3 * AutoIP Automatic LinkLocal IP Configuration
5 * This is a AutoIP implementation for the lwIP TCP/IP stack. It aims to conform
8 * @defgroup autoip AUTOIP
10 * AUTOIP related functions
13 * define @ref LWIP_AUTOIP 1 in your lwipopts.h
15 * AUTOIP_TMR_INTERVAL msecs,
16 * I recommend a value of 100. The value must divide 1000 with a remainder almost 0.
17 * Possible values are 1000, 500, 333, 250, 200, 166, 142, 125, 111, 100 ....
20 * - Call autoip_start() after netif_add().
23 * - define @ref LWIP_DHCP_AUTOIP_COOP 1 in your lwipopts.h.
24 * - Configure your DHCP Client.
26 * @see netifapi_autoip
31 * Copyright (c) 2007 Dominik Spies <kontakt@dspies.de>
32 * All rights reserved.
34 * Redistribution and use in source and binary forms, with or without modification,
35 * are permitted provided that the following conditions are met:
37 * 1. Redistributions of source code must retain the above copyright notice,
38 * this list of conditions and the following disclaimer.
39 * 2. Redistributions in binary form must reproduce the above copyright notice,
40 * this list of conditions and the following disclaimer in the documentation
41 * and/or other materials provided with the distribution.
42 * 3. The name of the author may not be used to endorse or promote products
43 * derived from this software without specific prior written permission.
45 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
46 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
47 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
48 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
49 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
50 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
51 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
52 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
53 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
56 * Author: Dominik Spies <kontakt@dspies.de>
61 #if LWIP_IPV4 && LWIP_AUTOIP /* don't build if not configured for use in lwipopts.h */
64 /* #include "lwip/udp.h" */
65 #include "lwip/ip_addr.h"
66 #include "lwip/netif.h"
67 #include "lwip/autoip.h"
68 #include "lwip/etharp.h"
69 #include "lwip/prot/autoip.h"
73 /** Pseudo random macro based on netif informations.
74 * You could use "rand()" from the C Library if you define LWIP_AUTOIP_RAND in lwipopts.h */
75 #ifndef LWIP_AUTOIP_RAND
76 #define LWIP_AUTOIP_RAND(netif) ( (((u32_t)((netif->hwaddr[5]) & 0xff) << 24) | \
77 ((u32_t)((netif->hwaddr[3]) & 0xff) << 16) | \
78 ((u32_t)((netif->hwaddr[2]) & 0xff) << 8) | \
79 ((u32_t)((netif->hwaddr[4]) & 0xff))) + \
80 (netif_autoip_data(netif)? netif_autoip_data(netif)->tried_llipaddr : 0))
81 #endif /* LWIP_AUTOIP_RAND */
84 * Macro that generates the initial IP address to be tried by AUTOIP.
85 * If you want to override this, define it to something else in lwipopts.h.
87 #ifndef LWIP_AUTOIP_CREATE_SEED_ADDR
88 #define LWIP_AUTOIP_CREATE_SEED_ADDR(netif) \
89 lwip_htonl(AUTOIP_RANGE_START + ((u32_t)(((u8_t)(netif->hwaddr[4])) | \
90 ((u32_t)((u8_t)(netif->hwaddr[5]))) << 8)))
91 #endif /* LWIP_AUTOIP_CREATE_SEED_ADDR */
93 /* static functions */
94 static err_t autoip_arp_announce(struct netif *netif);
95 static void autoip_start_probing(struct netif *netif);
99 * Set a statically allocated struct autoip to work with.
100 * Using this prevents autoip_start to allocate it using mem_malloc.
