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# savefile.c

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    00001 /*
    00002  * Copyright (c) 1993, 1994, 1995, 1996, 1997
    00003  *  The Regents of the University of California.  All rights reserved.
    00004  *
    00005  * Redistribution and use in source and binary forms, with or without
    00006  * modification, are permitted provided that: (1) source code distributions
    00007  * retain the above copyright notice and this paragraph in its entirety, (2)
    00008  * distributions including binary code include the above copyright notice and
    00009  * this paragraph in its entirety in the documentation or other materials
    00010  * provided with the distribution, and (3) all advertising materials mentioning
    00011  * features or use of this software display the following acknowledgement:
    00012  * ``This product includes software developed by the University of California,
    00013  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
    00014  * the University nor the names of its contributors may be used to endorse
    00015  * or promote products derived from this software without specific prior
    00016  * written permission.
    00017  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
    00018  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
    00019  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
    00020  *
    00021  * savefile.c - supports offline use of tcpdump
    00022  *  Extraction/creation by Jeffrey Mogul, DECWRL
    00023  *  Modified by Steve McCanne, LBL.
    00024  *
    00025  * Used to save the received packet headers, after filtering, to
    00026  * a file, and then read them later.
    00027  * The first record in the file contains saved values for the machine
    00028  * dependent values so we can print the dump file on any architecture.
    00029  */
    00030
    00031 #ifndef lint
    00032 static const char rcsid[] _U_ =
    00033     "@(#) $Header: /tcpdump/master/libpcap/savefile.c,v 1.100 2003/12/21 21:58:50 guy Exp $ (LBL)";
    00034 #endif
    00035
    00036 #ifdef HAVE_CONFIG_H
    00037 #include "config.h"
    00038 #endif
    00039
    00040 #include <errno.h>
    00041 #include <memory.h>
    00042 #include <stdio.h>
    00043 #include <stdlib.h>
    00044 #include <string.h>
    00045
    00046 #include "pcap-int.h"
    00047
    00048 #ifdef HAVE_OS_PROTO_H
    00049 #include "os-proto.h"
    00050 #endif
    00051
    00052 #define TCPDUMP_MAGIC 0xa1b2c3d4
    00053 #define PATCHED_TCPDUMP_MAGIC 0xa1b2cd34
    00054
    00055 /*
    00056  * We use the "receiver-makes-right" approach to byte order,
    00057  * because time is at a premium when we are writing the file.
    00058  * In other words, the pcap_file_header and pcap_pkthdr,
    00059  * records are written in host byte order.
    00060  * Note that the bytes of packet data are written out in the order in
    00061  * which they were received, so multi-byte fields in packets are not
    00062  * written in host byte order, they're written in whatever order the
    00063  * sending machine put them in.
    00064  *
    00065  * ntoh[ls] aren't sufficient because we might need to swap on a big-endian
    00066  * machine (if the file was written in little-end order).
    00067  */
    00068 #define SWAPLONG(y) \
    00069 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
    00070 #define SWAPSHORT(y) \
    00071     ( (((y)&0xff)<<8) | ((u_short)((y)&0xff00)>>8) )
    00072
    00073 #define SFERR_TRUNC     1
    00074 #define SFERR_BADVERSION    2
    00075 #define SFERR_BADF      3
    00076 #define SFERR_EOF       4 /* not really an error, just a status */
    00077
    00078 /*
    00079  * We don't write DLT_* values to the capture file header, because
    00080  * they're not the same on all platforms.
    00081  *
    00082  * Unfortunately, the various flavors of BSD have not always used the same
    00083  * numerical values for the same data types, and various patches to
    00084  * libpcap for non-BSD OSes have added their own DLT_* codes for link
    00085  * layer encapsulation types seen on those OSes, and those codes have had,
    00086  * in some cases, values that were also used, on other platforms, for other
    00087  * link layer encapsulation types.
    00088  *
    00089  * This means that capture files of a type whose numerical DLT_* code
    00090  * means different things on different BSDs, or with different versions
    00091  * of libpcap, can't always be read on systems other than those like
    00092  * the one running on the machine on which the capture was made.
    00093  *
    00094  * Instead, we define here a set of LINKTYPE_* codes, and map DLT_* codes
    00095  * to LINKTYPE_* codes when writing a savefile header, and map LINKTYPE_*
    00096  * codes to DLT_* codes when reading a savefile header.
    00097  *
    00098  * For those DLT_* codes that have, as far as we know, the same values on
    00099  * all platforms (DLT_NULL through DLT_FDDI), we define LINKTYPE_xxx as
    00100  * DLT_xxx; that way, captures of those types can still be read by
    00101  * versions of libpcap that map LINKTYPE_* values to DLT_* values, and
    00102  * captures of those types written by versions of libpcap that map DLT_
    00103  * values to LINKTYPE_ values can still be read by older versions
    00104  * of libpcap.
    00105  *
    00106  * The other LINKTYPE_* codes are given values starting at 100, in the
    00107  * hopes that no DLT_* code will be given one of those values.
    00108  *
    00109  * In order to ensure that a given LINKTYPE_* code's value will refer to
    00110  * the same encapsulation type on all platforms, you should not allocate
    00111  * a new LINKTYPE_* value without consulting "tcpdump-workers@tcpdump.org".
