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 1.24 2008-04-14 21:06:09 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
  64 #define USB_IFACE "usb"
  65 #define USB_TEXT_DIR "/sys/kernel/debug/usbmon"
  66 #define USB_BUS_DIR "/proc/bus/usb"
  67 #define USB_LINE_LEN 4096
  68
  69
  70 #define PIPE_IN                 0x80
  71 #define PIPE_ISOCHRONOUS        0
  72 #define PIPE_INTERRUPT          1
  73 #define PIPE_CONTROL            2
  74 #define PIPE_BULK               3
  75
  76 #if __BYTE_ORDER == __LITTLE_ENDIAN
  77 #define htols(s) s
  78 #define htoll(l) l
  79 #define htol64(ll) ll
  80 #else
  81 #define htols(s) bswap_16(s)
  82 #define htoll(l) bswap_32(l)
  83 #define htol64(ll) bswap_64(ll)
  84 #endif
  85
  86 struct mon_bin_stats {
  87         u_int32_t queued;
  88         u_int32_t dropped;
  89 };
  90
  91 struct mon_bin_get {
  92         pcap_usb_header *hdr;
  93         void *data;
  94         size_t data_len;   /* Length of data (can be zero) */
  95 };
  96
  97 struct mon_bin_mfetch {
  98         int32_t *offvec;   /* Vector of events fetched */
  99         int32_t nfetch;    /* Number of events to fetch (out: fetched) */
 100         int32_t nflush;    /* Number of events to flush */
 101 };
 102
 103 #define MON_IOC_MAGIC 0x92
 104
 105 #define MON_IOCQ_URB_LEN _IO(MON_IOC_MAGIC, 1)
 106 #define MON_IOCX_URB  _IOWR(MON_IOC_MAGIC, 2, struct mon_bin_hdr)
 107 #define MON_IOCG_STATS _IOR(MON_IOC_MAGIC, 3, struct mon_bin_stats)
 108 #define MON_IOCT_RING_SIZE _IO(MON_IOC_MAGIC, 4)
 109 #define MON_IOCQ_RING_SIZE _IO(MON_IOC_MAGIC, 5)
 110 #define MON_IOCX_GET   _IOW(MON_IOC_MAGIC, 6, struct mon_bin_get)
 111 #define MON_IOCX_MFETCH _IOWR(MON_IOC_MAGIC, 7, struct mon_bin_mfetch)
 112 #define MON_IOCH_MFLUSH _IO(MON_IOC_MAGIC, 8)
 113
 114 #define MON_BIN_SETUP   0x1 /* setup hdr is present*/
 115 #define MON_BIN_SETUP_ZERO      0x2 /* setup buffer is not available */
 116 #define MON_BIN_DATA_ZERO       0x4 /* data buffer is not available */
 117 #define MON_BIN_ERROR   0x8
 118
 119 /* forward declaration */
 120 static int usb_activate(pcap_t *);
 121 static int usb_stats_linux(pcap_t *, struct pcap_stat *);
 122 static int usb_stats_linux_bin(pcap_t *, struct pcap_stat *);
 123 static int usb_read_linux(pcap_t *, int , pcap_handler , u_char *);
 124 static int usb_read_linux_bin(pcap_t *, int , pcap_handler , u_char *);
 125 static int usb_read_linux_mmap(pcap_t *, int , pcap_handler , u_char *);
 126 static int usb_inject_linux(pcap_t *, const void *, size_t);
 127 static int usb_setfilter_linux(pcap_t *, struct bpf_program *);
 128 static int usb_setdirection_linux(pcap_t *, pcap_direction_t);
 129 static void usb_cleanup_linux_mmap(pcap_t *);
 130
 131 /* facility to add an USB device to the device list*/
 132 static int
 133 usb_dev_add(pcap_if_t** alldevsp, int n, char *err_str)
 134 {
 135         char dev_name[10];
 136         char dev_descr[30];
 137         snprintf(dev_name, 10, USB_IFACE"%d", n);
 138         snprintf(dev_descr, 30, "USB bus number %d", n);
 139
 140         if (pcap_add_if(alldevsp, dev_name, 0,
 141             dev_descr, err_str) < 0)
 142                 return -1;
 143         return 0;
 144 }
 145
 146 int
 147 usb_platform_finddevs(pcap_if_t **alldevsp, char *err_str)
 148 {
 149         struct dirent* data;
 150         int ret = 0;
 151         DIR* dir;
 152
 153         /* scan procfs usb bus directory */
 154         dir = opendir(USB_BUS_DIR);
