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");
47 listen_mode = new_mode;
52 if (new_mode == LISTEN_KERNEL)
53 sockfd = udhcp_listen_socket(/*INADDR_ANY,*/ CLIENT_PORT, client_config.interface);
54 else if (new_mode != LISTEN_NONE)
55 sockfd = udhcp_raw_socket(client_config.ifindex);
56 /* else LISTEN_NONE: sockfd stay closed */
61 static void perform_renew(void)
63 bb_info_msg("Performing a DHCP renew");
66 change_listen_mode(LISTEN_KERNEL);
69 state = RENEW_REQUESTED;
71 case RENEW_REQUESTED: /* impatient are we? fine, square 1 */
72 udhcp_run_script(NULL, "deconfig");
75 change_listen_mode(LISTEN_RAW);
76 state = INIT_SELECTING;
84 /* perform a release */
85 static void perform_release(uint32_t requested_ip, uint32_t server_addr)
87 char buffer[sizeof("255.255.255.255")];
88 struct in_addr temp_addr;
90 /* send release packet */
91 if (state == BOUND || state == RENEWING || state == REBINDING) {
92 temp_addr.s_addr = server_addr;
93 strcpy(buffer, inet_ntoa(temp_addr));
94 temp_addr.s_addr = requested_ip;
95 bb_info_msg("Unicasting a release of %s to %s",
96 inet_ntoa(temp_addr), buffer);
97 send_release(server_addr, requested_ip); /* unicast */
98 udhcp_run_script(NULL, "deconfig");
100 bb_info_msg("Entering released state");
102 change_listen_mode(LISTEN_NONE);
108 static void client_background(void)
111 logmode &= ~LOGMODE_STDIO;
112 /* rewrite pidfile, as our pid is different now */
113 write_pidfile(client_config.pidfile);
118 static uint8_t* alloc_dhcp_option(int code, const char *str, int extra)
121 int len = strlen(str);
122 if (len > 255) len = 255;
123 storage = xzalloc(len + extra + OPT_DATA);
124 storage[OPT_CODE] = code;
125 storage[OPT_LEN] = len + extra;
126 memcpy(storage + extra + OPT_DATA, str, len);
131 int udhcpc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
132 int udhcpc_main(int argc UNUSED_PARAM, char **argv)
134 uint8_t *temp, *message;
135 char *str_c, *str_V, *str_h, *str_F, *str_r;
136 IF_FEATURE_UDHCP_PORT(char *str_P;)
137 llist_t *list_O = NULL;
138 int tryagain_timeout = 20;
139 int discover_timeout = 3;
140 int discover_retries = 3;
141 uint32_t server_addr = server_addr; /* for compiler */
142 uint32_t requested_ip = 0;
144 uint32_t lease_seconds = 0; /* can be given as 32-bit quantity */
146 int timeout; /* must be signed */
147 unsigned already_waited_sec;
152 struct dhcpMessage packet;
155 #if ENABLE_GETOPT_LONG
156 static const char udhcpc_longopts[] ALIGN1 =
157 "clientid\0" Required_argument "c"
158 "clientid-none\0" No_argument "C"
159 "vendorclass\0" Required_argument "V"
160 "hostname\0" Required_argument "H"
161 "fqdn\0" Required_argument "F"
162 "interface\0" Required_argument "i"
163 "now\0" No_argument "n"
164 "pidfile\0" Required_argument "p"
165 "quit\0" No_argument "q"
166 "release\0" No_argument "R"
167 "request\0" Required_argument "r"
168 "script\0" Required_argument "s"
169 "timeout\0" Required_argument "T"
170 "version\0" No_argument "v"
171 "retries\0" Required_argument "t"
172 "tryagain\0" Required_argument "A"
173 "syslog\0" No_argument "S"
174 "request-option\0" Required_argument "O"
175 "no-default-options\0" No_argument "o"
176 "foreground\0" No_argument "f"
177 "background\0" No_argument "b"
178 IF_FEATURE_UDHCPC_ARPING("arping\0" No_argument "a")
179 IF_FEATURE_UDHCP_PORT("client-port\0" Required_argument "P")
204 /* The rest has variable bit positions, need to be clever */
206 USE_FOR_MMU( OPTBIT_b,)
207 IF_FEATURE_UDHCPC_ARPING(OPTBIT_a,)
