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

   1 /*
   2  * Copyright (c) 2006 Paolo Abeni (Italy)
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote
  15  * products derived from this software without specific prior written
  16  * permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  *
  30  * USB sniffing API implementation for Linux platform
  31  * By Paolo Abeni <paolo.abeni@email.it>
  32  * Modifications: Kris Katterjohn <katterjohn@gmail.com>
  33  *
  34  */
  35 #ifndef lint
  36 static const char rcsid[] _U_ =
  37     "@(#) $Header: /tcpdump/master/libpcap/pcap-usb-linux.c,v 1.33 2008-12-23 21:38:50 guy Exp $ (LBL)";
  38 #endif
  39
  40 #ifdef HAVE_CONFIG_H
  41 #include "config.h"
  42 #endif
  43
  44 #include "pcap-int.h"
  45 #include "pcap-usb-linux.h"
  46 #include "pcap/usb.h"
  47
  48 #ifdef NEED_STRERROR_H
  49 #include "strerror.h"
  50 #endif
  51
  52 #include <ctype.h>
  53 #include <errno.h>
  54 #include <stdlib.h>
  55 #include <unistd.h>
  56 #include <fcntl.h>
  57 #include <string.h>
  58 #include <dirent.h>
  59 #include <byteswap.h>
  60 #include <netinet/in.h>
  61 #include <sys/ioctl.h>
  62 #include <sys/mman.h>
  63 #ifdef HAVE_LINUX_USBDEVICE_FS_H
  64 #include <linux/usbdevice_fs.h>
  65 #endif
  66
  67 #define USB_IFACE "usbmon"
  68 #define USB_TEXT_DIR "/sys/kernel/debug/usbmon"
  69 #define SYS_USB_BUS_DIR "/sys/bus/usb/devices"
  70 #define PROC_USB_BUS_DIR "/proc/bus/usb"
  71 #define USB_LINE_LEN 4096
  72
  73 #if __BYTE_ORDER == __LITTLE_ENDIAN
  74 #define htols(s) s
  75 #define htoll(l) l
  76 #define htol64(ll) ll
  77 #else
  78 #define htols(s) bswap_16(s)
  79 #define htoll(l) bswap_32(l)
  80 #define htol64(ll) bswap_64(ll)
  81 #endif
  82
  83 struct mon_bin_stats {
  84         u_int32_t queued;
  85         u_int32_t dropped;
  86 };
  87
  88 struct mon_bin_get {
  89         pcap_usb_header *hdr;
  90         void *data;
  91         size_t data_len;   /* Length of data (can be zero) */
  92 };
  93
  94 struct mon_bin_mfetch {
  95         int32_t *offvec;   /* Vector of events fetched */
  96         int32_t nfetch;    /* Number of events to fetch (out: fetched) */
  97         int32_t nflush;    /* Number of events to flush */
  98 };
  99
 100 #define MON_IOC_MAGIC 0x92
 101
 102 #define MON_IOCQ_URB_LEN _IO(MON_IOC_MAGIC, 1)
 103 #define MON_IOCX_URB  _IOWR(MON_IOC_MAGIC, 2, struct mon_bin_hdr)
 104 #define MON_IOCG_STATS _IOR(MON_IOC_MAGIC, 3, struct mon_bin_stats)
 105 #define MON_IOCT_RING_SIZE _IO(MON_IOC_MAGIC, 4)
 106 #define MON_IOCQ_RING_SIZE _IO(MON_IOC_MAGIC, 5)
 107 #define MON_IOCX_GET   _IOW(MON_IOC_MAGIC, 6, struct mon_bin_get)
 108 #define MON_IOCX_MFETCH _IOWR(MON_IOC_MAGIC, 7, struct mon_bin_mfetch)
 109 #define MON_IOCH_MFLUSH _IO(MON_IOC_MAGIC, 8)
 110
 111 #define MON_BIN_SETUP   0x1 /* setup hdr is present*/
 112 #define MON_BIN_SETUP_ZERO      0x2 /* setup buffer is not available */
 113 #define MON_BIN_DATA_ZERO       0x4 /* data buffer is not available */
 114 #define MON_BIN_ERROR   0x8
 115
 116 /* forward declaration */
 117 static int usb_activate(pcap_t *);
 118 static int usb_stats_linux(pcap_t *, struct pcap_stat *);
 119 static int usb_stats_linux_bin(pcap_t *, struct pcap_stat *);
 120 static int usb_read_linux(pcap_t *, int , pcap_handler , u_char *);
 121 static int usb_read_linux_bin(pcap_t *, int , pcap_handler , u_char *);
 122 static int usb_read_linux_mmap(pcap_t *, int , pcap_handler , u_char *);
 123 static int usb_inject_linux(pcap_t *, const void *, size_t);
 124 static int usb_setfilter_linux(pcap_t *, struct bpf_program *);
