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
  12 /* #define VERBOSE_DEBUG */
  13
  14 #include <linux/slab.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/device.h>
  18 #include <linux/etherdevice.h>
  19
  20 #include <linux/atomic.h>
  21
  22 #include "u_ether.h"
  23 #include "u_ether_configfs.h"
  24 #include "u_rndis.h"
  25 #include "rndis.h"
  26 #include "configfs.h"
  27
  28 /*
  29  * This function is an RNDIS Ethernet port -- a Microsoft protocol that's
  30  * been promoted instead of the standard CDC Ethernet.  The published RNDIS
  31  * spec is ambiguous, incomplete, and needlessly complex.  Variants such as
  32  * ActiveSync have even worse status in terms of specification.
  33  *
  34  * In short:  it's a protocol controlled by (and for) Microsoft, not for an
  35  * Open ecosystem or markets.  Linux supports it *only* because Microsoft
  36  * doesn't support the CDC Ethernet standard.
  37  *
  38  * The RNDIS data transfer model is complex, with multiple Ethernet packets
  39  * per USB message, and out of band data.  The control model is built around
  40  * what's essentially an "RNDIS RPC" protocol.  It's all wrapped in a CDC ACM
  41  * (modem, not Ethernet) veneer, with those ACM descriptors being entirely
  42  * useless (they're ignored).  RNDIS expects to be the only function in its
  43  * configuration, so it's no real help if you need composite devices; and
  44  * it expects to be the first configuration too.
  45  *
  46  * There is a single technical advantage of RNDIS over CDC Ethernet, if you
  47  * discount the fluff that its RPC can be made to deliver: it doesn't need
  48  * a NOP altsetting for the data interface.  That lets it work on some of the
  49  * "so smart it's stupid" hardware which takes over configuration changes
  50  * from the software, and adds restrictions like "no altsettings".
  51  *
  52  * Unfortunately MSFT's RNDIS drivers are buggy.  They hang or oops, and
  53  * have all sorts of contrary-to-specification oddities that can prevent
  54  * them from working sanely.  Since bugfixes (or accurate specs, letting
  55  * Linux work around those bugs) are unlikely to ever come from MSFT, you
  56  * may want to avoid using RNDIS on purely operational grounds.
  57  *
  58  * Omissions from the RNDIS 1.0 specification include:
  59  *
  60  *   - Power management ... references data that's scattered around lots
  61  *     of other documentation, which is incorrect/incomplete there too.
  62  *
  63  *   - There are various undocumented protocol requirements, like the need
  64  *     to send garbage in some control-OUT messages.
  65  *
  66  *   - MS-Windows drivers sometimes emit undocumented requests.
  67  */
  68
  69 struct f_rndis {
  70         struct gether                   port;
  71         u8                              ctrl_id, data_id;
  72         u8                              ethaddr[ETH_ALEN];
  73         u32                             vendorID;
  74         const char                      *manufacturer;
  75         struct rndis_params             *params;
  76
  77         struct usb_ep                   *notify;
  78         struct usb_request              *notify_req;
  79         atomic_t                        notify_count;
  80 };
  81
  82 static inline struct f_rndis *func_to_rndis(struct usb_function *f)
  83 {
  84         return container_of(f, struct f_rndis, port.func);
  85 }
  86
  87 /* peak (theoretical) bulk transfer rate in bits-per-second */
  88 static unsigned int bitrate(struct usb_gadget *g)
  89 {
  90         if (gadget_is_superspeed(g) && g->speed == USB_SPEED_SUPER)
  91                 return 13 * 1024 * 8 * 1000 * 8;
  92         else if (gadget_is_dualspeed(g) && g->speed == USB_SPEED_HIGH)
  93                 return 13 * 512 * 8 * 1000 * 8;
  94         else
  95                 return 19 * 64 * 1 * 1000 * 8;
  96 }
  97
  98 /*-------------------------------------------------------------------------*/
  99
 100 /*
 101  */
 102
 103 #define RNDIS_STATUS_INTERVAL_MS        32
 104 #define STATUS_BYTECOUNT                8       /* 8 bytes data */
 105
 106
 107 /* interface descriptor: */
 108
 109 static struct usb_interface_descriptor rndis_control_intf = {
 110         .bLength =              sizeof rndis_control_intf,
 111         .bDescriptorType =      USB_DT_INTERFACE,
 112
 113         /* .bInterfaceNumber = DYNAMIC */
 114         /* status endpoint is optional; this could be patched later */
 115         .bNumEndpoints =        1,
 116         .bInterfaceClass =      USB_CLASS_COMM,
 117         .bInterfaceSubClass =   USB_CDC_SUBCLASS_ACM,
 118         .bInterfaceProtocol =   USB_CDC_ACM_PROTO_VENDOR,
 119         /* .iInterface = DYNAMIC */
 120 };
 121
 122 static struct usb_cdc_header_desc header_desc = {
