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[] =
  33     "@(#) $Header: /tcpdump/master/libpcap/savefile.c,v 1.74 2003-01-21 04:39:05 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 packets are always written in network byte order.
  61  *
  62  * ntoh[ls] aren't sufficient because we might need to swap on a big-endian
  63  * machine (if the file was written in little-end order).
  64  */
  65 #define SWAPLONG(y) \
  66 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
  67 #define SWAPSHORT(y) \
  68         ( (((y)&0xff)<<8) | ((u_short)((y)&0xff00)>>8) )
  69
  70 #define SFERR_TRUNC             1
  71 #define SFERR_BADVERSION        2
  72 #define SFERR_BADF              3
  73 #define SFERR_EOF               4 /* not really an error, just a status */
  74
  75 /*
  76  * We don't write DLT_* values to the capture file header, because
  77  * they're not the same on all platforms.
  78  *
  79  * Unfortunately, the various flavors of BSD have not always used the same
  80  * numerical values for the same data types, and various patches to
  81  * libpcap for non-BSD OSes have added their own DLT_* codes for link
  82  * layer encapsulation types seen on those OSes, and those codes have had,
  83  * in some cases, values that were also used, on other platforms, for other
  84  * link layer encapsulation types.
  85  *
  86  * This means that capture files of a type whose numerical DLT_* code
  87  * means different things on different BSDs, or with different versions
  88  * of libpcap, can't always be read on systems other than those like
  89  * the one running on the machine on which the capture was made.
  90  *
  91  * Instead, we define here a set of LINKTYPE_* codes, and map DLT_* codes
  92  * to LINKTYPE_* codes when writing a savefile header, and map LINKTYPE_*
  93  * codes to DLT_* codes when reading a savefile header.
  94  *
  95  * For those DLT_* codes that have, as far as we know, the same values on
  96  * all platforms (DLT_NULL through DLT_FDDI), we define LINKTYPE_xxx as
  97  * DLT_xxx; that way, captures of those types can still be read by
  98  * versions of libpcap that map LINKTYPE_* values to DLT_* values, and
  99  * captures of those types written by versions of libpcap that map DLT_
 100  * values to LINKTYPE_ values can still be read by older versions
 101  * of libpcap.
 102  *
 103  * The other LINKTYPE_* codes are given values starting at 100, in the
 104  * hopes that no DLT_* code will be given one of those values.
 105  *
 106  * In order to ensure that a given LINKTYPE_* code's value will refer to
 107  * the same encapsulation type on all platforms, you should not allocate
 108  * a new LINKTYPE_* value without consulting "tcpdump-workers@tcpdump.org".
 109  * The tcpdump developers will allocate a value for you, and will not
 110  * subsequently allocate it to anybody else; that value will be added to
 111  * the "pcap.h" in the tcpdump.org CVS repository, so that a future
 112  * libpcap release will include it.
 113  *
 114  * You should, if possible, also contribute patches to libpcap and tcpdump
 115  * to handle the new encapsulation type, so that they can also be checked
 116  * into the tcpdump.org CVS repository and so that they will appear in
 117  * future libpcap and tcpdump releases.
 118  */
 119 #define LINKTYPE_NULL           DLT_NULL
 120 #define LINKTYPE_ETHERNET       DLT_EN10MB      /* also for 100Mb and up */
 121 #define LINKTYPE_EXP_ETHERNET   DLT_EN3MB       /* 3Mb experimental Ethernet */
 122 #define LINKTYPE_AX25           DLT_AX25
 123 #define LINKTYPE_PRONET         DLT_PRONET
 124 #define LINKTYPE_CHAOS          DLT_CHAOS
 125 #define LINKTYPE_TOKEN_RING     DLT_IEEE802     /* DLT_IEEE802 is used for Token Ring */
 126 #define LINKTYPE_ARCNET         DLT_ARCNET      /* NetBSD-style headers */
 127 #define LINKTYPE_SLIP           DLT_SLIP
 128 #define LINKTYPE_PPP            DLT_PPP
 129 #define LINKTYPE_FDDI           DLT_FDDI
 130
 131 /*
 132  * LINKTYPE_PPP is for use when there might, or might not, be an RFC 1662
 133  * PPP in HDLC-like framing header (with 0xff 0x03 before the PPP protocol
 134  * field) at the beginning of the packet.
