usb_parse.c

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    1 /* $FreeBSD: releng/8.3/sys/dev/usb/usb_parse.c 221125 2011-04-27 18:00:46Z jhb $ */
    2 /*-
    3  * Copyright (c) 2008 Hans Petter Selasky. 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  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/stdint.h>
   28 #include <sys/stddef.h>
   29 #include <sys/param.h>
   30 #include <sys/queue.h>
   31 #include <sys/types.h>
   32 #include <sys/systm.h>
   33 #include <sys/kernel.h>
   34 #include <sys/bus.h>
   35 #include <sys/module.h>
   36 #include <sys/lock.h>
   37 #include <sys/mutex.h>
   38 #include <sys/condvar.h>
   39 #include <sys/sysctl.h>
   40 #include <sys/sx.h>
   41 #include <sys/unistd.h>
   42 #include <sys/callout.h>
   43 #include <sys/malloc.h>
   44 #include <sys/priv.h>
   45 
   46 #include <dev/usb/usb.h>
   47 #include <dev/usb/usbdi.h>
   48 #include <dev/usb/usbdi_util.h>
   49 
   50 
   51 /*------------------------------------------------------------------------*
   52  *      usb_desc_foreach
   53  *
   54  * This function is the safe way to iterate across the USB config
   55  * descriptor. It contains several checks against invalid
   56  * descriptors. If the "desc" argument passed to this function is
   57  * "NULL" the first descriptor, if any, will be returned.
   58  *
   59  * Return values:
   60  *   NULL: End of descriptors
   61  *   Else: Next descriptor after "desc"
   62  *------------------------------------------------------------------------*/
   63 struct usb_descriptor *
   64 usb_desc_foreach(struct usb_config_descriptor *cd, 
   65     struct usb_descriptor *_desc)
   66 {
   67         uint8_t *desc_next;
   68         uint8_t *start;
   69         uint8_t *end;
   70         uint8_t *desc;
   71 
   72         /* be NULL safe */
   73         if (cd == NULL)
   74                 return (NULL);
   75 
   76         /* We assume that the "wTotalLength" has been checked. */
   77         start = (uint8_t *)cd;
   78         end = start + UGETW(cd->wTotalLength);
   79         desc = (uint8_t *)_desc;
   80 
   81         /* Get start of next USB descriptor. */
   82         if (desc == NULL)
   83                 desc = start;
   84         else
   85                 desc = desc + desc[0];
   86 
   87         /* Check that the next USB descriptor is within the range. */
   88         if ((desc < start) || (desc >= end))
   89                 return (NULL);          /* out of range, or EOD */
   90 
   91         /* Check that the second next USB descriptor is within range. */
   92         desc_next = desc + desc[0];
   93         if ((desc_next < start) || (desc_next > end))
   94                 return (NULL);          /* out of range */
   95 
   96         /* Check minimum descriptor length. */
   97         if (desc[0] < 3)
   98                 return (NULL);          /* too short descriptor */
   99 
  100         /* Return start of next descriptor. */
  101         return ((struct usb_descriptor *)desc);
  102 }
  103 
  104 /*------------------------------------------------------------------------*
  105  *      usb_idesc_foreach
  106  *
  107  * This function will iterate the interface descriptors in the config
  108  * descriptor. The parse state structure should be zeroed before
  109  * calling this function the first time.
  110  *
  111  * Return values:
  112  *   NULL: End of descriptors
  113  *   Else: A valid interface descriptor
  114  *------------------------------------------------------------------------*/
  115 struct usb_interface_descriptor *
  116 usb_idesc_foreach(struct usb_config_descriptor *cd,
  117     struct usb_idesc_parse_state *ps)
  118 {
  119         struct usb_interface_descriptor *id;
  120         uint8_t new_iface;
  121 
  122         /* retrieve current descriptor */
  123         id = (struct usb_interface_descriptor *)ps->desc;
  124         /* default is to start a new interface */
  125         new_iface = 1;
  126 
  127         while (1) {
  128                 id = (struct usb_interface_descriptor *)
  129                     usb_desc_foreach(cd, (struct usb_descriptor *)id);
  130                 if (id == NULL)
  131                         break;
  132                 if ((id->bDescriptorType == UDESC_INTERFACE) &&
  133                     (id->bLength >= sizeof(*id))) {
  134                         if (ps->iface_no_last == id->bInterfaceNumber)
  135                                 new_iface = 0;
  136                         ps->iface_no_last = id->bInterfaceNumber;
  137                         break;
  138                 }
  139         }
  140 
  141         if (ps->desc == NULL) {
  142                 /* first time */
  143         } else if (new_iface) {
  144                 /* new interface */
  145                 ps->iface_index ++;
  146                 ps->iface_index_alt = 0;
  147         } else {
  148                 /* new alternate interface */
  149                 ps->iface_index_alt ++;
  150         }
  151 
  152         /* store and return current descriptor */
  153         ps->desc = (struct usb_descriptor *)id;
  154         return (id);
  155 }
  156 
  157 /*------------------------------------------------------------------------*
  158  *      usb_edesc_foreach
  159  *
  160  * This function will iterate all the endpoint descriptors within an
  161  * interface descriptor. Starting value for the "ped" argument should
  162  * be a valid interface descriptor.
