1 /**
2 * @file
3 * Dynamic Host Configuration Protocol client
4 *
5 */
6
7 /*
8 *
9 * Copyright (c) 2001-2004 Leon Woestenberg <leon.woestenberg@gmx.net>
10 * Copyright (c) 2001-2004 Axon Digital Design B.V., The Netherlands.
11 * All rights reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without modification,
14 * are permitted provided that the following conditions are met:
15 *
16 * 1. Redistributions of source code must retain the above copyright notice,
17 * this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright notice,
19 * this list of conditions and the following disclaimer in the documentation
20 * and/or other materials provided with the distribution.
21 * 3. The name of the author may not be used to endorse or promote products
22 * derived from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
25 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
27 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
28 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
29 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
32 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
33 * OF SUCH DAMAGE.
34 *
35 * This file is a contribution to the lwIP TCP/IP stack.
36 * The Swedish Institute of Computer Science and Adam Dunkels
37 * are specifically granted permission to redistribute this
38 * source code.
39 *
40 * Author: Leon Woestenberg <leon.woestenberg@gmx.net>
41 *
42 * This is a DHCP client for the lwIP TCP/IP stack. It aims to conform
43 * with RFC 2131 and RFC 2132.
44 *
45 * TODO:
46 * - Proper parsing of DHCP messages exploiting file/sname field overloading.
47 * - Add JavaDoc style documentation (API, internals).
48 * - Support for interfaces other than Ethernet (SLIP, PPP, ...)
49 *
50 * Please coordinate changes and requests with Leon Woestenberg
51 * <leon.woestenberg@gmx.net>
52 *
53 * Integration with your code:
54 *
55 * In lwip/dhcp.h
56 * #define DHCP_COARSE_TIMER_SECS (recommended 60 which is a minute)
57 * #define DHCP_FINE_TIMER_MSECS (recommended 500 which equals TCP coarse timer)
58 *
59 * Then have your application call dhcp_coarse_tmr() and
60 * dhcp_fine_tmr() on the defined intervals.
61 *
62 * dhcp_start(struct netif *netif);
63 * starts a DHCP client instance which configures the interface by
64 * obtaining an IP address lease and maintaining it.
65 *
66 * Use dhcp_release(netif) to end the lease and use dhcp_stop(netif)
67 * to remove the DHCP client.
68 *
69 */
70
71 #include "lwip/opt.h"
72
73 #if LWIP_DHCP /* don't build if not configured for use in lwipopts.h */
74
75 #include "lwip/stats.h"
76 #include "lwip/mem.h"
77 #include "lwip/udp.h"
78 #include "lwip/ip_addr.h"
79 #include "lwip/netif.h"
80 #include "lwip/inet.h"
81 #include "lwip/sys.h"
82 #include "lwip/dhcp.h"
83 #include "lwip/autoip.h"
84 #include "lwip/dns.h"
85 #include "netif/etharp.h"
86
87 #include <string.h>
88
89 /** Default for DHCP_GLOBAL_XID is 0xABCD0000
90 * This can be changed by defining DHCP_GLOBAL_XID and DHCP_GLOBAL_XID_HEADER, e.g.
91 * #define DHCP_GLOBAL_XID_HEADER "stdlib.h"
92 * #define DHCP_GLOBAL_XID rand()
93 */
94 #ifdef DHCP_GLOBAL_XID_HEADER
95 #include DHCP_GLOBAL_XID_HEADER /* include optional starting XID generation prototypes */
96 #endif
97
98 /** DHCP_OPTION_MAX_MSG_SIZE is set to the MTU
99 * MTU is checked to be big enough in dhcp_start */
100 #define DHCP_MAX_MSG_LEN(netif) (netif->mtu)
101 #define DHCP_MAX_MSG_LEN_MIN_REQUIRED 576
102
103 /* DHCP client state machine functions */
104 static void dhcp_handle_ack(struct netif *netif);
105 static void dhcp_handle_nak(struct netif *netif);
106 static void dhcp_handle_offer(struct netif *netif);
107
108 static err_t dhcp_discover(struct netif *netif);
109 static err_t dhcp_select(struct netif *netif);
110 static void dhcp_check(struct netif *netif);
111 static void dhcp_bind(struct netif *netif);
112 #if DHCP_DOES_ARP_CHECK
113 static err_t dhcp_decline(struct netif *netif);
114 #endif /* DHCP_DOES_ARP_CHECK */
115 static err_t dhcp_rebind(struct netif *netif);
116 static void dhcp_set_state(struct dhcp *dhcp, u8_t new_state);
117
118 /* receive, unfold, parse and free incoming messages */
119 static void dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port);
120 static err_t dhcp_unfold_reply(struct dhcp *dhcp);
121 static u8_t *dhcp_get_option_ptr(struct dhcp *dhcp, u8_t option_type);
122 static u8_t dhcp_get_option_byte(u8_t *ptr);
123 #if 0
124 static u16_t dhcp_get_option_short(u8_t *ptr);
125 #endif
126 static u32_t dhcp_get_option_long(u8_t *ptr);
127 static void dhcp_free_reply(struct dhcp *dhcp);
128
129 /* set the DHCP timers */
130 static void dhcp_timeout(struct netif *netif);
131 static void dhcp_t1_timeout(struct netif *netif);
132 static void dhcp_t2_timeout(struct netif *netif);
133
134 /* build outgoing messages */
135 /* create a DHCP request, fill in common headers */
136 static err_t dhcp_create_request(struct netif *netif);
137 /* free a DHCP request */
138 static void dhcp_delete_request(struct netif *netif);
139 /* add a DHCP option (type, then length in bytes) */
140 static void dhcp_option(struct dhcp *dhcp, u8_t option_type, u8_t option_len);
141 /* add option values */
142 static void dhcp_option_byte(struct dhcp *dhcp, u8_t value);
143 static void dhcp_option_short(struct dhcp *dhcp, u16_t value);
144 static void dhcp_option_long(struct dhcp *dhcp, u32_t value);
145 /* always add the DHCP options trailer to end and pad */
146 static void dhcp_option_trailer(struct dhcp *dhcp);
147
148 /**
149 * Back-off the DHCP client (because of a received NAK response).
150 *
151 * Back-off the DHCP client because of a received NAK. Receiving a
152 * NAK means the client asked for something non-sensible, for
153 * example when it tries to renew a lease obtained on another network.
154 *
155 * We clear any existing set IP address and restart DHCP negotiation
156 * afresh (as per RFC2131 3.2.3).
157 *
158 * @param netif the netif under DHCP control
159 */
160 static void
dhcp_handle_nak(struct netif * netif)161 dhcp_handle_nak(struct netif *netif)
162 {
163 struct dhcp *dhcp = netif->dhcp;
164 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_handle_nak(netif=%p) %c%c%"U16_F"\n",
165 (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
166 /* Set the interface down since the address must no longer be used, as per RFC2131 */
167 netif_set_down(netif);
168 /* remove IP address from interface */
169 netif_set_ipaddr(netif, IP_ADDR_ANY);
170 netif_set_gw(netif, IP_ADDR_ANY);
171 netif_set_netmask(netif, IP_ADDR_ANY);
172 /* Change to a defined state */
173 dhcp_set_state(dhcp, DHCP_BACKING_OFF);
174 /* We can immediately restart discovery */
175 dhcp_discover(netif);
176 }
177
178 /**
179 * Checks if the offered IP address is already in use.
180 *
181 * It does so by sending an ARP request for the offered address and
182 * entering CHECKING state. If no ARP reply is received within a small
183 * interval, the address is assumed to be free for use by us.
184 *
185 * @param netif the netif under DHCP control
186 */
187 static void
dhcp_check(struct netif * netif)188 dhcp_check(struct netif *netif)
189 {
190 struct dhcp *dhcp = netif->dhcp;
191 err_t result;
192 u16_t msecs;
193 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_check(netif=%p) %c%c\n", (void *)netif, (s16_t)netif->name[0],
194 (s16_t)netif->name[1]));
195 dhcp_set_state(dhcp, DHCP_CHECKING);
196 /* create an ARP query for the offered IP address, expecting that no host
197 responds, as the IP address should not be in use. */
198 result = etharp_query(netif, &dhcp->offered_ip_addr, NULL);
199 if (result != ERR_OK) {
200 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_check: could not perform ARP query\n"));
201 }
202 dhcp->tries++;
203 msecs = 500;
204 dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
205 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_check(): set request timeout %"U16_F" msecs\n", msecs));
206 }
207
208 /**
209 * Remember the configuration offered by a DHCP server.
