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"
31 #include "ipv4ll-internal.h"
32 #include "sd-ipv4ll.h"
34 /* Constants from the RFC */
39 #define ANNOUNCE_WAIT 2
40 #define ANNOUNCE_NUM 2
41 #define ANNOUNCE_INTERVAL 2
42 #define MAX_CONFLICTS 10
43 #define RATE_LIMIT_INTERVAL 60
44 #define DEFEND_INTERVAL 10
46 #define IPV4LL_NETWORK 0xA9FE0000L
47 #define IPV4LL_NETMASK 0xFFFF0000L
49 typedef enum IPv4LLTrigger{
51 IPV4LL_TRIGGER_PACKET,
52 IPV4LL_TRIGGER_TIMEOUT,
54 _IPV4LL_TRIGGER_INVALID = -1
57 typedef enum IPv4LLState {
59 IPV4LL_STATE_WAITING_PROBE,
61 IPV4LL_STATE_WAITING_ANNOUNCE,
62 IPV4LL_STATE_ANNOUNCING,
65 _IPV4LL_STATE_INVALID = -1
74 union sockaddr_union link;
77 sd_event_source *receive_message;
78 sd_event_source *timer;
81 int next_wakeup_valid;
83 struct random_data *random_data;
84 char *random_data_state;
86 be32_t claimed_address;
87 struct ether_addr mac_addr;
94 static void ipv4ll_run_state_machine(sd_ipv4ll *ll, IPv4LLTrigger trigger, void *trigger_data);
96 static void ipv4ll_set_state(sd_ipv4ll *ll, IPv4LLState st, int reset_counter) {
99 assert(st < _IPV4LL_STATE_MAX);
101 if (st == ll->state && !reset_counter) {
109 static sd_ipv4ll *ipv4ll_client_notify(sd_ipv4ll *ll, int event) {
113 ll = sd_ipv4ll_ref(ll);
114 ll->cb(ll, event, ll->userdata);
115 ll = sd_ipv4ll_unref(ll);
121 static sd_ipv4ll *ipv4ll_stop(sd_ipv4ll *ll, int event) {
124 ll->receive_message = sd_event_source_unref(ll->receive_message);
125 ll->fd = safe_close(ll->fd);
127 ll->timer = sd_event_source_unref(ll->timer);
129 log_ipv4ll(ll, "STOPPED");
131 ll = ipv4ll_client_notify(ll, event);
134 ll->claimed_address = 0;
135 ipv4ll_set_state (ll, IPV4LL_STATE_INIT, 1);
141 static int ipv4ll_pick_address(sd_ipv4ll *ll, be32_t *address) {
148 assert(ll->random_data);
151 r = random_r(ll->random_data, &random);
154 addr = htonl((random & 0x0000FFFF) | IPV4LL_NETWORK);
155 } while (addr == ll->address ||
156 (ntohl(addr) & IPV4LL_NETMASK) != IPV4LL_NETWORK ||
157 (ntohl(addr) & 0x0000FF00) == 0x0000 ||
158 (ntohl(addr) & 0x0000FF00) == 0xFF00);
164 static int ipv4ll_timer(sd_event_source *s, uint64_t usec, void *userdata) {
165 sd_ipv4ll *ll = (sd_ipv4ll*)userdata;
169 ll->next_wakeup_valid = 0;
170 ipv4ll_run_state_machine(ll, IPV4LL_TRIGGER_TIMEOUT, NULL);
175 static void ipv4ll_set_next_wakeup(sd_ipv4ll *ll, int sec, int random_sec) {
176 usec_t next_timeout = 0;
180 assert(random_sec >= 0);
183 next_timeout = sec * USEC_PER_SEC;
186 next_timeout += random_u32() % (random_sec * USEC_PER_SEC);
188 if (sd_event_now(ll->event, CLOCK_MONOTONIC, &time_now) < 0)
189 time_now = now(CLOCK_MONOTONIC);
191 ll->next_wakeup = time_now + next_timeout;
192 ll->next_wakeup_valid = 1;
195 static bool ipv4ll_arp_conflict (sd_ipv4ll *ll, struct ether_arp *arp) {