 123         .bLength =              sizeof header_desc,
 124         .bDescriptorType =      USB_DT_CS_INTERFACE,
 125         .bDescriptorSubType =   USB_CDC_HEADER_TYPE,
 126
 127         .bcdCDC =               cpu_to_le16(0x0110),
 128 };
 129
 130 static struct usb_cdc_call_mgmt_descriptor call_mgmt_descriptor = {
 131         .bLength =              sizeof call_mgmt_descriptor,
 132         .bDescriptorType =      USB_DT_CS_INTERFACE,
 133         .bDescriptorSubType =   USB_CDC_CALL_MANAGEMENT_TYPE,
 134
 135         .bmCapabilities =       0x00,
 136         .bDataInterface =       0x01,
 137 };
 138
 139 static struct usb_cdc_acm_descriptor rndis_acm_descriptor = {
 140         .bLength =              sizeof rndis_acm_descriptor,
 141         .bDescriptorType =      USB_DT_CS_INTERFACE,
 142         .bDescriptorSubType =   USB_CDC_ACM_TYPE,
 143
 144         .bmCapabilities =       0x00,
 145 };
 146
 147 static struct usb_cdc_union_desc rndis_union_desc = {
 148         .bLength =              sizeof(rndis_union_desc),
 149         .bDescriptorType =      USB_DT_CS_INTERFACE,
 150         .bDescriptorSubType =   USB_CDC_UNION_TYPE,
 151         /* .bMasterInterface0 = DYNAMIC */
 152         /* .bSlaveInterface0 =  DYNAMIC */
 153 };
 154
 155 /* the data interface has two bulk endpoints */
 156
 157 static struct usb_interface_descriptor rndis_data_intf = {
 158         .bLength =              sizeof rndis_data_intf,
 159         .bDescriptorType =      USB_DT_INTERFACE,
 160
 161         /* .bInterfaceNumber = DYNAMIC */
 162         .bNumEndpoints =        2,
 163         .bInterfaceClass =      USB_CLASS_CDC_DATA,
 164         .bInterfaceSubClass =   0,
 165         .bInterfaceProtocol =   0,
 166         /* .iInterface = DYNAMIC */
 167 };
 168
 169
 170 static struct usb_interface_assoc_descriptor
 171 rndis_iad_descriptor = {
 172         .bLength =              sizeof rndis_iad_descriptor,
 173         .bDescriptorType =      USB_DT_INTERFACE_ASSOCIATION,
 174
 175         .bFirstInterface =      0, /* XXX, hardcoded */
 176         .bInterfaceCount =      2,      // control + data
 177         .bFunctionClass =       USB_CLASS_COMM,
 178         .bFunctionSubClass =    USB_CDC_SUBCLASS_ETHERNET,
 179         .bFunctionProtocol =    USB_CDC_PROTO_NONE,
 180         /* .iFunction = DYNAMIC */
 181 };
 182
 183 /* full speed support: */
 184
 185 static struct usb_endpoint_descriptor fs_notify_desc = {
 186         .bLength =              USB_DT_ENDPOINT_SIZE,
 187         .bDescriptorType =      USB_DT_ENDPOINT,
 188
 189         .bEndpointAddress =     USB_DIR_IN,
 190         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 191         .wMaxPacketSize =       cpu_to_le16(STATUS_BYTECOUNT),
 192         .bInterval =            RNDIS_STATUS_INTERVAL_MS,
 193 };
 194
 195 static struct usb_endpoint_descriptor fs_in_desc = {
 196         .bLength =              USB_DT_ENDPOINT_SIZE,
 197         .bDescriptorType =      USB_DT_ENDPOINT,
 198
 199         .bEndpointAddress =     USB_DIR_IN,
 200         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 201 };
 202
 203 static struct usb_endpoint_descriptor fs_out_desc = {
 204         .bLength =              USB_DT_ENDPOINT_SIZE,
 205         .bDescriptorType =      USB_DT_ENDPOINT,
 206
 207         .bEndpointAddress =     USB_DIR_OUT,
 208         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 209 };
 210
 211 static struct usb_descriptor_header *eth_fs_function[] = {
 212         (struct usb_descriptor_header *) &rndis_iad_descriptor,
 213
 214         /* control interface matches ACM, not Ethernet */
 215         (struct usb_descriptor_header *) &rndis_control_intf,
 216         (struct usb_descriptor_header *) &header_desc,
 217         (struct usb_descriptor_header *) &call_mgmt_descriptor,
 218         (struct usb_descriptor_header *) &rndis_acm_descriptor,
 219         (struct usb_descriptor_header *) &rndis_union_desc,
 220         (struct usb_descriptor_header *) &fs_notify_desc,
 221
 222         /* data interface has no altsetting */
 223         (struct usb_descriptor_header *) &rndis_data_intf,
 224         (struct usb_descriptor_header *) &fs_in_desc,
 225         (struct usb_descriptor_header *) &fs_out_desc,
 226         NULL,
 227 };
 228
 229 /* high speed support: */
 230
 231 static struct usb_endpoint_descriptor hs_notify_desc = {
 232         .bLength =              USB_DT_ENDPOINT_SIZE,
 233         .bDescriptorType =      USB_DT_ENDPOINT,
 234
 235         .bEndpointAddress =     USB_DIR_IN,
 236         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 237         .wMaxPacketSize =       cpu_to_le16(STATUS_BYTECOUNT),
 238         .bInterval =            USB_MS_TO_HS_INTERVAL(RNDIS_STATUS_INTERVAL_MS)
 239 };
 240
 241 static struct usb_endpoint_descriptor hs_in_desc = {