210 *
211 * @param netif the netif under DHCP control
212 */
213 static void
dhcp_handle_offer(struct netif * netif)214 dhcp_handle_offer(struct netif *netif)
215 {
216 struct dhcp *dhcp = netif->dhcp;
217 /* obtain the server address */
218 u8_t *option_ptr = dhcp_get_option_ptr(dhcp, DHCP_OPTION_SERVER_ID);
219 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_handle_offer(netif=%p) %c%c%"U16_F"\n",
220 (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
221 if (option_ptr != NULL) {
222 dhcp->server_ip_addr.addr = htonl(dhcp_get_option_long(&option_ptr[2]));
223 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_handle_offer(): server 0x%08"X32_F"\n", dhcp->server_ip_addr.addr));
224 /* remember offered address */
225 ip_addr_set(&dhcp->offered_ip_addr, (struct ip_addr *)&dhcp->msg_in->yiaddr);
226 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_handle_offer(): offer for 0x%08"X32_F"\n", dhcp->offered_ip_addr.addr));
227
228 dhcp_select(netif);
229 }
230 }
231
232 /**
233 * Select a DHCP server offer out of all offers.
234 *
235 * Simply select the first offer received.
236 *
237 * @param netif the netif under DHCP control
238 * @return lwIP specific error (see error.h)
239 */
240 static err_t
dhcp_select(struct netif * netif)241 dhcp_select(struct netif *netif)
242 {
243 struct dhcp *dhcp = netif->dhcp;
244 err_t result;
245 u16_t msecs;
246 #if LWIP_NETIF_HOSTNAME
247 const char *p;
248 #endif /* LWIP_NETIF_HOSTNAME */
249
250 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_select(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
251 dhcp_set_state(dhcp, DHCP_REQUESTING);
252
253 /* create and initialize the DHCP message header */
254 result = dhcp_create_request(netif);
255 if (result == ERR_OK) {
256 dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
257 dhcp_option_byte(dhcp, DHCP_REQUEST);
258
259 dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
260 dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
261
262 /* MUST request the offered IP address */
263 dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
264 dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
265
266 dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
267 dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
268
269 dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 4/*num options*/);
270 dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK);
271 dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER);
272 dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST);
273 dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER);
274
275 #if LWIP_NETIF_HOSTNAME
276 p = (const char*)netif->hostname;
277 if (p != NULL) {
278 dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, strlen(p));
279 while (*p) {
280 dhcp_option_byte(dhcp, *p++);
281 }
282 }
283 #endif /* LWIP_NETIF_HOSTNAME */
284
285 dhcp_option_trailer(dhcp);
286 /* shrink the pbuf to the actual content length */
287 pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
288
289 /* TODO: we really should bind to a specific local interface here
290 but we cannot specify an unconfigured netif as it is addressless */
291 /* send broadcast to any DHCP server */
292 udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
293 /* reconnect to any (or to server here?!) */
294 udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
295 dhcp_delete_request(netif);
296 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_select: REQUESTING\n"));
297 } else {
298 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_select: could not allocate DHCP request\n"));
299 }
300 dhcp->tries++;
301 msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000;
302 dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
303 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_select(): set request timeout %"U16_F" msecs\n", msecs));
304 return result;
305 }
306
307 /**
308 * The DHCP timer that checks for lease renewal/rebind timeouts.
309 *
310 */
311 void
dhcp_coarse_tmr()312 dhcp_coarse_tmr()
313 {
314 struct netif *netif = netif_list;
315 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_coarse_tmr()\n"));
316 /* iterate through all network interfaces */
317 while (netif != NULL) {
318 /* only act on DHCP configured interfaces */
319 if (netif->dhcp != NULL) {
320 /* timer is active (non zero), and triggers (zeroes) now? */
321 if (netif->dhcp->t2_timeout-- == 1) {
322 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_coarse_tmr(): t2 timeout\n"));
323 /* this clients' rebind timeout triggered */
324 dhcp_t2_timeout(netif);
325 /* timer is active (non zero), and triggers (zeroes) now */
326 } else if (netif->dhcp->t1_timeout-- == 1) {
327 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_coarse_tmr(): t1 timeout\n"));
328 /* this clients' renewal timeout triggered */
329 dhcp_t1_timeout(netif);
330 }
331 }
332 /* proceed to next netif */
333 netif = netif->next;
334 }
335 }
336
337 /**
338 * DHCP transaction timeout handling
339 *
340 * A DHCP server is expected to respond within a short period of time.
341 * This timer checks whether an outstanding DHCP request is timed out.
342 *
343 */
344 void
dhcp_fine_tmr()345 dhcp_fine_tmr()
346 {
347 struct netif *netif = netif_list;
348 /* loop through netif's */
349 while (netif != NULL) {
350 /* only act on DHCP configured interfaces */
351 if (netif->dhcp != NULL) {
352 /* timer is active (non zero), and is about to trigger now */
353 if (netif->dhcp->request_timeout > 1) {
354 netif->dhcp->request_timeout--;
355 }
356 else if (netif->dhcp->request_timeout == 1) {
357 netif->dhcp->request_timeout--;
358 /* { netif->dhcp->request_timeout == 0 } */
359 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_fine_tmr(): request timeout\n"));
360 /* this clients' request timeout triggered */
361 dhcp_timeout(netif);
362 }
363 }
364 /* proceed to next network interface */
365 netif = netif->next;
366 }
367 }
368
369 /**
370 * A DHCP negotiation transaction, or ARP request, has timed out.
371 *
372 * The timer that was started with the DHCP or ARP request has
373 * timed out, indicating no response was received in time.
374 *
375 * @param netif the netif under DHCP control
376 */
377 static void
dhcp_timeout(struct netif * netif)378 dhcp_timeout(struct netif *netif)
379 {
380 struct dhcp *dhcp = netif->dhcp;
381 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_timeout()\n"));
382 /* back-off period has passed, or server selection timed out */
383 if ((dhcp->state == DHCP_BACKING_OFF) || (dhcp->state == DHCP_SELECTING)) {
384 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_timeout(): restarting discovery\n"));
385 dhcp_discover(netif);
386 /* receiving the requested lease timed out */
387 } else if (dhcp->state == DHCP_REQUESTING) {
388 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REQUESTING, DHCP request timed out\n"));
389 if (dhcp->tries <= 5) {
390 dhcp_select(netif);
391 } else {
392 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REQUESTING, releasing, restarting\n"));
393 dhcp_release(netif);
394 dhcp_discover(netif);
395 }
396 /* received no ARP reply for the offered address (which is good) */
397 } else if (dhcp->state == DHCP_CHECKING) {
398 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): CHECKING, ARP request timed out\n"));
399 if (dhcp->tries <= 1) {
400 dhcp_check(netif);
401 /* no ARP replies on the offered address,
402 looks like the IP address is indeed free */
403 } else {
404 /* bind the interface to the offered address */
405 dhcp_bind(netif);
406 }
407 }
408 /* did not get response to renew request? */
409 else if (dhcp->state == DHCP_RENEWING) {
410 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): RENEWING, DHCP request timed out\n"));
411 /* just retry renewal */
412 /* note that the rebind timer will eventually time-out if renew does not work */
413 dhcp_renew(netif);
414 /* did not get response to rebind request? */
415 } else if (dhcp->state == DHCP_REBINDING) {
416 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): REBINDING, DHCP request timed out\n"));
417 if (dhcp->tries <= 8) {
418 dhcp_rebind(netif);
419 } else {
420 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_timeout(): RELEASING, DISCOVERING\n"));
421 dhcp_release(netif);
422 dhcp_discover(netif);
423 }
424 }
425 }
426
427 /**
428 * The renewal period has timed out.
429 *
430 * @param netif the netif under DHCP control
431 */
432 static void
dhcp_t1_timeout(struct netif * netif)433 dhcp_t1_timeout(struct netif *netif)
434 {
435 struct dhcp *dhcp = netif->dhcp;
436 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_t1_timeout()\n"));
437 if ((dhcp->state == DHCP_REQUESTING) || (dhcp->state == DHCP_BOUND) || (dhcp->state == DHCP_RENEWING)) {
438 /* just retry to renew - note that the rebind timer (t2) will
439 * eventually time-out if renew tries fail. */
440 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_t1_timeout(): must renew\n"));
441 dhcp_renew(netif);
442 }
443 }
444
445 /**
446 * The rebind period has timed out.