 155         if (!dir) return 0;
 156         while ((ret == 0) && ((data = readdir(dir)) != 0)) {
 157                 int n;
 158                 char* name = data->d_name;
 159                 int len = strlen(name);
 160
 161                 /* if this file name does not end with a number it's not of our interest */
 162                 if ((len < 1) || !isdigit(name[--len]))
 163                         continue;
 164                 while (isdigit(name[--len]));
 165                 if (sscanf(&name[len+1], "%d", &n) != 1)
 166                         continue;
 167
 168                 ret = usb_dev_add(alldevsp, n, err_str);
 169         }
 170
 171         closedir(dir);
 172         return ret;
 173 }
 174
 175 static
 176 int usb_mmap(pcap_t* handle)
 177 {
 178         int len = ioctl(handle->fd, MON_IOCQ_RING_SIZE);
 179         if (len < 0)
 180                 return 0;
 181
 182         handle->buffer = mmap(0, len, PROT_READ, MAP_SHARED, handle->fd, 0);
 183         return handle->buffer != MAP_FAILED;
 184 }
 185
 186 pcap_t *
 187 usb_create(const char *device, char *ebuf)
 188 {
 189         pcap_t *p;
 190
 191         p = pcap_create_common(device, ebuf);
 192         if (p == NULL)
 193                 return (NULL);
 194
 195         p->activate_op = usb_activate;
 196         return (p);
 197 }
 198
 199 static int
 200 usb_activate(pcap_t* handle)
 201 {
 202         char            full_path[USB_LINE_LEN];
 203
 204         /* Initialize some components of the pcap structure. */
 205         handle->bufsize = handle->snapshot;
 206         handle->offset = 0;
 207         handle->linktype = DLT_USB_LINUX;
 208
 209         handle->inject_op = usb_inject_linux;
 210         handle->setfilter_op = usb_setfilter_linux;
 211         handle->setdirection_op = usb_setdirection_linux;
 212         handle->set_datalink_op = NULL; /* can't change data link type */
 213         handle->getnonblock_op = pcap_getnonblock_fd;
 214         handle->setnonblock_op = pcap_setnonblock_fd;
 215
 216         /*get usb bus index from device name */
 217         if (sscanf(handle->opt.source, USB_IFACE"%d", &handle->md.ifindex) != 1)
 218         {
 219                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 220                         "Can't get USB bus index from %s", handle->opt.source);
 221                 return PCAP_ERROR;
 222         }
 223
 224         /*now select the read method: try to open binary interface */
 225         snprintf(full_path, USB_LINE_LEN, LINUX_USB_MON_DEV"%d", handle->md.ifindex);
 226         handle->fd = open(full_path, O_RDONLY, 0);
 227         if (handle->fd >= 0)
 228         {
 229                 if (handle->opt.rfmon) {
 230                         /*
 231                          * Monitor mode doesn't apply to USB devices.
 232                          */
 233                         return PCAP_ERROR_RFMON_NOTSUP;
 234                 }
 235
 236                 /* binary api is available, try to use fast mmap access */
 237                 if (usb_mmap(handle)) {
 238                         handle->stats_op = usb_stats_linux_bin;
 239                         handle->read_op = usb_read_linux_mmap;
 240                         handle->cleanup_op = usb_cleanup_linux_mmap;
 241
 242                         /*
 243                          * "handle->fd" is a real file, so "select()" and
 244                          * "poll()" work on it.
