1 /* $NetBSD: pcap-usb-linux.c,v 1.8 2024/09/02 15:33:37 christos Exp $ */
2
3 /*
4 * Copyright (c) 2006 Paolo Abeni (Italy)
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote
17 * products derived from this software without specific prior written
18 * permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 *
32 * USB sniffing API implementation for Linux platform
33 * By Paolo Abeni <paolo.abeni@email.it>
34 * Modifications: Kris Katterjohn <katterjohn@gmail.com>
35 *
36 */
37
38 #include <sys/cdefs.h>
39 __RCSID("$NetBSD: pcap-usb-linux.c,v 1.8 2024/09/02 15:33:37 christos Exp $");
40
41 #include <config.h>
42
43 #include "pcap/usb.h"
44 #include "pcap-int.h"
45 #include "pcap-usb-linux.h"
46 #include "pcap-usb-linux-common.h"
47
48 #include "extract.h"
49
50 #ifdef NEED_STRERROR_H
51 #include "strerror.h"
52 #endif
53
54 #include <errno.h>
55 #include <stdlib.h>
56 #include <unistd.h>
57 #include <fcntl.h>
58 #include <limits.h>
59 #include <string.h>
60 #include <dirent.h>
61 #ifdef __linux__
62 #include <byteswap.h>
63 #endif
64 #include <netinet/in.h>
65 #include <sys/ioctl.h>
66 #include <sys/mman.h>
67 #include <sys/utsname.h>
68 #ifdef HAVE_LINUX_USBDEVICE_FS_H
69 /*
70 * We might need <linux/compiler.h> to define __user for
71 * <linux/usbdevice_fs.h>.
72 */
73 #ifdef HAVE_LINUX_COMPILER_H
74 #include <linux/compiler.h>
75 #endif /* HAVE_LINUX_COMPILER_H */
76 #include <linux/usbdevice_fs.h>
77 #endif /* HAVE_LINUX_USBDEVICE_FS_H */
78
79 #include "diag-control.h"
80
81 #define USB_IFACE "usbmon"
82
83 #define USBMON_DEV_PREFIX "usbmon"
84 #define USBMON_DEV_PREFIX_LEN (sizeof USBMON_DEV_PREFIX - 1)
85 #define USB_LINE_LEN 4096
86
87 #if __BYTE_ORDER == __LITTLE_ENDIAN
88 #define htols(s) s
89 #define htoll(l) l
90 #define htol64(ll) ll
91 #else
92 #define htols(s) bswap_16(s)
93 #define htoll(l) bswap_32(l)
94 #define htol64(ll) bswap_64(ll)
95 #endif
96
97 struct mon_bin_stats {
98 uint32_t queued;
99 uint32_t dropped;
100 };
101
102 struct mon_bin_get {
103 pcap_usb_header *hdr;
104 void *data;
105 size_t data_len; /* Length of data (can be zero) */
106 };
107
108 struct mon_bin_mfetch {
109 int32_t *offvec; /* Vector of events fetched */
110 int32_t nfetch; /* Number of events to fetch (out: fetched) */
111 int32_t nflush; /* Number of events to flush */
112 };
113
114 #define MON_IOC_MAGIC 0x92
115
116 #define MON_IOCQ_URB_LEN _IO(MON_IOC_MAGIC, 1)
117 #define MON_IOCX_URB _IOWR(MON_IOC_MAGIC, 2, struct mon_bin_hdr)
118 #define MON_IOCG_STATS _IOR(MON_IOC_MAGIC, 3, struct mon_bin_stats)
119 #define MON_IOCT_RING_SIZE _IO(MON_IOC_MAGIC, 4)
120 #define MON_IOCQ_RING_SIZE _IO(MON_IOC_MAGIC, 5)
121 #define MON_IOCX_GET _IOW(MON_IOC_MAGIC, 6, struct mon_bin_get)
122 #define MON_IOCX_MFETCH _IOWR(MON_IOC_MAGIC, 7, struct mon_bin_mfetch)
123 #define MON_IOCH_MFLUSH _IO(MON_IOC_MAGIC, 8)
124
125 #define MON_BIN_SETUP 0x1 /* setup hdr is present*/
126 #define MON_BIN_SETUP_ZERO 0x2 /* setup buffer is not available */
127 #define MON_BIN_DATA_ZERO 0x4 /* data buffer is not available */
128 #define MON_BIN_ERROR 0x8
129
130 /*
131 * Private data for capturing on Linux USB.
