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
35 struct sd_dhcp_client {
38 sd_event_source *timeout_resend;
43 struct ether_addr mac_addr;
48 static const uint8_t default_req_opts[] = {
49 DHCP_OPTION_SUBNET_MASK,
51 DHCP_OPTION_HOST_NAME,
52 DHCP_OPTION_DOMAIN_NAME,
53 DHCP_OPTION_DOMAIN_NAME_SERVER,
54 DHCP_OPTION_NTP_SERVER,
57 int sd_dhcp_client_set_request_option(sd_dhcp_client *client, uint8_t option)
61 assert_return(client, -EINVAL);
62 assert_return (client->state == DHCP_STATE_INIT, -EBUSY);
66 case DHCP_OPTION_OVERLOAD:
67 case DHCP_OPTION_MESSAGE_TYPE:
68 case DHCP_OPTION_PARAMETER_REQUEST_LIST:
76 for (i = 0; i < client->req_opts_size; i++)
77 if (client->req_opts[i] == option)
80 if (!GREEDY_REALLOC(client->req_opts, client->req_opts_size,
81 client->req_opts_size + 1))
84 client->req_opts[client->req_opts_size - 1] = option;
89 int sd_dhcp_client_set_request_address(sd_dhcp_client *client,
90 const struct in_addr *last_addr)
92 assert_return(client, -EINVAL);
93 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
96 client->last_addr = last_addr->s_addr;
98 client->last_addr = INADDR_ANY;
103 int sd_dhcp_client_set_index(sd_dhcp_client *client, int interface_index)
105 assert_return(client, -EINVAL);
106 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
107 assert_return(interface_index >= -1, -EINVAL);
109 client->index = interface_index;
114 int sd_dhcp_client_set_mac(sd_dhcp_client *client,
115 const struct ether_addr *addr)
117 assert_return(client, -EINVAL);
118 assert_return(client->state == DHCP_STATE_INIT, -EBUSY);
120 memcpy(&client->mac_addr, addr, ETH_ALEN);
125 static int client_stop(sd_dhcp_client *client, int error)
127 assert_return(client, -EINVAL);
128 assert_return(client->state != DHCP_STATE_INIT &&
129 client->state != DHCP_STATE_INIT_REBOOT, -EALREADY);
131 client->timeout_resend = sd_event_source_unref(client->timeout_resend);
133 switch (client->state) {
135 case DHCP_STATE_INIT:
136 case DHCP_STATE_SELECTING:
138 client->state = DHCP_STATE_INIT;
141 case DHCP_STATE_INIT_REBOOT:
142 case DHCP_STATE_REBOOTING:
143 case DHCP_STATE_REQUESTING:
144 case DHCP_STATE_BOUND:
145 case DHCP_STATE_RENEWING:
146 case DHCP_STATE_REBINDING:
154 static int client_packet_init(sd_dhcp_client *client, uint8_t type,
155 DHCPMessage *message, uint16_t secs,
156 uint8_t **opt, size_t *optlen)
160 *opt = (uint8_t *)(message + 1);
166 message->op = BOOTREQUEST;
168 message->hlen = ETHER_ADDR_LEN;
169 message->xid = htobe32(client->xid);
171 /* Although 'secs' field is a SHOULD in RFC 2131, certain DHCP servers
172 refuse to issue an DHCP lease if 'secs' is set to zero */
173 message->secs = htobe16(secs);
175 memcpy(&message->chaddr, &client->mac_addr, ETH_ALEN);
183 err = dhcp_option_append(opt, optlen, DHCP_OPTION_MESSAGE_TYPE, 1,
188 /* Some DHCP servers will refuse to issue an DHCP lease if the Cliient
189 Identifier option is not set */
190 err = dhcp_option_append(opt, optlen, DHCP_OPTION_CLIENT_IDENTIFIER,
191 ETH_ALEN, &client->mac_addr);
195 if (type == DHCP_DISCOVER || type == DHCP_REQUEST) {
196 err = dhcp_option_append(opt, optlen,
197 DHCP_OPTION_PARAMETER_REQUEST_LIST,
198 client->req_opts_size,
207 static uint16_t client_checksum(void *buf, int len)
