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-internal.h"
32 #include "sd-dhcp-client.h"
34 #define DHCP_CLIENT_MIN_OPTIONS_SIZE 312
41 be32_t server_address;
46 typedef struct DHCPLease DHCPLease;
48 struct sd_dhcp_client {
51 sd_event_source *timeout_resend;
54 union sockaddr_union link;
55 sd_event_source *receive_message;
57 size_t req_opts_allocated;
60 struct ether_addr mac_addr;
65 sd_event_source *timeout_t1;
66 sd_event_source *timeout_t2;
67 sd_event_source *timeout_expire;
68 sd_dhcp_client_cb_t cb;
73 static const uint8_t default_req_opts[] = {
74 DHCP_OPTION_SUBNET_MASK,
76 DHCP_OPTION_HOST_NAME,
77 DHCP_OPTION_DOMAIN_NAME,
78 DHCP_OPTION_DOMAIN_NAME_SERVER,
79 DHCP_OPTION_NTP_SERVER,
82 static int client_receive_message(sd_event_source *s, int fd,
83 uint32_t revents, void *userdata);
85 int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
88 assert_return(client, -EINVAL);
91 client->userdata = userdata;
96 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option)
100 assert_return(client, -EINVAL);
101 assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
104 case DHCP_OPTION_PAD:
105 case DHCP_OPTION_OVERLOAD:
106 case DHCP_OPTION_MESSAGE_TYPE:
107 case DHCP_OPTION_PARAMETER_REQUEST_LIST:
108 case DHCP_OPTION_END:
115 for (i = 0; i < client->req_opts_size; i++)
116 if (client->req_opts[i] == option)
119 if (!GREEDY_REALLOC(client->req_opts, client->req_opts_allocated,
120 client->req_opts_size + 1))
123 client->req_opts[client->req_opts_size++] = option;
128 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
129 const struct in_addr *last_addr)
131 assert_return(client, -EINVAL);
132 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
135 client->last_addr = last_addr->s_addr;
137 client->last_addr = INADDR_ANY;
142 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index)
144 assert_return(client, -EINVAL);
145 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
146 assert_return(interface_index >= -1, -EINVAL);
148 client->index = interface_index;
153 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
154 const struct ether_addr *addr)
156 assert_return(client, -EINVAL);
157 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
159 memcpy(&client->mac_addr, addr, ETH_ALEN);
164 int sd_dhcp_client_get_address(sd_dhcp_client *client, struct in_addr *addr)
166 assert_return(client, -EINVAL);
167 assert_return(addr, -EINVAL);
169 switch (client->state) {
170 case DHCP_STATE_INIT:
171 case DHCP_STATE_SELECTING:
172 case DHCP_STATE_INIT_REBOOT:
173 case DHCP_STATE_REBOOTING:
174 case DHCP_STATE_REQUESTING:
175 return -EADDRNOTAVAIL;
177 case DHCP_STATE_BOUND:
178 case DHCP_STATE_RENEWING:
179 case DHCP_STATE_REBINDING:
180 addr->s_addr = client->lease->address;
188 int sd_dhcp_client_get_netmask(sd_dhcp_client *client, struct in_addr *addr)
190 assert_return(client, -EINVAL);
191 assert_return(addr, -EINVAL);
193 switch (client->state) {
194 case DHCP_STATE_INIT:
195 case DHCP_STATE_SELECTING:
196 case DHCP_STATE_INIT_REBOOT:
197 case DHCP_STATE_REBOOTING:
198 case DHCP_STATE_REQUESTING:
199 return -EADDRNOTAVAIL;
201 case DHCP_STATE_BOUND:
202 case DHCP_STATE_RENEWING:
203 case DHCP_STATE_REBINDING:
204 addr->s_addr = client->lease->subnet_mask;
212 int sd_dhcp_client_prefixlen(const struct in_addr *addr)
217 assert_return(addr, -EADDRNOTAVAIL);
219 mask = be32toh(addr->s_addr);
228 int sd_dhcp_client_get_router(sd_dhcp_client *client, struct in_addr *addr)
230 assert_return(client, -EINVAL);
231 assert_return(addr, -EINVAL);
233 switch (client->state) {
234 case DHCP_STATE_INIT:
235 case DHCP_STATE_SELECTING:
236 case DHCP_STATE_INIT_REBOOT:
237 case DHCP_STATE_REBOOTING:
