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 <[email protected]>
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 <[email protected]> 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 __FBSDID("$FreeBSD$");
46
47 #include "dhcpd.h"
48 #include "privsep.h"
49
50 #include <sys/ioctl.h>
51
52 #include <assert.h>
53 #include <net/if_media.h>
54 #include <ifaddrs.h>
55 #include <poll.h>
56
57 /* Assert that pointer p is aligned to at least align bytes */
58 #define assert_aligned(p, align) assert((((uintptr_t)p) & ((align) - 1)) == 0)
59
60 static struct protocol *protocols;
61 static struct timeout *timeouts;
62 static struct timeout *free_timeouts;
63 static int interfaces_invalidated;
64 void (*bootp_packet_handler)(struct interface_info *,
65 struct dhcp_packet *, int, unsigned int,
66 struct iaddr, struct hardware *);
67
68 static int interface_status(struct interface_info *ifinfo);
69
70 /*
71 * Use getifaddrs() to get a list of all the attached interfaces. For
72 * each interface that's of type INET and not the loopback interface,
73 * register that interface with the network I/O software, figure out
74 * what subnet it's on, and add it to the list of interfaces.
75 */
76 void
discover_interfaces(struct interface_info * iface)77 discover_interfaces(struct interface_info *iface)
78 {
79 struct ifaddrs *ifap, *ifa;
80 struct ifreq *tif;
81
82 if (getifaddrs(&ifap) != 0)
83 error("getifaddrs failed");
84
85 for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
86 if ((ifa->ifa_flags & IFF_LOOPBACK) ||
87 (ifa->ifa_flags & IFF_POINTOPOINT) ||
88 (!(ifa->ifa_flags & IFF_UP)))
89 continue;
90
91 if (strcmp(iface->name, ifa->ifa_name))
92 continue;
93
94 /*
95 * If we have the capability, extract link information
96 * and record it in a linked list.
97 */
98 if (ifa->ifa_addr->sa_family == AF_LINK) {
99 struct sockaddr_dl *foo;
100
101 /*
102 * The implementation of getifaddrs should guarantee
103 * this alignment
104 */
105 assert_aligned(ifa->ifa_addr,
106 _Alignof(struct sockaddr_dl));
107 #ifdef __clang__
108 #pragma clang diagnostic push
109 #pragma clang diagnostic ignored "-Wcast-align"
110 #endif
111 foo = (struct sockaddr_dl *)ifa->ifa_addr;
112 #ifdef __clang__
113 #pragma clang diagnostic pop
114 #endif
115
116 iface->index = foo->sdl_index;
117 iface->hw_address.hlen = foo->sdl_alen;
118 iface->hw_address.htype = HTYPE_ETHER; /* XXX */
119 memcpy(iface->hw_address.haddr,
120 LLADDR(foo), foo->sdl_alen);
121 } else if (ifa->ifa_addr->sa_family == AF_INET) {
122 struct sockaddr_in foo;
123 struct iaddr addr;
124
125 memcpy(&foo, ifa->ifa_addr, sizeof(foo));
126 if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK))
127 continue;
128 if (!iface->ifp) {
129 if ((tif = calloc(1, sizeof(struct ifreq)))
130 == NULL)
131 error("no space to remember ifp");
132 strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ);
133 memcpy(&tif->ifr_addr, ifa->ifa_addr,
134 ifa->ifa_addr->sa_len);
135 iface->ifp = tif;
136 iface->primary_address = foo.sin_addr;
137 }
138 addr.len = 4;
139 memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len);
140 }
141 }
142
143 if (!iface->ifp)
144 error("%s: not found", iface->name);
145
146 /* Register the interface... */
147 if_register_receive(iface);
148 if_register_send(iface);
149 add_protocol(iface->name, iface->rfdesc, got_one, iface);
150 freeifaddrs(ifap);
151 }
152
153 void
reinitialize_interfaces(void)154 reinitialize_interfaces(void)
155 {
156 interfaces_invalidated = 1;
157 }
158
159 /*
160 * Wait for packets to come in using poll(). When a packet comes in,
161 * call receive_packet to receive the packet and possibly strip hardware
162 * addressing information from it, and then call through the
163 * bootp_packet_handler hook to try to do something with it.
