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 int len = IFNAMSIZ + sizeof(struct sockaddr_storage);
84
85 if (getifaddrs(&ifap) != 0)
86 error("getifaddrs failed");
87
88 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
89 if ((ifa->ifa_flags & IFF_LOOPBACK) ||
90 (ifa->ifa_flags & IFF_POINTOPOINT) ||
91 (!(ifa->ifa_flags & IFF_UP)))
92 continue;
93
94 if (strcmp(iface->name, ifa->ifa_name))
95 continue;
96
97 /*
98 * If we have the capability, extract link information
99 * and record it in a linked list.
100 */
101 if (ifa->ifa_addr->sa_family == AF_LINK) {
102 struct sockaddr_dl *foo;
103
104 /*
105 * The implementation of getifaddrs should guarantee
106 * this alignment
107 */
108 assert_aligned(ifa->ifa_addr,
109 _Alignof(struct sockaddr_dl));
110 #ifdef __clang__
111 #pragma clang diagnostic push
112 #pragma clang diagnostic ignored "-Wcast-align"
113 #endif
114 foo = (struct sockaddr_dl *)ifa->ifa_addr;
115 #ifdef __clang__
116 #pragma clang diagnostic pop
117 #endif
118
119 iface->index = foo->sdl_index;
120 iface->hw_address.hlen = foo->sdl_alen;
121 iface->hw_address.htype = HTYPE_ETHER; /* XXX */
122 memcpy(iface->hw_address.haddr,
123 LLADDR(foo), foo->sdl_alen);
124 }
125 if (!iface->ifp) {
126 if ((tif = calloc(1, len)) == NULL)
127 error("no space to remember ifp");
128 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ);
129 iface->ifp = tif;
130 }
131
132 }
133
134 if (!iface->ifp)
135 error("%s: not found", iface->name);
136
137 /* Register the interface... */
138 if_register_receive(iface);
139 if_register_send(iface);
140 add_protocol(iface->name, iface->rfdesc, got_one, iface);
141 freeifaddrs(ifap);
142 }
143
144 void
reinitialize_interfaces(void)145 reinitialize_interfaces(void)
146 {
147 interfaces_invalidated = 1;
148 }
149
150 /*
151 * Wait for packets to come in using poll(). When a packet comes in,
152 * call receive_packet to receive the packet and possibly strip hardware
153 * addressing information from it, and then call through the
154 * bootp_packet_handler hook to try to do something with it.
155 */
156 void
dispatch(void)157 dispatch(void)
158 {
159 int count, live_interfaces, i, to_msec, nfds = 0;
160 struct protocol *l;
161 struct pollfd *fds;
162 struct timespec howlong;
163
164 clock_gettime(CLOCK_MONOTONIC, &time_now);
165
166 for (l = protocols; l; l = l->next)
167 nfds++;
168
169 fds = malloc(nfds * sizeof(struct pollfd));
170 if (fds == NULL)
171 error("Can't allocate poll structures.");
172
173 do {
174 /*
175 * Call any expired timeouts, and then if there's still
176 * a timeout registered, time out the select call then.
177 */
178 another:
179 if (timeouts) {
180 struct timeout *t;
181
182 if (timespeccmp(&timeouts->when, &time_now, <=)) {
183 t = timeouts;
184 timeouts = timeouts->next;
185 (*(t->func))(t->what);
186 t->next = free_timeouts;
187 free_timeouts = t;
188 goto another;
189 }
190
191 /*
192 * Figure timeout in milliseconds, and check for
193 * potential overflow, so we can cram into an
194 * int for poll, while not polling with a
195 * negative timeout and blocking indefinitely.
196 */
197 timespecsub(&timeouts->when, &time_now, &howlong);
198 if (timespeccmp(&howlong, ×pec_intmax_ms, >))
199 howlong = timespec_intmax_ms;
200 to_msec = howlong.tv_sec * 1000 + howlong.tv_nsec / 1000000;
201 } else
202 to_msec = -1;
203
204 /* Set up the descriptors to be polled. */
205 live_interfaces = 0;
206 for (i = 0, l = protocols; l; l = l->next) {
207 struct interface_info *ip = l->local;
208
209 if (ip == NULL || ip->dead)
210 continue;
211 fds[i].fd = l->fd;
212 fds[i].events = POLLIN;
213 fds[i].revents = 0;
214 i++;
215 if (l->handler == got_one)
216 live_interfaces++;
217 }
218 if (live_interfaces == 0)
219 error("No live interfaces to poll on - exiting.");
220
221 /* Wait for a packet or a timeout... XXX */
222 count = poll(fds, nfds, to_msec);
223
224 /* Not likely to be transitory... */
225 if (count == -1) {
226 if (errno == EAGAIN || errno == EINTR) {
227 clock_gettime(CLOCK_MONOTONIC, &time_now);
228 cur_time = time(NULL);
229 continue;
230 } else
231 error("poll: %m");
232 }
233
234 /* Get the current time... */
235 clock_gettime(CLOCK_MONOTONIC, &time_now);
236 cur_time = time(NULL);
237
238 i = 0;
239 for (l = protocols; l; l = l->next) {
240 struct interface_info *ip;
241 ip = l->local;
242 if ((fds[i].revents & (POLLIN | POLLHUP))) {
243 fds[i].revents = 0;
244 if (ip && (l->handler != got_one ||
245 !ip->dead))
246 (*(l->handler))(l);
247 if (interfaces_invalidated)
248 break;
249 }
250 i++;
251 }
252 interfaces_invalidated = 0;
253 } while (1);
254 }
255
256
257 void
got_one(struct protocol * l)258 got_one(struct protocol *l)
259 {
260 struct sockaddr_in from;
261 struct hardware hfrom;
262 struct iaddr ifrom;
263 ssize_t result;
264 union {
265 /*
266 * Packet input buffer. Must be as large as largest
267 * possible MTU.
