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
38 uint32_t server_address;
43 typedef struct DHCPLease DHCPLease;
45 struct sd_dhcp_client {
48 sd_event_source *timeout_resend;
51 union sockaddr_union link;
52 sd_event_source *receive_message;
56 struct ether_addr mac_addr;
63 static const uint8_t default_req_opts[] = {
64 DHCP_OPTION_SUBNET_MASK,
66 DHCP_OPTION_HOST_NAME,
67 DHCP_OPTION_DOMAIN_NAME,
68 DHCP_OPTION_DOMAIN_NAME_SERVER,
69 DHCP_OPTION_NTP_SERVER,
72 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option)
76 assert_return(client, -EINVAL);
77 assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
81 case DHCP_OPTION_OVERLOAD:
82 case DHCP_OPTION_MESSAGE_TYPE:
83 case DHCP_OPTION_PARAMETER_REQUEST_LIST:
91 for (i = 0; i < client->req_opts_size; i++)
92 if (client->req_opts[i] == option)
95 if (!GREEDY_REALLOC(client->req_opts, client->req_opts_size,
96 client->req_opts_size + 1))
99 client->req_opts[client->req_opts_size - 1] = option;
104 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
105 const struct in_addr *last_addr)
107 assert_return(client, -EINVAL);
108 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
111 client->last_addr = last_addr->s_addr;
113 client->last_addr = INADDR_ANY;
118 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index)
120 assert_return(client, -EINVAL);
121 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
122 assert_return(interface_index >= -1, -EINVAL);
124 client->index = interface_index;
129 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
130 const struct ether_addr *addr)
132 assert_return(client, -EINVAL);
133 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
135 memcpy(&client->mac_addr, addr, ETH_ALEN);
140 static int client_notify(sd_dhcp_client *client, int event)
145 static int client_stop(sd_dhcp_client *client, int error)
147 assert_return(client, -EINVAL);
148 assert_return(client->state != DHCP_STATE_INIT &&
149 client->state != DHCP_STATE_INIT_REBOOT, -EALREADY);
151 client->receive_message =
152 sd_event_source_unref(client->receive_message);
158 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
162 switch (client->state) {
164 case DHCP_STATE_INIT:
165 case DHCP_STATE_SELECTING:
166 case DHCP_STATE_REQUESTING:
168 client->start_time = 0;
169 client->state = DHCP_STATE_INIT;
172 case DHCP_STATE_INIT_REBOOT:
173 case DHCP_STATE_REBOOTING:
174 case DHCP_STATE_BOUND:
175 case DHCP_STATE_RENEWING:
176 case DHCP_STATE_REBINDING:
183 client->lease = NULL;
189 static int client_packet_init(sd_dhcp_client *client, uint8_t type,
190 DHCPMessage *message, uint16_t secs,
191 uint8_t **opt, size_t *optlen)
196 *opt = (uint8_t *)(message + 1);
202 message->op = BOOTREQUEST;
204 message->hlen = ETHER_ADDR_LEN;
205 message->xid = htobe32(client->xid);
207 /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
208 refuse to issue an DHCP lease if 'secs' is set to zero */
209 message->secs = htobe16(secs);
211 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
219 err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
224 /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
225 Identifier option is not set */
226 err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
227 ETH_ALEN, &client->mac_addr);
231 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
232 err = dhcp_option_append(opt, optlen,
233 DHCP_OPTION_PARAMETER_REQUEST_LIST,
234 client->req_opts_size,
239 /* Some DHCP servers will send bigger DHCP packets than the
240 defined default size unless the Maximum Messge Size option
241 is explicitely set */
242 max_size = htobe16(DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE +
243 DHCP_CLIENT_MIN_OPTIONS_SIZE);
244 err = dhcp_option_append(opt, optlen,
245 DHCP_OPTION_MAXIMUM_MESSAGE_SIZE,
254 static uint16_t client_checksum(void *buf, int len)
264 for (i = 0; i < len / 2 ; i++)
272 return ~((sum & 0xffff) + (sum >> 16));
275 static void client_append_ip_headers(DHCPPacket *packet, uint16_t len)
