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px4-firmware/nuttx/net/uip/uip_igmpleave.c

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/****************************************************************************
* net/uip/uip_igmpleave.c
*
* Copyright (C) 2010-2011 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 <wdog.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/net/uip/uipopt.h>
#include <nuttx/net/uip/uip.h>
#include <nuttx/net/uip/uip-igmp.h>
#include "uip_internal.h"
#ifdef CONFIG_NET_IGMP
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* 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:
* This function cannot be called from interrupt handling logic!
*
****************************************************************************/
int igmp_leavegroup(struct uip_driver_s *dev, FAR const struct in_addr *grpaddr)
{
struct igmp_group_s *group;
uip_lock_t flags;
DEBUGASSERT(dev && grpaddr);
/* Find the entry corresponding to the address leaving the group */
group = uip_grpfind(dev, &grpaddr->s_addr);
ndbg("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.
*/
flags = uip_lock();
wd_cancel(group->wdog);
CLR_SCHEDMSG(group->flags);
CLR_WAITMSG(group->flags);
uip_unlock(flags);
IGMP_STATINCR(uip_stat.igmp.leaves);
/* Send a leave if the flag is set according to the state diagram */
if (IS_LASTREPORT(group->flags))
{
ndbg("Schedule Leave Group message\n");
IGMP_STATINCR(uip_stat.igmp.leave_sched);
uip_igmpwaitmsg(group, IGMP_LEAVE_GROUP);
}
/* Free the group structure (state is now Non-Member */
uip_grpfree(dev, group);
/* And remove the group address from the ethernet drivers MAC filter set */
uip_removemcastmac(dev, (FAR uip_ipaddr_t *)&grpaddr->s_addr);
return OK;
}
/* Return ENOENT if the address is not a member of the group */
nvdbg("Return -ENOENT\n");
return -ENOENT;
}
#endif /* CONFIG_NET_IGMP */
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