1 /*
2 * Copyright 2004 Henning Brauer <henning@openbsd.org>
3 * Copyright (c) 1995, 1996, 1997, 1998, 1999
4 * The Internet Software Consortium. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of The Internet Software Consortium nor the names
16 * of its contributors may be used to endorse or promote products derived
17 * from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
20 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
21 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
22 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
23 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
24 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
27 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
28 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * This software has been written for the Internet Software Consortium
34 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
35 * Enterprises. To learn more about the Internet Software Consortium,
36 * see ``http://www.vix.com/isc''. To learn more about Vixie
37 * Enterprises, see ``http://www.vix.com''.
38 *
39 * This client was substantially modified and enhanced by Elliot Poger
40 * for use on Linux while he was working on the MosquitoNet project at
41 * Stanford.
42 *
43 * The current version owes much to Elliot's Linux enhancements, but
44 * was substantially reorganized and partially rewritten by Ted Lemon
45 * so as to use the same networking framework that the Internet Software
46 * Consortium DHCP server uses. Much system-specific configuration code
47 * was moved into a shell script so that as support for more operating
48 * systems is added, it will not be necessary to port and maintain
49 * system-specific configuration code to these operating systems - instead,
50 * the shell script can invoke the native tools to accomplish the same
51 * purpose.
52 */
53 #include <sys/ioctl.h>
54
55 #include <ctype.h>
56 #include <poll.h>
57 #include <pwd.h>
58 #include <signal.h>
59 #include <unistd.h>
60
61 #include "dhcpd.h"
62 #include "privsep.h"
63
64 #define CLIENT_PATH "PATH=/usr/bin:/usr/sbin:/bin:/sbin"
65 #define DEFAULT_LEASE_TIME 43200 /* 12 hours... */
66 #define TIME_MAX 2147483647
67 #define POLL_FAILURES 10
68 #define POLL_FAILURE_WAIT 1 /* Back off multiplier (seconds) */
69
70 char *path_dhclient_conf = _PATH_DHCLIENT_CONF;
71 char *path_dhclient_db = NULL;
72 char *orig_ifname;
73
74 int log_perror = 1;
75 int privfd;
76 int nullfd = -1;
77 int no_daemon;
78 int stayalive = 0;
79 int unknown_ok = 1;
80 int routefd = -1;
81 pid_t monitor_pid;
82
83 struct iaddr iaddr_broadcast = { 4, { 255, 255, 255, 255 } };
84 struct in_addr inaddr_any;
85 struct sockaddr_in sockaddr_broadcast;
86
87 struct interface_info *ifi;
88 struct client_state *client;
89 struct client_config *config;
90
91 int findproto(char *, int);
92 struct sockaddr *get_ifa(char *, int);
93 void usage(void) __dead2;
94 int check_option(struct client_lease *l, int option);
95 int check_classless_option(unsigned char *data, int len);
96 int ipv4addrs(char * buf);
97 int res_hnok(const char *dn);
98 char *option_as_string(unsigned int code, unsigned char *data, int len);
99 int fork_privchld(int, int);
100 void get_ifname(char *, char *);
101 static void sig_handle(int sig);
102 static int killclient(int fd);
103
104 time_t scripttime;
105 static FILE *leaseFile;
106
107 int
findproto(char * cp,int n)108 findproto(char *cp, int n)
109 {
110 struct sockaddr *sa;
111 unsigned int i;
112
113 if (n == 0)
114 return -1;
115 for (i = 1; i; i <<= 1) {
116 if (i & n) {
117 sa = (struct sockaddr *)cp;
118 switch (i) {
119 case RTA_IFA:
120 case RTA_DST:
121 case RTA_GATEWAY:
122 case RTA_NETMASK:
123 if (sa->sa_family == AF_INET)
124 return AF_INET;
125 if (sa->sa_family == AF_INET6)
126 return AF_INET6;
127 break;
128 case RTA_IFP:
129 break;
130 }
131 RT_ADVANCE(cp, sa);
132 }
133 }
134 return (-1);
135 }
136
137 struct sockaddr *
get_ifa(char * cp,int n)138 get_ifa(char *cp, int n)
139 {
140 struct sockaddr *sa;
141 int i;
142
143 if (n == 0)
144 return (NULL);
145 for (i = 1; i; i <<= 1)
146 if (i & n) {
147 sa = (struct sockaddr *)cp;
148 if (i == RTA_IFA)
149 return (sa);
150 RT_ADVANCE(cp, sa);
151 }
152
153 return (NULL);
154 }
155 struct iaddr defaddr = { .len = 4 }; /* NULL is for silence warnings */
156
157 void
routehandler(void)158 routehandler(void)
159 {
160 int linkstat;
161 char msg[2048];
162 struct rt_msghdr *rtm;
163 struct if_msghdr *ifm;
164 struct ifa_msghdr *ifam;
165 struct if_announcemsghdr *ifan;
166 struct client_lease *l;
167 struct sockaddr *sa;
168 struct iaddr a;
169 ssize_t n;
170 char *errmsg, buf[64];
171
172 do {
173 n = read(routefd, &msg, sizeof(msg));
174 } while (n == -1 && errno == EINTR);
175
176 rtm = (struct rt_msghdr *)msg;
177 if (n < sizeof(rtm->rtm_msglen) || n < rtm->rtm_msglen ||
178 rtm->rtm_version != RTM_VERSION)
179 return;
180
181 switch (rtm->rtm_type) {
182 case RTM_NEWADDR:
183 ifam = (struct ifa_msghdr *)rtm;
184 if (ifam->ifam_index != ifi->index)
185 break;
186 if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET)
187 break;
188 sa = get_ifa((char *)(ifam + 1), ifam->ifam_addrs);
189 if (sa == NULL) {
190 errmsg = "sa == NULL";
191 goto die;
192 }
193
194 if ((a.len = sizeof(struct in_addr)) > sizeof(a.iabuf))
195 error("king bula sez: len mismatch");
196 memcpy(a.iabuf, &((struct sockaddr_in *)sa)->sin_addr, a.len);
197 if (addr_eq(a, defaddr))
198 break;
199
200 /* state_panic() can try unexpired existing leases */
201 if (client->active && addr_eq(a, client->active->address))
202 break;
203 for (l = client->leases; l != NULL; l = l->next)
204 if (addr_eq(a, l->address))
205 break;
206
207 if (l != NULL)
208 /* new addr is the one we set */
209 break;
210 snprintf(buf, sizeof(buf), "%s: %s",
211 "new address not one we set", piaddr(a));
212 errmsg = buf;
213 goto die;
214 case RTM_DELADDR:
215 ifam = (struct ifa_msghdr *)rtm;
216 if (ifam->ifam_index != ifi->index)
217 break;
218 if (findproto((char *)(ifam + 1), ifam->ifam_addrs) != AF_INET)
219 break;
220 /* XXX check addrs like RTM_NEWADDR instead of this? */
221 if (scripttime == 0 || time(NULL) < scripttime + 10)
222 break;
223 errmsg = "interface address deleted";
224 goto die;
225 case RTM_IFINFO:
226 ifm = (struct if_msghdr *)rtm;
227 if (ifm->ifm_index != ifi->index)
228 break;
229 if ((rtm->rtm_flags & RTF_UP) == 0) {
230 errmsg = "interface down";
231 goto die;
232 }
233
234 linkstat =
235 LINK_STATE_IS_UP(ifm->ifm_data.ifi_link_state) ? 1 : 0;
236 if (linkstat != ifi->linkstat) {
237 #ifdef DEBUG
238 debug("link state %s -> %s",
239 ifi->linkstat ? "up" : "down",
240 linkstat ? "up" : "down");
241 #endif
242 ifi->linkstat = interface_status(ifi->name);
243 if (ifi->linkstat) {
244 client->state = S_REBOOTING;
245 state_reboot();
246 }
247 }
248 break;
249 case RTM_IFANNOUNCE:
250 ifan = (struct if_announcemsghdr *)rtm;
251 if (ifan->ifan_what == IFAN_DEPARTURE &&
252 ifan->ifan_index == ifi->index) {
253 errmsg = "interface departure";
254 goto die;
255 }
256 break;
257 default:
258 break;
259 }
260 return;
261
262 die:
263 script_init("FAIL");
264 script_go();
265 error("routehandler: %s", errmsg);
266 }
267
268 int
main(int argc,char * argv[])269 main(int argc, char *argv[])
270 {
271 int ch, fd;
272 int pipe_fd[2];
273 int quiet = 0;
274 int dokillclient = 0;
275 int i;
276 struct passwd *pw;
277
278 /* Initially, log errors to stderr as well as to syslogd. */
279 openlog(getprogname(), LOG_PID | LOG_NDELAY, DHCPD_LOG_FACILITY);
280 setlogmask(LOG_UPTO(LOG_INFO));
281
282 signal(SIGINT, sig_handle);
283 signal(SIGHUP, sig_handle);
284
285 while ((ch = getopt(argc, argv, "c:dl:quwx")) != -1) {
286 switch (ch) {
287 case 'c':
288 path_dhclient_conf = optarg;
289 break;
290 case 'd':
291 no_daemon = 1;
292 break;
293 case 'l':
294 path_dhclient_db = optarg;
295 break;
296 case 'q':
297 quiet = 1;
298 break;
299 case 'u':
300 unknown_ok = 0;
301 break;
302 case 'w':
303 stayalive = 1;
304 break;
305 case 'x':
306 dokillclient = 1;
307 break;
308 default:
309 usage();
310 }
311 }
312
313 argc -= optind;
314 argv += optind;
315
316 /*
317 * dport wpa_supplicant uses 'start ifc' instead of 'ifc', allow
318 * the 'start' keyword.
