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? 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 * Maximum snapshot length.
115 * Somewhat arbitrary, but chosen to be:
117 * 1) big enough for maximum-size Linux loopback packets (65549)
118 * and some USB packets captured with USBPcap:
120 * https://desowin.org/usbpcap/
122 * (> 131072, < 262144)
126 * 2) small enough not to cause attempts to allocate huge amounts of
127 * memory; some applications might use the snapshot length in a
128 * savefile header to control the size of the buffer they allocate,
129 * so a size of, say, 2^31-1 might not work well. (libpcap uses it
130 * as a hint, but doesn't start out allocating a buffer bigger than
131 * 2 KiB, and grows the buffer as necessary, but not beyond the
132 * per-linktype maximum snapshot length. Other code might naively
133 * use it; we want to avoid writing a too-large snapshot length,
134 * in order not to cause that code problems.)
136 * We don't enforce this in pcap_set_snaplen(), but we use it internally.
138 #define MAXIMUM_SNAPLEN 262144
141 * Locale-independent macros for testing character types.
142 * These can be passed any integral value, without worrying about, for
143 * example, sign-extending char values, unlike the C macros.
145 #define PCAP_ISDIGIT(c) \
146 ((c) >= '0' && (c) <= '9')
147 #define PCAP_ISXDIGIT(c) \
148 (((c) >= '0' && (c) <= '9') || \
149 ((c) >= 'A' && (c) <= 'F') || \
150 ((c) >= 'a' && (c) <= 'f'))
154 int timeout
; /* timeout for buffering */
157 int rfmon
; /* monitor mode */
158 int immediate
; /* immediate mode - deliver packets as soon as they arrive */
159 int nonblock
; /* non-blocking mode - don't wait for packets to be delivered, return "no packets available" */
161 int tstamp_precision
;
164 * Platform-dependent options.
167 int protocol
; /* protocol to use when creating PF_PACKET socket */
170 int nocapture_local
;/* disable NPF loopback */
174 typedef int (*activate_op_t
)(pcap_t
*);
175 typedef int (*can_set_rfmon_op_t
)(pcap_t
*);
176 typedef int (*read_op_t
)(pcap_t
*, int cnt
, pcap_handler
, u_char
*);
177 typedef int (*next_packet_op_t
)(pcap_t
*, struct pcap_pkthdr
*, u_char
**);
178 typedef int (*inject_op_t
)(pcap_t
*, const void *, int);
179 typedef void (*save_current_filter_op_t
)(pcap_t
*, const char *);
180 typedef int (*setfilter_op_t
)(pcap_t
*, struct bpf_program
*);
181 typedef int (*setdirection_op_t
)(pcap_t
*, pcap_direction_t
);
182 typedef int (*set_datalink_op_t
)(pcap_t
*, int);
183 typedef int (*getnonblock_op_t
)(pcap_t
*);
184 typedef int (*setnonblock_op_t
)(pcap_t
*, int);
185 typedef int (*stats_op_t
)(pcap_t
*, struct pcap_stat
*);
186 typedef void (*breakloop_op_t
)(pcap_t
*);
188 typedef struct pcap_stat
*(*stats_ex_op_t
)(pcap_t
*, int *);
189 typedef int (*setbuff_op_t
)(pcap_t
*, int);
190 typedef int (*setmode_op_t
)(pcap_t
*, int);
191 typedef int (*setmintocopy_op_t
)(pcap_t
*, int);
192 typedef HANDLE (*getevent_op_t
)(pcap_t
*);
193 typedef int (*oid_get_request_op_t
)(pcap_t
*, bpf_u_int32
, void *, size_t *);
194 typedef int (*oid_set_request_op_t
)(pcap_t
*, bpf_u_int32
, const void *, size_t *);
195 typedef u_int (*sendqueue_transmit_op_t
)(pcap_t
*, pcap_send_queue
*, int);
196 typedef int (*setuserbuffer_op_t
)(pcap_t
*, int);
197 typedef int (*live_dump_op_t
)(pcap_t
*, char *, int, int);
198 typedef int (*live_dump_ended_op_t
)(pcap_t
*, int);
200 typedef void (*cleanup_op_t
)(pcap_t
*);
203 * We put all the stuff used in the read code path at the beginning,
204 * to try to keep it together in the same cache line or lines.
208 * Method to call to read packets on a live capture.
