xref: /illumos-gate/usr/src/cmd/cmd-inet/usr.sbin/snoop/snoop_capture.c (revision e11c3f44f531fdff80941ce57c065d2ae861cefc)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #include <stdio.h>
27 #include <string.h>
28 #include <errno.h>
29 #include <fcntl.h>
30 #include <setjmp.h>
31 #include <sys/types.h>
32 #include <sys/signal.h>
33 #include <sys/time.h>
34 #include <sys/socket.h>
35 #include <sys/sockio.h>
36 #include <net/if.h>
37 #include <netinet/in_systm.h>
38 #include <netinet/in.h>
39 #include <netinet/ip.h>
40 #include <sys/pfmod.h>
41 #include <netinet/if_ether.h>
42 #include <sys/mman.h>
43 #include <sys/stat.h>
44 #include <sys/stropts.h>
45 #include <sys/bufmod.h>
46 
47 #include <unistd.h>
48 #include <stropts.h>
49 #include <stdlib.h>
50 #include <ctype.h>
51 #include <values.h>
52 #include <libdlpi.h>
53 #include <sys/dlpi.h>
54 
55 #include "snoop.h"
56 
57 /*
58  * Old header format.
59  * Actually two concatenated structs:  nit_bufhdr + nit_head
60  */
61 struct ohdr {
62 	/* nit_bufhdr */
63 	int	o_msglen;
64 	int	o_totlen;
65 	/* nit_head */
66 	struct timeval o_time;
67 	int	o_drops;
68 	int	o_len;
69 };
70 
71 static void scan(char *, int, int, int, int, void (*)(), int, int, int);
72 void convert_to_network();
73 void convert_from_network();
74 static void convert_old(struct ohdr *);
75 extern sigjmp_buf jmp_env, ojmp_env;
76 static dlpi_info_t dlinfo;
77 static char *bufp;	/* pointer to read buffer */
78 
79 static int strioctl(int, int, int, int, void *);
80 
81 /*
82  * Open up the device in raw mode and passive mode
83  * (see dlpi_open(3DLPI)) and start finding out something about it,
84  * especially stuff about the data link headers. We need that information
85  * to build the proper packet filters.
86  */
87 boolean_t
88 check_device(dlpi_handle_t *dhp, char **devicep)
89 {
90 	int	retval;
91 	int	flags = DLPI_PASSIVE | DLPI_RAW;
92 
93 	/*
94 	 * Determine which network device
95 	 * to use if none given.
96 	 * Should get back a value like "le0".
97 	 */
98 	if (*devicep == NULL) {
99 		char *cbuf;
100 		static struct ifconf ifc;
101 		static struct ifreq *ifr;
102 		int s;
103 		int n;
104 		int numifs;
105 		unsigned bufsize;
106 
107 		if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
108 			pr_err("socket");
109 
110 		if (ioctl(s, SIOCGIFNUM, (char *)&numifs) < 0) {
111 			pr_err("check_device: ioctl SIOCGIFNUM");
112 			(void) close(s);
113 			s = -1;
114 			return (B_FALSE);
115 		}
116 
117 		bufsize = numifs * sizeof (struct ifreq);
118 		cbuf = (char *)malloc(bufsize);
119 		if (cbuf == NULL) {
120 			pr_err("out of memory\n");
121 			(void) close(s);
122 			s = -1;
123 			return (B_FALSE);
124 		}
