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