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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 <stddef.h>
38
39 #include <signal.h>
40
41 #include <pcap/pcap.h>
42
43 #include "varattrs.h"
44 #include "fmtutils.h"
45
46 #include <stdarg.h>
47
48 #include "portability.h"
49
50 #define PCAP_DEBUG {printf(" [%s:%d %s] ", __FILE__, __LINE__, __func__); fflush(stdout);}
51
52 /*
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.
55 *
56 * XXX - verify that we have at least C99 support on UN*Xes?
57 *
58 * What about MinGW? We're currently assuming
59 * sufficient C99 support there.
60 */
61 #if defined(_MSC_VER)
62 /*
63 * Compiler is MSVC. Make sure we have VS 2015 or later.
64 */
65 #if _MSC_VER < 1900
66 #error "Building libpcap requires VS 2015 or later"
67 #endif
68 #endif
69
70 /*
71 * Version string.
72 * Uses PACKAGE_VERSION from config.h.
73 */
74 #define PCAP_VERSION_STRING "libpcap version " PACKAGE_VERSION
75
76 #ifdef __cplusplus
77 extern "C" {
78 #endif
79
80 /*
81 * If pcapint_new_api is set, we disable pcap_lookupdev(), because:
82 *
83 * it's not thread-safe, and is marked as deprecated, on all
84 * platforms;
85 *
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
91 * end of the string.
92 *
93 * We keep it around in legacy mode for compatibility.
94 *
95 * We also disable the aforementioned hack in pcap_create().
96 */
97 extern int pcapint_new_api;
98
99 /*
100 * If pcapint_utf_8_mode is set, on Windows we treat strings as UTF-8.
101 *
102 * On UN*Xes, we assume all strings are and should be in UTF-8, regardless
103 * of the setting of this flag.
104 */
105 extern int pcapint_utf_8_mode;
106
107 /*
108 * Map packet buffers with 32-bit addresses.
109 */
110 extern int pcapint_mmap_32bit;
111
112 /*
113 * Maximum snapshot length.
114 *
115 * Somewhat arbitrary, but chosen to be:
116 *
117 * 1) big enough for maximum-size Linux loopback packets (65549)
118 * and some USB packets captured with USBPcap:
119 *
120 * https://desowin.org/usbpcap/
121 *
122 * (> 131072, < 262144)
123 *
124 * and
125 *
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.)
135 *
136 * We don't enforce this in pcap_set_snaplen(), but we use it internally.
137 */
138 #define MAXIMUM_SNAPLEN 262144
139
140 /*
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.
144 */
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'))
151
152 struct pcap_opt {
153 char *device;
154 int timeout; /* timeout for buffering */
155 u_int buffer_size;
156 int promisc;
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" */
160 int tstamp_type;
161 int tstamp_precision;
162
163 /*
164 * Platform-dependent options.
165 */
166 #ifdef __linux__
167 int protocol; /* protocol to use when creating PF_PACKET socket */
168 #endif
169 #ifdef _WIN32
170 int nocapture_local;/* disable NPF loopback */
171 #endif
172 };
173
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 *);
187 #ifdef _WIN32
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);
199 #endif
200 typedef void (*cleanup_op_t)(pcap_t *);
201
202 /*
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.
205 */
206 struct pcap {
207 /*
208 * Method to call to read packets on a live capture.
209 */
210 read_op_t read_op;
211
212 /*
213 * Method to call to read the next packet from a savefile.
214 */
215 next_packet_op_t next_packet_op;
216
217 #ifdef _WIN32
218 HANDLE handle;
219 #else
220 int fd;
221 #endif /* _WIN32 */
222
223 /*
224 * Read buffer.
225 */
226 u_int bufsize;
227 u_char *buffer;
228 u_char *bp;
229 u_int cc;
230
231 sig_atomic_t break_loop; /* flag set to force break from packet-reading loop */
232
233 void *priv; /* private data for methods */
234
235 #ifdef ENABLE_REMOTE
236 struct pcap_samp rmt_samp; /* parameters related to the sampling process. */
237 #endif
238
239 int swapped;
240 FILE *rfile; /* null if live capture, non-null if savefile */
241 u_int fddipad;
242 struct pcap *next; /* list of open pcaps that need stuff cleared on close */
243
244 /*
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
248 * always did.
