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 1.80 2003-04-28 08:20:25 hannes 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      /* BSD-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 #define LINKTYPE_ENC            109             /* OpenBSD IPSEC enc */
 160
 161 #define LINKTYPE_LINUX_SLL      113             /* Linux cooked socket capture */
 162 #define LINKTYPE_LTALK          114             /* Apple LocalTalk hardware */
 163 #define LINKTYPE_ECONET         115             /* Acorn Econet */
 164
 165 #define LINKTYPE_PFLOG          117             /* OpenBSD DLT_PFLOG */
 166 #define LINKTYPE_CISCO_IOS      118             /* For Cisco-internal use */
 167 #define LINKTYPE_PRISM_HEADER   119             /* 802.11+Prism II monitor mode */
 168 #define LINKTYPE_AIRONET_HEADER 120             /* FreeBSD Aironet driver stuff */
 169 #define LINKTYPE_IP_OVER_FC     122             /* RFC 2625 IP-over-Fibre Channel */
 170 #define LINKTYPE_SUNATM         123             /* Solaris+SunATM */
 171
 172 #define LINKTYPE_IEEE802_11_RADIO 127           /* 802.11 plus WLAN header */
 173
 174 #define LINKTYPE_TZSP           128             /* Tazmen Sniffer Protocol */
 175
 176 #define LINKTYPE_ARCNET_LINUX   129             /* Linux-style headers */
 177
 178 #define LINKTYPE_JUNIPER_MLPPP  130             /* Juniper-internal chassis encapsulation */
 179 #define LINKTYPE_JUNIPER_MLFR   131
 180 #define LINKTYPE_JUNIPER_ES     132
 181 #define LINKTYPE_JUNIPER_GGSN   133
 182 #define LINKTYPE_JUNIPER_MFR    134
 183 #define LINKTYPE_JUNIPER_ATM2   135
 184 #define LINKTYPE_JUNIPER_SERVICES 136
 185 #define LINKTYPE_JUNIPER_ATM1   137
 186
 187 /*
 188  * These types are reserved for future use.
 189  */
 190 #define LINKTYPE_LANE8023       110             /* ATM LANE + 802.3 */
 191 #define LINKTYPE_HIPPI          111             /* NetBSD HIPPI */
 192 #define LINKTYPE_HDLC           112             /* NetBSD HDLC framing */
 193 #define LINKTYPE_IPFILTER       116             /* IP Filter capture files */
 194 #define LINKTYPE_HHDLC          121             /* Siemens HiPath HDLC */
 195 #define LINKTYPE_RIO            124             /* RapidIO */
 196 #define LINKTYPE_PCI_EXP        125             /* PCI Express */
 197 #define LINKTYPE_AURORA         126             /* Xilinx Aurora link layer */
 198
 199 static struct linktype_map {
 200         int     dlt;
 201         int     linktype;
 202 } map[] = {
 203         /*
 204          * These DLT_* codes have LINKTYPE_* codes with values identical
 205          * to the values of the corresponding DLT_* code.
 206          */
 207         { DLT_NULL,             LINKTYPE_NULL },
 208         { DLT_EN10MB,           LINKTYPE_ETHERNET },
 209         { DLT_EN3MB,            LINKTYPE_EXP_ETHERNET },
 210         { DLT_AX25,             LINKTYPE_AX25 },
 211         { DLT_PRONET,           LINKTYPE_PRONET },
 212         { DLT_CHAOS,            LINKTYPE_CHAOS },
 213         { DLT_IEEE802,          LINKTYPE_TOKEN_RING },
 214         { DLT_ARCNET,           LINKTYPE_ARCNET },
 215         { DLT_SLIP,             LINKTYPE_SLIP },
 216         { DLT_PPP,              LINKTYPE_PPP },
 217         { DLT_FDDI,             LINKTYPE_FDDI },
 218
 219         /*
 220          * These DLT_* codes have different values on different
 221          * platforms; we map them to LINKTYPE_* codes that
 222          * have values that should never be equal to any DLT_*
 223          * code.
