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;
59 struct ether_addr mac_addr;
64 sd_event_source *timeout_t1;
65 sd_event_source *timeout_t2;
66 sd_event_source *timeout_expire;
67 sd_dhcp_client_cb_t cb;
72 static const uint8_t default_req_opts[] = {
73 DHCP_OPTION_SUBNET_MASK,
75 DHCP_OPTION_HOST_NAME,
76 DHCP_OPTION_DOMAIN_NAME,
77 DHCP_OPTION_DOMAIN_NAME_SERVER,
78 DHCP_OPTION_NTP_SERVER,
81 static int client_receive_message(sd_event_source *s, int fd,
82 uint32_t revents, void *userdata);
84 int sd_dhcp_client_set_callback(sd_dhcp_client *client, sd_dhcp_client_cb_t cb,
87 assert_return(client, -EINVAL);
90 client->userdata = userdata;
95 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option)
99 assert_return(client, -EINVAL);
100 assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
103 case DHCP_OPTION_PAD:
104 case DHCP_OPTION_OVERLOAD:
105 case DHCP_OPTION_MESSAGE_TYPE:
106 case DHCP_OPTION_PARAMETER_REQUEST_LIST:
107 case DHCP_OPTION_END:
114 for (i = 0; i < client->req_opts_size; i++)
115 if (client->req_opts[i] == option)
118 if (!GREEDY_REALLOC(client->req_opts, client->req_opts_size,
119 client->req_opts_size + 1))
122 client->req_opts[client->req_opts_size - 1] = option;
127 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
128 const struct in_addr *last_addr)
130 assert_return(client, -EINVAL);
131 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
134 client->last_addr = last_addr->s_addr;
136 client->last_addr = INADDR_ANY;
141 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index)
143 assert_return(client, -EINVAL);
144 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
145 assert_return(interface_index >= -1, -EINVAL);
147 client->index = interface_index;
152 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
153 const struct ether_addr *addr)
155 assert_return(client, -EINVAL);
156 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
158 memcpy(&client->mac_addr, addr, ETH_ALEN);
163 int sd_dhcp_client_get_address(sd_dhcp_client *client, struct in_addr *addr)
165 assert_return(client, -EINVAL);
166 assert_return(addr, -EINVAL);
168 switch (client->state) {
169 case DHCP_STATE_INIT:
170 case DHCP_STATE_SELECTING:
171 case DHCP_STATE_INIT_REBOOT:
172 case DHCP_STATE_REBOOTING:
173 case DHCP_STATE_REQUESTING:
174 return -EADDRNOTAVAIL;
176 case DHCP_STATE_BOUND:
177 case DHCP_STATE_RENEWING:
178 case DHCP_STATE_REBINDING:
179 addr->s_addr = client->lease->address;
187 int sd_dhcp_client_get_netmask(sd_dhcp_client *client, struct in_addr *addr)
189 assert_return(client, -EINVAL);
190 assert_return(addr, -EINVAL);
192 switch (client->state) {
193 case DHCP_STATE_INIT:
194 case DHCP_STATE_SELECTING:
195 case DHCP_STATE_INIT_REBOOT:
196 case DHCP_STATE_REBOOTING:
197 case DHCP_STATE_REQUESTING:
198 return -EADDRNOTAVAIL;
200 case DHCP_STATE_BOUND:
201 case DHCP_STATE_RENEWING:
202 case DHCP_STATE_REBINDING:
203 addr->s_addr = client->lease->subnet_mask;
211 int sd_dhcp_client_prefixlen(const struct in_addr *addr)
216 assert_return(addr, -EADDRNOTAVAIL);
218 mask = be32toh(addr->s_addr);
227 int sd_dhcp_client_get_router(sd_dhcp_client *client, struct in_addr *addr)
229 assert_return(client, -EINVAL);
230 assert_return(addr, -EINVAL);
232 switch (client->state) {
233 case DHCP_STATE_INIT:
234 case DHCP_STATE_SELECTING:
235 case DHCP_STATE_INIT_REBOOT:
236 case DHCP_STATE_REBOOTING:
237 case DHCP_STATE_REQUESTING:
238 return -EADDRNOTAVAIL;
240 case DHCP_STATE_BOUND:
241 case DHCP_STATE_RENEWING:
242 case DHCP_STATE_REBINDING:
