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 #define DHCP_CLIENT_MIN_OPTIONS_SIZE 312
37 struct sd_dhcp_client {
41 sd_event_source *timeout_resend;
44 union sockaddr_union link;
45 sd_event_source *receive_message;
47 size_t req_opts_allocated;
50 struct ether_addr mac_addr;
56 sd_event_source *timeout_t1;
57 sd_event_source *timeout_t2;
58 sd_event_source *timeout_expire;
59 sd_dhcp_client_cb_t cb;
64 static const uint8_t default_req_opts[] = {
65 DHCP_OPTION_SUBNET_MASK,
67 DHCP_OPTION_HOST_NAME,
68 DHCP_OPTION_DOMAIN_NAME,
69 DHCP_OPTION_DOMAIN_NAME_SERVER,
70 DHCP_OPTION_NTP_SERVER,
73 static int client_receive_message(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);
201 static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
202 uint8_t type, uint16_t secs, uint8_t **opt,
206 r = dhcp_message_init(message, BOOTREQUEST, client->xid, type,
211 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
213 if (client->state == DHCP_STATE_RENEWING ||
214 client->state == DHCP_STATE_REBINDING)
215 message->ciaddr = client->lease->address;
217 /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
218 Identifier option is not set */
219 r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
220 ETH_ALEN, &client->mac_addr);
224 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
227 r = dhcp_option_append(opt, optlen,
228 DHCP_OPTION_PARAMETER_REQUEST_LIST,
229 client->req_opts_size,
234 /* Some DHCP servers will send bigger DHCP packets than the
235 defined default size unless the Maximum Messge Size option
236 is explicitely set */
237 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
238 DHCP_CLIENT_MIN_OPTIONS_SIZE);
239 r = dhcp_option_append(opt, optlen,
240 DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
249 static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
251 _cleanup_free_ DHCPPacket *discover;
255 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
256 len = sizeof(DHCPPacket) + optlen;
258 discover = malloc0(len);
263 err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
264 secs, &opt, &optlen);
268 if (client->last_addr != INADDR_ANY) {
269 err = dhcp_option_append(&opt, &optlen,
270 DHCP_OPTION_REQUESTED_IP_ADDRESS,
271 4, &client->last_addr);
276 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
280 dhcp_packet_append_ip_headers(discover, BOOTREQUEST, len);
282 err = dhcp_network_send_raw_socket(client->fd, &client->link,
288 static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
289 _cleanup_free_ DHCPPacket *request;
294 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
295 len = DHCP_MESSAGE_SIZE + optlen;
297 request = malloc0(len);
301 err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs,
306 if (client->state == DHCP_STATE_REQUESTING) {
307 err = dhcp_option_append(&opt, &optlen,
308 DHCP_OPTION_REQUESTED_IP_ADDRESS,
309 4, &client->lease->address);
313 err = dhcp_option_append(&opt, &optlen,
314 DHCP_OPTION_SERVER_IDENTIFIER,
315 4, &client->lease->server_address);
320 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
324 if (client->state == DHCP_STATE_RENEWING) {
325 err = dhcp_network_send_udp_socket(client->fd,
326 client->lease->server_address,
328 len - DHCP_IP_UDP_SIZE);
330 dhcp_packet_append_ip_headers(request, BOOTREQUEST, len);
332 err = dhcp_network_send_raw_socket(client->fd, &client->link,
339 static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now)
341 client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
346 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
348 sd_dhcp_client *client = userdata;
349 usec_t next_timeout = 0;
355 assert(client->event);
357 switch (client->state) {
358 case DHCP_STATE_RENEWING:
360 time_left = (client->lease->t2 - client->lease->t1)/2;
364 next_timeout = usec + time_left * USEC_PER_SEC;
368 case DHCP_STATE_REBINDING:
370 time_left = (client->lease->lifetime - client->lease->t2)/2;
374 next_timeout = usec + time_left * USEC_PER_SEC;
377 case DHCP_STATE_INIT:
378 case DHCP_STATE_INIT_REBOOT:
379 case DHCP_STATE_REBOOTING:
380 case DHCP_STATE_SELECTING:
381 case DHCP_STATE_REQUESTING:
382 case DHCP_STATE_BOUND:
384 if (client->attempt < 64)
385 client->attempt *= 2;
387 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
392 next_timeout += (random_u32() & 0x1fffff);
394 r = sd_event_add_monotonic(client->event, next_timeout,
396 client_timeout_resend, client,
397 &client->timeout_resend);
401 r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
405 switch (client->state) {
