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incubator-nuttx/net/igmp/igmp_timer.c

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/****************************************************************************
* net/igmp/igmp_timer.c
*
* Copyright (C) 2010-2011, 2014 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 <nuttx/compiler.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/wdog.h>
#include <nuttx/irq.h>
#include <nuttx/net/netconfig.h>
#include <nuttx/net/net.h>
#include <nuttx/net/netstats.h>
#include <nuttx/net/igmp.h>
#include "devif/devif.h"
#include "igmp/igmp.h"
#include "utils/utils.h"
#ifdef CONFIG_NET_IGMP
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Debug ********************************************************************/
#undef IGMP_GTMRDEBUG /* Define to enable detailed IGMP group debug */
#ifndef CONFIG_NET_IGMP
# undef IGMP_GTMRDEBUG
#endif
#ifdef CONFIG_CPP_HAVE_VARARGS
# ifdef IGMP_GTMRDEBUG
# define gtmrerr(format, ...) nerr(format, ##__VA_ARGS__)
# define gtmrinfo(format, ...) ninfo(format, ##__VA_ARGS__)
# else
# define gtmrerr(x...)
# define gtmrinfo(x...)
# endif
#else
# ifdef IGMP_GTMRDEBUG
# define gtmrerr nerr
# define gtmrinfo ninfo
# else
# define gtmrerr (void)
# define gtmrinfo (void)
# endif
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: igmp_timeout
*
* Description:
* Timeout watchdog handler.
*
* Assumptions:
* This function is called from the wdog timer handler which runs in the
* context of the timer interrupt handler.
*
****************************************************************************/
static void igmp_timeout(int argc, uint32_t arg, ...)
{
FAR struct igmp_group_s *group;
/* If the state is DELAYING_MEMBER then we send a report for this group */
ninfo("Timeout!\n");
group = (FAR struct igmp_group_s *)arg;
DEBUGASSERT(argc == 1 && group);
/* If the group exists and is no an IDLE MEMBER, then it must be a DELAYING
* member. Race conditions are avoided because (1) the timer is not started
* until after the first IGMPv2_MEMBERSHIP_REPORT during the join, and (2)
* the timer is cancelled before sending the IGMP_LEAVE_GROUP during a leave.
*/
if (!IS_IDLEMEMBER(group->flags))
{
/* Schedule (and forget) the Membership Report. NOTE:
* Since we are executing from a timer interrupt, we cannot wait
* for the message to be sent.
*/
IGMP_STATINCR(g_netstats.igmp.report_sched);
igmp_schedmsg(group, IGMPv2_MEMBERSHIP_REPORT);
/* Also note: The Membership Report is sent at most two times becasue
* the timer is not reset here. Hmm.. does this mean that the group
* is stranded if both reports were lost? This is consistent with the
* RFC that states: "To cover the possibility of the initial Membership
* Report being lost or damaged, it is recommended that it be repeated
* once or twice after short delays [Unsolicited Report Interval]..."
*/
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: igmp_startticks and igmp_starttimer
*
* Description:
* Start the IGMP timer with differing time units (ticks or deciseconds).
*
* Assumptions:
* This function may be called from most any context.
*
****************************************************************************/
void igmp_startticks(FAR struct igmp_group_s *group, unsigned int ticks)
{
int ret;
/* Start the timer */
gtmrinfo("ticks: %d\n", ticks);
ret = wd_start(group->wdog, ticks, igmp_timeout, 1, (uint32_t)group);
DEBUGASSERT(ret == OK);
UNUSED(ret);
}
void igmp_starttimer(FAR struct igmp_group_s *group, uint8_t decisecs)
{
/* Convert the decisec value to system clock ticks and start the timer.
* Important!! this should be a random timer from 0 to decisecs
*/
gtmrinfo("decisecs: %d\n", decisecs);
igmp_startticks(group, net_dsec2tick(decisecs));
}
/****************************************************************************
* Name: igmp_cmptimer
*
* Description:
* Compare the timer remaining on the watching timer to the deci-second
* value. If maxticks > ticks-remaining, then (1) cancel the timer (to
* avoid race conditions) and return true.
*
* Assumptions:
* This function may be called from most any context. If true is returned
* then the caller must call igmp_startticks() to restart the timer
*
****************************************************************************/
bool igmp_cmptimer(FAR struct igmp_group_s *group, int maxticks)
{
irqstate_t flags;
int remaining;
/* Disable interrupts so that there is no race condition with the actual
* timer expiration.
*/
flags = enter_critical_section();
/* Get the timer remaining on the watchdog. A time of <= zero means that
* the watchdog was never started.
*/
remaining = wd_gettime(group->wdog);
/* A remaining time of zero means that the watchdog was never started
* or has already expired. That case should be covered in the following
* test as well.
*/
gtmrinfo("maxticks: %d remaining: %d\n", maxticks, remaining);
if (maxticks > remaining)
{
/* Cancel the watchdog timer and return true */
wd_cancel(group->wdog);
leave_critical_section(flags);
return true;
}
leave_critical_section(flags);
return false;
}
#endif /* CONFIG_NET_IGMP */
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