/**************************************************************************** * net/icmpv6/icmpv6_neighbor.c * * Copyright (C) 2015-2016 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include #include #include #include #include #include #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 /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ #define CONFIG_ICMPv6_NEIGHBOR_DELAYSEC \ (CONFIG_ICMPv6_NEIGHBOR_DELAYMSEC / 1000) #define CONFIG_ICMPv6_NEIGHBOR_DELAYNSEC \ ((CONFIG_ICMPv6_NEIGHBOR_DELAYMSEC - 1000*CONFIG_ICMPv6_NEIGHBOR_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_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 *pvconn, 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 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 */ icmpv6_solicit(dev, state->snd_ipaddr); /* Make sure no additional Neighbor 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 */ 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. * * 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 timespec delay; struct icmpv6_neighbor_s state; FAR const uint16_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_allzeroaddr) || (ipaddr[0] & NTOHS(0xff00)) == NTOHS(0xff00)) { /* We don't need to send the Neighbor Solicitation */ return OK; } /* Get the device that can route this request */ dev = netdev_findby_ipv6addr(g_ipv6_allzeroaddr, ipaddr); if (!dev) { nerr("ERROR: Unreachable: %08lx\n", (unsigned long)ipaddr); ret = -EHOSTUNREACH; goto errout; } /* Send the Neighbor Solicitation request only if this device uses the * Ethernet data link protocol. * * REVISIT: Other link layer protocols may require Neighbor Discovery * as well. */ if (dev->d_lltype != NET_LL_ETHERNET) { return OK; } /* 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 */ lookup = ipaddr; } else { net_ipv6addr_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_ipv6_router(dev, ipaddr, dripaddr); #else /* Use the device's default router IP address instead of the * destination address when determining the MAC address. */ net_ipv6addr_copy(dripaddr, dev->d_ipv6draddr); #endif /* Use the router address for the lookup */ lookup = dripaddr; } /* 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 = icmpv6_callback_alloc(dev); if (!state.snd_cb) { nerr("ERROR: Failed to allocate a callback\n"); ret = -ENOMEM; goto errout_with_lock; } /* Initialize the state structure. This is done with interrupts * disabled */ /* This semaphore is used for signaling and, hence, should not have * priority inheritance enabled. */ (void)nxsem_init(&state.snd_sem, 0, 0); /* Doesn't really fail */ nxsem_setprotocol(&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 */ strncpy((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_findentry(lookup) != NULL) { /* 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. */ 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); /* Now wait for response to the Neighbor 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_NEIGHBOR_DELAYSEC; delay.tv_nsec = CONFIG_ICMPv6_NEIGHBOR_DELAYNSEC; ret = icmpv6_wait(¬ify, &delay); /* 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); icmpv6_callback_free(dev, state.snd_cb); errout_with_lock: net_unlock(); errout: return ret; } #endif /* CONFIG_NET_ICMPv6_NEIGHBOR */