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 1.33 2008-12-23 21:38:50 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 #ifdef HAVE_LINUX_USBDEVICE_FS_H
  64 #include <linux/usbdevice_fs.h>
  65 #endif
  66
  67 #define USB_IFACE "usbmon"
  68 #define USB_TEXT_DIR "/sys/kernel/debug/usbmon"
  69 #define SYS_USB_BUS_DIR "/sys/bus/usb/devices"
  70 #define PROC_USB_BUS_DIR "/proc/bus/usb"
  71 #define USB_LINE_LEN 4096
  72
  73 #if __BYTE_ORDER == __LITTLE_ENDIAN
  74 #define htols(s) s
  75 #define htoll(l) l
  76 #define htol64(ll) ll
  77 #else
  78 #define htols(s) bswap_16(s)
  79 #define htoll(l) bswap_32(l)
  80 #define htol64(ll) bswap_64(ll)
  81 #endif
  82
  83 struct mon_bin_stats {
  84         u_int32_t queued;
  85         u_int32_t dropped;
  86 };
  87
  88 struct mon_bin_get {
  89         pcap_usb_header *hdr;
  90         void *data;
  91         size_t data_len;   /* Length of data (can be zero) */
  92 };
  93
  94 struct mon_bin_mfetch {
  95         int32_t *offvec;   /* Vector of events fetched */
  96         int32_t nfetch;    /* Number of events to fetch (out: fetched) */
  97         int32_t nflush;    /* Number of events to flush */
  98 };
  99
 100 #define MON_IOC_MAGIC 0x92
 101
 102 #define MON_IOCQ_URB_LEN _IO(MON_IOC_MAGIC, 1)
 103 #define MON_IOCX_URB  _IOWR(MON_IOC_MAGIC, 2, struct mon_bin_hdr)
 104 #define MON_IOCG_STATS _IOR(MON_IOC_MAGIC, 3, struct mon_bin_stats)
 105 #define MON_IOCT_RING_SIZE _IO(MON_IOC_MAGIC, 4)
 106 #define MON_IOCQ_RING_SIZE _IO(MON_IOC_MAGIC, 5)
 107 #define MON_IOCX_GET   _IOW(MON_IOC_MAGIC, 6, struct mon_bin_get)
 108 #define MON_IOCX_MFETCH _IOWR(MON_IOC_MAGIC, 7, struct mon_bin_mfetch)
 109 #define MON_IOCH_MFLUSH _IO(MON_IOC_MAGIC, 8)
 110
 111 #define MON_BIN_SETUP   0x1 /* setup hdr is present*/
 112 #define MON_BIN_SETUP_ZERO      0x2 /* setup buffer is not available */
 113 #define MON_BIN_DATA_ZERO       0x4 /* data buffer is not available */
 114 #define MON_BIN_ERROR   0x8
 115
 116 /* forward declaration */
 117 static int usb_activate(pcap_t *);
 118 static int usb_stats_linux(pcap_t *, struct pcap_stat *);
 119 static int usb_stats_linux_bin(pcap_t *, struct pcap_stat *);
 120 static int usb_read_linux(pcap_t *, int , pcap_handler , u_char *);
 121 static int usb_read_linux_bin(pcap_t *, int , pcap_handler , u_char *);
 122 static int usb_read_linux_mmap(pcap_t *, int , pcap_handler , u_char *);
 123 static int usb_inject_linux(pcap_t *, const void *, size_t);
 124 static int usb_setfilter_linux(pcap_t *, struct bpf_program *);
 125 static int usb_setdirection_linux(pcap_t *, pcap_direction_t);
 126 static void usb_cleanup_linux_mmap(pcap_t *);
 127
 128 /* facility to add an USB device to the device list*/
 129 static int
 130 usb_dev_add(pcap_if_t** alldevsp, int n, char *err_str)
 131 {
 132         char dev_name[10];
 133         char dev_descr[30];
 134         snprintf(dev_name, 10, USB_IFACE"%d", n);
 135         snprintf(dev_descr, 30, "USB bus number %d", n);
 136
 137         if (pcap_add_if(alldevsp, dev_name, 0,
 138             dev_descr, err_str) < 0)
 139                 return -1;
 140         return 0;
 141 }
 142
 143 int
 144 usb_platform_finddevs(pcap_if_t **alldevsp, char *err_str)
 145 {
 146         struct dirent* data;
