drivers/usb/gadget/f_rndis.c

   1 /*
   2  * f_rndis.c -- RNDIS link function driver
   3  *
   4  * Copyright (C) 2003-2005,2008 David Brownell
   5  * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
   6  * Copyright (C) 2008 Nokia Corporation
   7  * Copyright (C) 2009 Samsung Electronics
   8  *                    Author: Michal Nazarewicz (mina86@mina86.com)
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  */
  15
  16 /* #define VERBOSE_DEBUG */
  17
  18 #include <linux/slab.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/device.h>
  22 #include <linux/etherdevice.h>
  23
  24 #include <linux/atomic.h>
  25
  26 #include "u_ether.h"
  27 #include "u_ether_configfs.h"
  28 #include "u_rndis.h"
  29 #include "rndis.h"
  30 #include "configfs.h"
  31
  32 /*
  33  * This function is an RNDIS Ethernet port -- a Microsoft protocol that's
  34  * been promoted instead of the standard CDC Ethernet.  The published RNDIS
  35  * spec is ambiguous, incomplete, and needlessly complex.  Variants such as
  36  * ActiveSync have even worse status in terms of specification.
  37  *
  38  * In short:  it's a protocol controlled by (and for) Microsoft, not for an
  39  * Open ecosystem or markets.  Linux supports it *only* because Microsoft
  40  * doesn't support the CDC Ethernet standard.
  41  *
  42  * The RNDIS data transfer model is complex, with multiple Ethernet packets
  43  * per USB message, and out of band data.  The control model is built around
  44  * what's essentially an "RNDIS RPC" protocol.  It's all wrapped in a CDC ACM
  45  * (modem, not Ethernet) veneer, with those ACM descriptors being entirely
  46  * useless (they're ignored).  RNDIS expects to be the only function in its
  47  * configuration, so it's no real help if you need composite devices; and
  48  * it expects to be the first configuration too.
  49  *
  50  * There is a single technical advantage of RNDIS over CDC Ethernet, if you
  51  * discount the fluff that its RPC can be made to deliver: it doesn't need
  52  * a NOP altsetting for the data interface.  That lets it work on some of the
  53  * "so smart it's stupid" hardware which takes over configuration changes
  54  * from the software, and adds restrictions like "no altsettings".
  55  *
  56  * Unfortunately MSFT's RNDIS drivers are buggy.  They hang or oops, and
  57  * have all sorts of contrary-to-specification oddities that can prevent
  58  * them from working sanely.  Since bugfixes (or accurate specs, letting
  59  * Linux work around those bugs) are unlikely to ever come from MSFT, you
  60  * may want to avoid using RNDIS on purely operational grounds.
  61  *
  62  * Omissions from the RNDIS 1.0 specification include:
  63  *
  64  *   - Power management ... references data that's scattered around lots
  65  *     of other documentation, which is incorrect/incomplete there too.
  66  *
  67  *   - There are various undocumented protocol requirements, like the need
  68  *     to send garbage in some control-OUT messages.
  69  *
  70  *   - MS-Windows drivers sometimes emit undocumented requests.
  71  */
  72
  73 struct f_rndis {
  74         struct gether                   port;
  75         u8                              ctrl_id, data_id;
  76         u8                              ethaddr[ETH_ALEN];
  77         u32                             vendorID;
  78         const char                      *manufacturer;
  79         int                             config;
  80
  81         struct usb_ep                   *notify;
  82         struct usb_request              *notify_req;
  83         atomic_t                        notify_count;
  84 };
  85
  86 static inline struct f_rndis *func_to_rndis(struct usb_function *f)
  87 {
  88         return container_of(f, struct f_rndis, port.func);
  89 }
  90
  91 /* peak (theoretical) bulk transfer rate in bits-per-second */
  92 static unsigned int bitrate(struct usb_gadget *g)
  93 {
  94         if (gadget_is_superspeed(g) && g->speed == USB_SPEED_SUPER)
  95                 return 13 * 1024 * 8 * 1000 * 8;
  96         else if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
  97                 return 13 * 512 * 8 * 1000 * 8;
  98         else
  99                 return 19 * 64 * 1 * 1000 * 8;
 100 }
 101
 102 /*-------------------------------------------------------------------------*/
 103
 104 /*
 105  */
 106
 107 #define RNDIS_STATUS_INTERVAL_MS        32
 108 #define STATUS_BYTECOUNT                8       /* 8 bytes data */
 109
 110
 111 /* interface descriptor: */
 112
 113 static struct usb_interface_descriptor rndis_control_intf = {
 114         .bLength =              sizeof rndis_control_intf,
 115         .bDescriptorType =      USB_DT_INTERFACE,
 116
 117         /* .bInterfaceNumber = DYNAMIC */
 118         /* status endpoint is optional; this could be patched later */
 119         .bNumEndpoints =        1,
 120         .bInterfaceClass =      USB_CLASS_COMM,