102 * @param netif the netif for which to set the struct autoip
103 * @param autoip (uninitialised) autoip struct allocated by the application
106 autoip_set_struct(struct netif *netif, struct autoip *autoip)
108 LWIP_ASSERT_CORE_LOCKED();
109 LWIP_ASSERT("netif != NULL", netif != NULL);
110 LWIP_ASSERT("autoip != NULL", autoip != NULL);
111 LWIP_ASSERT("netif already has a struct autoip set",
112 netif_autoip_data(netif) == NULL);
114 /* clear data structure */
115 memset(autoip, 0, sizeof(struct autoip));
116 /* autoip->state = AUTOIP_STATE_OFF; */
117 netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_AUTOIP, autoip);
120 /** Restart AutoIP client and check the next address (conflict detected)
122 * @param netif The netif under AutoIP control
125 autoip_restart(struct netif *netif)
127 struct autoip* autoip = netif_autoip_data(netif);
128 autoip->tried_llipaddr++;
133 * Handle a IP address conflict after an ARP conflict detection
136 autoip_handle_arp_conflict(struct netif *netif)
138 struct autoip* autoip = netif_autoip_data(netif);
140 /* RFC3927, 2.5 "Conflict Detection and Defense" allows two options where
141 a) means retreat on the first conflict and
142 b) allows to keep an already configured address when having only one
143 conflict in 10 seconds
144 We use option b) since it helps to improve the chance that one of the two
145 conflicting hosts may be able to retain its address. */
147 if (autoip->lastconflict > 0) {
148 /* retreat, there was a conflicting ARP in the last DEFEND_INTERVAL seconds */
149 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
150 ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n"));
152 /* Active TCP sessions are aborted when removing the ip addresss */
153 autoip_restart(netif);
155 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
156 ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n"));
157 autoip_arp_announce(netif);
158 autoip->lastconflict = DEFEND_INTERVAL * AUTOIP_TICKS_PER_SECOND;
163 * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255
165 * @param netif network interface on which create the IP-Address
166 * @param ipaddr ip address to initialize
169 autoip_create_addr(struct netif *netif, ip4_addr_t *ipaddr)
171 struct autoip* autoip = netif_autoip_data(netif);
173 /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255
174 * compliant to RFC 3927 Section 2.1
175 * We have 254 * 256 possibilities */
177 u32_t addr = lwip_ntohl(LWIP_AUTOIP_CREATE_SEED_ADDR(netif));
178 addr += autoip->tried_llipaddr;
179 addr = AUTOIP_NET | (addr & 0xffff);
180 /* Now, 169.254.0.0 <= addr <= 169.254.255.255 */
182 if (addr < AUTOIP_RANGE_START) {
183 addr += AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
185 if (addr > AUTOIP_RANGE_END) {
186 addr -= AUTOIP_RANGE_END - AUTOIP_RANGE_START + 1;
188 LWIP_ASSERT("AUTOIP address not in range", (addr >= AUTOIP_RANGE_START) &&
189 (addr <= AUTOIP_RANGE_END));
190 ip4_addr_set_u32(ipaddr, lwip_htonl(addr));
192 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
193 ("autoip_create_addr(): tried_llipaddr=%"U16_F", %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
194 (u16_t)(autoip->tried_llipaddr), ip4_addr1_16(ipaddr), ip4_addr2_16(ipaddr),
195 ip4_addr3_16(ipaddr), ip4_addr4_16(ipaddr)));
199 * Sends an ARP probe from a network interface
201 * @param netif network interface used to send the probe
204 autoip_arp_probe(struct netif *netif)
206 struct autoip* autoip = netif_autoip_data(netif);
207 /* this works because netif->ip_addr is ANY */
208 return etharp_request(netif, &autoip->llipaddr);
212 * Sends an ARP announce from a network interface
214 * @param netif network interface used to send the announce
217 autoip_arp_announce(struct netif *netif)
219 return etharp_gratuitous(netif);
223 * Configure interface for use with current LL IP-Address
225 * @param netif network interface to configure with current LL IP-Address
228 autoip_bind(struct netif *netif)
230 struct autoip* autoip = netif_autoip_data(netif);
231 ip4_addr_t sn_mask, gw_addr;
233 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
234 ("autoip_bind(netif=%p) %c%c%"U16_F" %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
235 (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num,
236 ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
237 ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
239 IP4_ADDR(&sn_mask, 255, 255, 0, 0);
240 IP4_ADDR(&gw_addr, 0, 0, 0, 0);
242 netif_set_addr(netif, &autoip->llipaddr, &sn_mask, &gw_addr);
243 /* interface is used by routing now that an address is set */
250 * Start AutoIP client
252 * @param netif network interface on which start the AutoIP client
255 autoip_start(struct netif *netif)
257 struct autoip* autoip = netif_autoip_data(netif);
258 err_t result = ERR_OK;
260 LWIP_ASSERT_CORE_LOCKED();
261 LWIP_ERROR("netif is not up, old style port?", netif_is_up(netif), return ERR_ARG;);
263 /* Set IP-Address, Netmask and Gateway to 0 to make sure that
264 * ARP Packets are formed correctly
266 netif_set_addr(netif, IP4_ADDR_ANY4, IP4_ADDR_ANY4, IP4_ADDR_ANY4);
268 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
269 ("autoip_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0],