125 		ifc.ifc_len = bufsize;
126 		ifc.ifc_buf = cbuf;
127 		if (ioctl(s, SIOCGIFCONF, (char *)&ifc) < 0) {
128 			pr_err("check_device: ioctl SIOCGIFCONF");
129 			(void) close(s);
130 			s = -1;
131 			(void) free(cbuf);
132 			return (B_FALSE);
133 		}
134 		n = ifc.ifc_len / sizeof (struct ifreq);
135 		ifr = ifc.ifc_req;
136 		for (; n > 0; n--, ifr++) {
137 			if (strchr(ifr->ifr_name, ':') != NULL)
138 				continue;
139 			if (ioctl(s, SIOCGIFFLAGS, (char *)ifr) < 0)
140 				pr_err("ioctl SIOCGIFFLAGS");
141 			if ((ifr->ifr_flags &
142 			    (IFF_VIRTUAL|IFF_IPMP|IFF_UP|
143 			    IFF_RUNNING)) == (IFF_UP|IFF_RUNNING))
144 				break;
145 		}
146 
147 		if (n == 0)
148 			pr_err("No network interface devices found");
149 
150 		*devicep = ifr->ifr_name;
151 		(void) close(s);
152 	}
153 	if (Iflg)
154 		flags |= DLPI_DEVIPNET;
155 	if (Iflg || strcmp(*devicep, "lo0") == 0)
156 		flags |= DLPI_IPNETINFO;
157 	if ((retval = dlpi_open(*devicep, dhp, flags)) != DLPI_SUCCESS) {
158 		pr_err("cannot open \"%s\": %s", *devicep,
159 		    dlpi_strerror(retval));
160 	}
161 
162 	if ((retval = dlpi_info(*dhp, &dlinfo, 0)) != DLPI_SUCCESS)
163 		pr_errdlpi(*dhp, "dlpi_info failed", retval);
164 
165 	for (interface = &INTERFACES[0]; interface->mac_type != -1; interface++)
166 		if (interface->mac_type == dlinfo.di_mactype)
167 			break;
168 
169 	/* allow limited functionality even if interface isn't known */
170 	if (interface->mac_type == -1) {
171 		(void) fprintf(stderr, "snoop: WARNING: Mac Type = %x "
172 		    "not supported\n", dlinfo.di_mactype);
173 	}
174 
175 	/* for backward compatibility, allow known interface mtu_sizes */
176 	if (interface->mtu_size > dlinfo.di_max_sdu)
177 		dlinfo.di_max_sdu = interface->mtu_size;
178 
179 	return (interface->try_kernel_filter);
180 }
181 
182 /*
183  * Do whatever is necessary to initialize the interface
184  * for packet capture. Bind the device opened in check_device(), set
185  * promiscuous mode, push the streams buffer module and packet filter
186  * module, set various buffer parameters.
187  */
188 void
189 initdevice(dlpi_handle_t dh, ulong_t snaplen, ulong_t chunksize,
190     struct timeval *timeout, struct Pf_ext_packetfilt *fp)
191 {
192 	int 	retv;
193 	int 	netfd;
194 	int	val = 1;
195 
196 	retv = dlpi_bind(dh, DLPI_ANY_SAP, NULL);
197 	if (retv != DLPI_SUCCESS)
198 		pr_errdlpi(dh, "cannot bind on", retv);
199 
200 	if (Iflg) {
201 		(void) fprintf(stderr, "Using device ipnet/%s ",
202 		    dlpi_linkname(dh));
203 	} else {
204 		(void) fprintf(stderr, "Using device %s ", dlpi_linkname(dh));
205 	}
206 
207 	/*
208 	 * If Pflg not set - use physical level
209 	 * promiscuous mode.  Otherwise - just SAP level.
