/****************************************************************************
* net/icmpv6/icmpv6_neighbor.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <unistd.h>
#include <string.h>
#include <debug.h>
#include <netinet/in.h>
#include <net/if.h>
#include <nuttx/semaphore.h>
#include <nuttx/net/net.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/ip.h>
#include <nuttx/net/icmpv6.h>
#include "netdev/netdev.h"
#include "devif/devif.h"
#include "inet/inet.h"
#include "neighbor/neighbor.h"
#include "route/route.h"
#include "icmpv6/icmpv6.h"
#ifdef CONFIG_NET_ICMPv6_NEIGHBOR
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure holds the state of the send operation until it can be
* operated upon from the event handler.
*/
struct icmpv6_neighbor_s
{
FAR struct devif_callback_s *snd_cb; /* Reference to callback instance */
sem_t snd_sem; /* Used to wake up the waiting thread */
uint8_t snd_retries; /* Retry count */
volatile bool snd_sent; /* True: if request sent */
uint8_t snd_ifname[IFNAMSIZ]; /* Interface name */
net_ipv6addr_t snd_ipaddr; /* The IPv6 address to be queried */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: icmpv6_neighbor_eventhandler
****************************************************************************/
static uint16_t icmpv6_neighbor_eventhandler(FAR struct net_driver_s *dev,
FAR void *priv, uint16_t flags)
{
FAR struct icmpv6_neighbor_s *state = (FAR struct icmpv6_neighbor_s *)priv;
ninfo("flags: %04x sent: %d\n", flags, state->snd_sent);
if (state)
{
/* Is this the device that we need to route this request? */
if (strncmp((FAR const char *)dev->d_ifname,
(FAR const char *)state->snd_ifname, IFNAMSIZ) != 0)
{
/* No... pass on this one and wait for the device that we want */
return flags;
}
/* Check if the outgoing packet is available. It may have been claimed
* by a send event handler serving a different thread -OR- if the
* output buffer currently contains unprocessed incoming data. In
* these cases we will just have to wait for the next polling cycle.
*/
if (dev->d_sndlen > 0 || (flags & ICMPv6_NEWDATA) != 0)
{
/* Another thread has beat us sending data or the buffer is busy,
* Check for a timeout. If not timed out, wait for the next
* polling cycle and check again.
*/
/* REVISIT: No timeout. Just wait for the next polling cycle */
return flags;
}
/* It looks like we are good to send the data.
*
* Copy the packet data into the device packet buffer and send it.
*/
icmpv6_solicit(dev, state->snd_ipaddr);
IFF_SET_IPv6(dev->d_flags);
/* Don't allow any further call backs. */
state->snd_sent = true;
state->snd_cb->flags = 0;
state->snd_cb->priv = NULL;
state->snd_cb->event = NULL;
/* Wake up the waiting thread */
nxsem_post(&state->snd_sem);
}
return flags;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: icmpv6_neighbor
*
* Description:
* The icmpv6_solicit() call may be to send an ICMPv6 Neighbor
* Solicitation to resolve an IPv6 address. This function first checks if
* the IPv6 address is already in the Neighbor Table. If so, then it
* returns success immediately.
*
* If the requested IPv6 address in not in the Neighbor Table, then this
* function will send the Neighbor Solicitation, delay, then check if the
* IP address is now in the Neighbor able. It will repeat this sequence
* until either (1) the IPv6 address mapping is now in the Neighbor table,
* or (2) a configurable number of timeouts occur without receiving the
* ICMPv6 Neighbor Advertisement.
*
* Input Parameters:
* ipaddr The IPv6 address to be queried.
*
* Returned Value:
* Zero (OK) is returned on success and the IP address mapping can now be
* found in the Neighbor Table. On error a negated errno value is
* returned:
*
* -ETIMEDOUT: The number or retry counts has been exceed.
* -EHOSTUNREACH: Could not find a route to the host
*
* Assumptions:
* This function is called from the normal tasking context.
*
****************************************************************************/
int icmpv6_neighbor(const net_ipv6addr_t ipaddr)
{
FAR struct net_driver_s *dev;
struct icmpv6_notify_s notify;
struct icmpv6_neighbor_s state;
net_ipv6addr_t lookup;
int ret;
/* First check if destination is a local broadcast or a multicast address.
*
* - IPv6 multicast addresses are have the high-order octet of the
* addresses=0xff (ff00::/8.)