319 */
320 if (argc > 1) {
321 if (strcmp(argv[0], "start") == 0) {
322 --argc;
323 ++argv;
324 stayalive = 1;
325 } else if (strcmp(argv[0], "stop") == 0) {
326 dokillclient = 1;
327 --argc;
328 ++argv;
329 }
330 }
331
332 if (argc != 1)
333 usage();
334 orig_ifname = argv[0];
335
336 if (dokillclient) {
337 char buf[256];
338
339 snprintf(buf, sizeof(buf),
340 "/var/run/dhclient.%s.pid", orig_ifname);
341 fd = open(buf, O_RDWR, 0644);
342 if (fd < 0 || killclient(fd)) {
343 fprintf(stderr,
344 "no dhclient running on %s\n",
345 orig_ifname);
346 } else {
347 fprintf(stderr,
348 "stopping dhclient on %s\n",
349 orig_ifname);
350 }
351 if (fd >= 0)
352 close(fd);
353 exit(1);
354 }
355
356 if ((nullfd = open(_PATH_DEVNULL, O_RDWR, 0)) == -1)
357 error("cannot open %s: %m", _PATH_DEVNULL);
358
359 /*
360 * If asked to stay alive forever get our daemon going right now
361 * Then set up to fork/monitor and refork on exit.
362 *
363 * When I say 'forever' I really mean it. If there are configuration
364 * problems or missing interfaces or whatever, dhclient will wait
365 * 10 seconds and try again.
366 */
367 if (stayalive) {
368 pid_t pid;
369 pid_t rpid;
370 int omask;
371
372 go_daemon();
373
374 for (;;) {
375 omask = sigblock(sigmask(SIGINT) | sigmask(SIGHUP));
376 pid = fork();
377 if (pid > 0)
378 monitor_pid = pid;
379 sigsetmask(omask);
380
381 if (pid == 0) /* child falls out of loop */
382 break;
383 while (pid > 0) {
384 rpid = waitpid(pid, NULL, 0);
385 if (rpid == pid)
386 break;
387 if (rpid != EINTR)
388 break;
389 }
390 sleep(10);
391 }
392 }
393
394 ifi = calloc(1, sizeof(*ifi));
395 if (ifi == NULL)
396 error("ifi calloc");
397 client = calloc(1, sizeof(*client));
398 if (client == NULL)
399 error("client calloc");
400 config = calloc(1, sizeof(*config));
401 if (config == NULL)
402 error("config calloc");
403
404 get_ifname(ifi->name, argv[0]);
405
406 if (path_dhclient_db == NULL && asprintf(&path_dhclient_db, "%s.%s",
407 _PATH_DHCLIENT_DB, ifi->name) == -1)
408 error("asprintf");
409
410 if (quiet)
411 log_perror = 0;
412
413 tzset();
414
415 memset(&sockaddr_broadcast, 0, sizeof(sockaddr_broadcast));
416 sockaddr_broadcast.sin_family = AF_INET;
417 sockaddr_broadcast.sin_port = htons(REMOTE_PORT);
418 sockaddr_broadcast.sin_addr.s_addr = INADDR_BROADCAST;
419 sockaddr_broadcast.sin_len = sizeof(sockaddr_broadcast);
420 inaddr_any.s_addr = INADDR_ANY;
421
422 read_client_conf();
423
424 if (interface_status(ifi->name) == 0) {
425 interface_link_forceup(ifi->name);
426 /* Give it up to 4 seconds of silent grace to find link */
427 i = -4;
428 } else {
429 i = 0;
430 }
431
432 while (!(ifi->linkstat = interface_status(ifi->name))) {
433 if (i == 0)
434 fprintf(stderr, "%s: no link ...", ifi->name);
435 else if (i > 0)
436 fprintf(stderr, ".");
437 fflush(stderr);
438 if (++i > config->link_timeout) {
439 fprintf(stderr, " sleeping\n");
440 goto dispatch;
441 }
442 sleep(1);
443 }
444 if (i > 0)
445 fprintf(stderr, " got link\n");
446
447 dispatch:
448 if ((pw = getpwnam("_dhcp")) == NULL)
449 error("no such user: _dhcp");
450
451 if (pipe(pipe_fd) == -1)
452 error("pipe");
453
454 go_daemon();
455 fork_privchld(pipe_fd[0], pipe_fd[1]);
456
457 close(pipe_fd[0]);
458 privfd = pipe_fd[1];
459
460 if ((fd = open(path_dhclient_db, O_RDONLY|O_EXLOCK|O_CREAT, 0)) == -1)
461 error("can't open and lock %s: %m", path_dhclient_db);
462 read_client_leases();
463 if ((leaseFile = fopen(path_dhclient_db, "w")) == NULL)
464 error("can't open %s: %m", path_dhclient_db);
465 rewrite_client_leases();
466 close(fd);
467
468 if ((routefd = socket(PF_ROUTE, SOCK_RAW, 0)) == -1)
469 error("socket(PF_ROUTE, SOCK_RAW): %m");
470
471 /* set up the interface */
472 discover_interface();
473
474 if (chroot(_PATH_VAREMPTY) == -1)
475 error("chroot");
476 if (chdir("/") == -1)
477 error("chdir(\"/\")");
478
479 if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1)
480 error("setresgid");
481 if (setgroups(1, &pw->pw_gid) == -1)
482 error("setgroups");
483 if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
484 error("setresuid");
485
486 endpwent();
487
488 setproctitle("%s", ifi->name);
489
490 if (ifi->linkstat) {
491 client->state = S_REBOOTING;
492 state_reboot();
493 }
494 dispatch();
495
496 /* not reached */
497 return (0);
498 }
499
500 void
usage(void)501 usage(void)
502 {
503 fprintf(stderr, "usage: %s [-dqu] [-c file] [-l file] interface\n",
504 getprogname());
505 exit(1);
506 }
507
508 /*
509 * Individual States:
510 *
511 * Each routine is called from the dhclient_state_machine() in one of
512 * these conditions:
513 * -> entering INIT state
514 * -> recvpacket_flag == 0: timeout in this state
515 * -> otherwise: received a packet in this state
516 *
517 * Return conditions as handled by dhclient_state_machine():
518 * Returns 1, sendpacket_flag = 1: send packet, reset timer.
519 * Returns 1, sendpacket_flag = 0: just reset the timer (wait for a milestone).
520 * Returns 0: finish the nap which was interrupted for no good reason.
521 *
522 * Several per-interface variables are used to keep track of the process:
523 * active_lease: the lease that is being used on the interface
524 * (null pointer if not configured yet).
525 * offered_leases: leases corresponding to DHCPOFFER messages that have
526 * been sent to us by DHCP servers.
527 * acked_leases: leases corresponding to DHCPACK messages that have been
528 * sent to us by DHCP servers.
529 * sendpacket: DHCP packet we're trying to send.
530 * destination: IP address to send sendpacket to
531 * In addition, there are several relevant per-lease variables.
532 * T1_expiry, T2_expiry, lease_expiry: lease milestones
533 * In the active lease, these control the process of renewing the lease;
534 * In leases on the acked_leases list, this simply determines when we
535 * can no longer legitimately use the lease.
536 */
537 void
state_reboot(void)538 state_reboot(void)
539 {
540 /* Cancel all timeouts, since a link state change gets us here
541 and can happen anytime. */
542 cancel_timeout();
543
544 /* If we don't remember an active lease, go straight to INIT. */
545 if (!client->active || client->active->is_bootp) {
546 client->state = S_INIT;
547 state_init();
548 return;
549 }
550
551 /* make_request doesn't initialize xid because it normally comes
552 from the DHCPDISCOVER, but we haven't sent a DHCPDISCOVER,
553 so pick an xid now. */
554 client->xid = arc4random();
555
556 /* Make a DHCPREQUEST packet, and set appropriate per-interface
557 flags. */
558 make_request(client->active);
559 client->destination = iaddr_broadcast;
560 client->first_sending = time(NULL);
561 client->interval = 0;
562
563 send_request();
564 }
565
566 /*
567 * Called when a lease has completely expired and we've
568 * been unable to renew it.
569 */
570 void
state_init(void)571 state_init(void)
572 {
573 /* Make a DHCPDISCOVER packet, and set appropriate per-interface
574 flags. */
575 make_discover(client->active);
576 client->xid = client->packet.xid;
577 client->destination = iaddr_broadcast;
578 client->state = S_SELECTING;
579 client->first_sending = time(NULL);
580 client->interval = 0;
581
582 send_discover();
583 }
584
585 /*
586 * state_selecting is called when one or more DHCPOFFER packets
587 * have been received and a configurable period of time has passed.
