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b44cd882 TG |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright (C) 2013 Intel Corporation. All rights reserved. | |
7 | Copyright (C) 2014 Tom Gundersen | |
8 | ||
9 | systemd is free software; you can redistribute it and/or modify it | |
10 | under the terms of the GNU Lesser General Public License as published by | |
11 | the Free Software Foundation; either version 2.1 of the License, or | |
12 | (at your option) any later version. | |
13 | ||
14 | systemd is distributed in the hope that it will be useful, but | |
15 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | Lesser General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU Lesser General Public License | |
20 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
21 | ***/ | |
22 | ||
ff734080 TG |
23 | #include <sys/ioctl.h> |
24 | ||
87322b3a TG |
25 | #include "siphash24.h" |
26 | ||
b44cd882 TG |
27 | #include "sd-dhcp-server.h" |
28 | #include "dhcp-server-internal.h" | |
ff734080 | 29 | #include "dhcp-internal.h" |
b44cd882 | 30 | |
d122f9ee | 31 | #define DHCP_DEFAULT_LEASE_TIME 3600 /* one hour */ |
4dc35568 | 32 | |
a6f1e036 TG |
33 | int sd_dhcp_server_set_lease_pool(sd_dhcp_server *server, |
34 | struct in_addr *address, | |
2dead812 TG |
35 | size_t size) { |
36 | assert_return(server, -EINVAL); | |
37 | assert_return(address, -EINVAL); | |
38 | assert_return(address->s_addr, -EINVAL); | |
39 | assert_return(size, -EINVAL); | |
40 | assert_return(server->pool_start == htobe32(INADDR_ANY), -EBUSY); | |
41 | assert_return(!server->pool_size, -EBUSY); | |
87322b3a TG |
42 | assert_return(!server->bound_leases, -EBUSY); |
43 | ||
44 | server->bound_leases = new0(DHCPLease*, size); | |
45 | if (!server->bound_leases) | |
46 | return -ENOMEM; | |
2dead812 TG |
47 | |
48 | server->pool_start = address->s_addr; | |
49 | server->pool_size = size; | |
50 | ||
51 | return 0; | |
52 | } | |
53 | ||
a6f1e036 TG |
54 | int sd_dhcp_server_set_address(sd_dhcp_server *server, struct in_addr *address, |
55 | unsigned char prefixlen) { | |
20af7091 TG |
56 | assert_return(server, -EINVAL); |
57 | assert_return(address, -EINVAL); | |
58 | assert_return(address->s_addr, -EINVAL); | |
59b8f6b6 | 59 | assert_return(prefixlen <= 32, -ERANGE); |
20af7091 | 60 | assert_return(server->address == htobe32(INADDR_ANY), -EBUSY); |
59b8f6b6 | 61 | assert_return(server->netmask == htobe32(INADDR_ANY), -EBUSY); |
20af7091 TG |
62 | |
63 | server->address = address->s_addr; | |
59b8f6b6 | 64 | server->netmask = htobe32(0xfffffffflu << (32 - prefixlen)); |
20af7091 TG |
65 | |
66 | return 0; | |
67 | } | |
68 | ||
7c16313f | 69 | bool sd_dhcp_server_is_running(sd_dhcp_server *server) { |
75677581 | 70 | assert_return(server, false); |
7c16313f TG |
71 | |
72 | return !!server->receive_message; | |
73 | } | |
74 | ||
b44cd882 TG |
75 | sd_dhcp_server *sd_dhcp_server_ref(sd_dhcp_server *server) { |
76 | if (server) | |
77 | assert_se(REFCNT_INC(server->n_ref) >= 2); | |
78 | ||
79 | return server; | |
80 | } | |
81 | ||
a6f1e036 TG |
82 | unsigned long client_id_hash_func(const void *p, |
83 | const uint8_t hash_key[HASH_KEY_SIZE]) { | |
87322b3a TG |
84 | uint64_t u; |
85 | const DHCPClientId *id = p; | |
86 | ||
87 | assert(id); | |
88 | assert(id->length); | |
89 | assert(id->data); | |
90 | ||
91 | siphash24((uint8_t*) &u, id->data, id->length, hash_key); | |
92 | ||
93 | return (unsigned long) u; | |
94 | } | |
95 | ||
96 | int client_id_compare_func(const void *_a, const void *_b) { | |
97 | const DHCPClientId *a, *b; | |
98 | ||
99 | a = _a; | |
100 | b = _b; | |
101 | ||
102 | assert(!a->length || a->data); | |
103 | assert(!b->length || b->data); | |
104 | ||
105 | if (a->length != b->length) | |
106 | return a->length < b->length ? -1 : 1; | |
107 | ||
108 | return memcmp(a->data, b->data, a->length); | |
109 | } | |
110 | ||
d5099efc MS |
111 | static const struct hash_ops client_id_hash_ops = { |
112 | .hash = client_id_hash_func, | |
113 | .compare = client_id_compare_func | |
114 | }; | |
115 | ||
87322b3a TG |
116 | static void dhcp_lease_free(DHCPLease *lease) { |
117 | if (!lease) | |
118 | return; | |
119 | ||
120 | free(lease->client_id.data); | |
121 | free(lease); | |
122 | } | |
123 | ||
b44cd882 | 124 | sd_dhcp_server *sd_dhcp_server_unref(sd_dhcp_server *server) { |