 121         .bInterfaceSubClass =   USB_CDC_SUBCLASS_ACM,
 122         .bInterfaceProtocol =   USB_CDC_ACM_PROTO_VENDOR,
 123         /* .iInterface = DYNAMIC */
 124 };
 125
 126 static struct usb_cdc_header_desc header_desc = {
 127         .bLength =              sizeof header_desc,
 128         .bDescriptorType =      USB_DT_CS_INTERFACE,
 129         .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
 130
 131         .bcdCDC =               cpu_to_le16(0x0110),
 132 };
 133
 134 static struct usb_cdc_call_mgmt_descriptor call_mgmt_descriptor = {
 135         .bLength =              sizeof call_mgmt_descriptor,
 136         .bDescriptorType =      USB_DT_CS_INTERFACE,
 137         .bDescriptorSubType =   USB_CDC_CALL_MANAGEMENT_TYPE,
 138
 139         .bmCapabilities =       0x00,
 140         .bDataInterface =       0x01,
 141 };
 142
 143 static struct usb_cdc_acm_descriptor rndis_acm_descriptor = {
 144         .bLength =              sizeof rndis_acm_descriptor,
 145         .bDescriptorType =      USB_DT_CS_INTERFACE,
 146         .bDescriptorSubType =   USB_CDC_ACM_TYPE,
 147
 148         .bmCapabilities =       0x00,
 149 };
 150
 151 static struct usb_cdc_union_desc rndis_union_desc = {
 152         .bLength =              sizeof(rndis_union_desc),
 153         .bDescriptorType =      USB_DT_CS_INTERFACE,
 154         .bDescriptorSubType =   USB_CDC_UNION_TYPE,
 155         /* .bMasterInterface0 = DYNAMIC */
 156         /* .bSlaveInterface0 =  DYNAMIC */
 157 };
 158
 159 /* the data interface has two bulk endpoints */
 160
 161 static struct usb_interface_descriptor rndis_data_intf = {
 162         .bLength =              sizeof rndis_data_intf,
 163         .bDescriptorType =      USB_DT_INTERFACE,
 164
 165         /* .bInterfaceNumber = DYNAMIC */
 166         .bNumEndpoints =        2,
 167         .bInterfaceClass =      USB_CLASS_CDC_DATA,
 168         .bInterfaceSubClass =   0,
 169         .bInterfaceProtocol =   0,
 170         /* .iInterface = DYNAMIC */
 171 };
 172
 173
 174 static struct usb_interface_assoc_descriptor
 175 rndis_iad_descriptor = {
 176         .bLength =              sizeof rndis_iad_descriptor,
 177         .bDescriptorType =      USB_DT_INTERFACE_ASSOCIATION,
 178
 179         .bFirstInterface =      0, /* XXX, hardcoded */
 180         .bInterfaceCount =      2,      // control + data
 181         .bFunctionClass =       USB_CLASS_COMM,
 182         .bFunctionSubClass =    USB_CDC_SUBCLASS_ETHERNET,
 183         .bFunctionProtocol =    USB_CDC_PROTO_NONE,
 184         /* .iFunction = DYNAMIC */
 185 };
 186
 187 /* full speed support: */
 188
 189 static struct usb_endpoint_descriptor fs_notify_desc = {
 190         .bLength =              USB_DT_ENDPOINT_SIZE,
 191         .bDescriptorType =      USB_DT_ENDPOINT,
 192
 193         .bEndpointAddress =     USB_DIR_IN,
 194         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 195         .wMaxPacketSize =       cpu_to_le16(STATUS_BYTECOUNT),
 196         .bInterval =            RNDIS_STATUS_INTERVAL_MS,
 197 };
 198
 199 static struct usb_endpoint_descriptor fs_in_desc = {
 200         .bLength =              USB_DT_ENDPOINT_SIZE,
 201         .bDescriptorType =      USB_DT_ENDPOINT,
 202
 203         .bEndpointAddress =     USB_DIR_IN,
 204         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 205 };
 206
 207 static struct usb_endpoint_descriptor fs_out_desc = {
 208         .bLength =              USB_DT_ENDPOINT_SIZE,
 209         .bDescriptorType =      USB_DT_ENDPOINT,
 210
 211         .bEndpointAddress =     USB_DIR_OUT,
 212         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 213 };
 214
 215 static struct usb_descriptor_header *eth_fs_function[] = {
 216         (struct usb_descriptor_header *) &rndis_iad_descriptor,
 217
 218         /* control interface matches ACM, not Ethernet */
 219         (struct usb_descriptor_header *) &rndis_control_intf,
 220         (struct usb_descriptor_header *) &header_desc,
 221         (struct usb_descriptor_header *) &call_mgmt_descriptor,
 222         (struct usb_descriptor_header *) &rndis_acm_descriptor,
 223         (struct usb_descriptor_header *) &rndis_union_desc,
 224         (struct usb_descriptor_header *) &fs_notify_desc,
 225
 226         /* data interface has no altsetting */
 227         (struct usb_descriptor_header *) &rndis_data_intf,
 228         (struct usb_descriptor_header *) &fs_in_desc,
 229         (struct usb_descriptor_header *) &fs_out_desc,
 230         NULL,
 231 };
 232
 233 /* high speed support: */
 234
 235 static struct usb_endpoint_descriptor hs_notify_desc = {
 236         .bLength =              USB_DT_ENDPOINT_SIZE,
 237         .bDescriptorType =      USB_DT_ENDPOINT,
 238
 239         .bEndpointAddress =     USB_DIR_IN,
 240         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 241         .wMaxPacketSize =       cpu_to_le16(STATUS_BYTECOUNT),
 242         .bInterval =            USB_MS_TO_HS_INTERVAL(RNDIS_STATUS_INTERVAL_MS)