588 */
589 void
state_selecting(void)590 state_selecting(void)
591 {
592 struct client_lease *lp, *next, *picked;
593 time_t cur_time;
594
595 /* Cancel state_selecting and send_discover timeouts, since either
596 one could have got us here. */
597 cancel_timeout();
598
599 /* We have received one or more DHCPOFFER packets. Currently,
600 the only criterion by which we judge leases is whether or
601 not we get a response when we arp for them. */
602 picked = NULL;
603 for (lp = client->offered_leases; lp; lp = next) {
604 next = lp->next;
605
606 if (!picked) {
607 picked = lp;
608 } else {
609 make_decline(lp);
610 send_decline();
611 free_client_lease(lp);
612 }
613 }
614 client->offered_leases = NULL;
615
616 /* If we just tossed all the leases we were offered, go back
617 to square one. */
618 if (!picked) {
619 client->state = S_INIT;
620 state_init();
621 return;
622 }
623 picked->next = NULL;
624
625 time(&cur_time);
626
627 /* If it was a BOOTREPLY, we can just take the address right now. */
628 if (!picked->options[DHO_DHCP_MESSAGE_TYPE].len) {
629 client->new = picked;
630
631 /* Make up some lease expiry times
632 XXX these should be configurable. */
633 client->new->expiry = cur_time + 12000;
634 client->new->renewal += cur_time + 8000;
635 client->new->rebind += cur_time + 10000;
636
637 client->state = S_REQUESTING;
638
639 /* Bind to the address we received. */
640 bind_lease();
641 return;
642 }
643
644 /* Go to the REQUESTING state. */
645 client->destination = iaddr_broadcast;
646 client->state = S_REQUESTING;
647 client->first_sending = cur_time;
648 client->interval = 0;
649
650 /* Make a DHCPREQUEST packet from the lease we picked. */
651 make_request(picked);
652 client->xid = client->packet.xid;
653
654 /* Toss the lease we picked - we'll get it back in a DHCPACK. */
655 free_client_lease(picked);
656
657 send_request();
658 }
659
660 void
dhcpack(struct iaddr client_addr,struct option_data * options)661 dhcpack(struct iaddr client_addr, struct option_data *options)
662 {
663 struct client_lease *lease;
664 time_t cur_time;
665
666
667 if (client->state != S_REBOOTING &&
668 client->state != S_REQUESTING &&
669 client->state != S_RENEWING &&
670 client->state != S_REBINDING)
671 return;
672
673
674 lease = packet_to_lease(options);
675 if (!lease) {
676 note("packet_to_lease failed.");
677 return;
678 }
679
680 client->new = lease;
681
682 /* Stop resending DHCPREQUEST. */
683 cancel_timeout();
684
685 /* Figure out the lease time. */
686 if (client->new->options[DHO_DHCP_LEASE_TIME].data)
687 client->new->expiry =
688 getULong(client->new->options[DHO_DHCP_LEASE_TIME].data);
689 else
690 client->new->expiry = DEFAULT_LEASE_TIME;
691 /* A number that looks negative here is really just very large,
692 because the lease expiry offset is unsigned. */
693 if (client->new->expiry < 0)
694 client->new->expiry = TIME_MAX;
695 /* XXX should be fixed by resetting the client state */
696 if (client->new->expiry < 60)
697 client->new->expiry = 60;
698
699 /* Take the server-provided renewal time if there is one;
700 otherwise figure it out according to the spec. */
701 if (client->new->options[DHO_DHCP_RENEWAL_TIME].len)
702 client->new->renewal =
703 getULong(client->new->options[DHO_DHCP_RENEWAL_TIME].data);
704 else
705 client->new->renewal = client->new->expiry / 2;
706
707 /* Same deal with the rebind time. */
708 if (client->new->options[DHO_DHCP_REBINDING_TIME].len)
709 client->new->rebind =
710 getULong(client->new->options[DHO_DHCP_REBINDING_TIME].data);
711 else
712 client->new->rebind = client->new->renewal +
713 client->new->renewal / 2 + client->new->renewal / 4;
714
715 time(&cur_time);
716
717 client->new->expiry += cur_time;
718 /* Lease lengths can never be negative. */
719 if (client->new->expiry < cur_time)
720 client->new->expiry = TIME_MAX;
721 client->new->renewal += cur_time;
722 if (client->new->renewal < cur_time)
723 client->new->renewal = TIME_MAX;
724 client->new->rebind += cur_time;
725 if (client->new->rebind < cur_time)
726 client->new->rebind = TIME_MAX;
727
728 bind_lease();
729 }
730
731 void
bind_lease(void)732 bind_lease(void)
733 {
734 /* Run the client script with the new parameters. */
735 script_init((client->state == S_REQUESTING ? "BOUND" :
736 (client->state == S_RENEWING ? "RENEW" :
737 (client->state == S_REBOOTING ? "REBOOT" : "REBIND"))));
738 if (client->active && client->state != S_REBOOTING)
739 script_write_params("old_", client->active);
740 script_write_params("new_", client->new);
741 script_go();
742
743 /* Replace the old active lease with the new one. */
744 if (client->active)
745 free_client_lease(client->active);
746 client->active = client->new;
747 client->new = NULL;
748
749 /* Write out new leases file. */
750 rewrite_client_leases();
751
752 /* Set timeout to start the renewal process. */
753 set_timeout(client->active->renewal, state_bound);
754
755 note("bound to %s -- renewal in %lld seconds.",
756 piaddr(client->active->address),
757 (long long)(client->active->renewal - time(NULL)));
758 client->state = S_BOUND;
759 }
760
761 /*
762 * state_bound is called when we've successfully bound to a particular
763 * lease, but the renewal time on that lease has expired. We are
764 * expected to unicast a DHCPREQUEST to the server that gave us our
765 * original lease.
766 */
767 void
state_bound(void)768 state_bound(void)
769 {
770 /* T1 has expired. */
771 make_request(client->active);
772 client->xid = client->packet.xid;
773
774 if (client->active->options[DHO_DHCP_SERVER_IDENTIFIER].len == 4) {
775 memcpy(client->destination.iabuf,
776 client->active->options[DHO_DHCP_SERVER_IDENTIFIER].data,
777 4);
778 client->destination.len = 4;
779 } else
780 client->destination = iaddr_broadcast;
781
782 client->first_sending = time(NULL);
783 client->interval = 0;
784 client->state = S_RENEWING;
785
786 send_request();
787 }
788
789 void
dhcpoffer(struct iaddr client_addr,struct option_data * options)790 dhcpoffer(struct iaddr client_addr, struct option_data *options)
791 {
792 struct client_lease *lease, *lp;
793 int i;
794 time_t stop_selecting;
795 char *name = options[DHO_DHCP_MESSAGE_TYPE].len ? "DHCPOFFER" :
796 "BOOTREPLY";
797
798
799 if (client->state != S_SELECTING)
800 return;
801
802
803 /* If this lease doesn't supply the minimum required parameters,
804 blow it off. */
805 for (i = 0; config->required_options[i]; i++) {
806 if (!options[config->required_options[i]].len) {
807 note("%s isn't satisfactory.", name);
808 return;
809 }
810 }
811
812 /* If we've already seen this lease, don't record it again. */
813 for (lease = client->offered_leases;
814 lease; lease = lease->next) {
815 if (lease->address.len == sizeof(client->packet.yiaddr) &&
816 !memcmp(lease->address.iabuf,
817 &client->packet.yiaddr, lease->address.len)) {
818 #ifdef DEBUG
819 debug("%s already seen.", name);
820 #endif
821 return;
822 }
823 }
824
825 lease = packet_to_lease(options);
826 if (!lease) {
827 note("packet_to_lease failed.");
828 return;
829 }
830
831 /*
832 * Reject offers whose subnet is already configured on another
833 * interface.
834 */
835 if (subnet_exists(lease))
836 return;
837
838 /* If this lease was acquired through a BOOTREPLY, record that
839 fact. */
840 if (!options[DHO_DHCP_MESSAGE_TYPE].len)
841 lease->is_bootp = 1;
842
843 /* Figure out when we're supposed to stop selecting. */
844 stop_selecting = client->first_sending + config->select_interval;
845
846 /* If this is the lease we asked for, put it at the head of the
847 list, and don't mess with the arp request timeout. */
848 if (addr_eq(lease->address, client->requested_address)) {
849 lease->next = client->offered_leases;
850 client->offered_leases = lease;
851 } else {
852 /* Put the lease at the end of the list. */
853 lease->next = NULL;
854 if (!client->offered_leases)
855 client->offered_leases = lease;
856 else {
857 for (lp = client->offered_leases; lp->next;
858 lp = lp->next)
859 ; /* nothing */
860 lp->next = lease;
861 }
862 }
863
864 /* If the selecting interval has expired, go immediately to
865 state_selecting(). Otherwise, time out into
866 state_selecting at the select interval. */
867 if (stop_selecting <= time(NULL))
868 state_selecting();
869 else {
870 set_timeout(stop_selecting, state_selecting);
871 }
872 }
873
874 /*
875 * Allocate a client_lease structure and initialize it from the
876 * parameters in the specified packet.
877 */
878 struct client_lease *
packet_to_lease(struct option_data * options)879 packet_to_lease(struct option_data *options)
880 {
881 struct client_lease *lease;
882 int i;
883
884 lease = malloc(sizeof(struct client_lease));
885
886 if (!lease) {
887 warning("dhcpoffer: no memory to record lease.");
888 return (NULL);
889 }
890
891 memset(lease, 0, sizeof(*lease));
892
893 /* Copy the lease options. */
894 for (i = 0; i < 256; i++) {
895 if (options[i].len) {
896 lease->options[i] = options[i];
897 options[i].data = NULL;
898 options[i].len = 0;
899 if (!check_option(lease, i)) {
900 warning("Invalid lease option - ignoring offer");
901 free_client_lease(lease);
902 return (NULL);
903 }
904 }
905 }
906
907 lease->address.len = sizeof(client->packet.yiaddr);
908 memcpy(lease->address.iabuf, &client->packet.yiaddr,
909 lease->address.len);
910
911 /* If the server name was filled out, copy it. */
912 if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len ||
913 !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)) &&
914 client->packet.sname[0]) {
915 lease->server_name = malloc(DHCP_SNAME_LEN + 1);
916 if (!lease->server_name) {
917 warning("dhcpoffer: no memory for server name.");
918 free_client_lease(lease);
919 return (NULL);
920 }
921 memcpy(lease->server_name, client->packet.sname,
922 DHCP_SNAME_LEN);
923 lease->server_name[DHCP_SNAME_LEN] = '\0';
924 if (!res_hnok(lease->server_name)) {
925 warning("Bogus server name %s", lease->server_name);
926 free(lease->server_name);
927 lease->server_name = NULL;
928 }
929 }
930
931 /* Ditto for the filename. */
932 if ((!lease->options[DHO_DHCP_OPTION_OVERLOAD].len ||
933 !(lease->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)) &&
934 client->packet.file[0]) {
935 /* Don't count on the NUL terminator. */
936 lease->filename = malloc(DHCP_FILE_LEN + 1);
937 if (!lease->filename) {
938 warning("dhcpoffer: no memory for filename.");
939 free_client_lease(lease);
940 return (NULL);
941 }
942 memcpy(lease->filename, client->packet.file, DHCP_FILE_LEN);
943 lease->filename[DHCP_FILE_LEN] = '\0';
944 }
945 return lease;
946 }
947
948 void
dhcpnak(struct iaddr client_addr,struct option_data * options)949 dhcpnak(struct iaddr client_addr, struct option_data *options)
950 {
951
952 if (client->state != S_REBOOTING &&
953 client->state != S_REQUESTING &&
954 client->state != S_RENEWING &&
955 client->state != S_REBINDING)
956 return;
957
958
959 if (!client->active) {
960 note("DHCPNAK with no active lease.");
961 return;
962 }
963
964 free_client_lease(client->active);
965 client->active = NULL;
966
967 /* Stop sending DHCPREQUEST packets... */
968 cancel_timeout();
969
970 client->state = S_INIT;
971 state_init();
972 }
973
974 /*
975 * Send out a DHCPDISCOVER packet, and set a timeout to send out another
976 * one after the right interval has expired. If we don't get an offer by
977 * the time we reach the panic interval, call the panic function.
