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Joe Hershbergerd22c3382012-05-23 08:00:12 +00001/*
2 * RFC3927 ZeroConf IPv4 Link-Local addressing
3 * (see <http://www.zeroconf.org/>)
4 *
5 * Copied from BusyBox - networking/zcip.c
6 *
7 * Copyright (C) 2003 by Arthur van Hoff (avh@strangeberry.com)
8 * Copyright (C) 2004 by David Brownell
9 * Copyright (C) 2010 by Joe Hershberger
10 *
11 * Licensed under the GPL v2 or later
12 */
13
14#include <common.h>
15#include <net.h>
16#include "arp.h"
17#include "net_rand.h"
18
19/* We don't need more than 32 bits of the counter */
20#define MONOTONIC_MS() ((unsigned)get_timer(0) * (1000 / CONFIG_SYS_HZ))
21
22enum {
23/* 169.254.0.0 */
24 LINKLOCAL_ADDR = 0xa9fe0000,
25
26 IN_CLASSB_NET = 0xffff0000,
27 IN_CLASSB_HOST = 0x0000ffff,
28
29/* protocol timeout parameters, specified in seconds */
30 PROBE_WAIT = 1,
31 PROBE_MIN = 1,
32 PROBE_MAX = 2,
33 PROBE_NUM = 3,
34 MAX_CONFLICTS = 10,
35 RATE_LIMIT_INTERVAL = 60,
36 ANNOUNCE_WAIT = 2,
37 ANNOUNCE_NUM = 2,
38 ANNOUNCE_INTERVAL = 2,
39 DEFEND_INTERVAL = 10
40};
41
42/* States during the configuration process. */
43static enum ll_state_t {
44 PROBE = 0,
45 RATE_LIMIT_PROBE,
46 ANNOUNCE,
47 MONITOR,
48 DEFEND,
49 DISABLED
50} state = DISABLED;
51
52static IPaddr_t ip;
53static int timeout_ms = -1;
54static unsigned deadline_ms;
55static unsigned conflicts;
56static unsigned nprobes;
57static unsigned nclaims;
58static int ready;
Michael Walle99e139d2012-06-05 11:33:15 +000059static unsigned int seed;
Joe Hershbergerd22c3382012-05-23 08:00:12 +000060
61static void link_local_timeout(void);
62
63/**
64 * Pick a random link local IP address on 169.254/16, except that
65 * the first and last 256 addresses are reserved.
66 */
67static IPaddr_t pick(void)
68{
69 unsigned tmp;
70
71 do {
Michael Walle99e139d2012-06-05 11:33:15 +000072 tmp = rand_r(&seed) & IN_CLASSB_HOST;
Joe Hershbergerd22c3382012-05-23 08:00:12 +000073 } while (tmp > (IN_CLASSB_HOST - 0x0200));
74 return (IPaddr_t) htonl((LINKLOCAL_ADDR + 0x0100) + tmp);
75}
76
77/**
78 * Return milliseconds of random delay, up to "secs" seconds.
79 */
80static inline unsigned random_delay_ms(unsigned secs)
81{
Michael Walle99e139d2012-06-05 11:33:15 +000082 return rand_r(&seed) % (secs * 1000);
Joe Hershbergerd22c3382012-05-23 08:00:12 +000083}
84
85static void configure_wait(void)
86{
87 if (timeout_ms == -1)
88 return;
89
90 /* poll, being ready to adjust current timeout */
91 if (!timeout_ms)
92 timeout_ms = random_delay_ms(PROBE_WAIT);
93
94 /* set deadline_ms to the point in time when we timeout */
95 deadline_ms = MONOTONIC_MS() + timeout_ms;
96
Joe Hershberger4ef8d532012-05-23 08:01:04 +000097 debug_cond(DEBUG_DEV_PKT, "...wait %d %s nprobes=%u, nclaims=%u\n",
Joe Hershbergerd22c3382012-05-23 08:00:12 +000098 timeout_ms, eth_get_name(), nprobes, nclaims);
99
100 NetSetTimeout(timeout_ms, link_local_timeout);
101}
102
103void link_local_start(void)
104{
105 ip = getenv_IPaddr("llipaddr");
Joe Hershberger65b0db82012-11-05 06:13:45 +0000106 if (ip != 0 && (ntohl(ip) & IN_CLASSB_NET) != LINKLOCAL_ADDR) {
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000107 puts("invalid link address");
108 net_set_state(NETLOOP_FAIL);
109 return;
110 }
111 NetOurSubnetMask = IN_CLASSB_NET;
112
Michael Walle99e139d2012-06-05 11:33:15 +0000113 seed = seed_mac();
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000114 if (ip == 0)
115 ip = pick();
116
117 state = PROBE;
118 timeout_ms = 0;
119 conflicts = 0;
120 nprobes = 0;
121 nclaims = 0;
122 ready = 0;
123
124 configure_wait();
125}
126
127static void link_local_timeout(void)
128{
129 switch (state) {
130 case PROBE:
131 /* timeouts in the PROBE state mean no conflicting ARP packets
