summaryrefslogtreecommitdiffstats
path: root/src/vnet/fib/fib_api.c
blob: 12c4f0de13fe9935cc938ff383abffc5a5f184ab (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
/*
 * 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 <vnet/vnet.h>
#include <vlibmemory/api.h>
#include <vnet/fib/fib_api.h>
#include <vnet/fib/fib_table.h>
#include <vnet/mfib/mfib_table.h>
#include <vnet/bier/bier_disp_table.h>
#include <vnet/dpo/ip_null_dpo.h>

#include <vnet/vnet_msg_enum.h>

#define vl_typedefs		/* define message structures */
#include <vnet/vnet_all_api_h.h>
#undef vl_typedefs

#define vl_endianfun		/* define message structures */
#include <vnet/vnet_all_api_h.h>
#undef vl_endianfun

/* instantiate all the print functions we know about */
#define vl_print(handle, ...) vlib_cli_output (handle, __VA_ARGS__)
#define vl_printfun
#include <vnet/vnet_all_api_h.h>
#undef vl_printfun

#include <vlibapi/api_helper_macros.h>

int
fib_path_api_parse (const vl_api_fib_path_t *in,
                    fib_route_path_t *out)
{
    fib_route_path_flags_t path_flags;
    mpls_label_t next_hop_via_label;
    int rv = 0, n_labels;
    u8 ii;

    path_flags = FIB_ROUTE_PATH_FLAG_NONE;
    next_hop_via_label = ntohl (in->via_label);
    clib_memset(out, 0, sizeof(*out));
    out->frp_sw_if_index = ~0;

    out->frp_proto = in->afi;
    // .frp_addr = (NULL == next_hop ? zero_addr : *next_hop),
    out->frp_sw_if_index = ntohl(in->sw_if_index);
    out->frp_weight = in->weight;
    out->frp_preference = in->preference;

    if (DPO_PROTO_IP4 == out->frp_proto ||
        DPO_PROTO_IP6 == out->frp_proto ||
        DPO_PROTO_MPLS == out->frp_proto)
    {
        out->frp_fib_index = fib_table_find (dpo_proto_to_fib(out->frp_proto),
                                             ntohl (in->table_id));

        if (~0 == out->frp_fib_index)
            return (VNET_API_ERROR_NO_SUCH_FIB);
    }

    /*
     * the special INVALID label means we are not recursing via a
     * label. Exp-null value is never a valid via-label so that
     * also means it's not a via-label and means clients that set
     * it to 0 by default get the expected behaviour
     */
    if ((MPLS_LABEL_INVALID != next_hop_via_label) &&
        (0 != next_hop_via_label))
    {
        out->frp_proto = DPO_PROTO_MPLS;
        out->frp_local_label = next_hop_via_label;
        out->frp_eos = MPLS_NON_EOS;
    }

    n_labels = in->n_labels;
    if (n_labels == 0)
        ;
    else
    {
        vec_validate (out->frp_label_stack, n_labels - 1);
        for (ii = 0; ii < n_labels; ii++)
        {
            out->frp_label_stack[ii].fml_value =
                ntohl(in->label_stack[ii].label);
            out->frp_label_stack[ii].fml_ttl =
                in->label_stack[ii].ttl;
            out->frp_label_stack[ii].fml_exp =
                in->label_stack[ii].exp;
            out->frp_label_stack[ii].fml_mode =
                (in->label_stack[ii].is_uniform ?
                 FIB_MPLS_LSP_MODE_UNIFORM :
                 FIB_MPLS_LSP_MODE_PIPE);
        }
    }

    if (in->is_dvr)
        path_flags |= FIB_ROUTE_PATH_DVR;
    if (in->is_resolve_host)
        path_flags |= FIB_ROUTE_PATH_RESOLVE_VIA_HOST;
    if (in->is_resolve_attached)
        path_flags |= FIB_ROUTE_PATH_RESOLVE_VIA_ATTACHED;
    /* if (in->is_interface_rx) */
    /*     path_flags |= FIB_ROUTE_PATH_INTF_RX; */
    /* if (in->is_rpf_id) */
    /*     path_flags |= FIB_ROUTE_PATH_RPF_ID; */
    if (in->is_source_lookup)
        path_flags |= FIB_ROUTE_PATH_SOURCE_LOOKUP;

    if (in->is_udp_encap)
    {
        path_flags |= FIB_ROUTE_PATH_UDP_ENCAP;
        out->frp_udp_encap_id = ntohl(in->next_hop_id);
    }
    else
    {
        if (DPO_PROTO_IP4 == in->afi)
        {
            clib_memcpy (&out->frp_addr.ip4,
                         in->next_hop,
                         sizeof (out->frp_addr.ip4));
        }
        else if (DPO_PROTO_IP6 == in->afi)
        {
            clib_memcpy (&out->frp_addr.ip6,
                         in->next_hop,
                         sizeof (out->frp_addr.ip6));
        }

        if (ip46_address_is_zero(&out->frp_addr))
        {
            if (DPO_PROTO_BIER == in->afi)
            {
                index_t bdti;

                bdti = bier_disp_table_find(ntohl(in->table_id));

                if (INDEX_INVALID != bdti)
                {
                    out->frp_fib_index = bdti;
                    out->frp_proto = DPO_PROTO_BIER;
                }
                else
                {
                    rv = VNET_API_ERROR_NO_SUCH_FIB;
                }
            }
            else if (out->frp_sw_if_index == ~0 &&
                     out->frp_fib_index != ~0)
            {
                path_flags |= FIB_ROUTE_PATH_DEAG;
            }
        }
    }

    out->frp_flags = path_flags;

    return (rv);
}

void
fib_prefix_to_api (const fib_prefix_t *pfx,
                   u8 address[16],
                   u8 *length,
                   u8 *is_ip6)
{
    *length = pfx->fp_len;
    *is_ip6 = (FIB_PROTOCOL_IP6 == pfx->fp_proto ? 1 : 0);

    if (FIB_PROTOCOL_IP6 == pfx->fp_proto)
    {
        memcpy (address, &pfx->fp_addr.ip6, sizeof (pfx->fp_addr.ip6));
    }
    else
    {
        memcpy (address, &pfx->fp_addr.ip4, sizeof (pfx->fp_addr.ip4));
    }
}

static void
fib_api_path_copy_next_hop (const fib_route_path_encode_t * api_rpath, void *fp_arg)
{
  int is_ip4;
  vl_api_fib_path_t *fp = (vl_api_fib_path_t *) fp_arg;

  if (api_rpath->rpath.frp_proto == DPO_PROTO_IP4)
    fp->afi = IP46_TYPE_IP4;
  else if (api_rpath->rpath.frp_proto == DPO_PROTO_IP6)
    fp->afi = IP46_TYPE_IP6;
  else
    {
      is_ip4 = ip46_address_is_ip4 (&api_rpath->rpath.frp_addr);
      if (is_ip4)
	fp->afi = IP46_TYPE_IP4;
      else
	fp->afi = IP46_TYPE_IP6;
    }
  if (fp->afi == IP46_TYPE_IP4)
    memcpy (fp->next_hop, &api_rpath->rpath.frp_addr.ip4,
	    sizeof (api_rpath->rpath.frp_addr.ip4));
  else
    memcpy (fp->next_hop, &api_rpath->rpath.frp_addr.ip6,
	    sizeof (api_rpath->rpath.frp_addr.ip6));
}

void
fib_api_path_encode (const fib_route_path_encode_t * api_rpath,
                     vl_api_fib_path_t *out)
{
    int ii;

    clib_memset (out, 0, sizeof (*out));
    switch (api_rpath->dpo.dpoi_type)
    {
    case DPO_RECEIVE:
        out->is_local = true;
        break;
    case DPO_DROP:
        out->is_drop = true;
        break;
    case DPO_IP_NULL:
        switch (ip_null_dpo_get_action(api_rpath->dpo.dpoi_index))
        {
        case IP_NULL_ACTION_NONE:
            out->is_drop = true;
            break;
        case IP_NULL_ACTION_SEND_ICMP_UNREACH:
            out->is_unreach = true;
            break;
        case IP_NULL_ACTION_SEND_ICMP_PROHIBIT:
            out->is_prohibit = true;
            break;
        default:
            break;
        }
        break;
    default:
        break;
    }
    out->weight = api_rpath->rpath.frp_weight;
    out->preference = api_rpath->rpath.frp_preference;
    out->sw_if_index = htonl (api_rpath->rpath.frp_sw_if_index);
    out->afi = api_rpath->rpath.frp_proto;
    fib_api_path_copy_next_hop (api_rpath, out);