 125 static int usb_setdirection_linux(pcap_t *, pcap_direction_t);
 126 static void usb_cleanup_linux_mmap(pcap_t *);
 127
 128 /* facility to add an USB device to the device list*/
 129 static int
 130 usb_dev_add(pcap_if_t** alldevsp, int n, char *err_str)
 131 {
 132         char dev_name[10];
 133         char dev_descr[30];
 134         snprintf(dev_name, 10, USB_IFACE"%d", n);
 135         snprintf(dev_descr, 30, "USB bus number %d", n);
 136
 137         if (pcap_add_if(alldevsp, dev_name, 0,
 138             dev_descr, err_str) < 0)
 139                 return -1;
 140         return 0;
 141 }
 142
 143 int
 144 usb_platform_finddevs(pcap_if_t **alldevsp, char *err_str)
 145 {
 146         struct dirent* data;
 147         int ret = 0;
 148         DIR* dir;
 149         int n;
 150         char* name;
 151         size_t len;
 152
 153         /* try scanning sysfs usb bus directory */
 154         dir = opendir(SYS_USB_BUS_DIR);
 155         if (dir != NULL) {
 156                 while ((ret == 0) && ((data = readdir(dir)) != 0)) {
 157                         name = data->d_name;
 158
 159                         if (strncmp(name, "usb", 3) != 0)
 160                                 continue;
 161
 162                         if (sscanf(&name[3], "%d", &n) == 0)
 163                                 continue;
 164
 165                         ret = usb_dev_add(alldevsp, n, err_str);
 166                 }
 167
 168                 closedir(dir);
 169                 return ret;
 170         }
 171
 172         /* that didn't work; try scanning procfs usb bus directory */
 173         dir = opendir(PROC_USB_BUS_DIR);
 174         if (dir != NULL) {
 175                 while ((ret == 0) && ((data = readdir(dir)) != 0)) {
 176                         name = data->d_name;
 177                         len = strlen(name);
 178
 179                         /* if this file name does not end with a number it's not of our interest */
 180                         if ((len < 1) || !isdigit(name[--len]))
 181                                 continue;
 182                         while (isdigit(name[--len]));
 183                         if (sscanf(&name[len+1], "%d", &n) != 1)
 184                                 continue;
 185
 186                         ret = usb_dev_add(alldevsp, n, err_str);
 187                 }
 188
 189                 closedir(dir);
 190                 return ret;
 191         }
 192
 193         /* neither of them worked */
 194         return 0;
 195 }
 196
 197 static
 198 int usb_mmap(pcap_t* handle)
 199 {
 200         int len = ioctl(handle->fd, MON_IOCQ_RING_SIZE);
 201         if (len < 0)
 202                 return 0;
 203
 204         handle->md.mmapbuflen = len;
 205         handle->md.mmapbuf = mmap(0, handle->md.mmapbuflen, PROT_READ,
 206             MAP_SHARED, handle->fd, 0);
 207         return handle->md.mmapbuf != MAP_FAILED;
 208 }
 209
 210 #define CTRL_TIMEOUT    (5*1000)        /* milliseconds */
 211
 212 #define USB_DIR_IN              0x80
 213 #define USB_TYPE_STANDARD       0x00
 214 #define USB_RECIP_DEVICE        0x00
 215
 216 #define USB_REQ_GET_DESCRIPTOR  6
 217
 218 #define USB_DT_DEVICE           1
 219
 220 /* probe the descriptors of the devices attached to the bus */
 221 /* the descriptors will end up in the captured packet stream */
 222 /* and be decoded by external apps like wireshark */
 223 /* without these identifying probes packet data can't be fully decoded */
 224 static void
 225 probe_devices(int bus)
 226 {
 227         struct usbdevfs_ctrltransfer ctrl;
 228         struct dirent* data;