3bdace9b | 125 | DHCPLease *lease; |
87322b3a | 126 | |
3bdace9b LP |
127 | if (!server) |
128 | return NULL; | |
b44cd882 | 129 | |
3bdace9b LP |
130 | if (REFCNT_DEC(server->n_ref) > 0) |
131 | return NULL; | |
ff734080 | 132 | |
3bdace9b | 133 | log_dhcp_server(server, "UNREF"); |
87322b3a | 134 | |
3bdace9b | 135 | sd_dhcp_server_stop(server); |
87322b3a | 136 | |
3bdace9b LP |
137 | sd_event_unref(server->event); |
138 | ||
8eb9058d LP |
139 | free(server->timezone); |
140 | ||
3bdace9b LP |
141 | while ((lease = hashmap_steal_first(server->leases_by_client_id))) |
142 | dhcp_lease_free(lease); | |
143 | hashmap_free(server->leases_by_client_id); | |
144 | ||
145 | free(server->bound_leases); | |
146 | free(server); | |
b44cd882 TG |
147 | |
148 | return NULL; | |
149 | } | |
150 | ||
3a864fe4 | 151 | int sd_dhcp_server_new(sd_dhcp_server **ret, int ifindex) { |
b44cd882 TG |
152 | _cleanup_dhcp_server_unref_ sd_dhcp_server *server = NULL; |
153 | ||
154 | assert_return(ret, -EINVAL); | |
3a864fe4 | 155 | assert_return(ifindex > 0, -EINVAL); |
b44cd882 TG |
156 | |
157 | server = new0(sd_dhcp_server, 1); | |
158 | if (!server) | |
159 | return -ENOMEM; | |
160 | ||
161 | server->n_ref = REFCNT_INIT; | |
8de4a226 | 162 | server->fd_raw = -1; |
ff734080 | 163 | server->fd = -1; |
20af7091 | 164 | server->address = htobe32(INADDR_ANY); |
59b8f6b6 | 165 | server->netmask = htobe32(INADDR_ANY); |
3a864fe4 | 166 | server->index = ifindex; |
d5099efc | 167 | server->leases_by_client_id = hashmap_new(&client_id_hash_ops); |
b44cd882 TG |
168 | |
169 | *ret = server; | |
170 | server = NULL; | |
171 | ||
172 | return 0; | |
173 | } | |
174 | ||
a6f1e036 TG |
175 | int sd_dhcp_server_attach_event(sd_dhcp_server *server, sd_event *event, |
176 | int priority) { | |
b44cd882 TG |
177 | int r; |
178 | ||
179 | assert_return(server, -EINVAL); | |
180 | assert_return(!server->event, -EBUSY); | |
181 | ||
182 | if (event) | |
183 | server->event = sd_event_ref(event); | |
184 | else { | |
185 | r = sd_event_default(&server->event); | |
186 | if (r < 0) | |
187 | return r; | |
188 | } | |
189 | ||
190 | server->event_priority = priority; | |
191 | ||
192 | return 0; | |
193 | } | |
194 | ||
195 | int sd_dhcp_server_detach_event(sd_dhcp_server *server) { | |
196 | assert_return(server, -EINVAL); | |
197 | ||
198 | server->event = sd_event_unref(server->event); | |
199 | ||
200 | return 0; | |
201 | } | |
202 | ||
203 | sd_event *sd_dhcp_server_get_event(sd_dhcp_server *server) { | |
204 | assert_return(server, NULL); | |
205 | ||
206 | return server->event; | |
207 | } | |
ff734080 TG |
208 | |
209 | int sd_dhcp_server_stop(sd_dhcp_server *server) { | |
210 | assert_return(server, -EINVAL); | |
211 | ||
212 | server->receive_message = | |
213 | sd_event_source_unref(server->receive_message); | |
214 | ||
8de4a226 | 215 | server->fd_raw = safe_close(server->fd_raw); |
ff734080 TG |
216 | server->fd = safe_close(server->fd); |
217 | ||
218 | log_dhcp_server(server, "STOPPED"); | |
219 | ||
220 | return 0; | |
221 | } | |
222 | ||
a6f1e036 TG |
223 | static int dhcp_server_send_unicast_raw(sd_dhcp_server *server, |
224 | DHCPPacket *packet, size_t len) { | |
969b009d TG |
225 | union sockaddr_union link = { |
226 | .ll.sll_family = AF_PACKET, | |
227 | .ll.sll_protocol = htons(ETH_P_IP), | |
228 | .ll.sll_ifindex = server->index, | |
229 | .ll.sll_halen = ETH_ALEN, | |
230 | }; | |
231 | int r; | |
232 | ||
233 | assert(server); | |
234 | assert(server->index > 0); | |
235 | assert(server->address); | |
236 | assert(packet); | |
237 | assert(len > sizeof(DHCPPacket)); | |
238 | ||
239 | memcpy(&link.ll.sll_addr, &packet->dhcp.chaddr, ETH_ALEN); | |
240 | ||
241 | dhcp_packet_append_ip_headers(packet, server->address, DHCP_PORT_SERVER, | |
a6f1e036 TG |
242 | packet->dhcp.yiaddr, |
243 | DHCP_PORT_CLIENT, len); | |
969b009d TG |
244 | |
245 | r = dhcp_network_send_raw_socket(server->fd_raw, &link, packet, len); | |
246 | if (r < 0) | |
247 | return r; | |
248 | ||
249 | return 0; | |
250 | } | |
251 | ||
252 | static int dhcp_server_send_udp(sd_dhcp_server *server, be32_t destination, | |
253 | DHCPMessage *message, size_t len) { | |
254 | union sockaddr_union dest = { | |
255 | .in.sin_family = AF_INET, | |
256 | .in.sin_port = htobe16(DHCP_PORT_CLIENT), | |