 135  *
 136  * This is for use when there is always such a header; the address field
 137  * might be 0xff, for regular PPP, or it might be an address field for Cisco
 138  * point-to-point with HDLC framing as per section 4.3.1 of RFC 1547 ("Cisco
 139  * HDLC").  This is, for example, what you get with NetBSD's DLT_PPP_SERIAL.
 140  *
 141  * We give it the same value as NetBSD's DLT_PPP_SERIAL, in the hopes that
 142  * nobody else will choose a DLT_ value of 50, and so that DLT_PPP_SERIAL
 143  * captures will be written out with a link type that NetBSD's tcpdump
 144  * can read.
 145  */
 146 #define LINKTYPE_PPP_HDLC       50              /* PPP in HDLC-like framing */
 147
 148 #define LINKTYPE_PPP_ETHER      51              /* NetBSD PPP-over-Ethernet */
 149
 150 #define LINKTYPE_ATM_RFC1483    100             /* LLC/SNAP-encapsulated ATM */
 151 #define LINKTYPE_RAW            101             /* raw IP */
 152 #define LINKTYPE_SLIP_BSDOS     102             /* BSD/OS SLIP BPF header */
 153 #define LINKTYPE_PPP_BSDOS      103             /* BSD/OS PPP BPF header */
 154 #define LINKTYPE_C_HDLC         104             /* Cisco HDLC */
 155 #define LINKTYPE_IEEE802_11     105             /* IEEE 802.11 (wireless) */
 156 #define LINKTYPE_ATM_CLIP       106             /* Linux Classical IP over ATM */
 157 #define LINKTYPE_FRELAY         107             /* Frame Relay */
 158 #define LINKTYPE_LOOP           108             /* OpenBSD loopback */
 159
 160 #define LINKTYPE_LINUX_SLL      113             /* Linux cooked socket capture */
 161 #define LINKTYPE_LTALK          114             /* Apple LocalTalk hardware */
 162 #define LINKTYPE_ECONET         115             /* Acorn Econet */
 163
 164 #define LINKTYPE_CISCO_IOS      118             /* For Cisco-internal use */
 165 #define LINKTYPE_PRISM_HEADER   119             /* 802.11+Prism II monitor mode */
 166 #define LINKTYPE_AIRONET_HEADER 120             /* FreeBSD Aironet driver stuff */
 167 #define LINKTYPE_IP_OVER_FC     122             /* RFC 2625 IP-over-Fibre Channel */
 168 #define LINKTYPE_SUNATM         123             /* Solaris+SunATM */
 169
 170 #define LINKTYPE_IEEE802_11_RADIO 127           /* 802.11 plus WLAN header */
 171
 172 #define LINKTYPE_TZSP           128             /* Tazmen Sniffer Protocol */
 173
 174 #define LINKTYPE_ARCNET_LINUX   129             /* Linux-style headers */
 175
 176 /*
 177  * These types are reserved for future use.
 178  */
 179 #define LINKTYPE_ENC            109             /* OpenBSD IPSEC enc */
 180 #define LINKTYPE_LANE8023       110             /* ATM LANE + 802.3 */
 181 #define LINKTYPE_HIPPI          111             /* NetBSD HIPPI */
 182 #define LINKTYPE_HDLC           112             /* NetBSD HDLC framing */
 183 #define LINKTYPE_IPFILTER       116             /* IP Filter capture files */
 184 #define LINKTYPE_PFLOG          117             /* OpenBSD DLT_PFLOG */
 185 #define LINKTYPE_HHDLC          121             /* Siemens HiPath HDLC */
 186 #define LINKTYPE_RIO            124             /* RapidIO */
 187 #define LINKTYPE_PCI_EXP        125             /* PCI Express */
 188 #define LINKTYPE_AURORA         126             /* Xilinx Aurora link layer */
 189
 190 static struct linktype_map {
 191         int     dlt;
 192         int     linktype;
 193 } map[] = {
 194         /*
 195          * These DLT_* codes have LINKTYPE_* codes with values identical
 196          * to the values of the corresponding DLT_* code.
