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 #include "portability.h"
50 #define PCAP_DEBUG {printf(" [%s:%d %s] ", __FILE__, __LINE__, __func__); fflush(stdout);}
53 * If we're compiling with Visual Studio, make sure we have at least
54 * VS 2015 or later, so we have sufficient C99 support.
56 * XXX - verify that we have at least C99 support on UN*Xes?
58 * What about MinGW or various DOS toolchains? We're currently assuming
59 * sufficient C99 support there.
63 * Compiler is MSVC. Make sure we have VS 2015 or later.
66 #error "Building libpcap requires VS 2015 or later"
72 * Uses PACKAGE_VERSION from config.h.
74 #define PCAP_VERSION_STRING "libpcap version " PACKAGE_VERSION
81 * If pcapint_new_api is set, we disable pcap_lookupdev(), because:
83 * it's not thread-safe, and is marked as deprecated, on all
86 * on Windows, it may return UTF-16LE strings, which the program
87 * might then pass to pcap_create() (or to pcap_open_live(), which
88 * then passes them to pcap_create()), requiring pcap_create() to
89 * check for UTF-16LE strings using a hack, and that hack 1)
90 * *cannot* be 100% reliable and 2) runs the risk of going past the
93 * We keep it around in legacy mode for compatibility.
95 * We also disable the aforementioned hack in pcap_create().
97 extern int pcapint_new_api
;
100 * If pcapint_utf_8_mode is set, on Windows we treat strings as UTF-8.
102 * On UN*Xes, we assume all strings are and should be in UTF-8, regardless
103 * of the setting of this flag.
105 extern int pcapint_utf_8_mode
;
108 * Map packet buffers with 32-bit addresses.
110 extern int pcapint_mmap_32bit
;
113 * Swap byte ordering of unsigned long long timestamp on a big endian
116 #define SWAPLL(ull) ((ull & 0xff00000000000000ULL) >> 56) | \
117 ((ull & 0x00ff000000000000ULL) >> 40) | \
118 ((ull & 0x0000ff0000000000ULL) >> 24) | \
119 ((ull & 0x000000ff00000000ULL) >> 8) | \
120 ((ull & 0x00000000ff000000ULL) << 8) | \
121 ((ull & 0x0000000000ff0000ULL) << 24) | \
122 ((ull & 0x000000000000ff00ULL) << 40) | \
123 ((ull & 0x00000000000000ffULL) << 56)
126 * Maximum snapshot length.
128 * Somewhat arbitrary, but chosen to be:
130 * 1) big enough for maximum-size Linux loopback packets (65549)
131 * and some USB packets captured with USBPcap:
133 * https://desowin.org/usbpcap/
135 * (> 131072, < 262144)
139 * 2) small enough not to cause attempts to allocate huge amounts of
140 * memory; some applications might use the snapshot length in a
141 * savefile header to control the size of the buffer they allocate,
142 * so a size of, say, 2^31-1 might not work well. (libpcap uses it
143 * as a hint, but doesn't start out allocating a buffer bigger than
144 * 2 KiB, and grows the buffer as necessary, but not beyond the
145 * per-linktype maximum snapshot length. Other code might naively
146 * use it; we want to avoid writing a too-large snapshot length,
147 * in order not to cause that code problems.)
149 * We don't enforce this in pcap_set_snaplen(), but we use it internally.
151 #define MAXIMUM_SNAPLEN 262144
154 * Locale-independent macros for testing character types.
155 * These can be passed any integral value, without worrying about, for
156 * example, sign-extending char values, unlike the C macros.
158 #define PCAP_ISDIGIT(c) \
159 ((c) >= '0' && (c) <= '9')
160 #define PCAP_ISXDIGIT(c) \
161 (((c) >= '0' && (c) <= '9') || \
162 ((c) >= 'A' && (c) <= 'F') || \
163 ((c) >= 'a' && (c) <= 'f'))
167 int timeout
; /* timeout for buffering */
170 int rfmon
; /* monitor mode */
171 int immediate
; /* immediate mode - deliver packets as soon as they arrive */
172 int nonblock
; /* non-blocking mode - don't wait for packets to be delivered, return "no packets available" */
174 int tstamp_precision
;
177 * Platform-dependent options.
