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>
29 #include "dhcp-protocol.h"
30 #include "dhcp-internal.h"
31 #include "sd-dhcp-client.h"
33 #define DHCP_CLIENT_MIN_OPTIONS_SIZE 312
40 be32_t server_address;
45 typedef struct DHCPLease DHCPLease;
47 struct sd_dhcp_client {
50 sd_event_source *timeout_resend;
53 union sockaddr_union link;
54 sd_event_source *receive_message;
58 struct ether_addr mac_addr;
63 sd_event_source *timeout_t1;
64 sd_event_source *timeout_t2;
65 sd_event_source *timeout_expire;
66 sd_dhcp_client_cb_t cb;
71 static const uint8_t default_req_opts[] = {
72 DHCP_OPTION_SUBNET_MASK,
74 DHCP_OPTION_HOST_NAME,
75 DHCP_OPTION_DOMAIN_NAME,
76 DHCP_OPTION_DOMAIN_NAME_SERVER,
77 DHCP_OPTION_NTP_SERVER,
80 int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
83 assert_return(client, -EINVAL);
86 client->userdata = userdata;
91 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option)
95 assert_return(client, -EINVAL);
96 assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
100 case DHCP_OPTION_OVERLOAD:
101 case DHCP_OPTION_MESSAGE_TYPE:
102 case DHCP_OPTION_PARAMETER_REQUEST_LIST:
103 case DHCP_OPTION_END:
110 for (i = 0; i < client->req_opts_size; i++)
111 if (client->req_opts[i] == option)
114 if (!GREEDY_REALLOC(client->req_opts, client->req_opts_size,
115 client->req_opts_size + 1))
118 client->req_opts[client->req_opts_size - 1] = option;
123 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
124 const struct in_addr *last_addr)
126 assert_return(client, -EINVAL);
127 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
130 client->last_addr = last_addr->s_addr;
132 client->last_addr = INADDR_ANY;
137 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index)
139 assert_return(client, -EINVAL);
140 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
141 assert_return(interface_index >= -1, -EINVAL);
143 client->index = interface_index;
148 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
149 const struct ether_addr *addr)
151 assert_return(client, -EINVAL);
152 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
154 memcpy(&client->mac_addr, addr, ETH_ALEN);
159 int sd_dhcp_client_get_address(sd_dhcp_client *client, struct in_addr *addr)
161 assert_return(client, -EINVAL);
162 assert_return(addr, -EINVAL);
164 switch (client->state) {
165 case DHCP_STATE_INIT:
166 case DHCP_STATE_SELECTING:
167 case DHCP_STATE_INIT_REBOOT:
168 case DHCP_STATE_REBOOTING:
169 case DHCP_STATE_REQUESTING:
170 return -EADDRNOTAVAIL;
172 case DHCP_STATE_BOUND:
173 case DHCP_STATE_RENEWING:
174 case DHCP_STATE_REBINDING:
175 addr->s_addr = client->lease->address;
183 int sd_dhcp_client_get_netmask(sd_dhcp_client *client, struct in_addr *addr)
185 assert_return(client, -EINVAL);
186 assert_return(addr, -EINVAL);
188 switch (client->state) {
189 case DHCP_STATE_INIT:
190 case DHCP_STATE_SELECTING:
191 case DHCP_STATE_INIT_REBOOT:
192 case DHCP_STATE_REBOOTING:
193 case DHCP_STATE_REQUESTING:
194 return -EADDRNOTAVAIL;
196 case DHCP_STATE_BOUND:
197 case DHCP_STATE_RENEWING:
198 case DHCP_STATE_REBINDING:
199 addr->s_addr = client->lease->subnet_mask;
207 int sd_dhcp_client_prefixlen(const struct in_addr *addr)
212 assert_return(addr, -EADDRNOTAVAIL);
214 mask = be32toh(addr->s_addr);
223 int sd_dhcp_client_get_router(sd_dhcp_client *client, struct in_addr *addr)
225 assert_return(client, -EINVAL);
226 assert_return(addr, -EINVAL);
228 switch (client->state) {
229 case DHCP_STATE_INIT:
230 case DHCP_STATE_SELECTING:
231 case DHCP_STATE_INIT_REBOOT:
232 case DHCP_STATE_REBOOTING:
233 case DHCP_STATE_REQUESTING:
234 return -EADDRNOTAVAIL;
236 case DHCP_STATE_BOUND:
237 case DHCP_STATE_RENEWING:
238 case DHCP_STATE_REBINDING:
239 addr->s_addr = client->lease->router;
247 static int client_notify(sd_dhcp_client *client, int event)
250 client->cb(client, event, client->userdata);
255 static int client_stop(sd_dhcp_client *client, int error)
257 assert_return(client, -EINVAL);
258 assert_return(client->state != DHCP_STATE_INIT &&
259 client->state != DHCP_STATE_INIT_REBOOT, -EALREADY);
