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 log_dhcp_client(client, "set MAC address to "
147 "%02hhx:%02hhx:%02hhx:%02hhx:%02hhx:%02hhx",
148 addr->ether_addr_octet[0],
149 addr->ether_addr_octet[1],
150 addr->ether_addr_octet[2],
151 addr->ether_addr_octet[3],
152 addr->ether_addr_octet[4],
153 addr->ether_addr_octet[5]);
155 memcpy(&client->mac_addr, addr, ETH_ALEN);
160 int sd_dhcp_client_get_lease(sd_dhcp_client *client, sd_dhcp_lease **ret) {
161 assert_return(client, -EINVAL);
162 assert_return(ret, -EINVAL);
164 if (client->state != DHCP_STATE_BOUND &&
165 client->state != DHCP_STATE_RENEWING &&
166 client->state != DHCP_STATE_REBINDING)
167 return -EADDRNOTAVAIL;
169 *ret = sd_dhcp_lease_ref(client->lease);
174 static int client_notify(sd_dhcp_client *client, int event) {
176 client->cb(client, event, client->userdata);
181 static int client_stop(sd_dhcp_client *client, int error) {
182 assert_return(client, -EINVAL);
184 client->receive_message =
185 sd_event_source_unref(client->receive_message);
188 close_nointr_nofail(client->fd);
191 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
193 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
194 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
195 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
199 client_notify(client, error);
201 client->start_time = 0;
203 client->state = DHCP_STATE_INIT;
206 client->lease = sd_dhcp_lease_unref(client->lease);
208 log_dhcp_client(client, "STOPPED");
213 static int client_message_init(sd_dhcp_client *client, DHCPMessage *message,
214 uint8_t type, uint16_t secs, uint8_t **opt,
220 r = dhcp_message_init(message, BOOTREQUEST, client->xid, type, opt,
225 /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
226 refuse to issue an DHCP lease if 'secs' is set to zero */
227 message->secs = htobe16(secs);
229 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
231 if (client->state == DHCP_STATE_RENEWING ||
232 client->state == DHCP_STATE_REBINDING)
233 message->ciaddr = client->lease->address;
235 /* Some DHCP servers will refuse to issue an DHCP lease if the Client
236 Identifier option is not set */
237 r = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
238 ETH_ALEN, &client->mac_addr);
242 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
245 r = dhcp_option_append(opt, optlen,
246 DHCP_OPTION_PARAMETER_REQUEST_LIST,
247 client->req_opts_size,
252 /* Some DHCP servers will send bigger DHCP packets than the
253 defined default size unless the Maximum Messge Size option
254 is explicitely set */
255 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
256 DHCP_MIN_OPTIONS_SIZE);
257 r = dhcp_option_append(opt, optlen,
258 DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
267 static int dhcp_client_send_raw(sd_dhcp_client *client, DHCPPacket *packet,
269 dhcp_packet_append_ip_headers(packet, INADDR_ANY, DHCP_PORT_CLIENT,
270 INADDR_BROADCAST, DHCP_PORT_SERVER, len);
272 return dhcp_network_send_raw_socket(client->fd, &client->link,
276 static int client_send_discover(sd_dhcp_client *client, uint16_t secs) {
278 _cleanup_free_ DHCPPacket *discover;
282 optlen = DHCP_MIN_OPTIONS_SIZE;
283 len = sizeof(DHCPPacket) + optlen;
285 discover = malloc0(len);
290 err = client_message_init(client, &discover->dhcp, DHCP_DISCOVER,
291 secs, &opt, &optlen);
295 if (client->last_addr != INADDR_ANY) {
296 err = dhcp_option_append(&opt, &optlen,
297 DHCP_OPTION_REQUESTED_IP_ADDRESS,