 245                          */
 246                         handle->selectable_fd = handle->fd;
 247                         return 0;
 248                 }
 249
 250                 /* can't mmap, use plain binary interface access */
 251                 handle->stats_op = usb_stats_linux_bin;
 252                 handle->read_op = usb_read_linux_bin;
 253         }
 254         else {
 255                 /*Binary interface not available, try open text interface */
 256                 snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR"/%dt", handle->md.ifindex);
 257                 handle->fd = open(full_path, O_RDONLY, 0);
 258                 if (handle->fd < 0)
 259                 {
 260                         /* no more fallback, give it up*/
 261                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 262                                 "Can't open USB bus file %s: %s", full_path, strerror(errno));
 263                         return PCAP_ERROR;
 264                 }
 265                 handle->stats_op = usb_stats_linux;
 266                 handle->read_op = usb_read_linux;
 267         }
 268
 269         if (handle->opt.rfmon) {
 270                 /*
 271                  * Monitor mode doesn't apply to USB devices.
 272                  */
 273                 return PCAP_ERROR_RFMON_NOTSUP;
 274         }
 275
 276         /*
 277          * "handle->fd" is a real file, so "select()" and "poll()"
 278          * work on it.
 279          */
 280         handle->selectable_fd = handle->fd;
 281
 282         /* for plain binary access and text access we need to allocate the read
 283          * buffer */
 284         handle->buffer = malloc(handle->bufsize);
 285         if (!handle->buffer) {
 286                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 287                          "malloc: %s", pcap_strerror(errno));
 288                 return PCAP_ERROR;
 289         }
 290         return 0;
 291 }
 292
 293 static inline int
 294 ascii_to_int(char c)
 295 {
 296         return c < 'A' ? c- '0': ((c<'a') ? c - 'A' + 10: c-'a'+10);
 297 }
 298
 299 /*
 300  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 301  * <linux-kernel-source>/drivers/usb/mon/mon_text.c for urb string
 302  * format description
 303  */
 304 static int
 305 usb_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 306 {
 307         /* see:
 308         * /usr/src/linux/Documentation/usb/usbmon.txt
 309         * for message format
 310         */
 311         unsigned timestamp;
 312         int tag, cnt, ep_num, dev_addr, dummy, ret, urb_len, data_len;
 313         char etype, pipeid1, pipeid2, status[16], urb_tag, line[USB_LINE_LEN];
 314         char *string = line;
 315         u_char * rawdata = handle->buffer;
 316         struct pcap_pkthdr pkth;
 317         pcap_usb_header* uhdr = (pcap_usb_header*)handle->buffer;
 318         u_char urb_transfer=0;
 319         int incoming=0;
 320
 321         /* ignore interrupt system call errors */
 322         do {
 323                 ret = read(handle->fd, line, USB_LINE_LEN - 1);
 324                 if (handle->break_loop)
 325                 {
 326                         handle->break_loop = 0;
 327                         return -2;
 328                 }
 329         } while ((ret == -1) && (errno == EINTR));
 330         if (ret < 0)
 331         {
 332                 if (errno == EAGAIN)
 333                         return 0;       /* no data there */
 334
 335                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 336                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 337                 return -1;
 338         }
 339
 340         /* read urb header; %n argument may increment return value, but it's
 341         * not mandatory, so does not count on it*/
 342         string[ret] = 0;
 343         ret = sscanf(string, "%x %d %c %c%c:%d:%d %s%n", &tag, &timestamp, &etype,
 344                 &pipeid1, &pipeid2, &dev_addr, &ep_num, status,
 345                 &cnt);
 346         if (ret < 8)
 347         {
 348                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 349                     "Can't parse USB bus message '%s', too few tokens (expected 8 got %d)",
 350                     string, ret);
 351                 return -1;
 352         }
 353         uhdr->id = tag;
 354         uhdr->endpoint_number = ep_num;
 355         uhdr->device_address = dev_addr;
 356         uhdr->bus_id = handle->md.ifindex;
 357         uhdr->status = 0;
 358         string += cnt;
 359