447 *
448 * @param netif the netif under DHCP control
449 */
450 static void
dhcp_t2_timeout(struct netif * netif)451 dhcp_t2_timeout(struct netif *netif)
452 {
453 struct dhcp *dhcp = netif->dhcp;
454 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_t2_timeout()\n"));
455 if ((dhcp->state == DHCP_REQUESTING) || (dhcp->state == DHCP_BOUND) || (dhcp->state == DHCP_RENEWING)) {
456 /* just retry to rebind */
457 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_t2_timeout(): must rebind\n"));
458 dhcp_rebind(netif);
459 }
460 }
461
462 /**
463 * Handle a DHCP ACK packet
464 *
465 * @param netif the netif under DHCP control
466 */
467 static void
dhcp_handle_ack(struct netif * netif)468 dhcp_handle_ack(struct netif *netif)
469 {
470 struct dhcp *dhcp = netif->dhcp;
471 u8_t *option_ptr;
472 /* clear options we might not get from the ACK */
473 dhcp->offered_sn_mask.addr = 0;
474 dhcp->offered_gw_addr.addr = 0;
475 dhcp->offered_bc_addr.addr = 0;
476
477 /* lease time given? */
478 option_ptr = dhcp_get_option_ptr(dhcp, DHCP_OPTION_LEASE_TIME);
479 if (option_ptr != NULL) {
480 /* remember offered lease time */
481 dhcp->offered_t0_lease = dhcp_get_option_long(option_ptr + 2);
482 }
483 /* renewal period given? */
484 option_ptr = dhcp_get_option_ptr(dhcp, DHCP_OPTION_T1);
485 if (option_ptr != NULL) {
486 /* remember given renewal period */
487 dhcp->offered_t1_renew = dhcp_get_option_long(option_ptr + 2);
488 } else {
489 /* calculate safe periods for renewal */
490 dhcp->offered_t1_renew = dhcp->offered_t0_lease / 2;
491 }
492
493 /* renewal period given? */
494 option_ptr = dhcp_get_option_ptr(dhcp, DHCP_OPTION_T2);
495 if (option_ptr != NULL) {
496 /* remember given rebind period */
497 dhcp->offered_t2_rebind = dhcp_get_option_long(option_ptr + 2);
498 } else {
499 /* calculate safe periods for rebinding */
500 dhcp->offered_t2_rebind = dhcp->offered_t0_lease;
501 }
502
503 /* (y)our internet address */
504 ip_addr_set(&dhcp->offered_ip_addr, &dhcp->msg_in->yiaddr);
505
506 /**
507 * Patch #1308
508 * TODO: we must check if the file field is not overloaded by DHCP options!
509 */
510 #if 0
511 /* boot server address */
512 ip_addr_set(&dhcp->offered_si_addr, &dhcp->msg_in->siaddr);
513 /* boot file name */
514 if (dhcp->msg_in->file[0]) {
515 dhcp->boot_file_name = mem_malloc(strlen(dhcp->msg_in->file) + 1);
516 strcpy(dhcp->boot_file_name, dhcp->msg_in->file);
517 }
518 #endif
519
520 /* subnet mask */
521 option_ptr = dhcp_get_option_ptr(dhcp, DHCP_OPTION_SUBNET_MASK);
522 /* subnet mask given? */
523 if (option_ptr != NULL) {
524 dhcp->offered_sn_mask.addr = htonl(dhcp_get_option_long(&option_ptr[2]));
525 }
526
527 /* gateway router */
528 option_ptr = dhcp_get_option_ptr(dhcp, DHCP_OPTION_ROUTER);
529 if (option_ptr != NULL) {
530 dhcp->offered_gw_addr.addr = htonl(dhcp_get_option_long(&option_ptr[2]));
531 }
532
533 /* broadcast address */
534 option_ptr = dhcp_get_option_ptr(dhcp, DHCP_OPTION_BROADCAST);
535 if (option_ptr != NULL) {
536 dhcp->offered_bc_addr.addr = htonl(dhcp_get_option_long(&option_ptr[2]));
537 }
538
539 /* DNS servers */
540 option_ptr = dhcp_get_option_ptr(dhcp, DHCP_OPTION_DNS_SERVER);
541 if (option_ptr != NULL) {
542 u8_t n;
543 dhcp->dns_count = dhcp_get_option_byte(&option_ptr[1]) / (u32_t)sizeof(struct ip_addr);
544 /* limit to at most DHCP_MAX_DNS DNS servers */
545 if (dhcp->dns_count > DHCP_MAX_DNS)
546 dhcp->dns_count = DHCP_MAX_DNS;
547 for (n = 0; n < dhcp->dns_count; n++) {
548 dhcp->offered_dns_addr[n].addr = htonl(dhcp_get_option_long(&option_ptr[2 + n * 4]));
549 #if LWIP_DNS
550 dns_setserver( n, (struct ip_addr *)(&(dhcp->offered_dns_addr[n].addr)));
551 #endif /* LWIP_DNS */
552 }
553 #if LWIP_DNS
554 dns_setserver( n, (struct ip_addr *)(&ip_addr_any));
555 #endif /* LWIP_DNS */
556 }
557 }
558
559 /**
560 * Start DHCP negotiation for a network interface.
561 *
562 * If no DHCP client instance was attached to this interface,
563 * a new client is created first. If a DHCP client instance
564 * was already present, it restarts negotiation.
565 *
566 * @param netif The lwIP network interface
567 * @return lwIP error code
568 * - ERR_OK - No error
569 * - ERR_MEM - Out of memory
570 */
571 err_t
dhcp_start(struct netif * netif)572 dhcp_start(struct netif *netif)
573 {
574 struct dhcp *dhcp;
575 err_t result = ERR_OK;
576
577 LWIP_ERROR("netif != NULL", (netif != NULL), return ERR_ARG;);
578 dhcp = netif->dhcp;
579 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_start(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
580 /* Remove the flag that says this netif is handled by DHCP,
581 it is set when we succeeded starting. */
582 netif->flags &= ~NETIF_FLAG_DHCP;
583
584 /* check MTU of the netif */
585 if (netif->mtu < DHCP_MAX_MSG_LEN_MIN_REQUIRED) {
586 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): Cannot use this netif with DHCP: MTU is too small\n"));
587 return ERR_MEM;
588 }
589
590 /* no DHCP client attached yet? */
591 if (dhcp == NULL) {
592 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting new DHCP client\n"));
593 dhcp = mem_malloc(sizeof(struct dhcp));
594 if (dhcp == NULL) {
595 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): could not allocate dhcp\n"));
596 return ERR_MEM;
597 }
598 /* store this dhcp client in the netif */
599 netif->dhcp = dhcp;
600 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): allocated dhcp"));
601 /* already has DHCP client attached */
602 } else {
603 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 3, ("dhcp_start(): restarting DHCP configuration\n"));
604 if (dhcp->pcb != NULL) {
605 udp_remove(dhcp->pcb);
606 }
607 if (dhcp->p != NULL) {
608 pbuf_free(dhcp->p);
609 }
610 }
611
612 /* clear data structure */
613 memset(dhcp, 0, sizeof(struct dhcp));
614 /* allocate UDP PCB */
615 dhcp->pcb = udp_new();
616 if (dhcp->pcb == NULL) {
617 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): could not obtain pcb\n"));
618 mem_free((void *)dhcp);
619 netif->dhcp = dhcp = NULL;
620 return ERR_MEM;
621 }
622 #if IP_SOF_BROADCAST
623 dhcp->pcb->so_options|=SOF_BROADCAST;
624 #endif /* IP_SOF_BROADCAST */
625 /* set up local and remote port for the pcb */
626 udp_bind(dhcp->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
627 udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
628 /* set up the recv callback and argument */
629 udp_recv(dhcp->pcb, dhcp_recv, netif);
630 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_start(): starting DHCP configuration\n"));
631 /* (re)start the DHCP negotiation */
632 result = dhcp_discover(netif);
633 if (result != ERR_OK) {
634 /* free resources allocated above */
635 dhcp_stop(netif);
636 return ERR_MEM;
637 }
638 /* Set the flag that says this netif is handled by DHCP. */
639 netif->flags |= NETIF_FLAG_DHCP;
640 return result;
641 }
642
643 /**
644 * Inform a DHCP server of our manual configuration.
645 *
646 * This informs DHCP servers of our fixed IP address configuration
647 * by sending an INFORM message. It does not involve DHCP address
648 * configuration, it is just here to be nice to the network.