164 */
165 void
dispatch(void)166 dispatch(void)
167 {
168 int count, live_interfaces, i, to_msec, nfds = 0;
169 struct protocol *l;
170 struct pollfd *fds;
171 time_t howlong;
172
173 for (l = protocols; l; l = l->next)
174 nfds++;
175
176 fds = malloc(nfds * sizeof(struct pollfd));
177 if (fds == NULL)
178 error("Can't allocate poll structures.");
179
180 do {
181 /*
182 * Call any expired timeouts, and then if there's still
183 * a timeout registered, time out the select call then.
184 */
185 another:
186 if (timeouts) {
187 struct timeout *t;
188
189 if (timeouts->when <= cur_time) {
190 t = timeouts;
191 timeouts = timeouts->next;
192 (*(t->func))(t->what);
193 t->next = free_timeouts;
194 free_timeouts = t;
195 goto another;
196 }
197
198 /*
199 * Figure timeout in milliseconds, and check for
200 * potential overflow, so we can cram into an
201 * int for poll, while not polling with a
202 * negative timeout and blocking indefinitely.
203 */
204 howlong = timeouts->when - cur_time;
205 if (howlong > INT_MAX / 1000)
206 howlong = INT_MAX / 1000;
207 to_msec = howlong * 1000;
208 } else
209 to_msec = -1;
210
211 /* Set up the descriptors to be polled. */
212 live_interfaces = 0;
213 for (i = 0, l = protocols; l; l = l->next) {
214 struct interface_info *ip = l->local;
215
216 if (ip == NULL || ip->dead)
217 continue;
218 fds[i].fd = l->fd;
219 fds[i].events = POLLIN;
220 fds[i].revents = 0;
221 i++;
222 if (l->handler == got_one)
223 live_interfaces++;
224 }
225 if (live_interfaces == 0)
226 error("No live interfaces to poll on - exiting.");
227
228 /* Wait for a packet or a timeout... XXX */
229 count = poll(fds, nfds, to_msec);
230
231 /* Not likely to be transitory... */
232 if (count == -1) {
233 if (errno == EAGAIN || errno == EINTR) {
234 time(&cur_time);
235 continue;
236 } else
237 error("poll: %m");
238 }
239
240 /* Get the current time... */
241 time(&cur_time);
242
243 i = 0;
244 for (l = protocols; l; l = l->next) {
245 struct interface_info *ip;
246 ip = l->local;
247 if ((fds[i].revents & (POLLIN | POLLHUP))) {
248 fds[i].revents = 0;
249 if (ip && (l->handler != got_one ||
250 !ip->dead))
251 (*(l->handler))(l);
252 if (interfaces_invalidated)
253 break;
254 }
255 i++;
256 }
257 interfaces_invalidated = 0;
258 } while (1);
259 }
260
261
262 void
got_one(struct protocol * l)263 got_one(struct protocol *l)
264 {
265 struct sockaddr_in from;
266 struct hardware hfrom;
267 struct iaddr ifrom;
268 ssize_t result;
269 union {
270 /*
271 * Packet input buffer. Must be as large as largest
272 * possible MTU.
273 */
274 unsigned char packbuf[4095];
275 struct dhcp_packet packet;
276 } u;
277 struct interface_info *ip = l->local;
278
279 if ((result = receive_packet(ip, u.packbuf, sizeof(u), &from,
280 &hfrom)) == -1) {
281 warning("receive_packet failed on %s: %s", ip->name,
282 strerror(errno));
283 ip->errors++;
284 if ((!interface_status(ip)) ||
285 (ip->noifmedia && ip->errors > 20)) {
286 /* our interface has gone away. */
287 warning("Interface %s no longer appears valid.",
288 ip->name);
289 ip->dead = 1;
290 interfaces_invalidated = 1;
291 close(l->fd);
292 remove_protocol(l);
293 free(ip);
294 }
295 return;
296 }
297 if (result == 0)
298 return;
299
300 if (bootp_packet_handler) {
301 ifrom.len = 4;
302 memcpy(ifrom.iabuf, &from.sin_addr, ifrom.len);
303
304 (*bootp_packet_handler)(ip, &u.packet, result,
305 from.sin_port, ifrom, &hfrom);
306 }
307 }
308
309 int
interface_status(struct interface_info * ifinfo)310 interface_status(struct interface_info *ifinfo)
311 {
312 char *ifname = ifinfo->name;
313 int ifsock = ifinfo->rfdesc;
314 struct ifreq ifr;
315 struct ifmediareq ifmr;
316
317 /* get interface flags */
318 memset(&ifr, 0, sizeof(ifr));
319 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
320 if (ioctl(ifsock, SIOCGIFFLAGS, &ifr) < 0) {
321 cap_syslog(capsyslog, LOG_ERR, "ioctl(SIOCGIFFLAGS) on %s: %m",
322 ifname);
323 goto inactive;
324 }
325
326 /*
327 * if one of UP and RUNNING flags is dropped,
328 * the interface is not active.
