3 * $Id: libpcap.c,v 1.66 2002/02/27 08:57:25 guy Exp $
6 * Copyright (c) 1998 by Gilbert Ramirez <gram@alumni.rice.edu>
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
233 * It is also used as the PF (Packet Filter) logging format beginning
234 * with OpenBSD 3.0; we use 17 for PF logs unless DLT_LANE8023 is
235 * defined with the value 17.
237 #if !defined(DLT_LANE8023) || (DLT_LANE8023 != 17)
238 { 17, WTAP_ENCAP_PFLOG },
242 * 18 is DLT_CIP in SuSE 6.3 libpcap; if it's the same as the
243 * DLT_CIP of 16 that the Alexey Kuznetzov patches for
244 * libpcap/tcpdump define, it's WTAP_ENCAP_LINUX_ATM_CLIP.
245 * I've not found any libpcap that uses it for any other purpose -
246 * hopefully nobody will do so in the future.
248 { 18, WTAP_ENCAP_LINUX_ATM_CLIP },
251 * 19 is DLT_ATM_CLIP in the libpcap/tcpdump patches in the
252 * recent versions I've seen of the Linux ATM distribution;
253 * I've not yet found any libpcap that uses it for any other
254 * purpose - hopefully nobody will do so in the future.
256 { 19, WTAP_ENCAP_LINUX_ATM_CLIP },
259 * 50 is DLT_PPP_SERIAL in NetBSD; it appears that DLT_PPP
260 * on BSD (at least according to standard tcpdump) has, as
261 * the first octet, an indication of whether the packet was
262 * transmitted or received (rather than having the standard
263 * PPP address value of 0xff), but that DLT_PPP_SERIAL puts
264 * a real live PPP header there, or perhaps a Cisco PPP header
265 * as per section 4.3.1 of RFC 1547 (implementations of this
266 * exist in various BSDs in "sys/net/if_spppsubr.c", and
267 * I think also exist either in standard Linux or in
268 * various Linux patches; the implementations show how to handle
269 * Cisco keepalive packets).
271 * However, I don't see any obvious place in FreeBSD "if_ppp.c"
272 * where anything other than the standard PPP header would be
273 * passed up. I see some stuff that sets the first octet
274 * to 0 for incoming and 1 for outgoing packets before applying
275 * a BPF filter to see whether to drop packets whose protocol
276 * field has the 0x8000 bit set, i.e. network control protocols -
277 * those are handed up to userland - but that code puts the
278 * address field back before passing the packet up.
280 * I also don't see anything immediately obvious that munges
281 * the address field for sync PPP, either.
283 * Ethereal currently assumes that if the first octet of a
284 * PPP frame is 0xFF, it's the address field and is followed
285 * by a control field and a 2-byte protocol, otherwise the
286 * address and control fields are absent and the frame begins
287 * with a protocol field. If we ever see a BSD/OS PPP
288 * capture, we'll have to handle it differently, and we may
289 * have to handle standard BSD captures differently if, in fact,
290 * they don't have 0xff 0x03 as the first two bytes - but, as per
291 * the two paragraphs preceding this, it's not clear that
292 * the address field *is* munged into an incoming/outgoing
293 * field when the packet is handed to the BPF device.
295 * For now, we just map DLT_PPP_SERIAL to WTAP_ENCAP_PPP, as
296 * we treat WTAP_ENCAP_PPP packets as if those beginning with
297 * 0xff have the standard RFC 1662 "PPP in HDLC-like Framing"
298 * 0xff 0x03 address/control header, and DLT_PPP_SERIAL frames
299 * appear to contain that unless they're Cisco frames (if we
300 * ever see a capture with them, we'd need to implement the
301 * RFC 1547 stuff, and the keepalive protocol stuff).
303 * We may have to distinguish between "PPP where if it doesn't
304 * begin with 0xff there's no HDLC encapsulation and the frame
305 * begins with the protocol field" (which is how we handle
306 * WTAP_ENCAP_PPP now) and "PPP where there's either HDLC
307 * encapsulation or Cisco PPP" (which is what DLT_PPP_SERIAL
310 * XXX - NetBSD has DLT_HDLC, which appears to be used for
311 * Cisco HDLC. Ideally, they should use DLT_PPP_SERIAL
312 * only for real live HDLC-encapsulated PPP, not for Cisco
315 { 50, WTAP_ENCAP_PPP },
318 * These are the values that libpcap 0.5 uses, in an attempt
319 * to work around the confusion decried above, and that Wiretap
320 * and Ethereal currently support.