257 | .in.sin_addr.s_addr = destination, | |
258 | }; | |
259 | struct iovec iov = { | |
260 | .iov_base = message, | |
261 | .iov_len = len, | |
262 | }; | |
263 | uint8_t cmsgbuf[CMSG_LEN(sizeof(struct in_pktinfo))] = {}; | |
264 | struct msghdr msg = { | |
265 | .msg_name = &dest, | |
266 | .msg_namelen = sizeof(dest.in), | |
267 | .msg_iov = &iov, | |
268 | .msg_iovlen = 1, | |
269 | .msg_control = cmsgbuf, | |
270 | .msg_controllen = sizeof(cmsgbuf), | |
271 | }; | |
272 | struct cmsghdr *cmsg; | |
273 | struct in_pktinfo *pktinfo; | |
274 | int r; | |
275 | ||
276 | assert(server); | |
277 | assert(server->fd > 0); | |
278 | assert(message); | |
279 | assert(len > sizeof(DHCPMessage)); | |
280 | ||
281 | cmsg = CMSG_FIRSTHDR(&msg); | |
282 | assert(cmsg); | |
283 | ||
284 | cmsg->cmsg_level = IPPROTO_IP; | |
285 | cmsg->cmsg_type = IP_PKTINFO; | |
286 | cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); | |
287 | ||
288 | /* we attach source interface and address info to the message | |
289 | rather than binding the socket. This will be mostly useful | |
290 | when we gain support for arbitrary number of server addresses | |
291 | */ | |
292 | pktinfo = (struct in_pktinfo*) CMSG_DATA(cmsg); | |
293 | assert(pktinfo); | |
294 | ||
295 | pktinfo->ipi_ifindex = server->index; | |
296 | pktinfo->ipi_spec_dst.s_addr = server->address; | |
297 | ||
298 | r = sendmsg(server->fd, &msg, 0); | |
299 | if (r < 0) | |
300 | return -errno; | |
301 | ||
302 | return 0; | |
303 | } | |
304 | ||
305 | static bool requested_broadcast(DHCPRequest *req) { | |
306 | assert(req); | |
307 | ||
308 | return req->message->flags & htobe16(0x8000); | |
309 | } | |
310 | ||
311 | int dhcp_server_send_packet(sd_dhcp_server *server, | |
312 | DHCPRequest *req, DHCPPacket *packet, | |
313 | int type, size_t optoffset) { | |
314 | be32_t destination = INADDR_ANY; | |
315 | int r; | |
316 | ||
317 | assert(server); | |
318 | assert(req); | |
319 | assert(req->max_optlen); | |
320 | assert(optoffset <= req->max_optlen); | |
321 | assert(packet); | |
322 | ||
323 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &optoffset, 0, | |
324 | DHCP_OPTION_SERVER_IDENTIFIER, | |
325 | 4, &server->address); | |
326 | if (r < 0) | |
327 | return r; | |
328 | ||
329 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &optoffset, 0, | |
330 | DHCP_OPTION_END, 0, NULL); | |
331 | if (r < 0) | |
332 | return r; | |
333 | ||
334 | /* RFC 2131 Section 4.1 | |
335 | ||
336 | If the ’giaddr’ field in a DHCP message from a client is non-zero, | |
337 | the server sends any return messages to the ’DHCP server’ port on the | |
338 | BOOTP relay agent whose address appears in ’giaddr’. If the ’giaddr’ | |
339 | field is zero and the ’ciaddr’ field is nonzero, then the server | |
340 | unicasts DHCPOFFER and DHCPACK messages to the address in ’ciaddr’. | |
341 | If ’giaddr’ is zero and ’ciaddr’ is zero, and the broadcast bit is | |
342 | set, then the server broadcasts DHCPOFFER and DHCPACK messages to | |
343 | 0xffffffff. If the broadcast bit is not set and ’giaddr’ is zero and | |
344 | ’ciaddr’ is zero, then the server unicasts DHCPOFFER and DHCPACK | |
345 | messages to the client’s hardware address and ’yiaddr’ address. In | |
346 | all cases, when ’giaddr’ is zero, the server broadcasts any DHCPNAK | |
347 | messages to 0xffffffff. | |
348 | ||
349 | Section 4.3.2 | |
350 | ||
351 | If ’giaddr’ is set in the DHCPREQUEST message, the client is on a | |
352 | different subnet. The server MUST set the broadcast bit in the | |
353 | DHCPNAK, so that the relay agent will broadcast the DHCPNAK to the | |
354 | client, because the client may not have a correct network address | |
355 | or subnet mask, and the client may not be answering ARP requests. | |
356 | */ | |
357 | if (req->message->giaddr) { | |
358 | destination = req->message->giaddr; | |
359 | if (type == DHCP_NAK) | |
360 | packet->dhcp.flags = htobe16(0x8000); | |
361 | } else if (req->message->ciaddr && type != DHCP_NAK) | |
362 | destination = req->message->ciaddr; | |
363 | ||
d6bd972d | 364 | if (destination != INADDR_ANY) |
969b009d TG |
365 | return dhcp_server_send_udp(server, destination, &packet->dhcp, |
366 | sizeof(DHCPMessage) + optoffset); | |
d6bd972d | 367 | else if (requested_broadcast(req) || type == DHCP_NAK) |
