1 /* vi: set sw=4 ts=4: */
6 * Russ Dill <Russ.Dill@asu.edu> July 2001
8 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
13 /* Override ENABLE_FEATURE_PIDFILE - ifupdown needs our pidfile to always exist */
14 #define WANT_PIDFILE 1
21 static int sockfd = -1;
24 #define LISTEN_KERNEL 1
26 static smallint listen_mode;
28 #define INIT_SELECTING 0
34 #define RENEW_REQUESTED 6
36 static smallint state;
38 /* struct client_config_t client_config is in bb_common_bufsiz1 */
41 /* just a little helper */
42 static void change_listen_mode(int new_mode)
44 DEBUG("entering %s listen mode",
45 new_mode ? (new_mode == 1 ? "kernel" : "raw") : "none");
50 listen_mode = new_mode;
55 static void perform_renew(void)
57 bb_info_msg("Performing a DHCP renew");
60 change_listen_mode(LISTEN_KERNEL);
63 state = RENEW_REQUESTED;
65 case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
66 udhcp_run_script(NULL, "deconfig");
69 change_listen_mode(LISTEN_RAW);
70 state = INIT_SELECTING;
78 /* perform a release */
79 static void perform_release(uint32_t requested_ip, uint32_t server_addr)
81 char buffer[sizeof("255.255.255.255")];
82 struct in_addr temp_addr;
84 /* send release packet */
85 if (state == BOUND || state == RENEWING || state == REBINDING) {
86 temp_addr.s_addr = server_addr;
87 strcpy(buffer, inet_ntoa(temp_addr));
88 temp_addr.s_addr = requested_ip;
89 bb_info_msg("Unicasting a release of %s to %s",
90 inet_ntoa(temp_addr), buffer);
91 send_release(server_addr, requested_ip); /* unicast */
92 udhcp_run_script(NULL, "deconfig");
94 bb_info_msg("Entering released state");
96 change_listen_mode(LISTEN_NONE);
102 static void client_background(void)
105 logmode &= ~LOGMODE_STDIO;
106 /* rewrite pidfile, as our pid is different now */
107 write_pidfile(client_config.pidfile);
112 static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
115 int len = strlen(str);
116 if (len > 255) len = 255;
117 storage = xzalloc(len + extra + OPT_DATA);
118 storage[OPT_CODE] = code;
119 storage[OPT_LEN] = len + extra;
120 memcpy(storage + extra + OPT_DATA, str, len);
125 int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
126 int udhcpc_main(int argc UNUSED_PARAM, char **argv)
128 uint8_t *temp, *message;
129 char *str_c, *str_V, *str_h, *str_F, *str_r;
130 USE_FEATURE_UDHCP_PORT(char *str_P;)
131 llist_t *list_O = NULL;
132 int tryagain_timeout = 20;
133 int discover_timeout = 3;
134 int discover_retries = 3;
135 uint32_t server_addr = server_addr; /* for compiler */
136 uint32_t requested_ip = 0;
138 uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */
140 int timeout; /* must be signed */
141 unsigned already_waited_sec;
146 struct dhcpMessage packet;
149 #if ENABLE_GETOPT_LONG
150 static const char udhcpc_longopts[] ALIGN1 =
151 "clientid\0" Required_argument "c"
152 "clientid-none\0" No_argument "C"
153 "vendorclass\0" Required_argument "V"
154 "hostname\0" Required_argument "H"
155 "fqdn\0" Required_argument "F"
156 "interface\0" Required_argument "i"
157 "now\0" No_argument "n"
158 "pidfile\0" Required_argument "p"
159 "quit\0" No_argument "q"
160 "release\0" No_argument "R"
161 "request\0" Required_argument "r"
162 "script\0" Required_argument "s"
163 "timeout\0" Required_argument "T"
164 "version\0" No_argument "v"
165 "retries\0" Required_argument "t"
166 "tryagain\0" Required_argument "A"
167 "syslog\0" No_argument "S"
168 "request-option\0" Required_argument "O"
169 "no-default-options\0" No_argument "o"
170 "foreground\0" No_argument "f"
171 "background\0" No_argument "b"