238 case DHCP_STATE_REQUESTING:
239 return -EADDRNOTAVAIL;
241 case DHCP_STATE_BOUND:
242 case DHCP_STATE_RENEWING:
243 case DHCP_STATE_REBINDING:
244 addr->s_addr = client->lease->router;
252 static int client_notify(sd_dhcp_client *client, int event)
255 client->cb(client, event, client->userdata);
260 static int client_stop(sd_dhcp_client *client, int error)
262 assert_return(client, -EINVAL);
263 assert_return(client->state != DHCP_STATE_INIT &&
264 client->state != DHCP_STATE_INIT_REBOOT, -EALREADY);
266 client->receive_message =
267 sd_event_source_unref(client->receive_message);
273 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
275 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
276 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
277 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
281 client_notify(client, error);
283 switch (client->state) {
285 case DHCP_STATE_INIT:
286 case DHCP_STATE_SELECTING:
287 case DHCP_STATE_REQUESTING:
288 case DHCP_STATE_BOUND:
290 client->start_time = 0;
291 client->state = DHCP_STATE_INIT;
294 case DHCP_STATE_INIT_REBOOT:
295 case DHCP_STATE_REBOOTING:
296 case DHCP_STATE_RENEWING:
297 case DHCP_STATE_REBINDING:
304 client->lease = NULL;
310 static int client_packet_init(sd_dhcp_client *client, uint8_t type,
311 DHCPMessage *message, uint16_t secs,
312 uint8_t **opt, size_t *optlen)
317 *opt = (uint8_t *)(message + 1);
323 message->op = BOOTREQUEST;
325 message->hlen = ETHER_ADDR_LEN;
326 message->xid = htobe32(client->xid);
328 /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
329 refuse to issue an DHCP lease if 'secs' is set to zero */
330 message->secs = htobe16(secs);
332 if (client->state == DHCP_STATE_RENEWING ||
333 client->state == DHCP_STATE_REBINDING)
334 message->ciaddr = client->lease->address;
336 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
344 err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
349 /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
350 Identifier option is not set */
351 err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
352 ETH_ALEN, &client->mac_addr);
356 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
357 err = dhcp_option_append(opt, optlen,
358 DHCP_OPTION_PARAMETER_REQUEST_LIST,
359 client->req_opts_size,
364 /* Some DHCP servers will send bigger DHCP packets than the
365 defined default size unless the Maximum Messge Size option
366 is explicitely set */
367 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
368 DHCP_CLIENT_MIN_OPTIONS_SIZE);
369 err = dhcp_option_append(opt, optlen,
370 DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
379 static uint16_t client_checksum(void *buf, int len)
389 for (i = 0; i < len / 2 ; i++)
398 sum = (sum & 0xffff) + (sum >> 16);
403 static void client_append_ip_headers(DHCPPacket *packet, uint16_t len)
405 packet->ip.version = IPVERSION;
406 packet->ip.ihl = DHCP_IP_SIZE / 4;
407 packet->ip.tot_len = htobe16(len);
409 packet->ip.protocol = IPPROTO_UDP;
410 packet->ip.saddr = INADDR_ANY;
411 packet->ip.daddr = INADDR_BROADCAST;
413 packet->udp.source = htobe16(DHCP_PORT_CLIENT);
414 packet->udp.dest = htobe16(DHCP_PORT_SERVER);
415 packet->udp.len = htobe16(len - DHCP_IP_SIZE);
417 packet->ip.check = packet->udp.len;
418 packet->udp.check = client_checksum(&packet->ip.ttl, len - 8);
420 packet->ip.ttl = IPDEFTTL;
421 packet->ip.check = 0;
422 packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE);
425 static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
428 _cleanup_free_ DHCPPacket *discover;
432 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
433 len = sizeof(DHCPPacket) + optlen;
435 discover = malloc0(len);
