The Tcpdump Group git mirrors - libpcap/blob - pcap-int.h

   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 <signal.h>
  38
  39 #include <pcap/pcap.h>
  40
  41 #include "varattrs.h"
  42 #include "fmtutils.h"
  43
  44 /*
  45  * Version string.
  46  * Uses PACKAGE_VERSION from config.h.
  47  */
  48 #define PCAP_VERSION_STRING "libpcap version " PACKAGE_VERSION
  49
  50 #ifdef __cplusplus
  51 extern "C" {
  52 #endif
  53
  54 #ifdef MSDOS
  55   #include <fcntl.h>
  56   #include <io.h>
  57 #endif
  58
  59 /*
  60  * Swap byte ordering of unsigned long long timestamp on a big endian
  61  * machine.
  62  */
  63 #define SWAPLL(ull)  ((ull & 0xff00000000000000ULL) >> 56) | \
  64                       ((ull & 0x00ff000000000000ULL) >> 40) | \
  65                       ((ull & 0x0000ff0000000000ULL) >> 24) | \
  66                       ((ull & 0x000000ff00000000ULL) >> 8)  | \
  67                       ((ull & 0x00000000ff000000ULL) << 8)  | \
  68                       ((ull & 0x0000000000ff0000ULL) << 24) | \
  69                       ((ull & 0x000000000000ff00ULL) << 40) | \
  70                       ((ull & 0x00000000000000ffULL) << 56)
  71
  72 /*
  73  * Maximum snapshot length.
  74  *
  75  * Somewhat arbitrary, but chosen to be:
  76  *
  77  *    1) big enough for maximum-size Linux loopback packets (65549)
  78  *       and some USB packets captured with USBPcap:
  79  *
  80  *           http://desowin.org/usbpcap/
  81  *
  82  *       (> 131072, < 262144)
  83  *
  84  * and
  85  *
  86  *    2) small enough not to cause attempts to allocate huge amounts of
  87  *       memory; some applications might use the snapshot length in a
  88  *       savefile header to control the size of the buffer they allocate,
  89  *       so a size of, say, 2^31-1 might not work well.
  90  *
  91  * We don't enforce this in pcap_set_snaplen(), but we use it internally.
  92  */
  93 #define MAXIMUM_SNAPLEN         262144
  94
  95 struct pcap_opt {
  96         char    *device;
  97         int     timeout;        /* timeout for buffering */
  98         u_int   buffer_size;
  99         int     promisc;
 100         int     rfmon;          /* monitor mode */
 101         int     immediate;      /* immediate mode - deliver packets as soon as they arrive */
 102         int     nonblock;       /* non-blocking mode - don't wait for packets to be delivered, return "no packets available" */
 103         int     tstamp_type;
 104         int     tstamp_precision;
 105
 106         /*
 107          * Platform-dependent options.
 108          */
 109 #ifdef __linux__
 110         int     protocol;       /* protocol to use when creating PF_PACKET socket */
 111 #endif
 112 #ifdef _WIN32
 113         int     nocapture_local;/* disable NPF loopback */
 114 #endif
 115 };
 116
 117 typedef int     (*activate_op_t)(pcap_t *);
 118 typedef int     (*can_set_rfmon_op_t)(pcap_t *);
 119 typedef int     (*read_op_t)(pcap_t *, int cnt, pcap_handler, u_char *);
 120 typedef int     (*next_packet_op_t)(pcap_t *, struct pcap_pkthdr *, u_char **);
 121 typedef int     (*inject_op_t)(pcap_t *, const void *, size_t);
 122 typedef void    (*save_current_filter_op_t)(pcap_t *, const char *);
 123 typedef int     (*setfilter_op_t)(pcap_t *, struct bpf_program *);
 124 typedef int     (*setdirection_op_t)(pcap_t *, pcap_direction_t);
 125 typedef int     (*set_datalink_op_t)(pcap_t *, int);
 126 typedef int     (*getnonblock_op_t)(pcap_t *);
 127 typedef int     (*setnonblock_op_t)(pcap_t *, int);
 128 typedef int     (*stats_op_t)(pcap_t *, struct pcap_stat *);
 129 #ifdef _WIN32
 130 typedef struct pcap_stat *(*stats_ex_op_t)(pcap_t *, int *);
 131 typedef int     (*setbuff_op_t)(pcap_t *, int);
 132 typedef int     (*setmode_op_t)(pcap_t *, int);
 133 typedef int     (*setmintocopy_op_t)(pcap_t *, int);
 134 typedef HANDLE  (*getevent_op_t)(pcap_t *);
 135 typedef int     (*oid_get_request_op_t)(pcap_t *, bpf_u_int32, void *, size_t *);
 136 typedef int     (*oid_set_request_op_t)(pcap_t *, bpf_u_int32, const void *, size_t *);
 137 typedef u_int   (*sendqueue_transmit_op_t)(pcap_t *, pcap_send_queue *, int);
 138 typedef int     (*setuserbuffer_op_t)(pcap_t *, int);
 139 typedef int     (*live_dump_op_t)(pcap_t *, char *, int, int);
 140 typedef int     (*live_dump_ended_op_t)(pcap_t *, int);
 141 typedef PAirpcapHandle  (*get_airpcap_handle_op_t)(pcap_t *);
 142 #endif
 143 typedef void    (*cleanup_op_t)(pcap_t *);
 144
 145 /*
 146  * We put all the stuff used in the read code path at the beginning,
 147  * to try to keep it together in the same cache line or lines.
