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);
264 client->receive_message =
265 sd_event_source_unref(client->receive_message);
271 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
273 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
274 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
275 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
279 client_notify(client, error);
281 switch (client->state) {
283 case DHCP_STATE_INIT:
284 case DHCP_STATE_SELECTING:
285 case DHCP_STATE_REQUESTING:
286 case DHCP_STATE_BOUND:
288 client->start_time = 0;
289 client->state = DHCP_STATE_INIT;
292 case DHCP_STATE_INIT_REBOOT:
293 case DHCP_STATE_REBOOTING:
294 case DHCP_STATE_RENEWING:
295 case DHCP_STATE_REBINDING:
302 client->lease = NULL;
308 static int client_packet_init(sd_dhcp_client *client, uint8_t type,
309 DHCPMessage *message, uint16_t secs,
310 uint8_t **opt, size_t *optlen)
315 *opt = (uint8_t *)(message + 1);
321 message->op = BOOTREQUEST;
323 message->hlen = ETHER_ADDR_LEN;
324 message->xid = htobe32(client->xid);
326 /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
327 refuse to issue an DHCP lease if 'secs' is set to zero */
328 message->secs = htobe16(secs);
330 if (client->state == DHCP_STATE_RENEWING ||
331 client->state == DHCP_STATE_REBINDING)
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_REBINDING:
537 time_left = (client->lease->lifetime - client->lease->t2)/2;
541 next_timeout = usec + time_left * USEC_PER_SEC;
544 case DHCP_STATE_INIT:
545 case DHCP_STATE_INIT_REBOOT:
546 case DHCP_STATE_REBOOTING:
547 case DHCP_STATE_SELECTING:
548 case DHCP_STATE_REQUESTING:
549 case DHCP_STATE_BOUND:
551 if (client->attempt < 64)
552 client->attempt *= 2;
554 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC;
559 next_timeout += (random_u32() & 0x1fffff);
561 err = sd_event_add_monotonic(client->event, next_timeout,
563 client_timeout_resend, client,
564 &client->timeout_resend);
568 secs = (usec - client->start_time) / USEC_PER_SEC;
570 switch (client->state) {
571 case DHCP_STATE_INIT:
572 err = client_send_discover(client, secs);
574 client->state = DHCP_STATE_SELECTING;
577 if (client->attempt >= 64)
583 case DHCP_STATE_SELECTING:
584 err = client_send_discover(client, secs);
585 if (err < 0 && client->attempt >= 64)
590 case DHCP_STATE_REQUESTING:
591 case DHCP_STATE_RENEWING:
592 case DHCP_STATE_REBINDING:
593 err = client_send_request(client, secs);
594 if (err < 0 && client->attempt >= 64)
597 client->request_sent = usec;
601 case DHCP_STATE_INIT_REBOOT:
602 case DHCP_STATE_REBOOTING:
603 case DHCP_STATE_BOUND:
611 client_stop(client, err);
613 /* Errors were dealt with when stopping the client, don't spill
614 errors into the event loop handler */
618 static int client_initialize_events(sd_dhcp_client *client, usec_t usec)
622 r = sd_event_add_io(client->event, client->fd, EPOLLIN,
623 client_receive_message, client,
624 &client->receive_message);
628 r = sd_event_add_monotonic(client->event, usec, 0,
629 client_timeout_resend, client,
630 &client->timeout_resend);
634 client_stop(client, r);
640 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
643 sd_dhcp_client *client = userdata;
645 client_stop(client, DHCP_EVENT_EXPIRED);
650 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata)
652 sd_dhcp_client *client = userdata;
655 if (client->fd >= 0) {
656 client->receive_message =
657 sd_event_source_unref(client->receive_message);
662 client->state = DHCP_STATE_REBINDING;
665 r = dhcp_network_bind_raw_socket(client->index, &client->link);
667 client_stop(client, r);