322 * The next version of libpcap will probably not use them as
323 * DLT_ values in its API, but will probably use them in capture
326 { 100, WTAP_ENCAP_ATM_RFC1483 },
327 { 101, WTAP_ENCAP_RAW_IP },
330 * More values used by libpcap 0.5 as DLT_ values and used by the
331 * current CVS version of libpcap in capture file headers.
332 * They are not yet handled in Ethereal.
333 * If we get a capture that contains them, we'll implement them.
335 { 102, WTAP_ENCAP_SLIP_BSDOS },
336 { 103, WTAP_ENCAP_PPP_BSDOS },
340 * These ones are handled in Ethereal, though.
342 { 104, WTAP_ENCAP_CHDLC }, /* Cisco HDLC */
343 { 106, WTAP_ENCAP_LINUX_ATM_CLIP },
346 * Values not yet used by the current CVS version of libpcap,
347 * but reserved for future use; the IEEE 802.11 value is
348 * there for use with a capture program from Axis Communications.
350 { 105, WTAP_ENCAP_IEEE_802_11 },
353 * Not yet handled in Ethereal; we don't know what encapsulation
354 * BSD/OS uses, so we don't know whether it can be handed to
355 * the Frame Relay dissector or not.
357 { 107, WTAP_ENCAP_FR }, /* Frame Relay */
359 { 108, WTAP_ENCAP_NULL }, /* OpenBSD loopback */
361 { 109, WTAP_ENCAP_ENC }, /* OpenBSD IPSEC enc */
362 { 110, WTAP_ENCAP_LANE_802_3 },/* ATM LANE 802.3 */
363 { 111, WTAP_ENCAP_HIPPI }, /* NetBSD HIPPI */
365 { 112, WTAP_ENCAP_CHDLC }, /* NetBSD HDLC framing */
368 * Linux "cooked mode" captures, used by the current CVS version
371 { 113, WTAP_ENCAP_SLL }, /* Linux cooked capture */
373 { 114, WTAP_ENCAP_LOCALTALK }, /* Localtalk */
376 * The tcpdump.org version of libpcap uses 117, rather than 17,
377 * for OpenBSD packet filter logging, so as to avoid conflicting
378 * with DLT_LANE8023 in SuSE 6.3 libpcap.
380 { 117, WTAP_ENCAP_PFLOG },
382 { 118, WTAP_ENCAP_CISCO_IOS },
383 { 119, WTAP_ENCAP_PRISM_HEADER }, /* Prism monitor mode hdr */
384 { 121, WTAP_ENCAP_HHDLC }, /* HiPath HDLC */
386 #define NUM_PCAP_ENCAPS (sizeof pcap_to_wtap_map / sizeof pcap_to_wtap_map[0])
388 int libpcap_open(wtap *wth, int *err)
393 gboolean byte_swapped;
398 /* Read in the number that should be at the start of a "libpcap" file */
399 errno = WTAP_ERR_CANT_READ;
400 bytes_read = file_read(&magic, 1, sizeof magic, wth->fh);
401 if (bytes_read != sizeof magic) {
402 *err = file_error(wth->fh);
407 wth->data_offset += sizeof magic;
412 /* Host that wrote it has our byte order, and was running
413 a program using either standard or ss990417 libpcap. */
414 byte_swapped = FALSE;
418 case PCAP_MODIFIED_MAGIC:
419 /* Host that wrote it has our byte order, and was running
420 a program using either ss990915 or ss991029 libpcap. */
421 byte_swapped = FALSE;
425 case PCAP_SWAPPED_MAGIC:
426 /* Host that wrote it has a byte order opposite to ours,
427 and was running a program using either standard or
433 case PCAP_SWAPPED_MODIFIED_MAGIC:
434 /* Host that wrote it out has a byte order opposite to
435 ours, and was running a program using either ss990915
436 or ss991029 libpcap. */
442 /* Not a "libpcap" type we know about. */
446 /* Read the rest of the header. */
447 errno = WTAP_ERR_CANT_READ;
448 bytes_read = file_read(&hdr, 1, sizeof hdr, wth->fh);
449 if (bytes_read != sizeof hdr) {
450 *err = file_error(wth->fh);
455 wth->data_offset += sizeof hdr;
458 /* Byte-swap the header fields about which we care. */
459 hdr.version_major = BSWAP16(hdr.version_major);
460 hdr.version_minor = BSWAP16(hdr.version_minor);
461 hdr.snaplen = BSWAP32(hdr.snaplen);
462 hdr.network = BSWAP32(hdr.network);
464 if (hdr.version_major < 2) {
465 /* We only support version 2.0 and later. */
466 g_message("pcap: major version %u unsupported",
468 *err = WTAP_ERR_UNSUPPORTED;
473 * AIX's non-standard tcpdump uses a minor version number of 2.