 243 };
 244
 245 static struct usb_endpoint_descriptor hs_in_desc = {
 246         .bLength =              USB_DT_ENDPOINT_SIZE,
 247         .bDescriptorType =      USB_DT_ENDPOINT,
 248
 249         .bEndpointAddress =     USB_DIR_IN,
 250         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 251         .wMaxPacketSize =       cpu_to_le16(512),
 252 };
 253
 254 static struct usb_endpoint_descriptor hs_out_desc = {
 255         .bLength =              USB_DT_ENDPOINT_SIZE,
 256         .bDescriptorType =      USB_DT_ENDPOINT,
 257
 258         .bEndpointAddress =     USB_DIR_OUT,
 259         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 260         .wMaxPacketSize =       cpu_to_le16(512),
 261 };
 262
 263 static struct usb_descriptor_header *eth_hs_function[] = {
 264         (struct usb_descriptor_header *) &rndis_iad_descriptor,
 265
 266         /* control interface matches ACM, not Ethernet */
 267         (struct usb_descriptor_header *) &rndis_control_intf,
 268         (struct usb_descriptor_header *) &header_desc,
 269         (struct usb_descriptor_header *) &call_mgmt_descriptor,
 270         (struct usb_descriptor_header *) &rndis_acm_descriptor,
 271         (struct usb_descriptor_header *) &rndis_union_desc,
 272         (struct usb_descriptor_header *) &hs_notify_desc,
 273
 274         /* data interface has no altsetting */
 275         (struct usb_descriptor_header *) &rndis_data_intf,
 276         (struct usb_descriptor_header *) &hs_in_desc,
 277         (struct usb_descriptor_header *) &hs_out_desc,
 278         NULL,
 279 };
 280
 281 /* super speed support: */
 282
 283 static struct usb_endpoint_descriptor ss_notify_desc = {
 284         .bLength =              USB_DT_ENDPOINT_SIZE,
 285         .bDescriptorType =      USB_DT_ENDPOINT,
 286
 287         .bEndpointAddress =     USB_DIR_IN,
 288         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 289         .wMaxPacketSize =       cpu_to_le16(STATUS_BYTECOUNT),
 290         .bInterval =            USB_MS_TO_HS_INTERVAL(RNDIS_STATUS_INTERVAL_MS)
 291 };
 292
 293 static struct usb_ss_ep_comp_descriptor ss_intr_comp_desc = {
 294         .bLength =              sizeof ss_intr_comp_desc,
 295         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 296
 297         /* the following 3 values can be tweaked if necessary */
 298         /* .bMaxBurst =         0, */
 299         /* .bmAttributes =      0, */
 300         .wBytesPerInterval =    cpu_to_le16(STATUS_BYTECOUNT),
 301 };
 302
 303 static struct usb_endpoint_descriptor ss_in_desc = {
 304         .bLength =              USB_DT_ENDPOINT_SIZE,
 305         .bDescriptorType =      USB_DT_ENDPOINT,
 306
 307         .bEndpointAddress =     USB_DIR_IN,
 308         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 309         .wMaxPacketSize =       cpu_to_le16(1024),
 310 };
 311
 312 static struct usb_endpoint_descriptor ss_out_desc = {
 313         .bLength =              USB_DT_ENDPOINT_SIZE,
 314         .bDescriptorType =      USB_DT_ENDPOINT,
 315
 316         .bEndpointAddress =     USB_DIR_OUT,
 317         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 318         .wMaxPacketSize =       cpu_to_le16(1024),
 319 };
 320
 321 static struct usb_ss_ep_comp_descriptor ss_bulk_comp_desc = {
 322         .bLength =              sizeof ss_bulk_comp_desc,
 323         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 324
 325         /* the following 2 values can be tweaked if necessary */
 326         /* .bMaxBurst =         0, */
 327         /* .bmAttributes =      0, */
 328 };
 329
 330 static struct usb_descriptor_header *eth_ss_function[] = {
 331         (struct usb_descriptor_header *) &rndis_iad_descriptor,
 332
 333         /* control interface matches ACM, not Ethernet */
 334         (struct usb_descriptor_header *) &rndis_control_intf,
 335         (struct usb_descriptor_header *) &header_desc,
 336         (struct usb_descriptor_header *) &call_mgmt_descriptor,
 337         (struct usb_descriptor_header *) &rndis_acm_descriptor,
 338         (struct usb_descriptor_header *) &rndis_union_desc,
 339         (struct usb_descriptor_header *) &ss_notify_desc,
 340         (struct usb_descriptor_header *) &ss_intr_comp_desc,
 341
 342         /* data interface has no altsetting */
 343         (struct usb_descriptor_header *) &rndis_data_intf,
 344         (struct usb_descriptor_header *) &ss_in_desc,
 345         (struct usb_descriptor_header *) &ss_bulk_comp_desc,
 346         (struct usb_descriptor_header *) &ss_out_desc,
 347         (struct usb_descriptor_header *) &ss_bulk_comp_desc,
 348         NULL,
 349 };
 350
 351 /* string descriptors: */
 352
 353 static struct usb_string rndis_string_defs[] = {
 354         [0].s = "RNDIS Communications Control",
 355         [1].s = "RNDIS Ethernet Data",
 356         [2].s = "RNDIS",
 357         {  } /* end of list */
 358 };
 359
 360 static struct usb_gadget_strings rndis_string_table = {
