contrib/libpcap/pcap-usb-linux.c

   1 /*
   2  * Copyright (c) 2006 Paolo Abeni (Italy)
   3  * 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  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote
  15  * products derived from this software without specific prior written
  16  * permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  *
  30  * USB sniffing API implementation for Linux platform
  31  * By Paolo Abeni <paolo.abeni@email.it>
  32  * Modifications: Kris Katterjohn <katterjohn@gmail.com>
  33  *
  34  */
  35
  36 #ifdef HAVE_CONFIG_H
  37 #include <config.h>
  38 #endif
  39
  40 #include "pcap-int.h"
  41 #include "pcap-usb-linux.h"
  42 #include "pcap/usb.h"
  43
  44 #ifdef NEED_STRERROR_H
  45 #include "strerror.h"
  46 #endif
  47
  48 #include <ctype.h>
  49 #include <errno.h>
  50 #include <stdlib.h>
  51 #include <unistd.h>
  52 #include <fcntl.h>
  53 #include <limits.h>
  54 #include <string.h>
  55 #include <dirent.h>
  56 #include <byteswap.h>
  57 #include <netinet/in.h>
  58 #include <sys/ioctl.h>
  59 #include <sys/mman.h>
  60 #include <sys/utsname.h>
  61 #ifdef HAVE_LINUX_USBDEVICE_FS_H
  62 /*
  63  * We might need <linux/compiler.h> to define __user for
  64  * <linux/usbdevice_fs.h>.
  65  */
  66 #ifdef HAVE_LINUX_COMPILER_H
  67 #include <linux/compiler.h>
  68 #endif /* HAVE_LINUX_COMPILER_H */
  69 #include <linux/usbdevice_fs.h>
  70 #endif /* HAVE_LINUX_USBDEVICE_FS_H */
  71
  72 #define USB_IFACE "usbmon"
  73 #define USB_TEXT_DIR_OLD "/sys/kernel/debug/usbmon"
  74 #define USB_TEXT_DIR "/sys/kernel/debug/usb/usbmon"
  75 #define SYS_USB_BUS_DIR "/sys/bus/usb/devices"
  76 #define PROC_USB_BUS_DIR "/proc/bus/usb"
  77 #define USB_LINE_LEN 4096
  78
  79 #if __BYTE_ORDER == __LITTLE_ENDIAN
  80 #define htols(s) s
  81 #define htoll(l) l
  82 #define htol64(ll) ll
  83 #else
  84 #define htols(s) bswap_16(s)
  85 #define htoll(l) bswap_32(l)
  86 #define htol64(ll) bswap_64(ll)
  87 #endif
  88
  89 struct mon_bin_stats {
  90         uint32_t queued;
  91         uint32_t dropped;
  92 };
  93
  94 struct mon_bin_get {
  95         pcap_usb_header *hdr;
  96         void *data;
  97         size_t data_len;   /* Length of data (can be zero) */
  98 };
  99
 100 struct mon_bin_mfetch {
 101         int32_t *offvec;   /* Vector of events fetched */
 102         int32_t nfetch;    /* Number of events to fetch (out: fetched) */
 103         int32_t nflush;    /* Number of events to flush */
 104 };
 105
 106 #define MON_IOC_MAGIC 0x92
 107
 108 #define MON_IOCQ_URB_LEN _IO(MON_IOC_MAGIC, 1)
 109 #define MON_IOCX_URB  _IOWR(MON_IOC_MAGIC, 2, struct mon_bin_hdr)
 110 #define MON_IOCG_STATS _IOR(MON_IOC_MAGIC, 3, struct mon_bin_stats)
 111 #define MON_IOCT_RING_SIZE _IO(MON_IOC_MAGIC, 4)
 112 #define MON_IOCQ_RING_SIZE _IO(MON_IOC_MAGIC, 5)
 113 #define MON_IOCX_GET   _IOW(MON_IOC_MAGIC, 6, struct mon_bin_get)
 114 #define MON_IOCX_MFETCH _IOWR(MON_IOC_MAGIC, 7, struct mon_bin_mfetch)
 115 #define MON_IOCH_MFLUSH _IO(MON_IOC_MAGIC, 8)
 116
 117 #define MON_BIN_SETUP   0x1 /* setup hdr is present*/
 118 #define MON_BIN_SETUP_ZERO      0x2 /* setup buffer is not available */
 119 #define MON_BIN_DATA_ZERO       0x4 /* data buffer is not available */
 120 #define MON_BIN_ERROR   0x8
 121
 122 /*
 123  * Private data for capturing on Linux USB.
 124  */
 125 struct pcap_usb_linux {
 126         u_char *mmapbuf;        /* memory-mapped region pointer */
 127         size_t mmapbuflen;      /* size of region */
 128         int bus_index;
 129         u_int packets_read;
 130 };
 131
 132 /* forward declaration */
 133 static int usb_activate(pcap_t *);
 134 static int usb_stats_linux(pcap_t *, struct pcap_stat *);
 135 static int usb_stats_linux_bin(pcap_t *, struct pcap_stat *);
 136 static int usb_read_linux(pcap_t *, int , pcap_handler , u_char *);
 137 static int usb_read_linux_bin(pcap_t *, int , pcap_handler , u_char *);
 138 static int usb_read_linux_mmap(pcap_t *, int , pcap_handler , u_char *);
 139 static int usb_inject_linux(pcap_t *, const void *, size_t);
 140 static int usb_setdirection_linux(pcap_t *, pcap_direction_t);
 141 static void usb_cleanup_linux_mmap(pcap_t *);
 142
 143 static int
 144 have_binary_usbmon(void)
 145 {
 146         struct utsname utsname;
 147         char *version_component, *endp;
 148         int major, minor, subminor;
 149
 150         if (uname(&utsname) == 0) {
 151                 /*
 152                  * 2.6.21 is the first release with the binary-mode
 153                  * USB monitoring.
 154                  */
 155                 version_component = utsname.release;
 156                 major = strtol(version_component, &endp, 10);
 157                 if (endp != version_component && *endp == '.') {
 158                         /*
 159                          * OK, that was a valid major version.
 160                          * Is it 3 or greater?  If so, we have binary
 161                          * mode support.
 162                          */
 163                         if (major >= 3)
 164                                 return 1;
 165
 166                         /*
 167                          * Is it 1 or less?  If so, we don't have binary
 168                          * mode support.  (In fact, we don't have any
 169                          * USB monitoring....)
