2 * Copyright (c) 1994, 1995, 1996
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
41 #include <pcap/pcap.h>
48 * Uses PACKAGE_VERSION from config.h.
50 #define PCAP_VERSION_STRING "libpcap version " PACKAGE_VERSION
53 * If pcap_new_api is set, we disable pcap_lookupdev(), because:
55 * it's not thread-safe, and is marked as deprecated, on all
58 * on Windows, it may return UTF-16LE strings, which the program
59 * might then pass to pcap_create() (or to pcap_open_live(), which
60 * then passes them to pcap_create()), requiring pcap_create() to
61 * check for UTF-16LE strings using a hack, and that hack 1)
62 * *cannot* be 100% reliable and 2) runs the risk of going past the
65 * We keep it around in legacy mode for compatibility.
67 * We also disable the aforementioned hack in pcap_create().
69 extern int pcap_new_api
;
72 * If pcap_utf_8_mode is set, on Windows we treat strings as UTF-8.
74 * On UN*Xes, we assume all strings are and should be in UTF-8, regardless
75 * of the setting of this flag.
77 extern int pcap_utf_8_mode
;
85 * Swap byte ordering of unsigned long long timestamp on a big endian
88 #define SWAPLL(ull) ((ull & 0xff00000000000000ULL) >> 56) | \
89 ((ull & 0x00ff000000000000ULL) >> 40) | \
90 ((ull & 0x0000ff0000000000ULL) >> 24) | \
91 ((ull & 0x000000ff00000000ULL) >> 8) | \
92 ((ull & 0x00000000ff000000ULL) << 8) | \
93 ((ull & 0x0000000000ff0000ULL) << 24) | \
94 ((ull & 0x000000000000ff00ULL) << 40) | \
95 ((ull & 0x00000000000000ffULL) << 56)
98 * Maximum snapshot length.
100 * Somewhat arbitrary, but chosen to be:
102 * 1) big enough for maximum-size Linux loopback packets (65549)
103 * and some USB packets captured with USBPcap:
105 * https://desowin.org/usbpcap/
107 * (> 131072, < 262144)
111 * 2) small enough not to cause attempts to allocate huge amounts of
112 * memory; some applications might use the snapshot length in a
113 * savefile header to control the size of the buffer they allocate,
114 * so a size of, say, 2^31-1 might not work well. (libpcap uses it
115 * as a hint, but doesn't start out allocating a buffer bigger than
116 * 2 KiB, and grows the buffer as necessary, but not beyond the
117 * per-linktype maximum snapshot length. Other code might naively
118 * use it; we want to avoid writing a too-large snapshot length,
119 * in order not to cause that code problems.)
121 * We don't enforce this in pcap_set_snaplen(), but we use it internally.
123 #define MAXIMUM_SNAPLEN 262144
126 * Locale-independent macros for testing character types.
127 * These can be passed any integral value, without worrying about, for
128 * example, sign-extending char values, unlike the C macros.
130 #define PCAP_ISDIGIT(c) \
131 ((c) >= '0' && (c) <= '9')
132 #define PCAP_ISXDIGIT(c) \
133 (((c) >= '0' && (c) <= '9') || \
134 ((c) >= 'A' && (c) <= 'F') || \
135 ((c) >= 'a' && (c) <= 'f'))
139 int timeout
; /* timeout for buffering */
142 int rfmon
; /* monitor mode */
143 int immediate
; /* immediate mode - deliver packets as soon as they arrive */
144 int nonblock
; /* non-blocking mode - don't wait for packets to be delivered, return "no packets available" */
146 int tstamp_precision
;
149 * Platform-dependent options.