474 * Unfortunately, older versions of libpcap might have used
477 * The AIX libpcap uses RFC 1573 ifType values rather than
478 * DLT_ values in the header; the ifType values for LAN devices
485 * which correspond to DLT_IEEE802 (used for Token Ring),
486 * DLT_PPP, and DLT_SLIP_BSDOS, respectively. We shall
487 * assume that if the minor version number is 2, and
488 * the network type is 6, 9, or 15, that it's AIX libpcap;
490 * I'm assuming those older versions of libpcap didn't
491 * use DLT_IEEE802 for Token Ring, and didn't use DLT_SLIP_BSDOS
492 * as that came later. It may have used DLT_SLIP, however, in
493 * which case we're out of luck; we assume it's Token Ring
494 * in AIX libpcap rather than PPP in standard libpcap, as
495 * you're probably more likely to be handing an AIX libpcap
496 * token-ring capture than an old (pre-libpcap 0.4) PPP capture
499 aix = FALSE; /* assume it's not AIX */
500 if (hdr.version_major == 2 && hdr.version_minor == 2) {
501 switch (hdr.network) {
504 hdr.network = 1; /* DLT_EN10MB, Ethernet */
509 hdr.network = 6; /* DLT_IEEE802, Token Ring */
514 hdr.network = 10; /* DLT_FDDI, FDDI */
519 file_encap = wtap_pcap_encap_to_wtap_encap(hdr.network);
520 if (file_encap == WTAP_ENCAP_UNKNOWN) {
521 g_message("pcap: network type %u unknown or unsupported",
523 *err = WTAP_ERR_UNSUPPORTED_ENCAP;
527 /* This is a libpcap file */
528 wth->capture.pcap = g_malloc(sizeof(libpcap_t));
529 wth->capture.pcap->byte_swapped = byte_swapped;
530 wth->capture.pcap->version_major = hdr.version_major;
531 wth->capture.pcap->version_minor = hdr.version_minor;
532 wth->subtype_read = libpcap_read;
533 wth->subtype_seek_read = wtap_def_seek_read;
534 wth->subtype_close = libpcap_close;
535 wth->file_encap = file_encap;
536 wth->snapshot_length = hdr.snaplen;
539 * Is this AIX format?
543 * Yes. Skip all the tests for other mutant formats.
545 wth->file_type = WTAP_FILE_PCAP_AIX;
550 * No. Let's look at the header for the first record,
551 * and see if, interpreting it as a standard header (if the
552 * magic number was standard) or a modified header (if the
553 * magic number was modified), the position where it says the
554 * header for the *second* record is contains a corrupted header.
558 * If this file had the standard magic number, it may be
559 * an ss990417 capture file - in that version of Alexey's
560 * patch, the packet header format was changed but the
561 * magic number wasn't, and, alas, Red Hat appear to have
562 * picked up that version of the patch for RH 6.1, meaning
563 * RH 6.1 has a tcpdump that writes out files that can't
564 * be read by any software that expects non-modified headers
565 * if the magic number isn't the modified magic number (e.g.,
566 * any normal version of tcpdump, and Ethereal if we don't
567 * do this gross heuristic).
