3 * $Id: libpcap.c,v 1.56 2001/11/09 07:44:51 guy Exp $
6 * Copyright (c) 1998 by Gilbert Ramirez <gram@xiexie.org>
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version 2
11 * of the License, or (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 #include "file_wrappers.h"
33 /* See source to the "libpcap" library for information on the "libpcap"
36 /* On some systems, the FDDI MAC addresses are bit-swapped. */
37 #if !defined(ultrix) && !defined(__alpha) && !defined(__bsdi__)
38 #define BIT_SWAPPED_MAC_ADDRS
42 /* Try to read the first two records of the capture file. */
44 THIS_FORMAT, /* the reads succeeded, assume it's this format */
45 BAD_READ, /* the file is probably not valid */
46 OTHER_FORMAT /* the file may be valid, but not in this format */
48 static libpcap_try_t libpcap_try(wtap *wth, int *err);
50 static gboolean libpcap_read(wtap *wth, int *err, long *data_offset);
51 static int libpcap_read_header(wtap *wth, int *err,
52 struct pcaprec_ss990915_hdr *hdr, gboolean silent);
53 static void adjust_header(wtap *wth, struct pcaprec_hdr *hdr);
54 static void libpcap_close(wtap *wth);
55 static gboolean libpcap_dump(wtap_dumper *wdh, const struct wtap_pkthdr *phdr,
56 const union wtap_pseudo_header *pseudo_header, const u_char *pd, int *err);
59 * Either LBL NRG wasn't an adequate central registry (e.g., because of
60 * the slow rate of releases from them), or nobody bothered using them
61 * as a central registry, as many different groups have patched libpcap
62 * (and BPF, on the BSDs) to add new encapsulation types, and have ended
63 * up using the same DLT_ values for different encapsulation types.
65 * For those numerical encapsulation type values that everybody uses for
66 * the same encapsulation type (which inclues those that some platforms
67 * specify different DLT_ names for but don't appear to use), we map
68 * those values to the appropriate Wiretap values.
70 * For those numerical encapsulation type values that different libpcap
71 * variants use for different encapsulation types, we check what
72 * <pcap.h> defined to determine how to interpret them, so that we
73 * interpret them the way the libpcap with which we're building
74 * Ethereal/Wiretap interprets them (which, if it doesn't support
75 * them at all, means we don't support them either - any capture files
76 * using them are foreign, and we don't hazard a guess as to which
77 * platform they came from; we could, I guess, choose the most likely
88 } pcap_to_wtap_map[] = {
90 * These are the values that are almost certainly the same
91 * in all libpcaps (I've yet to find one where the values
92 * in question are used for some purpose other than the
93 * one below, but...), and that Wiretap and Ethereal
96 { 0, WTAP_ENCAP_NULL }, /* null encapsulation */
97 { 1, WTAP_ENCAP_ETHERNET },
98 { 6, WTAP_ENCAP_TOKEN_RING }, /* IEEE 802 Networks - assume token ring */
99 { 7, WTAP_ENCAP_ARCNET },
100 { 8, WTAP_ENCAP_SLIP },
101 { 9, WTAP_ENCAP_PPP },
102 #ifdef BIT_SWAPPED_MAC_ADDRS
103 { 10, WTAP_ENCAP_FDDI_BITSWAPPED },
105 { 10, WTAP_ENCAP_FDDI },
109 * 11 is DLT_ATM_RFC1483 on most platforms; the only libpcaps I've
110 * seen that define anything other than DLT_ATM_RFC1483 as 11 are
111 * the BSD/OS one, which defines DLT_FR as 11, and libpcap 0.5,
112 * which define it as 100, mapping the kernel's value to 100, in
113 * an attempt to hide the different values used on different
116 * If this is a platform where DLT_FR is defined as 11, we
117 * don't handle 11 at all; otherwise, we handle it as
118 * DLT_ATM_RFC1483 (this means we'd misinterpret Frame Relay
119 * captures from BSD/OS if running on platforms other than BSD/OS,
122 * 1) we don't yet support DLT_FR
126 * 2) nothing short of a heuristic would let us interpret
129 #if defined(DLT_FR) && (DLT_FR == 11)
130 /* Put entry for Frame Relay here */
132 { 11, WTAP_ENCAP_ATM_RFC1483 },
136 * 12 is DLT_RAW on most platforms, but it's DLT_C_HDLC on
137 * BSD/OS, and DLT_LOOP on OpenBSD.
