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_OLD "/sys/kernel/debug/usbmon"
  69 #define USB_TEXT_DIR "/sys/kernel/debug/usb/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->md.mmapbuflen = len;
 206         handle->md.mmapbuf = mmap(0, handle->md.mmapbuflen, PROT_READ,
 207             MAP_SHARED, handle->fd, 0);
 208         return handle->md.mmapbuf != MAP_FAILED;
 209 }
 210
 211 #define CTRL_TIMEOUT    (5*1000)        /* milliseconds */
 212
 213 #define USB_DIR_IN              0x80
 214 #define USB_TYPE_STANDARD       0x00
 215 #define USB_RECIP_DEVICE        0x00
 216
 217 #define USB_REQ_GET_DESCRIPTOR  6
 218
 219 #define USB_DT_DEVICE           1
 220
 221 /* probe the descriptors of the devices attached to the bus */
 222 /* the descriptors will end up in the captured packet stream */
 223 /* and be decoded by external apps like wireshark */
 224 /* without these identifying probes packet data can't be fully decoded */
 225 static void
 226 probe_devices(int bus)
 227 {
 228         struct usbdevfs_ctrltransfer ctrl;
 229         struct dirent* data;
 230         int ret = 0;
 231         char buf[40];
 232         DIR* dir;
 233
 234         /* scan usb bus directories for device nodes */
 235         snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d", bus);
 236         dir = opendir(buf);
 237         if (!dir)
 238                 return;
 239
 240         while ((ret >= 0) && ((data = readdir(dir)) != 0)) {
 241                 int fd;
 242                 char* name = data->d_name;
 243
 244                 if (name[0] == '.')
 245                         continue;
 246
 247                 snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d/%s", bus, data->d_name);
 248
 249                 fd = open(buf, O_RDWR);
 250                 if (fd == -1)
 251                         continue;
 252
 253                 /*
 254                  * Sigh.  Different kernels have different member names
 255                  * for this structure.
 256                  */
 257 #ifdef HAVE_USBDEVFS_CTRLTRANSFER_BREQUESTTYPE
 258                 ctrl.bRequestType = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
 259                 ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
 260                 ctrl.wValue = USB_DT_DEVICE << 8;
 261                 ctrl.wIndex = 0;
 262                 ctrl.wLength = sizeof(buf);
 263 #else
 264                 ctrl.requesttype = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
 265                 ctrl.request = USB_REQ_GET_DESCRIPTOR;
 266                 ctrl.value = USB_DT_DEVICE << 8;
 267                 ctrl.index = 0;
 268                 ctrl.length = sizeof(buf);
 269 #endif
 270                 ctrl.data = buf;
 271                 ctrl.timeout = CTRL_TIMEOUT;
 272
 273                 ret = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
 274
 275                 close(fd);
 276         }
 277         closedir(dir);
 278 }
 279
 280 pcap_t *
 281 usb_create(const char *device, char *ebuf)
 282 {
 283         pcap_t *p;
 284
 285         p = pcap_create_common(device, ebuf);
 286         if (p == NULL)
 287                 return (NULL);
 288
 289         p->activate_op = usb_activate;
 290         return (p);
 291 }
 292
 293 static int
 294 usb_activate(pcap_t* handle)
 295 {
 296         char            full_path[USB_LINE_LEN];
 297
 298         /* Initialize some components of the pcap structure. */
 299         handle->bufsize = handle->snapshot;
 300         handle->offset = 0;
 301         handle->linktype = DLT_USB_LINUX;
 302
 303         handle->inject_op = usb_inject_linux;
 304         handle->setfilter_op = usb_setfilter_linux;
 305         handle->setdirection_op = usb_setdirection_linux;
 306         handle->set_datalink_op = NULL; /* can't change data link type */
 307         handle->getnonblock_op = pcap_getnonblock_fd;
 308         handle->setnonblock_op = pcap_setnonblock_fd;
 309
 310         /*get usb bus index from device name */
 311         if (sscanf(handle->opt.source, USB_IFACE"%d", &handle->md.ifindex) != 1)
 312         {
 313                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 314                         "Can't get USB bus index from %s", handle->opt.source);
 315                 return PCAP_ERROR;
 316         }
 317
 318         /*now select the read method: try to open binary interface */
 319         snprintf(full_path, USB_LINE_LEN, LINUX_USB_MON_DEV"%d", handle->md.ifindex);
 320         handle->fd = open(full_path, O_RDONLY, 0);
 321         if (handle->fd >= 0)
 322         {
 323                 if (handle->opt.rfmon) {
 324                         /*
 325                          * Monitor mode doesn't apply to USB devices.