569 * If this file had the modified magic number, it may be
570 * an ss990915 capture file - in that version of Alexey's
571 * patch, the magic number was changed, but the record
572 * header had some extra fields, and, alas, SuSE appear
573 * to have picked up that version of the patch for SuSE
574 * 6.3, meaning that programs expecting the standard per-
575 * packet header in captures with the modified magic number
576 * can't read dumps from its tcpdump.
578 * Oh, and if it has the standard magic number, it might, instead,
579 * be a Nokia libpcap file, so we may need to try that if
580 * neither normal nor ss990417 headers work.
584 * Well, we have the magic number from Alexey's
587 * Try ss991029, the last of his patches, first.
589 wth->file_type = WTAP_FILE_PCAP_SS991029;
590 switch (libpcap_try(wth, err)) {
594 * Well, we couldn't even read it.
601 * Well, it looks as if it might be 991029.
602 * Put the seek pointer back, and return success.
604 file_seek(wth->fh, wth->data_offset, SEEK_SET);
609 * Try the next format.
615 * Well, it's not completely unreadable,
616 * but it's not ss991029. Try ss990915;
617 * there are no other types to try after that,
618 * so we put the seek pointer back and treat
621 wth->file_type = WTAP_FILE_PCAP_SS990915;
622 file_seek(wth->fh, wth->data_offset, SEEK_SET);
625 * Well, we have the standard magic number.
627 * Try the standard format first.
629 wth->file_type = WTAP_FILE_PCAP;
630 switch (libpcap_try(wth, err)) {
634 * Well, we couldn't even read it.
641 * Well, it looks as if it might be a standard
643 * Put the seek pointer back, and return success.
645 file_seek(wth->fh, wth->data_offset, SEEK_SET);
650 * Try the next format.
656 * Well, it's not completely unreadable, but it's not
657 * a standard file. Put the seek pointer back and try
660 wth->file_type = WTAP_FILE_PCAP_SS990417;
661 file_seek(wth->fh, wth->data_offset, SEEK_SET);
662 switch (libpcap_try(wth, err)) {
666 * Well, we couldn't even read it.
673 * Well, it looks as if it might be ss990417.
674 * Put the seek pointer back, and return success.
676 file_seek(wth->fh, wth->data_offset, SEEK_SET);
681 * Try the next format.
687 * Well, it's not completely unreadable,
688 * but it's not a standard file *nor* is it ss990417.
689 * Try it as a Nokia file; there are no other types
690 * to try after that, so we put the seek pointer back
691 * and treat it as a Nokia file.
693 wth->file_type = WTAP_FILE_PCAP_NOKIA;
694 file_seek(wth->fh, wth->data_offset, SEEK_SET);
700 /* Try to read the first two records of the capture file. */
701 static libpcap_try_t libpcap_try(wtap *wth, int *err)
704 * pcaprec_ss990915_hdr is the largest header type.
706 struct pcaprec_ss990915_hdr first_rec_hdr, second_rec_hdr;
709 * Attempt to read the first record's header.
711 if (libpcap_read_header(wth, err, &first_rec_hdr, TRUE) == -1) {
712 if (*err == 0 || *err == WTAP_ERR_SHORT_READ) {
714 * EOF or short read - assume the file is in this
716 * When our client tries to read the first packet
717 * they will presumably get the same EOF or short
723 if (*err == WTAP_ERR_BAD_RECORD) {
725 * The first record is bogus, so this is probably
726 * a corrupt file. Assume the file is in this
727 * format. When our client tries to read the
728 * first packet they will presumably get the
735 * Some other error, e.g. an I/O error; just give up.
741 * Now skip over the first record's data, under the assumption
742 * that the header is sane.
744 file_seek(wth->fh, first_rec_hdr.hdr.incl_len, SEEK_CUR);
747 * Now attempt to read the second record's header.
749 if (libpcap_read_header(wth, err, &second_rec_hdr, TRUE) == -1) {
750 if (*err == 0 || *err == WTAP_ERR_SHORT_READ) {
752 * EOF or short read - assume the file is in this
754 * When our client tries to read the second packet
755 * they will presumably get the same EOF or short
761 if (*err == WTAP_ERR_BAD_RECORD) {
763 * The second record is bogus; maybe it's a
764 * Capture File From Hell, and what looks like
765 * the "header" of the next packet is actually
766 * random junk from the middle of a packet.