243 addr->s_addr = client->lease->router;
251 static int client_notify(sd_dhcp_client *client, int event)
254 client->cb(client, event, client->userdata);
259 static int client_stop(sd_dhcp_client *client, int error)
261 assert_return(client, -EINVAL);
262 assert_return(client->state != DHCP_STATE_INIT &&
263 client->state != DHCP_STATE_INIT_REBOOT, -EALREADY);
265 client->receive_message =
266 sd_event_source_unref(client->receive_message);
272 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
274 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
275 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
276 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
280 client_notify(client, error);
282 switch (client->state) {
284 case DHCP_STATE_INIT:
285 case DHCP_STATE_SELECTING:
286 case DHCP_STATE_REQUESTING:
287 case DHCP_STATE_BOUND:
289 client->start_time = 0;
290 client->state = DHCP_STATE_INIT;
293 case DHCP_STATE_INIT_REBOOT:
294 case DHCP_STATE_REBOOTING:
295 case DHCP_STATE_RENEWING:
296 case DHCP_STATE_REBINDING:
303 client->lease = NULL;
309 static int client_packet_init(sd_dhcp_client *client, uint8_t type,
310 DHCPMessage *message, uint16_t secs,
311 uint8_t **opt, size_t *optlen)
316 *opt = (uint8_t *)(message + 1);
322 message->op = BOOTREQUEST;
324 message->hlen = ETHER_ADDR_LEN;
325 message->xid = htobe32(client->xid);
327 /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
328 refuse to issue an DHCP lease if 'secs' is set to zero */
329 message->secs = htobe16(secs);
331 if (client->state == DHCP_STATE_RENEWING)
332 message->ciaddr = client->lease->address;
334 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
342 err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
347 /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
348 Identifier option is not set */
349 err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
350 ETH_ALEN, &client->mac_addr);
354 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
355 err = dhcp_option_append(opt, optlen,
356 DHCP_OPTION_PARAMETER_REQUEST_LIST,
357 client->req_opts_size,
362 /* Some DHCP servers will send bigger DHCP packets than the
363 defined default size unless the Maximum Messge Size option
364 is explicitely set */
365 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
366 DHCP_CLIENT_MIN_OPTIONS_SIZE);
367 err = dhcp_option_append(opt, optlen,
368 DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
377 static uint16_t client_checksum(void *buf, int len)
387 for (i = 0; i < len / 2 ; i++)
396 sum = (sum & 0xffff) + (sum >> 16);
401 static void client_append_ip_headers(DHCPPacket *packet, uint16_t len)
403 packet->ip.version = IPVERSION;
404 packet->ip.ihl = DHCP_IP_SIZE / 4;
405 packet->ip.tot_len = htobe16(len);
407 packet->ip.protocol = IPPROTO_UDP;
408 packet->ip.saddr = INADDR_ANY;
409 packet->ip.daddr = INADDR_BROADCAST;
411 packet->udp.source = htobe16(DHCP_PORT_CLIENT);
412 packet->udp.dest = htobe16(DHCP_PORT_SERVER);
413 packet->udp.len = htobe16(len - DHCP_IP_SIZE);
415 packet->ip.check = packet->udp.len;
416 packet->udp.check = client_checksum(&packet->ip.ttl, len - 8);
418 packet->ip.ttl = IPDEFTTL;
419 packet->ip.check = 0;
420 packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE);
423 static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
426 _cleanup_free_ DHCPPacket *discover;
430 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
431 len = sizeof(DHCPPacket) + optlen;
433 discover = malloc0(len);
438 err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