 147         int ret = 0;
 148         DIR* dir;
 149         int n;
 150         char* name;
 151         size_t len;
 152
 153         /* try scanning sysfs usb bus directory */
 154         dir = opendir(SYS_USB_BUS_DIR);
 155         if (dir != NULL) {
 156                 while ((ret == 0) && ((data = readdir(dir)) != 0)) {
 157                         name = data->d_name;
 158
 159                         if (strncmp(name, "usb", 3) != 0)
 160                                 continue;
 161
 162                         if (sscanf(&name[3], "%d", &n) == 0)
 163                                 continue;
 164
 165                         ret = usb_dev_add(alldevsp, n, err_str);
 166                 }
 167
 168                 closedir(dir);
 169                 return ret;
 170         }
 171
 172         /* that didn't work; try scanning procfs usb bus directory */
 173         dir = opendir(PROC_USB_BUS_DIR);
 174         if (dir != NULL) {
 175                 while ((ret == 0) && ((data = readdir(dir)) != 0)) {
 176                         name = data->d_name;
 177                         len = strlen(name);
 178
 179                         /* if this file name does not end with a number it's not of our interest */
 180                         if ((len < 1) || !isdigit(name[--len]))
 181                                 continue;
 182                         while (isdigit(name[--len]));
 183                         if (sscanf(&name[len+1], "%d", &n) != 1)
 184                                 continue;
 185
 186                         ret = usb_dev_add(alldevsp, n, err_str);
 187                 }
 188
 189                 closedir(dir);
 190                 return ret;
 191         }
 192
 193         /* neither of them worked */
 194         return 0;
 195 }
 196
 197 static
 198 int usb_mmap(pcap_t* handle)
 199 {
 200         int len = ioctl(handle->fd, MON_IOCQ_RING_SIZE);
 201         if (len < 0)
 202                 return 0;
 203
 204         handle->buffer = mmap(0, len, PROT_READ, MAP_SHARED, handle->fd, 0);
 205         return handle->buffer != MAP_FAILED;
 206 }
 207
 208 #define CTRL_TIMEOUT    (5*1000)        /* milliseconds */
 209
 210 #define USB_DIR_IN              0x80
 211 #define USB_TYPE_STANDARD       0x00
 212 #define USB_RECIP_DEVICE        0x00
 213
 214 #define USB_REQ_GET_DESCRIPTOR  6
 215
 216 #define USB_DT_DEVICE           1
 217
 218 /* probe the descriptors of the devices attached to the bus */
 219 /* the descriptors will end up in the captured packet stream */
 220 /* and be decoded by external apps like wireshark */
 221 /* without these identifying probes packet data can't be fully decoded */
 222 static void
 223 probe_devices(int bus)
 224 {
 225         struct usbdevfs_ctrltransfer ctrl;
 226         struct dirent* data;
 227         int ret = 0;
 228         char buf[40];
 229         DIR* dir;
 230
 231         /* scan usb bus directories for device nodes */
 232         snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d", bus);
 233         dir = opendir(buf);
 234         if (!dir)
 235                 return;
 236
 237         while ((ret >= 0) && ((data = readdir(dir)) != 0)) {
 238                 int fd;
 239                 char* name = data->d_name;
 240
 241                 if (name[0] == '.')