649 *
650 * @param netif The lwIP network interface
651 */
652 void
dhcp_inform(struct netif * netif)653 dhcp_inform(struct netif *netif)
654 {
655 struct dhcp *dhcp, *old_dhcp = netif->dhcp;
656 err_t result = ERR_OK;
657 dhcp = mem_malloc(sizeof(struct dhcp));
658 if (dhcp == NULL) {
659 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_inform(): could not allocate dhcp\n"));
660 return;
661 }
662 netif->dhcp = dhcp;
663 memset(dhcp, 0, sizeof(struct dhcp));
664
665 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): allocated dhcp\n"));
666 dhcp->pcb = udp_new();
667 if (dhcp->pcb == NULL) {
668 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_inform(): could not obtain pcb"));
669 mem_free((void *)dhcp);
670 return;
671 }
672 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_inform(): created new udp pcb\n"));
673 /* create and initialize the DHCP message header */
674 result = dhcp_create_request(netif);
675 if (result == ERR_OK) {
676
677 dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
678 dhcp_option_byte(dhcp, DHCP_INFORM);
679
680 dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
681 dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
682
683 dhcp_option_trailer(dhcp);
684
685 pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
686
687 #if IP_SOF_BROADCAST
688 dhcp->pcb->so_options|=SOF_BROADCAST;
689 #endif /* IP_SOF_BROADCAST */
690 udp_bind(dhcp->pcb, IP_ADDR_ANY, DHCP_CLIENT_PORT);
691 udp_connect(dhcp->pcb, IP_ADDR_BROADCAST, DHCP_SERVER_PORT);
692 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_inform: INFORMING\n"));
693 udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
694 udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
695 dhcp_delete_request(netif);
696 } else {
697 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_inform: could not allocate DHCP request\n"));
698 }
699
700 if (dhcp->pcb != NULL) {
701 udp_remove(dhcp->pcb);
702 }
703 dhcp->pcb = NULL;
704 mem_free((void *)dhcp);
705 netif->dhcp = old_dhcp;
706 }
707
708 #if DHCP_DOES_ARP_CHECK
709 /**
710 * Match an ARP reply with the offered IP address.
711 *
712 * @param netif the network interface on which the reply was received
713 * @param addr The IP address we received a reply from
714 */
dhcp_arp_reply(struct netif * netif,struct ip_addr * addr)715 void dhcp_arp_reply(struct netif *netif, struct ip_addr *addr)
716 {
717 LWIP_ERROR("netif != NULL", (netif != NULL), return;);
718 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_arp_reply()\n"));
719 /* is a DHCP client doing an ARP check? */
720 if ((netif->dhcp != NULL) && (netif->dhcp->state == DHCP_CHECKING)) {
721 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_arp_reply(): CHECKING, arp reply for 0x%08"X32_F"\n", addr->addr));
722 /* did a host respond with the address we
723 were offered by the DHCP server? */
724 if (ip_addr_cmp(addr, &netif->dhcp->offered_ip_addr)) {
725 /* we will not accept the offered address */
726 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE | 1, ("dhcp_arp_reply(): arp reply matched with offered address, declining\n"));
727 dhcp_decline(netif);
728 }
729 }
730 }
731
732 /**
733 * Decline an offered lease.
734 *
735 * Tell the DHCP server we do not accept the offered address.
736 * One reason to decline the lease is when we find out the address
737 * is already in use by another host (through ARP).
738 *
739 * @param netif the netif under DHCP control
740 */
741 static err_t
dhcp_decline(struct netif * netif)742 dhcp_decline(struct netif *netif)
743 {
744 struct dhcp *dhcp = netif->dhcp;
745 err_t result = ERR_OK;
746 u16_t msecs;
747 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_decline()\n"));
748 dhcp_set_state(dhcp, DHCP_BACKING_OFF);
749 /* create and initialize the DHCP message header */
750 result = dhcp_create_request(netif);
751 if (result == ERR_OK) {
752 dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
753 dhcp_option_byte(dhcp, DHCP_DECLINE);
754
755 dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
756 dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
757
758 dhcp_option_trailer(dhcp);
759 /* resize pbuf to reflect true size of options */
760 pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
761
762 /* @todo: should we really connect here? we are performing sendto() */
763 udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
764 /* per section 4.4.4, broadcast DECLINE messages */
765 udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
766 dhcp_delete_request(netif);
767 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_decline: BACKING OFF\n"));
768 } else {
769 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_decline: could not allocate DHCP request\n"));
770 }
771 dhcp->tries++;
772 msecs = 10*1000;
773 dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
774 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_decline(): set request timeout %"U16_F" msecs\n", msecs));
775 return result;
776 }
777 #endif
778
779
780 /**
781 * Start the DHCP process, discover a DHCP server.
782 *
783 * @param netif the netif under DHCP control
784 */
785 static err_t
dhcp_discover(struct netif * netif)786 dhcp_discover(struct netif *netif)
787 {
788 struct dhcp *dhcp = netif->dhcp;
789 err_t result = ERR_OK;
790 u16_t msecs;
791 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_discover()\n"));
792 ip_addr_set(&dhcp->offered_ip_addr, IP_ADDR_ANY);
793 dhcp_set_state(dhcp, DHCP_SELECTING);
794 /* create and initialize the DHCP message header */
795 result = dhcp_create_request(netif);
796 if (result == ERR_OK) {
797 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: making request\n"));
798 dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
799 dhcp_option_byte(dhcp, DHCP_DISCOVER);
800
801 dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
802 dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
803
804 dhcp_option(dhcp, DHCP_OPTION_PARAMETER_REQUEST_LIST, 4/*num options*/);
805 dhcp_option_byte(dhcp, DHCP_OPTION_SUBNET_MASK);
806 dhcp_option_byte(dhcp, DHCP_OPTION_ROUTER);
807 dhcp_option_byte(dhcp, DHCP_OPTION_BROADCAST);
808 dhcp_option_byte(dhcp, DHCP_OPTION_DNS_SERVER);
809
810 dhcp_option_trailer(dhcp);
811
812 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: realloc()ing\n"));
813 pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
814
815 udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
816 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT)\n"));
817 udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
818 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_discover: deleting()ing\n"));
819 dhcp_delete_request(netif);
820 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover: SELECTING\n"));
821 } else {
822 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_discover: could not allocate DHCP request\n"));
823 }
824 dhcp->tries++;
825 #if LWIP_DHCP_AUTOIP_COOP
826 if(dhcp->tries >= LWIP_DHCP_AUTOIP_COOP_TRIES && dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_OFF) {
827 dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_ON;
828 autoip_start(netif);
829 }
830 #endif /* LWIP_DHCP_AUTOIP_COOP */
831 msecs = (dhcp->tries < 6 ? 1 << dhcp->tries : 60) * 1000;
832 dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
833 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_discover(): set request timeout %"U16_F" msecs\n", msecs));
834 return result;
835 }
836
837
838 /**
839 * Bind the interface to the offered IP address.
840 *
841 * @param netif network interface to bind to the offered address
842 */
843 static void
dhcp_bind(struct netif * netif)844 dhcp_bind(struct netif *netif)
845 {
846 u32_t timeout;
847 struct dhcp *dhcp;
848 struct ip_addr sn_mask, gw_addr;
849 LWIP_ERROR("dhcp_bind: netif != NULL", (netif != NULL), return;);
850 dhcp = netif->dhcp;
851 LWIP_ERROR("dhcp_bind: dhcp != NULL", (dhcp != NULL), return;);
852 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_bind(netif=%p) %c%c%"U16_F"\n", (void*)netif, netif->name[0], netif->name[1], (u16_t)netif->num));
853
854 /* temporary DHCP lease? */
855 if (dhcp->offered_t1_renew != 0xffffffffUL) {
856 /* set renewal period timer */
857 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t1 renewal timer %"U32_F" secs\n", dhcp->offered_t1_renew));
858 timeout = (dhcp->offered_t1_renew + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS;
859 if(timeout > 0xffff) {
860 timeout = 0xffff;
861 }
862 dhcp->t1_timeout = (u16_t)timeout;
863 if (dhcp->t1_timeout == 0) {
864 dhcp->t1_timeout = 1;
865 }
866 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t1_renew*1000));
867 }
868 /* set renewal period timer */
869 if (dhcp->offered_t2_rebind != 0xffffffffUL) {
870 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_bind(): t2 rebind timer %"U32_F" secs\n", dhcp->offered_t2_rebind));
871 timeout = (dhcp->offered_t2_rebind + DHCP_COARSE_TIMER_SECS / 2) / DHCP_COARSE_TIMER_SECS;
872 if(timeout > 0xffff) {
873 timeout = 0xffff;
874 }
875 dhcp->t2_timeout = (u16_t)timeout;
876 if (dhcp->t2_timeout == 0) {
877 dhcp->t2_timeout = 1;
878 }
879 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_bind(): set request timeout %"U32_F" msecs\n", dhcp->offered_t2_rebind*1000));
880 }
881 /* copy offered network mask */
882 ip_addr_set(&sn_mask, &dhcp->offered_sn_mask);
883
884 /* subnet mask not given? */
885 /* TODO: this is not a valid check. what if the network mask is 0? */
886 if (sn_mask.addr == 0) {
887 /* choose a safe subnet mask given the network class */
888 u8_t first_octet = ip4_addr1(&sn_mask);
889 if (first_octet <= 127) {
890 sn_mask.addr = htonl(0xff000000);
891 } else if (first_octet >= 192) {
892 sn_mask.addr = htonl(0xffffff00);
893 } else {
894 sn_mask.addr = htonl(0xffff0000);
895 }
896 }
897
898 ip_addr_set(&gw_addr, &dhcp->offered_gw_addr);
899 /* gateway address not given? */
900 if (gw_addr.addr == 0) {
901 /* copy network address */
902 gw_addr.addr = (dhcp->offered_ip_addr.addr & sn_mask.addr);
903 /* use first host address on network as gateway */
904 gw_addr.addr |= htonl(0x00000001);
905 }
906
907 #if LWIP_DHCP_AUTOIP_COOP
908 if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
909 autoip_stop(netif);
910 dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
911 }
912 #endif /* LWIP_DHCP_AUTOIP_COOP */
913
914 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): IP: 0x%08"X32_F"\n", dhcp->offered_ip_addr.addr));
915 netif_set_ipaddr(netif, &dhcp->offered_ip_addr);
916 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): SN: 0x%08"X32_F"\n", sn_mask.addr));
917 netif_set_netmask(netif, &sn_mask);
918 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_STATE, ("dhcp_bind(): GW: 0x%08"X32_F"\n", gw_addr.addr));
919 netif_set_gw(netif, &gw_addr);
920 /* bring the interface up */
921 netif_set_up(netif);
922 /* netif is now bound to DHCP leased address */
923 dhcp_set_state(dhcp, DHCP_BOUND);
924 }
925
926 /**
927 * Renew an existing DHCP lease at the involved DHCP server.