 224          */
 225 #ifdef DLT_FR
 226         /* BSD/OS Frame Relay */
 227         { DLT_FR,               LINKTYPE_FRELAY },
 228 #endif
 229         { DLT_ATM_RFC1483,      LINKTYPE_ATM_RFC1483 },
 230         { DLT_RAW,              LINKTYPE_RAW },
 231         { DLT_SLIP_BSDOS,       LINKTYPE_SLIP_BSDOS },
 232         { DLT_PPP_BSDOS,        LINKTYPE_PPP_BSDOS },
 233
 234         /* BSD/OS Cisco HDLC */
 235         { DLT_C_HDLC,           LINKTYPE_C_HDLC },
 236
 237         /*
 238          * These DLT_* codes are not on all platforms, but, so far,
 239          * there don't appear to be any platforms that define
 240          * other codes with those values; we map them to
 241          * different LINKTYPE_* values anyway, just in case.
 242          */
 243
 244         /* Linux ATM Classical IP */
 245         { DLT_ATM_CLIP,         LINKTYPE_ATM_CLIP },
 246
 247         /* NetBSD sync/async serial PPP (or Cisco HDLC) */
 248         { DLT_PPP_SERIAL,       LINKTYPE_PPP_HDLC },
 249
 250         /* NetBSD PPP over Ethernet */
 251         { DLT_PPP_ETHER,        LINKTYPE_PPP_ETHER },
 252
 253         /* IEEE 802.11 wireless */
 254         { DLT_IEEE802_11,       LINKTYPE_IEEE802_11 },
 255
 256         /* Frame Relay */
 257         { DLT_FRELAY,           LINKTYPE_FRELAY },
 258
 259         /* OpenBSD loopback */
 260         { DLT_LOOP,             LINKTYPE_LOOP },
 261
 262         /* Linux cooked socket capture */
 263         { DLT_LINUX_SLL,        LINKTYPE_LINUX_SLL },
 264
 265         /* Apple LocalTalk hardware */
 266         { DLT_LTALK,            LINKTYPE_LTALK },
 267
 268         /* Acorn Econet */
 269         { DLT_ECONET,           LINKTYPE_ECONET },
 270
 271         /* OpenBSD DLT_PFLOG */
 272         { DLT_PFLOG,            LINKTYPE_PFLOG },
 273
 274         /* For Cisco-internal use */
 275         { DLT_CISCO_IOS,        LINKTYPE_CISCO_IOS },
 276
 277         /* Prism II monitor-mode header plus 802.11 header */
 278         { DLT_PRISM_HEADER,     LINKTYPE_PRISM_HEADER },
 279
 280         /* FreeBSD Aironet driver stuff */
 281         { DLT_AIRONET_HEADER,   LINKTYPE_AIRONET_HEADER },
 282
 283         /* Siemens HiPath HDLC */
 284         { DLT_HHDLC,            LINKTYPE_HHDLC },
 285
 286         /* RFC 2625 IP-over-Fibre Channel */
 287         { DLT_IP_OVER_FC,       LINKTYPE_IP_OVER_FC },
 288
 289         /* Solaris+SunATM */
 290         { DLT_SUNATM,           LINKTYPE_SUNATM },
 291
 292         /* RapidIO */
 293         { DLT_RIO,              LINKTYPE_RIO },
 294
 295         /* PCI Express */
 296         { DLT_PCI_EXP,          LINKTYPE_PCI_EXP },
 297
 298         /* Xilinx Aurora link layer */
 299         { DLT_AURORA,           LINKTYPE_AURORA },
 300
 301         /* 802.11 plus WLAN header */
 302         { DLT_IEEE802_11_RADIO, LINKTYPE_IEEE802_11_RADIO },
 303
 304         /* Tazmen Sniffer Protocol */
 305         { DLT_TZSP,             LINKTYPE_TZSP },
 306
 307         /* Arcnet with Linux-style link-layer headers */
 308         { DLT_ARCNET_LINUX,     LINKTYPE_ARCNET_LINUX },
 309
 310         /* Juniper-internal chassis encapsulation */
 311         { DLT_JUNIPER_MLPPP,    LINKTYPE_JUNIPER_MLPPP },
 312         { DLT_JUNIPER_MLFR,     LINKTYPE_JUNIPER_MLFR },
 313         { DLT_JUNIPER_ES,       LINKTYPE_JUNIPER_ES },
 314         { DLT_JUNIPER_GGSN,     LINKTYPE_JUNIPER_GGSN },
 315         { DLT_JUNIPER_MFR,      LINKTYPE_JUNIPER_MFR },
 316         { DLT_JUNIPER_ATM2,     LINKTYPE_JUNIPER_ATM2 },
 317         { DLT_JUNIPER_SERVICES, LINKTYPE_JUNIPER_SERVICES },