 242                         continue;
 243
 244                 snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d/%s", bus, data->d_name);
 245
 246                 fd = open(buf, O_RDWR);
 247                 if (fd == -1)
 248                         continue;
 249
 250                 ctrl.bRequestType = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
 251                 ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
 252                 ctrl.wValue = USB_DT_DEVICE << 8;
 253                 ctrl.wIndex = 0;
 254                 ctrl.wLength = sizeof(buf);
 255                 ctrl.data = buf;
 256                 ctrl.timeout = CTRL_TIMEOUT;
 257
 258                 ret = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
 259
 260                 close(fd);
 261         }
 262         closedir(dir);
 263 }
 264
 265 pcap_t *
 266 usb_create(const char *device, char *ebuf)
 267 {
 268         pcap_t *p;
 269
 270         p = pcap_create_common(device, ebuf);
 271         if (p == NULL)
 272                 return (NULL);
 273
 274         p->activate_op = usb_activate;
 275         return (p);
 276 }
 277
 278 static int
 279 usb_activate(pcap_t* handle)
 280 {
 281         char            full_path[USB_LINE_LEN];
 282
 283         /* Initialize some components of the pcap structure. */
 284         handle->bufsize = handle->snapshot;
 285         handle->offset = 0;
 286         handle->linktype = DLT_USB_LINUX;
 287
 288         handle->inject_op = usb_inject_linux;
 289         handle->setfilter_op = usb_setfilter_linux;
 290         handle->setdirection_op = usb_setdirection_linux;
 291         handle->set_datalink_op = NULL; /* can't change data link type */
 292         handle->getnonblock_op = pcap_getnonblock_fd;
 293         handle->setnonblock_op = pcap_setnonblock_fd;
 294
 295         /*get usb bus index from device name */
 296         if (sscanf(handle->opt.source, USB_IFACE"%d", &handle->md.ifindex) != 1)
 297         {
 298                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 299                         "Can't get USB bus index from %s", handle->opt.source);
 300                 return PCAP_ERROR;
 301         }
 302
 303         /*now select the read method: try to open binary interface */
 304         snprintf(full_path, USB_LINE_LEN, LINUX_USB_MON_DEV"%d", handle->md.ifindex);
 305         handle->fd = open(full_path, O_RDONLY, 0);
 306         if (handle->fd >= 0)
 307         {
 308                 if (handle->opt.rfmon) {
 309                         /*
 310                          * Monitor mode doesn't apply to USB devices.
 311                          */
 312                         close(handle->fd);
 313                         return PCAP_ERROR_RFMON_NOTSUP;
 314                 }
 315
 316                 /* binary api is available, try to use fast mmap access */
 317                 if (usb_mmap(handle)) {
 318                         handle->linktype = DLT_USB_LINUX_MMAPPED;
 319                         handle->stats_op = usb_stats_linux_bin;
 320                         handle->read_op = usb_read_linux_mmap;
 321                         handle->cleanup_op = usb_cleanup_linux_mmap;
 322                         probe_devices(handle->md.ifindex);
 323
 324                         /*
 325                          * "handle->fd" is a real file, so "select()" and
 326                          * "poll()" work on it.
 327                          */
 328                         handle->selectable_fd = handle->fd;
 329                         return 0;
 330                 }
 331
 332                 /* can't mmap, use plain binary interface access */
 333                 handle->stats_op = usb_stats_linux_bin;
 334                 handle->read_op = usb_read_linux_bin;
 335                 probe_devices(handle->md.ifindex);
 336         }
 337         else {
 338                 /*Binary interface not available, try open text interface */
 339                 snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR"/%dt", handle->md.ifindex);
 340                 handle->fd = open(full_path, O_RDONLY, 0);
 341                 if (handle->fd < 0)
 342                 {
 343                         /* no more fallback, give it up*/
 344                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 345                                 "Can't open USB bus file %s: %s", full_path, strerror(errno));
 346                         return PCAP_ERROR;
 347                 }
 348
 349                 if (handle->opt.rfmon) {
 350                         /*
 351                          * Monitor mode doesn't apply to USB devices.
 352                          */
 353                         close(handle->fd);
 354                         return PCAP_ERROR_RFMON_NOTSUP;
 355                 }
 356
 357                 handle->stats_op = usb_stats_linux;
 358                 handle->read_op = usb_read_linux;
 359         }
 360
 361         /*
 362          * "handle->fd" is a real file, so "select()" and "poll()"
 363          * work on it.