 242         .bLength =              USB_DT_ENDPOINT_SIZE,
 243         .bDescriptorType =      USB_DT_ENDPOINT,
 244
 245         .bEndpointAddress =     USB_DIR_IN,
 246         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 247         .wMaxPacketSize =       cpu_to_le16(512),
 248 };
 249
 250 static struct usb_endpoint_descriptor hs_out_desc = {
 251         .bLength =              USB_DT_ENDPOINT_SIZE,
 252         .bDescriptorType =      USB_DT_ENDPOINT,
 253
 254         .bEndpointAddress =     USB_DIR_OUT,
 255         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 256         .wMaxPacketSize =       cpu_to_le16(512),
 257 };
 258
 259 static struct usb_descriptor_header *eth_hs_function[] = {
 260         (struct usb_descriptor_header *) &rndis_iad_descriptor,
 261
 262         /* control interface matches ACM, not Ethernet */
 263         (struct usb_descriptor_header *) &rndis_control_intf,
 264         (struct usb_descriptor_header *) &header_desc,
 265         (struct usb_descriptor_header *) &call_mgmt_descriptor,
 266         (struct usb_descriptor_header *) &rndis_acm_descriptor,
 267         (struct usb_descriptor_header *) &rndis_union_desc,
 268         (struct usb_descriptor_header *) &hs_notify_desc,
 269
 270         /* data interface has no altsetting */
 271         (struct usb_descriptor_header *) &rndis_data_intf,
 272         (struct usb_descriptor_header *) &hs_in_desc,
 273         (struct usb_descriptor_header *) &hs_out_desc,
 274         NULL,
 275 };
 276
 277 /* super speed support: */
 278
 279 static struct usb_endpoint_descriptor ss_notify_desc = {
 280         .bLength =              USB_DT_ENDPOINT_SIZE,
 281         .bDescriptorType =      USB_DT_ENDPOINT,
 282
 283         .bEndpointAddress =     USB_DIR_IN,
 284         .bmAttributes =         USB_ENDPOINT_XFER_INT,
 285         .wMaxPacketSize =       cpu_to_le16(STATUS_BYTECOUNT),
 286         .bInterval =            USB_MS_TO_HS_INTERVAL(RNDIS_STATUS_INTERVAL_MS)
 287 };
 288
 289 static struct usb_ss_ep_comp_descriptor ss_intr_comp_desc = {
 290         .bLength =              sizeof ss_intr_comp_desc,
 291         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 292
 293         /* the following 3 values can be tweaked if necessary */
 294         /* .bMaxBurst =         0, */
 295         /* .bmAttributes =      0, */
 296         .wBytesPerInterval =    cpu_to_le16(STATUS_BYTECOUNT),
 297 };
 298
 299 static struct usb_endpoint_descriptor ss_in_desc = {
 300         .bLength =              USB_DT_ENDPOINT_SIZE,
 301         .bDescriptorType =      USB_DT_ENDPOINT,
 302
 303         .bEndpointAddress =     USB_DIR_IN,
 304         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 305         .wMaxPacketSize =       cpu_to_le16(1024),
 306 };
 307
 308 static struct usb_endpoint_descriptor ss_out_desc = {
 309         .bLength =              USB_DT_ENDPOINT_SIZE,
 310         .bDescriptorType =      USB_DT_ENDPOINT,
 311
 312         .bEndpointAddress =     USB_DIR_OUT,
 313         .bmAttributes =         USB_ENDPOINT_XFER_BULK,
 314         .wMaxPacketSize =       cpu_to_le16(1024),
 315 };
 316
 317 static struct usb_ss_ep_comp_descriptor ss_bulk_comp_desc = {
 318         .bLength =              sizeof ss_bulk_comp_desc,
 319         .bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 320
 321         /* the following 2 values can be tweaked if necessary */
 322         /* .bMaxBurst =         0, */
 323         /* .bmAttributes =      0, */
 324 };
 325
 326 static struct usb_descriptor_header *eth_ss_function[] = {
 327         (struct usb_descriptor_header *) &rndis_iad_descriptor,
 328
 329         /* control interface matches ACM, not Ethernet */
 330         (struct usb_descriptor_header *) &rndis_control_intf,
 331         (struct usb_descriptor_header *) &header_desc,
 332         (struct usb_descriptor_header *) &call_mgmt_descriptor,
 333         (struct usb_descriptor_header *) &rndis_acm_descriptor,
 334         (struct usb_descriptor_header *) &rndis_union_desc,
 335         (struct usb_descriptor_header *) &ss_notify_desc,
 336         (struct usb_descriptor_header *) &ss_intr_comp_desc,
 337
 338         /* data interface has no altsetting */
 339         (struct usb_descriptor_header *) &rndis_data_intf,
 340         (struct usb_descriptor_header *) &ss_in_desc,
 341         (struct usb_descriptor_header *) &ss_bulk_comp_desc,
 342         (struct usb_descriptor_header *) &ss_out_desc,
 343         (struct usb_descriptor_header *) &ss_bulk_comp_desc,
 344         NULL,
 345 };
 346
 347 /* string descriptors: */
 348
 349 static struct usb_string rndis_string_defs[] = {
 350         [0].s = "RNDIS Communications Control",
 351         [1].s = "RNDIS Ethernet Data",
 352         [2].s = "RNDIS",
 353         {  } /* end of list */
