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