 361         .language =             0x0409, /* en-us */
 362         .strings =              rndis_string_defs,
 363 };
 364
 365 static struct usb_gadget_strings *rndis_strings[] = {
 366         &rndis_string_table,
 367         NULL,
 368 };
 369
 370 /*-------------------------------------------------------------------------*/
 371
 372 static struct sk_buff *rndis_add_header(struct gether *port,
 373                                         struct sk_buff *skb)
 374 {
 375         struct sk_buff *skb2;
 376
 377         skb2 = skb_realloc_headroom(skb, sizeof(struct rndis_packet_msg_type));
 378         if (skb2)
 379                 rndis_add_hdr(skb2);
 380
 381         dev_kfree_skb(skb);
 382         return skb2;
 383 }
 384
 385 static void rndis_response_available(void *_rndis)
 386 {
 387         struct f_rndis                  *rndis = _rndis;
 388         struct usb_request              *req = rndis->notify_req;
 389         struct usb_composite_dev        *cdev = rndis->port.func.config->cdev;
 390         __le32                          *data = req->buf;
 391         int                             status;
 392
 393         if (atomic_inc_return(&rndis->notify_count) != 1)
 394                 return;
 395
 396         /* Send RNDIS RESPONSE_AVAILABLE notification; a
 397          * USB_CDC_NOTIFY_RESPONSE_AVAILABLE "should" work too
 398          *
 399          * This is the only notification defined by RNDIS.
 400          */
 401         data[0] = cpu_to_le32(1);
 402         data[1] = cpu_to_le32(0);
 403
 404         status = usb_ep_queue(rndis->notify, req, GFP_ATOMIC);
 405         if (status) {
 406                 atomic_dec(&rndis->notify_count);
 407                 DBG(cdev, "notify/0 --> %d\n", status);
 408         }
 409 }
 410
 411 static void rndis_response_complete(struct usb_ep *ep, struct usb_request *req)
 412 {
 413         struct f_rndis                  *rndis = req->context;
 414         struct usb_composite_dev        *cdev = rndis->port.func.config->cdev;
 415         int                             status = req->status;
 416
 417         /* after TX:
 418          *  - USB_CDC_GET_ENCAPSULATED_RESPONSE (ep0/control)
 419          *  - RNDIS_RESPONSE_AVAILABLE (status/irq)
 420          */
 421         switch (status) {
 422         case -ECONNRESET:
 423         case -ESHUTDOWN:
 424                 /* connection gone */
 425                 atomic_set(&rndis->notify_count, 0);
 426                 break;
 427         default:
 428                 DBG(cdev, "RNDIS %s response error %d, %d/%d\n",
 429                         ep->name, status,
 430                         req->actual, req->length);
 431                 /* FALLTHROUGH */
 432         case 0:
 433                 if (ep != rndis->notify)
 434                         break;
 435
 436                 /* handle multiple pending RNDIS_RESPONSE_AVAILABLE
 437                  * notifications by resending until we're done
 438                  */
 439                 if (atomic_dec_and_test(&rndis->notify_count))
 440                         break;
 441                 status = usb_ep_queue(rndis->notify, req, GFP_ATOMIC);
 442                 if (status) {
 443                         atomic_dec(&rndis->notify_count);
 444                         DBG(cdev, "notify/1 --> %d\n", status);
 445                 }
 446                 break;
 447         }
 448 }
 449
 450 static void rndis_command_complete(struct usb_ep *ep, struct usb_request *req)
 451 {
 452         struct f_rndis                  *rndis = req->context;
 453         int                             status;
 454
 455         /* received RNDIS command from USB_CDC_SEND_ENCAPSULATED_COMMAND */
 456 //      spin_lock(&dev->lock);
 457         status = rndis_msg_parser(rndis->config, (u8 *) req->buf);
 458         if (status < 0)
 459                 pr_err("RNDIS command error %d, %d/%d\n",
 460                         status, req->actual, req->length);
 461 //      spin_unlock(&dev->lock);
 462 }
 463
 464 static int
 465 rndis_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 466 {
 467         struct f_rndis          *rndis = func_to_rndis(f);
 468         struct usb_composite_dev *cdev = f->config->cdev;
 469         struct usb_request      *req = cdev->req;
 470         int                     value = -EOPNOTSUPP;
 471         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 472         u16                     w_value = le16_to_cpu(ctrl->wValue);
 473         u16                     w_length = le16_to_cpu(ctrl->wLength);
 474
 475         /* composite driver infrastructure handles everything except
 476          * CDC class messages; interface activation uses set_alt().
 477          */
 478         switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
 479
 480         /* RNDIS uses the CDC command encapsulation mechanism to implement
 481          * an RPC scheme, with much getting/setting of attributes by OID.
