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"
79 /* Pseudo random macro based on netif informations.
80 * You could use "rand()" from the C Library if you define LWIP_AUTOIP_RAND in lwipopts.h */
81 #ifndef LWIP_AUTOIP_RAND
82 #define LWIP_AUTOIP_RAND(netif) ( (((u32_t)((netif->hwaddr[5]) & 0xff) << 24) | \
83 ((u32_t)((netif->hwaddr[3]) & 0xff) << 16) | \
84 ((u32_t)((netif->hwaddr[2]) & 0xff) << 8) | \
85 ((u32_t)((netif->hwaddr[4]) & 0xff))) + \
86 (netif->autoip?netif->autoip->tried_llipaddr:0))
87 #endif /* LWIP_AUTOIP_RAND */
89 /* static functions */
90 static void autoip_handle_arp_conflict(struct netif
*netif
);
92 /* creates random LL IP-Address for a network interface */
93 static void autoip_create_rand_addr(struct netif
*netif
, struct ip_addr
*RandomIPAddr
);
95 /* sends an ARP announce */
96 static err_t
autoip_arp_announce(struct netif
*netif
);
98 /* configure interface for use with current LL IP-Address */
99 static err_t
autoip_bind(struct netif
*netif
);
102 * Initialize this module
107 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| 3, ("autoip_init()\n"));
111 * Handle a IP address conflict after an ARP conflict detection
114 autoip_handle_arp_conflict(struct netif
*netif
)
116 /* Somehow detect if we are defending or retreating */
117 unsigned char defend
= 1; /* tbd */
120 if(netif
->autoip
->lastconflict
> 0) {
121 /* retreat, there was a conflicting ARP in the last
122 * DEFEND_INTERVAL seconds
124 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| LWIP_DBG_STATE
| 1,
125 ("autoip_handle_arp_conflict(): we are defending, but in DEFEND_INTERVAL, retreating\n"));
127 /* TODO: close all TCP sessions */
130 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| LWIP_DBG_STATE
| 1,
131 ("autoip_handle_arp_conflict(): we are defend, send ARP Announce\n"));
132 autoip_arp_announce(netif
);
133 netif
->autoip
->lastconflict
= DEFEND_INTERVAL
* AUTOIP_TICKS_PER_SECOND
;
136 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| LWIP_DBG_STATE
| 1,
137 ("autoip_handle_arp_conflict(): we do not defend, retreating\n"));
138 /* TODO: close all TCP sessions */
144 * Create an IP-Address out of range 169.254.1.0 to 169.254.254.255
146 * @param netif network interface on which create the IP-Address
147 * @param RandomIPAddr ip address to initialize
150 autoip_create_rand_addr(struct netif
*netif
, struct ip_addr
*RandomIPAddr
)
152 /* Here we create an IP-Address out of range 169.254.1.0 to 169.254.254.255
153 * compliant to RFC 3927 Section 2.1
154 * We have 254 * 256 possibilities
157 RandomIPAddr
->addr
= (0xA9FE0100 + ((u32_t
)(((u8_t
)(netif
->hwaddr
[4])) |
158 ((u32_t
)((u8_t
)(netif
->hwaddr
[5]))) << 8)) + netif
->autoip
->tried_llipaddr
);
160 if (RandomIPAddr
->addr
>0xA9FEFEFF) {
161 RandomIPAddr
->addr
= (0xA9FE0100 + (RandomIPAddr
->addr
-0xA9FEFEFF));
163 if (RandomIPAddr
->addr
<0xA9FE0100) {
164 RandomIPAddr
->addr
= (0xA9FEFEFF - (0xA9FE0100-RandomIPAddr
->addr
));
166 RandomIPAddr
->addr
= htonl(RandomIPAddr
->addr
);
168 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| LWIP_DBG_STATE
| 1,
169 ("autoip_create_rand_addr(): tried_llipaddr=%"U16_F
", 0x%08"X32_F
"\n",
170 (u16_t
)(netif
->autoip
->tried_llipaddr
), (u32_t
)(RandomIPAddr
->addr
)));
174 * Sends an ARP announce from a network interface
176 * @param netif network interface used to send the announce
179 autoip_arp_announce(struct netif
*netif
)
181 return etharp_raw(netif
, (struct eth_addr
*)netif
->hwaddr
, ðbroadcast
,
182 (struct eth_addr
*)netif
->hwaddr
, &netif
->autoip
->llipaddr
, ðzero
,
183 &netif
->autoip
->llipaddr
, ARP_REQUEST