210 	 */
211 	if (!Pflg) {
212 		(void) fprintf(stderr, "(promiscuous mode)\n");
213 		retv = dlpi_promiscon(dh, DL_PROMISC_PHYS);
214 		if (retv != DLPI_SUCCESS) {
215 			pr_errdlpi(dh, "promiscuous mode(physical) failed",
216 			    retv);
217 		}
218 	} else {
219 		(void) fprintf(stderr, "(non promiscuous)\n");
220 		retv = dlpi_promiscon(dh, DL_PROMISC_MULTI);
221 		if (retv != DLPI_SUCCESS) {
222 			pr_errdlpi(dh, "promiscuous mode(multicast) failed",
223 			    retv);
224 		}
225 	}
226 
227 	retv = dlpi_promiscon(dh, DL_PROMISC_SAP);
228 	if (retv != DLPI_SUCCESS)
229 		pr_errdlpi(dh, "promiscuous mode(SAP) failed", retv);
230 
231 	netfd = dlpi_fd(dh);
232 
233 	if (fp) {
234 		/*
235 		 * push and configure the packet filtering module
236 		 */
237 		if (ioctl(netfd, I_PUSH, "pfmod") < 0)
238 			pr_errdlpi(dh, "cannot push \"pfmod\"", DL_SYSERR);
239 
240 		if (strioctl(netfd, PFIOCSETF, -1, sizeof (*fp),
241 		    (char *)fp) < 0)
242 			pr_errdlpi(dh, "PFIOCSETF", DL_SYSERR);
243 	}
244 
245 	if (ioctl(netfd, I_PUSH, "bufmod") < 0)
246 		pr_errdlpi(dh, "cannot push \"bufmod\"", DL_SYSERR);
247 
248 	if (strioctl(netfd, SBIOCSTIME, -1, sizeof (struct timeval),
249 	    (char *)timeout) < 0)
250 		pr_errdlpi(dh, "SBIOCSTIME", DL_SYSERR);
251 
252 	if (strioctl(netfd, SBIOCSCHUNK, -1, sizeof (uint_t),
253 	    (char *)&chunksize) < 0)
254 		pr_errdlpi(dh, "SBIOCGCHUNK", DL_SYSERR);
255 
256 	if (strioctl(netfd, SBIOCSSNAP, -1, sizeof (uint_t),
257 	    (char *)&snaplen) < 0)
258 		pr_errdlpi(dh, "SBIOCSSNAP", DL_SYSERR);
259 
260 	/*
261 	 * Flush the read queue, to get rid of anything that
262 	 * accumulated before the device reached its final configuration.
263 	 */
264 	if (ioctl(netfd, I_FLUSH, FLUSHR) < 0)
265 		pr_errdlpi(dh, "cannot flush \"I_FLUSH\"", DL_SYSERR);
266 }
267 
268 /*
269  * Read packets from the network.  Initdevice is called in
270  * here to set up the network interface for reading of
271  * raw ethernet packets in promiscuous mode into a buffer.
272  * Packets are read and either written directly to a file
273  * or interpreted for display on the fly.
274  */
275 void
276 net_read(dlpi_handle_t dh, size_t chunksize, int filter, void (*proc)(),
277     int flags)
278 {
279 	int 	retval;
280 	extern int count;
281 	size_t	msglen;
282 
283 	count = 0;
284 
285 	/* allocate a read buffer */
286 	bufp = malloc(chunksize);
287 	if (bufp == NULL)
288 		pr_err("no memory for %d buffer", chunksize);
289 
290 	/*
291 	 * read frames
292 	 */
293 	for (;;) {
294 		msglen = chunksize;
295 		retval = dlpi_recv(dh, NULL, NULL, bufp, &msglen, -1, NULL);
296 
297 		if (retval != DLPI_SUCCESS || quitting)
298 			break;
299 
300 		if (msglen != 0)
301 			scan(bufp, msglen, filter, 0, 0, proc, 0, 0, flags);
302 	}
303 
304 	free(bufp);
305 
306 	if (!quitting)
307 		pr_errdlpi(dh, "network read failed", retval);
308 }
309 
310 #ifdef DEBUG
311 /*
312  * corrupt: simulate packet corruption for debugging interpreters
313  */
314 void
315 corrupt(volatile char *pktp, volatile char *pstop, char *buf,
316 	volatile char *bufstop)
317 {
318 	int c;
319 	int i;
320 	int p;
321 	int li = rand() % (pstop - pktp - 1) + 1;
322 	volatile char *pp = pktp;
323 	volatile char *pe = bufstop < pstop ? bufstop : pstop;
324 
325 	if (pktp < buf || pktp > bufstop)
326 		return;
327 
328 	for (pp = pktp; pp < pe; pp += li) {
329 		c = ((pe - pp) < li ? pe - pp : li);
330 		i = (rand() % c)>>1;
331 		while (--i > 0) {
332 			p = (rand() % c);
333 			pp[p] = (unsigned char)(rand() & 0xFF);
334 		}
335 	}
336 }
337 #endif /* DEBUG */
338 
339 static void
340 scan(char *buf, int len, int filter, int cap, int old, void (*proc)(),
341     int first, int last, int flags)
342 {
343 	volatile char *bp, *bufstop;
344 	volatile struct sb_hdr *hdrp;
345 	volatile struct sb_hdr nhdr, *nhdrp;
346 	volatile char *pktp;
347 	volatile struct timeval last_timestamp;
348 	volatile int header_okay;
349 	extern int count, maxcount;
350 	extern int snoop_nrecover;
351 #ifdef	DEBUG
352 	extern int zflg;
353 #endif	/* DEBUG */
354 
355 	proc(0, 0, 0);
356 	bufstop = buf + len;
357 
358 	/*
359 	 *
360 	 * Loop through each packet in the buffer
361 	 */
362 	last_timestamp.tv_sec = 0;
363 	(void) memcpy((char *)ojmp_env, (char *)jmp_env, sizeof (jmp_env));
364 	for (bp = buf; bp < bufstop; bp += nhdrp->sbh_totlen) {
365 		/*
366 		 * Gracefully exit if user terminates
367 		 */
368 		if (quitting)
369 			break;
370 		/*
371 		 * Global error recocery: Prepare to continue when a corrupt
372 		 * packet or header is encountered.