440 err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
441 secs, &opt, &optlen);
445 if (client->last_addr != INADDR_ANY) {
446 err = dhcp_option_append(&opt, &optlen,
447 DHCP_OPTION_REQUESTED_IP_ADDRESS,
448 4, &client->last_addr);
453 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
457 client_append_ip_headers(discover, len);
459 err = dhcp_network_send_raw_socket(client->fd, &client->link,
465 static int client_send_request(sd_dhcp_client *client, uint16_t secs)
467 _cleanup_free_ DHCPPacket *request;
472 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
473 len = DHCP_MESSAGE_SIZE + optlen;
475 request = malloc0(len);
479 err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs,
484 if (client->state == DHCP_STATE_REQUESTING) {
485 err = dhcp_option_append(&opt, &optlen,
486 DHCP_OPTION_REQUESTED_IP_ADDRESS,
487 4, &client->lease->address);
491 err = dhcp_option_append(&opt, &optlen,
492 DHCP_OPTION_SERVER_IDENTIFIER,
493 4, &client->lease->server_address);
498 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
502 if (client->state == DHCP_STATE_RENEWING) {
503 err = dhcp_network_send_udp_socket(client->fd,
504 client->lease->server_address,
506 len - DHCP_IP_UDP_SIZE);
508 client_append_ip_headers(request, len);
510 err = dhcp_network_send_raw_socket(client->fd, &client->link,
517 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
520 sd_dhcp_client *client = userdata;
521 usec_t next_timeout = 0;
526 switch (client->state) {
527 case DHCP_STATE_RENEWING:
529 time_left = (client->lease->t2 - client->lease->t1)/2;
533 next_timeout = usec + time_left * USEC_PER_SEC;
537 case DHCP_STATE_REBINDING:
539 time_left = (client->lease->lifetime - client->lease->t2)/2;
543 next_timeout = usec + time_left * USEC_PER_SEC;
546 case DHCP_STATE_INIT:
547 case DHCP_STATE_INIT_REBOOT:
548 case DHCP_STATE_REBOOTING:
549 case DHCP_STATE_SELECTING:
550 case DHCP_STATE_REQUESTING:
551 case DHCP_STATE_BOUND:
553 if (client->attempt < 64)
554 client->attempt *= 2;
556 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
561 next_timeout += (random_u32() & 0x1fffff);
563 err = sd_event_add_monotonic(client->event, next_timeout,
565 client_timeout_resend, client,
566 &client->timeout_resend);
570 secs = (usec - client->start_time) / USEC_PER_SEC;
572 switch (client->state) {
573 case DHCP_STATE_INIT:
574 err = client_send_discover(client, secs);
576 client->state = DHCP_STATE_SELECTING;
579 if (client->attempt >= 64)
585 case DHCP_STATE_SELECTING:
586 err = client_send_discover(client, secs);
587 if (err < 0 && client->attempt >= 64)
592 case DHCP_STATE_REQUESTING:
593 case DHCP_STATE_RENEWING:
594 case DHCP_STATE_REBINDING:
595 err = client_send_request(client, secs);
596 if (err < 0 && client->attempt >= 64)
599 client->request_sent = usec;
603 case DHCP_STATE_INIT_REBOOT:
604 case DHCP_STATE_REBOOTING:
605 case DHCP_STATE_BOUND:
613 client_stop(client, err);
615 /* Errors were dealt with when stopping the client, don't spill
616 errors into the event loop handler */
620 static int client_initialize_events(sd_dhcp_client *client, usec_t usec)
624 r = sd_event_add_io(client->event, client->fd, EPOLLIN,
625 client_receive_message, client,
626 &client->receive_message);
630 r = sd_event_add_monotonic(client->event, usec, 0,
631 client_timeout_resend, client,
632 &client->timeout_resend);
636 client_stop(client, r);
642 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
645 sd_dhcp_client *client = userdata;
647 client_stop(client, DHCP_EVENT_EXPIRED);
652 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata)
654 sd_dhcp_client *client = userdata;
657 if (client->fd >= 0) {
658 client->receive_message =
659 sd_event_source_unref(client->receive_message);