a6f1e036 TG |
368 | return dhcp_server_send_udp(server, INADDR_BROADCAST, |
369 | &packet->dhcp, | |
d6bd972d | 370 | sizeof(DHCPMessage) + optoffset); |
969b009d | 371 | else |
a6f1e036 TG |
372 | /* we cannot send UDP packet to specific MAC address when the |
373 | address is not yet configured, so must fall back to raw | |
374 | packets */ | |
969b009d TG |
375 | return dhcp_server_send_unicast_raw(server, packet, |
376 | sizeof(DHCPPacket) + optoffset); | |
377 | } | |
378 | ||
4dc35568 | 379 | static int server_message_init(sd_dhcp_server *server, DHCPPacket **ret, |
a6f1e036 TG |
380 | uint8_t type, size_t *_optoffset, |
381 | DHCPRequest *req) { | |
4dc35568 | 382 | _cleanup_free_ DHCPPacket *packet = NULL; |
1231c4d2 | 383 | size_t optoffset = 0; |
4dc35568 TG |
384 | int r; |
385 | ||
386 | assert(server); | |
387 | assert(ret); | |
388 | assert(_optoffset); | |
bd57b450 | 389 | assert(IN_SET(type, DHCP_OFFER, DHCP_ACK, DHCP_NAK)); |
4dc35568 TG |
390 | |
391 | packet = malloc0(sizeof(DHCPPacket) + req->max_optlen); | |
392 | if (!packet) | |
393 | return -ENOMEM; | |
394 | ||
a6f1e036 | 395 | r = dhcp_message_init(&packet->dhcp, BOOTREPLY, |
76253e73 DW |
396 | be32toh(req->message->xid), type, ARPHRD_ETHER, |
397 | req->max_optlen, &optoffset); | |
4dc35568 TG |
398 | if (r < 0) |
399 | return r; | |
400 | ||
401 | packet->dhcp.flags = req->message->flags; | |
402 | packet->dhcp.giaddr = req->message->giaddr; | |
403 | memcpy(&packet->dhcp.chaddr, &req->message->chaddr, ETH_ALEN); | |
404 | ||
405 | *_optoffset = optoffset; | |
406 | *ret = packet; | |
407 | packet = NULL; | |
408 | ||
409 | return 0; | |
410 | } | |
411 | ||
a6f1e036 TG |
412 | static int server_send_offer(sd_dhcp_server *server, DHCPRequest *req, |
413 | be32_t address) { | |
4dc35568 TG |
414 | _cleanup_free_ DHCPPacket *packet = NULL; |
415 | size_t offset; | |
416 | be32_t lease_time; | |
417 | int r; | |
418 | ||
419 | r = server_message_init(server, &packet, DHCP_OFFER, &offset, req); | |
420 | if (r < 0) | |
421 | return r; | |
422 | ||
2dead812 | 423 | packet->dhcp.yiaddr = address; |
4dc35568 | 424 | |
c7d9ffe6 | 425 | lease_time = htobe32(req->lifetime); |
4dc35568 | 426 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, |
a6f1e036 TG |
427 | DHCP_OPTION_IP_ADDRESS_LEASE_TIME, 4, |
428 | &lease_time); | |
4dc35568 TG |
429 | if (r < 0) |
430 | return r; | |
431 | ||
59b8f6b6 TG |
432 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, |
433 | DHCP_OPTION_SUBNET_MASK, 4, &server->netmask); | |
434 | if (r < 0) | |
435 | return r; | |
436 | ||
437 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, | |
438 | DHCP_OPTION_ROUTER, 4, &server->address); | |
439 | if (r < 0) | |
440 | return r; | |
441 | ||
4dc35568 TG |
442 | r = dhcp_server_send_packet(server, req, packet, DHCP_OFFER, offset); |
443 | if (r < 0) | |
444 | return r; | |
445 | ||
446 | return 0; | |
447 | } | |
448 | ||
a6f1e036 TG |
449 | static int server_send_ack(sd_dhcp_server *server, DHCPRequest *req, |
450 | be32_t address) { | |
2dead812 TG |
451 | _cleanup_free_ DHCPPacket *packet = NULL; |
452 | size_t offset; | |
453 | be32_t lease_time; | |
454 | int r; | |
455 | ||
456 | r = server_message_init(server, &packet, DHCP_ACK, &offset, req); | |
457 | if (r < 0) | |
458 | return r; | |
459 | ||
460 | packet->dhcp.yiaddr = address; | |
461 | ||
c7d9ffe6 | 462 | lease_time = htobe32(req->lifetime); |
2dead812 | 463 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, |
a6f1e036 TG |
464 | DHCP_OPTION_IP_ADDRESS_LEASE_TIME, 4, |
465 | &lease_time); | |
2dead812 TG |
466 | if (r < 0) |
467 | return r; | |
468 | ||
59b8f6b6 TG |
469 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, |
470 | DHCP_OPTION_SUBNET_MASK, 4, &server->netmask); | |
471 | if (r < 0) | |
472 | return r; | |
473 | ||
474 | r = dhcp_option_append(&packet->dhcp, req->max_optlen, &offset, 0, | |
475 | DHCP_OPTION_ROUTER, 4, &server->address); | |
476 | if (r < 0) | |
477 | return r; | |
478 | ||
8eb9058d LP |
479 | if (server->timezone) { |
480 | r = dhcp_option_append( | |
481 | &packet->dhcp, req->max_optlen, &offset, 0, | |
482 | DHCP_OPTION_NEW_TZDB_TIMEZONE, | |
483 | strlen(server->timezone), server->timezone); | |
484 | if (r < 0) | |
485 | return r; | |
486 | } | |
487 | ||
2dead812 TG |