 229         int ret = 0;
 230         char buf[40];
 231         DIR* dir;
 232
 233         /* scan usb bus directories for device nodes */
 234         snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d", bus);
 235         dir = opendir(buf);
 236         if (!dir)
 237                 return;
 238
 239         while ((ret >= 0) && ((data = readdir(dir)) != 0)) {
 240                 int fd;
 241                 char* name = data->d_name;
 242
 243                 if (name[0] == '.')
 244                         continue;
 245
 246                 snprintf(buf, sizeof(buf), "/dev/bus/usb/%03d/%s", bus, data->d_name);
 247
 248                 fd = open(buf, O_RDWR);
 249                 if (fd == -1)
 250                         continue;
 251
 252                 /*
 253                  * Sigh.  Different kernels have different member names
 254                  * for this structure.
 255                  */
 256 #ifdef HAVE_USBDEVFS_CTRLTRANSFER_BREQUESTTYPE
 257                 ctrl.bRequestType = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
 258                 ctrl.bRequest = USB_REQ_GET_DESCRIPTOR;
 259                 ctrl.wValue = USB_DT_DEVICE << 8;
 260                 ctrl.wIndex = 0;
 261                 ctrl.wLength = sizeof(buf);
 262 #else
 263                 ctrl.requesttype = USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE;
 264                 ctrl.request = USB_REQ_GET_DESCRIPTOR;
 265                 ctrl.value = USB_DT_DEVICE << 8;
 266                 ctrl.index = 0;
 267                 ctrl.length = sizeof(buf);
 268 #endif
 269                 ctrl.data = buf;
 270                 ctrl.timeout = CTRL_TIMEOUT;
 271
 272                 ret = ioctl(fd, USBDEVFS_CONTROL, &ctrl);
 273
 274                 close(fd);
 275         }
 276         closedir(dir);
 277 }
 278
 279 pcap_t *
 280 usb_create(const char *device, char *ebuf)
 281 {
 282         pcap_t *p;
 283
 284         p = pcap_create_common(device, ebuf);
 285         if (p == NULL)
 286                 return (NULL);
 287
 288         p->activate_op = usb_activate;
 289         return (p);
 290 }
 291
 292 static int
 293 usb_activate(pcap_t* handle)
 294 {
 295         char            full_path[USB_LINE_LEN];
 296
 297         /* Initialize some components of the pcap structure. */
 298         handle->bufsize = handle->snapshot;
 299         handle->offset = 0;
 300         handle->linktype = DLT_USB_LINUX;
 301
 302         handle->inject_op = usb_inject_linux;
 303         handle->setfilter_op = usb_setfilter_linux;
 304         handle->setdirection_op = usb_setdirection_linux;
 305         handle->set_datalink_op = NULL; /* can't change data link type */
 306         handle->getnonblock_op = pcap_getnonblock_fd;
 307         handle->setnonblock_op = pcap_setnonblock_fd;
 308
 309         /*get usb bus index from device name */
 310         if (sscanf(handle->opt.source, USB_IFACE"%d", &handle->md.ifindex) != 1)
 311         {
 312                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 313                         "Can't get USB bus index from %s", handle->opt.source);
 314                 return PCAP_ERROR;
 315         }
 316
 317         /*now select the read method: try to open binary interface */
 318         snprintf(full_path, USB_LINE_LEN, LINUX_USB_MON_DEV"%d", handle->md.ifindex);
 319         handle->fd = open(full_path, O_RDONLY, 0);
 320         if (handle->fd >= 0)
 321         {
 322                 if (handle->opt.rfmon) {
 323                         /*
 324                          * Monitor mode doesn't apply to USB devices.
