1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
|
/****************************************************************************
* netutils/dhcpc/dhcpc.c
*
* Copyright (C) 2007, 2009, 2011-2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Based heavily on portions of uIP:
*
* Author: Adam Dunkels <adam@dunkels.com>
* Copyright (c) 2005, Swedish Institute of Computer Science
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <debug.h>
#include <arpa/inet.h>
#include <apps/netutils/dhcpc.h>
#include <apps/netutils/netlib.h>
/****************************************************************************
* Definitions
****************************************************************************/
#define STATE_INITIAL 0
#define STATE_HAVE_OFFER 1
#define STATE_HAVE_LEASE 2
#define BOOTP_BROADCAST 0x8000
#define DHCP_REQUEST 1
#define DHCP_REPLY 2
#define DHCP_HTYPE_ETHERNET 1
#define DHCP_HLEN_ETHERNET 6
#define DHCP_MSG_LEN 236
#define DHCPC_SERVER_PORT 67
#define DHCPC_CLIENT_PORT 68
#define DHCPDISCOVER 1
#define DHCPOFFER 2
#define DHCPREQUEST 3
#define DHCPDECLINE 4
#define DHCPACK 5
#define DHCPNAK 6
#define DHCPRELEASE 7
#define DHCP_OPTION_SUBNET_MASK 1
#define DHCP_OPTION_ROUTER 3
#define DHCP_OPTION_DNS_SERVER 6
#define DHCP_OPTION_REQ_IPADDR 50
#define DHCP_OPTION_LEASE_TIME 51
#define DHCP_OPTION_MSG_TYPE 53
#define DHCP_OPTION_SERVER_ID 54
#define DHCP_OPTION_REQ_LIST 55
#define DHCP_OPTION_END 255
#define BUFFER_SIZE 256
/****************************************************************************
* Private Types
****************************************************************************/
struct dhcp_msg
{
uint8_t op;
uint8_t htype;
uint8_t hlen;
uint8_t hops;
uint8_t xid[4];
uint16_t secs;
uint16_t flags;
uint8_t ciaddr[4];
uint8_t yiaddr[4];
uint8_t siaddr[4];
uint8_t giaddr[4];
uint8_t chaddr[16];
#ifndef CONFIG_NET_DHCP_LIGHT
uint8_t sname[64];
uint8_t file[128];
#endif
uint8_t options[312];
};
struct dhcpc_state_s
{
const void *ds_macaddr;
int ds_maclen;
int sockfd;
struct in_addr ipaddr;
struct in_addr serverid;
struct dhcp_msg packet;
};
/****************************************************************************
* Private Data
****************************************************************************/
static const uint8_t xid[4] = {0xad, 0xde, 0x12, 0x23};
static const uint8_t magic_cookie[4] = {99, 130, 83, 99};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: dhcpc_add<option>
****************************************************************************/
static uint8_t *dhcpc_addmsgtype(uint8_t *optptr, uint8_t type)
{
*optptr++ = DHCP_OPTION_MSG_TYPE;
*optptr++ = 1;
*optptr++ = type;
return optptr;
}
static uint8_t *dhcpc_addserverid(struct in_addr *serverid, uint8_t *optptr)
{
*optptr++ = DHCP_OPTION_SERVER_ID;
*optptr++ = 4;
memcpy(optptr, &serverid->s_addr, 4);
return optptr + 4;
}
static uint8_t *dhcpc_addreqipaddr(struct in_addr *ipaddr, uint8_t *optptr)
{
*optptr++ = DHCP_OPTION_REQ_IPADDR;
*optptr++ = 4;
memcpy(optptr, &ipaddr->s_addr, 4);
return optptr + 4;
}
static uint8_t *dhcpc_addreqoptions(uint8_t *optptr)
{
*optptr++ = DHCP_OPTION_REQ_LIST;
*optptr++ = 3;
*optptr++ = DHCP_OPTION_SUBNET_MASK;
*optptr++ = DHCP_OPTION_ROUTER;
*optptr++ = DHCP_OPTION_DNS_SERVER;
return optptr;
}
static uint8_t *dhcpc_addend(uint8_t *optptr)
{
*optptr++ = DHCP_OPTION_END;
return optptr;
}
/****************************************************************************
* Name: dhcpc_sendmsg
****************************************************************************/
static int dhcpc_sendmsg(struct dhcpc_state_s *pdhcpc,