180 int protocol
; /* protocol to use when creating PF_PACKET socket */
183 int nocapture_local
;/* disable NPF loopback */
187 typedef int (*activate_op_t
)(pcap_t
*);
188 typedef int (*can_set_rfmon_op_t
)(pcap_t
*);
189 typedef int (*read_op_t
)(pcap_t
*, int cnt
, pcap_handler
, u_char
*);
190 typedef int (*next_packet_op_t
)(pcap_t
*, struct pcap_pkthdr
*, u_char
**);
191 typedef int (*inject_op_t
)(pcap_t
*, const void *, int);
192 typedef void (*save_current_filter_op_t
)(pcap_t
*, const char *);
193 typedef int (*setfilter_op_t
)(pcap_t
*, struct bpf_program
*);
194 typedef int (*setdirection_op_t
)(pcap_t
*, pcap_direction_t
);
195 typedef int (*set_datalink_op_t
)(pcap_t
*, int);
196 typedef int (*getnonblock_op_t
)(pcap_t
*);
197 typedef int (*setnonblock_op_t
)(pcap_t
*, int);
198 typedef int (*stats_op_t
)(pcap_t
*, struct pcap_stat
*);
199 typedef void (*breakloop_op_t
)(pcap_t
*);
201 typedef struct pcap_stat
*(*stats_ex_op_t
)(pcap_t
*, int *);
202 typedef int (*setbuff_op_t
)(pcap_t
*, int);
203 typedef int (*setmode_op_t
)(pcap_t
*, int);
204 typedef int (*setmintocopy_op_t
)(pcap_t
*, int);
205 typedef HANDLE (*getevent_op_t
)(pcap_t
*);
206 typedef int (*oid_get_request_op_t
)(pcap_t
*, bpf_u_int32
, void *, size_t *);
207 typedef int (*oid_set_request_op_t
)(pcap_t
*, bpf_u_int32
, const void *, size_t *);
208 typedef u_int (*sendqueue_transmit_op_t
)(pcap_t
*, pcap_send_queue
*, int);
209 typedef int (*setuserbuffer_op_t
)(pcap_t
*, int);
210 typedef int (*live_dump_op_t
)(pcap_t
*, char *, int, int);
211 typedef int (*live_dump_ended_op_t
)(pcap_t
*, int);
212 typedef PAirpcapHandle (*get_airpcap_handle_op_t
)(pcap_t
*);
214 typedef void (*cleanup_op_t
)(pcap_t
*);
217 * We put all the stuff used in the read code path at the beginning,
218 * to try to keep it together in the same cache line or lines.
222 * Method to call to read packets on a live capture.
227 * Method to call to read the next packet from a savefile.
229 next_packet_op_t next_packet_op
;
245 sig_atomic_t break_loop
; /* flag set to force break from packet-reading loop */
247 void *priv
; /* private data for methods */
250 struct pcap_samp rmt_samp
; /* parameters related to the sampling process. */
254 FILE *rfile
; /* null if live capture, non-null if savefile */
256 struct pcap
*next
; /* list of open pcaps that need stuff cleared on close */
259 * File version number; meaningful only for a savefile, but we
260 * keep it here so that apps that (mistakenly) ask for the
261 * version numbers will get the same zero values that they
268 int linktype
; /* Network linktype */
269 int linktype_ext
; /* Extended information stored in the linktype field of a file */
270 int offset
; /* offset for proper alignment */
271 int activated
; /* true if the capture is really started */
272 int oldstyle
; /* if we're opening with pcap_open_live() */
277 * Place holder for pcap_next().
282 struct pcap_stat stat
; /* used for pcap_stats_ex() */
285 /* We're accepting only packets in this direction/these directions. */
286 pcap_direction_t direction
;
289 * Flags to affect BPF code generation.
291 int bpf_codegen_flags
;
294 int selectable_fd
; /* FD on which select()/poll()/epoll_wait()/kevent()/etc. can be done */
297 * In case there either is no selectable FD, or there is but
298 * it doesn't necessarily work (e.g., if it doesn't get notified
299 * if the packet capture timeout expires before the buffer
300 * fills up), this points to a timeout that should be used
301 * in select()/poll()/epoll_wait()/kevent() call. The pcap_t should
302 * be put into non-blocking mode, and, if the timeout expires on
303 * the call, an attempt should be made to read packets from all
304 * pcap_t's with a required timeout, and the code must be
305 * prepared not to see any packets from the attempt.