 325                          */
 326                         close(handle->fd);
 327                         return PCAP_ERROR_RFMON_NOTSUP;
 328                 }
 329
 330                 /* binary api is available, try to use fast mmap access */
 331                 if (usb_mmap(handle)) {
 332                         handle->linktype = DLT_USB_LINUX_MMAPPED;
 333                         handle->stats_op = usb_stats_linux_bin;
 334                         handle->read_op = usb_read_linux_mmap;
 335                         handle->cleanup_op = usb_cleanup_linux_mmap;
 336                         probe_devices(handle->md.ifindex);
 337
 338                         /*
 339                          * "handle->fd" is a real file, so "select()" and
 340                          * "poll()" work on it.
 341                          */
 342                         handle->selectable_fd = handle->fd;
 343                         return 0;
 344                 }
 345
 346                 /* can't mmap, use plain binary interface access */
 347                 handle->stats_op = usb_stats_linux_bin;
 348                 handle->read_op = usb_read_linux_bin;
 349                 probe_devices(handle->md.ifindex);
 350         }
 351         else {
 352                 /*Binary interface not available, try open text interface */
 353                 snprintf(full_path, USB_LINE_LEN, USB_TEXT_DIR"/%dt", handle->md.ifindex);
 354                 handle->fd = open(full_path, O_RDONLY, 0);
 355                 if (handle->fd < 0)
 356                 {
 357                         /* no more fallback, give it up*/
 358                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 359                                 "Can't open USB bus file %s: %s", full_path, strerror(errno));
 360                         return PCAP_ERROR;
 361                 }
 362
 363                 if (handle->opt.rfmon) {
 364                         /*
 365                          * Monitor mode doesn't apply to USB devices.
 366                          */
 367                         close(handle->fd);
 368                         return PCAP_ERROR_RFMON_NOTSUP;
 369                 }
 370
 371                 handle->stats_op = usb_stats_linux;
 372                 handle->read_op = usb_read_linux;
 373         }
 374
 375         /*
 376          * "handle->fd" is a real file, so "select()" and "poll()"
 377          * work on it.
 378          */
 379         handle->selectable_fd = handle->fd;
 380
 381         /* for plain binary access and text access we need to allocate the read
 382          * buffer */
 383         handle->buffer = malloc(handle->bufsize);
 384         if (!handle->buffer) {
 385                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 386                          "malloc: %s", pcap_strerror(errno));
 387                 close(handle->fd);
 388                 return PCAP_ERROR;
 389         }
 390         return 0;
 391 }
 392
 393 static inline int
 394 ascii_to_int(char c)
 395 {
 396         return c < 'A' ? c- '0': ((c<'a') ? c - 'A' + 10: c-'a'+10);
 397 }
 398
 399 /*
 400  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 401  * <linux-kernel-source>/drivers/usb/mon/mon_text.c for urb string
 402  * format description
 403  */
 404 static int
 405 usb_read_linux(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 406 {
 407         /* see:
 408         * /usr/src/linux/Documentation/usb/usbmon.txt
 409         * for message format
 410         */
 411         unsigned timestamp;
 412         int tag, cnt, ep_num, dev_addr, dummy, ret, urb_len, data_len;
 413         char etype, pipeid1, pipeid2, status[16], urb_tag, line[USB_LINE_LEN];
 414         char *string = line;
 415         u_char * rawdata = handle->buffer;
 416         struct pcap_pkthdr pkth;
 417         pcap_usb_header* uhdr = (pcap_usb_header*)handle->buffer;
 418         u_char urb_transfer=0;
 419         int incoming=0;
 420
 421         /* ignore interrupt system call errors */
 422         do {
 423                 ret = read(handle->fd, line, USB_LINE_LEN - 1);
 424                 if (handle->break_loop)
 425                 {
 426                         handle->break_loop = 0;
 427                         return -2;
 428                 }