139 * We don't yet handle DLT_C_HDLC, but we can handle DLT_LOOP
140 * (it's just like DLT_NULL, only with the AF_ value in network
141 * rather than host byte order - Ethereal figures out the
142 * byte order from the data, so we don't care what byte order
143 * it's in), so if DLT_LOOP is defined as 12, interpret 12
144 * as WTAP_ENCAP_NULL, otherwise, unless DLT_C_HDLC is defined
145 * as 12, interpret it as WTAP_ENCAP_RAW_IP.
147 #if defined(DLT_LOOP) && (DLT_LOOP == 12)
148 { 12, WTAP_ENCAP_NULL },
149 #elif defined(DLT_C_HDLC) && (DLT_C_HDLC == 12)
151 * Put entry for Cisco HDLC here.
152 * XXX - is this just WTAP_ENCAP_CHDLC, i.e. does the frame
153 * start with a 4-byte Cisco HDLC header?
156 { 12, WTAP_ENCAP_RAW_IP },
160 * 13 is DLT_SLIP_BSDOS on FreeBSD and NetBSD, but those OSes
161 * don't actually generate it. I infer that BSD/OS translates
162 * DLT_SLIP from the kernel BPF code to DLT_SLIP_BSDOS in
163 * libpcap, as the BSD/OS link-layer header is different;
164 * however, in BSD/OS, DLT_SLIP_BSDOS is 15.
166 * From this, I infer that there's no point in handling 13
169 * 13 is DLT_ATM_RFC1483 on BSD/OS.
171 * 13 is DLT_ENC in OpenBSD, which is, I suspect, some kind
172 * of decrypted IPSEC traffic.
174 #if defined(DLT_ATM_RFC1483) && (DLT_ATM_RFC1483 == 13)
175 { 13, WTAP_ENCAP_ATM_RFC1483 },
176 #elif defined(DLT_ENC) && (DLT_ENC == 13)
177 /* Put entry for DLT_ENC here */
181 * 14 is DLT_PPP_BSDOS on FreeBSD and NetBSD, but those OSes
182 * don't actually generate it. I infer that BSD/OS translates
183 * DLT_PPP from the kernel BPF code to DLT_PPP_BSDOS in
184 * libpcap, as the BSD/OS link-layer header is different;
185 * however, in BSD/OS, DLT_PPP_BSDOS is 16.
187 * From this, I infer that there's no point in handling 14
190 * 14 is DLT_RAW on BSD/OS and OpenBSD.
192 { 14, WTAP_ENCAP_RAW_IP },
197 * DLT_SLIP_BSDOS on BSD/OS;
199 * DLT_HIPPI on NetBSD;
201 * DLT_LANE8023 with Alexey Kuznetzov's patches for
204 * DLT_I4L_RAWIP with the ISDN4Linux patches for libpcap
207 * but we don't currently handle any of those.
213 * DLT_PPP_BSDOS on BSD/OS;
215 * DLT_HDLC on NetBSD (Cisco HDLC);
217 * DLT_CIP with Alexey Kuznetzov's patches for
218 * Linux libpcap - this is WTAP_ENCAP_LINUX_ATM_CLIP;
220 * DLT_I4L_IP with the ISDN4Linux patches for libpcap
223 #if defined(DLT_CIP) && (DLT_CIP == 16)
224 { 16, WTAP_ENCAP_LINUX_ATM_CLIP },
226 #if defined(DLT_HDLC) && (DLT_HDLC == 16)
227 { 16, WTAP_ENCAP_CHDLC },
231 * 17 is DLT_LANE8023 in SuSE 6.3 libpcap; we don't currently
236 * 18 is DLT_CIP in SuSE 6.3 libpcap; if it's the same as the
237 * DLT_CIP of 16 that the Alexey Kuznetzov patches for
238 * libpcap/tcpdump define, it's WTAP_ENCAP_LINUX_ATM_CLIP.
239 * I've not found any libpcap that uses it for any other purpose -
240 * hopefully nobody will do so in the future.
242 { 18, WTAP_ENCAP_LINUX_ATM_CLIP },
245 * 19 is DLT_ATM_CLIP in the libpcap/tcpdump patches in the
246 * recent versions I've seen of the Linux ATM distribution;
247 * I've not yet found any libpcap that uses it for any other
248 * purpose - hopefully nobody will do so in the future.