132 */
133 struct pcap_usb_linux {
134 u_char *mmapbuf; /* memory-mapped region pointer */
135 size_t mmapbuflen; /* size of region */
136 int bus_index;
137 u_int packets_read;
138 };
139
140 /* forward declaration */
141 static int usb_activate(pcap_t *);
142 static int usb_stats_linux_bin(pcap_t *, struct pcap_stat *);
143 static int usb_read_linux_bin(pcap_t *, int , pcap_handler , u_char *);
144 static int usb_read_linux_mmap(pcap_t *, int , pcap_handler , u_char *);
145 static int usb_inject_linux(pcap_t *, const void *, size_t);
146 static int usb_setdirection_linux(pcap_t *, pcap_direction_t);
147 static void usb_cleanup_linux_mmap(pcap_t *);
148
149 /* facility to add an USB device to the device list*/
150 static int
usb_dev_add(pcap_if_list_t * devlistp,int n,char * err_str)151 usb_dev_add(pcap_if_list_t *devlistp, int n, char *err_str)
152 {
153 char dev_name[10];
154 char dev_descr[30];
155 snprintf(dev_name, 10, USB_IFACE"%d", n);
156 /*
157 * XXX - is there any notion of "up" and "running"?
158 */
159 if (n == 0) {
160 /*
161 * As this refers to all buses, there's no notion of
162 * "connected" vs. "disconnected", as that's a property
163 * that would apply to a particular USB interface.
164 */
165 if (pcapint_add_dev(devlistp, dev_name,
166 PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
167 "Raw USB traffic, all USB buses", err_str) == NULL)
168 return -1;
169 } else {
170 /*
171 * XXX - is there a way to determine whether anything's
172 * plugged into this bus interface or not, and set
173 * PCAP_IF_CONNECTION_STATUS_CONNECTED or
174 * PCAP_IF_CONNECTION_STATUS_DISCONNECTED?
175 */
176 snprintf(dev_descr, 30, "Raw USB traffic, bus number %d", n);
177 if (pcapint_add_dev(devlistp, dev_name, 0, dev_descr, err_str) == NULL)
178 return -1;
179 }
180
181 return 0;
182 }
183
184 int
usb_findalldevs(pcap_if_list_t * devlistp,char * err_str)185 usb_findalldevs(pcap_if_list_t *devlistp, char *err_str)
186 {
187 struct dirent* data;
188 int ret = 0;
189 DIR* dir;
190 int n;
191 char* name;
192
193 /*
194 * We require 2.6.27 or later kernels, so we have binary-mode support.
195 * The devices are of the form /dev/usbmon{N}.
196 * Open /dev and scan it.
197 */
198 dir = opendir("/dev");
199 if (dir != NULL) {
200 while ((ret == 0) && ((data = readdir(dir)) != 0)) {
201 name = data->d_name;
202
203 /*
204 * Is this a usbmon device?
205 */
206 if (strncmp(name, USBMON_DEV_PREFIX,
207 USBMON_DEV_PREFIX_LEN) != 0)
208 continue; /* no */
209
210 /*
211 * What's the device number?
212 */
213 if (sscanf(&name[USBMON_DEV_PREFIX_LEN], "%d", &n) == 0)
214 continue; /* failed */
215
216 ret = usb_dev_add(devlistp, n, err_str);
217 }
218
219 closedir(dir);
220 }
221 return 0;
222 }
223
224 /*
225 * Matches what's in mon_bin.c in the Linux kernel.
226 */
227 #define MIN_RING_SIZE (8*1024)
228 #define MAX_RING_SIZE (1200*1024)
229
230 static int
usb_set_ring_size(pcap_t * handle,int header_size)231 usb_set_ring_size(pcap_t* handle, int header_size)
232 {
233 /*
234 * A packet from binary usbmon has:
235 *
236 * 1) a fixed-length header, of size header_size;
237 * 2) descriptors, for isochronous transfers;
238 * 3) the payload.
239 *
240 * The kernel buffer has a size, defaulting to 300KB, with a
241 * minimum of 8KB and a maximum of 1200KB. The size is set with
242 * the MON_IOCT_RING_SIZE ioctl; the size passed in is rounded up
243 * to a page size.
