2 * Copyright (c) 2016 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
16 #include <vlib/vlib.h>
17 #include <vnet/ip/format.h>
18 #include <vnet/ip/lookup.h>
19 #include <vnet/adj/adj.h>
20 #include <vnet/dpo/drop_dpo.h>
22 #include "fib_entry_src.h"
23 #include "fib_entry_cover.h"
24 #include "fib_entry.h"
25 #include "fib_table.h"
28 * fib_entry_src_rr_resolve_via_connected
30 * Resolve via a connected cover.
33 fib_entry_src_rr_resolve_via_connected (fib_entry_src_t *src,
34 const fib_entry_t *fib_entry,
35 const fib_entry_t *cover)
37 const fib_route_path_t path = {
38 .frp_proto = fib_entry->fe_prefix.fp_proto,
39 .frp_addr = fib_entry->fe_prefix.fp_addr,
40 .frp_sw_if_index = fib_entry_get_resolving_interface(
41 fib_entry_get_index(cover)),
45 fib_route_path_t *paths = NULL;
46 vec_add1(paths, path);
49 * since the cover is connected, the address this entry corresponds
50 * to is a peer (ARP-able for) on the interface to which the cover is
51 * connected. The fact we resolve via the cover, just means this RR
52 * source is the first SRC to use said peer. The ARP source will be along
53 * shortly to over-rule this RR source.
55 src->fes_pl = fib_path_list_create(FIB_PATH_LIST_FLAG_NONE, paths);
56 src->fes_entry_flags = fib_entry_get_flags(fib_entry_get_index(cover));
63 * Source initialisation Function
66 fib_entry_src_rr_init (fib_entry_src_t *src)
68 src->rr.fesr_cover = FIB_NODE_INDEX_INVALID;
69 src->rr.fesr_sibling = FIB_NODE_INDEX_INVALID;
73 * Source activation. Called when the source is the new best source on the entry
76 fib_entry_src_rr_activate (fib_entry_src_t *src,
77 const fib_entry_t *fib_entry)
82 * find the covering prefix. become a dependent thereof.
83 * for IP there should always be a cover, though it may be the default route.
84 * For MPLS there is never a cover.
86 if (FIB_PROTOCOL_MPLS == fib_entry->fe_prefix.fp_proto)
88 src->fes_pl = fib_path_list_create_special(FIB_PROTOCOL_MPLS,
89 FIB_PATH_LIST_FLAG_DROP,
91 fib_path_list_lock(src->fes_pl);
95 src->rr.fesr_cover = fib_table_get_less_specific(fib_entry->fe_fib_index,
96 &fib_entry->fe_prefix);
98 ASSERT(FIB_NODE_INDEX_INVALID != src->rr.fesr_cover);
100 cover = fib_entry_get(src->rr.fesr_cover);
102 src->rr.fesr_sibling =
103 fib_entry_cover_track(cover, fib_entry_get_index(fib_entry));
106 * if the ocver is attached then install an attached-host path
107 * (like an adj-fib). Otherwise inherit the forwarding from the cover
109 if (FIB_ENTRY_FLAG_ATTACHED & fib_entry_get_flags_i(cover))
111 fib_entry_src_rr_resolve_via_connected(src, fib_entry, cover);
116 * use the path-list of the cover, unless it would form a loop.
117 * that is unless the cover is via this entry.
118 * If a loop were to form it would be a 1 level loop (i.e. X via X),
119 * and there would be 2 locks on the path-list; one since its used
120 * by the cover, and 1 from here. The first lock will go when the
121 * cover is removed, the second, and last, when the covered walk
122 * occurs during the cover's removel - this is not a place where
123 * we can handle last lock gone.
124 * In short, don't let the loop form. The usual rules of 'we must
125 * let it form so we know when it breaks' don't apply here, since
126 * the loop will break when the cover changes, and this function
127 * will be called again when that happens.