    if (0 != api_rpath->rpath.frp_fib_index)
    {
        if ((DPO_PROTO_IP6 == api_rpath->rpath.frp_proto) ||
            (DPO_PROTO_IP4 == api_rpath->rpath.frp_proto))
        {
            if (api_rpath->rpath.frp_flags & FIB_ROUTE_PATH_RPF_ID)
            {
                out->table_id =
                    htonl(mfib_table_get_table_id(
                              api_rpath->rpath.frp_fib_index,
                              dpo_proto_to_fib(api_rpath->rpath.frp_proto)));
            }
            else
            {
                out->table_id =
                    htonl(fib_table_get_table_id(
                              api_rpath->rpath.frp_fib_index,
                              dpo_proto_to_fib(api_rpath->rpath.frp_proto)));
            }
        }
    }

    if (api_rpath->rpath.frp_flags & FIB_ROUTE_PATH_DVR)
    {
        out->is_dvr = 1;
    }
    if (api_rpath->rpath.frp_flags & FIB_ROUTE_PATH_UDP_ENCAP)
    {
        out->is_udp_encap = 1;
        out->next_hop_id = api_rpath->rpath.frp_udp_encap_id;
    }
    if (api_rpath->rpath.frp_flags & FIB_ROUTE_PATH_INTF_RX)
    {
        out->is_interface_rx = 1;
    }
    if (api_rpath->rpath.frp_flags & FIB_ROUTE_PATH_LOCAL)
    {
        out->is_local = 1;
    }
    if (api_rpath->rpath.frp_flags & FIB_ROUTE_PATH_RESOLVE_VIA_HOST)
    {
        out->is_resolve_host = 1;
    }
    if (api_rpath->rpath.frp_flags & FIB_ROUTE_PATH_RESOLVE_VIA_ATTACHED)
    {
        out->is_resolve_attached = 1;
    }
    /* if (api_rpath->rpath.frp_flags & FIB_ROUTE_PATH_ATTACHED) { */
    /*     out->is_attached = 1; */
    /* } */
    /* if (api_rpath->rpath.frp_flags & FIB_ROUTE_PATH_CONNECTED) { */
    /*     out->is_connected = 1; */
    /* } */
    if (api_rpath->rpath.frp_label_stack)
    {
        for (ii = 0; ii < vec_len(api_rpath->rpath.frp_label_stack); ii++)
        {
            out->label_stack[ii].label =
                htonl(api_rpath->rpath.frp_label_stack[ii].fml_value);
            out->label_stack[ii].ttl =
                api_rpath->rpath.frp_label_stack[ii].fml_ttl;
            out->label_stack[ii].exp =
                api_rpath->rpath.frp_label_stack[ii].fml_exp;
        }
        out->n_labels = ii;
    }
}

fib_protocol_t
fib_proto_from_api_address_family (int af)
{
    switch (clib_net_to_host_u32 (af))
    {
    case ADDRESS_IP4:
        return (FIB_PROTOCOL_IP4);
    case ADDRESS_IP6:
        return (FIB_PROTOCOL_IP6);
    }

    ASSERT(0);
    return (FIB_PROTOCOL_IP4);
}

int
fib_proto_to_api_address_family (fib_protocol_t fproto)
{
    switch (fproto)
    {
    case FIB_PROTOCOL_IP4:
        return (clib_net_to_host_u32 (ADDRESS_IP4));
    case FIB_PROTOCOL_IP6:
        return (clib_net_to_host_u32 (ADDRESS_IP6));
    default:
        break;
    }

    ASSERT(0);
    return (clib_net_to_host_u32 (ADDRESS_IP4));
}
'>1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884
/*
 * 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 <vnet/adj/adj.h>
#include <vnet/dpo/load_balance.h>
#include <vnet/dpo/mpls_label_dpo.h>
#include <vnet/dpo/drop_dpo.h>
#include <vnet/dpo/replicate_dpo.h>

#include <vnet/fib/fib_entry_src.h>
#include <vnet/fib/fib_table.h>
#include <vnet/fib/fib_path_ext.h>
#include <vnet/fib/fib_urpf_list.h>

/*
 * per-source type vft
 */
static fib_entry_src_vft_t fib_entry_src_vft[FIB_SOURCE_MAX];

/**
 * Get the VFT for a given source. This is a combination of the source
 * enum and the interposer flags
 */
const fib_entry_src_vft_t*
fib_entry_src_get_vft (const fib_entry_src_t *esrc)
{
    if (esrc->fes_entry_flags & FIB_ENTRY_FLAG_INTERPOSE)
    {
        return (&fib_entry_src_vft[FIB_SOURCE_INTERPOSE]);
    }

    return (&fib_entry_src_vft[esrc->fes_src]);
}

static void
fib_entry_src_copy_default (const fib_entry_src_t *orig_src,
                            const fib_entry_t *fib_entry,
                            fib_entry_src_t *copy_src)
{
    clib_memcpy(&copy_src->u, &orig_src->u, sizeof(copy_src->u));
}

void
fib_entry_src_register (fib_source_t source,
			const fib_entry_src_vft_t *vft)
{
    fib_entry_src_vft[source] = *vft;

    if (NULL == fib_entry_src_vft[source].fesv_copy)
    {
        fib_entry_src_vft[source].fesv_copy = fib_entry_src_copy_default;
    }
}

static int
fib_entry_src_cmp_for_sort (void * v1,
			    void * v2)
{
    fib_entry_src_t *esrc1 = v1, *esrc2 = v2;

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

static void
fib_entry_src_action_init (fib_entry_t *fib_entry,
			   fib_source_t source,
                           fib_entry_flag_t flags)
{
    fib_entry_src_t esrc = {
	.fes_pl = FIB_NODE_INDEX_INVALID,
	.fes_flags = FIB_ENTRY_SRC_FLAG_NONE,
	.fes_src = source,
        .fes_entry_flags = flags,
    };

    FIB_ENTRY_SRC_VFT_INVOKE(&esrc, fesv_init, (&esrc));

    vec_add1(fib_entry->fe_srcs, esrc);
    vec_sort_with_function(fib_entry->fe_srcs,
			   fib_entry_src_cmp_for_sort);
}

static fib_entry_src_t *
fib_entry_src_find_i (const fib_entry_t *fib_entry,
                      fib_source_t source,
                      u32 *index)

{
    fib_entry_src_t *esrc;
    int ii;

    ii = 0;
    vec_foreach(esrc, fib_entry->fe_srcs)
    {
	if (esrc->fes_src == source)
	{
	    if (NULL != index)
	    {
		*index = ii;
	    }
	    return (esrc);
	}
	else
	{
	    ii++;
	}
    }

    return (NULL);
}

static fib_entry_src_t *
fib_entry_src_find (const fib_entry_t *fib_entry,
		    fib_source_t source)

{
    return (fib_entry_src_find_i(fib_entry, source, NULL));
}

int
fib_entry_is_sourced (fib_node_index_t fib_entry_index,
                      fib_source_t source)
{
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fib_entry_index);

    return (NULL != fib_entry_src_find(fib_entry, source));
}

static fib_entry_src_t *
fib_entry_src_find_or_create (fib_entry_t *fib_entry,
			      fib_source_t source,
                              fib_entry_flag_t flags)
{
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find(fib_entry, source);

    if (NULL == esrc)
    {
	fib_entry_src_action_init(fib_entry, source, flags);
    }

    return (fib_entry_src_find(fib_entry, source));
}

static void
fib_entry_src_action_deinit (fib_entry_t *fib_entry,
			     fib_source_t source)

{
    fib_entry_src_t *esrc;
    u32 index = ~0;

    esrc = fib_entry_src_find_i(fib_entry, source, &index);

    ASSERT(NULL != esrc);

    FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_deinit, (esrc));

    fib_path_ext_list_flush(&esrc->fes_path_exts);
    vec_del1(fib_entry->fe_srcs, index);
}

fib_entry_src_cover_res_t
fib_entry_src_action_cover_change (fib_entry_t *fib_entry,
                                   fib_entry_src_t *esrc)
{
    FIB_ENTRY_SRC_VFT_INVOKE_AND_RETURN(esrc, fesv_cover_change,
                                        (esrc, fib_entry));

    fib_entry_src_cover_res_t res = {
	.install = !0,
	.bw_reason = FIB_NODE_BW_REASON_FLAG_NONE,
    };
    return (res);
}

fib_entry_src_cover_res_t
fib_entry_src_action_cover_update (fib_entry_t *fib_entry,
                                   fib_entry_src_t *esrc)
{
    FIB_ENTRY_SRC_VFT_INVOKE_AND_RETURN(esrc, fesv_cover_update,
                                        (esrc, fib_entry));

    fib_entry_src_cover_res_t res = {
	.install = !0,
	.bw_reason = FIB_NODE_BW_REASON_FLAG_NONE,
    };
    return (res);
}

typedef struct fib_entry_src_collect_forwarding_ctx_t_
{
    load_balance_path_t *next_hops;
    const fib_entry_t *fib_entry;
    const fib_entry_src_t *esrc;
    fib_forward_chain_type_t fct;
    int n_recursive_constrained;
    u16 preference;
} fib_entry_src_collect_forwarding_ctx_t;

/**
 * @brief Determine whether this FIB entry should use a load-balance MAP
 * to support PIC edge fast convergence
 */
load_balance_flags_t
fib_entry_calc_lb_flags (fib_entry_src_collect_forwarding_ctx_t *ctx)
{
    /**
     * We'll use a LB map if the path-list has multiple recursive paths.
     * recursive paths implies BGP, and hence scale.
     */
    if (ctx->n_recursive_constrained > 1 &&
        fib_path_list_is_popular(ctx->esrc->fes_pl))
    {
        return (LOAD_BALANCE_FLAG_USES_MAP);
    }
    return (LOAD_BALANCE_FLAG_NONE);
}

static int
fib_entry_src_valid_out_label (mpls_label_t label)
{
    return ((MPLS_LABEL_IS_REAL(label) ||
             MPLS_LABEL_POP == label ||
             MPLS_IETF_IPV4_EXPLICIT_NULL_LABEL == label ||
             MPLS_IETF_IPV6_EXPLICIT_NULL_LABEL == label ||
             MPLS_IETF_IMPLICIT_NULL_LABEL == label));
}

/**
 * @brief Turn the chain type requested by the client into the one they
 * really wanted
 */
fib_forward_chain_type_t
fib_entry_chain_type_fixup (const fib_entry_t *entry,
			    fib_forward_chain_type_t fct)
{
    /*
     * The EOS chain is a tricky since one cannot know the adjacency
     * to link to without knowing what the packets payload protocol
     * will be once the label is popped.
     */
    fib_forward_chain_type_t dfct;

    if (FIB_FORW_CHAIN_TYPE_MPLS_EOS != fct)
    {
        return (fct);
    }

    dfct = fib_entry_get_default_chain_type(entry);

    if (FIB_FORW_CHAIN_TYPE_MPLS_EOS == dfct)
    {
        /*
         * If the entry being asked is a eos-MPLS label entry,
         * then use the payload-protocol field, that we stashed there
         * for just this purpose
         */
        return (fib_forw_chain_type_from_dpo_proto(
                    entry->fe_prefix.fp_payload_proto));
    }
    /*
     * else give them what this entry would be by default. i.e. if it's a v6
     * entry, then the label its local labelled should be carrying v6 traffic.
     * If it's a non-EOS label entry, then there are more labels and we want
     * a non-eos chain.
     */
    return (dfct);
}

static dpo_proto_t
fib_prefix_get_payload_proto (const fib_prefix_t *pfx)
{
    switch (pfx->fp_proto)
    {
    case FIB_PROTOCOL_IP4:
        return (DPO_PROTO_IP4);
    case FIB_PROTOCOL_IP6:
        return (DPO_PROTO_IP6);
    case FIB_PROTOCOL_MPLS:
        return (pfx->fp_payload_proto);
    }

    ASSERT(0);
    return (DPO_PROTO_IP4);
}

static void
fib_entry_src_get_path_forwarding (fib_node_index_t path_index,
                                   fib_entry_src_collect_forwarding_ctx_t *ctx)
{
    load_balance_path_t *nh;

    /*
     * no extension => no out-going label for this path. that's OK
     * in the case of an IP or EOS chain, but not for non-EOS
     */
    switch (ctx->fct)
    {
    case FIB_FORW_CHAIN_TYPE_UNICAST_IP4:
    case FIB_FORW_CHAIN_TYPE_UNICAST_IP6:
    case FIB_FORW_CHAIN_TYPE_MCAST_IP4:
    case FIB_FORW_CHAIN_TYPE_MCAST_IP6:
    case FIB_FORW_CHAIN_TYPE_BIER:
        /*
         * 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_MPLS_NON_EOS:
        if (fib_path_is_exclusive(path_index) ||
            fib_path_is_deag(path_index))
        {
            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,
                                           FIB_FORW_CHAIN_TYPE_MPLS_NON_EOS,
                                           &nh->path_dpo);
        }
        break;
    case FIB_FORW_CHAIN_TYPE_MPLS_EOS:
        {
            /*
             * no label. we need a chain based on the payload. fixup.
             */
            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,
                                           fib_entry_chain_type_fixup(ctx->fib_entry,
                                                                      ctx->fct),
                                           &nh->path_dpo);
            fib_path_stack_mpls_disp(path_index,
                                     fib_prefix_get_payload_proto(&ctx->fib_entry->fe_prefix),
                                     FIB_MPLS_LSP_MODE_PIPE,
                                     &nh->path_dpo);

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

static fib_path_list_walk_rc_t
fib_entry_src_collect_forwarding (fib_node_index_t pl_index,
                                  fib_node_index_t path_index,
                                  void *arg)
{
    fib_entry_src_collect_forwarding_ctx_t *ctx;
    fib_path_ext_t *path_ext;
    u32 n_nhs;

    ctx = arg;
    n_nhs = vec_len(ctx->next_hops);

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

    if (fib_path_is_recursive_constrained(path_index))
    {
        ctx->n_recursive_constrained += 1;
    }
    if (0xffff == ctx->preference)
    {
        /*
         * not set a preference yet, so the first path we encounter
         * sets the preference we are collecting.
         */
        ctx->preference = fib_path_get_preference(path_index);
    }
    else if (ctx->preference != fib_path_get_preference(path_index))
    {
        /*
         * this path does not belong to the same preference as the
         * previous paths encountered. we are done now.
         */
        return (FIB_PATH_LIST_WALK_STOP);
    }

    /*
     * get the matching path-extension for the path being visited.
     */
    path_ext = fib_path_ext_list_find_by_path_index(&ctx->esrc->fes_path_exts,
                                                    path_index);

    if (NULL != path_ext)
    {
        switch (path_ext->fpe_type)
        {
        case FIB_PATH_EXT_MPLS:
            if (fib_entry_src_valid_out_label(path_ext->fpe_label_stack[0].fml_value))
            {
                /*
                 * found a matching extension. stack it to obtain the forwarding
                 * info for this path.
                 */
                ctx->next_hops =
                    fib_path_ext_stack(path_ext,
                                       ctx->fct,
                                       fib_entry_chain_type_fixup(ctx->fib_entry,
                                                                  ctx->fct),
                                       ctx->next_hops);
            }
            else
            {
                fib_entry_src_get_path_forwarding(path_index, ctx);
            }
            break;
        case FIB_PATH_EXT_ADJ:
            if (FIB_PATH_EXT_ADJ_FLAG_REFINES_COVER & path_ext->fpe_adj_flags)
            {
                fib_entry_src_get_path_forwarding(path_index, ctx);
            }
            /*
             * else
             *  the path does not refine the cover, meaning that
             *  the adjacency doesdoes not match the sub-net on the link.
             *  So this path does not contribute forwarding.
             */
            break;
        }
    }
    else
    {
        fib_entry_src_get_path_forwarding(path_index, ctx);
    }