213 * Method to call to read the next packet from a savefile.
215 next_packet_op_t next_packet_op
;
231 sig_atomic_t break_loop
; /* flag set to force break from packet-reading loop */
233 void *priv
; /* private data for methods */
236 struct pcap_samp rmt_samp
; /* parameters related to the sampling process. */
240 FILE *rfile
; /* null if live capture, non-null if savefile */
242 struct pcap
*next
; /* list of open pcaps that need stuff cleared on close */
245 * File version number; meaningful only for a savefile, but we
246 * keep it here so that apps that (mistakenly) ask for the
247 * version numbers will get the same zero values that they
254 int linktype
; /* Network linktype */
255 int linktype_ext
; /* Extended information stored in the linktype field of a file */
256 u_int offset
; /* offset for proper alignment */
257 int activated
; /* true if the capture is really started */
258 int oldstyle
; /* if we're opening with pcap_open_live() */
263 * Place holder for pcap_next().
268 struct pcap_stat stat
; /* used for pcap_stats_ex() */
271 /* We're accepting only packets in this direction/these directions. */
272 pcap_direction_t direction
;
275 * Flags to affect BPF code generation.
277 int bpf_codegen_flags
;
280 int selectable_fd
; /* FD on which select()/poll()/epoll_wait()/kevent()/etc. can be done */
283 * In case there either is no selectable FD, or there is but
284 * it doesn't necessarily work (e.g., if it doesn't get notified
285 * if the packet capture timeout expires before the buffer
286 * fills up), this points to a timeout that should be used
287 * in select()/poll()/epoll_wait()/kevent() call. The pcap_t should
288 * be put into non-blocking mode, and, if the timeout expires on
289 * the call, an attempt should be made to read packets from all
290 * pcap_t's with a required timeout, and the code must be
291 * prepared not to see any packets from the attempt.
293 const struct timeval
*required_select_timeout
;
297 * Placeholder for filter code if bpf not in kernel.
299 struct bpf_program fcode
;
301 char errbuf
[PCAP_ERRBUF_SIZE
+ 1];
303 char acp_errbuf
[PCAP_ERRBUF_SIZE
+ 1]; /* buffer for local code page error strings */
307 int tstamp_type_count
;
308 u_int
*tstamp_type_list
;
309 int tstamp_precision_count
;
310 u_int
*tstamp_precision_list
;
312 struct pcap_pkthdr pcap_header
; /* This is needed for the pcap_next_ex() to work */
317 activate_op_t activate_op
;
318 can_set_rfmon_op_t can_set_rfmon_op
;
319 inject_op_t inject_op
;
320 save_current_filter_op_t save_current_filter_op
;
321 setfilter_op_t setfilter_op
;
322 setdirection_op_t setdirection_op
;
323 set_datalink_op_t set_datalink_op
;
324 getnonblock_op_t getnonblock_op
;
325 setnonblock_op_t setnonblock_op
;
327 breakloop_op_t breakloop_op
;
330 * Routine to use as callback for pcap_next()/pcap_next_ex().
332 pcap_handler oneshot_callback
;
336 * These are, at least currently, specific to the Win32 NPF
339 stats_ex_op_t stats_ex_op
;
340 setbuff_op_t setbuff_op
;
341 setmode_op_t setmode_op
;
342 setmintocopy_op_t setmintocopy_op
;
343 getevent_op_t getevent_op
;
344 oid_get_request_op_t oid_get_request_op
;
345 oid_set_request_op_t oid_set_request_op
;
346 sendqueue_transmit_op_t sendqueue_transmit_op
;
347 setuserbuffer_op_t setuserbuffer_op
;
348 live_dump_op_t live_dump_op
;
349 live_dump_ended_op_t live_dump_ended_op
;
351 cleanup_op_t cleanup_op
;
355 * BPF code generation flags.
357 #define BPF_SPECIAL_VLAN_HANDLING 0x00000001 /* special VLAN handling for Linux */
359 * Special handling of packet type and ifindex, which are some of the auxiliary
360 * data items available in Linux >= 2.6.27. Disregard protocol and netlink
361 * attributes for now.
363 #define BPF_SPECIAL_BASIC_HANDLING 0x00000002
366 * User data structure for the one-shot callback used for pcap_next()
367 * and pcap_next_ex().
