xref: /netbsd-src/external/mpl/dhcp/dist/common/bpf.c (revision f407d9293b6650aa8c33d6a995f797bb6aaefd90)
1 /*	$NetBSD: bpf.c,v 1.5 2022/04/03 01:10:58 christos Exp $	*/
2 
3 /* bpf.c
4 
5    BPF socket interface code, originally contributed by Archie Cobbs. */
6 
7 /*
8  * Copyright (C) 2004-2022 Internet Systems Consortium, Inc. ("ISC")
9  * Copyright (c) 1996-2003 by Internet Software Consortium
10  *
11  * This Source Code Form is subject to the terms of the Mozilla Public
12  * License, v. 2.0. If a copy of the MPL was not distributed with this
13  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
16  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
17  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
18  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
19  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
20  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
21  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
22  *
23  *   Internet Systems Consortium, Inc.
24  *   PO Box 360
25  *   Newmarket, NH 03857 USA
26  *   <info@isc.org>
27  *   https://www.isc.org/
28  *
29  * This software was contributed to Internet Systems Consortium
30  * by Archie Cobbs.
31  *
32  * Patches for FDDI support on Digital Unix were written by Bill
33  * Stapleton, and maintained for a while by Mike Meredith before he
34  * managed to get me to integrate them.
35  */
36 
37 #include <sys/cdefs.h>
38 __RCSID("$NetBSD: bpf.c,v 1.5 2022/04/03 01:10:58 christos Exp $");
39 
40 #include "dhcpd.h"
41 #if defined (USE_BPF_SEND) || defined (USE_BPF_RECEIVE)	\
42 				|| defined (USE_LPF_RECEIVE)
43 # if defined (USE_LPF_RECEIVE)
44 #  include <asm/types.h>
45 #  include <linux/filter.h>
46 #  define bpf_insn sock_filter /* Linux: dare to be gratuitously different. */
47 # else
48 #  include <sys/ioctl.h>
49 #  include <sys/uio.h>
50 #  include <net/bpf.h>
51 #  if defined (NEED_OSF_PFILT_HACKS)
52 #   include <net/pfilt.h>
53 #  endif
54 # endif
55 
56 #include <sys/param.h>
57 #include <netinet/in_systm.h>
58 #include "includes/netinet/ip.h"
59 #include "includes/netinet/udp.h"
60 #include "includes/netinet/if_ether.h"
61 #endif
62 
63 #if defined(USE_BPF_SEND) || defined(USE_BPF_RECEIVE) || defined(USE_BPF_HWADDR)
64 #include <net/if_types.h>
65 #include <ifaddrs.h>
66 #endif
67 
68 #include <errno.h>
69 
70 /* Reinitializes the specified interface after an address change.   This
71    is not required for packet-filter APIs. */
72 
73 #ifdef USE_BPF_SEND
if_reinitialize_send(info)74 void if_reinitialize_send (info)
75 	struct interface_info *info;
76 {
77 }
78 #endif
79 
80 #ifdef USE_BPF_RECEIVE
if_reinitialize_receive(info)81 void if_reinitialize_receive (info)
82 	struct interface_info *info;
83 {
84 }
85 #endif
86 
87 /* Called by get_interface_list for each interface that's discovered.