673 return client_initialize_events(client, usec);
676 static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata)
678 sd_dhcp_client *client = userdata;
681 client->state = DHCP_STATE_RENEWING;
684 r = dhcp_network_bind_udp_socket(client->index,
685 client->lease->address);
687 client_stop(client, r);
693 return client_initialize_events(client, usec);
696 static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option,
699 DHCPLease *lease = user_data;
704 case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
706 memcpy(&val, option, 4);
707 lease->lifetime = be32toh(val);
712 case DHCP_OPTION_SERVER_IDENTIFIER:
714 memcpy(&lease->server_address, option, 4);
718 case DHCP_OPTION_SUBNET_MASK:
720 memcpy(&lease->subnet_mask, option, 4);
724 case DHCP_OPTION_ROUTER:
726 memcpy(&lease->router, option, 4);
730 case DHCP_OPTION_RENEWAL_T1_TIME:
732 memcpy(&val, option, 4);
733 lease->t1 = be32toh(val);
738 case DHCP_OPTION_REBINDING_T2_TIME:
740 memcpy(&val, option, 4);
741 lease->t2 = be32toh(val);
750 static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
755 if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
758 hdrlen = message->ip.ihl * 4;
759 if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip,
763 message->ip.check = message->udp.len;
766 if (hdrlen + be16toh(message->udp.len) > len ||
767 client_checksum(&message->ip.ttl, be16toh(message->udp.len) + 12))
770 if (be16toh(message->udp.source) != DHCP_PORT_SERVER ||
771 be16toh(message->udp.dest) != DHCP_PORT_CLIENT)
774 if (message->dhcp.op != BOOTREPLY)
777 if (be32toh(message->dhcp.xid) != client->xid)
780 if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
787 static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
793 err = client_verify_headers(client, offer, len);
797 lease = new0(DHCPLease, 1);
801 len = len - DHCP_IP_UDP_SIZE;
802 if (dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
803 lease) != DHCP_OFFER)
806 lease->address = offer->dhcp.yiaddr;
808 if (lease->address == INADDR_ANY ||
809 lease->server_address == INADDR_ANY ||
810 lease->subnet_mask == INADDR_ANY ||
811 lease->lifetime == 0)
814 client->lease = lease;
824 static int client_receive_ack(sd_dhcp_client *client, const uint8_t *buf,
832 if (client->state == DHCP_STATE_RENEWING) {
833 dhcp = (DHCPMessage *)buf;
835 ack = (DHCPPacket *)buf;
837 r = client_verify_headers(client, ack, len);
842 len -= DHCP_IP_UDP_SIZE;
845 lease = new0(DHCPLease, 1);
849 r = dhcp_option_parse(dhcp, len, client_parse_offer, lease);
852 r = DHCP_EVENT_NO_LEASE;
861 lease->address = dhcp->yiaddr;
863 if (lease->address == INADDR_ANY ||
864 lease->server_address == INADDR_ANY ||
865 lease->subnet_mask == INADDR_ANY || lease->lifetime == 0) {
870 r = DHCP_EVENT_IP_ACQUIRE;
872 if (client->lease->address != lease->address ||
873 client->lease->subnet_mask != lease->subnet_mask ||
874 client->lease->router != lease->router) {
875 r = DHCP_EVENT_IP_CHANGE;
881 client->lease = lease;
891 static uint64_t client_compute_timeout(uint64_t request_sent,
894 return request_sent + (lifetime - 3) * USEC_PER_SEC +
895 + (random_u32() & 0x1fffff);
898 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec)
901 uint64_t next_timeout;
903 if (client->lease->lifetime < 10)
906 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
907 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
908 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
910 if (!client->lease->t1)
911 client->lease->t1 = client->lease->lifetime / 2;
913 next_timeout = client_compute_timeout(client->request_sent,
915 if (next_timeout < usec)