250 { 19, WTAP_ENCAP_LINUX_ATM_CLIP },
253 * 50 is DLT_PPP_SERIAL in NetBSD; it appears that DLT_PPP
254 * on BSD (at least according to standard tcpdump) has, as
255 * the first octet, an indication of whether the packet was
256 * transmitted or received (rather than having the standard
257 * PPP address value of 0xff), but that DLT_PPP_SERIAL puts
258 * a real live PPP header there, or perhaps a Cisco PPP header
259 * as per section 4.3.1 of RFC 1547 (implementations of this
260 * exist in various BSDs in "sys/net/if_spppsubr.c", and
261 * I think also exist either in standard Linux or in
262 * various Linux patches; the implementations show how to handle
263 * Cisco keepalive packets).
265 * However, I don't see any obvious place in FreeBSD "if_ppp.c"
266 * where anything other than the standard PPP header would be
267 * passed up. I see some stuff that sets the first octet
268 * to 0 for incoming and 1 for outgoing packets before applying
269 * a BPF filter to see whether to drop packets whose protocol
270 * field has the 0x8000 bit set, i.e. network control protocols -
271 * those are handed up to userland - but that code puts the
272 * address field back before passing the packet up.
274 * I also don't see anything immediately obvious that munges
275 * the address field for sync PPP, either.
277 * Ethereal currently assumes that if the first octet of a
278 * PPP frame is 0xFF, it's the address field and is followed
279 * by a control field and a 2-byte protocol, otherwise the
280 * address and control fields are absent and the frame begins
281 * with a protocol field. If we ever see a BSD/OS PPP
282 * capture, we'll have to handle it differently, and we may
283 * have to handle standard BSD captures differently if, in fact,
284 * they don't have 0xff 0x03 as the first two bytes - but, as per
285 * the two paragraphs preceding this, it's not clear that
286 * the address field *is* munged into an incoming/outgoing
287 * field when the packet is handed to the BPF device.
289 * For now, we just map DLT_PPP_SERIAL to WTAP_ENCAP_PPP, as
290 * we treat WTAP_ENCAP_PPP packets as if those beginning with
291 * 0xff have the standard RFC 1662 "PPP in HDLC-like Framing"
292 * 0xff 0x03 address/control header, and DLT_PPP_SERIAL frames
293 * appear to contain that unless they're Cisco frames (if we
294 * ever see a capture with them, we'd need to implement the
295 * RFC 1547 stuff, and the keepalive protocol stuff).
297 * We may have to distinguish between "PPP where if it doesn't
298 * begin with 0xff there's no HDLC encapsulation and the frame
299 * begins with the protocol field" (which is how we handle
300 * WTAP_ENCAP_PPP now) and "PPP where there's either HDLC
301 * encapsulation or Cisco PPP" (which is what DLT_PPP_SERIAL
304 * XXX - NetBSD has DLT_HDLC, which appears to be used for
305 * Cisco HDLC. Ideally, they should use DLT_PPP_SERIAL
306 * only for real live HDLC-encapsulated PPP, not for Cisco
309 { 50, WTAP_ENCAP_PPP },
312 * These are the values that libpcap 0.5 uses, in an attempt
313 * to work around the confusion decried above, and that Wiretap
314 * and Ethereal currently support.
316 * The next version of libpcap will probably not use them as
317 * DLT_ values in its API, but will probably use them in capture
320 { 100, WTAP_ENCAP_ATM_RFC1483 },
321 { 101, WTAP_ENCAP_RAW_IP },
324 * More values used by libpcap 0.5 as DLT_ values and used by the
325 * current CVS version of libpcap in capture file headers.
326 * They are not yet handled in Ethereal.
327 * If we get a capture that contains them, we'll implement them.
329 { 102, WTAP_ENCAP_SLIP_BSDOS },
330 { 103, WTAP_ENCAP_PPP_BSDOS },
334 * These ones are handled in Ethereal, though.
336 { 104, WTAP_ENCAP_CHDLC }, /* Cisco HDLC */
337 { 106, WTAP_ENCAP_LINUX_ATM_CLIP },
340 * Values not yet used by the current CVS version of libpcap,
341 * but reserved for future use; the IEEE 802.11 value is
342 * there for use with a capture program from Axis Communications.
344 { 105, WTAP_ENCAP_IEEE_802_11 },
347 * Not yet handled in Ethereal; we don't know what encapsulation
348 * BSD/OS uses, so we don't know whether it can be handed to
349 * the Frame Relay dissector or not.
