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   1 /*
   2  * Copyright (c) 1994, 1995, 1996
   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 the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the Computer Systems
  16  *      Engineering Group at Lawrence Berkeley Laboratory.
  17  * 4. Neither the name of the University nor of the Laboratory may be used
  18  *    to endorse or promote products derived from this software without
  19  *    specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #ifndef pcap_int_h
  35 #define pcap_int_h
  36
  37 #include <pcap/pcap.h>
  38
  39 #ifdef __cplusplus
  40 extern "C" {
  41 #endif
  42
  43 #if defined(_WIN32)
  44   /*
  45    * Make sure Packet32.h doesn't define BPF structures that we've
  46    * probably already defined as a result of including <pcap/pcap.h>.
  47    */
  48   #define BPF_MAJOR_VERSION
  49   #include <Packet32.h>
  50   extern CRITICAL_SECTION g_PcapCompileCriticalSection;
  51
  52   /*
  53    * Non-API functions; don't export them.
  54    */
  55   #define PCAP_INTERNAL extern
  56 #elif defined(MSDOS)
  57   #include <fcntl.h>
  58   #include <io.h>
  59
  60   /* XXX - does this need special treatment? */
  61   #define PCAP_INTERNAL extern
  62 #else
  63   /*
  64    * Try to make stuff declared here not visible in the shared library.
  65    */
  66   #if __GNUC__ >= 4 || defined(__SUNPRO_C) && (__SUNPRO_C >= 0x590)
  67     /*
  68      * We have __attribute__((visibility()).
  69      */
  70     #define PCAP_INTERNAL       __attribute__((visibility("hidden")))
  71   #elif defined(__SUNPRO_C) && (__SUNPRO_C >= 0x550)
  72     /*
  73      * We don't have __attribute__((visibility()), but we do have
  74      * __hidden.
  75      */
  76     #define PCAP_INTERNAL       __hidden
  77   #else
  78     /*
  79      * We don't have either of them.
  80      */
  81     #define PCAP_INTERNAL       extern
  82   #endif
  83 #endif
  84
  85 #if (defined(_MSC_VER) && (_MSC_VER <= 1200)) /* we are compiling with Visual Studio 6, that doesn't support the LL suffix*/
  86
  87 /*
  88  * Swap byte ordering of unsigned long long timestamp on a big endian
  89  * machine.
  90  */
  91 #define SWAPLL(ull)  ((ull & 0xff00000000000000) >> 56) | \
  92                       ((ull & 0x00ff000000000000) >> 40) | \
  93                       ((ull & 0x0000ff0000000000) >> 24) | \
  94                       ((ull & 0x000000ff00000000) >> 8)  | \
  95                       ((ull & 0x00000000ff000000) << 8)  | \
  96                       ((ull & 0x0000000000ff0000) << 24) | \
  97                       ((ull & 0x000000000000ff00) << 40) | \
  98                       ((ull & 0x00000000000000ff) << 56)
  99
 100 #else /* A recent Visual studio compiler or not VC */
 101
 102 /*
 103  * Swap byte ordering of unsigned long long timestamp on a big endian
 104  * machine.
 105  */
 106 #define SWAPLL(ull)  ((ull & 0xff00000000000000LL) >> 56) | \
 107                       ((ull & 0x00ff000000000000LL) >> 40) | \
 108                       ((ull & 0x0000ff0000000000LL) >> 24) | \
 109                       ((ull & 0x000000ff00000000LL) >> 8)  | \
 110                       ((ull & 0x00000000ff000000LL) << 8)  | \
 111                       ((ull & 0x0000000000ff0000LL) << 24) | \
 112                       ((ull & 0x000000000000ff00LL) << 40) | \
 113                       ((ull & 0x00000000000000ffLL) << 56)
 114
 115 #endif /* _MSC_VER */
 116
 117 /*
 118  * Maximum snapshot length.
 119  *
 120  * Somewhat arbitrary, but chosen to be:
 121  *
 122  *    1) big enough for maximum-size Linux loopback packets (65549)
 123  *       and some USB packets captured with USBPcap:
 124  *
 125  *           http://desowin.org/usbpcap/
 126  *
 127  *       (> 131072, < 262144)
 128  *
 129  * and
 130  *
 131  *    2) small enough not to cause attempts to allocate huge amounts of
 132  *       memory; some applications might use the snapshot length in a
 133  *       savefile header to control the size of the buffer they allocate,
 134  *       so a size of, say, 2^31-1 might not work well.
