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 uint32_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;
69 static const uint8_t default_req_opts[] = {
70 DHCP_OPTION_SUBNET_MASK,
72 DHCP_OPTION_HOST_NAME,
73 DHCP_OPTION_DOMAIN_NAME,
74 DHCP_OPTION_DOMAIN_NAME_SERVER,
75 DHCP_OPTION_NTP_SERVER,
78 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option)
82 assert_return(client, -EINVAL);
83 assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
87 case DHCP_OPTION_OVERLOAD:
88 case DHCP_OPTION_MESSAGE_TYPE:
89 case DHCP_OPTION_PARAMETER_REQUEST_LIST:
97 for (i = 0; i < client->req_opts_size; i++)
98 if (client->req_opts[i] == option)
101 if (!GREEDY_REALLOC(client->req_opts, client->req_opts_size,
102 client->req_opts_size + 1))
105 client->req_opts[client->req_opts_size - 1] = option;
110 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
111 const struct in_addr *last_addr)
113 assert_return(client, -EINVAL);
114 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
117 client->last_addr = last_addr->s_addr;
119 client->last_addr = INADDR_ANY;
124 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index)
126 assert_return(client, -EINVAL);
127 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
128 assert_return(interface_index >= -1, -EINVAL);
130 client->index = interface_index;
135 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
136 const struct ether_addr *addr)
138 assert_return(client, -EINVAL);
139 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
141 memcpy(&client->mac_addr, addr, ETH_ALEN);
146 static int client_notify(sd_dhcp_client *client, int event)
151 static int client_stop(sd_dhcp_client *client, int error)
153 assert_return(client, -EINVAL);
154 assert_return(client->state != DHCP_STATE_INIT &&
155 client->state != DHCP_STATE_INIT_REBOOT, -EALREADY);
157 client->receive_message =
158 sd_event_source_unref(client->receive_message);
164 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
166 client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
167 client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
168 client->timeout_expire = sd_event_source_unref(client->timeout_expire);
172 switch (client->state) {
174 case DHCP_STATE_INIT:
175 case DHCP_STATE_SELECTING:
176 case DHCP_STATE_REQUESTING:
177 case DHCP_STATE_BOUND:
179 client->start_time = 0;
180 client->state = DHCP_STATE_INIT;
183 case DHCP_STATE_INIT_REBOOT:
184 case DHCP_STATE_REBOOTING:
185 case DHCP_STATE_RENEWING:
186 case DHCP_STATE_REBINDING:
193 client->lease = NULL;
199 static int client_packet_init(sd_dhcp_client *client, uint8_t type,
200 DHCPMessage *message, uint16_t secs,
201 uint8_t **opt, size_t *optlen)
206 *opt = (uint8_t *)(message + 1);
212 message->op = BOOTREQUEST;
214 message->hlen = ETHER_ADDR_LEN;
215 message->xid = htobe32(client->xid);
217 /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
218 refuse to issue an DHCP lease if 'secs' is set to zero */
219 message->secs = htobe16(secs);
221 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
229 err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
234 /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
235 Identifier option is not set */
236 err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
237 ETH_ALEN, &client->mac_addr);
241 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
242 err = dhcp_option_append(opt, optlen,
243 DHCP_OPTION_PARAMETER_REQUEST_LIST,
244 client->req_opts_size,
249 /* Some DHCP servers will send bigger DHCP packets than the
250 defined default size unless the Maximum Messge Size option
251 is explicitely set */
252 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
253 DHCP_CLIENT_MIN_OPTIONS_SIZE);
254 err = dhcp_option_append(opt, optlen,
255 DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
264 static uint16_t client_checksum(void *buf, int len)
274 for (i = 0; i < len / 2 ; i++)
282 return ~((sum & 0xffff) + (sum >> 16));
285 static void client_append_ip_headers(DHCPPacket *packet, uint16_t len)
287 packet->ip.version = IPVERSION;
288 packet->ip.ihl = DHCP_IP_SIZE / 4;
289 packet->ip.tot_len = htobe16(len);
291 packet->ip.protocol = IPPROTO_UDP;
292 packet->ip.saddr = INADDR_ANY;
293 packet->ip.daddr = INADDR_BROADCAST;
295 packet->udp.source = htobe16(DHCP_PORT_CLIENT);
296 packet->udp.dest = htobe16(DHCP_PORT_SERVER);
297 packet->udp.len = htobe16(len - DHCP_IP_SIZE);
299 packet->ip.check = packet->udp.len;
300 packet->udp.check = client_checksum(&packet->ip.ttl, len - 8);
302 packet->ip.ttl = IPDEFTTL;
303 packet->ip.check = 0;
