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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 <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"),
};
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