 429         } while ((ret == -1) && (errno == EINTR));
 430         if (ret < 0)
 431         {
 432                 if (errno == EAGAIN)
 433                         return 0;       /* no data there */
 434
 435                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 436                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 437                 return -1;
 438         }
 439
 440         /* read urb header; %n argument may increment return value, but it's
 441         * not mandatory, so does not count on it*/
 442         string[ret] = 0;
 443         ret = sscanf(string, "%x %d %c %c%c:%d:%d %s%n", &tag, &timestamp, &etype,
 444                 &pipeid1, &pipeid2, &dev_addr, &ep_num, status,
 445                 &cnt);
 446         if (ret < 8)
 447         {
 448                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 449                     "Can't parse USB bus message '%s', too few tokens (expected 8 got %d)",
 450                     string, ret);
 451                 return -1;
 452         }
 453         uhdr->id = tag;
 454         uhdr->device_address = dev_addr;
 455         uhdr->bus_id = handle->md.ifindex;
 456         uhdr->status = 0;
 457         string += cnt;
 458
 459         /* don't use usbmon provided timestamp, since it have low precision*/
 460         if (gettimeofday(&pkth.ts, NULL) < 0)
 461         {
 462                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 463                         "Can't get timestamp for message '%s' %d:%s",
 464                         string, errno, strerror(errno));
 465                 return -1;
 466         }
 467         uhdr->ts_sec = pkth.ts.tv_sec;
 468         uhdr->ts_usec = pkth.ts.tv_usec;
 469
 470         /* parse endpoint information */
 471         if (pipeid1 == 'C')
 472                 urb_transfer = URB_CONTROL;
 473         else if (pipeid1 == 'Z')
 474                 urb_transfer = URB_ISOCHRONOUS;
 475         else if (pipeid1 == 'I')
 476                 urb_transfer = URB_INTERRUPT;
 477         else if (pipeid1 == 'B')
 478                 urb_transfer = URB_BULK;
 479         if (pipeid2 == 'i') {
 480                 ep_num |= URB_TRANSFER_IN;
 481                 incoming = 1;
 482         }
 483         if (etype == 'C')
 484                 incoming = !incoming;
 485
 486         /* direction check*/
 487         if (incoming)
 488         {
 489                 if (handle->direction == PCAP_D_OUT)
 490                         return 0;
 491         }
 492         else
 493                 if (handle->direction == PCAP_D_IN)
 494                         return 0;
 495         uhdr->event_type = etype;
 496         uhdr->transfer_type = urb_transfer;
 497         uhdr->endpoint_number = ep_num;
 498         pkth.caplen = sizeof(pcap_usb_header);
 499         rawdata += sizeof(pcap_usb_header);
 500
 501         /* check if this is a setup packet */
 502         ret = sscanf(status, "%d", &dummy);
 503         if (ret != 1)
 504         {
 505                 /* this a setup packet, setup data can be filled with underscore if
 506                 * usbmon has not been able to read them, so we must parse this fields as
 507                 * strings */
 508                 pcap_usb_setup* shdr;
 509                 char str1[3], str2[3], str3[5], str4[5], str5[5];
 510                 ret = sscanf(string, "%s %s %s %s %s%n", str1, str2, str3, str4,
 511                 str5, &cnt);
 512                 if (ret < 5)
 513                 {
 514                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 515                                 "Can't parse USB bus message '%s', too few tokens (expected 5 got %d)",
 516                                 string, ret);
 517                         return -1;
 518                 }
 519                 string += cnt;
 520
 521                 /* try to convert to corresponding integer */
 522                 shdr = &uhdr->setup;
 523                 shdr->bmRequestType = strtoul(str1, 0, 16);
 524                 shdr->bRequest = strtoul(str2, 0, 16);
 525                 shdr->wValue = htols(strtoul(str3, 0, 16));
 526                 shdr->wIndex = htols(strtoul(str4, 0, 16));
 527                 shdr->wLength = htols(strtoul(str5, 0, 16));