373 		 */
374 		if (sigsetjmp(jmp_env, 1)) {
375 			goto err;
376 		}
377 
378 		header_okay = 0;
379 		hdrp = (struct sb_hdr *)bp;
380 		nhdrp = hdrp;
381 		pktp = (char *)hdrp + sizeof (*hdrp);
382 
383 		/*
384 		 * If reading a capture file
385 		 * convert the headers from network
386 		 * byte order (for little-endians like X86)
387 		 */
388 		if (cap) {
389 			/*
390 			 * If the packets come from an old
391 			 * capture file, convert the header.
392 			 */
393 			if (old) {
394 				convert_old((struct ohdr *)hdrp);
395 			}
396 
397 			nhdrp = &nhdr;
398 
399 			nhdrp->sbh_origlen = ntohl(hdrp->sbh_origlen);
400 			nhdrp->sbh_msglen = ntohl(hdrp->sbh_msglen);
401 			nhdrp->sbh_totlen = ntohl(hdrp->sbh_totlen);
402 			nhdrp->sbh_drops = ntohl(hdrp->sbh_drops);
403 			nhdrp->sbh_timestamp.tv_sec =
404 			    ntohl(hdrp->sbh_timestamp.tv_sec);
405 			nhdrp->sbh_timestamp.tv_usec =
406 			    ntohl(hdrp->sbh_timestamp.tv_usec);
407 		}
408 
409 		/* Enhanced check for valid header */
410 
411 		if ((nhdrp->sbh_totlen == 0) ||
412 		    (bp + nhdrp->sbh_totlen) < bp ||
413 		    (bp + nhdrp->sbh_totlen) > bufstop ||
414 		    (nhdrp->sbh_origlen == 0) ||
415 		    (bp + nhdrp->sbh_origlen) < bp ||
416 		    (nhdrp->sbh_msglen == 0) ||
417 		    (bp + nhdrp->sbh_msglen) < bp ||
418 		    (bp + nhdrp->sbh_msglen) > bufstop ||
419 		    (nhdrp->sbh_msglen > nhdrp->sbh_origlen) ||
420 		    (nhdrp->sbh_totlen < nhdrp->sbh_msglen) ||
421 		    (nhdrp->sbh_timestamp.tv_sec == 0)) {
422 			if (cap) {
423 				(void) fprintf(stderr, "(warning) bad packet "
424 				    "header in capture file");
425 			} else {
426 				(void) fprintf(stderr, "(warning) bad packet "
427 				    "header in buffer");
428 			}
429 			(void) fprintf(stderr, " offset %d: length=%d\n",
430 			    bp - buf, nhdrp->sbh_totlen);
431 			goto err;
432 		}
433 
434 		if (nhdrp->sbh_totlen >
435 		    (dlinfo.di_max_sdu + MAX_HDRTRAILER)) {
436 			if (cap)
437 				(void) fprintf(stderr, "(warning) packet length"
438 				    " greater than MTU in capture file");
439 			else
440 				(void) fprintf(stderr, "(warning) packet length"
441 				    " greater than MTU in buffer");
442 
443 			(void) fprintf(stderr, " offset %d: length=%d\n",
444 			    bp - buf, nhdrp->sbh_totlen);
445 		}
446 
447 		/*
448 		 * Check for incomplete packet.  We are conservative here,
449 		 * since we don't know how good the checking is in other
450 		 * parts of the code.  We pass a partial packet, with
451 		 * a warning.