 482          */
 483         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 484                         | USB_CDC_SEND_ENCAPSULATED_COMMAND:
 485                 if (w_value || w_index != rndis->ctrl_id)
 486                         goto invalid;
 487                 /* read the request; process it later */
 488                 value = w_length;
 489                 req->complete = rndis_command_complete;
 490                 req->context = rndis;
 491                 /* later, rndis_response_available() sends a notification */
 492                 break;
 493
 494         case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 495                         | USB_CDC_GET_ENCAPSULATED_RESPONSE:
 496                 if (w_value || w_index != rndis->ctrl_id)
 497                         goto invalid;
 498                 else {
 499                         u8 *buf;
 500                         u32 n;
 501
 502                         /* return the result */
 503                         buf = rndis_get_next_response(rndis->config, &n);
 504                         if (buf) {
 505                                 memcpy(req->buf, buf, n);
 506                                 req->complete = rndis_response_complete;
 507                                 req->context = rndis;
 508                                 rndis_free_response(rndis->config, buf);
 509                                 value = n;
 510                         }
 511                         /* else stalls ... spec says to avoid that */
 512                 }
 513                 break;
 514
 515         default:
 516 invalid:
 517                 VDBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
 518                         ctrl->bRequestType, ctrl->bRequest,
 519                         w_value, w_index, w_length);
 520         }
 521
 522         /* respond with data transfer or status phase? */
 523         if (value >= 0) {
 524                 DBG(cdev, "rndis req%02x.%02x v%04x i%04x l%d\n",
 525                         ctrl->bRequestType, ctrl->bRequest,
 526                         w_value, w_index, w_length);
 527                 req->zero = (value < w_length);
 528                 req->length = value;
 529                 value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 530                 if (value < 0)
 531                         ERROR(cdev, "rndis response on err %d\n", value);
 532         }
 533
 534         /* device either stalls (value < 0) or reports success */
 535         return value;
 536 }
 537
 538
 539 static int rndis_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 540 {
 541         struct f_rndis          *rndis = func_to_rndis(f);
 542         struct usb_composite_dev *cdev = f->config->cdev;
 543
 544         /* we know alt == 0 */
 545
 546         if (intf == rndis->ctrl_id) {
 547                 if (rndis->notify->driver_data) {
 548                         VDBG(cdev, "reset rndis control %d\n", intf);
 549                         usb_ep_disable(rndis->notify);
 550                 }
 551                 if (!rndis->notify->desc) {
 552                         VDBG(cdev, "init rndis ctrl %d\n", intf);
 553                         if (config_ep_by_speed(cdev->gadget, f, rndis->notify))
 554                                 goto fail;
 555                 }
 556                 usb_ep_enable(rndis->notify);
 557                 rndis->notify->driver_data = rndis;
 558
 559         } else if (intf == rndis->data_id) {
 560                 struct net_device       *net;
 561
 562                 if (rndis->port.in_ep->driver_data) {
 563                         DBG(cdev, "reset rndis\n");
 564                         gether_disconnect(&rndis->port);
 565                 }
 566
 567                 if (!rndis->port.in_ep->desc || !rndis->port.out_ep->desc) {
 568                         DBG(cdev, "init rndis\n");
 569                         if (config_ep_by_speed(cdev->gadget, f,
 570                                                rndis->port.in_ep) ||
 571                             config_ep_by_speed(cdev->gadget, f,
 572                                                rndis->port.out_ep)) {
 573                                 rndis->port.in_ep->desc = NULL;
 574                                 rndis->port.out_ep->desc = NULL;
 575                                 goto fail;
 576                         }
 577                 }
 578
 579                 /* Avoid ZLPs; they can be troublesome. */
 580                 rndis->port.is_zlp_ok = false;
 581
 582                 /* RNDIS should be in the "RNDIS uninitialized" state,
 583                  * either never activated or after rndis_uninit().
 584                  *
 585                  * We don't want data to flow here until a nonzero packet
 586                  * filter is set, at which point it enters "RNDIS data
 587                  * initialized" state ... but we do want the endpoints
 588                  * to be activated.  It's a strange little state.
 589                  *
 590                  * REVISIT the RNDIS gadget code has done this wrong for a
 591                  * very long time.  We need another call to the link layer
 592                  * code -- gether_updown(...bool) maybe -- to do it right.
 593                  */
 594                 rndis->port.cdc_filter = 0;
 595
 596                 DBG(cdev, "RNDIS RX/TX early activation ... \n");
 597                 net = gether_connect(&rndis->port);
 598                 if (IS_ERR(net))
 599                         return PTR_ERR(net);
 600
 601                 rndis_set_param_dev(rndis->config, net,
 602                                 &rndis->port.cdc_filter);
 603         } else
 604                 goto fail;
 605
 606         return 0;
 607 fail:
 608         return -EINVAL;
 609 }
 610
 611 static void rndis_disable(struct usb_function *f)
 612 {
 613         struct f_rndis          *rndis = func_to_rndis(f);
 614         struct usb_composite_dev *cdev = f->config->cdev;
 615
 616         if (!rndis->notify->driver_data)
 617                 return;
 618
 619         DBG(cdev, "rndis deactivated\n");
 620
 621         rndis_uninit(rndis->config);
 622         gether_disconnect(&rndis->port);
 623
 624         usb_ep_disable(rndis->notify);
 625         rndis->notify->driver_data = NULL;
 626 }
 627
 628 /*-------------------------------------------------------------------------*/
 629
 630 /*
 631  * This isn't quite the same mechanism as CDC Ethernet, since the
 632  * notification scheme passes less data, but the same set of link
 633  * states must be tested.  A key difference is that altsettings are
 634  * not used to tell whether the link should send packets or not.