 318         { DLT_JUNIPER_ATM1,     LINKTYPE_JUNIPER_ATM1 },
 319
 320         /*
 321          * Any platform that defines additional DLT_* codes should:
 322          *
 323          *      request a LINKTYPE_* code and value from tcpdump.org,
 324          *      as per the above;
 325          *
 326          *      add, in their version of libpcap, an entry to map
 327          *      those DLT_* codes to the corresponding LINKTYPE_*
 328          *      code;
 329          *
 330          *      redefine, in their "net/bpf.h", any DLT_* values
 331          *      that collide with the values used by their additional
 332          *      DLT_* codes, to remove those collisions (but without
 333          *      making them collide with any of the LINKTYPE_*
 334          *      values equal to 50 or above; they should also avoid
 335          *      defining DLT_* values that collide with those
 336          *      LINKTYPE_* values, either).
 337          */
 338         { -1,                   -1 }
 339 };
 340
 341 static int
 342 dlt_to_linktype(int dlt)
 343 {
 344         int i;
 345
 346         for (i = 0; map[i].dlt != -1; i++) {
 347                 if (map[i].dlt == dlt)
 348                         return (map[i].linktype);
 349         }
 350
 351         /*
 352          * If we don't have a mapping for this DLT_ code, return an
 353          * error; that means that the table above needs to have an
 354          * entry added.
 355          */
 356         return (-1);
 357 }
 358
 359 static int
 360 linktype_to_dlt(int linktype)
 361 {
 362         int i;
 363
 364         for (i = 0; map[i].linktype != -1; i++) {
 365                 if (map[i].linktype == linktype)
 366                         return (map[i].dlt);
 367         }
 368
 369         /*
 370          * If we don't have an entry for this link type, return
 371          * the link type value; it may be a DLT_ value from an
 372          * older version of libpcap.
 373          */
 374         return linktype;
 375 }
 376
 377 static int
 378 sf_write_header(FILE *fp, int linktype, int thiszone, int snaplen)
 379 {
 380         struct pcap_file_header hdr;
 381
 382         hdr.magic = TCPDUMP_MAGIC;
 383         hdr.version_major = PCAP_VERSION_MAJOR;
 384         hdr.version_minor = PCAP_VERSION_MINOR;
 385
 386         hdr.thiszone = thiszone;
 387         hdr.snaplen = snaplen;
 388         hdr.sigfigs = 0;
 389         hdr.linktype = linktype;
 390
 391         if (fwrite((char *)&hdr, sizeof(hdr), 1, fp) != 1)
 392                 return (-1);
 393
 394         return (0);
 395 }
 396
 397 static void
 398 swap_hdr(struct pcap_file_header *hp)
 399 {
 400         hp->version_major = SWAPSHORT(hp->version_major);
 401         hp->version_minor = SWAPSHORT(hp->version_minor);
 402         hp->thiszone = SWAPLONG(hp->thiszone);
 403         hp->sigfigs = SWAPLONG(hp->sigfigs);
 404         hp->snaplen = SWAPLONG(hp->snaplen);
 405         hp->linktype = SWAPLONG(hp->linktype);
 406 }
 407
 408 pcap_t *
 409 pcap_open_offline(const char *fname, char *errbuf)
 410 {
 411         register pcap_t *p;
 412         register FILE *fp;
 413         struct pcap_file_header hdr;
 414         bpf_u_int32 magic;
 415         int linklen;
 416
 417         p = (pcap_t *)malloc(sizeof(*p));
 418         if (p == NULL) {
 419                 strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
 420                 return (NULL);
 421         }
 422
 423         memset((char *)p, 0, sizeof(*p));
 424         /*
 425          * Set this field so we don't close stdin in pcap_close!
