The Tcpdump Group git mirrors - libpcap/blob - pcap-usb-linux.c

   1 /*
   2  * Copyright (c) 1999 - 2005 NetGroup, Politecnico di Torino (Italy)
   3  * Copyright (c) 2005 - 2006 CACE Technologies, Davis (California)
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  * notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  * notice, this list of conditions and the following disclaimer in the
  14  * documentation and/or other materials provided with the distribution.
  15  * 3. Neither the name of the Politecnico di Torino, CACE Technologies
  16  * nor the names of its contributors may be used to endorse or promote
  17  * products derived from this software without specific prior written
  18  * permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  *
  32  * USB sniffing API implementation for Linux platform
  33  * By Paolo Abeni <paolo.abeni@email.it>
  34  *
  35  */
  36 #ifndef lint
  37 static const char rcsid[] _U_ =
  38     "@(#) $Header: /tcpdump/master/libpcap/pcap-usb-linux.c,v 1.15 2007-04-01 21:43:55 guy Exp $ (LBL)";
  39 #endif
  40
  41 #ifdef HAVE_CONFIG_H
  42 #include "config.h"
  43 #endif
  44
  45 #include "pcap-int.h"
  46 #include "pcap-usb-linux.h"
  47 #include "pcap/usb.h"
  48
  49 #ifdef NEED_STRERROR_H
  50 #include "strerror.h"
  51 #endif
  52
  53 #include <ctype.h>
  54 #include <errno.h>
  55 #include <stdlib.h>
  56 #include <unistd.h>
  57 #include <fcntl.h>
  58 #include <string.h>
  59 #include <dirent.h>
  60 #include <byteswap.h>
  61 #include <netinet/in.h>
  62 #include <sys/ioctl.h>
  63 #include <sys/mman.h>
  64
  65 #define USB_IFACE "usb"
  66 #define USB_TEXT_DIR "/sys/kernel/debug/usbmon"
  67 #define USB_BUS_DIR "/proc/bus/usb"
  68 #define USB_LINE_LEN 4096
  69
  70
  71 #define PIPE_IN                 0x80
  72 #define PIPE_ISOCHRONOUS        0
  73 #define PIPE_INTERRUPT          1
  74 #define PIPE_CONTROL            2
  75 #define PIPE_BULK               3
  76
  77 #if __BYTE_ORDER == __LITTLE_ENDIAN
  78 #define htols(s) s
  79 #define htoll(l) l
  80 #define htol64(ll) ll
  81 #else
  82 #define htols(s) bswap_16(s)
  83 #define htoll(l) bswap_32(l)
  84 #define htol64(ll) bswap_64(ll)
  85 #endif
  86
  87 struct mon_bin_stats {
  88         u_int32_t queued;
  89         u_int32_t dropped;
  90 };
  91
  92 struct mon_bin_get {
  93         pcap_usb_header *hdr;
  94         void *data;
  95         size_t data_len;   /* Length of data (can be zero) */
  96 };
  97
  98 struct mon_bin_mfetch {
  99         int32_t *offvec;   /* Vector of events fetched */
 100         int32_t nfetch;    /* Number of events to fetch (out: fetched) */
 101         int32_t nflush;    /* Number of events to flush */
 102 };
 103
 104 #define MON_IOC_MAGIC 0x92
 105
 106 #define MON_IOCQ_URB_LEN _IO(MON_IOC_MAGIC, 1)
 107 #define MON_IOCX_URB  _IOWR(MON_IOC_MAGIC, 2, struct mon_bin_hdr)
 108 #define MON_IOCG_STATS _IOR(MON_IOC_MAGIC, 3, struct mon_bin_stats)
 109 #define MON_IOCT_RING_SIZE _IO(MON_IOC_MAGIC, 4)
 110 #define MON_IOCQ_RING_SIZE _IO(MON_IOC_MAGIC, 5)
 111 #define MON_IOCX_GET   _IOW(MON_IOC_MAGIC, 6, struct mon_bin_get)
 112 #define MON_IOCX_MFETCH _IOWR(MON_IOC_MAGIC, 7, struct mon_bin_mfetch)
