The Tcpdump Group git mirrors - libpcap/blob - 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 #ifndef lint
  36 static const char rcsid[] _U_ =
  37     "@(#) $Header: /tcpdump/master/libpcap/pcap-usb-linux.c,v 1.16.2.17 2008-12-23 21:39:03 guy Exp $ (LBL)";
  38 #endif
  39
  40 #ifdef HAVE_CONFIG_H
  41 #include "config.h"
  42 #endif
  43
  44 #include "pcap-int.h"
  45 #include "pcap-usb-linux.h"
  46 #include "pcap/usb.h"
  47
  48 #ifdef NEED_STRERROR_H
  49 #include "strerror.h"
  50 #endif
  51
  52 #include <ctype.h>
  53 #include <errno.h>
  54 #include <stdlib.h>
  55 #include <unistd.h>
  56 #include <fcntl.h>
  57 #include <string.h>
  58 #include <dirent.h>
  59 #include <byteswap.h>
  60 #include <netinet/in.h>
  61 #include <sys/ioctl.h>
  62 #include <sys/mman.h>
  63 #include <linux/usb/ch9.h>
  64 #ifdef HAVE_LINUX_USBDEVICE_FS_H
  65 #include <linux/usbdevice_fs.h>
  66 #endif
  67
  68 #define USB_IFACE "usb"
  69 #define USB_TEXT_DIR "/sys/kernel/debug/usbmon"
  70 #define SYS_USB_BUS_DIR "/sys/bus/usb/devices"
  71 #define PROC_USB_BUS_DIR "/proc/bus/usb"
  72 #define USB_LINE_LEN 4096
  73
  74 #if __BYTE_ORDER == __LITTLE_ENDIAN
  75 #define htols(s) s
  76 #define htoll(l) l
  77 #define htol64(ll) ll
  78 #else
  79 #define htols(s) bswap_16(s)
  80 #define htoll(l) bswap_32(l)
  81 #define htol64(ll) bswap_64(ll)
  82 #endif
  83
  84 struct mon_bin_stats {
  85         u_int32_t queued;
  86         u_int32_t dropped;
  87 };
  88
  89 struct mon_bin_get {
  90         pcap_usb_header *hdr;
  91         void *data;
  92         size_t data_len;   /* Length of data (can be zero) */
  93 };
  94
  95 struct mon_bin_mfetch {
  96         int32_t *offvec;   /* Vector of events fetched */
  97         int32_t nfetch;    /* Number of events to fetch (out: fetched) */
  98         int32_t nflush;    /* Number of events to flush */
  99 };
 100
 101 #define MON_IOC_MAGIC 0x92
 102
 103 #define MON_IOCQ_URB_LEN _IO(MON_IOC_MAGIC, 1)
 104 #define MON_IOCX_URB  _IOWR(MON_IOC_MAGIC, 2, struct mon_bin_hdr)
 105 #define MON_IOCG_STATS _IOR(MON_IOC_MAGIC, 3, struct mon_bin_stats)
 106 #define MON_IOCT_RING_SIZE _IO(MON_IOC_MAGIC, 4)
 107 #define MON_IOCQ_RING_SIZE _IO(MON_IOC_MAGIC, 5)
 108 #define MON_IOCX_GET   _IOW(MON_IOC_MAGIC, 6, struct mon_bin_get)
 109 #define MON_IOCX_MFETCH _IOWR(MON_IOC_MAGIC, 7, struct mon_bin_mfetch)
 110 #define MON_IOCH_MFLUSH _IO(MON_IOC_MAGIC, 8)
 111
 112 #define MON_BIN_SETUP   0x1 /* setup hdr is present*/
 113 #define MON_BIN_SETUP_ZERO      0x2 /* setup buffer is not available */
 114 #define MON_BIN_DATA_ZERO       0x4 /* data buffer is not available */
 115 #define MON_BIN_ERROR   0x8
 116
 117 /* forward declaration */
 118 static int usb_activate(pcap_t *);
 119 static int usb_stats_linux(pcap_t *, struct pcap_stat *);
 120 static int usb_stats_linux_bin(pcap_t *, struct pcap_stat *);
 121 static int usb_read_linux(pcap_t *, int , pcap_handler , u_char *);
 122 static int usb_read_linux_bin(pcap_t *, int , pcap_handler , u_char *);
 123 static int usb_read_linux_mmap(pcap_t *, int , pcap_handler , u_char *);
 124 static int usb_inject_linux(pcap_t *, const void *, size_t);
 125 static int usb_setfilter_linux(pcap_t *, struct bpf_program *);
 126 static int usb_setdirection_linux(pcap_t *, pcap_direction_t);
 127 static void usb_cleanup_linux_mmap(pcap_t *);
 128
 129 /* facility to add an USB device to the device list*/
 130 static int
 131 usb_dev_add(pcap_if_t** alldevsp, int n, char *err_str)
 132 {
 133         char dev_name[10];