261 client->receive_message =
262 sd_event_source_unref(client->receive_message);
268 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
270 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
271 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
272 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
276 client_notify(client, error);
278 switch (client->state) {
280 case DHCP_STATE_INIT:
281 case DHCP_STATE_SELECTING:
282 case DHCP_STATE_REQUESTING:
283 case DHCP_STATE_BOUND:
285 client->start_time = 0;
286 client->state = DHCP_STATE_INIT;
289 case DHCP_STATE_INIT_REBOOT:
290 case DHCP_STATE_REBOOTING:
291 case DHCP_STATE_RENEWING:
292 case DHCP_STATE_REBINDING:
299 client->lease = NULL;
305 static int client_packet_init(sd_dhcp_client *client, uint8_t type,
306 DHCPMessage *message, uint16_t secs,
307 uint8_t **opt, size_t *optlen)
312 *opt = (uint8_t *)(message + 1);
318 message->op = BOOTREQUEST;
320 message->hlen = ETHER_ADDR_LEN;
321 message->xid = htobe32(client->xid);
323 /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
324 refuse to issue an DHCP lease if 'secs' is set to zero */
325 message->secs = htobe16(secs);
327 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
335 err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
340 /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
341 Identifier option is not set */
342 err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
343 ETH_ALEN, &client->mac_addr);
347 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
348 err = dhcp_option_append(opt, optlen,
349 DHCP_OPTION_PARAMETER_REQUEST_LIST,
350 client->req_opts_size,
355 /* Some DHCP servers will send bigger DHCP packets than the
356 defined default size unless the Maximum Messge Size option
357 is explicitely set */
358 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
359 DHCP_CLIENT_MIN_OPTIONS_SIZE);
360 err = dhcp_option_append(opt, optlen,
361 DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
370 static uint16_t client_checksum(void *buf, int len)
380 for (i = 0; i < len / 2 ; i++)
389 sum = (sum & 0xffff) + (sum >> 16);
394 static void client_append_ip_headers(DHCPPacket *packet, uint16_t len)
396 packet->ip.version = IPVERSION;
397 packet->ip.ihl = DHCP_IP_SIZE / 4;
398 packet->ip.tot_len = htobe16(len);
400 packet->ip.protocol = IPPROTO_UDP;
401 packet->ip.saddr = INADDR_ANY;
402 packet->ip.daddr = INADDR_BROADCAST;
404 packet->udp.source = htobe16(DHCP_PORT_CLIENT);
405 packet->udp.dest = htobe16(DHCP_PORT_SERVER);
406 packet->udp.len = htobe16(len - DHCP_IP_SIZE);
408 packet->ip.check = packet->udp.len;
409 packet->udp.check = client_checksum(&packet->ip.ttl, len - 8);
411 packet->ip.ttl = IPDEFTTL;
412 packet->ip.check = 0;
413 packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE);
416 static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
419 _cleanup_free_ DHCPPacket *discover;
423 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
424 len = sizeof(DHCPPacket) + optlen;
426 discover = malloc0(len);
431 err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
432 secs, &opt, &optlen);
436 if (client->last_addr != INADDR_ANY) {
437 err = dhcp_option_append(&opt, &optlen,
438 DHCP_OPTION_REQUESTED_IP_ADDRESS,
439 4, &client->last_addr);
444 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
448 client_append_ip_headers(discover, len);
450 err = dhcp_network_send_raw_socket(client->fd, &client->link,
456 static int client_send_request(sd_dhcp_client *client, uint16_t secs)
458 _cleanup_free_ DHCPPacket *request;
463 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
464 len = DHCP_MESSAGE_SIZE + optlen;
466 request = malloc0(len);
470 err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs,
475 if (client->state == DHCP_STATE_REQUESTING) {
476 err = dhcp_option_append(&opt, &optlen,
477 DHCP_OPTION_REQUESTED_IP_ADDRESS,
478 4, &client->lease->address);
482 err = dhcp_option_append(&opt, &optlen,
483 DHCP_OPTION_SERVER_IDENTIFIER,
484 4, &client->lease->server_address);
489 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