172 USE_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
173 USE_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
198 /* The rest has variable bit positions, need to be clever */
200 USE_FOR_MMU( OPTBIT_b,)
201 USE_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
202 USE_FEATURE_UDHCP_PORT( OPTBIT_P,)
203 USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
204 USE_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
205 USE_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
208 /* Default options. */
209 USE_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
210 USE_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
211 client_config.interface = "eth0";
212 client_config.script = DEFAULT_SCRIPT;
214 /* Parse command line */
215 /* Cc: mutually exclusive; O: list; -T,-t,-A take numeric param */
216 opt_complementary = "c--C:C--c:O::T+:t+:A+";
217 USE_GETOPT_LONG(applet_long_options = udhcpc_longopts;)
218 opt = getopt32(argv, "c:CV:H:h:F:i:np:qRr:s:T:t:vSA:O:of"
220 USE_FEATURE_UDHCPC_ARPING("a")
221 USE_FEATURE_UDHCP_PORT("P:")
222 , &str_c, &str_V, &str_h, &str_h, &str_F
223 , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
224 , &client_config.script /* s */
225 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
227 USE_FEATURE_UDHCP_PORT(, &str_P)
230 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0);
232 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
233 if (opt & (OPT_h|OPT_H))
234 client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
236 client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
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<3>com<0> not "host.domain.com"
241 N: 1 => Client requests Server to not update DNS
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 */
248 requested_ip = inet_addr(str_r);
250 puts("version "BB_VER);
253 #if ENABLE_FEATURE_UDHCP_PORT
255 CLIENT_PORT = xatou16(str_P);
256 SERVER_PORT = CLIENT_PORT - 1;
260 client_config.no_default_options = 1;
262 char *optstr = llist_pop(&list_O);
263 int n = index_in_strings(dhcp_option_strings, optstr);
265 bb_error_msg_and_die("unknown option '%s'", optstr);
266 n = dhcp_options[n].code;
267 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
270 if (udhcp_read_interface(client_config.interface, &client_config.ifindex,
271 NULL, client_config.arp))
274 /* on NOMMU reexec (i.e., background) early */
275 if (!(opt & OPT_f)) {
276 bb_daemonize_or_rexec(0 /* flags */, argv);
281 openlog(applet_name, LOG_PID, LOG_LOCAL0);
282 logmode |= LOGMODE_SYSLOG;
285 /* Make sure fd 0,1,2 are open */
287 /* Equivalent of doing a fflush after every \n */
291 write_pidfile(client_config.pidfile);
293 /* Goes to stdout (unless NOMMU) and possibly syslog */
294 bb_info_msg("%s (v"BB_VER") started", applet_name);
296 /* if not set, and not suppressed, setup the default client ID */
297 if (!client_config.clientid && !(opt & OPT_C)) {
298 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
299 client_config.clientid[OPT_DATA] = 1;
300 memcpy(client_config.clientid + OPT_DATA+1, client_config.arp, 6);
303 if (!client_config.vendorclass)
304 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, "udhcp "BB_VER, 0);
306 /* setup the signal pipe */
309 state = INIT_SELECTING;
310 udhcp_run_script(NULL, "deconfig");
311 change_listen_mode(LISTEN_RAW);
314 already_waited_sec = 0;
316 /* Main event loop. select() waits on signal pipe and possibly
318 * "continue" statements in code below jump to the top of the loop.