351 { 107, WTAP_ENCAP_FR }, /* Frame Relay */
353 { 108, WTAP_ENCAP_NULL }, /* OpenBSD loopback */
355 { 109, WTAP_ENCAP_ENC }, /* OpenBSD IPSEC enc */
356 { 110, WTAP_ENCAP_LANE_802_3 },/* ATM LANE 802.3 */
357 { 111, WTAP_ENCAP_HIPPI }, /* NetBSD HIPPI */
359 { 112, WTAP_ENCAP_CHDLC }, /* NetBSD HDLC framing */
362 * Linux "cooked mode" captures, used by the current CVS version
365 { 113, WTAP_ENCAP_SLL }, /* Linux cooked capture */
367 { 118, WTAP_ENCAP_CISCO_IOS },
369 #define NUM_PCAP_ENCAPS (sizeof pcap_to_wtap_map / sizeof pcap_to_wtap_map[0])
371 int libpcap_open(wtap *wth, int *err)
376 gboolean byte_swapped;
381 /* Read in the number that should be at the start of a "libpcap" file */
382 errno = WTAP_ERR_CANT_READ;
383 bytes_read = file_read(&magic, 1, sizeof magic, wth->fh);
384 if (bytes_read != sizeof magic) {
385 *err = file_error(wth->fh);
390 wth->data_offset += sizeof magic;
395 /* Host that wrote it has our byte order, and was running
396 a program using either standard or ss990417 libpcap. */
397 byte_swapped = FALSE;
401 case PCAP_MODIFIED_MAGIC:
402 /* Host that wrote it has our byte order, and was running
403 a program using either ss990915 or ss991029 libpcap. */
404 byte_swapped = FALSE;
408 case PCAP_SWAPPED_MAGIC:
409 /* Host that wrote it has a byte order opposite to ours,
410 and was running a program using either standard or
416 case PCAP_SWAPPED_MODIFIED_MAGIC:
417 /* Host that wrote it out has a byte order opposite to
418 ours, and was running a program using either ss990915
419 or ss991029 libpcap. */
425 /* Not a "libpcap" type we know about. */
429 /* Read the rest of the header. */
430 errno = WTAP_ERR_CANT_READ;
431 bytes_read = file_read(&hdr, 1, sizeof hdr, wth->fh);
432 if (bytes_read != sizeof hdr) {
433 *err = file_error(wth->fh);
438 wth->data_offset += sizeof hdr;
441 /* Byte-swap the header fields about which we care. */
442 hdr.version_major = BSWAP16(hdr.version_major);
443 hdr.version_minor = BSWAP16(hdr.version_minor);
444 hdr.snaplen = BSWAP32(hdr.snaplen);
445 hdr.network = BSWAP32(hdr.network);
447 if (hdr.version_major < 2) {
448 /* We only support version 2.0 and later. */
449 g_message("pcap: major version %u unsupported",
451 *err = WTAP_ERR_UNSUPPORTED;
456 * AIX's non-standard tcpdump uses a minor version number of 2.
457 * Unfortunately, older versions of libpcap might have used
460 * The AIX libpcap uses RFC 1573 ifType values rather than
461 * DLT_ values in the header; the ifType values for LAN devices
468 * which correspond to DLT_IEEE802 (used for Token Ring),
469 * DLT_PPP, and DLT_SLIP_BSDOS, respectively. We shall
470 * assume that if the minor version number is 2, and
471 * the network type is 6, 9, or 15, that it's AIX libpcap;
473 * I'm assuming those older versions of libpcap didn't
474 * use DLT_IEEE802 for Token Ring, and didn't use DLT_SLIP_BSDOS
475 * as that came later. It may have used DLT_SLIP, however, in
476 * which case we're out of luck; we assume it's Token Ring
477 * in AIX libpcap rather than PPP in standard libpcap, as
478 * you're probably more likely to be handing an AIX libpcap
479 * token-ring capture than an old (pre-libpcap 0.4) PPP capture
482 aix = FALSE; /* assume it's not AIX */
483 if (hdr.version_major == 2 && hdr.version_minor == 2) {
484 switch (hdr.network) {
487 hdr.network = 1; /* DLT_EN10MB, Ethernet */
492 hdr.network = 6; /* DLT_IEEE802, Token Ring */
497 hdr.network = 10; /* DLT_FDDI, FDDI */
502 file_encap = wtap_pcap_encap_to_wtap_encap(hdr.network);
503 if (file_encap == WTAP_ENCAP_UNKNOWN) {
504 g_message("pcap: network type %u unknown or unsupported",
506 *err = WTAP_ERR_UNSUPPORTED_ENCAP;
510 /* This is a libpcap file */
511 wth->capture.pcap = g_malloc(sizeof(libpcap_t));
512 wth->capture.pcap->byte_swapped = byte_swapped;
513 wth->capture.pcap->version_major = hdr.version_major;
514 wth->capture.pcap->version_minor = hdr.version_minor;
515 wth->subtype_read = libpcap_read;
516 wth->subtype_seek_read = wtap_def_seek_read;
517 wth->subtype_close = libpcap_close;
518 wth->file_encap = file_encap;
519 wth->snapshot_length = hdr.snaplen;
522 * Is this AIX format?