767 * Try the next format; if we run out of formats,
768 * it probably *is* a corrupt file.
774 * Some other error, e.g. an I/O error; just give up.
780 * OK, the first two records look OK; assume this is the
786 /* Read the next packet */
787 static gboolean libpcap_read(wtap *wth, int *err, long *data_offset)
789 struct pcaprec_ss990915_hdr hdr;
793 bytes_read = libpcap_read_header(wth, err, &hdr, FALSE);
794 if (bytes_read == -1) {
796 * We failed to read the header.
801 wth->data_offset += bytes_read;
802 packet_size = hdr.hdr.incl_len;
804 buffer_assure_space(wth->frame_buffer, packet_size);
805 *data_offset = wth->data_offset;
806 errno = WTAP_ERR_CANT_READ;
807 bytes_read = file_read(buffer_start_ptr(wth->frame_buffer), 1,
808 packet_size, wth->fh);
810 if ((guint)bytes_read != packet_size) {
811 *err = file_error(wth->fh);
813 *err = WTAP_ERR_SHORT_READ;
816 wth->data_offset += packet_size;
818 wth->phdr.ts.tv_sec = hdr.hdr.ts_sec;
819 wth->phdr.ts.tv_usec = hdr.hdr.ts_usec;
820 wth->phdr.caplen = packet_size;
821 wth->phdr.len = hdr.hdr.orig_len;
822 wth->phdr.pkt_encap = wth->file_encap;
827 /* Read the header of the next packet; if "silent" is TRUE, don't complain
828 to the console, as we're testing to see if the file appears to be of a
831 Return -1 on an error, or the number of bytes of header read on success. */
832 static int libpcap_read_header(wtap *wth, int *err,
833 struct pcaprec_ss990915_hdr *hdr, gboolean silent)
835 int bytes_to_read, bytes_read;
837 /* Read record header. */
838 errno = WTAP_ERR_CANT_READ;
839 switch (wth->file_type) {
842 case WTAP_FILE_PCAP_AIX:
843 bytes_to_read = sizeof (struct pcaprec_hdr);
846 case WTAP_FILE_PCAP_SS990417:
847 case WTAP_FILE_PCAP_SS991029:
848 bytes_to_read = sizeof (struct pcaprec_modified_hdr);
851 case WTAP_FILE_PCAP_SS990915:
852 bytes_to_read = sizeof (struct pcaprec_ss990915_hdr);
855 case WTAP_FILE_PCAP_NOKIA:
856 bytes_to_read = sizeof (struct pcaprec_nokia_hdr);
860 g_assert_not_reached();
863 bytes_read = file_read(hdr, 1, bytes_to_read, wth->fh);
864 if (bytes_read != bytes_to_read) {
865 *err = file_error(wth->fh);
866 if (*err == 0 && bytes_read != 0) {
867 *err = WTAP_ERR_SHORT_READ;
872 adjust_header(wth, &hdr->hdr);
874 if (hdr->hdr.incl_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 allocate
878 * space for an immensely-large packet, 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.incl_len, WTAP_MAX_PACKET_SIZE);
887 *err = WTAP_ERR_BAD_RECORD;
891 if (hdr->hdr.orig_len > WTAP_MAX_PACKET_SIZE) {
893 * Probably a corrupt capture file; return an error,
894 * so that our caller doesn't blow up trying to
895 * cope with a huge "real" packet length, and so that
896 * the code to try to guess what type of libpcap file
897 * this is can tell when it's not the type we're guessing
901 g_message("pcap: File has %u-byte packet, bigger than maximum of %u",
902 hdr->hdr.orig_len, WTAP_MAX_PACKET_SIZE);
904 *err = WTAP_ERR_BAD_RECORD;
912 adjust_header(wtap *wth, struct pcaprec_hdr *hdr)
914 if (wth->capture.pcap->byte_swapped) {
915 /* Byte-swap the record header fields. */
916 hdr->ts_sec = BSWAP32(hdr->ts_sec);
917 hdr->ts_usec = BSWAP32(hdr->ts_usec);
918 hdr->incl_len = BSWAP32(hdr->incl_len);
919 hdr->orig_len = BSWAP32(hdr->orig_len);
922 /* If this is AIX, convert the time stamp from seconds/nanoseconds
923 to seconds/microseconds. */
924 if (wth->file_type == WTAP_FILE_PCAP_AIX)
925 hdr->ts_usec = hdr->ts_usec/1000;
927 /* In file format version 2.3, the "incl_len" and "orig_len" fields
928 were swapped, in order to match the BPF header layout.
