drivers/usb/gadget/function/f_rndis.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * f_rndis.c -- RNDIS link function driver
   4  *
   5  * Copyright (C) 2003-2005,2008 David Brownell
   6  * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger
   7  * Copyright (C) 2008 Nokia Corporation
   8  * Copyright (C) 2009 Samsung Electronics
   9  *                    Author: Michal Nazarewicz (mina86@mina86.com)
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  */
  16
  17 /* #define VERBOSE_DEBUG */
  18
  19 #include <linux/slab.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/device.h>
  23 #include <linux/etherdevice.h>
  24
  25 #include <linux/atomic.h>
  26
  27 #include "u_ether.h"
  28 #include "u_ether_configfs.h"
  29 #include "u_rndis.h"
  30 #include "rndis.h"
  31 #include "configfs.h"
  32
  33 /*
  34  * This function is an RNDIS Ethernet port -- a Microsoft protocol that's
  35  * been promoted instead of the standard CDC Ethernet.  The published RNDIS
  36  * spec is ambiguous, incomplete, and needlessly complex.  Variants such as
  37  * ActiveSync have even worse status in terms of specification.
  38  *
  39  * In short:  it's a protocol controlled by (and for) Microsoft, not for an
  40  * Open ecosystem or markets.  Linux supports it *only* because Microsoft
  41  * doesn't support the CDC Ethernet standard.
  42  *
  43  * The RNDIS data transfer model is complex, with multiple Ethernet packets
  44  * per USB message, and out of band data.  The control model is built around
  45  * what's essentially an "RNDIS RPC" protocol.  It's all wrapped in a CDC ACM
  46  * (modem, not Ethernet) veneer, with those ACM descriptors being entirely
  47  * useless (they're ignored).  RNDIS expects to be the only function in its
  48  * configuration, so it's no real help if you need composite devices; and
  49  * it expects to be the first configuration too.
  50  *
  51  * There is a single technical advantage of RNDIS over CDC Ethernet, if you
  52  * discount the fluff that its RPC can be made to deliver: it doesn't need
  53  * a NOP altsetting for the data interface.  That lets it work on some of the
  54  * "so smart it's stupid" hardware which takes over configuration changes
  55  * from the software, and adds restrictions like "no altsettings".
  56  *
  57  * Unfortunately MSFT's RNDIS drivers are buggy.  They hang or oops, and
  58  * have all sorts of contrary-to-specification oddities that can prevent
  59  * them from working sanely.  Since bugfixes (or accurate specs, letting
  60  * Linux work around those bugs) are unlikely to ever come from MSFT, you
  61  * may want to avoid using RNDIS on purely operational grounds.
  62  *
  63  * Omissions from the RNDIS 1.0 specification include:
  64  *
  65  *   - Power management ... references data that's scattered around lots
  66  *     of other documentation, which is incorrect/incomplete there too.
  67  *
  68  *   - There are various undocumented protocol requirements, like the need
  69  *     to send garbage in some control-OUT messages.
  70  *
  71  *   - MS-Windows drivers sometimes emit undocumented requests.
  72  */
  73
  74 struct f_rndis {
  75         struct gether                   port;
  76         u8                              ctrl_id, data_id;
  77         u8                              ethaddr[ETH_ALEN];
  78         u32                             vendorID;
  79         const char                      *manufacturer;
  80         struct rndis_params             *params;
  81
  82         struct usb_ep                   *notify;
  83         struct usb_request              *notify_req;
  84         atomic_t                        notify_count;
  85 };
  86
  87 static inline struct f_rndis *func_to_rndis(struct usb_function *f)
  88 {
  89         return container_of(f, struct f_rndis, port.func);
  90 }
  91
  92 /* peak (theoretical) bulk transfer rate in bits-per-second */
  93 static unsigned int bitrate(struct usb_gadget *g)
  94 {
  95         if (gadget_is_superspeed(g) && g->speed == USB_SPEED_SUPER)
  96                 return 13 * 1024 * 8 * 1000 * 8;
  97         else if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
  98                 return 13 * 512 * 8 * 1000 * 8;
  99         else
 100                 return 19 * 64 * 1 * 1000 * 8;
 101 }
 102
 103 /*-------------------------------------------------------------------------*/
 104
 105 /*
 106  */
 107
 108 #define RNDIS_STATUS_INTERVAL_MS        32
 109 #define STATUS_BYTECOUNT                8       /* 8 bytes data */
 110
 111
 112 /* interface descriptor: */
 113
 114 static struct usb_interface_descriptor rndis_control_intf = {
 115         .bLength =              sizeof rndis_control_intf,
 116         .bDescriptorType =      USB_DT_INTERFACE,
 117
 118         /* .bInterfaceNumber = DYNAMIC */
 119         /* status endpoint is optional; this could be patched later */