304 packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE);
307 static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
310 _cleanup_free_ DHCPPacket *discover;
314 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
315 len = sizeof(DHCPPacket) + optlen;
317 discover = malloc0(len);
322 err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
323 secs, &opt, &optlen);
327 if (client->last_addr != INADDR_ANY) {
328 err = dhcp_option_append(&opt, &optlen,
329 DHCP_OPTION_REQUESTED_IP_ADDRESS,
330 4, &client->last_addr);
335 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
339 client_append_ip_headers(discover, len);
341 err = dhcp_network_send_raw_socket(client->fd, &client->link,
347 static int client_send_request(sd_dhcp_client *client, uint16_t secs)
349 _cleanup_free_ DHCPPacket *request;
354 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
355 len = DHCP_MESSAGE_SIZE + optlen;
357 request = malloc0(len);
361 err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs,
366 if (client->state == DHCP_STATE_REQUESTING) {
367 err = dhcp_option_append(&opt, &optlen,
368 DHCP_OPTION_REQUESTED_IP_ADDRESS,
369 4, &client->lease->address);
373 err = dhcp_option_append(&opt, &optlen,
374 DHCP_OPTION_SERVER_IDENTIFIER,
375 4, &client->lease->server_address);
380 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
384 client_append_ip_headers(request, len);
386 err = dhcp_network_send_raw_socket(client->fd, &client->link,
392 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
395 sd_dhcp_client *client = userdata;
400 secs = (usec - client->start_time) / USEC_PER_SEC;
402 if (client->attempt < 64)
403 client->attempt *= 2;
405 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC +
406 (random_u() & 0x1fffff);
408 err = sd_event_add_monotonic(client->event, next_timeout,
410 client_timeout_resend, client,
411 &client->timeout_resend);
415 switch (client->state) {
416 case DHCP_STATE_INIT:
417 err = client_send_discover(client, secs);
419 client->state = DHCP_STATE_SELECTING;
422 if (client->attempt >= 64)
428 case DHCP_STATE_SELECTING:
429 err = client_send_discover(client, secs);
430 if (err < 0 && client->attempt >= 64)
435 case DHCP_STATE_REQUESTING:
436 err = client_send_request(client, secs);
437 if (err < 0 && client->attempt >= 64)
440 client->request_sent = usec;
444 case DHCP_STATE_INIT_REBOOT:
445 case DHCP_STATE_REBOOTING:
446 case DHCP_STATE_BOUND:
447 case DHCP_STATE_RENEWING:
448 case DHCP_STATE_REBINDING:
456 client_stop(client, err);
458 /* Errors were dealt with when stopping the client, don't spill
459 errors into the event loop handler */
463 static int client_timeout_expire(sd_event_source *s, uint64_t usec,
469 static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata)
474 static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata)
479 static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option,
482 DHCPLease *lease = user_data;
487 case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
489 memcpy(&val, option, 4);
490 lease->lifetime = be32toh(val);
495 case DHCP_OPTION_SERVER_IDENTIFIER:
497 memcpy(&lease->server_address, option, 4);
501 case DHCP_OPTION_SUBNET_MASK:
503 memcpy(&lease->subnet_mask, option, 4);
507 case DHCP_OPTION_ROUTER:
509 memcpy(&lease->router, option, 4);
513 case DHCP_OPTION_RENEWAL_T1_TIME:
515 memcpy(&val, option, 4);
516 lease->t1 = be32toh(val);
521 case DHCP_OPTION_REBINDING_T2_TIME:
523 memcpy(&val, option, 4);
524 lease->t2 = be32toh(val);
533 static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
538 if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
541 hdrlen = message->ip.ihl * 4;
542 if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip,
546 message->ip.check = message->udp.len;
549 if (hdrlen + be16toh(message->udp.len) > len ||
550 client_checksum(&message->ip.ttl, be16toh(message->udp.len) + 12))
553 if (be16toh(message->udp.source) != DHCP_PORT_SERVER ||
554 be16toh(message->udp.dest) != DHCP_PORT_CLIENT)
557 if (message->dhcp.op != BOOTREPLY)
560 if (be32toh(message->dhcp.xid) != client->xid)
563 if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
570 static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
576 err = client_verify_headers(client, offer, len);
580 lease = new0(DHCPLease, 1);
584 len = len - DHCP_IP_UDP_SIZE;
585 if (dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
586 lease) != DHCP_OFFER)
589 lease->address = offer->dhcp.yiaddr;
591 if (lease->address == INADDR_ANY ||
592 lease->server_address == INADDR_ANY ||
593 lease->subnet_mask == INADDR_ANY ||