208 IF_FEATURE_UDHCP_PORT( OPTBIT_P,)
209 USE_FOR_MMU( OPT_b = 1 << OPTBIT_b,)
210 IF_FEATURE_UDHCPC_ARPING(OPT_a = 1 << OPTBIT_a,)
211 IF_FEATURE_UDHCP_PORT( OPT_P = 1 << OPTBIT_P,)
214 /* Default options. */
215 IF_FEATURE_UDHCP_PORT(SERVER_PORT = 67;)
216 IF_FEATURE_UDHCP_PORT(CLIENT_PORT = 68;)
217 client_config.interface = "eth0";
218 client_config.script = DEFAULT_SCRIPT;
220 /* Parse command line */
221 /* Cc: mutually exclusive; O: list; -T,-t,-A take numeric param */
222 opt_complementary = "c--C:C--c:O::T+:t+:A+";
223 IF_GETOPT_LONG(applet_long_options = udhcpc_longopts;)
224 opt = getopt32(argv, "c:CV:H:h:F:i:np:qRr:s:T:t:vSA:O:of"
226 IF_FEATURE_UDHCPC_ARPING("a")
227 IF_FEATURE_UDHCP_PORT("P:")
228 , &str_c, &str_V, &str_h, &str_h, &str_F
229 , &client_config.interface, &client_config.pidfile, &str_r /* i,p */
230 , &client_config.script /* s */
231 , &discover_timeout, &discover_retries, &tryagain_timeout /* T,t,A */
233 IF_FEATURE_UDHCP_PORT(, &str_P)
236 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, str_c, 0);
238 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, str_V, 0);
239 if (opt & (OPT_h|OPT_H))
240 client_config.hostname = alloc_dhcp_option(DHCP_HOST_NAME, str_h, 0);
242 client_config.fqdn = alloc_dhcp_option(DHCP_FQDN, str_F, 3);
244 S: 1 => Client requests Server to update A RR in DNS as well as PTR
245 O: 1 => Server indicates to client that DNS has been updated regardless
246 E: 1 => Name data is DNS format, i.e. <4>host<6>domain<3>com<0> not "host.domain.com"
247 N: 1 => Client requests Server to not update DNS
249 client_config.fqdn[OPT_DATA + 0] = 0x1;
250 /* client_config.fqdn[OPT_DATA + 1] = 0; - redundant */
251 /* client_config.fqdn[OPT_DATA + 2] = 0; - redundant */
254 requested_ip = inet_addr(str_r);
256 puts("version "BB_VER);
259 #if ENABLE_FEATURE_UDHCP_PORT
261 CLIENT_PORT = xatou16(str_P);
262 SERVER_PORT = CLIENT_PORT - 1;
266 client_config.no_default_options = 1;
268 char *optstr = llist_pop(&list_O);
269 int n = index_in_strings(dhcp_option_strings, optstr);
271 bb_error_msg_and_die("unknown option '%s'", optstr);
272 n = dhcp_options[n].code;
273 client_config.opt_mask[n >> 3] |= 1 << (n & 7);
276 if (udhcp_read_interface(client_config.interface,
277 &client_config.ifindex,
279 client_config.client_mac)
285 /* on NOMMU reexec (i.e., background) early */
286 if (!(opt & OPT_f)) {
287 bb_daemonize_or_rexec(0 /* flags */, argv);
288 logmode = LOGMODE_NONE;
292 openlog(applet_name, LOG_PID, LOG_DAEMON);
293 logmode |= LOGMODE_SYSLOG;
296 /* Make sure fd 0,1,2 are open */
298 /* Equivalent of doing a fflush after every \n */
302 write_pidfile(client_config.pidfile);
304 /* Goes to stdout (unless NOMMU) and possibly syslog */
305 bb_info_msg("%s (v"BB_VER") started", applet_name);
307 /* if not set, and not suppressed, setup the default client ID */
308 if (!client_config.clientid && !(opt & OPT_C)) {
309 client_config.clientid = alloc_dhcp_option(DHCP_CLIENT_ID, "", 7);
310 client_config.clientid[OPT_DATA] = 1;
311 memcpy(client_config.clientid + OPT_DATA+1, client_config.client_mac, 6);
314 if (!client_config.vendorclass)
315 client_config.vendorclass = alloc_dhcp_option(DHCP_VENDOR, "udhcp "BB_VER, 0);
317 /* setup the signal pipe */
320 state = INIT_SELECTING;
321 udhcp_run_script(NULL, "deconfig");
322 change_listen_mode(LISTEN_RAW);
325 already_waited_sec = 0;
327 /* Main event loop. select() waits on signal pipe and possibly
329 * "continue" statements in code below jump to the top of the loop.