307 const struct timeval
*required_select_timeout
;
311 * Placeholder for filter code if bpf not in kernel.
313 struct bpf_program fcode
;
315 char errbuf
[PCAP_ERRBUF_SIZE
+ 1];
317 char acp_errbuf
[PCAP_ERRBUF_SIZE
+ 1]; /* buffer for local code page error strings */
321 int tstamp_type_count
;
322 u_int
*tstamp_type_list
;
323 int tstamp_precision_count
;
324 u_int
*tstamp_precision_list
;
326 struct pcap_pkthdr pcap_header
; /* This is needed for the pcap_next_ex() to work */
331 activate_op_t activate_op
;
332 can_set_rfmon_op_t can_set_rfmon_op
;
333 inject_op_t inject_op
;
334 save_current_filter_op_t save_current_filter_op
;
335 setfilter_op_t setfilter_op
;
336 setdirection_op_t setdirection_op
;
337 set_datalink_op_t set_datalink_op
;
338 getnonblock_op_t getnonblock_op
;
339 setnonblock_op_t setnonblock_op
;
341 breakloop_op_t breakloop_op
;
344 * Routine to use as callback for pcap_next()/pcap_next_ex().
346 pcap_handler oneshot_callback
;
350 * These are, at least currently, specific to the Win32 NPF
353 stats_ex_op_t stats_ex_op
;
354 setbuff_op_t setbuff_op
;
355 setmode_op_t setmode_op
;
356 setmintocopy_op_t setmintocopy_op
;
357 getevent_op_t getevent_op
;
358 oid_get_request_op_t oid_get_request_op
;
359 oid_set_request_op_t oid_set_request_op
;
360 sendqueue_transmit_op_t sendqueue_transmit_op
;
361 setuserbuffer_op_t setuserbuffer_op
;
362 live_dump_op_t live_dump_op
;
363 live_dump_ended_op_t live_dump_ended_op
;
364 get_airpcap_handle_op_t get_airpcap_handle_op
;
366 cleanup_op_t cleanup_op
;
370 * BPF code generation flags.
372 #define BPF_SPECIAL_VLAN_HANDLING 0x00000001 /* special VLAN handling for Linux */
375 * This is a timeval as stored in a savefile.
376 * It has to use the same types everywhere, independent of the actual
377 * `struct timeval'; `struct timeval' has 32-bit tv_sec values on some
378 * platforms and 64-bit tv_sec values on other platforms, and writing
379 * out native `struct timeval' values would mean files could only be
380 * read on systems with the same tv_sec size as the system on which
381 * the file was written.
384 struct pcap_timeval
{
385 bpf_int32 tv_sec
; /* seconds */
386 bpf_int32 tv_usec
; /* microseconds */
390 * This is a `pcap_pkthdr' as actually stored in a savefile.
392 * Do not change the format of this structure, in any way (this includes
393 * changes that only affect the length of fields in this structure),
394 * and do not make the time stamp anything other than seconds and
395 * microseconds (e.g., seconds and nanoseconds). Instead:
397 * introduce a new structure for the new format;
399 * send mail to "tcpdump-workers@lists.tcpdump.org", requesting
400 * a new magic number for your new capture file format, and, when
401 * you get the new magic number, put it in "savefile.c";
403 * use that magic number for save files with the changed record
406 * make the code in "savefile.c" capable of reading files with
407 * the old record header as well as files with the new record header
408 * (using the magic number to determine the header format).
410 * Then supply the changes by forking the branch at
412 * https://github.com/the-tcpdump-group/libpcap/tree/master
414 * and issuing a pull request, so that future versions of libpcap and
415 * programs that use it (such as tcpdump) will be able to read your new
416 * capture file format.
419 struct pcap_sf_pkthdr
{
420 struct pcap_timeval ts
; /* time stamp */
421 bpf_u_int32 caplen
; /* length of portion present */
422 bpf_u_int32 len
; /* length of this packet (off wire) */
426 * How a `pcap_pkthdr' is actually stored in savefiles written
427 * by some patched versions of libpcap (e.g. the ones in Red
428 * Hat Linux 6.1 and 6.2).
430 * Do not change the format of this structure, in any way (this includes
431 * changes that only affect the length of fields in this structure).
432 * Instead, introduce a new structure, as per the above.