452 		 */
453 		if (pktp + nhdrp->sbh_msglen > bufstop) {
454 			(void) fprintf(stderr, "truncated packet buffer\n");
455 			nhdrp->sbh_msglen = bufstop - pktp;
456 		}
457 
458 #ifdef DEBUG
459 		if (zflg)
460 			corrupt(pktp, pktp + nhdrp->sbh_msglen, buf, bufstop);
461 #endif /* DEBUG */
462 
463 		header_okay = 1;
464 		if (!filter ||
465 		    want_packet(pktp,
466 		    nhdrp->sbh_msglen,
467 		    nhdrp->sbh_origlen)) {
468 			count++;
469 
470 			/*
471 			 * Start deadman timer for interpreter processing
472 			 */
473 			(void) snoop_alarm(SNOOP_ALARM_GRAN*SNOOP_MAXRECOVER,
474 			    NULL);
475 
476 			encap_levels = 0;
477 			if (!cap || count >= first)
478 				proc(nhdrp, pktp, count, flags);
479 
480 			if (cap && count >= last) {
481 				(void) snoop_alarm(0, NULL);
482 				break;
483 			}
484 
485 			if (maxcount && count >= maxcount) {
486 				(void) fprintf(stderr, "%d packets captured\n",
487 				    count);
488 				exit(0);
489 			}
490 
491 			snoop_nrecover = 0;			/* success */
492 			(void) snoop_alarm(0, NULL);
493 			last_timestamp = hdrp->sbh_timestamp;	/* save stamp */
494 		}
495 		continue;
496 err:
497 		/*
498 		 * Corruption has been detected. Reset errors.
499 		 */
500 		snoop_recover();
501 
502 		/*
503 		 * packet header was apparently okay. Continue.
504 		 */
505 		if (header_okay)
506 			continue;
507 
508 		/*
509 		 * Otherwise try to scan forward to the next packet, using
510 		 * the last known timestamp if it is available.
511 		 */
512 		nhdrp = &nhdr;
513 		nhdrp->sbh_totlen = 0;
514 		if (last_timestamp.tv_sec == 0) {
515 			bp += sizeof (int);
516 		} else {
517 			for (bp += sizeof (int); bp <= bufstop;
518 			    bp += sizeof (int)) {
519 				hdrp = (struct sb_hdr *)bp;
520 				/* An approximate timestamp located */
521 				if ((hdrp->sbh_timestamp.tv_sec >> 8) ==
522 				    (last_timestamp.tv_sec >> 8))
523 					break;
524 			}
525 		}
526 	}
527 	/* reset jmp_env for program exit */
528 	(void) memcpy((char *)jmp_env, (char *)ojmp_env, sizeof (jmp_env));
529 	proc(0, -1, 0);
530 }
531 
532 /*
533  * Called if nwrite() encounters write problems.
534  */
535 static void
536 cap_write_error(const char *msgtype)
537 {
538 	(void) fprintf(stderr,
539 	    "snoop: cannot write %s to capture file: %s\n",
540 	    msgtype, strerror(errno));
541 	exit(1);
542 }
543 
544 /*
545  * Writes target buffer to the open file descriptor. Upon detection of a short
546  * write, an attempt to process the remaining bytes occurs until all anticipated
547  * bytes are written. An error status is returned to indicate any serious write
548  * failures.
549  */
550 static int
551 nwrite(int fd, const void *buffer, size_t buflen)
552 {
553 	size_t nwritten;
554 	ssize_t nbytes = 0;
555 	const char *buf = buffer;
556 
557 	for (nwritten = 0; nwritten < buflen; nwritten += nbytes) {
558 		nbytes = write(fd, &buf[nwritten], buflen - nwritten);
559 		if (nbytes == -1)
560 			return (-1);
561 		if (nbytes == 0) {
562 			errno = EIO;
563 			return (-1);
564 		}
565 	}
566 	return (0);
567 }
568 
569 /*
570  * Routines for opening, closing, reading and writing
571  * a capture file of packets saved with the -o option.
