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

   1 /*
   2  * Copyright (c) 2006 Paolo Abeni (Italy)
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote
  15  * products derived from this software without specific prior written
  16  * permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  *
  30  * USB sniffing API implementation for Linux platform
  31  * By Paolo Abeni <paolo.abeni@email.it>
  32  * Modifications: Kris Katterjohn <katterjohn@gmail.com>
  33  *
  34  */
  35 #ifndef lint
  36 static const char rcsid[] _U_ =
  37     "@(#) $Header: /tcpdump/master/libpcap/pcap-usb-linux.c,v 1.16.2.6 2008-04-04 19:39:06 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_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 procfs usb bus directory */
 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_create(const char *device, char *ebuf)
 189 {
 190         pcap_t *p;
 191
 192         p = pcap_create_common(device, ebuf);
 193         if (p == NULL)
 194                 return (NULL);
 195
 196         p->activate_op = usb_activate;
 197         return (p);
 198 }
 199
 200 static int
 201 usb_activate(pcap_t* handle)
 202 {
 203         char            full_path[USB_LINE_LEN];
 204
 205         /* Initialize some components of the pcap structure. */
 206         handle->bufsize = handle->snapshot;
 207         handle->offset = 0;
 208         handle->linktype = DLT_USB_LINUX;
 209
 210         handle->inject_op = usb_inject_linux;
 211         handle->setfilter_op = usb_setfilter_linux;
 212         handle->setdirection_op = usb_setdirection_linux;
 213         handle->set_datalink_op = NULL; /* can't change data link type */
 214         handle->getnonblock_op = pcap_getnonblock_fd;
 215         handle->setnonblock_op = pcap_setnonblock_fd;
 216         handle->close_op = usb_close_linux;
 217
 218         /*get usb bus index from device name */
 219         if (sscanf(handle->opt.source, USB_IFACE"%d", &handle->md.ifindex) != 1)
 220         {
 221                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 222                         "Can't get USB bus index from %s", handle->opt.source);
 223                 return -1;
 224         }
 225
 226         /*now select the read method: try to open binary interface */
 227         snprintf(full_path, USB_LINE_LEN, LINUX_USB_MON_DEV"%d", handle->md.ifindex);
 228         handle->fd = open(full_path, O_RDONLY, 0);
 229         if (handle->fd >= 0)
 230         {
 231                 /* binary api is available, try to use fast mmap access */
 232                 if (usb_mmap(handle)) {
 233                         handle->stats_op = usb_stats_linux_bin;
 234                         handle->read_op = usb_read_linux_mmap;
 235                         handle->close_op = usb_close_linux_mmap;
 236
 237                         /*
 238                          * "handle->fd" is a real file, so "select()" and
 239                          * "poll()" work on it.
 240                          */
 241                         handle->selectable_fd = handle->fd;
 242                         return 0;
 243                 }
 244
 245                 /* can't mmap, use plain binary interface access */
 246                 handle->stats_op = usb_stats_linux_bin;
 247                 handle->read_op = usb_read_linux_bin;
 248         }
 249         else {
 250                 /*Binary interface not available, try open text interface */
 251                 snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR"/%dt", handle->md.ifindex);
 252                 handle->fd = open(full_path, O_RDONLY, 0);
 253                 if (handle->fd < 0)
 254                 {
 255                         /* no more fallback, give it up*/
 256                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 257                                 "Can't open USB bus file %s: %s", full_path, strerror(errno));
 258                         return -1;
 259                 }
 260                 handle->stats_op = usb_stats_linux;
 261                 handle->read_op = usb_read_linux;
 262         }
 263
 264         /*
 265          * "handle->fd" is a real file, so "select()" and "poll()"
 266          * work on it.
