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_stop(sd_dhcp_client *client, int error)
142 assert_return(client, -EINVAL);
143 assert_return(client->state != DHCP_STATE_INIT &&
144 client->state != DHCP_STATE_INIT_REBOOT, -EALREADY);
146 client->receive_message =
147 sd_event_source_unref(client->receive_message);
153 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
157 switch (client->state) {
159 case DHCP_STATE_INIT:
160 case DHCP_STATE_SELECTING:
162 client->start_time = 0;
163 client->state = DHCP_STATE_INIT;
166 case DHCP_STATE_INIT_REBOOT:
167 case DHCP_STATE_REBOOTING:
168 case DHCP_STATE_REQUESTING:
169 case DHCP_STATE_BOUND:
170 case DHCP_STATE_RENEWING:
171 case DHCP_STATE_REBINDING:
178 client->lease = NULL;
184 static int client_packet_init(sd_dhcp_client *client, uint8_t type,
185 DHCPMessage *message, uint16_t secs,
186 uint8_t **opt, size_t *optlen)
190 *opt = (uint8_t *)(message + 1);
196 message->op = BOOTREQUEST;
198 message->hlen = ETHER_ADDR_LEN;
199 message->xid = htobe32(client->xid);
201 /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
202 refuse to issue an DHCP lease if 'secs' is set to zero */
203 message->secs = htobe16(secs);
205 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
213 err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
218 /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
219 Identifier option is not set */
220 err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
221 ETH_ALEN, &client->mac_addr);
225 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
226 err = dhcp_option_append(opt, optlen,
227 DHCP_OPTION_PARAMETER_REQUEST_LIST,
228 client->req_opts_size,
237 static uint16_t client_checksum(void *buf, int len)
247 for (i = 0; i < len / 2 ; i++)
255 return ~((sum & 0xffff) + (sum >> 16));
258 static void client_append_ip_headers(DHCPPacket *packet, uint16_t len)
260 packet->ip.version = IPVERSION;
261 packet->ip.ihl = DHCP_IP_SIZE / 4;
262 packet->ip.tot_len = htobe16(len);
264 packet->ip.protocol = IPPROTO_UDP;
265 packet->ip.saddr = INADDR_ANY;
266 packet->ip.daddr = INADDR_BROADCAST;
268 packet->udp.source = htobe16(DHCP_PORT_CLIENT);
269 packet->udp.dest = htobe16(DHCP_PORT_SERVER);
270 packet->udp.len = htobe16(len - DHCP_IP_SIZE);
272 packet->ip.check = packet->udp.len;
273 packet->udp.check = client_checksum(&packet->ip.ttl, len - 8);
275 packet->ip.ttl = IPDEFTTL;
276 packet->ip.check = 0;
277 packet->ip.check = client_checksum(&packet->ip, DHCP_IP_SIZE);
280 static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
283 _cleanup_free_ DHCPPacket *discover;
287 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
288 len = sizeof(DHCPPacket) + optlen;
290 discover = malloc0(len);
295 err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
296 secs, &opt, &optlen);
300 if (client->last_addr != INADDR_ANY) {
301 err = dhcp_option_append(&opt, &optlen,
302 DHCP_OPTION_REQUESTED_IP_ADDRESS,
303 4, &client->last_addr);
308 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
312 client_append_ip_headers(discover, len);
314 err = dhcp_network_send_raw_socket(client->fd, &client->link,
320 static int client_send_request(sd_dhcp_client *client, uint16_t secs)
322 _cleanup_free_ DHCPPacket *request;
327 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
328 len = DHCP_MESSAGE_SIZE + optlen;
330 request = malloc0(len);
334 err = client_packet_init(client, DHCP_REQUEST, &request->dhcp, secs,
339 if (client->state == DHCP_STATE_REQUESTING) {
340 err = dhcp_option_append(&opt, &optlen,
341 DHCP_OPTION_REQUESTED_IP_ADDRESS,
342 4, &client->lease->address);
346 err = dhcp_option_append(&opt, &optlen,
347 DHCP_OPTION_SERVER_IDENTIFIER,
348 4, &client->lease->server_address);
353 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
357 client_append_ip_headers(request, len);
359 err = dhcp_network_send_raw_socket(client->fd, &client->link,
365 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
368 sd_dhcp_client *client = userdata;
373 secs = (usec - client->start_time) / USEC_PER_SEC;
375 if (client->attempt < 64)
376 client->attempt *= 2;
378 next_timeout = usec + (client->attempt - 1) * USEC_PER_SEC +
379 (random_u() & 0x1fffff);
381 err = sd_event_add_monotonic(client->event, next_timeout,
383 client_timeout_resend, client,
384 &client->timeout_resend);
388 switch (client->state) {