 197          */
 198         { DLT_NULL,             LINKTYPE_NULL },
 199         { DLT_EN10MB,           LINKTYPE_ETHERNET },
 200         { DLT_EN3MB,            LINKTYPE_EXP_ETHERNET },
 201         { DLT_AX25,             LINKTYPE_AX25 },
 202         { DLT_PRONET,           LINKTYPE_PRONET },
 203         { DLT_CHAOS,            LINKTYPE_CHAOS },
 204         { DLT_IEEE802,          LINKTYPE_TOKEN_RING },
 205         { DLT_ARCNET,           LINKTYPE_ARCNET },
 206         { DLT_SLIP,             LINKTYPE_SLIP },
 207         { DLT_PPP,              LINKTYPE_PPP },
 208         { DLT_FDDI,             LINKTYPE_FDDI },
 209
 210         /*
 211          * These DLT_* codes have different values on different
 212          * platforms; we map them to LINKTYPE_* codes that
 213          * have values that should never be equal to any DLT_*
 214          * code.
 215          */
 216 #ifdef DLT_FR
 217         /* BSD/OS Frame Relay */
 218         { DLT_FR,               LINKTYPE_FRELAY },
 219 #endif
 220         { DLT_ATM_RFC1483,      LINKTYPE_ATM_RFC1483 },
 221         { DLT_RAW,              LINKTYPE_RAW },
 222         { DLT_SLIP_BSDOS,       LINKTYPE_SLIP_BSDOS },
 223         { DLT_PPP_BSDOS,        LINKTYPE_PPP_BSDOS },
 224
 225         /* BSD/OS Cisco HDLC */
 226         { DLT_C_HDLC,           LINKTYPE_C_HDLC },
 227
 228         /*
 229          * These DLT_* codes are not on all platforms, but, so far,
 230          * there don't appear to be any platforms that define
 231          * other codes with those values; we map them to
 232          * different LINKTYPE_* values anyway, just in case.
 233          */
 234
 235         /* Linux ATM Classical IP */
 236         { DLT_ATM_CLIP,         LINKTYPE_ATM_CLIP },
 237
 238         /* NetBSD sync/async serial PPP (or Cisco HDLC) */
 239         { DLT_PPP_SERIAL,       LINKTYPE_PPP_HDLC },
 240
 241         /* NetBSD PPP over Ethernet */
 242         { DLT_PPP_ETHER,        LINKTYPE_PPP_ETHER },
 243
 244         /* IEEE 802.11 wireless */
 245         { DLT_IEEE802_11,       LINKTYPE_IEEE802_11 },
 246
 247         /* Frame Relay */
 248         { DLT_FRELAY,           LINKTYPE_FRELAY },
 249
 250         /* OpenBSD loopback */
 251         { DLT_LOOP,             LINKTYPE_LOOP },
 252
 253         /* Linux cooked socket capture */
 254         { DLT_LINUX_SLL,        LINKTYPE_LINUX_SLL },
 255
 256         /* Apple LocalTalk hardware */
 257         { DLT_LTALK,            LINKTYPE_LTALK },
 258
 259         /* Acorn Econet */
 260         { DLT_ECONET,           LINKTYPE_ECONET },
 261
 262         /* For Cisco-internal use */
 263         { DLT_CISCO_IOS,        LINKTYPE_CISCO_IOS },
 264
 265         /* Prism II monitor-mode header plus 802.11 header */
 266         { DLT_PRISM_HEADER,     LINKTYPE_PRISM_HEADER },
 267
 268         /* FreeBSD Aironet driver stuff */
 269         { DLT_AIRONET_HEADER,   LINKTYPE_AIRONET_HEADER },
 270
 271         /* Siemens HiPath HDLC */
 272         { DLT_HHDLC,            LINKTYPE_HHDLC },
 273
 274         /* RFC 2625 IP-over-Fibre Channel */
 275         { DLT_IP_OVER_FC,       LINKTYPE_IP_OVER_FC },
 276
 277         /* Solaris+SunATM */
 278         { DLT_SUNATM,           LINKTYPE_SUNATM },
 279
 280         /* RapidIO */
 281         { DLT_RIO,              LINKTYPE_RIO },
 282
 283         /* PCI Express */
 284         { DLT_PCI_EXP,          LINKTYPE_PCI_EXP },
 285
 286         /* Xilinx Aurora link layer */
 287         { DLT_AURORA,           LINKTYPE_AURORA },
 288
 289         /* 802.11 plus WLAN header */
 290         { DLT_IEEE802_11_RADIO, LINKTYPE_IEEE802_11_RADIO },
 291
 292         /* Tazmen Sniffer Protocol */