298 4, &client->last_addr);
303 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
307 err = dhcp_client_send_raw(client, discover, len);
311 log_dhcp_client(client, "DISCOVER");
316 static int client_send_request(sd_dhcp_client *client, uint16_t secs) {
317 _cleanup_free_ DHCPPacket *request;
322 optlen = DHCP_MIN_OPTIONS_SIZE;
323 len = sizeof(DHCPPacket) + optlen;
325 request = malloc0(len);
329 err = client_message_init(client, &request->dhcp, DHCP_REQUEST, secs,
334 if (client->state == DHCP_STATE_REQUESTING) {
335 err = dhcp_option_append(&opt, &optlen,
336 DHCP_OPTION_REQUESTED_IP_ADDRESS,
337 4, &client->lease->address);
341 err = dhcp_option_append(&opt, &optlen,
342 DHCP_OPTION_SERVER_IDENTIFIER,
343 4, &client->lease->server_address);
348 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
352 if (client->state == DHCP_STATE_RENEWING) {
353 err = dhcp_network_send_udp_socket(client->fd,
354 client->lease->server_address,
357 len - DHCP_IP_UDP_SIZE);
359 err = dhcp_client_send_raw(client, request, len);
364 log_dhcp_client(client, "REQUEST");
369 static uint16_t client_update_secs(sd_dhcp_client *client, usec_t time_now)
371 client->secs = ((time_now - client->start_time) / USEC_PER_SEC) ? : 1;
376 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
378 sd_dhcp_client *client = userdata;
379 usec_t next_timeout = 0;
386 assert(client->event);
388 r = sd_event_get_now_monotonic(client->event, &time_now);
392 switch (client->state) {
393 case DHCP_STATE_RENEWING:
395 time_left = (client->lease->t2 - client->lease->t1) / 2;
399 next_timeout = time_now + time_left * USEC_PER_SEC;
403 case DHCP_STATE_REBINDING:
405 time_left = (client->lease->lifetime - client->lease->t2) / 2;
409 next_timeout = time_now + time_left * USEC_PER_SEC;
412 case DHCP_STATE_INIT:
413 case DHCP_STATE_INIT_REBOOT:
414 case DHCP_STATE_REBOOTING:
415 case DHCP_STATE_SELECTING:
416 case DHCP_STATE_REQUESTING:
417 case DHCP_STATE_BOUND:
419 if (client->attempt < 64)
420 client->attempt *= 2;
422 next_timeout = time_now + (client->attempt - 1) * USEC_PER_SEC;
427 next_timeout += (random_u32() & 0x1fffff);
429 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
431 r = sd_event_add_monotonic(client->event,
432 &client->timeout_resend,
435 client_timeout_resend, client);
439 r = sd_event_source_set_priority(client->timeout_resend,
440 client->event_priority);
444 switch (client->state) {
445 case DHCP_STATE_INIT:
447 client_update_secs(client, time_now);
449 r = client_send_discover(client, client->secs);
451 client->state = DHCP_STATE_SELECTING;
454 if (client->attempt >= 64)
460 case DHCP_STATE_SELECTING:
461 client_update_secs(client, time_now);
463 r = client_send_discover(client, client->secs);
464 if (r < 0 && client->attempt >= 64)
469 case DHCP_STATE_REQUESTING:
470 case DHCP_STATE_RENEWING:
471 case DHCP_STATE_REBINDING:
472 r = client_send_request(client, client->secs);
473 if (r < 0 && client->attempt >= 64)
476 client->request_sent = time_now;
480 case DHCP_STATE_INIT_REBOOT:
481 case DHCP_STATE_REBOOTING:
482 case DHCP_STATE_BOUND:
490 client_stop(client, r);
492 /* Errors were dealt with when stopping the client, don't spill
493 errors into the event loop handler */
497 static int client_initialize_events(sd_dhcp_client *client,
498 sd_event_io_handler_t io_callback) {
502 assert(client->event);
504 r = sd_event_add_io(client->event, &client->receive_message,
505 client->fd, EPOLLIN, io_callback,