978 */
979 void
send_discover(void)980 send_discover(void)
981 {
982 time_t cur_time;
983 int interval, increase = 1;
984
985 time(&cur_time);
986
987 /* Figure out how long it's been since we started transmitting. */
988 interval = cur_time - client->first_sending;
989
990 /* If we're past the panic timeout, call the script and tell it
991 we haven't found anything for this interface yet. */
992 if (interval > config->timeout) {
993 state_panic();
994 return;
995 }
996
997 /*
998 * If we're supposed to increase the interval, do so. If it's
999 * currently zero (i.e., we haven't sent any packets yet), set
1000 * it to initial_interval; otherwise, add to it a random
1001 * number between zero and two times itself. On average, this
1002 * means that it will double with every transmission.
1003 */
1004 if (increase) {
1005 if (!client->interval)
1006 client->interval = config->initial_interval;
1007 else {
1008 client->interval += (arc4random() >> 2) %
1009 (2 * client->interval);
1010 }
1011
1012 /* Don't backoff past cutoff. */
1013 if (client->interval > config->backoff_cutoff)
1014 client->interval = ((config->backoff_cutoff / 2)
1015 + ((arc4random() >> 2) %
1016 config->backoff_cutoff));
1017 } else if (!client->interval)
1018 client->interval = config->initial_interval;
1019
1020 /* If the backoff would take us to the panic timeout, just use that
1021 as the interval. */
1022 if (cur_time + client->interval >
1023 client->first_sending + config->timeout)
1024 client->interval = (client->first_sending +
1025 config->timeout) - cur_time + 1;
1026
1027 /* Record the number of seconds since we started sending. */
1028 if (interval < 65536)
1029 client->packet.secs = htons(interval);
1030 else
1031 client->packet.secs = htons(65535);
1032 client->secs = client->packet.secs;
1033
1034 note("DHCPDISCOVER on %s to %s port %d interval %ld",
1035 ifi->name, inet_ntoa(sockaddr_broadcast.sin_addr),
1036 ntohs(sockaddr_broadcast.sin_port), client->interval);
1037
1038 send_packet(inaddr_any, &sockaddr_broadcast, NULL);
1039
1040 set_timeout_interval(client->interval, send_discover);
1041 }
1042
1043 /*
1044 * state_panic gets called if we haven't received any offers in a preset
1045 * amount of time. When this happens, we try to use existing leases
1046 * that haven't yet expired, and failing that, we call the client script
1047 * and hope it can do something.
1048 */
1049 void
state_panic(void)1050 state_panic(void)
1051 {
1052 struct client_lease *loop = client->active;
1053 struct client_lease *lp;
1054 time_t cur_time;
1055
1056 note("No DHCPOFFERS received.");
1057
1058 /* We may not have an active lease, but we may have some
1059 predefined leases that we can try. */
1060 if (!client->active && client->leases)
1061 goto activate_next;
1062
1063 /* Run through the list of leases and see if one can be used. */
1064 time(&cur_time);
1065 while (client->active) {
1066 if (client->active->expiry > cur_time) {
1067 note("Trying recorded lease %s",
1068 piaddr(client->active->address));
1069 /* Run the client script with the existing
1070 parameters. */
1071 script_init("TIMEOUT");
1072 script_write_params("new_", client->active);
1073
1074 /* If the old lease is still good and doesn't
1075 yet need renewal, go into BOUND state and
1076 timeout at the renewal time. */
1077 if (!script_go()) {
1078 if (cur_time < client->active->renewal) {
1079 client->state = S_BOUND;
1080 note("bound: renewal in %lld seconds.",
1081 (long long)(client->active->renewal
1082 - cur_time));
1083 set_timeout(client->active->renewal,
1084 state_bound);
1085 } else {
1086 client->state = S_BOUND;
1087 note("bound: immediate renewal.");
1088 state_bound();
1089 }
1090 return;
1091 }
1092 }
1093
1094 /* If there are no other leases, give up. */
1095 if (!client->leases) {
1096 client->leases = client->active;
1097 client->active = NULL;
1098 break;
1099 }
1100
1101 activate_next:
1102 /* Otherwise, put the active lease at the end of the
1103 lease list, and try another lease.. */
1104 for (lp = client->leases; lp->next; lp = lp->next)
1105 ;
1106 lp->next = client->active;
1107 if (lp->next)
1108 lp->next->next = NULL;
1109 client->active = client->leases;
1110 client->leases = client->leases->next;
1111
1112 /* If we already tried this lease, we've exhausted the
1113 set of leases, so we might as well give up for
1114 now. */
1115 if (client->active == loop)
1116 break;
1117 else if (!loop)
1118 loop = client->active;
1119 }
1120
1121 /* No leases were available, or what was available didn't work, so
1122 tell the shell script that we failed to allocate an address,
1123 and try again later. */
1124 note("No working leases in persistent database - sleeping.");
1125 script_init("FAIL");
1126 script_go();
1127 client->state = S_INIT;
1128 set_timeout_interval(config->retry_interval, state_init);
1129 }
1130
1131 void
send_request(void)1132 send_request(void)
1133 {
1134 struct sockaddr_in destination;
1135 struct in_addr from;
1136 time_t cur_time;
1137 int interval;
1138
1139 time(&cur_time);
1140
1141 /* Figure out how long it's been since we started transmitting. */
1142 interval = (int)(cur_time - client->first_sending);
1143
1144 /* If we're in the INIT-REBOOT or REQUESTING state and we're
1145 past the reboot timeout, go to INIT and see if we can
1146 DISCOVER an address... */
1147 /* XXX In the INIT-REBOOT state, if we don't get an ACK, it
1148 means either that we're on a network with no DHCP server,
1149 or that our server is down. In the latter case, assuming
1150 that there is a backup DHCP server, DHCPDISCOVER will get
1151 us a new address, but we could also have successfully
1152 reused our old address. In the former case, we're hosed
1153 anyway. This is not a win-prone situation. */
1154 if ((client->state == S_REBOOTING ||
1155 client->state == S_REQUESTING) &&
1156 interval > config->reboot_timeout) {
1157 client->state = S_INIT;
1158 cancel_timeout();
1159 state_init();
1160 return;
1161 }
1162
1163 /* If the lease has expired, relinquish the address and go back
1164 to the INIT state. */
1165 if (client->state != S_REQUESTING &&
1166 cur_time > client->active->expiry) {
1167 /* Run the client script with the new parameters. */
1168 script_init("EXPIRE");
1169 script_write_params("old_", client->active);
1170 script_go();
1171
1172 client->state = S_INIT;
1173 state_init();
1174 return;
1175 }
1176
1177 /* Do the exponential backoff... */
1178 if (!client->interval)
1179 client->interval = config->initial_interval;
1180 else
1181 client->interval += ((arc4random() >> 2) %
1182 (2 * client->interval));
1183
1184 /* Don't backoff past cutoff. */
1185 if (client->interval > config->backoff_cutoff)
1186 client->interval = ((config->backoff_cutoff / 2) +
1187 ((arc4random() >> 2) % client->interval));
1188
1189 /* If the backoff would take us to the expiry time, just set the
1190 timeout to the expiry time. */
1191 if (client->state != S_REQUESTING && cur_time + client->interval >
1192 client->active->expiry)
1193 client->interval = client->active->expiry - cur_time + 1;
1194
1195 /* If the lease T2 time has elapsed, or if we're not yet bound,
1196 broadcast the DHCPREQUEST rather than unicasting. */
1197 memset(&destination, 0, sizeof(destination));
1198 if (client->state == S_REQUESTING ||
1199 client->state == S_REBOOTING ||
1200 cur_time > client->active->rebind)
1201 destination.sin_addr.s_addr = INADDR_BROADCAST;
1202 else
1203 memcpy(&destination.sin_addr.s_addr, client->destination.iabuf,
1204 sizeof(destination.sin_addr.s_addr));
1205 destination.sin_port = htons(REMOTE_PORT);
1206 destination.sin_family = AF_INET;
1207 destination.sin_len = sizeof(destination);
1208
1209 if (client->state != S_REQUESTING)
1210 memcpy(&from, client->active->address.iabuf, sizeof(from));
1211 else
1212 from.s_addr = INADDR_ANY;
1213
1214 /* Record the number of seconds since we started sending. */
1215 if (client->state == S_REQUESTING)
1216 client->packet.secs = client->secs;
1217 else {
1218 if (interval < 65536)
1219 client->packet.secs = htons(interval);
1220 else
1221 client->packet.secs = htons(65535);
1222 }
1223
1224 note("DHCPREQUEST on %s to %s port %d", ifi->name,
1225 inet_ntoa(destination.sin_addr), ntohs(destination.sin_port));
1226
1227 send_packet(from, &destination, NULL);
1228
1229 set_timeout_interval(client->interval, send_request);
1230 }
1231
1232 void
send_decline(void)1233 send_decline(void)
1234 {
1235 note("DHCPDECLINE on %s to %s port %d", ifi->name,
1236 inet_ntoa(sockaddr_broadcast.sin_addr),
1237 ntohs(sockaddr_broadcast.sin_port));
1238
1239 send_packet(inaddr_any, &sockaddr_broadcast, NULL);