244 *
245 * No more than {buffer size}/5 bytes worth of payload is saved.
246 * Therefore, if we subtract the fixed-length size from the
247 * snapshot length, we have the biggest payload we want (we
248 * don't worry about the descriptors - if we have descriptors,
249 * we'll just discard the last bit of the payload to get it
250 * to fit). We multiply that result by 5 and set the buffer
251 * size to that value.
252 */
253 int ring_size;
254
255 if (handle->snapshot < header_size)
256 handle->snapshot = header_size;
257 /* The maximum snapshot size is small enough that this won't overflow */
258 ring_size = (handle->snapshot - header_size) * 5;
259
260 /*
261 * Will this get an error?
262 * (There's no way to query the minimum or maximum, so we just
263 * copy the value from the kernel source. We don't round it
264 * up to a multiple of the page size.)
265 */
266 if (ring_size > MAX_RING_SIZE) {
267 /*
268 * Yes. Lower the ring size to the maximum, and set the
269 * snapshot length to the value that would give us a
270 * maximum-size ring.
271 */
272 ring_size = MAX_RING_SIZE;
273 handle->snapshot = header_size + (MAX_RING_SIZE/5);
274 } else if (ring_size < MIN_RING_SIZE) {
275 /*
276 * Yes. Raise the ring size to the minimum, but leave
277 * the snapshot length unchanged, so we show the
278 * callback no more data than specified by the
279 * snapshot length.
280 */
281 ring_size = MIN_RING_SIZE;
282 }
283
284 if (ioctl(handle->fd, MON_IOCT_RING_SIZE, ring_size) == -1) {
285 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
286 errno, "Can't set ring size from fd %d", handle->fd);
287 return -1;
288 }
289 return ring_size;
290 }
291
292 static
usb_mmap(pcap_t * handle)293 int usb_mmap(pcap_t* handle)
294 {
295 struct pcap_usb_linux *handlep = handle->priv;
296 int len;
297
298 /*
299 * Attempt to set the ring size as appropriate for the snapshot
300 * length, reducing the snapshot length if that'd make the ring
301 * bigger than the kernel supports.
302 */
303 len = usb_set_ring_size(handle, (int)sizeof(pcap_usb_header_mmapped));
304 if (len == -1) {
305 /* Failed. Fall back on non-memory-mapped access. */
306 return 0;
307 }
308
309 handlep->mmapbuflen = len;
310 handlep->mmapbuf = mmap(0, handlep->mmapbuflen, PROT_READ,
311 MAP_SHARED, handle->fd, 0);
312 if (handlep->mmapbuf == MAP_FAILED) {
313 /*
314 * Failed. We don't treat that as a fatal error, we
315 * just try to fall back on non-memory-mapped access.
316 */
317 return 0;
318 }
319 return 1;
320 }
321
322 #ifdef HAVE_LINUX_USBDEVICE_FS_H
323
324 #define CTRL_TIMEOUT (5*1000) /* milliseconds */
325
326 #define USB_DIR_IN 0x80
327 #define USB_TYPE_STANDARD 0x00
328 #define USB_RECIP_DEVICE 0x00
329
330 #define USB_REQ_GET_DESCRIPTOR 6
331
332 #define USB_DT_DEVICE 1
333 #define USB_DT_CONFIG 2
334
335 #define USB_DEVICE_DESCRIPTOR_SIZE 18
336 #define USB_CONFIG_DESCRIPTOR_SIZE 9
337
338 /* probe the descriptors of the devices attached to the bus */
339 /* the descriptors will end up in the captured packet stream */
340 /* and be decoded by external apps like wireshark */
341 /* without these identifying probes packet data can't be fully decoded */
342 static void
probe_devices(int bus)343 probe_devices(int bus)
344 {
345 struct usbdevfs_ctrltransfer ctrl;
346 struct dirent* data;
347 int ret = 0;
348 char busdevpath[sizeof("/dev/bus/usb/000/") + NAME_MAX];
349 DIR* dir;
350 uint8_t descriptor[USB_DEVICE_DESCRIPTOR_SIZE];
351 uint8_t configdesc[USB_CONFIG_DESCRIPTOR_SIZE];
352
353 /* scan usb bus directories for device nodes */
354 snprintf(busdevpath, sizeof(busdevpath), "/dev/bus/usb/%03d", bus);
355 dir = opendir(busdevpath);
356 if (!dir)
357 return;
358
359 while ((ret >= 0) && ((data = readdir(dir)) != 0)) {
360 int fd;
361 char* name = data->d_name;
362
363 if (name[0] == '.')
