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authorNeale Ranns <nranns@cisco.com>2017-04-05 08:11:14 -0700
committerDamjan Marion <dmarion.lists@gmail.com>2017-04-06 15:18:44 +0000
commit88fc83eb716bf07f4634de6de5b569f795a56418 (patch)
tree4c8037b62cb6a57209aef4e28ae273d0ba4e40e7 /src/vnet/adj/adj_bfd.c
parent5ee51f8ed616f14f3b32ae8857d383fefa02d861 (diff)
BFD-FIB interactions
- single-hop BFD: attach a delegate to the appropriate adjacency - multi-hop BFD [not supported yet]: attach a delegate to the FIB entry. adjacency/fib_entry state tracks the BFD session state. when the state is down the object does not contribute forwarding hence and hence dependent objects will not use it. For example, if a route is ECMP via two adjacencies and one of them is BFD down, then only the other is used to forward (i.e. we don't drop half the traffic). Change-Id: I0ef53e20e73b067001a132cd0a3045408811a822 Signed-off-by: Neale Ranns <nranns@cisco.com>
Diffstat (limited to 'src/vnet/adj/adj_bfd.c')
-rw-r--r--src/vnet/adj/adj_bfd.c184
1 files changed, 184 insertions, 0 deletions
diff --git a/src/vnet/adj/adj_bfd.c b/src/vnet/adj/adj_bfd.c
new file mode 100644
index 00000000000..3d294c4646e
--- /dev/null
+++ b/src/vnet/adj/adj_bfd.c
@@ -0,0 +1,184 @@
+/*
+ * 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/adj/adj_delegate.h>
+#include <vnet/adj/adj_nbr.h>
+#include <vnet/fib/fib_walk.h>
+
+static adj_bfd_state_t
+adj_bfd_bfd_state_to_fib (bfd_state_e bstate)
+{
+ switch (bstate)
+ {
+ case BFD_STATE_up:
+ return (ADJ_BFD_STATE_UP);
+ case BFD_STATE_down:
+ case BFD_STATE_admin_down:
+ case BFD_STATE_init:
+ return (ADJ_BFD_STATE_DOWN);
+ }
+ return (ADJ_BFD_STATE_DOWN);
+}
+
+static void
+adj_bfd_update_walk (adj_index_t ai)
+{
+ /*
+ * initiate a backwalk of dependent children
+ * to notify of the state change of this adj.
+ */
+ fib_node_back_walk_ctx_t ctx = {
+ .fnbw_reason = FIB_NODE_BW_REASON_FLAG_ADJ_UPDATE,
+ };
+ fib_walk_sync(FIB_NODE_TYPE_ADJ, ai, &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
+adj_bfd_notify (bfd_listen_event_e event,
+ const bfd_session_t *session)
+{
+ const bfd_udp_key_t *key;
+ fib_protocol_t fproto;
+ adj_delegate_t *aed;
+ adj_index_t ai;
+
+ if (BFD_HOP_TYPE_SINGLE != 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;
+
+ fproto = (ip46_address_is_ip4 (&key->peer_addr) ?
+ FIB_PROTOCOL_IP4:
+ FIB_PROTOCOL_IP6);
+
+ /*
+ * find the adj that corresponds to the BFD session.
+ */
+ ai = adj_nbr_add_or_lock(fproto,
+ fib_proto_to_link(fproto),
+ &key->peer_addr,
+ key->sw_if_index);
+
+ switch (event)
+ {
+ case BFD_LISTEN_EVENT_CREATE:
+ /*
+ * The creation of a new session
+ */
+ if ((ADJ_INDEX_INVALID != ai) &&
+ (aed = adj_delegate_get(adj_get(ai),
+ ADJ_DELEGATE_BFD)))
+ {
+ /*
+ * already got state for this adj
+ */
+ }
+ else
+ {
+ /*
+ * lock the adj. add the delegate.
+ * Lockinging the adj prevents it being removed and thus maintains
+ * the BFD derived states
+ */
+ adj_lock(ai);
+
+ aed = adj_delegate_find_or_add(adj_get(ai), ADJ_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.
+ */
+ aed->ad_bfd_state = ADJ_BFD_STATE_UP;
+ aed->ad_bfd_index = session->bs_idx;
+ }
+ break;
+
+ case BFD_LISTEN_EVENT_UPDATE:
+ /*
+ * state change up/dowm and
+ */
+ aed = adj_delegate_get(adj_get(ai), ADJ_DELEGATE_BFD);
+
+ if (NULL != aed)
+ {
+ aed->ad_bfd_state = adj_bfd_bfd_state_to_fib(session->local_state);
+ adj_bfd_update_walk(ai);
+ }
+ /*
+ * else
+ * not an adj with BFD state
+ */
+ break;
+
+ case BFD_LISTEN_EVENT_DELETE:
+ /*
+ * session has been removed.
+ */
+
+ if (adj_delegate_get(adj_get(ai), ADJ_DELEGATE_BFD))
+ {
+ /*
+ * has an associated BFD tracking delegate
+ * remove the BFD tracking deletgate, update children, then
+ * unlock the adj
+ */
+ adj_delegate_remove(adj_get(ai), ADJ_DELEGATE_BFD);
+
+ adj_bfd_update_walk(ai);
+ adj_unlock(ai);
+ }
+ /*
+ * else
+ * no BFD associated state
+ */
+ break;
+ }
+
+ /*
+ * unlock match of the add-or-lock at the start
+ */
+ adj_unlock(ai);
+}
+
+static clib_error_t *
+adj_bfd_main_init (vlib_main_t * vm)
+{
+ clib_error_t * error = NULL;
+
+ if ((error = vlib_call_init_function (vm, bfd_main_init)))
+ return (error);
+
+ bfd_register_listener(adj_bfd_notify);
+
+ return (error);
+}
+
+VLIB_INIT_FUNCTION (adj_bfd_main_init);