The Tcpdump Group git mirrors - libpcap/blob - savefile.c

   1 /*
   2  * Copyright (c) 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  *
  21  * savefile.c - supports offline use of tcpdump
  22  *      Extraction/creation by Jeffrey Mogul, DECWRL
  23  *      Modified by Steve McCanne, LBL.
  24  *
  25  * Used to save the received packet headers, after filtering, to
  26  * a file, and then read them later.
  27  * The first record in the file contains saved values for the machine
  28  * dependent values so we can print the dump file on any architecture.
  29  */
  30
  31 #ifndef lint
  32 static const char rcsid[] _U_ =
  33     "@(#) $Header: /tcpdump/master/libpcap/savefile.c,v 1.97 2003-11-20 02:02:41 guy Exp $ (LBL)";
  34 #endif
  35
  36 #ifdef HAVE_CONFIG_H
  37 #include "config.h"
  38 #endif
  39
  40 #include <errno.h>
  41 #include <memory.h>
  42 #include <stdio.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45
  46 #include "pcap-int.h"
  47
  48 #ifdef HAVE_OS_PROTO_H
  49 #include "os-proto.h"
  50 #endif
  51
  52 #define TCPDUMP_MAGIC 0xa1b2c3d4
  53 #define PATCHED_TCPDUMP_MAGIC 0xa1b2cd34
  54
  55 /*
  56  * We use the "receiver-makes-right" approach to byte order,
  57  * because time is at a premium when we are writing the file.
  58  * In other words, the pcap_file_header and pcap_pkthdr,
  59  * records are written in host byte order.
  60  * Note that the bytes of packet data are written out in the order in
  61  * which they were received, so multi-byte fields in packets are not
  62  * written in host byte order, they're written in whatever order the
  63  * sending machine put them in.
  64  *
  65  * ntoh[ls] aren't sufficient because we might need to swap on a big-endian
  66  * machine (if the file was written in little-end order).
  67  */
  68 #define SWAPLONG(y) \
  69 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
  70 #define SWAPSHORT(y) \
  71         ( (((y)&0xff)<<8) | ((u_short)((y)&0xff00)>>8) )
  72
  73 #define SFERR_TRUNC             1
  74 #define SFERR_BADVERSION        2
  75 #define SFERR_BADF              3
  76 #define SFERR_EOF               4 /* not really an error, just a status */
  77
  78 /*
  79  * We don't write DLT_* values to the capture file header, because
  80  * they're not the same on all platforms.
  81  *
  82  * Unfortunately, the various flavors of BSD have not always used the same
  83  * numerical values for the same data types, and various patches to
  84  * libpcap for non-BSD OSes have added their own DLT_* codes for link
  85  * layer encapsulation types seen on those OSes, and those codes have had,
  86  * in some cases, values that were also used, on other platforms, for other
  87  * link layer encapsulation types.
  88  *
  89  * This means that capture files of a type whose numerical DLT_* code
  90  * means different things on different BSDs, or with different versions
  91  * of libpcap, can't always be read on systems other than those like
  92  * the one running on the machine on which the capture was made.
  93  *
  94  * Instead, we define here a set of LINKTYPE_* codes, and map DLT_* codes
  95  * to LINKTYPE_* codes when writing a savefile header, and map LINKTYPE_*
  96  * codes to DLT_* codes when reading a savefile header.
  97  *
  98  * For those DLT_* codes that have, as far as we know, the same values on
  99  * all platforms (DLT_NULL through DLT_FDDI), we define LINKTYPE_xxx as
 100  * DLT_xxx; that way, captures of those types can still be read by
 101  * versions of libpcap that map LINKTYPE_* values to DLT_* values, and
 102  * captures of those types written by versions of libpcap that map DLT_
 103  * values to LINKTYPE_ values can still be read by older versions
 104  * of libpcap.
 105  *
 106  * The other LINKTYPE_* codes are given values starting at 100, in the
 107  * hopes that no DLT_* code will be given one of those values.
 108  *
 109  * In order to ensure that a given LINKTYPE_* code's value will refer to
 110  * the same encapsulation type on all platforms, you should not allocate
 111  * a new LINKTYPE_* value without consulting "tcpdump-workers@tcpdump.org".
 112  * The tcpdump developers will allocate a value for you, and will not
 113  * subsequently allocate it to anybody else; that value will be added to
 114  * the "pcap.h" in the tcpdump.org CVS repository, so that a future
 115  * libpcap release will include it.
 116  *
 117  * You should, if possible, also contribute patches to libpcap and tcpdump
 118  * to handle the new encapsulation type, so that they can also be checked
 119  * into the tcpdump.org CVS repository and so that they will appear in
 120  * future libpcap and tcpdump releases.