1240 }
1241
1242 void
make_discover(struct client_lease * lease)1243 make_discover(struct client_lease *lease)
1244 {
1245 unsigned char discover = DHCPDISCOVER;
1246 struct option_data options[256];
1247 int i;
1248
1249 memset(options, 0, sizeof(options));
1250 memset(&client->packet, 0, sizeof(client->packet));
1251
1252 /* Set DHCP_MESSAGE_TYPE to DHCPDISCOVER */
1253 i = DHO_DHCP_MESSAGE_TYPE;
1254 options[i].data = &discover;
1255 options[i].len = sizeof(discover);
1256
1257 /* Request the options we want */
1258 i = DHO_DHCP_PARAMETER_REQUEST_LIST;
1259 options[i].data = config->requested_options;
1260 options[i].len = config->requested_option_count;
1261
1262 /* If we had an address, try to get it again. */
1263 if (lease) {
1264 client->requested_address = lease->address;
1265 i = DHO_DHCP_REQUESTED_ADDRESS;
1266 options[i].data = lease->address.iabuf;
1267 options[i].len = lease->address.len;
1268 } else
1269 client->requested_address.len = 0;
1270
1271 /* Send any options requested in the config file. */
1272 for (i = 0; i < 256; i++)
1273 if (!options[i].data &&
1274 config->send_options[i].data) {
1275 options[i].data = config->send_options[i].data;
1276 options[i].len = config->send_options[i].len;
1277 }
1278
1279 /* Set up the option buffer to fit in a minimal UDP packet. */
1280 i = cons_options(options);
1281 if (i == -1 || client->packet.options[i] != DHO_END)
1282 error("options do not fit in DHCPDISCOVER packet.");
1283 client->packet_length = DHCP_FIXED_NON_UDP+i+1;
1284 if (client->packet_length < BOOTP_MIN_LEN)
1285 client->packet_length = BOOTP_MIN_LEN;
1286
1287 client->packet.op = BOOTREQUEST;
1288 client->packet.htype = ifi->hw_address.htype;
1289 client->packet.hlen = ifi->hw_address.hlen;
1290 client->packet.hops = 0;
1291 client->packet.xid = arc4random();
1292 client->packet.secs = 0; /* filled in by send_discover. */
1293 client->packet.flags = 0;
1294
1295 memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr));
1296 memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr));
1297 memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr));
1298 memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr));
1299 memcpy(client->packet.chaddr, ifi->hw_address.haddr,
1300 ifi->hw_address.hlen);
1301 }
1302
1303 void
make_request(struct client_lease * lease)1304 make_request(struct client_lease * lease)
1305 {
1306 unsigned char request = DHCPREQUEST;
1307 struct option_data options[256];
1308 int i;
1309
1310 memset(options, 0, sizeof(options));
1311 memset(&client->packet, 0, sizeof(client->packet));
1312
1313 /* Set DHCP_MESSAGE_TYPE to DHCPREQUEST */
1314 i = DHO_DHCP_MESSAGE_TYPE;
1315 options[i].data = &request;
1316 options[i].len = sizeof(request);
1317
1318 /* Request the options we want */
1319 i = DHO_DHCP_PARAMETER_REQUEST_LIST;
1320 options[i].data = config->requested_options;
1321 options[i].len = config->requested_option_count;
1322
1323 /* If we are requesting an address that hasn't yet been assigned
1324 to us, use the DHCP Requested Address option. */
1325 if (client->state == S_REQUESTING) {
1326 /* Send back the server identifier... */
1327 i = DHO_DHCP_SERVER_IDENTIFIER;
1328 options[i].data = lease->options[i].data;
1329 options[i].len = lease->options[i].len;
1330 }
1331 if (client->state == S_REQUESTING ||
1332 client->state == S_REBOOTING) {
1333 client->requested_address = lease->address;
1334 i = DHO_DHCP_REQUESTED_ADDRESS;
1335 options[i].data = lease->address.iabuf;
1336 options[i].len = lease->address.len;
1337 } else
1338 client->requested_address.len = 0;
1339
1340 /* Send any options requested in the config file. */
1341 for (i = 0; i < 256; i++)
1342 if (!options[i].data && config->send_options[i].data) {
1343 options[i].data = config->send_options[i].data;
1344 options[i].len = config->send_options[i].len;
1345 }
1346
1347 /* Set up the option buffer to fit in a minimal UDP packet. */
1348 i = cons_options(options);
1349 if (i == -1 || client->packet.options[i] != DHO_END)
1350 error("options do not fit in DHCPREQUEST packet.");
1351 client->packet_length = DHCP_FIXED_NON_UDP+i+1;
1352 if (client->packet_length < BOOTP_MIN_LEN)
1353 client->packet_length = BOOTP_MIN_LEN;
1354
1355 client->packet.op = BOOTREQUEST;
1356 client->packet.htype = ifi->hw_address.htype;
1357 client->packet.hlen = ifi->hw_address.hlen;
1358 client->packet.hops = 0;
1359 client->packet.xid = client->xid;
1360 client->packet.secs = 0; /* Filled in by send_request. */
1361 client->packet.flags = 0;
1362
1363 /* If we own the address we're requesting, put it in ciaddr;
1364 otherwise set ciaddr to zero. */
1365 if (client->state == S_BOUND ||
1366 client->state == S_RENEWING ||
1367 client->state == S_REBINDING) {
1368 memcpy(&client->packet.ciaddr,
1369 lease->address.iabuf, lease->address.len);
1370 } else {
1371 memset(&client->packet.ciaddr, 0,
1372 sizeof(client->packet.ciaddr));
1373 }
1374
1375 memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr));
1376 memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr));
1377 memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr));
1378 memcpy(client->packet.chaddr, ifi->hw_address.haddr,
1379 ifi->hw_address.hlen);
1380 }
1381
1382 void
make_decline(struct client_lease * lease)1383 make_decline(struct client_lease *lease)
1384 {
1385 struct option_data options[256];
1386 unsigned char decline = DHCPDECLINE;
1387 int i;
1388
1389 memset(options, 0, sizeof(options));
1390 memset(&client->packet, 0, sizeof(client->packet));
1391
1392 /* Set DHCP_MESSAGE_TYPE to DHCPDECLINE */
1393 i = DHO_DHCP_MESSAGE_TYPE;
1394 options[i].data = &decline;
1395 options[i].len = sizeof(decline);
1396
1397 /* Send back the server identifier... */
1398 i = DHO_DHCP_SERVER_IDENTIFIER;
1399 options[i].data = lease->options[i].data;
1400 options[i].len = lease->options[i].len;
1401
1402 /* Send back the address we're declining. */
1403 i = DHO_DHCP_REQUESTED_ADDRESS;
1404 options[i].data = lease->address.iabuf;
1405 options[i].len = lease->address.len;
1406
1407 /* Send the uid if the user supplied one. */
1408 i = DHO_DHCP_CLIENT_IDENTIFIER;
1409 if (config->send_options[i].len) {
1410 options[i].data = config->send_options[i].data;
1411 options[i].len = config->send_options[i].len;
1412 }
1413
1414 /* Set up the option buffer to fit in a minimal UDP packet. */
1415 i = cons_options(options);
1416 if (i == -1 || client->packet.options[i] != DHO_END)
1417 error("options do not fit in DHCPDECLINE packet.");
1418 client->packet_length = DHCP_FIXED_NON_UDP+i+1;
1419 if (client->packet_length < BOOTP_MIN_LEN)
1420 client->packet_length = BOOTP_MIN_LEN;
1421
1422 client->packet.op = BOOTREQUEST;
1423 client->packet.htype = ifi->hw_address.htype;
1424 client->packet.hlen = ifi->hw_address.hlen;
1425 client->packet.hops = 0;
1426 client->packet.xid = client->xid;
1427 client->packet.secs = 0; /* Filled in by send_request. */
1428 client->packet.flags = 0;
1429
1430 /* ciaddr must always be zero. */
1431 memset(&client->packet.ciaddr, 0, sizeof(client->packet.ciaddr));
1432 memset(&client->packet.yiaddr, 0, sizeof(client->packet.yiaddr));
1433 memset(&client->packet.siaddr, 0, sizeof(client->packet.siaddr));
1434 memset(&client->packet.giaddr, 0, sizeof(client->packet.giaddr));
1435 memcpy(client->packet.chaddr, ifi->hw_address.haddr,
1436 ifi->hw_address.hlen);
1437 }
1438
1439 void
free_client_lease(struct client_lease * lease)1440 free_client_lease(struct client_lease *lease)
1441 {
1442 int i;
1443
1444 if (lease->server_name)
1445 free(lease->server_name);
1446 if (lease->filename)
1447 free(lease->filename);
1448 for (i = 0; i < 256; i++) {
1449 if (lease->options[i].len)
1450 free(lease->options[i].data);
1451 }
1452 free(lease);
1453 }
1454
1455 void
rewrite_client_leases(void)1456 rewrite_client_leases(void)
1457 {
1458 struct client_lease *lp;
1459
1460 if (!leaseFile) /* XXX */
1461 error("lease file not open");
1462
1463 fflush(leaseFile);
1464 rewind(leaseFile);
1465
1466 for (lp = client->leases; lp; lp = lp->next) {
1467 if (client->active && addr_eq(lp->address,
1468 client->active->address))
1469 continue;
1470 write_client_lease(lp);
1471 }
1472
1473 if (client->active)
1474 write_client_lease(client->active);
1475
1476 fflush(leaseFile);
1477 ftruncate(fileno(leaseFile), ftello(leaseFile));
1478 fsync(fileno(leaseFile));
1479 }
1480
1481 void
write_client_lease(struct client_lease * lease)1482 write_client_lease(struct client_lease *lease)
1483 {
1484 struct tm *t;
1485 int i;
1486
1487 /* If the lease came from the config file, we don't need to stash
1488 a copy in the lease database. */
1489 if (lease->is_static)