510 r = sd_event_source_set_priority(client->receive_message,
511 client->event_priority);
515 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
517 r = sd_event_add_monotonic(client->event,
518 &client->timeout_resend, 0, 0,
519 client_timeout_resend, client);
523 r = sd_event_source_set_priority(client->timeout_resend,
524 client->event_priority);
528 client_stop(client, r);
534 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
536 sd_dhcp_client *client = userdata;
538 log_dhcp_client(client, "EXPIRED");
540 client_stop(client, DHCP_EVENT_EXPIRED);
545 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata) {
546 sd_dhcp_client *client = userdata;
549 if (client->fd >= 0) {
550 client->receive_message =
551 sd_event_source_unref(client->receive_message);
552 close_nointr_nofail(client->fd);
556 client->state = DHCP_STATE_REBINDING;
559 r = dhcp_network_bind_raw_socket(client->index, &client->link);
561 client_stop(client, r);
567 log_dhcp_client(client, "TIMEOUT T2");
569 return client_initialize_events(client, client_receive_message_raw);
572 static int client_timeout_t1(sd_event_source *s, uint64_t usec,
574 sd_dhcp_client *client = userdata;
577 client->state = DHCP_STATE_RENEWING;
580 r = dhcp_network_bind_udp_socket(client->index,
581 client->lease->address,
584 client_stop(client, r);
590 log_dhcp_client(client, "TIMEOUT T1");
592 return client_initialize_events(client, client_receive_message_udp);
595 static int client_handle_offer(sd_dhcp_client *client, DHCPMessage *offer,
597 _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
600 r = dhcp_lease_new(&lease);
604 r = dhcp_option_parse(offer, len, dhcp_lease_parse_options, lease);
608 lease->next_server = offer->siaddr;
610 lease->address = offer->yiaddr;
612 if (lease->address == INADDR_ANY ||
613 lease->server_address == INADDR_ANY ||
614 lease->subnet_mask == INADDR_ANY ||
615 lease->lifetime == 0)
618 client->lease = lease;
621 log_dhcp_client(client, "OFFER");
626 static int client_handle_ack(sd_dhcp_client *client, DHCPMessage *ack,
628 _cleanup_dhcp_lease_unref_ sd_dhcp_lease *lease = NULL;
631 r = dhcp_lease_new(&lease);
635 r = dhcp_option_parse(ack, len, dhcp_lease_parse_options, lease);
637 log_dhcp_client(client, "NAK");
638 return DHCP_EVENT_NO_LEASE;
644 lease->next_server = ack->siaddr;
646 lease->address = ack->yiaddr;
648 if (lease->address == INADDR_ANY ||
649 lease->server_address == INADDR_ANY ||
650 lease->subnet_mask == INADDR_ANY || lease->lifetime == 0)
653 r = DHCP_EVENT_IP_ACQUIRE;
655 if (client->lease->address != lease->address ||
656 client->lease->subnet_mask != lease->subnet_mask ||
657 client->lease->router != lease->router) {
658 r = DHCP_EVENT_IP_CHANGE;
661 client->lease = sd_dhcp_lease_unref(client->lease);
664 client->lease = lease;
667 log_dhcp_client(client, "ACK");
672 static uint64_t client_compute_timeout(uint64_t request_sent,
674 return request_sent + (lifetime - 3) * USEC_PER_SEC +
675 + (random_u32() & 0x1fffff);
678 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec) {
679 uint64_t next_timeout;
683 assert(client->event);
685 if (client->lease->lifetime < 10)
688 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
689 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
690 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
692 if (!client->lease->t1)
693 client->lease->t1 = client->lease->lifetime / 2;
695 next_timeout = client_compute_timeout(client->request_sent,