 113 #define MON_IOCH_MFLUSH _IO(MON_IOC_MAGIC, 8)
 114
 115 #define MON_BIN_SETUP   0x1 /* setup hdr is present*/
 116 #define MON_BIN_SETUP_ZERO      0x2 /* setup buffer is not available */
 117 #define MON_BIN_DATA_ZERO       0x4 /* data buffer is not available */
 118 #define MON_BIN_ERROR   0x8
 119
 120 /* forward declaration */
 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_close_linux(pcap_t *);
 130 static void usb_close_linux_mmap(pcap_t *);
 131
 132 /* facility to add an USB device to the device list*/
 133 static int
 134 usb_dev_add(pcap_if_t** alldevsp, int n, char *err_str)
 135 {
 136         char dev_name[10];
 137         char dev_descr[30];
 138         snprintf(dev_name, 10, USB_IFACE"%d", n);
 139         snprintf(dev_descr, 30, "USB bus number %d", n);
 140
 141         if (pcap_add_if(alldevsp, dev_name, 0,
 142             dev_descr, err_str) < 0)
 143                 return -1;
 144         return 0;
 145 }
 146
 147 int
 148 usb_platform_finddevs(pcap_if_t **alldevsp, char *err_str)
 149 {
 150         struct dirent* data;
 151         int ret = 0;
 152         DIR* dir;
 153
 154         /* scan profs usb bus directorys */
 155         dir = opendir(USB_BUS_DIR);
 156         if (!dir) return 0;
 157         while ((ret == 0) && ((data = readdir(dir)) != 0)) {
 158                 int n;
 159                 char* name = data->d_name;
 160                 int len = strlen(name);
 161
 162                 /* if this file name does not end with a number it's not of our interest */
 163                 if ((len < 1) || !isdigit(name[--len]))
 164                         continue;
 165                 while (isdigit(name[--len]));
 166                 if (sscanf(&name[len+1], "%d", &n) != 1)
 167                         continue;
 168
 169                 ret = usb_dev_add(alldevsp, n, err_str);
 170         }
 171
 172         closedir(dir);
 173         return ret;
 174 }
 175
 176 static
 177 int usb_mmap(pcap_t* handle)
 178 {
 179         int len = ioctl(handle->fd, MON_IOCQ_RING_SIZE);
 180         if (len < 0)
 181                 return 0;
 182
 183         handle->buffer = mmap(0, len, PROT_READ, MAP_SHARED, handle->fd, 0);
 184         return handle->buffer != MAP_FAILED;
 185 }
 186
 187 pcap_t*
 188 usb_open_live(const char* bus, int snaplen, int promisc , int to_ms, char* errmsg)
 189 {
 190         char            full_path[USB_LINE_LEN];
 191         pcap_t          *handle;
 192
 193         /* Allocate a handle for this session. */
 194         handle = malloc(sizeof(*handle));
 195         if (handle == NULL) {
 196                 snprintf(errmsg, PCAP_ERRBUF_SIZE, "malloc: %s",
 197                         pcap_strerror(errno));
 198                 return NULL;
 199         }
 200
 201         /* Initialize some components of the pcap structure. */
 202         memset(handle, 0, sizeof(*handle));
 203         handle->snapshot        = snaplen;
 204         handle->md.timeout      = to_ms;
 205         handle->bufsize = snaplen;
 206         handle->offset = 0;
 207         handle->linktype = DLT_USB_LINUX;
 208
 209         /*
 210          * "handle->fd" is a real file , so "select()" and "poll()"
 211          * work on it.