 326                          */
 327                         close(handle->fd);
 328                         return PCAP_ERROR_RFMON_NOTSUP;
 329                 }
 330
 331                 /* binary api is available, try to use fast mmap access */
 332                 if (usb_mmap(handle)) {
 333                         handle->linktype = DLT_USB_LINUX_MMAPPED;
 334                         handle->stats_op = usb_stats_linux_bin;
 335                         handle->read_op = usb_read_linux_mmap;
 336                         handle->cleanup_op = usb_cleanup_linux_mmap;
 337                         probe_devices(handle->md.ifindex);
 338
 339                         /*
 340                          * "handle->fd" is a real file, so "select()" and
 341                          * "poll()" work on it.
 342                          */
 343                         handle->selectable_fd = handle->fd;
 344                         return 0;
 345                 }
 346
 347                 /* can't mmap, use plain binary interface access */
 348                 handle->stats_op = usb_stats_linux_bin;
 349                 handle->read_op = usb_read_linux_bin;
 350                 probe_devices(handle->md.ifindex);
 351         }
 352         else {
 353                 /*Binary interface not available, try open text interface */
 354                 snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR"/%dt", handle->md.ifindex);
 355                 handle->fd = open(full_path, O_RDONLY, 0);
 356                 if (handle->fd < 0)
 357                 {
 358                         if (errno == ENOENT)
 359                         {
 360                                 /*
 361                                  * Not found at the new location; try
 362                                  * the old location.
 363                                  */
 364                                 snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR_OLD"/%dt", handle->md.ifindex);
 365                                 handle->fd = open(full_path, O_RDONLY, 0);
 366                         }
 367                         if (handle->fd < 0) {
 368                                 /* no more fallback, give it up*/
 369                                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 370                                         "Can't open USB bus file %s: %s", full_path, strerror(errno));
 371                                 return PCAP_ERROR;
 372                         }
 373                 }
 374
 375                 if (handle->opt.rfmon) {
 376                         /*
 377                          * Monitor mode doesn't apply to USB devices.
 378                          */
 379                         close(handle->fd);
 380                         return PCAP_ERROR_RFMON_NOTSUP;
 381                 }
 382
 383                 handle->stats_op = usb_stats_linux;
 384                 handle->read_op = usb_read_linux;
 385         }
 386
 387         /*
 388          * "handle->fd" is a real file, so "select()" and "poll()"
 389          * work on it.