493 client_append_ip_headers(request, len);
495 err = dhcp_network_send_raw_socket(client->fd, &client->link,
501 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
504 sd_dhcp_client *client = userdata;
509 secs = (usec - client->start_time) / USEC_PER_SEC;
511 if (client->attempt < 64)
512 client->attempt *= 2;
514 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC +
515 (random_u() & 0x1fffff);
517 err = sd_event_add_monotonic(client->event, next_timeout,
519 client_timeout_resend, client,
520 &client->timeout_resend);
524 switch (client->state) {
525 case DHCP_STATE_INIT:
526 err = client_send_discover(client, secs);
528 client->state = DHCP_STATE_SELECTING;
531 if (client->attempt >= 64)
537 case DHCP_STATE_SELECTING:
538 err = client_send_discover(client, secs);
539 if (err < 0 && client->attempt >= 64)
544 case DHCP_STATE_REQUESTING:
545 err = client_send_request(client, secs);
546 if (err < 0 && client->attempt >= 64)
549 client->request_sent = usec;
553 case DHCP_STATE_INIT_REBOOT:
554 case DHCP_STATE_REBOOTING:
555 case DHCP_STATE_BOUND:
556 case DHCP_STATE_RENEWING:
557 case DHCP_STATE_REBINDING:
565 client_stop(client, err);
567 /* Errors were dealt with when stopping the client, don't spill
568 errors into the event loop handler */
572 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
575 sd_dhcp_client *client = userdata;
577 client_stop(client, DHCP_EVENT_EXPIRED);
582 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata)
587 static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata)
592 static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option,
595 DHCPLease *lease = user_data;
600 case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
602 memcpy(&val, option, 4);
603 lease->lifetime = be32toh(val);
608 case DHCP_OPTION_SERVER_IDENTIFIER:
610 memcpy(&lease->server_address, option, 4);
614 case DHCP_OPTION_SUBNET_MASK:
616 memcpy(&lease->subnet_mask, option, 4);
620 case DHCP_OPTION_ROUTER:
622 memcpy(&lease->router, option, 4);
626 case DHCP_OPTION_RENEWAL_T1_TIME:
628 memcpy(&val, option, 4);
629 lease->t1 = be32toh(val);
634 case DHCP_OPTION_REBINDING_T2_TIME:
636 memcpy(&val, option, 4);
637 lease->t2 = be32toh(val);
646 static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
651 if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
654 hdrlen = message->ip.ihl * 4;
655 if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip,
659 message->ip.check = message->udp.len;
662 if (hdrlen + be16toh(message->udp.len) > len ||
663 client_checksum(&message->ip.ttl, be16toh(message->udp.len) + 12))
666 if (be16toh(message->udp.source) != DHCP_PORT_SERVER ||
667 be16toh(message->udp.dest) != DHCP_PORT_CLIENT)
670 if (message->dhcp.op != BOOTREPLY)
673 if (be32toh(message->dhcp.xid) != client->xid)
676 if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
683 static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
689 err = client_verify_headers(client, offer, len);
693 lease = new0(DHCPLease, 1);
697 len = len - DHCP_IP_UDP_SIZE;
698 if (dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
699 lease) != DHCP_OFFER)
702 lease->address = offer->dhcp.yiaddr;
704 if (lease->address == INADDR_ANY ||
705 lease->server_address == INADDR_ANY ||
706 lease->subnet_mask == INADDR_ANY ||
707 lease->lifetime == 0)
710 client->lease = lease;
720 static int client_receive_ack(sd_dhcp_client *client, DHCPPacket *offer,
726 r = client_verify_headers(client, offer, len);
730 lease = new0(DHCPLease, 1);
734 len = len - DHCP_IP_UDP_SIZE;
735 r = dhcp_option_parse(&offer->dhcp, len, client_parse_offer, lease);
738 r = DHCP_EVENT_NO_LEASE;
747 lease->address = offer->dhcp.yiaddr;
749 if (lease->address == INADDR_ANY ||
750 lease->server_address == INADDR_ANY ||
751 lease->subnet_mask == INADDR_ANY || lease->lifetime == 0) {
756 r = DHCP_EVENT_IP_ACQUIRE;
758 if (client->lease->address != lease->address ||
759 client->lease->subnet_mask != lease->subnet_mask ||
760 client->lease->router != lease->router) {
761 r = DHCP_EVENT_IP_CHANGE;
767 client->lease = lease;