);
187 * Configure interface for use with current LL IP-Address
189 * @param netif network interface to configure with current LL IP-Address
192 autoip_bind(struct netif
*netif
)
194 struct autoip
*autoip
= netif
->autoip
;
195 struct ip_addr sn_mask
, gw_addr
;
197 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| 3,
198 ("autoip_bind(netif=%p) %c%c%"U16_F
" 0x%08"X32_F
"\n",
199 (void*)netif
, netif
->name
[0], netif
->name
[1], (u16_t
)netif
->num
, autoip
->llipaddr
.addr
));
201 IP4_ADDR(&sn_mask
, 255, 255, 0, 0);
202 IP4_ADDR(&gw_addr
, 0, 0, 0, 0);
204 netif_set_ipaddr(netif
, &autoip
->llipaddr
);
205 netif_set_netmask(netif
, &sn_mask
);
206 netif_set_gw(netif
, &gw_addr
);
208 /* bring the interface up */
215 * Start AutoIP client
217 * @param netif network interface on which start the AutoIP client
220 autoip_start(struct netif
*netif
)
222 struct autoip
*autoip
= netif
->autoip
;
223 err_t result
= ERR_OK
;
225 if(netif_is_up(netif
)) {
226 netif_set_down(netif
);
229 /* Set IP-Address, Netmask and Gateway to 0 to make sure that
230 * ARP Packets are formed correctly
232 netif
->ip_addr
.addr
= 0;
233 netif
->netmask
.addr
= 0;
236 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| LWIP_DBG_STATE
,
237 ("autoip_start(netif=%p) %c%c%"U16_F
"\n", (void*)netif
, netif
->name
[0],
238 netif
->name
[1], (u16_t
)netif
->num
));
240 /* no AutoIP client attached yet? */
241 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
,
242 ("autoip_start(): starting new AUTOIP client\n"));
243 autoip
= mem_malloc(sizeof(struct autoip
));
245 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
,
246 ("autoip_start(): could not allocate autoip\n"));
249 memset( autoip
, 0, sizeof(struct autoip
));
250 /* store this AutoIP client in the netif */
251 netif
->autoip
= autoip
;
252 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
, ("autoip_start(): allocated autoip"));
254 autoip
->state
= AUTOIP_STATE_OFF
;
256 autoip
->sent_num
= 0;
257 memset(&autoip
->llipaddr
, 0, sizeof(struct ip_addr
));
258 autoip
->lastconflict
= 0;
261 autoip_create_rand_addr(netif
, &(autoip
->llipaddr
));
262 autoip
->tried_llipaddr
++;
263 autoip
->state
= AUTOIP_STATE_PROBING
;
264 autoip
->sent_num
= 0;
266 /* time to wait to first probe, this is randomly
267 * choosen out of 0 to PROBE_WAIT seconds.
268 * compliant to RFC 3927 Section 2.2.1
270 autoip
->ttw
= (u16_t
)(LWIP_AUTOIP_RAND(netif
) % (PROBE_WAIT
* AUTOIP_TICKS_PER_SECOND
));
273 * if we tried more then MAX_CONFLICTS we must limit our rate for
274 * accquiring and probing address
275 * compliant to RFC 3927 Section 2.2.1
278 if(autoip
->tried_llipaddr
> MAX_CONFLICTS
) {
279 autoip
->ttw
= RATE_LIMIT_INTERVAL
* AUTOIP_TICKS_PER_SECOND
;
288 * @param netif network interface on which stop the AutoIP client
291 autoip_stop(struct netif
*netif
)
293 netif
->autoip
->state
= AUTOIP_STATE_OFF
;
294 netif_set_down(netif
);
299 * Has to be called in loop every AUTOIP_TMR_INTERVAL milliseconds
304 struct netif
*netif
= netif_list
;
305 /* loop through netif's */
306 while (netif
!= NULL
) {
307 /* only act on AutoIP configured interfaces */
308 if (netif
->autoip
!= NULL
) {
309 if(netif
->autoip
->lastconflict
> 0) {
310 netif
->autoip
->lastconflict
--;
313 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
,
314 ("autoip_tmr() AutoIP-State: %"U16_F
", ttw=%"U16_F
"\n",
315 (u16_t
)(netif
->autoip
->state
), netif
->autoip
->ttw
));
317 switch(netif
->autoip
->state
) {
318 case AUTOIP_STATE_PROBING
:
319 if(netif
->autoip
->ttw
> 0) {
320 netif
->autoip
->ttw
--;
322 if(netif
->autoip
->sent_num