 120         .bNumEndpoints =        1,
 121         .bInterfaceClass =      USB_CLASS_COMM,
 122         .bInterfaceSubClass =   USB_CDC_SUBCLASS_ACM,
 123         .bInterfaceProtocol =   USB_CDC_ACM_PROTO_VENDOR,
 124         /* .iInterface = DYNAMIC */
 125 };
 126
 127 static struct usb_cdc_header_desc header_desc = {
 128         .bLength =              sizeof header_desc,
 129         .bDescriptorType =      USB_DT_CS_INTERFACE,
 130         .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
 131
 132         .bcdCDC =               cpu_to_le16(0x0110),
 133 };
 134
 135 static struct usb_cdc_call_mgmt_descriptor call_mgmt_descriptor = {
 136         .bLength =              sizeof call_mgmt_descriptor,
 137         .bDescriptorType =      USB_DT_CS_INTERFACE,
 138         .bDescriptorSubType =   USB_CDC_CALL_MANAGEMENT_TYPE,
 139
 140         .bmCapabilities =       0x00,
 141         .bDataInterface =       0x01,
 142 };
 143
 144 static struct usb_cdc_acm_descriptor rndis_acm_descriptor = {
 145         .bLength =              sizeof rndis_acm_descriptor,
 146         .bDescriptorType =      USB_DT_CS_INTERFACE,
 147         .bDescriptorSubType =   USB_CDC_ACM_TYPE,
 148
 149         .bmCapabilities =       0x00,
 150 };
 151
 152 static struct usb_cdc_union_desc rndis_union_desc = {
 153         .bLength =              sizeof(rndis_union_desc),
 154         .bDescriptorType =      USB_DT_CS_INTERFACE,
 155         .bDescriptorSubType =   USB_CDC_UNION_TYPE,
 156         /* .bMasterInterface0 = DYNAMIC */
 157         /* .bSlaveInterface0 =  DYNAMIC */
 158 };
 159
 160 /* the data interface has two bulk endpoints */
 161
 162 static struct usb_interface_descriptor rndis_data_intf = {
 163         .bLength =              sizeof rndis_data_intf,
 164         .bDescriptorType =      USB_DT_INTERFACE,
 165
 166         /* .bInterfaceNumber = DYNAMIC */
 167         .bNumEndpoints =        2,
 168         .bInterfaceClass =      USB_CLASS_CDC_DATA,
 169         .bInterfaceSubClass =   0,
 170         .bInterfaceProtocol =   0,
 171         /* .iInterface = DYNAMIC */
 172 };
 173
 174
 175 static struct usb_interface_assoc_descriptor
 176 rndis_iad_descriptor = {
 177         .bLength =              sizeof rndis_iad_descriptor,
 178         .bDescriptorType =      USB_DT_INTERFACE_ASSOCIATION,
 179
 180         .bFirstInterface =      0, /* XXX, hardcoded */
 181         .bInterfaceCount =      2,      // control + data
 182         .bFunctionClass =       USB_CLASS_COMM,
 183         .bFunctionSubClass =    USB_CDC_SUBCLASS_ETHERNET,
 184         .bFunctionProtocol =    USB_CDC_PROTO_NONE,
 185         /* .iFunction = DYNAMIC */
 186 };
 187
 188 /* full speed support: */
 189
 190 static struct usb_endpoint_descriptor fs_notify_desc = {
 191         .bLength =              USB_DT_ENDPOINT_SIZE,
 192         .bDescriptorType =      USB_DT_ENDPOINT,
 193
 194         .bEndpointAddress =     USB_DIR_IN,
 195         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 196         .wMaxPacketSize =       cpu_to_le16(STATUS_BYTECOUNT),
 197         .bInterval =            RNDIS_STATUS_INTERVAL_MS,
 198 };
 199
 200 static struct usb_endpoint_descriptor fs_in_desc = {
 201         .bLength =              USB_DT_ENDPOINT_SIZE,
 202         .bDescriptorType =      USB_DT_ENDPOINT,
 203
 204         .bEndpointAddress =     USB_DIR_IN,
 205         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 206 };
 207
 208 static struct usb_endpoint_descriptor fs_out_desc = {
 209         .bLength =              USB_DT_ENDPOINT_SIZE,
 210         .bDescriptorType =      USB_DT_ENDPOINT,
 211
 212         .bEndpointAddress =     USB_DIR_OUT,
 213         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 214 };
 215
 216 static struct usb_descriptor_header *eth_fs_function[] = {
 217         (struct usb_descriptor_header *) &rndis_iad_descriptor,
 218
 219         /* control interface matches ACM, not Ethernet */
 220         (struct usb_descriptor_header *) &rndis_control_intf,
 221         (struct usb_descriptor_header *) &header_desc,
 222         (struct usb_descriptor_header *) &call_mgmt_descriptor,
 223         (struct usb_descriptor_header *) &rndis_acm_descriptor,
 224         (struct usb_descriptor_header *) &rndis_union_desc,
 225         (struct usb_descriptor_header *) &fs_notify_desc,
 226
 227         /* data interface has no altsetting */
 228         (struct usb_descriptor_header *) &rndis_data_intf,
 229         (struct usb_descriptor_header *) &fs_in_desc,
 230         (struct usb_descriptor_header *) &fs_out_desc,
 231         NULL,
 232 };
 233
 234 /* high speed support: */
 235
 236 static struct usb_endpoint_descriptor hs_notify_desc = {
 237         .bLength =              USB_DT_ENDPOINT_SIZE,
 238         .bDescriptorType =      USB_DT_ENDPOINT,
 239
 240         .bEndpointAddress =     USB_DIR_IN,
 241         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 242         .wMaxPacketSize =       cpu_to_le16(STATUS_BYTECOUNT),