488 | r = dhcp_server_send_packet(server, req, packet, DHCP_ACK, offset); |
489 | if (r < 0) | |
490 | return r; | |
491 | ||
492 | return 0; | |
493 | } | |
494 | ||
bd57b450 TG |
495 | static int server_send_nak(sd_dhcp_server *server, DHCPRequest *req) { |
496 | _cleanup_free_ DHCPPacket *packet = NULL; | |
497 | size_t offset; | |
498 | int r; | |
499 | ||
500 | r = server_message_init(server, &packet, DHCP_NAK, &offset, req); | |
501 | if (r < 0) | |
502 | return r; | |
503 | ||
504 | r = dhcp_server_send_packet(server, req, packet, DHCP_NAK, offset); | |
505 | if (r < 0) | |
506 | return r; | |
507 | ||
508 | return 0; | |
509 | } | |
510 | ||
a6f1e036 TG |
511 | static int server_send_forcerenew(sd_dhcp_server *server, be32_t address, |
512 | be32_t gateway, uint8_t chaddr[]) { | |
52750344 TG |
513 | _cleanup_free_ DHCPPacket *packet = NULL; |
514 | size_t optoffset = 0; | |
515 | int r; | |
516 | ||
517 | assert(server); | |
518 | assert(address != INADDR_ANY); | |
519 | assert(chaddr); | |
520 | ||
521 | packet = malloc0(sizeof(DHCPPacket) + DHCP_MIN_OPTIONS_SIZE); | |
522 | if (!packet) | |
523 | return -ENOMEM; | |
524 | ||
525 | r = dhcp_message_init(&packet->dhcp, BOOTREPLY, 0, | |
76253e73 DW |
526 | DHCP_FORCERENEW, ARPHRD_ETHER, |
527 | DHCP_MIN_OPTIONS_SIZE, &optoffset); | |
52750344 TG |
528 | if (r < 0) |
529 | return r; | |
530 | ||
531 | r = dhcp_option_append(&packet->dhcp, DHCP_MIN_OPTIONS_SIZE, | |
532 | &optoffset, 0, DHCP_OPTION_END, 0, NULL); | |
533 | if (r < 0) | |
534 | return r; | |
535 | ||
536 | memcpy(&packet->dhcp.chaddr, chaddr, ETH_ALEN); | |
537 | ||
538 | r = dhcp_server_send_udp(server, address, &packet->dhcp, | |
539 | sizeof(DHCPMessage) + optoffset); | |
c15fb62a TA |
540 | if (r < 0) |
541 | return r; | |
52750344 TG |
542 | |
543 | return 0; | |
544 | } | |
545 | ||
816e2e7a TG |
546 | static int parse_request(uint8_t code, uint8_t len, const uint8_t *option, |
547 | void *user_data) { | |
548 | DHCPRequest *req = user_data; | |
549 | ||
550 | assert(req); | |
551 | ||
552 | switch(code) { | |
c7d9ffe6 TG |
553 | case DHCP_OPTION_IP_ADDRESS_LEASE_TIME: |
554 | if (len == 4) | |
555 | req->lifetime = be32toh(*(be32_t*)option); | |
556 | ||
557 | break; | |
2dead812 TG |
558 | case DHCP_OPTION_REQUESTED_IP_ADDRESS: |
559 | if (len == 4) | |
560 | req->requested_ip = *(be32_t*)option; | |
561 | ||
562 | break; | |
816e2e7a TG |
563 | case DHCP_OPTION_SERVER_IDENTIFIER: |
564 | if (len == 4) | |
565 | req->server_id = *(be32_t*)option; | |
566 | ||
567 | break; | |
568 | case DHCP_OPTION_CLIENT_IDENTIFIER: | |
569 | if (len >= 2) { | |
570 | uint8_t *data; | |
571 | ||
572 | data = memdup(option, len); | |
573 | if (!data) | |
574 | return -ENOMEM; | |
575 | ||
576 | free(req->client_id.data); | |
577 | req->client_id.data = data; | |
578 | req->client_id.length = len; | |
579 | } | |
580 | ||
581 | break; | |
582 | case DHCP_OPTION_MAXIMUM_MESSAGE_SIZE: | |
583 | if (len == 2) | |
584 | req->max_optlen = be16toh(*(be16_t*)option) - | |
585 | - sizeof(DHCPPacket); | |
586 | ||
587 | break; | |
588 | } | |
589 | ||
590 | return 0; | |
591 | } | |
592 | ||
593 | static void dhcp_request_free(DHCPRequest *req) { | |
594 | if (!req) | |
595 | return; | |
596 | ||
597 | free(req->client_id.data); | |
598 | free(req); | |
599 | } | |
600 | ||
601 | DEFINE_TRIVIAL_CLEANUP_FUNC(DHCPRequest*, dhcp_request_free); | |
602 | #define _cleanup_dhcp_request_free_ _cleanup_(dhcp_request_freep) | |
603 | ||
604 | static int ensure_sane_request(DHCPRequest *req, DHCPMessage *message) { | |
605 | assert(req); | |
606 | assert(message); | |
607 | ||
608 | req->message = message; | |
609 | ||
e2acdb6b | 610 | /* set client id based on MAC address if client did not send an explicit |
a6f1e036 | 611 | one */ |
816e2e7a TG |
612 | if (!req->client_id.data) { |
613 | uint8_t *data; | |
614 | ||
615 | data = new0(uint8_t, ETH_ALEN + 1); | |
616 | if (!data) | |
617 | return -ENOMEM; | |
618 | ||
619 | req->client_id.length = ETH_ALEN + 1; | |
620 | req->client_id.data = data; | |
621 | req->client_id.data[0] = 0x01; | |
622 | memcpy(&req->client_id.data[1], &message->chaddr, ETH_ALEN); | |
623 | } | |
624 | ||
625 | if (req->max_optlen < DHCP_MIN_OPTIONS_SIZE) | |
626 | req->max_optlen = DHCP_MIN_OPTIONS_SIZE; | |
627 | ||
c7d9ffe6 TG |
628 | if (!req->lifetime) |