364 continue;
365
366 snprintf(busdevpath, sizeof(busdevpath), "/dev/bus/usb/%03d/%s", bus, data->d_name);
367
368 fd = open(busdevpath, O_RDWR);
369 if (fd == -1)
370 continue;
371
372 /*
373 * Sigh. Different kernels have different member names
374 * for this structure.
375 */
376 #ifdef HAVE_STRUCT_USBDEVFS_CTRLTRANSFER_BREQUESTTYPE
377 ctrl.bRequestType = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
378 ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
379 ctrl.wValue = USB_DT_DEVICE << 8;
380 ctrl.wIndex = 0;
381 ctrl.wLength = sizeof(descriptor);
382 #else
383 ctrl.requesttype = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
384 ctrl.request = USB_REQ_GET_DESCRIPTOR;
385 ctrl.value = USB_DT_DEVICE << 8;
386 ctrl.index = 0;
387 ctrl.length = sizeof(descriptor);
388 #endif
389 ctrl.data = descriptor;
390 ctrl.timeout = CTRL_TIMEOUT;
391
392 ret = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
393
394 /* Request CONFIGURATION descriptor alone to know wTotalLength */
395 #ifdef HAVE_STRUCT_USBDEVFS_CTRLTRANSFER_BREQUESTTYPE
396 ctrl.wValue = USB_DT_CONFIG << 8;
397 ctrl.wLength = sizeof(configdesc);
398 #else
399 ctrl.value = USB_DT_CONFIG << 8;
400 ctrl.length = sizeof(configdesc);
401 #endif
402 ctrl.data = configdesc;
403 ret = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
404 if (ret >= 0) {
405 uint16_t wtotallength;
406 wtotallength = EXTRACT_LE_U_2(&configdesc[2]);
407 #ifdef HAVE_STRUCT_USBDEVFS_CTRLTRANSFER_BREQUESTTYPE
408 ctrl.wLength = wtotallength;
409 #else
410 ctrl.length = wtotallength;
411 #endif
412 ctrl.data = malloc(wtotallength);
413 if (ctrl.data) {
414 ret = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
415 free(ctrl.data);
416 }
417 }
418 close(fd);
419 }
420 closedir(dir);
421 }
422 #endif /* HAVE_LINUX_USBDEVICE_FS_H */
423
424 pcap_t *
usb_create(const char * device,char * ebuf,int * is_ours)425 usb_create(const char *device, char *ebuf, int *is_ours)
426 {
427 const char *cp;
428 char *cpend;
429 long devnum;
430 pcap_t *p;
431
432 /* Does this look like a USB monitoring device? */
433 cp = strrchr(device, '/');
434 if (cp == NULL)
435 cp = device;
436 /* Does it begin with USB_IFACE? */
437 if (strncmp(cp, USB_IFACE, sizeof USB_IFACE - 1) != 0) {
438 /* Nope, doesn't begin with USB_IFACE */
439 *is_ours = 0;
440 return NULL;
441 }
442 /* Yes - is USB_IFACE followed by a number? */
443 cp += sizeof USB_IFACE - 1;
444 devnum = strtol(cp, &cpend, 10);
445 if (cpend == cp || *cpend != '\0') {
446 /* Not followed by a number. */
447 *is_ours = 0;
448 return NULL;
449 }
450 if (devnum < 0) {
451 /* Followed by a non-valid number. */
452 *is_ours = 0;
453 return NULL;
454 }
455
456 /* OK, it's probably ours. */
457 *is_ours = 1;
458
459 p = PCAP_CREATE_COMMON(ebuf, struct pcap_usb_linux);
460 if (p == NULL)
461 return (NULL);
462
463 p->activate_op = usb_activate;
464 return (p);
465 }
466
467 static int
usb_activate(pcap_t * handle)468 usb_activate(pcap_t* handle)
469 {
470 struct pcap_usb_linux *handlep = handle->priv;
471 char full_path[USB_LINE_LEN];
472
473 /*
474 * Turn a negative snapshot value (invalid), a snapshot value of
475 * 0 (unspecified), or a value bigger than the normal maximum
476 * value, into the maximum allowed value.