 134         char dev_descr[30];
 135         snprintf(dev_name, 10, USB_IFACE"%d", n);
 136         snprintf(dev_descr, 30, "USB bus number %d", n);
 137
 138         if (pcap_add_if(alldevsp, dev_name, 0,
 139             dev_descr, err_str) < 0)
 140                 return -1;
 141         return 0;
 142 }
 143
 144 int
 145 usb_platform_finddevs(pcap_if_t **alldevsp, char *err_str)
 146 {
 147         struct dirent* data;
 148         int ret = 0;
 149         DIR* dir;
 150         int n;
 151         char* name;
 152         size_t len;
 153
 154         /* try scanning sysfs usb bus directory */
 155         dir = opendir(SYS_USB_BUS_DIR);
 156         if (dir != NULL) {
 157                 while ((ret == 0) && ((data = readdir(dir)) != 0)) {
 158                         name = data->d_name;
 159
 160                         if (strncmp(name, "usb", 3) != 0)
 161                                 continue;
 162
 163                         if (sscanf(&name[3], "%d", &n) == 0)
 164                                 continue;
 165
 166                         ret = usb_dev_add(alldevsp, n, err_str);
 167                 }
 168
 169                 closedir(dir);
 170                 return ret;
 171         }
 172
 173         /* that didn't work; try scanning procfs usb bus directory */
 174         dir = opendir(PROC_USB_BUS_DIR);
 175         if (dir != NULL) {
 176                 while ((ret == 0) && ((data = readdir(dir)) != 0)) {
 177                         name = data->d_name;
 178                         len = strlen(name);
 179
 180                         /* if this file name does not end with a number it's not of our interest */
 181                         if ((len < 1) || !isdigit(name[--len]))
 182                                 continue;
 183                         while (isdigit(name[--len]));
 184                         if (sscanf(&name[len+1], "%d", &n) != 1)
 185                                 continue;
 186
 187                         ret = usb_dev_add(alldevsp, n, err_str);
 188                 }
 189
 190                 closedir(dir);
 191                 return ret;
 192         }
 193
 194         /* neither of them worked */
 195         return 0;
 196 }
 197
 198 static
 199 int usb_mmap(pcap_t* handle)
 200 {
 201         int len = ioctl(handle->fd, MON_IOCQ_RING_SIZE);
 202         if (len < 0)
 203                 return 0;
 204
 205         handle->buffer = mmap(0, len, PROT_READ, MAP_SHARED, handle->fd, 0);
 206         return handle->buffer != MAP_FAILED;
 207 }
 208
 209 #define CTRL_TIMEOUT    (5*1000)        /* milliseconds */
 210
 211 /* probe the descriptors of the devices attached to the bus */
 212 /* the descriptors will end up in the captured packet stream */
 213 /* and be decoded by external apps like wireshark */
 214 /* without these identifying probes packet data can't be fully decoded */
 215 static void
 216 probe_devices(int bus)
 217 {
 218         struct usbdevfs_ctrltransfer ctrl;
 219         struct usb_device_descriptor device;
 220         struct dirent* data;
 221         int ret = 0;
 222         char buf[40];
 223         DIR* dir;
 224
 225         /* scan usb bus directories for device nodes */
 226         snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d", bus);
 227         dir = opendir(buf);
 228         if (!dir)
 229                 return;
 230
 231         while ((ret >= 0) && ((data = readdir(dir)) != 0)) {
 232                 int fd;
 233                 char* name = data->d_name;
 234
 235                 if (name[0] == '.')
