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