477 *
478 * If some application really *needs* a bigger snapshot
479 * length, we should just increase MAXIMUM_SNAPLEN.
480 */
481 if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
482 handle->snapshot = MAXIMUM_SNAPLEN;
483
484 /* Initialize some components of the pcap structure. */
485 handle->bufsize = handle->snapshot;
486 handle->offset = 0;
487 handle->linktype = DLT_USB_LINUX;
488
489 handle->inject_op = usb_inject_linux;
490 handle->setfilter_op = pcapint_install_bpf_program; /* no kernel filtering */
491 handle->setdirection_op = usb_setdirection_linux;
492 handle->set_datalink_op = NULL; /* can't change data link type */
493 handle->getnonblock_op = pcapint_getnonblock_fd;
494 handle->setnonblock_op = pcapint_setnonblock_fd;
495
496 /*get usb bus index from device name */
497 if (sscanf(handle->opt.device, USB_IFACE"%d", &handlep->bus_index) != 1)
498 {
499 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
500 "Can't get USB bus index from %s", handle->opt.device);
501 return PCAP_ERROR;
502 }
503
504 /*
505 * We require 2.6.27 or later kernels, so we have binary-mode support.
506 * Try to open the binary interface.
507 */
508 snprintf(full_path, USB_LINE_LEN, "/dev/"USBMON_DEV_PREFIX"%d",
509 handlep->bus_index);
510 handle->fd = open(full_path, O_RDONLY, 0);
511 if (handle->fd < 0)
512 {
513 /*
514 * The attempt failed; why?
515 */
516 switch (errno) {
517
518 case ENOENT:
519 /*
520 * The device doesn't exist.
521 * That could either mean that there's
522 * no support for monitoring USB buses
523 * (which probably means "the usbmon
524 * module isn't loaded") or that there
525 * is but that *particular* device
526 * doesn't exist (no "scan all buses"
527 * device if the bus index is 0, no
528 * such bus if the bus index isn't 0).
529 *
530 * For now, don't provide an error message;
531 * if we can determine what the particular
532 * problem is, we should report that.
533 */
534 handle->errbuf[0] = '\0';
535 return PCAP_ERROR_NO_SUCH_DEVICE;
536
537 case EACCES:
538 /*
539 * We didn't have permission to open it.
540 */
541 DIAG_OFF_FORMAT_TRUNCATION
542 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
543 "Attempt to open %s failed with EACCES - root privileges may be required",
544 full_path);
545 DIAG_ON_FORMAT_TRUNCATION
546 return PCAP_ERROR_PERM_DENIED;
547
548 default:
549 /*
550 * Something went wrong.
551 */
552 pcapint_fmt_errmsg_for_errno(handle->errbuf,
553 PCAP_ERRBUF_SIZE, errno,
554 "Can't open USB bus file %s", full_path);
555 return PCAP_ERROR;
556 }
557 }
558
559 if (handle->opt.rfmon)
560 {
561 /*
562 * Monitor mode doesn't apply to USB devices.
563 */
564 close(handle->fd);
565 return PCAP_ERROR_RFMON_NOTSUP;
566 }
567
568 /* try to use fast mmap access */
569 if (usb_mmap(handle))
570 {
571 /* We succeeded. */
572 handle->linktype = DLT_USB_LINUX_MMAPPED;
573 handle->stats_op = usb_stats_linux_bin;
574 handle->read_op = usb_read_linux_mmap;
575 handle->cleanup_op = usb_cleanup_linux_mmap;
576 #ifdef HAVE_LINUX_USBDEVICE_FS_H
577 probe_devices(handlep->bus_index);
578 #endif
579
580 /*
581 * "handle->fd" is a real file, so
582 * "select()" and "poll()" work on it.
583 */
584 handle->selectable_fd = handle->fd;
585 return 0;
586 }
587
588 /*
589 * We failed; try plain binary interface access.
590 *
591 * Attempt to set the ring size as appropriate for
592 * the snapshot length, reducing the snapshot length
593 * if that'd make the ring bigger than the kernel
594 * supports.