928 *
929 * @param netif network interface which must renew its lease
930 */
931 err_t
dhcp_renew(struct netif * netif)932 dhcp_renew(struct netif *netif)
933 {
934 struct dhcp *dhcp = netif->dhcp;
935 err_t result;
936 u16_t msecs;
937 #if LWIP_NETIF_HOSTNAME
938 const char *p;
939 #endif /* LWIP_NETIF_HOSTNAME */
940 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_renew()\n"));
941 dhcp_set_state(dhcp, DHCP_RENEWING);
942
943 /* create and initialize the DHCP message header */
944 result = dhcp_create_request(netif);
945 if (result == ERR_OK) {
946
947 dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
948 dhcp_option_byte(dhcp, DHCP_REQUEST);
949
950 dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
951 dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
952
953 #if LWIP_NETIF_HOSTNAME
954 p = (const char*)netif->hostname;
955 if (p != NULL) {
956 dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, strlen(p));
957 while (*p) {
958 dhcp_option_byte(dhcp, *p++);
959 }
960 }
961 #endif /* LWIP_NETIF_HOSTNAME */
962
963 #if 0
964 dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
965 dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
966 #endif
967
968 #if 0
969 dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
970 dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
971 #endif
972 /* append DHCP message trailer */
973 dhcp_option_trailer(dhcp);
974
975 pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
976
977 udp_connect(dhcp->pcb, &dhcp->server_ip_addr, DHCP_SERVER_PORT);
978 udp_sendto_if(dhcp->pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif);
979 dhcp_delete_request(netif);
980
981 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_renew: RENEWING\n"));
982 } else {
983 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_renew: could not allocate DHCP request\n"));
984 }
985 dhcp->tries++;
986 /* back-off on retries, but to a maximum of 20 seconds */
987 msecs = dhcp->tries < 10 ? dhcp->tries * 2000 : 20 * 1000;
988 dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
989 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_renew(): set request timeout %"U16_F" msecs\n", msecs));
990 return result;
991 }
992
993 /**
994 * Rebind with a DHCP server for an existing DHCP lease.
995 *
996 * @param netif network interface which must rebind with a DHCP server
997 */
998 static err_t
dhcp_rebind(struct netif * netif)999 dhcp_rebind(struct netif *netif)
1000 {
1001 struct dhcp *dhcp = netif->dhcp;
1002 err_t result;
1003 u16_t msecs;
1004 #if LWIP_NETIF_HOSTNAME
1005 const char *p;
1006 #endif /* LWIP_NETIF_HOSTNAME */
1007 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind()\n"));
1008 dhcp_set_state(dhcp, DHCP_REBINDING);
1009
1010 /* create and initialize the DHCP message header */
1011 result = dhcp_create_request(netif);
1012 if (result == ERR_OK) {
1013
1014 dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
1015 dhcp_option_byte(dhcp, DHCP_REQUEST);
1016
1017 dhcp_option(dhcp, DHCP_OPTION_MAX_MSG_SIZE, DHCP_OPTION_MAX_MSG_SIZE_LEN);
1018 dhcp_option_short(dhcp, DHCP_MAX_MSG_LEN(netif));
1019
1020 #if LWIP_NETIF_HOSTNAME
1021 p = (const char*)netif->hostname;
1022 if (p != NULL) {
1023 dhcp_option(dhcp, DHCP_OPTION_HOSTNAME, strlen(p));
1024 while (*p) {
1025 dhcp_option_byte(dhcp, *p++);
1026 }
1027 }
1028 #endif /* LWIP_NETIF_HOSTNAME */
1029
1030 #if 0
1031 dhcp_option(dhcp, DHCP_OPTION_REQUESTED_IP, 4);
1032 dhcp_option_long(dhcp, ntohl(dhcp->offered_ip_addr.addr));
1033
1034 dhcp_option(dhcp, DHCP_OPTION_SERVER_ID, 4);
1035 dhcp_option_long(dhcp, ntohl(dhcp->server_ip_addr.addr));
1036 #endif
1037
1038 dhcp_option_trailer(dhcp);
1039
1040 pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
1041
1042 /* broadcast to server */
1043 udp_connect(dhcp->pcb, IP_ADDR_ANY, DHCP_SERVER_PORT);
1044 udp_sendto_if(dhcp->pcb, dhcp->p_out, IP_ADDR_BROADCAST, DHCP_SERVER_PORT, netif);
1045 dhcp_delete_request(netif);
1046 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind: REBINDING\n"));
1047 } else {
1048 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_rebind: could not allocate DHCP request\n"));
1049 }
1050 dhcp->tries++;
1051 msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000;
1052 dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
1053 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_rebind(): set request timeout %"U16_F" msecs\n", msecs));
1054 return result;
1055 }
1056
1057 /**
1058 * Release a DHCP lease.
1059 *
1060 * @param netif network interface which must release its lease
1061 */
1062 err_t
dhcp_release(struct netif * netif)1063 dhcp_release(struct netif *netif)
1064 {
1065 struct dhcp *dhcp = netif->dhcp;
1066 err_t result;
1067 u16_t msecs;
1068 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_release()\n"));
1069
1070 /* idle DHCP client */
1071 dhcp_set_state(dhcp, DHCP_OFF);
1072 /* clean old DHCP offer */
1073 dhcp->server_ip_addr.addr = 0;
1074 dhcp->offered_ip_addr.addr = dhcp->offered_sn_mask.addr = 0;
1075 dhcp->offered_gw_addr.addr = dhcp->offered_bc_addr.addr = 0;
1076 dhcp->offered_t0_lease = dhcp->offered_t1_renew = dhcp->offered_t2_rebind = 0;
1077 dhcp->dns_count = 0;
1078
1079 /* create and initialize the DHCP message header */
1080 result = dhcp_create_request(netif);
1081 if (result == ERR_OK) {
1082 dhcp_option(dhcp, DHCP_OPTION_MESSAGE_TYPE, DHCP_OPTION_MESSAGE_TYPE_LEN);
1083 dhcp_option_byte(dhcp, DHCP_RELEASE);
1084
1085 dhcp_option_trailer(dhcp);
1086
1087 pbuf_realloc(dhcp->p_out, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN + dhcp->options_out_len);
1088
1089 udp_connect(dhcp->pcb, &dhcp->server_ip_addr, DHCP_SERVER_PORT);
1090 udp_sendto_if(dhcp->pcb, dhcp->p_out, &dhcp->server_ip_addr, DHCP_SERVER_PORT, netif);
1091 dhcp_delete_request(netif);
1092 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_release: RELEASED, DHCP_OFF\n"));
1093 } else {
1094 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_release: could not allocate DHCP request\n"));
1095 }
1096 dhcp->tries++;
1097 msecs = dhcp->tries < 10 ? dhcp->tries * 1000 : 10 * 1000;
1098 dhcp->request_timeout = (msecs + DHCP_FINE_TIMER_MSECS - 1) / DHCP_FINE_TIMER_MSECS;
1099 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("dhcp_release(): set request timeout %"U16_F" msecs\n", msecs));
1100 /* bring the interface down */
1101 netif_set_down(netif);
1102 /* remove IP address from interface */
1103 netif_set_ipaddr(netif, IP_ADDR_ANY);
1104 netif_set_gw(netif, IP_ADDR_ANY);
1105 netif_set_netmask(netif, IP_ADDR_ANY);
1106
1107 /* TODO: netif_down(netif); */
1108 return result;
1109 }
1110
1111 /**
1112 * Remove the DHCP client from the interface.
