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-internal.h"
33 #include "dhcp-lease-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,
211 r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt,
216 /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
217 refuse to issue an DHCP lease if 'secs' is set to zero */
218 message->secs = htobe16(secs);
220 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
222 if (client->state == DHCP_STATE_RENEWING ||
223 client->state == DHCP_STATE_REBINDING)
224 message->ciaddr = client->lease->address;
226 /* Some DHCP servers will refuse to issue an DHCP lease if the Client
227 Identifier option is not set */
228 r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
229 ETH_ALEN, &client->mac_addr);
233 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
236 r = dhcp_option_append(opt, optlen,
237 DHCP_OPTION_PARAMETER_REQUEST_LIST,
238 client->req_opts_size,
243 /* Some DHCP servers will send bigger DHCP packets than the
244 defined default size unless the Maximum Messge Size option
245 is explicitely set */
246 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
247 DHCP_MIN_OPTIONS_SIZE);
248 r = dhcp_option_append(opt, optlen,
249 DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
258 static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
260 _cleanup_free_ DHCPPacket *discover;
264 optlen = DHCP_MIN_OPTIONS_SIZE;
265 len = sizeof(DHCPPacket) + optlen;
267 discover = malloc0(len);
272 err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
273 secs, &opt, &optlen);
277 if (client->last_addr != INADDR_ANY) {
278 err = dhcp_option_append(&opt, &optlen,
279 DHCP_OPTION_REQUESTED_IP_ADDRESS,
280 4, &client->last_addr);
285 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
289 dhcp_packet_append_ip_headers(discover, len);
291 err = dhcp_network_send_raw_socket(client->fd, &client->link,
294 log_dhcp_client(client, "DISCOVER");
299 static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
300 _cleanup_free_ DHCPPacket *request;
305 optlen = DHCP_MIN_OPTIONS_SIZE;
306 len = sizeof(DHCPPacket) + optlen;
308 request = malloc0(len);
312 err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs,
317 if (client->state == DHCP_STATE_REQUESTING) {
318 err = dhcp_option_append(&opt, &optlen,
319 DHCP_OPTION_REQUESTED_IP_ADDRESS,
320 4, &client->lease->address);
324 err = dhcp_option_append(&opt, &optlen,
325 DHCP_OPTION_SERVER_IDENTIFIER,
326 4, &client->lease->server_address);
331 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
335 if (client->state == DHCP_STATE_RENEWING) {
336 err = dhcp_network_send_udp_socket(client->fd,
337 client->lease->server_address,
340 len - DHCP_IP_UDP_SIZE);
342 dhcp_packet_append_ip_headers(request, len);
344 err = dhcp_network_send_raw_socket(client->fd, &client->link,
348 log_dhcp_client(client, "REQUEST");
353 static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now)
355 client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
360 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
362 sd_dhcp_client *client = userdata;
363 usec_t next_timeout = 0;
369 assert(client->event);
371 switch (client->state) {
372 case DHCP_STATE_RENEWING:
374 time_left = (client->lease->t2 - client->lease->t1) / 2;
378 next_timeout = usec + time_left * USEC_PER_SEC;
382 case DHCP_STATE_REBINDING:
384 time_left = (client->lease->lifetime - client->lease->t2) / 2;
388 next_timeout = usec + time_left * USEC_PER_SEC;
391 case DHCP_STATE_INIT:
392 case DHCP_STATE_INIT_REBOOT:
393 case DHCP_STATE_REBOOTING:
394 case DHCP_STATE_SELECTING:
395 case DHCP_STATE_REQUESTING:
396 case DHCP_STATE_BOUND:
398 if (client->attempt < 64)
399 client->attempt *= 2;
401 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
406 next_timeout += (random_u32() & 0x1fffff);