    /*
     * a this point 'ctx' has the DPO the path contributed, plus
     * any labels from path extensions.
     * check if there are any interpose sources that want to contribute
     */
    if (n_nhs < vec_len(ctx->next_hops))
    {
        /*
         * the path contributed a new choice.
         */
        const fib_entry_src_vft_t *vft;

        vft = fib_entry_src_get_vft(ctx->esrc);

        if (NULL != vft->fesv_contribute_interpose)
        {
            const dpo_id_t *interposer;

            interposer = vft->fesv_contribute_interpose(ctx->esrc,
                                                        ctx->fib_entry);

            if (NULL != interposer)
            {
                dpo_id_t clone = DPO_INVALID;

                dpo_mk_interpose(interposer,
                                 &ctx->next_hops[n_nhs].path_dpo,
                                 &clone);

                dpo_copy(&ctx->next_hops[n_nhs].path_dpo, &clone);
                dpo_reset(&clone);
            }
        }
    }

    return (FIB_PATH_LIST_WALK_CONTINUE);
}

void
fib_entry_src_mk_lb (fib_entry_t *fib_entry,
		     const fib_entry_src_t *esrc,
		     fib_forward_chain_type_t fct,
		     dpo_id_t *dpo_lb)
{
    dpo_proto_t lb_proto;

    /*
     * If the entry has path extensions then we construct a load-balance
     * by stacking the extensions on the forwarding chains of the paths.
     * Otherwise we use the load-balance of the path-list
     */
    fib_entry_src_collect_forwarding_ctx_t ctx = {
        .esrc = esrc,
        .fib_entry = fib_entry,
        .next_hops = NULL,
        .n_recursive_constrained = 0,
        .fct = fct,
        .preference = 0xffff,
    };

    /*
     * As an optimisation we allocate the vector of next-hops to be sized
     * equal to the maximum nuber of paths we will need, which is also the
     * most likely number we will need, since in most cases the paths are 'up'.
     */
    vec_validate(ctx.next_hops, fib_path_list_get_n_paths(esrc->fes_pl));
    vec_reset_length(ctx.next_hops);

    lb_proto = fib_forw_chain_type_to_dpo_proto(fct);

    fib_path_list_walk(esrc->fes_pl,
                       fib_entry_src_collect_forwarding,
                       &ctx);

    if (esrc->fes_entry_flags & FIB_ENTRY_FLAG_EXCLUSIVE)
    {
	/*
	 * the client provided the DPO that the entry should link to.
	 * all entries must link to a LB, so if it is an LB already
	 * then we can use it.
	 */
	if ((1 == vec_len(ctx.next_hops)) &&
	    (DPO_LOAD_BALANCE == ctx.next_hops[0].path_dpo.dpoi_type))
	{
	    dpo_copy(dpo_lb, &ctx.next_hops[0].path_dpo);
	    dpo_reset(&ctx.next_hops[0].path_dpo);
	    return;
	}
    }

    if (!dpo_id_is_valid(dpo_lb))
    {
        /*
         * first time create
         */
        if (esrc->fes_entry_flags & FIB_ENTRY_FLAG_MULTICAST)
        {
            dpo_set(dpo_lb,
                    DPO_REPLICATE,
                    lb_proto,
                    MPLS_IS_REPLICATE | replicate_create(0, lb_proto));
        }
        else
        {
            fib_protocol_t flow_hash_proto;
            flow_hash_config_t fhc;

            /*
             * if the protocol for the LB we are building does not match that
             * of the fib_entry (i.e. we are build the [n]EOS LB for an IPv[46]
             * then the fib_index is not an index that relates to the table
             * type we need. So get the default flow-hash config instead.
             */
            flow_hash_proto = dpo_proto_to_fib(lb_proto);
            if (fib_entry->fe_prefix.fp_proto != flow_hash_proto)
            {
                fhc = fib_table_get_default_flow_hash_config(flow_hash_proto);
            }
            else
            {
                fhc = fib_table_get_flow_hash_config(fib_entry->fe_fib_index,
                                                     flow_hash_proto);
            }

            dpo_set(dpo_lb,
                    DPO_LOAD_BALANCE,
                    lb_proto,
                    load_balance_create(0, lb_proto, fhc));
        }
    }

    if (esrc->fes_entry_flags & FIB_ENTRY_FLAG_MULTICAST)
    {
        /*
         * MPLS multicast
         */
        replicate_multipath_update(dpo_lb, ctx.next_hops);
    }
    else
    {
        load_balance_multipath_update(dpo_lb,
                                      ctx.next_hops,
                                      fib_entry_calc_lb_flags(&ctx));
        vec_free(ctx.next_hops);

        /*
         * if this entry is sourced by the uRPF-exempt source then we
         * append the always present local0 interface (index 0) to the
         * uRPF list so it is not empty. that way packets pass the loose check.
         */
        index_t ui = fib_path_list_get_urpf(esrc->fes_pl);

        if ((fib_entry_is_sourced(fib_entry_get_index(fib_entry),
                                  FIB_SOURCE_URPF_EXEMPT) ||
             (esrc->fes_entry_flags & FIB_ENTRY_FLAG_LOOSE_URPF_EXEMPT))&&
            (0 == fib_urpf_check_size(ui)))
        {
            /*
             * The uRPF list we get from the path-list is shared by all
             * other users of the list, but the uRPF exemption applies
             * only to this prefix. So we need our own list.
             */
            ui = fib_urpf_list_alloc_and_lock();
            fib_urpf_list_append(ui, 0);
            fib_urpf_list_bake(ui);
            load_balance_set_urpf(dpo_lb->dpoi_index, ui);
            fib_urpf_list_unlock(ui);
        }
        else
        {
            load_balance_set_urpf(dpo_lb->dpoi_index, ui);
        }
        load_balance_set_fib_entry_flags(dpo_lb->dpoi_index,
                                         fib_entry_get_flags_i(fib_entry));
    }
}

void
fib_entry_src_action_install (fib_entry_t *fib_entry,
			      fib_source_t source)
{
    /*
     * Install the forwarding chain for the given source into the forwarding
     * tables
     */
    fib_forward_chain_type_t fct;
    fib_entry_src_t *esrc;
    int insert;

    fct = fib_entry_get_default_chain_type(fib_entry);
    esrc = fib_entry_src_find(fib_entry, source);

    /*
     * Every entry has its own load-balance object. All changes to the entry's
     * forwarding result in an inplace modify of the load-balance. This means
     * the load-balance object only needs to be added to the forwarding
     * DB once, when it is created.
     */
    insert = !dpo_id_is_valid(&fib_entry->fe_lb);

    fib_entry_src_mk_lb(fib_entry, esrc, fct, &fib_entry->fe_lb);

    ASSERT(dpo_id_is_valid(&fib_entry->fe_lb));
    FIB_ENTRY_DBG(fib_entry, "install: %d", fib_entry->fe_lb);

    /*
     * insert the adj into the data-plane forwarding trie
     */
    if (insert)
    {
       fib_table_fwding_dpo_update(fib_entry->fe_fib_index,
                                   &fib_entry->fe_prefix,
                                   &fib_entry->fe_lb);
    }

    /*
     * if any of the other chain types are already created they will need
     * updating too
     */
    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, esrc,
                            fib_entry_delegate_type_to_chain_type(fdt),
                            &fed->fd_dpo);
    });
}

void
fib_entry_src_action_uninstall (fib_entry_t *fib_entry)
{
    /*
     * uninstall the forwarding chain from the forwarding tables
     */
    FIB_ENTRY_DBG(fib_entry, "uninstall: %d",
		  fib_entry->fe_adj_index);

    if (dpo_id_is_valid(&fib_entry->fe_lb))
    {
	fib_table_fwding_dpo_remove(
	    fib_entry->fe_fib_index,
	    &fib_entry->fe_prefix,
	    &fib_entry->fe_lb);

	dpo_reset(&fib_entry->fe_lb);
    }
}

static void
fib_entry_recursive_loop_detect_i (fib_node_index_t path_list_index)
{
    fib_node_index_t *entries = NULL;

    fib_path_list_recursive_loop_detect(path_list_index, &entries);

    vec_free(entries);
}

/*
 * fib_entry_src_action_copy
 *
 * copy a source data from another entry to this one
 */
static fib_entry_t *
fib_entry_src_action_copy (fib_entry_t *fib_entry,
                           const fib_entry_src_t *orig_src)
{
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find_or_create(fib_entry,
                                        orig_src->fes_src,
                                        orig_src->fes_entry_flags);

    FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_copy,
                             (orig_src, fib_entry, esrc));

    fib_path_list_unlock(esrc->fes_pl);

    /*
     * copy over all the data ...
     */
    esrc->fes_flags = orig_src->fes_flags;
    esrc->fes_pl = orig_src->fes_pl;