 121  */
 122 #define LINKTYPE_NULL           DLT_NULL
 123 #define LINKTYPE_ETHERNET       DLT_EN10MB      /* also for 100Mb and up */
 124 #define LINKTYPE_EXP_ETHERNET   DLT_EN3MB       /* 3Mb experimental Ethernet */
 125 #define LINKTYPE_AX25           DLT_AX25
 126 #define LINKTYPE_PRONET         DLT_PRONET
 127 #define LINKTYPE_CHAOS          DLT_CHAOS
 128 #define LINKTYPE_TOKEN_RING     DLT_IEEE802     /* DLT_IEEE802 is used for Token Ring */
 129 #define LINKTYPE_ARCNET         DLT_ARCNET      /* BSD-style headers */
 130 #define LINKTYPE_SLIP           DLT_SLIP
 131 #define LINKTYPE_PPP            DLT_PPP
 132 #define LINKTYPE_FDDI           DLT_FDDI
 133
 134 /*
 135  * LINKTYPE_PPP is for use when there might, or might not, be an RFC 1662
 136  * PPP in HDLC-like framing header (with 0xff 0x03 before the PPP protocol
 137  * field) at the beginning of the packet.
 138  *
 139  * This is for use when there is always such a header; the address field
 140  * might be 0xff, for regular PPP, or it might be an address field for Cisco
 141  * point-to-point with HDLC framing as per section 4.3.1 of RFC 1547 ("Cisco
 142  * HDLC").  This is, for example, what you get with NetBSD's DLT_PPP_SERIAL.
 143  *
 144  * We give it the same value as NetBSD's DLT_PPP_SERIAL, in the hopes that
 145  * nobody else will choose a DLT_ value of 50, and so that DLT_PPP_SERIAL
 146  * captures will be written out with a link type that NetBSD's tcpdump
 147  * can read.
 148  */
 149 #define LINKTYPE_PPP_HDLC       50              /* PPP in HDLC-like framing */
 150
 151 #define LINKTYPE_PPP_ETHER      51              /* NetBSD PPP-over-Ethernet */
 152
 153 #define LINKTYPE_ATM_RFC1483    100             /* LLC/SNAP-encapsulated ATM */
 154 #define LINKTYPE_RAW            101             /* raw IP */
 155 #define LINKTYPE_SLIP_BSDOS     102             /* BSD/OS SLIP BPF header */
 156 #define LINKTYPE_PPP_BSDOS      103             /* BSD/OS PPP BPF header */
 157 #define LINKTYPE_C_HDLC         104             /* Cisco HDLC */
 158 #define LINKTYPE_IEEE802_11     105             /* IEEE 802.11 (wireless) */
 159 #define LINKTYPE_ATM_CLIP       106             /* Linux Classical IP over ATM */
 160 #define LINKTYPE_FRELAY         107             /* Frame Relay */
 161 #define LINKTYPE_LOOP           108             /* OpenBSD loopback */
 162 #define LINKTYPE_ENC            109             /* OpenBSD IPSEC enc */
 163
 164 #define LINKTYPE_LINUX_SLL      113             /* Linux cooked socket capture */
 165 #define LINKTYPE_LTALK          114             /* Apple LocalTalk hardware */
 166 #define LINKTYPE_ECONET         115             /* Acorn Econet */
 167
 168 #define LINKTYPE_PFLOG          117             /* OpenBSD DLT_PFLOG */
 169 #define LINKTYPE_CISCO_IOS      118             /* For Cisco-internal use */
 170 #define LINKTYPE_PRISM_HEADER   119             /* 802.11+Prism II monitor mode */
 171 #define LINKTYPE_AIRONET_HEADER 120             /* FreeBSD Aironet driver stuff */
 172 #define LINKTYPE_IP_OVER_FC     122             /* RFC 2625 IP-over-Fibre Channel */
 173 #define LINKTYPE_SUNATM         123             /* Solaris+SunATM */
 174
 175 #define LINKTYPE_IEEE802_11_RADIO 127           /* 802.11 plus WLAN header */
 176
 177 #define LINKTYPE_TZSP           128             /* Tazmen Sniffer Protocol */
 178
 179 #define LINKTYPE_ARCNET_LINUX   129             /* Linux-style headers */
 180
 181 #define LINKTYPE_JUNIPER_MLPPP  130             /* Juniper-internal chassis encapsulation */
 182 #define LINKTYPE_JUNIPER_MLFR   131
 183 #define LINKTYPE_JUNIPER_ES     132
 184 #define LINKTYPE_JUNIPER_GGSN   133
 185 #define LINKTYPE_JUNIPER_MFR    134
 186 #define LINKTYPE_JUNIPER_ATM2   135
 187 #define LINKTYPE_JUNIPER_SERVICES 136
 188 #define LINKTYPE_JUNIPER_ATM1   137
 189
 190 #define LINKTYPE_APPLE_IP_OVER_IEEE1394 138     /* Apple IP-over-IEEE 1394 cooked header */
 191
 192 #define LINKTYPE_RAWSS7         139             /* see rawss7.h for */
 193 #define LINKTYPE_RAWSS7_MTP2    140             /* information  on these */
 194 #define LINKTYPE_RAWSS7_MTP3    141             /* definitions */
 195 #define LINKTYPE_RAWSS7_SCCP    142
 196
 197 #define LINKTYPE_DOCSIS         143             /* DOCSIS MAC frames */
 198
 199 #define LINKTYPE_LINUX_IRDA     144             /* Linux-IrDA */
 200
 201 /*
 202  * These types are reserved for future use.