 148  */
 149 struct pcap {
 150         /*
 151          * Method to call to read packets on a live capture.
 152          */
 153         read_op_t read_op;
 154
 155         /*
 156          * Method to call to read the next packet from a savefile.
 157          */
 158         next_packet_op_t next_packet_op;
 159
 160 #ifdef _WIN32
 161         HANDLE handle;
 162 #else
 163         int fd;
 164         int selectable_fd;
 165 #endif /* _WIN32 */
 166
 167         /*
 168          * Read buffer.
 169          */
 170         u_int bufsize;
 171         void *buffer;
 172         u_char *bp;
 173         int cc;
 174
 175         sig_atomic_t break_loop; /* flag set to force break from packet-reading loop */
 176
 177         void *priv;             /* private data for methods */
 178
 179 #ifdef ENABLE_REMOTE
 180         struct pcap_samp rmt_samp;      /* parameters related to the sampling process. */
 181 #endif
 182
 183         int swapped;
 184         FILE *rfile;            /* null if live capture, non-null if savefile */
 185         u_int fddipad;
 186         struct pcap *next;      /* list of open pcaps that need stuff cleared on close */
 187
 188         /*
 189          * File version number; meaningful only for a savefile, but we
 190          * keep it here so that apps that (mistakenly) ask for the
 191          * version numbers will get the same zero values that they
 192          * always did.
 193          */
 194         int version_major;
 195         int version_minor;
 196
 197         int snapshot;
 198         int linktype;           /* Network linktype */
 199         int linktype_ext;       /* Extended information stored in the linktype field of a file */
 200         int tzoff;              /* timezone offset */
 201         int offset;             /* offset for proper alignment */
 202         int activated;          /* true if the capture is really started */
 203         int oldstyle;           /* if we're opening with pcap_open_live() */
 204
 205         struct pcap_opt opt;
 206
 207         /*
 208          * Place holder for pcap_next().
 209          */
 210         u_char *pkt;
 211
 212 #ifdef _WIN32
 213         struct pcap_stat stat;          /* used for pcap_stats_ex() */
 214 #endif
 215
 216         /* We're accepting only packets in this direction/these directions. */
 217         pcap_direction_t direction;
 218
 219         /*
 220          * Flags to affect BPF code generation.
 221          */
 222         int bpf_codegen_flags;
 223
 224         /*
 225          * Placeholder for filter code if bpf not in kernel.
 226          */
 227         struct bpf_program fcode;
 228
 229         char errbuf[PCAP_ERRBUF_SIZE + 1];
 230         int dlt_count;
 231         u_int *dlt_list;
 232         int tstamp_type_count;
 233         u_int *tstamp_type_list;
 234         int tstamp_precision_count;
 235         u_int *tstamp_precision_list;
 236
 237         struct pcap_pkthdr pcap_header; /* This is needed for the pcap_next_ex() to work */
 238
 239         /*
 240          * More methods.
 241          */
 242         activate_op_t activate_op;
 243         can_set_rfmon_op_t can_set_rfmon_op;
 244         inject_op_t inject_op;
 245         save_current_filter_op_t save_current_filter_op;
 246         setfilter_op_t setfilter_op;
 247         setdirection_op_t setdirection_op;
 248         set_datalink_op_t set_datalink_op;
 249         getnonblock_op_t getnonblock_op;
 250         setnonblock_op_t setnonblock_op;
 251         stats_op_t stats_op;
 252
 253         /*
 254          * Routine to use as callback for pcap_next()/pcap_next_ex().
 255          */
 256         pcap_handler oneshot_callback;
 257
 258 #ifdef _WIN32
 259         /*
 260          * These are, at least currently, specific to the Win32 NPF
 261          * driver.