 360         /* don't use usbmon provided timestamp, since it have low precision*/
 361         if (gettimeofday(&pkth.ts, NULL) < 0)
 362         {
 363                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 364                         "Can't get timestamp for message '%s' %d:%s",
 365                         string, errno, strerror(errno));
 366                 return -1;
 367         }
 368         uhdr->ts_sec = pkth.ts.tv_sec;
 369         uhdr->ts_usec = pkth.ts.tv_usec;
 370
 371         /* parse endpoint information */
 372         if (pipeid1 == 'C')
 373                 urb_transfer = URB_CONTROL;
 374         else if (pipeid1 == 'Z')
 375                 urb_transfer = URB_ISOCHRONOUS;
 376         else if (pipeid1 == 'I')
 377                 urb_transfer = URB_INTERRUPT;
 378         else if (pipeid1 == 'B')
 379                 urb_transfer = URB_BULK;
 380         if (pipeid2 == 'i') {
 381                 urb_transfer |= URB_TRANSFER_IN;
 382                 incoming = 1;
 383         }
 384         if (etype == 'C')
 385                 incoming = !incoming;
 386
 387         /* direction check*/
 388         if (incoming)
 389         {
 390                 if (handle->direction == PCAP_D_OUT)
 391                         return 0;
 392         }
 393         else
 394                 if (handle->direction == PCAP_D_IN)
 395                         return 0;
 396         uhdr->event_type = etype;
 397         uhdr->transfer_type = urb_transfer;
 398         pkth.caplen = sizeof(pcap_usb_header);
 399         rawdata += sizeof(pcap_usb_header);
 400
 401         /* check if this is a setup packet */
 402         ret = sscanf(status, "%d", &dummy);
 403         if (ret != 1)
 404         {
 405                 /* this a setup packet, setup data can be filled with underscore if
 406                 * usbmon has not been able to read them, so we must parse this fields as
 407                 * strings */
 408                 pcap_usb_setup* shdr;
 409                 char str1[3], str2[3], str3[5], str4[5], str5[5];
 410                 ret = sscanf(string, "%s %s %s %s %s%n", str1, str2, str3, str4,
 411                 str5, &cnt);
 412                 if (ret < 5)
 413                 {
 414                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 415                                 "Can't parse USB bus message '%s', too few tokens (expected 5 got %d)",
 416                                 string, ret);
 417                         return -1;
 418                 }
 419                 string += cnt;
 420
 421                 /* try to convert to corresponding integer */
 422                 shdr = &uhdr->setup;
 423                 shdr->bmRequestType = strtoul(str1, 0, 16);
 424                 shdr->bRequest = strtoul(str2, 0, 16);
 425                 shdr->wValue = htols(strtoul(str3, 0, 16));
 426                 shdr->wIndex = htols(strtoul(str4, 0, 16));
 427                 shdr->wLength = htols(strtoul(str5, 0, 16));
 428
 429                 uhdr->setup_flag = 0;
 430         }
 431         else
 432                 uhdr->setup_flag = 1;
 433
 434         /* read urb data */
 435         ret = sscanf(string, " %d%n", &urb_len, &cnt);
 436         if (ret < 1)
 437         {
 438                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 439                   "Can't parse urb length from '%s'", string);
 440                 return -1;
 441         }
 442         string += cnt;
 443
 444         /* urb tag is not present if urb length is 0, so we can stop here
 445          * text parsing */
 446         pkth.len = urb_len+pkth.caplen;
 447         uhdr->urb_len = urb_len;
 448         uhdr->data_flag = 1;
 449         data_len = 0;
 450         if (uhdr->urb_len == pkth.caplen)
 451                 goto got;
 452
 453         /* check for data presence; data is present if and only if urb tag is '=' */
 454         if (sscanf(string, " %c", &urb_tag) != 1)
 455         {
 456                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 457                         "Can't parse urb tag from '%s'", string);
 458                 return -1;
 459         }
 460
 461         if (urb_tag != '=')
 462                 goto got;
 463
 464         /* skip urb tag and following space */
 465         string += 3;
 466
 467         /* if we reach this point we got some urb data*/
 468         uhdr->data_flag = 0;
 469
 470         /* read all urb data; if urb length is greater then the usbmon internal
 471          * buffer length used by the kernel to spool the URB, we get only
 472          * a partial information.