 426          */
 427 #ifndef WIN32
 428         p->fd = -1;
 429 #else
 430         p->adapter = NULL;
 431 #endif
 432
 433         if (fname[0] == '-' && fname[1] == '\0')
 434                 fp = stdin;
 435         else {
 436 #ifndef WIN32
 437                 fp = fopen(fname, "r");
 438 #else
 439                 fp = fopen(fname, "rb");
 440 #endif
 441                 if (fp == NULL) {
 442                         snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname,
 443                             pcap_strerror(errno));
 444                         goto bad;
 445                 }
 446         }
 447         if (fread((char *)&hdr, sizeof(hdr), 1, fp) != 1) {
 448                 snprintf(errbuf, PCAP_ERRBUF_SIZE, "fread: %s",
 449                     pcap_strerror(errno));
 450                 goto bad;
 451         }
 452         magic = hdr.magic;
 453         if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
 454                 magic = SWAPLONG(magic);
 455                 if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
 456                         snprintf(errbuf, PCAP_ERRBUF_SIZE,
 457                             "bad dump file format");
 458                         goto bad;
 459                 }
 460                 p->sf.swapped = 1;
 461                 swap_hdr(&hdr);
 462         }
 463         if (magic == PATCHED_TCPDUMP_MAGIC) {
 464                 /*
 465                  * XXX - the patch that's in some versions of libpcap
 466                  * changes the packet header but not the magic number;
 467                  * we'd have to use some hacks^H^H^H^H^Hheuristics to
 468                  * detect that.
 469                  */
 470                 p->sf.hdrsize = sizeof(struct pcap_sf_patched_pkthdr);
 471         } else
 472                 p->sf.hdrsize = sizeof(struct pcap_sf_pkthdr);
 473         if (hdr.version_major < PCAP_VERSION_MAJOR) {
 474                 snprintf(errbuf, PCAP_ERRBUF_SIZE, "archaic file format");
 475                 goto bad;
 476         }
 477         p->tzoff = hdr.thiszone;
 478         p->snapshot = hdr.snaplen;
 479         p->linktype = linktype_to_dlt(hdr.linktype);
 480         p->sf.rfile = fp;
 481 #ifndef WIN32
 482         p->bufsize = hdr.snaplen;
 483 #else
 484         /* Allocate the space for pcap_pkthdr as well. It will be used by pcap_read_ex */
 485         p->bufsize = hdr.snaplen+sizeof(struct pcap_pkthdr);
 486 #endif
 487
 488         /* Align link header as required for proper data alignment */
 489         /* XXX should handle all types */
 490         switch (p->linktype) {
 491
 492         case DLT_EN10MB:
 493                 linklen = 14;
 494                 break;
 495
 496         case DLT_FDDI:
 497                 linklen = 13 + 8;       /* fddi_header + llc */
 498                 break;
 499
 500         case DLT_NULL:
 501         default:
 502                 linklen = 0;
 503                 break;
 504         }
 505
 506         if (p->bufsize < 0)
 507                 p->bufsize = BPF_MAXBUFSIZE;
 508         p->sf.base = (u_char *)malloc(p->bufsize + BPF_ALIGNMENT);
 509         if (p->sf.base == NULL) {
 510                 strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
 511                 goto bad;
 512         }
 513         p->buffer = p->sf.base + BPF_ALIGNMENT - (linklen % BPF_ALIGNMENT);
 514         p->sf.version_major = hdr.version_major;
 515         p->sf.version_minor = hdr.version_minor;
 516 #ifdef PCAP_FDDIPAD
 517         /* XXX padding only needed for kernel fcode */
 518         pcap_fddipad = 0;
 519 #endif
 520
 521         return (p);
 522  bad:
 523         if(fp)
 524                 fclose(fp);
 525         free(p);
 526         return (NULL);
 527 }
 528
 529 /*
 530  * Read sf_readfile and return the next packet.  Return the header in hdr
 531  * and the contents in buf.  Return 0 on success, SFERR_EOF if there were
 532  * no more packets, and SFERR_TRUNC if a partial packet was encountered.