435 struct pcap_sf_patched_pkthdr
{
436 struct pcap_timeval ts
; /* time stamp */
437 bpf_u_int32 caplen
; /* length of portion present */
438 bpf_u_int32 len
; /* length of this packet (off wire) */
440 unsigned short protocol
;
441 unsigned char pkt_type
;
445 * User data structure for the one-shot callback used for pcap_next()
446 * and pcap_next_ex().
448 struct oneshot_userdata
{
449 struct pcap_pkthdr
*hdr
;
455 #define min(a, b) ((a) > (b) ? (b) : (a))
458 int pcapint_offline_read(pcap_t
*, int, pcap_handler
, u_char
*);
461 * Does the packet count argument to a module's read routine say
462 * "supply packets until you run out of packets"?
464 #define PACKET_COUNT_IS_UNLIMITED(count) ((count) <= 0)
467 * Routines that most pcap implementations can use for non-blocking mode.
470 int pcapint_getnonblock_fd(pcap_t
*);
471 int pcapint_setnonblock_fd(pcap_t
*p
, int);
475 * Internal interfaces for "pcap_create()".
477 * "pcapint_create_interface()" is the routine to do a pcap_create on
478 * a regular network interface. There are multiple implementations
479 * of this, one for each platform type (Linux, BPF, DLPI, etc.),
480 * with the one used chosen by the configure script.
482 * "pcapint_create_common()" allocates and fills in a pcap_t, for use
483 * by pcap_create routines.
485 pcap_t
*pcapint_create_interface(const char *, char *);
488 * This wrapper takes an error buffer pointer and a type to use for the
489 * private data, and calls pcapint_create_common(), passing it the error
490 * buffer pointer, the size for the private data type, in bytes, and the
491 * offset of the private data from the beginning of the structure, in
494 #define PCAP_CREATE_COMMON(ebuf, type) \
495 pcapint_create_common(ebuf, \
496 sizeof (struct { pcap_t __common; type __private; }), \
497 offsetof (struct { pcap_t __common; type __private; }, __private))
498 pcap_t
*pcapint_create_common(char *, size_t, size_t);
499 int pcapint_do_addexit(pcap_t
*);
500 void pcapint_add_to_pcaps_to_close(pcap_t
*);
501 void pcapint_remove_from_pcaps_to_close(pcap_t
*);
502 void pcapint_cleanup_live_common(pcap_t
*);
503 int pcapint_check_activated(pcap_t
*);
504 void pcapint_breakloop_common(pcap_t
*);
507 * Internal interfaces for "pcap_findalldevs()".
509 * A pcap_if_list_t * is a reference to a list of devices.
511 * A get_if_flags_func is a platform-dependent function called to get
512 * additional interface flags.
514 * "pcapint_platform_finddevs()" is the platform-dependent routine to
515 * find local network interfaces.
517 * "pcapint_findalldevs_interfaces()" is a helper to find those interfaces
518 * using the "standard" mechanisms (SIOCGIFCONF, "getifaddrs()", etc.).
520 * "pcapint_add_dev()" adds an entry to a pcap_if_list_t.
522 * "pcap_add_any_dev()" adds an entry for the "any" device to a pcap_if_list_t.
524 * "pcapint_find_dev()" tries to find a device, by name, in a pcap_if_list_t.
526 * "pcapint_find_or_add_dev()" checks whether a device is already in a
527 * pcap_if_list_t and, if not, adds an entry for it.
530 typedef struct pcap_if_list pcap_if_list_t
;
531 typedef int (*get_if_flags_func
)(const char *, bpf_u_int32
*, char *);
532 int pcapint_platform_finddevs(pcap_if_list_t
*, char *);
534 int pcapint_findalldevs_interfaces(pcap_if_list_t
*, char *,
535 int (*)(const char *), get_if_flags_func
);
537 pcap_if_t
*pcapint_find_or_add_dev(pcap_if_list_t
*, const char *, bpf_u_int32
,
538 get_if_flags_func
, const char *, char *);
539 pcap_if_t
*pcapint_find_dev(pcap_if_list_t
*, const char *);
540 pcap_if_t
*pcapint_add_dev(pcap_if_list_t
*, const char *, bpf_u_int32
,
541 const char *, char *);
542 pcap_if_t
*pcap_add_any_dev(pcap_if_list_t
*, char *);
543 int pcapint_add_addr_to_dev(pcap_if_t
*, struct sockaddr
*, size_t,
544 struct sockaddr
*, size_t, struct sockaddr
*, size_t,
545 struct sockaddr
*dstaddr
, size_t, char *errbuf
);
547 pcap_if_t
*pcapint_find_or_add_if(pcap_if_list_t
*, const char *, bpf_u_int32
,
548 get_if_flags_func
, char *);
549 int pcapint_add_addr_to_if(pcap_if_list_t
*, const char *, bpf_u_int32
,
551 struct sockaddr
*, size_t, struct sockaddr
*, size_t,
552 struct sockaddr
*, size_t, struct sockaddr
*, size_t, char *);
556 * Internal interfaces for "pcap_open_offline()" and other savefile
559 * "pcapint_open_offline_common()" allocates and fills in a pcap_t, for use
560 * by pcap_open_offline routines.