 390          */
 391         handle->selectable_fd = handle->fd;
 392
 393         /* for plain binary access and text access we need to allocate the read
 394          * buffer */
 395         handle->buffer = malloc(handle->bufsize);
 396         if (!handle->buffer) {
 397                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 398                          "malloc: %s", pcap_strerror(errno));
 399                 close(handle->fd);
 400                 return PCAP_ERROR;
 401         }
 402         return 0;
 403 }
 404
 405 static inline int
 406 ascii_to_int(char c)
 407 {
 408         return c < 'A' ? c- '0': ((c<'a') ? c - 'A' + 10: c-'a'+10);
 409 }
 410
 411 /*
 412  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 413  * <linux-kernel-source>/drivers/usb/mon/mon_text.c for urb string
 414  * format description
 415  */
 416 static int
 417 usb_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 418 {
 419         /* see:
 420         * /usr/src/linux/Documentation/usb/usbmon.txt
 421         * for message format
 422         */
 423         unsigned timestamp;
 424         int tag, cnt, ep_num, dev_addr, dummy, ret, urb_len, data_len;
 425         char etype, pipeid1, pipeid2, status[16], urb_tag, line[USB_LINE_LEN];
 426         char *string = line;
 427         u_char * rawdata = handle->buffer;
 428         struct pcap_pkthdr pkth;
 429         pcap_usb_header* uhdr = (pcap_usb_header*)handle->buffer;
 430         u_char urb_transfer=0;
 431         int incoming=0;
 432
 433         /* ignore interrupt system call errors */
 434         do {
 435                 ret = read(handle->fd, line, USB_LINE_LEN - 1);
 436                 if (handle->break_loop)
 437                 {
 438                         handle->break_loop = 0;
 439                         return -2;
 440                 }
 441         } while ((ret == -1) && (errno == EINTR));
 442         if (ret < 0)
 443         {
 444                 if (errno == EAGAIN)
 445                         return 0;       /* no data there */
 446
 447                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 448                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 449                 return -1;
 450         }
 451
 452         /* read urb header; %n argument may increment return value, but it's
 453         * not mandatory, so does not count on it*/
 454         string[ret] = 0;
 455         ret = sscanf(string, "%x %d %c %c%c:%d:%d %s%n", &tag, &timestamp, &etype,
 456                 &pipeid1, &pipeid2, &dev_addr, &ep_num, status,
 457                 &cnt);
 458         if (ret < 8)
 459         {
 460                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 461                     "Can't parse USB bus message '%s', too few tokens (expected 8 got %d)",
 462                     string, ret);
 463                 return -1;
 464         }
 465         uhdr->id = tag;
 466         uhdr->device_address = dev_addr;
 467         uhdr->bus_id = handle->md.ifindex;
 468         uhdr->status = 0;
 469         string += cnt;
 470
 471         /* don't use usbmon provided timestamp, since it have low precision*/
 472         if (gettimeofday(&pkth.ts, NULL) < 0)
 473         {
 474                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 475                         "Can't get timestamp for message '%s' %d:%s",
 476                         string, errno, strerror(errno));
 477                 return -1;
 478         }
 479         uhdr->ts_sec = pkth.ts.tv_sec;
 480         uhdr->ts_usec = pkth.ts.tv_usec;
 481
 482         /* parse endpoint information */
 483         if (pipeid1 == 'C')
 484                 urb_transfer = URB_CONTROL;
 485         else if (pipeid1 == 'Z')
 486                 urb_transfer = URB_ISOCHRONOUS;
 487         else if (pipeid1 == 'I')
 488                 urb_transfer = URB_INTERRUPT;
 489         else if (pipeid1 == 'B')
 490                 urb_transfer = URB_BULK;
 491         if (pipeid2 == 'i') {
 492                 ep_num |= URB_TRANSFER_IN;
 493                 incoming = 1;
 494         }
 495         if (etype == 'C')
 496                 incoming = !incoming;
 497
 498         /* direction check*/
 499         if (incoming)
 500         {
 501                 if (handle->direction == PCAP_D_OUT)
 502                         return 0;
 503         }
 504         else
 505                 if (handle->direction == PCAP_D_IN)
 506                         return 0;
 507         uhdr->event_type = etype;
 508         uhdr->transfer_type = urb_transfer;
 509         uhdr->endpoint_number = ep_num;
 510         pkth.caplen = sizeof(pcap_usb_header);
 511         rawdata += sizeof(pcap_usb_header);
 512