268 */
269 unsigned char packbuf[4095];
270 struct dhcp_packet packet;
271 } u;
272 struct interface_info *ip = l->local;
273
274 if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from,
275 &hfrom)) == -1) {
276 warning("receive_packet failed on %s: %s", ip->name,
277 strerror(errno));
278 ip->errors++;
279 if ((!interface_status(ip)) ||
280 (ip->noifmedia && ip->errors > 20)) {
281 /* our interface has gone away. */
282 warning("Interface %s no longer appears valid.",
283 ip->name);
284 ip->dead = 1;
285 interfaces_invalidated = 1;
286 close(l->fd);
287 remove_protocol(l);
288 free(ip);
289 }
290 return;
291 }
292 if (result == 0)
293 return;
294
295 if (bootp_packet_handler) {
296 ifrom.len = 4;
297 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len);
298
299 (*bootp_packet_handler)(ip, &u.packet, result,
300 from.sin_port, ifrom, &hfrom);
301 }
302 }
303
304 int
interface_status(struct interface_info * ifinfo)305 interface_status(struct interface_info *ifinfo)
306 {
307 char *ifname = ifinfo->name;
308 int ifsock = ifinfo->rfdesc;
309 struct ifreq ifr;
310 struct ifmediareq ifmr;
311
312 /* get interface flags */
313 memset(&ifr, 0, sizeof(ifr));
314 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
315 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) {
316 cap_syslog(capsyslog, LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m",
317 ifname);
318 goto inactive;
319 }
320
321 /*
322 * if one of UP and RUNNING flags is dropped,
323 * the interface is not active.
324 */
325 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
326 goto inactive;
327
328 /* Next, check carrier on the interface, if possible */
329 if (ifinfo->noifmedia)
330 goto active;
331 memset(&ifmr, 0, sizeof(ifmr));
332 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
333 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) {
334 if (errno != EINVAL) {
335 cap_syslog(capsyslog, LOG_DEBUG,
336 "ioctl(SIOCGIFMEDIA) on %s: %m", ifname);
337 ifinfo->noifmedia = 1;
338 goto active;
339 }
340 /*
341 * EINVAL (or ENOTTY) simply means that the interface
342 * does not support the SIOCGIFMEDIA ioctl. We regard it alive.
343 */
344 ifinfo->noifmedia = 1;
345 goto active;
346 }
347 if (ifmr.ifm_status & IFM_AVALID) {
348 switch (ifmr.ifm_active & IFM_NMASK) {
349 case IFM_ETHER:
350 case IFM_IEEE80211:
351 if (ifmr.ifm_status & IFM_ACTIVE)
352 goto active;
353 else
354 goto inactive;
355 break;
356 default:
357 goto inactive;
358 }
359 }
360 inactive:
361 return (0);
362 active:
363 return (1);
364 }
365
366 void
add_timeout(time_t when_s,void (* where)(void *),void * what)367 add_timeout(time_t when_s, void (*where)(void *), void *what)
368 {
369 struct timespec when;
370
371 cur_time = time(NULL);
372 clock_gettime(CLOCK_MONOTONIC, &when);
373 when.tv_sec += when_s - cur_time;
374 add_timeout_timespec(when, where, what);
375 }
376
377 void
add_timeout_timespec(struct timespec when,void (* where)(void *),void * what)378 add_timeout_timespec(struct timespec when, void (*where)(void *), void *what)
379 {
380 struct timeout *t, *q;
381
382 /* See if this timeout supersedes an existing timeout. */
383 t = NULL;
384 for (q = timeouts; q; q = q->next) {
385 if (q->func == where && q->what == what) {
386 if (t)
387 t->next = q->next;
388 else
389 timeouts = q->next;
390 break;
391 }
392 t = q;
393 }
394
395 /* If we didn't supersede a timeout, allocate a timeout
396 structure now. */
397 if (!q) {
398 if (free_timeouts) {
399 q = free_timeouts;
400 free_timeouts = q->next;
401 q->func = where;
402 q->what = what;
403 } else {
404 q = malloc(sizeof(struct timeout));
405 if (!q)
406 error("Can't allocate timeout structure!");
407 q->func = where;
408 q->what = what;
409 }
410 }
411
412 q->when = when;
413
414 /* Now sort this timeout into the timeout list. */
415
416 /* Beginning of list? */
417 if (!timeouts || timespeccmp(&timeouts->when, &q->when, >)) {
418 q->next = timeouts;