 533  */
 534 static int
 535 sf_next_packet(pcap_t *p, struct pcap_pkthdr *hdr, u_char *buf, int buflen)
 536 {
 537         struct pcap_sf_patched_pkthdr sf_hdr;
 538         FILE *fp = p->sf.rfile;
 539
 540         /*
 541          * Read the packet header; the structure we use as a buffer
 542          * is the longer structure for files generated by the patched
 543          * libpcap, but if the file has the magic number for an
 544          * unpatched libpcap we only read as many bytes as the regular
 545          * header has.
 546          */
 547         if (fread(&sf_hdr, p->sf.hdrsize, 1, fp) != 1) {
 548                 /* probably an EOF, though could be a truncated packet */
 549                 return (1);
 550         }
 551
 552         if (p->sf.swapped) {
 553                 /* these were written in opposite byte order */
 554                 hdr->caplen = SWAPLONG(sf_hdr.caplen);
 555                 hdr->len = SWAPLONG(sf_hdr.len);
 556                 hdr->ts.tv_sec = SWAPLONG(sf_hdr.ts.tv_sec);
 557                 hdr->ts.tv_usec = SWAPLONG(sf_hdr.ts.tv_usec);
 558         } else {
 559                 hdr->caplen = sf_hdr.caplen;
 560                 hdr->len = sf_hdr.len;
 561                 hdr->ts.tv_sec = sf_hdr.ts.tv_sec;
 562                 hdr->ts.tv_usec = sf_hdr.ts.tv_usec;
 563         }
 564         /*
 565          * We interchanged the caplen and len fields at version 2.3,
 566          * in order to match the bpf header layout.  But unfortunately
 567          * some files were written with version 2.3 in their headers
 568          * but without the interchanged fields.
 569          */
 570         if (p->sf.version_minor < 3 ||
 571             (p->sf.version_minor == 3 && hdr->caplen > hdr->len)) {
 572                 int t = hdr->caplen;
 573                 hdr->caplen = hdr->len;
 574                 hdr->len = t;
 575         }
 576
 577         if (hdr->caplen > buflen) {
 578                 /*
 579                  * This can happen due to Solaris 2.3 systems tripping
 580                  * over the BUFMOD problem and not setting the snapshot
 581                  * correctly in the savefile header.  If the caplen isn't
 582                  * grossly wrong, try to salvage.
 583                  */
 584                 static u_char *tp = NULL;
 585                 static int tsize = 0;
 586
 587                 if (hdr->caplen > 65535) {
 588                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 589                             "bogus savefile header");
 590                         return (-1);
 591                 }
 592
 593                 if (tsize < hdr->caplen) {
 594                         tsize = ((hdr->caplen + 1023) / 1024) * 1024;
 595                         if (tp != NULL)
 596                                 free((u_char *)tp);
 597                         tp = (u_char *)malloc(tsize);
 598                         if (tp == NULL) {
 599                                 tsize = 0;
 600                                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 601                                     "BUFMOD hack malloc");
 602                                 return (-1);
 603                         }
 604                 }
 605                 if (fread((char *)tp, hdr->caplen, 1, fp) != 1) {
 606                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 607                             "truncated dump file");
 608                         return (-1);
 609                 }
 610                 /*
 611                  * We can only keep up to buflen bytes.  Since caplen > buflen
 612                  * is exactly how we got here, we know we can only keep the
 613                  * first buflen bytes and must drop the remainder.  Adjust
 614                  * caplen accordingly, so we don't get confused later as
 615                  * to how many bytes we have to play with.
