2 This file is part of systemd.
4 Copyright (C) 2013 Intel Corporation. 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 <net/ethernet.h>
25 #include <sys/param.h>
30 #include "dhcp-protocol.h"
31 #include "dhcp-lease.h"
32 #include "dhcp-internal.h"
33 #include "sd-dhcp-client.h"
35 struct sd_dhcp_client {
39 sd_event_source *timeout_resend;
42 union sockaddr_union link;
43 sd_event_source *receive_message;
45 size_t req_opts_allocated;
48 struct ether_addr mac_addr;
54 sd_event_source *timeout_t1;
55 sd_event_source *timeout_t2;
56 sd_event_source *timeout_expire;
57 sd_dhcp_client_cb_t cb;
62 static const uint8_t default_req_opts[] = {
63 DHCP_OPTION_SUBNET_MASK,
65 DHCP_OPTION_HOST_NAME,
66 DHCP_OPTION_DOMAIN_NAME,
67 DHCP_OPTION_DOMAIN_NAME_SERVER,
68 DHCP_OPTION_NTP_SERVER,
71 static int client_receive_message_raw(sd_event_source *s, int fd,
72 uint32_t revents, void *userdata);
73 static int client_receive_message_udp(sd_event_source *s, int fd,
74 uint32_t revents, void *userdata);
76 int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
78 assert_return(client, -EINVAL);
81 client->userdata = userdata;
86 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) {
89 assert_return(client, -EINVAL);
90 assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
94 case DHCP_OPTION_OVERLOAD:
95 case DHCP_OPTION_MESSAGE_TYPE:
96 case DHCP_OPTION_PARAMETER_REQUEST_LIST:
104 for (i = 0; i < client->req_opts_size; i++)
105 if (client->req_opts[i] == option)
108 if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated,
109 client->req_opts_size + 1))
112 client->req_opts[client->req_opts_size++] = option;
117 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
118 const struct in_addr *last_addr) {
119 assert_return(client, -EINVAL);
120 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
123 client->last_addr = last_addr->s_addr;
125 client->last_addr = INADDR_ANY;
130 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) {
131 assert_return(client, -EINVAL);
132 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
133 assert_return(interface_index >= -1, -EINVAL);
135 client->index = interface_index;
140 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
141 const struct ether_addr *addr) {
142 assert_return(client, -EINVAL);
143 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
145 memcpy(&client->mac_addr, addr, ETH_ALEN);
150 int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) {
151 assert_return(client, -EINVAL);
152 assert_return(ret, -EINVAL);
154 if (client->state != DHCP_STATE_BOUND &&
155 client->state != DHCP_STATE_RENEWING &&
156 client->state != DHCP_STATE_REBINDING)
157 return -EADDRNOTAVAIL;
159 *ret = sd_dhcp_lease_ref(client->lease);
164 static int client_notify(sd_dhcp_client *client, int event) {
166 client->cb(client, event, client->userdata);
171 static int client_stop(sd_dhcp_client *client, int error) {
172 assert_return(client, -EINVAL);
174 client->receive_message =
175 sd_event_source_unref(client->receive_message);
181 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
183 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
184 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
185 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
189 client_notify(client, error);
191 client->start_time = 0;
193 client->state = DHCP_STATE_INIT;
196 client->lease = sd_dhcp_lease_unref(client->lease);
198 log_dhcp_client(client, "STOPPED");
203 static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
204 uint8_t type, uint16_t secs, uint8_t **opt,
208 r = dhcp_message_init(message, BOOTREQUEST, client->xid, type,
213 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
215 if (client->state == DHCP_STATE_RENEWING ||
216 client->state == DHCP_STATE_REBINDING)
217 message->ciaddr = client->lease->address;
219 /* Some DHCP servers will refuse to issue an DHCP lease if the Client
220 Identifier option is not set */
221 r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
222 ETH_ALEN, &client->mac_addr);
226 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
229 r = dhcp_option_append(opt, optlen,
230 DHCP_OPTION_PARAMETER_REQUEST_LIST,
231 client->req_opts_size,
236 /* Some DHCP servers will send bigger DHCP packets than the
237 defined default size unless the Maximum Messge Size option
238 is explicitely set */
239 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