 262          */
 263         stats_ex_op_t stats_ex_op;
 264         setbuff_op_t setbuff_op;
 265         setmode_op_t setmode_op;
 266         setmintocopy_op_t setmintocopy_op;
 267         getevent_op_t getevent_op;
 268         oid_get_request_op_t oid_get_request_op;
 269         oid_set_request_op_t oid_set_request_op;
 270         sendqueue_transmit_op_t sendqueue_transmit_op;
 271         setuserbuffer_op_t setuserbuffer_op;
 272         live_dump_op_t live_dump_op;
 273         live_dump_ended_op_t live_dump_ended_op;
 274         get_airpcap_handle_op_t get_airpcap_handle_op;
 275 #endif
 276         cleanup_op_t cleanup_op;
 277 };
 278
 279 /*
 280  * BPF code generation flags.
 281  */
 282 #define BPF_SPECIAL_VLAN_HANDLING       0x00000001      /* special VLAN handling for Linux */
 283
 284 /*
 285  * This is a timeval as stored in a savefile.
 286  * It has to use the same types everywhere, independent of the actual
 287  * `struct timeval'; `struct timeval' has 32-bit tv_sec values on some
 288  * platforms and 64-bit tv_sec values on other platforms, and writing
 289  * out native `struct timeval' values would mean files could only be
 290  * read on systems with the same tv_sec size as the system on which
 291  * the file was written.
 292  */
 293
 294 struct pcap_timeval {
 295     bpf_int32 tv_sec;           /* seconds */
 296     bpf_int32 tv_usec;          /* microseconds */
 297 };
 298
 299 /*
 300  * This is a `pcap_pkthdr' as actually stored in a savefile.
 301  *
 302  * Do not change the format of this structure, in any way (this includes
 303  * changes that only affect the length of fields in this structure),
 304  * and do not make the time stamp anything other than seconds and
 305  * microseconds (e.g., seconds and nanoseconds).  Instead:
 306  *
 307  *      introduce a new structure for the new format;
 308  *
 309  *      send mail to "tcpdump-workers@lists.tcpdump.org", requesting
 310  *      a new magic number for your new capture file format, and, when
 311  *      you get the new magic number, put it in "savefile.c";
 312  *
 313  *      use that magic number for save files with the changed record
 314  *      header;
 315  *
 316  *      make the code in "savefile.c" capable of reading files with
 317  *      the old record header as well as files with the new record header
 318  *      (using the magic number to determine the header format).
 319  *
 320  * Then supply the changes by forking the branch at
 321  *
 322  *      https://github.com/the-tcpdump-group/libpcap/issues
 323  *
 324  * and issuing a pull request, so that future versions of libpcap and
 325  * programs that use it (such as tcpdump) will be able to read your new
 326  * capture file format.
 327  */
 328
 329 struct pcap_sf_pkthdr {
 330     struct pcap_timeval ts;     /* time stamp */
 331     bpf_u_int32 caplen;         /* length of portion present */
 332     bpf_u_int32 len;            /* length this packet (off wire) */
 333 };
 334
 335 /*
 336  * How a `pcap_pkthdr' is actually stored in savefiles written
 337  * by some patched versions of libpcap (e.g. the ones in Red
 338  * Hat Linux 6.1 and 6.2).
 339  *
 340  * Do not change the format of this structure, in any way (this includes
 341  * changes that only affect the length of fields in this structure).
 342  * Instead, introduce a new structure, as per the above.
 343  */
 344
 345 struct pcap_sf_patched_pkthdr {
 346     struct pcap_timeval ts;     /* time stamp */
 347     bpf_u_int32 caplen;         /* length of portion present */
 348     bpf_u_int32 len;            /* length this packet (off wire) */
 349     int         index;
 350     unsigned short protocol;
 351     unsigned char pkt_type;
 352 };
 353
 354 /*
 355  * User data structure for the one-shot callback used for pcap_next()
 356  * and pcap_next_ex().
 357  */
 358 struct oneshot_userdata {
 359         struct pcap_pkthdr *hdr;
 360         const u_char **pkt;
 361         pcap_t *pd;
 362 };
 363
 364 #ifndef min
 365 #define min(a, b) ((a) > (b) ? (b) : (a))
 366 #endif
 367
 368 int     pcap_offline_read(pcap_t *, int, pcap_handler, u_char *);
 369
 370 #include <stdarg.h>
 371
 372 #include "portability.h"
 373
 374 /*
 375  * Does the packet count argument to a module's read routine say
 376  * "supply packets until you run out of packets"?
 377  */
 378 #define PACKET_COUNT_IS_UNLIMITED(count)        ((count) <= 0)
 379
 380 /*
 381  * Routines that most pcap implementations can use for non-blocking mode.
