2 This file is part of systemd.
4 Copyright (C) 2014 Axis Communications AB. All rights reserved.
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
24 #include <arpa/inet.h>
27 #include "siphash24.h"
30 #include "ipv4ll-internal.h"
31 #include "sd-ipv4ll.h"
33 /* Constants from the RFC */
38 #define ANNOUNCE_WAIT 2
39 #define ANNOUNCE_NUM 2
40 #define ANNOUNCE_INTERVAL 2
41 #define MAX_CONFLICTS 10
42 #define RATE_LIMIT_INTERVAL 60
43 #define DEFEND_INTERVAL 10
45 #define IPV4LL_NETWORK 0xA9FE0000L
46 #define IPV4LL_NETMASK 0xFFFF0000L
48 typedef enum IPv4LLTrigger{
50 IPV4LL_TRIGGER_PACKET,
51 IPV4LL_TRIGGER_TIMEOUT,
53 _IPV4LL_TRIGGER_INVALID = -1
56 typedef enum IPv4LLState {
58 IPV4LL_STATE_WAITING_PROBE,
60 IPV4LL_STATE_WAITING_ANNOUNCE,
61 IPV4LL_STATE_ANNOUNCING,
64 _IPV4LL_STATE_INVALID = -1
71 union sockaddr_union link;
74 sd_event_source *receive_message;
75 sd_event_source *timer;
78 int next_wakeup_valid;
80 struct random_data *random_data;
81 char *random_data_state;
83 be32_t claimed_address;
84 struct ether_addr mac_addr;
91 static void ipv4ll_run_state_machine(sd_ipv4ll *ll, IPv4LLTrigger trigger, void *trigger_data);
93 static void ipv4ll_set_state(sd_ipv4ll *ll, IPv4LLState st, int reset_counter) {
96 assert(st < _IPV4LL_STATE_MAX);
98 if (st == ll->state && !reset_counter) {
106 static int ipv4ll_client_notify(sd_ipv4ll *ll, int event) {
110 ll->cb(ll, event, ll->userdata);
115 static int ipv4ll_stop(sd_ipv4ll *ll, int event) {
118 ll->receive_message = sd_event_source_unref(ll->receive_message);
119 ll->fd = safe_close(ll->fd);
121 ll->timer = sd_event_source_unref(ll->timer);
123 ipv4ll_client_notify(ll, event);
125 ll->claimed_address = 0;
127 ipv4ll_set_state (ll, IPV4LL_STATE_INIT, 1);
129 log_ipv4ll(ll, "STOPPED");
134 static int ipv4ll_pick_address(sd_ipv4ll *ll, be32_t *address) {
141 assert(ll->random_data);
144 r = random_r(ll->random_data, &random);
147 addr = htonl((random & 0x0000FFFF) | IPV4LL_NETWORK);
148 } while (addr == ll->address ||
149 (ntohl(addr) & IPV4LL_NETMASK) != IPV4LL_NETWORK ||
150 (ntohl(addr) & 0x0000FF00) == 0x0000 ||
151 (ntohl(addr) & 0x0000FF00) == 0xFF00);
157 static int ipv4ll_timer(sd_event_source *s, uint64_t usec, void *userdata) {
158 sd_ipv4ll *ll = (sd_ipv4ll*)userdata;
162 ll->next_wakeup_valid = 0;
163 ipv4ll_run_state_machine(ll, IPV4LL_TRIGGER_TIMEOUT, NULL);
168 static void ipv4ll_set_next_wakeup (sd_ipv4ll *ll, int sec, int random_sec) {
169 usec_t next_timeout = 0;
173 assert(random_sec >= 0);
176 next_timeout = sec * USEC_PER_SEC;
179 next_timeout += random_u32() % (random_sec * USEC_PER_SEC);
181 if (sd_event_get_now_monotonic(ll->event, &time_now) < 0)
182 time_now = now(CLOCK_MONOTONIC);
184 ll->next_wakeup = time_now + next_timeout;
185 ll->next_wakeup_valid = 1;
188 static bool ipv4ll_arp_conflict (sd_ipv4ll *ll, struct ether_arp *arp) {
192 if (memcmp(arp->arp_spa, &ll->address, sizeof(ll->address)) == 0 &&
193 memcmp(arp->arp_sha, &ll->mac_addr, ETH_ALEN) != 0)
199 static bool ipv4ll_arp_probe_conflict (sd_ipv4ll *ll, struct ether_arp *arp) {
203 if (ipv4ll_arp_conflict(ll, arp))
206 if (memcmp(arp->arp_tpa, &ll->address, sizeof(ll->address)) == 0 &&
207 memcmp(arp->arp_sha, &ll->mac_addr, ETH_ALEN))
213 static void ipv4ll_run_state_machine(sd_ipv4ll *ll, IPv4LLTrigger trigger, void *trigger_data) {
214 struct ether_arp out_packet;
215 int out_packet_ready = 0;
219 assert(trigger < _IPV4LL_TRIGGER_MAX);
221 if (ll->state == IPV4LL_STATE_INIT) {
223 log_ipv4ll(ll, "PROBE");
224 ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_PROBE, 1);
225 ipv4ll_set_next_wakeup(ll, 0, PROBE_WAIT);