 293         { DLT_TZSP,             LINKTYPE_TZSP },
 294
 295         /* Arcnet with Linux-style link-layer headers */
 296         { DLT_ARCNET_LINUX,     LINKTYPE_ARCNET_LINUX },
 297
 298         /*
 299          * Any platform that defines additional DLT_* codes should:
 300          *
 301          *      request a LINKTYPE_* code and value from tcpdump.org,
 302          *      as per the above;
 303          *
 304          *      add, in their version of libpcap, an entry to map
 305          *      those DLT_* codes to the corresponding LINKTYPE_*
 306          *      code;
 307          *
 308          *      redefine, in their "net/bpf.h", any DLT_* values
 309          *      that collide with the values used by their additional
 310          *      DLT_* codes, to remove those collisions (but without
 311          *      making them collide with any of the LINKTYPE_*
 312          *      values equal to 50 or above; they should also avoid
 313          *      defining DLT_* values that collide with those
 314          *      LINKTYPE_* values, either).
 315          */
 316         { -1,                   -1 }
 317 };
 318
 319 static int
 320 dlt_to_linktype(int dlt)
 321 {
 322         int i;
 323
 324         for (i = 0; map[i].dlt != -1; i++) {
 325                 if (map[i].dlt == dlt)
 326                         return (map[i].linktype);
 327         }
 328
 329         /*
 330          * If we don't have a mapping for this DLT_ code, return an
 331          * error; that means that the table above needs to have an
 332          * entry added.
 333          */
 334         return (-1);
 335 }
 336
 337 static int
 338 linktype_to_dlt(int linktype)
 339 {
 340         int i;
 341
 342         for (i = 0; map[i].linktype != -1; i++) {
 343                 if (map[i].linktype == linktype)
 344                         return (map[i].dlt);
 345         }
 346
 347         /*
 348          * If we don't have an entry for this link type, return
 349          * the link type value; it may be a DLT_ value from an
 350          * older version of libpcap.
 351          */
 352         return linktype;
 353 }
 354
 355 static int
 356 sf_write_header(FILE *fp, int linktype, int thiszone, int snaplen)
 357 {
 358         struct pcap_file_header hdr;
 359
 360         hdr.magic = TCPDUMP_MAGIC;
 361         hdr.version_major = PCAP_VERSION_MAJOR;
 362         hdr.version_minor = PCAP_VERSION_MINOR;
 363
 364         hdr.thiszone = thiszone;
 365         hdr.snaplen = snaplen;
 366         hdr.sigfigs = 0;
 367         hdr.linktype = linktype;
 368
 369         if (fwrite((char *)&hdr, sizeof(hdr), 1, fp) != 1)
 370                 return (-1);
 371
 372         return (0);
 373 }
 374
 375 static void
 376 swap_hdr(struct pcap_file_header *hp)
 377 {
 378         hp->version_major = SWAPSHORT(hp->version_major);
 379         hp->version_minor = SWAPSHORT(hp->version_minor);
 380         hp->thiszone = SWAPLONG(hp->thiszone);
 381         hp->sigfigs = SWAPLONG(hp->sigfigs);
 382         hp->snaplen = SWAPLONG(hp->snaplen);
 383         hp->linktype = SWAPLONG(hp->linktype);
 384 }
 385
 386 pcap_t *
 387 pcap_open_offline(const char *fname, char *errbuf)
 388 {
 389         register pcap_t *p;
 390         register FILE *fp;
 391         struct pcap_file_header hdr;
 392         bpf_u_int32 magic;
 393         int linklen;
 394
 395         p = (pcap_t *)malloc(sizeof(*p));
 396         if (p == NULL) {
 397                 strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
 398                 return (NULL);
 399         }
 400
 401         memset((char *)p, 0, sizeof(*p));
 402         /*
 403          * Set this field so we don't close stdin in pcap_close!