132 have been received, so we can progress through the states */
133 if (nprobes < PROBE_NUM) {
134 nprobes++;
Joe Hershberger4ef8d532012-05-23 08:01:04 +0000135 debug_cond(DEBUG_LL_STATE, "probe/%u %s@%pI4\n",
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000136 nprobes, eth_get_name(), &ip);
137 arp_raw_request(0, NetEtherNullAddr, ip);
138 timeout_ms = PROBE_MIN * 1000;
139 timeout_ms += random_delay_ms(PROBE_MAX - PROBE_MIN);
140 } else {
141 /* Switch to announce state */
142 state = ANNOUNCE;
143 nclaims = 0;
Joe Hershberger4ef8d532012-05-23 08:01:04 +0000144 debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000145 nclaims, eth_get_name(), &ip);
146 arp_raw_request(ip, NetOurEther, ip);
147 timeout_ms = ANNOUNCE_INTERVAL * 1000;
148 }
149 break;
150 case RATE_LIMIT_PROBE:
151 /* timeouts in the RATE_LIMIT_PROBE state mean no conflicting
152 ARP packets have been received, so we can move immediately
153 to the announce state */
154 state = ANNOUNCE;
155 nclaims = 0;
Joe Hershberger4ef8d532012-05-23 08:01:04 +0000156 debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000157 nclaims, eth_get_name(), &ip);
158 arp_raw_request(ip, NetOurEther, ip);
159 timeout_ms = ANNOUNCE_INTERVAL * 1000;
160 break;
161 case ANNOUNCE:
162 /* timeouts in the ANNOUNCE state mean no conflicting ARP
163 packets have been received, so we can progress through
164 the states */
165 if (nclaims < ANNOUNCE_NUM) {
166 nclaims++;
Joe Hershberger4ef8d532012-05-23 08:01:04 +0000167 debug_cond(DEBUG_LL_STATE, "announce/%u %s@%pI4\n",
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000168 nclaims, eth_get_name(), &ip);
169 arp_raw_request(ip, NetOurEther, ip);
170 timeout_ms = ANNOUNCE_INTERVAL * 1000;
171 } else {
172 /* Switch to monitor state */
173 state = MONITOR;
174 printf("Successfully assigned %pI4\n", &ip);
175 NetCopyIP(&NetOurIP, &ip);
176 ready = 1;
177 conflicts = 0;
178 timeout_ms = -1;
179 /* Never timeout in the monitor state */
180 NetSetTimeout(0, NULL);
181
182 /* NOTE: all other exit paths should deconfig ... */
183 net_set_state(NETLOOP_SUCCESS);
184 return;
185 }
186 break;
187 case DEFEND:
188 /* We won! No ARP replies, so just go back to monitor */
189 state = MONITOR;
190 timeout_ms = -1;
191 conflicts = 0;
192 break;
193 default:
194 /* Invalid, should never happen. Restart the whole protocol */
195 state = PROBE;
196 ip = pick();
197 timeout_ms = 0;
198 nprobes = 0;
199 nclaims = 0;
200 break;
201 }
202 configure_wait();
203}
204
205void link_local_receive_arp(struct arp_hdr *arp, int len)
206{
207 int source_ip_conflict;
208 int target_ip_conflict;
Joe Hershberger5da7cf82013-02-08 14:18:53 -0600209 IPaddr_t null_ip = 0;
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000210
211 if (state == DISABLED)
212 return;
213
214 /* We need to adjust the timeout in case we didn't receive a
215 conflicting packet. */
216 if (timeout_ms > 0) {
217 unsigned diff = deadline_ms - MONOTONIC_MS();
218 if ((int)(diff) < 0) {
219 /* Current time is greater than the expected timeout
220 time. This should never happen */
Joe Hershberger4ef8d532012-05-23 08:01:04 +0000221 debug_cond(DEBUG_LL_STATE,
222 "missed an expected timeout\n");
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000223 timeout_ms = 0;
224 } else {
Joe Hershberger4ef8d532012-05-23 08:01:04 +0000225 debug_cond(DEBUG_INT_STATE, "adjusting timeout\n");
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000226 timeout_ms = diff | 1; /* never 0 */
227 }
228 }
benoit.thebaudeau@advansb6841152012-07-19 01:19:34 +0000229#if 0
230 /* XXX Don't bother with ethernet link just yet */
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000231 if ((fds[0].revents & POLLIN) == 0) {
232 if (fds[0].revents & POLLERR) {