1113 *
1114 * @param netif The network interface to stop DHCP on
1115 */
1116 void
dhcp_stop(struct netif * netif)1117 dhcp_stop(struct netif *netif)
1118 {
1119 struct dhcp *dhcp = netif->dhcp;
1120 LWIP_ERROR("dhcp_stop: netif != NULL", (netif != NULL), return;);
1121 /* Remove the flag that says this netif is handled by DHCP. */
1122 netif->flags &= ~NETIF_FLAG_DHCP;
1123
1124 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_stop()\n"));
1125 /* netif is DHCP configured? */
1126 if (dhcp != NULL) {
1127 #if LWIP_DHCP_AUTOIP_COOP
1128 if(dhcp->autoip_coop_state == DHCP_AUTOIP_COOP_STATE_ON) {
1129 autoip_stop(netif);
1130 dhcp->autoip_coop_state = DHCP_AUTOIP_COOP_STATE_OFF;
1131 }
1132 #endif /* LWIP_DHCP_AUTOIP_COOP */
1133
1134 if (dhcp->pcb != NULL) {
1135 udp_remove(dhcp->pcb);
1136 dhcp->pcb = NULL;
1137 }
1138 if (dhcp->p != NULL) {
1139 pbuf_free(dhcp->p);
1140 dhcp->p = NULL;
1141 }
1142 /* free unfolded reply */
1143 dhcp_free_reply(dhcp);
1144 mem_free((void *)dhcp);
1145 netif->dhcp = NULL;
1146 }
1147 }
1148
1149 /*
1150 * Set the DHCP state of a DHCP client.
1151 *
1152 * If the state changed, reset the number of tries.
1153 *
1154 * TODO: we might also want to reset the timeout here?
1155 */
1156 static void
dhcp_set_state(struct dhcp * dhcp,u8_t new_state)1157 dhcp_set_state(struct dhcp *dhcp, u8_t new_state)
1158 {
1159 if (new_state != dhcp->state) {
1160 dhcp->state = new_state;
1161 dhcp->tries = 0;
1162 }
1163 }
1164
1165 /*
1166 * Concatenate an option type and length field to the outgoing
1167 * DHCP message.
1168 *
1169 */
1170 static void
dhcp_option(struct dhcp * dhcp,u8_t option_type,u8_t option_len)1171 dhcp_option(struct dhcp *dhcp, u8_t option_type, u8_t option_len)
1172 {
1173 LWIP_ASSERT("dhcp_option: dhcp->options_out_len + 2 + option_len <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 2U + option_len <= DHCP_OPTIONS_LEN);
1174 dhcp->msg_out->options[dhcp->options_out_len++] = option_type;
1175 dhcp->msg_out->options[dhcp->options_out_len++] = option_len;
1176 }
1177 /*
1178 * Concatenate a single byte to the outgoing DHCP message.
1179 *
1180 */
1181 static void
dhcp_option_byte(struct dhcp * dhcp,u8_t value)1182 dhcp_option_byte(struct dhcp *dhcp, u8_t value)
1183 {
1184 LWIP_ASSERT("dhcp_option_byte: dhcp->options_out_len < DHCP_OPTIONS_LEN", dhcp->options_out_len < DHCP_OPTIONS_LEN);
1185 dhcp->msg_out->options[dhcp->options_out_len++] = value;
1186 }
1187
1188 static void
dhcp_option_short(struct dhcp * dhcp,u16_t value)1189 dhcp_option_short(struct dhcp *dhcp, u16_t value)
1190 {
1191 LWIP_ASSERT("dhcp_option_short: dhcp->options_out_len + 2 <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 2U <= DHCP_OPTIONS_LEN);
1192 dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0xff00U) >> 8);
1193 dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t) (value & 0x00ffU);
1194 }
1195
1196 static void
dhcp_option_long(struct dhcp * dhcp,u32_t value)1197 dhcp_option_long(struct dhcp *dhcp, u32_t value)
1198 {
1199 LWIP_ASSERT("dhcp_option_long: dhcp->options_out_len + 4 <= DHCP_OPTIONS_LEN", dhcp->options_out_len + 4U <= DHCP_OPTIONS_LEN);
1200 dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0xff000000UL) >> 24);
1201 dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x00ff0000UL) >> 16);
1202 dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x0000ff00UL) >> 8);
1203 dhcp->msg_out->options[dhcp->options_out_len++] = (u8_t)((value & 0x000000ffUL));
1204 }
1205
1206 /**
1207 * Extract the DHCP message and the DHCP options.
1208 *
1209 * Extract the DHCP message and the DHCP options, each into a contiguous
1210 * piece of memory. As a DHCP message is variable sized by its options,
1211 * and also allows overriding some fields for options, the easy approach
1212 * is to first unfold the options into a conitguous piece of memory, and
1213 * use that further on.
1214 *
1215 */
1216 static err_t
dhcp_unfold_reply(struct dhcp * dhcp)1217 dhcp_unfold_reply(struct dhcp *dhcp)
1218 {
1219 u16_t ret;
1220 LWIP_ERROR("dhcp != NULL", (dhcp != NULL), return ERR_ARG;);
1221 LWIP_ERROR("dhcp->p != NULL", (dhcp->p != NULL), return ERR_VAL;);
1222 /* free any left-overs from previous unfolds */
1223 dhcp_free_reply(dhcp);
1224 /* options present? */
1225 if (dhcp->p->tot_len > (sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN)) {
1226 dhcp->options_in_len = dhcp->p->tot_len - (sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN);
1227 dhcp->options_in = mem_malloc(dhcp->options_in_len);
1228 if (dhcp->options_in == NULL) {
1229 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_unfold_reply(): could not allocate dhcp->options\n"));
1230 return ERR_MEM;
1231 }
1232 }
1233 dhcp->msg_in = mem_malloc(sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN);
1234 if (dhcp->msg_in == NULL) {
1235 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_unfold_reply(): could not allocate dhcp->msg_in\n"));
1236 mem_free((void *)dhcp->options_in);
1237 dhcp->options_in = NULL;
1238 return ERR_MEM;
1239 }
1240
1241 /** copy the DHCP message without options */
1242 ret = pbuf_copy_partial(dhcp->p, dhcp->msg_in, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN, 0);
1243 LWIP_ASSERT("ret == sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN", ret == sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN);
1244 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_unfold_reply(): copied %"U16_F" bytes into dhcp->msg_in[]\n",
1245 sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN));
1246
1247 if (dhcp->options_in != NULL) {
1248 /** copy the DHCP options */
1249 ret = pbuf_copy_partial(dhcp->p, dhcp->options_in, dhcp->options_in_len, sizeof(struct dhcp_msg) - DHCP_OPTIONS_LEN);
1250 LWIP_ASSERT("ret == dhcp->options_in_len", ret == dhcp->options_in_len);
1251 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("dhcp_unfold_reply(): copied %"U16_F" bytes to dhcp->options_in[]\n",
1252 dhcp->options_in_len));
1253 }
1254 LWIP_UNUSED_ARG(ret);
1255 return ERR_OK;
1256 }
1257
1258 /**
1259 * Free the incoming DHCP message including contiguous copy of
1260 * its DHCP options.