697 if (next_timeout < usec)
700 r = sd_event_add_monotonic(client->event,
704 client_timeout_t1, client);
708 r = sd_event_source_set_priority(client->timeout_t1,
709 client->event_priority);
713 if (!client->lease->t2)
714 client->lease->t2 = client->lease->lifetime * 7 / 8;
716 if (client->lease->t2 < client->lease->t1)
719 if (client->lease->lifetime < client->lease->t2)
722 next_timeout = client_compute_timeout(client->request_sent,
724 if (next_timeout < usec)
727 r = sd_event_add_monotonic(client->event,
731 client_timeout_t2, client);
735 r = sd_event_source_set_priority(client->timeout_t2,
736 client->event_priority);
740 next_timeout = client_compute_timeout(client->request_sent,
741 client->lease->lifetime);
742 if (next_timeout < usec)
745 r = sd_event_add_monotonic(client->event,
746 &client->timeout_expire, next_timeout,
748 client_timeout_expire, client);
752 r = sd_event_source_set_priority(client->timeout_expire,
753 client->event_priority);
760 static int client_handle_message(sd_dhcp_client *client, DHCPMessage *message,
761 int len, usec_t time_now) {
762 int r = 0, notify_event = 0;
765 assert(client->event);
768 if (len < DHCP_MESSAGE_SIZE) {
769 log_dhcp_client(client, "message too small (%d bytes): "
774 if (message->op != BOOTREPLY) {
775 log_dhcp_client(client, "not a BOOTREPLY message: ignoring");
779 if (be32toh(message->xid) != client->xid) {
780 log_dhcp_client(client, "received xid (%u) does not match "
781 "expected (%u): ignoring",
782 be32toh(message->xid), client->xid);
786 if (memcmp(&message->chaddr[0], &client->mac_addr.ether_addr_octet,
788 log_dhcp_client(client, "received chaddr does not match "
789 "expected: ignoring");
793 switch (client->state) {
794 case DHCP_STATE_SELECTING:
796 r = client_handle_offer(client, message, len);
799 client->timeout_resend =
800 sd_event_source_unref(client->timeout_resend);
802 client->state = DHCP_STATE_REQUESTING;
805 r = sd_event_add_monotonic(client->event,
806 &client->timeout_resend, 0,
807 0, client_timeout_resend,
812 r = sd_event_source_set_priority(client->timeout_resend,
813 client->event_priority);
820 case DHCP_STATE_REQUESTING:
821 case DHCP_STATE_RENEWING:
822 case DHCP_STATE_REBINDING:
824 r = client_handle_ack(client, message, len);
826 if (r == DHCP_EVENT_NO_LEASE)
830 client->timeout_resend =
831 sd_event_source_unref(client->timeout_resend);
833 if (client->state == DHCP_STATE_REQUESTING)
834 notify_event = DHCP_EVENT_IP_ACQUIRE;
835 else if (r != DHCP_EVENT_IP_ACQUIRE)
838 client->state = DHCP_STATE_BOUND;
841 client->last_addr = client->lease->address;
843 r = client_set_lease_timeouts(client, time_now);
848 client_notify(client, notify_event);
850 client->receive_message =
851 sd_event_source_unref(client->receive_message);
852 close_nointr_nofail(client->fd);
860 case DHCP_STATE_INIT:
861 case DHCP_STATE_INIT_REBOOT:
862 case DHCP_STATE_REBOOTING:
863 case DHCP_STATE_BOUND:
869 if (r < 0 || r == DHCP_EVENT_NO_LEASE)
870 return client_stop(client, r);
875 static int client_receive_message_udp(sd_event_source *s, int fd,
876 uint32_t revents, void *userdata) {
877 sd_dhcp_client *client = userdata;
878 _cleanup_free_ DHCPMessage *message = NULL;
879 int buflen = 0, len, r;
884 assert(client->event);
886 r = ioctl(fd, FIONREAD, &buflen);
887 if (r < 0 || buflen <= 0)
888 buflen = sizeof(DHCPMessage) + DHCP_MIN_OPTIONS_SIZE;
890 message = malloc0(buflen);