408 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
410 r = sd_event_add_monotonic(client->event,
411 &client->timeout_resend,
414 client_timeout_resend, client);
418 r = sd_event_source_set_priority(client->timeout_resend,
419 client->event_priority);
423 switch (client->state) {
424 case DHCP_STATE_INIT:
426 client_update_secs(client, usec);
428 r = client_send_discover(client, client->secs);
430 client->state = DHCP_STATE_SELECTING;
433 if (client->attempt >= 64)
439 case DHCP_STATE_SELECTING:
440 client_update_secs(client, usec);
442 r = client_send_discover(client, client->secs);
443 if (r < 0 && client->attempt >= 64)
448 case DHCP_STATE_REQUESTING:
449 case DHCP_STATE_RENEWING:
450 case DHCP_STATE_REBINDING:
451 r = client_send_request(client, client->secs);
452 if (r < 0 && client->attempt >= 64)
455 client->request_sent = usec;
459 case DHCP_STATE_INIT_REBOOT:
460 case DHCP_STATE_REBOOTING:
461 case DHCP_STATE_BOUND:
469 client_stop(client, r);
471 /* Errors were dealt with when stopping the client, don't spill
472 errors into the event loop handler */
476 static int client_initialize_events(sd_dhcp_client *client,
477 sd_event_io_handler_t io_callback,
482 assert(client->event);
484 r = sd_event_add_io(client->event, &client->receive_message,
485 client->fd, EPOLLIN, io_callback,
490 r = sd_event_source_set_priority(client->receive_message,
491 client->event_priority);
495 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
497 r = sd_event_add_monotonic(client->event,
498 &client->timeout_resend,
500 client_timeout_resend, client);
504 r = sd_event_source_set_priority(client->timeout_resend,
505 client->event_priority);
509 client_stop(client, r);
515 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
517 sd_dhcp_client *client = userdata;
519 log_dhcp_client(client, "EXPIRED");
521 client_stop(client, DHCP_EVENT_EXPIRED);
526 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
527 sd_dhcp_client *client = userdata;
530 if (client->fd >= 0) {
531 client->receive_message =
532 sd_event_source_unref(client->receive_message);
537 client->state = DHCP_STATE_REBINDING;
540 r = dhcp_network_bind_raw_socket(client->index, &client->link);
542 client_stop(client, r);
548 log_dhcp_client(client, "TIMEOUT T2");
550 return client_initialize_events(client, client_receive_message_raw,
554 static int client_timeout_t1(sd_event_source *s, uint64_t usec,
556 sd_dhcp_client *client = userdata;
559 client->state = DHCP_STATE_RENEWING;
562 r = dhcp_network_bind_udp_socket(client->index,
563 client->lease->address,
566 client_stop(client, r);
572 log_dhcp_client(client, "TIMEOUT T1");
574 return client_initialize_events(client, client_receive_message_udp, usec);
577 static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
579 _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
582 r = dhcp_lease_new(&lease);
586 r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
590 lease->next_server = offer->siaddr;
592 lease->address = offer->yiaddr;
594 if (lease->address == INADDR_ANY ||
595 lease->server_address == INADDR_ANY ||
596 lease->subnet_mask == INADDR_ANY ||
597 lease->lifetime == 0)
600 client->lease = lease;
603 log_dhcp_client(client, "OFFER");
608 static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
610 _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
613 r = dhcp_lease_new(&lease);
617 r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
619 log_dhcp_client(client, "NAK");
620 return DHCP_EVENT_NO_LEASE;
626 lease->next_server = ack->siaddr;
628 lease->address = ack->yiaddr;
630 if (lease->address == INADDR_ANY ||
631 lease->server_address == INADDR_ANY ||
632 lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
635 r = DHCP_EVENT_IP_ACQUIRE;
637 if (client->lease->address != lease->address ||