 170                          */
 171                         if (major <= 1)
 172                                 return 0;
 173                 }
 174
 175                 /*
 176                  * OK, this is a 2.x kernel.
 177                  * What's the minor version?
 178                  */
 179                 version_component = endp + 1;
 180                 minor = strtol(version_component, &endp, 10);
 181                 if (endp != version_component &&
 182                     (*endp == '.' || *endp == '\0')) {
 183                         /*
 184                          * OK, that was a valid minor version.
 185                          * Is is 2.6 or later?  (There shouldn't be a
 186                          * "later", as 2.6.x went to 3.x, but we'll
 187                          * check anyway.)
 188                          */
 189                         if (minor < 6) {
 190                                 /*
 191                                  * No, so no binary support (did 2.4 have
 192                                  * any USB monitoring at all?)
 193                                  */
 194                                 return 0;
 195                         }
 196
 197                         /*
 198                          * OK, this is a 2.6.x kernel.
 199                          * What's the subminor version?
 200                          */
 201                         version_component = endp + 1;
 202                         subminor = strtol(version_component, &endp, 10);
 203                         if (endp != version_component &&
 204                             (*endp == '.' || *endp == '\0')) {
 205                                 /*
 206                                  * OK, that was a valid subminor version.
 207                                  * Is it 21 or greater?
 208                                  */
 209                                 if (subminor >= 21) {
 210                                         /*
 211                                          * Yes - we have binary mode
 212                                          * support.
 213                                          */
 214                                         return 1;
 215                                 }
 216                         }
 217                 }
 218         }
 219
 220         /*
 221          * Either uname() failed, in which case we just say "no binary
 222          * mode support", or we don't have binary mode support.
 223          */
 224         return 0;
 225 }
 226
 227 /* facility to add an USB device to the device list*/
 228 static int
 229 usb_dev_add(pcap_if_list_t *devlistp, int n, char *err_str)
 230 {
 231         char dev_name[10];
 232         char dev_descr[30];
 233         pcap_snprintf(dev_name, 10, USB_IFACE"%d", n);
 234         /*
 235          * XXX - is there any notion of "up" and "running"?
 236          */
 237         if (n == 0) {
 238                 /*
 239                  * As this refers to all buses, there's no notion of
 240                  * "connected" vs. "disconnected", as that's a property
 241                  * that would apply to a particular USB interface.
 242                  */
 243                 if (add_dev(devlistp, dev_name,
 244                     PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE,
 245                     "Raw USB traffic, all USB buses", err_str) == NULL)
 246                         return -1;
 247         } else {
 248                 /*
 249                  * XXX - is there a way to determine whether anything's
 250                  * plugged into this bus interface or not, and set
 251                  * PCAP_IF_CONNECTION_STATUS_CONNECTED or
 252                  * PCAP_IF_CONNECTION_STATUS_DISCONNECTED?
 253                  */
 254                 pcap_snprintf(dev_descr, 30, "Raw USB traffic, bus number %d", n);
 255                 if (add_dev(devlistp, dev_name, 0, dev_descr, err_str) == NULL)
 256                         return -1;
 257         }
 258
 259         return 0;
 260 }
 261
 262 int
 263 usb_findalldevs(pcap_if_list_t *devlistp, char *err_str)
 264 {
 265         char usb_mon_dir[PATH_MAX];
 266         char *usb_mon_prefix;
 267         size_t usb_mon_prefix_len;
 268         struct dirent* data;
 269         int ret = 0;
 270         DIR* dir;
 271         int n;
 272         char* name;
 273         size_t len;
 274
 275         if (have_binary_usbmon()) {
 276                 /*
 277                  * We have binary-mode support.
 278                  * What do the device names look like?
 279                  * Split LINUX_USB_MON_DEV into a directory that we'll
 280                  * scan and a file name prefix that we'll check for.
 281                  */
 282                 pcap_strlcpy(usb_mon_dir, LINUX_USB_MON_DEV, sizeof usb_mon_dir);
 283                 usb_mon_prefix = strrchr(usb_mon_dir, '/');
 284                 if (usb_mon_prefix == NULL) {
 285                         /*
 286                          * This "shouldn't happen".  Just give up if it
 287                          * does.
 288                          */
 289                         return 0;
 290                 }
 291                 *usb_mon_prefix++ = '\0';
 292                 usb_mon_prefix_len = strlen(usb_mon_prefix);
 293
 294                 /*
 295                  * Open the directory and scan it.
 296                  */
 297                 dir = opendir(usb_mon_dir);
 298                 if (dir != NULL) {
 299                         while ((ret == 0) && ((data = readdir(dir)) != 0)) {
 300                                 name = data->d_name;
 301
 302                                 /*
 303                                  * Is this a usbmon device?
 304                                  */
 305                                 if (strncmp(name, usb_mon_prefix, usb_mon_prefix_len) != 0)
 306                                         continue;       /* no */
 307
 308                                 /*
 309                                  * What's the device number?
 310                                  */
 311                                 if (sscanf(&name[usb_mon_prefix_len], "%d", &n) == 0)
 312                                         continue;       /* failed */
 313
 314                                 ret = usb_dev_add(devlistp, n, err_str);
 315                         }
 316
 317                         closedir(dir);
 318                 }
 319                 return 0;
 320         } else {
 321                 /*
 322                  * We have only text mode support.
 323                  * We don't look for the text devices because we can't
 324                  * look for them without root privileges, and we don't
 325                  * want to require root privileges to enumerate devices
 326                  * (we want to let the user to try a device and get
 327                  * an error, rather than seeing no devices and asking
 328                  * "why am I not seeing devices" and forcing a long
 329                  * process of poking to figure out whether it's "no
 330                  * privileges" or "your kernel is too old" or "the
 331                  * usbmon module isn't loaded" or...).
 332                  *
 333                  * Instead, we look to see what buses we have.
 334                  * If the kernel is so old that it doesn't have
 335                  * binary-mode support, it's also so old that
 336                  * it doesn't have a "scan all buses" device.
 337                  *
 338                  * First, try scanning sysfs USB bus directory.