    /*
     *  ... then update
     */
    esrc->fes_ref_count = 1;
    esrc->fes_flags |= FIB_ENTRY_SRC_FLAG_INHERITED;
    esrc->fes_flags &= ~(FIB_ENTRY_SRC_FLAG_ACTIVE |
                         FIB_ENTRY_SRC_FLAG_CONTRIBUTING);
    esrc->fes_entry_flags &= ~FIB_ENTRY_FLAG_COVERED_INHERIT;

    /*
     * the source owns a lock on the entry
     */
    fib_path_list_lock(esrc->fes_pl);
    fib_entry_lock(fib_entry_get_index(fib_entry));

    return (fib_entry);
}

/*
 * fib_entry_src_action_update
 *
 * copy a source data from another entry to this one
 */
static fib_entry_src_t *
fib_entry_src_action_update_from_cover (fib_entry_t *fib_entry,
                                        const fib_entry_src_t *orig_src)
{
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find_or_create(fib_entry,
                                        orig_src->fes_src,
                                        orig_src->fes_entry_flags);

    /*
     * the source owns a lock on the entry
     */
    fib_path_list_unlock(esrc->fes_pl);
    esrc->fes_pl = orig_src->fes_pl;
    fib_path_list_lock(esrc->fes_pl);

    return (esrc);
}

static fib_table_walk_rc_t
fib_entry_src_covered_inherit_add_i (fib_entry_t *fib_entry,
                                     const fib_entry_src_t *cover_src)
{
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find(fib_entry, cover_src->fes_src);

    if (cover_src == esrc)
    {
        return (FIB_TABLE_WALK_CONTINUE);
    }

    if (NULL != esrc)
    {
        /*
         * the covered entry already has this source.
         */
        if (esrc->fes_entry_flags & FIB_ENTRY_FLAG_COVERED_INHERIT)
        {
            /*
             * the covered source is itself a COVERED_INHERIT, i.e.
             * it also pushes this source down the sub-tree.
             * We consider this more specfic covered to be the owner
             * of the sub-tree from this point down.
             */
            return (FIB_TABLE_WALK_SUB_TREE_STOP);
        }
        if (esrc->fes_flags & FIB_ENTRY_SRC_FLAG_INHERITED)
        {
            /*
             * The covered's source data has been inherited, presumably
             * from this cover, i.e. this is a modify.
             */
            esrc = fib_entry_src_action_update_from_cover(fib_entry, cover_src);
            fib_entry_source_change(fib_entry, esrc->fes_src, esrc->fes_src);
        }
        else
        {
            /*
             * The covered's source was not inherited and it is also
             * not inherting. Nevertheless, it still owns the sub-tree from 
             * this point down.
             */
            return (FIB_TABLE_WALK_SUB_TREE_STOP);
        }
    }
    else
    {
        /*
         * The covered does not have this source - add it.
         */
        fib_source_t best_source;

        best_source = fib_entry_get_best_source(
            fib_entry_get_index(fib_entry));

        fib_entry_src_action_copy(fib_entry, cover_src);
        fib_entry_source_change(fib_entry, best_source, cover_src->fes_src);

    }
    return (FIB_TABLE_WALK_CONTINUE);
}

static fib_table_walk_rc_t
fib_entry_src_covered_inherit_walk_add (fib_node_index_t fei,
                                        void *ctx)
{
    return (fib_entry_src_covered_inherit_add_i(fib_entry_get(fei), ctx));
}

static fib_table_walk_rc_t
fib_entry_src_covered_inherit_walk_remove (fib_node_index_t fei,
                                           void *ctx)
{
    fib_entry_src_t *cover_src, *esrc;
    fib_entry_t *fib_entry;

    fib_entry = fib_entry_get(fei);

    cover_src = ctx;
    esrc = fib_entry_src_find(fib_entry, cover_src->fes_src);

    if (cover_src == esrc)
    {
        return (FIB_TABLE_WALK_CONTINUE);
    }

    if (NULL != esrc)
    {
        /*
         * the covered entry already has this source.
         */
        if (esrc->fes_entry_flags & FIB_ENTRY_FLAG_COVERED_INHERIT)
        {
            /*
             * the covered source is itself a COVERED_INHERIT, i.e.
             * it also pushes this source down the sub-tree.
             * We consider this more specfic covered to be the owner
             * of the sub-tree from this point down.
             */
            return (FIB_TABLE_WALK_SUB_TREE_STOP);
        }
        if (esrc->fes_flags & FIB_ENTRY_SRC_FLAG_INHERITED)
        {
            /*
             * The covered's source data has been inherited, presumably
             * from this cover
             */
            fib_entry_src_flag_t remaining;

            remaining = fib_entry_special_remove(fei, cover_src->fes_src);

            ASSERT(FIB_ENTRY_SRC_FLAG_ADDED == remaining);
        }
        else
        {
            /*
             * The covered's source was not inherited and it is also
             * not inherting. Nevertheless, it still owns the sub-tree from 
             * this point down.
             */
            return (FIB_TABLE_WALK_SUB_TREE_STOP);
        }
    }
    else
    {
        /*
         * The covered does not have this source - that's an error,
         * since it should have inherited, but there is nothing we can do
         * about it now.
         */
    }
    return (FIB_TABLE_WALK_CONTINUE);
}

void
fib_entry_src_inherit (const fib_entry_t *cover,
                       fib_entry_t *covered)
{
    CLIB_UNUSED(fib_source_t source);
    const fib_entry_src_t *src;

    FOR_EACH_SRC_ADDED(cover, src, source,
    ({
        if ((src->fes_entry_flags & FIB_ENTRY_FLAG_COVERED_INHERIT) ||
            (src->fes_flags & FIB_ENTRY_SRC_FLAG_INHERITED))
        {
            fib_entry_src_covered_inherit_add_i(covered, src);
        }
    }))
}

static void
fib_entry_src_covered_inherit_add (fib_entry_t *fib_entry,
                                   fib_source_t source)

{
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find(fib_entry, source);

    ASSERT(esrc->fes_flags & FIB_ENTRY_SRC_FLAG_ACTIVE);

    if ((esrc->fes_entry_flags & FIB_ENTRY_FLAG_COVERED_INHERIT) ||
        (esrc->fes_flags & FIB_ENTRY_SRC_FLAG_INHERITED))
    {
        fib_table_sub_tree_walk(fib_entry->fe_fib_index,
                                fib_entry->fe_prefix.fp_proto,
                                &fib_entry->fe_prefix,
                                fib_entry_src_covered_inherit_walk_add,
                                esrc);
    }
}

static void
fib_entry_src_covered_inherit_remove (fib_entry_t *fib_entry,
                                      fib_entry_src_t *esrc)

{
    ASSERT(!(esrc->fes_flags & FIB_ENTRY_SRC_FLAG_ACTIVE));

    if (esrc->fes_entry_flags & FIB_ENTRY_FLAG_COVERED_INHERIT)
    {
        fib_table_sub_tree_walk(fib_entry->fe_fib_index,
                                fib_entry->fe_prefix.fp_proto,
                                &fib_entry->fe_prefix,
                                fib_entry_src_covered_inherit_walk_remove,
                                esrc);
    }
}

void
fib_entry_src_action_activate (fib_entry_t *fib_entry,
			       fib_source_t source)

{
    int houston_we_are_go_for_install;
    const fib_entry_src_vft_t *vft;
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find(fib_entry, source);

    ASSERT(!(esrc->fes_flags & FIB_ENTRY_SRC_FLAG_ACTIVE));
    ASSERT(esrc->fes_flags & FIB_ENTRY_SRC_FLAG_ADDED);

    esrc->fes_flags |= (FIB_ENTRY_SRC_FLAG_ACTIVE |
                        FIB_ENTRY_SRC_FLAG_CONTRIBUTING);
    vft = fib_entry_src_get_vft(esrc);

    if (NULL != vft->fesv_activate)
    {
	houston_we_are_go_for_install = vft->fesv_activate(esrc, fib_entry);
    }
    else
    {
	/*
	 * the source is not providing an activate function, we'll assume
	 * therefore it has no objection to installing the entry
	 */
	houston_we_are_go_for_install = !0;
    }

    /*
     * link to the path-list provided by the source, and go check
     * if that forms any loops in the graph.
     */
    fib_entry->fe_parent = esrc->fes_pl;
    fib_entry->fe_sibling =
	fib_path_list_child_add(fib_entry->fe_parent,
				FIB_NODE_TYPE_ENTRY,
				fib_entry_get_index(fib_entry));

    fib_entry_recursive_loop_detect_i(fib_entry->fe_parent);