 635  */
 636
 637 static void rndis_open(struct gether *geth)
 638 {
 639         struct f_rndis          *rndis = func_to_rndis(&geth->func);
 640         struct usb_composite_dev *cdev = geth->func.config->cdev;
 641
 642         DBG(cdev, "%s\n", __func__);
 643
 644         rndis_set_param_medium(rndis->config, RNDIS_MEDIUM_802_3,
 645                                 bitrate(cdev->gadget) / 100);
 646         rndis_signal_connect(rndis->config);
 647 }
 648
 649 static void rndis_close(struct gether *geth)
 650 {
 651         struct f_rndis          *rndis = func_to_rndis(&geth->func);
 652
 653         DBG(geth->func.config->cdev, "%s\n", __func__);
 654
 655         rndis_set_param_medium(rndis->config, RNDIS_MEDIUM_802_3, 0);
 656         rndis_signal_disconnect(rndis->config);
 657 }
 658
 659 /*-------------------------------------------------------------------------*/
 660
 661 /* Some controllers can't support RNDIS ... */
 662 static inline bool can_support_rndis(struct usb_configuration *c)
 663 {
 664         /* everything else is *presumably* fine */
 665         return true;
 666 }
 667
 668 /* ethernet function driver setup/binding */
 669
 670 static int
 671 rndis_bind(struct usb_configuration *c, struct usb_function *f)
 672 {
 673         struct usb_composite_dev *cdev = c->cdev;
 674         struct f_rndis          *rndis = func_to_rndis(f);
 675         struct usb_string       *us;
 676         int                     status;
 677         struct usb_ep           *ep;
 678
 679         struct f_rndis_opts *rndis_opts;
 680
 681         if (!can_support_rndis(c))
 682                 return -EINVAL;
 683
 684         rndis_opts = container_of(f->fi, struct f_rndis_opts, func_inst);
 685
 686         if (cdev->use_os_string) {
 687                 f->os_desc_table = kzalloc(sizeof(*f->os_desc_table),
 688                                            GFP_KERNEL);
 689                 if (!f->os_desc_table)
 690                         return PTR_ERR(f->os_desc_table);
 691                 f->os_desc_n = 1;
 692                 f->os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc;
 693         }
 694
 695         /*
 696          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
 697          * configurations are bound in sequence with list_for_each_entry,
 698          * in each configuration its functions are bound in sequence
 699          * with list_for_each_entry, so we assume no race condition
 700          * with regard to rndis_opts->bound access
 701          */
 702         if (!rndis_opts->bound) {
 703                 gether_set_gadget(rndis_opts->net, cdev->gadget);
 704                 status = gether_register_netdev(rndis_opts->net);
 705                 if (status)
 706                         goto fail;
 707                 rndis_opts->bound = true;
 708         }
 709
 710         us = usb_gstrings_attach(cdev, rndis_strings,
 711                                  ARRAY_SIZE(rndis_string_defs));
 712         if (IS_ERR(us)) {
 713                 status = PTR_ERR(us);
 714                 goto fail;
 715         }
 716         rndis_control_intf.iInterface = us[0].id;
 717         rndis_data_intf.iInterface = us[1].id;
 718         rndis_iad_descriptor.iFunction = us[2].id;
 719
 720         /* allocate instance-specific interface IDs */
 721         status = usb_interface_id(c, f);
 722         if (status < 0)
 723                 goto fail;
 724         rndis->ctrl_id = status;
 725         rndis_iad_descriptor.bFirstInterface = status;
 726
 727         rndis_control_intf.bInterfaceNumber = status;
 728         rndis_union_desc.bMasterInterface0 = status;
 729
 730         status = usb_interface_id(c, f);
 731         if (status < 0)
 732                 goto fail;
 733         rndis->data_id = status;
 734
 735         rndis_data_intf.bInterfaceNumber = status;
 736         rndis_union_desc.bSlaveInterface0 = status;
 737
 738         status = -ENODEV;
 739
 740         /* allocate instance-specific endpoints */
 741         ep = usb_ep_autoconfig(cdev->gadget, &fs_in_desc);
 742         if (!ep)
 743                 goto fail;
 744         rndis->port.in_ep = ep;
 745         ep->driver_data = cdev; /* claim */
 746
 747         ep = usb_ep_autoconfig(cdev->gadget, &fs_out_desc);
 748         if (!ep)
 749                 goto fail;
 750         rndis->port.out_ep = ep;
 751         ep->driver_data = cdev; /* claim */
 752
 753         /* NOTE:  a status/notification endpoint is, strictly speaking,
 754          * optional.  We don't treat it that way though!  It's simpler,
 755          * and some newer profiles don't treat it as optional.