240 DHCP_MIN_OPTIONS_SIZE);
241 r = dhcp_option_append(opt, optlen,
242 DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
251 static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
253 _cleanup_free_ DHCPPacket *discover;
257 optlen = DHCP_MIN_OPTIONS_SIZE;
258 len = sizeof(DHCPPacket) + optlen;
260 discover = malloc0(len);
265 err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
266 secs, &opt, &optlen);
270 if (client->last_addr != INADDR_ANY) {
271 err = dhcp_option_append(&opt, &optlen,
272 DHCP_OPTION_REQUESTED_IP_ADDRESS,
273 4, &client->last_addr);
278 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
282 dhcp_packet_append_ip_headers(discover, len);
284 err = dhcp_network_send_raw_socket(client->fd, &client->link,
287 log_dhcp_client(client, "DISCOVER");
292 static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
293 _cleanup_free_ DHCPPacket *request;
298 optlen = DHCP_MIN_OPTIONS_SIZE;
299 len = DHCP_MESSAGE_SIZE + optlen;
301 request = malloc0(len);
305 err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs,
310 if (client->state == DHCP_STATE_REQUESTING) {
311 err = dhcp_option_append(&opt, &optlen,
312 DHCP_OPTION_REQUESTED_IP_ADDRESS,
313 4, &client->lease->address);
317 err = dhcp_option_append(&opt, &optlen,
318 DHCP_OPTION_SERVER_IDENTIFIER,
319 4, &client->lease->server_address);
324 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
328 if (client->state == DHCP_STATE_RENEWING) {
329 err = dhcp_network_send_udp_socket(client->fd,
330 client->lease->server_address,
333 len - DHCP_IP_UDP_SIZE);
335 dhcp_packet_append_ip_headers(request, len);
337 err = dhcp_network_send_raw_socket(client->fd, &client->link,
341 log_dhcp_client(client, "REQUEST");
346 static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now)
348 client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
353 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
355 sd_dhcp_client *client = userdata;
356 usec_t next_timeout = 0;
362 assert(client->event);
364 switch (client->state) {
365 case DHCP_STATE_RENEWING:
367 time_left = (client->lease->t2 - client->lease->t1) / 2;
371 next_timeout = usec + time_left * USEC_PER_SEC;
375 case DHCP_STATE_REBINDING:
377 time_left = (client->lease->lifetime - client->lease->t2) / 2;
381 next_timeout = usec + time_left * USEC_PER_SEC;
384 case DHCP_STATE_INIT:
385 case DHCP_STATE_INIT_REBOOT:
386 case DHCP_STATE_REBOOTING:
387 case DHCP_STATE_SELECTING:
388 case DHCP_STATE_REQUESTING:
389 case DHCP_STATE_BOUND:
391 if (client->attempt < 64)
392 client->attempt *= 2;
394 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
399 next_timeout += (random_u32() & 0x1fffff);
401 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
403 r = sd_event_add_monotonic(client->event,
404 &client->timeout_resend,
407 client_timeout_resend, client);
411 r = sd_event_source_set_priority(client->timeout_resend,
412 client->event_priority);
416 switch (client->state) {
417 case DHCP_STATE_INIT:
419 client_update_secs(client, usec);
421 r = client_send_discover(client, client->secs);
423 client->state = DHCP_STATE_SELECTING;
426 if (client->attempt >= 64)
432 case DHCP_STATE_SELECTING:
433 client_update_secs(client, usec);
435 r = client_send_discover(client, client->secs);
436 if (r < 0 && client->attempt >= 64)
441 case DHCP_STATE_REQUESTING:
442 case DHCP_STATE_RENEWING:
443 case DHCP_STATE_REBINDING:
444 r = client_send_request(client, client->secs);
445 if (r < 0 && client->attempt >= 64)
448 client->request_sent = usec;
452 case DHCP_STATE_INIT_REBOOT:
453 case DHCP_STATE_REBOOTING:
454 case DHCP_STATE_BOUND:
462 client_stop(client, r);
464 /* Errors were dealt with when stopping the client, don't spill
465 errors into the event loop handler */
469 static int client_initialize_events(sd_dhcp_client *client,
470 sd_event_io_handler_t io_callback,
475 assert(client->event);
477 r = sd_event_add_io(client->event, &client->receive_message,
478 client->fd, EPOLLIN, io_callback,
483 r = sd_event_source_set_priority(client->receive_message,
484 client->event_priority);
488 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
490 r = sd_event_add_monotonic(client->event,
491 &client->timeout_resend,
493 client_timeout_resend, client);
497 r = sd_event_source_set_priority(client->timeout_resend,
498 client->event_priority);