1490 return;
1491
1492 if (!leaseFile) /* XXX */
1493 error("lease file not open");
1494
1495 fprintf(leaseFile, "lease {\n");
1496 if (lease->is_bootp)
1497 fprintf(leaseFile, " bootp;\n");
1498 fprintf(leaseFile, " interface \"%s\";\n", ifi->name);
1499 fprintf(leaseFile, " fixed-address %s;\n", piaddr(lease->address));
1500 if (lease->filename)
1501 fprintf(leaseFile, " filename \"%s\";\n", lease->filename);
1502 if (lease->server_name)
1503 fprintf(leaseFile, " server-name \"%s\";\n",
1504 lease->server_name);
1505 for (i = 0; i < 256; i++)
1506 if (lease->options[i].len)
1507 fprintf(leaseFile, " option %s %s;\n",
1508 dhcp_options[i].name,
1509 pretty_print_option(i, &lease->options[i], 1));
1510
1511 t = gmtime(&lease->renewal);
1512 fprintf(leaseFile, " renew %d %d/%d/%d %02d:%02d:%02d;\n",
1513 t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
1514 t->tm_hour, t->tm_min, t->tm_sec);
1515 t = gmtime(&lease->rebind);
1516 fprintf(leaseFile, " rebind %d %d/%d/%d %02d:%02d:%02d;\n",
1517 t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
1518 t->tm_hour, t->tm_min, t->tm_sec);
1519 t = gmtime(&lease->expiry);
1520 fprintf(leaseFile, " expire %d %d/%d/%d %02d:%02d:%02d;\n",
1521 t->tm_wday, t->tm_year + 1900, t->tm_mon + 1, t->tm_mday,
1522 t->tm_hour, t->tm_min, t->tm_sec);
1523 fprintf(leaseFile, "}\n");
1524 fflush(leaseFile);
1525 }
1526
1527 void
script_init(char * reason)1528 script_init(char *reason)
1529 {
1530 size_t len;
1531 struct imsg_hdr hdr;
1532 struct buf *buf;
1533
1534 hdr.code = IMSG_SCRIPT_INIT;
1535 hdr.len = sizeof(struct imsg_hdr) + sizeof(size_t) + strlen(reason);
1536 buf = buf_open(hdr.len);
1537
1538 buf_add(buf, &hdr, sizeof(hdr));
1539 len = strlen(reason);
1540 buf_add(buf, &len, sizeof(len));
1541 buf_add(buf, reason, len);
1542
1543 buf_close(privfd, buf);
1544 }
1545
1546 void
priv_script_init(char * reason)1547 priv_script_init(char *reason)
1548 {
1549 client->scriptEnvsize = 100;
1550 if (client->scriptEnv == NULL)
1551 client->scriptEnv =
1552 calloc(client->scriptEnvsize, sizeof(char *));
1553 if (client->scriptEnv == NULL)
1554 error("script_init: no memory for environment");
1555
1556 client->scriptEnv[0] = strdup(CLIENT_PATH);
1557 if (client->scriptEnv[0] == NULL)
1558 error("script_init: no memory for environment");
1559
1560 client->scriptEnv[1] = NULL;
1561
1562 script_set_env("", "interface", ifi->name);
1563
1564 script_set_env("", "reason", reason);
1565 }
1566
1567 void
priv_script_write_params(char * prefix,struct client_lease * lease)1568 priv_script_write_params(char *prefix, struct client_lease *lease)
1569 {
1570 char buf[256];
1571 struct option_data o;
1572 int i;
1573
1574 script_set_env(prefix, "ip_address", piaddr(lease->address));
1575
1576 if (lease->options[DHO_SUBNET_MASK].len &&
1577 (lease->options[DHO_SUBNET_MASK].len <
1578 sizeof(lease->address.iabuf))) {
1579 struct iaddr netmask, subnet, broadcast;
1580
1581 memcpy(netmask.iabuf, lease->options[DHO_SUBNET_MASK].data,
1582 lease->options[DHO_SUBNET_MASK].len);
1583 netmask.len = lease->options[DHO_SUBNET_MASK].len;
1584
1585 subnet = subnet_number(lease->address, netmask);
1586 if (subnet.len) {
1587 script_set_env(prefix, "network_number",
1588 piaddr(subnet));
1589 if (!lease->options[DHO_BROADCAST_ADDRESS].len) {
1590 broadcast = broadcast_addr(subnet, netmask);
1591 if (broadcast.len)
1592 script_set_env(prefix,
1593 "broadcast_address",
1594 piaddr(broadcast));
1595 }
1596 }
1597 }
1598
1599 if (lease->filename)
1600 script_set_env(prefix, "filename", lease->filename);
1601 if (lease->server_name)
1602 script_set_env(prefix, "server_name",
1603 lease->server_name);
1604
1605 for (i = 0; i < 256; i++) {
1606 if (!dhcp_option_ev_name(buf, sizeof(buf), &dhcp_options[i]))
1607 continue;
1608
1609 switch (config->default_actions[i]) {
1610 case ACTION_IGNORE:
1611 break;
1612
1613 case ACTION_DEFAULT:
1614 if (lease->options[i].len)
1615 script_set_env(prefix, buf,
1616 pretty_print_option(i, &lease->options[i],
1617 0));
1618 else if (config->defaults[i].len)
1619 script_set_env(prefix, buf,
1620 pretty_print_option(i, &config->defaults[i],
1621 0));
1622 break;
1623
1624 case ACTION_SUPERSEDE:
1625 if (config->defaults[i].len)
1626 script_set_env(prefix, buf,
1627 pretty_print_option(i, &config->defaults[i],
1628 0));
1629 break;
1630
1631 case ACTION_PREPEND:
1632 o.len = config->defaults[i].len + lease->options[i].len;
1633 if (o.len > 0) {
1634 o.data = calloc(1, o.len);
1635 if (o.data == NULL)
1636 error("no space to prepend '%s' to %s",
1637 config->defaults[i].data,
1638 dhcp_options[i].name);
1639 memcpy(o.data, config->defaults[i].data,
1640 config->defaults[i].len);
1641 memcpy(o.data + config->defaults[i].len,
1642 lease->options[i].data,
1643 lease->options[i].len);
1644 script_set_env(prefix, buf,
1645 pretty_print_option(i, &o, 0));
1646 free(o.data);
1647 }
1648 break;
1649
1650 case ACTION_APPEND:
1651 o.len = config->defaults[i].len + lease->options[i].len;
1652 if (o.len > 0) {
1653 o.data = calloc(1, o.len);
1654 if (o.data == NULL)
1655 error("no space to append '%s' to %s",
1656 config->defaults[i].data,
1657 dhcp_options[i].name);
1658 memcpy(o.data, lease->options[i].data,
1659 lease->options[i].len);
1660 memcpy(o.data + lease->options[i].len,
1661 config->defaults[i].data,
1662 config->defaults[i].len);
1663 script_set_env(prefix, buf,
1664 pretty_print_option(i, &o, 0));
1665 free(o.data);
1666 }
1667 break;
1668 }
1669 }
1670
1671 snprintf(buf, sizeof(buf), "%d", (int)lease->expiry);
1672 script_set_env(prefix, "expiry", buf);
1673 }
1674
1675 void
script_write_params(char * prefix,struct client_lease * lease)1676 script_write_params(char *prefix, struct client_lease *lease)
1677 {
1678 size_t fn_len = 0, sn_len = 0, pr_len = 0;
1679 struct imsg_hdr hdr;
1680 struct buf *buf;
1681 int i;
1682
1683 if (lease->filename != NULL)
1684 fn_len = strlen(lease->filename);
1685 if (lease->server_name != NULL)
1686 sn_len = strlen(lease->server_name);
1687 if (prefix != NULL)
1688 pr_len = strlen(prefix);
1689
1690 hdr.code = IMSG_SCRIPT_WRITE_PARAMS;
1691 hdr.len = sizeof(hdr) + sizeof(struct client_lease) +
1692 sizeof(size_t) + fn_len + sizeof(size_t) + sn_len +
1693 sizeof(size_t) + pr_len;
1694
1695 for (i = 0; i < 256; i++)
1696 hdr.len += sizeof(int) + lease->options[i].len;
1697
1698 scripttime = time(NULL);
1699
1700 buf = buf_open(hdr.len);
1701
1702 buf_add(buf, &hdr, sizeof(hdr));
1703 buf_add(buf, lease, sizeof(struct client_lease));
1704 buf_add(buf, &fn_len, sizeof(fn_len));
1705 buf_add(buf, lease->filename, fn_len);
1706 buf_add(buf, &sn_len, sizeof(sn_len));
1707 buf_add(buf, lease->server_name, sn_len);
1708 buf_add(buf, &pr_len, sizeof(pr_len));
1709 buf_add(buf, prefix, pr_len);
1710
1711 for (i = 0; i < 256; i++) {
1712 buf_add(buf, &lease->options[i].len,
1713 sizeof(lease->options[i].len));
1714 buf_add(buf, lease->options[i].data,
1715 lease->options[i].len);
1716 }
1717
1718 buf_close(privfd, buf);
1719 }
1720
1721 int
script_go(void)1722 script_go(void)
1723 {
1724 struct imsg_hdr hdr;
1725 struct buf *buf;
1726 int ret;
1727
1728 scripttime = time(NULL);
1729
1730 hdr.code = IMSG_SCRIPT_GO;
1731 hdr.len = sizeof(struct imsg_hdr);
1732
1733 buf = buf_open(hdr.len);
1734
1735 buf_add(buf, &hdr, sizeof(hdr));
1736 buf_close(privfd, buf);
1737
1738 bzero(&hdr, sizeof(hdr));
1739 buf_read(privfd, &hdr, sizeof(hdr));
1740 if (hdr.code != IMSG_SCRIPT_GO_RET)
1741 error("unexpected msg type %u", hdr.code);
1742 if (hdr.len != sizeof(hdr) + sizeof(int))
1743 error("received corrupted message");
1744 buf_read(privfd, &ret, sizeof(ret));
1745
1746 return (ret);
1747 }
1748
1749 int
priv_script_go(void)1750 priv_script_go(void)
1751 {
1752 char *scriptName, *argv[2], **envp;
1753 int pid, wpid, wstatus;
1754
1755 scripttime = time(NULL);
1756
1757 scriptName = config->script_name;
1758 envp = client->scriptEnv;
1759
1760 argv[0] = scriptName;
1761 argv[1] = NULL;
1762
1763 pid = fork();
1764 if (pid < 0) {
1765 error("fork: %m");
1766 } else if (pid) {
1767 do {
1768 wpid = wait(&wstatus);
1769 } while (wpid != pid && wpid > 0);
1770 if (wpid < 0) {
1771 error("wait: %m");
1772 }
1773 } else {
1774 execve(scriptName, argv, envp);
1775 error("execve (%s, ...): %m", scriptName);
1776 }
1777
1778 script_flush_env();
1779
1780 return (WEXITSTATUS(wstatus));
1781 }
1782
1783 void
script_set_env(const char * prefix,const char * name,const char * value)1784 script_set_env(const char *prefix, const char *name, const char *value)
1785 {
1786 int i, j, namelen;
1787
1788 /* No `` or $() command substitution allowed in environment values! */