 473          * At least until linux 2.6.17 there is no way to set usbmon intenal buffer
 474          * length and default value is 130. */
 475         while ((string[0] != 0) && (string[1] != 0) && (pkth.caplen < handle->snapshot))
 476         {
 477                 rawdata[0] = ascii_to_int(string[0]) * 16 + ascii_to_int(string[1]);
 478                 rawdata++;
 479                 string+=2;
 480                 if (string[0] == ' ')
 481                         string++;
 482                 pkth.caplen++;
 483                 data_len++;
 484         }
 485
 486 got:
 487         uhdr->data_len = data_len;
 488         handle->md.packets_read++;
 489         if (pkth.caplen > handle->snapshot)
 490                 pkth.caplen = handle->snapshot;
 491
 492         callback(user, &pkth, handle->buffer);
 493         return 1;
 494 }
 495
 496 static int
 497 usb_inject_linux(pcap_t *handle, const void *buf, size_t size)
 498 {
 499         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
 500                 "USB devices");
 501         return (-1);
 502 }
 503
 504 static int
 505 usb_stats_linux(pcap_t *handle, struct pcap_stat *stats)
 506 {
 507         int dummy, ret, consumed, cnt;
 508         char string[USB_LINE_LEN];
 509         char token[USB_LINE_LEN];
 510         char * ptr = string;
 511         snprintf(string, USB_LINE_LEN, USB_TEXT_DIR"/%ds", handle->md.ifindex);
 512
 513         int fd = open(string, O_RDONLY, 0);
 514         if (fd < 0)
 515         {
 516                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 517                         "Can't open USB stats file %s: %s",
 518                         string, strerror(errno));
 519                 return -1;
 520         }
 521
 522         /* read stats line */
 523         do {
 524                 ret = read(fd, string, USB_LINE_LEN-1);
 525         } while ((ret == -1) && (errno == EINTR));
 526         close(fd);
 527
 528         if (ret < 0)
 529         {
 530                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 531                         "Can't read stats from fd %d ", fd);
 532                 return -1;
 533         }
 534         string[ret] = 0;
 535
 536         /* extract info on dropped urbs */
 537         for (consumed=0; consumed < ret; ) {
 538                 /* from the sscanf man page:
 539                  * The C standard says: "Execution of a %n directive does
 540                  * not increment the assignment count returned at the completion
 541                  * of  execution" but the Corrigendum seems to contradict this.
 542                  * Do not make any assumptions on the effect of %n conversions
 543                  * on the return value and explicitly check for cnt assignmet*/
 544                 cnt = -1;
 545                 int ntok = sscanf(ptr, "%s%n", token, &cnt);
 546                 if ((ntok < 1) || (cnt < 0))
 547                         break;
 548                 consumed += cnt;
 549                 ptr += cnt;
 550                 if (strcmp(token, "nreaders") == 0)
 551                         ret = sscanf(ptr, "%d", &stats->ps_drop);
 552                 else
 553                         ret = sscanf(ptr, "%d", &dummy);
 554                 if (ntok != 1)
 555                         break;
 556                 consumed += cnt;
 557                 ptr += cnt;
 558         }
 559
 560         stats->ps_recv = handle->md.packets_read;
 561         stats->ps_ifdrop = 0;
 562         return 0;
 563 }
 564
 565 static int
 566 usb_setfilter_linux(pcap_t *p, struct bpf_program *fp)
 567 {
 568         return 0;
 569 }
 570
 571 static int
 572 usb_setdirection_linux(pcap_t *p, pcap_direction_t d)
 573 {
 574         p->direction = d;
 575         return 0;
 576 }
 577
 578
 579 static int
 580 usb_stats_linux_bin(pcap_t *handle, struct pcap_stat *stats)
 581 {
 582         int ret;
 583         struct mon_bin_stats st;
 584         ret = ioctl(handle->fd, MON_IOCG_STATS, &st);
 585         if (ret < 0)
 586         {
 587                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 588                         "Can't read stats from fd %d:%s ", handle->fd, strerror(errno));
 589                 return -1;
 590         }
 591
 592         stats->ps_recv = handle->md.packets_read + st.queued;
 593         stats->ps_ifdrop = st.dropped;
 594         return 0;
 595 }
 596
 597 /*
 598  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 599  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 600  */
 601 static int
 602 usb_read_linux_bin(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 603 {
 604         struct mon_bin_get info;
 605         int ret;
 606         struct pcap_pkthdr pkth;
 607         int clen = handle->snapshot - sizeof(pcap_usb_header);
 608
 609         /* the usb header is going to be part of 'packet' data*/
