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incubator-nuttx/net/icmpv6/icmpv6_autoconfig.c

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/****************************************************************************
* net/icmpv6/icmpv6_autoconfig.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 <stdint.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <arpa/inet.h>
#include <nuttx/semaphore.h>
#include <nuttx/net/net.h>
#include <nuttx/net/netdev.h>
#include "devif/devif.h"
#include "netdev/netdev.h"
#include "inet/inet.h"
#include "icmpv6/icmpv6.h"
#ifdef CONFIG_NET_ICMPv6_AUTOCONF
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure holds the state of the send operation until it can be
* operated upon by the event handler.
*/
struct icmpv6_router_s
{
FAR struct devif_callback_s *snd_cb; /* Reference to callback instance */
sem_t snd_sem; /* Used to wake up the waiting thread */
volatile bool snd_sent; /* True: if request sent */
bool snd_advertise; /* True: Send Neighbor Advertisement */
uint8_t snd_ifname[IFNAMSIZ]; /* Interface name */
int16_t snd_result; /* Result of the send */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: icmpv6_router_terminate
****************************************************************************/
static void icmpv6_router_terminate(FAR struct icmpv6_router_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: icmpv6_router_eventhandler
****************************************************************************/
static uint16_t icmpv6_router_eventhandler(FAR struct net_driver_s *dev,
FAR void *pvconn,
FAR void *priv, uint16_t flags)
{
FAR struct icmpv6_router_s *state = (FAR struct icmpv6_router_s *)priv;
ninfo("flags: %04x sent: %d\n", flags, state->snd_sent);
if (state)
{
/* Check if the network is still up */
if ((flags & NETDEV_DOWN) != 0)
{
nerr("ERROR: Interface is down\n");
icmpv6_router_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.
*/
else 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.
*/
if (state->snd_advertise)
{
/* Send the ICMPv6 Neighbor Advertisement message */
icmpv6_advertise(dev, g_ipv6_allnodes);
}
else
{
/* Send the ICMPv6 Router Solicitation message */
icmpv6_rsolicit(dev);
}
IFF_SET_IPv6(dev->d_flags);
/* Don't allow any further call backs. */
icmpv6_router_terminate(state, OK);
}
return flags;
}
/****************************************************************************
* Name: icmpv6_send_message
*
* Description:
* Send an ICMPv6 Router Solicitation to resolve an IPv6 address.
*
* Input Parameters:
* dev - The device to use to send the solicitation
* advertise - True: Send the Neighbor Advertisement message
*
* Returned Value:
* Zero (OK) is returned on success; On error a negated errno value is
* returned.
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
static int icmpv6_send_message(FAR struct net_driver_s *dev, bool advertise)
{
struct icmpv6_router_s state;
int ret;
/* 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);
/* Remember the routing device name */
strncpy((FAR char *)state.snd_ifname, (FAR const char *)dev->d_ifname,
IFNAMSIZ);
/* 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.
*/
state.snd_cb = devif_callback_alloc(dev, &dev->d_conncb);
if (!state.snd_cb)
{
nerr("ERROR: Failed to allocate a cllback\n");
ret = -ENOMEM;
goto errout_with_semaphore;
}
/* Arm the callback */
state.snd_sent = false;
state.snd_result = -EBUSY;
state.snd_advertise = advertise;
state.snd_cb->flags = (ICMPv6_POLL | NETDEV_DOWN);
state.snd_cb->priv = (FAR void *)&state;
state.snd_cb->event = icmpv6_router_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);
ret = state.snd_result;
devif_dev_callback_free(dev, state.snd_cb);
errout_with_semaphore:
nxsem_destroy(&state.snd_sem);
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: icmpv6_autoconfig
*
* Description:
* Perform IPv6 auto-configuration to assign an IPv6 address to this
* device.
*
* Stateless auto-configuration exploits several other features in IPv6,
* including link-local addresses, multi-casting, the Neighbor Discovery
* protocol, and the ability to generate the interface identifier of an
* address from the underlying link layer address. The general idea is
* to have a device generate a temporary address until it can determine
* the characteristics of the network it is on, and then create a permanent
* address it can use based on that information.
*
* Input Parameters:
* dev - The device driver structure to assign the address to
* psock - A pointer to a NuttX-specific, internal socket structure
*
* Returned Value:
* Zero (OK) is returned on success; A negated errno value is returned on
* any failure.
*
****************************************************************************/
int icmpv6_autoconfig(FAR struct net_driver_s *dev)
{
struct icmpv6_rnotify_s notify;
net_ipv6addr_t lladdr;
int retries;
int ret;
/* Sanity checks */
DEBUGASSERT(dev);
ninfo("Auto-configuring %s\n", dev->d_ifname);
/* Lock the network.
*
* NOTE: Normally it is required that the network be in the "down" state
* when re-configuring the network interface. This is thought not to be
* a problem here because.
*
* 1. The ICMPv6 logic here runs with the network locked so there can be
* no outgoing packets with bad source IP addresses from any
* asynchronous network activity using the device being reconfigured.
