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- /****************************************************************************
- * net/igmp/igmp_leave.c
- *
- * Copyright (C) 2010-2011, 2014, 2018 Gregory Nutt. All rights reserved.
- * Author: Gregory Nutt <gnutt@nuttx.org>
- *
- * The NuttX implementation of IGMP was inspired by the IGMP add-on for the
- * lwIP TCP/IP stack by Steve Reynolds:
- *
- * Copyright (c) 2002 CITEL Technologies Ltd.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. Neither the name of CITEL Technologies Ltd nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY CITEL TECHNOLOGIES AND CONTRIBUTORS ``AS IS''
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL CITEL TECHNOLOGIES OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- *
- ****************************************************************************/
- /****************************************************************************
- * Included Files
- ****************************************************************************/
- #include <nuttx/config.h>
- #include <assert.h>
- #include <debug.h>
- #include <netinet/in.h>
- #include <nuttx/wdog.h>
- #include <nuttx/net/netconfig.h>
- #include <nuttx/net/net.h>
- #include <nuttx/net/netstats.h>
- #include <nuttx/net/ip.h>
- #include <nuttx/net/igmp.h>
- #include "devif/devif.h"
- #include "igmp/igmp.h"
- #ifdef CONFIG_NET_IGMP
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: igmp_leavegroup
- *
- * Description:
- * Remove the specified group address to the group.
- *
- * RFC 2236, 3. Protocol Description:
- *
- * "When a host leaves a multicast group, if it was the last host to
- * reply to a Query with a Membership Report for that group, it SHOULD
- * send a Leave Group message to the all-routers multicast group
- * (224.0.0.2). If it was not the last host to reply to a Query, it MAY
- * send nothing as there must be another member on the subnet. This is
- * an optimization to reduce traffic; a host without sufficient storage
- * to remember whether or not it was the last host to reply MAY always
- * send a Leave Group message when it leaves a group. Routers SHOULD
- * accept a Leave Group message addressed to the group being left, in
- * order to accommodate implementations of an earlier version of this
- * standard. Leave Group messages are addressed to the all-routers
- * group because other group members have no need to know that a host
- * has left the group, but it does no harm to address the message to the
- * group."
- *
- * ________________
- * | |
- * | |
- * | |
- * | |
- * +--------->| Non-Member |<---------+
- * | | | |
- * | | | |
- * | | | |
- * | |________________| |
- * | | |
- * | leave group | join group | leave group
- * | (stop timer, |(send report, | (send leave
- * | send leave if | set flag, | if flag set)
- * | flag set) | start timer) |
- * ________|________ | ________|________
- * | |<---------+ | |
- * | | | |
- * | |<-------------------| |
- * | | query received | |
- * | Delaying Member | (start timer) | Idle Member |
- * +---->| |------------------->| |
- * | | | report received | |
- * | | | (stop timer, | |
- * | | | clear flag) | |
- * | |_________________|------------------->|_________________|
- * | query received | timer expired
- * | (reset timer if | (send report,
- * | Max Resp Time | set flag)
- * | < current timer) |
- * +-------------------+
- *
- * Assumptions:
- * The network is locked.
- *
- ****************************************************************************/
- int igmp_leavegroup(struct net_driver_s *dev,
- FAR const struct in_addr *grpaddr)
- {
- struct igmp_group_s *group;
- int ret;
- DEBUGASSERT(dev && grpaddr);
- /* Find the entry corresponding to the address leaving the group */
- group = igmp_grpfind(dev, &grpaddr->s_addr);
- ninfo("Leaving group: %p\n", group);
- if (group)
- {
- /* Cancel the timer and discard any queued Membership Reports.
- * Canceling the timer will prevent any new Membership Reports from
- * being sent; clearing the flags will discard any pending Membership
- * Reports that could interfere with the Leave Group.
- */
- wd_cancel(&group->wdog);
- CLR_SCHEDMSG(group->flags);
- CLR_WAITMSG(group->flags);
- IGMP_STATINCR(g_netstats.igmp.leaves);
- /* Send a leave if the flag is set according to the state diagram */
- if (IS_LASTREPORT(group->flags))
- {
- ninfo("Schedule Leave Group message\n");
- IGMP_STATINCR(g_netstats.igmp.leave_sched);
- ret = igmp_waitmsg(group, IGMP_LEAVE_GROUP);
- if (ret < 0)
- {
- nerr("ERROR: Failed to schedule message: %d\n", ret);
- }
- }
- /* Free the group structure (state is now Non-Member */
- igmp_grpfree(dev, group);
- /* And remove the group address from the drivers MAC filter set */
- igmp_removemcastmac(dev, (FAR in_addr_t *)&grpaddr->s_addr);
- return OK;
- }
- /* Return ENOENT if the address is not a member of the group */
- ninfo("Return -ENOENT\n");
- return -ENOENT;
- }
- #endif /* CONFIG_NET_IGMP */
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