329 */
330 if ((ifr.ifr_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
331 goto inactive;
332
333 /* Next, check carrier on the interface, if possible */
334 if (ifinfo->noifmedia)
335 goto active;
336 memset(&ifmr, 0, sizeof(ifmr));
337 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
338 if (ioctl(ifsock, SIOCGIFMEDIA, (caddr_t)&ifmr) < 0) {
339 if (errno != EINVAL) {
340 cap_syslog(capsyslog, LOG_DEBUG,
341 "ioctl(SIOCGIFMEDIA) on %s: %m", ifname);
342 ifinfo->noifmedia = 1;
343 goto active;
344 }
345 /*
346 * EINVAL (or ENOTTY) simply means that the interface
347 * does not support the SIOCGIFMEDIA ioctl. We regard it alive.
348 */
349 ifinfo->noifmedia = 1;
350 goto active;
351 }
352 if (ifmr.ifm_status & IFM_AVALID) {
353 switch (ifmr.ifm_active & IFM_NMASK) {
354 case IFM_ETHER:
355 case IFM_IEEE80211:
356 if (ifmr.ifm_status & IFM_ACTIVE)
357 goto active;
358 else
359 goto inactive;
360 break;
361 default:
362 goto inactive;
363 }
364 }
365 inactive:
366 return (0);
367 active:
368 return (1);
369 }
370
371 void
add_timeout(time_t when,void (* where)(void *),void * what)372 add_timeout(time_t when, void (*where)(void *), void *what)
373 {
374 struct timeout *t, *q;
375
376 /* See if this timeout supersedes an existing timeout. */
377 t = NULL;
378 for (q = timeouts; q; q = q->next) {
379 if (q->func == where && q->what == what) {
380 if (t)
381 t->next = q->next;
382 else
383 timeouts = q->next;
384 break;
385 }
386 t = q;
387 }
388
389 /* If we didn't supersede a timeout, allocate a timeout
390 structure now. */
391 if (!q) {
392 if (free_timeouts) {
393 q = free_timeouts;
394 free_timeouts = q->next;
395 q->func = where;
396 q->what = what;
397 } else {
398 q = malloc(sizeof(struct timeout));
399 if (!q)
400 error("Can't allocate timeout structure!");
401 q->func = where;
402 q->what = what;
403 }
404 }
405
406 q->when = when;
407
408 /* Now sort this timeout into the timeout list. */
409
410 /* Beginning of list? */
411 if (!timeouts || timeouts->when > q->when) {
412 q->next = timeouts;
413 timeouts = q;
414 return;
415 }
416
417 /* Middle of list? */
418 for (t = timeouts; t->next; t = t->next) {
419 if (t->next->when > q->when) {
420 q->next = t->next;
421 t->next = q;
422 return;
423 }
424 }
425
426 /* End of list. */
427 t->next = q;
428 q->next = NULL;
429 }
430
431 void
cancel_timeout(void (* where)(void *),void * what)432 cancel_timeout(void (*where)(void *), void *what)
433 {
434 struct timeout *t, *q;
435
436 /* Look for this timeout on the list, and unlink it if we find it. */
437 t = NULL;
438 for (q = timeouts; q; q = q->next) {
439 if (q->func == where && q->what == what) {
440 if (t)
441 t->next = q->next;
442 else
443 timeouts = q->next;
444 break;
445 }
446 t = q;
447 }
448
449 /* If we found the timeout, put it on the free list. */
450 if (q) {
451 q->next = free_timeouts;
452 free_timeouts = q;
453 }
454 }
455
456 /* Add a protocol to the list of protocols... */