 135  *
 136  * We don't enforce this in pcap_set_snaplen(), but we use it internally.
 137  */
 138 #define MAXIMUM_SNAPLEN         262144
 139
 140 struct pcap_opt {
 141         char    *source;
 142         int     timeout;        /* timeout for buffering */
 143         int     buffer_size;
 144         int     promisc;
 145         int     rfmon;          /* monitor mode */
 146         int     immediate;      /* immediate mode - deliver packets as soon as they arrive */
 147         int     tstamp_type;
 148         int     tstamp_precision;
 149 };
 150
 151 typedef int     (*activate_op_t)(pcap_t *);
 152 typedef int     (*can_set_rfmon_op_t)(pcap_t *);
 153 typedef int     (*read_op_t)(pcap_t *, int cnt, pcap_handler, u_char *);
 154 typedef int     (*inject_op_t)(pcap_t *, const void *, size_t);
 155 typedef int     (*setfilter_op_t)(pcap_t *, struct bpf_program *);
 156 typedef int     (*setdirection_op_t)(pcap_t *, pcap_direction_t);
 157 typedef int     (*set_datalink_op_t)(pcap_t *, int);
 158 typedef int     (*getnonblock_op_t)(pcap_t *, char *);
 159 typedef int     (*setnonblock_op_t)(pcap_t *, int, char *);
 160 typedef int     (*stats_op_t)(pcap_t *, struct pcap_stat *);
 161 #ifdef _WIN32
 162 typedef struct pcap_stat *(*stats_ex_op_t)(pcap_t *, int *);
 163 typedef int     (*setbuff_op_t)(pcap_t *, int);
 164 typedef int     (*setmode_op_t)(pcap_t *, int);
 165 typedef int     (*setmintocopy_op_t)(pcap_t *, int);
 166 typedef HANDLE  (*getevent_op_t)(pcap_t *);
 167 typedef int     (*oid_get_request_op_t)(pcap_t *, bpf_u_int32, void *, size_t);
 168 typedef int     (*oid_set_request_op_t)(pcap_t *, bpf_u_int32, const void *, size_t);
 169 typedef u_int   (*sendqueue_transmit_op_t)(pcap_t *, pcap_send_queue *, int);
 170 typedef int     (*setuserbuffer_op_t)(pcap_t *, int);
 171 typedef int     (*live_dump_op_t)(pcap_t *, char *, int, int);
 172 typedef int     (*live_dump_ended_op_t)(pcap_t *, int);
 173 typedef PAirpcapHandle  (*get_airpcap_handle_op_t)(pcap_t *);
 174 #endif
 175 typedef void    (*cleanup_op_t)(pcap_t *);
 176
 177 /*
 178  * We put all the stuff used in the read code path at the beginning,
 179  * to try to keep it together in the same cache line or lines.
 180  */
 181 struct pcap {
 182         /*
 183          * Method to call to read packets on a live capture.
 184          */
 185         read_op_t read_op;
 186
 187         /*
 188          * Method to call to read packets from a savefile.
 189          */
 190         int (*next_packet_op)(pcap_t *, struct pcap_pkthdr *, u_char **);
 191
 192 #ifdef _WIN32
 193         ADAPTER *adapter;
 194 #else
 195         int fd;
 196         int selectable_fd;
 197 #endif /* _WIN32 */
 198
 199         /*
 200          * Read buffer.
 201          */
 202         int bufsize;
 203         void *buffer;
 204         u_char *bp;
 205         int cc;
 206
 207         int break_loop;         /* flag set to force break from packet-reading loop */
 208
 209         void *priv;             /* private data for methods */
 210
 211         int swapped;
 212         FILE *rfile;            /* null if live capture, non-null if savefile */
 213         int fddipad;
 214         struct pcap *next;      /* list of open pcaps that need stuff cleared on close */
 215
 216         /*
 217          * File version number; meaningful only for a savefile, but we
 218          * keep it here so that apps that (mistakenly) ask for the
 219          * version numbers will get the same zero values that they
 220          * always did.
 221          */
 222         int version_major;
 223         int version_minor;
 224
 225         int snapshot;
 226         int linktype;           /* Network linktype */
 227         int linktype_ext;       /* Extended information stored in the linktype field of a file */
 228         int tzoff;              /* timezone offset */
 229         int offset;             /* offset for proper alignment */
 230         int activated;          /* true if the capture is really started */
 231         int oldstyle;           /* if we're opening with pcap_open_live() */
 232
 233         struct pcap_opt opt;
 234
 235         /*
 236          * Place holder for pcap_next().