 203  */
 204 #define LINKTYPE_LANE8023       110             /* ATM LANE + 802.3 */
 205 #define LINKTYPE_HIPPI          111             /* NetBSD HIPPI */
 206 #define LINKTYPE_HDLC           112             /* NetBSD HDLC framing */
 207 #define LINKTYPE_IPFILTER       116             /* IP Filter capture files */
 208 #define LINKTYPE_HHDLC          121             /* Siemens HiPath HDLC */
 209 #define LINKTYPE_RIO            124             /* RapidIO */
 210 #define LINKTYPE_PCI_EXP        125             /* PCI Express */
 211 #define LINKTYPE_AURORA         126             /* Xilinx Aurora link layer */
 212
 213 static struct linktype_map {
 214         int     dlt;
 215         int     linktype;
 216 } map[] = {
 217         /*
 218          * These DLT_* codes have LINKTYPE_* codes with values identical
 219          * to the values of the corresponding DLT_* code.
 220          */
 221         { DLT_NULL,             LINKTYPE_NULL },
 222         { DLT_EN10MB,           LINKTYPE_ETHERNET },
 223         { DLT_EN3MB,            LINKTYPE_EXP_ETHERNET },
 224         { DLT_AX25,             LINKTYPE_AX25 },
 225         { DLT_PRONET,           LINKTYPE_PRONET },
 226         { DLT_CHAOS,            LINKTYPE_CHAOS },
 227         { DLT_IEEE802,          LINKTYPE_TOKEN_RING },
 228         { DLT_ARCNET,           LINKTYPE_ARCNET },
 229         { DLT_SLIP,             LINKTYPE_SLIP },
 230         { DLT_PPP,              LINKTYPE_PPP },
 231         { DLT_FDDI,             LINKTYPE_FDDI },
 232
 233         /*
 234          * These DLT_* codes have different values on different
 235          * platforms; we map them to LINKTYPE_* codes that
 236          * have values that should never be equal to any DLT_*
 237          * code.
 238          */
 239 #ifdef DLT_FR
 240         /* BSD/OS Frame Relay */
 241         { DLT_FR,               LINKTYPE_FRELAY },
 242 #endif
 243         { DLT_ATM_RFC1483,      LINKTYPE_ATM_RFC1483 },
 244         { DLT_RAW,              LINKTYPE_RAW },
 245         { DLT_SLIP_BSDOS,       LINKTYPE_SLIP_BSDOS },
 246         { DLT_PPP_BSDOS,        LINKTYPE_PPP_BSDOS },
 247
 248         /* BSD/OS Cisco HDLC */
 249         { DLT_C_HDLC,           LINKTYPE_C_HDLC },
 250
 251         /*
 252          * These DLT_* codes are not on all platforms, but, so far,
 253          * there don't appear to be any platforms that define
 254          * other codes with those values; we map them to
 255          * different LINKTYPE_* values anyway, just in case.