270 netif->name[1], (u16_t)netif->num));
271 if (autoip == NULL) {
272 /* no AutoIP client attached yet? */
273 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
274 ("autoip_start(): starting new AUTOIP client\n"));
275 autoip = (struct autoip *)mem_malloc(sizeof(struct autoip));
276 if (autoip == NULL) {
277 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
278 ("autoip_start(): could not allocate autoip\n"));
281 memset(autoip, 0, sizeof(struct autoip));
282 /* store this AutoIP client in the netif */
283 netif_set_client_data(netif, LWIP_NETIF_CLIENT_DATA_INDEX_AUTOIP, autoip);
284 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_start(): allocated autoip"));
286 autoip->state = AUTOIP_STATE_OFF;
288 autoip->sent_num = 0;
289 ip4_addr_set_zero(&autoip->llipaddr);
290 autoip->lastconflict = 0;
293 autoip_create_addr(netif, &(autoip->llipaddr));
294 autoip_start_probing(netif);
300 autoip_start_probing(struct netif *netif)
302 struct autoip* autoip = netif_autoip_data(netif);
304 autoip->state = AUTOIP_STATE_PROBING;
305 autoip->sent_num = 0;
306 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
307 ("autoip_start_probing(): changing state to PROBING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
308 ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
309 ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
311 /* time to wait to first probe, this is randomly
312 * chosen out of 0 to PROBE_WAIT seconds.
313 * compliant to RFC 3927 Section 2.2.1
315 autoip->ttw = (u16_t)(LWIP_AUTOIP_RAND(netif) % (PROBE_WAIT * AUTOIP_TICKS_PER_SECOND));
318 * if we tried more then MAX_CONFLICTS we must limit our rate for
319 * acquiring and probing address
320 * compliant to RFC 3927 Section 2.2.1
322 if (autoip->tried_llipaddr > MAX_CONFLICTS) {
323 autoip->ttw = RATE_LIMIT_INTERVAL * AUTOIP_TICKS_PER_SECOND;
328 * Handle a possible change in the network configuration.
330 * If there is an AutoIP address configured, take the interface down
331 * and begin probing with the same address.
334 autoip_network_changed(struct netif *netif)
336 struct autoip* autoip = netif_autoip_data(netif);
338 if (autoip && (autoip->state != AUTOIP_STATE_OFF)) {
339 autoip_start_probing(netif);
347 * @param netif network interface on which stop the AutoIP client
350 autoip_stop(struct netif *netif)
352 struct autoip* autoip = netif_autoip_data(netif);
354 LWIP_ASSERT_CORE_LOCKED();
355 if (autoip != NULL) {
356 autoip->state = AUTOIP_STATE_OFF;
357 if (ip4_addr_islinklocal(netif_ip4_addr(netif))) {
358 netif_set_addr(netif, IP4_ADDR_ANY4, IP4_ADDR_ANY4, IP4_ADDR_ANY4);
365 * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds
370 struct netif *netif = netif_list;
371 /* loop through netif's */
372 while (netif != NULL) {
373 struct autoip* autoip = netif_autoip_data(netif);
374 /* only act on AutoIP configured interfaces */
375 if (autoip != NULL) {
376 if (autoip->lastconflict > 0) {
377 autoip->lastconflict--;
380 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE,
381 ("autoip_tmr() AutoIP-State: %"U16_F", ttw=%"U16_F"\n",
382 (u16_t)(autoip->state), autoip->ttw));
384 if (autoip->ttw > 0) {
388 switch(autoip->state) {
389 case AUTOIP_STATE_PROBING:
390 if (autoip->ttw == 0) {
391 if (autoip->sent_num >= PROBE_NUM) {
392 /* Switch to ANNOUNCING: now we can bind to an IP address and use it */
393 autoip->state = AUTOIP_STATE_ANNOUNCING;
395 /* autoip_bind() calls netif_set_addr(): this triggers a gratuitous ARP
396 which counts as an announcement */
397 autoip->sent_num = 1;
398 autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND;
399 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
400 ("autoip_tmr(): changing state to ANNOUNCING: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
401 ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
402 ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
404 autoip_arp_probe(netif);
405 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_tmr() PROBING Sent Probe\n"));
407 if (autoip->sent_num == PROBE_NUM) {
408 /* calculate time to wait to for announce */
409 autoip->ttw = ANNOUNCE_WAIT * AUTOIP_TICKS_PER_SECOND;
411 /* calculate time to wait to next probe */
412 autoip->ttw = (u16_t)((LWIP_AUTOIP_RAND(netif) %
413 ((PROBE_MAX - PROBE_MIN) * AUTOIP_TICKS_PER_SECOND) ) +
414 PROBE_MIN * AUTOIP_TICKS_PER_SECOND);
420 case AUTOIP_STATE_ANNOUNCING:
421 if (autoip->ttw == 0) {
422 autoip_arp_announce(netif);
423 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_tmr() ANNOUNCING Sent Announce\n"));
424 autoip->ttw = ANNOUNCE_INTERVAL * AUTOIP_TICKS_PER_SECOND;
427 if (autoip->sent_num >= ANNOUNCE_NUM) {
428 autoip->state = AUTOIP_STATE_BOUND;
429 autoip->sent_num = 0;
431 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE,
432 ("autoip_tmr(): changing state to BOUND: %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
433 ip4_addr1_16(&autoip->llipaddr), ip4_addr2_16(&autoip->llipaddr),
434 ip4_addr3_16(&autoip->llipaddr), ip4_addr4_16(&autoip->llipaddr)));
440 /* nothing to do in other states */
444 /* proceed to next network interface */
450 * Handles every incoming ARP Packet, called by etharp_input().
