source: MondoRescue/branches/stable/mindi-busybox/networking/udhcp/dhcpc.c@ 1096

Last change on this file since 1096 was 821, checked in by Bruno Cornec, 19 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)
File size: 14.0 KB
Line 
1/* dhcpc.c
2 *
3 * udhcp DHCP client
4 *
5 * Russ Dill <Russ.Dill@asu.edu> July 2001
6 *
7 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
8 */
9
10#include <sys/file.h>
11#include <unistd.h>
12#include <getopt.h>
13#include <stdlib.h>
14#include <sys/socket.h>
15#include <netinet/in.h>
16#include <arpa/inet.h>
17#include <signal.h>
18#include <time.h>
19#include <string.h>
20#include <sys/ioctl.h>
21#include <net/if.h>
22#include <errno.h>
23
24#include "common.h"
25#include "dhcpd.h"
26#include "dhcpc.h"
27#include "options.h"
28#include "clientpacket.h"
29#include "clientsocket.h"
30#include "socket.h"
31#include "signalpipe.h"
32
33static int state;
34static unsigned long requested_ip; /* = 0 */
35static unsigned long server_addr;
36static unsigned long timeout;
37static int packet_num; /* = 0 */
38static int fd = -1;
39
40#define LISTEN_NONE 0
41#define LISTEN_KERNEL 1
42#define LISTEN_RAW 2
43static int listen_mode;
44
45struct client_config_t client_config = {
46 /* Default options. */
47 .abort_if_no_lease = 0,
48 .foreground = 0,
49 .quit_after_lease = 0,
50 .background_if_no_lease = 0,
51 .interface = "eth0",
52 .pidfile = NULL,
53 .script = DEFAULT_SCRIPT,
54 .clientid = NULL,
55 .vendorclass = NULL,
56 .hostname = NULL,
57 .fqdn = NULL,
58 .ifindex = 0,
59 .retries = 3,
60 .timeout = 3,
61 .arp = "\0\0\0\0\0\0", /* appease gcc-3.0 */
62};
63
64/* just a little helper */
65static void change_mode(int new_mode)
66{
67 DEBUG(LOG_INFO, "entering %s listen mode",
68 new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
69 if (fd >= 0) close(fd);
70 fd = -1;
71 listen_mode = new_mode;
72}
73
74
75/* perform a renew */
76static void perform_renew(void)
77{
78 LOG(LOG_INFO, "Performing a DHCP renew");
79 switch (state) {
80 case BOUND:
81 change_mode(LISTEN_KERNEL);
82 case RENEWING:
83 case REBINDING:
84 state = RENEW_REQUESTED;
85 break;
86 case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
87 udhcp_run_script(NULL, "deconfig");
88 case REQUESTING:
89 case RELEASED:
90 change_mode(LISTEN_RAW);
91 state = INIT_SELECTING;
92 break;
93 case INIT_SELECTING:
94 break;
95 }
96
97 /* start things over */
98 packet_num = 0;
99
100 /* Kill any timeouts because the user wants this to hurry along */
101 timeout = 0;
102}
103
104
105/* perform a release */
106static void perform_release(void)
107{
108 char buffer[16];
109 struct in_addr temp_addr;
110
111 /* send release packet */
112 if (state == BOUND || state == RENEWING || state == REBINDING) {
113 temp_addr.s_addr = server_addr;
114 sprintf(buffer, "%s", inet_ntoa(temp_addr));
115 temp_addr.s_addr = requested_ip;
116 LOG(LOG_INFO, "Unicasting a release of %s to %s",
117 inet_ntoa(temp_addr), buffer);
118 send_release(server_addr, requested_ip); /* unicast */
119 udhcp_run_script(NULL, "deconfig");
120 }
121 LOG(LOG_INFO, "Entering released state");
122
123 change_mode(LISTEN_NONE);
124 state = RELEASED;
125 timeout = 0x7fffffff;
126}
127
128
129static void client_background(void)
130{
131 udhcp_background(client_config.pidfile);
132 client_config.foreground = 1; /* Do not fork again. */
133 client_config.background_if_no_lease = 0;
134}
135
136
137int udhcpc_main(int argc, char *argv[])
138{
139 uint8_t *temp, *message;
140 unsigned long t1 = 0, t2 = 0, xid = 0;
141 unsigned long start = 0, lease;
142 fd_set rfds;
143 int retval;
144 struct timeval tv;
145 int c, len;
146 struct dhcpMessage packet;
147 struct in_addr temp_addr;
148 long now;
149 int max_fd;
150 int sig;
151 int no_clientid = 0;
152
153 static const struct option arg_options[] = {