638 client->lease->subnet_mask != lease->subnet_mask ||
639 client->lease->router != lease->router) {
640 r = DHCP_EVENT_IP_CHANGE;
643 client->lease = sd_dhcp_lease_unref(client->lease);
646 client->lease = lease;
649 log_dhcp_client(client, "ACK");
654 static uint64_t client_compute_timeout(uint64_t request_sent,
656 return request_sent + (lifetime - 3) * USEC_PER_SEC +
657 + (random_u32() & 0x1fffff);
660 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
661 uint64_t next_timeout;
665 assert(client->event);
667 if (client->lease->lifetime < 10)
670 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
671 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
672 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
674 if (!client->lease->t1)
675 client->lease->t1 = client->lease->lifetime / 2;
677 next_timeout = client_compute_timeout(client->request_sent,
679 if (next_timeout < usec)
682 r = sd_event_add_monotonic(client->event,
686 client_timeout_t1, client);
690 r = sd_event_source_set_priority(client->timeout_t1,
691 client->event_priority);
695 if (!client->lease->t2)
696 client->lease->t2 = client->lease->lifetime * 7 / 8;
698 if (client->lease->t2 < client->lease->t1)
701 if (client->lease->lifetime < client->lease->t2)
704 next_timeout = client_compute_timeout(client->request_sent,
706 if (next_timeout < usec)
709 r = sd_event_add_monotonic(client->event,
713 client_timeout_t2, client);
717 r = sd_event_source_set_priority(client->timeout_t2,
718 client->event_priority);
722 next_timeout = client_compute_timeout(client->request_sent,
723 client->lease->lifetime);
724 if (next_timeout < usec)
727 r = sd_event_add_monotonic(client->event,
728 &client->timeout_expire, next_timeout,
730 client_timeout_expire, client);
734 r = sd_event_source_set_priority(client->timeout_expire,
735 client->event_priority);
742 static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
743 int len, usec_t time_now) {
744 int r = 0, notify_event = 0;
747 assert(client->event);
750 if (len < DHCP_MESSAGE_SIZE) {
751 log_dhcp_client(client, "message too small (%d bytes): "
756 if (message->op != BOOTREPLY) {
757 log_dhcp_client(client, "not a BOOTREPLY message: ignoring");
761 if (be32toh(message->xid) != client->xid) {
762 log_dhcp_client(client, "received xid (%u) does not match "
763 "expected (%u): ignoring",
764 be32toh(message->xid), client->xid);
768 if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet,
770 log_dhcp_client(client, "received chaddr does not match "
771 "expected: ignoring");
775 switch (client->state) {
776 case DHCP_STATE_SELECTING:
778 r = client_handle_offer(client, message, len);
781 client->timeout_resend =
782 sd_event_source_unref(client->timeout_resend);
784 client->state = DHCP_STATE_REQUESTING;
787 r = sd_event_add_monotonic(client->event,
788 &client->timeout_resend,
790 client_timeout_resend,
795 r = sd_event_source_set_priority(client->timeout_resend,
796 client->event_priority);
803 case DHCP_STATE_REQUESTING:
804 case DHCP_STATE_RENEWING:
805 case DHCP_STATE_REBINDING:
807 r = client_handle_ack(client, message, len);
809 if (r == DHCP_EVENT_NO_LEASE)
813 client->timeout_resend =
814 sd_event_source_unref(client->timeout_resend);
816 if (client->state == DHCP_STATE_REQUESTING)
817 notify_event = DHCP_EVENT_IP_ACQUIRE;
818 else if (r != DHCP_EVENT_IP_ACQUIRE)
821 client->state = DHCP_STATE_BOUND;
824 client->last_addr = client->lease->address;
826 r = client_set_lease_timeouts(client, time_now);
831 client_notify(client, notify_event);
833 client->receive_message =
834 sd_event_source_unref(client->receive_message);
843 case DHCP_STATE_INIT:
844 case DHCP_STATE_INIT_REBOOT:
845 case DHCP_STATE_REBOOTING:
846 case DHCP_STATE_BOUND:
852 if (r < 0 || r == DHCP_EVENT_NO_LEASE)
853 return client_stop(client, r);