 243         .bInterval =            USB_MS_TO_HS_INTERVAL(RNDIS_STATUS_INTERVAL_MS)
 244 };
 245
 246 static struct usb_endpoint_descriptor hs_in_desc = {
 247         .bLength =              USB_DT_ENDPOINT_SIZE,
 248         .bDescriptorType =      USB_DT_ENDPOINT,
 249
 250         .bEndpointAddress =     USB_DIR_IN,
 251         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 252         .wMaxPacketSize =       cpu_to_le16(512),
 253 };
 254
 255 static struct usb_endpoint_descriptor hs_out_desc = {
 256         .bLength =              USB_DT_ENDPOINT_SIZE,
 257         .bDescriptorType =      USB_DT_ENDPOINT,
 258
 259         .bEndpointAddress =     USB_DIR_OUT,
 260         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 261         .wMaxPacketSize =       cpu_to_le16(512),
 262 };
 263
 264 static struct usb_descriptor_header *eth_hs_function[] = {
 265         (struct usb_descriptor_header *) &rndis_iad_descriptor,
 266
 267         /* control interface matches ACM, not Ethernet */
 268         (struct usb_descriptor_header *) &rndis_control_intf,
 269         (struct usb_descriptor_header *) &header_desc,
 270         (struct usb_descriptor_header *) &call_mgmt_descriptor,
 271         (struct usb_descriptor_header *) &rndis_acm_descriptor,
 272         (struct usb_descriptor_header *) &rndis_union_desc,
 273         (struct usb_descriptor_header *) &hs_notify_desc,
 274
 275         /* data interface has no altsetting */
 276         (struct usb_descriptor_header *) &rndis_data_intf,
 277         (struct usb_descriptor_header *) &hs_in_desc,
 278         (struct usb_descriptor_header *) &hs_out_desc,
 279         NULL,
 280 };
 281
 282 /* super speed support: */
 283
 284 static struct usb_endpoint_descriptor ss_notify_desc = {
 285         .bLength =              USB_DT_ENDPOINT_SIZE,
 286         .bDescriptorType =      USB_DT_ENDPOINT,
 287
 288         .bEndpointAddress =     USB_DIR_IN,
 289         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 290         .wMaxPacketSize =       cpu_to_le16(STATUS_BYTECOUNT),
 291         .bInterval =            USB_MS_TO_HS_INTERVAL(RNDIS_STATUS_INTERVAL_MS)
 292 };
 293
 294 static struct usb_ss_ep_comp_descriptor ss_intr_comp_desc = {
 295         .bLength =              sizeof ss_intr_comp_desc,
 296         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 297
 298         /* the following 3 values can be tweaked if necessary */
 299         /* .bMaxBurst =         0, */
 300         /* .bmAttributes =      0, */
 301         .wBytesPerInterval =    cpu_to_le16(STATUS_BYTECOUNT),
 302 };
 303
 304 static struct usb_endpoint_descriptor ss_in_desc = {
 305         .bLength =              USB_DT_ENDPOINT_SIZE,
 306         .bDescriptorType =      USB_DT_ENDPOINT,
 307
 308         .bEndpointAddress =     USB_DIR_IN,
 309         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 310         .wMaxPacketSize =       cpu_to_le16(1024),
 311 };
 312
 313 static struct usb_endpoint_descriptor ss_out_desc = {
 314         .bLength =              USB_DT_ENDPOINT_SIZE,
 315         .bDescriptorType =      USB_DT_ENDPOINT,
 316
 317         .bEndpointAddress =     USB_DIR_OUT,
 318         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 319         .wMaxPacketSize =       cpu_to_le16(1024),
 320 };
 321
 322 static struct usb_ss_ep_comp_descriptor ss_bulk_comp_desc = {
 323         .bLength =              sizeof ss_bulk_comp_desc,
 324         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 325
 326         /* the following 2 values can be tweaked if necessary */
 327         /* .bMaxBurst =         0, */
 328         /* .bmAttributes =      0, */
 329 };
 330
 331 static struct usb_descriptor_header *eth_ss_function[] = {
 332         (struct usb_descriptor_header *) &rndis_iad_descriptor,
 333
 334         /* control interface matches ACM, not Ethernet */
 335         (struct usb_descriptor_header *) &rndis_control_intf,
 336         (struct usb_descriptor_header *) &header_desc,
 337         (struct usb_descriptor_header *) &call_mgmt_descriptor,
 338         (struct usb_descriptor_header *) &rndis_acm_descriptor,
 339         (struct usb_descriptor_header *) &rndis_union_desc,
 340         (struct usb_descriptor_header *) &ss_notify_desc,
 341         (struct usb_descriptor_header *) &ss_intr_comp_desc,
 342
 343         /* data interface has no altsetting */
 344         (struct usb_descriptor_header *) &rndis_data_intf,
 345         (struct usb_descriptor_header *) &ss_in_desc,
 346         (struct usb_descriptor_header *) &ss_bulk_comp_desc,
 347         (struct usb_descriptor_header *) &ss_out_desc,
 348         (struct usb_descriptor_header *) &ss_bulk_comp_desc,
 349         NULL,
 350 };
 351
 352 /* string descriptors: */
 353
 354 static struct usb_string rndis_string_defs[] = {
 355         [0].s = "RNDIS Communications Control",