594 lease->lifetime == 0)
597 client->lease = lease;
607 static int client_receive_ack(sd_dhcp_client *client, DHCPPacket *offer,
613 r = client_verify_headers(client, offer, len);
617 lease = new0(DHCPLease, 1);
621 len = len - DHCP_IP_UDP_SIZE;
622 r = dhcp_option_parse(&offer->dhcp, len, client_parse_offer, lease);
627 lease->address = offer->dhcp.yiaddr;
629 if (lease->address == INADDR_ANY ||
630 lease->server_address == INADDR_ANY ||
631 lease->subnet_mask == INADDR_ANY || lease->lifetime == 0) {
636 r = DHCP_EVENT_IP_ACQUIRE;
638 if (client->lease->address != lease->address ||
639 client->lease->subnet_mask != lease->subnet_mask ||
640 client->lease->router != lease->router) {
641 r = DHCP_EVENT_IP_CHANGE;
647 client->lease = lease;
657 static uint64_t client_compute_timeout(uint64_t request_sent,
660 return request_sent + (lifetime - 3) * USEC_PER_SEC +
661 + (random_u() & 0x1fffff);
664 static int client_set_lease_timeouts(sd_dhcp_client *client, uint64_t usec)
667 uint64_t next_timeout;
669 if (client->lease->lifetime < 10)
672 if (!client->lease->t1)
673 client->lease->t1 = client->lease->lifetime / 2;
675 next_timeout = client_compute_timeout(client->request_sent,
677 if (next_timeout < usec)
680 err = sd_event_add_monotonic(client->event, next_timeout,
682 client_timeout_t1, client,
683 &client->timeout_t1);
687 if (!client->lease->t2)
688 client->lease->t2 = client->lease->lifetime * 7 / 8;
690 if (client->lease->t2 < client->lease->t1)
693 if (client->lease->lifetime < client->lease->t2)
696 next_timeout = client_compute_timeout(client->request_sent,
698 if (next_timeout < usec)
701 err = sd_event_add_monotonic(client->event, next_timeout,
703 client_timeout_t2, client,
704 &client->timeout_t2);
708 next_timeout = client_compute_timeout(client->request_sent,
709 client->lease->lifetime);
710 if (next_timeout < usec)
713 err = sd_event_add_monotonic(client->event, next_timeout,
715 client_timeout_expire, client,
716 &client->timeout_expire);
723 static int client_receive_raw_message(sd_event_source *s, int fd,
724 uint32_t revents, void *userdata)
726 sd_dhcp_client *client = userdata;
727 uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
728 int buflen = sizeof(buf);
733 len = read(fd, &buf, buflen);
737 r = sd_event_get_now_monotonic(client->event, &time_now);
741 message = (DHCPPacket *)&buf;
743 switch (client->state) {
744 case DHCP_STATE_SELECTING:
746 if (client_receive_offer(client, message, len) >= 0) {
748 client->timeout_resend =
749 sd_event_source_unref(client->timeout_resend);
751 client->state = DHCP_STATE_REQUESTING;
754 r = sd_event_add_monotonic(client->event, time_now, 0,
755 client_timeout_resend,
757 &client->timeout_resend);
764 case DHCP_STATE_REQUESTING:
766 r = client_receive_ack(client, message, len);
767 if (r == DHCP_EVENT_NO_LEASE)
771 client->timeout_resend =
772 sd_event_source_unref(client->timeout_resend);
774 client->state = DHCP_STATE_BOUND;
777 client->last_addr = client->lease->address;
779 r = client_set_lease_timeouts(client, time_now);
783 client_notify(client, DHCP_EVENT_IP_ACQUIRE);
787 client->receive_message =
788 sd_event_source_unref(client->receive_message);
792 case DHCP_STATE_INIT:
793 case DHCP_STATE_INIT_REBOOT:
794 case DHCP_STATE_REBOOTING:
795 case DHCP_STATE_BOUND:
796 case DHCP_STATE_RENEWING:
797 case DHCP_STATE_REBINDING:
804 return client_stop(client, r);
809 int sd_dhcp_client_start(sd_dhcp_client *client)
813 assert_return(client, -EINVAL);
814 assert_return(client->index >= 0, -EINVAL);
815 assert_return(client->state == DHCP_STATE_INIT ||
816 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
818 client->xid = random_u();
820 client->fd = dhcp_network_bind_raw_socket(client->index,
823 if (client->fd < 0) {
828 err = sd_event_add_io(client->event, client->fd, EPOLLIN,
829 client_receive_raw_message, client,
830 &client->receive_message);
834 client->start_time = now(CLOCK_MONOTONIC);
835 err = sd_event_add_monotonic(client->event, client->start_time, 0,
836 client_timeout_resend, client,
837 &client->timeout_resend);
844 client_stop(client, err);
849 int sd_dhcp_client_stop(sd_dhcp_client *client)
851 return client_stop(client, 0);
854 sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
856 sd_dhcp_client *client;
858 assert_return(event, NULL);
860 client = new0(sd_dhcp_client, 1);
864 client->event = sd_event_ref(event);
865 client->state = DHCP_STATE_INIT;
870 client->req_opts_size = ELEMENTSOF(default_req_opts);
872 client->req_opts = memdup(default_req_opts, client->req_opts_size);
873 if (!client->req_opts) {