406 case DHCP_STATE_INIT:
408 client_update_secs(client, usec);
410 r = client_send_discover(client, client->secs);
412 client->state = DHCP_STATE_SELECTING;
415 if (client->attempt >= 64)
421 case DHCP_STATE_SELECTING:
422 client_update_secs(client, usec);
424 r = client_send_discover(client, client->secs);
425 if (r < 0 && client->attempt >= 64)
430 case DHCP_STATE_REQUESTING:
431 case DHCP_STATE_RENEWING:
432 case DHCP_STATE_REBINDING:
433 r = client_send_request(client, client->secs);
434 if (r < 0 && client->attempt >= 64)
437 client->request_sent = usec;
441 case DHCP_STATE_INIT_REBOOT:
442 case DHCP_STATE_REBOOTING:
443 case DHCP_STATE_BOUND:
451 client_stop(client, r);
453 /* Errors were dealt with when stopping the client, don't spill
454 errors into the event loop handler */
458 static int client_initialize_events(sd_dhcp_client *client, usec_t usec) {
462 assert(client->event);
464 r = sd_event_add_io(client->event, client->fd, EPOLLIN,
465 client_receive_message, client,
466 &client->receive_message);
470 r = sd_event_source_set_priority(client->receive_message, client->event_priority);
474 r = sd_event_add_monotonic(client->event, usec, 0,
475 client_timeout_resend, client,
476 &client->timeout_resend);
480 r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
484 client_stop(client, r);
490 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
492 sd_dhcp_client *client = userdata;
494 client_stop(client, DHCP_EVENT_EXPIRED);
499 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
500 sd_dhcp_client *client = userdata;
503 if (client->fd >= 0) {
504 client->receive_message =
505 sd_event_source_unref(client->receive_message);
510 client->state = DHCP_STATE_REBINDING;
513 r = dhcp_network_bind_raw_socket(client->index, &client->link);
515 client_stop(client, r);
521 return client_initialize_events(client, usec);
524 static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata) {
525 sd_dhcp_client *client = userdata;
528 client->state = DHCP_STATE_RENEWING;
531 r = dhcp_network_bind_udp_socket(client->index,
532 client->lease->address);
534 client_stop(client, r);
540 return client_initialize_events(client, usec);
543 static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
547 r = dhcp_packet_verify_headers(message, BOOTREPLY, len);
551 if (be32toh(message->dhcp.xid) != client->xid)
554 if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
561 static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
563 _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
566 r = client_verify_headers(client, offer, len);
570 r = dhcp_lease_new(&lease);
574 len = len - DHCP_IP_UDP_SIZE;
575 r = dhcp_option_parse(&offer->dhcp, len, dhcp_lease_parse_options,
580 lease->address = offer->dhcp.yiaddr;
582 if (lease->address == INADDR_ANY ||
583 lease->server_address == INADDR_ANY ||
584 lease->subnet_mask == INADDR_ANY ||
585 lease->lifetime == 0)
588 client->lease = lease;
594 static int client_receive_ack(sd_dhcp_client *client, const uint8_t *buf,
598 _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
601 if (client->state == DHCP_STATE_RENEWING) {
602 dhcp = (DHCPMessage *)buf;
604 ack = (DHCPPacket *)buf;
606 r = client_verify_headers(client, ack, len);
611 len -= DHCP_IP_UDP_SIZE;
614 r = dhcp_lease_new(&lease);
618 r = dhcp_option_parse(dhcp, len, dhcp_lease_parse_options, lease);
620 return DHCP_EVENT_NO_LEASE;
625 lease->address = dhcp->yiaddr;
627 if (lease->address == INADDR_ANY ||
628 lease->server_address == INADDR_ANY ||
629 lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
632 r = DHCP_EVENT_IP_ACQUIRE;
634 if (client->lease->address != lease->address ||
635 client->lease->subnet_mask != lease->subnet_mask ||
636 client->lease->router != lease->router) {
637 r = DHCP_EVENT_IP_CHANGE;
640 client->lease = sd_dhcp_lease_unref(client->lease);
643 client->lease = lease;
649 static uint64_t client_compute_timeout(uint64_t request_sent,
651 return request_sent + (lifetime - 3) * USEC_PER_SEC +
652 + (random_u32() & 0x1fffff);
655 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
656 uint64_t next_timeout;
660 assert(client->event);
662 if (client->lease->lifetime < 10)
665 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
666 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
667 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
669 if (!client->lease->t1)
670 client->lease->t1 = client->lease->lifetime / 2;
672 next_timeout = client_compute_timeout(client->request_sent,
674 if (next_timeout < usec)