struct dhcpc_state *presult, int msgtype)
{
struct sockaddr_in addr;
uint8_t *pend;
in_addr_t serverid = INADDR_BROADCAST;
int len;
/* Create the common message header settings */
memset(&pdhcpc->packet, 0, sizeof(struct dhcp_msg));
pdhcpc->packet.op = DHCP_REQUEST;
pdhcpc->packet.htype = DHCP_HTYPE_ETHERNET;
pdhcpc->packet.hlen = pdhcpc->ds_maclen;
memcpy(pdhcpc->packet.xid, xid, 4);
memcpy(pdhcpc->packet.chaddr, pdhcpc->ds_macaddr, pdhcpc->ds_maclen);
memset(&pdhcpc->packet.chaddr[pdhcpc->ds_maclen], 0, 16 - pdhcpc->ds_maclen);
memcpy(pdhcpc->packet.options, magic_cookie, sizeof(magic_cookie));
/* Add the common header options */
pend = &pdhcpc->packet.options[4];
pend = dhcpc_addmsgtype(pend, msgtype);
/* Handle the message specific settings */
switch (msgtype)
{
/* Broadcast DISCOVER message to all servers */
case DHCPDISCOVER:
pdhcpc->packet.flags = HTONS(BOOTP_BROADCAST); /* Broadcast bit. */
pend = dhcpc_addreqoptions(pend);
break;
/* Send REQUEST message to the server that sent the *first* OFFER */
case DHCPREQUEST:
pdhcpc->packet.flags = HTONS(BOOTP_BROADCAST); /* Broadcast bit. */
memcpy(pdhcpc->packet.ciaddr, &pdhcpc->ipaddr.s_addr, 4);
pend = dhcpc_addserverid(&pdhcpc->serverid, pend);
pend = dhcpc_addreqipaddr(&pdhcpc->ipaddr, pend);
break;
/* Send DECLINE message to the server that sent the *last* OFFER */
case DHCPDECLINE:
memcpy(pdhcpc->packet.ciaddr, &presult->ipaddr.s_addr, 4);
pend = dhcpc_addserverid(&presult->serverid, pend);
serverid = presult->serverid.s_addr;
break;
default:
return ERROR;
}
pend = dhcpc_addend(pend);
len = pend - (uint8_t*)&pdhcpc->packet;
/* Send the request */
addr.sin_family = AF_INET;
addr.sin_port = HTONS(DHCPC_SERVER_PORT);
addr.sin_addr.s_addr = serverid;
return sendto(pdhcpc->sockfd, &pdhcpc->packet, len, 0,
(struct sockaddr*)&addr, sizeof(struct sockaddr_in));
}
/****************************************************************************
* Name: dhcpc_parseoptions
****************************************************************************/
static uint8_t dhcpc_parseoptions(struct dhcpc_state *presult, uint8_t *optptr, int len)
{
uint8_t *end = optptr + len;
uint8_t type = 0;
while (optptr < end)
{
switch(*optptr)
{
case DHCP_OPTION_SUBNET_MASK:
/* Get subnet mask in network order */
memcpy(&presult->netmask.s_addr, optptr + 2, 4);
break;
case DHCP_OPTION_ROUTER:
/* Get the default router address in network order */
memcpy(&presult->default_router.s_addr, optptr + 2, 4);
break;
case DHCP_OPTION_DNS_SERVER:
/* Get the DNS server address in network order */
memcpy(&presult->dnsaddr.s_addr, optptr + 2, 4);
break;
case DHCP_OPTION_MSG_TYPE:
/* Get message type */
type = *(optptr + 2);
break;
case DHCP_OPTION_SERVER_ID:
/* Get server address in network order */
memcpy(&presult->serverid.s_addr, optptr + 2, 4);
break;
case DHCP_OPTION_LEASE_TIME:
{
/* Get lease time (in seconds) in host order */
uint16_t tmp[2];
memcpy(tmp, optptr + 2, 4);
presult->lease_time = ((uint32_t)ntohs(tmp[0])) << 16 | (uint32_t)ntohs(tmp[1]);
}
break;
case DHCP_OPTION_END:
return type;
}
optptr += optptr[1] + 2;
}
return type;
}
/****************************************************************************
* Name: dhcpc_parsemsg
****************************************************************************/
static uint8_t dhcpc_parsemsg(struct dhcpc_state_s *pdhcpc, int buflen,
struct dhcpc_state *presult)
{
if (pdhcpc->packet.op == DHCP_REPLY &&
memcmp(pdhcpc->packet.xid, xid, sizeof(xid)) == 0 &&
memcmp(pdhcpc->packet.chaddr, pdhcpc->ds_macaddr, pdhcpc->ds_maclen) == 0)
{
