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nuttx/net/icmpv6/icmpv6_autoconfig.c
Gregory Nutt 6f3f43d930 IPv6: Add a netmaks for the local link address
2015-02-05 05:43:57 -06:00

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/****************************************************************************
* net/icmpv6/icmpv6_autoconfig.c
*
* Copyright (C) 2015 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 <stdint.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include <debug.h>
#include <net/ethernet.h>
#include <nuttx/net/net.h>
#include <nuttx/net/netdev.h>
#include "devif/devif.h"
#include "netdev/netdev.h"
#include "icmpv6/icmpv6.h"
#ifdef CONFIG_NET_ICMPv6_AUTOCONF
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define CONFIG_ICMPv6_AUTOCONF_DELAYSEC \
(CONFIG_ICMPv6_AUTOCONF_DELAYMSEC / 1000)
#define CONFIG_ICMPv6_AUTOCONF_DELAYNSEC \
((CONFIG_ICMPv6_AUTOCONF_DELAYMSEC - 1000*CONFIG_ICMPv6_AUTOCONF_DELAYSEC) * 1000000)
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure holds the state of the send operation until it can be
* operated upon from the interrupt level.
*/
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 */
#ifdef CONFIG_NETDEV_MULTINIC
uint8_t snd_ifname[IFNAMSIZ]; /* Interface name */
#endif
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: icmpv6_router_interrupt
****************************************************************************/
static uint16_t icmpv6_router_interrupt(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;
nllvdbg("flags: %04x sent: %d\n", flags, state->snd_sent);
if (state)
{
#ifdef CONFIG_NETDEV_MULTINIC
/* 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;
}
#endif
/* Check if the outgoing packet is available. It may have been claimed
* by a send interrupt 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 */
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);
}
/* Make sure no additional Router Solicitation overwrites this one.
* This flag will be cleared in icmpv6_out().
*/
IFF_SET_NOARP(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 */
sem_post(&state->snd_sem);
}
return flags;
}
/****************************************************************************
* Name: icmpv6_send_message
*
* Description:
* Send an ICMPv6 Router Solicitation to resolve an IPv6 address.
*
* 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. This is done with interrupts
* disabled
*/
(void)sem_init(&state.snd_sem, 0, 0); /* Doesn't really fail */
#ifdef CONFIG_NETDEV_MULTINIC
/* Remember the routing device name */
strncpy((FAR char *)state.snd_ifname, (FAR const char *)dev->d_ifname,
IFNAMSIZ);
#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.
*/
state.snd_cb = icmpv6_callback_alloc();
if (!state.snd_cb)
{
ndbg("ERROR: Failed to allocate a cllback\n");
ret = -ENOMEM;
goto errout_with_semaphore;
}
/* Arm the callback */
state.snd_sent = false;
state.snd_advertise = advertise;
state.snd_cb->flags = ICMPv6_POLL;
state.snd_cb->priv = (FAR void *)&state;
state.snd_cb->event = icmpv6_router_interrupt;
/* Notify the device driver that new TX data is available. */
dev->d_txavail(dev);
/* Wait for the send to complete or an error to occur: NOTES: (1)
* net_lockedwait will also terminate if a signal is received, (2)
* interrupts may be disabled! They will be re-enabled while the
* task sleeps and automatically re-enabled when the task restarts.
*/
do
{
(void)net_lockedwait(&state.snd_sem);
}
while (!state.snd_sent);
icmpv6_callback_free(state.snd_cb);
ret = OK;
errout_with_semaphore:
sem_destroy(&state.snd_sem);
return ret;
}
/****************************************************************************
* Name: icmpv6_wait_radvertise
*
* Description:
* Wait for the receipt of the Router Advertisement matching the Router
* Solicitation that we just sent.
*
* Parameters:
* dev - The device to use to send the solicitation
* notify - The pre-initialized notification structure
* save - We will need this to temporarily release the net lock
*
* Returned Value:
* Zero (OK) is returned on success; On error a negated errno value is
* returned.
*
* Assumptions:
* The network is locked.
*
****************************************************************************/
static int icmpv6_wait_radvertise(FAR struct net_driver_s *dev,
FAR struct icmpv6_rnotify_s *notify,
net_lock_t *save)
{
struct timespec delay;
#ifdef CONFIG_NET_NOINTS
irqstate_t flags;
#endif
int ret;
/* Wait for response to the Router Advertisement to be received. The
* optimal delay would be the work case round trip time.
* NOTE: The network is locked.
*/
delay.tv_sec = CONFIG_ICMPv6_AUTOCONF_DELAYSEC;
delay.tv_nsec = CONFIG_ICMPv6_AUTOCONF_DELAYNSEC;
#ifdef CONFIG_NET_NOINTS
flags = irqsave(); /* Keep things stable */
net_unlock(*save); /* Unlock the network with interrupts disabled */
#endif
ret = icmpv6_rwait(notify, &delay);
#ifdef CONFIG_NET_NOINTS
*save = net_lock(); /* Re-lock the network with interrupts disabled */
irqrestore(flags);
#endif
/* icmpv6_wait will return OK if and only if the matching Router
* Advertisement is received. Otherwise, it will return -ETIMEDOUT.