595 */
596 if (usb_set_ring_size(handle, (int)sizeof(pcap_usb_header)) == -1) {
597 /* Failed. */
598 close(handle->fd);
599 return PCAP_ERROR;
600 }
601 handle->stats_op = usb_stats_linux_bin;
602 handle->read_op = usb_read_linux_bin;
603 #ifdef HAVE_LINUX_USBDEVICE_FS_H
604 probe_devices(handlep->bus_index);
605 #endif
606
607 /*
608 * "handle->fd" is a real file, so "select()" and "poll()"
609 * work on it.
610 */
611 handle->selectable_fd = handle->fd;
612
613 /* for plain binary access and text access we need to allocate the read
614 * buffer */
615 handle->buffer = malloc(handle->bufsize);
616 if (!handle->buffer) {
617 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
618 errno, "malloc");
619 close(handle->fd);
620 return PCAP_ERROR;
621 }
622 return 0;
623 }
624
625 static int
usb_inject_linux(pcap_t * handle,const void * buf _U_,size_t size _U_)626 usb_inject_linux(pcap_t *handle, const void *buf _U_, size_t size _U_)
627 {
628 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
629 "Packet injection is not supported on USB devices");
630 return (-1);
631 }
632
633 static int
usb_setdirection_linux(pcap_t * p,pcap_direction_t d)634 usb_setdirection_linux(pcap_t *p, pcap_direction_t d)
635 {
636 /*
637 * It's guaranteed, at this point, that d is a valid
638 * direction value.
639 */
640 p->direction = d;
641 return 0;
642 }
643
644 static int
usb_stats_linux_bin(pcap_t * handle,struct pcap_stat * stats)645 usb_stats_linux_bin(pcap_t *handle, struct pcap_stat *stats)
646 {
647 struct pcap_usb_linux *handlep = handle->priv;
648 int ret;
649 struct mon_bin_stats st;
650 ret = ioctl(handle->fd, MON_IOCG_STATS, &st);
651 if (ret < 0)
652 {
653 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
654 errno, "Can't read stats from fd %d", handle->fd);
655 return -1;
656 }
657
658 stats->ps_recv = handlep->packets_read + st.queued;
659 stats->ps_drop = st.dropped;
660 stats->ps_ifdrop = 0;
661 return 0;
662 }
663
664 /*
665 * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
666 * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
667 */
668 static int
usb_read_linux_bin(pcap_t * handle,int max_packets _U_,pcap_handler callback,u_char * user)669 usb_read_linux_bin(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
670 {
671 struct pcap_usb_linux *handlep = handle->priv;
672 struct mon_bin_get info;
673 int ret;
674 struct pcap_pkthdr pkth;
675 u_int clen = handle->snapshot - sizeof(pcap_usb_header);
676
677 /* the usb header is going to be part of 'packet' data*/
678 info.hdr = (pcap_usb_header*) handle->buffer;
679 info.data = (u_char *)handle->buffer + sizeof(pcap_usb_header);
680 info.data_len = clen;
681
682 /* ignore interrupt system call errors */
683 do {
684 ret = ioctl(handle->fd, MON_IOCX_GET, &info);
685 if (handle->break_loop)
686 {
687 handle->break_loop = 0;
688 return -2;
689 }
690 } while ((ret == -1) && (errno == EINTR));
691 if (ret < 0)
692 {
693 if (errno == EAGAIN)
694 return 0; /* no data there */
695
696 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
697 errno, "Can't read from fd %d", handle->fd);
698 return -1;
699 }
700
701 /*
702 * info.hdr->data_len is the number of bytes of isochronous
703 * descriptors (if any) plus the number of bytes of data
704 * provided. There are no isochronous descriptors here,
705 * because we're using the old 48-byte header.
706 *
707 * If info.hdr->data_flag is non-zero, there's no URB data;
708 * info.hdr->urb_len is the size of the buffer into which
709 * data is to be placed; it does not represent the amount
710 * of data transferred. If info.hdr->data_flag is zero,
711 * there is URB data, and info.hdr->urb_len is the number
712 * of bytes transmitted or received; it doesn't include
713 * isochronous descriptors.
714 *
715 * The kernel may give us more data than the snaplen; if it did,
716 * reduce the data length so that the total number of bytes we
717 * tell our client we have is not greater than the snaplen.
