/** * @file * AutoIP Automatic LinkLocal IP Configuration * */ /* * * Copyright (c) 2007 Dominik Spies * All rights reserved. * * 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. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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. * * Author: Dominik Spies * * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform * with RFC 3927. * * * Please coordinate changes and requests with Dominik Spies * */ /******************************************************************************* * USAGE: * * define LWIP_AUTOIP 1 in your lwipopts.h * * If you don't use tcpip.c (so, don't call, you don't call tcpip_init): * - First, call autoip_init(). * - call autoip_tmr() all AUTOIP_TMR_INTERVAL msces, * that should be defined in autoip.h. * I recommend a value of 100. The value must divide 1000 with a remainder almost 0. * Possible values are 1000, 500, 333, 250, 200, 166, 142, 125, 111, 100 .... * * Without DHCP: * - Call autoip_start() after netif_add(). * * With DHCP: * - define LWIP_DHCP_AUTOIP_COOP 1 in your lwipopts.h. * - Configure your DHCP Client. * */ #include "lwip/opt.h" #if LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */ #include "lwip/mem.h" #include "lwip/udp.h" #include "lwip/ip_addr.h" #include "lwip/netif.h" #include "lwip/autoip.h" #include "netif/etharp.h" #include #include /* Pseudo random macro based on netif informations. * You could use "rand()" from the C Library if you define LWIP_AUTOIP_RAND in lwipopts.h */ #ifndef LWIP_AUTOIP_RAND #define LWIP_AUTOIP_RAND(netif) ( (((u32_t)((netif->hwaddr[5]) & 0xff) << 24) | \ ((u32_t)((netif->hwaddr[3]) & 0xff) << 16) | \ ((u32_t)((netif->hwaddr[2]) & 0xff) << 8) | \ ((u32_t)((netif->hwaddr[4]) & 0xff))) + \ (netif->autoip?netif->autoip->tried_llipaddr:0)) #endif /* LWIP_AUTOIP_RAND */ /* static functions */ static void autoip_handle_arp_conflict(struct netif *netif); /* creates random LL IP-Address for a network interface */ static void autoip_create_rand_addr(struct netif *netif, struct ip_addr *RandomIPAddr); /* sends an ARP announce */ static err_t autoip_arp_announce(struct netif *netif); /* configure interface for use with current LL IP-Address */ static err_t autoip_bind(struct netif *netif); /** * Initialize this module */ void autoip_init(void) { LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, ("autoip_init()\n")); } /** * Handle a IP address conflict after an ARP conflict detection */ static void autoip_handle_arp_conflict(struct netif *netif) { /* Somehow detect if we are defending or retreating */ unsigned char defend = 1; /* tbd */ if(defend) { if(netif->autoip->lastconflict > 0) { /* retreat, there was a conflicting ARP in the last * DEFEND_INTERVAL seconds */ LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n")); /* TODO: close all TCP sessions */ autoip_start(netif); } else { LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n")); autoip_arp_announce(netif); netif->autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND; } } else { LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, ("autoip_handle_arp_conflict(): we do not defend, retreating\n")); /* TODO: close all TCP sessions */ autoip_start(netif); } } /** * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255 * * @param netif network interface on which create the IP-Address * @param RandomIPAddr ip address to initialize */ static void autoip_create_rand_addr(struct netif *netif, struct ip_addr *RandomIPAddr) { /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255 * compliant to RFC 3927 Section 2.1 * We have 254 * 256 possibilities */ RandomIPAddr->addr = (0xA9FE0100 + ((u32_t)(((u8_t)(netif->hwaddr[4])) | ((u32_t)((u8_t)(netif->hwaddr[5]))) << 8)) + netif->autoip->tried_llipaddr); if (RandomIPAddr->addr>0xA9FEFEFF) { RandomIPAddr->addr = (0xA9FE0100 + (RandomIPAddr->addr-0xA9FEFEFF)); } if (RandomIPAddr->addr<0xA9FE0100) { RandomIPAddr->addr = (0xA9FEFEFF - (0xA9FE0100-RandomIPAddr->addr)); } RandomIPAddr->addr = htonl(RandomIPAddr->addr); LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, ("autoip_create_rand_addr(): tried_llipaddr=%"U16_F", 0x%08"X32_F"\n", (u16_t)(netif->autoip->tried_llipaddr), (u32_t)(RandomIPAddr->addr))); } /** * Sends an ARP announce from a network interface * * @param netif network interface used to send the announce */ static err_t autoip_arp_announce(struct netif *netif) { return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast, (struct eth_addr *)netif->hwaddr, &netif->autoip->llipaddr, ðzero, &netif->autoip->llipaddr, ARP_REQUEST); } /** * Configure interface for use with current LL IP-Address * * @param netif network interface to configure with current LL IP-Address */ static err_t autoip_bind(struct netif *netif) { struct autoip *autoip = netif->autoip; struct ip_addr sn_mask, gw_addr; LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, ("autoip_bind(netif=%p) %c%c%"U16_F" 0x%08"X32_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num, autoip->llipaddr.addr)); IP4_ADDR(&sn_mask, 255, 255, 0, 0); IP4_ADDR(&gw_addr, 0, 0, 0, 0); netif_set_ipaddr(netif, &autoip->llipaddr); netif_set_netmask(netif, &sn_mask); netif_set_gw(netif, &gw_addr); /* bring the interface up */ netif_set_up(netif); return ERR_OK; } /** * Start AutoIP client * * @param netif network interface on which start the AutoIP client */ err_t autoip_start(struct netif *netif) { struct autoip *autoip = netif->autoip; err_t result = ERR_OK; if(netif_is_up(netif)) { netif_set_down(netif); } /* Set IP-Address, Netmask and Gateway to 0 to make sure that * ARP Packets are formed correctly */ netif->ip_addr.addr = 0; netif->netmask.addr = 0; netif->gw.addr = 0; LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("autoip_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num)); if(autoip == NULL) { /* no AutoIP client attached yet? */ LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): starting new AUTOIP client\n")); autoip = mem_malloc(sizeof(struct autoip)); if(autoip == NULL) { LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): could not allocate autoip\n")); return ERR_MEM; } memset( autoip, 0, sizeof(struct autoip)); /* store this AutoIP client in the netif */ netif->autoip = autoip; LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip")); } else { autoip->state = AUTOIP_STATE_OFF; autoip->ttw = 0; autoip->sent_num = 0; memset(&autoip->llipaddr, 0, sizeof(struct ip_addr)); autoip->lastconflict = 0; } autoip_create_rand_addr(netif, &(autoip->llipaddr)); autoip->tried_llipaddr++; autoip->state = AUTOIP_STATE_PROBING; autoip->sent_num = 0; /* time to wait to first probe, this is randomly * choosen out of 0 to PROBE_WAIT seconds. * compliant to RFC 3927 Section 2.2.1 */ autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND)); /* * if we tried more then MAX_CONFLICTS we must limit our rate for * accquiring and probing address * compliant to RFC 3927 Section 2.2.1 */ if(autoip->tried_llipaddr > MAX_CONFLICTS) { autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND; } return result; } /** * Stop AutoIP client * * @param netif network interface on which stop the AutoIP client */ err_t autoip_stop(struct netif *netif) { netif->autoip->state = AUTOIP_STATE_OFF; netif_set_down(netif); return ERR_OK; } /** * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds */ void autoip_tmr() { struct netif *netif = netif_list; /* loop through netif's */ while (netif != NULL) { /* only act on AutoIP configured interfaces */ if (netif->autoip != NULL) { if(netif->autoip->lastconflict > 0) { netif->autoip->lastconflict--; } LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n", (u16_t)(netif->autoip->state), netif->autoip->ttw)); switch(netif->autoip->state) { case AUTOIP_STATE_PROBING: if(netif->autoip->ttw > 0) { netif->autoip->ttw--; } else { if(netif->autoip->sent_num == PROBE_NUM) { netif->autoip->state = AUTOIP_STATE_ANNOUNCING; netif->autoip->sent_num = 0; netif->autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND; } else { etharp_request(netif, &(netif->autoip->llipaddr)); LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, ("autoip_tmr() PROBING Sent Probe\n")); netif->autoip->sent_num++; /* calculate time to wait to next probe */ netif->autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) % ((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) + PROBE_MIN * AUTOIP_TICKS_PER_SECOND); } } break; case AUTOIP_STATE_ANNOUNCING: if(netif->autoip->ttw > 0) { netif->autoip->ttw--; } else { if(netif->autoip->sent_num == 0) { /* We are here the first time, so we waited ANNOUNCE_WAIT seconds * Now we can bind to an IP address and use it */ autoip_bind(netif); } if(netif->autoip->sent_num == ANNOUNCE_NUM) { netif->autoip->state = AUTOIP_STATE_BOUND; netif->autoip->sent_num = 0; netif->autoip->ttw = 0; } else { autoip_arp_announce(netif); LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, ("autoip_tmr() ANNOUNCING Sent Announce\n")); netif->autoip->sent_num++; netif->autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND; } } break; } } /* proceed to next network interface */ netif = netif->next; } } /** * Handles every incoming ARP Packet, called by etharp_arp_input. * * @param netif network interface to use for autoip processing * @param hdr Incoming ARP packet */ void autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr) { LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | 3, ("autoip_arp_reply()\n")); if ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) { /* when ip.src == llipaddr && hw.src != netif->hwaddr * * when probing ip.dst == llipaddr && hw.src != netif->hwaddr * we have a conflict and must solve it */ struct ip_addr sipaddr, dipaddr; struct eth_addr netifaddr; netifaddr.addr[0] = netif->hwaddr[0]; netifaddr.addr[1] = netif->hwaddr[1]; netifaddr.addr[2] = netif->hwaddr[2]; netifaddr.addr[3] = netif->hwaddr[3]; netifaddr.addr[4] = netif->hwaddr[4]; netifaddr.addr[5] = netif->hwaddr[5]; /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without * structure packing (not using structure copy which breaks strict-aliasing rules). */ MEMCPY(&sipaddr, &hdr->sipaddr, sizeof(sipaddr)); MEMCPY(&dipaddr, &hdr->dipaddr, sizeof(dipaddr)); if ((netif->autoip->state == AUTOIP_STATE_PROBING) || ((netif->autoip->state == AUTOIP_STATE_ANNOUNCING) && (netif->autoip->sent_num == 0))) { /* RFC 3927 Section 2.2.1: * from beginning to after ANNOUNCE_WAIT * seconds we have a conflict if * ip.src == llipaddr OR * ip.dst == llipaddr && hw.src != own hwaddr */ if ((ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr)) || (ip_addr_cmp(&dipaddr, &netif->autoip->llipaddr) && !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) { LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, ("autoip_arp_reply(): Probe Conflict detected\n")); autoip_start(netif); } } else { /* RFC 3927 Section 2.5: * in any state we have a conflict if * ip.src == llipaddr && hw.src != own hwaddr */ if (ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr) && !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) { LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, ("autoip_arp_reply(): Conflicting ARP-Packet detected\n")); autoip_handle_arp_conflict(netif); } } } } #endif /* LWIP_AUTOIP */