GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: usr.sbin/dhcpd/dispatch.c Lines: 0 272 0.0 %
Date: 2017-11-13 Branches: 0 193 0.0 %

Line Branch Exec Source
1
/*	$OpenBSD: dispatch.c,v 1.43 2017/04/12 19:17:30 krw Exp $ */
2
3
/*
4
 * Copyright (c) 1995, 1996, 1997, 1998, 1999
5
 * The Internet Software Consortium.   All rights reserved.
6
 *
7
 * Redistribution and use in source and binary forms, with or without
8
 * modification, are permitted provided that the following conditions
9
 * are met:
10
 *
11
 * 1. Redistributions of source code must retain the above copyright
12
 *    notice, this list of conditions and the following disclaimer.
13
 * 2. Redistributions in binary form must reproduce the above copyright
14
 *    notice, this list of conditions and the following disclaimer in the
15
 *    documentation and/or other materials provided with the distribution.
16
 * 3. Neither the name of The Internet Software Consortium nor the names
17
 *    of its contributors may be used to endorse or promote products derived
18
 *    from this software without specific prior written permission.
19
 *
20
 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
21
 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
22
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
24
 * DISCLAIMED.  IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
25
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
28
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
29
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32
 * SUCH DAMAGE.
33
 *
34
 * This software has been written for the Internet Software Consortium
35
 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
36
 * Enterprises.  To learn more about the Internet Software Consortium,
37
 * see ``http://www.vix.com/isc''.  To learn more about Vixie
38
 * Enterprises, see ``http://www.vix.com''.
39
 */
40
41
#include <sys/types.h>
42
#include <sys/ioctl.h>
43
#include <sys/socket.h>
44
45
#include <arpa/inet.h>
46
47
#include <net/if.h>
48
#include <net/if_dl.h>
49
#include <net/if_media.h>
50
51
#include <netinet/in.h>
52
53
#include <errno.h>
54
#include <ifaddrs.h>
55
#include <limits.h>
56
#include <poll.h>
57
#include <stdio.h>
58
#include <stdlib.h>
59
#include <string.h>
60
#include <syslog.h>
61
#include <time.h>
62
#include <unistd.h>
63
64
#include "dhcp.h"
65
#include "tree.h"
66
#include "dhcpd.h"
67
#include "log.h"
68
#include "sync.h"
69
70
extern int syncfd;
71
72
struct interface_info *interfaces;
73
struct protocol *protocols;
74
struct dhcpd_timeout *timeouts;
75
static struct dhcpd_timeout *free_timeouts;
76
static int interfaces_invalidated;
77
78
static int interface_status(struct interface_info *ifinfo);
79
int get_rdomain(char *);
80
81
/* Use getifaddrs() to get a list of all the attached interfaces.
82
   For each interface that's of type INET and not the loopback interface,
83
   register that interface with the network I/O software, figure out what
84
   subnet it's on, and add it to the list of interfaces. */
85
86
void
87
discover_interfaces(int *rdomain)
88
{
89
	struct interface_info *tmp;
90
	struct interface_info *last, *next;
91
	struct subnet *subnet;
92
	struct shared_network *share;
93
	struct sockaddr_in foo;
94
	int ir = 0, ird;
95
	struct ifreq *tif;
96
	struct ifaddrs *ifap, *ifa;
97
98
	if (getifaddrs(&ifap) != 0)
99
		fatalx("getifaddrs failed");
100
101
	/*
102
	 * If we already have a list of interfaces, the interfaces were
103
	 * requested.
104
	 */
105
	if (interfaces != NULL)
106
		ir = 1;
107
	else
108
		/* must specify an interface when rdomains are used */
109
		*rdomain = 0;
110
111
	/* Cycle through the list of interfaces looking for IP addresses. */
112
	for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
113
		/*
114
		 * See if this is the sort of interface we want to
115
		 * deal with.  Skip loopback, point-to-point and down
116
		 * interfaces, except don't skip down interfaces if we're
117
		 * trying to get a list of configurable interfaces.