249 */
250 int version_major;
251 int version_minor;
252
253 int snapshot;
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() */
259
260 struct pcap_opt opt;
261
262 /*
263 * Place holder for pcap_next().
264 */
265 u_char *pkt;
266
267 #ifdef _WIN32
268 struct pcap_stat stat; /* used for pcap_stats_ex() */
269 #endif
270
271 /* We're accepting only packets in this direction/these directions. */
272 pcap_direction_t direction;
273
274 /*
275 * Flags to affect BPF code generation.
276 */
277 int bpf_codegen_flags;
278
279 #if !defined(_WIN32)
280 int selectable_fd; /* FD on which select()/poll()/epoll_wait()/kevent()/etc. can be done */
281
282 /*
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.
292 */
293 const struct timeval *required_select_timeout;
294 #endif
295
296 /*
297 * Placeholder for filter code if bpf not in kernel.
298 */
299 struct bpf_program fcode;
300
301 char errbuf[PCAP_ERRBUF_SIZE + 1];
302 #ifdef _WIN32
303 char acp_errbuf[PCAP_ERRBUF_SIZE + 1]; /* buffer for local code page error strings */
304 #endif
305 int dlt_count;
306 u_int *dlt_list;
307 int tstamp_type_count;
308 u_int *tstamp_type_list;
309 int tstamp_precision_count;
310 u_int *tstamp_precision_list;
311
312 struct pcap_pkthdr pcap_header; /* This is needed for the pcap_next_ex() to work */
313
314 /*
315 * More methods.
316 */
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;
326 stats_op_t stats_op;
327 breakloop_op_t breakloop_op;
328
329 /*
330 * Routine to use as callback for pcap_next()/pcap_next_ex().
331 */
332 pcap_handler oneshot_callback;
333
334 #ifdef _WIN32
335 /*
336 * These are, at least currently, specific to the Win32 NPF
337 * driver.
338 */
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;
350 #endif
351 cleanup_op_t cleanup_op;
352 };
353
354 /*
355 * BPF code generation flags.
356 */
357 #define BPF_SPECIAL_VLAN_HANDLING 0x00000001 /* special VLAN handling for Linux */
358 /*
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.
362 */
363 #define BPF_SPECIAL_BASIC_HANDLING 0x00000002
364
365 /*
366 * User data structure for the one-shot callback used for pcap_next()
367 * and pcap_next_ex().
368 */
369 struct oneshot_userdata {
370 struct pcap_pkthdr *hdr;
371 const u_char **pkt;
372 pcap_t *pd;
373 };
374
375 #ifndef min
376 #define min(a, b) ((a) > (b) ? (b) : (a))
377 #endif
378 #ifndef max
379 #define max(a, b) ((a) > (b) ? (a) : (b))
380 #endif
381
382 int pcapint_offline_read(pcap_t *, int, pcap_handler, u_char *);
383
384 /*
385 * Does the packet count argument to a module's read routine say
386 * "supply packets until you run out of packets"?
387 */
388 #define PACKET_COUNT_IS_UNLIMITED(count) ((count) <= 0)
389
390 /*
391 * Routines that most pcap implementations can use for non-blocking mode.
392 */
393 #if !defined(_WIN32)
394 int pcapint_getnonblock_fd(pcap_t *);
395 int pcapint_setnonblock_fd(pcap_t *p, int);
396 #endif
397
398 /*
399 * Internal interfaces for "pcap_create()".
400 *
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.
405 *
406 * "pcapint_create_common()" allocates and fills in a pcap_t, for use
407 * by pcap_create routines.
408 */
409 pcap_t *pcapint_create_interface(const char *, char *);
410 /*
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.
416 */
417 #define PCAP_ENODEV_MESSAGE "No such device (this build of libpcap supports %s devices only)."
418
419 /*
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
424 * bytes.