439 secs, &opt, &optlen);
443 if (client->last_addr != INADDR_ANY) {
444 err = dhcp_option_append(&opt, &optlen,
445 DHCP_OPTION_REQUESTED_IP_ADDRESS,
446 4, &client->last_addr);
451 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
455 client_append_ip_headers(discover, len);
457 err = dhcp_network_send_raw_socket(client->fd, &client->link,
463 static int client_send_request(sd_dhcp_client *client, uint16_t secs)
465 _cleanup_free_ DHCPPacket *request;
470 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
471 len = DHCP_MESSAGE_SIZE + optlen;
473 request = malloc0(len);
477 err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs,
482 if (client->state == DHCP_STATE_REQUESTING) {
483 err = dhcp_option_append(&opt, &optlen,
484 DHCP_OPTION_REQUESTED_IP_ADDRESS,
485 4, &client->lease->address);
489 err = dhcp_option_append(&opt, &optlen,
490 DHCP_OPTION_SERVER_IDENTIFIER,
491 4, &client->lease->server_address);
496 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
500 if (client->state == DHCP_STATE_RENEWING) {
501 err = dhcp_network_send_udp_socket(client->fd,
502 client->lease->server_address,
504 len - DHCP_IP_UDP_SIZE);
506 client_append_ip_headers(request, len);
508 err = dhcp_network_send_raw_socket(client->fd, &client->link,
515 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
518 sd_dhcp_client *client = userdata;
519 usec_t next_timeout = 0;
524 switch (client->state) {
525 case DHCP_STATE_RENEWING:
527 time_left = (client->lease->t2 - client->lease->t1)/2;
531 next_timeout = usec + time_left * USEC_PER_SEC;
535 case DHCP_STATE_INIT:
536 case DHCP_STATE_INIT_REBOOT:
537 case DHCP_STATE_REBOOTING:
538 case DHCP_STATE_SELECTING:
539 case DHCP_STATE_REQUESTING:
540 case DHCP_STATE_BOUND:
541 case DHCP_STATE_REBINDING:
543 if (client->attempt < 64)
544 client->attempt *= 2;
546 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
551 next_timeout += (random_u() & 0x1fffff);
553 err = sd_event_add_monotonic(client->event, next_timeout,
555 client_timeout_resend, client,
556 &client->timeout_resend);
560 secs = (usec - client->start_time) / USEC_PER_SEC;
562 switch (client->state) {
563 case DHCP_STATE_INIT:
564 err = client_send_discover(client, secs);
566 client->state = DHCP_STATE_SELECTING;
569 if (client->attempt >= 64)
575 case DHCP_STATE_SELECTING:
576 err = client_send_discover(client, secs);
577 if (err < 0 && client->attempt >= 64)
582 case DHCP_STATE_REQUESTING:
583 case DHCP_STATE_RENEWING:
584 err = client_send_request(client, secs);
585 if (err < 0 && client->attempt >= 64)
588 client->request_sent = usec;
592 case DHCP_STATE_INIT_REBOOT:
593 case DHCP_STATE_REBOOTING:
594 case DHCP_STATE_BOUND:
595 case DHCP_STATE_REBINDING:
603 client_stop(client, err);
605 /* Errors were dealt with when stopping the client, don't spill
606 errors into the event loop handler */
610 static int client_initialize_events(sd_dhcp_client *client, usec_t usec)
614 r = sd_event_add_io(client->event, client->fd, EPOLLIN,
615 client_receive_message, client,
616 &client->receive_message);
620 r = sd_event_add_monotonic(client->event, usec, 0,
621 client_timeout_resend, client,
622 &client->timeout_resend);
626 client_stop(client, r);
632 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
635 sd_dhcp_client *client = userdata;
637 client_stop(client, DHCP_EVENT_EXPIRED);
642 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata)
647 static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata)
649 sd_dhcp_client *client = userdata;