629 | req->lifetime = DHCP_DEFAULT_LEASE_TIME; | |
630 | ||
816e2e7a TG |
631 | return 0; |
632 | } | |
633 | ||
87322b3a TG |
634 | static int get_pool_offset(sd_dhcp_server *server, be32_t requested_ip) { |
635 | assert(server); | |
636 | ||
637 | if (!server->pool_size) | |
638 | return -EINVAL; | |
639 | ||
640 | if (be32toh(requested_ip) < be32toh(server->pool_start) || | |
641 | be32toh(requested_ip) >= be32toh(server->pool_start) + | |
500792d8 | 642 | + server->pool_size) |
87322b3a TG |
643 | return -EINVAL; |
644 | ||
645 | return be32toh(requested_ip) - be32toh(server->pool_start); | |
646 | } | |
647 | ||
be077570 TG |
648 | int dhcp_server_handle_message(sd_dhcp_server *server, DHCPMessage *message, |
649 | size_t length) { | |
816e2e7a | 650 | _cleanup_dhcp_request_free_ DHCPRequest *req = NULL; |
87322b3a | 651 | DHCPLease *existing_lease; |
816e2e7a | 652 | int type, r; |
be077570 TG |
653 | |
654 | assert(server); | |
655 | assert(message); | |
656 | ||
657 | if (message->op != BOOTREQUEST || | |
658 | message->htype != ARPHRD_ETHER || | |
659 | message->hlen != ETHER_ADDR_LEN) | |
660 | return 0; | |
661 | ||
816e2e7a TG |
662 | req = new0(DHCPRequest, 1); |
663 | if (!req) | |
664 | return -ENOMEM; | |
665 | ||
666 | type = dhcp_option_parse(message, length, parse_request, req); | |
be077570 TG |
667 | if (type < 0) |
668 | return 0; | |
669 | ||
816e2e7a TG |
670 | r = ensure_sane_request(req, message); |
671 | if (r < 0) | |
672 | /* this only fails on critical errors */ | |
673 | return r; | |
674 | ||
a6f1e036 TG |
675 | existing_lease = hashmap_get(server->leases_by_client_id, |
676 | &req->client_id); | |
87322b3a | 677 | |
4dc35568 TG |
678 | switch(type) { |
679 | case DHCP_DISCOVER: | |
2dead812 | 680 | { |
87322b3a TG |
681 | be32_t address = INADDR_ANY; |
682 | unsigned i; | |
2dead812 | 683 | |
4dc35568 TG |
684 | log_dhcp_server(server, "DISCOVER (0x%x)", |
685 | be32toh(req->message->xid)); | |
686 | ||
2dead812 TG |
687 | if (!server->pool_size) |
688 | /* no pool allocated */ | |
689 | return 0; | |
690 | ||
87322b3a TG |
691 | /* for now pick a random free address from the pool */ |
692 | if (existing_lease) | |
693 | address = existing_lease->address; | |
694 | else { | |
695 | for (i = 0; i < server->pool_size; i++) { | |
696 | if (!server->bound_leases[server->next_offer]) { | |
697 | address = htobe32(be32toh(server->pool_start) + server->next_offer); | |
698 | break; | |
699 | } else | |
700 | server->next_offer = (server->next_offer + 1) % server->pool_size; | |
701 | } | |
702 | } | |
703 | ||
704 | if (address == INADDR_ANY) | |
705 | /* no free addresses left */ | |
706 | return 0; | |
2dead812 TG |
707 | |
708 | r = server_send_offer(server, req, address); | |
4dc35568 TG |
709 | if (r < 0) { |
710 | /* this only fails on critical errors */ | |
711 | log_dhcp_server(server, "could not send offer: %s", | |
712 | strerror(-r)); | |
713 | return r; | |
714 | } else { | |
715 | log_dhcp_server(server, "OFFER (0x%x)", | |
716 | be32toh(req->message->xid)); | |
717 | return DHCP_OFFER; | |
718 | } | |
be077570 | 719 | |
4dc35568 TG |
720 | break; |
721 | } | |
5b34277c TG |
722 | case DHCP_DECLINE: |
723 | log_dhcp_server(server, "DECLINE (0x%x)", | |
724 | be32toh(req->message->xid)); | |
725 | ||
726 | /* TODO: make sure we don't offer this address again */ | |
727 | ||
728 | return 1; | |
729 | ||
730 | break; | |
2dead812 TG |
731 | case DHCP_REQUEST: |
732 | { | |
733 | be32_t address; | |
bd57b450 | 734 | bool init_reboot = false; |
87322b3a | 735 | int pool_offset; |
2dead812 TG |
736 | |
737 | /* see RFC 2131, section 4.3.2 */ | |
738 | ||
739 | if (req->server_id) { | |
740 | log_dhcp_server(server, "REQUEST (selecting) (0x%x)", | |
741 | be32toh(req->message->xid)); | |
742 | ||
743 | /* SELECTING */ | |
744 | if (req->server_id != server->address) | |
745 | /* client did not pick us */ | |
746 | return 0; | |
747 | ||
748 | if (req->message->ciaddr) | |
749 | /* this MUST be zero */ | |
750 | return 0; | |
751 | ||
752 | if (!req->requested_ip) | |
753 | /* this must be filled in with the yiaddr | |
754 | from the chosen OFFER */ | |
755 | return 0; | |
756 | ||
757 | address = req->requested_ip; | |
758 | } else if (req->requested_ip) { | |
759 | log_dhcp_server(server, "REQUEST (init-reboot) (0x%x)", | |