    00112  * The tcpdump developers will allocate a value for you, and will not
    00113  * subsequently allocate it to anybody else; that value will be added to
    00114  * the "pcap.h" in the tcpdump.org CVS repository, so that a future
    00115  * libpcap release will include it.
    00116  *
    00117  * You should, if possible, also contribute patches to libpcap and tcpdump
    00118  * to handle the new encapsulation type, so that they can also be checked
    00119  * into the tcpdump.org CVS repository and so that they will appear in
    00120  * future libpcap and tcpdump releases.
    00121  */
    00122 #define LINKTYPE_NULL       DLT_NULL
    00123 #define LINKTYPE_ETHERNET   DLT_EN10MB  /* also for 100Mb and up */
    00124 #define LINKTYPE_EXP_ETHERNET   DLT_EN3MB   /* 3Mb experimental Ethernet */
    00125 #define LINKTYPE_AX25       DLT_AX25
    00126 #define LINKTYPE_PRONET     DLT_PRONET
    00127 #define LINKTYPE_CHAOS      DLT_CHAOS
    00128 #define LINKTYPE_TOKEN_RING DLT_IEEE802 /* DLT_IEEE802 is used for Token Ring */
    00129 #define LINKTYPE_ARCNET     DLT_ARCNET  /* BSD-style headers */
    00130 #define LINKTYPE_SLIP       DLT_SLIP
    00131 #define LINKTYPE_PPP        DLT_PPP
    00132 #define LINKTYPE_FDDI       DLT_FDDI
    00133
    00134 /*
    00135  * LINKTYPE_PPP is for use when there might, or might not, be an RFC 1662
    00136  * PPP in HDLC-like framing header (with 0xff 0x03 before the PPP protocol
    00137  * field) at the beginning of the packet.
    00138  *
    00139  * This is for use when there is always such a header; the address field
    00140  * might be 0xff, for regular PPP, or it might be an address field for Cisco
    00141  * point-to-point with HDLC framing as per section 4.3.1 of RFC 1547 ("Cisco
    00142  * HDLC").  This is, for example, what you get with NetBSD's DLT_PPP_SERIAL.
    00143  *
    00144  * We give it the same value as NetBSD's DLT_PPP_SERIAL, in the hopes that
    00145  * nobody else will choose a DLT_ value of 50, and so that DLT_PPP_SERIAL
    00146  * captures will be written out with a link type that NetBSD's tcpdump
    00147  * can read.
    00148  */
    00149 #define LINKTYPE_PPP_HDLC   50      /* PPP in HDLC-like framing */
    00150
    00151 #define LINKTYPE_PPP_ETHER  51      /* NetBSD PPP-over-Ethernet */
    00152
    00153 #define LINKTYPE_ATM_RFC1483    100     /* LLC/SNAP-encapsulated ATM */
    00154 #define LINKTYPE_RAW        101     /* raw IP */
    00155 #define LINKTYPE_SLIP_BSDOS 102     /* BSD/OS SLIP BPF header */
    00156 #define LINKTYPE_PPP_BSDOS  103     /* BSD/OS PPP BPF header */
    00157 #define LINKTYPE_C_HDLC     104     /* Cisco HDLC */
    00158 #define LINKTYPE_IEEE802_11 105     /* IEEE 802.11 (wireless) */
    00159 #define LINKTYPE_ATM_CLIP   106     /* Linux Classical IP over ATM */
    00160 #define LINKTYPE_FRELAY     107     /* Frame Relay */
    00161 #define LINKTYPE_LOOP       108     /* OpenBSD loopback */
    00162 #define LINKTYPE_ENC        109     /* OpenBSD IPSEC enc */
    00163
    00164 #define LINKTYPE_LINUX_SLL  113     /* Linux cooked socket capture */
    00165 #define LINKTYPE_LTALK      114     /* Apple LocalTalk hardware */
    00166 #define LINKTYPE_ECONET     115     /* Acorn Econet */
    00167
    00168 #define LINKTYPE_PFLOG      117     /* OpenBSD DLT_PFLOG */
    00169 #define LINKTYPE_CISCO_IOS  118     /* For Cisco-internal use */
    00170 #define LINKTYPE_PRISM_HEADER   119     /* 802.11+Prism II monitor mode */
    00171 #define LINKTYPE_AIRONET_HEADER 120     /* FreeBSD Aironet driver stuff */
    00172 #define LINKTYPE_IP_OVER_FC 122     /* RFC 2625 IP-over-Fibre Channel */
    00173 #define LINKTYPE_SUNATM     123     /* Solaris+SunATM */
    00174
    00175 #define LINKTYPE_IEEE802_11_RADIO 127       /* 802.11 plus WLAN header */
    00176
    00177 #define LINKTYPE_TZSP       128     /* Tazmen Sniffer Protocol */
    00178
    00179 #define LINKTYPE_ARCNET_LINUX   129     /* Linux-style headers */
    00180
    00181 #define LINKTYPE_JUNIPER_MLPPP  130     /* Juniper-internal chassis encapsulation */
    00182 #define LINKTYPE_JUNIPER_MLFR   131
    00183 #define LINKTYPE_JUNIPER_ES     132
    00184 #define LINKTYPE_JUNIPER_GGSN   133
    00185 #define LINKTYPE_JUNIPER_MFR    134
    00186 #define LINKTYPE_JUNIPER_ATM2   135
    00187 #define LINKTYPE_JUNIPER_SERVICES 136
    00188 #define LINKTYPE_JUNIPER_ATM1   137
    00189
    00190 #define LINKTYPE_APPLE_IP_OVER_IEEE1394 138 /* Apple IP-over-IEEE 1394 cooked header */
    00191
    00192 #define LINKTYPE_RAWSS7         139             /* see rawss7.h for */
    00193 #define LINKTYPE_RAWSS7_MTP2    140         /* information  on these */
    00194 #define LINKTYPE_RAWSS7_MTP3    141             /* definitions */
    00195 #define LINKTYPE_RAWSS7_SCCP    142
    00196
    00197 #define LINKTYPE_DOCSIS     143     /* DOCSIS MAC frames */
    00198
    00199 #define LINKTYPE_LINUX_IRDA 144     /* Linux-IrDA */
    00200
    00201 /*
    00202  * These types are reserved for future use.