 356         [1].s = "RNDIS Ethernet Data",
 357         [2].s = "RNDIS",
 358         {  } /* end of list */
 359 };
 360
 361 static struct usb_gadget_strings rndis_string_table = {
 362         .language =             0x0409, /* en-us */
 363         .strings =              rndis_string_defs,
 364 };
 365
 366 static struct usb_gadget_strings *rndis_strings[] = {
 367         &rndis_string_table,
 368         NULL,
 369 };
 370
 371 /*-------------------------------------------------------------------------*/
 372
 373 static struct sk_buff *rndis_add_header(struct gether *port,
 374                                         struct sk_buff *skb)
 375 {
 376         struct sk_buff *skb2;
 377
 378         if (!skb)
 379                 return NULL;
 380
 381         skb2 = skb_realloc_headroom(skb, sizeof(struct rndis_packet_msg_type));
 382         rndis_add_hdr(skb2);
 383
 384         dev_kfree_skb(skb);
 385         return skb2;
 386 }
 387
 388 static void rndis_response_available(void *_rndis)
 389 {
 390         struct f_rndis                  *rndis = _rndis;
 391         struct usb_request              *req = rndis->notify_req;
 392         struct usb_composite_dev        *cdev = rndis->port.func.config->cdev;
 393         __le32                          *data = req->buf;
 394         int                             status;
 395
 396         if (atomic_inc_return(&rndis->notify_count) != 1)
 397                 return;
 398
 399         /* Send RNDIS RESPONSE_AVAILABLE notification; a
 400          * USB_CDC_NOTIFY_RESPONSE_AVAILABLE "should" work too
 401          *
 402          * This is the only notification defined by RNDIS.
 403          */
 404         data[0] = cpu_to_le32(1);
 405         data[1] = cpu_to_le32(0);
 406
 407         status = usb_ep_queue(rndis->notify, req, GFP_ATOMIC);
 408         if (status) {
 409                 atomic_dec(&rndis->notify_count);
 410                 DBG(cdev, "notify/0 --> %d\n", status);
 411         }
 412 }
 413
 414 static void rndis_response_complete(struct usb_ep *ep, struct usb_request *req)
 415 {
 416         struct f_rndis                  *rndis = req->context;
 417         struct usb_composite_dev        *cdev = rndis->port.func.config->cdev;
 418         int                             status = req->status;
 419
 420         /* after TX:
 421          *  - USB_CDC_GET_ENCAPSULATED_RESPONSE (ep0/control)
 422          *  - RNDIS_RESPONSE_AVAILABLE (status/irq)
 423          */
 424         switch (status) {
 425         case -ECONNRESET:
 426         case -ESHUTDOWN:
 427                 /* connection gone */
 428                 atomic_set(&rndis->notify_count, 0);
 429                 break;
 430         default:
 431                 DBG(cdev, "RNDIS %s response error %d, %d/%d\n",
 432                         ep->name, status,
 433                         req->actual, req->length);
 434                 /* FALLTHROUGH */
 435         case 0:
 436                 if (ep != rndis->notify)
 437                         break;
 438
 439                 /* handle multiple pending RNDIS_RESPONSE_AVAILABLE
 440                  * notifications by resending until we're done
 441                  */
 442                 if (atomic_dec_and_test(&rndis->notify_count))
 443                         break;
 444                 status = usb_ep_queue(rndis->notify, req, GFP_ATOMIC);
 445                 if (status) {
 446                         atomic_dec(&rndis->notify_count);
 447                         DBG(cdev, "notify/1 --> %d\n", status);
 448                 }
 449                 break;
 450         }
 451 }
 452
 453 static void rndis_command_complete(struct usb_ep *ep, struct usb_request *req)
 454 {
 455         struct f_rndis                  *rndis = req->context;
 456         int                             status;
 457
 458         /* received RNDIS command from USB_CDC_SEND_ENCAPSULATED_COMMAND */
 459 //      spin_lock(&dev->lock);
 460         status = rndis_msg_parser(rndis->params, (u8 *) req->buf);
 461         if (status < 0)
 462                 pr_err("RNDIS command error %d, %d/%d\n",
 463                         status, req->actual, req->length);
 464 //      spin_unlock(&dev->lock);
 465 }
 466
 467 static int
 468 rndis_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 469 {
 470         struct f_rndis          *rndis = func_to_rndis(f);
 471         struct usb_composite_dev *cdev = f->config->cdev;
 472         struct usb_request      *req = cdev->req;
 473         int                     value = -EOPNOTSUPP;
 474         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 475         u16                     w_value = le16_to_cpu(ctrl->wValue);
 476         u16                     w_length = le16_to_cpu(ctrl->wLength);
 477
 478         /* composite driver infrastructure handles everything except
 479          * CDC class messages; interface activation uses set_alt().