88    Opens a packet filter for each interface and adds it to the select
89    mask. */
90 
91 #if defined (USE_BPF_SEND) || defined (USE_BPF_RECEIVE)
if_register_bpf(info)92 int if_register_bpf (info)
93 	struct interface_info *info;
94 {
95 	int sock;
96 	char filename[50];
97 	int b;
98 
99 	/* Open a BPF device */
100 	for (b = 0; 1; b++) {
101 		/* %Audit% 31 bytes max. %2004.06.17,Safe% */
102 		sprintf(filename, BPF_FORMAT, b);
103 		sock = open (filename, O_RDWR, 0);
104 		if (sock < 0) {
105 			if (errno == EBUSY) {
106 				continue;
107 			} else {
108 				if (!b)
109 					log_fatal ("No bpf devices.%s%s%s",
110 					       "   Please read the README",
111 					       " section for your operating",
112 					       " system.");
113 				log_fatal ("Can't find free bpf: %m");
114 			}
115 		} else {
116 			break;
117 		}
118 	}
119 
120 	/* Set the BPF device to point at this interface. */
121 	if (ioctl (sock, BIOCSETIF, info -> ifp) < 0)
122 		log_fatal ("Can't attach interface %s to bpf device %s: %m",
123 		       info -> name, filename);
124 
125 	get_hw_addr(info->name, &info->hw_address);
126 
127 	return sock;
128 }
129 #endif /* USE_BPF_SEND || USE_BPF_RECEIVE */
130 
131 #ifdef USE_BPF_SEND
if_register_send(info)132 void if_register_send (info)
133 	struct interface_info *info;
134 {
135 	/* If we're using the bpf API for sending and receiving,
136 	   we don't need to register this interface twice. */
137 #ifndef USE_BPF_RECEIVE
138 	info -> wfdesc = if_register_bpf (info, interface);
139 #else
140 	info -> wfdesc = info -> rfdesc;
141 #endif
142 	if (!quiet_interface_discovery)
143 		log_info ("Sending on   BPF/%s/%s%s%s",
144 		      info -> name,
145 		      print_hw_addr (info -> hw_address.hbuf [0],
146 				     info -> hw_address.hlen - 1,
147 				     &info -> hw_address.hbuf [1]),
148 		      (info -> shared_network ? "/" : ""),
149 		      (info -> shared_network ?
150 		       info -> shared_network -> name : ""));
151 }
152 
if_deregister_send(info)153 void if_deregister_send (info)
154 	struct interface_info *info;
155 {
156 	/* If we're using the bpf API for sending and receiving,
157 	   we don't need to register this interface twice. */
158 #ifndef USE_BPF_RECEIVE
159 	close (info -> wfdesc);
160 #endif
161 	info -> wfdesc = -1;
162 
163 	if (!quiet_interface_discovery)
164 		log_info ("Disabling output on BPF/%s/%s%s%s",
165 		      info -> name,
166 		      print_hw_addr (info -> hw_address.hbuf [0],
167 				     info -> hw_address.hlen - 1,
168 				     &info -> hw_address.hbuf [1]),
169 		      (info -> shared_network ? "/" : ""),
170 		      (info -> shared_network ?
171 		       info -> shared_network -> name : ""));
172 }
173 #endif /* USE_BPF_SEND */
174 
175 #if defined (USE_BPF_RECEIVE) || defined (USE_LPF_RECEIVE)
176 /* Packet filter program...
177    XXX Changes to the filter program may require changes to the constant
178    offsets used in if_register_send to patch the BPF program! XXX */
179 
180 struct bpf_insn dhcp_bpf_filter [] = {
181 	/* Make sure this is an IP packet... */
182 	BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 12),
183 	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8),
184 
185 	/* Make sure it's a UDP packet... */
186 	BPF_STMT (BPF_LD + BPF_B + BPF_ABS, 23),
187 	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6),
188 
189 	/* Make sure this isn't a fragment... */
190 	BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20),
191 	BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0),
192 
193 	/* Get the IP header length... */
194 	BPF_STMT (BPF_LDX + BPF_B + BPF_MSH, 14),
195 
196 	/* Make sure it's to the right port... */
