92 lines
3.6 KiB
C
92 lines
3.6 KiB
C
/****************************************************************************
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* net/mld/mld_done.c
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/net/netstats.h>
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#include <nuttx/net/netdev.h>
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#include <nuttx/net/mld.h>
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#include "devif/devif.h"
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#include "mld/mld.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: mld_done
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*
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* Description:
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* Called from icmpv6_input() when a Multicast Listener Done is received.
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*
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* When a router in Querier state receives a Done message from a link,
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* if the Multicast Address identified in the message is present in the
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* Querier's list of addresses having listeners on that link, the Querier
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* periodically sends multiple Multicast-Address-Specific Queries to that
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* multicast address. If no Reports for the address are received from the
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* link after the maximum response delay in the Multicast-Address-Specific
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* Queries of the last query has passed, the routers on the link assume
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* that the address no longer has any listeners there; the address is
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* therefore deleted from the list and its disappearance is made known to
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* the multicast routing component.
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*
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* Routers in Non-Querier state MUST ignore Done messages.
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*
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****************************************************************************/
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int mld_done(FAR struct net_driver_s *dev,
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FAR const struct mld_mcast_listen_done_s *done)
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{
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mldinfo("Multicast Listener Done\n");
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MLD_STATINCR(g_netstats.mld.done_received);
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/* The Done message is sent to the link-local, all routers multicast
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* address. We basically ignore the Done message:
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*
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* We cannot free the group if there are other members of the group. We
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* know how many local tasks have joined the group, but we are less
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* certain of how many non-local members of the group there are.
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*
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* The RFC requires that we send Multicast-Address-Specific Queries
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* repeatedly before removing the group to assure that the no listeners
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* are present.
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*
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* If we are the Querier, then the Query timer logic will accomplish
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* this requirement for us. If there is another Querier on the subnet,
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* it will drive the Queries. No Querier? We will let the 'Other
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* Querier Present Timeout' handle that case.
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*/
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/* Need to set d_len to zero to indication that nothing is being sent */
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dev->d_len = 0;
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return OK;
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}
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