 354 };
 355
 356 static struct usb_gadget_strings rndis_string_table = {
 357         .language =             0x0409, /* en-us */
 358         .strings =              rndis_string_defs,
 359 };
 360
 361 static struct usb_gadget_strings *rndis_strings[] = {
 362         &rndis_string_table,
 363         NULL,
 364 };
 365
 366 /*-------------------------------------------------------------------------*/
 367
 368 static struct sk_buff *rndis_add_header(struct gether *port,
 369                                         struct sk_buff *skb)
 370 {
 371         struct sk_buff *skb2;
 372
 373         if (!skb)
 374                 return NULL;
 375
 376         skb2 = skb_realloc_headroom(skb, sizeof(struct rndis_packet_msg_type));
 377         rndis_add_hdr(skb2);
 378
 379         dev_kfree_skb(skb);
 380         return skb2;
 381 }
 382
 383 static void rndis_response_available(void *_rndis)
 384 {
 385         struct f_rndis                  *rndis = _rndis;
 386         struct usb_request              *req = rndis->notify_req;
 387         struct usb_composite_dev        *cdev = rndis->port.func.config->cdev;
 388         __le32                          *data = req->buf;
 389         int                             status;
 390
 391         if (atomic_inc_return(&rndis->notify_count) != 1)
 392                 return;
 393
 394         /* Send RNDIS RESPONSE_AVAILABLE notification; a
 395          * USB_CDC_NOTIFY_RESPONSE_AVAILABLE "should" work too
 396          *
 397          * This is the only notification defined by RNDIS.
 398          */
 399         data[0] = cpu_to_le32(1);
 400         data[1] = cpu_to_le32(0);
 401
 402         status = usb_ep_queue(rndis->notify, req, GFP_ATOMIC);
 403         if (status) {
 404                 atomic_dec(&rndis->notify_count);
 405                 DBG(cdev, "notify/0 --> %d\n", status);
 406         }
 407 }
 408
 409 static void rndis_response_complete(struct usb_ep *ep, struct usb_request *req)
 410 {
 411         struct f_rndis                  *rndis = req->context;
 412         struct usb_composite_dev        *cdev = rndis->port.func.config->cdev;
 413         int                             status = req->status;
 414
 415         /* after TX:
 416          *  - USB_CDC_GET_ENCAPSULATED_RESPONSE (ep0/control)
 417          *  - RNDIS_RESPONSE_AVAILABLE (status/irq)
 418          */
 419         switch (status) {
 420         case -ECONNRESET:
 421         case -ESHUTDOWN:
 422                 /* connection gone */
 423                 atomic_set(&rndis->notify_count, 0);
 424                 break;
 425         default:
 426                 DBG(cdev, "RNDIS %s response error %d, %d/%d\n",
 427                         ep->name, status,
 428                         req->actual, req->length);
 429                 /* FALLTHROUGH */
 430         case 0:
 431                 if (ep != rndis->notify)
 432                         break;
 433
 434                 /* handle multiple pending RNDIS_RESPONSE_AVAILABLE
 435                  * notifications by resending until we're done
 436                  */
 437                 if (atomic_dec_and_test(&rndis->notify_count))
 438                         break;
 439                 status = usb_ep_queue(rndis->notify, req, GFP_ATOMIC);
 440                 if (status) {
 441                         atomic_dec(&rndis->notify_count);
 442                         DBG(cdev, "notify/1 --> %d\n", status);
 443                 }
 444                 break;
 445         }
 446 }
 447
 448 static void rndis_command_complete(struct usb_ep *ep, struct usb_request *req)
 449 {
 450         struct f_rndis                  *rndis = req->context;
 451         int                             status;
 452
 453         /* received RNDIS command from USB_CDC_SEND_ENCAPSULATED_COMMAND */
 454 //      spin_lock(&dev->lock);
 455         status = rndis_msg_parser(rndis->params, (u8 *) req->buf);
 456         if (status < 0)
 457                 pr_err("RNDIS command error %d, %d/%d\n",
 458                         status, req->actual, req->length);
 459 //      spin_unlock(&dev->lock);
 460 }
 461
 462 static int
 463 rndis_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
 464 {
 465         struct f_rndis          *rndis = func_to_rndis(f);
 466         struct usb_composite_dev *cdev = f->config->cdev;
 467         struct usb_request      *req = cdev->req;
 468         int                     value = -EOPNOTSUPP;
 469         u16                     w_index = le16_to_cpu(ctrl->wIndex);
 470         u16                     w_value = le16_to_cpu(ctrl->wValue);
 471         u16                     w_length = le16_to_cpu(ctrl->wLength);
 472
 473         /* composite driver infrastructure handles everything except
 474          * CDC class messages; interface activation uses set_alt().