197 	BPF_STMT (BPF_LD + BPF_H + BPF_IND, 16),
198 	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, 67, 0, 1),             /* patch */
199 
200 	/* If we passed all the tests, ask for the whole packet. */
201 	BPF_STMT (BPF_RET + BPF_K, (u_int)-1),
202 
203 	/* Otherwise, drop it. */
204 	BPF_STMT (BPF_RET + BPF_K, 0),
205 };
206 
207 #if defined(RELAY_PORT)
208 /*
209  * For relay port extension
210  */
211 struct bpf_insn dhcp_bpf_relay_filter [] = {
212 	/* Make sure this is an IP packet... */
213 	BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 12),
214 	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 10),
215 
216 	/* Make sure it's a UDP packet... */
217 	BPF_STMT (BPF_LD + BPF_B + BPF_ABS, 23),
218 	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 8),
219 
220 	/* Make sure this isn't a fragment... */
221 	BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20),
222 	BPF_JUMP(BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 6, 0),
223 
224 	/* Get the IP header length... */
225 	BPF_STMT (BPF_LDX + BPF_B + BPF_MSH, 14),
226 
227 	/* Make sure it's to the right port... */
228 	BPF_STMT (BPF_LD + BPF_H + BPF_IND, 16),
229 	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, 67, 2, 0),             /* patch */
230 
231 	/* relay can have an alternative port... */
232 	BPF_STMT (BPF_LD + BPF_H + BPF_IND, 16),
233 	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, 67, 0, 1),             /* patch */
234 
235 	/* If we passed all the tests, ask for the whole packet. */
236 	BPF_STMT (BPF_RET + BPF_K, (u_int)-1),
237 
238 	/* Otherwise, drop it. */
239 	BPF_STMT (BPF_RET + BPF_K, 0),
240 };
241 
242 int dhcp_bpf_relay_filter_len =
243 	sizeof dhcp_bpf_relay_filter / sizeof (struct bpf_insn);
244 #endif
245 
246 #if defined (DEC_FDDI)
247 struct bpf_insn *bpf_fddi_filter = NULL;
248 #endif
249 
250 int dhcp_bpf_filter_len = sizeof dhcp_bpf_filter / sizeof (struct bpf_insn);
251 #if defined (HAVE_TR_SUPPORT)
252 struct bpf_insn dhcp_bpf_tr_filter [] = {
253         /* accept all token ring packets due to variable length header */
254         /* if we want to get clever, insert the program here */
255 
256 	/* If we passed all the tests, ask for the whole packet. */
257 	BPF_STMT(BPF_RET+BPF_K, (u_int)-1),
258 
259 	/* Otherwise, drop it. */
260 	BPF_STMT(BPF_RET+BPF_K, 0),
261 };
262 
263 int dhcp_bpf_tr_filter_len = (sizeof dhcp_bpf_tr_filter /
264 			      sizeof (struct bpf_insn));
265 #endif /* HAVE_TR_SUPPORT */
266 #endif /* USE_LPF_RECEIVE || USE_BPF_RECEIVE */
267 
268 #if defined (USE_BPF_RECEIVE)
if_register_receive(info)269 void if_register_receive (info)
270 	struct interface_info *info;
271 {
272 	int flag = 1;
273 	struct bpf_version v;
274 	struct bpf_program p;
275 #ifdef NEED_OSF_PFILT_HACKS
276 	u_int32_t bits;
277 #endif
278 #ifdef DEC_FDDI
279 	int link_layer;
280 #endif /* DEC_FDDI */
281 
282 	/* Open a BPF device and hang it on this interface... */
283 	info -> rfdesc = if_register_bpf (info);
284 
285 	/* Make sure the BPF version is in range... */
286 	if (ioctl (info -> rfdesc, BIOCVERSION, &v) < 0)
287 		log_fatal ("Can't get BPF version: %m");
288 
289 	if (v.bv_major != BPF_MAJOR_VERSION ||
290 	    v.bv_minor < BPF_MINOR_VERSION)
291 		log_fatal ("BPF version mismatch - recompile DHCP!");
292 
293 	/* Set immediate mode so that reads return as soon as a packet
294 	   comes in, rather than waiting for the input buffer to fill with
295 	   packets. */
296 	if (ioctl (info -> rfdesc, BIOCIMMEDIATE, &flag) < 0)
297 		log_fatal ("Can't set immediate mode on bpf device: %m");
298 
299 #ifdef NEED_OSF_PFILT_HACKS
300 	/* Allow the copyall flag to be set... */