154 {"clientid", required_argument, 0, 'c'},
155 {"clientid-none", no_argument, 0, 'C'},
156 {"vendorclass", required_argument, 0, 'V'},
157 {"foreground", no_argument, 0, 'f'},
158 {"background", no_argument, 0, 'b'},
159 {"hostname", required_argument, 0, 'H'},
160 {"hostname", required_argument, 0, 'h'},
161 {"fqdn", required_argument, 0, 'F'},
162 {"interface", required_argument, 0, 'i'},
163 {"now", no_argument, 0, 'n'},
164 {"pidfile", required_argument, 0, 'p'},
165 {"quit", no_argument, 0, 'q'},
166 {"request", required_argument, 0, 'r'},
167 {"script", required_argument, 0, 's'},
168 {"timeout", required_argument, 0, 'T'},
169 {"version", no_argument, 0, 'v'},
170 {"retries", required_argument, 0, 't'},
171 {0, 0, 0, 0}
172 };
173
174 /* get options */
175 while (1) {
176 int option_index = 0;
177 c = getopt_long(argc, argv, "c:CV:fbH:h:F:i:np:qr:s:T:t:v", arg_options, &option_index);
178 if (c == -1) break;
179
180 switch (c) {
181 case 'c':
182 if (no_clientid) bb_show_usage();
183 len = strlen(optarg) > 255 ? 255 : strlen(optarg);
184 free(client_config.clientid);
185 client_config.clientid = xmalloc(len + 2);
186 client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
187 client_config.clientid[OPT_LEN] = len;
188 client_config.clientid[OPT_DATA] = '\0';
189 strncpy((char*)client_config.clientid + OPT_DATA, optarg, len);
190 break;
191 case 'C':
192 if (client_config.clientid) bb_show_usage();
193 no_clientid = 1;
194 break;
195 case 'V':
196 len = strlen(optarg) > 255 ? 255 : strlen(optarg);
197 free(client_config.vendorclass);
198 client_config.vendorclass = xmalloc(len + 2);
199 client_config.vendorclass[OPT_CODE] = DHCP_VENDOR;
200 client_config.vendorclass[OPT_LEN] = len;
201 strncpy((char*)client_config.vendorclass + OPT_DATA, optarg, len);
202 break;
203 case 'f':
204 client_config.foreground = 1;
205 break;
206 case 'b':
207 client_config.background_if_no_lease = 1;
208 break;
209 case 'h':
210 case 'H':
211 len = strlen(optarg) > 255 ? 255 : strlen(optarg);
212 free(client_config.hostname);
213 client_config.hostname = xmalloc(len + 2);
214 client_config.hostname[OPT_CODE] = DHCP_HOST_NAME;
215 client_config.hostname[OPT_LEN] = len;
216 strncpy((char*)client_config.hostname + 2, optarg, len);
217 break;
218 case 'F':
219 len = strlen(optarg) > 255 ? 255 : strlen(optarg);
220 free(client_config.fqdn);
221 client_config.fqdn = xmalloc(len + 5);
222 client_config.fqdn[OPT_CODE] = DHCP_FQDN;
223 client_config.fqdn[OPT_LEN] = len + 3;
224 /* Flags: 0000NEOS
225 S: 1 => Client requests Server to update A RR in DNS as well as PTR
226 O: 1 => Server indicates to client that DNS has been updated regardless
227 E: 1 => Name data is DNS format, i.e. <4>host<6>domain<4>com<0> not "host.domain.com"
228 N: 1 => Client requests Server to not update DNS
229 */
230 client_config.fqdn[OPT_LEN + 1] = 0x1;
231 client_config.fqdn[OPT_LEN + 2] = 0;
232 client_config.fqdn[OPT_LEN + 3] = 0;
233 strncpy((char*)client_config.fqdn + 5, optarg, len);
234 break;
235 case 'i':
236 client_config.interface = optarg;
237 break;
238 case 'n':
239 client_config.abort_if_no_lease = 1;
240 break;
241 case 'p':
242 client_config.pidfile = optarg;
243 break;
244 case 'q':
245 client_config.quit_after_lease = 1;
246 break;
247 case 'r':
248 requested_ip = inet_addr(optarg);
249 break;
250 case 's':
251 client_config.script = optarg;
252 break;
253 case 'T':
254 client_config.timeout = atoi(optarg);
255 break;
256 case 't':
257 client_config.retries = atoi(optarg);
258 break;
259 case 'v':
260 printf("version %s\n\n", BB_VER);
261 return 0;
262 break;
263 default:
264 bb_show_usage();
265 }
266 }
267
268 /* Start the log, sanitize fd's, and write a pid file */
269 udhcp_start_log_and_pid("udhcpc", client_config.pidfile);
270
