466 lines
15 KiB
C
466 lines
15 KiB
C
/****************************************************************************
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* net/icmpv6/icmpv6_autoconfig.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <string.h>
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#include <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <arpa/inet.h>
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#include <nuttx/semaphore.h>
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#include <nuttx/net/net.h>
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#include <nuttx/net/netdev.h>
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#include "devif/devif.h"
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#include "netdev/netdev.h"
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#include "inet/inet.h"
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#include "icmpv6/icmpv6.h"
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#include "utils/utils.h"
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#ifdef CONFIG_NET_ICMPv6_AUTOCONF
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/****************************************************************************
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* Private Types
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****************************************************************************/
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/* This structure holds the state of the send operation until it can be
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* operated upon by the event handler.
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*/
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struct icmpv6_router_s
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{
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FAR struct devif_callback_s *snd_cb; /* Reference to callback instance */
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sem_t snd_sem; /* Used to wake up the waiting thread */
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volatile bool snd_sent; /* True: if request sent */
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bool snd_advertise; /* True: Send Neighbor Advertisement */
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uint8_t snd_ifname[IFNAMSIZ]; /* Interface name */
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int16_t snd_result; /* Result of the send */
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: icmpv6_router_terminate
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****************************************************************************/
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static void icmpv6_router_terminate(FAR struct icmpv6_router_s *state,
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int result)
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{
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/* Don't allow any further call backs. */
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state->snd_sent = true;
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state->snd_result = (int16_t)result;
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state->snd_cb->flags = 0;
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state->snd_cb->priv = NULL;
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state->snd_cb->event = NULL;
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/* Wake up the waiting thread */
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nxsem_post(&state->snd_sem);
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}
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/****************************************************************************
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* Name: icmpv6_router_eventhandler
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****************************************************************************/
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static uint16_t icmpv6_router_eventhandler(FAR struct net_driver_s *dev,
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FAR void *priv, uint16_t flags)
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{
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FAR struct icmpv6_router_s *state = (FAR struct icmpv6_router_s *)priv;
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ninfo("flags: %04x sent: %d\n", flags, state->snd_sent);
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if (state)
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{
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/* Check if the network is still up */
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if ((flags & NETDEV_DOWN) != 0)
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{
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nerr("ERROR: Interface is down\n");
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icmpv6_router_terminate(state, -ENETUNREACH);
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return flags;
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}
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/* Check if the outgoing packet is available. It may have been claimed
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* by a send event handler serving a different thread -OR- if the
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* output buffer currently contains unprocessed incoming data. In
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* these cases we will just have to wait for the next polling cycle.
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*/
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else if (dev->d_sndlen > 0 || (flags & ICMPv6_NEWDATA) != 0)
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{
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/* Another thread has beat us sending data or the buffer is busy,
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* Check for a timeout. If not timed out, wait for the next
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* polling cycle and check again.
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*/
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/* REVISIT: No timeout. Just wait for the next polling cycle */
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return flags;
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}
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/* Prepare device buffer */
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if (netdev_iob_prepare(dev, false, 0) != OK)
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{
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return flags;
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}
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/* It looks like we are good to send the data.
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*
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* Copy the packet data into the device packet buffer and send it.
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*/
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if (state->snd_advertise)
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{
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/* Send the ICMPv6 Neighbor Advertisement message, we should
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* already have link-local address by previous logic.
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*/
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icmpv6_advertise(dev, netdev_ipv6_lladdr(dev), g_ipv6_allnodes);
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}
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else
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{
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/* Send the ICMPv6 Router Solicitation message */
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icmpv6_rsolicit(dev);
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}
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IFF_SET_IPv6(dev->d_flags);
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/* Don't allow any further call backs. */
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icmpv6_router_terminate(state, OK);
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}
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return flags;
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}
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/****************************************************************************
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* Name: icmpv6_send_message
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*
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* Description:
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* Send an ICMPv6 Router Solicitation to resolve an IPv6 address.
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*
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* Input Parameters:
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* dev - The device to use to send the solicitation
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* advertise - True: Send the Neighbor Advertisement message
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*
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* Returned Value:
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* Zero (OK) is returned on success; On error a negated errno value is
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* returned.
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*
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* Assumptions:
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* The network is locked.