199 if (memcmp(arp->arp_spa, &ll->address, sizeof(ll->address)) == 0 &&
200 memcmp(arp->arp_sha, &ll->mac_addr, ETH_ALEN) != 0)
206 static bool ipv4ll_arp_probe_conflict (sd_ipv4ll *ll, struct ether_arp *arp) {
210 if (ipv4ll_arp_conflict(ll, arp))
213 if (memcmp(arp->arp_tpa, &ll->address, sizeof(ll->address)) == 0 &&
214 memcmp(arp->arp_sha, &ll->mac_addr, ETH_ALEN))
220 static void ipv4ll_run_state_machine(sd_ipv4ll *ll, IPv4LLTrigger trigger, void *trigger_data) {
221 struct ether_arp out_packet;
222 int out_packet_ready = 0;
226 assert(trigger < _IPV4LL_TRIGGER_MAX);
228 if (ll->state == IPV4LL_STATE_INIT) {
230 log_ipv4ll(ll, "PROBE");
231 ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_PROBE, 1);
232 ipv4ll_set_next_wakeup(ll, 0, PROBE_WAIT);
234 } else if ((ll->state == IPV4LL_STATE_WAITING_PROBE && trigger == IPV4LL_TRIGGER_TIMEOUT) ||
235 (ll->state == IPV4LL_STATE_PROBING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration < PROBE_NUM-2)) {
238 arp_packet_probe(&out_packet, ll->address, &ll->mac_addr);
239 out_packet_ready = 1;
240 ipv4ll_set_state(ll, IPV4LL_STATE_PROBING, 0);
242 ipv4ll_set_next_wakeup(ll, PROBE_MIN, (PROBE_MAX-PROBE_MIN));
244 } else if (ll->state == IPV4LL_STATE_PROBING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration >= PROBE_NUM-2) {
246 /* Send the last probe */
247 arp_packet_probe(&out_packet, ll->address, &ll->mac_addr);
248 out_packet_ready = 1;
249 ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_ANNOUNCE, 1);
251 ipv4ll_set_next_wakeup(ll, ANNOUNCE_WAIT, 0);
253 } else if ((ll->state == IPV4LL_STATE_WAITING_ANNOUNCE && trigger == IPV4LL_TRIGGER_TIMEOUT) ||
254 (ll->state == IPV4LL_STATE_ANNOUNCING && trigger == IPV4LL_TRIGGER_TIMEOUT && ll->iteration < ANNOUNCE_NUM-1)) {
256 /* Send announcement packet */
257 arp_packet_announcement(&out_packet, ll->address, &ll->mac_addr);
258 out_packet_ready = 1;
259 ipv4ll_set_state(ll, IPV4LL_STATE_ANNOUNCING, 0);
261 ipv4ll_set_next_wakeup(ll, ANNOUNCE_INTERVAL, 0);
263 if (ll->iteration == 0) {
264 log_ipv4ll(ll, "ANNOUNCE");
265 ll->claimed_address = ll->address;
266 ll = ipv4ll_client_notify(ll, IPV4LL_EVENT_BIND);
273 } else if ((ll->state == IPV4LL_STATE_ANNOUNCING && trigger == IPV4LL_TRIGGER_TIMEOUT &&
274 ll->iteration >= ANNOUNCE_NUM-1)) {
276 ipv4ll_set_state(ll, IPV4LL_STATE_RUNNING, 0);
277 ll->next_wakeup_valid = 0;
279 } else if (trigger == IPV4LL_TRIGGER_PACKET) {
283 struct ether_arp* in_packet = (struct ether_arp*)trigger_data;
287 if (IN_SET(ll->state, IPV4LL_STATE_ANNOUNCING, IPV4LL_STATE_RUNNING)) {
289 if (ipv4ll_arp_conflict(ll, in_packet)) {
291 r = sd_event_now(ll->event, CLOCK_MONOTONIC, &time_now);
296 if (time_now > ll->defend_window) {
297 ll->defend_window = time_now + DEFEND_INTERVAL * USEC_PER_SEC;
298 arp_packet_announcement(&out_packet, ll->address, &ll->mac_addr);