 616                  */
 617                 hdr->caplen = buflen;
 618                 memcpy((char *)buf, (char *)tp, buflen);
 619
 620         } else {
 621                 /* read the packet itself */
 622
 623                 if (fread((char *)buf, hdr->caplen, 1, fp) != 1) {
 624                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 625                             "truncated dump file");
 626                         return (-1);
 627                 }
 628         }
 629         return (0);
 630 }
 631
 632 /*
 633  * Print out packets stored in the file initialized by sf_read_init().
 634  * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
 635  */
 636 int
 637 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 638 {
 639         struct bpf_insn *fcode = p->fcode.bf_insns;
 640         int status = 0;
 641         int n = 0;
 642
 643         while (status == 0) {
 644                 struct pcap_pkthdr h;
 645
 646                 status = sf_next_packet(p, &h, p->buffer, p->bufsize);
 647                 if (status) {
 648                         if (status == 1)
 649                                 return (0);
 650                         return (status);
 651                 }
 652
 653                 if (fcode == NULL ||
 654                     bpf_filter(fcode, p->buffer, h.len, h.caplen)) {
 655                         (*callback)(user, &h, p->buffer);
 656                         if (++n >= cnt && cnt > 0)
 657                                 break;
 658                 }
 659         }
 660         /*XXX this breaks semantics tcpslice expects */
 661         return (n);
 662 }
 663
 664 /*
 665  * Output a packet to the initialized dump file.
 666  */
 667 void
 668 pcap_dump(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 669 {
 670         register FILE *f;
 671         struct pcap_sf_pkthdr sf_hdr;
 672
 673         f = (FILE *)user;
 674         sf_hdr.ts.tv_sec  = h->ts.tv_sec;
 675         sf_hdr.ts.tv_usec = h->ts.tv_usec;
 676         sf_hdr.caplen     = h->caplen;
 677         sf_hdr.len        = h->len;
 678         /* XXX we should check the return status */
 679         (void)fwrite(&sf_hdr, sizeof(sf_hdr), 1, f);
 680         (void)fwrite((char *)sp, h->caplen, 1, f);
 681 }
 682
 683 /*
 684  * Initialize so that sf_write() will output to the file named 'fname'.
 685  */
 686 pcap_dumper_t *
 687 pcap_dump_open(pcap_t *p, const char *fname)
 688 {
 689         FILE *f;
 690         int linktype;
 691
 692         linktype = dlt_to_linktype(p->linktype);
 693         if (linktype == -1) {
 694                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 695                     "%s: link-layer type %d isn't supported in savefiles",
 696                     fname, linktype);
 697                 return (NULL);
 698         }
 699
 700         if (fname[0] == '-' && fname[1] == '\0') {
 701                 f = stdout;
 702 #ifdef WIN32
 703                 _setmode(_fileno(f), _O_BINARY);
 704 #endif
 705         } else {
 706 #ifndef WIN32
 707                 f = fopen(fname, "w");
 708 #else
 709                 f = fopen(fname, "wb");
 710                 setbuf(f, NULL);        /* XXX - why? */
 711 #endif
 712                 if (f == NULL) {
 713                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
 714                             fname, pcap_strerror(errno));
 715                         return (NULL);
 716                 }
 717         }
 718         (void)sf_write_header(f, linktype, p->tzoff, p->snapshot);
 719         return ((pcap_dumper_t *)f);
 720 }
 721
 722 int
 723 pcap_dump_flush(pcap_dumper_t *p)
 724 {
 725
 726         if (fflush((FILE *)p) == EOF)
 727                 return (-1);
 728         else
 729                 return (0);
 730 }
 731
 732 void
 733 pcap_dump_close(pcap_dumper_t *p)
 734 {
 735
 736 #ifdef notyet
 737         if (ferror((FILE *)p))
 738                 return-an-error;
 739         /* XXX should check return from fclose() too */
 740 #endif
 741         (void)fclose((FILE *)p);
 742 }