 256          */
 257
 258         /* Linux ATM Classical IP */
 259         { DLT_ATM_CLIP,         LINKTYPE_ATM_CLIP },
 260
 261         /* NetBSD sync/async serial PPP (or Cisco HDLC) */
 262         { DLT_PPP_SERIAL,       LINKTYPE_PPP_HDLC },
 263
 264         /* NetBSD PPP over Ethernet */
 265         { DLT_PPP_ETHER,        LINKTYPE_PPP_ETHER },
 266
 267         /* IEEE 802.11 wireless */
 268         { DLT_IEEE802_11,       LINKTYPE_IEEE802_11 },
 269
 270         /* Frame Relay */
 271         { DLT_FRELAY,           LINKTYPE_FRELAY },
 272
 273         /* OpenBSD loopback */
 274         { DLT_LOOP,             LINKTYPE_LOOP },
 275
 276         /* Linux cooked socket capture */
 277         { DLT_LINUX_SLL,        LINKTYPE_LINUX_SLL },
 278
 279         /* Apple LocalTalk hardware */
 280         { DLT_LTALK,            LINKTYPE_LTALK },
 281
 282         /* Acorn Econet */
 283         { DLT_ECONET,           LINKTYPE_ECONET },
 284
 285         /* OpenBSD DLT_PFLOG */
 286         { DLT_PFLOG,            LINKTYPE_PFLOG },
 287
 288         /* For Cisco-internal use */
 289         { DLT_CISCO_IOS,        LINKTYPE_CISCO_IOS },
 290
 291         /* Prism II monitor-mode header plus 802.11 header */
 292         { DLT_PRISM_HEADER,     LINKTYPE_PRISM_HEADER },
 293
 294         /* FreeBSD Aironet driver stuff */
 295         { DLT_AIRONET_HEADER,   LINKTYPE_AIRONET_HEADER },
 296
 297         /* Siemens HiPath HDLC */
 298         { DLT_HHDLC,            LINKTYPE_HHDLC },
 299
 300         /* RFC 2625 IP-over-Fibre Channel */
 301         { DLT_IP_OVER_FC,       LINKTYPE_IP_OVER_FC },
 302
 303         /* Solaris+SunATM */
 304         { DLT_SUNATM,           LINKTYPE_SUNATM },
 305
 306         /* RapidIO */
 307         { DLT_RIO,              LINKTYPE_RIO },
 308
 309         /* PCI Express */
 310         { DLT_PCI_EXP,          LINKTYPE_PCI_EXP },
 311
 312         /* Xilinx Aurora link layer */
 313         { DLT_AURORA,           LINKTYPE_AURORA },
 314
 315         /* 802.11 plus WLAN header */
 316         { DLT_IEEE802_11_RADIO, LINKTYPE_IEEE802_11_RADIO },
 317
 318         /* Tazmen Sniffer Protocol */
 319         { DLT_TZSP,             LINKTYPE_TZSP },
 320
 321         /* Arcnet with Linux-style link-layer headers */
 322         { DLT_ARCNET_LINUX,     LINKTYPE_ARCNET_LINUX },
 323
 324         /* Juniper-internal chassis encapsulation */
 325         { DLT_JUNIPER_MLPPP,    LINKTYPE_JUNIPER_MLPPP },
 326         { DLT_JUNIPER_MLFR,     LINKTYPE_JUNIPER_MLFR },
 327         { DLT_JUNIPER_ES,       LINKTYPE_JUNIPER_ES },
 328         { DLT_JUNIPER_GGSN,     LINKTYPE_JUNIPER_GGSN },
 329         { DLT_JUNIPER_MFR,      LINKTYPE_JUNIPER_MFR },
 330         { DLT_JUNIPER_ATM2,     LINKTYPE_JUNIPER_ATM2 },
 331         { DLT_JUNIPER_SERVICES, LINKTYPE_JUNIPER_SERVICES },
 332         { DLT_JUNIPER_ATM1,     LINKTYPE_JUNIPER_ATM1 },
 333
 334         /* Apple IP-over-IEEE 1394 cooked header */
 335         { DLT_APPLE_IP_OVER_IEEE1394, LINKTYPE_APPLE_IP_OVER_IEEE1394 },
 336
 337         /* DOCSIS MAC frames */
 338         { DLT_DOCSIS,           LINKTYPE_DOCSIS },
 339
 340         /* IrDA IrLAP packets + Linux-cooked header */
 341         { DLT_LINUX_IRDA,       LINKTYPE_LINUX_IRDA },
 342
 343         /*
 344          * Any platform that defines additional DLT_* codes should:
 345          *
 346          *      request a LINKTYPE_* code and value from tcpdump.org,
 347          *      as per the above;
 348          *
 349          *      add, in their version of libpcap, an entry to map
 350          *      those DLT_* codes to the corresponding LINKTYPE_*
 351          *      code;
 352          *
 353          *      redefine, in their "net/bpf.h", any DLT_* values
 354          *      that collide with the values used by their additional
 355          *      DLT_* codes, to remove those collisions (but without
 356          *      making them collide with any of the LINKTYPE_*
 357          *      values equal to 50 or above; they should also avoid
 358          *      defining DLT_* values that collide with those
 359          *      LINKTYPE_* values, either).