 480          */
 481         switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
 482
 483         /* RNDIS uses the CDC command encapsulation mechanism to implement
 484          * an RPC scheme, with much getting/setting of attributes by OID.
 485          */
 486         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 487                         | USB_CDC_SEND_ENCAPSULATED_COMMAND:
 488                 if (w_value || w_index != rndis->ctrl_id)
 489                         goto invalid;
 490                 /* read the request; process it later */
 491                 value = w_length;
 492                 req->complete = rndis_command_complete;
 493                 req->context = rndis;
 494                 /* later, rndis_response_available() sends a notification */
 495                 break;
 496
 497         case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 498                         | USB_CDC_GET_ENCAPSULATED_RESPONSE:
 499                 if (w_value || w_index != rndis->ctrl_id)
 500                         goto invalid;
 501                 else {
 502                         u8 *buf;
 503                         u32 n;
 504
 505                         /* return the result */
 506                         buf = rndis_get_next_response(rndis->params, &n);
 507                         if (buf) {
 508                                 memcpy(req->buf, buf, n);
 509                                 req->complete = rndis_response_complete;
 510                                 req->context = rndis;
 511                                 rndis_free_response(rndis->params, buf);
 512                                 value = n;
 513                         }
 514                         /* else stalls ... spec says to avoid that */
 515                 }
 516                 break;
 517
 518         default:
 519 invalid:
 520                 VDBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
 521                         ctrl->bRequestType, ctrl->bRequest,
 522                         w_value, w_index, w_length);
 523         }
 524
 525         /* respond with data transfer or status phase? */
 526         if (value >= 0) {
 527                 DBG(cdev, "rndis req%02x.%02x v%04x i%04x l%d\n",
 528                         ctrl->bRequestType, ctrl->bRequest,
 529                         w_value, w_index, w_length);
 530                 req->zero = (value < w_length);
 531                 req->length = value;
 532                 value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 533                 if (value < 0)
 534                         ERROR(cdev, "rndis response on err %d\n", value);
 535         }
 536
 537         /* device either stalls (value < 0) or reports success */
 538         return value;
 539 }
 540
 541
 542 static int rndis_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 543 {
 544         struct f_rndis          *rndis = func_to_rndis(f);
 545         struct usb_composite_dev *cdev = f->config->cdev;
 546
 547         /* we know alt == 0 */
 548
 549         if (intf == rndis->ctrl_id) {
 550                 VDBG(cdev, "reset rndis control %d\n", intf);
 551                 usb_ep_disable(rndis->notify);
 552
 553                 if (!rndis->notify->desc) {
 554                         VDBG(cdev, "init rndis ctrl %d\n", intf);
 555                         if (config_ep_by_speed(cdev->gadget, f, rndis->notify))
 556                                 goto fail;
 557                 }
 558                 usb_ep_enable(rndis->notify);
 559
 560         } else if (intf == rndis->data_id) {
 561                 struct net_device       *net;
 562
 563                 if (rndis->port.in_ep->enabled) {
 564                         DBG(cdev, "reset rndis\n");
 565                         gether_disconnect(&rndis->port);
 566                 }
 567
 568                 if (!rndis->port.in_ep->desc || !rndis->port.out_ep->desc) {
 569                         DBG(cdev, "init rndis\n");
 570                         if (config_ep_by_speed(cdev->gadget, f,
 571                                                rndis->port.in_ep) ||
 572                             config_ep_by_speed(cdev->gadget, f,
 573                                                rndis->port.out_ep)) {
 574                                 rndis->port.in_ep->desc = NULL;
 575                                 rndis->port.out_ep->desc = NULL;
 576                                 goto fail;
 577                         }
 578                 }
 579
 580                 /* Avoid ZLPs; they can be troublesome. */
 581                 rndis->port.is_zlp_ok = false;
 582
 583                 /* RNDIS should be in the "RNDIS uninitialized" state,
 584                  * either never activated or after rndis_uninit().