858 static int client_receive_message_udp(sd_event_source *s, int fd,
859 uint32_t revents, void *userdata) {
860 sd_dhcp_client *client = userdata;
861 _cleanup_free_ DHCPMessage *message = NULL;
862 int buflen = 0, len, r;
867 assert(client->event);
869 r = ioctl(fd, FIONREAD, &buflen);
870 if (r < 0 || buflen <= 0)
871 buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE;
873 message = malloc0(buflen);
877 len = read(fd, message, buflen);
881 r = sd_event_get_now_monotonic(client->event, &time_now);
883 return client_stop(client, r);
885 return client_handle_message(client, message, len,
889 static int client_receive_message_raw(sd_event_source *s, int fd,
890 uint32_t revents, void *userdata) {
891 sd_dhcp_client *client = userdata;
892 _cleanup_free_ DHCPPacket *packet = NULL;
894 uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
895 struct iovec iov = {};
896 struct msghdr msg = {
899 .msg_control = cmsgbuf,
900 .msg_controllen = sizeof(cmsgbuf),
902 struct cmsghdr *cmsg;
903 bool checksum = true;
904 int buflen = 0, len, r;
908 assert(client->event);
910 r = ioctl(fd, FIONREAD, &buflen);
911 if (r < 0 || buflen <= 0)
912 buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE;
914 packet = malloc0(buflen);
918 iov.iov_base = packet;
919 iov.iov_len = buflen;
921 len = recvmsg(fd, &msg, 0);
923 log_dhcp_client(client, "could not receive message from raw "
924 "socket: %s", strerror(errno));
928 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
929 if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA) {
930 struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
932 checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY);
937 r = dhcp_packet_verify_headers(packet, len, checksum);
941 len -= DHCP_IP_UDP_SIZE;
943 r = sd_event_get_now_monotonic(client->event, &time_now);
945 return client_stop(client, r);
947 return client_handle_message(client, &packet->dhcp, len, time_now);
950 int sd_dhcp_client_start(sd_dhcp_client *client) {
953 assert_return(client, -EINVAL);
954 assert_return(client->event, -EINVAL);
955 assert_return(client->index > 0, -EINVAL);
956 assert_return(client->state == DHCP_STATE_INIT ||
957 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
959 client->xid = random_u32();
961 r = dhcp_network_bind_raw_socket(client->index, &client->link);
964 client_stop(client, r);
969 client->start_time = now(CLOCK_MONOTONIC);
972 log_dhcp_client(client, "STARTED");
974 return client_initialize_events(client, client_receive_message_raw,
978 int sd_dhcp_client_stop(sd_dhcp_client *client) {
979 return client_stop(client, DHCP_EVENT_STOP);
982 int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
986 assert_return(client, -EINVAL);
987 assert_return(!client->event, -EBUSY);
990 client->event = sd_event_ref(event);
992 r = sd_event_default(&client->event);
997 client->event_priority = priority;
1002 int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
1003 assert_return(client, -EINVAL);
1005 client->event = sd_event_unref(client->event);
1010 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
1014 return client->event;
1017 void sd_dhcp_client_free(sd_dhcp_client *client) {
1021 sd_dhcp_client_stop(client);
1022 sd_dhcp_client_detach_event(client);
1024 free(client->req_opts);
1028 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
1029 #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
1031 int sd_dhcp_client_new(sd_dhcp_client **ret) {
1032 _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
1034 assert_return(ret, -EINVAL);
1036 client = new0(sd_dhcp_client, 1);
1040 client->state = DHCP_STATE_INIT;
1043 client->attempt = 1;
1045 client->req_opts_size = ELEMENTSOF(default_req_opts);
1047 client->req_opts = memdup(default_req_opts, client->req_opts_size);
1048 if (!client->req_opts)