457 void
add_protocol(const char * name,int fd,void (* handler)(struct protocol *),void * local)458 add_protocol(const char *name, int fd, void (*handler)(struct protocol *),
459 void *local)
460 {
461 struct protocol *p;
462
463 p = malloc(sizeof(*p));
464 if (!p)
465 error("can't allocate protocol struct for %s", name);
466
467 p->fd = fd;
468 p->handler = handler;
469 p->local = local;
470 p->next = protocols;
471 protocols = p;
472 }
473
474 void
remove_protocol(struct protocol * proto)475 remove_protocol(struct protocol *proto)
476 {
477 struct protocol *p, *next;
478
479 for (p = protocols; p; p = next) {
480 next = p->next;
481 if (p == proto) {
482 protocols = p->next;
483 free(p);
484 }
485 }
486 }
487
488 int
interface_link_status(char * ifname)489 interface_link_status(char *ifname)
490 {
491 struct ifmediareq ifmr;
492 int sock;
493
494 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
495 error("Can't create socket");
496
497 memset(&ifmr, 0, sizeof(ifmr));
498 strlcpy(ifmr.ifm_name, ifname, sizeof(ifmr.ifm_name));
499 if (ioctl(sock, SIOCGIFMEDIA, (caddr_t)&ifmr) == -1) {
500 /* EINVAL -> link state unknown. treat as active */
501 if (errno != EINVAL)
502 cap_syslog(capsyslog, LOG_DEBUG,
503 "ioctl(SIOCGIFMEDIA) on %s: %m", ifname);
504 close(sock);
505 return (1);
506 }
507 close(sock);
508
509 if (ifmr.ifm_status & IFM_AVALID) {
510 switch (ifmr.ifm_active & IFM_NMASK) {
511 case IFM_ETHER:
512 case IFM_IEEE80211:
513 if (ifmr.ifm_status & IFM_ACTIVE)
514 return (1);
515 else
516 return (0);
517 }
518 }
519 return (1);
520 }
521
522 void
interface_set_mtu_unpriv(int privfd,u_int16_t mtu)523 interface_set_mtu_unpriv(int privfd, u_int16_t mtu)
524 {
525 struct imsg_hdr hdr;
526 struct buf *buf;
527 int errs = 0;
528
529 hdr.code = IMSG_SET_INTERFACE_MTU;
530 hdr.len = sizeof(hdr) +
531 sizeof(u_int16_t);
532
533 if ((buf = buf_open(hdr.len)) == NULL)
534 error("buf_open: %m");
535
536 errs += buf_add(buf, &hdr, sizeof(hdr));
537 errs += buf_add(buf, &mtu, sizeof(mtu));
538 if (errs)
539 error("buf_add: %m");
540
541 if (buf_close(privfd, buf) == -1)
542 error("buf_close: %m");
543 }
544
545 void
interface_set_mtu_priv(char * ifname,u_int16_t mtu)546 interface_set_mtu_priv(char *ifname, u_int16_t mtu)
547 {
548 struct ifreq ifr;
549 int sock;
550 u_int16_t old_mtu;
551
552 if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
553 error("Can't create socket");
554
555 memset(&ifr, 0, sizeof(ifr));
556 old_mtu = 0;
557
558 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
559
560 if (ioctl(sock, SIOCGIFMTU, (caddr_t)&ifr) == -1)
561 warning("SIOCGIFMTU failed (%s): %s", ifname,
562 strerror(errno));
563 else
564 old_mtu = ifr.ifr_mtu;
565
566 if (mtu != old_mtu) {
567 ifr.ifr_mtu = mtu;
568
569 if (ioctl(sock, SIOCSIFMTU, &ifr) == -1)
570 warning("SIOCSIFMTU failed (%d): %s", mtu,
571 strerror(errno));
572 }
573
574 close(sock);
575 }
576