572  */
573 static int capfile_out;
574 
575 /*
576  * The snoop capture file has a header to identify
577  * it as a capture file and record its version.
578  * A file without this header is assumed to be an
579  * old format snoop file.
580  *
581  * A version 1 header looks like this:
582  *
583  *   0   1   2   3   4   5   6   7   8   9  10  11
584  * +---+---+---+---+---+---+---+---+---+---+---+---+---+
585  * | s | n | o | o | p | \0| \0| \0|    version    |  data
586  * +---+---+---+---+---+---+---+---+---+---+---+---+---+
587  * |	 word 0	   |	 word 1	   |	 word 2	   |
588  *
589  *
590  * A version 2 header adds a word that identifies the MAC type.
591  * This allows for capture files from FDDI etc.
592  *
593  *   0   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15
594  * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
595  * | s | n | o | o | p | \0| \0| \0|    version    |    MAC type   | data
596  * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
597  * |	 word 0	   |	 word 1	   |	 word 2	   |	 word 3
598  *
599  */
600 static const char *snoop_id = "snoop\0\0\0";
601 static const int snoop_idlen = 8;
602 static const int snoop_version = 2;
603 
604 void
605 cap_open_write(const char *name)
606 {
607 	int vers;
608 
609 	capfile_out = open(name, O_CREAT | O_TRUNC | O_RDWR, 0666);
610 	if (capfile_out < 0)
611 		pr_err("%s: %m", name);
612 
613 	vers = htonl(snoop_version);
614 	if (nwrite(capfile_out, snoop_id, snoop_idlen) == -1)
615 		cap_write_error("snoop_id");
616 
617 	if (nwrite(capfile_out, &vers, sizeof (int)) == -1)
618 		cap_write_error("version");
619 }
620 
621 
622 void
623 cap_close(void)
624 {
625 	(void) close(capfile_out);
626 }
627 
628 static char *cap_buffp = NULL;
629 static int cap_len = 0;
630 static int cap_new;
631 
632 void
633 cap_open_read(const char *name)
634 {
635 	struct stat st;
636 	int cap_vers;
637 	int *word, device_mac_type;
638 	int capfile_in;
639 
640 	capfile_in = open(name, O_RDONLY);
641 	if (capfile_in < 0)
642 		pr_err("couldn't open %s: %m", name);
643 
644 	if (fstat(capfile_in, &st) < 0)
645 		pr_err("couldn't stat %s: %m", name);
646 	cap_len = st.st_size;
647 
648 	cap_buffp = mmap(0, cap_len, PROT_READ, MAP_PRIVATE, capfile_in, 0);
649 	(void) close(capfile_in);
650 	if ((int)cap_buffp == -1)
651 		pr_err("couldn't mmap %s: %m", name);
652 
653 	/* Check if new snoop capture file format */
654 
655 	cap_new = bcmp(cap_buffp, snoop_id, snoop_idlen) == 0;
656 
657 	/*
658 	 * If new file - check version and
659 	 * set buffer pointer to point at first packet
660 	 */
661 	if (cap_new) {
662 		cap_vers = ntohl(*(int *)(cap_buffp + snoop_idlen));
663 		cap_buffp += snoop_idlen + sizeof (int);
664 		cap_len   -= snoop_idlen + sizeof (int);
665 
666 		switch (cap_vers) {
667 		case 1:
668 			device_mac_type = DL_ETHER;
669 			break;
670 
671 		case 2:
672 			device_mac_type = ntohl(*((int *)cap_buffp));
673 			cap_buffp += sizeof (int);
674 			cap_len   -= sizeof (int);
675 			break;
676 
677 		default:
678 			pr_err("capture file: %s: Version %d unrecognized\n",