 339                  */
 340                 dir = opendir(SYS_USB_BUS_DIR);
 341                 if (dir != NULL) {
 342                         while ((ret == 0) && ((data = readdir(dir)) != 0)) {
 343                                 name = data->d_name;
 344
 345                                 if (strncmp(name, "usb", 3) != 0)
 346                                         continue;
 347
 348                                 if (sscanf(&name[3], "%d", &n) == 0)
 349                                         continue;
 350
 351                                 ret = usb_dev_add(devlistp, n, err_str);
 352                         }
 353
 354                         closedir(dir);
 355                         return 0;
 356                 }
 357
 358                 /* That didn't work; try scanning procfs USB bus directory. */
 359                 dir = opendir(PROC_USB_BUS_DIR);
 360                 if (dir != NULL) {
 361                         while ((ret == 0) && ((data = readdir(dir)) != 0)) {
 362                                 name = data->d_name;
 363                                 len = strlen(name);
 364
 365                                 /* if this file name does not end with a number it's not of our interest */
 366                                 if ((len < 1) || !isdigit(name[--len]))
 367                                         continue;
 368                                 while (isdigit(name[--len]));
 369                                 if (sscanf(&name[len+1], "%d", &n) != 1)
 370                                         continue;
 371
 372                                 ret = usb_dev_add(devlistp, n, err_str);
 373                         }
 374
 375                         closedir(dir);
 376                         return ret;
 377                 }
 378
 379                 /* neither of them worked */
 380                 return 0;
 381         }
 382 }
 383
 384 /*
 385  * Matches what's in mon_bin.c in the Linux kernel.
 386  */
 387 #define MIN_RING_SIZE   (8*1024)
 388 #define MAX_RING_SIZE   (1200*1024)
 389
 390 static int
 391 usb_set_ring_size(pcap_t* handle, int header_size)
 392 {
 393         /*
 394          * A packet from binary usbmon has:
 395          *
 396          *  1) a fixed-length header, of size header_size;
 397          *  2) descriptors, for isochronous transfers;
 398          *  3) the payload.
 399          *
 400          * The kernel buffer has a size, defaulting to 300KB, with a
 401          * minimum of 8KB and a maximum of 1200KB.  The size is set with
 402          * the MON_IOCT_RING_SIZE ioctl; the size passed in is rounded up
 403          * to a page size.
 404          *
 405          * No more than {buffer size}/5 bytes worth of payload is saved.
 406          * Therefore, if we subtract the fixed-length size from the
 407          * snapshot length, we have the biggest payload we want (we
 408          * don't worry about the descriptors - if we have descriptors,
 409          * we'll just discard the last bit of the payload to get it
 410          * to fit).  We multiply that result by 5 and set the buffer
 411          * size to that value.
 412          */
 413         int ring_size;
 414
 415         if (handle->snapshot < header_size)
 416                 handle->snapshot = header_size;
 417         /* The maximum snapshot size is small enough that this won't overflow */
 418         ring_size = (handle->snapshot - header_size) * 5;
 419
 420         /*
 421          * Will this get an error?
 422          * (There's no wqy to query the minimum or maximum, so we just
 423          * copy the value from the kernel source.  We don't round it
 424          * up to a multiple of the page size.)
 425          */
 426         if (ring_size > MAX_RING_SIZE) {
 427                 /*
 428                  * Yes.  Lower the ring size to the maximum, and set the
 429                  * snapshot length to the value that would give us a
 430                  * maximum-size ring.
 431                  */
 432                 ring_size = MAX_RING_SIZE;
 433                 handle->snapshot = header_size + (MAX_RING_SIZE/5);
 434         } else if (ring_size < MIN_RING_SIZE) {
 435                 /*
 436                  * Yes.  Raise the ring size to the minimum, but leave
 437                  * the snapshot length unchanged, so we show the
 438                  * callback no more data than specified by the
 439                  * snapshot length.
 440                  */
 441                 ring_size = MIN_RING_SIZE;
 442         }
 443
 444         if (ioctl(handle->fd, MON_IOCT_RING_SIZE, ring_size) == -1) {
 445                 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 446                     errno, "Can't set ring size from fd %d", handle->fd);
 447                 return -1;
 448         }
 449         return ring_size;
 450 }
 451
 452 static
 453 int usb_mmap(pcap_t* handle)
 454 {
 455         struct pcap_usb_linux *handlep = handle->priv;
 456         int len;
 457
 458         /*
 459          * Attempt to set the ring size as appropriate for the snapshot
 460          * length, reducing the snapshot length if that'd make the ring
 461          * bigger than the kernel supports.
 462          */
 463         len = usb_set_ring_size(handle, (int)sizeof(pcap_usb_header_mmapped));
 464         if (len == -1) {
 465                 /* Failed.  Fall back on non-memory-mapped access. */
 466                 return 0;
 467         }
 468
 469         handlep->mmapbuflen = len;
 470         handlep->mmapbuf = mmap(0, handlep->mmapbuflen, PROT_READ,
 471             MAP_SHARED, handle->fd, 0);
 472         if (handlep->mmapbuf == MAP_FAILED) {
 473                 /*
 474                  * Failed.  We don't treat that as a fatal error, we
 475                  * just try to fall back on non-memory-mapped access.
 476                  */
 477                 return 0;
 478         }
 479         return 1;
 480 }
 481
 482 #ifdef HAVE_LINUX_USBDEVICE_FS_H
 483
 484 #define CTRL_TIMEOUT    (5*1000)        /* milliseconds */
 485
 486 #define USB_DIR_IN              0x80
 487 #define USB_TYPE_STANDARD       0x00
 488 #define USB_RECIP_DEVICE        0x00
 489
 490 #define USB_REQ_GET_DESCRIPTOR  6
 491
 492 #define USB_DT_DEVICE           1
 493
 494 /* probe the descriptors of the devices attached to the bus */
 495 /* the descriptors will end up in the captured packet stream */
 496 /* and be decoded by external apps like wireshark */
 497 /* without these identifying probes packet data can't be fully decoded */
 498 static void
 499 probe_devices(int bus)
 500 {
 501         struct usbdevfs_ctrltransfer ctrl;
 502         struct dirent* data;
 503         int ret = 0;
 504         char buf[sizeof("/dev/bus/usb/000/") + NAME_MAX];
 505         DIR* dir;
 506
 507         /* scan usb bus directories for device nodes */
 508         pcap_snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d", bus);
 509         dir = opendir(buf);
 510         if (!dir)
 511                 return;
 512
 513         while ((ret >= 0) && ((data = readdir(dir)) != 0)) {
 514                 int fd;
 515                 char* name = data->d_name;
 516
 517                 if (name[0] == '.')