118
		 */
119
		if ((ifa->ifa_flags & IFF_LOOPBACK) ||
120
		    (ifa->ifa_flags & IFF_POINTOPOINT) ||
121
		    (!(ifa->ifa_flags & IFF_UP)) ||
122
		    (!(ifa->ifa_flags & IFF_BROADCAST)))
123
			continue;
124
125
		/* See if we've seen an interface that matches this one. */
126
		for (tmp = interfaces; tmp; tmp = tmp->next)
127
			if (!strcmp(tmp->name, ifa->ifa_name))
128
				break;
129
130
		/* If we are looking for specific interfaces, ignore others. */
131
		if (tmp == NULL && ir)
132
			continue;
133
134
		ird = get_rdomain(ifa->ifa_name);
135
		if (*rdomain == -1)
136
			*rdomain = ird;
137
		else if (*rdomain != ird && ir)
138
			fatalx("Interface %s is not in rdomain %d",
139
			    tmp->name, *rdomain);
140
		else if (*rdomain != ird && !ir)
141
			continue;
142
143
		/* If there isn't already an interface by this name,
144
		   allocate one. */
145
		if (tmp == NULL) {
146
			tmp = calloc(1, sizeof *tmp);
147
			if (!tmp)
148
				fatalx("Insufficient memory to %s %s",
149
				    "record interface", ifa->ifa_name);
150
			strlcpy(tmp->name, ifa->ifa_name, sizeof(tmp->name));
151
			tmp->next = interfaces;
152
			tmp->noifmedia = tmp->dead = tmp->errors = 0;
153
			interfaces = tmp;
154
		}
155
156
		/* If we have the capability, extract link information
157
		   and record it in a linked list. */
158
		if (ifa->ifa_addr->sa_family == AF_LINK) {
159
			struct sockaddr_dl *sdl =
160
			    ((struct sockaddr_dl *)(ifa->ifa_addr));
161
			tmp->index = sdl->sdl_index;
162
			tmp->hw_address.hlen = sdl->sdl_alen;
163
			tmp->hw_address.htype = HTYPE_ETHER; /* XXX */
164
			memcpy(tmp->hw_address.haddr,
165
			    LLADDR(sdl), sdl->sdl_alen);
166
		} else if (ifa->ifa_addr->sa_family == AF_INET) {
167
			struct iaddr addr;
168
169
			/* Get a pointer to the address... */
170
			memcpy(&foo, ifa->ifa_addr, sizeof(foo));
171
172
			/* We don't want the loopback interface. */
173
			if (foo.sin_addr.s_addr == htonl (INADDR_LOOPBACK))
174
				continue;
175
176
			/* If this is the first real IP address we've
177
			   found, keep a pointer to ifreq structure in
178
			   which we found it. */
179
			if (!tmp->ifp) {
180
				int len = (IFNAMSIZ + ifa->ifa_addr->sa_len);
181
				tif = malloc(len);
182
				if (!tif)
183
					fatalx("no space to remember ifp.");
184
				strlcpy(tif->ifr_name, ifa->ifa_name,
185
				    IFNAMSIZ);
186
				memcpy(&tif->ifr_addr, ifa->ifa_addr,
187
				    ifa->ifa_addr->sa_len);
188
				tmp->ifp = tif;
189
				tmp->primary_address = foo.sin_addr;
190
			}
191
192
			/* Grab the address... */
193
			addr.len = 4;
194
			memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len);
195
196
			/* If there's a registered subnet for this address,
197
			   connect it together... */
198
			if ((subnet = find_subnet(addr))) {
199
				/* If this interface has multiple aliases
200
				   on the same subnet, ignore all but the
201
				   first we encounter. */
202
				if (!subnet->interface) {
203
					subnet->interface = tmp;
204
					subnet->interface_address = addr;
205
				} else if (subnet->interface != tmp) {
206
					log_warnx("Multiple %s %s: %s %s",
207
					    "interfaces match the",
208
					    "same subnet",
209
					    subnet->interface->name,
210
					    tmp->name);
211
				}
212
				share = subnet->shared_network;
213
				if (tmp->shared_network &&
214
				    tmp->shared_network != share) {
215
					log_warnx("Interface %s matches %s",
216
					    tmp->name,
217
					    "multiple shared networks");
218
				} else {
219
					tmp->shared_network = share;
220
				}
221
222
				if (!share->interface) {
223
					share->interface = tmp;
224
				} else if (share->interface != tmp) {
225
					log_warnx("Multiple %s %s: %s %s",
226
					    "interfaces match the",
227
					    "same shared network",
228
					    share->interface->name,
229
					    tmp->name);
230
				}
231
			}
232
		}
233
	}
234
235
	/* Discard interfaces we can't listen on. */
236
	last = NULL;
237
	for (tmp = interfaces; tmp; tmp = next) {
238
		next = tmp->next;
239
240
		if (!tmp->ifp) {
241
			log_warnx("Can't listen on %s - it has no IP address.",
242
			    tmp->name);
243
			/* Remove tmp from the list of interfaces. */
244
			if (!last)
245
				interfaces = interfaces->next;
246
			else
247
				last->next = tmp->next;
248
			continue;
249
		}
250
251
		memcpy(&foo, &tmp->ifp->ifr_addr, sizeof tmp->ifp->ifr_addr);
252
253
		if (!tmp->shared_network) {
254
			log_warnx("Can't listen on %s - dhcpd.conf has no "
255
			    "subnet declaration for %s.", tmp->name,
256
			    inet_ntoa(foo.sin_addr));
257
			/* Remove tmp from the list of interfaces. */
258
			if (!last)
259
				interfaces = interfaces->next;
260
			else
261
				last->next = tmp->next;
262
			continue;
263
		}
264
265
		last = tmp;
266
267
		/* Find subnets that don't have valid interface addresses. */
268
		for (subnet = (tmp->shared_network ?