memcpy(&presult->ipaddr.s_addr, pdhcpc->packet.yiaddr, 4);
return dhcpc_parseoptions(presult, &pdhcpc->packet.options[4], buflen);
}
return 0;
}
/****************************************************************************
* Global Functions
****************************************************************************/
/****************************************************************************
* Name: dhcpc_open
****************************************************************************/
void *dhcpc_open(const void *macaddr, int maclen)
{
struct dhcpc_state_s *pdhcpc;
struct sockaddr_in addr;
struct timeval tv;
int ret;
ndbg("MAC: %02x:%02x:%02x:%02x:%02x:%02x\n",
((uint8_t*)macaddr)[0], ((uint8_t*)macaddr)[1], ((uint8_t*)macaddr)[2],
((uint8_t*)macaddr)[3], ((uint8_t*)macaddr)[4], ((uint8_t*)macaddr)[5]);
/* Allocate an internal DHCP structure */
pdhcpc = (struct dhcpc_state_s *)malloc(sizeof(struct dhcpc_state_s));
if (pdhcpc)
{
/* Initialize the allocated structure */
memset(pdhcpc, 0, sizeof(struct dhcpc_state_s));
pdhcpc->ds_macaddr = macaddr;
pdhcpc->ds_maclen = maclen;
/* Create a UDP socket */
pdhcpc->sockfd = socket(PF_INET, SOCK_DGRAM, 0);
if (pdhcpc->sockfd < 0)
{
nvdbg("socket handle %d\n",ret);
free(pdhcpc);
return NULL;
}
/* Bind the socket */
addr.sin_family = AF_INET;
addr.sin_port = HTONS(DHCPC_CLIENT_PORT);
addr.sin_addr.s_addr = INADDR_ANY;
ret = bind(pdhcpc->sockfd, (struct sockaddr*)&addr, sizeof(struct sockaddr_in));
if (ret < 0)
{
nvdbg("bind status %d\n",ret);
close(pdhcpc->sockfd);
free(pdhcpc);
return NULL;
}
/* Configure for read timeouts */
tv.tv_sec = 10;
tv.tv_usec = 0;
ret = setsockopt(pdhcpc->sockfd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(struct timeval));
if (ret < 0)
{
nvdbg("setsockopt status %d\n",ret);
close(pdhcpc->sockfd);
free(pdhcpc);
return NULL;
}
}
return (void*)pdhcpc;
}
/****************************************************************************
* Name: dhcpc_close
****************************************************************************/
void dhcpc_close(void *handle)
{
struct dhcpc_state_s *pdhcpc = (struct dhcpc_state_s *)handle;
if (pdhcpc)
{
if (pdhcpc->sockfd)
{
close(pdhcpc->sockfd);
}
free(pdhcpc);
}
}
/****************************************************************************
* Name: dhcpc_request
****************************************************************************/
int dhcpc_request(void *handle, struct dhcpc_state *presult)
{
struct dhcpc_state_s *pdhcpc = (struct dhcpc_state_s *)handle;
struct in_addr oldaddr;
struct in_addr newaddr;
ssize_t result;
uint8_t msgtype;
int retries;
int state;
/* Save the currently assigned IP address (should be INADDR_ANY) */
oldaddr.s_addr = 0;
netlib_get_ipv4addr("eth0", &oldaddr);
/* Loop until we receive the lease (or an error occurs) */
do
{
/* Set the IP address to INADDR_ANY. */
newaddr.s_addr = INADDR_ANY;
(void)netlib_set_ipv4addr("eth0", &newaddr);
/* Loop sending DISCOVER until we receive an OFFER from a DHCP
* server. We will lock on to the first OFFER and decline any
* subsequent offers (which will happen if there are more than one
* DHCP servers on the network.
*/
state = STATE_INITIAL;
do
{
/* Send the DISCOVER command */
ndbg("Broadcast DISCOVER\n");
if (dhcpc_sendmsg(pdhcpc, presult, DHCPDISCOVER) < 0)
{
return ERROR;
}
/* Get the DHCPOFFER response */
result = recv(pdhcpc->sockfd, &pdhcpc->packet, sizeof(struct dhcp_msg), 0);
if (result >= 0)
{
msgtype = dhcpc_parsemsg(pdhcpc, result, presult);
if (msgtype == DHCPOFFER)
{
/* Save the servid from the presult so that it is not clobbered
* by a new OFFER.
