/****************************************************************************
* net/arp/arp_notify.c
*
* Copyright (C) 2014, 2016 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 NuttX 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 THE COPYRIGHT HOLDERS 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 THE
* COPYRIGHT OWNER 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 <time.h>
#include <semaphore.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <netinet/in.h>
#include <nuttx/irq.h>
#include <nuttx/semaphore.h>
#include <nuttx/net/net.h>
#include "arp/arp.h"
#ifdef CONFIG_NET_ARP_SEND
/****************************************************************************
* Private Data
****************************************************************************/
/* List of tasks waiting for ARP events */
static FAR struct arp_notify_s *g_arp_waiters;
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: arp_wait_setup
*
* Description:
* Called BEFORE an ARP request is sent. This function sets up the ARP
* response timeout before the ARP request is sent so that there is
* no race condition when arp_wait() is called.
*
* Assumptions:
* This function is called from ARP send and executes in the normal
* tasking environment.
*
****************************************************************************/
void arp_wait_setup(in_addr_t ipaddr, FAR struct arp_notify_s *notify)
{
irqstate_t flags;
/* Initialize the wait structure */
notify->nt_ipaddr = ipaddr;
notify->nt_result = -ETIMEDOUT;
/* This semaphore is used for signaling and, hence, should not have
* priority inheritance enabled.
*/
(void)sem_init(¬ify->nt_sem, 0, 0);
sem_setprotocol(¬ify->nt_sem, SEM_PRIO_NONE);
/* Add the wait structure to the list with interrupts disabled */
flags = enter_critical_section();
notify->nt_flink = g_arp_waiters;
g_arp_waiters = notify;
leave_critical_section(flags);
}
/****************************************************************************
* Name: arp_wait_cancel
*
* Description:
* Cancel any wait set after arp_wait_setup is called but before arp_wait()
* is called (arp_wait() will automatically cancel the wait).
*
* Assumptions:
* This function may execute in the interrupt context when called from
* arp_wait().
*
****************************************************************************/
int arp_wait_cancel(FAR struct arp_notify_s *notify)
{
FAR struct arp_notify_s *curr;
FAR struct arp_notify_s *prev;
irqstate_t flags;
int ret = -ENOENT;
/* Remove our wait structure from the list (we may no longer be at the
* head of the list).
*/
flags = enter_critical_section();
for (prev = NULL, curr = g_arp_waiters;
curr && curr != notify;
prev = curr, curr = curr->nt_flink);
DEBUGASSERT(curr && curr == notify);
if (curr)
{
if (prev)
{
prev->nt_flink = notify->nt_flink;
}
else
{
g_arp_waiters = notify->nt_flink;
}
ret = OK;
}
leave_critical_section(flags);
(void)sem_destroy(¬ify->nt_sem);
return ret;
}
/****************************************************************************
* Name: arp_wait
*
* Description:
* Called each time that a ARP request is sent. This function will sleep
* until either: (1) the matching ARP response is received, or (2) a
* timeout occurs.
*
* Assumptions:
* This function is called from ARP send must execute with the network
* locked.
*
****************************************************************************/
int arp_wait(FAR struct arp_notify_s *notify, FAR struct timespec *timeout)
{
struct timespec abstime;
irqstate_t flags;
int errcode;
int ret;
/* And wait for the ARP response (or a timeout). Interrupts will be re-
* enabled while we wait.
*/
flags = enter_critical_section();
DEBUGVERIFY(clock_gettime(CLOCK_REALTIME, &abstime));
abstime.tv_sec += timeout->tv_sec;
abstime.tv_nsec += timeout->tv_nsec;
if (abstime.tv_nsec >= 1000000000)
{
abstime.tv_sec++;
abstime.tv_nsec -= 1000000000;
}
/* Wait to get either the correct response or a timeout. */
do
{
/* The only errors that we expect would be if the abstime timeout
* expires or if the wait were interrupted by a signal.
*/
ret = net_timedwait(¬ify->nt_sem, &abstime);
errcode = ((ret < 0) ? get_errno() : 0);
}
while (ret < 0 && errcode == EINTR);
/* Then get the real result of the transfer */
ret = notify->nt_result;
/* Remove our wait structure from the list (we may no longer be at the
* head of the list).
*/
(void)arp_wait_cancel(notify);
/* Re-enable interrupts and return the result of the wait */
leave_critical_section(flags);
return ret;
}
/****************************************************************************
* Name: arp_notify
*
* Description:
* Called each time that a ARP response is received in order to wake-up
* any threads that may be waiting for this particular ARP response.
*
* Assumptions:
* This function is called from the MAC device driver indirectly through
* arp_arpin() will execute with the network locked.
*
****************************************************************************/
void arp_notify(in_addr_t ipaddr)
{
FAR struct arp_notify_s *curr;
/* Find an entry with the matching IP address in the list of waiters */
for (curr = g_arp_waiters; curr; curr = curr->nt_flink)
{
/* Does this entry match? If the result is okay, then we have
* already notified this waiter and it has not yet taken the
* entry from the list.
*/
if (curr->nt_result != OK && curr->nt_ipaddr == ipaddr)
{
/* Yes.. Signal the waiting, returning success */
curr->nt_result = OK;
sem_post(&curr->nt_sem);
break;
}
}
}
#endif /* CONFIG_NET_ARP_SEND */