 610         info.hdr = (pcap_usb_header*) handle->buffer;
 611         info.data = handle->buffer + sizeof(pcap_usb_header);
 612         info.data_len = clen;
 613
 614         /* ignore interrupt system call errors */
 615         do {
 616                 ret = ioctl(handle->fd, MON_IOCX_GET, &info);
 617                 if (handle->break_loop)
 618                 {
 619                         handle->break_loop = 0;
 620                         return -2;
 621                 }
 622         } while ((ret == -1) && (errno == EINTR));
 623         if (ret < 0)
 624         {
 625                 if (errno == EAGAIN)
 626                         return 0;       /* no data there */
 627
 628                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 629                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 630                 return -1;
 631         }
 632
 633         /* we can get less that than really captured from kernel, depending on
 634          * snaplen, so adjust header accordingly */
 635         if (info.hdr->data_len < clen)
 636                 clen = info.hdr->data_len;
 637         info.hdr->data_len = clen;
 638         pkth.caplen = clen + sizeof(pcap_usb_header);
 639         pkth.len = info.hdr->urb_len + sizeof(pcap_usb_header);
 640         pkth.ts.tv_sec = info.hdr->ts_sec;
 641         pkth.ts.tv_usec = info.hdr->ts_usec;
 642
 643         handle->md.packets_read++;
 644         callback(user, &pkth, handle->buffer);
 645         return 1;
 646 }
 647
 648 /*
 649  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 650  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 651  */
 652 #define VEC_SIZE 32
 653 static int
 654 usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 655 {
 656         struct mon_bin_mfetch fetch;
 657         int32_t vec[VEC_SIZE];
 658         struct pcap_pkthdr pkth;
 659         pcap_usb_header* hdr;
 660         int nflush = 0;
 661         int packets = 0;
 662
 663         for (;;) {
 664                 int i, ret;
 665                 int limit = max_packets - packets;
 666                 if (limit <= 0)
 667                         limit = VEC_SIZE;
 668                 if (limit > VEC_SIZE)
 669                         limit = VEC_SIZE;
 670
 671                 /* try to fetch as many events as possible*/
 672                 fetch.offvec = vec;
 673                 fetch.nfetch = limit;
 674                 fetch.nflush = nflush;
 675                 /* ignore interrupt system call errors */
 676                 do {
 677                         ret = ioctl(handle->fd, MON_IOCX_MFETCH, &fetch);
 678                         if (handle->break_loop)
 679                         {
 680                                 handle->break_loop = 0;
 681                                 return -2;
 682                         }
 683                 } while ((ret == -1) && (errno == EINTR));
 684                 if (ret < 0)
 685                 {
 686                         if (errno == EAGAIN)
 687                                 return 0;       /* no data there */
 688
 689                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 690                             "Can't mfetch fd %d: %s", handle->fd, strerror(errno));
 691                         return -1;
 692                 }
 693
 694                 /* keep track of processed events, we will flush them later */
 695                 nflush = fetch.nfetch;
 696                 for (i=0; i<fetch.nfetch; ++i) {
 697                         /* discard filler */
 698                         hdr = (pcap_usb_header*) &handle->buffer[vec[i]];
 699                         if (hdr->event_type == '@')
 700                                 continue;
 701
 702                         /* get packet info from header*/
 703                         pkth.caplen = hdr->data_len + sizeof(pcap_usb_header);
 704                         pkth.len = hdr->urb_len + sizeof(pcap_usb_header);
 705                         pkth.ts.tv_sec = hdr->ts_sec;
 706                         pkth.ts.tv_usec = hdr->ts_usec;
 707
 708                         handle->md.packets_read++;
 709                         callback(user, &pkth, (u_char*) hdr);
 710                         packets++;
 711                 }
 712
 713                 /* with max_packets <= 0 we stop afer the first chunk*/
 714                 if ((max_packets <= 0) || (packets == max_packets))
 715                         break;
 716         }
 717
 718         /* flush pending events*/
 719         ioctl(handle->fd, MON_IOCH_MFLUSH, nflush);
 720         return packets;
 721 }
 722
 723 static void
 724 usb_cleanup_linux_mmap(pcap_t* handle)
 725 {
 726         /* buffer must not be freed because it's memory mapped */
 727         /* XXX - does it need to be unmapped? */
 728         handle->buffer = NULL;
 729         pcap_cleanup_live_common(handle);
 730 }