    00203  */
    00204 #define LINKTYPE_LANE8023   110     /* ATM LANE + 802.3 */
    00205 #define LINKTYPE_HIPPI      111     /* NetBSD HIPPI */
    00206 #define LINKTYPE_HDLC       112     /* NetBSD HDLC framing */
    00207 #define LINKTYPE_IPFILTER   116     /* IP Filter capture files */
    00208 #define LINKTYPE_HHDLC      121     /* Siemens HiPath HDLC */
    00209 #define LINKTYPE_RIO        124     /* RapidIO */
    00210 #define LINKTYPE_PCI_EXP    125     /* PCI Express */
    00211 #define LINKTYPE_AURORA     126     /* Xilinx Aurora link layer */
    00212 #define LINKTYPE_IBM_SP     145     /* IBM SP switch */
    00213 #define LINKTYPE_IBM_SN     146     /* IBM Next Federation switch */
    00214
    00215 static struct linktype_map {
    00216     int dlt;
    00217     int linktype;
    00218 } map[] = {
    00219     /*
    00220      * These DLT_* codes have LINKTYPE_* codes with values identical
    00221      * to the values of the corresponding DLT_* code.
    00222      */
    00223     { DLT_NULL,     LINKTYPE_NULL },
    00224     { DLT_EN10MB,       LINKTYPE_ETHERNET },
    00225     { DLT_EN3MB,        LINKTYPE_EXP_ETHERNET },
    00226     { DLT_AX25,     LINKTYPE_AX25 },
    00227     { DLT_PRONET,       LINKTYPE_PRONET },
    00228     { DLT_CHAOS,        LINKTYPE_CHAOS },
    00229     { DLT_IEEE802,      LINKTYPE_TOKEN_RING },
    00230     { DLT_ARCNET,       LINKTYPE_ARCNET },
    00231     { DLT_SLIP,     LINKTYPE_SLIP },
    00232     { DLT_PPP,      LINKTYPE_PPP },
    00233     { DLT_FDDI,     LINKTYPE_FDDI },
    00234
    00235     /*
    00236      * These DLT_* codes have different values on different
    00237      * platforms; we map them to LINKTYPE_* codes that
    00238      * have values that should never be equal to any DLT_*
    00239      * code.
    00240      */
    00241 #ifdef DLT_FR
    00242     /* BSD/OS Frame Relay */
    00243     { DLT_FR,       LINKTYPE_FRELAY },
    00244 #endif
    00245     { DLT_ATM_RFC1483,  LINKTYPE_ATM_RFC1483 },
    00246     { DLT_RAW,      LINKTYPE_RAW },
    00247     { DLT_SLIP_BSDOS,   LINKTYPE_SLIP_BSDOS },
    00248     { DLT_PPP_BSDOS,    LINKTYPE_PPP_BSDOS },
    00249
    00250     /* BSD/OS Cisco HDLC */
    00251     { DLT_C_HDLC,       LINKTYPE_C_HDLC },
    00252
    00253     /*
    00254      * These DLT_* codes are not on all platforms, but, so far,
    00255      * there don't appear to be any platforms that define
    00256      * other codes with those values; we map them to
    00257      * different LINKTYPE_* values anyway, just in case.