299 out_packet_ready = 1;
304 } else if (IN_SET(ll->state, IPV4LL_STATE_WAITING_PROBE,
305 IPV4LL_STATE_PROBING,
306 IPV4LL_STATE_WAITING_ANNOUNCE)) {
308 conflicted = ipv4ll_arp_probe_conflict(ll, in_packet);
312 log_ipv4ll(ll, "CONFLICT");
313 ll = ipv4ll_client_notify(ll, IPV4LL_EVENT_CONFLICT);
317 ll->claimed_address = 0;
319 /* Pick a new address */
320 r = ipv4ll_pick_address(ll, &ll->address);
324 ll->defend_window = 0;
325 ipv4ll_set_state(ll, IPV4LL_STATE_WAITING_PROBE, 1);
327 if (ll->conflict >= MAX_CONFLICTS) {
328 log_ipv4ll(ll, "MAX_CONFLICTS");
329 ipv4ll_set_next_wakeup(ll, RATE_LIMIT_INTERVAL, PROBE_WAIT);
331 ipv4ll_set_next_wakeup(ll, 0, PROBE_WAIT);
336 if (out_packet_ready) {
337 r = arp_network_send_raw_socket(ll->fd, &ll->link, &out_packet);
339 log_ipv4ll(ll, "failed to send arp packet out");
344 if (ll->next_wakeup_valid) {
345 ll->timer = sd_event_source_unref(ll->timer);
346 r = sd_event_add_time(ll->event, &ll->timer, CLOCK_MONOTONIC,
347 ll->next_wakeup, 0, ipv4ll_timer, ll);
351 r = sd_event_source_set_priority(ll->timer, ll->event_priority);
361 static int ipv4ll_receive_message(sd_event_source *s, int fd,
362 uint32_t revents, void *userdata) {
364 struct ether_arp arp;
365 sd_ipv4ll *ll = (sd_ipv4ll*)userdata;
369 r = read(fd, &arp, sizeof(struct ether_arp));
370 if (r < (int) sizeof(struct ether_arp))
373 r = arp_packet_verify_headers(&arp);
377 ipv4ll_run_state_machine(ll, IPV4LL_TRIGGER_PACKET, &arp);
382 int sd_ipv4ll_set_index(sd_ipv4ll *ll, int interface_index) {
383 assert_return(ll, -EINVAL);
384 assert_return(interface_index >= -1, -EINVAL);
385 assert_return(ll->state == IPV4LL_STATE_INIT, -EBUSY);
387 ll->index = interface_index;
392 int sd_ipv4ll_set_mac(sd_ipv4ll *ll, const struct ether_addr *addr) {
393 bool need_restart = false;
395 assert_return(ll, -EINVAL);
396 assert_return(addr, -EINVAL);
398 if (memcmp(&ll->mac_addr, addr, ETH_ALEN) == 0)
401 if (ll->state != IPV4LL_STATE_INIT) {
402 log_ipv4ll(ll, "Changing MAC address on running IPv4LL "
403 "client, restarting");
404 ll = ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
411 memcpy(&ll->mac_addr, addr, ETH_ALEN);
419 int sd_ipv4ll_detach_event(sd_ipv4ll *ll) {
420 assert_return(ll, -EINVAL);
422 ll->event = sd_event_unref(ll->event);
427 int sd_ipv4ll_attach_event(sd_ipv4ll *ll, sd_event *event, int priority) {
430 assert_return(ll, -EINVAL);
431 assert_return(!ll->event, -EBUSY);
434 ll->event = sd_event_ref(event);
436 r = sd_event_default(&ll->event);
438 ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
443 ll->event_priority = priority;
448 int sd_ipv4ll_set_callback(sd_ipv4ll *ll, sd_ipv4ll_cb_t cb, void *userdata) {
449 assert_return(ll, -EINVAL);
452 ll->userdata = userdata;
457 int sd_ipv4ll_get_address(sd_ipv4ll *ll, struct in_addr *address){