777 static uint64_t client_compute_timeout(uint64_t request_sent,
780 return request_sent + (lifetime - 3) * USEC_PER_SEC +
781 + (random_u() & 0x1fffff);
784 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec)
787 uint64_t next_timeout;
789 if (client->lease->lifetime < 10)
792 if (!client->lease->t1)
793 client->lease->t1 = client->lease->lifetime / 2;
795 next_timeout = client_compute_timeout(client->request_sent,
797 if (next_timeout < usec)
800 err = sd_event_add_monotonic(client->event, next_timeout,
802 client_timeout_t1, client,
803 &client->timeout_t1);
807 if (!client->lease->t2)
808 client->lease->t2 = client->lease->lifetime * 7 / 8;
810 if (client->lease->t2 < client->lease->t1)
813 if (client->lease->lifetime < client->lease->t2)
816 next_timeout = client_compute_timeout(client->request_sent,
818 if (next_timeout < usec)
821 err = sd_event_add_monotonic(client->event, next_timeout,
823 client_timeout_t2, client,
824 &client->timeout_t2);
828 next_timeout = client_compute_timeout(client->request_sent,
829 client->lease->lifetime);
830 if (next_timeout < usec)
833 err = sd_event_add_monotonic(client->event, next_timeout,
835 client_timeout_expire, client,
836 &client->timeout_expire);
843 static int client_receive_raw_message(sd_event_source *s, int fd,
844 uint32_t revents, void *userdata)
846 sd_dhcp_client *client = userdata;
847 uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
848 int buflen = sizeof(buf);
853 len = read(fd, &buf, buflen);
857 r = sd_event_get_now_monotonic(client->event, &time_now);
861 message = (DHCPPacket *)&buf;
863 switch (client->state) {
864 case DHCP_STATE_SELECTING:
866 if (client_receive_offer(client, message, len) >= 0) {
868 client->timeout_resend =
869 sd_event_source_unref(client->timeout_resend);
871 client->state = DHCP_STATE_REQUESTING;
874 r = sd_event_add_monotonic(client->event, time_now, 0,
875 client_timeout_resend,
877 &client->timeout_resend);
884 case DHCP_STATE_REQUESTING:
886 r = client_receive_ack(client, message, len);
887 if (r == DHCP_EVENT_NO_LEASE)
891 client->timeout_resend =
892 sd_event_source_unref(client->timeout_resend);
894 client->state = DHCP_STATE_BOUND;
897 client->last_addr = client->lease->address;
899 r = client_set_lease_timeouts(client, time_now);
903 client_notify(client, DHCP_EVENT_IP_ACQUIRE);
905 client->receive_message =
906 sd_event_source_unref(client->receive_message);
915 case DHCP_STATE_INIT:
916 case DHCP_STATE_INIT_REBOOT:
917 case DHCP_STATE_REBOOTING:
918 case DHCP_STATE_BOUND:
919 case DHCP_STATE_RENEWING:
920 case DHCP_STATE_REBINDING:
926 if (r < 0 || r == DHCP_EVENT_NO_LEASE)
927 return client_stop(client, r);
932 int sd_dhcp_client_start(sd_dhcp_client *client)
936 assert_return(client, -EINVAL);
937 assert_return(client->index >= 0, -EINVAL);
938 assert_return(client->state == DHCP_STATE_INIT ||
939 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
941 client->xid = random_u();
943 client->fd = dhcp_network_bind_raw_socket(client->index,
946 if (client->fd < 0) {
951 err = sd_event_add_io(client->event, client->fd, EPOLLIN,
952 client_receive_raw_message, client,
953 &client->receive_message);
957 client->start_time = now(CLOCK_MONOTONIC);
958 err = sd_event_add_monotonic(client->event, client->start_time, 0,
959 client_timeout_resend, client,
960 &client->timeout_resend);
967 client_stop(client, err);
972 int sd_dhcp_client_stop(sd_dhcp_client *client)
974 return client_stop(client, DHCP_EVENT_STOP);
977 sd_dhcp_client *sd_dhcp_client_free(sd_dhcp_client *client)
979 assert_return(client, NULL);
981 sd_dhcp_client_stop(client);
983 sd_event_unref(client->event);
984 free(client->req_opts);
990 sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
992 sd_dhcp_client *client;
994 assert_return(event, NULL);
996 client = new0(sd_dhcp_client, 1);
1000 client->event = sd_event_ref(event);
1001 client->state = DHCP_STATE_INIT;
1004 client->attempt = 1;
1006 client->req_opts_size = ELEMENTSOF(default_req_opts);
1008 client->req_opts = memdup(default_req_opts, client->req_opts_size);
1009 if (!client->req_opts) {