    00258      */
    00259
    00260     /* Linux ATM Classical IP */
    00261     { DLT_ATM_CLIP,     LINKTYPE_ATM_CLIP },
    00262
    00263     /* NetBSD sync/async serial PPP (or Cisco HDLC) */
    00264     { DLT_PPP_SERIAL,   LINKTYPE_PPP_HDLC },
    00265
    00266     /* NetBSD PPP over Ethernet */
    00267     { DLT_PPP_ETHER,    LINKTYPE_PPP_ETHER },
    00268
    00269     /* IEEE 802.11 wireless */
    00270     { DLT_IEEE802_11,   LINKTYPE_IEEE802_11 },
    00271
    00272     /* Frame Relay */
    00273     { DLT_FRELAY,       LINKTYPE_FRELAY },
    00274
    00275     /* OpenBSD loopback */
    00276     { DLT_LOOP,     LINKTYPE_LOOP },
    00277
    00278     /* Linux cooked socket capture */
    00279     { DLT_LINUX_SLL,    LINKTYPE_LINUX_SLL },
    00280
    00281     /* Apple LocalTalk hardware */
    00282     { DLT_LTALK,        LINKTYPE_LTALK },
    00283
    00284     /* Acorn Econet */
    00285     { DLT_ECONET,       LINKTYPE_ECONET },
    00286
    00287     /* OpenBSD DLT_PFLOG */
    00288     { DLT_PFLOG,        LINKTYPE_PFLOG },
    00289
    00290     /* For Cisco-internal use */
    00291     { DLT_CISCO_IOS,    LINKTYPE_CISCO_IOS },
    00292
    00293     /* Prism II monitor-mode header plus 802.11 header */
    00294     { DLT_PRISM_HEADER, LINKTYPE_PRISM_HEADER },
    00295
    00296     /* FreeBSD Aironet driver stuff */
    00297     { DLT_AIRONET_HEADER,   LINKTYPE_AIRONET_HEADER },
    00298
    00299     /* Siemens HiPath HDLC */
    00300     { DLT_HHDLC,        LINKTYPE_HHDLC },
    00301
    00302     /* RFC 2625 IP-over-Fibre Channel */
    00303     { DLT_IP_OVER_FC,   LINKTYPE_IP_OVER_FC },
    00304
    00305     /* Solaris+SunATM */
    00306     { DLT_SUNATM,       LINKTYPE_SUNATM },
    00307
    00308     /* RapidIO */
    00309     { DLT_RIO,      LINKTYPE_RIO },
    00310
    00311     /* PCI Express */
    00312     { DLT_PCI_EXP,      LINKTYPE_PCI_EXP },
    00313
    00314     /* Xilinx Aurora link layer */
    00315     { DLT_AURORA,       LINKTYPE_AURORA },
    00316
    00317     /* 802.11 plus WLAN header */
    00318     { DLT_IEEE802_11_RADIO, LINKTYPE_IEEE802_11_RADIO },
    00319
    00320     /* Tazmen Sniffer Protocol */
    00321     { DLT_TZSP,     LINKTYPE_TZSP },
    00322
    00323     /* Arcnet with Linux-style link-layer headers */
    00324     { DLT_ARCNET_LINUX, LINKTYPE_ARCNET_LINUX },
    00325
    00326         /* Juniper-internal chassis encapsulation */
    00327         { DLT_JUNIPER_MLPPP,    LINKTYPE_JUNIPER_MLPPP },
    00328         { DLT_JUNIPER_MLFR,     LINKTYPE_JUNIPER_MLFR },
    00329         { DLT_JUNIPER_ES,       LINKTYPE_JUNIPER_ES },
    00330         { DLT_JUNIPER_GGSN,     LINKTYPE_JUNIPER_GGSN },
    00331         { DLT_JUNIPER_MFR,      LINKTYPE_JUNIPER_MFR },
    00332         { DLT_JUNIPER_ATM2,     LINKTYPE_JUNIPER_ATM2 },
    00333         { DLT_JUNIPER_SERVICES, LINKTYPE_JUNIPER_SERVICES },
    00334         { DLT_JUNIPER_ATM1,     LINKTYPE_JUNIPER_ATM1 },
    00335
    00336     /* Apple IP-over-IEEE 1394 cooked header */
    00337     { DLT_APPLE_IP_OVER_IEEE1394, LINKTYPE_APPLE_IP_OVER_IEEE1394 },
    00338
    00339     /* DOCSIS MAC frames */
    00340     { DLT_DOCSIS,       LINKTYPE_DOCSIS },
    00341
    00342     /* IrDA IrLAP packets + Linux-cooked header */
    00343     { DLT_LINUX_IRDA,   LINKTYPE_LINUX_IRDA },
    00344
    00345     /* IBM SP and Next Federation switches */
    00346     { DLT_IBM_SP,       LINKTYPE_IBM_SP },
    00347     { DLT_IBM_SN,       LINKTYPE_IBM_SN },
    00348
    00349     /*
    00350      * Any platform that defines additional DLT_* codes should:
    00351      *
    00352      *  request a LINKTYPE_* code and value from tcpdump.org,
    00353      *  as per the above;
    00354      *
    00355      *  add, in their version of libpcap, an entry to map
    00356      *  those DLT_* codes to the corresponding LINKTYPE_*
    00357      *  code;
    00358      *
    00359      *  redefine, in their "net/bpf.h", any DLT_* values
    00360      *  that collide with the values used by their additional
    00361      *  DLT_* codes, to remove those collisions (but without
    00362      *  making them collide with any of the LINKTYPE_*
    00363      *  values equal to 50 or above; they should also avoid
    00364      *  defining DLT_* values that collide with those
    00365      *  LINKTYPE_* values, either).
    00366      */
    00367     { -1,           -1 }
    00368 };
    00369
    00370 static int
    00371 dlt_to_linktype(int dlt)
    00372 {
    00373     int i;
    00374
    00375     for (i = 0; map[i].dlt != -1; i++) {
    00376         if (map[i].dlt == dlt)
    00377             return (map[i].linktype);
    00378     }
    00379
    00380     /*
    00381      * If we don't have a mapping for this DLT_ code, return an
    00382      * error; that means that the table above needs to have an
    00383      * entry added.
    00384      */
    00385     return (-1);
    00386 }
    00387
    00388 static int
    00389 linktype_to_dlt(int linktype)
    00390 {
    00391     int i;
    00392
    00393     for (i = 0; map[i].linktype != -1; i++) {
    00394         if (map[i].linktype == linktype)
    00395             return (map[i].dlt);
    00396     }
    00397
    00398     /*
    00399      * If we don't have an entry for this link type, return
    00400      * the link type value; it may be a DLT_ value from an
    00401      * older version of libpcap.