760 | be32toh(req->message->xid)); | |
761 | ||
762 | /* INIT-REBOOT */ | |
763 | if (req->message->ciaddr) | |
764 | /* this MUST be zero */ | |
765 | return 0; | |
766 | ||
bd57b450 | 767 | /* TODO: check more carefully if IP is correct */ |
2dead812 | 768 | address = req->requested_ip; |
bd57b450 | 769 | init_reboot = true; |
2dead812 TG |
770 | } else { |
771 | log_dhcp_server(server, "REQUEST (rebinding/renewing) (0x%x)", | |
772 | be32toh(req->message->xid)); | |
773 | ||
774 | /* REBINDING / RENEWING */ | |
775 | if (!req->message->ciaddr) | |
776 | /* this MUST be filled in with clients IP address */ | |
777 | return 0; | |
778 | ||
779 | address = req->message->ciaddr; | |
780 | } | |
781 | ||
87322b3a TG |
782 | pool_offset = get_pool_offset(server, address); |
783 | ||
784 | /* verify that the requested address is from the pool, and either | |
785 | owned by the current client or free */ | |
786 | if (pool_offset >= 0 && | |
787 | server->bound_leases[pool_offset] == existing_lease) { | |
788 | DHCPLease *lease; | |
a7f7d1bd | 789 | usec_t time_now = 0; |
87322b3a TG |
790 | |
791 | if (!existing_lease) { | |
792 | lease = new0(DHCPLease, 1); | |
793 | lease->address = req->requested_ip; | |
794 | lease->client_id.data = memdup(req->client_id.data, | |
795 | req->client_id.length); | |
02557f97 TA |
796 | if (!lease->client_id.data) { |
797 | free(lease); | |
87322b3a | 798 | return -ENOMEM; |
02557f97 | 799 | } |
87322b3a | 800 | lease->client_id.length = req->client_id.length; |
a6f1e036 TG |
801 | memcpy(&lease->chaddr, &req->message->chaddr, |
802 | ETH_ALEN); | |
52750344 | 803 | lease->gateway = req->message->giaddr; |
87322b3a TG |
804 | } else |
805 | lease = existing_lease; | |
806 | ||
a6f1e036 TG |
807 | r = sd_event_now(server->event, |
808 | clock_boottime_or_monotonic(), | |
809 | &time_now); | |
bff92d2c SS |
810 | if (r < 0) { |
811 | if (!existing_lease) | |
812 | dhcp_lease_free(lease); | |
38a03f06 | 813 | return r; |
bff92d2c SS |
814 | } |
815 | ||
87322b3a TG |
816 | lease->expiration = req->lifetime * USEC_PER_SEC + time_now; |
817 | ||
2dead812 TG |
818 | r = server_send_ack(server, req, address); |
819 | if (r < 0) { | |
820 | /* this only fails on critical errors */ | |
821 | log_dhcp_server(server, "could not send ack: %s", | |
822 | strerror(-r)); | |
87322b3a TG |
823 | |
824 | if (!existing_lease) | |
825 | dhcp_lease_free(lease); | |
826 | ||
2dead812 TG |
827 | return r; |
828 | } else { | |
829 | log_dhcp_server(server, "ACK (0x%x)", | |
830 | be32toh(req->message->xid)); | |
87322b3a TG |
831 | |
832 | server->bound_leases[pool_offset] = lease; | |
a6f1e036 TG |
833 | hashmap_put(server->leases_by_client_id, |
834 | &lease->client_id, lease); | |
87322b3a | 835 | |
2dead812 TG |
836 | return DHCP_ACK; |
837 | } | |
bd57b450 TG |
838 | } else if (init_reboot) { |
839 | r = server_send_nak(server, req); | |
840 | if (r < 0) { | |
841 | /* this only fails on critical errors */ | |
842 | log_dhcp_server(server, "could not send nak: %s", | |
843 | strerror(-r)); | |
844 | return r; | |
845 | } else { | |
846 | log_dhcp_server(server, "NAK (0x%x)", | |
847 | be32toh(req->message->xid)); | |
848 | return DHCP_NAK; | |
849 | } | |
850 | } | |
2dead812 TG |
851 | |
852 | break; | |
853 | } | |
500792d8 TG |
854 | case DHCP_RELEASE: { |
855 | int pool_offset; | |
856 | ||
857 | log_dhcp_server(server, "RELEASE (0x%x)", | |
858 | be32toh(req->message->xid)); | |
859 | ||
860 | if (!existing_lease) | |
861 | return 0; | |
862 | ||
863 | if (existing_lease->address != req->message->ciaddr) | |
864 | return 0; | |
865 | ||
866 | pool_offset = get_pool_offset(server, req->message->ciaddr); | |
867 | if (pool_offset < 0) | |
868 | return 0; | |
869 | ||
870 | if (server->bound_leases[pool_offset] == existing_lease) { | |
871 | server->bound_leases[pool_offset] = NULL; | |
872 | hashmap_remove(server->leases_by_client_id, existing_lease); | |
873 | dhcp_lease_free(existing_lease); | |
874 | ||
875 | return 1; | |
876 | } else | |
877 | return 0; | |
878 | } | |
2dead812 | 879 | } |
4dc35568 TG |
880 | |
881 | return 0; | |
be077570 TG |
882 | } |
883 | ||
ff734080 TG |
884 | static int server_receive_message(sd_event_source *s, int fd, |
885 | uint32_t revents, void *userdata) { | |
be077570 | 886 | _cleanup_free_ DHCPMessage *message = NULL; |