 585                  *
 586                  * We don't want data to flow here until a nonzero packet
 587                  * filter is set, at which point it enters "RNDIS data
 588                  * initialized" state ... but we do want the endpoints
 589                  * to be activated.  It's a strange little state.
 590                  *
 591                  * REVISIT the RNDIS gadget code has done this wrong for a
 592                  * very long time.  We need another call to the link layer
 593                  * code -- gether_updown(...bool) maybe -- to do it right.
 594                  */
 595                 rndis->port.cdc_filter = 0;
 596
 597                 DBG(cdev, "RNDIS RX/TX early activation ... \n");
 598                 net = gether_connect(&rndis->port);
 599                 if (IS_ERR(net))
 600                         return PTR_ERR(net);
 601
 602                 rndis_set_param_dev(rndis->params, net,
 603                                 &rndis->port.cdc_filter);
 604         } else
 605                 goto fail;
 606
 607         return 0;
 608 fail:
 609         return -EINVAL;
 610 }
 611
 612 static void rndis_disable(struct usb_function *f)
 613 {
 614         struct f_rndis          *rndis = func_to_rndis(f);
 615         struct usb_composite_dev *cdev = f->config->cdev;
 616
 617         if (!rndis->notify->enabled)
 618                 return;
 619
 620         DBG(cdev, "rndis deactivated\n");
 621
 622         rndis_uninit(rndis->params);
 623         gether_disconnect(&rndis->port);
 624
 625         usb_ep_disable(rndis->notify);
 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->params, RNDIS_MEDIUM_802_3,
 645                                 bitrate(cdev->gadget) / 100);
 646         rndis_signal_connect(rndis->params);
 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->params, RNDIS_MEDIUM_802_3, 0);
 656         rndis_signal_disconnect(rndis->params);
 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 -ENOMEM;
 691                 f->os_desc_n = 1;
 692                 f->os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc;
 693         }
 694
 695         rndis_iad_descriptor.bFunctionClass = rndis_opts->class;
 696         rndis_iad_descriptor.bFunctionSubClass = rndis_opts->subclass;
 697         rndis_iad_descriptor.bFunctionProtocol = rndis_opts->protocol;
 698
 699         /*
 700          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
 701          * configurations are bound in sequence with list_for_each_entry,
 702          * in each configuration its functions are bound in sequence
 703          * with list_for_each_entry, so we assume no race condition
 704          * with regard to rndis_opts->bound access
 705          */
 706         if (!rndis_opts->bound) {
 707                 gether_set_gadget(rndis_opts->net, cdev->gadget);
 708                 status = gether_register_netdev(rndis_opts->net);
 709                 if (status)
 710                         goto fail;
 711                 rndis_opts->bound = true;
 712         }
 713
 714         us = usb_gstrings_attach(cdev, rndis_strings,
 715                                  ARRAY_SIZE(rndis_string_defs));
 716         if (IS_ERR(us)) {
 717                 status = PTR_ERR(us);
 718                 goto fail;
 719         }
 720         rndis_control_intf.iInterface = us[0].id;
 721         rndis_data_intf.iInterface = us[1].id;
 722         rndis_iad_descriptor.iFunction = us[2].id;
 723
 724         /* allocate instance-specific interface IDs */
 725         status = usb_interface_id(c, f);
 726         if (status < 0)
 727                 goto fail;
 728         rndis->ctrl_id = status;
 729         rndis_iad_descriptor.bFirstInterface = status;
 730
 731         rndis_control_intf.bInterfaceNumber = status;
 732         rndis_union_desc.bMasterInterface0 = status;
 733
 734         if (cdev->use_os_string)
 735                 f->os_desc_table[0].if_id =
 736                         rndis_iad_descriptor.bFirstInterface;
 737
 738         status = usb_interface_id(c, f);
 739         if (status < 0)
 740                 goto fail;
 741         rndis->data_id = status;
 742
 743         rndis_data_intf.bInterfaceNumber = status;
 744         rndis_union_desc.bSlaveInterface0 = status;
 745
 746         status = -ENODEV;
 747
 748         /* allocate instance-specific endpoints */
 749         ep = usb_ep_autoconfig(cdev->gadget, &fs_in_desc);
 750         if (!ep)
 751                 goto fail;
 752         rndis->port.in_ep = ep;
 753
 754         ep = usb_ep_autoconfig(cdev->gadget, &fs_out_desc);
 755         if (!ep)
 756                 goto fail;
 757         rndis->port.out_ep = ep;
 758
 759         /* NOTE:  a status/notification endpoint is, strictly speaking,
 760          * optional.  We don't treat it that way though!  It's simpler,
 761          * and some newer profiles don't treat it as optional.
