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