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>
26 #include <sys/ioctl.h>
31 #include "dhcp-protocol.h"
32 #include "dhcp-lease.h"
33 #include "dhcp-internal.h"
34 #include "sd-dhcp-client.h"
36 struct sd_dhcp_client {
40 sd_event_source *timeout_resend;
43 union sockaddr_union link;
44 sd_event_source *receive_message;
46 size_t req_opts_allocated;
49 struct ether_addr mac_addr;
55 sd_event_source *timeout_t1;
56 sd_event_source *timeout_t2;
57 sd_event_source *timeout_expire;
58 sd_dhcp_client_cb_t cb;
63 static const uint8_t default_req_opts[] = {
64 DHCP_OPTION_SUBNET_MASK,
66 DHCP_OPTION_HOST_NAME,
67 DHCP_OPTION_DOMAIN_NAME,
68 DHCP_OPTION_DOMAIN_NAME_SERVER,
69 DHCP_OPTION_NTP_SERVER,
72 static int client_receive_message_raw(sd_event_source *s, int fd,
73 uint32_t revents, void *userdata);
74 static int client_receive_message_udp(sd_event_source *s, int fd,
75 uint32_t revents, void *userdata);
77 int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
79 assert_return(client, -EINVAL);
82 client->userdata = userdata;
87 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option) {
90 assert_return(client, -EINVAL);
91 assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
95 case DHCP_OPTION_OVERLOAD:
96 case DHCP_OPTION_MESSAGE_TYPE:
97 case DHCP_OPTION_PARAMETER_REQUEST_LIST:
105 for (i = 0; i < client->req_opts_size; i++)
106 if (client->req_opts[i] == option)
109 if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated,
110 client->req_opts_size + 1))
113 client->req_opts[client->req_opts_size++] = option;
118 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
119 const struct in_addr *last_addr) {
120 assert_return(client, -EINVAL);
121 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
124 client->last_addr = last_addr->s_addr;
126 client->last_addr = INADDR_ANY;
131 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index) {
132 assert_return(client, -EINVAL);
133 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
134 assert_return(interface_index >= -1, -EINVAL);
136 client->index = interface_index;
141 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
142 const struct ether_addr *addr) {
143 assert_return(client, -EINVAL);
144 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
146 memcpy(&client->mac_addr, addr, ETH_ALEN);
151 int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) {
152 assert_return(client, -EINVAL);
153 assert_return(ret, -EINVAL);
155 if (client->state != DHCP_STATE_BOUND &&
156 client->state != DHCP_STATE_RENEWING &&
157 client->state != DHCP_STATE_REBINDING)
158 return -EADDRNOTAVAIL;
160 *ret = sd_dhcp_lease_ref(client->lease);
165 static int client_notify(sd_dhcp_client *client, int event) {
167 client->cb(client, event, client->userdata);
172 static int client_stop(sd_dhcp_client *client, int error) {
173 assert_return(client, -EINVAL);
175 client->receive_message =
176 sd_event_source_unref(client->receive_message);
182 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
184 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
185 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
186 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
190 client_notify(client, error);
192 client->start_time = 0;
194 client->state = DHCP_STATE_INIT;
197 client->lease = sd_dhcp_lease_unref(client->lease);
199 log_dhcp_client(client, "STOPPED");
204 static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
205 uint8_t type, uint16_t secs, uint8_t **opt,
209 r = dhcp_message_init(message, BOOTREQUEST, client->xid, type,
214 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
216 if (client->state == DHCP_STATE_RENEWING ||
217 client->state == DHCP_STATE_REBINDING)
218 message->ciaddr = client->lease->address;
220 /* Some DHCP servers will refuse to issue an DHCP lease if the Client
221 Identifier option is not set */
222 r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
223 ETH_ALEN, &client->mac_addr);
227 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
230 r = dhcp_option_append(opt, optlen,
231 DHCP_OPTION_PARAMETER_REQUEST_LIST,
232 client->req_opts_size,
237 /* Some DHCP servers will send bigger DHCP packets than the
238 defined default size unless the Maximum Messge Size option
239 is explicitely set */
240 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
241 DHCP_MIN_OPTIONS_SIZE);
242 r = dhcp_option_append(opt, optlen,