 528
 529                 uhdr->setup_flag = 0;
 530         }
 531         else
 532                 uhdr->setup_flag = 1;
 533
 534         /* read urb data */
 535         ret = sscanf(string, " %d%n", &urb_len, &cnt);
 536         if (ret < 1)
 537         {
 538                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 539                   "Can't parse urb length from '%s'", string);
 540                 return -1;
 541         }
 542         string += cnt;
 543
 544         /* urb tag is not present if urb length is 0, so we can stop here
 545          * text parsing */
 546         pkth.len = urb_len+pkth.caplen;
 547         uhdr->urb_len = urb_len;
 548         uhdr->data_flag = 1;
 549         data_len = 0;
 550         if (uhdr->urb_len == 0)
 551                 goto got;
 552
 553         /* check for data presence; data is present if and only if urb tag is '=' */
 554         if (sscanf(string, " %c", &urb_tag) != 1)
 555         {
 556                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 557                         "Can't parse urb tag from '%s'", string);
 558                 return -1;
 559         }
 560
 561         if (urb_tag != '=')
 562                 goto got;
 563
 564         /* skip urb tag and following space */
 565         string += 3;
 566
 567         /* if we reach this point we got some urb data*/
 568         uhdr->data_flag = 0;
 569
 570         /* read all urb data; if urb length is greater then the usbmon internal
 571          * buffer length used by the kernel to spool the URB, we get only
 572          * a partial information.
 573          * At least until linux 2.6.17 there is no way to set usbmon intenal buffer
 574          * length and default value is 130. */
 575         while ((string[0] != 0) && (string[1] != 0) && (pkth.caplen < handle->snapshot))
 576         {
 577                 rawdata[0] = ascii_to_int(string[0]) * 16 + ascii_to_int(string[1]);
 578                 rawdata++;
 579                 string+=2;
 580                 if (string[0] == ' ')
 581                         string++;
 582                 pkth.caplen++;
 583                 data_len++;
 584         }
 585
 586 got:
 587         uhdr->data_len = data_len;
 588         handle->md.packets_read++;
 589         if (pkth.caplen > handle->snapshot)
 590                 pkth.caplen = handle->snapshot;
 591
 592         callback(user, &pkth, handle->buffer);
 593         return 1;
 594 }
 595
 596 static int
 597 usb_inject_linux(pcap_t *handle, const void *buf, size_t size)
 598 {
 599         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE, "inject not supported on "
 600                 "USB devices");
 601         return (-1);
 602 }
 603
 604 static int
 605 usb_stats_linux(pcap_t *handle, struct pcap_stat *stats)
 606 {
 607         int dummy, ret, consumed, cnt;
 608         char string[USB_LINE_LEN];
 609         char token[USB_LINE_LEN];
 610         char * ptr = string;
 611         int fd;
 612
 613         snprintf(string, USB_LINE_LEN, USB_TEXT_DIR"/%ds", handle->md.ifindex);
 614         fd = open(string, O_RDONLY, 0);
 615         if (fd < 0)
 616         {
 617                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 618                         "Can't open USB stats file %s: %s",
 619                         string, strerror(errno));
 620                 return -1;
 621         }
 622
 623         /* read stats line */
 624         do {
 625                 ret = read(fd, string, USB_LINE_LEN-1);
 626         } while ((ret == -1) && (errno == EINTR));
 627         close(fd);
 628
 629         if (ret < 0)
 630         {
 631                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 632                         "Can't read stats from fd %d ", fd);
 633                 return -1;
 634         }
 635         string[ret] = 0;
 636
 637         /* extract info on dropped urbs */
 638         for (consumed=0; consumed < ret; ) {
 639                 /* from the sscanf man page:
 640                  * The C standard says: "Execution of a %n directive does
 641                  * not increment the assignment count returned at the completion
 642                  * of  execution" but the Corrigendum seems to contradict this.