1789 for (j = 0; j < strlen(value); j++)
1790 switch (value[j]) {
1791 case '`':
1792 case '$':
1793 warning("illegal character (%c) in value '%s'",
1794 value[j], value);
1795 /* Ignore this option */
1796 return;
1797 }
1798
1799 namelen = strlen(name);
1800
1801 for (i = 0; client->scriptEnv[i]; i++)
1802 if (strncmp(client->scriptEnv[i], name, namelen) == 0 &&
1803 client->scriptEnv[i][namelen] == '=')
1804 break;
1805
1806 if (client->scriptEnv[i])
1807 /* Reuse the slot. */
1808 free(client->scriptEnv[i]);
1809 else {
1810 /* New variable. Expand if necessary. */
1811 if (i >= client->scriptEnvsize - 1) {
1812 char **newscriptEnv;
1813 int newscriptEnvsize = client->scriptEnvsize + 50;
1814
1815 newscriptEnv = realloc(client->scriptEnv,
1816 newscriptEnvsize);
1817 if (newscriptEnv == NULL) {
1818 free(client->scriptEnv);
1819 client->scriptEnv = NULL;
1820 client->scriptEnvsize = 0;
1821 error("script_set_env: no memory for variable");
1822 }
1823 client->scriptEnv = newscriptEnv;
1824 client->scriptEnvsize = newscriptEnvsize;
1825 }
1826 /* need to set the NULL pointer at end of array beyond
1827 the new slot. */
1828 client->scriptEnv[i + 1] = NULL;
1829 }
1830 /* Allocate space and format the variable in the appropriate slot. */
1831 client->scriptEnv[i] = malloc(strlen(prefix) + strlen(name) + 1 +
1832 strlen(value) + 1);
1833 if (client->scriptEnv[i] == NULL)
1834 error("script_set_env: no memory for variable assignment");
1835 snprintf(client->scriptEnv[i], strlen(prefix) + strlen(name) +
1836 1 + strlen(value) + 1, "%s%s=%s", prefix, name, value);
1837 }
1838
1839 void
script_flush_env(void)1840 script_flush_env(void)
1841 {
1842 int i;
1843
1844 for (i = 0; client->scriptEnv[i]; i++) {
1845 free(client->scriptEnv[i]);
1846 client->scriptEnv[i] = NULL;
1847 }
1848 client->scriptEnvsize = 0;
1849 }
1850
1851 int
dhcp_option_ev_name(char * buf,size_t buflen,const struct option * option)1852 dhcp_option_ev_name(char *buf, size_t buflen, const struct option *option)
1853 {
1854 size_t i;
1855
1856 for (i = 0; option->name[i]; i++) {
1857 if (i + 1 == buflen)
1858 return 0;
1859 if (option->name[i] == '-')
1860 buf[i] = '_';
1861 else
1862 buf[i] = option->name[i];
1863 }
1864
1865 buf[i] = 0;
1866 return 1;
1867 }
1868
1869 void
go_daemon(void)1870 go_daemon(void)
1871 {
1872 char buf[256];
1873 int fd;
1874
1875 /*
1876 * Only once
1877 */
1878 if (no_daemon == 2)
1879 return;
1880
1881 /*
1882 * Setup pidfile, kill any dhclient already running for this
1883 * interface.
1884 */
1885 snprintf(buf, sizeof(buf), "/var/run/dhclient.%s.pid", orig_ifname);
1886 fd = open(buf, O_RDWR|O_CREAT, 0644);
1887 if (fd >= 0) {
1888 if (killclient(fd)) {
1889 fprintf(stderr,
1890 "starting dhclient on %s\n",
1891 orig_ifname);
1892 } else {
1893 fprintf(stderr,
1894 "restarting dhclient on %s\n",
1895 orig_ifname);
1896 }
1897 }
1898
1899 /*
1900 * Daemonize if requested
1901 */
1902 if (no_daemon == 0) {
1903 /* Stop logging to stderr... */
1904 log_perror = 0;
1905
1906 if (daemon(1, 0) == -1)
1907 error("daemon");
1908
1909 /* we are chrooted, daemon(3) fails to open /dev/null */
1910 if (nullfd != -1) {
1911 dup2(nullfd, STDIN_FILENO);
1912 dup2(nullfd, STDOUT_FILENO);
1913 dup2(nullfd, STDERR_FILENO);
1914 close(nullfd);
1915 nullfd = -1;
1916 }
1917 }
1918
1919 /*
1920 * No further daemonizations, write out pid file and lock.
1921 */
1922 no_daemon = 2;
1923 if (fd >= 0) {
1924 lseek(fd, 0L, SEEK_SET);
1925 ftruncate(fd, 0);
1926 snprintf(buf, sizeof(buf), "%ld\n", (long)getpid());
1927 write(fd, buf, strlen(buf));
1928 flock(fd, LOCK_EX);
1929 /* leave descriptor open and locked */
1930 }
1931 }
1932
1933 int
check_option(struct client_lease * l,int option)1934 check_option(struct client_lease *l, int option)
1935 {
1936 char *opbuf;
1937 char *sbuf;
1938
1939 /* we use this, since this is what gets passed to dhclient-script */
1940
1941 opbuf = pretty_print_option(option, &l->options[option], 0);
1942
1943 sbuf = option_as_string(option, l->options[option].data,
1944 l->options[option].len);
1945
1946 switch (option) {
1947 case DHO_SUBNET_MASK:
1948 case DHO_SWAP_SERVER:
1949 case DHO_BROADCAST_ADDRESS:
1950 case DHO_DHCP_SERVER_IDENTIFIER:
1951 case DHO_ROUTER_SOLICITATION_ADDRESS:
1952 case DHO_DHCP_REQUESTED_ADDRESS:
1953 if (ipv4addrs(opbuf) == 0) {
1954 warning("Invalid IP address in option %s: %s",
1955 dhcp_options[option].name, opbuf);
1956 return (0);
1957 }
1958 if (l->options[option].len != 4) { /* RFC 2132 */
1959 warning("warning: Only 1 IP address allowed in "
1960 "%s option; length %d, must be 4",
1961 dhcp_options[option].name,
1962 l->options[option].len);
1963 l->options[option].len = 4;
1964 }
1965 return (1);
1966 case DHO_TIME_SERVERS:
1967 case DHO_NAME_SERVERS:
1968 case DHO_ROUTERS:
1969 case DHO_DOMAIN_NAME_SERVERS:
1970 case DHO_LOG_SERVERS:
1971 case DHO_COOKIE_SERVERS:
1972 case DHO_LPR_SERVERS:
1973 case DHO_IMPRESS_SERVERS:
1974 case DHO_RESOURCE_LOCATION_SERVERS:
1975 case DHO_NIS_SERVERS:
1976 case DHO_NTP_SERVERS:
1977 case DHO_NETBIOS_NAME_SERVERS:
1978 case DHO_NETBIOS_DD_SERVER:
1979 case DHO_FONT_SERVERS:
1980 if (ipv4addrs(opbuf) == 0) {
1981 warning("Invalid IP address in option %s: %s",
1982 dhcp_options[option].name, opbuf);
1983 return (0);
1984 }
1985 return (1);
1986 case DHO_HOST_NAME:
1987 case DHO_DOMAIN_NAME:
1988 case DHO_NIS_DOMAIN:
1989 if (!res_hnok(sbuf)) {
1990 warning("Bogus Host Name option %d: %s (%s)", option,
1991 sbuf, opbuf);
1992 l->options[option].len = 0;
1993 free(l->options[option].data);
1994 }
1995 return (1);
1996 case DHO_PAD:
1997 case DHO_TIME_OFFSET:
1998 case DHO_BOOT_SIZE:
1999 case DHO_MERIT_DUMP:
2000 case DHO_ROOT_PATH:
2001 case DHO_EXTENSIONS_PATH:
2002 case DHO_IP_FORWARDING:
2003 case DHO_NON_LOCAL_SOURCE_ROUTING:
2004 case DHO_POLICY_FILTER:
2005 case DHO_MAX_DGRAM_REASSEMBLY:
2006 case DHO_DEFAULT_IP_TTL:
2007 case DHO_PATH_MTU_AGING_TIMEOUT:
2008 case DHO_PATH_MTU_PLATEAU_TABLE:
2009 case DHO_INTERFACE_MTU:
2010 case DHO_ALL_SUBNETS_LOCAL:
2011 case DHO_PERFORM_MASK_DISCOVERY:
2012 case DHO_MASK_SUPPLIER:
2013 case DHO_ROUTER_DISCOVERY:
2014 case DHO_STATIC_ROUTES:
2015 case DHO_TRAILER_ENCAPSULATION:
2016 case DHO_ARP_CACHE_TIMEOUT:
2017 case DHO_IEEE802_3_ENCAPSULATION:
2018 case DHO_DEFAULT_TCP_TTL:
2019 case DHO_TCP_KEEPALIVE_INTERVAL:
2020 case DHO_TCP_KEEPALIVE_GARBAGE:
2021 case DHO_VENDOR_ENCAPSULATED_OPTIONS:
2022 case DHO_NETBIOS_NODE_TYPE:
2023 case DHO_NETBIOS_SCOPE:
2024 case DHO_X_DISPLAY_MANAGER:
2025 case DHO_DHCP_LEASE_TIME:
2026 case DHO_DHCP_OPTION_OVERLOAD:
2027 case DHO_DHCP_MESSAGE_TYPE:
2028 case DHO_DHCP_PARAMETER_REQUEST_LIST:
2029 case DHO_DHCP_MESSAGE:
2030 case DHO_DHCP_MAX_MESSAGE_SIZE:
2031 case DHO_DHCP_RENEWAL_TIME:
2032 case DHO_DHCP_REBINDING_TIME:
2033 case DHO_DHCP_CLASS_IDENTIFIER:
2034 case DHO_DHCP_CLIENT_IDENTIFIER:
2035 case DHO_DHCP_USER_CLASS_ID:
2036 case DHO_TFTP_SERVER:
2037 case DHO_END:
2038 return (1);
2039 case DHO_CLASSLESS_ROUTES:
2040 return (check_classless_option(l->options[option].data,
2041 l->options[option].len));
2042 default:
2043 if (!unknown_ok)
2044 warning("unknown dhcp option value 0x%x", option);
2045 return (unknown_ok);
2046 }
2047 }
2048
2049 /* RFC 3442 The Classless Static Routes option checks */
2050 int
check_classless_option(unsigned char * data,int len)2051 check_classless_option(unsigned char *data, int len)
2052 {
2053 int i = 0;
2054 unsigned char width;
2055 in_addr_t addr, mask;
2056
2057 if (len < 5) {
2058 warning("Too small length: %d", len);
2059 return (0);
2060 }
2061 while(i < len) {
2062 width = data[i++];
2063 if (width == 0) {
2064 i += 4;
2065 continue;
2066 } else if (width < 9) {
2067 addr = (in_addr_t)(data[i] << 24);
2068 i += 1;
2069 } else if (width < 17) {
2070 addr = (in_addr_t)(data[i] << 24) +
2071 (in_addr_t)(data[i + 1] << 16);
2072 i += 2;
2073 } else if (width < 25) {
2074 addr = (in_addr_t)(data[i] << 24) +
2075 (in_addr_t)(data[i + 1] << 16) +
2076 (in_addr_t)(data[i + 2] << 8);
2077 i += 3;
2078 } else if (width < 33) {
2079 addr = (in_addr_t)(data[i] << 24) +
2080 (in_addr_t)(data[i + 1] << 16) +
2081 (in_addr_t)(data[i + 2] << 8) +
2082 data[i + 3];
2083 i += 4;
2084 } else {
2085 warning("Incorrect subnet width: %d", width);
2086 return (0);
2087 }
2088 mask = (in_addr_t)(~0) << (32 - width);
2089 addr = ntohl(addr);
2090 mask = ntohl(mask);
2091
2092 /*
2093 * From RFC 3442:
2094 * ... After deriving a subnet number and subnet mask
2095 * from each destination descriptor, the DHCP client
2096 * MUST zero any bits in the subnet number where the
2097 * corresponding bit in the mask is zero...