419 timeouts = q;
420 return;
421 }
422
423 /* Middle of list? */
424 for (t = timeouts; t->next; t = t->next) {
425 if (timespeccmp(&t->next->when, &q->when, >)) {
426 q->next = t->next;
427 t->next = q;
428 return;
429 }
430 }
431
432 /* End of list. */
433 t->next = q;
434 q->next = NULL;
435 }
436
437 void
cancel_timeout(void (* where)(void *),void * what)438 cancel_timeout(void (*where)(void *), void *what)
439 {
440 struct timeout *t, *q;
441
442 /* Look for this timeout on the list, and unlink it if we find it. */
443 t = NULL;
444 for (q = timeouts; q; q = q->next) {
445 if (q->func == where && q->what == what) {
446 if (t)
447 t->next = q->next;
448 else
449 timeouts = q->next;
450 break;
451 }
452 t = q;
453 }
454
455 /* If we found the timeout, put it on the free list. */
456 if (q) {
457 q->next = free_timeouts;
458 free_timeouts = q;
459 }
460 }
461
462 /* Add a protocol to the list of protocols... */
463 void
add_protocol(const char * name,int fd,void (* handler)(struct protocol *),void * local)464 add_protocol(const char *name, int fd, void (*handler)(struct protocol *),
465 void *local)
466 {
467 struct protocol *p;
468
469 p = malloc(sizeof(*p));
470 if (!p)
471 error("can't allocate protocol struct for %s", name);
472
473 p->fd = fd;
474 p->handler = handler;
475 p->local = local;
476 p->next = protocols;
477 protocols = p;
478 }
479
480 void
remove_protocol(struct protocol * proto)481 remove_protocol(struct protocol *proto)
482 {
483 struct protocol *p, *prev;
484
485 for (p = protocols, prev = NULL; p != NULL; prev = p, p = p->next) {
486 if (p == proto) {
487 if (prev == NULL)
488 protocols = p->next;
489 else
490 prev->next = p->next;
491 free(p);
492 break;
493 }
494 }
495 }
496
497 int
interface_link_status(char * ifname)498 interface_link_status(char *ifname)
499 {
500 struct ifmediareq ifmr;
501 int sock;
502
503 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
504 error("Can't create socket");
505
506 memset(&ifmr, 0, sizeof(ifmr));
507 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
508 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) {
509 /* EINVAL -> link state unknown. treat as active */
510 if (errno != EINVAL)
511 cap_syslog(capsyslog, LOG_DEBUG,
512 "ioctl(SIOCGIFMEDIA) on %s: %m", ifname);
513 close(sock);
514 return (1);
515 }
516 close(sock);
517
518 if (ifmr.ifm_status & IFM_AVALID) {
519 switch (ifmr.ifm_active & IFM_NMASK) {
520 case IFM_ETHER:
521 case IFM_IEEE80211:
522 if (ifmr.ifm_status & IFM_ACTIVE)
523 return (1);
524 else
525 return (0);
526 }
527 }
528 return (1);
529 }
530
531 void
interface_set_mtu_unpriv(int privfd,u_int16_t mtu)532 interface_set_mtu_unpriv(int privfd, u_int16_t mtu)
533 {
534 struct imsg_hdr hdr;
535 struct buf *buf;
536 int errs = 0;
537
538 hdr.code = IMSG_SET_INTERFACE_MTU;
539 hdr.len = sizeof(hdr) +
540 sizeof(u_int16_t);
541
542 if ((buf = buf_open(hdr.len)) == NULL)
543 error("buf_open: %m");
544
545 errs += buf_add(buf, &hdr, sizeof(hdr));
546 errs += buf_add(buf, &mtu, sizeof(mtu));
547 if (errs)
548 error("buf_add: %m");
549
550 if (buf_close(privfd, buf) == -1)
551 error("buf_close: %m");
552 }
553
554 void
interface_set_mtu_priv(char * ifname,u_int16_t mtu)555 interface_set_mtu_priv(char *ifname, u_int16_t mtu)
556 {
557 struct ifreq ifr;
558 int sock;
559 u_int16_t old_mtu;
560
561 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
562 error("Can't create socket");
563
564 memset(&ifr, 0, sizeof(ifr));
565 old_mtu = 0;
566
567 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
568
569 if (ioctl(sock, SIOCGIFMTU, (caddr_t)&ifr) == -1)
570 warning("SIOCGIFMTU failed (%s): %s", ifname,
571 strerror(errno));
572 else
573 old_mtu = ifr.ifr_mtu;
574
575 if (mtu != old_mtu) {
576 ifr.ifr_mtu = mtu;
577
578 if (ioctl(sock, SIOCSIFMTU, &ifr) == -1)
579 warning("SIOCSIFMTU failed (%d): %s", mtu,
580 strerror(errno));
581 }
582
583 close(sock);
584 }
585