277 packet->ip.version = IPVERSION;
278 packet->ip.ihl = DHCP_IP_SIZE / 4;
279 packet->ip.tot_len = htobe16(len);
281 packet->ip.protocol = IPPROTO_UDP;
282 packet->ip.saddr = INADDR_ANY;
283 packet->ip.daddr = INADDR_BROADCAST;
285 packet->udp.source = htobe16(DHCP_PORT_CLIENT);
286 packet->udp.dest = htobe16(DHCP_PORT_SERVER);
287 packet->udp.len = htobe16(len - DHCP_IP_SIZE);
289 packet->ip.check = packet->udp.len;
290 packet->udp.check = client_checksum(&packet->ip.ttl, len - 8);
292 packet->ip.ttl = IPDEFTTL;
293 packet->ip.check = 0;
294 packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE);
297 static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
300 _cleanup_free_ DHCPPacket *discover;
304 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
305 len = sizeof(DHCPPacket) + optlen;
307 discover = malloc0(len);
312 err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
313 secs, &opt, &optlen);
317 if (client->last_addr != INADDR_ANY) {
318 err = dhcp_option_append(&opt, &optlen,
319 DHCP_OPTION_REQUESTED_IP_ADDRESS,
320 4, &client->last_addr);
325 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
329 client_append_ip_headers(discover, len);
331 err = dhcp_network_send_raw_socket(client->fd, &client->link,
337 static int client_send_request(sd_dhcp_client *client, uint16_t secs)
339 _cleanup_free_ DHCPPacket *request;
344 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
345 len = DHCP_MESSAGE_SIZE + optlen;
347 request = malloc0(len);
351 err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs,
356 if (client->state == DHCP_STATE_REQUESTING) {
357 err = dhcp_option_append(&opt, &optlen,
358 DHCP_OPTION_REQUESTED_IP_ADDRESS,
359 4, &client->lease->address);
363 err = dhcp_option_append(&opt, &optlen,
364 DHCP_OPTION_SERVER_IDENTIFIER,
365 4, &client->lease->server_address);
370 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
374 client_append_ip_headers(request, len);
376 err = dhcp_network_send_raw_socket(client->fd, &client->link,
382 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
385 sd_dhcp_client *client = userdata;
390 secs = (usec - client->start_time) / USEC_PER_SEC;
392 if (client->attempt < 64)
393 client->attempt *= 2;
395 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC +
396 (random_u() & 0x1fffff);
398 err = sd_event_add_monotonic(client->event, next_timeout,
400 client_timeout_resend, client,
401 &client->timeout_resend);
405 switch (client->state) {
406 case DHCP_STATE_INIT:
407 err = client_send_discover(client, secs);
409 client->state = DHCP_STATE_SELECTING;
412 if (client->attempt >= 64)
418 case DHCP_STATE_SELECTING:
419 err = client_send_discover(client, secs);
420 if (err < 0 && client->attempt >= 64)
425 case DHCP_STATE_REQUESTING:
426 err = client_send_request(client, secs);
427 if (err < 0 && client->attempt >= 64)
432 case DHCP_STATE_INIT_REBOOT:
433 case DHCP_STATE_REBOOTING:
434 case DHCP_STATE_BOUND:
435 case DHCP_STATE_RENEWING:
436 case DHCP_STATE_REBINDING:
444 client_stop(client, err);
446 /* Errors were dealt with when stopping the client, don't spill
447 errors into the event loop handler */
451 static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option,
454 DHCPLease *lease = user_data;
459 case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
461 memcpy(&val, option, 4);
462 lease->lifetime = be32toh(val);
467 case DHCP_OPTION_SERVER_IDENTIFIER:
469 memcpy(&lease->server_address, option, 4);
473 case DHCP_OPTION_SUBNET_MASK:
475 memcpy(&lease->subnet_mask, option, 4);
479 case DHCP_OPTION_ROUTER:
481 memcpy(&lease->router, option, 4);
489 static int client_verify_headers(sd_dhcp_client *client, DHCPPacket *message,
494 if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
497 hdrlen = message->ip.ihl * 4;
498 if (hdrlen < 20 || hdrlen > len || client_checksum(&message->ip,
502 message->ip.check = message->udp.len;
505 if (hdrlen + be16toh(message->udp.len) > len ||
506 client_checksum(&message->ip.ttl, be16toh(message->udp.len) + 12))