562 * "pcapint_adjust_snapshot()" adjusts the snapshot to be non-zero and
565 * "pcapint_sf_cleanup()" closes the file handle associated with a pcap_t, if
566 * appropriate, and frees all data common to all modules for handling
569 * "pcapint_charset_fopen()", in UTF-8 mode on Windows, does an fopen() that
570 * treats the pathname as being in UTF-8, rather than the local
571 * code page, on Windows.
575 * This wrapper takes an error buffer pointer and a type to use for the
576 * private data, and calls pcapint_create_common(), passing it the error
577 * buffer pointer, the size for the private data type, in bytes, and the
578 * offset of the private data from the beginning of the structure, in
581 #define PCAP_OPEN_OFFLINE_COMMON(ebuf, type) \
582 pcapint_open_offline_common(ebuf, \
583 sizeof (struct { pcap_t __common; type __private; }), \
584 offsetof (struct { pcap_t __common; type __private; }, __private))
585 pcap_t
*pcapint_open_offline_common(char *ebuf
, size_t total_size
,
586 size_t private_data
);
587 bpf_u_int32
pcapint_adjust_snapshot(bpf_u_int32 linktype
, bpf_u_int32 snaplen
);
588 void pcapint_sf_cleanup(pcap_t
*p
);
590 FILE *pcapint_charset_fopen(const char *path
, const char *mode
);
593 * On other OSes, just use Boring Old fopen().
595 #define pcapint_charset_fopen(path, mode) fopen((path), (mode))
599 * Internal interfaces for loading code at run time.
602 #define pcap_code_handle_t HMODULE
603 #define pcap_funcptr_t FARPROC
605 pcap_code_handle_t
pcapint_load_code(const char *);
606 pcap_funcptr_t
pcapint_find_function(pcap_code_handle_t
, const char *);
610 * Internal interfaces for doing user-mode filtering of packets and
611 * validating filter programs.
614 * Auxiliary data, for use when interpreting a filter intended for the
615 * Linux kernel when the kernel rejects the filter (requiring us to
616 * run it in userland). It contains VLAN tag information.
618 struct pcap_bpf_aux_data
{
619 u_short vlan_tag_present
;
624 * Filtering routine that takes the auxiliary data as an additional
627 u_int
pcapint_filter_with_aux_data(const struct bpf_insn
*,
628 const u_char
*, u_int
, u_int
, const struct pcap_bpf_aux_data
*);
631 * Filtering routine that doesn't.
633 u_int
pcapint_filter(const struct bpf_insn
*, const u_char
*, u_int
, u_int
);
636 * Routine to validate a BPF program.
638 int pcapint_validate_filter(const struct bpf_insn
*, int);
641 * Internal interfaces for both "pcap_create()" and routines that
644 * "pcapint_oneshot()" is the standard one-shot callback for "pcap_next()"
645 * and "pcap_next_ex()".
647 void pcapint_oneshot(u_char
*, const struct pcap_pkthdr
*, const u_char
*);
649 int pcapint_install_bpf_program(pcap_t
*, struct bpf_program
*);
651 int pcapint_strcasecmp(const char *, const char *);
654 * Internal interfaces for pcap_createsrcstr and pcap_parsesrcstr with
655 * the additional bit of information regarding SSL support (rpcap:// vs.
658 int pcapint_createsrcstr_ex(char *, int, const char *, const char *,
659 const char *, const char *, unsigned char, char *);
660 int pcapint_parsesrcstr_ex(const char *, int *, char *, char *,
661 char *, char *, unsigned char *, char *);
664 extern int pcap_debug
;