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*
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****************************************************************************/
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static int icmpv6_send_message(FAR struct net_driver_s *dev, bool advertise)
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{
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struct icmpv6_router_s state;
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int ret;
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/* Initialize the state structure with the network locked. */
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nxsem_init(&state.snd_sem, 0, 0); /* Doesn't really fail */
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/* Remember the routing device name */
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strlcpy((FAR char *)state.snd_ifname, (FAR const char *)dev->d_ifname,
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IFNAMSIZ);
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/* Allocate resources to receive a callback. This and the following
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* initialization is performed with the network lock because we don't
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* want anything to happen until we are ready.
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*/
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state.snd_cb = devif_callback_alloc(dev,
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&dev->d_conncb,
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&dev->d_conncb_tail);
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if (!state.snd_cb)
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{
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nerr("ERROR: Failed to allocate a cllback\n");
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ret = -ENOMEM;
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goto errout_with_semaphore;
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}
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/* Arm the callback */
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state.snd_sent = false;
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state.snd_result = -EBUSY;
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state.snd_advertise = advertise;
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state.snd_cb->flags = (ICMPv6_POLL | NETDEV_DOWN);
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state.snd_cb->priv = (FAR void *)&state;
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state.snd_cb->event = icmpv6_router_eventhandler;
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/* Notify the device driver that new TX data is available. */
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netdev_txnotify_dev(dev);
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/* Wait for the send to complete or an error to occur
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* net_sem_wait will also terminate if a signal is received.
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*/
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do
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{
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net_sem_wait(&state.snd_sem);
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}
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while (!state.snd_sent);
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ret = state.snd_result;
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devif_dev_callback_free(dev, state.snd_cb);
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errout_with_semaphore:
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nxsem_destroy(&state.snd_sem);
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return ret;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: icmpv6_autoconfig
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*
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* Description:
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* Perform IPv6 auto-configuration to assign an IPv6 address to this
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* device.
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*
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* Stateless auto-configuration exploits several other features in IPv6,
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* including link-local addresses, multi-casting, the Neighbor Discovery
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* protocol, and the ability to generate the interface identifier of an
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* address from the underlying link layer address. The general idea is
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* to have a device generate a temporary address until it can determine
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* the characteristics of the network it is on, and then create a permanent
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* address it can use based on that information.
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*
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* Input Parameters:
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* dev - The device driver structure to assign the address to
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* psock - A pointer to a NuttX-specific, internal socket structure
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*
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* Returned Value:
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* Zero (OK) is returned on success; A negated errno value is returned on
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* any failure.
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*
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****************************************************************************/
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int icmpv6_autoconfig(FAR struct net_driver_s *dev)
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{
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struct icmpv6_rnotify_s notify;
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net_ipv6addr_t lladdr;
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int retries;
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int ret;
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/* Sanity checks */
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DEBUGASSERT(dev);
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ninfo("Auto-configuring %s\n", dev->d_ifname);
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/* Lock the network.
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*
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* NOTE: Normally it is required that the network be in the "down" state
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* when re-configuring the network interface. This is thought not to be
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* a problem here because.
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*
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* 1. The ICMPv6 logic here runs with the network locked so there can be
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* no outgoing packets with bad source IP addresses from any
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* asynchronous network activity using the device being reconfigured.
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* 2. Incoming packets depend only upon the MAC filtering. Network
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* drivers do not use the IP address; they filter incoming packets
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* using only the MAC address which is not being changed here.
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*/
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net_lock();
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/* IPv6 Stateless Autoconfiguration
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* Reference:
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* http://www.tcpipguide.com/free/t_IPv6AutoconfigurationandRenumbering.htm
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*
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* The following is a summary of the steps a device takes when using
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* stateless auto-configuration:
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*
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* 1. Link-Local Address Generation: The device generates a link-local
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* address. Recall that this is one of the two types of local-use IPv6
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* addresses. Link-local addresses have "1111 1110 10" for the first
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* ten bits. The generated address uses those ten bits followed by 54
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* zeroes and then the 64 bit interface identifier. Typically this
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* will be derived from the link layer (MAC) address.