 212          */
 213         handle->selectable_fd = handle->fd;
 214
 215         handle->inject_op = usb_inject_linux;
 216         handle->setfilter_op = usb_setfilter_linux;
 217         handle->setdirection_op = usb_setdirection_linux;
 218         handle->set_datalink_op = NULL; /* can't change data link type */
 219         handle->getnonblock_op = pcap_getnonblock_fd;
 220         handle->setnonblock_op = pcap_setnonblock_fd;
 221         handle->close_op = usb_close_linux;
 222
 223         /*get usb bus index from device name */
 224         if (sscanf(bus, USB_IFACE"%d", &handle->md.ifindex) != 1)
 225         {
 226                 snprintf(errmsg, PCAP_ERRBUF_SIZE,
 227                         "Can't get USB bus index from %s", bus);
 228                 free(handle);
 229                 return NULL;
 230         }
 231
 232         /*now select the read method: try to open binary interface */
 233         snprintf(full_path, USB_LINE_LEN, LINUX_USB_MON_DEV"%d", handle->md.ifindex);
 234         handle->fd = open(full_path, O_RDONLY, 0);
 235         if (handle->fd >= 0)
 236         {
 237                 /* header endianess can't be fixed for memory mapped access,
 238                  * due to read only access to mmaped buffer, so disable it*/
 239                 /* binary api is available, try to use fast mmap access */
 240                 if (usb_mmap(handle)) {
 241                         handle->stats_op = usb_stats_linux_bin;
 242                         handle->read_op = usb_read_linux_mmap;
 243                         handle->close_op = usb_close_linux_mmap;
 244                         return handle;
 245                 }
 246
 247                 /* can't mmap, use plain binary interface access */
 248                 handle->stats_op = usb_stats_linux_bin;
 249                 handle->read_op = usb_read_linux_bin;
 250         }
 251         else {
 252                 /*Binary interface not available, try open text interface */
 253                 snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR"/%dt", handle->md.ifindex);
 254                 handle->fd = open(full_path, O_RDONLY, 0);
 255                 if (handle->fd < 0)
 256                 {
 257                         /* no more fallback, give it up*/
 258                         snprintf(errmsg, PCAP_ERRBUF_SIZE,
 259                                 "Can't open USB bus file %s: %s", full_path, strerror(errno));
 260                         free(handle);
 261                         return NULL;
 262                 }
 263                 handle->stats_op = usb_stats_linux;
 264                 handle->read_op = usb_read_linux;
 265         }
 266
 267         /* for plain binary access and text access we need to allocate the read
 268          * buffer */
 269         handle->buffer = malloc(handle->bufsize);
 270         if (!handle->buffer) {
 271                 snprintf(errmsg, PCAP_ERRBUF_SIZE,
 272                          "malloc: %s", pcap_strerror(errno));
 273                 usb_close_linux(handle);
 274                 return NULL;
 275         }
 276         return handle;
 277 }
 278
 279 static inline int
 280 ascii_to_int(char c)
 281 {
 282         return c < 'A' ? c- '0': ((c<'a') ? c - 'A' + 10: c-'a'+10);
 283 }
 284
 285 /*
 286  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 287  * <linux-kernel-source>/drivers/usb/mon/mon_text.c for urb string
 288  * format description
 289  */
 290 static int
 291 usb_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 292 {
 293         /* see:
 294         * /usr/src/linux/Documentation/usb/usbmon.txt
 295         * for message format
 296         */
 297         unsigned timestamp;
 298         int tag, cnt, ep_num, dev_addr, dummy, ret, urb_len, data_len;
 299         char etype, pipeid1, pipeid2, status[16], urb_tag, line[USB_LINE_LEN];
 300         char *string = line;
 301         u_char * rawdata = handle->buffer;
 302         struct pcap_pkthdr pkth;
 303         pcap_usb_header* uhdr = (pcap_usb_header*)handle->buffer;
 304         u_char urb_transfer=0;
 305         int incoming=0;
 306
 307         /* ignore interrupt system call errors */
 308         do {
 309                 ret = read(handle->fd, line, USB_LINE_LEN - 1);
 310                 if (handle->break_loop)
 311                 {
 312                         handle->break_loop = 0;
 313                         return -2;
 314                 }
 315         } while ((ret == -1) && (errno == EINTR));
 316         if (ret < 0)
 317         {
 318                 if (errno == EAGAIN)
 319                         return 0;       /* no data there */
 320
 321                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 322                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 323                 return -1;
 324         }
 325
 326         /* read urb header; %n argument may increment return value, but it's
 327         * not mandatory, so does not count on it*/
 328         string[ret] = 0;
 329         ret = sscanf(string, "%x %d %c %c%c:%d:%d %s%n", &tag, &timestamp, &etype,
 330                 &pipeid1, &pipeid2, &dev_addr, &ep_num, status,