 518                         continue;
 519
 520                 pcap_snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d/%s", bus, data->d_name);
 521
 522                 fd = open(buf, O_RDWR);
 523                 if (fd == -1)
 524                         continue;
 525
 526                 /*
 527                  * Sigh.  Different kernels have different member names
 528                  * for this structure.
 529                  */
 530 #ifdef HAVE_STRUCT_USBDEVFS_CTRLTRANSFER_BREQUESTTYPE
 531                 ctrl.bRequestType = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
 532                 ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
 533                 ctrl.wValue = USB_DT_DEVICE << 8;
 534                 ctrl.wIndex = 0;
 535                 ctrl.wLength = sizeof(buf);
 536 #else
 537                 ctrl.requesttype = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
 538                 ctrl.request = USB_REQ_GET_DESCRIPTOR;
 539                 ctrl.value = USB_DT_DEVICE << 8;
 540                 ctrl.index = 0;
 541                 ctrl.length = sizeof(buf);
 542 #endif
 543                 ctrl.data = buf;
 544                 ctrl.timeout = CTRL_TIMEOUT;
 545
 546                 ret = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
 547
 548                 close(fd);
 549         }
 550         closedir(dir);
 551 }
 552 #endif /* HAVE_LINUX_USBDEVICE_FS_H */
 553
 554 pcap_t *
 555 usb_create(const char *device, char *ebuf, int *is_ours)
 556 {
 557         const char *cp;
 558         char *cpend;
 559         long devnum;
 560         pcap_t *p;
 561
 562         /* Does this look like a USB monitoring device? */
 563         cp = strrchr(device, '/');
 564         if (cp == NULL)
 565                 cp = device;
 566         /* Does it begin with USB_IFACE? */
 567         if (strncmp(cp, USB_IFACE, sizeof USB_IFACE - 1) != 0) {
 568                 /* Nope, doesn't begin with USB_IFACE */
 569                 *is_ours = 0;
 570                 return NULL;
 571         }
 572         /* Yes - is USB_IFACE followed by a number? */
 573         cp += sizeof USB_IFACE - 1;
 574         devnum = strtol(cp, &cpend, 10);
 575         if (cpend == cp || *cpend != '\0') {
 576                 /* Not followed by a number. */
 577                 *is_ours = 0;
 578                 return NULL;
 579         }
 580         if (devnum < 0) {
 581                 /* Followed by a non-valid number. */
 582                 *is_ours = 0;
 583                 return NULL;
 584         }
 585
 586         /* OK, it's probably ours. */
 587         *is_ours = 1;
 588
 589         p = pcap_create_common(ebuf, sizeof (struct pcap_usb_linux));
 590         if (p == NULL)
 591                 return (NULL);
 592
 593         p->activate_op = usb_activate;
 594         return (p);
 595 }
 596
 597 static int
 598 usb_activate(pcap_t* handle)
 599 {
 600         struct pcap_usb_linux *handlep = handle->priv;
 601         char            full_path[USB_LINE_LEN];
 602         int             ret;
 603
 604         /*
 605          * Turn a negative snapshot value (invalid), a snapshot value of
 606          * 0 (unspecified), or a value bigger than the normal maximum
 607          * value, into the maximum allowed value.
 608          *
 609          * If some application really *needs* a bigger snapshot
 610          * length, we should just increase MAXIMUM_SNAPLEN.
 611          */
 612         if (handle->snapshot <= 0 || handle->snapshot > MAXIMUM_SNAPLEN)
 613                 handle->snapshot = MAXIMUM_SNAPLEN;
 614
 615         /* Initialize some components of the pcap structure. */
 616         handle->bufsize = handle->snapshot;
 617         handle->offset = 0;
 618         handle->linktype = DLT_USB_LINUX;
 619
 620         handle->inject_op = usb_inject_linux;
 621         handle->setfilter_op = install_bpf_program; /* no kernel filtering */
 622         handle->setdirection_op = usb_setdirection_linux;
 623         handle->set_datalink_op = NULL; /* can't change data link type */
 624         handle->getnonblock_op = pcap_getnonblock_fd;
 625         handle->setnonblock_op = pcap_setnonblock_fd;
 626
 627         /*get usb bus index from device name */
 628         if (sscanf(handle->opt.device, USB_IFACE"%d", &handlep->bus_index) != 1)
 629         {
 630                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 631                         "Can't get USB bus index from %s", handle->opt.device);
 632                 return PCAP_ERROR;
 633         }
 634
 635         if (have_binary_usbmon())
 636         {
 637                 /*
 638                  * We have binary-mode support.
 639                  * Try to open the binary interface.
 640                  */
 641                 pcap_snprintf(full_path, USB_LINE_LEN, LINUX_USB_MON_DEV"%d", handlep->bus_index);
 642                 handle->fd = open(full_path, O_RDONLY, 0);
 643                 if (handle->fd < 0)
 644                 {
 645                         /*
 646                          * The attempt failed; why?
 647                          */
 648                         switch (errno) {
 649
 650                         case ENOENT:
 651                                 /*
 652                                  * The device doesn't exist.
 653                                  * That could either mean that there's
 654                                  * no support for monitoring USB buses
 655                                  * (which probably means "the usbmon
 656                                  * module isn't loaded") or that there
 657                                  * is but that *particular* device
 658                                  * doesn't exist (no "scan all buses"
 659                                  * device if the bus index is 0, no
 660                                  * such bus if the bus index isn't 0).
 661                                  */
 662                                 return PCAP_ERROR_NO_SUCH_DEVICE;
 663
 664                         case EACCES:
 665                                 /*
 666                                  * We didn't have permission to open it.
 667                                  */
 668                                 return PCAP_ERROR_PERM_DENIED;
 669
 670                         default:
 671                                 /*
 672                                  * Something went wrong.
 673                                  */
 674                                 pcap_fmt_errmsg_for_errno(handle->errbuf,
 675                                     PCAP_ERRBUF_SIZE, errno,
 676                                     "Can't open USB bus file %s", full_path);
 677                                 return PCAP_ERROR;
 678                         }
 679                 }
 680
 681                 if (handle->opt.rfmon)
 682                 {
 683                         /*
 684                          * Monitor mode doesn't apply to USB devices.