 762          */
 763         ep = usb_ep_autoconfig(cdev->gadget, &fs_notify_desc);
 764         if (!ep)
 765                 goto fail;
 766         rndis->notify = ep;
 767
 768         status = -ENOMEM;
 769
 770         /* allocate notification request and buffer */
 771         rndis->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL);
 772         if (!rndis->notify_req)
 773                 goto fail;
 774         rndis->notify_req->buf = kmalloc(STATUS_BYTECOUNT, GFP_KERNEL);
 775         if (!rndis->notify_req->buf)
 776                 goto fail;
 777         rndis->notify_req->length = STATUS_BYTECOUNT;
 778         rndis->notify_req->context = rndis;
 779         rndis->notify_req->complete = rndis_response_complete;
 780
 781         /* support all relevant hardware speeds... we expect that when
 782          * hardware is dual speed, all bulk-capable endpoints work at
 783          * both speeds
 784          */
 785         hs_in_desc.bEndpointAddress = fs_in_desc.bEndpointAddress;
 786         hs_out_desc.bEndpointAddress = fs_out_desc.bEndpointAddress;
 787         hs_notify_desc.bEndpointAddress = fs_notify_desc.bEndpointAddress;
 788
 789         ss_in_desc.bEndpointAddress = fs_in_desc.bEndpointAddress;
 790         ss_out_desc.bEndpointAddress = fs_out_desc.bEndpointAddress;
 791         ss_notify_desc.bEndpointAddress = fs_notify_desc.bEndpointAddress;
 792
 793         status = usb_assign_descriptors(f, eth_fs_function, eth_hs_function,
 794                         eth_ss_function, NULL);
 795         if (status)
 796                 goto fail;
 797
 798         rndis->port.open = rndis_open;
 799         rndis->port.close = rndis_close;
 800
 801         rndis_set_param_medium(rndis->params, RNDIS_MEDIUM_802_3, 0);
 802         rndis_set_host_mac(rndis->params, rndis->ethaddr);
 803
 804         if (rndis->manufacturer && rndis->vendorID &&
 805                         rndis_set_param_vendor(rndis->params, rndis->vendorID,
 806                                                rndis->manufacturer)) {
 807                 status = -EINVAL;
 808                 goto fail_free_descs;
 809         }
 810
 811         /* NOTE:  all that is done without knowing or caring about
 812          * the network link ... which is unavailable to this code
 813          * until we're activated via set_alt().
 814          */
 815
 816         DBG(cdev, "RNDIS: %s speed IN/%s OUT/%s NOTIFY/%s\n",
 817                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 818                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 819                         rndis->port.in_ep->name, rndis->port.out_ep->name,
 820                         rndis->notify->name);
 821         return 0;
 822
 823 fail_free_descs:
 824         usb_free_all_descriptors(f);
 825 fail:
 826         kfree(f->os_desc_table);
 827         f->os_desc_n = 0;
 828
 829         if (rndis->notify_req) {
 830                 kfree(rndis->notify_req->buf);
 831                 usb_ep_free_request(rndis->notify, rndis->notify_req);
 832         }
 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 /* f_rndis_opts_class */
 875 USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(rndis, class);
 876
 877 /* f_rndis_opts_subclass */
 878 USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(rndis, subclass);
 879
 880 /* f_rndis_opts_protocol */
 881 USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(rndis, protocol);
 882
 883 static struct configfs_attribute *rndis_attrs[] = {
 884         &rndis_opts_attr_dev_addr,
 885         &rndis_opts_attr_host_addr,
 886         &rndis_opts_attr_qmult,
 887         &rndis_opts_attr_ifname,
 888         &rndis_opts_attr_class,
 889         &rndis_opts_attr_subclass,
 890         &rndis_opts_attr_protocol,
 891         NULL,
 892 };
 893
 894 static struct config_item_type rndis_func_type = {
 895         .ct_item_ops    = &rndis_item_ops,
 896         .ct_attrs       = rndis_attrs,
 897         .ct_owner       = THIS_MODULE,
 898 };
 899
 900 static void rndis_free_inst(struct usb_function_instance *f)
 901 {
 902         struct f_rndis_opts *opts;
 903
 904         opts = container_of(f, struct f_rndis_opts, func_inst);
 905         if (!opts->borrowed_net) {
 906                 if (opts->bound)
 907                         gether_cleanup(netdev_priv(opts->net));
 908                 else
 909                         free_netdev(opts->net);
 910         }
 911
 912         kfree(opts->rndis_interf_group);        /* single VLA chunk */
 913         kfree(opts);
 914 }
 915
