeof(mfib_entry_t));
}

/*
 * The MFIB entry's graph node virtual function table
 */
static const fib_node_vft_t mfib_entry_vft = {
    .fnv_get = mfib_entry_get_node,
    .fnv_last_lock = mfib_entry_last_lock_gone,
    .fnv_back_walk = mfib_entry_back_walk_notify,
    .fnv_mem_show = mfib_entry_show_memory,
};

void
mfib_entry_lock (fib_node_index_t mfib_entry_index)
{
    mfib_entry_t *mfib_entry;

    mfib_entry = mfib_entry_get(mfib_entry_index);

    fib_node_lock(&mfib_entry->mfe_node);
}

void
mfib_entry_unlock (fib_node_index_t mfib_entry_index)
{
    mfib_entry_t *mfib_entry;

    mfib_entry = mfib_entry_get(mfib_entry_index);

    fib_node_unlock(&mfib_entry->mfe_node);
}

static void
mfib_entry_dpo_lock (dpo_id_t *dpo)
{
}
static void
mfib_entry_dpo_unlock (dpo_id_t *dpo)
{
}

const static dpo_vft_t mfib_entry_dpo_vft = {
    .dv_lock = mfib_entry_dpo_lock,
    .dv_unlock = mfib_entry_dpo_unlock,
    .dv_format = format_mfib_entry_dpo,
    .dv_mem_show = mfib_entry_show_memory,
};

const static char* const mfib_entry_ip4_nodes[] =
{
    "ip4-mfib-forward-rpf",
    NULL,
};
const static char* const mfib_entry_ip6_nodes[] =
{
    "ip6-mfib-forward-rpf",
    NULL,
};

const static char* const * const mfib_entry_nodes[DPO_PROTO_NUM] =
{
    [DPO_PROTO_IP4]  = mfib_entry_ip4_nodes,
    [DPO_PROTO_IP6]  = mfib_entry_ip6_nodes,
};

void
mfib_entry_module_init (void)
{
    fib_node_register_type (FIB_NODE_TYPE_MFIB_ENTRY, &mfib_entry_vft);
    dpo_register(DPO_MFIB_ENTRY, &mfib_entry_dpo_vft, mfib_entry_nodes);
}

void
mfib_entry_encode (fib_node_index_t mfib_entry_index,
                  fib_route_path_encode_t **api_rpaths)
{
    mfib_entry_t *mfib_entry;
    mfib_entry_src_t *bsrc;

    mfib_entry = mfib_entry_get(mfib_entry_index);
    bsrc = mfib_entry_get_best_src(mfib_entry);

    if (FIB_NODE_INDEX_INVALID != bsrc->mfes_pl)
    {
        fib_path_list_walk(bsrc->mfes_pl,
                           fib_path_encode,
                           api_rpaths);
    }
}


void
mfib_entry_get_prefix (fib_node_index_t mfib_entry_index,
                      mfib_prefix_t *pfx)
{
    mfib_entry_t *mfib_entry;

    mfib_entry = mfib_entry_get(mfib_entry_index);
    *pfx = mfib_entry->mfe_prefix;
}

u32
mfib_entry_get_fib_index (fib_node_index_t mfib_entry_index)
{
    mfib_entry_t *mfib_entry;

    mfib_entry = mfib_entry_get(mfib_entry_index);

    return (mfib_entry->mfe_fib_index);
}

const dpo_id_t*
mfib_entry_contribute_ip_forwarding (fib_node_index_t mfib_entry_index)
{
    mfib_entry_t *mfib_entry;

    mfib_entry = mfib_entry_get(mfib_entry_index);

    return (&mfib_entry->mfe_rep);
}

void
mfib_entry_contribute_forwarding (fib_node_index_t mfib_entry_index,
                                  fib_forward_chain_type_t type,
                                  dpo_id_t *dpo)
{
    /*
     * An IP mFIB entry can only provide a forwarding chain that
     * is the same IP proto as the prefix.
     * No use-cases (i know of) for other combinations.
     */
    mfib_entry_t *mfib_entry;
    dpo_proto_t dp;

    mfib_entry = mfib_entry_get(mfib_entry_index);

    dp = fib_proto_to_dpo(mfib_entry->mfe_prefix.fp_proto);

    if (type == fib_forw_chain_type_from_dpo_proto(dp))
    {
        dpo_copy(dpo, &mfib_entry->mfe_rep);
    }
    else
    {
        dpo_copy(dpo, drop_dpo_get(dp));
    }
}

u32
mfib_entry_pool_size (void)
{
    return (pool_elts(mfib_entry_pool));
}

static clib_error_t *
show_mfib_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(mfib_entry_pool, fei))
        {
            vlib_cli_output (vm, "%d@%U",
                             fei,
                             format_mfib_entry, fei,
                             MFIB_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, mfib_entry_pool,
        ({
            vlib_cli_output (vm, "%d@%U",
                             fei,
                             format_mfib_entry, fei,
                             MFIB_ENTRY_FORMAT_BRIEF);
        }));
    }

    return (NULL);
}

/*?
 * This commnad displays an entry, or all entries, in the mfib tables indexed by their unique
 * numerical indentifier.
 ?*/
VLIB_CLI_COMMAND (show_mfib_entry, static) = {
  .path = "show mfib entry",
  .function = show_mfib_entry_command,
  .short_help = "show mfib entry",
};