301 	if (ioctl(info -> rfdesc, EIOCALLOWCOPYALL, &flag) < 0)
302 		log_fatal ("Can't set ALLOWCOPYALL: %m");
303 
304 	/* Clear all the packet filter mode bits first... */
305 	bits = 0;
306 	if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
307 		log_fatal ("Can't clear pfilt bits: %m");
308 
309 	/* Set the ENBATCH, ENCOPYALL, ENBPFHDR bits... */
310 	bits = ENBATCH | ENCOPYALL | ENBPFHDR;
311 	if (ioctl (info -> rfdesc, EIOCMBIS, &bits) < 0)
312 		log_fatal ("Can't set ENBATCH|ENCOPYALL|ENBPFHDR: %m");
313 #endif
314 	/* Get the required BPF buffer length from the kernel. */
315 	if (ioctl (info -> rfdesc, BIOCGBLEN, &info -> rbuf_max) < 0)
316 		log_fatal ("Can't get bpf buffer length: %m");
317 	info -> rbuf = dmalloc (info -> rbuf_max, MDL);
318 	if (!info -> rbuf)
319 		log_fatal ("Can't allocate %ld bytes for bpf input buffer.",
320 			   (long)(info -> rbuf_max));
321 	info -> rbuf_offset = 0;
322 	info -> rbuf_len = 0;
323 
324 	/* Set up the bpf filter program structure. */
325 	p.bf_len = dhcp_bpf_filter_len;
326 
327 #ifdef DEC_FDDI
328 	/* See if this is an FDDI interface, flag it for later. */
329 	if (ioctl(info -> rfdesc, BIOCGDLT, &link_layer) >= 0 &&
330 	    link_layer == DLT_FDDI) {
331 		if (!bpf_fddi_filter) {
332 			bpf_fddi_filter = dmalloc (sizeof dhcp_bpf_filter,
333 						    MDL);
334 			if (!bpf_fddi_filter)
335 				log_fatal ("No memory for FDDI filter.");
336 			memcpy (bpf_fddi_filter,
337 				dhcp_bpf_filter, sizeof dhcp_bpf_filter);
338 			/* Patch the BPF program to account for the difference
339 			   in length between ethernet headers (14), FDDI and
340 			   802.2 headers (16 +8=24, +10).
341 			   XXX changes to filter program may require changes to
342 			   XXX the insn number(s) used below! */
343 			bpf_fddi_filter[0].k += 10;
344 			bpf_fddi_filter[2].k += 10;
345 			bpf_fddi_filter[4].k += 10;
346 			bpf_fddi_filter[6].k += 10;
347 			bpf_fddi_filter[7].k += 10;
348 		}
349 		p.bf_insns = bpf_fddi_filter;
350 	} else
351 #endif /* DEC_FDDI */
352 	p.bf_insns = dhcp_bpf_filter;
353 
354         /* Patch the server port into the BPF  program...
355 	   XXX changes to filter program may require changes
356 	   to the insn number(s) used below! XXX */
357 #if defined(RELAY_PORT)
358 	if (relay_port) {
359 		/*
360 		 * If user defined relay UDP port, we need to filter
361 		 * also on the user UDP port.
362 		 */
363 		p.bf_len = dhcp_bpf_relay_filter_len;
364 		p.bf_insns = dhcp_bpf_relay_filter;
365 
366 		dhcp_bpf_relay_filter [10].k = ntohs (relay_port);
367 	}
368 #endif
369 	p.bf_insns [8].k = ntohs (*libdhcp_callbacks.local_port);
370 
371 	if (ioctl (info -> rfdesc, BIOCSETF, &p) < 0)
372 		log_fatal ("Can't install packet filter program: %m");
373 	if (!quiet_interface_discovery)
374 		log_info ("Listening on BPF/%s/%s%s%s",
375 		      info -> name,
376 		      print_hw_addr (info -> hw_address.hbuf [0],
377 				     info -> hw_address.hlen - 1,
378 				     &info -> hw_address.hbuf [1]),
379 		      (info -> shared_network ? "/" : ""),
380 		      (info -> shared_network ?
381 		       info -> shared_network -> name : ""));
382 }
383 
if_deregister_receive(info)384 void if_deregister_receive (info)
385 	struct interface_info *info;
386 {
387 	close (info -> rfdesc);
388 	info -> rfdesc = -1;
389 
390 	if (!quiet_interface_discovery)
391 		log_info ("Disabling input on BPF/%s/%s%s%s",
392 		      info -> name,
393 		      print_hw_addr (info -> hw_address.hbuf [0],
394 				     info -> hw_address.hlen - 1,
395 				     &info -> hw_address.hbuf [1]),
396 		      (info -> shared_network ? "/" : ""),
397 		      (info -> shared_network ?