452 * @param netif network interface to use for autoip processing
453 * @param hdr Incoming ARP packet
456 autoip_arp_reply(struct netif *netif, struct etharp_hdr *hdr)
458 struct autoip* autoip = netif_autoip_data(netif);
460 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE, ("autoip_arp_reply()\n"));
461 if ((autoip != NULL) && (autoip->state != AUTOIP_STATE_OFF)) {
462 /* when ip.src == llipaddr && hw.src != netif->hwaddr
464 * when probing ip.dst == llipaddr && hw.src != netif->hwaddr
465 * we have a conflict and must solve it
467 ip4_addr_t sipaddr, dipaddr;
468 struct eth_addr netifaddr;
469 ETHADDR16_COPY(netifaddr.addr, netif->hwaddr);
471 /* Copy struct ip4_addr2 to aligned ip4_addr, to support compilers without
472 * structure packing (not using structure copy which breaks strict-aliasing rules).
474 IPADDR2_COPY(&sipaddr, &hdr->sipaddr);
475 IPADDR2_COPY(&dipaddr, &hdr->dipaddr);
477 if (autoip->state == AUTOIP_STATE_PROBING) {
478 /* RFC 3927 Section 2.2.1:
479 * from beginning to after ANNOUNCE_WAIT
480 * seconds we have a conflict if
481 * ip.src == llipaddr OR
482 * ip.dst == llipaddr && hw.src != own hwaddr
484 if ((ip4_addr_cmp(&sipaddr, &autoip->llipaddr)) ||
485 (ip4_addr_isany_val(sipaddr) &&
486 ip4_addr_cmp(&dipaddr, &autoip->llipaddr) &&
487 !eth_addr_cmp(&netifaddr, &hdr->shwaddr))) {
488 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
489 ("autoip_arp_reply(): Probe Conflict detected\n"));
490 autoip_restart(netif);
493 /* RFC 3927 Section 2.5:
494 * in any state we have a conflict if
495 * ip.src == llipaddr && hw.src != own hwaddr
497 if (ip4_addr_cmp(&sipaddr, &autoip->llipaddr) &&
498 !eth_addr_cmp(&netifaddr, &hdr->shwaddr)) {
499 LWIP_DEBUGF(AUTOIP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | LWIP_DBG_LEVEL_WARNING,
500 ("autoip_arp_reply(): Conflicting ARP-Packet detected\n"));
501 autoip_handle_arp_conflict(netif);
507 /** check if AutoIP supplied netif->ip_addr
509 * @param netif the netif to check
510 * @return 1 if AutoIP supplied netif->ip_addr (state BOUND or ANNOUNCING),
514 autoip_supplied_address(const struct netif *netif)
516 if ((netif != NULL) && (netif_autoip_data(netif) != NULL)) {
517 struct autoip* autoip = netif_autoip_data(netif);
518 return (autoip->state == AUTOIP_STATE_BOUND) || (autoip->state == AUTOIP_STATE_ANNOUNCING);
524 autoip_accept_packet(struct netif *netif, const ip4_addr_t *addr)
526 struct autoip* autoip = netif_autoip_data(netif);
527 return (autoip != NULL) && ip4_addr_cmp(addr, &(autoip->llipaddr));
530 #endif /* LWIP_IPV4 && LWIP_AUTOIP */