 237          */
 238         u_char *pkt;
 239
 240 #ifdef _WIN32
 241         struct pcap_stat stat;          /* used for pcap_stats_ex() */
 242 #endif
 243
 244         /* We're accepting only packets in this direction/these directions. */
 245         pcap_direction_t direction;
 246
 247         /*
 248          * Flags to affect BPF code generation.
 249          */
 250         int bpf_codegen_flags;
 251
 252         /*
 253          * Placeholder for filter code if bpf not in kernel.
 254          */
 255         struct bpf_program fcode;
 256
 257         char errbuf[PCAP_ERRBUF_SIZE + 1];
 258         int dlt_count;
 259         u_int *dlt_list;
 260         int tstamp_type_count;
 261         u_int *tstamp_type_list;
 262         int tstamp_precision_count;
 263         u_int *tstamp_precision_list;
 264
 265         struct pcap_pkthdr pcap_header; /* This is needed for the pcap_next_ex() to work */
 266
 267         /*
 268          * More methods.
 269          */
 270         activate_op_t activate_op;
 271         can_set_rfmon_op_t can_set_rfmon_op;
 272         inject_op_t inject_op;
 273         setfilter_op_t setfilter_op;
 274         setdirection_op_t setdirection_op;
 275         set_datalink_op_t set_datalink_op;
 276         getnonblock_op_t getnonblock_op;
 277         setnonblock_op_t setnonblock_op;
 278         stats_op_t stats_op;
 279
 280         /*
 281          * Routine to use as callback for pcap_next()/pcap_next_ex().
 282          */
 283         pcap_handler oneshot_callback;
 284
 285 #ifdef _WIN32
 286         /*
 287          * These are, at least currently, specific to the Win32 NPF
 288          * driver.
 289          */
 290         stats_ex_op_t stats_ex_op;
 291         setbuff_op_t setbuff_op;
 292         setmode_op_t setmode_op;
 293         setmintocopy_op_t setmintocopy_op;
 294         getevent_op_t getevent_op;
 295         oid_get_request_op_t oid_get_request_op;
 296         oid_set_request_op_t oid_set_request_op;
 297         sendqueue_transmit_op_t sendqueue_transmit_op;
 298         setuserbuffer_op_t setuserbuffer_op;
 299         live_dump_op_t live_dump_op;
 300         live_dump_ended_op_t live_dump_ended_op;
 301         get_airpcap_handle_op_t get_airpcap_handle_op;
 302 #endif
 303         cleanup_op_t cleanup_op;
 304 };
 305
 306 /*
 307  * BPF code generation flags.
 308  */
 309 #define BPF_SPECIAL_VLAN_HANDLING       0x00000001      /* special VLAN handling for Linux */
 310
 311 /*
 312  * This is a timeval as stored in a savefile.
 313  * It has to use the same types everywhere, independent of the actual
 314  * `struct timeval'; `struct timeval' has 32-bit tv_sec values on some
 315  * platforms and 64-bit tv_sec values on other platforms, and writing
 316  * out native `struct timeval' values would mean files could only be
 317  * read on systems with the same tv_sec size as the system on which
 318  * the file was written.
 319  */
 320
 321 struct pcap_timeval {
 322     bpf_int32 tv_sec;           /* seconds */
 323     bpf_int32 tv_usec;          /* microseconds */
 324 };
 325
 326 /*
 327  * This is a `pcap_pkthdr' as actually stored in a savefile.
 328  *
 329  * Do not change the format of this structure, in any way (this includes
 330  * changes that only affect the length of fields in this structure),
 331  * and do not make the time stamp anything other than seconds and
 332  * microseconds (e.g., seconds and nanoseconds).  Instead:
 333  *
 334  *      introduce a new structure for the new format;
 335  *
 336  *      send mail to "tcpdump-workers@lists.tcpdump.org", requesting
 337  *      a new magic number for your new capture file format, and, when
 338  *      you get the new magic number, put it in "savefile.c";
 339  *
 340  *      use that magic number for save files with the changed record
 341  *      header;
 342  *
 343  *      make the code in "savefile.c" capable of reading files with
 344  *      the old record header as well as files with the new record header
 345  *      (using the magic number to determine the header format).
 346  *
 347  * Then supply the changes by forking the branch at
 348  *
 349  *      https://github.com/the-tcpdump-group/libpcap/issues
 350  *
 351  * and issuing a pull request, so that future versions of libpcap and
 352  * programs that use it (such as tcpdump) will be able to read your new
 353  * capture file format.