2098 */
2099 if ((addr & mask) != addr) {
2100 addr &= mask;
2101 data[i - 1] = (unsigned char)(
2102 (addr >> rounddown(32 - width, 8)) & 0xFF);
2103 }
2104 i += 4;
2105 }
2106 if (i > len) {
2107 warning("Incorrect data length: %d (must be %d)", len, i);
2108 return (0);
2109 }
2110 return (1);
2111 }
2112
2113 int
res_hnok(const char * name)2114 res_hnok(const char *name)
2115 {
2116 const char *dn = name;
2117 int pch = '.', ch = *dn++;
2118 int warn = 0;
2119
2120 while (ch != '\0') {
2121 int nch = *dn++;
2122
2123 if (ch == '.') {
2124 ;
2125 } else if (pch == '.' || nch == '.' || nch == '\0') {
2126 if (!isalnum(ch))
2127 return (0);
2128 } else if (!isalnum(ch) && ch != '-' && ch != '_')
2129 return (0);
2130 else if (ch == '_' && warn == 0) {
2131 warning("warning: hostname %s contains an "
2132 "underscore which violates RFC 952", name);
2133 warn++;
2134 }
2135 pch = ch, ch = nch;
2136 }
2137 return (1);
2138 }
2139
2140 /* Does buf consist only of dotted decimal ipv4 addrs?
2141 * return how many if so,
2142 * otherwise, return 0
2143 */
2144 int
ipv4addrs(char * buf)2145 ipv4addrs(char * buf)
2146 {
2147 struct in_addr jnk;
2148 int count = 0;
2149
2150 while (inet_aton(buf, &jnk) == 1){
2151 count++;
2152 while (*buf == '.' || isdigit(*buf))
2153 buf++;
2154 if (*buf == '\0')
2155 return (count);
2156 while (*buf == ' ')
2157 buf++;
2158 }
2159 return (0);
2160 }
2161
2162 char *
option_as_string(unsigned int code,unsigned char * data,int len)2163 option_as_string(unsigned int code, unsigned char *data, int len)
2164 {
2165 static char optbuf[32768]; /* XXX */
2166 char *op = optbuf;
2167 int opleft = sizeof(optbuf);
2168 unsigned char *dp = data;
2169
2170 if (code > 255)
2171 error("option_as_string: bad code %d", code);
2172
2173 for (; dp < data + len; dp++) {
2174 if (!isascii(*dp) || !isprint(*dp)) {
2175 if (dp + 1 != data + len || *dp != 0) {
2176 size_t oplen;
2177 snprintf(op, opleft, "\\%03o", *dp);
2178 oplen = strlen(op);
2179 op += oplen;
2180 opleft -= oplen;
2181 }
2182 } else if (*dp == '"' || *dp == '\'' || *dp == '$' ||
2183 *dp == '`' || *dp == '\\') {
2184 *op++ = '\\';
2185 *op++ = *dp;
2186 opleft -= 2;
2187 } else {
2188 *op++ = *dp;
2189 opleft--;
2190 }
2191 }
2192 if (opleft < 1)
2193 goto toobig;
2194 *op = 0;
2195 return optbuf;
2196 toobig:
2197 warning("dhcp option too large");
2198 return "<error>";
2199 }
2200
2201 int
fork_privchld(int fd,int fd2)2202 fork_privchld(int fd, int fd2)
2203 {
2204 struct pollfd pfd[1];
2205 int nfds, pfail = 0;
2206 pid_t pid;
2207 int omask;
2208
2209 omask = sigblock(sigmask(SIGINT)|sigmask(SIGHUP));
2210 pid = fork();
2211 if (pid > 0)
2212 monitor_pid = pid;
2213 sigsetmask(omask);
2214
2215 switch (pid) {
2216 case -1:
2217 error("cannot fork");
2218 break;
2219 case 0:
2220 break;
2221 default:
2222 return (0);
2223 }
2224
2225 if (chdir("/") == -1)
2226 error("chdir(\"/\")");
2227
2228 setproctitle("%s [priv]", ifi->name);
2229
2230 dup2(nullfd, STDIN_FILENO);
2231 dup2(nullfd, STDOUT_FILENO);
2232 dup2(nullfd, STDERR_FILENO);
2233 close(nullfd);
2234 close(fd2);
2235
2236 for (;;) {
2237 pfd[0].fd = fd;
2238 pfd[0].events = POLLIN;
2239 if ((nfds = poll(pfd, 1, INFTIM)) == -1)
2240 if (errno != EINTR)
2241 error("poll error");
2242
2243 /*
2244 * Handle temporary errors, but bail if they persist.
2245 */
2246 if (nfds == 0 || !(pfd[0].revents & POLLIN)) {
2247 if (pfail > POLL_FAILURES)
2248 error("poll failed > %d times", POLL_FAILURES);
2249 sleep(pfail * POLL_FAILURE_WAIT);
2250 pfail++;
2251 continue;
2252 }
2253
2254 dispatch_imsg(fd);
2255 }
2256 }
2257
2258 void
get_ifname(char * ifname,char * arg)2259 get_ifname(char *ifname, char *arg)
2260 {
2261 struct ifgroupreq ifgr;
2262 struct ifg_req *ifg;
2263 int s, len;
2264
2265 if (!strcmp(arg, "egress")) {
2266 s = socket(AF_INET, SOCK_DGRAM, 0);
2267 if (s == -1)
2268 error("socket error");
2269 bzero(&ifgr, sizeof(ifgr));
2270 strlcpy(ifgr.ifgr_name, "egress", sizeof(ifgr.ifgr_name));
2271 if (ioctl(s, SIOCGIFGMEMB, (caddr_t)&ifgr) == -1) {
2272 if (errno == ENOENT)
2273 error("no interface in group egress found");
2274 error("ioctl SIOCGIFGMEMB: %m");
2275 }
2276 len = ifgr.ifgr_len;
2277 if ((ifgr.ifgr_groups = calloc(1, len)) == NULL)
2278 error("get_ifname");
2279 if (ioctl(s, SIOCGIFGMEMB, (caddr_t)&ifgr) == -1)
2280 error("ioctl SIOCGIFGMEMB: %m");
2281
2282 arg = NULL;
2283 for (ifg = ifgr.ifgr_groups;
2284 ifg && len >= sizeof(struct ifg_req); ifg++) {
2285 len -= sizeof(struct ifg_req);
2286 if (arg)
2287 error("too many interfaces in group egress");
2288 arg = ifg->ifgrq_member;
2289 }
2290
2291 if (strlcpy(ifi->name, arg, IFNAMSIZ) >= IFNAMSIZ)
2292 error("Interface name too long: %m");
2293
2294 free(ifgr.ifgr_groups);
2295 close(s);
2296 } else if (strlcpy(ifi->name, arg, IFNAMSIZ) >= IFNAMSIZ)
2297 error("Interface name too long");
2298 }
2299
2300 static
2301 void
sig_handle(int signo)2302 sig_handle(int signo)
2303 {
2304 if (monitor_pid > 0)
2305 kill(monitor_pid, signo);
2306 fprintf(stderr, "killed by signal\n");
2307 exit(1);
2308 }
2309
2310 static
2311 int
killclient(int fd)2312 killclient(int fd)
2313 {
2314 int noclient = 1;
2315
2316 /*
2317 * Kill previously running dhclient
2318 */
2319 if (flock(fd, LOCK_EX|LOCK_NB) < 0) {
2320 char buf[256];
2321 ssize_t n;
2322 pid_t pid;
2323
2324 lseek(fd, 0L, SEEK_SET);
2325 n = read(fd, buf, sizeof(buf));
2326 if (n > 0) {
2327 buf[n-1] = 0;
2328 pid = strtol(buf, NULL, 10);
2329 if ((int)pid > 0) {
2330 noclient = 0;
2331 kill(pid, SIGINT);
2332 }
2333 }
2334 if (flock(fd, LOCK_EX|LOCK_NB) < 0)
2335 usleep(20000);
2336 while (flock(fd, LOCK_EX|LOCK_NB) < 0)
2337 sleep(1);
2338 }
2339 return noclient;
2340 }
2341