243 DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
252 static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
254 _cleanup_free_ DHCPPacket *discover;
258 optlen = DHCP_MIN_OPTIONS_SIZE;
259 len = sizeof(DHCPPacket) + optlen;
261 discover = malloc0(len);
266 err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
267 secs, &opt, &optlen);
271 if (client->last_addr != INADDR_ANY) {
272 err = dhcp_option_append(&opt, &optlen,
273 DHCP_OPTION_REQUESTED_IP_ADDRESS,
274 4, &client->last_addr);
279 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
283 dhcp_packet_append_ip_headers(discover, len);
285 err = dhcp_network_send_raw_socket(client->fd, &client->link,
288 log_dhcp_client(client, "DISCOVER");
293 static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
294 _cleanup_free_ DHCPPacket *request;
299 optlen = DHCP_MIN_OPTIONS_SIZE;
300 len = DHCP_MESSAGE_SIZE + optlen;
302 request = malloc0(len);
306 err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs,
311 if (client->state == DHCP_STATE_REQUESTING) {
312 err = dhcp_option_append(&opt, &optlen,
313 DHCP_OPTION_REQUESTED_IP_ADDRESS,
314 4, &client->lease->address);
318 err = dhcp_option_append(&opt, &optlen,
319 DHCP_OPTION_SERVER_IDENTIFIER,
320 4, &client->lease->server_address);
325 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
329 if (client->state == DHCP_STATE_RENEWING) {
330 err = dhcp_network_send_udp_socket(client->fd,
331 client->lease->server_address,
334 len - DHCP_IP_UDP_SIZE);
336 dhcp_packet_append_ip_headers(request, len);
338 err = dhcp_network_send_raw_socket(client->fd, &client->link,
342 log_dhcp_client(client, "REQUEST");
347 static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now)
349 client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
354 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
356 sd_dhcp_client *client = userdata;
357 usec_t next_timeout = 0;
363 assert(client->event);
365 switch (client->state) {
366 case DHCP_STATE_RENEWING:
368 time_left = (client->lease->t2 - client->lease->t1) / 2;
372 next_timeout = usec + time_left * USEC_PER_SEC;
376 case DHCP_STATE_REBINDING:
378 time_left = (client->lease->lifetime - client->lease->t2) / 2;
382 next_timeout = usec + time_left * USEC_PER_SEC;
385 case DHCP_STATE_INIT:
386 case DHCP_STATE_INIT_REBOOT:
387 case DHCP_STATE_REBOOTING:
388 case DHCP_STATE_SELECTING:
389 case DHCP_STATE_REQUESTING:
390 case DHCP_STATE_BOUND:
392 if (client->attempt < 64)
393 client->attempt *= 2;
395 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
400 next_timeout += (random_u32() & 0x1fffff);
402 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
404 r = sd_event_add_monotonic(client->event,
405 &client->timeout_resend,
408 client_timeout_resend, client);
412 r = sd_event_source_set_priority(client->timeout_resend,
413 client->event_priority);
417 switch (client->state) {
418 case DHCP_STATE_INIT:
420 client_update_secs(client, usec);
422 r = client_send_discover(client, client->secs);
424 client->state = DHCP_STATE_SELECTING;
427 if (client->attempt >= 64)
433 case DHCP_STATE_SELECTING:
434 client_update_secs(client, usec);
436 r = client_send_discover(client, client->secs);
437 if (r < 0 && client->attempt >= 64)
442 case DHCP_STATE_REQUESTING:
443 case DHCP_STATE_RENEWING:
444 case DHCP_STATE_REBINDING:
445 r = client_send_request(client, client->secs);
446 if (r < 0 && client->attempt >= 64)
449 client->request_sent = usec;
453 case DHCP_STATE_INIT_REBOOT:
454 case DHCP_STATE_REBOOTING:
455 case DHCP_STATE_BOUND:
463 client_stop(client, r);
465 /* Errors were dealt with when stopping the client, don't spill
466 errors into the event loop handler */
470 static int client_initialize_events(sd_dhcp_client *client,
471 sd_event_io_handler_t io_callback,
476 assert(client->event);
478 r = sd_event_add_io(client->event, &client->receive_message,
479 client->fd, EPOLLIN, io_callback,
484 r = sd_event_source_set_priority(client->receive_message,
485 client->event_priority);
489 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
491 r = sd_event_add_monotonic(client->event,
492 &client->timeout_resend,
494 client_timeout_resend, client);
498 r = sd_event_source_set_priority(client->timeout_resend,
499 client->event_priority);
503 client_stop(client, r);
509 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
511 sd_dhcp_client *client = userdata;
513 log_dhcp_client(client, "EXPIRED");