    FIB_ENTRY_DBG(fib_entry, "activate: %d",
		  fib_entry->fe_parent);

    /*
     * If this source should push its state to covered prefixs, do that now.
     */
    fib_entry_src_covered_inherit_add(fib_entry, source);

    if (0 != houston_we_are_go_for_install)
    {
	fib_entry_src_action_install(fib_entry, source);
    }
    else
    {
	fib_entry_src_action_uninstall(fib_entry);
    }
}

void
fib_entry_src_action_deactivate (fib_entry_t *fib_entry,
				 fib_source_t source)

{
    fib_node_index_t path_list_index;
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find(fib_entry, source);

    ASSERT(esrc->fes_flags & FIB_ENTRY_SRC_FLAG_ACTIVE);

    FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_deactivate,
                             (esrc, fib_entry));

    esrc->fes_flags &= ~(FIB_ENTRY_SRC_FLAG_ACTIVE |
                         FIB_ENTRY_SRC_FLAG_CONTRIBUTING);

    FIB_ENTRY_DBG(fib_entry, "deactivate: %d", fib_entry->fe_parent);

    /*
     * If this source should pull its state from covered prefixs, do that now.
     * If this source also has the INHERITED flag set then it has a cover
     * that wants to push down forwarding. We only want the covereds to see
     * one update.
     */
    fib_entry_src_covered_inherit_remove(fib_entry, esrc);

    /*
     * un-link from an old path-list. Check for any loops this will clear
     */
    path_list_index = fib_entry->fe_parent;
    fib_entry->fe_parent = FIB_NODE_INDEX_INVALID;

    fib_entry_recursive_loop_detect_i(path_list_index);

    /*
     * this will unlock the path-list, so it may be invalid thereafter.
     */
    fib_path_list_child_remove(path_list_index, fib_entry->fe_sibling);
    fib_entry->fe_sibling = FIB_NODE_INDEX_INVALID;
}

static void
fib_entry_src_action_fwd_update (const fib_entry_t *fib_entry,
				 fib_source_t source)
{
    fib_entry_src_t *esrc;

    vec_foreach(esrc, fib_entry->fe_srcs)
    {
	FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_fwd_update,
                                 (esrc, fib_entry, source));
    }
}

void
fib_entry_src_action_reactivate (fib_entry_t *fib_entry,
				 fib_source_t source)
{
    fib_node_index_t path_list_index;
    const fib_entry_src_vft_t *vft;
    fib_entry_src_t *esrc;
    int remain_installed;

    esrc = fib_entry_src_find(fib_entry, source);

    ASSERT(esrc->fes_flags & FIB_ENTRY_SRC_FLAG_ACTIVE);

    FIB_ENTRY_DBG(fib_entry, "reactivate: %d to %d",
		  fib_entry->fe_parent,
		  esrc->fes_pl);

    /*
     * call the source to reactive and get the go/no-go to remain installed
     */
    vft = fib_entry_src_get_vft(esrc);

    if (NULL != vft->fesv_reactivate)
    {
        remain_installed = vft->fesv_reactivate(esrc, fib_entry);
    }
    else
    {
        remain_installed = 1;
    }

    if (fib_entry->fe_parent != esrc->fes_pl)
    {
	/*
	 * un-link from an old path-list. Check for any loops this will clear
	 */
	path_list_index = fib_entry->fe_parent;
	fib_entry->fe_parent = FIB_NODE_INDEX_INVALID;

	/*
	 * temporary lock so it doesn't get deleted when this entry is no
	 * longer a child.
	 */
	fib_path_list_lock(path_list_index);

	/*
	 * this entry is no longer a child. after unlinking check if any loops
	 * were broken
	 */
	fib_path_list_child_remove(path_list_index,
				   fib_entry->fe_sibling);

	fib_entry_recursive_loop_detect_i(path_list_index);

	/*
	 * link to the path-list provided by the source, and go check
	 * if that forms any loops in the graph.
	 */
	fib_entry->fe_parent = esrc->fes_pl;
	fib_entry->fe_sibling =
	    fib_path_list_child_add(fib_entry->fe_parent,
				    FIB_NODE_TYPE_ENTRY,
				    fib_entry_get_index(fib_entry));

	fib_entry_recursive_loop_detect_i(fib_entry->fe_parent);
	fib_path_list_unlock(path_list_index);

        /*
         * If this source should push its state to covered prefixs, do that now.
         */
        fib_entry_src_covered_inherit_add(fib_entry, source);
    }

    if (!remain_installed)
    {
        fib_entry_src_action_uninstall(fib_entry);
    }
    else
    {
        fib_entry_src_action_install(fib_entry, source);
    }
    fib_entry_src_action_fwd_update(fib_entry, source);
}

void
fib_entry_src_action_installed (const fib_entry_t *fib_entry,
				fib_source_t source)
{
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find(fib_entry, source);

    FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_installed,
                             (esrc, fib_entry));

    fib_entry_src_action_fwd_update(fib_entry, source);
}

/*
 * fib_entry_src_action_add
 *
 * Adding a source can result in a new fib_entry being created, which
 * can inturn mean the pool is realloc'd and thus the entry passed as
 * an argument it also realloc'd
 * @return the original entry
 */
fib_entry_t *
fib_entry_src_action_add (fib_entry_t *fib_entry,
			  fib_source_t source,
			  fib_entry_flag_t flags,
			  const dpo_id_t *dpo)
{
    fib_node_index_t fib_entry_index;
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find_or_create(fib_entry, source, flags);

    ASSERT(esrc->fes_ref_count < 255);
    esrc->fes_ref_count++;

    if (flags != esrc->fes_entry_flags)
    {
        FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_flags_change,
                                 (esrc, fib_entry, flags));
    }
    esrc->fes_entry_flags = flags;

    if (1 != esrc->fes_ref_count)
    {
        /*
         * we only want to add the source on the 0->1 transition
         */
        return (fib_entry);
    }

    /*
     * save variable so we can recover from a fib_entry realloc.
     */
    fib_entry_index = fib_entry_get_index(fib_entry);

    FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_add,
                             (esrc,
                              fib_entry,
                              flags,
                              fib_entry_get_dpo_proto(fib_entry),
                              dpo));

    fib_entry = fib_entry_get(fib_entry_index);

    esrc->fes_flags |= FIB_ENTRY_SRC_FLAG_ADDED;

    fib_path_list_lock(esrc->fes_pl);

    /*
     * the source owns a lock on the entry
     */
    fib_entry_lock(fib_entry_get_index(fib_entry));

    return (fib_entry);
}

/*
 * fib_entry_src_action_update
 *
 * Adding a source can result in a new fib_entry being created, which
 * can inturn mean the pool is realloc'd and thus the entry passed as
 * an argument it also realloc'd
 * @return the original entry
 */
fib_entry_t *
fib_entry_src_action_update (fib_entry_t *fib_entry,
			     fib_source_t source,
			     fib_entry_flag_t flags,
			     const dpo_id_t *dpo)
{
    fib_node_index_t fib_entry_index, old_path_list_index;
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find_or_create(fib_entry, source, flags);

    if (NULL == esrc)
    {
	return (fib_entry_src_action_add(fib_entry, source, flags, dpo));
    }

    old_path_list_index = esrc->fes_pl;
    esrc->fes_entry_flags = flags;

    /*
     * save variable so we can recover from a fib_entry realloc.
     */
    fib_entry_index = fib_entry_get_index(fib_entry);

    FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_add,
                             (esrc,
                              fib_entry,
                              flags,
                              fib_entry_get_dpo_proto(fib_entry),
                              dpo));

    fib_entry = fib_entry_get(fib_entry_index);

    esrc->fes_flags |= FIB_ENTRY_SRC_FLAG_ADDED;

    fib_path_list_lock(esrc->fes_pl);
    fib_path_list_unlock(old_path_list_index);

    return (fib_entry);
}

fib_entry_src_flag_t
fib_entry_src_action_remove_or_update_inherit (fib_entry_t *fib_entry,
                                               fib_source_t source)
{
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find(fib_entry, source);

    if (NULL == esrc)
        return (FIB_ENTRY_SRC_FLAG_ACTIVE);

    if ((esrc->fes_entry_flags & FIB_ENTRY_FLAG_COVERED_INHERIT) &&
        (esrc->fes_flags & FIB_ENTRY_SRC_FLAG_INHERITED))
    {
        fib_entry_src_t *cover_src;
        fib_node_index_t coveri;
        fib_entry_t *cover;