1261 *
1262 */
dhcp_free_reply(struct dhcp * dhcp)1263 static void dhcp_free_reply(struct dhcp *dhcp)
1264 {
1265 if (dhcp->msg_in != NULL) {
1266 mem_free((void *)dhcp->msg_in);
1267 dhcp->msg_in = NULL;
1268 }
1269 if (dhcp->options_in) {
1270 mem_free((void *)dhcp->options_in);
1271 dhcp->options_in = NULL;
1272 dhcp->options_in_len = 0;
1273 }
1274 LWIP_DEBUGF(DHCP_DEBUG, ("dhcp_free_reply(): free'd\n"));
1275 }
1276
1277
1278 /**
1279 * If an incoming DHCP message is in response to us, then trigger the state machine
1280 */
dhcp_recv(void * arg,struct udp_pcb * pcb,struct pbuf * p,struct ip_addr * addr,u16_t port)1281 static void dhcp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port)
1282 {
1283 struct netif *netif = (struct netif *)arg;
1284 struct dhcp *dhcp = netif->dhcp;
1285 struct dhcp_msg *reply_msg = (struct dhcp_msg *)p->payload;
1286 u8_t *options_ptr;
1287 u8_t msg_type;
1288 u8_t i;
1289 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 3, ("dhcp_recv(pbuf = %p) from DHCP server %"U16_F".%"U16_F".%"U16_F".%"U16_F" port %"U16_F"\n", (void*)p,
1290 (u16_t)(ntohl(addr->addr) >> 24 & 0xff), (u16_t)(ntohl(addr->addr) >> 16 & 0xff),
1291 (u16_t)(ntohl(addr->addr) >> 8 & 0xff), (u16_t)(ntohl(addr->addr) & 0xff), port));
1292 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("pbuf->len = %"U16_F"\n", p->len));
1293 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("pbuf->tot_len = %"U16_F"\n", p->tot_len));
1294 /* prevent warnings about unused arguments */
1295 LWIP_UNUSED_ARG(pcb);
1296 LWIP_UNUSED_ARG(addr);
1297 LWIP_UNUSED_ARG(port);
1298 dhcp->p = p;
1299 /* TODO: check packet length before reading them */
1300 if (reply_msg->op != DHCP_BOOTREPLY) {
1301 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 1, ("not a DHCP reply message, but type %"U16_F"\n", (u16_t)reply_msg->op));
1302 goto free_pbuf_and_return;
1303 }
1304 /* iterate through hardware address and match against DHCP message */
1305 for (i = 0; i < netif->hwaddr_len; i++) {
1306 if (netif->hwaddr[i] != reply_msg->chaddr[i]) {
1307 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("netif->hwaddr[%"U16_F"]==%02"X16_F" != reply_msg->chaddr[%"U16_F"]==%02"X16_F"\n",
1308 (u16_t)i, (u16_t)netif->hwaddr[i], (u16_t)i, (u16_t)reply_msg->chaddr[i]));
1309 goto free_pbuf_and_return;
1310 }
1311 }
1312 /* match transaction ID against what we expected */
1313 if (ntohl(reply_msg->xid) != dhcp->xid) {
1314 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("transaction id mismatch reply_msg->xid(%"X32_F")!=dhcp->xid(%"X32_F")\n",ntohl(reply_msg->xid),dhcp->xid));
1315 goto free_pbuf_and_return;
1316 }
1317 /* option fields could be unfold? */
1318 if (dhcp_unfold_reply(dhcp) != ERR_OK) {
1319 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("problem unfolding DHCP message - too short on memory?\n"));
1320 goto free_pbuf_and_return;
1321 }
1322
1323 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("searching DHCP_OPTION_MESSAGE_TYPE\n"));
1324 /* obtain pointer to DHCP message type */
1325 options_ptr = dhcp_get_option_ptr(dhcp, DHCP_OPTION_MESSAGE_TYPE);
1326 if (options_ptr == NULL) {
1327 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 1, ("DHCP_OPTION_MESSAGE_TYPE option not found\n"));
1328 goto free_pbuf_and_return;
1329 }
1330
1331 /* read DHCP message type */
1332 msg_type = dhcp_get_option_byte(options_ptr + 2);
1333 /* message type is DHCP ACK? */
1334 if (msg_type == DHCP_ACK) {
1335 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 1, ("DHCP_ACK received\n"));
1336 /* in requesting state? */
1337 if (dhcp->state == DHCP_REQUESTING) {
1338 dhcp_handle_ack(netif);
1339 dhcp->request_timeout = 0;
1340 #if DHCP_DOES_ARP_CHECK
1341 /* check if the acknowledged lease address is already in use */
1342 dhcp_check(netif);
1343 #else
1344 /* bind interface to the acknowledged lease address */
1345 dhcp_bind(netif);
1346 #endif
1347 }
1348 /* already bound to the given lease address? */
1349 else if ((dhcp->state == DHCP_REBOOTING) || (dhcp->state == DHCP_REBINDING) || (dhcp->state == DHCP_RENEWING)) {
1350 dhcp->request_timeout = 0;
1351 dhcp_bind(netif);
1352 }
1353 }
1354 /* received a DHCP_NAK in appropriate state? */
1355 else if ((msg_type == DHCP_NAK) &&
1356 ((dhcp->state == DHCP_REBOOTING) || (dhcp->state == DHCP_REQUESTING) ||
1357 (dhcp->state == DHCP_REBINDING) || (dhcp->state == DHCP_RENEWING ))) {
1358 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 1, ("DHCP_NAK received\n"));
1359 dhcp->request_timeout = 0;
1360 dhcp_handle_nak(netif);
1361 }
1362 /* received a DHCP_OFFER in DHCP_SELECTING state? */
1363 else if ((msg_type == DHCP_OFFER) && (dhcp->state == DHCP_SELECTING)) {
1364 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 1, ("DHCP_OFFER received in DHCP_SELECTING state\n"));
1365 dhcp->request_timeout = 0;
1366 /* remember offered lease */
1367 dhcp_handle_offer(netif);
1368 }
1369 free_pbuf_and_return:
1370 dhcp_free_reply(dhcp);
1371 pbuf_free(p);
1372 dhcp->p = NULL;
1373 }
1374
1375 /**
1376 * Create a DHCP request, fill in common headers
1377 *
1378 * @param netif the netif under DHCP control
1379 */
1380 static err_t
dhcp_create_request(struct netif * netif)1381 dhcp_create_request(struct netif *netif)
1382 {
1383 struct dhcp *dhcp;
1384 u16_t i;
1385 #ifndef DHCP_GLOBAL_XID
1386 /** default global transaction identifier starting value (easy to match
1387 * with a packet analyser). We simply increment for each new request.
1388 * Predefine DHCP_GLOBAL_XID to a better value or a function call to generate one
1389 * at runtime, any supporting function prototypes can be defined in DHCP_GLOBAL_XID_HEADER */
1390 static u32_t xid = 0xABCD0000;
1391 #else
1392 static u32_t xid;
1393 static u8_t xid_initialised = 0;
1394 if (!xid_initialised) {
1395 xid = DHCP_GLOBAL_XID;
1396 xid_initialised = !xid_initialised;
1397 }
1398 #endif
1399 LWIP_ERROR("dhcp_create_request: netif != NULL", (netif != NULL), return ERR_ARG;);
1400 dhcp = netif->dhcp;
1401 LWIP_ERROR("dhcp_create_request: dhcp != NULL", (dhcp != NULL), return ERR_VAL;);
1402 LWIP_ASSERT("dhcp_create_request: dhcp->p_out == NULL", dhcp->p_out == NULL);
1403 LWIP_ASSERT("dhcp_create_request: dhcp->msg_out == NULL", dhcp->msg_out == NULL);
1404 dhcp->p_out = pbuf_alloc(PBUF_TRANSPORT, sizeof(struct dhcp_msg), PBUF_RAM);
1405 if (dhcp->p_out == NULL) {
1406 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("dhcp_create_request(): could not allocate pbuf\n"));
1407 return ERR_MEM;
1408 }
1409 LWIP_ASSERT("dhcp_create_request: check that first pbuf can hold struct dhcp_msg",
1410 (dhcp->p_out->len >= sizeof(struct dhcp_msg)));
1411
1412 /* reuse transaction identifier in retransmissions */
1413 if (dhcp->tries==0)
1414 xid++;
1415 dhcp->xid = xid;
1416 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2,
1417 ("transaction id xid(%"X32_F")\n", xid));
1418
1419 dhcp->msg_out = (struct dhcp_msg *)dhcp->p_out->payload;
1420
1421 dhcp->msg_out->op = DHCP_BOOTREQUEST;
1422 /* TODO: make link layer independent */
1423 dhcp->msg_out->htype = DHCP_HTYPE_ETH;
1424 /* TODO: make link layer independent */
1425 dhcp->msg_out->hlen = DHCP_HLEN_ETH;
1426 dhcp->msg_out->hops = 0;
1427 dhcp->msg_out->xid = htonl(dhcp->xid);
1428 dhcp->msg_out->secs = 0;
1429 dhcp->msg_out->flags = 0;
1430 dhcp->msg_out->ciaddr.addr = 0;
1431 if (dhcp->state==DHCP_BOUND || dhcp->state==DHCP_RENEWING || dhcp->state==DHCP_REBINDING) {
1432 dhcp->msg_out->ciaddr.addr = netif->ip_addr.addr;
1433 }
1434 dhcp->msg_out->yiaddr.addr = 0;
1435 dhcp->msg_out->siaddr.addr = 0;
1436 dhcp->msg_out->giaddr.addr = 0;
1437 for (i = 0; i < DHCP_CHADDR_LEN; i++) {
1438 /* copy netif hardware address, pad with zeroes */
1439 dhcp->msg_out->chaddr[i] = (i < netif->hwaddr_len) ? netif->hwaddr[i] : 0/* pad byte*/;
1440 }
1441 for (i = 0; i < DHCP_SNAME_LEN; i++) {
1442 dhcp->msg_out->sname[i] = 0;
1443 }
1444 for (i = 0; i < DHCP_FILE_LEN; i++) {
1445 dhcp->msg_out->file[i] = 0;
1446 }
1447 dhcp->msg_out->cookie = htonl(0x63825363UL);
1448 dhcp->options_out_len = 0;
1449 /* fill options field with an incrementing array (for debugging purposes) */
1450 for (i = 0; i < DHCP_OPTIONS_LEN; i++) {
1451 dhcp->msg_out->options[i] = (u8_t)i; /* for debugging only, no matter if truncated */
1452 }
1453 return ERR_OK;
1454 }
1455
1456 /**
1457 * Free previously allocated memory used to send a DHCP request.