526 * Yes. Skip all the tests for other mutant formats.
528 wth->file_type = WTAP_FILE_PCAP_AIX;
533 * No. Let's look at the header for the first record,
534 * and see if, interpreting it as a standard header (if the
535 * magic number was standard) or a modified header (if the
536 * magic number was modified), the position where it says the
537 * header for the *second* record is contains a corrupted header.
541 * If this file had the standard magic number, it may be
542 * an ss990417 capture file - in that version of Alexey's
543 * patch, the packet header format was changed but the
544 * magic number wasn't, and, alas, Red Hat appear to have
545 * picked up that version of the patch for RH 6.1, meaning
546 * RH 6.1 has a tcpdump that writes out files that can't
547 * be read by any software that expects non-modified headers
548 * if the magic number isn't the modified magic number (e.g.,
549 * any normal version of tcpdump, and Ethereal if we don't
550 * do this gross heuristic).
552 * If this file had the modified magic number, it may be
553 * an ss990915 capture file - in that version of Alexey's
554 * patch, the magic number was changed, but the record
555 * header had some extra fields, and, alas, SuSE appear
556 * to have picked up that version of the patch for SuSE
557 * 6.3, meaning that programs expecting the standard per-
558 * packet header in captures with the modified magic number
559 * can't read dumps from its tcpdump.
561 * Oh, and if it has the standard magic number, it might, instead,
562 * be a Nokia libpcap file, so we may need to try that if
563 * neither normal nor ss990417 headers work.
567 * Well, we have the magic number from Alexey's
570 * Try ss991029, the last of his patches, first.
572 wth->file_type = WTAP_FILE_PCAP_SS991029;
573 switch (libpcap_try(wth, err)) {
577 * Well, we couldn't even read it.
584 * Well, it looks as if it might be 991029.
585 * Put the seek pointer back, and return success.
587 file_seek(wth->fh, wth->data_offset, SEEK_SET);
592 * Try the next format.
598 * Well, it's not completely unreadable,
599 * but it's not ss991029. Try ss990915;
600 * there are no other types to try after that,
601 * so we put the seek pointer back and treat
604 wth->file_type = WTAP_FILE_PCAP_SS990915;
605 file_seek(wth->fh, wth->data_offset, SEEK_SET);
608 * Well, we have the standard magic number.
610 * Try the standard format first.
612 wth->file_type = WTAP_FILE_PCAP;
613 switch (libpcap_try(wth, err)) {
617 * Well, we couldn't even read it.
624 * Well, it looks as if it might be a standard
626 * Put the seek pointer back, and return success.
628 file_seek(wth->fh, wth->data_offset, SEEK_SET);
633 * Try the next format.
639 * Well, it's not completely unreadable, but it's not
640 * a standard file. Put the seek pointer back and try
643 wth->file_type = WTAP_FILE_PCAP_SS990417;
644 file_seek(wth->fh, wth->data_offset, SEEK_SET);
645 switch (libpcap_try(wth, err)) {
649 * Well, we couldn't even read it.
656 * Well, it looks as if it might be ss990417.
657 * Put the seek pointer back, and return success.
659 file_seek(wth->fh, wth->data_offset, SEEK_SET);
664 * Try the next format.
670 * Well, it's not completely unreadable,
671 * but it's not a standard file *nor* is it ss990417.
672 * Try it as a Nokia file; there are no other types
673 * to try after that, so we put the seek pointer back
674 * and treat it as a Nokia file.
676 wth->file_type = WTAP_FILE_PCAP_NOKIA;
677 file_seek(wth->fh, wth->data_offset, SEEK_SET);
683 /* Try to read the first two records of the capture file. */
684 static libpcap_try_t libpcap_try(wtap *wth, int *err)
687 * pcaprec_ss990915_hdr is the largest header type.
689 struct pcaprec_ss990915_hdr first_rec_hdr, second_rec_hdr;
692 * Attempt to read the first record's header.
694 if (libpcap_read_header(wth, err, &first_rec_hdr, TRUE) == -1) {
695 if (*err == 0 || *err == WTAP_ERR_SHORT_READ) {
697 * EOF or short read - assume the file is in this
699 * When our client tries to read the first packet
700 * they will presumably get the same EOF or short
706 if (*err == WTAP_ERR_BAD_RECORD) {
708 * The first record is bogus, so this is probably
709 * a corrupt file. Assume the file is in this
710 * format. When our client tries to read the
711 * first packet they will presumably get the
718 * Some other error, e.g. an I/O error; just give up.