 360          */
 361         { -1,                   -1 }
 362 };
 363
 364 static int
 365 dlt_to_linktype(int dlt)
 366 {
 367         int i;
 368
 369         for (i = 0; map[i].dlt != -1; i++) {
 370                 if (map[i].dlt == dlt)
 371                         return (map[i].linktype);
 372         }
 373
 374         /*
 375          * If we don't have a mapping for this DLT_ code, return an
 376          * error; that means that the table above needs to have an
 377          * entry added.
 378          */
 379         return (-1);
 380 }
 381
 382 static int
 383 linktype_to_dlt(int linktype)
 384 {
 385         int i;
 386
 387         for (i = 0; map[i].linktype != -1; i++) {
 388                 if (map[i].linktype == linktype)
 389                         return (map[i].dlt);
 390         }
 391
 392         /*
 393          * If we don't have an entry for this link type, return
 394          * the link type value; it may be a DLT_ value from an
 395          * older version of libpcap.
 396          */
 397         return linktype;
 398 }
 399
 400 static int
 401 sf_write_header(FILE *fp, int linktype, int thiszone, int snaplen)
 402 {
 403         struct pcap_file_header hdr;
 404
 405         hdr.magic = TCPDUMP_MAGIC;
 406         hdr.version_major = PCAP_VERSION_MAJOR;
 407         hdr.version_minor = PCAP_VERSION_MINOR;
 408
 409         hdr.thiszone = thiszone;
 410         hdr.snaplen = snaplen;
 411         hdr.sigfigs = 0;
 412         hdr.linktype = linktype;
 413
 414         if (fwrite((char *)&hdr, sizeof(hdr), 1, fp) != 1)
 415                 return (-1);
 416
 417         return (0);
 418 }
 419
 420 static void
 421 swap_hdr(struct pcap_file_header *hp)
 422 {
 423         hp->version_major = SWAPSHORT(hp->version_major);
 424         hp->version_minor = SWAPSHORT(hp->version_minor);
 425         hp->thiszone = SWAPLONG(hp->thiszone);
 426         hp->sigfigs = SWAPLONG(hp->sigfigs);
 427         hp->snaplen = SWAPLONG(hp->snaplen);
 428         hp->linktype = SWAPLONG(hp->linktype);
 429 }
 430
 431 static int
 432 sf_getnonblock(pcap_t *p, char *errbuf)
 433 {
 434         /*
 435          * This is a savefile, not a live capture file, so never say
 436          * it's in non-blocking mode.
 437          */
 438         return (0);
 439 }
 440
 441 static int
 442 sf_setnonblock(pcap_t *p, int nonblock, char *errbuf)
 443 {
 444         /*
 445          * This is a savefile, not a live capture file, so ignore
 446          * requests to put it in non-blocking mode.
 447          */
 448         return (0);
 449 }
 450
 451 static int
 452 sf_stats(pcap_t *p, struct pcap_stat *ps)
 453 {
 454         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 455             "Statistics aren't available from savefiles");
 456         return (-1);
 457 }
 458
 459 static void
 460 sf_close(pcap_t *p)
 461 {
 462         if (p->sf.rfile != stdin)
 463                 (void)fclose(p->sf.rfile);
 464         if (p->sf.base != NULL)
 465                 free(p->sf.base);
 466 }
 467
 468 pcap_t *
 469 pcap_open_offline(const char *fname, char *errbuf)
 470 {
 471         register pcap_t *p;
 472         register FILE *fp;
 473         struct pcap_file_header hdr;
 474         bpf_u_int32 magic;
 475         int linklen;
 476
 477         p = (pcap_t *)malloc(sizeof(*p));
 478         if (p == NULL) {
 479                 strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
 480                 return (NULL);
 481         }
 482
 483         memset((char *)p, 0, sizeof(*p));
 484
 485         if (fname[0] == '-' && fname[1] == '\0')
 486                 fp = stdin;
 487         else {
 488 #ifndef WIN32
 489                 fp = fopen(fname, "r");
 490 #else
 491                 fp = fopen(fname, "rb");
 492 #endif
 493                 if (fp == NULL) {
 494                         snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname,
 495                             pcap_strerror(errno));
 496                         goto bad;
 497                 }
 498         }
 499         if (fread((char *)&hdr, sizeof(hdr), 1, fp) != 1) {
 500                 snprintf(errbuf, PCAP_ERRBUF_SIZE, "fread: %s",
 501                     pcap_strerror(errno));
 502                 goto bad;
 503         }
 504         magic = hdr.magic;
 505         if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
 506                 magic = SWAPLONG(magic);
 507                 if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
 508                         snprintf(errbuf, PCAP_ERRBUF_SIZE,
 509                             "bad dump file format");
 510                         goto bad;
 511                 }
 512                 p->sf.swapped = 1;
 513                 swap_hdr(&hdr);
 514         }
 515         if (magic == PATCHED_TCPDUMP_MAGIC) {
 516                 /*
 517                  * XXX - the patch that's in some versions of libpcap
 518                  * changes the packet header but not the magic number;
 519                  * we'd have to use some hacks^H^H^H^H^Hheuristics to
 520                  * detect that.