425 */
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 *);
437
438 /*
439 * Internal interfaces for "pcap_findalldevs()".
440 *
441 * A pcap_if_list_t * is a reference to a list of devices.
442 *
443 * A get_if_flags_func is a platform-dependent function called to get
444 * additional interface flags.
445 *
446 * "pcapint_platform_finddevs()" is the platform-dependent routine to
447 * find local network interfaces.
448 *
449 * "pcapint_findalldevs_interfaces()" is a helper to find those interfaces
450 * using the "standard" mechanisms (SIOCGIFCONF, "getifaddrs()", etc.).
451 *
452 * "pcapint_add_dev()" adds an entry to a pcap_if_list_t.
453 *
454 * "pcapint_add_any_dev()" adds an entry for the "any" device to a pcap_if_list_t.
455 *
456 * "pcapint_find_dev()" tries to find a device, by name, in a pcap_if_list_t.
457 *
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.
460 */
461 struct pcap_if_list;
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 *);
465 #if !defined(_WIN32)
466 int pcapint_findalldevs_interfaces(pcap_if_list_t *, char *,
467 int (*)(const char *), get_if_flags_func);
468 #endif
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);
478 #ifndef _WIN32
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,
482 get_if_flags_func,
483 struct sockaddr *, size_t, struct sockaddr *, size_t,
484 struct sockaddr *, size_t, struct sockaddr *, size_t, char *);
485 #endif
486
487 /*
488 * Internal interfaces for "pcap_open_offline()" and other savefile
489 * I/O routines.
490 *
491 * "pcapint_open_offline_common()" allocates and fills in a pcap_t, for use
492 * by pcap_open_offline routines.
493 *
494 * "pcapint_adjust_snapshot()" adjusts the snapshot to be non-zero and
495 * fit within an int.
496 *
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
499 * savefile types.
500 *
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.
504 */
505
506 /*
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
511 * bytes.
512 */
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);
521 #ifdef _WIN32
522 FILE *pcapint_charset_fopen(const char *path, const char *mode);
523 #else
524 /*
525 * On other OSes, just use Boring Old fopen().
526 */
527 #define pcapint_charset_fopen(path, mode) fopen((path), (mode))
528 #endif
529
530 /*
531 * Internal interfaces for loading code at run time.
532 */
533 #ifdef _WIN32
534 #define pcap_code_handle_t HMODULE
535
536 pcap_code_handle_t pcapint_load_code(const char *);
537 void *pcapint_find_function(pcap_code_handle_t, const char *);
538 #endif
539
540 /*
541 * Internal interfaces for doing user-mode filtering of packets and
542 * validating filter programs.
543 */
544 /*
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.
548 */
549 struct pcap_bpf_aux_data {
550 u_short vlan_tag_present;
551 u_short vlan_tag;
552 };
553
554 /*
555 * Filtering routine that takes the auxiliary data as an additional
556 * argument.
557 */
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 *);
560
561 /*
562 * Filtering routine that doesn't.
563 */
564 u_int pcapint_filter(const struct bpf_insn *, const u_char *, u_int, u_int);
565
566 /*
567 * Routine to validate a BPF program.
568 */
569 int pcapint_validate_filter(const struct bpf_insn *, int);
570
571 /*
572 * Internal interfaces for both "pcap_create()" and routines that
573 * open savefiles.
574 *
575 * "pcapint_oneshot()" is the standard one-shot callback for "pcap_next()"
576 * and "pcap_next_ex()".
577 */
578 void pcapint_oneshot(u_char *, const struct pcap_pkthdr *, const u_char *);
579
580 int pcapint_install_bpf_program(pcap_t *, struct bpf_program *);
581
582 int pcapint_strcasecmp(const char *, const char *);
583
584 /*
585 * Internal interfaces for pcap_createsrcstr and pcap_parsesrcstr with
586 * the additional bit of information regarding SSL support (rpcap:// vs.
587 * rpcaps://).
588 */
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 *);
593
594 #ifdef YYDEBUG
595 extern int pcap_debug;
596 #endif
597
598 #ifdef __cplusplus
599 }
600 #endif
601
602 #endif