269
		    tmp->shared_network->subnets : NULL); subnet;
270
		    subnet = subnet->next_sibling) {
271
			if (!subnet->interface_address.len) {
272
				/*
273
				 * Set the interface address for this subnet
274
				 * to the first address we found.
275
				 */
276
				subnet->interface_address.len = 4;
277
				memcpy(subnet->interface_address.iabuf,
278
				    &foo.sin_addr.s_addr, 4);
279
			}
280
		}
281
282
		/* Register the interface... */
283
		if_register_receive(tmp);
284
		if_register_send(tmp);
285
		log_info("Listening on %s (%s).", tmp->name,
286
		    inet_ntoa(foo.sin_addr));
287
	}
288
289
	if (interfaces == NULL)
290
		fatalx("No interfaces to listen on.");
291
292
	/* Now register all the remaining interfaces as protocols. */
293
	for (tmp = interfaces; tmp; tmp = tmp->next)
294
		add_protocol(tmp->name, tmp->rfdesc, got_one, tmp);
295
296
	freeifaddrs(ifap);
297
}
298
299
/*
300
 * Wait for packets to come in using poll().  When a packet comes in,
301
 * call receive_packet to receive the packet and possibly strip hardware
302
 * addressing information from it, and then process it in do_packet.
303
 */
304
void
305
dispatch(void)
306
{
307
	int nfds, i, to_msec;
308
	struct protocol *l;
309
	static struct pollfd *fds;
310
	static int nfds_max;
311
	time_t howlong;
312
313
	for (nfds = 0, l = protocols; l; l = l->next)
314
		nfds++;
315
	if (syncfd != -1)
316
		nfds++;
317
	if (nfds > nfds_max) {
318
		fds = reallocarray(fds, nfds, sizeof(struct pollfd));
319
		if (fds == NULL)
320
			fatalx("Can't allocate poll structures.");
321
		nfds_max = nfds;
322
	}
323
324
	for (;;) {
325
		/*
326
		 * Call any expired timeouts, and then if there's
327
		 * still a timeout registered, time out the poll
328
		 * call then.
329
		 */
330
		time(&cur_time);
331
another:
332
		if (timeouts) {
333
			if (timeouts->when <= cur_time) {
334
				struct dhcpd_timeout *t = timeouts;
335
				timeouts = timeouts->next;
336
				(*(t->func))(t->what);
337
				t->next = free_timeouts;
338
				free_timeouts = t;
339
				goto another;
340
			}
341
342
			/*
343
			 * Figure timeout in milliseconds, and check for
344
			 * potential overflow, so we can cram into an int
345
			 * for poll, while not polling with a negative
346
			 * timeout and blocking indefinitely.