918 err = sd_event_add_monotonic(client->event, next_timeout,
920 client_timeout_t1, client,
921 &client->timeout_t1);
925 if (!client->lease->t2)
926 client->lease->t2 = client->lease->lifetime * 7 / 8;
928 if (client->lease->t2 < client->lease->t1)
931 if (client->lease->lifetime < client->lease->t2)
934 next_timeout = client_compute_timeout(client->request_sent,
936 if (next_timeout < usec)
939 err = sd_event_add_monotonic(client->event, next_timeout,
941 client_timeout_t2, client,
942 &client->timeout_t2);
946 next_timeout = client_compute_timeout(client->request_sent,
947 client->lease->lifetime);
948 if (next_timeout < usec)
951 err = sd_event_add_monotonic(client->event, next_timeout,
953 client_timeout_expire, client,
954 &client->timeout_expire);
961 static int client_receive_message(sd_event_source *s, int fd,
962 uint32_t revents, void *userdata)
964 sd_dhcp_client *client = userdata;
965 uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
966 int buflen = sizeof(buf);
967 int len, r = 0, notify_event = 0;
971 len = read(fd, &buf, buflen);
975 r = sd_event_get_now_monotonic(client->event, &time_now);
979 switch (client->state) {
980 case DHCP_STATE_SELECTING:
982 message = (DHCPPacket *)&buf;
984 if (client_receive_offer(client, message, len) >= 0) {
986 client->timeout_resend =
987 sd_event_source_unref(client->timeout_resend);
989 client->state = DHCP_STATE_REQUESTING;
992 r = sd_event_add_monotonic(client->event, time_now, 0,
993 client_timeout_resend,
995 &client->timeout_resend);
1002 case DHCP_STATE_REQUESTING:
1003 case DHCP_STATE_RENEWING:
1004 case DHCP_STATE_REBINDING:
1006 r = client_receive_ack(client, buf, len);
1008 if (r == DHCP_EVENT_NO_LEASE)
1012 client->timeout_resend =
1013 sd_event_source_unref(client->timeout_resend);
1015 if (client->state == DHCP_STATE_REQUESTING)
1016 notify_event = DHCP_EVENT_IP_ACQUIRE;
1017 else if (r != DHCP_EVENT_IP_ACQUIRE)
1020 client->state = DHCP_STATE_BOUND;
1021 client->attempt = 1;
1023 client->last_addr = client->lease->address;
1025 r = client_set_lease_timeouts(client, time_now);
1030 client_notify(client, notify_event);
1032 client->receive_message =
1033 sd_event_source_unref(client->receive_message);
1042 case DHCP_STATE_INIT:
1043 case DHCP_STATE_INIT_REBOOT:
1044 case DHCP_STATE_REBOOTING:
1045 case DHCP_STATE_BOUND:
1051 if (r < 0 || r == DHCP_EVENT_NO_LEASE)
1052 return client_stop(client, r);
1057 int sd_dhcp_client_start(sd_dhcp_client *client)
1061 assert_return(client, -EINVAL);
1062 assert_return(client->index > 0, -EINVAL);
1063 assert_return(client->state == DHCP_STATE_INIT ||
1064 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
1066 client->xid = random_u32();
1068 r = dhcp_network_bind_raw_socket(client->index, &client->link);
1071 client_stop(client, r);
1076 client->start_time = now(CLOCK_MONOTONIC);
1078 return client_initialize_events(client, client->start_time);
1081 int sd_dhcp_client_stop(sd_dhcp_client *client)
1083 return client_stop(client, DHCP_EVENT_STOP);
1086 sd_dhcp_client *sd_dhcp_client_free(sd_dhcp_client *client)
1088 assert_return(client, NULL);
1090 sd_dhcp_client_stop(client);
1092 sd_event_unref(client->event);
1093 free(client->req_opts);
1099 sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
1101 sd_dhcp_client *client;
1103 assert_return(event, NULL);
1105 client = new0(sd_dhcp_client, 1);
1109 client->event = sd_event_ref(event);
1110 client->state = DHCP_STATE_INIT;
1113 client->attempt = 1;
1115 client->req_opts_size = ELEMENTSOF(default_req_opts);
1117 client->req_opts = memdup(default_req_opts, client->req_opts_size);
1118 if (!client->req_opts) {