3 * AutoIP Automatic LinkLocal IP Configuration
9 * Copyright (c) 2007 Dominik Spies <kontakt@dspies.de>
10 * All rights reserved.
12 * Redistribution and use in source and binary forms, with or without modification,
13 * are permitted provided that the following conditions are met:
15 * 1. Redistributions of source code must retain the above copyright notice,
16 * this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright notice,
18 * this list of conditions and the following disclaimer in the documentation
19 * and/or other materials provided with the distribution.
20 * 3. The name of the author may not be used to endorse or promote products
21 * derived from this software without specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
24 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
25 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
26 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
27 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
28 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
31 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
34 * Author: Dominik Spies <kontakt@dspies.de>
36 * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform
40 * Please coordinate changes and requests with Dominik Spies
44 /*******************************************************************************
47 * define LWIP_AUTOIP 1 in your lwipopts.h
49 * If you don't use tcpip.c (so, don't call, you don't call tcpip_init):
50 * - First, call autoip_init().
51 * - call autoip_tmr() all AUTOIP_TMR_INTERVAL msces,
52 * that should be defined in autoip.h.
53 * I recommend a value of 100. The value must divide 1000 with a remainder almost 0.
54 * Possible values are 1000, 500, 333, 250, 200, 166, 142, 125, 111, 100 ....
57 * - Call autoip_start() after netif_add().
60 * - define LWIP_DHCP_AUTOIP_COOP 1 in your lwipopts.h.
61 * - Configure your DHCP Client.
67 #if LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */
71 #include "lwip/ip_addr.h"
72 #include "lwip/netif.h"
73 #include "lwip/autoip.h"
74 #include "netif/etharp.h"
80 #define AUTOIP_NET 0xA9FE0000
82 #define AUTOIP_RANGE_START (AUTOIP_NET | 0x0100)
84 #define AUTOIP_RANGE_END (AUTOIP_NET | 0xFEFF)
87 /** Pseudo random macro based on netif informations.
88 * You could use "rand()" from the C Library if you define LWIP_AUTOIP_RAND in lwipopts.h */
89 #ifndef LWIP_AUTOIP_RAND
90 #define LWIP_AUTOIP_RAND(netif) ( (((u32_t)((netif->hwaddr[5]) & 0xff) << 24) | \
91 ((u32_t)((netif->hwaddr[3]) & 0xff) << 16) | \
92 ((u32_t)((netif->hwaddr[2]) & 0xff) << 8) | \
93 ((u32_t)((netif->hwaddr[4]) & 0xff))) + \
94 (netif->autoip?netif->autoip->tried_llipaddr:0))
95 #endif /* LWIP_AUTOIP_RAND */
98 * Macro that generates the initial IP address to be tried by AUTOIP.
99 * If you want to override this, define it to something else in lwipopts.h.
101 #ifndef LWIP_AUTOIP_CREATE_SEED_ADDR
102 #define LWIP_AUTOIP_CREATE_SEED_ADDR(netif) \
103 htonl(AUTOIP_RANGE_START + ((u32_t)(((u8_t)(netif->hwaddr[4])) | \
104 ((u32_t)((u8_t)(netif->hwaddr[5]))) << 8)))
105 #endif /* LWIP_AUTOIP_CREATE_SEED_ADDR */
107 /* static functions */
108 static void autoip_handle_arp_conflict(struct netif *netif);
110 /* creates a pseudo random LL IP-Address for a network interface */
111 static void autoip_create_addr(struct netif *netif, ip_addr_t *ipaddr);
113 /* sends an ARP probe */
114 static err_t autoip_arp_probe(struct netif *netif);
116 /* sends an ARP announce */
117 static err_t autoip_arp_announce(struct netif *netif);
119 /* configure interface for use with current LL IP-Address */
120 static err_t autoip_bind(struct netif *netif);
122 /* start sending probes for llipaddr */
123 static void autoip_start_probing(struct netif *netif);
126 * Initialize this module
131 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_init()\n"));
134 /** Set a statically allocated struct autoip to work with.