    00402      */
    00403     return linktype;
    00404 }
    00405
    00406 static int
    00407 sf_write_header(FILE *fp, int linktype, int thiszone, int snaplen)
    00408 {
    00409     struct pcap_file_header hdr;
    00410
    00411     hdr.magic = TCPDUMP_MAGIC;
    00412     hdr.version_major = PCAP_VERSION_MAJOR;
    00413     hdr.version_minor = PCAP_VERSION_MINOR;
    00414
    00415     hdr.thiszone = thiszone;
    00416     hdr.snaplen = snaplen;
    00417     hdr.sigfigs = 0;
    00418     hdr.linktype = linktype;
    00419
    00420     if (fwrite((char *)&hdr, sizeof(hdr), 1, fp) != 1)
    00421         return (-1);
    00422
    00423     return (0);
    00424 }
    00425
    00426 static void
    00427 swap_hdr(struct pcap_file_header *hp)
    00428 {
    00429     hp->version_major = SWAPSHORT(hp->version_major);
    00430     hp->version_minor = SWAPSHORT(hp->version_minor);
    00431     hp->thiszone = SWAPLONG(hp->thiszone);
    00432     hp->sigfigs = SWAPLONG(hp->sigfigs);
    00433     hp->snaplen = SWAPLONG(hp->snaplen);
    00434     hp->linktype = SWAPLONG(hp->linktype);
    00435 }
    00436
    00437 static int
    00438 sf_getnonblock(pcap_t *p, char *errbuf)
    00439 {
    00440     /*
    00441      * This is a savefile, not a live capture file, so never say
    00442      * it's in non-blocking mode.
    00443      */
    00444     return (0);
    00445 }
    00446
    00447 static int
    00448 sf_setnonblock(pcap_t *p, int nonblock, char *errbuf)
    00449 {
    00450     /*
    00451      * This is a savefile, not a live capture file, so ignore
    00452      * requests to put it in non-blocking mode.
    00453      */
    00454     return (0);
    00455 }
    00456
    00457 static int
    00458 sf_stats(pcap_t *p, struct pcap_stat *ps)
    00459 {
    00460     snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
    00461         "Statistics aren't available from savefiles");
    00462     return (-1);
    00463 }
    00464
    00465 static void
    00466 sf_close(pcap_t *p)
    00467 {
    00468     if (p->sf.rfile != stdin)
    00469         (void)fclose(p->sf.rfile);
    00470     if (p->sf.base != NULL)
    00471         free(p->sf.base);
    00472 }
    00473
    00474 pcap_t *
    00475 pcap_open_offline(const char *fname, char *errbuf)
    00476 {
    00477     register pcap_t *p;
    00478     register FILE *fp;
    00479     struct pcap_file_header hdr;
    00480     bpf_u_int32 magic;
    00481     int linklen;
    00482
    00483     p = (pcap_t *)malloc(sizeof(*p));
    00484     if (p == NULL) {
    00485         strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
    00486         return (NULL);
    00487     }
    00488
    00489     memset((char *)p, 0, sizeof(*p));
    00490
    00491     if (fname[0] == '-' && fname[1] == '\0')
    00492         fp = stdin;
    00493     else {
    00494 #ifndef WIN32
    00495         fp = fopen(fname, "r");
    00496 #else
    00497         fp = fopen(fname, "rb");
    00498 #endif
    00499         if (fp == NULL) {
    00500             snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: %s", fname,
    00501                 pcap_strerror(errno));
    00502             goto bad;
    00503         }
    00504     }
    00505     if (fread((char *)&hdr, sizeof(hdr), 1, fp) != 1) {
    00506         snprintf(errbuf, PCAP_ERRBUF_SIZE, "fread: %s",
    00507             pcap_strerror(errno));
    00508         goto bad;
    00509     }
    00510     magic = hdr.magic;
    00511     if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
    00512         magic = SWAPLONG(magic);
    00513         if (magic != TCPDUMP_MAGIC && magic != PATCHED_TCPDUMP_MAGIC) {
    00514             snprintf(errbuf, PCAP_ERRBUF_SIZE,
    00515                 "bad dump file format");
    00516             goto bad;
    00517         }
    00518         p->sf.swapped = 1;
    00519         swap_hdr(&hdr);
    00520     }
    00521     if (magic == PATCHED_TCPDUMP_MAGIC) {
    00522         /*
    00523          * XXX - the patch that's in some versions of libpcap
    00524          * changes the packet header but not the magic number;
    00525          * we'd have to use some hacks^H^H^H^H^Hheuristics to
    00526          * detect that.