152 int protocol
; /* protocol to use when creating PF_PACKET socket */
155 int nocapture_local
;/* disable NPF loopback */
159 typedef int (*activate_op_t
)(pcap_t
*);
160 typedef int (*can_set_rfmon_op_t
)(pcap_t
*);
161 typedef int (*read_op_t
)(pcap_t
*, int cnt
, pcap_handler
, u_char
*);
162 typedef int (*next_packet_op_t
)(pcap_t
*, struct pcap_pkthdr
*, u_char
**);
163 typedef int (*inject_op_t
)(pcap_t
*, const void *, int);
164 typedef void (*save_current_filter_op_t
)(pcap_t
*, const char *);
165 typedef int (*setfilter_op_t
)(pcap_t
*, struct bpf_program
*);
166 typedef int (*setdirection_op_t
)(pcap_t
*, pcap_direction_t
);
167 typedef int (*set_datalink_op_t
)(pcap_t
*, int);
168 typedef int (*getnonblock_op_t
)(pcap_t
*);
169 typedef int (*setnonblock_op_t
)(pcap_t
*, int);
170 typedef int (*stats_op_t
)(pcap_t
*, struct pcap_stat
*);
171 typedef void (*breakloop_op_t
)(pcap_t
*);
173 typedef struct pcap_stat
*(*stats_ex_op_t
)(pcap_t
*, int *);
174 typedef int (*setbuff_op_t
)(pcap_t
*, int);
175 typedef int (*setmode_op_t
)(pcap_t
*, int);
176 typedef int (*setmintocopy_op_t
)(pcap_t
*, int);
177 typedef HANDLE (*getevent_op_t
)(pcap_t
*);
178 typedef int (*oid_get_request_op_t
)(pcap_t
*, bpf_u_int32
, void *, size_t *);
179 typedef int (*oid_set_request_op_t
)(pcap_t
*, bpf_u_int32
, const void *, size_t *);
180 typedef u_int (*sendqueue_transmit_op_t
)(pcap_t
*, pcap_send_queue
*, int);
181 typedef int (*setuserbuffer_op_t
)(pcap_t
*, int);
182 typedef int (*live_dump_op_t
)(pcap_t
*, char *, int, int);
183 typedef int (*live_dump_ended_op_t
)(pcap_t
*, int);
184 typedef PAirpcapHandle (*get_airpcap_handle_op_t
)(pcap_t
*);
186 typedef void (*cleanup_op_t
)(pcap_t
*);
189 * We put all the stuff used in the read code path at the beginning,
190 * to try to keep it together in the same cache line or lines.
194 * Method to call to read packets on a live capture.
199 * Method to call to read the next packet from a savefile.
201 next_packet_op_t next_packet_op
;
217 sig_atomic_t break_loop
; /* flag set to force break from packet-reading loop */
219 void *priv
; /* private data for methods */
222 struct pcap_samp rmt_samp
; /* parameters related to the sampling process. */
226 FILE *rfile
; /* null if live capture, non-null if savefile */
228 struct pcap
*next
; /* list of open pcaps that need stuff cleared on close */
231 * File version number; meaningful only for a savefile, but we
232 * keep it here so that apps that (mistakenly) ask for the
233 * version numbers will get the same zero values that they
240 int linktype
; /* Network linktype */
241 int linktype_ext
; /* Extended information stored in the linktype field of a file */
242 int offset
; /* offset for proper alignment */
243 int activated
; /* true if the capture is really started */
244 int oldstyle
; /* if we're opening with pcap_open_live() */
249 * Place holder for pcap_next().
254 struct pcap_stat stat
; /* used for pcap_stats_ex() */
257 /* We're accepting only packets in this direction/these directions. */
258 pcap_direction_t direction
;
261 * Flags to affect BPF code generation.
263 int bpf_codegen_flags
;
265 #if !defined(_WIN32) && !defined(MSDOS)
266 int selectable_fd
; /* FD on which select()/poll()/epoll_wait()/kevent()/etc. can be done */
269 * In case there either is no selectable FD, or there is but
270 * it doesn't necessarily work (e.g., if it doesn't get notified
271 * if the packet capture timeout expires before the buffer
272 * fills up), this points to a timeout that should be used
273 * in select()/poll()/epoll_wait()/kevent() call. The pcap_t should
274 * be put into non-blocking mode, and, if the timeout expires on
275 * the call, an attempt should be made to read packets from all
276 * pcap_t's with a required timeout, and the code must be
277 * prepared not to see any packets from the attempt.
279 const struct timeval
*required_select_timeout
;
283 * Placeholder for filter code if bpf not in kernel.
285 struct bpf_program fcode
;
287 char errbuf
[PCAP_ERRBUF_SIZE
+ 1];
289 char acp_errbuf
[PCAP_ERRBUF_SIZE
+ 1]; /* buffer for local code page error strings */
293 int tstamp_type_count
;
294 u_int
*tstamp_type_list
;
295 int tstamp_precision_count
;
296 u_int
*tstamp_precision_list
;
298 struct pcap_pkthdr pcap_header
; /* This is needed for the pcap_next_ex() to work */
303 activate_op_t activate_op
;
304 can_set_rfmon_op_t can_set_rfmon_op
;
305 inject_op_t inject_op
;
306 save_current_filter_op_t save_current_filter_op
;
307 setfilter_op_t setfilter_op
;
308 setdirection_op_t setdirection_op
;
309 set_datalink_op_t set_datalink_op
;
310 getnonblock_op_t getnonblock_op
;
311 setnonblock_op_t setnonblock_op
;
313 breakloop_op_t breakloop_op
;
316 * Routine to use as callback for pcap_next()/pcap_next_ex().