227 } else if ((ll->state == IPV4LL_STATE_WAITING_PROBE && trigger == IPV4LL_TRIGGER_TIMEOUT) ||
228 (ll->state == IPV4LL_STATE_PROBING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration < PROBE_NUM-2)) {
231 arp_packet_probe(&out_packet, ll->address, &ll->mac_addr);
232 out_packet_ready = 1;
233 ipv4ll_set_state(ll, IPV4LL_STATE_PROBING, 0);
235 ipv4ll_set_next_wakeup(ll, PROBE_MIN, (PROBE_MAX-PROBE_MIN));
237 } else if (ll->state == IPV4LL_STATE_PROBING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration >= PROBE_NUM-2) {
239 /* Send the last probe */
240 arp_packet_probe(&out_packet, ll->address, &ll->mac_addr);
241 out_packet_ready = 1;
242 ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_ANNOUNCE, 1);
244 ipv4ll_set_next_wakeup(ll, ANNOUNCE_WAIT, 0);
246 } else if ((ll->state == IPV4LL_STATE_WAITING_ANNOUNCE && trigger == IPV4LL_TRIGGER_TIMEOUT) ||
247 (ll->state == IPV4LL_STATE_ANNOUNCING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration < ANNOUNCE_NUM-1)) {
249 /* Send announcement packet */
250 arp_packet_announcement(&out_packet, ll->address, &ll->mac_addr);
251 out_packet_ready = 1;
252 ipv4ll_set_state(ll, IPV4LL_STATE_ANNOUNCING, 0);
254 ipv4ll_set_next_wakeup(ll, ANNOUNCE_INTERVAL, 0);
256 if (ll->iteration == 0) {
257 log_ipv4ll(ll, "ANNOUNCE");
258 ll->claimed_address = ll->address;
259 r = ipv4ll_client_notify(ll, IPV4LL_EVENT_BIND);
263 } else if ((ll->state == IPV4LL_STATE_ANNOUNCING && trigger == IPV4LL_TRIGGER_TIMEOUT &&
264 ll->iteration >= ANNOUNCE_NUM-1)) {
266 ipv4ll_set_state(ll, IPV4LL_STATE_RUNNING, 0);
267 ll->next_wakeup_valid = 0;
269 } else if (trigger == IPV4LL_TRIGGER_PACKET) {
273 struct ether_arp* in_packet = (struct ether_arp*)trigger_data;
277 if (IN_SET(ll->state, IPV4LL_STATE_ANNOUNCING, IPV4LL_STATE_RUNNING)) {
279 if (ipv4ll_arp_conflict(ll, in_packet)) {
281 r = sd_event_get_now_monotonic(ll->event, &time_now);
286 if (time_now > ll->defend_window) {
287 ll->defend_window = time_now + DEFEND_INTERVAL * USEC_PER_SEC;
288 arp_packet_announcement(&out_packet, ll->address, &ll->mac_addr);
289 out_packet_ready = 1;
294 } else if (IN_SET(ll->state, IPV4LL_STATE_WAITING_PROBE,
295 IPV4LL_STATE_PROBING,
296 IPV4LL_STATE_WAITING_ANNOUNCE)) {
298 conflicted = ipv4ll_arp_probe_conflict(ll, in_packet);
302 log_ipv4ll(ll, "CONFLICT");
303 r = ipv4ll_client_notify(ll, IPV4LL_EVENT_CONFLICT);
304 ll->claimed_address = 0;
306 /* Pick a new address */
307 r = ipv4ll_pick_address(ll, &ll->address);
311 ll->defend_window = 0;
312 ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_PROBE, 1);
314 if (ll->conflict >= MAX_CONFLICTS) {
315 log_ipv4ll(ll, "MAX_CONFLICTS");
316 ipv4ll_set_next_wakeup(ll, RATE_LIMIT_INTERVAL, PROBE_WAIT);
318 ipv4ll_set_next_wakeup(ll, 0, PROBE_WAIT);
323 if (out_packet_ready) {
324 r = arp_network_send_raw_socket(ll->fd, &ll->link, &out_packet);
326 log_ipv4ll(ll, "failed to send arp packet out");
331 if (ll->next_wakeup_valid) {
332 ll->timer = sd_event_source_unref(ll->timer);
333 r = sd_event_add_monotonic(ll->event, &ll->timer,
334 ll->next_wakeup, 0, ipv4ll_timer, ll);
338 r = sd_event_source_set_priority(ll->timer, ll->event_priority);
348 static int ipv4ll_receive_message(sd_event_source *s, int fd,
349 uint32_t revents, void *userdata) {
351 struct ether_arp arp;
352 sd_ipv4ll *ll = (sd_ipv4ll*)userdata;
356 r = read(fd, &arp, sizeof(struct ether_arp));
357 if (r < (int) sizeof(struct ether_arp))
360 r = arp_packet_verify_headers(&arp);
364 ipv4ll_run_state_machine(ll, IPV4LL_TRIGGER_PACKET, &arp);
369 int sd_ipv4ll_set_index(sd_ipv4ll *ll, int interface_index) {