 331                 &cnt);
 332         if (ret < 8)
 333         {
 334                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 335                     "Can't parse USB bus message '%s', too few tokens (expected 8 got %d)",
 336                     string, ret);
 337                 return -1;
 338         }
 339         uhdr->id = tag;
 340         uhdr->endpoint_number = ep_num;
 341         uhdr->device_address = dev_addr;
 342         uhdr->bus_id = handle->md.ifindex;
 343         uhdr->status = 0;
 344         string += cnt;
 345
 346         /* don't use usbmon provided timestamp, since it have low precision*/
 347         if (gettimeofday(&pkth.ts, NULL) < 0)
 348         {
 349                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 350                         "Can't get timestamp for message '%s' %d:%s",
 351                         string, errno, strerror(errno));
 352                 return -1;
 353         }
 354         uhdr->ts_sec = pkth.ts.tv_sec;
 355         uhdr->ts_usec = pkth.ts.tv_usec;
 356
 357         /* parse endpoint information */
 358         if (pipeid1 == 'C')
 359                 urb_transfer = URB_CONTROL;
 360         else if (pipeid1 == 'Z')
 361                 urb_transfer = URB_ISOCHRONOUS;
 362         else if (pipeid1 == 'I')
 363                 urb_transfer = URB_INTERRUPT;
 364         else if (pipeid1 == 'B')
 365                 urb_transfer = URB_BULK;
 366         if (pipeid2 == 'i') {
 367                 urb_transfer |= URB_TRANSFER_IN;
 368                 incoming = 1;
 369         }
 370         if (etype == 'C')
 371                 incoming = !incoming;
 372
 373         /* direction check*/
 374         if (incoming)
 375         {
 376                 if (handle->direction == PCAP_D_OUT)
 377                         return 0;
 378         }
 379         else
 380                 if (handle->direction == PCAP_D_IN)
 381                         return 0;
 382         uhdr->event_type = etype;
 383         uhdr->transfer_type = urb_transfer;
 384         pkth.caplen = sizeof(pcap_usb_header);
 385         rawdata += sizeof(pcap_usb_header);
 386
 387         /* check if this is a setup packet */
 388         ret = sscanf(status, "%d", &dummy);
 389         if (ret != 1)
 390         {
 391                 /* this a setup packet, setup data can be filled with underscore if
 392                 * usbmon has not been able to read them, so we must parse this fields as
 393                 * strings */
 394                 pcap_usb_setup* shdr;
 395                 char str1[3], str2[3], str3[5], str4[5], str5[5];
 396                 ret = sscanf(string, "%s %s %s %s %s%n", str1, str2, str3, str4,
 397                 str5, &cnt);
 398                 if (ret < 5)
 399                 {
 400                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 401                                 "Can't parse USB bus message '%s', too few tokens (expected 5 got %d)",
 402                                 string, ret);
 403                         return -1;
 404                 }
 405                 string += cnt;
 406
 407                 /* try to convert to corresponding integer */
 408                 shdr = &uhdr->setup;
 409                 shdr->bmRequestType = strtoul(str1, 0, 16);
 410                 shdr->bRequest = strtoul(str2, 0, 16);
 411                 shdr->wValue = htols(strtoul(str3, 0, 16));
 412                 shdr->wIndex = htols(strtoul(str4, 0, 16));
 413                 shdr->wLength = htols(strtoul(str5, 0, 16));
 414
 415                 uhdr->setup_flag = 0;
 416         }
 417         else
 418                 uhdr->setup_flag = 1;
 419
 420         /* read urb data */
 421         ret = sscanf(string, " %d%n", &urb_len, &cnt);
 422         if (ret < 1)
 423         {
 424                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 425                   "Can't parse urb length from '%s'", string);
 426                 return -1;
 427         }
 428         string += cnt;
 429
 430         /* urb tag is not present if urb length is 0, so we can stop here
 431          * text parsing */
 432         pkth.len = urb_len+pkth.caplen;
 433         uhdr->urb_len = urb_len;
 434         uhdr->data_flag = 1;
 435         data_len = 0;
 436         if (uhdr->urb_len == pkth.caplen)
 437                 goto got;
 438
 439         /* check for data presence; data is present if and only if urb tag is '=' */
 440         if (sscanf(string, " %c", &urb_tag) != 1)
 441         {
 442                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 443                         "Can't parse urb tag from '%s'", string);
 444                 return -1;
 445         }
 446
 447         if (urb_tag != '=')
 448                 goto got;
 449
 450         /* skip urb tag and following space */
 451         string += 3;
 452
 453         /* if we reach this point we got some urb data*/
 454         uhdr->data_flag = 0;
 455
 456         /* read all urb data; if urb length is greater then the usbmon internal
 457          * buffer length used by the kernel to spool the URB, we get only
 458          * a partial information.
