/**************************************************************************** * 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 #include #include #include #include #include #include #include #include #include #include "devif/devif.h" #include "netdev/netdev.h" #include "inet/inet.h" #include "icmpv6/icmpv6.h" #include "utils/utils.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 *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; } /* Prepare device buffer */ if (netdev_iob_prepare(dev, false, 0) != OK) { 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, we should * already have link-local address by previous logic. */ icmpv6_advertise(dev, netdev_ipv6_lladdr(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. */ nxsem_init(&state.snd_sem, 0, 0); /* Doesn't really fail */ /* Remember the routing device name */ strlcpy((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, &dev->d_conncb_tail); 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_sem_wait will also terminate if a signal is received. */ do { net_sem_wait(&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. */ if (netdev_ipv6_lladdr(dev) != NULL) { goto got_lladdr; } 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. */ if (dev->d_lltype == NET_LL_ETHERNET || dev->d_lltype == NET_LL_IEEE80211) { ret = icmpv6_neighbor(dev, 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). */ ret = netdev_ipv6_add(dev, lladdr, net_ipv6_mask2pref(g_ipv6_llnetmask)); if (ret < 0) { net_unlock(); return ret; } got_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, ¬ify); /* 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(¬ify, 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); } /* 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 */