 404          */
 405 #ifndef WIN32
 406         p->fd = -1;
 407 #else
 408         p->adapter = NULL;
 409 #endif
 410
 411         if (fname[0] == '-' && fname[1] == '\0')
 412                 fp = stdin;
 413         else {
 414 #ifndef WIN32
 415                 fp = fopen(fname, "r");
 416 #else
 417                 fp = fopen(fname, "rb");
 418 #endif
 419                 if (fp == NULL) {
 420                         snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname,
 421                             pcap_strerror(errno));
 422                         goto bad;
 423                 }
 424         }
 425         if (fread((char *)&hdr, sizeof(hdr), 1, fp) != 1) {
 426                 snprintf(errbuf, PCAP_ERRBUF_SIZE, "fread: %s",
 427                     pcap_strerror(errno));
 428                 goto bad;
 429         }
 430         magic = hdr.magic;
 431         if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
 432                 magic = SWAPLONG(magic);
 433                 if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
 434                         snprintf(errbuf, PCAP_ERRBUF_SIZE,
 435                             "bad dump file format");
 436                         goto bad;
 437                 }
 438                 p->sf.swapped = 1;
 439                 swap_hdr(&hdr);
 440         }
 441         if (magic == PATCHED_TCPDUMP_MAGIC) {
 442                 /*
 443                  * XXX - the patch that's in some versions of libpcap
 444                  * changes the packet header but not the magic number;
 445                  * we'd have to use some hacks^H^H^H^H^Hheuristics to
 446                  * detect that.
 447                  */
 448                 p->sf.hdrsize = sizeof(struct pcap_sf_patched_pkthdr);
 449         } else
 450                 p->sf.hdrsize = sizeof(struct pcap_sf_pkthdr);
 451         if (hdr.version_major < PCAP_VERSION_MAJOR) {
 452                 snprintf(errbuf, PCAP_ERRBUF_SIZE, "archaic file format");
 453                 goto bad;
 454         }
 455         p->tzoff = hdr.thiszone;
 456         p->snapshot = hdr.snaplen;
 457         p->linktype = linktype_to_dlt(hdr.linktype);
 458         p->sf.rfile = fp;
 459 #ifndef WIN32
 460         p->bufsize = hdr.snaplen;
 461 #else
 462         /* Allocate the space for pcap_pkthdr as well. It will be used by pcap_read_ex */
 463         p->bufsize = hdr.snaplen+sizeof(struct pcap_pkthdr);
 464 #endif
 465
 466         /* Align link header as required for proper data alignment */
 467         /* XXX should handle all types */
 468         switch (p->linktype) {
 469
 470         case DLT_EN10MB:
 471                 linklen = 14;
 472                 break;
 473
 474         case DLT_FDDI:
 475                 linklen = 13 + 8;       /* fddi_header + llc */
 476                 break;
 477
 478         case DLT_NULL:
 479         default:
 480                 linklen = 0;
 481                 break;
 482         }
 483
 484         if (p->bufsize < 0)
 485                 p->bufsize = BPF_MAXBUFSIZE;
 486         p->sf.base = (u_char *)malloc(p->bufsize + BPF_ALIGNMENT);
 487         if (p->sf.base == NULL) {
 488                 strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
 489                 goto bad;
 490         }
 491         p->buffer = p->sf.base + BPF_ALIGNMENT - (linklen % BPF_ALIGNMENT);
 492         p->sf.version_major = hdr.version_major;
 493         p->sf.version_minor = hdr.version_minor;
 494 #ifdef PCAP_FDDIPAD
 495         /* XXX padding only needed for kernel fcode */
 496         pcap_fddipad = 0;
 497 #endif
 498
 499         return (p);
 500  bad:
 501         if(fp)
 502                 fclose(fp);
 503         free(p);
 504         return (NULL);
 505 }
 506
 507 /*
 508  * Read sf_readfile and return the next packet.  Return the header in hdr
 509  * and the contents in buf.  Return 0 on success, SFERR_EOF if there were
 510  * no more packets, and SFERR_TRUNC if a partial packet was encountered.