Wolfgang Denk3fe63832012-07-10 09:18:33 +0200233 /*
234 * FIXME: links routinely go down;
235 */
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000236 bb_error_msg("iface %s is down", eth_get_name());
237 if (ready) {
238 run(argv, "deconfig", &ip);
239 }
240 return EXIT_FAILURE;
241 }
242 continue;
243 }
benoit.thebaudeau@advansb6841152012-07-19 01:19:34 +0000244#endif
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000245
Joe Hershberger4ef8d532012-05-23 08:01:04 +0000246 debug_cond(DEBUG_INT_STATE, "%s recv arp type=%d, op=%d,\n",
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000247 eth_get_name(), ntohs(arp->ar_pro),
248 ntohs(arp->ar_op));
Joe Hershberger4ef8d532012-05-23 08:01:04 +0000249 debug_cond(DEBUG_INT_STATE, "\tsource=%pM %pI4\n",
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000250 &arp->ar_sha,
251 &arp->ar_spa);
Joe Hershberger4ef8d532012-05-23 08:01:04 +0000252 debug_cond(DEBUG_INT_STATE, "\ttarget=%pM %pI4\n",
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000253 &arp->ar_tha,
254 &arp->ar_tpa);
255
256 if (arp->ar_op != htons(ARPOP_REQUEST)
257 && arp->ar_op != htons(ARPOP_REPLY)
258 ) {
259 configure_wait();
260 return;
261 }
262
263 source_ip_conflict = 0;
264 target_ip_conflict = 0;
265
266 if (memcmp(&arp->ar_spa, &ip, ARP_PLEN) == 0
267 && memcmp(&arp->ar_sha, NetOurEther, ARP_HLEN) != 0
268 ) {
269 source_ip_conflict = 1;
270 }
Joe Hershberger5da7cf82013-02-08 14:18:53 -0600271
272 /*
273 * According to RFC 3927, section 2.2.1:
274 * Check if packet is an ARP probe by checking for a null source IP
275 * then check that target IP is equal to ours and source hw addr
276 * is not equal to ours. This condition should cause a conflict only
277 * during probe.
278 */
279 if (arp->ar_op == htons(ARPOP_REQUEST) &&
280 memcmp(&arp->ar_spa, &null_ip, ARP_PLEN) == 0 &&
281 memcmp(&arp->ar_tpa, &ip, ARP_PLEN) == 0 &&
282 memcmp(&arp->ar_sha, NetOurEther, ARP_HLEN) != 0) {
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000283 target_ip_conflict = 1;
284 }
285
Joe Hershberger4ef8d532012-05-23 08:01:04 +0000286 debug_cond(DEBUG_NET_PKT,
287 "state = %d, source ip conflict = %d, target ip conflict = "
288 "%d\n", state, source_ip_conflict, target_ip_conflict);
Joe Hershbergerd22c3382012-05-23 08:00:12 +0000289 switch (state) {
290 case PROBE:
291 case ANNOUNCE:
292 /* When probing or announcing, check for source IP conflicts
293 and other hosts doing ARP probes (target IP conflicts). */
294 if (source_ip_conflict || target_ip_conflict) {
295 conflicts++;
296 state = PROBE;
297 if (conflicts >= MAX_CONFLICTS) {
298 debug("%s ratelimit\n", eth_get_name());
299 timeout_ms = RATE_LIMIT_INTERVAL * 1000;
300 state = RATE_LIMIT_PROBE;
301 }
302
303 /* restart the whole protocol */
304 ip = pick();
305 timeout_ms = 0;
306 nprobes = 0;
307 nclaims = 0;
308 }
309 break;
310 case MONITOR:
311 /* If a conflict, we try to defend with a single ARP probe */
312 if (source_ip_conflict) {
313 debug("monitor conflict -- defending\n");
314 state = DEFEND;
315 timeout_ms = DEFEND_INTERVAL * 1000;
316 arp_raw_request(ip, NetOurEther, ip);
317 }
318 break;
319 case DEFEND:
320 /* Well, we tried. Start over (on conflict) */
321 if (source_ip_conflict) {
322 state = PROBE;
323 debug("defend conflict -- starting over\n");
324 ready = 0;
325 NetOurIP = 0;
326
327 /* restart the whole protocol */
328 ip = pick();
329 timeout_ms = 0;
330 nprobes = 0;
331 nclaims = 0;
332 }
333 break;
334 default:
335 /* Invalid, should never happen. Restart the whole protocol */
336 debug("invalid state -- starting over\n");
337 state = PROBE;
338 ip = pick();
339 timeout_ms = 0;
340 nprobes = 0;
341 nclaims = 0;
342 break;
343 }
344 configure_wait();
345}