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