aboutsummaryrefslogtreecommitdiffstats
path: root/src/vnet/fib/fib_bfd.c
blob: 6bfd29ae2cce4c47a9583a3059a9ecfdfa97513f (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
/*
 * 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/bfd/bfd_main.h>

#include <vnet/fib/fib_entry_delegate.h>
#include <vnet/fib/fib_entry.h>
#include <vnet/fib/fib_table.h>
#include <vnet/fib/fib_walk.h>

static fib_bfd_state_t
fib_bfd_bfd_state_to_fib (bfd_state_e bstate)
{
    switch (bstate)
    {
    case BFD_STATE_up:
        return (FIB_BFD_STATE_UP);
    case BFD_STATE_down:
    case BFD_STATE_admin_down:
    case BFD_STATE_init:
        return (FIB_BFD_STATE_DOWN);
    }
    return (FIB_BFD_STATE_DOWN);
}

static void
fib_bfd_update_walk (fib_node_index_t fei)
{
    /*
     * initiate a backwalk of dependent children
     * to notify of the state change of this entry.
     */
    fib_node_back_walk_ctx_t ctx = {
        .fnbw_reason = FIB_NODE_BW_REASON_FLAG_EVALUATE,
    };
    fib_walk_sync(FIB_NODE_TYPE_ENTRY, fei, &ctx);
}

/**
 * @brief Callback function registered with BFD module to receive notifications
 * of the CRUD of BFD sessions
 * would be static but for the fact it's called from the unit-tests
 */
void
fib_bfd_notify (bfd_listen_event_e event,
                const bfd_session_t *session)
{
    fib_entry_delegate_t *fed;
    const bfd_udp_key_t *key;
    fib_node_index_t fei;

    if (BFD_HOP_TYPE_MULTI != session->hop_type)
    {
        /*
         * multi-hop BFD sessions attach directly to the FIB entry
         * single-hop adj to the associate adjacency.
         */
        return;
    }

    key = &session->udp.key;

    fib_prefix_t pfx = {
        .fp_addr = key->peer_addr,
        .fp_proto = (ip46_address_is_ip4 (&key->peer_addr) ?
                     FIB_PROTOCOL_IP4:
                     FIB_PROTOCOL_IP6),
        .fp_len = (ip46_address_is_ip4 (&key->peer_addr) ?
                   32:
                   128),
    };

    /*
     * get the FIB entry
     */
    fei = fib_table_lookup_exact_match(key->fib_index, &pfx);

    switch (event)
    {
    case BFD_LISTEN_EVENT_CREATE:
        /*
         * The creation of a new session
         */
        if ((FIB_NODE_INDEX_INVALID != fei) &&
            (fed = fib_entry_delegate_find(fib_entry_get(fei),
                                           FIB_ENTRY_DELEGATE_BFD)))
        {
            /*
             * already got state for this entry
             */
        }
        else
        {
            /*
             * source and lock the entry. add the delegate
             */
            fei = fib_table_entry_special_add(key->fib_index,
                                              &pfx,
                                              FIB_SOURCE_RR,
                                              FIB_ENTRY_FLAG_NONE);
            fib_entry_lock(fei);

            fed = fib_entry_delegate_find_or_add(fib_entry_get(fei),
                                                 FIB_ENTRY_DELEGATE_BFD);

            /*
             * pretend the session is up and skip the walk.
             * If we set it down then we get traffic loss on new children.
             * if we walk then we lose traffic for existing children. Wait
             * for the first BFD UP/DOWN before we let the session's state
             * influence forwarding.
             */
            fed->fd_bfd_state = FIB_BFD_STATE_UP;
        }
        break;

    case BFD_LISTEN_EVENT_UPDATE:
        /*
         * state change up/dowm and
         */
        ASSERT(FIB_NODE_INDEX_INVALID != fei);

        fed = fib_entry_delegate_find(fib_entry_get(fei),
                                      FIB_ENTRY_DELEGATE_BFD);

        if (NULL != fed)
        {
            fed->fd_bfd_state = fib_bfd_bfd_state_to_fib(session->local_state);
            fib_bfd_update_walk(fei);
        }
        /*
         * else
         *   no BFD state
         */
        break;

    case BFD_LISTEN_EVENT_DELETE:
        /*
         * session has been removed.
         */
        if (FIB_NODE_INDEX_INVALID == fei)
        {
            /*
             * no FIB entry
             */
        }
        else if (fib_entry_delegate_find(fib_entry_get(fei),
                                         FIB_ENTRY_DELEGATE_BFD))
        {
            /*
             * has an associated BFD tracking delegate
             * usource the entry and remove the BFD tracking delegate
             */
            fib_entry_delegate_remove(fib_entry_get(fei),
                                      FIB_ENTRY_DELEGATE_BFD);
            fib_bfd_update_walk(fei);

            fib_table_entry_special_remove(key->fib_index,
                                           &pfx,
                                           FIB_SOURCE_RR);
            fib_entry_unlock(fei);
        }
        /*
         * else
         * no BFD associated state
         */
        break;
    }
}

static clib_error_t *
fib_bfd_main_init (vlib_main_t * vm)
{
    bfd_register_listener(fib_bfd_notify);

    return (NULL);
}

VLIB_INIT_FUNCTION (fib_bfd_main_init) =
{
    .runs_after = VLIB_INITS("bfd_main_init"),
};