458 assert_return(ll, -EINVAL);
459 assert_return(address, -EINVAL);
461 if (ll->claimed_address == 0) {
465 address->s_addr = ll->claimed_address;
469 int sd_ipv4ll_set_address_seed (sd_ipv4ll *ll, uint8_t seed[8]) {
470 unsigned int entropy = *seed;
473 assert_return(ll, -EINVAL);
475 free(ll->random_data);
476 free(ll->random_data_state);
478 ll->random_data = new0(struct random_data, 1);
479 ll->random_data_state = new0(char, 128);
481 if (!ll->random_data || !ll->random_data_state) {
486 r = initstate_r((unsigned int)entropy, ll->random_data_state, 128, ll->random_data);
492 free(ll->random_data);
493 free(ll->random_data_state);
494 ll->random_data = NULL;
495 ll->random_data_state = NULL;
500 bool sd_ipv4ll_is_running(sd_ipv4ll *ll) {
501 assert_return(ll, -EINVAL);
503 return ll->state != IPV4LL_STATE_INIT;
506 #define HASH_KEY SD_ID128_MAKE(df,04,22,98,3f,ad,14,52,f9,87,2e,d1,9c,70,e2,f2)
508 int sd_ipv4ll_start (sd_ipv4ll *ll) {
511 assert_return(ll, -EINVAL);
512 assert_return(ll->event, -EINVAL);
513 assert_return(ll->index > 0, -EINVAL);
514 assert_return(ll->state == IPV4LL_STATE_INIT, -EBUSY);
516 r = arp_network_bind_raw_socket(ll->index, &ll->link);
523 ll->defend_window = 0;
524 ll->claimed_address = 0;
526 if (!ll->random_data) {
529 /* Fallback to mac */
530 siphash24(seed, &ll->mac_addr.ether_addr_octet,
531 ETH_ALEN, HASH_KEY.bytes);
533 r = sd_ipv4ll_set_address_seed(ll, seed);
538 if (ll->address == 0) {
539 r = ipv4ll_pick_address(ll, &ll->address);
544 ipv4ll_set_state (ll, IPV4LL_STATE_INIT, 1);
546 r = sd_event_add_io(ll->event, &ll->receive_message, ll->fd,
547 EPOLLIN, ipv4ll_receive_message, ll);
551 r = sd_event_source_set_priority(ll->receive_message, ll->event_priority);
555 r = sd_event_add_time(ll->event,
558 now(CLOCK_MONOTONIC), 0,
564 r = sd_event_source_set_priority(ll->timer, ll->event_priority);
568 ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
573 int sd_ipv4ll_stop(sd_ipv4ll *ll) {
574 ipv4ll_stop(ll, IPV4LL_EVENT_STOP);
579 sd_ipv4ll *sd_ipv4ll_ref(sd_ipv4ll *ll) {
581 assert_se(REFCNT_INC(ll->n_ref) >= 2);
586 sd_ipv4ll *sd_ipv4ll_unref(sd_ipv4ll *ll) {
587 if (ll && REFCNT_DEC(ll->n_ref) <= 0) {
588 ll->receive_message =
589 sd_event_source_unref(ll->receive_message);
590 ll->fd = safe_close(ll->fd);
592 ll->timer = sd_event_source_unref(ll->timer);
594 sd_ipv4ll_detach_event(ll);
596 free(ll->random_data);
597 free(ll->random_data_state);
606 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_ipv4ll*, sd_ipv4ll_unref);
607 #define _cleanup_ipv4ll_free_ _cleanup_(sd_ipv4ll_unrefp)
609 int sd_ipv4ll_new(sd_ipv4ll **ret) {
610 _cleanup_ipv4ll_free_ sd_ipv4ll *ll = NULL;
612 assert_return(ret, -EINVAL);
614 ll = new0(sd_ipv4ll, 1);
618 ll->n_ref = REFCNT_INIT;
619 ll->state = IPV4LL_STATE_INIT;