652 client->state = DHCP_STATE_RENEWING;
655 r = dhcp_network_bind_udp_socket(client->index,
656 client->lease->address);
658 client_stop(client, r);
664 return client_initialize_events(client, usec);
667 static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option,
670 DHCPLease *lease = user_data;
675 case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
677 memcpy(&val, option, 4);
678 lease->lifetime = be32toh(val);
683 case DHCP_OPTION_SERVER_IDENTIFIER:
685 memcpy(&lease->server_address, option, 4);
689 case DHCP_OPTION_SUBNET_MASK:
691 memcpy(&lease->subnet_mask, option, 4);
695 case DHCP_OPTION_ROUTER:
697 memcpy(&lease->router, option, 4);
701 case DHCP_OPTION_RENEWAL_T1_TIME:
703 memcpy(&val, option, 4);
704 lease->t1 = be32toh(val);
709 case DHCP_OPTION_REBINDING_T2_TIME:
711 memcpy(&val, option, 4);
712 lease->t2 = be32toh(val);
721 static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
726 if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
729 hdrlen = message->ip.ihl * 4;
730 if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip,
734 message->ip.check = message->udp.len;
737 if (hdrlen + be16toh(message->udp.len) > len ||
738 client_checksum(&message->ip.ttl, be16toh(message->udp.len) + 12))
741 if (be16toh(message->udp.source) != DHCP_PORT_SERVER ||
742 be16toh(message->udp.dest) != DHCP_PORT_CLIENT)
745 if (message->dhcp.op != BOOTREPLY)
748 if (be32toh(message->dhcp.xid) != client->xid)
751 if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
758 static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
764 err = client_verify_headers(client, offer, len);
768 lease = new0(DHCPLease, 1);
772 len = len - DHCP_IP_UDP_SIZE;
773 if (dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
774 lease) != DHCP_OFFER)
777 lease->address = offer->dhcp.yiaddr;
779 if (lease->address == INADDR_ANY ||
780 lease->server_address == INADDR_ANY ||
781 lease->subnet_mask == INADDR_ANY ||
782 lease->lifetime == 0)
785 client->lease = lease;
795 static int client_receive_ack(sd_dhcp_client *client, const uint8_t *buf,
803 if (client->state == DHCP_STATE_RENEWING) {
804 dhcp = (DHCPMessage *)buf;
806 ack = (DHCPPacket *)buf;
808 r = client_verify_headers(client, ack, len);
813 len -= DHCP_IP_UDP_SIZE;
816 lease = new0(DHCPLease, 1);
820 r = dhcp_option_parse(dhcp, len, client_parse_offer, lease);
823 r = DHCP_EVENT_NO_LEASE;
832 lease->address = dhcp->yiaddr;
834 if (lease->address == INADDR_ANY ||
835 lease->server_address == INADDR_ANY ||
836 lease->subnet_mask == INADDR_ANY || lease->lifetime == 0) {
841 r = DHCP_EVENT_IP_ACQUIRE;
843 if (client->lease->address != lease->address ||
844 client->lease->subnet_mask != lease->subnet_mask ||
845 client->lease->router != lease->router) {
846 r = DHCP_EVENT_IP_CHANGE;
852 client->lease = lease;
862 static uint64_t client_compute_timeout(uint64_t request_sent,
865 return request_sent + (lifetime - 3) * USEC_PER_SEC +
866 + (random_u() & 0x1fffff);
869 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec)
872 uint64_t next_timeout;
874 if (client->lease->lifetime < 10)
877 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
878 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
879 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
881 if (!client->lease->t1)
882 client->lease->t1 = client->lease->lifetime / 2;
884 next_timeout = client_compute_timeout(client->request_sent,
886 if (next_timeout < usec)
889 err = sd_event_add_monotonic(client->event, next_timeout,