 236                         continue;
 237
 238                 snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d/%s", bus, data->d_name);
 239
 240                 fd = open(buf, O_RDWR);
 241                 if (fd == -1)
 242                         continue;
 243
 244                 ctrl.bRequestType = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
 245                 ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
 246                 ctrl.wValue = USB_DT_DEVICE << 8;
 247                 ctrl.wIndex = 0;
 248                 ctrl.wLength = sizeof(device);
 249                 ctrl.data = &device;
 250                 ctrl.timeout = CTRL_TIMEOUT;
 251
 252                 ret = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
 253
 254                 close(fd);
 255         }
 256         closedir(dir);
 257 }
 258
 259 pcap_t *
 260 usb_create(const char *device, char *ebuf)
 261 {
 262         pcap_t *p;
 263
 264         p = pcap_create_common(device, ebuf);
 265         if (p == NULL)
 266                 return (NULL);
 267
 268         p->activate_op = usb_activate;
 269         return (p);
 270 }
 271
 272 static int
 273 usb_activate(pcap_t* handle)
 274 {
 275         char            full_path[USB_LINE_LEN];
 276
 277         /* Initialize some components of the pcap structure. */
 278         handle->bufsize = handle->snapshot;
 279         handle->offset = 0;
 280         handle->linktype = DLT_USB_LINUX;
 281
 282         handle->inject_op = usb_inject_linux;
 283         handle->setfilter_op = usb_setfilter_linux;
 284         handle->setdirection_op = usb_setdirection_linux;
 285         handle->set_datalink_op = NULL; /* can't change data link type */
 286         handle->getnonblock_op = pcap_getnonblock_fd;
 287         handle->setnonblock_op = pcap_setnonblock_fd;
 288
 289         /*get usb bus index from device name */
 290         if (sscanf(handle->opt.source, USB_IFACE"%d", &handle->md.ifindex) != 1)
 291         {
 292                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 293                         "Can't get USB bus index from %s", handle->opt.source);
 294                 return PCAP_ERROR;
 295         }
 296
 297         /*now select the read method: try to open binary interface */
 298         snprintf(full_path, USB_LINE_LEN, LINUX_USB_MON_DEV"%d", handle->md.ifindex);
 299         handle->fd = open(full_path, O_RDONLY, 0);
 300         if (handle->fd >= 0)
 301         {
 302                 if (handle->opt.rfmon) {
 303                         /*
 304                          * Monitor mode doesn't apply to USB devices.
 305                          */
 306                         close(handle->fd);
 307                         return PCAP_ERROR_RFMON_NOTSUP;
 308                 }
 309
 310                 /* binary api is available, try to use fast mmap access */
 311                 if (usb_mmap(handle)) {
 312                         handle->linktype = DLT_USB_LINUX_MMAPPED;
 313                         handle->stats_op = usb_stats_linux_bin;
 314                         handle->read_op = usb_read_linux_mmap;
 315                         handle->cleanup_op = usb_cleanup_linux_mmap;
 316                         probe_devices(handle->md.ifindex);
 317
 318                         /*
 319                          * "handle->fd" is a real file, so "select()" and
 320                          * "poll()" work on it.
 321                          */
 322                         handle->selectable_fd = handle->fd;
 323                         return 0;
 324                 }
 325
 326                 /* can't mmap, use plain binary interface access */
 327                 handle->stats_op = usb_stats_linux_bin;
 328                 handle->read_op = usb_read_linux_bin;
 329                 probe_devices(handle->md.ifindex);
 330         }
 331         else {
 332                 /*Binary interface not available, try open text interface */
 333                 snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR"/%dt", handle->md.ifindex);
 334                 handle->fd = open(full_path, O_RDONLY, 0);
 335                 if (handle->fd < 0)
 336                 {
 337                         /* no more fallback, give it up*/
 338                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 339                                 "Can't open USB bus file %s: %s", full_path, strerror(errno));
 340                         return PCAP_ERROR;
 341                 }
 342
 343                 if (handle->opt.rfmon) {
 344                         /*
 345                          * Monitor mode doesn't apply to USB devices.