894 len = read(fd, message, buflen);
898 r = sd_event_get_now_monotonic(client->event, &time_now);
900 return client_stop(client, r);
902 return client_handle_message(client, message, len,
906 static int client_receive_message_raw(sd_event_source *s, int fd,
907 uint32_t revents, void *userdata) {
908 sd_dhcp_client *client = userdata;
909 _cleanup_free_ DHCPPacket *packet = NULL;
911 uint8_t cmsgbuf[CMSG_LEN(sizeof(struct tpacket_auxdata))];
912 struct iovec iov = {};
913 struct msghdr msg = {
916 .msg_control = cmsgbuf,
917 .msg_controllen = sizeof(cmsgbuf),
919 struct cmsghdr *cmsg;
920 bool checksum = true;
921 int buflen = 0, len, r;
925 assert(client->event);
927 r = ioctl(fd, FIONREAD, &buflen);
928 if (r < 0 || buflen <= 0)
929 buflen = sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE;
931 packet = malloc0(buflen);
935 iov.iov_base = packet;
936 iov.iov_len = buflen;
938 len = recvmsg(fd, &msg, 0);
940 log_dhcp_client(client, "could not receive message from raw "
941 "socket: %s", strerror(errno));
945 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
946 if (cmsg->cmsg_level == SOL_PACKET && cmsg->cmsg_type == PACKET_AUXDATA) {
947 struct tpacket_auxdata *aux = (void *)CMSG_DATA(cmsg);
949 checksum = !(aux->tp_status & TP_STATUS_CSUMNOTREADY);
954 r = dhcp_packet_verify_headers(packet, len, checksum);
958 len -= DHCP_IP_UDP_SIZE;
960 r = sd_event_get_now_monotonic(client->event, &time_now);
962 return client_stop(client, r);
964 return client_handle_message(client, &packet->dhcp, len, time_now);
967 int sd_dhcp_client_start(sd_dhcp_client *client) {
970 assert_return(client, -EINVAL);
971 assert_return(client->event, -EINVAL);
972 assert_return(client->index > 0, -EINVAL);
973 assert_return(client->state == DHCP_STATE_INIT ||
974 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
976 client->xid = random_u32();
978 r = dhcp_network_bind_raw_socket(client->index, &client->link);
981 client_stop(client, r);
986 client->start_time = now(CLOCK_MONOTONIC);
989 log_dhcp_client(client, "STARTED");
991 return client_initialize_events(client, client_receive_message_raw);
994 int sd_dhcp_client_stop(sd_dhcp_client *client) {
995 return client_stop(client, DHCP_EVENT_STOP);
998 int sd_dhcp_client_attach_event(sd_dhcp_client *client, sd_event *event,
1002 assert_return(client, -EINVAL);
1003 assert_return(!client->event, -EBUSY);
1006 client->event = sd_event_ref(event);
1008 r = sd_event_default(&client->event);
1013 client->event_priority = priority;
1018 int sd_dhcp_client_detach_event(sd_dhcp_client *client) {
1019 assert_return(client, -EINVAL);
1021 client->event = sd_event_unref(client->event);
1026 sd_event *sd_dhcp_client_get_event(sd_dhcp_client *client) {
1030 return client->event;
1033 void sd_dhcp_client_free(sd_dhcp_client *client) {
1037 sd_dhcp_client_stop(client);
1038 sd_dhcp_client_detach_event(client);
1040 free(client->req_opts);
1044 DEFINE_TRIVIAL_CLEANUP_FUNC(sd_dhcp_client*, sd_dhcp_client_free);
1045 #define _cleanup_dhcp_client_free_ _cleanup_(sd_dhcp_client_freep)
1047 int sd_dhcp_client_new(sd_dhcp_client **ret) {
1048 _cleanup_dhcp_client_free_ sd_dhcp_client *client = NULL;
1050 assert_return(ret, -EINVAL);
1052 client = new0(sd_dhcp_client, 1);
1056 client->state = DHCP_STATE_INIT;
1059 client->attempt = 1;
1061 client->req_opts_size = ELEMENTSOF(default_req_opts);
1063 client->req_opts = memdup(default_req_opts, client->req_opts_size);
1064 if (!client->req_opts)