source: MondoRescue/branches/2.2.9/mindi-busybox/networking/udhcp/dhcpc.c@ 2142

Last change on this file since 2142 was 1765, checked in by Bruno Cornec, 16 years ago

Update to busybox 1.7.2
File size: 14.8 KB
Line 
1/* vi: set sw=4 ts=4: */
2/* dhcpc.c
3 *
4 * udhcp DHCP client
5 *
6 * Russ Dill <Russ.Dill@asu.edu> July 2001
7 *
8 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
9 */
10
11#include <getopt.h>
12#include <syslog.h>
13
14/* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
15#define WANT_PIDFILE 1
16#include "common.h"
17#include "dhcpd.h"
18#include "dhcpc.h"
19#include "options.h"
20
21
22/* Something is definitely wrong here. IPv4 addresses
23 * in variables of type long?? BTW, we use inet_ntoa()
24 * in the code. Manpage says that struct in_addr has a member of type long (!)
25 * which holds IPv4 address, and the struct is passed by value (!!)
26 */
27static unsigned timeout;
28static uint32_t requested_ip; /* = 0 */
29static uint32_t server_addr;
30static int packet_num; /* = 0 */
31static int sockfd = -1;
32
33#define LISTEN_NONE 0
34#define LISTEN_KERNEL 1
35#define LISTEN_RAW 2
36static smallint listen_mode;
37
38static smallint state;
39
40struct client_config_t client_config;
41
42
43/* just a little helper */
44static void change_mode(int new_mode)
45{
46 DEBUG("entering %s listen mode",
47 new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
48 if (sockfd >= 0) {
49 close(sockfd);
50 sockfd = -1;
51 }
52 listen_mode = new_mode;
53}
54
55
56/* perform a renew */
57static void perform_renew(void)
58{
59 bb_info_msg("Performing a DHCP renew");
60 switch (state) {
61 case BOUND:
62 change_mode(LISTEN_KERNEL);
63 case RENEWING:
64 case REBINDING:
65 state = RENEW_REQUESTED;
66 break;
67 case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
68 udhcp_run_script(NULL, "deconfig");
69 case REQUESTING:
70 case RELEASED:
71 change_mode(LISTEN_RAW);
72 state = INIT_SELECTING;
73 break;
74 case INIT_SELECTING:
75 break;
76 }
77
78 /* start things over */
79 packet_num = 0;
80
81 /* Kill any timeouts because the user wants this to hurry along */
82 timeout = 0;
83}
84
85
86/* perform a release */
87static void perform_release(void)
88{
89 char buffer[sizeof("255.255.255.255")];
90 struct in_addr temp_addr;
91
92 /* send release packet */
93 if (state == BOUND || state == RENEWING || state == REBINDING) {
94 temp_addr.s_addr = server_addr;
95 strcpy(buffer, inet_ntoa(temp_addr));
96 temp_addr.s_addr = requested_ip;
97 bb_info_msg("Unicasting a release of %s to %s",
98 inet_ntoa(temp_addr), buffer);
99 send_release(server_addr, requested_ip); /* unicast */
100 udhcp_run_script(NULL, "deconfig");
101 }
102 bb_info_msg("Entering released state");
103
104 change_mode(LISTEN_NONE);
105 state = RELEASED;
106 timeout = INT_MAX;
107}
108
109
110static void client_background(void)
111{
112#if !BB_MMU
113 bb_error_msg("cannot background in uclinux (yet)");
114/* ... mainly because udhcpc calls client_background()
115 * in _the _middle _of _udhcpc _run_, not at the start!