318 pcap_handler oneshot_callback
;
322 * These are, at least currently, specific to the Win32 NPF
325 stats_ex_op_t stats_ex_op
;
326 setbuff_op_t setbuff_op
;
327 setmode_op_t setmode_op
;
328 setmintocopy_op_t setmintocopy_op
;
329 getevent_op_t getevent_op
;
330 oid_get_request_op_t oid_get_request_op
;
331 oid_set_request_op_t oid_set_request_op
;
332 sendqueue_transmit_op_t sendqueue_transmit_op
;
333 setuserbuffer_op_t setuserbuffer_op
;
334 live_dump_op_t live_dump_op
;
335 live_dump_ended_op_t live_dump_ended_op
;
336 get_airpcap_handle_op_t get_airpcap_handle_op
;
338 cleanup_op_t cleanup_op
;
342 * BPF code generation flags.
344 #define BPF_SPECIAL_VLAN_HANDLING 0x00000001 /* special VLAN handling for Linux */
347 * This is a timeval as stored in a savefile.
348 * It has to use the same types everywhere, independent of the actual
349 * `struct timeval'; `struct timeval' has 32-bit tv_sec values on some
350 * platforms and 64-bit tv_sec values on other platforms, and writing
351 * out native `struct timeval' values would mean files could only be
352 * read on systems with the same tv_sec size as the system on which
353 * the file was written.
356 struct pcap_timeval
{
357 bpf_int32 tv_sec
; /* seconds */
358 bpf_int32 tv_usec
; /* microseconds */
362 * This is a `pcap_pkthdr' as actually stored in a savefile.
364 * Do not change the format of this structure, in any way (this includes
365 * changes that only affect the length of fields in this structure),
366 * and do not make the time stamp anything other than seconds and
367 * microseconds (e.g., seconds and nanoseconds). Instead:
369 * introduce a new structure for the new format;
371 * send mail to "tcpdump-workers@lists.tcpdump.org", requesting
372 * a new magic number for your new capture file format, and, when
373 * you get the new magic number, put it in "savefile.c";
375 * use that magic number for save files with the changed record
378 * make the code in "savefile.c" capable of reading files with
379 * the old record header as well as files with the new record header
380 * (using the magic number to determine the header format).
382 * Then supply the changes by forking the branch at
384 * https://github.com/the-tcpdump-group/libpcap/tree/master
386 * and issuing a pull request, so that future versions of libpcap and
387 * programs that use it (such as tcpdump) will be able to read your new
388 * capture file format.
391 struct pcap_sf_pkthdr
{
392 struct pcap_timeval ts
; /* time stamp */
393 bpf_u_int32 caplen
; /* length of portion present */
394 bpf_u_int32 len
; /* length of this packet (off wire) */
398 * How a `pcap_pkthdr' is actually stored in savefiles written
399 * by some patched versions of libpcap (e.g. the ones in Red
400 * Hat Linux 6.1 and 6.2).
402 * Do not change the format of this structure, in any way (this includes
403 * changes that only affect the length of fields in this structure).
404 * Instead, introduce a new structure, as per the above.
407 struct pcap_sf_patched_pkthdr
{
408 struct pcap_timeval ts
; /* time stamp */
409 bpf_u_int32 caplen
; /* length of portion present */
410 bpf_u_int32 len
; /* length of this packet (off wire) */
412 unsigned short protocol
;
413 unsigned char pkt_type
;
417 * User data structure for the one-shot callback used for pcap_next()
418 * and pcap_next_ex().
420 struct oneshot_userdata
{
421 struct pcap_pkthdr
*hdr
;
427 #define min(a, b) ((a) > (b) ? (b) : (a))
430 PCAP_UNEXPORTED_C_FUNC
int pcap_offline_read(pcap_t
*, int, pcap_handler
, u_char
*);
434 #include "portability.h"
437 * Does the packet count argument to a module's read routine say
438 * "supply packets until you run out of packets"?
440 #define PACKET_COUNT_IS_UNLIMITED(count) ((count) <= 0)
443 * Routines that most pcap implementations can use for non-blocking mode.