347
			 */
348
			howlong = timeouts->when - cur_time;
349
			if (howlong > INT_MAX / 1000)
350
				howlong = INT_MAX / 1000;
351
			to_msec = howlong * 1000;
352
		} else
353
			to_msec = -1;
354
355
		/* Set up the descriptors to be polled. */
356
		for (i = 0, l = protocols; l; l = l->next) {
357
			struct interface_info *ip = l->local;
358
359
			if (ip && (l->handler != got_one || !ip->dead)) {
360
				fds[i].fd = l->fd;
361
				fds[i].events = POLLIN;
362
				++i;
363
			}
364
		}
365
366
		if (i == 0)
367
			fatalx("No live interfaces to poll on - exiting.");
368
369
		if (syncfd != -1) {
370
			/* add syncer */
371
			fds[i].fd = syncfd;
372
			fds[i].events = POLLIN;
373
		}
374
375
		/* Wait for a packet or a timeout... */
376
		switch (poll(fds, nfds, to_msec)) {
377
		case -1:
378
			if (errno != EAGAIN && errno != EINTR)
379
				fatal("poll");
380
			/* FALLTHROUGH */
381
		case 0:
382
			continue;	/* no packets */
383
		}
384
		time(&cur_time);
385
386
		for (i = 0, l = protocols; l; l = l->next) {
387
			struct interface_info *ip = l->local;
388
389
			if ((fds[i].revents & (POLLIN | POLLHUP))) {
390
				if (ip && (l->handler != got_one ||
391
				    !ip->dead))
392
					(*(l->handler))(l);
393
				if (interfaces_invalidated)
394
					break;
395
			}
396
			++i;
397
		}
398
		if ((syncfd != -1) && (fds[i].revents & (POLLIN | POLLHUP)))
399
			sync_recv();
400
		interfaces_invalidated = 0;
401
	}
402
}
403
404
405
void
406
got_one(struct protocol *l)
407
{
408
	struct sockaddr_in from;
409
	struct hardware hfrom;
410
	struct iaddr ifrom;
411
	ssize_t result;
412
	union {
413
		unsigned char packbuf[4095];
414
		struct dhcp_packet packet;
415
	} u;
416
	struct interface_info *ip = l->local;
417
418
	memset(&u, 0, sizeof(u));
419
420
	if ((result = receive_packet(ip, u.packbuf, sizeof u,
421
	    &from, &hfrom)) == -1) {
422
		log_warn("receive_packet failed on %s", ip->name);
423
		ip->errors++;
424
		if ((!interface_status(ip)) ||
425
		    (ip->noifmedia && ip->errors > 20)) {
426
			/* our interface has gone away. */
427
			log_warnx("Interface %s no longer appears valid.",
428
			    ip->name);
429
			ip->dead = 1;
430
			interfaces_invalidated = 1;
431
			close(l->fd);
432
			remove_protocol(l);
433
			free(ip);
434
		}
435
		return;
436
	}
437
	if (result == 0)
438
		return;
439
440
	ifrom.len = 4;
441
	memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len);
442
443
	do_packet(ip, &u.packet, result, from.sin_port, ifrom, &hfrom);
444
}
445
446
int
447
interface_status(struct interface_info *ifinfo)
448
{
449
	char * ifname = ifinfo->name;
450
	int ifsock = ifinfo->rfdesc;
451
	struct ifreq ifr;
452
	struct ifmediareq ifmr;
453
454
	/* get interface flags */
455
	memset(&ifr, 0, sizeof(ifr));
456
	strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
457
	if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) == -1) {
458
		log_warn("ioctl(SIOCGIFFLAGS) on %s", ifname);
459
		goto inactive;
460
	}
461
	/*
462
	 * if one of UP and RUNNING flags is dropped,
463
	 * the interface is not active.
464
	 */
465
	if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
466
		goto inactive;
467
468
	/* Next, check carrier on the interface, if possible */
469
	if (ifinfo->noifmedia)
470
		goto active;
471
	memset(&ifmr, 0, sizeof(ifmr));
472
	strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
473
	if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) {
474
		if (errno != EINVAL) {
475
			log_debug("ioctl(SIOCGIFMEDIA) on %s", ifname);
476
			ifinfo->noifmedia = 1;
477
			goto active;
478
		}
479
		/*
480
		 * EINVAL (or ENOTTY) simply means that the interface
481
		 * does not support the SIOCGIFMEDIA ioctl. We regard it alive.