369 struct oneshot_userdata
{
370 struct pcap_pkthdr
*hdr
;
376 #define min(a, b) ((a) > (b) ? (b) : (a))
379 #define max(a, b) ((a) > (b) ? (a) : (b))
382 int pcapint_offline_read(pcap_t
*, int, pcap_handler
, u_char
*);
385 * Does the packet count argument to a module's read routine say
386 * "supply packets until you run out of packets"?
388 #define PACKET_COUNT_IS_UNLIMITED(count) ((count) <= 0)
391 * Routines that most pcap implementations can use for non-blocking mode.
394 int pcapint_getnonblock_fd(pcap_t
*);
395 int pcapint_setnonblock_fd(pcap_t
*p
, int);
399 * Internal interfaces for "pcap_create()".
401 * "pcapint_create_interface()" is the routine to do a pcap_create on
402 * a regular network interface. There are multiple implementations
403 * of this, one for each platform type (Linux, BPF, DLPI, etc.),
404 * with the one used chosen by the configure script.
406 * "pcapint_create_common()" allocates and fills in a pcap_t, for use
407 * by pcap_create routines.
409 pcap_t
*pcapint_create_interface(const char *, char *);
411 * A format string for something-only libpcap builds, which use a stub
412 * implementation of pcapint_create_interface(). It contains the substring
413 * "No such device" (one of the standard descriptions of ENODEV) -- this way
414 * tcpdump can detect a particular error condition even though pcap_create()
415 * returns NULL for all errors.
417 #define PCAP_ENODEV_MESSAGE "No such device (this build of libpcap supports %s devices only)."
420 * This wrapper takes an error buffer pointer and a type to use for the
421 * private data, and calls pcapint_create_common(), passing it the error
422 * buffer pointer, the size for the private data type, in bytes, and the
423 * offset of the private data from the beginning of the structure, in
426 #define PCAP_CREATE_COMMON(ebuf, type) \
427 pcapint_create_common(ebuf, \
428 sizeof (struct { pcap_t __common; type __private; }), \
429 offsetof (struct { pcap_t __common; type __private; }, __private))
430 pcap_t
*pcapint_create_common(char *, size_t, size_t);
431 int pcapint_do_addexit(pcap_t
*);
432 void pcapint_add_to_pcaps_to_close(pcap_t
*);
433 void pcapint_remove_from_pcaps_to_close(pcap_t
*);
434 void pcapint_cleanup_live_common(pcap_t
*);
435 int pcapint_check_activated(pcap_t
*);
436 void pcapint_breakloop_common(pcap_t
*);
439 * Internal interfaces for "pcap_findalldevs()".
441 * A pcap_if_list_t * is a reference to a list of devices.
443 * A get_if_flags_func is a platform-dependent function called to get
444 * additional interface flags.
446 * "pcapint_platform_finddevs()" is the platform-dependent routine to
447 * find local network interfaces.
449 * "pcapint_findalldevs_interfaces()" is a helper to find those interfaces
450 * using the "standard" mechanisms (SIOCGIFCONF, "getifaddrs()", etc.).
452 * "pcapint_add_dev()" adds an entry to a pcap_if_list_t.
454 * "pcapint_add_any_dev()" adds an entry for the "any" device to a pcap_if_list_t.
456 * "pcapint_find_dev()" tries to find a device, by name, in a pcap_if_list_t.
458 * "pcapint_find_or_add_dev()" checks whether a device is already in a
459 * pcap_if_list_t and, if not, adds an entry for it.
462 typedef struct pcap_if_list pcap_if_list_t
;
463 typedef int (*get_if_flags_func
)(const char *, bpf_u_int32
*, char *);
464 int pcapint_platform_finddevs(pcap_if_list_t
*, char *);
466 int pcapint_findalldevs_interfaces(pcap_if_list_t
*, char *,
467 int (*)(const char *), get_if_flags_func
);
469 pcap_if_t
*pcapint_find_or_add_dev(pcap_if_list_t
*, const char *, bpf_u_int32
,
470 get_if_flags_func
, const char *, char *);
471 pcap_if_t
*pcapint_find_dev(pcap_if_list_t
*, const char *);
472 pcap_if_t
*pcapint_add_dev(pcap_if_list_t
*, const char *, bpf_u_int32
,
473 const char *, char *);
474 pcap_if_t
*pcapint_add_any_dev(pcap_if_list_t
*, char *);
475 int pcapint_add_addr_to_dev(pcap_if_t
*, struct sockaddr
*, size_t,
476 struct sockaddr
*, size_t, struct sockaddr
*, size_t,
477 struct sockaddr
*dstaddr
, size_t, char *errbuf
);
479 pcap_if_t
*pcapint_find_or_add_if(pcap_if_list_t
*, const char *, uint64_t,
480 get_if_flags_func
, char *);
481 int pcapint_add_addr_to_if(pcap_if_list_t
*, const char *, uint64_t,
483 struct sockaddr
*, size_t, struct sockaddr
*, size_t,
484 struct sockaddr
*, size_t, struct sockaddr
*, size_t, char *);
488 * Internal interfaces for "pcap_open_offline()" and other savefile
491 * "pcapint_open_offline_common()" allocates and fills in a pcap_t, for use
492 * by pcap_open_offline routines.