515 client_stop(client, DHCP_EVENT_EXPIRED);
520 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
521 sd_dhcp_client *client = userdata;
524 if (client->fd >= 0) {
525 client->receive_message =
526 sd_event_source_unref(client->receive_message);
531 client->state = DHCP_STATE_REBINDING;
534 r = dhcp_network_bind_raw_socket(client->index, &client->link);
536 client_stop(client, r);
542 log_dhcp_client(client, "TIMEOUT T2");
544 return client_initialize_events(client, client_receive_message_raw,
548 static int client_timeout_t1(sd_event_source *s, uint64_t usec,
550 sd_dhcp_client *client = userdata;
553 client->state = DHCP_STATE_RENEWING;
556 r = dhcp_network_bind_udp_socket(client->index,
557 client->lease->address,
560 client_stop(client, r);
566 log_dhcp_client(client, "TIMEOUT T1");
568 return client_initialize_events(client, client_receive_message_udp, usec);
571 static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
573 _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
576 r = dhcp_lease_new(&lease);
580 r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
584 lease->address = offer->yiaddr;
586 if (lease->address == INADDR_ANY ||
587 lease->server_address == INADDR_ANY ||
588 lease->subnet_mask == INADDR_ANY ||
589 lease->lifetime == 0)
592 client->lease = lease;
595 log_dhcp_client(client, "OFFER");
600 static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
602 _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
605 r = dhcp_lease_new(&lease);
609 r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
611 log_dhcp_client(client, "NAK");
612 return DHCP_EVENT_NO_LEASE;
618 lease->address = ack->yiaddr;
620 if (lease->address == INADDR_ANY ||
621 lease->server_address == INADDR_ANY ||
622 lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
625 r = DHCP_EVENT_IP_ACQUIRE;
627 if (client->lease->address != lease->address ||
628 client->lease->subnet_mask != lease->subnet_mask ||
629 client->lease->router != lease->router) {
630 r = DHCP_EVENT_IP_CHANGE;
633 client->lease = sd_dhcp_lease_unref(client->lease);
636 client->lease = lease;
639 log_dhcp_client(client, "ACK");
644 static uint64_t client_compute_timeout(uint64_t request_sent,
646 return request_sent + (lifetime - 3) * USEC_PER_SEC +
647 + (random_u32() & 0x1fffff);
650 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
651 uint64_t next_timeout;
655 assert(client->event);
657 if (client->lease->lifetime < 10)
660 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
661 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
662 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
664 if (!client->lease->t1)
665 client->lease->t1 = client->lease->lifetime / 2;
667 next_timeout = client_compute_timeout(client->request_sent,
669 if (next_timeout < usec)
672 r = sd_event_add_monotonic(client->event,
676 client_timeout_t1, client);
680 r = sd_event_source_set_priority(client->timeout_t1,
681 client->event_priority);
685 if (!client->lease->t2)
686 client->lease->t2 = client->lease->lifetime * 7 / 8;
688 if (client->lease->t2 < client->lease->t1)
691 if (client->lease->lifetime < client->lease->t2)
694 next_timeout = client_compute_timeout(client->request_sent,
696 if (next_timeout < usec)
699 r = sd_event_add_monotonic(client->event,
703 client_timeout_t2, client);
707 r = sd_event_source_set_priority(client->timeout_t2,
708 client->event_priority);
712 next_timeout = client_compute_timeout(client->request_sent,
713 client->lease->lifetime);
714 if (next_timeout < usec)
717 r = sd_event_add_monotonic(client->event,
718 &client->timeout_expire, next_timeout,
720 client_timeout_expire, client);
724 r = sd_event_source_set_priority(client->timeout_expire,
725 client->event_priority);
732 static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
733 int len, usec_t time_now) {
734 int r = 0, notify_event = 0;
737 assert(client->event);
740 if (len < DHCP_MESSAGE_SIZE) {
741 log_dhcp_client(client, "message too small (%d bytes): "
746 if (message->op != BOOTREPLY) {
747 log_dhcp_client(client, "not a BOOTREPLY message: ignoring");
751 if (be32toh(message->xid) != client->xid) {
752 log_dhcp_client(client, "received xid (%u) does not match "
753 "expected (%u): ignoring",
754 be32toh(message->xid), client->xid);
758 if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet,
760 log_dhcp_client(client, "received chaddr does not match "
761 "expected: ignoring");