* 2. Incoming packets depend only upon the MAC filtering. Network
* drivers do not use the IP address; they filter incoming packets
* using only the MAC address which is not being changed here.
*/
net_lock();
/* IPv6 Stateless Autoconfiguration
* Reference:
* http://www.tcpipguide.com/free/t_IPv6AutoconfigurationandRenumbering.htm
*
* The following is a summary of the steps a device takes when using
* stateless auto-configuration:
*
* 1. Link-Local Address Generation: The device generates a link-local
* address. Recall that this is one of the two types of local-use IPv6
* addresses. Link-local addresses have "1111 1110 10" for the first
* ten bits. The generated address uses those ten bits followed by 54
* zeroes and then the 64 bit interface identifier. Typically this
* will be derived from the link layer (MAC) address.
*/
icmpv6_linkipaddr(dev, lladdr);
ninfo("lladdr=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
ntohs(lladdr[0]), ntohs(lladdr[1]),
ntohs(lladdr[2]), ntohs(lladdr[3]),
ntohs(lladdr[4]), ntohs(lladdr[5]),
ntohs(lladdr[6]), ntohs(lladdr[7]));
#ifdef CONFIG_NET_ICMPv6_NEIGHBOR
/* 2. Link-Local Address Uniqueness Test: The node tests to ensure that
* the address it generated isn't for some reason already in use on the
* local network. (This is very unlikely to be an issue if the link-
* local address came from a MAC address but more likely if it was
* based on a generated token.) It sends a Neighbor Solicitation
* message using the Neighbor Discovery (ND) protocol. It then listens
* for a Neighbor Advertisement in response that indicates that another
* device is already using its link-local address; if so, either a new
* address must be generated, or auto-configuration fails and another
* method must be employed.
*/
ret = icmpv6_neighbor(lladdr);
if (ret >= 0)
{
/* Hmmm... someone else responded to our Neighbor Solicitation. We
* have no back-up plan in place. Just bail.
*/
nerr("ERROR: IP conflict\n");
net_unlock();
return -EEXIST;
}
#endif
/* 3. Link-Local Address Assignment: Assuming the uniqueness test passes,
* the device assigns the link-local address to its IP interface. This
* address can be used for communication on the local network, but not
* on the wider Internet (since link-local addresses are not routed).
*/
net_ipv6addr_copy(dev->d_ipv6addr, lladdr);
/* 4. Router Contact: The node next attempts to contact a local router for
* more information on continuing the configuration. This is done either
* by listening for Router Advertisement messages sent periodically by
* routers, or by sending a specific Router Solicitation to ask a router
* for information on what to do next.
*/
for (retries = 0; retries < CONFIG_ICMPv6_AUTOCONF_MAXTRIES; retries++)
{
/* Set up the Router Advertisement BEFORE we send the Router
* Solicitation.
*/
icmpv6_rwait_setup(dev, &notify);
/* Send the ICMPv6 Router solicitation message */
ret = icmpv6_send_message(dev, false);
if (ret < 0)
{
nerr("ERROR: Failed send router solicitation: %d\n", ret);
break;
}
/* Wait to receive the Router Advertisement message */
ret = icmpv6_rwait(&notify, CONFIG_ICMPv6_AUTOCONF_DELAYMSEC);
if (ret != -ETIMEDOUT)
{
/* ETIMEDOUT is the only expected failure. We will retry on that
* case only.
*/
break;
}
ninfo("Timed out... retrying %d\n", retries + 1);
}
/* Check for failures. */
if (ret < 0)
{
int senderr;
nerr("ERROR: Failed to get the router advertisement: "
"%d (retries=%d)\n",
ret, retries);
/* Claim the link local address as ours by sending the ICMPv6 Neighbor
* Advertisement message.
*/
senderr = icmpv6_send_message(dev, true);
if (senderr < 0)
{
nerr("ERROR: Failed send neighbor advertisement: %d\n", senderr);
}
/* No off-link communications; No router address. */
net_ipv6addr_copy(dev->d_ipv6draddr, g_ipv6_unspecaddr);
/* Set a netmask for the local link address */
net_ipv6addr_copy(dev->d_ipv6netmask, g_ipv6_llnetmask);
}
/* 5. Router Direction: The router provides direction to the node on how
* to proceed with the auto-configuration. It may tell the node that on
* this network "stateful" auto-configuration is in use, and tell it
* the address of a DHCP server to use. Alternately, it will tell the
* host how to determine its global Internet address.
*
* 6. Global Address Configuration: Assuming that stateless auto-
* configuration is in use on the network, the host will configure
* itself with its globally-unique Internet address. This address is
* generally formed from a network prefix provided to the host by the
* router, combined with the device's identifier as generated in the
* first step.
*/
/* On success, the new address was already set (in icmpv_rnotify()). */
net_unlock();
return ret;
}
#endif /* CONFIG_NET_ICMPv6_AUTOCONF */
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