*/
if (net_ipv6addr_cmp(ipaddr, g_ipv6_unspecaddr) ||
net_is_addr_mcast(ipaddr))
{
/* We don't need to send the Neighbor Solicitation. But for the case
* of the Multicast address, a routing able entry will be required.
*/
return OK;
}
/* Get the device that can route this request */
dev = netdev_findby_ripv6addr(g_ipv6_unspecaddr, ipaddr);
if (!dev)
{
nerr("ERROR: Unreachable: %08lx\n", (unsigned long)ipaddr);
ret = -EHOSTUNREACH;
goto errout;
}
/* Check if the destination address is on the local network. */
if (net_ipv6addr_maskcmp(ipaddr, dev->d_ipv6addr, dev->d_ipv6netmask))
{
/* Yes.. use the input address for the lookup */
net_ipv6addr_copy(lookup, ipaddr);
}
else
{
/* Destination address is not on the local network */
#ifdef CONFIG_NET_ROUTE
/* We have a routing table.. find the correct router to use in
* this case (or, as a fall-back, use the device's default router
* address). We will use the router IP address instead of the
* destination address when determining the MAC address.
*/
netdev_ipv6_router(dev, ipaddr, lookup);
#else
/* Use the device's default router IP address instead of the
* destination address when determining the MAC address.
*/
net_ipv6addr_copy(lookup, dev->d_ipv6draddr);
#endif
}
/* Allocate resources to receive a callback. This and the following
* initialization is performed with the network lock because we don't
* want anything to happen until we are ready.
*/
net_lock();
state.snd_cb = devif_callback_alloc((dev),
&(dev)->d_conncb,
&(dev)->d_conncb_tail);
if (!state.snd_cb)
{
nerr("ERROR: Failed to allocate a callback\n");
ret = -ENOMEM;
goto errout_with_lock;
}
/* Initialize the state structure with the network locked.
*
* This semaphore is used for signaling and, hence, should not have
* priority inheritance enabled.
*/
nxsem_init(&state.snd_sem, 0, 0); /* Doesn't really fail */
nxsem_set_protocol(&state.snd_sem, SEM_PRIO_NONE);
state.snd_retries = 0; /* No retries yet */
net_ipv6addr_copy(state.snd_ipaddr, lookup); /* IP address to query */
/* Remember the routing device name */
strlcpy((FAR char *)state.snd_ifname, (FAR const char *)dev->d_ifname,
IFNAMSIZ);
/* Now loop, testing if the address mapping is in the Neighbor Table and
* re-sending the Neighbor Solicitation if it is not.
*/
ret = -ETIMEDOUT; /* Assume a timeout failure */
while (state.snd_retries < CONFIG_ICMPv6_NEIGHBOR_MAXTRIES)
{
/* Check if the address mapping is present in the Neighbor Table. This
* is only really meaningful on the first time through the loop.
*
* NOTE: If the Neighbor Table is large than this could be a
* performance issue.
*/
if (neighbor_lookup(lookup, NULL) >= 0)
{
/* We have it! Break out with success */
ret = OK;
break;
}
/* Set up the Neighbor Advertisement wait BEFORE we send the Neighbor
* Solicitation.
*/
icmpv6_wait_setup(lookup, ¬ify);
/* Arm/re-arm the callback */
state.snd_sent = false;
state.snd_cb->flags = ICMPv6_POLL;
state.snd_cb->priv = (FAR void *)&state;
state.snd_cb->event = icmpv6_neighbor_eventhandler;
/* Notify the device driver that new TX data is available. */
netdev_txnotify_dev(dev);
/* Wait for the send to complete or an error to occur.
* net_lockedwait will also terminate if a signal is received.
*/
do
{
net_lockedwait(&state.snd_sem);
}
while (!state.snd_sent);
/* Now wait for response to the Neighbor Advertisement to be
* received.
*/
ret = icmpv6_wait(¬ify, CONFIG_ICMPv6_NEIGHBOR_DELAYMSEC);
/* icmpv6_wait will return OK if and only if the matching Neighbor
* Advertisement is received. Otherwise, it will return -ETIMEDOUT.
*/
if (ret == OK)
{
break;
}
/* Increment the retry count */
state.snd_retries++;
}
nxsem_destroy(&state.snd_sem);
devif_dev_callback_free(dev, state.snd_cb);
errout_with_lock:
net_unlock();
errout:
return ret;
}
#endif /* CONFIG_NET_ICMPv6_NEIGHBOR */