  163  *
  164  * Return values:
  165  *   NULL: End of descriptors
  166  *   Else: A valid endpoint descriptor
  167  *------------------------------------------------------------------------*/
  168 struct usb_endpoint_descriptor *
  169 usb_edesc_foreach(struct usb_config_descriptor *cd,
  170     struct usb_endpoint_descriptor *ped)
  171 {
  172         struct usb_descriptor *desc;
  173 
  174         desc = ((struct usb_descriptor *)ped);
  175 
  176         while ((desc = usb_desc_foreach(cd, desc))) {
  177                 if (desc->bDescriptorType == UDESC_INTERFACE) {
  178                         break;
  179                 }
  180                 if (desc->bDescriptorType == UDESC_ENDPOINT) {
  181                         if (desc->bLength < sizeof(*ped)) {
  182                                 /* endpoint descriptor is invalid */
  183                                 break;
  184                         }
  185                         return ((struct usb_endpoint_descriptor *)desc);
  186                 }
  187         }
  188         return (NULL);
  189 }
  190 
  191 /*------------------------------------------------------------------------*
  192  *      usb_ed_comp_foreach
  193  *
  194  * This function will iterate all the endpoint companion descriptors
  195  * within an endpoint descriptor in an interface descriptor. Starting
  196  * value for the "ped" argument should be a valid endpoint companion
  197  * descriptor.
  198  *
  199  * Return values:
  200  *   NULL: End of descriptors
  201  *   Else: A valid endpoint companion descriptor
  202  *------------------------------------------------------------------------*/
  203 struct usb_endpoint_ss_comp_descriptor *
  204 usb_ed_comp_foreach(struct usb_config_descriptor *cd,
  205     struct usb_endpoint_ss_comp_descriptor *ped)
  206 {
  207         struct usb_descriptor *desc;
  208 
  209         desc = ((struct usb_descriptor *)ped);
  210 
  211         while ((desc = usb_desc_foreach(cd, desc))) {
  212                 if (desc->bDescriptorType == UDESC_INTERFACE)
  213                         break;
  214                 if (desc->bDescriptorType == UDESC_ENDPOINT)
  215                         break;
  216                 if (desc->bDescriptorType == UDESC_ENDPOINT_SS_COMP) {
  217                         if (desc->bLength < sizeof(*ped)) {
  218                                 /* endpoint companion descriptor is invalid */
  219                                 break;
  220                         }
  221                         return ((struct usb_endpoint_ss_comp_descriptor *)desc);
  222                 }
  223         }
  224         return (NULL);
  225 }
  226 
  227 /*------------------------------------------------------------------------*
  228  *      usbd_get_no_descriptors
  229  *
  230  * This function will count the total number of descriptors in the
  231  * configuration descriptor of type "type".
  232  *------------------------------------------------------------------------*/
  233 uint8_t
  234 usbd_get_no_descriptors(struct usb_config_descriptor *cd, uint8_t type)
  235 {
  236         struct usb_descriptor *desc = NULL;
  237         uint8_t count = 0;
  238 
  239         while ((desc = usb_desc_foreach(cd, desc))) {
  240                 if (desc->bDescriptorType == type) {
  241                         count++;
  242                         if (count == 0xFF)
  243                                 break;                  /* crazy */
  244                 }
  245         }
  246         return (count);
  247 }
  248 
  249 /*------------------------------------------------------------------------*
  250  *      usbd_get_no_alts
  251  *
  252  * Return value:
  253  *   Number of alternate settings for the given interface descriptor
  254  *   pointer. If the USB descriptor is corrupt, the returned value can
  255  *   be greater than the actual number of alternate settings.
  256  *------------------------------------------------------------------------*/
  257 uint8_t
  258 usbd_get_no_alts(struct usb_config_descriptor *cd,
  259     struct usb_interface_descriptor *id)
  260 {
  261         struct usb_descriptor *desc;
  262         uint8_t n;
  263         uint8_t ifaceno;
  264 
  265         /* Reset interface count */
  266 
  267         n = 0;
  268 
  269         /* Get the interface number */
  270 
  271         ifaceno = id->bInterfaceNumber;
  272 
  273         /* Iterate all the USB descriptors */
  274 
  275         desc = NULL;
  276         while ((desc = usb_desc_foreach(cd, desc))) {
  277                 if ((desc->bDescriptorType == UDESC_INTERFACE) &&
  278                     (desc->bLength >= sizeof(*id))) {
  279                         id = (struct usb_interface_descriptor *)desc;
  280                         if (id->bInterfaceNumber == ifaceno) {
  281                                 n++;
  282                                 if (n == 0xFF)
  283                                         break;          /* crazy */
  284                         }
  285                 }
  286         }
  287         return (n);
  288 }
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FreeBSD/Linux Kernel Cross Reference sys/dev/usb/usb_parse.c

FreeBSD/Linux Kernel Cross Reference
sys/dev/usb/usb_parse.c