 685                          */
 686                         close(handle->fd);
 687                         return PCAP_ERROR_RFMON_NOTSUP;
 688                 }
 689
 690                 /* try to use fast mmap access */
 691                 if (usb_mmap(handle))
 692                 {
 693                         /* We succeeded. */
 694                         handle->linktype = DLT_USB_LINUX_MMAPPED;
 695                         handle->stats_op = usb_stats_linux_bin;
 696                         handle->read_op = usb_read_linux_mmap;
 697                         handle->cleanup_op = usb_cleanup_linux_mmap;
 698 #ifdef HAVE_LINUX_USBDEVICE_FS_H
 699                         probe_devices(handlep->bus_index);
 700 #endif
 701
 702                         /*
 703                          * "handle->fd" is a real file, so
 704                          * "select()" and "poll()" work on it.
 705                          */
 706                         handle->selectable_fd = handle->fd;
 707                         return 0;
 708                 }
 709
 710                 /*
 711                  * We failed; try plain binary interface access.
 712                  *
 713                  * Attempt to set the ring size as appropriate for
 714                  * the snapshot length, reducing the snapshot length
 715                  * if that'd make the ring bigger than the kernel
 716                  * supports.
 717                  */
 718                 if (usb_set_ring_size(handle, (int)sizeof(pcap_usb_header)) == -1) {
 719                         /* Failed. */
 720                         close(handle->fd);
 721                         return PCAP_ERROR;
 722                 }
 723                 handle->stats_op = usb_stats_linux_bin;
 724                 handle->read_op = usb_read_linux_bin;
 725 #ifdef HAVE_LINUX_USBDEVICE_FS_H
 726                 probe_devices(handlep->bus_index);
 727 #endif
 728         }
 729         else {
 730                 /*
 731                  * We don't have binary mode support.
 732                  * Try opening the text-mode device.
 733                  */
 734                 pcap_snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR"/%dt", handlep->bus_index);
 735                 handle->fd = open(full_path, O_RDONLY, 0);
 736                 if (handle->fd < 0)
 737                 {
 738                         if (errno == ENOENT)
 739                         {
 740                                 /*
 741                                  * Not found at the new location; try
 742                                  * the old location.
 743                                  */
 744                                 pcap_snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR_OLD"/%dt", handlep->bus_index);
 745                                 handle->fd = open(full_path, O_RDONLY, 0);
 746                         }
 747                         if (handle->fd < 0) {
 748                                 if (errno == ENOENT)
 749                                 {
 750                                         /*
 751                                          * The problem is that the file
 752                                          * doesn't exist.  Report that as
 753                                          * "no such device".  (That could
 754                                          * mean "no such USB bus" or
 755                                          * "monitoring not supported".)
 756                                          */
 757                                         ret = PCAP_ERROR_NO_SUCH_DEVICE;
 758                                 }
 759                                 else if (errno == EACCES)
 760                                 {
 761                                         /*
 762                                          * The problem is that we don't
 763                                          * have sufficient permission to
 764                                          * open the file.  Report that.
 765                                          */
 766                                         ret = PCAP_ERROR_PERM_DENIED;
 767                                 }
 768                                 else
 769                                 {
 770                                         /*
 771                                          * Some other error.
 772                                          */
 773                                         ret = PCAP_ERROR;
 774                                 }
 775                                 pcap_fmt_errmsg_for_errno(handle->errbuf,
 776                                     PCAP_ERRBUF_SIZE, errno,
 777                                     "Can't open USB bus file %s",
 778                                     full_path);
 779                                 return ret;
 780                         }
 781                 }
 782
 783                 if (handle->opt.rfmon)
 784                 {
 785                         /*
 786                          * Monitor mode doesn't apply to USB devices.
 787                          */
 788                         close(handle->fd);
 789                         return PCAP_ERROR_RFMON_NOTSUP;
 790                 }
 791
 792                 handle->stats_op = usb_stats_linux;
 793                 handle->read_op = usb_read_linux;
 794         }
 795
 796         /*
 797          * "handle->fd" is a real file, so "select()" and "poll()"
 798          * work on it.
 799          */
 800         handle->selectable_fd = handle->fd;
 801
 802         /* for plain binary access and text access we need to allocate the read
 803          * buffer */
 804         handle->buffer = malloc(handle->bufsize);
 805         if (!handle->buffer) {
 806                 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 807                     errno, "malloc");
 808                 close(handle->fd);
 809                 return PCAP_ERROR;
 810         }
 811         return 0;
 812 }
 813
 814 static inline int
 815 ascii_to_int(char c)
 816 {
 817         return c < 'A' ? c- '0': ((c<'a') ? c - 'A' + 10: c-'a'+10);
 818 }
 819
 820 /*
 821  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 822  * <linux-kernel-source>/drivers/usb/mon/mon_text.c for urb string
 823  * format description
 824  */
 825 static int
 826 usb_read_linux(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
 827 {
 828         /* see:
 829         * /usr/src/linux/Documentation/usb/usbmon.txt
 830         * for message format
 831         */
 832         struct pcap_usb_linux *handlep = handle->priv;
 833         unsigned timestamp;
 834         int tag, cnt, ep_num, dev_addr, dummy, ret, urb_len, data_len;
 835         char etype, pipeid1, pipeid2, status[16], urb_tag, line[USB_LINE_LEN];
 836         char *string = line;
 837         u_char * rawdata = handle->buffer;
 838         struct pcap_pkthdr pkth;
 839         pcap_usb_header* uhdr = (pcap_usb_header*)handle->buffer;
 840         u_char urb_transfer=0;
 841         int incoming=0;
 842
 843         /* ignore interrupt system call errors */
 844         do {
 845                 ret = read(handle->fd, line, USB_LINE_LEN - 1);
 846                 if (handle->break_loop)
 847                 {
 848                         handle->break_loop = 0;
 849                         return -2;
 850                 }
 851         } while ((ret == -1) && (errno == EINTR));
 852         if (ret < 0)
 853         {
 854                 if (errno == EAGAIN)
 855                         return 0;       /* no data there */
 856
 857                 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 858                     errno, "Can't read from fd %d", handle->fd);