664 client->state = DHCP_STATE_REBINDING;
667 r = dhcp_network_bind_raw_socket(client->index, &client->link);
669 client_stop(client, r);
675 return client_initialize_events(client, usec);
678 static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata)
680 sd_dhcp_client *client = userdata;
683 client->state = DHCP_STATE_RENEWING;
686 r = dhcp_network_bind_udp_socket(client->index,
687 client->lease->address);
689 client_stop(client, r);
695 return client_initialize_events(client, usec);
698 static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option,
701 DHCPLease *lease = user_data;
706 case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
708 memcpy(&val, option, 4);
709 lease->lifetime = be32toh(val);
714 case DHCP_OPTION_SERVER_IDENTIFIER:
716 memcpy(&lease->server_address, option, 4);
720 case DHCP_OPTION_SUBNET_MASK:
722 memcpy(&lease->subnet_mask, option, 4);
726 case DHCP_OPTION_ROUTER:
728 memcpy(&lease->router, option, 4);
732 case DHCP_OPTION_RENEWAL_T1_TIME:
734 memcpy(&val, option, 4);
735 lease->t1 = be32toh(val);
740 case DHCP_OPTION_REBINDING_T2_TIME:
742 memcpy(&val, option, 4);
743 lease->t2 = be32toh(val);
752 static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
757 if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
760 hdrlen = message->ip.ihl * 4;
761 if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip,
765 message->ip.check = message->udp.len;
768 if (hdrlen + be16toh(message->udp.len) > len ||
769 client_checksum(&message->ip.ttl, be16toh(message->udp.len) + 12))
772 if (be16toh(message->udp.source) != DHCP_PORT_SERVER ||
773 be16toh(message->udp.dest) != DHCP_PORT_CLIENT)
776 if (message->dhcp.op != BOOTREPLY)
779 if (be32toh(message->dhcp.xid) != client->xid)
782 if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
789 static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
795 err = client_verify_headers(client, offer, len);
799 lease = new0(DHCPLease, 1);
803 len = len - DHCP_IP_UDP_SIZE;
804 if (dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
805 lease) != DHCP_OFFER)
808 lease->address = offer->dhcp.yiaddr;
810 if (lease->address == INADDR_ANY ||
811 lease->server_address == INADDR_ANY ||
812 lease->subnet_mask == INADDR_ANY ||
813 lease->lifetime == 0)
816 client->lease = lease;
826 static int client_receive_ack(sd_dhcp_client *client, const uint8_t *buf,
834 if (client->state == DHCP_STATE_RENEWING) {
835 dhcp = (DHCPMessage *)buf;
837 ack = (DHCPPacket *)buf;
839 r = client_verify_headers(client, ack, len);
844 len -= DHCP_IP_UDP_SIZE;
847 lease = new0(DHCPLease, 1);
851 r = dhcp_option_parse(dhcp, len, client_parse_offer, lease);
854 r = DHCP_EVENT_NO_LEASE;
863 lease->address = dhcp->yiaddr;
865 if (lease->address == INADDR_ANY ||
866 lease->server_address == INADDR_ANY ||
867 lease->subnet_mask == INADDR_ANY || lease->lifetime == 0) {
872 r = DHCP_EVENT_IP_ACQUIRE;
874 if (client->lease->address != lease->address ||
875 client->lease->subnet_mask != lease->subnet_mask ||
876 client->lease->router != lease->router) {
877 r = DHCP_EVENT_IP_CHANGE;
883 client->lease = lease;
893 static uint64_t client_compute_timeout(uint64_t request_sent,
896 return request_sent + (lifetime - 3) * USEC_PER_SEC +
897 + (random_u32() & 0x1fffff);
900 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec)
903 uint64_t next_timeout;
905 if (client->lease->lifetime < 10)
908 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
909 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
910 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
912 if (!client->lease->t1)
913 client->lease->t1 = client->lease->lifetime / 2;
915 next_timeout = client_compute_timeout(client->request_sent,