445 #if !defined(_WIN32) && !defined(MSDOS)
446 PCAP_UNEXPORTED_C_FUNC
int pcap_getnonblock_fd(pcap_t
*);
447 PCAP_UNEXPORTED_C_FUNC
int pcap_setnonblock_fd(pcap_t
*p
, int);
451 * Internal interfaces for "pcap_create()".
453 * "pcap_create_interface()" is the routine to do a pcap_create on
454 * a regular network interface. There are multiple implementations
455 * of this, one for each platform type (Linux, BPF, DLPI, etc.),
456 * with the one used chosen by the configure script.
458 * "pcap_create_common()" allocates and fills in a pcap_t, for use
459 * by pcap_create routines.
461 PCAP_UNEXPORTED_C_FUNC pcap_t
*pcap_create_interface(const char *, char *);
464 * This wrapper takes an error buffer pointer and a type to use for the
465 * private data, and calls pcap_create_common(), passing it the error
466 * buffer pointer, the size fo the private data type, in bytes, and the
467 * offset of the private data from the beginning of the structure, in
470 #define PCAP_CREATE_COMMON(ebuf, type) \
471 pcap_create_common(ebuf, \
472 sizeof (struct { pcap_t __common; type __private; }), \
473 offsetof (struct { pcap_t __common; type __private; }, __private))
474 PCAP_UNEXPORTED_C_FUNC pcap_t
*pcap_create_common(char *, size_t, size_t);
475 PCAP_UNEXPORTED_C_FUNC
int pcap_do_addexit(pcap_t
*);
476 PCAP_UNEXPORTED_C_FUNC
void pcap_add_to_pcaps_to_close(pcap_t
*);
477 PCAP_UNEXPORTED_C_FUNC
void pcap_remove_from_pcaps_to_close(pcap_t
*);
478 PCAP_UNEXPORTED_C_FUNC
void pcap_cleanup_live_common(pcap_t
*);
479 PCAP_UNEXPORTED_C_FUNC
int pcap_check_activated(pcap_t
*);
480 PCAP_UNEXPORTED_C_FUNC
void pcap_breakloop_common(pcap_t
*);
483 * Internal interfaces for "pcap_findalldevs()".
485 * A pcap_if_list_t * is a reference to a list of devices.
487 * A get_if_flags_func is a platform-dependent function called to get
488 * additional interface flags.
490 * "pcap_platform_finddevs()" is the platform-dependent routine to
491 * find local network interfaces.
493 * "pcap_findalldevs_interfaces()" is a helper to find those interfaces
494 * using the "standard" mechanisms (SIOCGIFCONF, "getifaddrs()", etc.).
496 * "add_dev()" adds an entry to a pcap_if_list_t.
498 * "find_dev()" tries to find a device, by name, in a pcap_if_list_t.
500 * "find_or_add_dev()" checks whether a device is already in a pcap_if_list_t
501 * and, if not, adds an entry for it.
504 typedef struct pcap_if_list pcap_if_list_t
;
505 typedef int (*get_if_flags_func
)(const char *, bpf_u_int32
*, char *);
506 PCAP_UNEXPORTED_C_FUNC
int pcap_platform_finddevs(pcap_if_list_t
*, char *);
507 #if !defined(_WIN32) && !defined(MSDOS)
508 PCAP_UNEXPORTED_C_FUNC
int pcap_findalldevs_interfaces(pcap_if_list_t
*, char *,
509 int (*)(const char *), get_if_flags_func
);
511 PCAP_UNEXPORTED_C_FUNC pcap_if_t
*find_or_add_dev(pcap_if_list_t
*, const char *,
512 bpf_u_int32
, get_if_flags_func
, const char *, char *);
513 PCAP_UNEXPORTED_C_FUNC pcap_if_t
*find_dev(pcap_if_list_t
*, const char *);
514 PCAP_UNEXPORTED_C_FUNC pcap_if_t
*add_dev(pcap_if_list_t
*, const char *, bpf_u_int32
,
515 const char *, char *);
516 PCAP_UNEXPORTED_C_FUNC
int add_addr_to_dev(pcap_if_t
*, struct sockaddr
*, size_t,
517 struct sockaddr
*, size_t, struct sockaddr
*, size_t,
518 struct sockaddr
*dstaddr
, size_t, char *errbuf
);
520 PCAP_UNEXPORTED_C_FUNC pcap_if_t
*find_or_add_if(pcap_if_list_t
*, const char *,
521 bpf_u_int32
, get_if_flags_func
, char *);
522 PCAP_UNEXPORTED_C_FUNC
int add_addr_to_if(pcap_if_list_t
*, const char *, bpf_u_int32
,
524 struct sockaddr
*, size_t, struct sockaddr
*, size_t,
525 struct sockaddr
*, size_t, struct sockaddr
*, size_t, char *);
529 * Internal interfaces for "pcap_open_offline()" and other savefile
532 * "pcap_open_offline_common()" allocates and fills in a pcap_t, for use
533 * by pcap_open_offline routines.