 859                 return -1;
 860         }
 861
 862         /* read urb header; %n argument may increment return value, but it's
 863         * not mandatory, so does not count on it*/
 864         string[ret] = 0;
 865         ret = sscanf(string, "%x %d %c %c%c:%d:%d %s%n", &tag, &timestamp, &etype,
 866                 &pipeid1, &pipeid2, &dev_addr, &ep_num, status,
 867                 &cnt);
 868         if (ret < 8)
 869         {
 870                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 871                     "Can't parse USB bus message '%s', too few tokens (expected 8 got %d)",
 872                     string, ret);
 873                 return -1;
 874         }
 875         uhdr->id = tag;
 876         uhdr->device_address = dev_addr;
 877         uhdr->bus_id = handlep->bus_index;
 878         uhdr->status = 0;
 879         string += cnt;
 880
 881         /* don't use usbmon provided timestamp, since it have low precision*/
 882         if (gettimeofday(&pkth.ts, NULL) < 0)
 883         {
 884                 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
 885                     errno, "Can't get timestamp for message '%s'", string);
 886                 return -1;
 887         }
 888         uhdr->ts_sec = pkth.ts.tv_sec;
 889         uhdr->ts_usec = pkth.ts.tv_usec;
 890
 891         /* parse endpoint information */
 892         if (pipeid1 == 'C')
 893                 urb_transfer = URB_CONTROL;
 894         else if (pipeid1 == 'Z')
 895                 urb_transfer = URB_ISOCHRONOUS;
 896         else if (pipeid1 == 'I')
 897                 urb_transfer = URB_INTERRUPT;
 898         else if (pipeid1 == 'B')
 899                 urb_transfer = URB_BULK;
 900         if (pipeid2 == 'i') {
 901                 ep_num |= URB_TRANSFER_IN;
 902                 incoming = 1;
 903         }
 904         if (etype == 'C')
 905                 incoming = !incoming;
 906
 907         /* direction check*/
 908         if (incoming)
 909         {
 910                 if (handle->direction == PCAP_D_OUT)
 911                         return 0;
 912         }
 913         else
 914                 if (handle->direction == PCAP_D_IN)
 915                         return 0;
 916         uhdr->event_type = etype;
 917         uhdr->transfer_type = urb_transfer;
 918         uhdr->endpoint_number = ep_num;
 919         pkth.caplen = sizeof(pcap_usb_header);
 920         rawdata += sizeof(pcap_usb_header);
 921
 922         /* check if this is a setup packet */
 923         ret = sscanf(status, "%d", &dummy);
 924         if (ret != 1)
 925         {
 926                 /* this a setup packet, setup data can be filled with underscore if
 927                 * usbmon has not been able to read them, so we must parse this fields as
 928                 * strings */
 929                 pcap_usb_setup* shdr;
 930                 char str1[3], str2[3], str3[5], str4[5], str5[5];
 931                 ret = sscanf(string, "%s %s %s %s %s%n", str1, str2, str3, str4,
 932                 str5, &cnt);
 933                 if (ret < 5)
 934                 {
 935                         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 936                                 "Can't parse USB bus message '%s', too few tokens (expected 5 got %d)",
 937                                 string, ret);
 938                         return -1;
 939                 }
 940                 string += cnt;
 941
 942                 /* try to convert to corresponding integer */
 943                 shdr = &uhdr->setup;
 944                 shdr->bmRequestType = strtoul(str1, 0, 16);
 945                 shdr->bRequest = strtoul(str2, 0, 16);
 946                 shdr->wValue = htols(strtoul(str3, 0, 16));
 947                 shdr->wIndex = htols(strtoul(str4, 0, 16));
 948                 shdr->wLength = htols(strtoul(str5, 0, 16));
 949
 950                 uhdr->setup_flag = 0;
 951         }
 952         else
 953                 uhdr->setup_flag = 1;
 954
 955         /* read urb data */
 956         ret = sscanf(string, " %d%n", &urb_len, &cnt);
 957         if (ret < 1)
 958         {
 959                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 960                   "Can't parse urb length from '%s'", string);
 961                 return -1;
 962         }
 963         string += cnt;
 964
 965         /* urb tag is not present if urb length is 0, so we can stop here
 966          * text parsing */
 967         pkth.len = urb_len+pkth.caplen;
 968         uhdr->urb_len = urb_len;
 969         uhdr->data_flag = 1;
 970         data_len = 0;
 971         if (uhdr->urb_len == 0)
 972                 goto got;
 973
 974         /* check for data presence; data is present if and only if urb tag is '=' */
 975         if (sscanf(string, " %c", &urb_tag) != 1)
 976         {
 977                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 978                         "Can't parse urb tag from '%s'", string);
 979                 return -1;
 980         }
 981
 982         if (urb_tag != '=')
 983                 goto got;
 984
 985         /* skip urb tag and following space */
 986         string += 3;
 987
 988         /* if we reach this point we got some urb data*/
 989         uhdr->data_flag = 0;
 990
 991         /* read all urb data; if urb length is greater then the usbmon internal
 992          * buffer length used by the kernel to spool the URB, we get only
 993          * a partial information.
 994          * At least until linux 2.6.17 there is no way to set usbmon intenal buffer
 995          * length and default value is 130. */
 996         while ((string[0] != 0) && (string[1] != 0) && (pkth.caplen < (bpf_u_int32)handle->snapshot))
 997         {
 998                 rawdata[0] = ascii_to_int(string[0]) * 16 + ascii_to_int(string[1]);
 999                 rawdata++;
1000                 string+=2;
1001                 if (string[0] == ' ')
1002                         string++;
1003                 pkth.caplen++;
1004                 data_len++;
1005         }
1006
1007 got:
1008         uhdr->data_len = data_len;
1009         if (pkth.caplen > (bpf_u_int32)handle->snapshot)
1010                 pkth.caplen = (bpf_u_int32)handle->snapshot;
1011
1012         if (handle->fcode.bf_insns == NULL ||
1013             bpf_filter(handle->fcode.bf_insns, handle->buffer,
1014               pkth.len, pkth.caplen)) {
1015                 handlep->packets_read++;
1016                 callback(user, &pkth, handle->buffer);
1017                 return 1;
1018         }
1019         return 0;       /* didn't pass filter */
1020 }
1021
1022 static int
1023 usb_inject_linux(pcap_t *handle, const void *buf _U_, size_t size _U_)
1024 {
1025         pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
1026             "Packet injection is not supported on USB devices");
1027         return (-1);
1028 }
1029
1030 static int
1031 usb_stats_linux(pcap_t *handle, struct pcap_stat *stats)
1032 {
1033         struct pcap_usb_linux *handlep = handle->priv;
1034         int dummy, ret, consumed, cnt;
1035         char string[USB_LINE_LEN];
1036         char token[USB_LINE_LEN];
1037         char * ptr = string;
1038         int fd;
1039
1040         pcap_snprintf(string, USB_LINE_LEN, USB_TEXT_DIR"/%ds", handlep->bus_index);
1041         fd = open(string, O_RDONLY, 0);
1042         if (fd < 0)
1043         {
1044                 if (errno == ENOENT)
1045                 {
1046                         /*
1047                          * Not found at the new location; try the old
1048                          * location.