 346                          */
 347                         close(handle->fd);
 348                         return PCAP_ERROR_RFMON_NOTSUP;
 349                 }
 350
 351                 handle->stats_op = usb_stats_linux;
 352                 handle->read_op = usb_read_linux;
 353         }
 354
 355         /*
 356          * "handle->fd" is a real file, so "select()" and "poll()"
 357          * work on it.
 358          */
 359         handle->selectable_fd = handle->fd;
 360
 361         /* for plain binary access and text access we need to allocate the read
 362          * buffer */
 363         handle->buffer = malloc(handle->bufsize);
 364         if (!handle->buffer) {
 365                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 366                          "malloc: %s", pcap_strerror(errno));
 367                 return PCAP_ERROR;
 368         }
 369         return 0;
 370 }
 371
 372 static inline int
 373 ascii_to_int(char c)
 374 {
 375         return c < 'A' ? c- '0': ((c<'a') ? c - 'A' + 10: c-'a'+10);
 376 }
 377
 378 /*
 379  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 380  * <linux-kernel-source>/drivers/usb/mon/mon_text.c for urb string
 381  * format description
 382  */
 383 static int
 384 usb_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 385 {
 386         /* see:
 387         * /usr/src/linux/Documentation/usb/usbmon.txt
 388         * for message format
 389         */
 390         unsigned timestamp;
 391         int tag, cnt, ep_num, dev_addr, dummy, ret, urb_len, data_len;
 392         char etype, pipeid1, pipeid2, status[16], urb_tag, line[USB_LINE_LEN];
 393         char *string = line;
 394         u_char * rawdata = handle->buffer;
 395         struct pcap_pkthdr pkth;
 396         pcap_usb_header* uhdr = (pcap_usb_header*)handle->buffer;
 397         u_char urb_transfer=0;
 398         int incoming=0;
 399
 400         /* ignore interrupt system call errors */
 401         do {
 402                 ret = read(handle->fd, line, USB_LINE_LEN - 1);
 403                 if (handle->break_loop)
 404                 {
 405                         handle->break_loop = 0;
 406                         return -2;
 407                 }
 408         } while ((ret == -1) && (errno == EINTR));
 409         if (ret < 0)
 410         {
 411                 if (errno == EAGAIN)
 412                         return 0;       /* no data there */
 413
 414                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 415                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 416                 return -1;
 417         }
 418
 419         /* read urb header; %n argument may increment return value, but it's
 420         * not mandatory, so does not count on it*/
 421         string[ret] = 0;
 422         ret = sscanf(string, "%x %d %c %c%c:%d:%d %s%n", &tag, &timestamp, &etype,
 423                 &pipeid1, &pipeid2, &dev_addr, &ep_num, status,
 424                 &cnt);
 425         if (ret < 8)
 426         {
 427                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 428                     "Can't parse USB bus message '%s', too few tokens (expected 8 got %d)",
 429                     string, ret);
 430                 return -1;
 431         }
 432         uhdr->id = tag;
 433         uhdr->device_address = dev_addr;
 434         uhdr->bus_id = handle->md.ifindex;
 435         uhdr->status = 0;
 436         string += cnt;
 437
 438         /* don't use usbmon provided timestamp, since it have low precision*/
 439         if (gettimeofday(&pkth.ts, NULL) < 0)
 440         {
 441                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 442                         "Can't get timestamp for message '%s' %d:%s",
 443                         string, errno, strerror(errno));
 444                 return -1;
 445         }
 446         uhdr->ts_sec = pkth.ts.tv_sec;
 447         uhdr->ts_usec = pkth.ts.tv_usec;
 448
 449         /* parse endpoint information */
 450         if (pipeid1 == 'C')
 451                 urb_transfer = URB_CONTROL;
