1 /* $OpenBSD: dispatch.c,v 1.31 2004/09/21 04:07:03 david Exp $ */
2
3 /*-
4 * SPDX-License-Identifier: BSD-3-Clause
5 *
6 * Copyright 2004 Henning Brauer <henning@openbsd.org>
7 * Copyright (c) 1995, 1996, 1997, 1998, 1999
8 * The Internet Software Consortium. All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 *
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of The Internet Software Consortium nor the names
20 * of its contributors may be used to endorse or promote products derived
21 * from this software without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
24 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
25 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
26 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
27 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
28 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
29 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
30 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
31 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
32 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
33 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
34 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * This software has been written for the Internet Software Consortium
38 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
39 * Enterprises. To learn more about the Internet Software Consortium,
40 * see ``http://www.vix.com/isc''. To learn more about Vixie
41 * Enterprises, see ``http://www.vix.com''.
42 */
43
44 #include <sys/cdefs.h>
45 #include "dhcpd.h"
46 #include "privsep.h"
47
48 #include <sys/ioctl.h>
49
50 #include <assert.h>
51 #include <net/if_media.h>
52 #include <ifaddrs.h>
53 #include <poll.h>
54
55 /* Assert that pointer p is aligned to at least align bytes */
56 #define assert_aligned(p, align) assert((((uintptr_t)p) & ((align) - 1)) == 0)
57
58 static struct protocol *protocols;
59 static const struct timespec timespec_intmax_ms = {
60 .tv_sec = INT_MAX / 1000,
61 .tv_nsec = (INT_MAX % 1000) * 1000000
62 };
63 static struct timeout *timeouts;
64 static struct timeout *free_timeouts;
65 static int interfaces_invalidated;
66 void (*bootp_packet_handler)(struct interface_info *,
67 struct dhcp_packet *, int, unsigned int,
68 struct iaddr, struct hardware *);
69
70 static int interface_status(struct interface_info *ifinfo);
71
72 /*
73 * Use getifaddrs() to get a list of all the attached interfaces. For
74 * each interface that's of type INET and not the loopback interface,
75 * register that interface with the network I/O software, figure out
76 * what subnet it's on, and add it to the list of interfaces.
77 */
78 void
discover_interfaces(struct interface_info * iface)79 discover_interfaces(struct interface_info *iface)
80 {
81 struct ifaddrs *ifap, *ifa;
82 struct ifreq *tif;
83
84 if (getifaddrs(&ifap) != 0)
85 error("getifaddrs failed");
86
87 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
88 if ((ifa->ifa_flags & IFF_LOOPBACK) ||
89 (ifa->ifa_flags & IFF_POINTOPOINT) ||
90 (!(ifa->ifa_flags & IFF_UP)))
91 continue;
92
93 if (strcmp(iface->name, ifa->ifa_name))
94 continue;
95
96 /*
97 * If we have the capability, extract link information
98 * and record it in a linked list.
99 */
100 if (ifa->ifa_addr->sa_family == AF_LINK) {
101 struct sockaddr_dl *foo;
102
103 /*
104 * The implementation of getifaddrs should guarantee
105 * this alignment
106 */
107 assert_aligned(ifa->ifa_addr,
108 _Alignof(struct sockaddr_dl));
109 #ifdef __clang__
110 #pragma clang diagnostic push
111 #pragma clang diagnostic ignored "-Wcast-align"
112 #endif
113 foo = (struct sockaddr_dl *)ifa->ifa_addr;
114 #ifdef __clang__
115 #pragma clang diagnostic pop
116 #endif
117
118 iface->index = foo->sdl_index;
119 iface->hw_address.hlen = foo->sdl_alen;
120 iface->hw_address.htype = HTYPE_ETHER; /* XXX */
121 memcpy(iface->hw_address.haddr,
122 LLADDR(foo), foo->sdl_alen);
123 }
124 if (!iface->ifp) {
125 if ((tif = calloc(1, sizeof(struct ifreq))) == NULL)
126 error("no space to remember ifp");
127 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ);
128 iface->ifp = tif;
129 }
130
131 }
132
133 if (!iface->ifp)
134 error("%s: not found", iface->name);
135
136 /* Register the interface... */
137 if_register_receive(iface);
138 if_register_send(iface);
139 add_protocol(iface->name, iface->rfdesc, got_one, iface);
140 freeifaddrs(ifap);
141 }
142
143 void
reinitialize_interfaces(void)144 reinitialize_interfaces(void)
145 {
146 interfaces_invalidated = 1;
147 }
148
149 /*
150 * Wait for packets to come in using poll(). When a packet comes in,
151 * call receive_packet to receive the packet and possibly strip hardware
152 * addressing information from it, and then call through the
153 * bootp_packet_handler hook to try to do something with it.