 521                  */
 522                 p->sf.hdrsize = sizeof(struct pcap_sf_patched_pkthdr);
 523         } else
 524                 p->sf.hdrsize = sizeof(struct pcap_sf_pkthdr);
 525         if (hdr.version_major < PCAP_VERSION_MAJOR) {
 526                 snprintf(errbuf, PCAP_ERRBUF_SIZE, "archaic file format");
 527                 goto bad;
 528         }
 529         p->tzoff = hdr.thiszone;
 530         p->snapshot = hdr.snaplen;
 531         p->linktype = linktype_to_dlt(hdr.linktype);
 532         p->sf.rfile = fp;
 533 #ifndef WIN32
 534         p->bufsize = hdr.snaplen;
 535 #else
 536         /* Allocate the space for pcap_pkthdr as well. It will be used by pcap_read_ex */
 537         p->bufsize = hdr.snaplen+sizeof(struct pcap_pkthdr);
 538 #endif
 539
 540         /* Align link header as required for proper data alignment */
 541         /* XXX should handle all types */
 542         switch (p->linktype) {
 543
 544         case DLT_EN10MB:
 545                 linklen = 14;
 546                 break;
 547
 548         case DLT_FDDI:
 549                 linklen = 13 + 8;       /* fddi_header + llc */
 550                 break;
 551
 552         case DLT_NULL:
 553         default:
 554                 linklen = 0;
 555                 break;
 556         }
 557
 558         if (p->bufsize < 0)
 559                 p->bufsize = BPF_MAXBUFSIZE;
 560         p->sf.base = (u_char *)malloc(p->bufsize + BPF_ALIGNMENT);
 561         if (p->sf.base == NULL) {
 562                 strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
 563                 goto bad;
 564         }
 565         p->buffer = p->sf.base + BPF_ALIGNMENT - (linklen % BPF_ALIGNMENT);
 566         p->sf.version_major = hdr.version_major;
 567         p->sf.version_minor = hdr.version_minor;
 568 #ifdef PCAP_FDDIPAD
 569         /* XXX padding only needed for kernel fcode */
 570         pcap_fddipad = 0;
 571 #endif
 572
 573         /*
 574          * We interchanged the caplen and len fields at version 2.3,
 575          * in order to match the bpf header layout.  But unfortunately
 576          * some files were written with version 2.3 in their headers
 577          * but without the interchanged fields.
 578          *
 579          * In addition, DG/UX tcpdump writes out files with a version
 580          * number of 543.0, and with the caplen and len fields in the
 581          * pre-2.3 order.
 582          */
 583         switch (hdr.version_major) {
 584
 585         case 2:
 586                 if (hdr.version_minor < 3)
 587                         p->sf.lengths_swapped = SWAPPED;
 588                 else if (hdr.version_minor == 3)
 589                         p->sf.lengths_swapped = MAYBE_SWAPPED;
 590                 else
 591                         p->sf.lengths_swapped = NOT_SWAPPED;
 592                 break;
 593
 594         case 543:
 595                 p->sf.lengths_swapped = SWAPPED;
 596                 break;
 597
 598         default:
 599                 p->sf.lengths_swapped = NOT_SWAPPED;
 600                 break;
 601         }
 602
 603         p->read_op = pcap_offline_read;
 604         p->setfilter_op = install_bpf_program;
 605         p->set_datalink_op = NULL;      /* we don't support munging link-layer headers */
 606         p->getnonblock_op = sf_getnonblock;
 607         p->setnonblock_op = sf_setnonblock;
 608         p->stats_op = sf_stats;
 609         p->close_op = sf_close;
 610
 611         return (p);
 612  bad:
 613         if(fp)
 614                 fclose(fp);
 615         free(p);
 616         return (NULL);
 617 }
 618
 619 /*
 620  * Read sf_readfile and return the next packet.  Return the header in hdr
 621  * and the contents in buf.  Return 0 on success, SFERR_EOF if there were
 622  * no more packets, and SFERR_TRUNC if a partial packet was encountered.