321 unsigned timestamp_before_wait;
323 if (listen_mode != LISTEN_NONE && sockfd < 0) {
324 if (listen_mode == LISTEN_KERNEL)
325 sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
327 sockfd = udhcp_raw_socket(client_config.ifindex);
329 max_fd = udhcp_sp_fd_set(&rfds, sockfd);
331 tv.tv_sec = timeout - already_waited_sec;
333 retval = 0; /* If we already timed out, fall through, else... */
335 timestamp_before_wait = (unsigned)monotonic_sec();
336 DEBUG("Waiting on select...");
337 retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
339 /* EINTR? A signal was caught, don't panic */
342 /* Else: an error occured, panic! */
343 bb_perror_msg_and_die("select");
347 /* If timeout dropped to zero, time to become active:
348 * resend discover/renew/whatever
351 /* We will restart the wait in any case */
352 already_waited_sec = 0;
356 if (packet_num < discover_retries) {
360 send_discover(xid, requested_ip); /* broadcast */
362 timeout = discover_timeout;
367 udhcp_run_script(NULL, "leasefail");
368 #if BB_MMU /* -b is not supported on NOMMU */
369 if (opt & OPT_b) { /* background if no lease */
370 bb_info_msg("No lease, forking to background");
372 /* do not background again! */
373 opt = ((opt & ~OPT_b) | OPT_f);
376 if (opt & OPT_n) { /* abort if no lease */
377 bb_info_msg("No lease, failing");
381 /* wait before trying again */
382 timeout = tryagain_timeout;
385 case RENEW_REQUESTED:
387 if (packet_num < discover_retries) {
388 /* send request packet */
389 if (state == RENEW_REQUESTED) /* unicast */
390 send_renew(xid, server_addr, requested_ip);
392 send_select(xid, server_addr, requested_ip);
394 timeout = discover_timeout;
398 /* timed out, go back to init state */
399 if (state == RENEW_REQUESTED)
400 udhcp_run_script(NULL, "deconfig");
401 change_listen_mode(LISTEN_RAW);
402 state = INIT_SELECTING;
403 /* "discover...select...discover..." loops
404 * were seen in the wild. Treat then similarly
405 * to "no response to discover" case */
406 if (state == REQUESTING)
412 /* Half of the lease passed, time to enter renewing state */
413 change_listen_mode(LISTEN_KERNEL);
414 DEBUG("Entering renew state");
416 /* fall right through */
419 /* send a request packet */
420 send_renew(xid, server_addr, requested_ip); /* unicast */
424 /* Timed out, enter rebinding state */
425 DEBUG("Entering rebinding state");
427 /* fall right through */
429 /* Lease is *really* about to run out,
430 * try to find DHCP server using broadcast */
432 /* send a request packet */
433 send_renew(xid, 0 /* INADDR_ANY*/, requested_ip); /* broadcast */
437 /* Timed out, enter init state */
438 bb_info_msg("Lease lost, entering init state");
439 udhcp_run_script(NULL, "deconfig");
440 change_listen_mode(LISTEN_RAW);
441 state = INIT_SELECTING;
442 /*timeout = 0; - already is */
447 /* yah, I know, *you* say it would never happen */
449 continue; /* back to main loop */
452 /* select() didn't timeout, something did happen. */
453 /* Is is a packet? */
454 if (listen_mode != LISTEN_NONE && FD_ISSET(sockfd, &rfds)) {
456 /* A packet is ready, read it */
458 if (listen_mode == LISTEN_KERNEL)
459 len = udhcp_recv_kernel_packet(&packet, sockfd);
461 len = udhcp_recv_raw_packet(&packet, sockfd);
462 if (len == -1) { /* error is severe, reopen socket */
463 DEBUG("error on read, %s, reopening socket", strerror(errno));
464 sleep(discover_timeout); /* 3 seconds by default */
465 change_listen_mode(listen_mode); /* just close and reopen */
467 /* If this packet will turn out to be unrelated/bogus,
468 * we will go back and wait for next one.