 475          */
 476         switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
 477
 478         /* RNDIS uses the CDC command encapsulation mechanism to implement
 479          * an RPC scheme, with much getting/setting of attributes by OID.
 480          */
 481         case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 482                         | USB_CDC_SEND_ENCAPSULATED_COMMAND:
 483                 if (w_value || w_index != rndis->ctrl_id)
 484                         goto invalid;
 485                 /* read the request; process it later */
 486                 value = w_length;
 487                 req->complete = rndis_command_complete;
 488                 req->context = rndis;
 489                 /* later, rndis_response_available() sends a notification */
 490                 break;
 491
 492         case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8)
 493                         | USB_CDC_GET_ENCAPSULATED_RESPONSE:
 494                 if (w_value || w_index != rndis->ctrl_id)
 495                         goto invalid;
 496                 else {
 497                         u8 *buf;
 498                         u32 n;
 499
 500                         /* return the result */
 501                         buf = rndis_get_next_response(rndis->params, &n);
 502                         if (buf) {
 503                                 memcpy(req->buf, buf, n);
 504                                 req->complete = rndis_response_complete;
 505                                 req->context = rndis;
 506                                 rndis_free_response(rndis->params, buf);
 507                                 value = n;
 508                         }
 509                         /* else stalls ... spec says to avoid that */
 510                 }
 511                 break;
 512
 513         default:
 514 invalid:
 515                 VDBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
 516                         ctrl->bRequestType, ctrl->bRequest,
 517                         w_value, w_index, w_length);
 518         }
 519
 520         /* respond with data transfer or status phase? */
 521         if (value >= 0) {
 522                 DBG(cdev, "rndis req%02x.%02x v%04x i%04x l%d\n",
 523                         ctrl->bRequestType, ctrl->bRequest,
 524                         w_value, w_index, w_length);
 525                 req->zero = (value < w_length);
 526                 req->length = value;
 527                 value = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
 528                 if (value < 0)
 529                         ERROR(cdev, "rndis response on err %d\n", value);
 530         }
 531
 532         /* device either stalls (value < 0) or reports success */
 533         return value;
 534 }
 535
 536
 537 static int rndis_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 538 {
 539         struct f_rndis          *rndis = func_to_rndis(f);
 540         struct usb_composite_dev *cdev = f->config->cdev;
 541
 542         /* we know alt == 0 */
 543
 544         if (intf == rndis->ctrl_id) {
 545                 VDBG(cdev, "reset rndis control %d\n", intf);
 546                 usb_ep_disable(rndis->notify);
 547
 548                 if (!rndis->notify->desc) {
 549                         VDBG(cdev, "init rndis ctrl %d\n", intf);
 550                         if (config_ep_by_speed(cdev->gadget, f, rndis->notify))
 551                                 goto fail;
 552                 }
 553                 usb_ep_enable(rndis->notify);
 554
 555         } else if (intf == rndis->data_id) {
 556                 struct net_device       *net;
 557
 558                 if (rndis->port.in_ep->enabled) {
 559                         DBG(cdev, "reset rndis\n");
 560                         gether_disconnect(&rndis->port);
 561                 }
 562
 563                 if (!rndis->port.in_ep->desc || !rndis->port.out_ep->desc) {
 564                         DBG(cdev, "init rndis\n");
 565                         if (config_ep_by_speed(cdev->gadget, f,
 566                                                rndis->port.in_ep) ||
 567                             config_ep_by_speed(cdev->gadget, f,
 568                                                rndis->port.out_ep)) {
 569                                 rndis->port.in_ep->desc = NULL;
 570                                 rndis->port.out_ep->desc = NULL;
 571                                 goto fail;
 572                         }
 573                 }
 574
 575                 /* Avoid ZLPs; they can be troublesome. */
 576                 rndis->port.is_zlp_ok = false;
 577
 578                 /* RNDIS should be in the "RNDIS uninitialized" state,
 579                  * either never activated or after rndis_uninit().
 580                  *
 581                  * We don't want data to flow here until a nonzero packet
 582                  * filter is set, at which point it enters "RNDIS data
 583                  * initialized" state ... but we do want the endpoints
 584                  * to be activated.  It's a strange little state.