== PROBE_NUM
) {
323 netif
->autoip
->state
= AUTOIP_STATE_ANNOUNCING
;
324 netif
->autoip
->sent_num
= 0;
325 netif
->autoip
->ttw
= ANNOUNCE_WAIT
* AUTOIP_TICKS_PER_SECOND
;
327 etharp_request(netif
, &(netif
->autoip
->llipaddr
));
328 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| 3,
329 ("autoip_tmr() PROBING Sent Probe\n"));
330 netif
->autoip
->sent_num
++;
331 /* calculate time to wait to next probe */
332 netif
->autoip
->ttw
= (u16_t
)((LWIP_AUTOIP_RAND(netif
) %
333 ((PROBE_MAX
- PROBE_MIN
) * AUTOIP_TICKS_PER_SECOND
) ) +
334 PROBE_MIN
* AUTOIP_TICKS_PER_SECOND
);
339 case AUTOIP_STATE_ANNOUNCING
:
340 if(netif
->autoip
->ttw
> 0) {
341 netif
->autoip
->ttw
--;
343 if(netif
->autoip
->sent_num
== 0) {
344 /* We are here the first time, so we waited ANNOUNCE_WAIT seconds
345 * Now we can bind to an IP address and use it
350 if(netif
->autoip
->sent_num
== ANNOUNCE_NUM
) {
351 netif
->autoip
->state
= AUTOIP_STATE_BOUND
;
352 netif
->autoip
->sent_num
= 0;
353 netif
->autoip
->ttw
= 0;
355 autoip_arp_announce(netif
);
356 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| 3,
357 ("autoip_tmr() ANNOUNCING Sent Announce\n"));
358 netif
->autoip
->sent_num
++;
359 netif
->autoip
->ttw
= ANNOUNCE_INTERVAL
* AUTOIP_TICKS_PER_SECOND
;
365 /* proceed to next network interface */
371 * Handles every incoming ARP Packet, called by etharp_arp_input.
373 * @param netif network interface to use for autoip processing
374 * @param hdr Incoming ARP packet
377 autoip_arp_reply(struct netif
*netif
, struct etharp_hdr
*hdr
)
379 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| 3, ("autoip_arp_reply()\n"));
380 if ((netif
->autoip
!= NULL
) && (netif
->autoip
->state
!= AUTOIP_STATE_OFF
)) {
381 /* when ip.src == llipaddr && hw.src != netif->hwaddr
383 * when probing ip.dst == llipaddr && hw.src != netif->hwaddr
384 * we have a conflict and must solve it
386 struct ip_addr sipaddr
, dipaddr
;
387 struct eth_addr netifaddr
;
388 netifaddr
.addr
[0] = netif
->hwaddr
[0];
389 netifaddr
.addr
[1] = netif
->hwaddr
[1];
390 netifaddr
.addr
[2] = netif
->hwaddr
[2];
391 netifaddr
.addr
[3] = netif
->hwaddr
[3];
392 netifaddr
.addr
[4] = netif
->hwaddr
[4];
393 netifaddr
.addr
[5] = netif
->hwaddr
[5];
395 /* Copy struct ip_addr2 to aligned ip_addr, to support compilers without
396 * structure packing (not using structure copy which breaks strict-aliasing rules).
398 MEMCPY(&sipaddr
, &hdr
->sipaddr
, sizeof(sipaddr
));
399 MEMCPY(&dipaddr
, &hdr
->dipaddr
, sizeof(dipaddr
));
401 if ((netif
->autoip
->state
== AUTOIP_STATE_PROBING
) ||
402 ((netif
->autoip
->state
== AUTOIP_STATE_ANNOUNCING
) &&
403 (netif
->autoip
->sent_num
== 0))) {
404 /* RFC 3927 Section 2.2.1:
405 * from beginning to after ANNOUNCE_WAIT
406 * seconds we have a conflict if
407 * ip.src == llipaddr OR
408 * ip.dst == llipaddr && hw.src != own hwaddr
410 if ((ip_addr_cmp(&sipaddr
, &netif
->autoip
->llipaddr
)) ||
411 (ip_addr_cmp(&dipaddr
, &netif
->autoip
->llipaddr
) &&
412 !eth_addr_cmp(&netifaddr
, &hdr
->shwaddr
))) {
413 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| LWIP_DBG_STATE
| 1,
414 ("autoip_arp_reply(): Probe Conflict detected\n"));
418 /* RFC 3927 Section 2.5:
419 * in any state we have a conflict if
420 * ip.src == llipaddr && hw.src != own hwaddr
422 if (ip_addr_cmp(&sipaddr
, &netif
->autoip
->llipaddr
) &&
423 !eth_addr_cmp(&netifaddr
, &hdr
->shwaddr
)) {
424 LWIP_DEBUGF(AUTOIP_DEBUG
| LWIP_DBG_TRACE
| LWIP_DBG_STATE
| 1,
425 ("autoip_arp_reply(): Conflicting ARP-Packet detected\n"));
426 autoip_handle_arp_conflict(netif
);
432 #endif /* LWIP_AUTOIP */