 267          */
 268         handle->selectable_fd = handle->fd;
 269
 270         /* for plain binary access and text access we need to allocate the read
 271          * buffer */
 272         handle->buffer = malloc(handle->bufsize);
 273         if (!handle->buffer) {
 274                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 275                          "malloc: %s", pcap_strerror(errno));
 276                 close(handle->fd);
 277                 return -1;
 278         }
 279         return 0;
 280 }
 281
 282 static inline int
 283 ascii_to_int(char c)
 284 {
 285         return c < 'A' ? c- '0': ((c<'a') ? c - 'A' + 10: c-'a'+10);
 286 }
 287
 288 /*
 289  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 290  * <linux-kernel-source>/drivers/usb/mon/mon_text.c for urb string
 291  * format description
 292  */
 293 static int
 294 usb_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 295 {
 296         /* see:
 297         * /usr/src/linux/Documentation/usb/usbmon.txt
 298         * for message format
 299         */
 300         unsigned timestamp;
 301         int tag, cnt, ep_num, dev_addr, dummy, ret, urb_len, data_len;
 302         char etype, pipeid1, pipeid2, status[16], urb_tag, line[USB_LINE_LEN];
 303         char *string = line;
 304         u_char * rawdata = handle->buffer;
 305         struct pcap_pkthdr pkth;
 306         pcap_usb_header* uhdr = (pcap_usb_header*)handle->buffer;
 307         u_char urb_transfer=0;
 308         int incoming=0;
 309
 310         /* ignore interrupt system call errors */
 311         do {
 312                 ret = read(handle->fd, line, USB_LINE_LEN - 1);
 313                 if (handle->break_loop)
 314                 {
 315                         handle->break_loop = 0;
 316                         return -2;
 317                 }
 318         } while ((ret == -1) && (errno == EINTR));
 319         if (ret < 0)
 320         {
 321                 if (errno == EAGAIN)
 322                         return 0;       /* no data there */
 323
 324                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 325                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 326                 return -1;
 327         }
 328
 329         /* read urb header; %n argument may increment return value, but it's
 330         * not mandatory, so does not count on it*/
 331         string[ret] = 0;
 332         ret = sscanf(string, "%x %d %c %c%c:%d:%d %s%n", &tag, &timestamp, &etype,
 333                 &pipeid1, &pipeid2, &dev_addr, &ep_num, status,
 334                 &cnt);
 335         if (ret < 8)
 336         {
 337                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 338                     "Can't parse USB bus message '%s', too few tokens (expected 8 got %d)",
 339                     string, ret);
 340                 return -1;
 341         }
 342         uhdr->id = tag;
 343         uhdr->endpoint_number = ep_num;
 344         uhdr->device_address = dev_addr;
 345         uhdr->bus_id = handle->md.ifindex;
 346         uhdr->status = 0;
 347         string += cnt;
 348
 349         /* don't use usbmon provided timestamp, since it have low precision*/
 350         if (gettimeofday(&pkth.ts, NULL) < 0)
 351         {
 352                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 353                         "Can't get timestamp for message '%s' %d:%s",
 354                         string, errno, strerror(errno));
 355                 return -1;
 356         }
 357         uhdr->ts_sec = pkth.ts.tv_sec;
 358         uhdr->ts_usec = pkth.ts.tv_usec;
 359
 360         /* parse endpoint information */
 361         if (pipeid1 == 'C')
 362                 urb_transfer = URB_CONTROL;
 363         else if (pipeid1 == 'Z')
 364                 urb_transfer = URB_ISOCHRONOUS;
 365         else if (pipeid1 == 'I')