*/
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 data 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.
*
* Parameters:
* dev - The device driver structure to assign the address to
*
* Return:
* Zero (OK) is returned on success; A negated errno value is returned on
* any failure.
*
****************************************************************************/
int icmpv6_autoconfig(FAR struct net_driver_s *dev)
{
#ifndef CONFIG_NET_ETHERNET
/* Only Ethernet supported for now */
ndbg("ERROR: Only Ethernet is supported\n");
return -ENOSYS;
#else /* CONFIG_NET_ETHERNET */
struct icmpv6_rnotify_s notify;
net_ipv6addr_t lladdr;
net_lock_t save;
int retries;
int ret;
/* Sanity checks */
DEBUGASSERT(dev);
nvdbg("Auto-configuring %s\n", dev->d_ifname);
#ifdef CONFIG_NET_MULTILINK
/* Only Ethernet devices are supported for now */
if (dev->d_lltype != NET_LL_ETHERNET)
{
ndbg("ERROR: Only Ethernet is supported\n");
return -ENOSYS;
}
#endif
/* The interface should be in the down state */
save = net_lock();
netdev_ifdown(dev);
net_unlock(save);
/* IPv6 Stateless Autoconfiguration
* Reference: http://www.tcpipguide.com/free/t_IPv6AutoconfiguratinoandRenumbering.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 data link layer (MAC) address.
*
* IEEE 802 MAC addresses, used by Ethernet and other IEEE 802 Project
* networking technologies, have 48 bits. The IEEE has also defined a
* format called the 64-bit extended unique identifier, abbreviated
* EUI-64. To get the modified EUI-64 interface ID for a device, you
* simply take the EUI-64 address and change the 7th bit from the left
* (the"universal/local" or "U/L" bit) from a zero to a one.
*
* 128 112 96 80 64 48 32 16
* ---- ---- ---- ---- ---- ---- ---- ----
* fe80 0000 0000 0000 0000 xxxx xxxx xxxx
*/
lladdr[0] = HTONS(0xfe80); /* 10-bit address + 6 zeroes */
memset(&lladdr[1], 0, 4* sizeof(uint16_t)); /* 64 more zeroes */
memcpy(&lladdr[5], dev->d_mac.ether_addr_octet,
sizeof(struct ether_addr)); /* 48-bit Ethernet address */
nvdbg("lladdr=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
lladdr[0], lladdr[1], lladdr[2], lladdr[3],
lladdr[4], lladdr[6], lladdr[6], lladdr[7]);
#ifdef CONFIG_NET_ICMPv6_NEIGHBOR
/* Bring the interface up with no IP address */
save = net_lock();
netdev_ifup(dev);
net_unlock(save);
/* 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);
/* Take the interface back down */
save = net_lock();
netdev_ifdown(dev);
net_unlock(save);
if (ret == OK)
{
/* Hmmm... someone else responded to our Neighbor Solicitation. We
* have not back-up plan in place. Just bail.
*/
ndbg("ERROR: IP conflict\n");
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).
*/
save = net_lock();
net_ipv6addr_copy(dev->d_ipv6addr, lladdr);
/* Bring the interface up with the new, temporary IP address */
netdev_ifup(dev);
/* 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)
{
ndbg("ERROR: Failed send router solicitation: %d\n", ret);
break;
}
/* Wait to receive the Router Advertisement message */
ret = icmpv6_wait_radvertise(dev, &notify, &save);
if (ret != -ETIMEDOUT)
{
/* ETIMEDOUT is the only expected failure. We will retry on that
* case only.
*/
break;
}
nvdbg("Timed out... retrying %d\n", retries + 1);
}
/* Check for failures. Note: On successful return, the network will be
* in the down state, but not in the event of failures.
*/
if (ret < 0)
{
ndbg("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.
*/
ret = icmpv6_send_message(dev, true);
if (ret < 0)
{
ndbg("ERROR: Failed send neighbor advertisement: %d\n", ret);
netdev_ifdown(dev);
}
/* Set a netmask for the local link address */
net_ipv6addr_copy(dev->d_ipv6netmask, g_ipv6_llnetmask);
/* Leave the network up and return success (even though things did not
* work out quite the way we wanted).
*/
net_unlock(save);
return ret;
}
/* 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()). We
* need only to bring the network back to the up state and return success.
*/
netdev_ifup(dev);
net_unlock(save);
return OK;
#endif /* CONFIG_NET_ETHERNET */
}
#endif /* CONFIG_NET_ICMPv6_AUTOCONF */
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