724 * Now skip over the first record's data, under the assumption
725 * that the header is sane.
727 file_seek(wth->fh, first_rec_hdr.hdr.incl_len, SEEK_CUR);
730 * Now attempt to read the second record's header.
732 if (libpcap_read_header(wth, err, &second_rec_hdr, TRUE) == -1) {
733 if (*err == 0 || *err == WTAP_ERR_SHORT_READ) {
735 * EOF or short read - assume the file is in this
737 * When our client tries to read the second packet
738 * they will presumably get the same EOF or short
744 if (*err == WTAP_ERR_BAD_RECORD) {
746 * The second record is bogus; maybe it's a
747 * Capture File From Hell, and what looks like
748 * the "header" of the next packet is actually
749 * random junk from the middle of a packet.
750 * Try the next format; if we run out of formats,
751 * it probably *is* a corrupt file.
757 * Some other error, e.g. an I/O error; just give up.
763 * OK, the first two records look OK; assume this is the
769 /* Read the next packet */
770 static gboolean libpcap_read(wtap *wth, int *err, long *data_offset)
772 struct pcaprec_ss990915_hdr hdr;
776 bytes_read = libpcap_read_header(wth, err, &hdr, FALSE);
777 if (bytes_read == -1) {
779 * We failed to read the header.
784 wth->data_offset += bytes_read;
785 packet_size = hdr.hdr.incl_len;
787 buffer_assure_space(wth->frame_buffer, packet_size);
788 *data_offset = wth->data_offset;
789 errno = WTAP_ERR_CANT_READ;
790 bytes_read = file_read(buffer_start_ptr(wth->frame_buffer), 1,
791 packet_size, wth->fh);
793 if ((guint)bytes_read != packet_size) {
794 *err = file_error(wth->fh);
796 *err = WTAP_ERR_SHORT_READ;
799 wth->data_offset += packet_size;
801 wth->phdr.ts.tv_sec = hdr.hdr.ts_sec;
802 wth->phdr.ts.tv_usec = hdr.hdr.ts_usec;
803 wth->phdr.caplen = packet_size;
804 wth->phdr.len = hdr.hdr.orig_len;
805 wth->phdr.pkt_encap = wth->file_encap;
810 /* Read the header of the next packet; if "silent" is TRUE, don't complain
811 to the console, as we're testing to see if the file appears to be of a
814 Return -1 on an error, or the number of bytes of header read on success. */
815 static int libpcap_read_header(wtap *wth, int *err,
816 struct pcaprec_ss990915_hdr *hdr, gboolean silent)
818 int bytes_to_read, bytes_read;
820 /* Read record header. */
821 errno = WTAP_ERR_CANT_READ;
822 switch (wth->file_type) {
825 case WTAP_FILE_PCAP_AIX:
826 bytes_to_read = sizeof (struct pcaprec_hdr);
829 case WTAP_FILE_PCAP_SS990417:
830 case WTAP_FILE_PCAP_SS991029:
831 bytes_to_read = sizeof (struct pcaprec_modified_hdr);
834 case WTAP_FILE_PCAP_SS990915:
835 bytes_to_read = sizeof (struct pcaprec_ss990915_hdr);
838 case WTAP_FILE_PCAP_NOKIA:
839 bytes_to_read = sizeof (struct pcaprec_nokia_hdr);
843 g_assert_not_reached();
846 bytes_read = file_read(hdr, 1, bytes_to_read, wth->fh);
847 if (bytes_read != bytes_to_read) {
848 *err = file_error(wth->fh);
849 if (*err == 0 && bytes_read != 0) {
850 *err = WTAP_ERR_SHORT_READ;
855 adjust_header(wth, &hdr->hdr);
857 if (hdr->hdr.incl_len > WTAP_MAX_PACKET_SIZE) {
859 * Probably a corrupt capture file; return an error,
860 * so that our caller doesn't blow up trying to allocate
861 * space for an immensely-large packet, and so that
862 * the code to try to guess what type of libpcap file
863 * this is can tell when it's not the type we're guessing
867 g_message("pcap: File has %u-byte packet, bigger than maximum of %u",
868 hdr->hdr.incl_len, WTAP_MAX_PACKET_SIZE);
870 *err = WTAP_ERR_BAD_RECORD;
874 if (hdr->hdr.orig_len > WTAP_MAX_PACKET_SIZE) {
876 * Probably a corrupt capture file; return an error,
877 * so that our caller doesn't blow up trying to
878 * cope with a huge "real" packet length, and so that
879 * the code to try to guess what type of libpcap file
880 * this is can tell when it's not the type we're guessing
884 g_message("pcap: File has %u-byte packet, bigger than maximum of %u",
885 hdr->hdr.orig_len, WTAP_MAX_PACKET_SIZE);
887 *err = WTAP_ERR_BAD_RECORD;
895 adjust_header(wtap *wth, struct pcaprec_hdr *hdr)
897 if (wth->capture.pcap->byte_swapped) {
898 /* Byte-swap the record header fields. */
899 hdr->ts_sec = BSWAP32(hdr->ts_sec);
900 hdr->ts_usec = BSWAP32(hdr->ts_usec);
901 hdr->incl_len = BSWAP32(hdr->incl_len);
902 hdr->orig_len = BSWAP32(hdr->orig_len);
905 /* If this is AIX, convert the time stamp from seconds/nanoseconds
906 to seconds/microseconds. */
907 if (wth->file_type == WTAP_FILE_PCAP_AIX)
908 hdr->ts_usec = hdr->ts_usec/1000;
910 /* In file format version 2.3, the "incl_len" and "orig_len" fields
911 were swapped, in order to match the BPF header layout.