 513         /* check if this is a setup packet */
 514         ret = sscanf(status, "%d", &dummy);
 515         if (ret != 1)
 516         {
 517                 /* this a setup packet, setup data can be filled with underscore if
 518                 * usbmon has not been able to read them, so we must parse this fields as
 519                 * strings */
 520                 pcap_usb_setup* shdr;
 521                 char str1[3], str2[3], str3[5], str4[5], str5[5];
 522                 ret = sscanf(string, "%s %s %s %s %s%n", str1, str2, str3, str4,
 523                 str5, &cnt);
 524                 if (ret < 5)
 525                 {
 526                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 527                                 "Can't parse USB bus message '%s', too few tokens (expected 5 got %d)",
 528                                 string, ret);
 529                         return -1;
 530                 }
 531                 string += cnt;
 532
 533                 /* try to convert to corresponding integer */
 534                 shdr = &uhdr->setup;
 535                 shdr->bmRequestType = strtoul(str1, 0, 16);
 536                 shdr->bRequest = strtoul(str2, 0, 16);
 537                 shdr->wValue = htols(strtoul(str3, 0, 16));
 538                 shdr->wIndex = htols(strtoul(str4, 0, 16));
 539                 shdr->wLength = htols(strtoul(str5, 0, 16));
 540
 541                 uhdr->setup_flag = 0;
 542         }
 543         else
 544                 uhdr->setup_flag = 1;
 545
 546         /* read urb data */
 547         ret = sscanf(string, " %d%n", &urb_len, &cnt);
 548         if (ret < 1)
 549         {
 550                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 551                   "Can't parse urb length from '%s'", string);
 552                 return -1;
 553         }
 554         string += cnt;
 555
 556         /* urb tag is not present if urb length is 0, so we can stop here
 557          * text parsing */
 558         pkth.len = urb_len+pkth.caplen;
 559         uhdr->urb_len = urb_len;
 560         uhdr->data_flag = 1;
 561         data_len = 0;
 562         if (uhdr->urb_len == 0)
 563                 goto got;
 564
 565         /* check for data presence; data is present if and only if urb tag is '=' */
 566         if (sscanf(string, " %c", &urb_tag) != 1)
 567         {
 568                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 569                         "Can't parse urb tag from '%s'", string);
 570                 return -1;
 571         }
 572
 573         if (urb_tag != '=')
 574                 goto got;
 575
 576         /* skip urb tag and following space */
 577         string += 3;
 578
 579         /* if we reach this point we got some urb data*/
 580         uhdr->data_flag = 0;
 581
 582         /* read all urb data; if urb length is greater then the usbmon internal
 583          * buffer length used by the kernel to spool the URB, we get only
 584          * a partial information.
 585          * At least until linux 2.6.17 there is no way to set usbmon intenal buffer
 586          * length and default value is 130. */
 587         while ((string[0] != 0) && (string[1] != 0) && (pkth.caplen < handle->snapshot))
 588         {
 589                 rawdata[0] = ascii_to_int(string[0]) * 16 + ascii_to_int(string[1]);
 590                 rawdata++;
 591                 string+=2;
 592                 if (string[0] == ' ')
 593                         string++;
 594                 pkth.caplen++;
 595                 data_len++;
 596         }
 597
 598 got:
 599         uhdr->data_len = data_len;
 600         handle->md.packets_read++;
 601         if (pkth.caplen > handle->snapshot)
 602                 pkth.caplen = handle->snapshot;
 603
 604         callback(user, &pkth, handle->buffer);
 605         return 1;
 606 }
 607
 608 static int
 609 usb_inject_linux(pcap_t *handle, const void *buf, size_t size)
 610 {
 611         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
 612                 "USB devices");
 613         return (-1);
 614 }
 615
 616 static int
 617 usb_stats_linux(pcap_t *handle, struct pcap_stat *stats)
 618 {
 619         int dummy, ret, consumed, cnt;
 620         char string[USB_LINE_LEN];
 621         char token[USB_LINE_LEN];
 622         char * ptr = string;
 623         int fd;
 624
 625         snprintf(string, USB_LINE_LEN, USB_TEXT_DIR"/%ds", handle->md.ifindex);
 626         fd = open(string, O_RDONLY, 0);
 627         if (fd < 0)
 628         {
 629                 if (errno == ENOENT)
 630                 {
 631                         /*
 632                          * Not found at the new location; try the old
 633                          * location.