    00527          */
    00528         p->sf.hdrsize = sizeof(struct pcap_sf_patched_pkthdr);
    00529     } else
    00530         p->sf.hdrsize = sizeof(struct pcap_sf_pkthdr);
    00531     if (hdr.version_major < PCAP_VERSION_MAJOR) {
    00532         snprintf(errbuf, PCAP_ERRBUF_SIZE, "archaic file format");
    00533         goto bad;
    00534     }
    00535     p->tzoff = hdr.thiszone;
    00536     p->snapshot = hdr.snaplen;
    00537     p->linktype = linktype_to_dlt(hdr.linktype);
    00538     p->sf.rfile = fp;
    00539 #ifndef WIN32
    00540     p->bufsize = hdr.snaplen;
    00541 #else
    00542     /* Allocate the space for pcap_pkthdr as well. It will be used by pcap_read_ex */
    00543     p->bufsize = hdr.snaplen+sizeof(struct pcap_pkthdr);
    00544 #endif
    00545
    00546     /* Align link header as required for proper data alignment */
    00547     /* XXX should handle all types */
    00548     switch (p->linktype) {
    00549
    00550     case DLT_EN10MB:
    00551         linklen = 14;
    00552         break;
    00553
    00554     case DLT_FDDI:
    00555         linklen = 13 + 8;   /* fddi_header + llc */
    00556         break;
    00557
    00558     case DLT_NULL:
    00559     default:
    00560         linklen = 0;
    00561         break;
    00562     }
    00563
    00564     if (p->bufsize < 0)
    00565         p->bufsize = BPF_MAXBUFSIZE;
    00566     p->sf.base = (u_char *)malloc(p->bufsize + BPF_ALIGNMENT);
    00567     if (p->sf.base == NULL) {
    00568         strlcpy(errbuf, "out of swap", PCAP_ERRBUF_SIZE);
    00569         goto bad;
    00570     }
    00571     p->buffer = p->sf.base + BPF_ALIGNMENT - (linklen % BPF_ALIGNMENT);
    00572     p->sf.version_major = hdr.version_major;
    00573     p->sf.version_minor = hdr.version_minor;
    00574 #ifdef PCAP_FDDIPAD
    00575     /* XXX padding only needed for kernel fcode */
    00576     pcap_fddipad = 0;
    00577 #endif
    00578
    00579     /*
    00580      * We interchanged the caplen and len fields at version 2.3,
    00581      * in order to match the bpf header layout.  But unfortunately
    00582      * some files were written with version 2.3 in their headers
    00583      * but without the interchanged fields.
    00584      *
    00585      * In addition, DG/UX tcpdump writes out files with a version
    00586      * number of 543.0, and with the caplen and len fields in the
    00587      * pre-2.3 order.
    00588      */
    00589     switch (hdr.version_major) {
    00590
    00591     case 2:
    00592         if (hdr.version_minor < 3)
    00593             p->sf.lengths_swapped = SWAPPED;
    00594         else if (hdr.version_minor == 3)
    00595             p->sf.lengths_swapped = MAYBE_SWAPPED;
    00596         else
    00597             p->sf.lengths_swapped = NOT_SWAPPED;
    00598         break;
    00599
    00600     case 543:
    00601         p->sf.lengths_swapped = SWAPPED;
    00602         break;
    00603
    00604     default:
    00605         p->sf.lengths_swapped = NOT_SWAPPED;
    00606         break;
    00607     }
    00608
    00609 #ifndef WIN32
    00610     /*
    00611      * You can do "select()" and "poll()" on plain files on most
    00612      * platforms, and should be able to do so on pipes.
    00613      *
    00614      * You can't do "select()" on anything other than sockets in
    00615      * Windows, so, on Win32 systems, we don't have "selectable_fd".
    00616      */
    00617     p->selectable_fd = fileno(fp);
    00618 #endif
    00619
    00620     p->read_op = pcap_offline_read;
    00621     p->setfilter_op = install_bpf_program;
    00622     p->set_datalink_op = NULL;  /* we don't support munging link-layer headers */
    00623     p->getnonblock_op = sf_getnonblock;
    00624     p->setnonblock_op = sf_setnonblock;
    00625     p->stats_op = sf_stats;
    00626     p->close_op = sf_close;
    00627
    00628     return (p);
    00629  bad:
    00630     if(fp)
    00631         fclose(fp);
    00632     free(p);
    00633     return (NULL);
    00634 }
    00635
    00636 /*
    00637  * Read sf_readfile and return the next packet.  Return the header in hdr
    00638  * and the contents in buf.  Return 0 on success, SFERR_EOF if there were
    00639  * no more packets, and SFERR_TRUNC if a partial packet was encountered.
    00640  */
    00641 static int
    00642 sf_next_packet(pcap_t *p, struct pcap_pkthdr *hdr, u_char *buf, u_int buflen)
    00643 {
    00644     struct pcap_sf_patched_pkthdr sf_hdr;
    00645     FILE *fp = p->sf.rfile;
    00646     size_t amt_read;
    00647     bpf_u_int32 t;
    00648
    00649     /*
    00650      * Read the packet header; the structure we use as a buffer
    00651      * is the longer structure for files generated by the patched
    00652      * libpcap, but if the file has the magic number for an
    00653      * unpatched libpcap we only read as many bytes as the regular
    00654      * header has.