 354  */
 355
 356 struct pcap_sf_pkthdr {
 357     struct pcap_timeval ts;     /* time stamp */
 358     bpf_u_int32 caplen;         /* length of portion present */
 359     bpf_u_int32 len;            /* length this packet (off wire) */
 360 };
 361
 362 /*
 363  * How a `pcap_pkthdr' is actually stored in savefiles written
 364  * by some patched versions of libpcap (e.g. the ones in Red
 365  * Hat Linux 6.1 and 6.2).
 366  *
 367  * Do not change the format of this structure, in any way (this includes
 368  * changes that only affect the length of fields in this structure).
 369  * Instead, introduce a new structure, as per the above.
 370  */
 371
 372 struct pcap_sf_patched_pkthdr {
 373     struct pcap_timeval ts;     /* time stamp */
 374     bpf_u_int32 caplen;         /* length of portion present */
 375     bpf_u_int32 len;            /* length this packet (off wire) */
 376     int         index;
 377     unsigned short protocol;
 378     unsigned char pkt_type;
 379 };
 380
 381 /*
 382  * User data structure for the one-shot callback used for pcap_next()
 383  * and pcap_next_ex().
 384  */
 385 struct oneshot_userdata {
 386         struct pcap_pkthdr *hdr;
 387         const u_char **pkt;
 388         pcap_t *pd;
 389 };
 390
 391 #ifndef min
 392 #define min(a, b) ((a) > (b) ? (b) : (a))
 393 #endif
 394
 395 PCAP_INTERNAL int       pcap_offline_read(pcap_t *, int, pcap_handler, u_char *);
 396
 397 #ifndef HAVE_STRLCPY
 398 #define strlcpy(x, y, z) \
 399         (strncpy((x), (y), (z)), \
 400          ((z) <= 0 ? 0 : ((x)[(z) - 1] = '\0')), \
 401          strlen((y)))
 402 #endif
 403
 404 #include <stdarg.h>
 405
 406 /*
 407  * For flagging arguments as format strings in MSVC.
 408  */
 409 #if _MSC_VER >= 1400
 410  #include <sal.h>
 411  #if _MSC_VER > 1400
 412   #define FORMAT_STRING(p) _Printf_format_string_ p
 413  #else
 414   #define FORMAT_STRING(p) __format_string p
 415  #endif
 416 #else
 417  #define FORMAT_STRING(p) p
 418 #endif
 419
 420 /*
 421  * On Windows, snprintf(), with that name and with C99 behavior - i.e.,
 422  * guaranteeing that the formatted string is null-terminated - didn't
 423  * appear until Visual Studio 2015.  Prior to that, the C runtime had
 424  * only _snprintf(), which *doesn't* guarantee that the string is
 425  * null-terminated if it is truncated due to the buffer being too
 426  * small.  We therefore can't just define snprintf to be _snprintf
 427  * and define vsnprintf to be _vsnprintf, as we're relying on null-
 428  * termination of strings in all cases.
 429  *
 430  * We also want to allow this to be built with versions of Visual Studio
 431  * prior to VS 2015, so we can't rely on snprintf() being present.
 432  *
 433  * And we want to make sure that, if we support plugins in the future,
 434  * a routine with C99 snprintf() behavior will be available to them.
 435  * We also don't want it to collide with the C library snprintf() if
 436  * there is one.
 437  *
 438  * So we make pcap_snprintf() and pcap_vsnprintf() available, either by
 439  * #defining them to be snprintf or vsnprintf, respectively, or by
 440  * defining our own versions and exporting them.
 441  */
 442 #ifdef HAVE_SNPRINTF
 443 #define pcap_snprintf snprintf
 444 #else
 445 PCAP_INTERNAL int pcap_snprintf(char *, size_t, FORMAT_STRING(const char *), ...);
 446 #endif
 447
 448 #ifdef HAVE_VSNPRINTF
 449 #define pcap_vsnprintf vsnprintf
 450 #else
 451 PCAP_INTERNAL extern int pcap_vsnprintf(char *, size_t, const char *, va_list ap);
 452 #endif
 453
 454 /*
 455  * Does the packet count argument to a module's read routine say
 456  * "supply packets until you run out of packets"?
 457  */
 458 #define PACKET_COUNT_IS_UNLIMITED(count)        ((count) <= 0)
 459
 460 /*
 461  * Routines that most pcap implementations can use for non-blocking mode.