398 		       info -> shared_network -> name : ""));
399 }
400 #endif /* USE_BPF_RECEIVE */
401 
402 #ifdef USE_BPF_SEND
send_packet(interface,packet,raw,len,from,to,hto)403 ssize_t send_packet (interface, packet, raw, len, from, to, hto)
404 	struct interface_info *interface;
405 	struct packet *packet;
406 	struct dhcp_packet *raw;
407 	size_t len;
408 	struct in_addr from;
409 	struct sockaddr_in *to;
410 	struct hardware *hto;
411 {
412 	unsigned hbufp = 0, ibufp = 0;
413 	double hw [4];
414 	double ip [32];
415 	struct iovec iov [3];
416 	int result;
417 
418 	if (!strcmp (interface -> name, "fallback"))
419 		return send_fallback (interface, packet, raw,
420 				      len, from, to, hto);
421 
422 	if (hto == NULL && interface->anycast_mac_addr.hlen)
423 		hto = &interface->anycast_mac_addr;
424 
425 	/* Assemble the headers... */
426 	assemble_hw_header (interface, (unsigned char *)hw, &hbufp, hto);
427 	assemble_udp_ip_header (interface,
428 				(unsigned char *)ip, &ibufp, from.s_addr,
429 				to -> sin_addr.s_addr, to -> sin_port,
430 				(unsigned char *)raw, len);
431 
432 	/* Fire it off */
433 	iov [0].iov_base = ((char *)hw);
434 	iov [0].iov_len = hbufp;
435 	iov [1].iov_base = ((char *)ip);
436 	iov [1].iov_len = ibufp;
437 	iov [2].iov_base = (char *)raw;
438 	iov [2].iov_len = len;
439 
440 	result = writev(interface -> wfdesc, iov, 3);
441 	if (result < 0)
442 		log_error ("send_packet: %m");
443 	return result;
444 }
445 #endif /* USE_BPF_SEND */
446 
447 #ifdef USE_BPF_RECEIVE
receive_packet(interface,buf,len,from,hfrom)448 ssize_t receive_packet (interface, buf, len, from, hfrom)
449 	struct interface_info *interface;
450 	unsigned char *buf;
451 	size_t len;
452 	struct sockaddr_in *from;
453 	struct hardware *hfrom;
454 {
455 	int length = 0;
456 	int offset = 0;
457 	struct bpf_hdr hdr;
458 	unsigned paylen;
459 
460 	/* All this complexity is because BPF doesn't guarantee
461 	   that only one packet will be returned at a time.   We're
462 	   getting what we deserve, though - this is a terrible abuse
463 	   of the BPF interface.   Sigh. */
464 
465 	/* Process packets until we get one we can return or until we've
466 	   done a read and gotten nothing we can return... */
467 
468 	/* If the buffer is empty, fill it. */
469 	if (interface->rbuf_offset >= interface->rbuf_len) {
470 		length = read(interface->rfdesc, interface->rbuf,
471 			      (size_t)interface->rbuf_max);
472 		if (length <= 0) {
473 #ifdef __FreeBSD__
474 			if (errno == ENXIO) {
475 #else
476 			if (errno == EIO) {
477 #endif
478 				dhcp_interface_remove
479 					((omapi_object_t *)interface, NULL);
480 			}
481 			return (length);
482 		}
483 		interface->rbuf_offset = 0;
484 		interface->rbuf_len = BPF_WORDALIGN(length);
485 	}
486 
487 	do {
488 		/* If there isn't room for a whole bpf header, something went
489 		   wrong, but we'll ignore it and hope it goes away... XXX */
490 		if (interface->rbuf_len -
491 		    interface->rbuf_offset < sizeof hdr) {
492 			interface->rbuf_offset = interface->rbuf_len;
493 			continue;
494 		}
495 
496 		/* Copy out a bpf header... */
497 		memcpy(&hdr, &interface->rbuf[interface->rbuf_offset],
498 		       sizeof hdr);
499 
500 		/* If the bpf header plus data doesn't fit in what's left