 585                  *
 586                  * REVISIT the RNDIS gadget code has done this wrong for a
 587                  * very long time.  We need another call to the link layer
 588                  * code -- gether_updown(...bool) maybe -- to do it right.
 589                  */
 590                 rndis->port.cdc_filter = 0;
 591
 592                 DBG(cdev, "RNDIS RX/TX early activation ... \n");
 593                 net = gether_connect(&rndis->port);
 594                 if (IS_ERR(net))
 595                         return PTR_ERR(net);
 596
 597                 rndis_set_param_dev(rndis->params, net,
 598                                 &rndis->port.cdc_filter);
 599         } else
 600                 goto fail;
 601
 602         return 0;
 603 fail:
 604         return -EINVAL;
 605 }
 606
 607 static void rndis_disable(struct usb_function *f)
 608 {
 609         struct f_rndis          *rndis = func_to_rndis(f);
 610         struct usb_composite_dev *cdev = f->config->cdev;
 611
 612         if (!rndis->notify->enabled)
 613                 return;
 614
 615         DBG(cdev, "rndis deactivated\n");
 616
 617         rndis_uninit(rndis->params);
 618         gether_disconnect(&rndis->port);
 619
 620         usb_ep_disable(rndis->notify);
 621 }
 622
 623 /*-------------------------------------------------------------------------*/
 624
 625 /*
 626  * This isn't quite the same mechanism as CDC Ethernet, since the
 627  * notification scheme passes less data, but the same set of link
 628  * states must be tested.  A key difference is that altsettings are
 629  * not used to tell whether the link should send packets or not.
 630  */
 631
 632 static void rndis_open(struct gether *geth)
 633 {
 634         struct f_rndis          *rndis = func_to_rndis(&geth->func);
 635         struct usb_composite_dev *cdev = geth->func.config->cdev;
 636
 637         DBG(cdev, "%s\n", __func__);
 638
 639         rndis_set_param_medium(rndis->params, RNDIS_MEDIUM_802_3,
 640                                 bitrate(cdev->gadget) / 100);
 641         rndis_signal_connect(rndis->params);
 642 }
 643
 644 static void rndis_close(struct gether *geth)
 645 {
 646         struct f_rndis          *rndis = func_to_rndis(&geth->func);
 647
 648         DBG(geth->func.config->cdev, "%s\n", __func__);
 649
 650         rndis_set_param_medium(rndis->params, RNDIS_MEDIUM_802_3, 0);
 651         rndis_signal_disconnect(rndis->params);
 652 }
 653
 654 /*-------------------------------------------------------------------------*/
 655
 656 /* Some controllers can't support RNDIS ... */
 657 static inline bool can_support_rndis(struct usb_configuration *c)
 658 {
 659         /* everything else is *presumably* fine */
 660         return true;
 661 }
 662
 663 /* ethernet function driver setup/binding */
 664
 665 static int
 666 rndis_bind(struct usb_configuration *c, struct usb_function *f)
 667 {
 668         struct usb_composite_dev *cdev = c->cdev;
 669         struct f_rndis          *rndis = func_to_rndis(f);
 670         struct usb_string       *us;
 671         int                     status;
 672         struct usb_ep           *ep;
 673
 674         struct f_rndis_opts *rndis_opts;
 675
 676         if (!can_support_rndis(c))
 677                 return -EINVAL;
 678
 679         rndis_opts = container_of(f->fi, struct f_rndis_opts, func_inst);
 680
 681         if (cdev->use_os_string) {
 682                 f->os_desc_table = kzalloc(sizeof(*f->os_desc_table),
 683                                            GFP_KERNEL);
 684                 if (!f->os_desc_table)
 685                         return -ENOMEM;
 686                 f->os_desc_n = 1;
 687                 f->os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc;
 688         }
 689
 690         rndis_iad_descriptor.bFunctionClass = rndis_opts->class;
 691         rndis_iad_descriptor.bFunctionSubClass = rndis_opts->subclass;
 692         rndis_iad_descriptor.bFunctionProtocol = rndis_opts->protocol;
 693
 694         /*
 695          * in drivers/usb/gadget/configfs.c:configfs_composite_bind()
 696          * configurations are bound in sequence with list_for_each_entry,
 697          * in each configuration its functions are bound in sequence
 698          * with list_for_each_entry, so we assume no race condition
 699          * with regard to rndis_opts->bound access
 700          */
 701         if (!rndis_opts->bound) {
 702                 gether_set_gadget(rndis_opts->net, cdev->gadget);
 703                 status = gether_register_netdev(rndis_opts->net);
 704                 if (status)
 705                         goto fail;
 706                 rndis_opts->bound = true;
 707         }
 708
 709         us = usb_gstrings_attach(cdev, rndis_strings,
 710                                  ARRAY_SIZE(rndis_string_defs));
 711         if (IS_ERR(us)) {
 712                 status = PTR_ERR(us);
 713                 goto fail;