891 client_timeout_t1, client,
892 &client->timeout_t1);
896 if (!client->lease->t2)
897 client->lease->t2 = client->lease->lifetime * 7 / 8;
899 if (client->lease->t2 < client->lease->t1)
902 if (client->lease->lifetime < client->lease->t2)
905 next_timeout = client_compute_timeout(client->request_sent,
907 if (next_timeout < usec)
910 err = sd_event_add_monotonic(client->event, next_timeout,
912 client_timeout_t2, client,
913 &client->timeout_t2);
917 next_timeout = client_compute_timeout(client->request_sent,
918 client->lease->lifetime);
919 if (next_timeout < usec)
922 err = sd_event_add_monotonic(client->event, next_timeout,
924 client_timeout_expire, client,
925 &client->timeout_expire);
932 static int client_receive_message(sd_event_source *s, int fd,
933 uint32_t revents, void *userdata)
935 sd_dhcp_client *client = userdata;
936 uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
937 int buflen = sizeof(buf);
938 int len, r = 0, notify_event = 0;
942 len = read(fd, &buf, buflen);
946 r = sd_event_get_now_monotonic(client->event, &time_now);
950 switch (client->state) {
951 case DHCP_STATE_SELECTING:
953 message = (DHCPPacket *)&buf;
955 if (client_receive_offer(client, message, len) >= 0) {
957 client->timeout_resend =
958 sd_event_source_unref(client->timeout_resend);
960 client->state = DHCP_STATE_REQUESTING;
963 r = sd_event_add_monotonic(client->event, time_now, 0,
964 client_timeout_resend,
966 &client->timeout_resend);
973 case DHCP_STATE_REQUESTING:
974 case DHCP_STATE_RENEWING:
976 r = client_receive_ack(client, buf, len);
978 if (r == DHCP_EVENT_NO_LEASE)
982 client->timeout_resend =
983 sd_event_source_unref(client->timeout_resend);
985 if (client->state == DHCP_STATE_REQUESTING)
986 notify_event = DHCP_EVENT_IP_ACQUIRE;
987 else if (r != DHCP_EVENT_IP_ACQUIRE)
990 client->state = DHCP_STATE_BOUND;
993 client->last_addr = client->lease->address;
995 r = client_set_lease_timeouts(client, time_now);
1000 client_notify(client, notify_event);
1002 client->receive_message =
1003 sd_event_source_unref(client->receive_message);
1012 case DHCP_STATE_INIT:
1013 case DHCP_STATE_INIT_REBOOT:
1014 case DHCP_STATE_REBOOTING:
1015 case DHCP_STATE_BOUND:
1016 case DHCP_STATE_REBINDING:
1022 if (r < 0 || r == DHCP_EVENT_NO_LEASE)
1023 return client_stop(client, r);
1028 int sd_dhcp_client_start(sd_dhcp_client *client)
1032 assert_return(client, -EINVAL);
1033 assert_return(client->index >= 0, -EINVAL);
1034 assert_return(client->state == DHCP_STATE_INIT ||
1035 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
1037 client->xid = random_u();
1039 r = dhcp_network_bind_raw_socket(client->index, &client->link);
1042 client_stop(client, r);
1047 client->start_time = now(CLOCK_MONOTONIC);
1049 return client_initialize_events(client, client->start_time);
1052 int sd_dhcp_client_stop(sd_dhcp_client *client)
1054 return client_stop(client, DHCP_EVENT_STOP);
1057 sd_dhcp_client *sd_dhcp_client_free(sd_dhcp_client *client)
1059 assert_return(client, NULL);
1061 sd_dhcp_client_stop(client);
1063 sd_event_unref(client->event);
1064 free(client->req_opts);
1070 sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
1072 sd_dhcp_client *client;
1074 assert_return(event, NULL);
1076 client = new0(sd_dhcp_client, 1);
1080 client->event = sd_event_ref(event);
1081 client->state = DHCP_STATE_INIT;
1084 client->attempt = 1;
1086 client->req_opts_size = ELEMENTSOF(default_req_opts);
1088 client->req_opts = memdup(default_req_opts, client->req_opts_size);
1089 if (!client->req_opts) {