917 if (next_timeout < usec)
920 err = sd_event_add_monotonic(client->event, next_timeout,
922 client_timeout_t1, client,
923 &client->timeout_t1);
927 if (!client->lease->t2)
928 client->lease->t2 = client->lease->lifetime * 7 / 8;
930 if (client->lease->t2 < client->lease->t1)
933 if (client->lease->lifetime < client->lease->t2)
936 next_timeout = client_compute_timeout(client->request_sent,
938 if (next_timeout < usec)
941 err = sd_event_add_monotonic(client->event, next_timeout,
943 client_timeout_t2, client,
944 &client->timeout_t2);
948 next_timeout = client_compute_timeout(client->request_sent,
949 client->lease->lifetime);
950 if (next_timeout < usec)
953 err = sd_event_add_monotonic(client->event, next_timeout,
955 client_timeout_expire, client,
956 &client->timeout_expire);
963 static int client_receive_message(sd_event_source *s, int fd,
964 uint32_t revents, void *userdata)
966 sd_dhcp_client *client = userdata;
967 uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
968 int buflen = sizeof(buf);
969 int len, r = 0, notify_event = 0;
973 len = read(fd, &buf, buflen);
977 r = sd_event_get_now_monotonic(client->event, &time_now);
981 switch (client->state) {
982 case DHCP_STATE_SELECTING:
984 message = (DHCPPacket *)&buf;
986 if (client_receive_offer(client, message, len) >= 0) {
988 client->timeout_resend =
989 sd_event_source_unref(client->timeout_resend);
991 client->state = DHCP_STATE_REQUESTING;
994 r = sd_event_add_monotonic(client->event, time_now, 0,
995 client_timeout_resend,
997 &client->timeout_resend);
1004 case DHCP_STATE_REQUESTING:
1005 case DHCP_STATE_RENEWING:
1006 case DHCP_STATE_REBINDING:
1008 r = client_receive_ack(client, buf, len);
1010 if (r == DHCP_EVENT_NO_LEASE)
1014 client->timeout_resend =
1015 sd_event_source_unref(client->timeout_resend);
1017 if (client->state == DHCP_STATE_REQUESTING)
1018 notify_event = DHCP_EVENT_IP_ACQUIRE;
1019 else if (r != DHCP_EVENT_IP_ACQUIRE)
1022 client->state = DHCP_STATE_BOUND;
1023 client->attempt = 1;
1025 client->last_addr = client->lease->address;
1027 r = client_set_lease_timeouts(client, time_now);
1032 client_notify(client, notify_event);
1034 client->receive_message =
1035 sd_event_source_unref(client->receive_message);
1044 case DHCP_STATE_INIT:
1045 case DHCP_STATE_INIT_REBOOT:
1046 case DHCP_STATE_REBOOTING:
1047 case DHCP_STATE_BOUND:
1053 if (r < 0 || r == DHCP_EVENT_NO_LEASE)
1054 return client_stop(client, r);
1059 int sd_dhcp_client_start(sd_dhcp_client *client)
1063 assert_return(client, -EINVAL);
1064 assert_return(client->index > 0, -EINVAL);
1065 assert_return(client->state == DHCP_STATE_INIT ||
1066 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
1068 client->xid = random_u32();
1070 r = dhcp_network_bind_raw_socket(client->index, &client->link);
1073 client_stop(client, r);
1078 client->start_time = now(CLOCK_MONOTONIC);
1080 return client_initialize_events(client, client->start_time);
1083 int sd_dhcp_client_stop(sd_dhcp_client *client)
1085 return client_stop(client, DHCP_EVENT_STOP);
1088 sd_dhcp_client *sd_dhcp_client_free(sd_dhcp_client *client)
1090 assert_return(client, NULL);
1092 sd_dhcp_client_stop(client);
1094 sd_event_unref(client->event);
1095 free(client->req_opts);
1101 sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
1103 sd_dhcp_client *client;
1105 assert_return(event, NULL);
1107 client = new0(sd_dhcp_client, 1);
1111 client->event = sd_event_ref(event);
1112 client->state = DHCP_STATE_INIT;
1115 client->attempt = 1;
1117 client->req_opts_size = ELEMENTSOF(default_req_opts);
1119 client->req_opts = memdup(default_req_opts, client->req_opts_size);
1120 if (!client->req_opts) {