 643                  * Do not make any assumptions on the effect of %n conversions
 644                  * on the return value and explicitly check for cnt assignmet*/
 645                 int ntok;
 646
 647                 cnt = -1;
 648                 ntok = sscanf(ptr, "%s%n", token, &cnt);
 649                 if ((ntok < 1) || (cnt < 0))
 650                         break;
 651                 consumed += cnt;
 652                 ptr += cnt;
 653                 if (strcmp(token, "nreaders") == 0)
 654                         ret = sscanf(ptr, "%d", &stats->ps_drop);
 655                 else
 656                         ret = sscanf(ptr, "%d", &dummy);
 657                 if (ntok != 1)
 658                         break;
 659                 consumed += cnt;
 660                 ptr += cnt;
 661         }
 662
 663         stats->ps_recv = handle->md.packets_read;
 664         stats->ps_ifdrop = 0;
 665         return 0;
 666 }
 667
 668 static int
 669 usb_setfilter_linux(pcap_t *p, struct bpf_program *fp)
 670 {
 671         return 0;
 672 }
 673
 674 static int
 675 usb_setdirection_linux(pcap_t *p, pcap_direction_t d)
 676 {
 677         p->direction = d;
 678         return 0;
 679 }
 680
 681
 682 static int
 683 usb_stats_linux_bin(pcap_t *handle, struct pcap_stat *stats)
 684 {
 685         int ret;
 686         struct mon_bin_stats st;
 687         ret = ioctl(handle->fd, MON_IOCG_STATS, &st);
 688         if (ret < 0)
 689         {
 690                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 691                         "Can't read stats from fd %d:%s ", handle->fd, strerror(errno));
 692                 return -1;
 693         }
 694
 695         stats->ps_recv = handle->md.packets_read + st.queued;
 696         stats->ps_drop = st.dropped;
 697         stats->ps_ifdrop = 0;
 698         return 0;
 699 }
 700
 701 /*
 702  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 703  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 704  */
 705 static int
 706 usb_read_linux_bin(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 707 {
 708         struct mon_bin_get info;
 709         int ret;
 710         struct pcap_pkthdr pkth;
 711         int clen = handle->snapshot - sizeof(pcap_usb_header);
 712
 713         /* the usb header is going to be part of 'packet' data*/
 714         info.hdr = (pcap_usb_header*) handle->buffer;
 715         info.data = handle->buffer + sizeof(pcap_usb_header);
 716         info.data_len = clen;
 717
 718         /* ignore interrupt system call errors */
 719         do {
 720                 ret = ioctl(handle->fd, MON_IOCX_GET, &info);
 721                 if (handle->break_loop)
 722                 {
 723                         handle->break_loop = 0;
 724                         return -2;
 725                 }
 726         } while ((ret == -1) && (errno == EINTR));
 727         if (ret < 0)
 728         {
 729                 if (errno == EAGAIN)
 730                         return 0;       /* no data there */
 731
 732                 snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 733                     "Can't read from fd %d: %s", handle->fd, strerror(errno));
 734                 return -1;
 735         }
 736
 737         /* we can get less that than really captured from kernel, depending on
 738          * snaplen, so adjust header accordingly */
 739         if (info.hdr->data_len < clen)
 740                 clen = info.hdr->data_len;
 741         info.hdr->data_len = clen;
 742         pkth.caplen = clen + sizeof(pcap_usb_header);
 743         pkth.len = info.hdr->data_len + sizeof(pcap_usb_header);
 744         pkth.ts.tv_sec = info.hdr->ts_sec;
 745         pkth.ts.tv_usec = info.hdr->ts_usec;
 746
 747         handle->md.packets_read++;
 748         callback(user, &pkth, handle->buffer);
 749         return 1;
 750 }
 751
 752 /*