154 */
155 void
dispatch(void)156 dispatch(void)
157 {
158 int count, live_interfaces, i, to_msec, nfds = 0;
159 struct protocol *l;
160 struct pollfd *fds;
161 struct timespec howlong;
162 time_now.tv_sec = cur_time;
163 time_now.tv_nsec = 0;
164
165 for (l = protocols; l; l = l->next)
166 nfds++;
167
168 fds = malloc(nfds * sizeof(struct pollfd));
169 if (fds == NULL)
170 error("Can't allocate poll structures.");
171
172 do {
173 /*
174 * Call any expired timeouts, and then if there's still
175 * a timeout registered, time out the select call then.
176 */
177 another:
178 if (timeouts) {
179 struct timeout *t;
180
181 if (timespeccmp(&timeouts->when, &time_now, <=)) {
182 t = timeouts;
183 timeouts = timeouts->next;
184 (*(t->func))(t->what);
185 t->next = free_timeouts;
186 free_timeouts = t;
187 goto another;
188 }
189
190 /*
191 * Figure timeout in milliseconds, and check for
192 * potential overflow, so we can cram into an
193 * int for poll, while not polling with a
194 * negative timeout and blocking indefinitely.
195 */
196 timespecsub(&timeouts->when, &time_now, &howlong);
197 if (timespeccmp(&howlong, ×pec_intmax_ms, >))
198 howlong = timespec_intmax_ms;
199 to_msec = howlong.tv_sec * 1000 + howlong.tv_nsec / 1000000;
200 } else
201 to_msec = -1;
202
203 /* Set up the descriptors to be polled. */
204 live_interfaces = 0;
205 for (i = 0, l = protocols; l; l = l->next) {
206 struct interface_info *ip = l->local;
207
208 if (ip == NULL || ip->dead)
209 continue;
210 fds[i].fd = l->fd;
211 fds[i].events = POLLIN;
212 fds[i].revents = 0;
213 i++;
214 if (l->handler == got_one)
215 live_interfaces++;
216 }
217 if (live_interfaces == 0)
218 error("No live interfaces to poll on - exiting.");
219
220 /* Wait for a packet or a timeout... XXX */
221 count = poll(fds, nfds, to_msec);
222
223 /* Not likely to be transitory... */
224 if (count == -1) {
225 if (errno == EAGAIN || errno == EINTR) {
226 clock_gettime(CLOCK_MONOTONIC, &time_now);
227 cur_time = time_now.tv_sec;
228 continue;
229 } else
230 error("poll: %m");
231 }
232
233 /* Get the current time... */
234 clock_gettime(CLOCK_MONOTONIC, &time_now);
235 cur_time = time_now.tv_sec;
236
237 i = 0;
238 for (l = protocols; l; l = l->next) {
239 struct interface_info *ip;
240 ip = l->local;
241 if ((fds[i].revents & (POLLIN | POLLHUP))) {
242 fds[i].revents = 0;
243 if (ip && (l->handler != got_one ||
244 !ip->dead))
245 (*(l->handler))(l);
246 if (interfaces_invalidated)
247 break;
248 }
249 i++;
250 }
251 interfaces_invalidated = 0;
252 } while (1);
253 }
254
255
256 void
got_one(struct protocol * l)257 got_one(struct protocol *l)
258 {
259 struct sockaddr_in from;
260 struct hardware hfrom;
261 struct iaddr ifrom;
262 ssize_t result;
263 union {
264 /*
265 * Packet input buffer. Must be as large as largest
266 * possible MTU.