930 Unfortunately, some files were, according to a comment in the
931 "libpcap" source, written with version 2.3 in their headers
932 but without the interchanged fields, so if "incl_len" is
933 greater than "orig_len" - which would make no sense - we
934 assume that we need to swap them. */
935 if (wth->capture.pcap->version_major == 2 &&
936 (wth->capture.pcap->version_minor < 3 ||
937 (wth->capture.pcap->version_minor == 3 &&
938 hdr->incl_len > hdr->orig_len))) {
941 temp = hdr->orig_len;
942 hdr->orig_len = hdr->incl_len;
943 hdr->incl_len = temp;
948 libpcap_close(wtap *wth)
950 g_free(wth->capture.pcap);
953 int wtap_pcap_encap_to_wtap_encap(int encap)
957 for (i = 0; i < NUM_PCAP_ENCAPS; i++) {
958 if (pcap_to_wtap_map[i].dlt_value == encap)
959 return pcap_to_wtap_map[i].wtap_encap_value;
961 return WTAP_ENCAP_UNKNOWN;
964 static int wtap_wtap_encap_to_pcap_encap(int encap)
969 * Special-case WTAP_ENCAP_FDDI and WTAP_ENCAP_FDDI_BITSWAPPED;
970 * both of them get mapped to DLT_FDDI (even though that may
971 * mean that the bit order in the FDDI MAC addresses is wrong;
972 * so it goes - libpcap format doesn't record the byte order,
973 * so that's not fixable).
975 if (encap == WTAP_ENCAP_FDDI || encap == WTAP_ENCAP_FDDI_BITSWAPPED)
976 return 10; /* that's DLT_FDDI */
977 for (i = 0; i < NUM_PCAP_ENCAPS; i++) {
978 if (pcap_to_wtap_map[i].wtap_encap_value == encap)
979 return pcap_to_wtap_map[i].dlt_value;
984 /* Returns 0 if we could write the specified encapsulation type,
985 an error indication otherwise. */
986 int libpcap_dump_can_write_encap(int encap)
988 /* Per-packet encapsulations aren't supported. */
989 if (encap == WTAP_ENCAP_PER_PACKET)
990 return WTAP_ERR_ENCAP_PER_PACKET_UNSUPPORTED;
992 if (wtap_wtap_encap_to_pcap_encap(encap) == -1)
993 return WTAP_ERR_UNSUPPORTED_ENCAP;
998 /* Returns TRUE on success, FALSE on failure; sets "*err" to an error code on
1000 gboolean libpcap_dump_open(wtap_dumper *wdh, int *err)
1003 struct pcap_hdr file_hdr;
1006 /* This is a libpcap file */
1007 wdh->subtype_write = libpcap_dump;
1008 wdh->subtype_close = NULL;
1010 /* Write the file header. */
1011 switch (wdh->file_type) {
1013 case WTAP_FILE_PCAP:
1014 case WTAP_FILE_PCAP_SS990417: /* modified, but with the old magic, sigh */
1015 case WTAP_FILE_PCAP_NOKIA: /* Nokia libpcap of some sort */
1019 case WTAP_FILE_PCAP_SS990915: /* new magic, extra crap */
1020 case WTAP_FILE_PCAP_SS991029:
1021 magic = PCAP_MODIFIED_MAGIC;
1025 /* We should never get here - our open routine
1026 should only get called for the types above. */
1027 *err = WTAP_ERR_UNSUPPORTED_FILE_TYPE;
1031 nwritten = fwrite(&magic, 1, sizeof magic, wdh->fh);
1032 if (nwritten != sizeof magic) {
1033 if (nwritten == 0 && ferror(wdh->fh))
1036 *err = WTAP_ERR_SHORT_WRITE;
1039 wdh->bytes_dumped += sizeof magic;
1041 /* current "libpcap" format is 2.4 */
1042 file_hdr.version_major = 2;
1043 file_hdr.version_minor = 4;
1044 file_hdr.thiszone = 0; /* XXX - current offset? */
1045 file_hdr.sigfigs = 0; /* unknown, but also apparently unused */
1046 file_hdr.snaplen = wdh->snaplen;
1047 file_hdr.network = wtap_wtap_encap_to_pcap_encap(wdh->encap);
1048 nwritten = fwrite(&file_hdr, 1, sizeof file_hdr, wdh->fh);
1049 if (nwritten != sizeof file_hdr) {
1050 if (nwritten == 0 && ferror(wdh->fh))
1053 *err = WTAP_ERR_SHORT_WRITE;
1056 wdh->bytes_dumped += sizeof file_hdr;
1061 /* Write a record for a packet to a dump file.