*/
ndbg("Received OFFER from %08x\n", ntohl(presult->serverid.s_addr));
pdhcpc->ipaddr.s_addr = presult->ipaddr.s_addr;
pdhcpc->serverid.s_addr = presult->serverid.s_addr;
/* Temporarily use the address offered by the server and break
* out of the loop.
*/
(void)netlib_set_ipv4addr("eth0", &presult->ipaddr);
state = STATE_HAVE_OFFER;
}
}
/* An error has occurred. If this was a timeout error (meaning that
* nothing was received on this socket for a long period of time).
* Then loop and send the DISCOVER command again.
*/
else if (errno != EAGAIN)
{
/* An error other than a timeout was received -- error out */
return ERROR;
}
}
while (state == STATE_INITIAL);
/* Loop sending the REQUEST up to three times (if there is no response) */
retries = 0;
do
{
/* Send the REQUEST message to obtain the lease that was offered to us. */
ndbg("Send REQUEST\n");
if (dhcpc_sendmsg(pdhcpc, presult, DHCPREQUEST) < 0)
{
return ERROR;
}
retries++;
/* Get the ACK/NAK response to the REQUEST (or timeout) */
result = recv(pdhcpc->sockfd, &pdhcpc->packet, sizeof(struct dhcp_msg), 0);
if (result >= 0)
{
/* Parse the response */
msgtype = dhcpc_parsemsg(pdhcpc, result, presult);
/* The ACK response means that the server has accepted our request
* and we have the lease.
*/
if (msgtype == DHCPACK)
{
ndbg("Received ACK\n");
state = STATE_HAVE_LEASE;
}
/* NAK means the server has refused our request. Break out of
* this loop with state == STATE_HAVE_OFFER and send DISCOVER again
*/
else if (msgtype == DHCPNAK)
{
ndbg("Received NAK\n");
break;
}
/* If we get any OFFERs from other servers, then decline them now
* and continue waiting for the ACK from the server that we
* requested from.
*/
else if (msgtype == DHCPOFFER)
{
ndbg("Received another OFFER, send DECLINE\n");
(void)dhcpc_sendmsg(pdhcpc, presult, DHCPDECLINE);
}
/* Otherwise, it is something that we do not recognize */
else
{
ndbg("Ignoring msgtype=%d\n", msgtype);
}
}
/* An error has occurred. If this was a timeout error (meaning
* that nothing was received on this socket for a long period of time).
* Then break out and send the DISCOVER command again (at most
* 3 times).
*/
else if (errno != EAGAIN)
{
/* An error other than a timeout was received */
(void)netlib_set_ipv4addr("eth0", &oldaddr);
return ERROR;
}
}
while (state == STATE_HAVE_OFFER && retries < 3);
}
while (state != STATE_HAVE_LEASE);
ndbg("Got IP address %d.%d.%d.%d\n",
(presult->ipaddr.s_addr ) & 0xff,
(presult->ipaddr.s_addr >> 8 ) & 0xff,
(presult->ipaddr.s_addr >> 16 ) & 0xff,
(presult->ipaddr.s_addr >> 24 ) & 0xff);
ndbg("Got netmask %d.%d.%d.%d\n",
(presult->netmask.s_addr ) & 0xff,
(presult->netmask.s_addr >> 8 ) & 0xff,
(presult->netmask.s_addr >> 16 ) & 0xff,
(presult->netmask.s_addr >> 24 ) & 0xff);
ndbg("Got DNS server %d.%d.%d.%d\n",
(presult->dnsaddr.s_addr ) & 0xff,
(presult->dnsaddr.s_addr >> 8 ) & 0xff,
(presult->dnsaddr.s_addr >> 16 ) & 0xff,
(presult->dnsaddr.s_addr >> 24 ) & 0xff);
ndbg("Got default router %d.%d.%d.%d\n",
(presult->default_router.s_addr ) & 0xff,
(presult->default_router.s_addr >> 8 ) & 0xff,
(presult->default_router.s_addr >> 16 ) & 0xff,
(presult->default_router.s_addr >> 24 ) & 0xff);
ndbg("Lease expires in %d seconds\n", presult->lease_time);
return OK;
}
|