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git.ipfire.org Git - people/ms/u-boot.git/blob - net/link_local.c
2 * RFC3927 ZeroConf IPv4 Link-Local addressing
3 * (see <http://www.zeroconf.org/>)
5 * Copied from BusyBox - networking/zcip.c
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
11 * Licensed under the GPL v2 or later
19 /* We don't need more than 32 bits of the counter */
20 #define MONOTONIC_MS() ((unsigned)get_timer(0) * (1000 / CONFIG_SYS_HZ))
24 LINKLOCAL_ADDR
= 0xa9fe0000,
26 IN_CLASSB_NET
= 0xffff0000,
27 IN_CLASSB_HOST
= 0x0000ffff,
29 /* protocol timeout parameters, specified in seconds */
35 RATE_LIMIT_INTERVAL
= 60,
38 ANNOUNCE_INTERVAL
= 2,
42 /* States during the configuration process. */
43 static enum ll_state_t
{
52 static struct in_addr ip
;
53 static int timeout_ms
= -1;
54 static unsigned deadline_ms
;
55 static unsigned conflicts
;
56 static unsigned nprobes
;
57 static unsigned nclaims
;
59 static unsigned int seed
;
61 static void link_local_timeout(void);
64 * Pick a random link local IP address on 169.254/16, except that
65 * the first and last 256 addresses are reserved.
67 static struct in_addr
pick(void)
73 tmp
= rand_r(&seed
) & IN_CLASSB_HOST
;
74 } while (tmp
> (IN_CLASSB_HOST
- 0x0200));
75 ip
.s_addr
= htonl((LINKLOCAL_ADDR
+ 0x0100) + tmp
);
80 * Return milliseconds of random delay, up to "secs" seconds.
82 static inline unsigned random_delay_ms(unsigned secs
)
84 return rand_r(&seed
) % (secs
* 1000);
87 static void configure_wait(void)
92 /* poll, being ready to adjust current timeout */
94 timeout_ms
= random_delay_ms(PROBE_WAIT
);
96 /* set deadline_ms to the point in time when we timeout */
97 deadline_ms
= MONOTONIC_MS() + timeout_ms
;
99 debug_cond(DEBUG_DEV_PKT
, "...wait %d %s nprobes=%u, nclaims=%u\n",
100 timeout_ms
, eth_get_name(), nprobes
, nclaims
);
102 net_set_timeout_handler(timeout_ms
, link_local_timeout
);
105 void link_local_start(void)
107 ip
= getenv_ip("llipaddr");
108 if (ip
.s_addr
!= 0 &&
109 (ntohl(ip
.s_addr
) & IN_CLASSB_NET
) != LINKLOCAL_ADDR
) {
110 puts("invalid link address");
111 net_set_state(NETLOOP_FAIL
);
114 net_netmask
.s_addr
= IN_CLASSB_NET
;
130 static void link_local_timeout(void)
134 /* timeouts in the PROBE state mean no conflicting ARP packets
135 have been received, so we can progress through the states */
136 if (nprobes
< PROBE_NUM
) {
137 struct in_addr zero_ip
= {.s_addr
= 0};
140 debug_cond(DEBUG_LL_STATE
, "probe/%u %s@%pI4\n",
141 nprobes
, eth_get_name(), &ip
);
142 arp_raw_request(zero_ip
, net_null_ethaddr
, ip
);
143 timeout_ms
= PROBE_MIN
* 1000;
144 timeout_ms
+= random_delay_ms(PROBE_MAX
- PROBE_MIN
);
146 /* Switch to announce state */
149 debug_cond(DEBUG_LL_STATE
, "announce/%u %s@%pI4\n",
150 nclaims
, eth_get_name(), &ip
);
151 arp_raw_request(ip
, net_ethaddr
, ip
);
152 timeout_ms
= ANNOUNCE_INTERVAL
* 1000;
155 case RATE_LIMIT_PROBE
:
156 /* timeouts in the RATE_LIMIT_PROBE state mean no conflicting
157 ARP packets have been received, so we can move immediately
158 to the announce state */
161 debug_cond(DEBUG_LL_STATE
, "announce/%u %s@%pI4\n",
162 nclaims
, eth_get_name(), &ip
);
163 arp_raw_request(ip
, net_ethaddr
, ip
);
164 timeout_ms
= ANNOUNCE_INTERVAL
* 1000;
167 /* timeouts in the ANNOUNCE state mean no conflicting ARP
168 packets have been received, so we can progress through
170 if (nclaims
< ANNOUNCE_NUM
) {
172 debug_cond(DEBUG_LL_STATE
, "announce/%u %s@%pI4\n",
173 nclaims
, eth_get_name(), &ip