 452         else if (pipeid1 == 'Z')
 453                 urb_transfer = URB_ISOCHRONOUS;
 454         else if (pipeid1 == 'I')
 455                 urb_transfer = URB_INTERRUPT;
 456         else if (pipeid1 == 'B')
 457                 urb_transfer = URB_BULK;
 458         if (pipeid2 == 'i') {
 459                 ep_num |= URB_TRANSFER_IN;
 460                 incoming = 1;
 461         }
 462         if (etype == 'C')
 463                 incoming = !incoming;
 464
 465         /* direction check*/
 466         if (incoming)
 467         {
 468                 if (handle->direction == PCAP_D_OUT)
 469                         return 0;
 470         }
 471         else
 472                 if (handle->direction == PCAP_D_IN)
 473                         return 0;
 474         uhdr->event_type = etype;
 475         uhdr->transfer_type = urb_transfer;
 476         uhdr->endpoint_number = ep_num;
 477         pkth.caplen = sizeof(pcap_usb_header);
 478         rawdata += sizeof(pcap_usb_header);
 479
 480         /* check if this is a setup packet */
 481         ret = sscanf(status, "%d", &dummy);
 482         if (ret != 1)
 483         {
 484                 /* this a setup packet, setup data can be filled with underscore if
 485                 * usbmon has not been able to read them, so we must parse this fields as
 486                 * strings */
 487                 pcap_usb_setup* shdr;
 488                 char str1[3], str2[3], str3[5], str4[5], str5[5];
 489                 ret = sscanf(string, "%s %s %s %s %s%n", str1, str2, str3, str4,
 490                 str5, &cnt);
 491                 if (ret < 5)
 492                 {
 493                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 494                                 "Can't parse USB bus message '%s', too few tokens (expected 5 got %d)",
 495                                 string, ret);
 496                         return -1;
 497                 }
 498                 string += cnt;
 499
 500                 /* try to convert to corresponding integer */
 501                 shdr = &uhdr->setup;
 502                 shdr->bmRequestType = strtoul(str1, 0, 16);
 503                 shdr->bRequest = strtoul(str2, 0, 16);
 504                 shdr->wValue = htols(strtoul(str3, 0, 16));
 505                 shdr->wIndex = htols(strtoul(str4, 0, 16));
 506                 shdr->wLength = htols(strtoul(str5, 0, 16));
 507
 508                 uhdr->setup_flag = 0;
 509         }
 510         else
 511                 uhdr->setup_flag = 1;
 512
 513         /* read urb data */
 514         ret = sscanf(string, " %d%n", &urb_len, &cnt);
 515         if (ret < 1)
 516         {
 517                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 518                   "Can't parse urb length from '%s'", string);
 519                 return -1;
 520         }
 521         string += cnt;
 522
 523         /* urb tag is not present if urb length is 0, so we can stop here
 524          * text parsing */
 525         pkth.len = urb_len+pkth.caplen;
 526         uhdr->urb_len = urb_len;
 527         uhdr->data_flag = 1;
 528         data_len = 0;
 529         if (uhdr->urb_len == 0)
 530                 goto got;
 531
 532         /* check for data presence; data is present if and only if urb tag is '=' */
 533         if (sscanf(string, " %c", &urb_tag) != 1)
 534         {
 535                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 536                         "Can't parse urb tag from '%s'", string);
 537                 return -1;
 538         }
 539
 540         if (urb_tag != '=')
 541                 goto got;
 542
 543         /* skip urb tag and following space */
 544         string += 3;
 545
 546         /* if we reach this point we got some urb data*/
 547         uhdr->data_flag = 0;
 548
 549         /* read all urb data; if urb length is greater then the usbmon internal
 550          * buffer length used by the kernel to spool the URB, we get only
 551          * a partial information.