 623  */
 624 static int
 625 sf_next_packet(pcap_t *p, struct pcap_pkthdr *hdr, u_char *buf, u_int buflen)
 626 {
 627         struct pcap_sf_patched_pkthdr sf_hdr;
 628         FILE *fp = p->sf.rfile;
 629         size_t amt_read;
 630         bpf_u_int32 t;
 631
 632         /*
 633          * Read the packet header; the structure we use as a buffer
 634          * is the longer structure for files generated by the patched
 635          * libpcap, but if the file has the magic number for an
 636          * unpatched libpcap we only read as many bytes as the regular
 637          * header has.
 638          */
 639         amt_read = fread(&sf_hdr, 1, p->sf.hdrsize, fp);
 640         if (amt_read != p->sf.hdrsize) {
 641                 if (ferror(fp)) {
 642                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 643                             "error reading dump file: %s",
 644                             pcap_strerror(errno));
 645                         return (-1);
 646                 } else {
 647                         if (amt_read != 0) {
 648                                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 649                                     "truncated dump file; tried to read %d header bytes, only got %lu",
 650                                     p->sf.hdrsize, (unsigned long)amt_read);
 651                                 return (-1);
 652                         }
 653                         /* EOF */
 654                         return (1);
 655                 }
 656         }
 657
 658         if (p->sf.swapped) {
 659                 /* these were written in opposite byte order */
 660                 hdr->caplen = SWAPLONG(sf_hdr.caplen);
 661                 hdr->len = SWAPLONG(sf_hdr.len);
 662                 hdr->ts.tv_sec = SWAPLONG(sf_hdr.ts.tv_sec);
 663                 hdr->ts.tv_usec = SWAPLONG(sf_hdr.ts.tv_usec);
 664         } else {
 665                 hdr->caplen = sf_hdr.caplen;
 666                 hdr->len = sf_hdr.len;
 667                 hdr->ts.tv_sec = sf_hdr.ts.tv_sec;
 668                 hdr->ts.tv_usec = sf_hdr.ts.tv_usec;
 669         }
 670         /* Swap the caplen and len fields, if necessary. */
 671         switch (p->sf.lengths_swapped) {
 672
 673         case NOT_SWAPPED:
 674                 break;
 675
 676         case MAYBE_SWAPPED:
 677                 if (hdr->caplen <= hdr->len) {
 678                         /*
 679                          * The captured length is <= the actual length,
 680                          * so presumably they weren't swapped.
 681                          */
 682                         break;
 683                 }
 684                 /* FALLTHROUGH */
 685
 686         case SWAPPED:
 687                 t = hdr->caplen;
 688                 hdr->caplen = hdr->len;
 689                 hdr->len = t;
 690                 break;
 691         }
 692
 693         if (hdr->caplen > buflen) {
 694                 /*
 695                  * This can happen due to Solaris 2.3 systems tripping
 696                  * over the BUFMOD problem and not setting the snapshot
 697                  * correctly in the savefile header.  If the caplen isn't
 698                  * grossly wrong, try to salvage.
 699                  */
 700                 static u_char *tp = NULL;
 701                 static size_t tsize = 0;
 702
 703                 if (hdr->caplen > 65535) {
 704                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 705                             "bogus savefile header");
 706                         return (-1);
 707                 }
 708
 709                 if (tsize < hdr->caplen) {
 710                         tsize = ((hdr->caplen + 1023) / 1024) * 1024;
 711                         if (tp != NULL)
 712                                 free((u_char *)tp);
 713                         tp = (u_char *)malloc(tsize);
 714                         if (tp == NULL) {
 715                                 tsize = 0;
 716                                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 717                                     "BUFMOD hack malloc");
 718                                 return (-1);
 719                         }
 720                 }
 721                 amt_read = fread((char *)tp, 1, hdr->caplen, fp);
 722                 if (amt_read != hdr->caplen) {
 723                         if (ferror(fp)) {
 724                                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 725                                     "error reading dump file: %s",
 726                                     pcap_strerror(errno));
 727                         } else {
 728                                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 729                                     "truncated dump file; tried to read %u captured bytes, only got %lu",
 730                                     hdr->caplen, (unsigned long)amt_read);
 731                         }
 732                         return (-1);
 733                 }
 734                 /*
 735                  * We can only keep up to buflen bytes.  Since caplen > buflen
 736                  * is exactly how we got here, we know we can only keep the
 737                  * first buflen bytes and must drop the remainder.  Adjust
 738                  * caplen accordingly, so we don't get confused later as
 739                  * to how many bytes we have to play with.