 756          */
 757         ep = usb_ep_autoconfig(cdev->gadget, &fs_notify_desc);
 758         if (!ep)
 759                 goto fail;
 760         rndis->notify = ep;
 761         ep->driver_data = cdev; /* claim */
 762
 763         status = -ENOMEM;
 764
 765         /* allocate notification request and buffer */
 766         rndis->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL);
 767         if (!rndis->notify_req)
 768                 goto fail;
 769         rndis->notify_req->buf = kmalloc(STATUS_BYTECOUNT, GFP_KERNEL);
 770         if (!rndis->notify_req->buf)
 771                 goto fail;
 772         rndis->notify_req->length = STATUS_BYTECOUNT;
 773         rndis->notify_req->context = rndis;
 774         rndis->notify_req->complete = rndis_response_complete;
 775
 776         /* support all relevant hardware speeds... we expect that when
 777          * hardware is dual speed, all bulk-capable endpoints work at
 778          * both speeds
 779          */
 780         hs_in_desc.bEndpointAddress = fs_in_desc.bEndpointAddress;
 781         hs_out_desc.bEndpointAddress = fs_out_desc.bEndpointAddress;
 782         hs_notify_desc.bEndpointAddress = fs_notify_desc.bEndpointAddress;
 783
 784         ss_in_desc.bEndpointAddress = fs_in_desc.bEndpointAddress;
 785         ss_out_desc.bEndpointAddress = fs_out_desc.bEndpointAddress;
 786         ss_notify_desc.bEndpointAddress = fs_notify_desc.bEndpointAddress;
 787
 788         status = usb_assign_descriptors(f, eth_fs_function, eth_hs_function,
 789                         eth_ss_function);
 790         if (status)
 791                 goto fail;
 792
 793         rndis->port.open = rndis_open;
 794         rndis->port.close = rndis_close;
 795
 796         rndis_set_param_medium(rndis->config, RNDIS_MEDIUM_802_3, 0);
 797         rndis_set_host_mac(rndis->config, rndis->ethaddr);
 798
 799         if (rndis->manufacturer && rndis->vendorID &&
 800                         rndis_set_param_vendor(rndis->config, rndis->vendorID,
 801                                                rndis->manufacturer))
 802                 goto fail;
 803
 804         /* NOTE:  all that is done without knowing or caring about
 805          * the network link ... which is unavailable to this code
 806          * until we're activated via set_alt().
 807          */
 808
 809         DBG(cdev, "RNDIS: %s speed IN/%s OUT/%s NOTIFY/%s\n",
 810                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 811                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 812                         rndis->port.in_ep->name, rndis->port.out_ep->name,
 813                         rndis->notify->name);
 814         return 0;
 815
 816 fail:
 817         kfree(f->os_desc_table);
 818         f->os_desc_n = 0;
 819         usb_free_all_descriptors(f);
 820
 821         if (rndis->notify_req) {
 822                 kfree(rndis->notify_req->buf);
 823                 usb_ep_free_request(rndis->notify, rndis->notify_req);
 824         }
 825
 826         /* we might as well release our claims on endpoints */
 827         if (rndis->notify)
 828                 rndis->notify->driver_data = NULL;
 829         if (rndis->port.out_ep)
 830                 rndis->port.out_ep->driver_data = NULL;
 831         if (rndis->port.in_ep)
 832                 rndis->port.in_ep->driver_data = NULL;
 833
 834         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 835
 836         return status;
 837 }
 838
 839 void rndis_borrow_net(struct usb_function_instance *f, struct net_device *net)
 840 {
 841         struct f_rndis_opts *opts;
 842
 843         opts = container_of(f, struct f_rndis_opts, func_inst);
 844         if (opts->bound)
 845                 gether_cleanup(netdev_priv(opts->net));
 846         else
 847                 free_netdev(opts->net);
 848         opts->borrowed_net = opts->bound = true;
 849         opts->net = net;
 850 }
 851 EXPORT_SYMBOL_GPL(rndis_borrow_net);
 852
 853 static inline struct f_rndis_opts *to_f_rndis_opts(struct config_item *item)
 854 {
 855         return container_of(to_config_group(item), struct f_rndis_opts,
 856                             func_inst.group);
 857 }
 858
 859 /* f_rndis_item_ops */
 860 USB_ETHERNET_CONFIGFS_ITEM(rndis);
 861
 862 /* f_rndis_opts_dev_addr */
 863 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(rndis);
 864
 865 /* f_rndis_opts_host_addr */
 866 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(rndis);
 867
 868 /* f_rndis_opts_qmult */
 869 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(rndis);
 870
 871 /* f_rndis_opts_ifname */
 872 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(rndis);
 873
 874 static struct configfs_attribute *rndis_attrs[] = {
 875         &f_rndis_opts_dev_addr.attr,
 876         &f_rndis_opts_host_addr.attr,
 877         &f_rndis_opts_qmult.attr,
 878         &f_rndis_opts_ifname.attr,
 879         NULL,
 880 };
 881
 882 static struct config_item_type rndis_func_type = {
 883         .ct_item_ops    = &rndis_item_ops,