 364          */
 365         handle->selectable_fd = handle->fd;
 366
 367         /* for plain binary access and text access we need to allocate the read
 368          * buffer */
 369         handle->buffer = malloc(handle->bufsize);
 370         if (!handle->buffer) {
 371                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 372                          "malloc: %s", pcap_strerror(errno));
 373                 return PCAP_ERROR;
 374         }
 375         return 0;
 376 }
 377
 378 static inline int
 379 ascii_to_int(char c)
 380 {
 381         return c < 'A' ? c- '0': ((c<'a') ? c - 'A' + 10: c-'a'+10);
 382 }
 383
 384 /*
 385  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 386  * <linux-kernel-source>/drivers/usb/mon/mon_text.c for urb string
 387  * format description
 388  */
 389 static int
 390 usb_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 391 {
 392         /* see:
 393         * /usr/src/linux/Documentation/usb/usbmon.txt
 394         * for message format
 395         */
 396         unsigned timestamp;
 397         int tag, cnt, ep_num, dev_addr, dummy, ret, urb_len, data_len;
 398         char etype, pipeid1, pipeid2, status[16], urb_tag, line[USB_LINE_LEN];
 399         char *string = line;
 400         u_char * rawdata = handle->buffer;
 401         struct pcap_pkthdr pkth;
 402         pcap_usb_header* uhdr = (pcap_usb_header*)handle->buffer;
 403         u_char urb_transfer=0;
 404         int incoming=0;
 405
 406         /* ignore interrupt system call errors */
 407         do {
 408                 ret = read(handle->fd, line, USB_LINE_LEN - 1);
 409                 if (handle->break_loop)
 410                 {
 411                         handle->break_loop = 0;
 412                         return -2;
 413                 }
 414         } while ((ret == -1) && (errno == EINTR));
 415         if (ret < 0)
 416         {
 417                 if (errno == EAGAIN)
 418                         return 0;       /* no data there */
 419
 420                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 421                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 422                 return -1;
 423         }
 424
 425         /* read urb header; %n argument may increment return value, but it's
 426         * not mandatory, so does not count on it*/
 427         string[ret] = 0;
 428         ret = sscanf(string, "%x %d %c %c%c:%d:%d %s%n", &tag, &timestamp, &etype,
 429                 &pipeid1, &pipeid2, &dev_addr, &ep_num, status,
 430                 &cnt);
 431         if (ret < 8)
 432         {
 433                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 434                     "Can't parse USB bus message '%s', too few tokens (expected 8 got %d)",
 435                     string, ret);
 436                 return -1;
 437         }
 438         uhdr->id = tag;
 439         uhdr->device_address = dev_addr;
 440         uhdr->bus_id = handle->md.ifindex;
 441         uhdr->status = 0;
 442         string += cnt;
 443
 444         /* don't use usbmon provided timestamp, since it have low precision*/
 445         if (gettimeofday(&pkth.ts, NULL) < 0)
 446         {
 447                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 448                         "Can't get timestamp for message '%s' %d:%s",
 449                         string, errno, strerror(errno));
 450                 return -1;
 451         }
 452         uhdr->ts_sec = pkth.ts.tv_sec;
 453         uhdr->ts_usec = pkth.ts.tv_usec;
 454
 455         /* parse endpoint information */
 456         if (pipeid1 == 'C')
 457                 urb_transfer = URB_CONTROL;
 458         else if (pipeid1 == 'Z')
 459                 urb_transfer = URB_ISOCHRONOUS;
 460         else if (pipeid1 == 'I')
 461                 urb_transfer = URB_INTERRUPT;
 462         else if (pipeid1 == 'B')
 463                 urb_transfer = URB_BULK;
 464         if (pipeid2 == 'i') {
 465                 ep_num |= URB_TRANSFER_IN;
 466                 incoming = 1;
 467         }
 468         if (etype == 'C')
 469                 incoming = !incoming;
 470
 471         /* direction check*/
 472         if (incoming)
 473         {
 474                 if (handle->direction == PCAP_D_OUT)
 475                         return 0;
 476         }
 477         else
 478                 if (handle->direction == PCAP_D_IN)
 479                         return 0;
 480         uhdr->event_type = etype;
 481         uhdr->transfer_type = urb_transfer;
 482         uhdr->endpoint_number = ep_num;
 483         pkth.caplen = sizeof(pcap_usb_header);
 484         rawdata += sizeof(pcap_usb_header);
 485
 486         /* check if this is a setup packet */
 487         ret = sscanf(status, "%d", &dummy);
 488         if (ret != 1)
 489         {
 490                 /* this a setup packet, setup data can be filled with underscore if
 491                 * usbmon has not been able to read them, so we must parse this fields as
 492                 * strings */
 493                 pcap_usb_setup* shdr;
 494                 char str1[3], str2[3], str3[5], str4[5], str5[5];