718 */
719 if (info.hdr->data_len < clen)
720 clen = info.hdr->data_len;
721 info.hdr->data_len = clen;
722 pkth.caplen = sizeof(pcap_usb_header) + clen;
723 if (info.hdr->data_flag) {
724 /*
725 * No data; just base the original length on
726 * info.hdr->data_len (so that it's >= the captured
727 * length).
728 */
729 pkth.len = sizeof(pcap_usb_header) + info.hdr->data_len;
730 } else {
731 /*
732 * We got data; base the original length on
733 * info.hdr->urb_len, so that it includes data
734 * discarded by the USB monitor device due to
735 * its buffer being too small.
736 */
737 pkth.len = sizeof(pcap_usb_header) + info.hdr->urb_len;
738 }
739 pkth.ts.tv_sec = (time_t)info.hdr->ts_sec;
740 pkth.ts.tv_usec = info.hdr->ts_usec;
741
742 if (handle->fcode.bf_insns == NULL ||
743 pcapint_filter(handle->fcode.bf_insns, handle->buffer,
744 pkth.len, pkth.caplen)) {
745 handlep->packets_read++;
746 callback(user, &pkth, handle->buffer);
747 return 1;
748 }
749
750 return 0; /* didn't pass filter */
751 }
752
753 /*
754 * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
755 * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
756 */
757 #define VEC_SIZE 32
758 static int
usb_read_linux_mmap(pcap_t * handle,int max_packets,pcap_handler callback,u_char * user)759 usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
760 {
761 struct pcap_usb_linux *handlep = handle->priv;
762 struct mon_bin_mfetch fetch;
763 int32_t vec[VEC_SIZE];
764 struct pcap_pkthdr pkth;
765 u_char *bp;
766 pcap_usb_header_mmapped* hdr;
767 int nflush = 0;
768 int packets = 0;
769 u_int clen, max_clen;
770
771 max_clen = handle->snapshot - sizeof(pcap_usb_header_mmapped);
772
773 for (;;) {
774 int i, ret;
775 int limit;
776
777 if (PACKET_COUNT_IS_UNLIMITED(max_packets)) {
778 /*
779 * There's no limit on the number of packets
780 * to process, so try to fetch VEC_SIZE packets.
781 */
782 limit = VEC_SIZE;
783 } else {
784 /*
785 * Try to fetch as many packets as we have left
786 * to process, or VEC_SIZE packets, whichever
787 * is less.
788 *
789 * At this point, max_packets > 0 (otherwise,
790 * PACKET_COUNT_IS_UNLIMITED(max_packets)
791 * would be true) and max_packets > packets
792 * (packet starts out as 0, and the test
793 * at the bottom of the loop exits if
794 * max_packets <= packets), so limit is
795 * guaranteed to be > 0.
796 */
797 limit = max_packets - packets;
798 if (limit > VEC_SIZE)
799 limit = VEC_SIZE;
800 }
801
802 /*
803 * Try to fetch as many events as possible, up to
804 * the limit, and flush the events we've processed
805 * earlier (nflush) - MON_IOCX_MFETCH does both
806 * (presumably to reduce the number of system
807 * calls in loops like this).
808 */
809 fetch.offvec = vec;
810 fetch.nfetch = limit;
811 fetch.nflush = nflush;
812 /* ignore interrupt system call errors */
813 do {
814 ret = ioctl(handle->fd, MON_IOCX_MFETCH, &fetch);
815 if (handle->break_loop)
816 {
817 handle->break_loop = 0;
818 return -2;
819 }
820 } while ((ret == -1) && (errno == EINTR));
821 if (ret < 0)
822 {
823 if (errno == EAGAIN)
824 return 0; /* no data there */
825
826 pcapint_fmt_errmsg_for_errno(handle->errbuf,
827 PCAP_ERRBUF_SIZE, errno, "Can't mfetch fd %d",
828 handle->fd);
829 return -1;
830 }
831
832 /* keep track of processed events, we will flush them later */
833 nflush = fetch.nfetch;
834 for (i=0; i<fetch.nfetch; ++i) {
835 /*
836 * XXX - we can't check break_loop here, as
837 * we read the indices of packets into a
838 * local variable, so if we're later called
839 * to fetch more packets, those packets will
840 * not be seen - and won't be flushed, either.