677 r = sd_event_add_monotonic(client->event, next_timeout,
679 client_timeout_t1, client,
680 &client->timeout_t1);
684 r = sd_event_source_set_priority(client->timeout_t1, client->event_priority);
688 if (!client->lease->t2)
689 client->lease->t2 = client->lease->lifetime * 7 / 8;
691 if (client->lease->t2 < client->lease->t1)
694 if (client->lease->lifetime < client->lease->t2)
697 next_timeout = client_compute_timeout(client->request_sent,
699 if (next_timeout < usec)
702 r = sd_event_add_monotonic(client->event, next_timeout,
704 client_timeout_t2, client,
705 &client->timeout_t2);
709 r = sd_event_source_set_priority(client->timeout_t2, client->event_priority);
713 next_timeout = client_compute_timeout(client->request_sent,
714 client->lease->lifetime);
715 if (next_timeout < usec)
718 r = sd_event_add_monotonic(client->event, next_timeout,
720 client_timeout_expire, client,
721 &client->timeout_expire);
725 r = sd_event_source_set_priority(client->timeout_expire, client->event_priority);
732 static int client_receive_message(sd_event_source *s, int fd,
733 uint32_t revents, void *userdata) {
734 sd_dhcp_client *client = userdata;
735 uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
736 int buflen = sizeof(buf);
737 int len, r = 0, notify_event = 0;
743 assert(client->event);
745 len = read(fd, &buf, buflen);
749 r = sd_event_get_now_monotonic(client->event, &time_now);
753 switch (client->state) {
754 case DHCP_STATE_SELECTING:
756 message = (DHCPPacket *)&buf;
758 if (client_receive_offer(client, message, len) >= 0) {
760 client->timeout_resend =
761 sd_event_source_unref(client->timeout_resend);
763 client->state = DHCP_STATE_REQUESTING;
766 r = sd_event_add_monotonic(client->event, time_now, 0,
767 client_timeout_resend,
769 &client->timeout_resend);
773 r = sd_event_source_set_priority(client->timeout_resend, client->event_priority);
780 case DHCP_STATE_REQUESTING:
781 case DHCP_STATE_RENEWING:
782 case DHCP_STATE_REBINDING:
784 r = client_receive_ack(client, buf, len);
786 if (r == DHCP_EVENT_NO_LEASE)
790 client->timeout_resend =
791 sd_event_source_unref(client->timeout_resend);
793 if (client->state == DHCP_STATE_REQUESTING)
794 notify_event = DHCP_EVENT_IP_ACQUIRE;
795 else if (r != DHCP_EVENT_IP_ACQUIRE)
798 client->state = DHCP_STATE_BOUND;
801 client->last_addr = client->lease->address;
803 r = client_set_lease_timeouts(client, time_now);
808 client_notify(client, notify_event);
810 client->receive_message =
811 sd_event_source_unref(client->receive_message);
820 case DHCP_STATE_INIT:
821 case DHCP_STATE_INIT_REBOOT:
822 case DHCP_STATE_REBOOTING:
823 case DHCP_STATE_BOUND:
829 if (r < 0 || r == DHCP_EVENT_NO_LEASE)
830 return client_stop(client, r);
835 int sd_dhcp_client_start(sd_dhcp_client *client) {
838 assert_return(client, -EINVAL);
839 assert_return(client->event, -EINVAL);
840 assert_return(client->index > 0, -EINVAL);
841 assert_return(client->state == DHCP_STATE_INIT ||
842 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
844 client->xid = random_u32();
846 r = dhcp_network_bind_raw_socket(client->index, &client->link);
849 client_stop(client, r);
854 client->start_time = now(CLOCK_MONOTONIC);
857 return client_initialize_events(client, client->start_time);
860 int sd_dhcp_client_stop(sd_dhcp_client *client) {
861 return client_stop(client, DHCP_EVENT_STOP);
864 int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event, int priority) {
867 assert_return(client, -EINVAL);
868 assert_return(!client->event, -EBUSY);
871 client->event = sd_event_ref(event);
873 r = sd_event_default(&client->event);
878 client->event_priority = priority;
883 int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
884 assert_return(client, -EINVAL);
886 client->event = sd_event_unref(client->event);
891 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
895 return client->event;
898 void sd_dhcp_client_free(sd_dhcp_client *client) {
902 sd_dhcp_client_stop(client);
903 sd_dhcp_client_detach_event(client);
905 free(client->req_opts);
909 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
910 #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
912 int sd_dhcp_client_new(sd_dhcp_client **ret) {
913 _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
915 assert_return(ret, -EINVAL);
917 client = new0(sd_dhcp_client, 1);
921 client->state = DHCP_STATE_INIT;
926 client->req_opts_size = ELEMENTSOF(default_req_opts);
928 client->req_opts = memdup(default_req_opts, client->req_opts_size);
929 if (!client->req_opts)