129 fib_node_index_t *entries = NULL;
130 fib_protocol_t proto;
132 proto = fib_entry->fe_prefix.fp_proto;
133 vec_add1(entries, fib_entry_get_index(fib_entry));
135 if (fib_path_list_recursive_loop_detect(cover->fe_parent,
138 src->fes_pl = fib_path_list_create_special(
140 FIB_PATH_LIST_FLAG_DROP,
141 drop_dpo_get(fib_proto_to_dpo(proto)));
145 src->fes_pl = cover->fe_parent;
150 fib_path_list_lock(src->fes_pl);
153 * return go for install
160 * Called when the source is no longer best source on the entry
163 fib_entry_src_rr_deactivate (fib_entry_src_t *src,
164 const fib_entry_t *fib_entry)
169 * remove the depednecy on the covering entry
171 if (FIB_NODE_INDEX_INVALID != src->rr.fesr_cover)
173 cover = fib_entry_get(src->rr.fesr_cover);
174 fib_entry_cover_untrack(cover, src->rr.fesr_sibling);
175 src->rr.fesr_cover = FIB_NODE_INDEX_INVALID;
178 fib_path_list_unlock(src->fes_pl);
179 src->fes_pl = FIB_NODE_INDEX_INVALID;
180 src->fes_entry_flags = FIB_ENTRY_FLAG_NONE;
183 static fib_entry_src_cover_res_t
184 fib_entry_src_rr_cover_change (fib_entry_src_t *src,
185 const fib_entry_t *fib_entry)
187 fib_entry_src_cover_res_t res = {
189 .bw_reason = FIB_NODE_BW_REASON_FLAG_NONE,
192 if (FIB_NODE_INDEX_INVALID == src->rr.fesr_cover)
195 * the source may be added, but it is not active
196 * if it is not tracking the cover.
202 * this function is called when this entry's cover has a more specific
203 * entry inserted benaeth it. That does not necessarily mean that this
204 * entry is covered by the new prefix. check that
206 if (src->rr.fesr_cover != fib_table_get_less_specific(fib_entry->fe_fib_index,
207 &fib_entry->fe_prefix))
209 fib_entry_src_rr_deactivate(src, fib_entry);
210 fib_entry_src_rr_activate(src, fib_entry);
213 * dependent children need to re-resolve to the new forwarding info
215 res.bw_reason = FIB_NODE_BW_REASON_FLAG_EVALUATE;
221 * fib_entry_src_rr_cover_update
223 * This entry's cover has updated its forwarding info. This entry
224 * will need to re-inheret.
226 static fib_entry_src_cover_res_t
227 fib_entry_src_rr_cover_update (fib_entry_src_t *src,
228 const fib_entry_t *fib_entry)
230 fib_entry_src_cover_res_t res = {
232 .bw_reason = FIB_NODE_BW_REASON_FLAG_NONE,
234 fib_node_index_t old_path_list;
237 if (FIB_NODE_INDEX_INVALID == src->rr.fesr_cover)
240 * the source may be added, but it is not active
241 * if it is not tracking the cover.
246 cover = fib_entry_get(src->rr.fesr_cover);
247 old_path_list = src->fes_pl;
250 * if the ocver is attached then install an attached-host path
251 * (like an adj-fib). Otherwise inherit the forwarding from the cover
253 if (FIB_ENTRY_FLAG_ATTACHED & fib_entry_get_flags_i(cover))
255 fib_entry_src_rr_resolve_via_connected(src, fib_entry, cover);
259 src->fes_pl = cover->fe_parent;
261 fib_path_list_lock(src->fes_pl);
262 fib_path_list_unlock(old_path_list);
265 * dependent children need to re-resolve to the new forwarding info
267 res.bw_reason = FIB_NODE_BW_REASON_FLAG_EVALUATE;
273 fib_entry_src_rr_format (fib_entry_src_t *src,
276 return (format(s, "cover:%d", src->rr.fesr_cover));
279 const static fib_entry_src_vft_t rr_src_vft = {
280 .fesv_init = fib_entry_src_rr_init,
281 .fesv_activate = fib_entry_src_rr_activate,
282 .fesv_deactivate = fib_entry_src_rr_deactivate,
283 .fesv_cover_change = fib_entry_src_rr_cover_change,
284 .fesv_cover_update = fib_entry_src_rr_cover_update,
285 .fesv_format = fib_entry_src_rr_format,
289 fib_entry_src_rr_register (void)
291 fib_entry_src_register(FIB_SOURCE_RR, &rr_src_vft);
292 fib_entry_src_register(FIB_SOURCE_URPF_EXEMPT, &rr_src_vft);