 511  */
 512 #ifdef WIN32
 513 int
 514 #else
 515 static int
 516 #endif
 517 sf_next_packet(pcap_t *p, struct pcap_pkthdr *hdr, u_char *buf, int buflen)
 518 {
 519         struct pcap_sf_patched_pkthdr sf_hdr;
 520         FILE *fp = p->sf.rfile;
 521
 522         /*
 523          * Read the packet header; the structure we use as a buffer
 524          * is the longer structure for files generated by the patched
 525          * libpcap, but if the file has the magic number for an
 526          * unpatched libpcap we only read as many bytes as the regular
 527          * header has.
 528          */
 529         if (fread(&sf_hdr, p->sf.hdrsize, 1, fp) != 1) {
 530                 /* probably an EOF, though could be a truncated packet */
 531                 return (1);
 532         }
 533
 534         if (p->sf.swapped) {
 535                 /* these were written in opposite byte order */
 536                 hdr->caplen = SWAPLONG(sf_hdr.caplen);
 537                 hdr->len = SWAPLONG(sf_hdr.len);
 538                 hdr->ts.tv_sec = SWAPLONG(sf_hdr.ts.tv_sec);
 539                 hdr->ts.tv_usec = SWAPLONG(sf_hdr.ts.tv_usec);
 540         } else {
 541                 hdr->caplen = sf_hdr.caplen;
 542                 hdr->len = sf_hdr.len;
 543                 hdr->ts.tv_sec = sf_hdr.ts.tv_sec;
 544                 hdr->ts.tv_usec = sf_hdr.ts.tv_usec;
 545         }
 546         /*
 547          * We interchanged the caplen and len fields at version 2.3,
 548          * in order to match the bpf header layout.  But unfortunately
 549          * some files were written with version 2.3 in their headers
 550          * but without the interchanged fields.
 551          */
 552         if (p->sf.version_minor < 3 ||
 553             (p->sf.version_minor == 3 && hdr->caplen > hdr->len)) {
 554                 int t = hdr->caplen;
 555                 hdr->caplen = hdr->len;
 556                 hdr->len = t;
 557         }
 558
 559         if (hdr->caplen > buflen) {
 560                 /*
 561                  * This can happen due to Solaris 2.3 systems tripping
 562                  * over the BUFMOD problem and not setting the snapshot
 563                  * correctly in the savefile header.  If the caplen isn't
 564                  * grossly wrong, try to salvage.
 565                  */
 566                 static u_char *tp = NULL;
 567                 static int tsize = 0;
 568
 569                 if (hdr->caplen > 65535) {
 570                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 571                             "bogus savefile header");
 572                         return (-1);
 573                 }
 574
 575                 if (tsize < hdr->caplen) {
 576                         tsize = ((hdr->caplen + 1023) / 1024) * 1024;
 577                         if (tp != NULL)
 578                                 free((u_char *)tp);
 579                         tp = (u_char *)malloc(tsize);
 580                         if (tp == NULL) {
 581                                 tsize = 0;
 582                                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 583                                     "BUFMOD hack malloc");
 584                                 return (-1);
 585                         }
 586                 }
 587                 if (fread((char *)tp, hdr->caplen, 1, fp) != 1) {
 588                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 589                             "truncated dump file");
 590                         return (-1);
 591                 }
 592                 /*
 593                  * We can only keep up to buflen bytes.  Since caplen > buflen
 594                  * is exactly how we got here, we know we can only keep the
 595                  * first buflen bytes and must drop the remainder.  Adjust
 596                  * caplen accordingly, so we don't get confused later as
 597                  * to how many bytes we have to play with.