        /*
         * this source was pushing inherited state, but so is its
         * cover. Now that this source is going away, we need to
         * pull the covers forwarding and use it to update the covereds.
         * Go grab the path-list from the cover, rather than start a walk from
         * the cover, so we don't recursively update this entry.
         */
        coveri = fib_table_get_less_specific(fib_entry->fe_fib_index,
                                             &fib_entry->fe_prefix);

        /*
         * only the default route has itself as its own cover, but the
         * default route cannot have inherited from something else.
         */
        ASSERT(coveri != fib_entry_get_index(fib_entry));

        cover = fib_entry_get(coveri);
        cover_src = fib_entry_src_find(cover, source);

        ASSERT(NULL != cover_src);

        esrc = fib_entry_src_action_update_from_cover(fib_entry, cover_src);
        esrc->fes_entry_flags &= ~FIB_ENTRY_FLAG_COVERED_INHERIT;

        /*
         * Now push the new state from the cover down to the covereds
         */
        fib_entry_src_covered_inherit_add(fib_entry, source);

        return (esrc->fes_flags);
    }
    else
    {
        return (fib_entry_src_action_remove(fib_entry, source));
    }
}

fib_entry_src_flag_t
fib_entry_src_action_remove (fib_entry_t *fib_entry,
			     fib_source_t source)

{
    fib_node_index_t old_path_list;
    fib_entry_src_flag_t sflags;
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find(fib_entry, source);

    if (NULL == esrc)
	return (FIB_ENTRY_SRC_FLAG_ACTIVE);

    esrc->fes_ref_count--;
    sflags = esrc->fes_flags;

    if (0 != esrc->fes_ref_count)
    {
        /*
         * only remove the source on the 1->0 transisition
         */
        return (sflags);
    }

    if (esrc->fes_flags & FIB_ENTRY_SRC_FLAG_ACTIVE)
    {
        fib_entry_src_action_deactivate(fib_entry, source);
    }
    else if (esrc->fes_flags & FIB_ENTRY_SRC_FLAG_CONTRIBUTING)
    {
        FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_deactivate,
                                 (esrc, fib_entry));
        esrc->fes_flags &= ~FIB_ENTRY_SRC_FLAG_CONTRIBUTING;
    }

    old_path_list = esrc->fes_pl;

    FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_remove, (esrc));

    fib_path_list_unlock(old_path_list);
    fib_entry_unlock(fib_entry_get_index(fib_entry));

    sflags &= ~FIB_ENTRY_SRC_FLAG_ADDED;
    fib_entry_src_action_deinit(fib_entry, source);

    return (sflags);
}

/*
 * fib_route_attached_cross_table
 *
 * Return true the the route is attached via an interface that
 * is not in the same table as the route
 */
static inline int
fib_route_attached_cross_table (const fib_entry_t *fib_entry,
				const fib_route_path_t *rpath)
{
    /*
     * - All zeros next-hop
     * - a valid interface
     * - entry's fib index not equeal to interface's index
     */
    if (ip46_address_is_zero(&rpath->frp_addr) &&
	(~0 != rpath->frp_sw_if_index) &&
        !(rpath->frp_flags & FIB_ROUTE_PATH_DVR) &&
	(fib_entry->fe_fib_index != 
	 fib_table_get_index_for_sw_if_index(fib_entry_get_proto(fib_entry),
					     rpath->frp_sw_if_index)))
    {
	return (!0);
    }
    return (0);
}

/*
 * Return true if the path is attached
 */
static inline int
fib_path_is_attached (const fib_route_path_t *rpath)
{
    /*
     * DVR paths are not attached, since we are not playing the
     * L3 game with these
     */
    if (rpath->frp_flags & FIB_ROUTE_PATH_DVR)
    {
        return (0);
    }

    /*
     * - All zeros next-hop
     * - a valid interface
     */
    if (ip46_address_is_zero(&rpath->frp_addr) &&
	(~0 != rpath->frp_sw_if_index))
    {
	return (!0);
    }
    else if (rpath->frp_flags & FIB_ROUTE_PATH_ATTACHED)
    {
        return (!0);
    }
    return (0);
}

fib_path_list_flags_t
fib_entry_src_flags_2_path_list_flags (fib_entry_flag_t eflags)
{
    fib_path_list_flags_t plf = FIB_PATH_LIST_FLAG_NONE;

    if (eflags & FIB_ENTRY_FLAG_DROP)
    {
	plf |= FIB_PATH_LIST_FLAG_DROP;
    }
    if (eflags & FIB_ENTRY_FLAG_EXCLUSIVE)
    {
	plf |= FIB_PATH_LIST_FLAG_EXCLUSIVE;
    }
    if (eflags & FIB_ENTRY_FLAG_LOCAL)
    {
	plf |= FIB_PATH_LIST_FLAG_LOCAL;
    }

    return (plf);
}

static void
fib_entry_flags_update (const fib_entry_t *fib_entry,
			const fib_route_path_t *rpath,
			fib_path_list_flags_t *pl_flags,
			fib_entry_src_t *esrc)
{
    if ((esrc->fes_src == FIB_SOURCE_API) ||
	(esrc->fes_src == FIB_SOURCE_CLI))
    {
	if (fib_path_is_attached(rpath))
	{
	    esrc->fes_entry_flags |= FIB_ENTRY_FLAG_ATTACHED;
	}
	else
	{
	    esrc->fes_entry_flags &= ~FIB_ENTRY_FLAG_ATTACHED;
	}
	if (rpath->frp_flags & FIB_ROUTE_PATH_DEAG)
	{
	    esrc->fes_entry_flags |= FIB_ENTRY_FLAG_LOOSE_URPF_EXEMPT;
	}
    }
    if (fib_route_attached_cross_table(fib_entry, rpath) &&
        !(esrc->fes_entry_flags & FIB_ENTRY_FLAG_NO_ATTACHED_EXPORT))
    {
	esrc->fes_entry_flags |= FIB_ENTRY_FLAG_IMPORT;
    }
    else
    {
	esrc->fes_entry_flags &= ~FIB_ENTRY_FLAG_IMPORT;
    }
}

/*
 * fib_entry_src_action_add
 *
 * Adding a source can result in a new fib_entry being created, which
 * can inturn mean the pool is realloc'd and thus the entry passed as
 * an argument it also realloc'd
 * @return the entry
 */
fib_entry_t*
fib_entry_src_action_path_add (fib_entry_t *fib_entry,
			       fib_source_t source,
			       fib_entry_flag_t flags,
			       const fib_route_path_t *rpath)
{
    fib_node_index_t old_path_list, fib_entry_index;
    fib_path_list_flags_t pl_flags;
    fib_entry_src_t *esrc;

    /*
     * save variable so we can recover from a fib_entry realloc.
     */
    fib_entry_index = fib_entry_get_index(fib_entry);

    esrc = fib_entry_src_find(fib_entry, source);
    if (NULL == esrc)
    {
	fib_entry =
            fib_entry_src_action_add(fib_entry,
                                     source,
                                     flags,
                                     drop_dpo_get(
                                         fib_entry_get_dpo_proto(fib_entry)));
	esrc = fib_entry_src_find(fib_entry, source);
    }

    /*
     * we are no doubt modifying a path-list. If the path-list
     * is shared, and hence not modifiable, then the index returned
     * will be for a different path-list. This FIB entry to needs
     * to maintain its lock appropriately.
     */
    old_path_list = esrc->fes_pl;

    ASSERT(FIB_ENTRY_SRC_VFT_EXISTS(esrc, fesv_path_add));

    pl_flags = fib_entry_src_flags_2_path_list_flags(fib_entry_get_flags_i(fib_entry));
    fib_entry_flags_update(fib_entry, rpath, &pl_flags, esrc);

    FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_path_add,
                             (esrc, fib_entry, pl_flags, rpath));
    fib_entry = fib_entry_get(fib_entry_index);

    fib_path_list_lock(esrc->fes_pl);
    fib_path_list_unlock(old_path_list);

    return (fib_entry);
}

/*
 * fib_entry_src_action_swap
 *
 * The source is providing new paths to replace the old ones.
 * Adding a source can result in a new fib_entry being created, which
 * can inturn mean the pool is realloc'd and thus the entry passed as
 * an argument it also realloc'd
 * @return the entry
 */
fib_entry_t*
fib_entry_src_action_path_swap (fib_entry_t *fib_entry,
				fib_source_t source,
				fib_entry_flag_t flags,
				const fib_route_path_t *rpaths)
{
    fib_node_index_t old_path_list, fib_entry_index;
    fib_path_list_flags_t pl_flags;
    const fib_route_path_t *rpath;
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find(fib_entry, source);