501 		   of the buffer, stick head in sand yet again... */
502 		if (interface->rbuf_offset +
503 		    hdr.bh_hdrlen + hdr.bh_caplen > interface->rbuf_len) {
504 			interface->rbuf_offset = interface->rbuf_len;
505 			continue;
506 		}
507 
508 		/* If the captured data wasn't the whole packet, or if
509 		   the packet won't fit in the input buffer, all we
510 		   can do is drop it. */
511 		if (hdr.bh_caplen != hdr.bh_datalen) {
512 			interface->rbuf_offset =
513 				BPF_WORDALIGN(interface->rbuf_offset +
514 					      hdr.bh_hdrlen + hdr.bh_caplen);
515 			continue;
516 		}
517 
518 		/* Skip over the BPF header... */
519 		interface->rbuf_offset += hdr.bh_hdrlen;
520 
521 		/* Decode the physical header... */
522 		offset = decode_hw_header(interface, interface->rbuf,
523 					  interface->rbuf_offset, hfrom);
524 
525 		/* If a physical layer checksum failed (dunno of any
526 		   physical layer that supports this, but WTH), skip this
527 		   packet. */
528 		if (offset < 0) {
529 			interface->rbuf_offset =
530 				BPF_WORDALIGN(interface->rbuf_offset +
531 					      hdr.bh_caplen);
532 			continue;
533 		}
534 		interface->rbuf_offset += offset;
535 		hdr.bh_caplen -= offset;
536 
537 		/* Decode the IP and UDP headers... */
538 		offset = decode_udp_ip_header(interface, interface->rbuf,
539 					      interface->rbuf_offset,
540                                               from, hdr.bh_caplen, &paylen, 1);
541 
542 		/* If the IP or UDP checksum was bad, skip the packet... */
543 		if (offset < 0) {
544 			interface->rbuf_offset =
545 				BPF_WORDALIGN(interface->rbuf_offset +
546 					      hdr.bh_caplen);
547 			continue;
548 		}
549 		interface->rbuf_offset = interface->rbuf_offset + offset;
550 		hdr.bh_caplen -= offset;
551 
552 		/* If there's not enough room to stash the packet data,
553 		   we have to skip it (this shouldn't happen in real
554 		   life, though). */
555 		if (hdr.bh_caplen > len) {
556 			interface->rbuf_offset =
557 				BPF_WORDALIGN(interface->rbuf_offset +
558 					       hdr.bh_caplen);
559 			continue;
560 		}
561 
562 		/* Copy out the data in the packet... */
563 		memcpy(buf, interface->rbuf + interface->rbuf_offset, paylen);
564 		interface->rbuf_offset =
565 			BPF_WORDALIGN(interface->rbuf_offset + hdr.bh_caplen);
566 		return paylen;
567 	} while (interface->rbuf_offset < interface->rbuf_len);
568 
569 	return (0);
570 }
571 
can_unicast_without_arp(ip)572 int can_unicast_without_arp (ip)
573 	struct interface_info *ip;
574 {
575 	return 1;
576 }
577 
can_receive_unicast_unconfigured(ip)578 int can_receive_unicast_unconfigured (ip)
579 	struct interface_info *ip;
580 {
581 	return 1;
582 }
583 
supports_multiple_interfaces(ip)584 int supports_multiple_interfaces (ip)
585 	struct interface_info *ip;
586 {
587 	return 1;
588 }
589 
maybe_setup_fallback()590 void maybe_setup_fallback ()
591 {
592 	isc_result_t status;
593 	struct interface_info *fbi = (struct interface_info *)0;
594 	if (setup_fallback (&fbi, MDL)) {
595 		if_register_fallback (fbi);
596 		status = omapi_register_io_object ((omapi_object_t *)fbi,
597 						   if_readsocket, 0,
598 						   fallback_discard, 0, 0);
599 		if (status != ISC_R_SUCCESS)
600 			log_fatal ("Can't register I/O handle for %s: %s",