765 switch (client->state) {
766 case DHCP_STATE_SELECTING:
768 r = client_handle_offer(client, message, len);
771 client->timeout_resend =
772 sd_event_source_unref(client->timeout_resend);
774 client->state = DHCP_STATE_REQUESTING;
777 r = sd_event_add_monotonic(client->event,
778 &client->timeout_resend,
780 client_timeout_resend,
785 r = sd_event_source_set_priority(client->timeout_resend,
786 client->event_priority);
793 case DHCP_STATE_REQUESTING:
794 case DHCP_STATE_RENEWING:
795 case DHCP_STATE_REBINDING:
797 r = client_handle_ack(client, message, len);
799 if (r == DHCP_EVENT_NO_LEASE)
803 client->timeout_resend =
804 sd_event_source_unref(client->timeout_resend);
806 if (client->state == DHCP_STATE_REQUESTING)
807 notify_event = DHCP_EVENT_IP_ACQUIRE;
808 else if (r != DHCP_EVENT_IP_ACQUIRE)
811 client->state = DHCP_STATE_BOUND;
814 client->last_addr = client->lease->address;
816 r = client_set_lease_timeouts(client, time_now);
821 client_notify(client, notify_event);
823 client->receive_message =
824 sd_event_source_unref(client->receive_message);
833 case DHCP_STATE_INIT:
834 case DHCP_STATE_INIT_REBOOT:
835 case DHCP_STATE_REBOOTING:
836 case DHCP_STATE_BOUND:
842 if (r < 0 || r == DHCP_EVENT_NO_LEASE)
843 return client_stop(client, r);
848 static int client_receive_message_udp(sd_event_source *s, int fd,
849 uint32_t revents, void *userdata) {
850 sd_dhcp_client *client = userdata;
851 _cleanup_free_ DHCPMessage *message = NULL;
852 int buflen = 0, len, r;
857 assert(client->event);
859 r = ioctl(fd, FIONREAD, &buflen);
860 if (r < 0 || buflen <= 0)
861 buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE;
863 message = malloc0(buflen);
867 len = read(fd, message, buflen);
871 r = sd_event_get_now_monotonic(client->event, &time_now);
873 return client_stop(client, r);
875 return client_handle_message(client, message, len,
879 static int client_receive_message_raw(sd_event_source *s, int fd,
880 uint32_t revents, void *userdata) {
881 sd_dhcp_client *client = userdata;
882 _cleanup_free_ DHCPPacket *packet = NULL;
883 int buflen = 0, len, r;
888 assert(client->event);
890 r = ioctl(fd, FIONREAD, &buflen);
891 if (r < 0 || buflen <= 0)
892 buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE;
894 packet = malloc0(buflen);
898 len = read(fd, packet, buflen);
902 r = dhcp_packet_verify_headers(packet, len);
906 len -= DHCP_IP_UDP_SIZE;
908 r = sd_event_get_now_monotonic(client->event, &time_now);
910 return client_stop(client, r);
912 return client_handle_message(client, &packet->dhcp, len, time_now);
915 int sd_dhcp_client_start(sd_dhcp_client *client) {
918 assert_return(client, -EINVAL);
919 assert_return(client->event, -EINVAL);
920 assert_return(client->index > 0, -EINVAL);
921 assert_return(client->state == DHCP_STATE_INIT ||
922 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
924 client->xid = random_u32();
926 r = dhcp_network_bind_raw_socket(client->index, &client->link);
929 client_stop(client, r);
934 client->start_time = now(CLOCK_MONOTONIC);
937 log_dhcp_client(client, "STARTED");
939 return client_initialize_events(client, client_receive_message_raw,
943 int sd_dhcp_client_stop(sd_dhcp_client *client) {
944 return client_stop(client, DHCP_EVENT_STOP);
947 int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
951 assert_return(client, -EINVAL);
952 assert_return(!client->event, -EBUSY);
955 client->event = sd_event_ref(event);
957 r = sd_event_default(&client->event);
962 client->event_priority = priority;
967 int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
968 assert_return(client, -EINVAL);
970 client->event = sd_event_unref(client->event);
975 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
979 return client->event;
982 void sd_dhcp_client_free(sd_dhcp_client *client) {
986 sd_dhcp_client_stop(client);
987 sd_dhcp_client_detach_event(client);
989 free(client->req_opts);
993 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
994 #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
996 int sd_dhcp_client_new(sd_dhcp_client **ret) {
997 _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
999 assert_return(ret, -EINVAL);
1001 client = new0(sd_dhcp_client, 1);
1005 client->state = DHCP_STATE_INIT;
1008 client->attempt = 1;
1010 client->req_opts_size = ELEMENTSOF(default_req_opts);
1012 client->req_opts = memdup(default_req_opts, client->req_opts_size);
1013 if (!client->req_opts)