332 /* silence "uninitialized!" warning */
333 unsigned timestamp_before_wait = timestamp_before_wait;
335 //bb_error_msg("sockfd:%d, listen_mode:%d", sockfd, listen_mode);
337 /* Was opening raw or udp socket here
338 * if (listen_mode != LISTEN_NONE && sockfd < 0),
339 * but on fast network renew responses return faster
340 * than we open sockets. Thus this code is moved
341 * to change_listen_mode(). Thus we open listen socket
342 * BEFORE we send renew request (see "case BOUND:"). */
344 max_fd = udhcp_sp_fd_set(&rfds, sockfd);
346 tv.tv_sec = timeout - already_waited_sec;
348 retval = 0; /* If we already timed out, fall through, else... */
350 timestamp_before_wait = (unsigned)monotonic_sec();
351 DEBUG("Waiting on select...");
352 retval = select(max_fd + 1, &rfds, NULL, NULL, &tv);
354 /* EINTR? A signal was caught, don't panic */
357 /* Else: an error occured, panic! */
358 bb_perror_msg_and_die("select");
362 /* If timeout dropped to zero, time to become active:
363 * resend discover/renew/whatever
366 /* We will restart the wait in any case */
367 already_waited_sec = 0;
371 if (packet_num < discover_retries) {
375 send_discover(xid, requested_ip); /* broadcast */
377 timeout = discover_timeout;
382 udhcp_run_script(NULL, "leasefail");
383 #if BB_MMU /* -b is not supported on NOMMU */
384 if (opt & OPT_b) { /* background if no lease */
385 bb_info_msg("No lease, forking to background");
387 /* do not background again! */
388 opt = ((opt & ~OPT_b) | OPT_f);
391 if (opt & OPT_n) { /* abort if no lease */
392 bb_info_msg("No lease, failing");
396 /* wait before trying again */
397 timeout = tryagain_timeout;
400 case RENEW_REQUESTED:
402 if (packet_num < discover_retries) {
403 /* send request packet */
404 if (state == RENEW_REQUESTED) /* unicast */
405 send_renew(xid, server_addr, requested_ip);
407 send_select(xid, server_addr, requested_ip);
409 timeout = discover_timeout;
413 /* timed out, go back to init state */
414 if (state == RENEW_REQUESTED)
415 udhcp_run_script(NULL, "deconfig");
416 change_listen_mode(LISTEN_RAW);
417 /* "discover...select...discover..." loops
418 * were seen in the wild. Treat them similarly
419 * to "no response to discover" case */
420 if (state == REQUESTING) {
421 state = INIT_SELECTING;
424 state = INIT_SELECTING;
429 /* Half of the lease passed, time to enter renewing state */
430 change_listen_mode(LISTEN_KERNEL);
431 DEBUG("Entering renew state");
433 /* fall right through */
436 /* send a request packet */
437 send_renew(xid, server_addr, requested_ip); /* unicast */
441 /* Timed out, enter rebinding state */
442 DEBUG("Entering rebinding state");
444 /* fall right through */
446 /* Lease is *really* about to run out,
447 * try to find DHCP server using broadcast */
449 /* send a request packet */
450 send_renew(xid, 0 /*INADDR_ANY*/, requested_ip); /* broadcast */
454 /* Timed out, enter init state */
455 bb_info_msg("Lease lost, entering init state");
456 udhcp_run_script(NULL, "deconfig");
457 change_listen_mode(LISTEN_RAW);
458 state = INIT_SELECTING;
459 /*timeout = 0; - already is */
464 /* yah, I know, *you* say it would never happen */
466 continue; /* back to main loop */
469 /* select() didn't timeout, something did happen. */
470 /* Is it a packet? */
471 if (listen_mode != LISTEN_NONE && FD_ISSET(sockfd, &rfds)) {
473 /* A packet is ready, read it */
475 if (listen_mode == LISTEN_KERNEL)
476 len = udhcp_recv_kernel_packet(&packet, sockfd);
478 len = udhcp_recv_raw_packet(&packet, sockfd);
479 if (len == -1) { /* error is severe, reopen socket */
480 DEBUG("error on read, %s, reopening socket", strerror(errno));
481 sleep(discover_timeout); /* 3 seconds by default */
482 change_listen_mode(listen_mode); /* just close and reopen */
484 /* If this packet will turn out to be unrelated/bogus,
485 * we will go back and wait for next one.