267 */
268 unsigned char packbuf[4095];
269 struct dhcp_packet packet;
270 } u;
271 struct interface_info *ip = l->local;
272
273 if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from,
274 &hfrom)) == -1) {
275 warning("receive_packet failed on %s: %s", ip->name,
276 strerror(errno));
277 ip->errors++;
278 if ((!interface_status(ip)) ||
279 (ip->noifmedia && ip->errors > 20)) {
280 /* our interface has gone away. */
281 warning("Interface %s no longer appears valid.",
282 ip->name);
283 ip->dead = 1;
284 interfaces_invalidated = 1;
285 close(l->fd);
286 remove_protocol(l);
287 free(ip);
288 }
289 return;
290 }
291 if (result == 0)
292 return;
293
294 if (bootp_packet_handler) {
295 ifrom.len = 4;
296 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len);
297
298 (*bootp_packet_handler)(ip, &u.packet, result,
299 from.sin_port, ifrom, &hfrom);
300 }
301 }
302
303 int
interface_status(struct interface_info * ifinfo)304 interface_status(struct interface_info *ifinfo)
305 {
306 char *ifname = ifinfo->name;
307 int ifsock = ifinfo->rfdesc;
308 struct ifreq ifr;
309 struct ifmediareq ifmr;
310
311 /* get interface flags */
312 memset(&ifr, 0, sizeof(ifr));
313 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
314 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) {
315 cap_syslog(capsyslog, LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m",
316 ifname);
317 goto inactive;
318 }
319
320 /*
321 * if one of UP and RUNNING flags is dropped,
322 * the interface is not active.
323 */
324 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
325 goto inactive;
326
327 /* Next, check carrier on the interface, if possible */
328 if (ifinfo->noifmedia)
329 goto active;
330 memset(&ifmr, 0, sizeof(ifmr));
331 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
332 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) {
333 if (errno != EINVAL) {
334 cap_syslog(capsyslog, LOG_DEBUG,
335 "ioctl(SIOCGIFMEDIA) on %s: %m", ifname);
336 ifinfo->noifmedia = 1;
337 goto active;
338 }
339 /*
340 * EINVAL (or ENOTTY) simply means that the interface
341 * does not support the SIOCGIFMEDIA ioctl. We regard it alive.
342 */
343 ifinfo->noifmedia = 1;
344 goto active;
345 }
346 if (ifmr.ifm_status & IFM_AVALID) {
347 switch (ifmr.ifm_active & IFM_NMASK) {
348 case IFM_ETHER:
349 case IFM_IEEE80211:
350 if (ifmr.ifm_status & IFM_ACTIVE)
351 goto active;
352 else
353 goto inactive;
354 break;
355 default:
356 goto inactive;
357 }
358 }
359 inactive:
360 return (0);
361 active:
362 return (1);
363 }
364
365 void
add_timeout(time_t when_s,void (* where)(void *),void * what)366 add_timeout(time_t when_s, void (*where)(void *), void *what)
367 {
368 struct timespec when = { .tv_sec = when_s, .tv_nsec = 0 };
369 add_timeout_timespec(when, where, what);
370 }
371
372 void
add_timeout_timespec(struct timespec when,void (* where)(void *),void * what)373 add_timeout_timespec(struct timespec when, void (*where)(void *), void *what)
374 {
375 struct timeout *t, *q;
376
377 /* See if this timeout supersedes an existing timeout. */
378 t = NULL;
379 for (q = timeouts; q; q = q->next) {
380 if (q->func == where && q->what == what) {
381 if (t)
382 t->next = q->next;
383 else
384 timeouts = q->next;
385 break;
386 }
387 t = q;
388 }
389
390 /* If we didn't supersede a timeout, allocate a timeout
391 structure now. */
392 if (!q) {
393 if (free_timeouts) {
394 q = free_timeouts;
395 free_timeouts = q->next;
396 q->func = where;
397 q->what = what;
398 } else {
399 q = malloc(sizeof(struct timeout));
400 if (!q)
401 error("Can't allocate timeout structure!");
402 q->func = where;
403 q->what = what;
404 }
405 }
406
407 q->when = when;
408
409 /* Now sort this timeout into the timeout list. */
410
411 /* Beginning of list? */
412 if (!timeouts || timespeccmp(&timeouts->when, &q->when, >)) {
413 q->next = timeouts;
414 timeouts = q;
415 return;