 459          * At least until linux 2.6.17 there is no way to set usbmon intenal buffer
 460          * length and default value is 130. */
 461         while ((string[0] != 0) && (string[1] != 0) && (pkth.caplen < handle->snapshot))
 462         {
 463                 rawdata[0] = ascii_to_int(string[0]) * 16 + ascii_to_int(string[1]);
 464                 rawdata++;
 465                 string+=2;
 466                 if (string[0] == ' ')
 467                         string++;
 468                 pkth.caplen++;
 469                 data_len++;
 470         }
 471
 472 got:
 473         uhdr->data_len = data_len;
 474         handle->md.packets_read++;
 475         if (pkth.caplen > handle->snapshot)
 476                 pkth.caplen = handle->snapshot;
 477
 478         callback(user, &pkth, handle->buffer);
 479         return 1;
 480 }
 481
 482 static int
 483 usb_inject_linux(pcap_t *handle, const void *buf, size_t size)
 484 {
 485         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
 486                 "USB devices");
 487         return (-1);
 488 }
 489
 490 static void
 491 usb_close_linux(pcap_t* handle)
 492 {
 493         /* handle fill be freed in pcap_close() 'common' code */
 494         close(handle->fd);
 495         if (handle->buffer)
 496                 free(handle->buffer);
 497 }
 498
 499 static int
 500 usb_stats_linux(pcap_t *handle, struct pcap_stat *stats)
 501 {
 502         int dummy, ret, consumed, cnt;
 503         char string[USB_LINE_LEN];
 504         char token[USB_LINE_LEN];
 505         char * ptr = string;
 506         snprintf(string, USB_LINE_LEN, USB_TEXT_DIR"/%ds", handle->md.ifindex);
 507
 508         int fd = open(string, O_RDONLY, 0);
 509         if (fd < 0)
 510         {
 511                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 512                         "Can't open USB stats file %s: %s",
 513                         string, strerror(errno));
 514                 return -1;
 515         }
 516
 517         /* read stats line */
 518         do {
 519                 ret = read(fd, string, USB_LINE_LEN-1);
 520         } while ((ret == -1) && (errno == EINTR));
 521         close(fd);
 522
 523         if (ret < 0)
 524         {
 525                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 526                         "Can't read stats from fd %d ", fd);
 527                 return -1;
 528         }
 529         string[ret] = 0;
 530
 531         /* extract info on dropped urbs */
 532         for (consumed=0; consumed < ret; ) {
 533                 int ntok = sscanf(ptr, "%s%n", token, &cnt);
 534                 if (ntok != 2)
 535                         break;
 536                 consumed += cnt;
 537                 ptr += cnt;
 538                 if (strcmp(token, "nreaders") == 0)
 539                         ret = sscanf(ptr, "%d", &stats->ps_drop);
 540                 else
 541                         ret = sscanf(ptr, "%d", &dummy);
 542                 if (ntok != 2)
 543                         break;
 544                 consumed += cnt;
 545                 ptr += cnt;
 546         }
 547
 548         stats->ps_recv = handle->md.packets_read;
 549         stats->ps_ifdrop = 0;
 550         return 0;
 551 }
 552
 553 static int
 554 usb_setfilter_linux(pcap_t *p, struct bpf_program *fp)
 555 {
 556         return 0;
 557 }
 558
 559 static int
 560 usb_setdirection_linux(pcap_t *p, pcap_direction_t d)
 561 {
 562         p->direction = d;
 563         return 0;
 564 }
 565
 566
 567 static int
 568 usb_stats_linux_bin(pcap_t *handle, struct pcap_stat *stats)
 569 {
 570         int ret;
 571         struct mon_bin_stats st;
 572         ret = ioctl(handle->fd, MON_IOCG_STATS, &st);
 573         if (ret < 0)
 574         {
 575                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 576                         "Can't read stats from fd %d:%s ", handle->fd, strerror(errno));
 577                 return -1;
 578         }
 579
 580         stats->ps_recv = handle->md.packets_read + st.queued;
 581         stats->ps_ifdrop = st.dropped;
 582         return 0;
 583 }
 584
 585 /*
 586  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 587  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 588  */
 589 static int
 590 usb_read_linux_bin(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 591 {
 592         struct mon_bin_get info;
 593         int ret;
 594         struct pcap_pkthdr pkth;
 595         int clen = handle->snapshot - sizeof(pcap_usb_header);
 596
 597         /* the usb header is going to be part of 'packet' data*/
 598         info.hdr = (pcap_usb_header*) handle->buffer;
 599         info.data = handle->buffer + sizeof(pcap_usb_header);