3a864fe4 | 887 | uint8_t cmsgbuf[CMSG_LEN(sizeof(struct in_pktinfo))]; |
ff734080 TG |
888 | sd_dhcp_server *server = userdata; |
889 | struct iovec iov = {}; | |
890 | struct msghdr msg = { | |
891 | .msg_iov = &iov, | |
892 | .msg_iovlen = 1, | |
3a864fe4 TG |
893 | .msg_control = cmsgbuf, |
894 | .msg_controllen = sizeof(cmsgbuf), | |
ff734080 | 895 | }; |
3a864fe4 | 896 | struct cmsghdr *cmsg; |
ff734080 TG |
897 | int buflen = 0, len, r; |
898 | ||
899 | assert(server); | |
900 | ||
901 | r = ioctl(fd, FIONREAD, &buflen); | |
902 | if (r < 0) | |
903 | return r; | |
904 | if (buflen < 0) | |
905 | return -EIO; | |
906 | ||
907 | message = malloc0(buflen); | |
908 | if (!message) | |
909 | return -ENOMEM; | |
910 | ||
911 | iov.iov_base = message; | |
912 | iov.iov_len = buflen; | |
913 | ||
a38d9945 | 914 | len = recvmsg(fd, &msg, 0); |
ff734080 TG |
915 | if (len < buflen) |
916 | return 0; | |
be077570 TG |
917 | else if ((size_t)len < sizeof(DHCPMessage)) |
918 | return 0; | |
ff734080 | 919 | |
2a1288ff | 920 | CMSG_FOREACH(cmsg, &msg) { |
3a864fe4 TG |
921 | if (cmsg->cmsg_level == IPPROTO_IP && |
922 | cmsg->cmsg_type == IP_PKTINFO && | |
923 | cmsg->cmsg_len == CMSG_LEN(sizeof(struct in_pktinfo))) { | |
924 | struct in_pktinfo *info = (struct in_pktinfo*)CMSG_DATA(cmsg); | |
925 | ||
a6f1e036 TG |
926 | /* TODO figure out if this can be done as a filter on |
927 | * the socket, like for IPv6 */ | |
3a864fe4 TG |
928 | if (server->index != info->ipi_ifindex) |
929 | return 0; | |
930 | ||
931 | break; | |
932 | } | |
933 | } | |
934 | ||
be077570 | 935 | return dhcp_server_handle_message(server, message, (size_t)len); |
ff734080 TG |
936 | } |
937 | ||
938 | int sd_dhcp_server_start(sd_dhcp_server *server) { | |
939 | int r; | |
940 | ||
941 | assert_return(server, -EINVAL); | |
942 | assert_return(server->event, -EINVAL); | |
943 | assert_return(!server->receive_message, -EBUSY); | |
8de4a226 | 944 | assert_return(server->fd_raw == -1, -EBUSY); |
ff734080 | 945 | assert_return(server->fd == -1, -EBUSY); |
20af7091 | 946 | assert_return(server->address != htobe32(INADDR_ANY), -EUNATCH); |
ff734080 | 947 | |
8de4a226 TG |
948 | r = socket(AF_PACKET, SOCK_DGRAM | SOCK_NONBLOCK, 0); |
949 | if (r < 0) { | |
950 | r = -errno; | |
951 | sd_dhcp_server_stop(server); | |
952 | return r; | |
953 | } | |
954 | server->fd_raw = r; | |
955 | ||
ff734080 TG |
956 | r = dhcp_network_bind_udp_socket(INADDR_ANY, DHCP_PORT_SERVER); |
957 | if (r < 0) { | |
958 | sd_dhcp_server_stop(server); | |
959 | return r; | |
960 | } | |
961 | server->fd = r; | |
962 | ||
963 | r = sd_event_add_io(server->event, &server->receive_message, | |
964 | server->fd, EPOLLIN, | |
965 | server_receive_message, server); | |
966 | if (r < 0) { | |
967 | sd_dhcp_server_stop(server); | |
968 | return r; | |
969 | } | |
970 | ||
971 | r = sd_event_source_set_priority(server->receive_message, | |
972 | server->event_priority); | |
973 | if (r < 0) { | |
974 | sd_dhcp_server_stop(server); | |
975 | return r; | |
976 | } | |
977 | ||
978 | log_dhcp_server(server, "STARTED"); | |
979 | ||
980 | return 0; | |
981 | } | |
52750344 TG |
982 | |
983 | int sd_dhcp_server_forcerenew(sd_dhcp_server *server) { | |
984 | unsigned i; | |
621ac3d2 | 985 | int r = 0; |
52750344 TG |
986 | |
987 | assert_return(server, -EINVAL); | |
988 | assert(server->bound_leases); | |
989 | ||
990 | for (i = 0; i < server->pool_size; i++) { | |
991 | DHCPLease *lease = server->bound_leases[i]; | |
992 | ||
993 | if (!lease) | |
994 | continue; | |
995 | ||
996 | r = server_send_forcerenew(server, lease->address, | |
997 | lease->gateway, | |
998 | lease->chaddr); | |
999 | if (r < 0) | |
1000 | return r; | |
1001 | else | |
1002 | log_dhcp_server(server, "FORCERENEW"); | |
1003 | } | |
1004 | ||
1005 | return r; | |
1006 | } | |
8eb9058d LP |
1007 | |
1008 | int sd_dhcp_server_set_timezone(sd_dhcp_server *server, const char *timezone) { | |
1009 | int r; | |
1010 | ||
1011 | assert_return(server, -EINVAL); | |
1012 | assert_return(timezone_is_valid(timezone), -EINVAL); | |
1013 | ||
1014 | if (streq_ptr(timezone, server->timezone)) | |
1015 | return 0; | |
1016 | ||
1017 | r = free_and_strdup(&server->timezone, timezone); | |
1018 | if (r < 0) | |
1019 | return r; | |
1020 | ||
1021 | return 1; | |
1022 | } |