 495                 ret = sscanf(string, "%s %s %s %s %s%n", str1, str2, str3, str4,
 496                 str5, &cnt);
 497                 if (ret < 5)
 498                 {
 499                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 500                                 "Can't parse USB bus message '%s', too few tokens (expected 5 got %d)",
 501                                 string, ret);
 502                         return -1;
 503                 }
 504                 string += cnt;
 505
 506                 /* try to convert to corresponding integer */
 507                 shdr = &uhdr->setup;
 508                 shdr->bmRequestType = strtoul(str1, 0, 16);
 509                 shdr->bRequest = strtoul(str2, 0, 16);
 510                 shdr->wValue = htols(strtoul(str3, 0, 16));
 511                 shdr->wIndex = htols(strtoul(str4, 0, 16));
 512                 shdr->wLength = htols(strtoul(str5, 0, 16));
 513
 514                 uhdr->setup_flag = 0;
 515         }
 516         else
 517                 uhdr->setup_flag = 1;
 518
 519         /* read urb data */
 520         ret = sscanf(string, " %d%n", &urb_len, &cnt);
 521         if (ret < 1)
 522         {
 523                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 524                   "Can't parse urb length from '%s'", string);
 525                 return -1;
 526         }
 527         string += cnt;
 528
 529         /* urb tag is not present if urb length is 0, so we can stop here
 530          * text parsing */
 531         pkth.len = urb_len+pkth.caplen;
 532         uhdr->urb_len = urb_len;
 533         uhdr->data_flag = 1;
 534         data_len = 0;
 535         if (uhdr->urb_len == 0)
 536                 goto got;
 537
 538         /* check for data presence; data is present if and only if urb tag is '=' */
 539         if (sscanf(string, " %c", &urb_tag) != 1)
 540         {
 541                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 542                         "Can't parse urb tag from '%s'", string);
 543                 return -1;
 544         }
 545
 546         if (urb_tag != '=')
 547                 goto got;
 548
 549         /* skip urb tag and following space */
 550         string += 3;
 551
 552         /* if we reach this point we got some urb data*/
 553         uhdr->data_flag = 0;
 554
 555         /* read all urb data; if urb length is greater then the usbmon internal
 556          * buffer length used by the kernel to spool the URB, we get only
 557          * a partial information.
 558          * At least until linux 2.6.17 there is no way to set usbmon intenal buffer
 559          * length and default value is 130. */
 560         while ((string[0] != 0) && (string[1] != 0) && (pkth.caplen < handle->snapshot))
 561         {
 562                 rawdata[0] = ascii_to_int(string[0]) * 16 + ascii_to_int(string[1]);
 563                 rawdata++;
 564                 string+=2;
 565                 if (string[0] == ' ')
 566                         string++;
 567                 pkth.caplen++;
 568                 data_len++;
 569         }
 570
 571 got:
 572         uhdr->data_len = data_len;
 573         handle->md.packets_read++;
 574         if (pkth.caplen > handle->snapshot)
 575                 pkth.caplen = handle->snapshot;
 576
 577         callback(user, &pkth, handle->buffer);
 578         return 1;
 579 }
 580
 581 static int
 582 usb_inject_linux(pcap_t *handle, const void *buf, size_t size)
 583 {
 584         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
 585                 "USB devices");
 586         return (-1);
 587 }
 588
 589 static int
 590 usb_stats_linux(pcap_t *handle, struct pcap_stat *stats)
 591 {
 592         int dummy, ret, consumed, cnt;
 593         char string[USB_LINE_LEN];
 594         char token[USB_LINE_LEN];
 595         char * ptr = string;
 596         snprintf(string, USB_LINE_LEN, USB_TEXT_DIR"/%ds", handle->md.ifindex);
 597
 598         int fd = open(string, O_RDONLY, 0);
 599         if (fd < 0)
 600         {
 601                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 602                         "Can't open USB stats file %s: %s",
 603                         string, strerror(errno));
 604                 return -1;
 605         }
 606
 607         /* read stats line */
 608         do {
 609                 ret = read(fd, string, USB_LINE_LEN-1);
 610         } while ((ret == -1) && (errno == EINTR));
 611         close(fd);
 612
 613         if (ret < 0)
 614         {
 615                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 616                         "Can't read stats from fd %d ", fd);
 617                 return -1;
 618         }
 619         string[ret] = 0;
 620
 621         /* extract info on dropped urbs */
 622         for (consumed=0; consumed < ret; ) {
 623                 /* from the sscanf man page:
 624                  * The C standard says: "Execution of a %n directive does
 625                  * not increment the assignment count returned at the completion
 626                  * of  execution" but the Corrigendum seems to contradict this.