486 * Be sure timeout is properly decreased. */
487 already_waited_sec += (unsigned)monotonic_sec() - timestamp_before_wait;
491 if (packet.xid != xid) {
492 DEBUG("Ignoring xid %x (our xid is %x)",
493 (unsigned)packet.xid, (unsigned)xid);
497 /* Ignore packets that aren't for us */
498 if (memcmp(packet.chaddr, client_config.client_mac, 6)) {
499 DEBUG("Packet does not have our chaddr - ignoring");
503 message = get_option(&packet, DHCP_MESSAGE_TYPE);
504 if (message == NULL) {
505 bb_error_msg("cannot get message type from packet - ignoring");
511 /* Must be a DHCPOFFER to one of our xid's */
512 if (*message == DHCPOFFER) {
513 /* TODO: why we don't just fetch server's IP from IP header? */
514 temp = get_option(&packet, DHCP_SERVER_ID);
516 bb_error_msg("no server ID in message");
518 /* still selecting - this server looks bad */
520 /* it IS unaligned sometimes, don't "optimize" */
521 move_from_unaligned32(server_addr, temp);
523 requested_ip = packet.yiaddr;
525 /* enter requesting state */
529 already_waited_sec = 0;
532 case RENEW_REQUESTED:
536 if (*message == DHCPACK) {
537 temp = get_option(&packet, DHCP_LEASE_TIME);
539 bb_error_msg("no lease time with ACK, using 1 hour lease");
540 lease_seconds = 60 * 60;
542 /* it IS unaligned sometimes, don't "optimize" */
543 move_from_unaligned32(lease_seconds, temp);
544 lease_seconds = ntohl(lease_seconds);
545 lease_seconds &= 0x0fffffff; /* paranoia: must not be prone to overflows */
546 if (lease_seconds < 10) /* and not too small */
549 #if ENABLE_FEATURE_UDHCPC_ARPING
551 /* RFC 2131 3.1 paragraph 5:
552 * "The client receives the DHCPACK message with configuration
553 * parameters. The client SHOULD perform a final check on the
554 * parameters (e.g., ARP for allocated network address), and notes
555 * the duration of the lease specified in the DHCPACK message. At this
556 * point, the client is configured. If the client detects that the
557 * address is already in use (e.g., through the use of ARP),
558 * the client MUST send a DHCPDECLINE message to the server and restarts
559 * the configuration process..." */
560 if (!arpping(packet.yiaddr,
563 client_config.client_mac,
564 client_config.interface)
566 bb_info_msg("offered address is in use "
567 "(got ARP reply), declining");
568 send_decline(xid, server_addr, packet.yiaddr);
570 if (state != REQUESTING)
571 udhcp_run_script(NULL, "deconfig");
572 change_listen_mode(LISTEN_RAW);
573 state = INIT_SELECTING;
575 timeout = tryagain_timeout;
577 already_waited_sec = 0;
578 continue; /* back to main loop */
582 /* enter bound state */
583 timeout = lease_seconds / 2;
585 struct in_addr temp_addr;
586 temp_addr.s_addr = packet.yiaddr;
587 bb_info_msg("Lease of %s obtained, lease time %u",
588 inet_ntoa(temp_addr), (unsigned)lease_seconds);
590 requested_ip = packet.yiaddr;
591 udhcp_run_script(&packet,
592 ((state == RENEWING || state == REBINDING) ? "renew" : "bound"));
595 change_listen_mode(LISTEN_NONE);
596 if (opt & OPT_q) { /* quit after lease */
597 if (opt & OPT_R) /* release on quit */
598 perform_release(requested_ip, server_addr);
601 #if BB_MMU /* NOMMU case backgrounded earlier */
602 if (!(opt & OPT_f)) {
604 /* do not background again! */
605 opt = ((opt & ~OPT_b) | OPT_f);
608 already_waited_sec = 0;
609 continue; /* back to main loop */
611 if (*message == DHCPNAK) {
612 /* return to init state */
613 bb_info_msg("Received DHCP NAK");
614 udhcp_run_script(&packet, "nak");
615 if (state != REQUESTING)
616 udhcp_run_script(NULL, "deconfig");
617 change_listen_mode(LISTEN_RAW);
618 sleep(3); /* avoid excessive network traffic */
619 state = INIT_SELECTING;
623 already_waited_sec = 0;
626 /* case BOUND, RELEASED: - ignore all packets */
628 continue; /* back to main loop */
631 /* select() didn't timeout, something did happen.
632 * But it wasn't a packet. It's a signal pipe then. */
634 int signo = udhcp_sp_read(&rfds);
638 /* start things over */
640 /* Kill any timeouts because the user wants this to hurry along */
644 perform_release(requested_ip, server_addr);
648 bb_info_msg("Received SIGTERM");
649 if (opt & OPT_R) /* release on quit */
650 perform_release(requested_ip, server_addr);
654 } /* for (;;) - main loop ends */
659 /*if (client_config.pidfile) - remove_pidfile has its own check */
660 remove_pidfile(client_config.pidfile);