 382  */
 383 #if !defined(_WIN32) && !defined(MSDOS)
 384 int     pcap_getnonblock_fd(pcap_t *);
 385 int     pcap_setnonblock_fd(pcap_t *p, int);
 386 #endif
 387
 388 /*
 389  * Internal interfaces for "pcap_create()".
 390  *
 391  * "pcap_create_interface()" is the routine to do a pcap_create on
 392  * a regular network interface.  There are multiple implementations
 393  * of this, one for each platform type (Linux, BPF, DLPI, etc.),
 394  * with the one used chosen by the configure script.
 395  *
 396  * "pcap_create_common()" allocates and fills in a pcap_t, for use
 397  * by pcap_create routines.
 398  */
 399 pcap_t  *pcap_create_interface(const char *, char *);
 400 pcap_t  *pcap_create_common(char *, size_t);
 401 int     pcap_do_addexit(pcap_t *);
 402 void    pcap_add_to_pcaps_to_close(pcap_t *);
 403 void    pcap_remove_from_pcaps_to_close(pcap_t *);
 404 void    pcap_cleanup_live_common(pcap_t *);
 405 int     pcap_check_activated(pcap_t *);
 406
 407 /*
 408  * Internal interfaces for "pcap_findalldevs()".
 409  *
 410  * A pcap_if_list_t * is a reference to a list of devices.
 411  *
 412  * "pcap_platform_finddevs()" is the platform-dependent routine to
 413  * find local network interfaces.
 414  *
 415  * "pcap_findalldevs_interfaces()" is a helper to find those interfaces
 416  * using the "standard" mechanisms (SIOCGIFCONF, "getifaddrs()", etc.).
 417  *
 418  * "add_dev()" adds an entry to a pcap_if_list_t.
 419  *
 420  * "find_dev()" tries to find a device, by name, in a pcap_if_list_t.
 421  *
 422  * "find_or_add_dev()" checks whether a device is already in a pcap_if_list_t
 423  * and, if not, adds an entry for it.
 424  */
 425 struct pcap_if_list;
 426 typedef struct pcap_if_list pcap_if_list_t;
 427 int     pcap_platform_finddevs(pcap_if_list_t *, char *);
 428 #if !defined(_WIN32) && !defined(MSDOS)
 429 int     pcap_findalldevs_interfaces(pcap_if_list_t *, char *,
 430             int (*)(const char *));
 431 #endif
 432 pcap_if_t *find_or_add_dev(pcap_if_list_t *, const char *, bpf_u_int32,
 433             const char *, char *);
 434 pcap_if_t *find_dev(pcap_if_list_t *, const char *);
 435 pcap_if_t *add_dev(pcap_if_list_t *, const char *, bpf_u_int32, const char *,
 436             char *);
 437 int     add_addr_to_dev(pcap_if_t *, struct sockaddr *, size_t,
 438             struct sockaddr *, size_t, struct sockaddr *, size_t,
 439             struct sockaddr *dstaddr, size_t, char *errbuf);
 440 #ifndef _WIN32
 441 pcap_if_t *find_or_add_if(pcap_if_list_t *, const char *, bpf_u_int32,
 442             char *);
 443 int     add_addr_to_if(pcap_if_list_t *, const char *, bpf_u_int32,
 444             struct sockaddr *, size_t, struct sockaddr *, size_t,
 445             struct sockaddr *, size_t, struct sockaddr *, size_t, char *);
 446 #endif
 447
 448 /*
 449  * Internal interfaces for "pcap_open_offline()".
 450  *
 451  * "pcap_open_offline_common()" allocates and fills in a pcap_t, for use
 452  * by pcap_open_offline routines.
 453  *
 454  * "sf_cleanup()" closes the file handle associated with a pcap_t, if
 455  * appropriate, and frees all data common to all modules for handling
 456  * savefile types.
 457  */
 458 pcap_t  *pcap_open_offline_common(char *ebuf, size_t size);
 459 void    sf_cleanup(pcap_t *p);
 460
 461 /*
 462  * Internal interfaces for both "pcap_create()" and routines that
 463  * open savefiles.
 464  *
 465  * "pcap_oneshot()" is the standard one-shot callback for "pcap_next()"
 466  * and "pcap_next_ex()".
 467  */
 468 void    pcap_oneshot(u_char *, const struct pcap_pkthdr *, const u_char *);
 469
 470 #ifdef _WIN32
 471 void    pcap_win32_err_to_str(DWORD, char *);
 472 #endif
 473
 474 int     install_bpf_program(pcap_t *, struct bpf_program *);
 475
 476 int     pcap_strcasecmp(const char *, const char *);
 477
 478 #ifdef __cplusplus
 479 }
 480 #endif
 481
 482 #endif