482
		 */
483
		ifinfo->noifmedia = 1;
484
		goto active;
485
	}
486
	if (ifmr.ifm_status & IFM_AVALID) {
487
		switch (ifmr.ifm_active & IFM_NMASK) {
488
		case IFM_ETHER:
489
			if (ifmr.ifm_status & IFM_ACTIVE)
490
				goto active;
491
			else
492
				goto inactive;
493
			break;
494
		default:
495
			goto inactive;
496
		}
497
	}
498
 inactive:
499
	return (0);
500
 active:
501
	return (1);
502
}
503
504
int
505
locate_network(struct packet *packet)
506
{
507
	struct iaddr ia;
508
509
	/* If this came through a gateway, find the corresponding subnet... */
510
	if (packet->raw->giaddr.s_addr) {
511
		struct subnet *subnet;
512
513
		ia.len = 4;
514
		memcpy(ia.iabuf, &packet->raw->giaddr, 4);
515
		subnet = find_subnet(ia);
516
		if (subnet)
517
			packet->shared_network = subnet->shared_network;
518
		else
519
			packet->shared_network = NULL;
520
	} else {
521
		packet->shared_network = packet->interface->shared_network;
522
	}
523
	if (packet->shared_network)
524
		return 1;
525
	return 0;
526
}
527
528
void
529
add_timeout(time_t when, void (*where)(void *), void *what)
530
{
531
	struct dhcpd_timeout *t, *q;
532
533
	/* See if this timeout supersedes an existing timeout. */
534
	t = NULL;
535
	for (q = timeouts; q; q = q->next) {
536
		if (q->func == where && q->what == what) {
537
			if (t)
538
				t->next = q->next;
539
			else
540
				timeouts = q->next;
541
			break;
542
		}
543
		t = q;
544
	}
545
546
	/* If we didn't supersede a timeout, allocate a timeout
547
	   structure now. */
548
	if (!q) {
549
		if (free_timeouts) {
550
			q = free_timeouts;
551
			free_timeouts = q->next;
552
			q->func = where;
553
			q->what = what;
554
		} else {
555
			q = malloc(sizeof (struct dhcpd_timeout));
556
			if (!q)
557
				fatalx("Can't allocate timeout structure!");
558
			q->func = where;
559
			q->what = what;
560
		}
561
	}
562
563
	q->when = when;
564
565
	/* Now sort this timeout into the timeout list. */
566
567
	/* Beginning of list? */
568
	if (!timeouts || timeouts->when > q->when) {
569
		q->next = timeouts;
570
		timeouts = q;
571
		return;
572
	}
573
574
	/* Middle of list? */
575
	for (t = timeouts; t->next; t = t->next) {
576
		if (t->next->when > q->when) {
577
			q->next = t->next;
578
			t->next = q;
579
			return;
580
		}
581
	}
582
583
	/* End of list. */
584
	t->next = q;
585
	q->next = NULL;
586
}
587
588
void
589
cancel_timeout(void (*where)(void *), void *what)
590
{
591
	struct dhcpd_timeout *t, *q;
592
593
	/* Look for this timeout on the list, and unlink it if we find it. */
594
	t = NULL;
595
	for (q = timeouts; q; q = q->next) {
596
		if (q->func == where && q->what == what) {
597
			if (t)
598
				t->next = q->next;
599
			else
600
				timeouts = q->next;
601
			break;
602
		}
603
		t = q;
604
	}
605
606
	/* If we found the timeout, put it on the free list. */
607
	if (q) {
608
		q->next = free_timeouts;
609
		free_timeouts = q;
610
	}
611
}
612
613
/* Add a protocol to the list of protocols... */
614
void
615
add_protocol(char *name, int fd, void (*handler)(struct protocol *),
616
    void *local)
617
{
618
	struct protocol *p;
619
620
	p = malloc(sizeof *p);
621
	if (!p)
622
		fatalx("can't allocate protocol struct for %s", name);
623
	p->fd = fd;
624
	p->handler = handler;
625
	p->local = local;
626
	p->next = protocols;
627
	protocols = p;
628
}
629
630
void
631
remove_protocol(struct protocol *proto)
632
{
633
	struct protocol *p, *next, *prev = NULL;
634
635
	for (p = protocols; p; p = next) {
636
		next = p->next;
637
		if (p == proto) {
638
			if (prev)
639
				prev->next = p->next;
640
			else
641
				protocols = p->next;
642
			free(p);
643
		}
644
	}
645
}
646
647
int
648
get_rdomain(char *name)
649
{
650
	int rv = 0, s;
651
	struct  ifreq ifr;
652
653
	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
654
		fatal("get_rdomain socket");
655
656
	memset(&ifr, 0, sizeof(ifr));
657
	strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
658
	if (ioctl(s, SIOCGIFRDOMAIN, (caddr_t)&ifr) != -1)
659
		rv = ifr.ifr_rdomainid;
660
661
	close(s);
662
	return rv;
663
}