135 * Using this prevents autoip_start to allocate it using mem_malloc.
137 * @param netif the netif for which to set the struct autoip
138 * @param dhcp (uninitialised) dhcp struct allocated by the application
141 autoip_set_struct(struct netif *netif, struct autoip *autoip)
143 LWIP_ASSERT("netif != NULL", netif != NULL);
144 LWIP_ASSERT("autoip != NULL", autoip != NULL);
145 LWIP_ASSERT("netif already has a struct autoip set", netif->autoip == NULL);
147 /* clear data structure */
148 memset(autoip, 0, sizeof(struct autoip));
149 /* autoip->state = AUTOIP_STATE_OFF; */
150 netif->autoip = autoip;
154 * Handle a IP address conflict after an ARP conflict detection
157 autoip_handle_arp_conflict(struct netif *netif)
159 /* Somehow detect if we are defending or retreating */
160 unsigned char defend = 1; /* tbd */
163 if(netif->autoip->lastconflict > 0) {
164 /* retreat, there was a conflicting ARP in the last
165 * DEFEND_INTERVAL seconds
167 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
168 ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n"));
170 /* TODO: close all TCP sessions */
173 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
174 ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n"));
175 autoip_arp_announce(netif);
176 netif->autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND;
179 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
180 ("autoip_handle_arp_conflict(): we do not defend, retreating\n"));
181 /* TODO: close all TCP sessions */
187 * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255
189 * @param netif network interface on which create the IP-Address
190 * @param ipaddr ip address to initialize
193 autoip_create_addr(struct netif *netif, ip_addr_t *ipaddr)
195 /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255
196 * compliant to RFC 3927 Section 2.1
197 * We have 254 * 256 possibilities */
199 u32_t addr = ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif));
200 addr += netif->autoip->tried_llipaddr;
201 addr = AUTOIP_NET | (addr & 0xffff);
202 /* Now, 169.254.0.0 <= addr <= 169.254.255.255 */
204 if (addr < AUTOIP_RANGE_START) {
205 addr += AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
207 if (addr > AUTOIP_RANGE_END) {
208 addr -= AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
210 LWIP_ASSERT("AUTOIP address not in range", (addr >= AUTOIP_RANGE_START) &&
211 (addr <= AUTOIP_RANGE_END));
212 ip4_addr_set_u32(ipaddr, htonl(addr));
214 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
215 ("autoip_create_addr(): tried_llipaddr=%"U16_F", %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
216 (u16_t)(netif->autoip->tried_llipaddr), ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr),
217 ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
221 * Sends an ARP probe from a network interface
223 * @param netif network interface used to send the probe
226 autoip_arp_probe(struct netif *netif)
228 return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast,
229 (struct eth_addr *)netif->hwaddr, IP_ADDR_ANY, ðzero,
230 &netif->autoip->llipaddr, ARP_REQUEST);
234 * Sends an ARP announce from a network interface
236 * @param netif network interface used to send the announce
239 autoip_arp_announce(struct netif *netif)
241 return etharp_raw(netif, (struct eth_addr *)netif->hwaddr, ðbroadcast,
242 (struct eth_addr *)netif->hwaddr, &netif->autoip->llipaddr, ðzero,
243 &netif->autoip->llipaddr, ARP_REQUEST);
247 * Configure interface for use with current LL IP-Address
249 * @param netif network interface to configure with current LL IP-Address
252 autoip_bind(struct netif *netif)
254 struct autoip *autoip = netif->autoip;
255 ip_addr_t sn_mask, gw_addr;
257 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
258 ("autoip_bind(netif=%p) %c%c%"U16_F" %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
259 (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num,
260 ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
261 ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
263 IP4_ADDR(&sn_mask, 255, 255, 0, 0);
264 IP4_ADDR(&gw_addr, 0, 0, 0, 0);
266 netif_set_ipaddr(netif, &autoip->llipaddr);
267 netif_set_netmask(netif, &sn_mask);
268 netif_set_gw(netif, &gw_addr);
270 /* bring the interface up */
277 * Start AutoIP client
279 * @param netif network interface on which start the AutoIP client
282 autoip_start(struct netif *netif)
284 struct autoip *autoip = netif->autoip;