 753  * see <linux-kernel-source>/Documentation/usb/usbmon.txt and
 754  * <linux-kernel-source>/drivers/usb/mon/mon_bin.c binary ABI
 755  */
 756 #define VEC_SIZE 32
 757 static int
 758 usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_char *user)
 759 {
 760         struct mon_bin_mfetch fetch;
 761         int32_t vec[VEC_SIZE];
 762         struct pcap_pkthdr pkth;
 763         pcap_usb_header* hdr;
 764         int nflush = 0;
 765         int packets = 0;
 766         int clen, max_clen;
 767
 768         max_clen = handle->snapshot - sizeof(pcap_usb_header);
 769
 770         for (;;) {
 771                 int i, ret;
 772                 int limit = max_packets - packets;
 773                 if (limit <= 0)
 774                         limit = VEC_SIZE;
 775                 if (limit > VEC_SIZE)
 776                         limit = VEC_SIZE;
 777
 778                 /* try to fetch as many events as possible*/
 779                 fetch.offvec = vec;
 780                 fetch.nfetch = limit;
 781                 fetch.nflush = nflush;
 782                 /* ignore interrupt system call errors */
 783                 do {
 784                         ret = ioctl(handle->fd, MON_IOCX_MFETCH, &fetch);
 785                         if (handle->break_loop)
 786                         {
 787                                 handle->break_loop = 0;
 788                                 return -2;
 789                         }
 790                 } while ((ret == -1) && (errno == EINTR));
 791                 if (ret < 0)
 792                 {
 793                         if (errno == EAGAIN)
 794                                 return 0;       /* no data there */
 795
 796                         snprintf(handle->errbuf, PCAP_ERRBUF_SIZE,
 797                             "Can't mfetch fd %d: %s", handle->fd, strerror(errno));
 798                         return -1;
 799                 }
 800
 801                 /* keep track of processed events, we will flush them later */
 802                 nflush = fetch.nfetch;
 803                 for (i=0; i<fetch.nfetch; ++i) {
 804                         /* discard filler */
 805                         hdr = (pcap_usb_header*) &handle->md.mmapbuf[vec[i]];
 806                         if (hdr->event_type == '@')
 807                                 continue;
 808
 809                         /* we can get less that than really captured from kernel, depending on
 810                         * snaplen, so adjust header accordingly */
 811                         clen = max_clen;
 812                         if (hdr->data_len < clen)
 813                                 clen = hdr->data_len;
 814
 815                         /* get packet info from header*/
 816                         pkth.caplen = clen + sizeof(pcap_usb_header_mmapped);
 817                         pkth.len = hdr->data_len + sizeof(pcap_usb_header_mmapped);
 818                         pkth.ts.tv_sec = hdr->ts_sec;
 819                         pkth.ts.tv_usec = hdr->ts_usec;
 820
 821                         handle->md.packets_read++;
 822                         callback(user, &pkth, (u_char*) hdr);
 823                         packets++;
 824                 }
 825
 826                 /* with max_packets <= 0 we stop afer the first chunk*/
 827                 if ((max_packets <= 0) || (packets == max_packets))
 828                         break;
 829         }
 830
 831         /* flush pending events*/
 832         ioctl(handle->fd, MON_IOCH_MFLUSH, nflush);
 833         return packets;
 834 }
 835
 836 static void
 837 usb_cleanup_linux_mmap(pcap_t* handle)
 838 {
 839         /* if we have a memory-mapped buffer, unmap it */
 840         if (handle->md.mmapbuf != NULL) {
 841                 munmap(handle->md.mmapbuf, handle->md.mmapbuflen);
 842                 handle->md.mmapbuf = NULL;
 843         }
 844         pcap_cleanup_live_common(handle);
 845 }