913 Unfortunately, some files were, according to a comment in the
914 "libpcap" source, written with version 2.3 in their headers
915 but without the interchanged fields, so if "incl_len" is
916 greater than "orig_len" - which would make no sense - we
917 assume that we need to swap them. */
918 if (wth->capture.pcap->version_major == 2 &&
919 (wth->capture.pcap->version_minor < 3 ||
920 (wth->capture.pcap->version_minor == 3 &&
921 hdr->incl_len > hdr->orig_len))) {
924 temp = hdr->orig_len;
925 hdr->orig_len = hdr->incl_len;
926 hdr->incl_len = temp;
931 libpcap_close(wtap *wth)
933 g_free(wth->capture.pcap);
936 int wtap_pcap_encap_to_wtap_encap(int encap)
940 for (i = 0; i < NUM_PCAP_ENCAPS; i++) {
941 if (pcap_to_wtap_map[i].dlt_value == encap)
942 return pcap_to_wtap_map[i].wtap_encap_value;
944 return WTAP_ENCAP_UNKNOWN;
947 static int wtap_wtap_encap_to_pcap_encap(int encap)
952 * Special-case WTAP_ENCAP_FDDI and WTAP_ENCAP_FDDI_BITSWAPPED;
953 * both of them get mapped to DLT_FDDI (even though that may
954 * mean that the bit order in the FDDI MAC addresses is wrong;
955 * so it goes - libpcap format doesn't record the byte order,
956 * so that's not fixable).
958 if (encap == WTAP_ENCAP_FDDI || encap == WTAP_ENCAP_FDDI_BITSWAPPED)
959 return 10; /* that's DLT_FDDI */
960 for (i = 0; i < NUM_PCAP_ENCAPS; i++) {
961 if (pcap_to_wtap_map[i].wtap_encap_value == encap)
962 return pcap_to_wtap_map[i].dlt_value;
967 /* Returns 0 if we could write the specified encapsulation type,
968 an error indication otherwise. */
969 int libpcap_dump_can_write_encap(int filetype, int encap)
971 /* Per-packet encapsulations aren't supported. */
972 if (encap == WTAP_ENCAP_PER_PACKET)
973 return WTAP_ERR_ENCAP_PER_PACKET_UNSUPPORTED;
975 if (wtap_wtap_encap_to_pcap_encap(encap) == -1)
976 return WTAP_ERR_UNSUPPORTED_ENCAP;
981 /* Returns TRUE on success, FALSE on failure; sets "*err" to an error code on
983 gboolean libpcap_dump_open(wtap_dumper *wdh, int *err)
986 struct pcap_hdr file_hdr;
989 /* This is a libpcap file */
990 wdh->subtype_write = libpcap_dump;
991 wdh->subtype_close = NULL;
993 /* Write the file header. */
994 switch (wdh->file_type) {
997 case WTAP_FILE_PCAP_SS990417: /* modified, but with the old magic, sigh */
998 case WTAP_FILE_PCAP_NOKIA: /* Nokia libpcap of some sort */
1002 case WTAP_FILE_PCAP_SS990915: /* new magic, extra crap */
1003 case WTAP_FILE_PCAP_SS991029:
1004 magic = PCAP_MODIFIED_MAGIC;
1008 /* We should never get here - our open routine
1009 should only get called for the types above. */
1010 *err = WTAP_ERR_UNSUPPORTED_FILE_TYPE;
1014 nwritten = fwrite(&magic, 1, sizeof magic, wdh->fh);
1015 if (nwritten != sizeof magic) {
1016 if (nwritten == 0 && ferror(wdh->fh))
1019 *err = WTAP_ERR_SHORT_WRITE;
1023 /* current "libpcap" format is 2.4 */
1024 file_hdr.version_major = 2;
1025 file_hdr.version_minor = 4;
1026 file_hdr.thiszone = 0; /* XXX - current offset? */
1027 file_hdr.sigfigs = 0; /* unknown, but also apparently unused */
1028 file_hdr.snaplen = wdh->snaplen;
1029 file_hdr.network = wtap_wtap_encap_to_pcap_encap(wdh->encap);
1030 nwritten = fwrite(&file_hdr, 1, sizeof file_hdr, wdh->fh);
1031 if (nwritten != sizeof file_hdr) {
1032 if (nwritten == 0 && ferror(wdh->fh))
1035 *err = WTAP_ERR_SHORT_WRITE;
1042 /* Write a record for a packet to a dump file.