1458 *
1459 * @param netif the netif under DHCP control
1460 */
1461 static void
dhcp_delete_request(struct netif * netif)1462 dhcp_delete_request(struct netif *netif)
1463 {
1464 struct dhcp *dhcp;
1465 LWIP_ERROR("dhcp_delete_request: netif != NULL", (netif != NULL), return;);
1466 dhcp = netif->dhcp;
1467 LWIP_ERROR("dhcp_delete_request: dhcp != NULL", (dhcp != NULL), return;);
1468 LWIP_ASSERT("dhcp_delete_request: dhcp->p_out != NULL", dhcp->p_out != NULL);
1469 LWIP_ASSERT("dhcp_delete_request: dhcp->msg_out != NULL", dhcp->msg_out != NULL);
1470 if (dhcp->p_out != NULL) {
1471 pbuf_free(dhcp->p_out);
1472 }
1473 dhcp->p_out = NULL;
1474 dhcp->msg_out = NULL;
1475 }
1476
1477 /**
1478 * Add a DHCP message trailer
1479 *
1480 * Adds the END option to the DHCP message, and if
1481 * necessary, up to three padding bytes.
1482 *
1483 * @param dhcp DHCP state structure
1484 */
1485 static void
dhcp_option_trailer(struct dhcp * dhcp)1486 dhcp_option_trailer(struct dhcp *dhcp)
1487 {
1488 LWIP_ERROR("dhcp_option_trailer: dhcp != NULL", (dhcp != NULL), return;);
1489 LWIP_ASSERT("dhcp_option_trailer: dhcp->msg_out != NULL\n", dhcp->msg_out != NULL);
1490 LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN);
1491 dhcp->msg_out->options[dhcp->options_out_len++] = DHCP_OPTION_END;
1492 /* packet is too small, or not 4 byte aligned? */
1493 while ((dhcp->options_out_len < DHCP_MIN_OPTIONS_LEN) || (dhcp->options_out_len & 3)) {
1494 /* LWIP_DEBUGF(DHCP_DEBUG,("dhcp_option_trailer:dhcp->options_out_len=%"U16_F", DHCP_OPTIONS_LEN=%"U16_F, dhcp->options_out_len, DHCP_OPTIONS_LEN)); */
1495 LWIP_ASSERT("dhcp_option_trailer: dhcp->options_out_len < DHCP_OPTIONS_LEN\n", dhcp->options_out_len < DHCP_OPTIONS_LEN);
1496 /* add a fill/padding byte */
1497 dhcp->msg_out->options[dhcp->options_out_len++] = 0;
1498 }
1499 }
1500
1501 /**
1502 * Find the offset of a DHCP option inside the DHCP message.
1503 *
1504 * @param dhcp DHCP client
1505 * @param option_type
1506 *
1507 * @return a byte offset into the UDP message where the option was found, or
1508 * zero if the given option was not found.
1509 */
dhcp_get_option_ptr(struct dhcp * dhcp,u8_t option_type)1510 static u8_t *dhcp_get_option_ptr(struct dhcp *dhcp, u8_t option_type)
1511 {
1512 u8_t overload = DHCP_OVERLOAD_NONE;
1513
1514 /* options available? */
1515 if ((dhcp->options_in != NULL) && (dhcp->options_in_len > 0)) {
1516 /* start with options field */
1517 u8_t *options = (u8_t *)dhcp->options_in;
1518 u16_t offset = 0;
1519 /* at least 1 byte to read and no end marker, then at least 3 bytes to read? */
1520 while ((offset < dhcp->options_in_len) && (options[offset] != DHCP_OPTION_END)) {
1521 /* LWIP_DEBUGF(DHCP_DEBUG, ("msg_offset=%"U16_F", q->len=%"U16_F, msg_offset, q->len)); */
1522 /* are the sname and/or file field overloaded with options? */
1523 if (options[offset] == DHCP_OPTION_OVERLOAD) {
1524 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 2, ("overloaded message detected\n"));
1525 /* skip option type and length */
1526 offset += 2;
1527 overload = options[offset++];
1528 }
1529 /* requested option found */
1530 else if (options[offset] == option_type) {
1531 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("option found at offset %"U16_F" in options\n", offset));
1532 return &options[offset];
1533 /* skip option */
1534 } else {
1535 LWIP_DEBUGF(DHCP_DEBUG, ("skipping option %"U16_F" in options\n", options[offset]));
1536 /* skip option type */
1537 offset++;
1538 /* skip option length, and then length bytes */
1539 offset += 1 + options[offset];
1540 }
1541 }
1542 /* is this an overloaded message? */
1543 if (overload != DHCP_OVERLOAD_NONE) {
1544 u16_t field_len;
1545 if (overload == DHCP_OVERLOAD_FILE) {
1546 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 1, ("overloaded file field\n"));
1547 options = (u8_t *)&dhcp->msg_in->file;
1548 field_len = DHCP_FILE_LEN;
1549 } else if (overload == DHCP_OVERLOAD_SNAME) {
1550 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 1, ("overloaded sname field\n"));
1551 options = (u8_t *)&dhcp->msg_in->sname;
1552 field_len = DHCP_SNAME_LEN;
1553 /* TODO: check if else if () is necessary */
1554 } else {
1555 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE | 1, ("overloaded sname and file field\n"));
1556 options = (u8_t *)&dhcp->msg_in->sname;
1557 field_len = DHCP_FILE_LEN + DHCP_SNAME_LEN;
1558 }
1559 offset = 0;
1560
1561 /* at least 1 byte to read and no end marker */
1562 while ((offset < field_len) && (options[offset] != DHCP_OPTION_END)) {
1563 if (options[offset] == option_type) {
1564 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("option found at offset=%"U16_F"\n", offset));
1565 return &options[offset];
1566 /* skip option */
1567 } else {
1568 LWIP_DEBUGF(DHCP_DEBUG | LWIP_DBG_TRACE, ("skipping option %"U16_F"\n", options[offset]));
1569 /* skip option type */
1570 offset++;
1571 offset += 1 + options[offset];
1572 }
1573 }
1574 }
1575 }
1576 return NULL;
1577 }
1578
1579 /**
1580 * Return the byte of DHCP option data.
1581 *
1582 * @param client DHCP client.
1583 * @param ptr pointer obtained by dhcp_get_option_ptr().
1584 *
1585 * @return byte value at the given address.
1586 */
1587 static u8_t
dhcp_get_option_byte(u8_t * ptr)1588 dhcp_get_option_byte(u8_t *ptr)
1589 {
1590 LWIP_DEBUGF(DHCP_DEBUG, ("option byte value=%"U16_F"\n", (u16_t)(*ptr)));
1591 return *ptr;
1592 }
1593
1594 #if 0 /* currently unused */
1595 /**
1596 * Return the 16-bit value of DHCP option data.
1597 *
1598 * @param client DHCP client.
1599 * @param ptr pointer obtained by dhcp_get_option_ptr().
1600 *
1601 * @return byte value at the given address.
1602 */
1603 static u16_t
1604 dhcp_get_option_short(u8_t *ptr)
1605 {
1606 u16_t value;
1607 value = *ptr++ << 8;
1608 value |= *ptr;
1609 LWIP_DEBUGF(DHCP_DEBUG, ("option short value=%"U16_F"\n", value));
1610 return value;
1611 }
1612 #endif
1613
1614 /**
1615 * Return the 32-bit value of DHCP option data.
1616 *
1617 * @param client DHCP client.
1618 * @param ptr pointer obtained by dhcp_get_option_ptr().
1619 *
1620 * @return byte value at the given address.
1621 */
dhcp_get_option_long(u8_t * ptr)1622 static u32_t dhcp_get_option_long(u8_t *ptr)
1623 {
1624 u32_t value;
1625 value = (u32_t)(*ptr++) << 24;
1626 value |= (u32_t)(*ptr++) << 16;
1627 value |= (u32_t)(*ptr++) << 8;
1628 value |= (u32_t)(*ptr++);
1629 LWIP_DEBUGF(DHCP_DEBUG, ("option long value=%"U32_F"\n", value));
1630 return value;
1631 }
1632
1633 #endif /* LWIP_DHCP */
1634