 634                          */
 635                         snprintf(string, USB_LINE_LEN, USB_TEXT_DIR_OLD"/%ds", handle->md.ifindex);
 636                         fd = open(string, O_RDONLY, 0);
 637                 }
 638                 if (fd < 0) {
 639                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 640                                 "Can't open USB stats file %s: %s",
 641                                 string, strerror(errno));
 642                         return -1;
 643                 }
 644         }
 645
 646         /* read stats line */
 647         do {
 648                 ret = read(fd, string, USB_LINE_LEN-1);
 649         } while ((ret == -1) && (errno == EINTR));
 650         close(fd);
 651
 652         if (ret < 0)
 653         {
 654                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 655                         "Can't read stats from fd %d ", fd);
 656                 return -1;
 657         }
 658         string[ret] = 0;
 659
 660         /* extract info on dropped urbs */
 661         for (consumed=0; consumed < ret; ) {
 662                 /* from the sscanf man page:
 663                  * The C standard says: "Execution of a %n directive does
 664                  * not increment the assignment count returned at the completion
 665                  * of  execution" but the Corrigendum seems to contradict this.
 666                  * Do not make any assumptions on the effect of %n conversions
 667                  * on the return value and explicitly check for cnt assignmet*/
 668                 int ntok;
 669
 670                 cnt = -1;
 671                 ntok = sscanf(ptr, "%s%n", token, &cnt);
 672                 if ((ntok < 1) || (cnt < 0))
 673                         break;
 674                 consumed += cnt;
 675                 ptr += cnt;
 676                 if (strcmp(token, "nreaders") == 0)
 677                         ret = sscanf(ptr, "%d", &stats->ps_drop);
 678                 else
 679                         ret = sscanf(ptr, "%d", &dummy);
 680                 if (ntok != 1)
 681                         break;
 682                 consumed += cnt;
 683                 ptr += cnt;
 684         }
 685
 686         stats->ps_recv = handle->md.packets_read;
 687         stats->ps_ifdrop = 0;
 688         return 0;
 689 }
 690
 691 static int
 692 usb_setfilter_linux(pcap_t *p, struct bpf_program *fp)
 693 {
 694         return 0;
 695 }
 696
 697 static int
 698 usb_setdirection_linux(pcap_t *p, pcap_direction_t d)
 699 {
 700         p->direction = d;
 701         return 0;
 702 }
 703
 704
 705 static int
 706 usb_stats_linux_bin(pcap_t *handle, struct pcap_stat *stats)
 707 {
 708         int ret;
 709         struct mon_bin_stats st;
 710         ret = ioctl(handle->fd, MON_IOCG_STATS, &st);
 711         if (ret < 0)
 712         {
 713                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 714                         "Can't read stats from fd %d:%s ", handle->fd, strerror(errno));
 715                 return -1;
 716         }
 717
 718         stats->ps_recv = handle->md.packets_read + st.queued;
 719         stats->ps_drop = st.dropped;
 720         stats->ps_ifdrop = 0;
 721         return 0;
 722 }
 723
 724 /*
 725  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 726  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 727  */
 728 static int
 729 usb_read_linux_bin(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 730 {
 731         struct mon_bin_get info;
 732         int ret;
 733         struct pcap_pkthdr pkth;
 734         int clen = handle->snapshot - sizeof(pcap_usb_header);
 735
 736         /* the usb header is going to be part of 'packet' data*/
 737         info.hdr = (pcap_usb_header*) handle->buffer;
 738         info.data = handle->buffer + sizeof(pcap_usb_header);
 739         info.data_len = clen;
 740
 741         /* ignore interrupt system call errors */
 742         do {
 743                 ret = ioctl(handle->fd, MON_IOCX_GET, &info);
 744                 if (handle->break_loop)
 745                 {
 746                         handle->break_loop = 0;
 747                         return -2;
 748                 }
 749         } while ((ret == -1) && (errno == EINTR));
 750         if (ret < 0)
 751         {
 752                 if (errno == EAGAIN)
 753                         return 0;       /* no data there */
 754
 755                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 756                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 757                 return -1;