    /*
     * save variable so we can recover from a fib_entry realloc.
     */
    fib_entry_index = fib_entry_get_index(fib_entry);

    if (NULL == esrc)
    {
        fib_entry = fib_entry_src_action_add(fib_entry,
					     source,
					     flags,
                                             drop_dpo_get(
                                                 fib_entry_get_dpo_proto(fib_entry)));
	esrc = fib_entry_src_find(fib_entry, source);
    }
    else
    {
        if (flags != esrc->fes_entry_flags)
        {
            FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_flags_change,
                                     (esrc, fib_entry, flags));
        }
        esrc->fes_entry_flags = flags;
    }

    /*
     * swapping paths may create a new path-list (or may use an existing shared)
     * but we are certainly getting a different one. This FIB entry to needs
     * to maintain its lock appropriately.
     */
    old_path_list = esrc->fes_pl;

    ASSERT(FIB_ENTRY_SRC_VFT_EXISTS(esrc, fesv_path_swap));

    pl_flags = fib_entry_src_flags_2_path_list_flags(flags);

    vec_foreach(rpath, rpaths)
    {
	fib_entry_flags_update(fib_entry, rpath, &pl_flags, esrc);
    }

    FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_path_swap,
                             (esrc, fib_entry,
                              pl_flags, rpaths));

    fib_entry = fib_entry_get(fib_entry_index);

    fib_path_list_lock(esrc->fes_pl);
    fib_path_list_unlock(old_path_list);

    return (fib_entry);
}

fib_entry_src_flag_t
fib_entry_src_action_path_remove (fib_entry_t *fib_entry,
				  fib_source_t source,
				  const fib_route_path_t *rpath)
{
    fib_path_list_flags_t pl_flags;
    fib_node_index_t old_path_list;
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find(fib_entry, source);

    ASSERT(NULL != esrc);
    ASSERT(esrc->fes_flags & FIB_ENTRY_SRC_FLAG_ADDED);

    /*
     * we no doubt modifying a path-list. If the path-list
     * is shared, and hence not modifiable, then the index returned
     * will be for a different path-list. This FIB entry to needs
     * to maintain its lock appropriately.
     */
    old_path_list = esrc->fes_pl;

    ASSERT(FIB_ENTRY_SRC_VFT_EXISTS(esrc, fesv_path_remove));

    pl_flags = fib_entry_src_flags_2_path_list_flags(fib_entry_get_flags_i(fib_entry));
    fib_entry_flags_update(fib_entry, rpath, &pl_flags, esrc);

    FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_path_remove,
                             (esrc, pl_flags, rpath));

    /*
     * lock the new path-list, unlock the old if it had one
     */
    fib_path_list_unlock(old_path_list);

    if (FIB_NODE_INDEX_INVALID != esrc->fes_pl) {
	fib_path_list_lock(esrc->fes_pl);
	return (FIB_ENTRY_SRC_FLAG_ADDED);
    }
    else
    {
	/*
	 * no more paths left from this source
	 */
	fib_entry_src_action_remove_or_update_inherit(fib_entry, source);
	return (FIB_ENTRY_SRC_FLAG_NONE);
    }
}

u8*
fib_entry_src_format (fib_entry_t *fib_entry,
		      fib_source_t source,
		      u8* s)
{
    fib_entry_src_t *esrc;

    esrc = fib_entry_src_find(fib_entry, source);

    FIB_ENTRY_SRC_VFT_INVOKE_AND_RETURN(esrc, fesv_format, (esrc, s));

    return (s);
}

adj_index_t
fib_entry_get_adj_for_source (fib_node_index_t fib_entry_index,
			      fib_source_t source)
{
    fib_entry_t *fib_entry;
    fib_entry_src_t *esrc;

    if (FIB_NODE_INDEX_INVALID == fib_entry_index)
	return (ADJ_INDEX_INVALID);

    fib_entry = fib_entry_get(fib_entry_index);
    esrc = fib_entry_src_find(fib_entry, source);

    if (NULL != esrc)
    {
	if (FIB_NODE_INDEX_INVALID != esrc->fes_pl)
	{
	    return (fib_path_list_get_adj(
			esrc->fes_pl,
			fib_entry_get_default_chain_type(fib_entry)));
	}
    }
    return (ADJ_INDEX_INVALID);
}

const int
fib_entry_get_dpo_for_source (fib_node_index_t fib_entry_index,
			      fib_source_t source,
			      dpo_id_t *dpo)
{
    fib_entry_t *fib_entry;
    fib_entry_src_t *esrc;

    if (FIB_NODE_INDEX_INVALID == fib_entry_index)
	return (0);

    fib_entry = fib_entry_get(fib_entry_index);
    esrc = fib_entry_src_find(fib_entry, source);

    if (NULL != esrc)
    {
	if (FIB_NODE_INDEX_INVALID != esrc->fes_pl)
	{
	    fib_path_list_contribute_forwarding(
		esrc->fes_pl,
		fib_entry_get_default_chain_type(fib_entry),
                FIB_PATH_LIST_FWD_FLAG_NONE,
		dpo);

	    return (dpo_id_is_valid(dpo));
	}
    }
    return (0);
}

u32
fib_entry_get_resolving_interface_for_source (fib_node_index_t entry_index,
					      fib_source_t source)
{
    fib_entry_t *fib_entry;
    fib_entry_src_t *esrc;

    fib_entry = fib_entry_get(entry_index);

    esrc = fib_entry_src_find(fib_entry, source);

    if (NULL != esrc)
    {
	if (FIB_NODE_INDEX_INVALID != esrc->fes_pl)
	{
	    return (fib_path_list_get_resolving_interface(esrc->fes_pl));
	}
    }
    return (~0);
}

fib_entry_flag_t
fib_entry_get_flags_for_source (fib_node_index_t entry_index,
				fib_source_t source)
{
    fib_entry_t *fib_entry;
    fib_entry_src_t *esrc;

    fib_entry = fib_entry_get(entry_index);

    esrc = fib_entry_src_find(fib_entry, source);

    if (NULL != esrc)
    {
	return (esrc->fes_entry_flags);
    }

    return (FIB_ENTRY_FLAG_NONE);
}

fib_entry_flag_t
fib_entry_get_flags_i (const fib_entry_t *fib_entry)
{
    fib_entry_flag_t flags;

    /*
     * the vector of sources is deliberately arranged in priority order
     */
    if (0 == vec_len(fib_entry->fe_srcs))
    {
	flags = FIB_ENTRY_FLAG_NONE;
    }
    else
    {
	fib_entry_src_t *esrc;

	esrc = vec_elt_at_index(fib_entry->fe_srcs, 0);
	flags = esrc->fes_entry_flags;
    }

    return (flags);
}

void
fib_entry_set_source_data (fib_node_index_t fib_entry_index,
                           fib_source_t source,
                           const void *data)
{
    fib_entry_t *fib_entry;
    fib_entry_src_t *esrc;

    fib_entry = fib_entry_get(fib_entry_index);
    esrc = fib_entry_src_find(fib_entry, source);

    if (NULL != esrc)
    {
        FIB_ENTRY_SRC_VFT_INVOKE(esrc, fesv_set_data,
                                 (esrc, fib_entry, data));
    }
}

const void*
fib_entry_get_source_data (fib_node_index_t fib_entry_index,
                           fib_source_t source)
{
    fib_entry_t *fib_entry;
    fib_entry_src_t *esrc;

    fib_entry = fib_entry_get(fib_entry_index);
    esrc = fib_entry_src_find(fib_entry, source);

    if (NULL != esrc)
    {
        FIB_ENTRY_SRC_VFT_INVOKE_AND_RETURN(esrc, fesv_get_data,
                                            (esrc, fib_entry));
    }
    return (NULL);
}

void
fib_entry_src_module_init (void)
{
    fib_entry_src_rr_register();
    fib_entry_src_interface_register();
    fib_entry_src_interpose_register();
    fib_entry_src_default_route_register();
    fib_entry_src_special_register();
    fib_entry_src_api_register();
    fib_entry_src_adj_register();
    fib_entry_src_mpls_register();
    fib_entry_src_lisp_register();
}