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*/
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if (netdev_ipv6_lladdr(dev) != NULL)
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{
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goto got_lladdr;
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}
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icmpv6_linkipaddr(dev, lladdr);
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ninfo("lladdr=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
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NTOHS(lladdr[0]), NTOHS(lladdr[1]),
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NTOHS(lladdr[2]), NTOHS(lladdr[3]),
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NTOHS(lladdr[4]), NTOHS(lladdr[5]),
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NTOHS(lladdr[6]), NTOHS(lladdr[7]));
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#ifdef CONFIG_NET_ICMPv6_NEIGHBOR
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/* 2. Link-Local Address Uniqueness Test: The node tests to ensure that
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* the address it generated isn't for some reason already in use on the
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* local network. (This is very unlikely to be an issue if the link-
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* local address came from a MAC address but more likely if it was
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* based on a generated token.) It sends a Neighbor Solicitation
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* message using the Neighbor Discovery (ND) protocol. It then listens
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* for a Neighbor Advertisement in response that indicates that another
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* device is already using its link-local address; if so, either a new
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* address must be generated, or auto-configuration fails and another
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* method must be employed.
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*/
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if (dev->d_lltype == NET_LL_ETHERNET ||
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dev->d_lltype == NET_LL_IEEE80211)
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{
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ret = icmpv6_neighbor(dev, lladdr);
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if (ret >= 0)
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{
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/* Hmmm... someone else responded to our Neighbor Solicitation. We
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* have no back-up plan in place. Just bail.
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*/
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nerr("ERROR: IP conflict\n");
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net_unlock();
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return -EEXIST;
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}
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}
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#endif
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/* 3. Link-Local Address Assignment: Assuming the uniqueness test passes,
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* the device assigns the link-local address to its IP interface. This
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* address can be used for communication on the local network, but not
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* on the wider Internet (since link-local addresses are not routed).
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*/
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ret = netdev_ipv6_add(dev, lladdr, net_ipv6_mask2pref(g_ipv6_llnetmask));
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if (ret < 0)
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{
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net_unlock();
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return ret;
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}
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got_lladdr:
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/* 4. Router Contact: The node next attempts to contact a local router for
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* more information on continuing the configuration. This is done either
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* by listening for Router Advertisement messages sent periodically by
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* routers, or by sending a specific Router Solicitation to ask a router
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* for information on what to do next.
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*/
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for (retries = 0; retries < CONFIG_ICMPv6_AUTOCONF_MAXTRIES; retries++)
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{
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/* Set up the Router Advertisement BEFORE we send the Router
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* Solicitation.
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*/
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icmpv6_rwait_setup(dev, ¬ify);
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/* Send the ICMPv6 Router solicitation message */
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ret = icmpv6_send_message(dev, false);
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if (ret < 0)
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{
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/* Remove our wait structure from the list (we may no longer be
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* at the head of the list).
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*/
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icmpv6_rwait_cancel(¬ify);
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nerr("ERROR: Failed send router solicitation: %d\n", ret);
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break;
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}
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/* Wait to receive the Router Advertisement message */
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ret = icmpv6_rwait(¬ify, CONFIG_ICMPv6_AUTOCONF_DELAYMSEC);
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if (ret != -ETIMEDOUT)
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{
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/* ETIMEDOUT is the only expected failure. We will retry on that
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* case only.
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*/
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break;
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}
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ninfo("Timed out... retrying %d\n", retries + 1);
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}
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/* Check for failures. */
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if (ret < 0)
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{
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int senderr;
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nerr("ERROR: Failed to get the router advertisement: "
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"%d (retries=%d)\n",
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ret, retries);
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/* Claim the link local address as ours by sending the ICMPv6 Neighbor
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* Advertisement message.
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*/
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senderr = icmpv6_send_message(dev, true);
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if (senderr < 0)
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{
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nerr("ERROR: Failed send neighbor advertisement: %d\n", senderr);
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}
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/* No off-link communications; No router address. */
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net_ipv6addr_copy(dev->d_ipv6draddr, g_ipv6_unspecaddr);
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}
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/* 5. Router Direction: The router provides direction to the node on how
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* to proceed with the auto-configuration. It may tell the node that on
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* this network "stateful" auto-configuration is in use, and tell it
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* the address of a DHCP server to use. Alternately, it will tell the
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* host how to determine its global Internet address.
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*
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* 6. Global Address Configuration: Assuming that stateless auto-
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* configuration is in use on the network, the host will configure
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* itself with its globally-unique Internet address. This address is
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* generally formed from a network prefix provided to the host by the
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* router, combined with the device's identifier as generated in the
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* first step.
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*/
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/* On success, the new address was already set (in icmpv_rnotify()). */
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net_unlock();
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return ret;
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}
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#endif /* CONFIG_NET_ICMPv6_AUTOCONF */
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