1043 Returns TRUE on success, FALSE on failure. */
1044 static gboolean libpcap_dump(wtap_dumper *wdh, const struct wtap_pkthdr *phdr,
1045 const union wtap_pseudo_header *pseudo_header, const u_char *pd, int *err)
1047 struct pcaprec_ss990915_hdr rec_hdr;
1051 rec_hdr.hdr.ts_sec = phdr->ts.tv_sec;
1052 rec_hdr.hdr.ts_usec = phdr->ts.tv_usec;
1053 rec_hdr.hdr.incl_len = phdr->caplen;
1054 rec_hdr.hdr.orig_len = phdr->len;
1055 switch (wdh->file_type) {
1057 case WTAP_FILE_PCAP:
1058 hdr_size = sizeof (struct pcaprec_hdr);
1061 case WTAP_FILE_PCAP_SS990417: /* modified, but with the old magic, sigh */
1062 case WTAP_FILE_PCAP_SS991029:
1063 /* XXX - what should we supply here?
1065 Alexey's "libpcap" looks up the interface in the system's
1066 interface list if "ifindex" is non-zero, and prints
1067 the interface name. It ignores "protocol", and uses
1068 "pkt_type" to tag the packet as "host", "broadcast",
1069 "multicast", "other host", "outgoing", or "none of the
1070 above", but that's it.
1072 If the capture we're writing isn't a modified or
1073 RH 6.1 capture, we'd have to do some work to
1074 generate the packet type and interface index - and
1075 we can't generate the interface index unless we
1076 just did the capture ourselves in any case.
1078 I'm inclined to continue to punt; systems other than
1079 those with the older patch can read standard "libpcap"
1080 files, and systems with the older patch, e.g. RH 6.1,
1081 will just have to live with this. */
1082 rec_hdr.ifindex = 0;
1083 rec_hdr.protocol = 0;
1084 rec_hdr.pkt_type = 0;
1085 hdr_size = sizeof (struct pcaprec_modified_hdr);
1088 case WTAP_FILE_PCAP_SS990915: /* new magic, extra crap at the end */
1089 rec_hdr.ifindex = 0;
1090 rec_hdr.protocol = 0;
1091 rec_hdr.pkt_type = 0;
1094 hdr_size = sizeof (struct pcaprec_ss990915_hdr);
1097 case WTAP_FILE_PCAP_NOKIA: /* old magic, extra crap at the end */
1098 rec_hdr.ifindex = 0;
1099 rec_hdr.protocol = 0;
1100 rec_hdr.pkt_type = 0;
1103 hdr_size = sizeof (struct pcaprec_nokia_hdr);
1107 /* We should never get here - our open routine
1108 should only get called for the types above. */
1109 g_assert_not_reached();
1110 *err = WTAP_ERR_UNSUPPORTED_FILE_TYPE;
1114 nwritten = fwrite(&rec_hdr, 1, hdr_size, wdh->fh);
1115 if (nwritten != hdr_size) {
1116 if (nwritten == 0 && ferror(wdh->fh))
1119 *err = WTAP_ERR_SHORT_WRITE;
1122 nwritten = fwrite(pd, 1, phdr->caplen, wdh->fh);
1123 if (nwritten != phdr->caplen) {
1124 if (nwritten == 0 && ferror(wdh->fh))
1127 *err = WTAP_ERR_SHORT_WRITE;