416 }
417
418 /* Middle of list? */
419 for (t = timeouts; t->next; t = t->next) {
420 if (timespeccmp(&t->next->when, &q->when, >)) {
421 q->next = t->next;
422 t->next = q;
423 return;
424 }
425 }
426
427 /* End of list. */
428 t->next = q;
429 q->next = NULL;
430 }
431
432 void
cancel_timeout(void (* where)(void *),void * what)433 cancel_timeout(void (*where)(void *), void *what)
434 {
435 struct timeout *t, *q;
436
437 /* Look for this timeout on the list, and unlink it if we find it. */
438 t = NULL;
439 for (q = timeouts; q; q = q->next) {
440 if (q->func == where && q->what == what) {
441 if (t)
442 t->next = q->next;
443 else
444 timeouts = q->next;
445 break;
446 }
447 t = q;
448 }
449
450 /* If we found the timeout, put it on the free list. */
451 if (q) {
452 q->next = free_timeouts;
453 free_timeouts = q;
454 }
455 }
456
457 /* Add a protocol to the list of protocols... */
458 void
add_protocol(const char * name,int fd,void (* handler)(struct protocol *),void * local)459 add_protocol(const char *name, int fd, void (*handler)(struct protocol *),
460 void *local)
461 {
462 struct protocol *p;
463
464 p = malloc(sizeof(*p));
465 if (!p)
466 error("can't allocate protocol struct for %s", name);
467
468 p->fd = fd;
469 p->handler = handler;
470 p->local = local;
471 p->next = protocols;
472 protocols = p;
473 }
474
475 void
remove_protocol(struct protocol * proto)476 remove_protocol(struct protocol *proto)
477 {
478 struct protocol *p, *prev;
479
480 for (p = protocols, prev = NULL; p != NULL; prev = p, p = p->next) {
481 if (p == proto) {
482 if (prev == NULL)
483 protocols = p->next;
484 else
485 prev->next = p->next;
486 free(p);
487 break;
488 }
489 }
490 }
491
492 int
interface_link_status(char * ifname)493 interface_link_status(char *ifname)
494 {
495 struct ifmediareq ifmr;
496 int sock;
497
498 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
499 error("Can't create socket");
500
501 memset(&ifmr, 0, sizeof(ifmr));
502 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
503 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) {
504 /* EINVAL -> link state unknown. treat as active */
505 if (errno != EINVAL)
506 cap_syslog(capsyslog, LOG_DEBUG,
507 "ioctl(SIOCGIFMEDIA) on %s: %m", ifname);
508 close(sock);
509 return (1);
510 }
511 close(sock);
512
513 if (ifmr.ifm_status & IFM_AVALID) {
514 switch (ifmr.ifm_active & IFM_NMASK) {
515 case IFM_ETHER:
516 case IFM_IEEE80211:
517 if (ifmr.ifm_status & IFM_ACTIVE)
518 return (1);
519 else
520 return (0);
521 }
522 }
523 return (1);
524 }
525
526 void
interface_set_mtu_unpriv(int privfd,u_int16_t mtu)527 interface_set_mtu_unpriv(int privfd, u_int16_t mtu)
528 {
529 struct imsg_hdr hdr;
530 struct buf *buf;
531 int errs = 0;
532
533 hdr.code = IMSG_SET_INTERFACE_MTU;
534 hdr.len = sizeof(hdr) +
535 sizeof(u_int16_t);
536
537 if ((buf = buf_open(hdr.len)) == NULL)
538 error("buf_open: %m");
539
540 errs += buf_add(buf, &hdr, sizeof(hdr));
541 errs += buf_add(buf, &mtu, sizeof(mtu));
542 if (errs)
543 error("buf_add: %m");
544
545 if (buf_close(privfd, buf) == -1)
546 error("buf_close: %m");
547 }
548
549 void
interface_set_mtu_priv(char * ifname,u_int16_t mtu)550 interface_set_mtu_priv(char *ifname, u_int16_t mtu)
551 {
552 struct ifreq ifr;
553 int sock;
554 u_int16_t old_mtu;
555
556 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
557 error("Can't create socket");
558
559 memset(&ifr, 0, sizeof(ifr));
560 old_mtu = 0;
561
562 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
563
564 if (ioctl(sock, SIOCGIFMTU, (caddr_t)&ifr) == -1)
565 warning("SIOCGIFMTU failed (%s): %s", ifname,
566 strerror(errno));
567 else
568 old_mtu = ifr.ifr_mtu;
569
570 if (mtu != old_mtu) {
571 ifr.ifr_mtu = mtu;
572
573 if (ioctl(sock, SIOCSIFMTU, &ifr) == -1)
574 warning("SIOCSIFMTU failed (%d): %s", mtu,
575 strerror(errno));
576 }
577
578 close(sock);
579 }
580