502 client_stop(client, r);
508 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
510 sd_dhcp_client *client = userdata;
512 log_dhcp_client(client, "EXPIRED");
514 client_stop(client, DHCP_EVENT_EXPIRED);
519 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
520 sd_dhcp_client *client = userdata;
523 if (client->fd >= 0) {
524 client->receive_message =
525 sd_event_source_unref(client->receive_message);
530 client->state = DHCP_STATE_REBINDING;
533 r = dhcp_network_bind_raw_socket(client->index, &client->link);
535 client_stop(client, r);
541 log_dhcp_client(client, "TIMEOUT T2");
543 return client_initialize_events(client, client_receive_message_raw,
547 static int client_timeout_t1(sd_event_source *s, uint64_t usec,
549 sd_dhcp_client *client = userdata;
552 client->state = DHCP_STATE_RENEWING;
555 r = dhcp_network_bind_udp_socket(client->index,
556 client->lease->address,
559 client_stop(client, r);
565 log_dhcp_client(client, "TIMEOUT T1");
567 return client_initialize_events(client, client_receive_message_udp, usec);
570 static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
572 _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
575 r = dhcp_lease_new(&lease);
579 r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
583 lease->address = offer->yiaddr;
585 if (lease->address == INADDR_ANY ||
586 lease->server_address == INADDR_ANY ||
587 lease->subnet_mask == INADDR_ANY ||
588 lease->lifetime == 0)
591 client->lease = lease;
594 log_dhcp_client(client, "OFFER");
599 static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
601 _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
604 r = dhcp_lease_new(&lease);
608 r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
610 log_dhcp_client(client, "NAK");
611 return DHCP_EVENT_NO_LEASE;
617 lease->address = ack->yiaddr;
619 if (lease->address == INADDR_ANY ||
620 lease->server_address == INADDR_ANY ||
621 lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
624 r = DHCP_EVENT_IP_ACQUIRE;
626 if (client->lease->address != lease->address ||
627 client->lease->subnet_mask != lease->subnet_mask ||
628 client->lease->router != lease->router) {
629 r = DHCP_EVENT_IP_CHANGE;
632 client->lease = sd_dhcp_lease_unref(client->lease);
635 client->lease = lease;
638 log_dhcp_client(client, "ACK");
643 static uint64_t client_compute_timeout(uint64_t request_sent,
645 return request_sent + (lifetime - 3) * USEC_PER_SEC +
646 + (random_u32() & 0x1fffff);
649 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
650 uint64_t next_timeout;
654 assert(client->event);
656 if (client->lease->lifetime < 10)
659 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
660 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
661 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
663 if (!client->lease->t1)
664 client->lease->t1 = client->lease->lifetime / 2;
666 next_timeout = client_compute_timeout(client->request_sent,
668 if (next_timeout < usec)
671 r = sd_event_add_monotonic(client->event,
675 client_timeout_t1, client);
679 r = sd_event_source_set_priority(client->timeout_t1,
680 client->event_priority);
684 if (!client->lease->t2)
685 client->lease->t2 = client->lease->lifetime * 7 / 8;
687 if (client->lease->t2 < client->lease->t1)
690 if (client->lease->lifetime < client->lease->t2)
693 next_timeout = client_compute_timeout(client->request_sent,
695 if (next_timeout < usec)
698 r = sd_event_add_monotonic(client->event,
702 client_timeout_t2, client);
706 r = sd_event_source_set_priority(client->timeout_t2,
707 client->event_priority);
711 next_timeout = client_compute_timeout(client->request_sent,
712 client->lease->lifetime);
713 if (next_timeout < usec)
716 r = sd_event_add_monotonic(client->event,
717 &client->timeout_expire, next_timeout,
719 client_timeout_expire, client);
723 r = sd_event_source_set_priority(client->timeout_expire,
724 client->event_priority);
731 static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
732 int len, usec_t time_now) {
733 int r = 0, notify_event = 0;
736 assert(client->event);
739 if (len < DHCP_MESSAGE_SIZE) {
740 log_dhcp_client(client, "message too small (%d bytes): "
745 if (message->op != BOOTREPLY) {
746 log_dhcp_client(client, "not a BOOTREPLY message: ignoring");
750 if (be32toh(message->xid) != client->xid) {
751 log_dhcp_client(client, "received xid (%u) does not match "
752 "expected (%u): ignoring",