271 if (read_interface(client_config.interface, &client_config.ifindex,
272 NULL, client_config.arp) < 0)
273 return 1;
274
275 /* if not set, and not suppressed, setup the default client ID */
276 if (!client_config.clientid && !no_clientid) {
277 client_config.clientid = xmalloc(6 + 3);
278 client_config.clientid[OPT_CODE] = DHCP_CLIENT_ID;
279 client_config.clientid[OPT_LEN] = 7;
280 client_config.clientid[OPT_DATA] = 1;
281 memcpy(client_config.clientid + 3, client_config.arp, 6);
282 }
283
284 if (!client_config.vendorclass) {
285 client_config.vendorclass = xmalloc(sizeof("udhcp "BB_VER) + 2);
286 client_config.vendorclass[OPT_CODE] = DHCP_VENDOR;
287 client_config.vendorclass[OPT_LEN] = sizeof("udhcp "BB_VER) - 1;
288 client_config.vendorclass[OPT_DATA] = 1;
289 memcpy(&client_config.vendorclass[OPT_DATA],
290 "udhcp "BB_VER, sizeof("udhcp "BB_VER) - 1);
291 }
292
293
294 /* setup the signal pipe */
295 udhcp_sp_setup();
296
297 state = INIT_SELECTING;
298 udhcp_run_script(NULL, "deconfig");
299 change_mode(LISTEN_RAW);
300
301 for (;;) {
302
303 tv.tv_sec = timeout - uptime();
304 tv.tv_usec = 0;
305
306 if (listen_mode != LISTEN_NONE && fd < 0) {
307 if (listen_mode == LISTEN_KERNEL)
308 fd = listen_socket(INADDR_ANY, CLIENT_PORT, client_config.interface);
309 else
310 fd = raw_socket(client_config.ifindex);
311 if (fd < 0) {
312 LOG(LOG_ERR, "FATAL: couldn't listen on socket, %m");
313 return 0;
314 }
315 }
316 max_fd = udhcp_sp_fd_set(&rfds, fd);
317
318 if (tv.tv_sec > 0) {
319 DEBUG(LOG_INFO, "Waiting on select...");
320 retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
321 } else retval = 0; /* If we already timed out, fall through */
322
323 now = uptime();
324 if (retval == 0) {
325 /* timeout dropped to zero */
326 switch (state) {
327 case INIT_SELECTING:
328 if (packet_num < client_config.retries) {
329 if (packet_num == 0)
330 xid = random_xid();
331
332 /* send discover packet */
333 send_discover(xid, requested_ip); /* broadcast */
334
335 timeout = now + client_config.timeout;
336 packet_num++;
337 } else {
338 udhcp_run_script(NULL, "leasefail");
339 if (client_config.background_if_no_lease) {
340 LOG(LOG_INFO, "No lease, forking to background.");
341 client_background();
342 } else if (client_config.abort_if_no_lease) {
343 LOG(LOG_INFO, "No lease, failing.");
344 return 1;
345 }
346 /* wait to try again */
347 packet_num = 0;
348 timeout = now + 60;
349 }
350 break;
351 case RENEW_REQUESTED:
352 case REQUESTING:
353 if (packet_num < client_config.retries) {
354 /* send request packet */
355 if (state == RENEW_REQUESTED)
356 send_renew(xid, server_addr, requested_ip); /* unicast */
357 else send_selecting(xid, server_addr, requested_ip); /* broadcast */
358
359 timeout = now + ((packet_num == 2) ? 10 : 2);
360 packet_num++;
361 } else {
362 /* timed out, go back to init state */
363 if (state == RENEW_REQUESTED) udhcp_run_script(NULL, "deconfig");
364 state = INIT_SELECTING;
365 timeout = now;
366 packet_num = 0;
367 change_mode(LISTEN_RAW);
368 }
369 break;
370 case BOUND:
371 /* Lease is starting to run out, time to enter renewing state */
372 state = RENEWING;
373 change_mode(LISTEN_KERNEL);
374 DEBUG(LOG_INFO, "Entering renew state");
375 /* fall right through */
376 case RENEWING:
377 /* Either set a new T1, or enter REBINDING state */
378 if ((t2 - t1) <= (lease / 14400 + 1)) {
379 /* timed out, enter rebinding state */
380 state = REBINDING;
381 timeout = now + (t2 - t1);
382 DEBUG(LOG_INFO, "Entering rebinding state");
383 } else {
384 /* send a request packet */
385 send_renew(xid, server_addr, requested_ip); /* unicast */
386
387 t1 = (t2 - t1) / 2 + t1;
388 timeout = t1 + start;
389 }
390 break;
391 case REBINDING:
392 /* Either set a new T2, or enter INIT state */
393 if ((lease - t2) <= (lease / 14400 + 1)) {