1049                          */
1050                         pcap_snprintf(string, USB_LINE_LEN, USB_TEXT_DIR_OLD"/%ds", handlep->bus_index);
1051                         fd = open(string, O_RDONLY, 0);
1052                 }
1053                 if (fd < 0) {
1054                         pcap_fmt_errmsg_for_errno(handle->errbuf,
1055                             PCAP_ERRBUF_SIZE, errno,
1056                             "Can't open USB stats file %s", string);
1057                         return -1;
1058                 }
1059         }
1060
1061         /* read stats line */
1062         do {
1063                 ret = read(fd, string, USB_LINE_LEN-1);
1064         } while ((ret == -1) && (errno == EINTR));
1065         close(fd);
1066
1067         if (ret < 0)
1068         {
1069                 pcap_snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
1070                         "Can't read stats from fd %d ", fd);
1071                 return -1;
1072         }
1073         string[ret] = 0;
1074
1075         stats->ps_recv = handlep->packets_read;
1076         stats->ps_drop = 0;     /* unless we find text_lost */
1077         stats->ps_ifdrop = 0;
1078
1079         /* extract info on dropped urbs */
1080         for (consumed=0; consumed < ret; ) {
1081                 /* from the sscanf man page:
1082                  * The C standard says: "Execution of a %n directive does
1083                  * not increment the assignment count returned at the completion
1084                  * of  execution" but the Corrigendum seems to contradict this.
1085                  * Do not make any assumptions on the effect of %n conversions
1086                  * on the return value and explicitly check for cnt assignmet*/
1087                 int ntok;
1088
1089                 cnt = -1;
1090                 ntok = sscanf(ptr, "%s%n", token, &cnt);
1091                 if ((ntok < 1) || (cnt < 0))
1092                         break;
1093                 consumed += cnt;
1094                 ptr += cnt;
1095                 if (strcmp(token, "text_lost") == 0)
1096                         ntok = sscanf(ptr, "%d%n", &stats->ps_drop, &cnt);
1097                 else
1098                         ntok = sscanf(ptr, "%d%n", &dummy, &cnt);
1099                 if ((ntok != 1) || (cnt < 0))
1100                         break;
1101                 consumed += cnt;
1102                 ptr += cnt;
1103         }
1104
1105         return 0;
1106 }
1107
1108 static int
1109 usb_setdirection_linux(pcap_t *p, pcap_direction_t d)
1110 {
1111         p->direction = d;
1112         return 0;
1113 }
1114
1115
1116 static int
1117 usb_stats_linux_bin(pcap_t *handle, struct pcap_stat *stats)
1118 {
1119         struct pcap_usb_linux *handlep = handle->priv;
1120         int ret;
1121         struct mon_bin_stats st;
1122         ret = ioctl(handle->fd, MON_IOCG_STATS, &st);
1123         if (ret < 0)
1124         {
1125                 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
1126                     errno, "Can't read stats from fd %d", handle->fd);
1127                 return -1;
1128         }
1129
1130         stats->ps_recv = handlep->packets_read + st.queued;
1131         stats->ps_drop = st.dropped;
1132         stats->ps_ifdrop = 0;
1133         return 0;
1134 }
1135
1136 /*
1137  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
1138  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
1139  */
1140 static int
1141 usb_read_linux_bin(pcap_t *handle, int max_packets _U_, pcap_handler callback, u_char *user)
1142 {
1143         struct pcap_usb_linux *handlep = handle->priv;
1144         struct mon_bin_get info;
1145         int ret;
1146         struct pcap_pkthdr pkth;
1147         u_int clen = handle->snapshot - sizeof(pcap_usb_header);
1148
1149         /* the usb header is going to be part of 'packet' data*/
1150         info.hdr = (pcap_usb_header*) handle->buffer;
1151         info.data = (u_char *)handle->buffer + sizeof(pcap_usb_header);
1152         info.data_len = clen;
1153
1154         /* ignore interrupt system call errors */
1155         do {
1156                 ret = ioctl(handle->fd, MON_IOCX_GET, &info);
1157                 if (handle->break_loop)
1158                 {
1159                         handle->break_loop = 0;
1160                         return -2;
1161                 }
1162         } while ((ret == -1) && (errno == EINTR));
1163         if (ret < 0)
1164         {
1165                 if (errno == EAGAIN)
1166                         return 0;       /* no data there */
1167
1168                 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
1169                     errno, "Can't read from fd %d", handle->fd);
1170                 return -1;
1171         }
1172
1173         /*
1174          * info.hdr->data_len is the number of bytes of isochronous
1175          * descriptors (if any) plus the number of bytes of data
1176          * provided.  There are no isochronous descriptors here,
1177          * because we're using the old 48-byte header.
1178          *
1179          * If info.hdr->data_flag is non-zero, there's no URB data;
1180          * info.hdr->urb_len is the size of the buffer into which
1181          * data is to be placed; it does not represent the amount
1182          * of data transferred.  If info.hdr->data_flag is zero,
1183          * there is URB data, and info.hdr->urb_len is the number
1184          * of bytes transmitted or received; it doesn't include
1185          * isochronous descriptors.
1186          *
1187          * The kernel may give us more data than the snaplen; if it did,
1188          * reduce the data length so that the total number of bytes we
1189          * tell our client we have is not greater than the snaplen.
1190          */
1191         if (info.hdr->data_len < clen)
1192                 clen = info.hdr->data_len;
1193         info.hdr->data_len = clen;
1194         pkth.caplen = sizeof(pcap_usb_header) + clen;
1195         if (info.hdr->data_flag) {
1196                 /*
1197                  * No data; just base the on-the-wire length on
1198                  * info.hdr->data_len (so that it's >= the captured
1199                  * length).
1200                  */
1201                 pkth.len = sizeof(pcap_usb_header) + info.hdr->data_len;
1202         } else {
1203                 /*
1204                  * We got data; base the on-the-wire length on
1205                  * info.hdr->urb_len, so that it includes data
1206                  * discarded by the USB monitor device due to
1207                  * its buffer being too small.