 552          * At least until linux 2.6.17 there is no way to set usbmon intenal buffer
 553          * length and default value is 130. */
 554         while ((string[0] != 0) && (string[1] != 0) && (pkth.caplen < handle->snapshot))
 555         {
 556                 rawdata[0] = ascii_to_int(string[0]) * 16 + ascii_to_int(string[1]);
 557                 rawdata++;
 558                 string+=2;
 559                 if (string[0] == ' ')
 560                         string++;
 561                 pkth.caplen++;
 562                 data_len++;
 563         }
 564
 565 got:
 566         uhdr->data_len = data_len;
 567         handle->md.packets_read++;
 568         if (pkth.caplen > handle->snapshot)
 569                 pkth.caplen = handle->snapshot;
 570
 571         callback(user, &pkth, handle->buffer);
 572         return 1;
 573 }
 574
 575 static int
 576 usb_inject_linux(pcap_t *handle, const void *buf, size_t size)
 577 {
 578         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
 579                 "USB devices");
 580         return (-1);
 581 }
 582
 583 static int
 584 usb_stats_linux(pcap_t *handle, struct pcap_stat *stats)
 585 {
 586         int dummy, ret, consumed, cnt;
 587         char string[USB_LINE_LEN];
 588         char token[USB_LINE_LEN];
 589         char * ptr = string;
 590         snprintf(string, USB_LINE_LEN, USB_TEXT_DIR"/%ds", handle->md.ifindex);
 591
 592         int fd = open(string, O_RDONLY, 0);
 593         if (fd < 0)
 594         {
 595                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 596                         "Can't open USB stats file %s: %s",
 597                         string, strerror(errno));
 598                 return -1;
 599         }
 600
 601         /* read stats line */
 602         do {
 603                 ret = read(fd, string, USB_LINE_LEN-1);
 604         } while ((ret == -1) && (errno == EINTR));
 605         close(fd);
 606
 607         if (ret < 0)
 608         {
 609                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 610                         "Can't read stats from fd %d ", fd);
 611                 return -1;
 612         }
 613         string[ret] = 0;
 614
 615         /* extract info on dropped urbs */
 616         for (consumed=0; consumed < ret; ) {
 617                 /* from the sscanf man page:
 618                  * The C standard says: "Execution of a %n directive does
 619                  * not increment the assignment count returned at the completion
 620                  * of  execution" but the Corrigendum seems to contradict this.
 621                  * Do not make any assumptions on the effect of %n conversions
 622                  * on the return value and explicitly check for cnt assignmet*/
 623                 cnt = -1;
 624                 int ntok = sscanf(ptr, "%s%n", token, &cnt);
 625                 if ((ntok < 1) || (cnt < 0))
 626                         break;
 627                 consumed += cnt;
 628                 ptr += cnt;
 629                 if (strcmp(token, "nreaders") == 0)
 630                         ret = sscanf(ptr, "%d", &stats->ps_drop);
 631                 else
 632                         ret = sscanf(ptr, "%d", &dummy);
 633                 if (ntok != 1)
 634                         break;
 635                 consumed += cnt;
 636                 ptr += cnt;
 637         }
 638
 639         stats->ps_recv = handle->md.packets_read;
 640         stats->ps_ifdrop = 0;
 641         return 0;
 642 }
 643
 644 static int
 645 usb_setfilter_linux(pcap_t *p, struct bpf_program *fp)
 646 {
 647         return 0;
 648 }
 649
 650 static int
 651 usb_setdirection_linux(pcap_t *p, pcap_direction_t d)
 652 {
 653         p->direction = d;
 654         return 0;
 655 }
 656
 657
 658 static int
 659 usb_stats_linux_bin(pcap_t *handle, struct pcap_stat *stats)
 660 {
 661         int ret;
 662         struct mon_bin_stats st;
 663         ret = ioctl(handle->fd, MON_IOCG_STATS, &st);
 664         if (ret < 0)
 665         {
 666                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 667                         "Can't read stats from fd %d:%s ", handle->fd, strerror(errno));
 668                 return -1;
 669         }
 670
 671         stats->ps_recv = handle->md.packets_read + st.queued;
 672         stats->ps_ifdrop = 0;
 673         stats->ps_drop = st.dropped;
 674         return 0;
 675 }
 676
 677 /*
 678  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 679  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 680  */
 681 static int
 682 usb_read_linux_bin(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 683 {
 684         struct mon_bin_get info;
 685         int ret;
 686         struct pcap_pkthdr pkth;
 687         int clen = handle->snapshot - sizeof(pcap_usb_header);
 688
 689         /* the usb header is going to be part of 'packet' data*/
 690         info.hdr = (pcap_usb_header*) handle->buffer;
 691         info.data = handle->buffer + sizeof(pcap_usb_header);
 692         info.data_len = clen;
 693
 694         /* ignore interrupt system call errors */