217 for (i = 0; i < len / 2 ; i++)
225 return ~((sum & 0xffff) + (sum >> 16));
228 static int client_send_discover(sd_dhcp_client *client, uint16_t secs)
231 _cleanup_free_ DHCPPacket *discover;
235 optlen = DHCP_CLIENT_MIN_OPTIONS_SIZE;
236 len = sizeof(DHCPPacket) + optlen;
238 discover = malloc0(len);
243 err = client_packet_init(client, DHCP_DISCOVER, &discover->dhcp,
244 secs, &opt, &optlen);
248 if (client->last_addr != INADDR_ANY) {
249 err = dhcp_option_append(&opt, &optlen,
250 DHCP_OPTION_REQUESTED_IP_ADDRESS,
251 4, &client->last_addr);
256 err = dhcp_option_append(&opt, &optlen, DHCP_OPTION_END, 0, NULL);
260 discover->ip.version = IPVERSION;
261 discover->ip.ihl = sizeof(discover->ip) >> 2;
262 discover->ip.tot_len = htobe16(len);
264 discover->ip.protocol = IPPROTO_UDP;
265 discover->ip.saddr = INADDR_ANY;
266 discover->ip.daddr = INADDR_BROADCAST;
268 discover->udp.source = htobe16(DHCP_PORT_CLIENT);
269 discover->udp.dest = htobe16(DHCP_PORT_SERVER);
270 discover->udp.len = htobe16(len - sizeof(discover->ip));
272 discover->ip.check = discover->udp.len;
273 discover->udp.check = client_checksum(&discover->ip.ttl,
276 discover->ip.ttl = IPDEFTTL;
277 discover->ip.check = 0;
278 discover->ip.check = client_checksum(&discover->ip,
279 sizeof(discover->ip));
281 err = dhcp_network_send_raw_packet(client->index, discover, len);
286 static int client_timeout_resend(sd_event_source *s, uint64_t usec,
289 sd_dhcp_client *client = userdata;
294 switch (client->state) {
295 case DHCP_STATE_INIT:
296 case DHCP_STATE_SELECTING:
298 if (!client->start_time)
299 client->start_time = usec;
301 secs = (usec - client->start_time) / USEC_PER_SEC;
303 next_timeout = usec + 2 * USEC_PER_SEC + (random() & 0x1fffff);
305 err = sd_event_add_monotonic(client->event, next_timeout,
307 client_timeout_resend, client,
308 &client->timeout_resend);
312 if (client_send_discover(client, secs) >= 0)
313 client->state = DHCP_STATE_SELECTING;
317 case DHCP_STATE_INIT_REBOOT:
318 case DHCP_STATE_REBOOTING:
319 case DHCP_STATE_REQUESTING:
320 case DHCP_STATE_BOUND:
321 case DHCP_STATE_RENEWING:
322 case DHCP_STATE_REBINDING:
330 client_stop(client, err);
332 /* Errors were dealt with when stopping the client, don't spill
333 errors into the event loop handler */
337 int sd_dhcp_client_start(sd_dhcp_client *client)
341 assert_return(client, -EINVAL);
342 assert_return(client->index >= 0, -EINVAL);
343 assert_return(client->state == DHCP_STATE_INIT ||
344 client->state == DHCP_STATE_INIT_REBOOT, -EBUSY);
346 client->xid = random_u();
348 err = sd_event_add_monotonic(client->event, now(CLOCK_MONOTONIC), 0,
349 client_timeout_resend, client,
350 &client->timeout_resend);
357 client_stop(client, err);
362 int sd_dhcp_client_stop(sd_dhcp_client *client)
364 return client_stop(client, 0);
367 sd_dhcp_client *sd_dhcp_client_new(sd_event *event)
369 sd_dhcp_client *client;
371 assert_return(event, NULL);
373 client = new0(sd_dhcp_client, 1);
377 client->event = sd_event_ref(event);
378 client->state = DHCP_STATE_INIT;
381 client->req_opts_size = ELEMENTSOF(default_req_opts);
383 client->req_opts = memdup(default_req_opts, client->req_opts_size);
384 if (!client->req_opts) {