 758         }
 759
 760         /* we can get less that than really captured from kernel, depending on
 761          * snaplen, so adjust header accordingly */
 762         if (info.hdr->data_len < clen)
 763                 clen = info.hdr->data_len;
 764         info.hdr->data_len = clen;
 765         pkth.caplen = clen + sizeof(pcap_usb_header);
 766         pkth.len = info.hdr->data_len + sizeof(pcap_usb_header);
 767         pkth.ts.tv_sec = info.hdr->ts_sec;
 768         pkth.ts.tv_usec = info.hdr->ts_usec;
 769
 770         handle->md.packets_read++;
 771         callback(user, &pkth, handle->buffer);
 772         return 1;
 773 }
 774
 775 /*
 776  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 777  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 778  */
 779 #define VEC_SIZE 32
 780 static int
 781 usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 782 {
 783         struct mon_bin_mfetch fetch;
 784         int32_t vec[VEC_SIZE];
 785         struct pcap_pkthdr pkth;
 786         pcap_usb_header* hdr;
 787         int nflush = 0;
 788         int packets = 0;
 789         int clen, max_clen;
 790
 791         max_clen = handle->snapshot - sizeof(pcap_usb_header);
 792
 793         for (;;) {
 794                 int i, ret;
 795                 int limit = max_packets - packets;
 796                 if (limit <= 0)
 797                         limit = VEC_SIZE;
 798                 if (limit > VEC_SIZE)
 799                         limit = VEC_SIZE;
 800
 801                 /* try to fetch as many events as possible*/
 802                 fetch.offvec = vec;
 803                 fetch.nfetch = limit;
 804                 fetch.nflush = nflush;
 805                 /* ignore interrupt system call errors */
 806                 do {
 807                         ret = ioctl(handle->fd, MON_IOCX_MFETCH, &fetch);
 808                         if (handle->break_loop)
 809                         {
 810                                 handle->break_loop = 0;
 811                                 return -2;
 812                         }
 813                 } while ((ret == -1) && (errno == EINTR));
 814                 if (ret < 0)
 815                 {
 816                         if (errno == EAGAIN)
 817                                 return 0;       /* no data there */
 818
 819                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 820                             "Can't mfetch fd %d: %s", handle->fd, strerror(errno));
 821                         return -1;
 822                 }
 823
 824                 /* keep track of processed events, we will flush them later */
 825                 nflush = fetch.nfetch;
 826                 for (i=0; i<fetch.nfetch; ++i) {
 827                         /* discard filler */
 828                         hdr = (pcap_usb_header*) &handle->md.mmapbuf[vec[i]];
 829                         if (hdr->event_type == '@')
 830                                 continue;
 831
 832                         /* we can get less that than really captured from kernel, depending on
 833                         * snaplen, so adjust header accordingly */
 834                         clen = max_clen;
 835                         if (hdr->data_len < clen)
 836                                 clen = hdr->data_len;
 837
 838                         /* get packet info from header*/
 839                         pkth.caplen = clen + sizeof(pcap_usb_header_mmapped);
 840                         pkth.len = hdr->data_len + sizeof(pcap_usb_header_mmapped);
 841                         pkth.ts.tv_sec = hdr->ts_sec;
 842                         pkth.ts.tv_usec = hdr->ts_usec;
 843
 844                         handle->md.packets_read++;
 845                         callback(user, &pkth, (u_char*) hdr);
 846                         packets++;
 847                 }
 848
 849                 /* with max_packets <= 0 we stop afer the first chunk*/
 850                 if ((max_packets <= 0) || (packets == max_packets))
 851                         break;
 852         }
 853
 854         /* flush pending events*/
 855         ioctl(handle->fd, MON_IOCH_MFLUSH, nflush);
 856         return packets;
 857 }
 858
 859 static void
 860 usb_cleanup_linux_mmap(pcap_t* handle)
 861 {
 862         /* if we have a memory-mapped buffer, unmap it */
 863         if (handle->md.mmapbuf != NULL) {
 864                 munmap(handle->md.mmapbuf, handle->md.mmapbuflen);
 865                 handle->md.mmapbuf = NULL;
 866         }
 867         pcap_cleanup_live_common(handle);
 868 }