/**************************************************************************** * net/icmpv6/icmpv6_autoconfig.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 "devif/devif.h" #include "netdev/netdev.h" #include "inet/inet.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 */ 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 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. */ 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); } /* 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. */ icmpv6_router_terminate(state, OK); } 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 */ /* 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); /* 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 = icmpv6_callback_alloc(dev); 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. */ 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); ret = state.snd_result; icmpv6_callback_free(dev, state.snd_cb); errout_with_semaphore: nxsem_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 * * 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) { struct timespec delay; 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; ret = icmpv6_rwait(notify, &delay); /* 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 * * 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) { #ifndef CONFIG_NET_ETHERNET /* Only Ethernet supported for now */ nerr("ERROR: Only Ethernet is supported\n"); return -ENOSYS; #else /* CONFIG_NET_ETHERNET */ 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); /* Only Ethernet devices are supported for now */ if (dev->d_lltype != NET_LL_ETHERNET) { nerr("ERROR: Only Ethernet is supported\n"); return -ENOSYS; } /* The interface should be in the down state */ net_lock(); netdev_ifdown(dev); net_unlock(); /* 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 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.ether_addr_octet, sizeof(struct ether_addr)); /* 48-bit Ethernet address */ ninfo("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 */ net_lock(); netdev_ifup(dev); net_unlock(); /* 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 */ net_lock(); netdev_ifdown(dev); net_unlock(); if (ret == OK) { /* Hmmm... someone else responded to our Neighbor Solicitation. We * have not back-up plan in place. Just bail. */ nerr("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). */ 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, ¬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_wait_radvertise(dev, ¬ify); 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. Note: On successful return, the network will be * in the down state, but not in the event of failures. */ if (ret < 0) { 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. */ ret = icmpv6_send_message(dev, true); if (ret < 0) { nerr("ERROR: Failed send neighbor advertisement: %d\n", ret); netdev_ifdown(dev); } /* No off-link communications; No router address. */ net_ipv6addr_copy(dev->d_ipv6draddr, g_ipv6_allzeroaddr); /* 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(); 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(); return OK; #endif /* CONFIG_NET_ETHERNET */ } #endif /* CONFIG_NET_ICMPv6_AUTOCONF */