116 * If that will be properly disabled for NOMMU, client_background()
117 * will work on NOMMU too */
118#else
119 bb_daemonize(0);
120 logmode &= ~LOGMODE_STDIO;
121 /* rewrite pidfile, as our pid is different now */
122 write_pidfile(client_config.pidfile);
123#endif
124 /* Do not fork again. */
125 client_config.foreground = 1;
126 client_config.background_if_no_lease = 0;
127}
128
129
130static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
131{
132 uint8_t *storage;
133 int len = strlen(str);
134 if (len > 255) len = 255;
135 storage = xzalloc(len + extra + OPT_DATA);
136 storage[OPT_CODE] = code;
137 storage[OPT_LEN] = len + extra;
138 memcpy(storage + extra + OPT_DATA, str, len);
139 return storage;
140}
141
142
143int udhcpc_main(int argc, char **argv);
144int udhcpc_main(int argc, char **argv)
145{
146 uint8_t *temp, *message;
147 char *str_c, *str_V, *str_h, *str_F, *str_r, *str_T, *str_t;
148 uint32_t xid = 0;
149 uint32_t lease = 0; /* can be given as 32-bit quantity */
150 unsigned t1 = 0, t2 = 0; /* what a wonderful names */
151 unsigned start = 0;
152 unsigned now;
153 unsigned opt;
154 int max_fd;
155 int retval;
156 int len;
157 struct timeval tv;
158 struct in_addr temp_addr;
159 struct dhcpMessage packet;
160 fd_set rfds;
161
162 enum {
163 OPT_c = 1 << 0,
164 OPT_C = 1 << 1,
165 OPT_V = 1 << 2,
166 OPT_f = 1 << 3,
167 OPT_b = 1 << 4,
168 OPT_H = 1 << 5,
169 OPT_h = 1 << 6,
170 OPT_F = 1 << 7,
171 OPT_i = 1 << 8,
172 OPT_n = 1 << 9,
173 OPT_p = 1 << 10,
174 OPT_q = 1 << 11,
175 OPT_R = 1 << 12,
176 OPT_r = 1 << 13,
177 OPT_s = 1 << 14,
178 OPT_T = 1 << 15,
179 OPT_t = 1 << 16,
180 OPT_v = 1 << 17,
181 OPT_S = 1 << 18,
182 };
183#if ENABLE_GETOPT_LONG
184 static const char udhcpc_longopts[] ALIGN1 =
185 "clientid\0" Required_argument "c"
186 "clientid-none\0" No_argument "C"
187 "vendorclass\0" Required_argument "V"
188 "foreground\0" No_argument "f"
189 "background\0" No_argument "b"
190 "hostname\0" Required_argument "H"
191 "hostname\0" Required_argument "h"
192 "fqdn\0" Required_argument "F"
193 "interface\0" Required_argument "i"
194 "now\0" No_argument "n"
195 "pidfile\0" Required_argument "p"
196 "quit\0" No_argument "q"
197 "release\0" No_argument "R"
198 "request\0" Required_argument "r"
199 "script\0" Required_argument "s"
200 "timeout\0" Required_argument "T"
201 "version\0" No_argument "v"
202 "retries\0" Required_argument "t"
203 "syslog\0" No_argument "S"
204 ;
205#endif
206 /* Default options. */
207 client_config.interface = "eth0";
208 client_config.script = DEFAULT_SCRIPT;
209 client_config.retries = 3;
210 client_config.timeout = 3;
211
212 /* Parse command line */
213 opt_complementary = "c--C:C--c" // mutually exclusive
214 ":hH:Hh"; // -h and -H are the same
215#if ENABLE_GETOPT_LONG
216 applet_long_options = udhcpc_longopts;
217#endif
218 opt = getopt32(argv, "c:CV:fbH:h:F:i:np:qRr:s:T:t:vS",
219 &str_c, &str_V, &str_h, &str_h, &str_F,
220 &client_config.interface, &client_config.pidfile, &str_r,
221 &client_config.script, &str_T, &str_t
222 );
223
224 if (opt & OPT_c)
225 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0);
226 //if (opt & OPT_C)
227 if (opt & OPT_V)
228 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
229 if (opt & OPT_f)
230 client_config.foreground = 1;
231 if (opt & OPT_b)
232 client_config.background_if_no_lease = 1;
233 if (opt & OPT_h)
234 client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
235 if (opt & OPT_F) {
236 client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
237 /* Flags: 0000NEOS
238 S: 1 => Client requests Server to update A RR in DNS as well as PTR
239 O: 1 => Server indicates to client that DNS has been updated regardless
240 E: 1 => Name data is DNS format, i.e. <4>host<6>domain<4>com<0> not "host.domain.com"
241 N: 1 => Client requests Server to not update DNS
242 */
243 client_config.fqdn[OPT_DATA + 0] = 0x1;
244 /* client_config.fqdn[OPT_DATA + 1] = 0; - redundant */
245 /* client_config.fqdn[OPT_DATA + 2] = 0; - redundant */
246 }
247 // if (opt & OPT_i) client_config.interface = ...
248 if (opt & OPT_n)
249 client_config.abort_if_no_lease = 1;
250 // if (opt & OPT_p) client_config.pidfile = ...
251 if (opt & OPT_q)
252 client_config.quit_after_lease = 1;
253 if (opt & OPT_R)
254 client_config.release_on_quit = 1;
255 if (opt & OPT_r)
256 requested_ip = inet_addr(str_r);
257 // if (opt & OPT_s) client_config.script = ...