1208                  */
1209                 pkth.len = sizeof(pcap_usb_header) + info.hdr->urb_len;
1210         }
1211         pkth.ts.tv_sec = info.hdr->ts_sec;
1212         pkth.ts.tv_usec = info.hdr->ts_usec;
1213
1214         if (handle->fcode.bf_insns == NULL ||
1215             bpf_filter(handle->fcode.bf_insns, handle->buffer,
1216               pkth.len, pkth.caplen)) {
1217                 handlep->packets_read++;
1218                 callback(user, &pkth, handle->buffer);
1219                 return 1;
1220         }
1221
1222         return 0;       /* didn't pass filter */
1223 }
1224
1225 /*
1226  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
1227  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
1228  */
1229 #define VEC_SIZE 32
1230 static int
1231 usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
1232 {
1233         struct pcap_usb_linux *handlep = handle->priv;
1234         struct mon_bin_mfetch fetch;
1235         int32_t vec[VEC_SIZE];
1236         struct pcap_pkthdr pkth;
1237         pcap_usb_header_mmapped* hdr;
1238         int nflush = 0;
1239         int packets = 0;
1240         u_int clen, max_clen;
1241
1242         max_clen = handle->snapshot - sizeof(pcap_usb_header_mmapped);
1243
1244         for (;;) {
1245                 int i, ret;
1246                 int limit = max_packets - packets;
1247                 if (limit <= 0)
1248                         limit = VEC_SIZE;
1249                 if (limit > VEC_SIZE)
1250                         limit = VEC_SIZE;
1251
1252                 /* try to fetch as many events as possible*/
1253                 fetch.offvec = vec;
1254                 fetch.nfetch = limit;
1255                 fetch.nflush = nflush;
1256                 /* ignore interrupt system call errors */
1257                 do {
1258                         ret = ioctl(handle->fd, MON_IOCX_MFETCH, &fetch);
1259                         if (handle->break_loop)
1260                         {
1261                                 handle->break_loop = 0;
1262                                 return -2;
1263                         }
1264                 } while ((ret == -1) && (errno == EINTR));
1265                 if (ret < 0)
1266                 {
1267                         if (errno == EAGAIN)
1268                                 return 0;       /* no data there */
1269
1270                         pcap_fmt_errmsg_for_errno(handle->errbuf,
1271                             PCAP_ERRBUF_SIZE, errno, "Can't mfetch fd %d",
1272                             handle->fd);
1273                         return -1;
1274                 }
1275
1276                 /* keep track of processed events, we will flush them later */
1277                 nflush = fetch.nfetch;
1278                 for (i=0; i<fetch.nfetch; ++i) {
1279                         /* discard filler */
1280                         hdr = (pcap_usb_header_mmapped*) &handlep->mmapbuf[vec[i]];
1281                         if (hdr->event_type == '@')
1282                                 continue;
1283
1284                         /*
1285                          * hdr->data_len is the number of bytes of
1286                          * isochronous descriptors (if any) plus the
1287                          * number of bytes of data provided.
1288                          *
1289                          * If hdr->data_flag is non-zero, there's no
1290                          * URB data; hdr->urb_len is the size of the
1291                          * buffer into which data is to be placed; it does
1292                          * not represent the amount of data transferred.
1293                          * If hdr->data_flag is zero, there is URB data,
1294                          * and hdr->urb_len is the number of bytes
1295                          * transmitted or received; it doesn't include
1296                          * isochronous descriptors.
1297                          *
1298                          * The kernel may give us more data than the
1299                          * snaplen; if it did, reduce the data length
1300                          * so that the total number of bytes we
1301                          * tell our client we have is not greater than
1302                          * the snaplen.
1303                          */
1304                         clen = max_clen;
1305                         if (hdr->data_len < clen)
1306                                 clen = hdr->data_len;
1307                         pkth.caplen = sizeof(pcap_usb_header_mmapped) + clen;
1308                         if (hdr->data_flag) {
1309                                 /*
1310                                  * No data; just base the on-the-wire length
1311                                  * on hdr->data_len (so that it's >= the
1312                                  * captured length).
1313                                  */
1314                                 pkth.len = sizeof(pcap_usb_header_mmapped) +
1315                                     hdr->data_len;
1316                         } else {
1317                                 /*
1318                                  * We got data; base the on-the-wire length
1319                                  * on hdr->urb_len, so that it includes
1320                                  * data discarded by the USB monitor device
1321                                  * due to its buffer being too small.
1322                                  */
1323                                 pkth.len = sizeof(pcap_usb_header_mmapped) +
1324                                     (hdr->ndesc * sizeof (usb_isodesc)) + hdr->urb_len;
1325                         }
1326                         pkth.ts.tv_sec = hdr->ts_sec;
1327                         pkth.ts.tv_usec = hdr->ts_usec;
1328
1329                         if (handle->fcode.bf_insns == NULL ||
1330                             bpf_filter(handle->fcode.bf_insns, (u_char*) hdr,
1331                               pkth.len, pkth.caplen)) {
1332                                 handlep->packets_read++;
1333                                 callback(user, &pkth, (u_char*) hdr);
1334                                 packets++;
1335                         }
1336                 }
1337
1338                 /* with max_packets specifying "unlimited" we stop afer the first chunk*/
1339                 if (PACKET_COUNT_IS_UNLIMITED(max_packets) || (packets == max_packets))
1340                         break;
1341         }
1342
1343         /* flush pending events*/
1344         if (ioctl(handle->fd, MON_IOCH_MFLUSH, nflush) == -1) {
1345                 pcap_fmt_errmsg_for_errno(handle->errbuf, PCAP_ERRBUF_SIZE,
1346                     errno, "Can't mflush fd %d", handle->fd);
1347                 return -1;
1348         }
1349         return packets;
1350 }
1351
1352 static void
1353 usb_cleanup_linux_mmap(pcap_t* handle)
1354 {
1355         struct pcap_usb_linux *handlep = handle->priv;
1356
1357         /* if we have a memory-mapped buffer, unmap it */
1358         if (handlep->mmapbuf != NULL) {
1359                 munmap(handlep->mmapbuf, handlep->mmapbuflen);
1360                 handlep->mmapbuf = NULL;
1361         }
1362         pcap_cleanup_live_common(handle);
1363 }