 598                  */
 599                 hdr->caplen = buflen;
 600                 memcpy((char *)buf, (char *)tp, buflen);
 601
 602         } else {
 603                 /* read the packet itself */
 604
 605                 if (fread((char *)buf, hdr->caplen, 1, fp) != 1) {
 606                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 607                             "truncated dump file");
 608                         return (-1);
 609                 }
 610         }
 611         return (0);
 612 }
 613
 614 /*
 615  * Print out packets stored in the file initialized by sf_read_init().
 616  * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
 617  */
 618 int
 619 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 620 {
 621         struct bpf_insn *fcode = p->fcode.bf_insns;
 622         int status = 0;
 623         int n = 0;
 624
 625         while (status == 0) {
 626                 struct pcap_pkthdr h;
 627
 628                 status = sf_next_packet(p, &h, p->buffer, p->bufsize);
 629                 if (status) {
 630                         if (status == 1)
 631                                 return (0);
 632                         return (status);
 633                 }
 634
 635                 if (fcode == NULL ||
 636                     bpf_filter(fcode, p->buffer, h.len, h.caplen)) {
 637                         (*callback)(user, &h, p->buffer);
 638                         if (++n >= cnt && cnt > 0)
 639                                 break;
 640                 }
 641         }
 642         /*XXX this breaks semantics tcpslice expects */
 643         return (n);
 644 }
 645
 646 /*
 647  * Output a packet to the initialized dump file.
 648  */
 649 void
 650 pcap_dump(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 651 {
 652         register FILE *f;
 653         struct pcap_sf_pkthdr sf_hdr;
 654
 655         f = (FILE *)user;
 656         sf_hdr.ts.tv_sec  = h->ts.tv_sec;
 657         sf_hdr.ts.tv_usec = h->ts.tv_usec;
 658         sf_hdr.caplen     = h->caplen;
 659         sf_hdr.len        = h->len;
 660         /* XXX we should check the return status */
 661         (void)fwrite(&sf_hdr, sizeof(sf_hdr), 1, f);
 662         (void)fwrite((char *)sp, h->caplen, 1, f);
 663 }
 664
 665 /*
 666  * Initialize so that sf_write() will output to the file named 'fname'.
 667  */
 668 pcap_dumper_t *
 669 pcap_dump_open(pcap_t *p, const char *fname)
 670 {
 671         FILE *f;
 672         int linktype;
 673
 674         linktype = dlt_to_linktype(p->linktype);
 675         if (linktype == -1) {
 676                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 677                     "%s: link-layer type %d isn't supported in savefiles",
 678                     fname, linktype);
 679                 return (NULL);
 680         }
 681
 682         if (fname[0] == '-' && fname[1] == '\0') {
 683                 f = stdout;
 684 #ifdef WIN32
 685                 _setmode(_fileno(f), _O_BINARY);
 686 #endif
 687         } else {
 688 #ifndef WIN32
 689                 f = fopen(fname, "w");
 690 #else
 691                 f = fopen(fname, "wb");
 692                 setbuf(f, NULL);        /* XXX - why? */
 693 #endif
 694                 if (f == NULL) {
 695                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
 696                             fname, pcap_strerror(errno));
 697                         return (NULL);
 698                 }
 699         }
 700         (void)sf_write_header(f, linktype, p->tzoff, p->snapshot);
 701         return ((pcap_dumper_t *)f);
 702 }
 703
 704 int
 705 pcap_dump_flush(pcap_dumper_t *p)
 706 {
 707
 708         if (fflush((FILE *)p) == EOF)
 709                 return (-1);
 710         else
 711                 return (0);
 712 }
 713
 714 void
 715 pcap_dump_close(pcap_dumper_t *p)
 716 {
 717
 718 #ifdef notyet
 719         if (ferror((FILE *)p))
 720                 return-an-error;
 721         /* XXX should check return from fclose() too */
 722 #endif
 723         (void)fclose((FILE *)p);
 724 }