841 *
842 * Instead, we would have to keep the array
843 * of indices in our private data, along
844 * with the count of packets to flush - or
845 * would have to flush the already-processed
846 * packets if we break out of the loop here.
847 */
848
849 /* Get a pointer to this packet's buffer */
850 bp = &handlep->mmapbuf[vec[i]];
851
852 /* That begins with a metadata header */
853 hdr = (pcap_usb_header_mmapped*) bp;
854
855 /* discard filler */
856 if (hdr->event_type == '@')
857 continue;
858
859 /*
860 * hdr->data_len is the number of bytes of
861 * isochronous descriptors (if any) plus the
862 * number of bytes of data provided.
863 *
864 * If hdr->data_flag is non-zero, there's no
865 * URB data; hdr->urb_len is the size of the
866 * buffer into which data is to be placed; it does
867 * not represent the amount of data transferred.
868 * If hdr->data_flag is zero, there is URB data,
869 * and hdr->urb_len is the number of bytes
870 * transmitted or received; it doesn't include
871 * isochronous descriptors.
872 *
873 * The kernel may give us more data than the
874 * snaplen; if it did, reduce the data length
875 * so that the total number of bytes we
876 * tell our client we have is not greater than
877 * the snaplen.
878 */
879 clen = max_clen;
880 if (hdr->data_len < clen)
881 clen = hdr->data_len;
882 pkth.caplen = sizeof(pcap_usb_header_mmapped) + clen;
883 if (hdr->data_flag) {
884 /*
885 * No data; just base the original length
886 * on hdr->data_len (so that it's >= the
887 * captured length). Clamp the result
888 * at UINT_MAX, so it fits in an unsigned
889 * int.
890 */
891 pkth.len = u_int_sum(sizeof(pcap_usb_header_mmapped),
892 hdr->data_len);
893 } else {
894 /*
895 * We got data.
896 */
897 if (is_isochronous_transfer_completion(hdr)) {
898 /*
899 * For isochronous transfer completion
900 * events, hdr->urb_len doesn't take
901 * into account the way the data is
902 * put into the buffer, as it doesn't
903 * count any padding between the
904 * chunks of isochronous data, so
905 * we have to calculate the amount
906 * of data from the isochronous
907 * descriptors.
908 */
909 pkth.len = incoming_isochronous_transfer_completed_len(&pkth, bp);
910 } else {
911 /*
912 * For everything else, the original
913 * data length is just the length of
914 * the memory-mapped Linux USB header
915 * plus hdr->urb_len; we use
916 * hdr->urb_len so that it includes
917 * data discarded by the USB monitor
918 * device due to its buffer being
919 * too small. Clamp the result at
920 * UINT_MAX, so it fits in an
921 * unsigned int.
922 */
923 pkth.len = u_int_sum(sizeof(pcap_usb_header_mmapped),
924 hdr->urb_len);
925 }
926 }
927 pkth.ts.tv_sec = (time_t)hdr->ts_sec;
928 pkth.ts.tv_usec = hdr->ts_usec;
929
930 if (handle->fcode.bf_insns == NULL ||
931 pcapint_filter(handle->fcode.bf_insns, (u_char*) hdr,
932 pkth.len, pkth.caplen)) {
933 handlep->packets_read++;
934 callback(user, &pkth, (u_char*) hdr);
935 packets++;
936 }
937 }
938
939 /*
940 * If max_packets specifies "unlimited", we stop after
941 * the first chunk.
942 */
943 if (PACKET_COUNT_IS_UNLIMITED(max_packets) ||
944 (packets >= max_packets))
945 break;
946 }
947
948 /* flush pending events*/
949 if (ioctl(handle->fd, MON_IOCH_MFLUSH, nflush) == -1) {
950 pcapint_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
951 errno, "Can't mflush fd %d", handle->fd);
952 return -1;
953 }
954 return packets;
955 }
956
957 static void
usb_cleanup_linux_mmap(pcap_t * handle)958 usb_cleanup_linux_mmap(pcap_t* handle)
959 {
960 struct pcap_usb_linux *handlep = handle->priv;
961
962 /* if we have a memory-mapped buffer, unmap it */
963 if (handlep->mmapbuf != NULL) {
964 munmap(handlep->mmapbuf, handlep->mmapbuflen);
965 handlep->mmapbuf = NULL;
966 }
967 pcapint_cleanup_live_common(handle);
968 }
969