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