 714         }
 715         rndis_control_intf.iInterface = us[0].id;
 716         rndis_data_intf.iInterface = us[1].id;
 717         rndis_iad_descriptor.iFunction = us[2].id;
 718
 719         /* allocate instance-specific interface IDs */
 720         status = usb_interface_id(c, f);
 721         if (status < 0)
 722                 goto fail;
 723         rndis->ctrl_id = status;
 724         rndis_iad_descriptor.bFirstInterface = status;
 725
 726         rndis_control_intf.bInterfaceNumber = status;
 727         rndis_union_desc.bMasterInterface0 = status;
 728
 729         if (cdev->use_os_string)
 730                 f->os_desc_table[0].if_id =
 731                         rndis_iad_descriptor.bFirstInterface;
 732
 733         status = usb_interface_id(c, f);
 734         if (status < 0)
 735                 goto fail;
 736         rndis->data_id = status;
 737
 738         rndis_data_intf.bInterfaceNumber = status;
 739         rndis_union_desc.bSlaveInterface0 = status;
 740
 741         status = -ENODEV;
 742
 743         /* allocate instance-specific endpoints */
 744         ep = usb_ep_autoconfig(cdev->gadget, &fs_in_desc);
 745         if (!ep)
 746                 goto fail;
 747         rndis->port.in_ep = ep;
 748
 749         ep = usb_ep_autoconfig(cdev->gadget, &fs_out_desc);
 750         if (!ep)
 751                 goto fail;
 752         rndis->port.out_ep = ep;
 753
 754         /* NOTE:  a status/notification endpoint is, strictly speaking,
 755          * optional.  We don't treat it that way though!  It's simpler,
 756          * and some newer profiles don't treat it as optional.
 757          */
 758         ep = usb_ep_autoconfig(cdev->gadget, &fs_notify_desc);
 759         if (!ep)
 760                 goto fail;
 761         rndis->notify = ep;
 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, NULL);
 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->params, RNDIS_MEDIUM_802_3, 0);
 797         rndis_set_host_mac(rndis->params, rndis->ethaddr);
 798
 799         if (rndis->manufacturer && rndis->vendorID &&
 800                         rndis_set_param_vendor(rndis->params, rndis->vendorID,
 801                                                rndis->manufacturer)) {
 802                 status = -EINVAL;
 803                 goto fail_free_descs;
 804         }
 805
 806         /* NOTE:  all that is done without knowing or caring about
 807          * the network link ... which is unavailable to this code
 808          * until we're activated via set_alt().
 809          */
 810
 811         DBG(cdev, "RNDIS: %s speed IN/%s OUT/%s NOTIFY/%s\n",
 812                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 813                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 814                         rndis->port.in_ep->name, rndis->port.out_ep->name,
 815                         rndis->notify->name);
 816         return 0;
 817
 818 fail_free_descs:
 819         usb_free_all_descriptors(f);
 820 fail:
 821         kfree(f->os_desc_table);
 822         f->os_desc_n = 0;
 823
 824         if (rndis->notify_req) {
 825                 kfree(rndis->notify_req->buf);
 826                 usb_ep_free_request(rndis->notify, rndis->notify_req);
 827         }
 828
 829         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 830
 831         return status;
 832 }
 833
 834 void rndis_borrow_net(struct usb_function_instance *f, struct net_device *net)
 835 {
 836         struct f_rndis_opts *opts;
 837
 838         opts = container_of(f, struct f_rndis_opts, func_inst);
 839         if (opts->bound)
 840                 gether_cleanup(netdev_priv(opts->net));
 841         else
 842                 free_netdev(opts->net);
 843         opts->borrowed_net = opts->bound = true;
 844         opts->net = net;
 845 }
 846 EXPORT_SYMBOL_GPL(rndis_borrow_net);
 847
 848 static inline struct f_rndis_opts *to_f_rndis_opts(struct config_item *item)
 849 {
 850         return container_of(to_config_group(item), struct f_rndis_opts,
 851                             func_inst.group);
 852 }
 853
 854 /* f_rndis_item_ops */
 855 USB_ETHERNET_CONFIGFS_ITEM(rndis);
 856
 857 /* f_rndis_opts_dev_addr */
 858 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(rndis);
 859
 860 /* f_rndis_opts_host_addr */
 861 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(rndis);
 862
 863 /* f_rndis_opts_qmult */
 864 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(rndis);
 865
 866 /* f_rndis_opts_ifname */
 867 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(rndis);
 868
 869 /* f_rndis_opts_class */
 870 USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(rndis, class);
 871
 872 /* f_rndis_opts_subclass */
 873 USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(rndis, subclass);
 874
 875 /* f_rndis_opts_protocol */
 876 USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(rndis, protocol);
 877
 878 static struct configfs_attribute *rndis_attrs[] = {