258 if (opt & OPT_T)
259 client_config.timeout = xatoi_u(str_T);
260 if (opt & OPT_t)
261 client_config.retries = xatoi_u(str_t);
262 if (opt & OPT_v) {
263 printf("version %s\n", BB_VER);
264 return 0;
265 }
266
267 if (opt & OPT_S) {
268 openlog(applet_name, LOG_PID, LOG_LOCAL0);
269 logmode |= LOGMODE_SYSLOG;
270 }
271
272 if (read_interface(client_config.interface, &client_config.ifindex,
273 NULL, client_config.arp))
274 return 1;
275
276 /* Make sure fd 0,1,2 are open */
277 bb_sanitize_stdio();
278 /* Equivalent of doing a fflush after every \n */
279 setlinebuf(stdout);
280
281 /* Create pidfile */
282 write_pidfile(client_config.pidfile);
283 /* if (!..) bb_perror_msg("cannot create pidfile %s", pidfile); */
284
285 /* Goes to stdout and possibly syslog */
286 bb_info_msg("%s (v%s) started", applet_name, BB_VER);
287
288 /* if not set, and not suppressed, setup the default client ID */
289 if (!client_config.clientid && !(opt & OPT_C)) {
290 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
291 client_config.clientid[OPT_DATA] = 1;
292 memcpy(client_config.clientid + OPT_DATA+1, client_config.arp, 6);
293 }
294
295 if (!client_config.vendorclass)
296 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, "udhcp "BB_VER, 0);
297
298 /* setup the signal pipe */
299 udhcp_sp_setup();
300
301 state = INIT_SELECTING;
302 udhcp_run_script(NULL, "deconfig");
303 change_mode(LISTEN_RAW);
304 tv.tv_sec = 0;
305 goto jump_in;
306
307 for (;;) {
308 tv.tv_sec = timeout - monotonic_sec();
309 jump_in:
310 tv.tv_usec = 0;
311
312 if (listen_mode != LISTEN_NONE && sockfd < 0) {
313 if (listen_mode == LISTEN_KERNEL)
314 sockfd = listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
315 else
316 sockfd = raw_socket(client_config.ifindex);
317 }
318 max_fd = udhcp_sp_fd_set(&rfds, sockfd);
319
320 retval = 0; /* If we already timed out, fall through, else... */
321 if (tv.tv_sec > 0) {
322 DEBUG("Waiting on select...");
323 retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
324 }
325
326 now = monotonic_sec();
327 if (retval < 0) {
328 /* EINTR? signal was caught, don't panic */
329 if (errno != EINTR) {
330 /* Else: an error occured, panic! */
331 bb_perror_msg_and_die("select");
332 }
333 } else if (retval == 0) {
334 /* timeout dropped to zero */
335 switch (state) {
336 case INIT_SELECTING:
337 if (packet_num < client_config.retries) {
338 if (packet_num == 0)
339 xid = random_xid();
340
341 /* send discover packet */
342 send_discover(xid, requested_ip); /* broadcast */
343
344 timeout = now + client_config.timeout;
345 packet_num++;
346 } else {
347 udhcp_run_script(NULL, "leasefail");
348 if (client_config.background_if_no_lease) {
349 bb_info_msg("No lease, forking to background");
350 client_background();
351 } else if (client_config.abort_if_no_lease) {
352 bb_info_msg("No lease, failing");
353 retval = 1;
354 goto ret;
355 }
356 /* wait to try again */
357 packet_num = 0;
358 timeout = now + 60;
359 }
360 break;
361 case RENEW_REQUESTED:
362 case REQUESTING:
363 if (packet_num < client_config.retries) {
364 /* send request packet */
365 if (state == RENEW_REQUESTED)
366 send_renew(xid, server_addr, requested_ip); /* unicast */
367 else send_selecting(xid, server_addr, requested_ip); /* broadcast */
368
369 timeout = now + ((packet_num == 2) ? 10 : 2);
370 packet_num++;
371 } else {
372 /* timed out, go back to init state */
373 if (state == RENEW_REQUESTED)
374 udhcp_run_script(NULL, "deconfig");
375 state = INIT_SELECTING;
376 timeout = now;
377 packet_num = 0;
378 change_mode(LISTEN_RAW);
379 }
380 break;
381 case BOUND:
382 /* Lease is starting to run out, time to enter renewing state */
383 state = RENEWING;
384 change_mode(LISTEN_KERNEL);
385 DEBUG("Entering renew state");
386 /* fall right through */
387 case RENEWING:
388 /* Either set a new T1, or enter REBINDING state */
389 if ((t2 - t1) <= (lease / 14400 + 1)) {
390 /* timed out, enter rebinding state */
391 state = REBINDING;
392 timeout = now + (t2 - t1);
393 DEBUG("Entering rebinding state");
394 } else {
395 /* send a request packet */
396 send_renew(xid, server_addr, requested_ip); /* unicast */
397 t1 = (t2 - t1) / 2 + t1;