285 err_t result = ERR_OK;
287 if(netif_is_up(netif)) {
288 netif_set_down(netif);
291 /* Set IP-Address, Netmask and Gateway to 0 to make sure that
292 * ARP Packets are formed correctly
294 ip_addr_set_zero(&netif->ip_addr);
295 ip_addr_set_zero(&netif->netmask);
296 ip_addr_set_zero(&netif->gw);
298 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
299 ("autoip_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0],
300 netif->name[1], (u16_t)netif->num));
302 /* no AutoIP client attached yet? */
303 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
304 ("autoip_start(): starting new AUTOIP client\n"));
305 autoip = (struct autoip *)mem_malloc(sizeof(struct autoip));
307 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
308 ("autoip_start(): could not allocate autoip\n"));
311 memset( autoip, 0, sizeof(struct autoip));
312 /* store this AutoIP client in the netif */
313 netif->autoip = autoip;
314 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip"));
316 autoip->state = AUTOIP_STATE_OFF;
318 autoip->sent_num = 0;
319 memset(&autoip->llipaddr, 0, sizeof(ip_addr_t));
320 autoip->lastconflict = 0;
323 autoip_create_addr(netif, &(autoip->llipaddr));
324 autoip->tried_llipaddr++;
325 autoip_start_probing(netif);
331 autoip_start_probing(struct netif *netif)
333 struct autoip *autoip = netif->autoip;
335 autoip->state = AUTOIP_STATE_PROBING;
336 autoip->sent_num = 0;
337 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
338 ("autoip_start_probing(): changing state to PROBING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
339 ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
340 ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
342 /* time to wait to first probe, this is randomly
343 * choosen out of 0 to PROBE_WAIT seconds.
344 * compliant to RFC 3927 Section 2.2.1
346 autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND));
349 * if we tried more then MAX_CONFLICTS we must limit our rate for
350 * accquiring and probing address
351 * compliant to RFC 3927 Section 2.2.1
353 if(autoip->tried_llipaddr > MAX_CONFLICTS) {
354 autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND;
359 * Handle a possible change in the network configuration.
361 * If there is an AutoIP address configured, take the interface down
362 * and begin probing with the same address.
365 autoip_network_changed(struct netif *netif)
367 if (netif->autoip && netif->autoip->state != AUTOIP_STATE_OFF) {
368 netif_set_down(netif);
369 autoip_start_probing(netif);
376 * @param netif network interface on which stop the AutoIP client
379 autoip_stop(struct netif *netif)
381 netif->autoip->state = AUTOIP_STATE_OFF;
382 netif_set_down(netif);
387 * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds
392 struct netif *netif = netif_list;
393 /* loop through netif's */
394 while (netif != NULL) {
395 /* only act on AutoIP configured interfaces */
396 if (netif->autoip != NULL) {
397 if(netif->autoip->lastconflict > 0) {
398 netif->autoip->lastconflict--;
401 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
402 ("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n",
403 (u16_t)(netif->autoip->state), netif->autoip->ttw));
405 switch(netif->autoip->state) {
406 case AUTOIP_STATE_PROBING:
407 if(netif->autoip->ttw > 0) {
408 netif->autoip->ttw--;
410 if(netif->autoip->sent_num >= PROBE_NUM) {
411 netif->autoip->state = AUTOIP_STATE_ANNOUNCING;
412 netif->autoip->sent_num = 0;
413 netif->autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND;
414 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
415 ("autoip_tmr(): changing state to ANNOUNCING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
416 ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
417 ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
419 autoip_arp_probe(netif);
420 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
421 ("autoip_tmr() PROBING Sent Probe\n"));
422 netif->autoip->sent_num++;
423 /* calculate time to wait to next probe */
424 netif->autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) %
425 ((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) +
426 PROBE_MIN * AUTOIP_TICKS_PER_SECOND);
431 case AUTOIP_STATE_ANNOUNCING:
432 if(netif->autoip->ttw > 0) {
433 netif->autoip->ttw--;
435 if(netif->autoip->sent_num == 0) {
436 /* We are here the first time, so we waited ANNOUNCE_WAIT seconds
437 * Now we can bind to an IP address and use it.