494 * "pcapint_adjust_snapshot()" adjusts the snapshot to be non-zero and
497 * "pcapint_sf_cleanup()" closes the file handle associated with a pcap_t, if
498 * appropriate, and frees all data common to all modules for handling
501 * "pcapint_charset_fopen()", in UTF-8 mode on Windows, does an fopen() that
502 * treats the pathname as being in UTF-8, rather than the local
503 * code page, on Windows.
507 * This wrapper takes an error buffer pointer and a type to use for the
508 * private data, and calls pcapint_create_common(), passing it the error
509 * buffer pointer, the size for the private data type, in bytes, and the
510 * offset of the private data from the beginning of the structure, in
513 #define PCAP_OPEN_OFFLINE_COMMON(ebuf, type) \
514 pcapint_open_offline_common(ebuf, \
515 sizeof (struct { pcap_t __common; type __private; }), \
516 offsetof (struct { pcap_t __common; type __private; }, __private))
517 pcap_t
*pcapint_open_offline_common(char *ebuf
, size_t total_size
,
518 size_t private_data
);
519 bpf_u_int32
pcapint_adjust_snapshot(bpf_u_int32 linktype
, bpf_u_int32 snaplen
);
520 void pcapint_sf_cleanup(pcap_t
*p
);
522 FILE *pcapint_charset_fopen(const char *path
, const char *mode
);
525 * On other OSes, just use Boring Old fopen().
527 #define pcapint_charset_fopen(path, mode) fopen((path), (mode))
531 * Internal interfaces for loading code at run time.
534 #define pcap_code_handle_t HMODULE
536 pcap_code_handle_t
pcapint_load_code(const char *);
537 void *pcapint_find_function(pcap_code_handle_t
, const char *);
541 * Internal interfaces for doing user-mode filtering of packets and
542 * validating filter programs.
545 * Auxiliary data, for use when interpreting a filter intended for the
546 * Linux kernel when the kernel rejects the filter (requiring us to
547 * run it in userland). It contains VLAN tag information.
549 struct pcap_bpf_aux_data
{
550 u_short vlan_tag_present
;
555 * Filtering routine that takes the auxiliary data as an additional
558 u_int
pcapint_filter_with_aux_data(const struct bpf_insn
*,
559 const u_char
*, u_int
, u_int
, const struct pcap_bpf_aux_data
*);
562 * Filtering routine that doesn't.
564 u_int
pcapint_filter(const struct bpf_insn
*, const u_char
*, u_int
, u_int
);
567 * Routine to validate a BPF program.
569 int pcapint_validate_filter(const struct bpf_insn
*, int);
572 * Internal interfaces for both "pcap_create()" and routines that
575 * "pcapint_oneshot()" is the standard one-shot callback for "pcap_next()"
576 * and "pcap_next_ex()".
578 void pcapint_oneshot(u_char
*, const struct pcap_pkthdr
*, const u_char
*);
580 int pcapint_install_bpf_program(pcap_t
*, struct bpf_program
*);
582 int pcapint_strcasecmp(const char *, const char *);
585 * Internal interfaces for pcap_createsrcstr and pcap_parsesrcstr with
586 * the additional bit of information regarding SSL support (rpcap:// vs.
589 int pcapint_createsrcstr_ex(char *, int, const char *, const char *,
590 const char *, const char *, unsigned char, char *);
591 int pcapint_parsesrcstr_ex(const char *, int *, char *, char *,
592 char *, char *, unsigned char *, char *);
595 extern int pcap_debug
;