509 if (be16toh(message->udp.source) != DHCP_PORT_SERVER ||
510 be16toh(message->udp.dest) != DHCP_PORT_CLIENT)
513 if (message->dhcp.op != BOOTREPLY)
516 if (be32toh(message->dhcp.xid) != client->xid)
519 if (memcmp(&message->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
526 static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
532 err = client_verify_headers(client, offer, len);
536 lease = new0(DHCPLease, 1);
540 len = len - DHCP_IP_UDP_SIZE;
541 if (dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
542 lease) != DHCP_OFFER)
545 lease->address = offer->dhcp.yiaddr;
547 if (lease->address == INADDR_ANY ||
548 lease->server_address == INADDR_ANY ||
549 lease->subnet_mask == INADDR_ANY ||
550 lease->lifetime == 0)
553 client->lease = lease;
563 static int client_receive_ack(sd_dhcp_client *client, DHCPPacket *offer,
569 r = client_verify_headers(client, offer, len);
573 lease = new0(DHCPLease, 1);
577 len = len - DHCP_IP_UDP_SIZE;
578 r = dhcp_option_parse(&offer->dhcp, len, client_parse_offer, lease);
583 lease->address = offer->dhcp.yiaddr;
585 if (lease->address == INADDR_ANY ||
586 lease->server_address == INADDR_ANY ||
587 lease->subnet_mask == INADDR_ANY || lease->lifetime == 0) {
592 r = DHCP_EVENT_IP_ACQUIRE;
594 if (client->lease->address != lease->address ||
595 client->lease->subnet_mask != lease->subnet_mask ||
596 client->lease->router != lease->router) {
597 r = DHCP_EVENT_IP_CHANGE;
603 client->lease = lease;
613 static int client_receive_raw_message(sd_event_source *s, int fd,
614 uint32_t revents, void *userdata)
616 sd_dhcp_client *client = userdata;
617 uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
618 int buflen = sizeof(buf);
623 len = read(fd, &buf, buflen);
627 r = sd_event_get_now_monotonic(client->event, &time_now);
631 message = (DHCPPacket *)&buf;
633 switch (client->state) {
634 case DHCP_STATE_SELECTING:
636 if (client_receive_offer(client, message, len) >= 0) {
638 client->timeout_resend =
639 sd_event_source_unref(client->timeout_resend);
641 client->state = DHCP_STATE_REQUESTING;
644 r = sd_event_add_monotonic(client->event, time_now, 0,
645 client_timeout_resend,
647 &client->timeout_resend);
654 case DHCP_STATE_REQUESTING:
656 r = client_receive_ack(client, message, len);
657 if (r == DHCP_EVENT_NO_LEASE)
661 client->timeout_resend =
662 sd_event_source_unref(client->timeout_resend);
664 client->state = DHCP_STATE_BOUND;
667 client->last_addr = client->lease->address;
669 client_notify(client, DHCP_EVENT_IP_ACQUIRE);
673 client->receive_message =
674 sd_event_source_unref(client->receive_message);
678 case DHCP_STATE_INIT:
679 case DHCP_STATE_INIT_REBOOT:
680 case DHCP_STATE_REBOOTING:
681 case DHCP_STATE_BOUND:
682 case DHCP_STATE_RENEWING:
683 case DHCP_STATE_REBINDING:
690 return client_stop(client, r);
695 int sd_dhcp_client_start(sd_dhcp_client *client)
699 assert_return(client, -EINVAL);
700 assert_return(client->index >= 0, -EINVAL);
701 assert_return(client->state == DHCP_STATE_INIT ||
702 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
704 client->xid = random_u();
706 client->fd = dhcp_network_bind_raw_socket(client->index,
709 if (client->fd < 0) {
714 err = sd_event_add_io(client->event, client->fd, EPOLLIN,
715 client_receive_raw_message, client,
716 &client->receive_message);
720 client->start_time = now(CLOCK_MONOTONIC);
721 err = sd_event_add_monotonic(client->event, client->start_time, 0,
722 client_timeout_resend, client,
723 &client->timeout_resend);
730 client_stop(client, err);
735 int sd_dhcp_client_stop(sd_dhcp_client *client)
737 return client_stop(client, 0);
740 sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
742 sd_dhcp_client *client;
744 assert_return(event, NULL);
746 client = new0(sd_dhcp_client, 1);
750 client->event = sd_event_ref(event);
751 client->state = DHCP_STATE_INIT;
756 client->req_opts_size = ELEMENTSOF(default_req_opts);
758 client->req_opts = memdup(default_req_opts, client->req_opts_size);
759 if (!client->req_opts) {