389 case DHCP_STATE_INIT:
390 err = client_send_discover(client, secs);
392 client->state = DHCP_STATE_SELECTING;
395 if (client->attempt >= 64)
401 case DHCP_STATE_SELECTING:
402 err = client_send_discover(client, secs);
403 if (err < 0 && client->attempt >= 64)
408 case DHCP_STATE_REQUESTING:
409 err = client_send_request(client, secs);
410 if (err < 0 && client->attempt >= 64)
415 case DHCP_STATE_INIT_REBOOT:
416 case DHCP_STATE_REBOOTING:
417 case DHCP_STATE_BOUND:
418 case DHCP_STATE_RENEWING:
419 case DHCP_STATE_REBINDING:
427 client_stop(client, err);
429 /* Errors were dealt with when stopping the client, don't spill
430 errors into the event loop handler */
434 static int client_parse_offer(uint8_t code, uint8_t len, const uint8_t *option,
437 DHCPLease *lease = user_data;
442 case DHCP_OPTION_IP_ADDRESS_LEASE_TIME:
444 memcpy(&val, option, 4);
445 lease->lifetime = be32toh(val);
450 case DHCP_OPTION_SERVER_IDENTIFIER:
452 memcpy(&lease->server_address, option, 4);
456 case DHCP_OPTION_SUBNET_MASK:
458 memcpy(&lease->subnet_mask, option, 4);
462 case DHCP_OPTION_ROUTER:
464 memcpy(&lease->router, option, 4);
472 static int client_receive_offer(sd_dhcp_client *client, DHCPPacket *offer,
478 if (len < (DHCP_IP_UDP_SIZE + DHCP_MESSAGE_SIZE))
481 hdrlen = offer->ip.ihl * 4;
482 if (hdrlen < 20 || hdrlen > len || client_checksum(&offer->ip,
486 offer->ip.check = offer->udp.len;
489 if (hdrlen + be16toh(offer->udp.len) > len ||
490 client_checksum(&offer->ip.ttl, be16toh(offer->udp.len) + 12))
493 if (be16toh(offer->udp.source) != DHCP_PORT_SERVER ||
494 be16toh(offer->udp.dest) != DHCP_PORT_CLIENT)
497 if (offer->dhcp.op != BOOTREPLY)
500 if (be32toh(offer->dhcp.xid) != client->xid)
503 if (memcmp(&offer->dhcp.chaddr[0], &client->mac_addr.ether_addr_octet,
507 lease = new0(DHCPLease, 1);
511 len = len - DHCP_IP_UDP_SIZE;
512 if (dhcp_option_parse(&offer->dhcp, len, client_parse_offer,
513 lease) != DHCP_OFFER)
516 lease->address = offer->dhcp.yiaddr;
518 if (lease->address == INADDR_ANY ||
519 lease->server_address == INADDR_ANY ||
520 lease->subnet_mask == INADDR_ANY ||
521 lease->lifetime == 0)
524 client->lease = lease;
534 static int client_receive_raw_message(sd_event_source *s, int fd,
535 uint32_t revents, void *userdata)
537 sd_dhcp_client *client = userdata;
538 uint8_t buf[sizeof(DHCPPacket) + DHCP_CLIENT_MIN_OPTIONS_SIZE];
539 int buflen = sizeof(buf);
544 len = read(fd, &buf, buflen);
548 err = sd_event_get_now_monotonic(client->event, &time_now);
552 message = (DHCPPacket *)&buf;
554 switch (client->state) {
555 case DHCP_STATE_SELECTING:
557 if (client_receive_offer(client, message, len) >= 0) {
559 client->timeout_resend =
560 sd_event_source_unref(client->timeout_resend);
562 client->state = DHCP_STATE_REQUESTING;
565 err = sd_event_add_monotonic(client->event, time_now, 0,
566 client_timeout_resend,
568 &client->timeout_resend);
575 case DHCP_STATE_INIT:
576 case DHCP_STATE_INIT_REBOOT:
577 case DHCP_STATE_REBOOTING:
578 case DHCP_STATE_REQUESTING:
579 case DHCP_STATE_BOUND:
580 case DHCP_STATE_RENEWING:
581 case DHCP_STATE_REBINDING:
588 return client_stop(client, err);
593 int sd_dhcp_client_start(sd_dhcp_client *client)
597 assert_return(client, -EINVAL);
598 assert_return(client->index >= 0, -EINVAL);
599 assert_return(client->state == DHCP_STATE_INIT ||
600 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
602 client->xid = random_u();
604 client->fd = dhcp_network_bind_raw_socket(client->index,
607 if (client->fd < 0) {
612 err = sd_event_add_io(client->event, client->fd, EPOLLIN,
613 client_receive_raw_message, client,
614 &client->receive_message);
618 client->start_time = now(CLOCK_MONOTONIC);
619 err = sd_event_add_monotonic(client->event, client->start_time, 0,
620 client_timeout_resend, client,
621 &client->timeout_resend);
628 client_stop(client, err);
633 int sd_dhcp_client_stop(sd_dhcp_client *client)
635 return client_stop(client, 0);
638 sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
640 sd_dhcp_client *client;
642 assert_return(event, NULL);
644 client = new0(sd_dhcp_client, 1);
648 client->event = sd_event_ref(event);
649 client->state = DHCP_STATE_INIT;
654 client->req_opts_size = ELEMENTSOF(default_req_opts);
656 client->req_opts = memdup(default_req_opts, client->req_opts_size);
657 if (!client->req_opts) {