);
174 arp_raw_request(ip
, net_ethaddr
, ip
);
175 timeout_ms
= ANNOUNCE_INTERVAL
* 1000;
177 /* Switch to monitor state */
179 printf("Successfully assigned %pI4\n", &ip
);
180 net_copy_ip(&net_ip
, &ip
);
184 /* Never timeout in the monitor state */
185 net_set_timeout_handler(0, NULL
);
187 /* NOTE: all other exit paths should deconfig ... */
188 net_set_state(NETLOOP_SUCCESS
);
193 /* We won! No ARP replies, so just go back to monitor */
199 /* Invalid, should never happen. Restart the whole protocol */
210 void link_local_receive_arp(struct arp_hdr
*arp
, int len
)
212 int source_ip_conflict
;
213 int target_ip_conflict
;
214 struct in_addr null_ip
= {.s_addr
= 0};
216 if (state
== DISABLED
)
219 /* We need to adjust the timeout in case we didn't receive a
220 conflicting packet. */
221 if (timeout_ms
> 0) {
222 unsigned diff
= deadline_ms
- MONOTONIC_MS();
223 if ((int)(diff
) < 0) {
224 /* Current time is greater than the expected timeout
225 time. This should never happen */
226 debug_cond(DEBUG_LL_STATE
,
227 "missed an expected timeout\n");
230 debug_cond(DEBUG_INT_STATE
, "adjusting timeout\n");
231 timeout_ms
= diff
| 1; /* never 0 */
235 /* XXX Don't bother with ethernet link just yet */
236 if ((fds
[0].revents
& POLLIN
) == 0) {
237 if (fds
[0].revents
& POLLERR
) {
239 * FIXME: links routinely go down;
241 bb_error_msg("iface %s is down", eth_get_name());
243 run(argv
, "deconfig", &ip
);
250 debug_cond(DEBUG_INT_STATE
, "%s recv arp type=%d, op=%d,\n",
251 eth_get_name(), ntohs(arp
->ar_pro
),
253 debug_cond(DEBUG_INT_STATE
, "\tsource=%pM %pI4\n",
256 debug_cond(DEBUG_INT_STATE
, "\ttarget=%pM %pI4\n",
260 if (arp
->ar_op
!= htons(ARPOP_REQUEST
) &&
261 arp
->ar_op
!= htons(ARPOP_REPLY
)) {
266 source_ip_conflict
= 0;
267 target_ip_conflict
= 0;
269 if (memcmp(&arp
->ar_spa
, &ip
, ARP_PLEN
) == 0 &&
270 memcmp(&arp
->ar_sha
, net_ethaddr
, ARP_HLEN
) != 0)
271 source_ip_conflict
= 1;
274 * According to RFC 3927, section 2.2.1:
275 * Check if packet is an ARP probe by checking for a null source IP
276 * then check that target IP is equal to ours and source hw addr
277 * is not equal to ours. This condition should cause a conflict only
280 if (arp
->ar_op
== htons(ARPOP_REQUEST
) &&
281 memcmp(&arp
->ar_spa
, &null_ip
, ARP_PLEN
) == 0 &&
282 memcmp(&arp
->ar_tpa
, &ip
, ARP_PLEN
) == 0 &&
283 memcmp(&arp
->ar_sha
, net_ethaddr
, ARP_HLEN
) != 0) {
284 target_ip_conflict
= 1;
287 debug_cond(DEBUG_NET_PKT
,
288 "state = %d, source ip conflict = %d, target ip conflict = "
289 "%d\n", state
, source_ip_conflict
, target_ip_conflict
);
293 /* When probing or announcing, check for source IP conflicts
294 and other hosts doing ARP probes (target IP conflicts). */
295 if (source_ip_conflict
|| target_ip_conflict
) {
298 if (conflicts
>= MAX_CONFLICTS
) {
299 debug("%s ratelimit\n", eth_get_name());
300 timeout_ms
= RATE_LIMIT_INTERVAL
* 1000;
301 state
= RATE_LIMIT_PROBE
;
304 /* restart the whole protocol */
312 /* If a conflict, we try to defend with a single ARP probe */
313 if (source_ip_conflict
) {
314 debug("monitor conflict -- defending\n");
316 timeout_ms
= DEFEND_INTERVAL
* 1000;
317 arp_raw_request(ip
, net_ethaddr
, ip
);
321 /* Well, we tried. Start over (on conflict) */
322 if (source_ip_conflict
) {
324 debug("defend conflict -- starting over\n");
328 /* restart the whole protocol */
336 /* Invalid, should never happen. Restart the whole protocol */
337 debug("invalid state -- starting over\n");