    00655      */
    00656     amt_read = fread(&sf_hdr, 1, p->sf.hdrsize, fp);
    00657     if (amt_read != p->sf.hdrsize) {
    00658         if (ferror(fp)) {
    00659             snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
    00660                 "error reading dump file: %s",
    00661                 pcap_strerror(errno));
    00662             return (-1);
    00663         } else {
    00664             if (amt_read != 0) {
    00665                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
    00666                     "truncated dump file; tried to read %d header bytes, only got %lu",
    00667                     p->sf.hdrsize, (unsigned long)amt_read);
    00668                 return (-1);
    00669             }
    00670             /* EOF */
    00671             return (1);
    00672         }
    00673     }
    00674
    00675     if (p->sf.swapped) {
    00676         /* these were written in opposite byte order */
    00677         hdr->caplen = SWAPLONG(sf_hdr.caplen);
    00678         hdr->len = SWAPLONG(sf_hdr.len);
    00679         hdr->ts.tv_sec = SWAPLONG(sf_hdr.ts.tv_sec);
    00680         hdr->ts.tv_usec = SWAPLONG(sf_hdr.ts.tv_usec);
    00681     } else {
    00682         hdr->caplen = sf_hdr.caplen;
    00683         hdr->len = sf_hdr.len;
    00684         hdr->ts.tv_sec = sf_hdr.ts.tv_sec;
    00685         hdr->ts.tv_usec = sf_hdr.ts.tv_usec;
    00686     }
    00687     /* Swap the caplen and len fields, if necessary. */
    00688     switch (p->sf.lengths_swapped) {
    00689
    00690     case NOT_SWAPPED:
    00691         break;
    00692
    00693     case MAYBE_SWAPPED:
    00694         if (hdr->caplen <= hdr->len) {
    00695             /*
    00696              * The captured length is <= the actual length,
    00697              * so presumably they weren't swapped.
    00698              */
    00699             break;
    00700         }
    00701         /* FALLTHROUGH */
    00702
    00703     case SWAPPED:
    00704         t = hdr->caplen;
    00705         hdr->caplen = hdr->len;
    00706         hdr->len = t;
    00707         break;
    00708     }
    00709
    00710     if (hdr->caplen > buflen) {
    00711         /*
    00712          * This can happen due to Solaris 2.3 systems tripping
    00713          * over the BUFMOD problem and not setting the snapshot
    00714          * correctly in the savefile header.  If the caplen isn't
    00715          * grossly wrong, try to salvage.
    00716          */
    00717         static u_char *tp = NULL;
    00718         static size_t tsize = 0;
    00719
    00720         if (hdr->caplen > 65535) {
    00721             snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
    00722                 "bogus savefile header");
    00723             return (-1);
    00724         }
    00725
    00726         if (tsize < hdr->caplen) {
    00727             tsize = ((hdr->caplen + 1023) / 1024) * 1024;
    00728             if (tp != NULL)
    00729                 free((u_char *)tp);
    00730             tp = (u_char *)malloc(tsize);
    00731             if (tp == NULL) {
    00732                 tsize = 0;
    00733                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
    00734                     "BUFMOD hack malloc");
    00735                 return (-1);
    00736             }
    00737         }
    00738         amt_read = fread((char *)tp, 1, hdr->caplen, fp);
    00739         if (amt_read != hdr->caplen) {
    00740             if (ferror(fp)) {
    00741                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
    00742                     "error reading dump file: %s",
    00743                     pcap_strerror(errno));
    00744             } else {
    00745                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
    00746                     "truncated dump file; tried to read %u captured bytes, only got %lu",
    00747                     hdr->caplen, (unsigned long)amt_read);
    00748             }
    00749             return (-1);
    00750         }
    00751         /*
    00752          * We can only keep up to buflen bytes.  Since caplen > buflen
    00753          * is exactly how we got here, we know we can only keep the
    00754          * first buflen bytes and must drop the remainder.  Adjust
    00755          * caplen accordingly, so we don't get confused later as
    00756          * to how many bytes we have to play with.
    00757          */
    00758         hdr->caplen = buflen;
    00759         memcpy((char *)buf, (char *)tp, buflen);
    00760
    00761     } else {
    00762         /* read the packet itself */
    00763         amt_read = fread((char *)buf, 1, hdr->caplen, fp);
    00764         if (amt_read != hdr->caplen) {
    00765             if (ferror(fp)) {
    00766                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
    00767                     "error reading dump file: %s",
    00768                     pcap_strerror(errno));
    00769             } else {
    00770                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
    00771                     "truncated dump file; tried to read %u captured bytes, only got %lu",
    00772                     hdr->caplen, (unsigned long)amt_read);
    00773             }
    00774             return (-1);
    00775         }
    00776     }
    00777     return (0);
    00778 }
    00779
    00780 /*
    00781  * Print out packets stored in the file initialized by sf_read_init().
    00782  * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
    00783  */
    00784 int
    00785 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
    00786 {
    00787     struct bpf_insn *fcode = p->fcode.bf_insns;
    00788     int status = 0;
    00789     int n = 0;
    00790
    00791 #ifdef HAVE_REMOTE
    00792     static int samp_npkt;               // parameter needed for sampling, whtn '1 out of N' method has been requested
    00793     static struct timeval samp_time;    // parameter needed for sampling, whtn '1 every N ms' method has been requested
    00794 #endif /* HAVE_REMOTE */
    00795
    00796
    00797     while (status == 0) {
    00798         struct pcap_pkthdr h;
    00799
    00800         /*
    00801          * Has "pcap_breakloop()" been called?
    00802          * If so, return immediately - if we haven't read any
    00803          * packets, clear the flag and return -2 to indicate
    00804          * that we were told to break out of the loop, otherwise
    00805          * leave the flag set, so that the *next* call will break
    00806          * out of the loop without having read any packets, and
    00807          * return the number of packets we've processed so far.