 695         do {
 696                 ret = ioctl(handle->fd, MON_IOCX_GET, &info);
 697                 if (handle->break_loop)
 698                 {
 699                         handle->break_loop = 0;
 700                         return -2;
 701                 }
 702         } while ((ret == -1) && (errno == EINTR));
 703         if (ret < 0)
 704         {
 705                 if (errno == EAGAIN)
 706                         return 0;       /* no data there */
 707
 708                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 709                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 710                 return -1;
 711         }
 712
 713         /* we can get less that than really captured from kernel, depending on
 714          * snaplen, so adjust header accordingly */
 715         if (info.hdr->data_len < clen)
 716                 clen = info.hdr->data_len;
 717         info.hdr->data_len = clen;
 718         pkth.caplen = clen + sizeof(pcap_usb_header);
 719         pkth.len = info.hdr->data_len + sizeof(pcap_usb_header);
 720         pkth.ts.tv_sec = info.hdr->ts_sec;
 721         pkth.ts.tv_usec = info.hdr->ts_usec;
 722
 723         handle->md.packets_read++;
 724         callback(user, &pkth, handle->buffer);
 725         return 1;
 726 }
 727
 728 /*
 729  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 730  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 731  */
 732 #define VEC_SIZE 32
 733 static int
 734 usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 735 {
 736         struct mon_bin_mfetch fetch;
 737         int32_t vec[VEC_SIZE];
 738         struct pcap_pkthdr pkth;
 739         pcap_usb_header* hdr;
 740         int nflush = 0;
 741         int packets = 0;
 742         int clen, max_clen;
 743
 744         max_clen = handle->snapshot - sizeof(pcap_usb_header);
 745
 746         for (;;) {
 747                 int i, ret;
 748                 int limit = max_packets - packets;
 749                 if (limit <= 0)
 750                         limit = VEC_SIZE;
 751                 if (limit > VEC_SIZE)
 752                         limit = VEC_SIZE;
 753
 754                 /* try to fetch as many events as possible*/
 755                 fetch.offvec = vec;
 756                 fetch.nfetch = limit;
 757                 fetch.nflush = nflush;
 758                 /* ignore interrupt system call errors */
 759                 do {
 760                         ret = ioctl(handle->fd, MON_IOCX_MFETCH, &fetch);
 761                         if (handle->break_loop)
 762                         {
 763                                 handle->break_loop = 0;
 764                                 return -2;
 765                         }
 766                 } while ((ret == -1) && (errno == EINTR));
 767                 if (ret < 0)
 768                 {
 769                         if (errno == EAGAIN)
 770                                 return 0;       /* no data there */
 771
 772                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 773                             "Can't mfetch fd %d: %s", handle->fd, strerror(errno));
 774                         return -1;
 775                 }
 776
 777                 /* keep track of processed events, we will flush them later */
 778                 nflush = fetch.nfetch;
 779                 for (i=0; i<fetch.nfetch; ++i) {
 780                         /* discard filler */
 781                         hdr = (pcap_usb_header*) &handle->buffer[vec[i]];
 782                         if (hdr->event_type == '@')
 783                                 continue;
 784
 785                         /* we can get less that than really captured from kernel, depending on
 786                         * snaplen, so adjust header accordingly */
 787                         clen = max_clen;
 788                         if (hdr->data_len < clen)
 789                                 clen = hdr->data_len;
 790
 791                         /* get packet info from header*/
 792                         pkth.caplen = clen + sizeof(pcap_usb_header_mmapped);
 793                         pkth.len = hdr->data_len + sizeof(pcap_usb_header_mmapped);
 794                         pkth.ts.tv_sec = hdr->ts_sec;
 795                         pkth.ts.tv_usec = hdr->ts_usec;
 796
 797                         handle->md.packets_read++;
 798                         callback(user, &pkth, (u_char*) hdr);
 799                         packets++;
 800                 }
 801
 802                 /* with max_packets <= 0 we stop afer the first chunk*/
 803                 if ((max_packets <= 0) || (packets == max_packets))
 804                         break;
 805         }
 806
 807         /* flush pending events*/
 808         ioctl(handle->fd, MON_IOCH_MFLUSH, nflush);
 809         return packets;
 810 }
 811
 812 static void
 813 usb_cleanup_linux_mmap(pcap_t* handle)
 814 {
 815         /* buffer must not be freed because it's memory mapped */
 816         /* XXX - does it need to be unmapped? */
 817         handle->buffer = NULL;
 818         pcap_cleanup_live_common(handle);
 819 }