1062 Returns TRUE on success, FALSE on failure. */
1063 static gboolean libpcap_dump(wtap_dumper *wdh, const struct wtap_pkthdr *phdr,
1064 const union wtap_pseudo_header *pseudo_header, const u_char *pd, int *err)
1066 struct pcaprec_ss990915_hdr rec_hdr;
1070 rec_hdr.hdr.ts_sec = phdr->ts.tv_sec;
1071 rec_hdr.hdr.ts_usec = phdr->ts.tv_usec;
1072 rec_hdr.hdr.incl_len = phdr->caplen;
1073 rec_hdr.hdr.orig_len = phdr->len;
1074 switch (wdh->file_type) {
1076 case WTAP_FILE_PCAP:
1077 hdr_size = sizeof (struct pcaprec_hdr);
1080 case WTAP_FILE_PCAP_SS990417: /* modified, but with the old magic, sigh */
1081 case WTAP_FILE_PCAP_SS991029:
1082 /* XXX - what should we supply here?
1084 Alexey's "libpcap" looks up the interface in the system's
1085 interface list if "ifindex" is non-zero, and prints
1086 the interface name. It ignores "protocol", and uses
1087 "pkt_type" to tag the packet as "host", "broadcast",
1088 "multicast", "other host", "outgoing", or "none of the
1089 above", but that's it.
1091 If the capture we're writing isn't a modified or
1092 RH 6.1 capture, we'd have to do some work to
1093 generate the packet type and interface index - and
1094 we can't generate the interface index unless we
1095 just did the capture ourselves in any case.
1097 I'm inclined to continue to punt; systems other than
1098 those with the older patch can read standard "libpcap"
1099 files, and systems with the older patch, e.g. RH 6.1,
1100 will just have to live with this. */
1101 rec_hdr.ifindex = 0;
1102 rec_hdr.protocol = 0;
1103 rec_hdr.pkt_type = 0;
1104 hdr_size = sizeof (struct pcaprec_modified_hdr);
1107 case WTAP_FILE_PCAP_SS990915: /* new magic, extra crap at the end */
1108 rec_hdr.ifindex = 0;
1109 rec_hdr.protocol = 0;
1110 rec_hdr.pkt_type = 0;
1113 hdr_size = sizeof (struct pcaprec_ss990915_hdr);
1116 case WTAP_FILE_PCAP_NOKIA: /* old magic, extra crap at the end */
1117 rec_hdr.ifindex = 0;
1118 rec_hdr.protocol = 0;
1119 rec_hdr.pkt_type = 0;
1122 hdr_size = sizeof (struct pcaprec_nokia_hdr);
1126 /* We should never get here - our open routine
1127 should only get called for the types above. */
1128 g_assert_not_reached();
1129 *err = WTAP_ERR_UNSUPPORTED_FILE_TYPE;
1133 nwritten = fwrite(&rec_hdr, 1, hdr_size, wdh->fh);
1134 if (nwritten != hdr_size) {
1135 if (nwritten == 0 && ferror(wdh->fh))
1138 *err = WTAP_ERR_SHORT_WRITE;
1141 wdh->bytes_dumped += hdr_size;
1142 nwritten = fwrite(pd, 1, phdr->caplen, wdh->fh);
1143 if (nwritten != phdr->caplen) {
1144 if (nwritten == 0 && ferror(wdh->fh))
1147 *err = WTAP_ERR_SHORT_WRITE;
1150 wdh->bytes_dumped += phdr->caplen;