439 * autoip_bind calls netif_set_up. This triggers a gratuitous ARP
440 * which counts as an announcement.
444 autoip_arp_announce(netif);
445 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
446 ("autoip_tmr() ANNOUNCING Sent Announce\n"));
448 netif->autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND;
449 netif->autoip->sent_num++;
451 if(netif->autoip->sent_num >= ANNOUNCE_NUM) {
452 netif->autoip->state = AUTOIP_STATE_BOUND;
453 netif->autoip->sent_num = 0;
454 netif->autoip->ttw = 0;
455 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
456 ("autoip_tmr(): changing state to BOUND: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
457 ip4_addr1_16(&netif->autoip->llipaddr), ip4_addr2_16(&netif->autoip->llipaddr),
458 ip4_addr3_16(&netif->autoip->llipaddr), ip4_addr4_16(&netif->autoip->llipaddr)));
464 /* proceed to next network interface */
470 * Handles every incoming ARP Packet, called by etharp_arp_input.
472 * @param netif network interface to use for autoip processing
473 * @param hdr Incoming ARP packet
476 autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr)
478 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_arp_reply()\n"));
479 if ((netif->autoip != NULL) && (netif->autoip->state != AUTOIP_STATE_OFF)) {
480 /* when ip.src == llipaddr && hw.src != netif->hwaddr
482 * when probing ip.dst == llipaddr && hw.src != netif->hwaddr
483 * we have a conflict and must solve it
485 ip_addr_t sipaddr, dipaddr;
486 struct eth_addr netifaddr;
487 netifaddr.addr[0] = netif->hwaddr[0];
488 netifaddr.addr[1] = netif->hwaddr[1];
489 netifaddr.addr[2] = netif->hwaddr[2];
490 netifaddr.addr[3] = netif->hwaddr[3];
491 netifaddr.addr[4] = netif->hwaddr[4];
492 netifaddr.addr[5] = netif->hwaddr[5];
494 /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
495 * structure packing (not using structure copy which breaks strict-aliasing rules).
497 IPADDR2_COPY(&sipaddr, &hdr->sipaddr);
498 IPADDR2_COPY(&dipaddr, &hdr->dipaddr);
500 if ((netif->autoip->state == AUTOIP_STATE_PROBING) ||
501 ((netif->autoip->state == AUTOIP_STATE_ANNOUNCING) &&
502 (netif->autoip->sent_num == 0))) {
503 /* RFC 3927 Section 2.2.1:
504 * from beginning to after ANNOUNCE_WAIT
505 * seconds we have a conflict if
506 * ip.src == llipaddr OR
507 * ip.dst == llipaddr && hw.src != own hwaddr
509 if ((ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr)) ||
510 (ip_addr_cmp(&dipaddr, &netif->autoip->llipaddr) &&
511 !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) {
512 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
513 ("autoip_arp_reply(): Probe Conflict detected\n"));
517 /* RFC 3927 Section 2.5:
518 * in any state we have a conflict if
519 * ip.src == llipaddr && hw.src != own hwaddr
521 if (ip_addr_cmp(&sipaddr, &netif->autoip->llipaddr) &&
522 !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) {
523 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
524 ("autoip_arp_reply(): Conflicting ARP-Packet detected\n"));
525 autoip_handle_arp_conflict(netif);
531 #endif /* LWIP_AUTOIP */