/****************************************************************************
* net/arp/arp_send.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/net/net.h>
#include <nuttx/net/netdev.h>
#include <nuttx/net/ip.h>
#include "netdev/netdev.h"
#include "devif/devif.h"
#include "route/route.h"
#include "arp/arp.h"
#ifdef CONFIG_NET_ARP_SEND
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: arp_send_terminate
****************************************************************************/
static void arp_send_terminate(FAR struct arp_send_s *state, int result)
{
/* Don't allow any further call backs. */
state->snd_sent = true;
state->snd_result = (int16_t)result;
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);
}
/****************************************************************************
* Name: arp_send_eventhandler
****************************************************************************/
static uint16_t arp_send_eventhandler(FAR struct net_driver_s *dev,
FAR void *priv, uint16_t flags)
{
FAR struct arp_send_s *state = (FAR struct arp_send_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 network is still up */
if ((flags & NETDEV_DOWN) != 0)
{
nerr("ERROR: Interface is down\n");
arp_send_terminate(state, -ENETUNREACH);
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 & PKT_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.
*/
arp_format(dev, state->snd_ipaddr);
/* Make sure no ARP request overwrites this ARP request. This
* flag will be cleared in arp_out().
*/
IFF_SET_NOARP(dev->d_flags);
/* Don't allow any further call backs. */
arp_send_terminate(state, OK);
}
return flags;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: arp_send
*
* Description:
* The arp_send() call may be to send an ARP request to resolve an IP
* address. This function first checks if the IP address is already in
* ARP table. If so, then it returns success immediately.
*
* If the requested IP address in not in the ARP table, then this function
* will send an ARP request, delay, then check if the IP address is now in
* the ARP table. It will repeat this sequence until either (1) the IP
* address mapping is now in the ARP table, or (2) a configurable number
* of timeouts occur without receiving the ARP replay.
*
* Input Parameters:
* ipaddr The IP address to be queried (in network order).
*
* Returned Value:
* Zero (OK) is returned on success and the IP address mapping can now be
* found in the ARP 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 arp_send(in_addr_t ipaddr)
{
FAR struct net_driver_s *dev;
struct arp_notify_s notify;
struct arp_send_s state;
int ret;
/* First check if destination is a local broadcast. */
if (ipaddr == INADDR_BROADCAST)
{
/* We don't need to send the ARP request */
return OK;
}
#ifdef CONFIG_NET_IGMP
/* Check if the destination address is a multicast address
*
* - IPv4: multicast addresses lie in the class D group -- The address
* range 224.0.0.0 to 239.255.255.255 (224.0.0.0/4)
*
* - IPv6 multicast addresses are have the high-order octet of the
* addresses=0xff (ff00::/8.)
*/
if (NTOHL(ipaddr) >= 0xe0000000 && NTOHL(ipaddr) <= 0xefffffff)
{
/* We don't need to send the ARP request */
return OK;
}
#endif
/* Get the device that can route this request */
dev = netdev_findby_ripv4addr(INADDR_ANY, ipaddr);
if (!dev)
{
nerr("ERROR: Unreachable: %08lx\n", (unsigned long)ipaddr);
ret = -EHOSTUNREACH;
goto errout;
}
/* ARP support is only built if the Ethernet link layer is supported.
* Continue and send the ARP request only if this device uses the
* Ethernet link layer protocol.
*/
if (dev->d_lltype != NET_LL_ETHERNET &&
dev->d_lltype != NET_LL_IEEE80211)
{
return OK;
}
/* Check if the destination address is on the local network. */
if (!net_ipv4addr_maskcmp(ipaddr, dev->d_ipaddr, dev->d_netmask))
{
in_addr_t dripaddr;
/* 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_ipv4_router(dev, ipaddr, &dripaddr);
#else
/* Use the device's default router IP address instead of the
* destination address when determining the MAC address.
*/
net_ipv4addr_copy(dripaddr, dev->d_draddr);
#endif
ipaddr = dripaddr;
}
/* The destination address is on the local network. Check if it is
* the sub-net broadcast address.
*/
else if (net_ipv4addr_broadcast(ipaddr, dev->d_netmask))
{
/* Yes.. We don't need to send the ARP request */
return OK;
}
/* 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 = arp_callback_alloc(dev);
if (!state.snd_cb)
{
nerr("ERROR: Failed to allocate a callback\n");
ret = -ENOMEM;
goto errout_with_lock;
}
nxsem_init(&state.snd_sem, 0, 0); /* Doesn't really fail */
state.snd_retries = 0; /* No retries yet */
state.snd_ipaddr = ipaddr; /* 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 ARP table and re-
* sending the ARP request if it is not.
*/
ret = -ETIMEDOUT; /* Assume a timeout failure */
while (state.snd_retries < CONFIG_ARP_SEND_MAXTRIES)
{
/* Check if the address mapping is present in the ARP table. This
* is only really meaningful on the first time through the loop.
*
* NOTE: If the ARP table is large than this could be a performance
* issue.
*/
if (arp_find(ipaddr, NULL, dev) >= 0)
{
/* We have it! Break out with success */
ret = OK;
break;
}
/* Set up the ARP response wait BEFORE we send the ARP request */
arp_wait_setup(ipaddr, ¬ify);
/* Arm/re-arm the callback */
state.snd_sent = false;
state.snd_result = -EBUSY;
state.snd_cb->flags = (ARP_POLL | NETDEV_DOWN);
state.snd_cb->priv = (FAR void *)&state;
state.snd_cb->event = arp_send_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_sem_wait will also terminate if a signal is received.
*/
do
{
ret = net_sem_timedwait_uninterruptible(&state.snd_sem,
CONFIG_ARP_SEND_DELAYMSEC);
if (ret == -ETIMEDOUT)
{
arp_wait_cancel(¬ify);
goto timeout;
}
}
while (!state.snd_sent);
/* Check the result of the send operation */
ret = state.snd_result;
if (ret < 0)
{
/* Break out on a send failure */
nerr("ERROR: Send failed: %d\n", ret);
arp_wait_cancel(¬ify);
break;
}
/* Now wait for response to the ARP response to be received. */
ret = arp_wait(¬ify, CONFIG_ARP_SEND_DELAYMSEC);
/* arp_wait will return OK if and only if the matching ARP response
* is received. Otherwise, it will return -ETIMEDOUT.
*/
if (ret >= OK)
{
/* Break out if arp_wait() fails */
break;
}
timeout:
/* Increment the retry count */
state.snd_retries++;
nerr("ERROR: arp_wait failed: %d\n", ret);
}
nxsem_destroy(&state.snd_sem);
arp_callback_free(dev, state.snd_cb);
errout_with_lock:
net_unlock();
errout:
return ret;
}
#endif /* CONFIG_NET_ARP_SEND */