    00808          */
    00809         if (p->break_loop) {
    00810             if (n == 0) {
    00811                 p->break_loop = 0;
    00812                 return (-2);
    00813             } else
    00814                 return (n);
    00815         }
    00816
    00817         status = sf_next_packet(p, &h, p->buffer, p->bufsize);
    00818         if (status) {
    00819             if (status == 1)
    00820                 return (0);
    00821             return (status);
    00822         }
    00823
    00824         if (fcode == NULL ||
    00825             bpf_filter(fcode, p->buffer, h.len, h.caplen)) {
    00826
    00827 #ifdef HAVE_REMOTE
    00828             if (p->rmt_samp.method == PCAP_SAMP_1_EVERY_N)
    00829             {
    00830                 samp_npkt= (samp_npkt + 1) % p->rmt_samp.value;
    00831
    00832                 // Discard all packets that are not '1 out of N'
    00833                 if (samp_npkt != 0)
    00834                     continue;
    00835             }
    00836
    00837             if (p->rmt_samp.method == PCAP_SAMP_FIRST_AFTER_N_MS)
    00838             {
    00839                 // Check if the timestamp of the arrived packet is smaller than our target time
    00840                 if ( (h.ts.tv_sec < samp_time.tv_sec) ||
    00841                         ( (h.ts.tv_sec == samp_time.tv_sec) && (h.ts.tv_usec < samp_time.tv_usec) ) )
    00842                     continue;
    00843
    00844                 // The arrived packet is suitable for being sent to the remote host
    00845                 // So, let's update the target time
    00846                 samp_time.tv_usec= h.ts.tv_usec + p->rmt_samp.value * 1000;
    00847                 if (samp_time.tv_usec > 1000000)
    00848                 {
    00849                     samp_time.tv_sec= h.ts.tv_sec + samp_time.tv_usec / 1000000;
    00850                     samp_time.tv_usec= samp_time.tv_usec % 1000000;
    00851                 }
    00852
    00853             }
    00854 #endif /* HAVE_REMOTE */
    00855
    00856             (*callback)(user, &h, p->buffer);
    00857             if (++n >= cnt && cnt > 0)
    00858                 break;
    00859         }
    00860     }
    00861     /*XXX this breaks semantics tcpslice expects */
    00862     return (n);
    00863 }
    00864
    00865 /*
    00866  * Output a packet to the initialized dump file.
    00867  */
    00868 void
    00869 pcap_dump(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
    00870 {
    00871     register FILE *f;
    00872     struct pcap_sf_pkthdr sf_hdr;
    00873
    00874     f = (FILE *)user;
    00875     sf_hdr.ts.tv_sec  = h->ts.tv_sec;
    00876     sf_hdr.ts.tv_usec = h->ts.tv_usec;
    00877     sf_hdr.caplen     = h->caplen;
    00878     sf_hdr.len        = h->len;
    00879     /* XXX we should check the return status */
    00880     (void)fwrite(&sf_hdr, sizeof(sf_hdr), 1, f);
    00881     (void)fwrite((char *)sp, h->caplen, 1, f);
    00882 }
    00883
    00884 /*
    00885  * Initialize so that sf_write() will output to the file named 'fname'.
    00886  */
    00887 pcap_dumper_t *
    00888 pcap_dump_open(pcap_t *p, const char *fname)
    00889 {
    00890     FILE *f;
    00891     int linktype;
    00892
    00893     linktype = dlt_to_linktype(p->linktype);
    00894     if (linktype == -1) {
    00895         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
    00896             "%s: link-layer type %d isn't supported in savefiles",
    00897             fname, linktype);
    00898         return (NULL);
    00899     }
    00900
    00901     if (fname[0] == '-' && fname[1] == '\0') {
    00902         f = stdout;
    00903 #ifdef WIN32
    00904         _setmode(_fileno(f), _O_BINARY);
    00905 #endif
    00906     } else {
    00907 #ifndef WIN32
    00908         f = fopen(fname, "w");
    00909 #else
    00910         f = fopen(fname, "wb");
    00911 #endif
    00912         if (f == NULL) {
    00913             snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: %s",
    00914                 fname, pcap_strerror(errno));
    00915             return (NULL);
    00916         }
    00917 #ifdef WIN32
    00918         setbuf(f, NULL);
    00919 #endif
    00920
    00921     }
    00922     (void)sf_write_header(f, linktype, p->tzoff, p->snapshot);
    00923     return ((pcap_dumper_t *)f);
    00924 }
    00925
    00926 FILE *
    00927 pcap_dump_file(pcap_dumper_t *p)
    00928 {
    00929     return ((FILE *)p);
    00930 }
    00931
    00932 int
    00933 pcap_dump_flush(pcap_dumper_t *p)
    00934 {
    00935
    00936     if (fflush((FILE *)p) == EOF)
    00937         return (-1);
    00938     else
    00939         return (0);
    00940 }
    00941
    00942 void
    00943 pcap_dump_close(pcap_dumper_t *p)
    00944 {
    00945
    00946 #ifdef notyet
    00947     if (ferror((FILE *)p))
    00948         return-an-error;
    00949     /* XXX should check return from fclose() too */
    00950 #endif
    00951     (void)fclose((FILE *)p);
    00952 }

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