 366                 urb_transfer = URB_INTERRUPT;
 367         else if (pipeid1 == 'B')
 368                 urb_transfer = URB_BULK;
 369         if (pipeid2 == 'i') {
 370                 urb_transfer |= URB_TRANSFER_IN;
 371                 incoming = 1;
 372         }
 373         if (etype == 'C')
 374                 incoming = !incoming;
 375
 376         /* direction check*/
 377         if (incoming)
 378         {
 379                 if (handle->direction == PCAP_D_OUT)
 380                         return 0;
 381         }
 382         else
 383                 if (handle->direction == PCAP_D_IN)
 384                         return 0;
 385         uhdr->event_type = etype;
 386         uhdr->transfer_type = urb_transfer;
 387         pkth.caplen = sizeof(pcap_usb_header);
 388         rawdata += sizeof(pcap_usb_header);
 389
 390         /* check if this is a setup packet */
 391         ret = sscanf(status, "%d", &dummy);
 392         if (ret != 1)
 393         {
 394                 /* this a setup packet, setup data can be filled with underscore if
 395                 * usbmon has not been able to read them, so we must parse this fields as
 396                 * strings */
 397                 pcap_usb_setup* shdr;
 398                 char str1[3], str2[3], str3[5], str4[5], str5[5];
 399                 ret = sscanf(string, "%s %s %s %s %s%n", str1, str2, str3, str4,
 400                 str5, &cnt);
 401                 if (ret < 5)
 402                 {
 403                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 404                                 "Can't parse USB bus message '%s', too few tokens (expected 5 got %d)",
 405                                 string, ret);
 406                         return -1;
 407                 }
 408                 string += cnt;
 409
 410                 /* try to convert to corresponding integer */
 411                 shdr = &uhdr->setup;
 412                 shdr->bmRequestType = strtoul(str1, 0, 16);
 413                 shdr->bRequest = strtoul(str2, 0, 16);
 414                 shdr->wValue = htols(strtoul(str3, 0, 16));
 415                 shdr->wIndex = htols(strtoul(str4, 0, 16));
 416                 shdr->wLength = htols(strtoul(str5, 0, 16));
 417
 418                 uhdr->setup_flag = 0;
 419         }
 420         else
 421                 uhdr->setup_flag = 1;
 422
 423         /* read urb data */
 424         ret = sscanf(string, " %d%n", &urb_len, &cnt);
 425         if (ret < 1)
 426         {
 427                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 428                   "Can't parse urb length from '%s'", string);
 429                 return -1;
 430         }
 431         string += cnt;
 432
 433         /* urb tag is not present if urb length is 0, so we can stop here
 434          * text parsing */
 435         pkth.len = urb_len+pkth.caplen;
 436         uhdr->urb_len = urb_len;
 437         uhdr->data_flag = 1;
 438         data_len = 0;
 439         if (uhdr->urb_len == pkth.caplen)
 440                 goto got;
 441
 442         /* check for data presence; data is present if and only if urb tag is '=' */
 443         if (sscanf(string, " %c", &urb_tag) != 1)
 444         {
 445                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 446                         "Can't parse urb tag from '%s'", string);
 447                 return -1;
 448         }
 449
 450         if (urb_tag != '=')
 451                 goto got;
 452
 453         /* skip urb tag and following space */
 454         string += 3;
 455
 456         /* if we reach this point we got some urb data*/
 457         uhdr->data_flag = 0;
 458
 459         /* read all urb data; if urb length is greater then the usbmon internal
 460          * buffer length used by the kernel to spool the URB, we get only
 461          * a partial information.