753 be32toh(message->xid), client->xid);
757 if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet,
759 log_dhcp_client(client, "received chaddr does not match "
760 "expected: ignoring");
764 switch (client->state) {
765 case DHCP_STATE_SELECTING:
767 r = client_handle_offer(client, message, len);
770 client->timeout_resend =
771 sd_event_source_unref(client->timeout_resend);
773 client->state = DHCP_STATE_REQUESTING;
776 r = sd_event_add_monotonic(client->event,
777 &client->timeout_resend,
779 client_timeout_resend,
784 r = sd_event_source_set_priority(client->timeout_resend,
785 client->event_priority);
792 case DHCP_STATE_REQUESTING:
793 case DHCP_STATE_RENEWING:
794 case DHCP_STATE_REBINDING:
796 r = client_handle_ack(client, message, len);
798 if (r == DHCP_EVENT_NO_LEASE)
802 client->timeout_resend =
803 sd_event_source_unref(client->timeout_resend);
805 if (client->state == DHCP_STATE_REQUESTING)
806 notify_event = DHCP_EVENT_IP_ACQUIRE;
807 else if (r != DHCP_EVENT_IP_ACQUIRE)
810 client->state = DHCP_STATE_BOUND;
813 client->last_addr = client->lease->address;
815 r = client_set_lease_timeouts(client, time_now);
820 client_notify(client, notify_event);
822 client->receive_message =
823 sd_event_source_unref(client->receive_message);
832 case DHCP_STATE_INIT:
833 case DHCP_STATE_INIT_REBOOT:
834 case DHCP_STATE_REBOOTING:
835 case DHCP_STATE_BOUND:
841 if (r < 0 || r == DHCP_EVENT_NO_LEASE)
842 return client_stop(client, r);
847 static int client_receive_message_udp(sd_event_source *s, int fd,
848 uint32_t revents, void *userdata) {
849 sd_dhcp_client *client = userdata;
850 uint8_t buf[sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE];
851 int buflen = sizeof(buf);
857 assert(client->event);
859 len = read(fd, &buf, buflen);
863 r = sd_event_get_now_monotonic(client->event, &time_now);
865 return client_stop(client, r);
867 return client_handle_message(client, (DHCPMessage *) buf, len,
871 static int client_receive_message_raw(sd_event_source *s, int fd,
872 uint32_t revents, void *userdata) {
873 sd_dhcp_client *client = userdata;
874 uint8_t buf[sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE];
875 int buflen = sizeof(buf);
882 assert(client->event);
884 len = read(fd, &buf, buflen);
888 packet = (DHCPPacket *) buf;
890 r = dhcp_packet_verify_headers(packet, len);
894 len -= DHCP_IP_UDP_SIZE;
896 r = sd_event_get_now_monotonic(client->event, &time_now);
898 return client_stop(client, r);
900 return client_handle_message(client, &packet->dhcp, len, time_now);
903 int sd_dhcp_client_start(sd_dhcp_client *client) {
906 assert_return(client, -EINVAL);
907 assert_return(client->event, -EINVAL);
908 assert_return(client->index > 0, -EINVAL);
909 assert_return(client->state == DHCP_STATE_INIT ||
910 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
912 client->xid = random_u32();
914 r = dhcp_network_bind_raw_socket(client->index, &client->link);
917 client_stop(client, r);
922 client->start_time = now(CLOCK_MONOTONIC);
925 log_dhcp_client(client, "STARTED");
927 return client_initialize_events(client, client_receive_message_raw,
931 int sd_dhcp_client_stop(sd_dhcp_client *client) {
932 return client_stop(client, DHCP_EVENT_STOP);
935 int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
939 assert_return(client, -EINVAL);
940 assert_return(!client->event, -EBUSY);
943 client->event = sd_event_ref(event);
945 r = sd_event_default(&client->event);
950 client->event_priority = priority;
955 int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
956 assert_return(client, -EINVAL);
958 client->event = sd_event_unref(client->event);
963 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
967 return client->event;
970 void sd_dhcp_client_free(sd_dhcp_client *client) {
974 sd_dhcp_client_stop(client);
975 sd_dhcp_client_detach_event(client);
977 free(client->req_opts);
981 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
982 #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
984 int sd_dhcp_client_new(sd_dhcp_client **ret) {
985 _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
987 assert_return(ret, -EINVAL);
989 client = new0(sd_dhcp_client, 1);
993 client->state = DHCP_STATE_INIT;
998 client->req_opts_size = ELEMENTSOF(default_req_opts);
1000 client->req_opts = memdup(default_req_opts, client->req_opts_size);
1001 if (!client->req_opts)