601 				   fbi -> name, isc_result_totext (status));
602 		interface_dereference (&fbi, MDL);
603 	}
604 }
605 
606 #endif
607 
608 #if defined(USE_BPF_RECEIVE) || defined(USE_BPF_HWADDR)
609 static int
lladdr_active(int s,const char * name,const struct ifaddrs * ifa)610 lladdr_active(int s, const char *name, const struct ifaddrs *ifa)
611 {
612 	if (ifa->ifa_addr->sa_family != AF_LINK)
613 		return 0;
614 	if (strcmp(ifa->ifa_name, name) != 0)
615 		return 0;
616 
617 #ifdef SIOCGLIFADDR
618 {
619 	struct if_laddrreq iflr;
620 	const struct sockaddr_dl *sdl;
621 
622 	sdl = satocsdl(ifa->ifa_addr);
623 	memset(&iflr, 0, sizeof(iflr));
624 
625 	strlcpy(iflr.iflr_name, ifa->ifa_name, sizeof(iflr.iflr_name));
626 	memcpy(&iflr.addr, ifa->ifa_addr, MIN(ifa->ifa_addr->sa_len,
627 	   sizeof(iflr.addr)));
628 	iflr.flags = IFLR_PREFIX;
629 	iflr.prefixlen = sdl->sdl_alen * NBBY;
630 
631 	if (ioctl(s, SIOCGLIFADDR, &iflr) == -1) {
632 		log_fatal("ioctl(SIOCGLIFADDR): %m");
633 	}
634 
635 	if ((iflr.flags & IFLR_ACTIVE) == 0)
636 		return 0;
637 }
638 #endif
639 	return 1;
640 }
641 
642 void
get_hw_addr(const char * name,struct hardware * hw)643 get_hw_addr(const char *name, struct hardware *hw) {
644 	struct ifaddrs *ifa;
645 	struct ifaddrs *p;
646 	struct sockaddr_dl *sa;
647 	int s;
648 
649 	if ((s = socket(AF_LINK, SOCK_DGRAM, 0)) == -1) {
650 		log_fatal("socket AF_LINK: %m");
651 	}
652 
653 	if (getifaddrs(&ifa) != 0) {
654 		log_fatal("Error getting interface information; %m");
655 	}
656 
657 	/*
658 	 * Loop through our interfaces finding a match.
659 	 */
660 	sa = NULL;
661 	for (p=ifa; (p != NULL) && (sa == NULL); p = p->ifa_next) {
662 		if (lladdr_active(s, name, p)) {
663 		    	sa = (struct sockaddr_dl *)p->ifa_addr;
664 			break;
665 		}
666 	}
667 	if (sa == NULL) {
668 		log_fatal("No interface called '%s'", name);
669 	}
670 	close(s);
671 
672 	/*
673 	 * Pull out the appropriate information.
674 	 */
675         switch (sa->sdl_type) {
676                 case IFT_ETHER:
677 #ifdef IFT_CARP
678 		case IFT_CARP:
679 #endif
680 #if defined (IFT_L2VLAN)
681 		case IFT_L2VLAN:
682 #endif
683                         hw->hlen = sa->sdl_alen + 1;
684                         hw->hbuf[0] = HTYPE_ETHER;
685                         memcpy(&hw->hbuf[1], LLADDR(sa), sa->sdl_alen);
686                         break;
687 		case IFT_ISO88023:
688 		case IFT_ISO88024: /* "token ring" */
689 		case IFT_ISO88025:
690 		case IFT_ISO88026:
691                         hw->hlen = sa->sdl_alen + 1;
692                         hw->hbuf[0] = HTYPE_IEEE802;
693                         memcpy(&hw->hbuf[1], LLADDR(sa), sa->sdl_alen);
694                         break;
695 #ifdef IFT_FDDI
696                 case IFT_FDDI:
697                         hw->hlen = sa->sdl_alen + 1;
698                         hw->hbuf[0] = HTYPE_FDDI;
699                         memcpy(&hw->hbuf[1], LLADDR(sa), sa->sdl_alen);
700                         break;
701 #endif /* IFT_FDDI */
702                 default:
703                         log_fatal("Unsupported device type %d for \"%s\"",
704                                   sa->sdl_type, name);
705         }
706 
707 	freeifaddrs(ifa);
708 }
709 #endif
710