 462          * At least until linux 2.6.17 there is no way to set usbmon intenal buffer
 463          * length and default value is 130. */
 464         while ((string[0] != 0) && (string[1] != 0) && (pkth.caplen < handle->snapshot))
 465         {
 466                 rawdata[0] = ascii_to_int(string[0]) * 16 + ascii_to_int(string[1]);
 467                 rawdata++;
 468                 string+=2;
 469                 if (string[0] == ' ')
 470                         string++;
 471                 pkth.caplen++;
 472                 data_len++;
 473         }
 474
 475 got:
 476         uhdr->data_len = data_len;
 477         handle->md.packets_read++;
 478         if (pkth.caplen > handle->snapshot)
 479                 pkth.caplen = handle->snapshot;
 480
 481         callback(user, &pkth, handle->buffer);
 482         return 1;
 483 }
 484
 485 static int
 486 usb_inject_linux(pcap_t *handle, const void *buf, size_t size)
 487 {
 488         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
 489                 "USB devices");
 490         return (-1);
 491 }
 492
 493 static void
 494 usb_close_linux(pcap_t* handle)
 495 {
 496         /* handle fill be freed in pcap_close() 'common' code */
 497         close(handle->fd);
 498         if (handle->buffer)
 499                 free(handle->buffer);
 500 }
 501
 502 static int
 503 usb_stats_linux(pcap_t *handle, struct pcap_stat *stats)
 504 {
 505         int dummy, ret, consumed, cnt;
 506         char string[USB_LINE_LEN];
 507         char token[USB_LINE_LEN];
 508         char * ptr = string;
 509         snprintf(string, USB_LINE_LEN, USB_TEXT_DIR"/%ds", handle->md.ifindex);
 510
 511         int fd = open(string, O_RDONLY, 0);
 512         if (fd < 0)
 513         {
 514                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 515                         "Can't open USB stats file %s: %s",
 516                         string, strerror(errno));
 517                 return -1;
 518         }
 519
 520         /* read stats line */
 521         do {
 522                 ret = read(fd, string, USB_LINE_LEN-1);
 523         } while ((ret == -1) && (errno == EINTR));
 524         close(fd);
 525
 526         if (ret < 0)
 527         {
 528                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 529                         "Can't read stats from fd %d ", fd);
 530                 return -1;
 531         }
 532         string[ret] = 0;
 533
 534         /* extract info on dropped urbs */
 535         for (consumed=0; consumed < ret; ) {
 536                 /* from the sscanf man page:
 537                  * The C standard says: "Execution of a %n directive does
 538                  * not increment the assignment count returned at the completion
 539                  * of  execution" but the Corrigendum seems to contradict this.
 540                  * Do not make any assumptions on the effect of %n conversions
 541                  * on the return value and explicitly check for cnt assignmet*/
 542                 cnt = -1;
 543                 int ntok = sscanf(ptr, "%s%n", token, &cnt);
 544                 if ((ntok < 1) || (cnt < 0))
 545                         break;
 546                 consumed += cnt;
 547                 ptr += cnt;
 548                 if (strcmp(token, "nreaders") == 0)
 549                         ret = sscanf(ptr, "%d", &stats->ps_drop);
 550                 else
 551                         ret = sscanf(ptr, "%d", &dummy);
 552                 if (ntok != 1)
 553                         break;
 554                 consumed += cnt;
 555                 ptr += cnt;
 556         }
 557
 558         stats->ps_recv = handle->md.packets_read;
 559         stats->ps_ifdrop = 0;
 560         return 0;
 561 }
 562
 563 static int
 564 usb_setfilter_linux(pcap_t *p, struct bpf_program *fp)
 565 {
 566         return 0;
 567 }
 568
 569 static int
 570 usb_setdirection_linux(pcap_t *p, pcap_direction_t d)
 571 {
 572         p->direction = d;
 573         return 0;
 574 }
 575
 576
 577 static int
 578 usb_stats_linux_bin(pcap_t *handle, struct pcap_stat *stats)
 579 {
 580         int ret;
 581         struct mon_bin_stats st;
 582         ret = ioctl(handle->fd, MON_IOCG_STATS, &st);
 583         if (ret < 0)
 584         {
 585                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 586                         "Can't read stats from fd %d:%s ", handle->fd, strerror(errno));
 587                 return -1;
 588         }
 589
 590         stats->ps_recv = handle->md.packets_read + st.queued;
 591         stats->ps_ifdrop = st.dropped;
 592         return 0;
 593 }
 594
 595 /*
 596  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 597  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 598  */
 599 static int
 600 usb_read_linux_bin(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 601 {
 602         struct mon_bin_get info;
 603         int ret;
 604         struct pcap_pkthdr pkth;