469 * Be sure timeout is properly decreased. */
470 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
474 if (packet.xid != xid) {
475 DEBUG("Ignoring XID %x (our xid is %x)",
476 (unsigned)packet.xid, (unsigned)xid);
480 /* Ignore packets that aren't for us */
481 if (memcmp(packet.chaddr, client_config.arp, 6)) {
482 DEBUG("Packet does not have our chaddr - ignoring");
486 message = get_option(&packet, DHCP_MESSAGE_TYPE);
487 if (message == NULL) {
488 bb_error_msg("cannot get message type from packet - ignoring");
494 /* Must be a DHCPOFFER to one of our xid's */
495 if (*message == DHCPOFFER) {
496 /* TODO: why we don't just fetch server's IP from IP header? */
497 temp = get_option(&packet, DHCP_SERVER_ID);
499 bb_error_msg("no server ID in message");
501 /* still selecting - this server looks bad */
503 /* it IS unaligned sometimes, don't "optimize" */
504 server_addr = get_unaligned_u32p((uint32_t*)temp);
506 requested_ip = packet.yiaddr;
508 /* enter requesting state */
512 already_waited_sec = 0;
515 case RENEW_REQUESTED:
519 if (*message == DHCPACK) {
520 temp = get_option(&packet, DHCP_LEASE_TIME);
522 bb_error_msg("no lease time with ACK, using 1 hour lease");
523 lease_seconds = 60 * 60;
525 /* can be misaligned, thus memcpy */
526 memcpy(&lease_seconds, temp, 4);
527 lease_seconds = ntohl(lease_seconds);
528 lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */
529 if (lease_seconds < 10) /* and not too small */
532 //FIXME: why do we check ARP only after we've got DHCPACK?
533 //Shouldn't we do it immediately after DHCPOFFER?
534 #if ENABLE_FEATURE_UDHCPC_ARPING
536 if (!arpping(packet.yiaddr,
539 client_config.interface)
541 bb_info_msg("offered address is in use "
542 "(got ARP reply), declining");
543 //NB: not clear whether it should be unicast or bcast.
544 //Currently it is a bcast. Why?
545 send_decline(xid, server_addr, packet.yiaddr);
547 if (state != REQUESTING)
548 udhcp_run_script(NULL, "deconfig");
549 change_listen_mode(LISTEN_RAW);
550 state = INIT_SELECTING;
552 timeout = tryagain_timeout;
554 already_waited_sec = 0;
555 continue; /* back to main loop */
559 /* enter bound state */
560 timeout = lease_seconds / 2;
562 struct in_addr temp_addr;
563 temp_addr.s_addr = packet.yiaddr;
564 bb_info_msg("Lease of %s obtained, lease time %u",
565 inet_ntoa(temp_addr), (unsigned)lease_seconds);
567 requested_ip = packet.yiaddr;
568 udhcp_run_script(&packet,
569 ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
572 change_listen_mode(LISTEN_NONE);
573 if (opt & OPT_q) { /* quit after lease */
574 if (opt & OPT_R) /* release on quit */
575 perform_release(requested_ip, server_addr);
578 #if BB_MMU /* NOMMU case backgrounded earlier */
579 if (!(opt & OPT_f)) {
581 /* do not background again! */
582 opt = ((opt & ~OPT_b) | OPT_f);
585 already_waited_sec = 0;
586 continue; /* back to main loop */
588 if (*message == DHCPNAK) {
589 /* return to init state */
590 bb_info_msg("Received DHCP NAK");
591 udhcp_run_script(&packet, "nak");
592 if (state != REQUESTING)
593 udhcp_run_script(NULL, "deconfig");
594 change_listen_mode(LISTEN_RAW);
595 sleep(3); /* avoid excessive network traffic */
596 state = INIT_SELECTING;
600 already_waited_sec = 0;
603 /* case BOUND, RELEASED: - ignore all packets */
605 continue; /* back to main loop */
608 /* select() didn't timeout, something did happen.
609 * But it wasn't a packet. It's a signal pipe then. */
611 int signo = udhcp_sp_read(&rfds);
615 /* start things over */
617 /* Kill any timeouts because the user wants this to hurry along */
621 perform_release(requested_ip, server_addr);
625 bb_info_msg("Received SIGTERM");
626 if (opt & OPT_R) /* release on quit */
627 perform_release(requested_ip, server_addr);
631 } /* for (;;) - main loop ends */
636 /*if (client_config.pidfile) - remove_pidfile has its own check */
637 remove_pidfile(client_config.pidfile);