 740                  */
 741                 hdr->caplen = buflen;
 742                 memcpy((char *)buf, (char *)tp, buflen);
 743
 744         } else {
 745                 /* read the packet itself */
 746                 amt_read = fread((char *)buf, 1, hdr->caplen, fp);
 747                 if (amt_read != hdr->caplen) {
 748                         if (ferror(fp)) {
 749                                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 750                                     "error reading dump file: %s",
 751                                     pcap_strerror(errno));
 752                         } else {
 753                                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 754                                     "truncated dump file; tried to read %u captured bytes, only got %lu",
 755                                     hdr->caplen, (unsigned long)amt_read);
 756                         }
 757                         return (-1);
 758                 }
 759         }
 760         return (0);
 761 }
 762
 763 /*
 764  * Print out packets stored in the file initialized by sf_read_init().
 765  * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
 766  */
 767 int
 768 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 769 {
 770         struct bpf_insn *fcode = p->fcode.bf_insns;
 771         int status = 0;
 772         int n = 0;
 773
 774         while (status == 0) {
 775                 struct pcap_pkthdr h;
 776
 777                 /*
 778                  * Has "pcap_breakloop()" been called?
 779                  * If so, return immediately - if we haven't read any
 780                  * packets, clear the flag and return -2 to indicate
 781                  * that we were told to break out of the loop, otherwise
 782                  * leave the flag set, so that the *next* call will break
 783                  * out of the loop without having read any packets, and
 784                  * return the number of packets we've processed so far.
 785                  */
 786                 if (p->break_loop) {
 787                         if (n == 0) {
 788                                 p->break_loop = 0;
 789                                 return (-2);
 790                         } else
 791                                 return (n);
 792                 }
 793
 794                 status = sf_next_packet(p, &h, p->buffer, p->bufsize);
 795                 if (status) {
 796                         if (status == 1)
 797                                 return (0);
 798                         return (status);
 799                 }
 800
 801                 if (fcode == NULL ||
 802                     bpf_filter(fcode, p->buffer, h.len, h.caplen)) {
 803                         (*callback)(user, &h, p->buffer);
 804                         if (++n >= cnt && cnt > 0)
 805                                 break;
 806                 }
 807         }
 808         /*XXX this breaks semantics tcpslice expects */
 809         return (n);
 810 }
 811
 812 /*
 813  * Output a packet to the initialized dump file.
 814  */
 815 void
 816 pcap_dump(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 817 {
 818         register FILE *f;
 819         struct pcap_sf_pkthdr sf_hdr;
 820
 821         f = (FILE *)user;
 822         sf_hdr.ts.tv_sec  = h->ts.tv_sec;
 823         sf_hdr.ts.tv_usec = h->ts.tv_usec;
 824         sf_hdr.caplen     = h->caplen;
 825         sf_hdr.len        = h->len;
 826         /* XXX we should check the return status */
 827         (void)fwrite(&sf_hdr, sizeof(sf_hdr), 1, f);
 828         (void)fwrite((char *)sp, h->caplen, 1, f);
 829 }
 830
 831 /*
 832  * Initialize so that sf_write() will output to the file named 'fname'.
 833  */
 834 pcap_dumper_t *
 835 pcap_dump_open(pcap_t *p, const char *fname)
 836 {
 837         FILE *f;
 838         int linktype;
 839
 840         linktype = dlt_to_linktype(p->linktype);
 841         if (linktype == -1) {
 842                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 843                     "%s: link-layer type %d isn't supported in savefiles",
 844                     fname, linktype);
 845                 return (NULL);
 846         }
 847
 848         if (fname[0] == '-' && fname[1] == '\0') {
 849                 f = stdout;
 850 #ifdef WIN32
 851                 _setmode(_fileno(f), _O_BINARY);
 852 #endif
 853         } else {
 854 #ifndef WIN32
 855                 f = fopen(fname, "w");
 856 #else
 857                 f = fopen(fname, "wb");
 858                 setbuf(f, NULL);        /* XXX - why? */
 859 #endif
 860                 if (f == NULL) {
 861                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
 862                             fname, pcap_strerror(errno));
 863                         return (NULL);
 864                 }
 865         }
 866         (void)sf_write_header(f, linktype, p->tzoff, p->snapshot);
 867         return ((pcap_dumper_t *)f);
 868 }
 869
 870 FILE *
 871 pcap_dump_file(pcap_dumper_t *p)
 872 {
 873         return ((FILE *)p);
 874 }
 875
 876 int
 877 pcap_dump_flush(pcap_dumper_t *p)
 878 {
 879
 880         if (fflush((FILE *)p) == EOF)
 881                 return (-1);
 882         else
 883                 return (0);
 884 }
 885
 886 void
 887 pcap_dump_close(pcap_dumper_t *p)
 888 {
 889
 890 #ifdef notyet
 891         if (ferror((FILE *)p))
 892                 return-an-error;
 893         /* XXX should check return from fclose() too */
 894 #endif
 895         (void)fclose((FILE *)p);
 896 }