 605         int clen = handle->snapshot - sizeof(pcap_usb_header);
 606
 607         /* the usb header is going to be part of 'packet' data*/
 608         info.hdr = (pcap_usb_header*) handle->buffer;
 609         info.data = handle->buffer + sizeof(pcap_usb_header);
 610         info.data_len = clen;
 611
 612         /* ignore interrupt system call errors */
 613         do {
 614                 ret = ioctl(handle->fd, MON_IOCX_GET, &info);
 615                 if (handle->break_loop)
 616                 {
 617                         handle->break_loop = 0;
 618                         return -2;
 619                 }
 620         } while ((ret == -1) && (errno == EINTR));
 621         if (ret < 0)
 622         {
 623                 if (errno == EAGAIN)
 624                         return 0;       /* no data there */
 625
 626                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 627                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 628                 return -1;
 629         }
 630
 631         /* we can get less that than really captured from kernel, depending on
 632          * snaplen, so adjust header accordingly */
 633         if (info.hdr->data_len < clen)
 634                 clen = info.hdr->data_len;
 635         info.hdr->data_len = clen;
 636         pkth.caplen = clen + sizeof(pcap_usb_header);
 637         pkth.len = info.hdr->urb_len + sizeof(pcap_usb_header);
 638         pkth.ts.tv_sec = info.hdr->ts_sec;
 639         pkth.ts.tv_usec = info.hdr->ts_usec;
 640
 641         handle->md.packets_read++;
 642         callback(user, &pkth, handle->buffer);
 643         return 1;
 644 }
 645
 646 /*
 647  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 648  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 649  */
 650 #define VEC_SIZE 32
 651 static int
 652 usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 653 {
 654         struct mon_bin_mfetch fetch;
 655         int32_t vec[VEC_SIZE];
 656         struct pcap_pkthdr pkth;
 657         pcap_usb_header* hdr;
 658         int nflush = 0;
 659         int packets = 0;
 660
 661         for (;;) {
 662                 int i, ret;
 663                 int limit = max_packets - packets;
 664                 if (limit <= 0)
 665                         limit = VEC_SIZE;
 666                 if (limit > VEC_SIZE)
 667                         limit = VEC_SIZE;
 668
 669                 /* try to fetch as many events as possible*/
 670                 fetch.offvec = vec;
 671                 fetch.nfetch = limit;
 672                 fetch.nflush = nflush;
 673                 /* ignore interrupt system call errors */
 674                 do {
 675                         ret = ioctl(handle->fd, MON_IOCX_MFETCH, &fetch);
 676                         if (handle->break_loop)
 677                         {
 678                                 handle->break_loop = 0;
 679                                 return -2;
 680                         }
 681                 } while ((ret == -1) && (errno == EINTR));
 682                 if (ret < 0)
 683                 {
 684                         if (errno == EAGAIN)
 685                                 return 0;       /* no data there */
 686
 687                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 688                             "Can't mfetch fd %d: %s", handle->fd, strerror(errno));
 689                         return -1;
 690                 }
 691
 692                 /* keep track of processed events, we will flush them later */
 693                 nflush = fetch.nfetch;
 694                 for (i=0; i<fetch.nfetch; ++i) {
 695                         /* discard filler */
 696                         hdr = (pcap_usb_header*) &handle->buffer[vec[i]];
 697                         if (hdr->event_type == '@')
 698                                 continue;
 699
 700                         /* get packet info from header*/
 701                         pkth.caplen = hdr->data_len + sizeof(pcap_usb_header);
 702                         pkth.len = hdr->urb_len + sizeof(pcap_usb_header);
 703                         pkth.ts.tv_sec = hdr->ts_sec;
 704                         pkth.ts.tv_usec = hdr->ts_usec;
 705
 706                         handle->md.packets_read++;
 707                         callback(user, &pkth, (u_char*) hdr);
 708                         packets++;
 709                 }
 710
 711                 /* with max_packets <= 0 we stop afer the first chunk*/
 712                 if ((max_packets <= 0) || (packets == max_packets))
 713                         break;
 714         }
 715
 716         /* flush pending events*/
 717         ioctl(handle->fd, MON_IOCH_MFLUSH, nflush);
 718         return packets;
 719 }
 720
 721 static void
 722 usb_close_linux_mmap(pcap_t* handle)
 723 {
 724         /* handle will be freed in pcap_close() 'common' code, buffer must not
 725          * be freed because it's memory mapped */
 726         close(handle->fd);
 727 }