 884         .ct_attrs       = rndis_attrs,
 885         .ct_owner       = THIS_MODULE,
 886 };
 887
 888 static void rndis_free_inst(struct usb_function_instance *f)
 889 {
 890         struct f_rndis_opts *opts;
 891
 892         opts = container_of(f, struct f_rndis_opts, func_inst);
 893         if (!opts->borrowed_net) {
 894                 if (opts->bound)
 895                         gether_cleanup(netdev_priv(opts->net));
 896                 else
 897                         free_netdev(opts->net);
 898         }
 899
 900         kfree(opts->rndis_os_desc.group.default_groups); /* single VLA chunk */
 901         kfree(opts);
 902 }
 903
 904 static struct usb_function_instance *rndis_alloc_inst(void)
 905 {
 906         struct f_rndis_opts *opts;
 907         struct usb_os_desc *descs[1];
 908
 909         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 910         if (!opts)
 911                 return ERR_PTR(-ENOMEM);
 912         opts->rndis_os_desc.ext_compat_id = opts->rndis_ext_compat_id;
 913
 914         mutex_init(&opts->lock);
 915         opts->func_inst.free_func_inst = rndis_free_inst;
 916         opts->net = gether_setup_default();
 917         if (IS_ERR(opts->net)) {
 918                 struct net_device *net = opts->net;
 919                 kfree(opts);
 920                 return ERR_CAST(net);
 921         }
 922         INIT_LIST_HEAD(&opts->rndis_os_desc.ext_prop);
 923
 924         descs[0] = &opts->rndis_os_desc;
 925         usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs,
 926                                        THIS_MODULE);
 927         config_group_init_type_name(&opts->func_inst.group, "",
 928                                     &rndis_func_type);
 929
 930         return &opts->func_inst;
 931 }
 932
 933 static void rndis_free(struct usb_function *f)
 934 {
 935         struct f_rndis *rndis;
 936         struct f_rndis_opts *opts;
 937
 938         rndis = func_to_rndis(f);
 939         rndis_deregister(rndis->config);
 940         opts = container_of(f->fi, struct f_rndis_opts, func_inst);
 941         kfree(rndis);
 942         mutex_lock(&opts->lock);
 943         opts->refcnt--;
 944         mutex_unlock(&opts->lock);
 945 }
 946
 947 static void rndis_unbind(struct usb_configuration *c, struct usb_function *f)
 948 {
 949         struct f_rndis          *rndis = func_to_rndis(f);
 950
 951         kfree(f->os_desc_table);
 952         f->os_desc_n = 0;
 953         usb_free_all_descriptors(f);
 954
 955         kfree(rndis->notify_req->buf);
 956         usb_ep_free_request(rndis->notify, rndis->notify_req);
 957 }
 958
 959 static struct usb_function *rndis_alloc(struct usb_function_instance *fi)
 960 {
 961         struct f_rndis  *rndis;
 962         struct f_rndis_opts *opts;
 963         int status;
 964
 965         /* allocate and initialize one new instance */
 966         rndis = kzalloc(sizeof(*rndis), GFP_KERNEL);
 967         if (!rndis)
 968                 return ERR_PTR(-ENOMEM);
 969
 970         opts = container_of(fi, struct f_rndis_opts, func_inst);
 971         mutex_lock(&opts->lock);
 972         opts->refcnt++;
 973
 974         gether_get_host_addr_u8(opts->net, rndis->ethaddr);
 975         rndis->vendorID = opts->vendor_id;
 976         rndis->manufacturer = opts->manufacturer;
 977
 978         rndis->port.ioport = netdev_priv(opts->net);
 979         mutex_unlock(&opts->lock);
 980         /* RNDIS activates when the host changes this filter */
 981         rndis->port.cdc_filter = 0;
 982
 983         /* RNDIS has special (and complex) framing */
 984         rndis->port.header_len = sizeof(struct rndis_packet_msg_type);
 985         rndis->port.wrap = rndis_add_header;
 986         rndis->port.unwrap = rndis_rm_hdr;
 987
 988         rndis->port.func.name = "rndis";
 989         /* descriptors are per-instance copies */
 990         rndis->port.func.bind = rndis_bind;
 991         rndis->port.func.unbind = rndis_unbind;
 992         rndis->port.func.set_alt = rndis_set_alt;
 993         rndis->port.func.setup = rndis_setup;
 994         rndis->port.func.disable = rndis_disable;
 995         rndis->port.func.free_func = rndis_free;
 996
 997         status = rndis_register(rndis_response_available, rndis);
 998         if (status < 0) {
 999                 kfree(rndis);
1000                 return ERR_PTR(status);
1001         }
1002         rndis->config = status;
1003
1004         return &rndis->port.func;
1005 }
1006
1007 DECLARE_USB_FUNCTION(rndis, rndis_alloc_inst, rndis_alloc);
1008
1009 static int __init rndis_mod_init(void)
1010 {
1011         int ret;
1012
1013         ret = rndis_init();
1014         if (ret)
1015                 return ret;
1016
1017         return usb_function_register(&rndisusb_func);
1018 }
1019 module_init(rndis_mod_init);
1020
1021 static void __exit rndis_mod_exit(void)
1022 {
1023         usb_function_unregister(&rndisusb_func);
1024         rndis_exit();
1025 }
1026 module_exit(rndis_mod_exit);
1027
1028 MODULE_LICENSE("GPL");
1029 MODULE_AUTHOR("David Brownell");