 462  */
 463 #if !defined(_WIN32) && !defined(MSDOS)
 464 PCAP_INTERNAL int       pcap_getnonblock_fd(pcap_t *, char *);
 465 PCAP_INTERNAL int       pcap_setnonblock_fd(pcap_t *p, int, char *);
 466 #endif
 467
 468 /*
 469  * Internal interfaces for "pcap_create()".
 470  *
 471  * "pcap_create_interface()" is the routine to do a pcap_create on
 472  * a regular network interface.  There are multiple implementations
 473  * of this, one for each platform type (Linux, BPF, DLPI, etc.),
 474  * with the one used chosen by the configure script.
 475  *
 476  * "pcap_create_common()" allocates and fills in a pcap_t, for use
 477  * by pcap_create routines.
 478  */
 479 PCAP_INTERNAL pcap_t    *pcap_create_interface(const char *, char *);
 480 PCAP_INTERNAL pcap_t    *pcap_create_common(const char *, char *, size_t);
 481 PCAP_INTERNAL int       pcap_do_addexit(pcap_t *);
 482 PCAP_INTERNAL void      pcap_add_to_pcaps_to_close(pcap_t *);
 483 PCAP_INTERNAL void      pcap_remove_from_pcaps_to_close(pcap_t *);
 484 PCAP_INTERNAL void      pcap_cleanup_live_common(pcap_t *);
 485 PCAP_INTERNAL int       pcap_check_activated(pcap_t *);
 486
 487 /*
 488  * Internal interfaces for "pcap_findalldevs()".
 489  *
 490  * "pcap_findalldevs_interfaces()" finds interfaces using the
 491  * "standard" mechanisms (SIOCGIFCONF, "getifaddrs()", etc.).
 492  *
 493  * "pcap_platform_finddevs()" is a platform-dependent routine to
 494  * add devices not found by the "standard" mechanisms.
 495  *
 496  * "pcap_add_if()" adds an interface to the list of interfaces, for
 497  * use by various "find interfaces" routines.
 498  */
 499 PCAP_INTERNAL int       pcap_findalldevs_interfaces(pcap_if_t **, char *);
 500 PCAP_INTERNAL int       pcap_platform_finddevs(pcap_if_t **, char *);
 501 PCAP_INTERNAL int       add_addr_to_iflist(pcap_if_t **, const char *, u_int, struct sockaddr *,
 502             size_t, struct sockaddr *, size_t, struct sockaddr *, size_t,
 503             struct sockaddr *, size_t, char *);
 504 PCAP_INTERNAL int       add_addr_to_dev(pcap_if_t *, struct sockaddr *, size_t,
 505             struct sockaddr *, size_t, struct sockaddr *, size_t,
 506             struct sockaddr *dstaddr, size_t, char *errbuf);
 507 PCAP_INTERNAL int       pcap_add_if(pcap_if_t **, const char *, u_int, const char *, char *);
 508 PCAP_INTERNAL struct sockaddr *dup_sockaddr(struct sockaddr *, size_t);
 509 PCAP_INTERNAL int       add_or_find_if(pcap_if_t **, pcap_if_t **, const char *, u_int,
 510             const char *, char *);
 511
 512 /*
 513  * Internal interfaces for "pcap_open_offline()".
 514  *
 515  * "pcap_open_offline_common()" allocates and fills in a pcap_t, for use
 516  * by pcap_open_offline routines.
 517  *
 518  * "sf_cleanup()" closes the file handle associated with a pcap_t, if
 519  * appropriate, and frees all data common to all modules for handling
 520  * savefile types.
 521  */
 522 PCAP_INTERNAL pcap_t    *pcap_open_offline_common(char *ebuf, size_t size);
 523 PCAP_INTERNAL void      sf_cleanup(pcap_t *p);
 524
 525 /*
 526  * Internal interfaces for both "pcap_create()" and routines that
 527  * open savefiles.
 528  *
 529  * "pcap_oneshot()" is the standard one-shot callback for "pcap_next()"
 530  * and "pcap_next_ex()".
 531  */
 532 PCAP_INTERNAL void      pcap_oneshot(u_char *, const struct pcap_pkthdr *, const u_char *);
 533
 534 #ifdef _WIN32
 535 PCAP_INTERNAL void      pcap_win32_err_to_str(DWORD, char *);
 536 #endif
 537
 538 PCAP_INTERNAL int       install_bpf_program(pcap_t *, struct bpf_program *);
 539
 540 PCAP_INTERNAL int       pcap_strcasecmp(const char *, const char *);
 541
 542 #ifdef __cplusplus
 543 }
 544 #endif
 545
 546 #endif