370 assert_return(ll, -EINVAL);
371 assert_return(interface_index >= -1, -EINVAL);
372 assert_return(ll->state == IPV4LL_STATE_INIT, -EBUSY);
374 ll->index = interface_index;
379 int sd_ipv4ll_set_mac(sd_ipv4ll *ll, const struct ether_addr *addr) {
380 bool need_restart = false;
382 assert_return(ll, -EINVAL);
383 assert_return(addr, -EINVAL);
385 if (memcmp(&ll->mac_addr, addr, ETH_ALEN) == 0)
388 if (ll->state != IPV4LL_STATE_INIT) {
389 log_ipv4ll(ll, "Changing MAC address on running IPv4LL "
390 "client, restarting");
395 memcpy(&ll->mac_addr, addr, ETH_ALEN);
403 int sd_ipv4ll_detach_event(sd_ipv4ll *ll) {
404 assert_return(ll, -EINVAL);
406 ll->event = sd_event_unref(ll->event);
411 int sd_ipv4ll_attach_event(sd_ipv4ll *ll, sd_event *event, int priority) {
414 assert_return(ll, -EINVAL);
415 assert_return(!ll->event, -EBUSY);
418 ll->event = sd_event_ref(event);
420 r = sd_event_default(&ll->event);
422 ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
427 ll->event_priority = priority;
432 int sd_ipv4ll_set_callback(sd_ipv4ll *ll, sd_ipv4ll_cb_t cb, void *userdata) {
433 assert_return(ll, -EINVAL);
436 ll->userdata = userdata;
441 int sd_ipv4ll_get_address(sd_ipv4ll *ll, struct in_addr *address){
442 assert_return(ll, -EINVAL);
443 assert_return(address, -EINVAL);
445 if (ll->claimed_address == 0) {
449 address->s_addr = ll->claimed_address;
453 int sd_ipv4ll_set_address_seed (sd_ipv4ll *ll, uint8_t seed[8]) {
454 unsigned int entropy = *seed;
457 assert_return(ll, -EINVAL);
459 free(ll->random_data);
460 free(ll->random_data_state);
462 ll->random_data = new0(struct random_data, 1);
463 ll->random_data_state = new0(char, 128);
465 if (!ll->random_data || !ll->random_data_state) {
470 r = initstate_r((unsigned int)entropy, ll->random_data_state, 128, ll->random_data);
476 free(ll->random_data);
477 free(ll->random_data_state);
478 ll->random_data = NULL;
479 ll->random_data_state = NULL;
484 #define HASH_KEY SD_ID128_MAKE(df,04,22,98,3f,ad,14,52,f9,87,2e,d1,9c,70,e2,f2)
486 int sd_ipv4ll_start (sd_ipv4ll *ll) {
489 assert_return(ll, -EINVAL);
490 assert_return(ll->event, -EINVAL);
491 assert_return(ll->index > 0, -EINVAL);
492 assert_return(ll->state == IPV4LL_STATE_INIT, -EBUSY);
494 r = arp_network_bind_raw_socket(ll->index, &ll->link);
501 ll->defend_window = 0;
502 ll->claimed_address = 0;
504 if (!ll->random_data) {
507 /* Fallback to mac */
508 siphash24(seed, &ll->mac_addr.ether_addr_octet,
509 ETH_ALEN, HASH_KEY.bytes);
511 r = sd_ipv4ll_set_address_seed(ll, seed);
516 if (ll->address == 0) {
517 r = ipv4ll_pick_address(ll, &ll->address);
522 ipv4ll_set_state (ll, IPV4LL_STATE_INIT, 1);
524 r = sd_event_add_io(ll->event, &ll->receive_message, ll->fd,
525 EPOLLIN, ipv4ll_receive_message, ll);
529 r = sd_event_source_set_priority(ll->receive_message, ll->event_priority);
533 r = sd_event_add_monotonic(ll->event, &ll->timer, now(CLOCK_MONOTONIC), 0,
539 r = sd_event_source_set_priority(ll->timer, ll->event_priority);
543 ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
548 int sd_ipv4ll_stop(sd_ipv4ll *ll) {
549 return ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
552 void sd_ipv4ll_free (sd_ipv4ll *ll) {
557 sd_ipv4ll_detach_event(ll);
559 free(ll->random_data);
560 free(ll->random_data_state);
564 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_ipv4ll*, sd_ipv4ll_free);
565 #define _cleanup_ipv4ll_free_ _cleanup_(sd_ipv4ll_freep)
567 int sd_ipv4ll_new(sd_ipv4ll **ret) {
568 _cleanup_ipv4ll_free_ sd_ipv4ll *ll = NULL;
570 assert_return(ret, -EINVAL);
572 ll = new0(sd_ipv4ll, 1);
576 ll->state = IPV4LL_STATE_INIT;