 600         info.data_len = clen;
 601         /* ignore interrupt system call errors */
 602         do {
 603                 ret = ioctl(handle->fd, MON_IOCX_GET, &info);
 604                 if (handle->break_loop)
 605                 {
 606                         handle->break_loop = 0;
 607                         return -2;
 608                 }
 609         } while ((ret == -1) && (errno == EINTR));
 610         if (ret < 0)
 611         {
 612                 if (errno == EAGAIN)
 613                         return 0;       /* no data there */
 614
 615                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 616                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 617                 return -1;
 618         }
 619
 620         /* we can get less that than really captured from kernel, depending on
 621          * snaplen, so adjust header accordingly */
 622         if (info.hdr->data_len < clen)
 623                 clen = info.hdr->data_len;
 624         info.hdr->data_len = clen;
 625         pkth.caplen = clen + sizeof(pcap_usb_header);
 626         pkth.len = info.hdr->urb_len + sizeof(pcap_usb_header);
 627         pkth.ts.tv_sec = info.hdr->ts_sec;
 628         pkth.ts.tv_usec = info.hdr->ts_usec;
 629
 630         handle->md.packets_read++;
 631         callback(user, &pkth, handle->buffer);
 632         return 1;
 633 }
 634
 635 /*
 636  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 637  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 638  */
 639 #define VEC_SIZE 32
 640 static int
 641 usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 642 {
 643         struct mon_bin_mfetch fetch;
 644         int32_t vec[VEC_SIZE];
 645         struct pcap_pkthdr pkth;
 646         pcap_usb_header* hdr;
 647         int nflush = 0;
 648         int packets = 0;
 649
 650         for (;;) {
 651                 int i, ret;
 652                 int limit = max_packets - packets;
 653                 if (limit < 0)
 654                         limit = VEC_SIZE;
 655                 if (limit > VEC_SIZE)
 656                         limit = VEC_SIZE;
 657
 658                 /* try to fetch as many events as possible*/
 659                 fetch.offvec = vec;
 660                 fetch.nfetch = limit;
 661                 fetch.nflush = nflush;
 662                 /* ignore interrupt system call errors */
 663                 do {
 664                         ret = ioctl(handle->fd, MON_IOCX_MFETCH, &fetch);
 665                         if (handle->break_loop)
 666                         {
 667                                 handle->break_loop = 0;
 668                                 return -2;
 669                         }
 670                 } while ((ret == -1) && (errno == EINTR));
 671                 if (ret < 0)
 672                 {
 673                         if (errno == EAGAIN)
 674                                 return 0;       /* no data there */
 675
 676                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 677                             "Can't mfetch fd %d: %s", handle->fd, strerror(errno));
 678                         return -1;
 679                 }
 680
 681                 /* keep track of processed events, we will flush them later */
 682                 nflush = fetch.nfetch;
 683                 for (i=0; i<fetch.nfetch; ++i) {
 684                         /* discard filler */
 685                         hdr = (pcap_usb_header*) &handle->buffer[vec[i]];
 686                         if (hdr->event_type == '@')
 687                                 continue;
 688
 689                         /* get packet info from header*/
 690                         pkth.caplen = hdr->data_len + sizeof(pcap_usb_header);
 691                         pkth.len = hdr->urb_len + sizeof(pcap_usb_header);
 692                         pkth.ts.tv_sec = hdr->ts_sec;
 693                         pkth.ts.tv_usec = hdr->ts_usec;
 694
 695                         handle->md.packets_read++;
 696                         callback(user, &pkth, (u_char*) hdr);
 697                         packets++;
 698                 }
 699
 700                 /* with max_packets == -1 we stop afer the first chunk*/
 701                 if ((max_packets == -1) || (packets == max_packets))
 702                         break;
 703         }
 704
 705         /* flush pending events*/
 706         ioctl(handle->fd, MON_IOCH_MFLUSH, nflush);
 707         return packets;
 708 }
 709
 710 static void
 711 usb_close_linux_mmap(pcap_t* handle)
 712 {
 713         /* handle fill be freed in pcap_close() 'common' code, buffer must not
 714          * be freed because it's memory mapped */
 715         close(handle->fd);
 716 }