679 			    name, cap_vers);
680 		}
681 
682 		for (interface = &INTERFACES[0]; interface->mac_type != -1;
683 		    interface++)
684 			if (interface->mac_type == device_mac_type)
685 				break;
686 
687 		if (interface->mac_type == -1)
688 			pr_err("Mac Type = %x is not supported\n",
689 			    device_mac_type);
690 	} else {
691 		/* Use heuristic to check if it's an old-style file */
692 
693 		device_mac_type = DL_ETHER;
694 		word = (int *)cap_buffp;
695 
696 		if (!((word[0] < 1600 && word[1] < 1600) &&
697 		    (word[0] < word[1]) &&
698 		    (word[2] > 610000000 && word[2] < 770000000)))
699 			pr_err("not a capture file: %s", name);
700 
701 		/* Change protection so's we can fix the headers */
702 
703 		if (mprotect(cap_buffp, cap_len, PROT_READ | PROT_WRITE) < 0)
704 			pr_err("mprotect: %s: %m", name);
705 	}
706 	dlinfo.di_max_sdu = MAXINT;	/* Decode any stored packet. */
707 }
708 
709 void
710 cap_read(int first, int last, int filter, void (*proc)(), int flags)
711 {
712 	extern int count;
713 
714 	count = 0;
715 
716 	scan(cap_buffp, cap_len, filter, 1, !cap_new, proc, first, last, flags);
717 
718 	(void) munmap(cap_buffp, cap_len);
719 }
720 
721 /* ARGSUSED */
722 void
723 cap_write(struct sb_hdr *hdrp, char *pktp, int num, int flags)
724 {
725 	int pktlen, mac;
726 	static int first = 1;
727 	struct sb_hdr nhdr;
728 	extern boolean_t qflg;
729 
730 	if (hdrp == NULL)
731 		return;
732 
733 	if (first) {
734 		first = 0;
735 		mac = htonl(interface->mac_type);
736 		if (nwrite(capfile_out, &mac, sizeof (int)) == -1)
737 			cap_write_error("mac_type");
738 	}
739 
740 	pktlen = hdrp->sbh_totlen - sizeof (*hdrp);
741 
742 	/*
743 	 * Convert sb_hdr to network byte order
744 	 */
745 	nhdr.sbh_origlen = htonl(hdrp->sbh_origlen);
746 	nhdr.sbh_msglen = htonl(hdrp->sbh_msglen);
747 	nhdr.sbh_totlen = htonl(hdrp->sbh_totlen);
748 	nhdr.sbh_drops = htonl(hdrp->sbh_drops);
749 	nhdr.sbh_timestamp.tv_sec = htonl(hdrp->sbh_timestamp.tv_sec);
750 	nhdr.sbh_timestamp.tv_usec = htonl(hdrp->sbh_timestamp.tv_usec);
751 
752 	if (nwrite(capfile_out, &nhdr, sizeof (nhdr)) == -1)
753 		cap_write_error("packet header");
754 
755 	if (nwrite(capfile_out, pktp, pktlen) == -1)
756 		cap_write_error("packet");
757 
758 	if (! qflg)
759 		show_count();
760 }
761 
762 /*
763  * Convert a packet header from
764  * old to new format.
765  */
766 static void
767 convert_old(struct ohdr *ohdrp)
768 {
769 	struct sb_hdr nhdr;
770 
771 	nhdr.sbh_origlen = ohdrp->o_len;
772 	nhdr.sbh_msglen  = ohdrp->o_msglen;
773 	nhdr.sbh_totlen  = ohdrp->o_totlen;
774 	nhdr.sbh_drops   = ohdrp->o_drops;
775 	nhdr.sbh_timestamp = ohdrp->o_time;
776 
777 	*(struct sb_hdr *)ohdrp = nhdr;
778 }
779 
780 static int
781 strioctl(int fd, int cmd, int timout, int len, void *dp)
782 {
783 	struct	strioctl	sioc;
784 	int	rc;
785 
786 	sioc.ic_cmd = cmd;
787 	sioc.ic_timout = timout;
788 	sioc.ic_len = len;
789 	sioc.ic_dp = dp;
790 	rc = ioctl(fd, I_STR, &sioc);
791 
792 	if (rc < 0)
793 		return (rc);
794 	else
795 		return (sioc.ic_len);
796 }
797