 627                  * Do not make any assumptions on the effect of %n conversions
 628                  * on the return value and explicitly check for cnt assignmet*/
 629                 cnt = -1;
 630                 int ntok = sscanf(ptr, "%s%n", token, &cnt);
 631                 if ((ntok < 1) || (cnt < 0))
 632                         break;
 633                 consumed += cnt;
 634                 ptr += cnt;
 635                 if (strcmp(token, "nreaders") == 0)
 636                         ret = sscanf(ptr, "%d", &stats->ps_drop);
 637                 else
 638                         ret = sscanf(ptr, "%d", &dummy);
 639                 if (ntok != 1)
 640                         break;
 641                 consumed += cnt;
 642                 ptr += cnt;
 643         }
 644
 645         stats->ps_recv = handle->md.packets_read;
 646         stats->ps_ifdrop = 0;
 647         return 0;
 648 }
 649
 650 static int
 651 usb_setfilter_linux(pcap_t *p, struct bpf_program *fp)
 652 {
 653         return 0;
 654 }
 655
 656 static int
 657 usb_setdirection_linux(pcap_t *p, pcap_direction_t d)
 658 {
 659         p->direction = d;
 660         return 0;
 661 }
 662
 663
 664 static int
 665 usb_stats_linux_bin(pcap_t *handle, struct pcap_stat *stats)
 666 {
 667         int ret;
 668         struct mon_bin_stats st;
 669         ret = ioctl(handle->fd, MON_IOCG_STATS, &st);
 670         if (ret < 0)
 671         {
 672                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 673                         "Can't read stats from fd %d:%s ", handle->fd, strerror(errno));
 674                 return -1;
 675         }
 676
 677         stats->ps_recv = handle->md.packets_read + st.queued;
 678         stats->ps_ifdrop = 0;
 679         stats->ps_drop = st.dropped;
 680         return 0;
 681 }
 682
 683 /*
 684  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 685  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 686  */
 687 static int
 688 usb_read_linux_bin(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 689 {
 690         struct mon_bin_get info;
 691         int ret;
 692         struct pcap_pkthdr pkth;
 693         int clen = handle->snapshot - sizeof(pcap_usb_header);
 694
 695         /* the usb header is going to be part of 'packet' data*/
 696         info.hdr = (pcap_usb_header*) handle->buffer;
 697         info.data = handle->buffer + sizeof(pcap_usb_header);
 698         info.data_len = clen;
 699
 700         /* ignore interrupt system call errors */
 701         do {
 702                 ret = ioctl(handle->fd, MON_IOCX_GET, &info);
 703                 if (handle->break_loop)
 704                 {
 705                         handle->break_loop = 0;
 706                         return -2;
 707                 }
 708         } while ((ret == -1) && (errno == EINTR));
 709         if (ret < 0)
 710         {
 711                 if (errno == EAGAIN)
 712                         return 0;       /* no data there */
 713
 714                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 715                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 716                 return -1;
 717         }
 718
 719         /* we can get less that than really captured from kernel, depending on
 720          * snaplen, so adjust header accordingly */
 721         if (info.hdr->data_len < clen)
 722                 clen = info.hdr->data_len;
 723         info.hdr->data_len = clen;
 724         pkth.caplen = clen + sizeof(pcap_usb_header);
 725         pkth.len = info.hdr->data_len + sizeof(pcap_usb_header);
 726         pkth.ts.tv_sec = info.hdr->ts_sec;
 727         pkth.ts.tv_usec = info.hdr->ts_usec;
 728
 729         handle->md.packets_read++;
 730         callback(user, &pkth, handle->buffer);
 731         return 1;
 732 }
 733