 916 static struct usb_function_instance *rndis_alloc_inst(void)
 917 {
 918         struct f_rndis_opts *opts;
 919         struct usb_os_desc *descs[1];
 920         char *names[1];
 921         struct config_group *rndis_interf_group;
 922
 923         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 924         if (!opts)
 925                 return ERR_PTR(-ENOMEM);
 926         opts->rndis_os_desc.ext_compat_id = opts->rndis_ext_compat_id;
 927
 928         mutex_init(&opts->lock);
 929         opts->func_inst.free_func_inst = rndis_free_inst;
 930         opts->net = gether_setup_default();
 931         if (IS_ERR(opts->net)) {
 932                 struct net_device *net = opts->net;
 933                 kfree(opts);
 934                 return ERR_CAST(net);
 935         }
 936         INIT_LIST_HEAD(&opts->rndis_os_desc.ext_prop);
 937
 938         opts->class = rndis_iad_descriptor.bFunctionClass;
 939         opts->subclass = rndis_iad_descriptor.bFunctionSubClass;
 940         opts->protocol = rndis_iad_descriptor.bFunctionProtocol;
 941
 942         descs[0] = &opts->rndis_os_desc;
 943         names[0] = "rndis";
 944         config_group_init_type_name(&opts->func_inst.group, "",
 945                                     &rndis_func_type);
 946         rndis_interf_group =
 947                 usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs,
 948                                                names, THIS_MODULE);
 949         if (IS_ERR(rndis_interf_group)) {
 950                 rndis_free_inst(&opts->func_inst);
 951                 return ERR_CAST(rndis_interf_group);
 952         }
 953         opts->rndis_interf_group = rndis_interf_group;
 954
 955         return &opts->func_inst;
 956 }
 957
 958 static void rndis_free(struct usb_function *f)
 959 {
 960         struct f_rndis *rndis;
 961         struct f_rndis_opts *opts;
 962
 963         rndis = func_to_rndis(f);
 964         rndis_deregister(rndis->params);
 965         opts = container_of(f->fi, struct f_rndis_opts, func_inst);
 966         kfree(rndis);
 967         mutex_lock(&opts->lock);
 968         opts->refcnt--;
 969         mutex_unlock(&opts->lock);
 970 }
 971
 972 static void rndis_unbind(struct usb_configuration *c, struct usb_function *f)
 973 {
 974         struct f_rndis          *rndis = func_to_rndis(f);
 975
 976         kfree(f->os_desc_table);
 977         f->os_desc_n = 0;
 978         usb_free_all_descriptors(f);
 979
 980         kfree(rndis->notify_req->buf);
 981         usb_ep_free_request(rndis->notify, rndis->notify_req);
 982 }
 983
 984 static struct usb_function *rndis_alloc(struct usb_function_instance *fi)
 985 {
 986         struct f_rndis  *rndis;
 987         struct f_rndis_opts *opts;
 988         struct rndis_params *params;
 989
 990         /* allocate and initialize one new instance */
 991         rndis = kzalloc(sizeof(*rndis), GFP_KERNEL);
 992         if (!rndis)
 993                 return ERR_PTR(-ENOMEM);
 994
 995         opts = container_of(fi, struct f_rndis_opts, func_inst);
 996         mutex_lock(&opts->lock);
 997         opts->refcnt++;
 998
 999         gether_get_host_addr_u8(opts->net, rndis->ethaddr);
1000         rndis->vendorID = opts->vendor_id;
1001         rndis->manufacturer = opts->manufacturer;
1002
1003         rndis->port.ioport = netdev_priv(opts->net);
1004         mutex_unlock(&opts->lock);
1005         /* RNDIS activates when the host changes this filter */
1006         rndis->port.cdc_filter = 0;
1007
1008         /* RNDIS has special (and complex) framing */
1009         rndis->port.header_len = sizeof(struct rndis_packet_msg_type);
1010         rndis->port.wrap = rndis_add_header;
1011         rndis->port.unwrap = rndis_rm_hdr;
1012
1013         rndis->port.func.name = "rndis";
1014         /* descriptors are per-instance copies */
1015         rndis->port.func.bind = rndis_bind;
1016         rndis->port.func.unbind = rndis_unbind;
1017         rndis->port.func.set_alt = rndis_set_alt;
1018         rndis->port.func.setup = rndis_setup;
1019         rndis->port.func.disable = rndis_disable;
1020         rndis->port.func.free_func = rndis_free;
1021
1022         params = rndis_register(rndis_response_available, rndis);
1023         if (IS_ERR(params)) {
1024                 kfree(rndis);
1025                 return ERR_CAST(params);
1026         }
1027         rndis->params = params;
1028
1029         return &rndis->port.func;
1030 }
1031
1032 DECLARE_USB_FUNCTION_INIT(rndis, rndis_alloc_inst, rndis_alloc);
1033 MODULE_LICENSE("GPL");
1034 MODULE_AUTHOR("David Brownell");