398 timeout = start + t1;
399 }
400 break;
401 case REBINDING:
402 /* Either set a new T2, or enter INIT state */
403 if ((lease - t2) <= (lease / 14400 + 1)) {
404 /* timed out, enter init state */
405 state = INIT_SELECTING;
406 bb_info_msg("Lease lost, entering init state");
407 udhcp_run_script(NULL, "deconfig");
408 timeout = now;
409 packet_num = 0;
410 change_mode(LISTEN_RAW);
411 } else {
412 /* send a request packet */
413 send_renew(xid, 0, requested_ip); /* broadcast */
414 t2 = (lease - t2) / 2 + t2;
415 timeout = start + t2;
416 }
417 break;
418 case RELEASED:
419 /* yah, I know, *you* say it would never happen */
420 timeout = INT_MAX;
421 break;
422 }
423 } else if (listen_mode != LISTEN_NONE && FD_ISSET(sockfd, &rfds)) {
424 /* a packet is ready, read it */
425
426 if (listen_mode == LISTEN_KERNEL)
427 len = udhcp_get_packet(&packet, sockfd);
428 else len = get_raw_packet(&packet, sockfd);
429
430 if (len == -1 && errno != EINTR) {
431 DEBUG("error on read, %s, reopening socket", strerror(errno));
432 change_mode(listen_mode); /* just close and reopen */
433 }
434 if (len < 0) continue;
435
436 if (packet.xid != xid) {
437 DEBUG("Ignoring XID %x (our xid is %x)",
438 (unsigned)packet.xid, (unsigned)xid);
439 continue;
440 }
441
442 /* Ignore packets that aren't for us */
443 if (memcmp(packet.chaddr, client_config.arp, 6)) {
444 DEBUG("Packet does not have our chaddr - ignoring");
445 continue;
446 }
447
448 message = get_option(&packet, DHCP_MESSAGE_TYPE);
449 if (message == NULL) {
450 bb_error_msg("cannot get option from packet - ignoring");
451 continue;
452 }
453
454 switch (state) {
455 case INIT_SELECTING:
456 /* Must be a DHCPOFFER to one of our xid's */
457 if (*message == DHCPOFFER) {
458 temp = get_option(&packet, DHCP_SERVER_ID);
459 if (temp) {
460 /* can be misaligned, thus memcpy */
461 memcpy(&server_addr, temp, 4);
462 xid = packet.xid;
463 requested_ip = packet.yiaddr;
464
465 /* enter requesting state */
466 state = REQUESTING;
467 timeout = now;
468 packet_num = 0;
469 } else {
470 bb_error_msg("no server ID in message");
471 }
472 }
473 break;
474 case RENEW_REQUESTED:
475 case REQUESTING:
476 case RENEWING:
477 case REBINDING:
478 if (*message == DHCPACK) {
479 temp = get_option(&packet, DHCP_LEASE_TIME);
480 if (!temp) {
481 bb_error_msg("no lease time with ACK, using 1 hour lease");
482 lease = 60 * 60;
483 } else {
484 /* can be misaligned, thus memcpy */
485 memcpy(&lease, temp, 4);
486 lease = ntohl(lease);
487 }
488
489 /* enter bound state */
490 t1 = lease / 2;
491
492 /* little fixed point for n * .875 */
493 t2 = (lease * 7) >> 3;
494 temp_addr.s_addr = packet.yiaddr;
495 bb_info_msg("Lease of %s obtained, lease time %u",
496 inet_ntoa(temp_addr), (unsigned)lease);
497 start = now;
498 timeout = start + t1;
499 requested_ip = packet.yiaddr;
500 udhcp_run_script(&packet,
501 ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
502
503 state = BOUND;
504 change_mode(LISTEN_NONE);
505 if (client_config.quit_after_lease) {
506 if (client_config.release_on_quit)
507 perform_release();
508 goto ret0;
509 }
510 if (!client_config.foreground)
511 client_background();
512
513 } else if (*message == DHCPNAK) {
514 /* return to init state */
515 bb_info_msg("Received DHCP NAK");
516 udhcp_run_script(&packet, "nak");
517 if (state != REQUESTING)
518 udhcp_run_script(NULL, "deconfig");
519 state = INIT_SELECTING;
520 timeout = now;
521 requested_ip = 0;
522 packet_num = 0;
523 change_mode(LISTEN_RAW);
524 sleep(3); /* avoid excessive network traffic */
525 }
526 break;
527 /* case BOUND, RELEASED: - ignore all packets */
528 }
529 } else {
530 int signo = udhcp_sp_read(&rfds);
531 switch (signo) {
532 case SIGUSR1:
533 perform_renew();
534 break;
535 case SIGUSR2:
536 perform_release();
537 break;
538 case SIGTERM:
539 bb_info_msg("Received SIGTERM");
540 if (client_config.release_on_quit)
541 perform_release();
542 goto ret0;
543 }
544 }
545 } /* for (;;) */
546 ret0:
547 retval = 0;
548 ret:
549 /*if (client_config.pidfile) - remove_pidfile has it's own check */
550 remove_pidfile(client_config.pidfile);
551 return retval;
552}
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