 734 /*
 735  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 736  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 737  */
 738 #define VEC_SIZE 32
 739 static int
 740 usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 741 {
 742         struct mon_bin_mfetch fetch;
 743         int32_t vec[VEC_SIZE];
 744         struct pcap_pkthdr pkth;
 745         pcap_usb_header* hdr;
 746         int nflush = 0;
 747         int packets = 0;
 748         int clen, max_clen;
 749
 750         max_clen = handle->snapshot - sizeof(pcap_usb_header);
 751
 752         for (;;) {
 753                 int i, ret;
 754                 int limit = max_packets - packets;
 755                 if (limit <= 0)
 756                         limit = VEC_SIZE;
 757                 if (limit > VEC_SIZE)
 758                         limit = VEC_SIZE;
 759
 760                 /* try to fetch as many events as possible*/
 761                 fetch.offvec = vec;
 762                 fetch.nfetch = limit;
 763                 fetch.nflush = nflush;
 764                 /* ignore interrupt system call errors */
 765                 do {
 766                         ret = ioctl(handle->fd, MON_IOCX_MFETCH, &fetch);
 767                         if (handle->break_loop)
 768                         {
 769                                 handle->break_loop = 0;
 770                                 return -2;
 771                         }
 772                 } while ((ret == -1) && (errno == EINTR));
 773                 if (ret < 0)
 774                 {
 775                         if (errno == EAGAIN)
 776                                 return 0;       /* no data there */
 777
 778                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 779                             "Can't mfetch fd %d: %s", handle->fd, strerror(errno));
 780                         return -1;
 781                 }
 782
 783                 /* keep track of processed events, we will flush them later */
 784                 nflush = fetch.nfetch;
 785                 for (i=0; i<fetch.nfetch; ++i) {
 786                         /* discard filler */
 787                         hdr = (pcap_usb_header*) &handle->buffer[vec[i]];
 788                         if (hdr->event_type == '@')
 789                                 continue;
 790
 791                         /* we can get less that than really captured from kernel, depending on
 792                         * snaplen, so adjust header accordingly */
 793                         clen = max_clen;
 794                         if (hdr->data_len < clen)
 795                                 clen = hdr->data_len;
 796
 797                         /* get packet info from header*/
 798                         pkth.caplen = clen + sizeof(pcap_usb_header_mmapped);
 799                         pkth.len = hdr->data_len + sizeof(pcap_usb_header_mmapped);
 800                         pkth.ts.tv_sec = hdr->ts_sec;
 801                         pkth.ts.tv_usec = hdr->ts_usec;
 802
 803                         handle->md.packets_read++;
 804                         callback(user, &pkth, (u_char*) hdr);
 805                         packets++;
 806                 }
 807
 808                 /* with max_packets <= 0 we stop afer the first chunk*/
 809                 if ((max_packets <= 0) || (packets == max_packets))
 810                         break;
 811         }
 812
 813         /* flush pending events*/
 814         ioctl(handle->fd, MON_IOCH_MFLUSH, nflush);
 815         return packets;
 816 }
 817
 818 static void
 819 usb_cleanup_linux_mmap(pcap_t* handle)
 820 {
 821         /* buffer must not be freed because it's memory mapped */
 822         /* XXX - does it need to be unmapped? */
 823         handle->buffer = NULL;
 824         pcap_cleanup_live_common(handle);
 825 }