535 * "pcap_adjust_snapshot()" adjusts the snapshot to be non-zero and
538 * "sf_cleanup()" closes the file handle associated with a pcap_t, if
539 * appropriate, and frees all data common to all modules for handling
542 * "charset_fopen()", in UTF-8 mode on Windows, does an fopen() that
543 * treats the pathname as being in UTF-8, rather than the local
544 * code page, on Windows.
548 * This wrapper takes an error buffer pointer and a type to use for the
549 * private data, and calls pcap_create_common(), passing it the error
550 * buffer pointer, the size fo the private data type, in bytes, and the
551 * offset of the private data from the beginning of the structure, in
554 #define PCAP_OPEN_OFFLINE_COMMON(ebuf, type) \
555 pcap_open_offline_common(ebuf, \
556 sizeof (struct { pcap_t __common; type __private; }), \
557 offsetof (struct { pcap_t __common; type __private; }, __private))
558 PCAP_UNEXPORTED_C_FUNC pcap_t
*pcap_open_offline_common(char *ebuf
, size_t total_size
,
559 size_t private_data
);
560 PCAP_UNEXPORTED_C_FUNC bpf_u_int32
pcap_adjust_snapshot(bpf_u_int32 linktype
,
561 bpf_u_int32 snaplen
);
562 PCAP_UNEXPORTED_C_FUNC
void sf_cleanup(pcap_t
*p
);
564 PCAP_UNEXPORTED_C_FUNC
FILE *charset_fopen(const char *path
, const char *mode
);
567 * On other OSes, just use Boring Old fopen().
569 #define charset_fopen(path, mode) fopen((path), (mode))
573 * Internal interfaces for loading code at run time.
576 #define pcap_code_handle_t HMODULE
577 #define pcap_funcptr_t FARPROC
579 PCAP_UNEXPORTED_C_FUNC pcap_code_handle_t
pcap_load_code(const char *);
580 PCAP_UNEXPORTED_C_FUNC pcap_funcptr_t
pcap_find_function(pcap_code_handle_t
,
585 * Internal interfaces for doing user-mode filtering of packets and
586 * validating filter programs.
589 * Auxiliary data, for use when interpreting a filter intended for the
590 * Linux kernel when the kernel rejects the filter (requiring us to
591 * run it in userland). It contains VLAN tag information.
593 struct pcap_bpf_aux_data
{
594 u_short vlan_tag_present
;
599 * Filtering routine that takes the auxiliary data as an additional
602 PCAP_UNEXPORTED_C_FUNC u_int
pcap_filter_with_aux_data(const struct bpf_insn
*,
603 const u_char
*, u_int
, u_int
, const struct pcap_bpf_aux_data
*);
606 * Filtering routine that doesn't.
608 PCAP_UNEXPORTED_C_FUNC u_int
pcap_filter(const struct bpf_insn
*, const u_char
*,
612 * Routine to validate a BPF program.
614 PCAP_UNEXPORTED_C_FUNC
int pcap_validate_filter(const struct bpf_insn
*, int);
617 * Internal interfaces for both "pcap_create()" and routines that
620 * "pcap_oneshot()" is the standard one-shot callback for "pcap_next()"
621 * and "pcap_next_ex()".
623 PCAP_UNEXPORTED_C_FUNC
void pcap_oneshot(u_char
*, const struct pcap_pkthdr
*,
626 PCAP_UNEXPORTED_C_FUNC
int install_bpf_program(pcap_t
*, struct bpf_program
*);
628 PCAP_UNEXPORTED_C_FUNC
int pcap_strcasecmp(const char *, const char *);
631 * Internal interfaces for pcap_createsrcstr and pcap_parsesrcstr with
632 * the additional bit of information regarding SSL support (rpcap:// vs.
635 PCAP_UNEXPORTED_C_FUNC
int pcap_createsrcstr_ex(char *, int, const char *, const char *,
636 const char *, unsigned char, char *);
637 PCAP_UNEXPORTED_C_FUNC
int pcap_parsesrcstr_ex(const char *, int *, char *, char *,
638 char *, unsigned char *, char *);
641 extern int pcap_debug
;