394 /* timed out, enter init state */
395 state = INIT_SELECTING;
396 LOG(LOG_INFO, "Lease lost, entering init state");
397 udhcp_run_script(NULL, "deconfig");
398 timeout = now;
399 packet_num = 0;
400 change_mode(LISTEN_RAW);
401 } else {
402 /* send a request packet */
403 send_renew(xid, 0, requested_ip); /* broadcast */
404
405 t2 = (lease - t2) / 2 + t2;
406 timeout = t2 + start;
407 }
408 break;
409 case RELEASED:
410 /* yah, I know, *you* say it would never happen */
411 timeout = 0x7fffffff;
412 break;
413 }
414 } else if (retval > 0 && listen_mode != LISTEN_NONE && FD_ISSET(fd, &rfds)) {
415 /* a packet is ready, read it */
416
417 if (listen_mode == LISTEN_KERNEL)
418 len = udhcp_get_packet(&packet, fd);
419 else len = get_raw_packet(&packet, fd);
420
421 if (len == -1 && errno != EINTR) {
422 DEBUG(LOG_INFO, "error on read, %m, reopening socket");
423 change_mode(listen_mode); /* just close and reopen */
424 }
425 if (len < 0) continue;
426
427 if (packet.xid != xid) {
428 DEBUG(LOG_INFO, "Ignoring XID %lx (our xid is %lx)",
429 (unsigned long) packet.xid, xid);
430 continue;
431 }
432
433 /* Ignore packets that aren't for us */
434 if (memcmp(packet.chaddr, client_config.arp, 6)) {
435 DEBUG(LOG_INFO, "packet does not have our chaddr -- ignoring");
436 continue;
437 }
438
439 if ((message = get_option(&packet, DHCP_MESSAGE_TYPE)) == NULL) {
440 DEBUG(LOG_ERR, "couldnt get option from packet -- ignoring");
441 continue;
442 }
443
444 switch (state) {
445 case INIT_SELECTING:
446 /* Must be a DHCPOFFER to one of our xid's */
447 if (*message == DHCPOFFER) {
448 if ((temp = get_option(&packet, DHCP_SERVER_ID))) {
449 memcpy(&server_addr, temp, 4);
450 xid = packet.xid;
451 requested_ip = packet.yiaddr;
452
453 /* enter requesting state */
454 state = REQUESTING;
455 timeout = now;
456 packet_num = 0;
457 } else {
458 DEBUG(LOG_ERR, "No server ID in message");
459 }
460 }
461 break;
462 case RENEW_REQUESTED:
463 case REQUESTING:
464 case RENEWING:
465 case REBINDING:
466 if (*message == DHCPACK) {
467 if (!(temp = get_option(&packet, DHCP_LEASE_TIME))) {
468 LOG(LOG_ERR, "No lease time with ACK, using 1 hour lease");
469 lease = 60 * 60;
470 } else {
471 memcpy(&lease, temp, 4);
472 lease = ntohl(lease);
473 }
474
475 /* enter bound state */
476 t1 = lease / 2;
477
478 /* little fixed point for n * .875 */
479 t2 = (lease * 0x7) >> 3;
480 temp_addr.s_addr = packet.yiaddr;
481 LOG(LOG_INFO, "Lease of %s obtained, lease time %ld",
482 inet_ntoa(temp_addr), lease);
483 start = now;
484 timeout = t1 + start;
485 requested_ip = packet.yiaddr;
486 udhcp_run_script(&packet,
487 ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
488
489 state = BOUND;
490 change_mode(LISTEN_NONE);
491 if (client_config.quit_after_lease)
492 return 0;
493 if (!client_config.foreground)
494 client_background();
495
496 } else if (*message == DHCPNAK) {
497 /* return to init state */
498 LOG(LOG_INFO, "Received DHCP NAK");
499 udhcp_run_script(&packet, "nak");
500 if (state != REQUESTING)
501 udhcp_run_script(NULL, "deconfig");
502 state = INIT_SELECTING;
503 timeout = now;
504 requested_ip = 0;
505 packet_num = 0;
506 change_mode(LISTEN_RAW);
507 sleep(3); /* avoid excessive network traffic */
508 }
509 break;
510 /* case BOUND, RELEASED: - ignore all packets */
511 }
512 } else if (retval > 0 && (sig = udhcp_sp_read(&rfds))) {
513 switch (sig) {
514 case SIGUSR1:
515 perform_renew();
516 break;
517 case SIGUSR2:
518 perform_release();
519 break;
520 case SIGTERM:
521 LOG(LOG_INFO, "Received SIGTERM");
522 return 0;
523 }
524 } else if (retval == -1 && errno == EINTR) {
525 /* a signal was caught */
526 } else {
527 /* An error occured */
528 DEBUG(LOG_ERR, "Error on select");
529 }
530
531 }
532 return 0;
533}
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