 879         &rndis_opts_attr_dev_addr,
 880         &rndis_opts_attr_host_addr,
 881         &rndis_opts_attr_qmult,
 882         &rndis_opts_attr_ifname,
 883         &rndis_opts_attr_class,
 884         &rndis_opts_attr_subclass,
 885         &rndis_opts_attr_protocol,
 886         NULL,
 887 };
 888
 889 static struct config_item_type rndis_func_type = {
 890         .ct_item_ops    = &rndis_item_ops,
 891         .ct_attrs       = rndis_attrs,
 892         .ct_owner       = THIS_MODULE,
 893 };
 894
 895 static void rndis_free_inst(struct usb_function_instance *f)
 896 {
 897         struct f_rndis_opts *opts;
 898
 899         opts = container_of(f, struct f_rndis_opts, func_inst);
 900         if (!opts->borrowed_net) {
 901                 if (opts->bound)
 902                         gether_cleanup(netdev_priv(opts->net));
 903                 else
 904                         free_netdev(opts->net);
 905         }
 906
 907         kfree(opts->rndis_interf_group);        /* single VLA chunk */
 908         kfree(opts);
 909 }
 910
 911 static struct usb_function_instance *rndis_alloc_inst(void)
 912 {
 913         struct f_rndis_opts *opts;
 914         struct usb_os_desc *descs[1];
 915         char *names[1];
 916         struct config_group *rndis_interf_group;
 917
 918         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 919         if (!opts)
 920                 return ERR_PTR(-ENOMEM);
 921         opts->rndis_os_desc.ext_compat_id = opts->rndis_ext_compat_id;
 922
 923         mutex_init(&opts->lock);
 924         opts->func_inst.free_func_inst = rndis_free_inst;
 925         opts->net = gether_setup_default();
 926         if (IS_ERR(opts->net)) {
 927                 struct net_device *net = opts->net;
 928                 kfree(opts);
 929                 return ERR_CAST(net);
 930         }
 931         INIT_LIST_HEAD(&opts->rndis_os_desc.ext_prop);
 932
 933         opts->class = rndis_iad_descriptor.bFunctionClass;
 934         opts->subclass = rndis_iad_descriptor.bFunctionSubClass;
 935         opts->protocol = rndis_iad_descriptor.bFunctionProtocol;
 936
 937         descs[0] = &opts->rndis_os_desc;
 938         names[0] = "rndis";
 939         config_group_init_type_name(&opts->func_inst.group, "",
 940                                     &rndis_func_type);
 941         rndis_interf_group =
 942                 usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs,
 943                                                names, THIS_MODULE);
 944         if (IS_ERR(rndis_interf_group)) {
 945                 rndis_free_inst(&opts->func_inst);
 946                 return ERR_CAST(rndis_interf_group);
 947         }
 948         opts->rndis_interf_group = rndis_interf_group;
 949
 950         return &opts->func_inst;
 951 }
 952
 953 static void rndis_free(struct usb_function *f)
 954 {
 955         struct f_rndis *rndis;
 956         struct f_rndis_opts *opts;
 957
 958         rndis = func_to_rndis(f);
 959         rndis_deregister(rndis->params);
 960         opts = container_of(f->fi, struct f_rndis_opts, func_inst);
 961         kfree(rndis);
 962         mutex_lock(&opts->lock);
 963         opts->refcnt--;
 964         mutex_unlock(&opts->lock);
 965 }
 966
 967 static void rndis_unbind(struct usb_configuration *c, struct usb_function *f)
 968 {
 969         struct f_rndis          *rndis = func_to_rndis(f);
 970
 971         kfree(f->os_desc_table);
 972         f->os_desc_n = 0;
 973         usb_free_all_descriptors(f);
 974
 975         kfree(rndis->notify_req->buf);
 976         usb_ep_free_request(rndis->notify, rndis->notify_req);
 977 }
 978
 979 static struct usb_function *rndis_alloc(struct usb_function_instance *fi)
 980 {
 981         struct f_rndis  *rndis;
 982         struct f_rndis_opts *opts;
 983         struct rndis_params *params;
 984
 985         /* allocate and initialize one new instance */
 986         rndis = kzalloc(sizeof(*rndis), GFP_KERNEL);
 987         if (!rndis)
 988                 return ERR_PTR(-ENOMEM);
 989
 990         opts = container_of(fi, struct f_rndis_opts, func_inst);
 991         mutex_lock(&opts->lock);
 992         opts->refcnt++;
 993
 994         gether_get_host_addr_u8(opts->net, rndis->ethaddr);
 995         rndis->vendorID = opts->vendor_id;
 996         rndis->manufacturer = opts->manufacturer;
 997
 998         rndis->port.ioport = netdev_priv(opts->net);
 999         mutex_unlock(&opts->lock);
1000         /* RNDIS activates when the host changes this filter */
1001         rndis->port.cdc_filter = 0;
1002
1003         /* RNDIS has special (and complex) framing */
1004         rndis->port.header_len = sizeof(struct rndis_packet_msg_type);
1005         rndis->port.wrap = rndis_add_header;
1006         rndis->port.unwrap = rndis_rm_hdr;
1007
1008         rndis->port.func.name = "rndis";
1009         /* descriptors are per-instance copies */
1010         rndis->port.func.bind = rndis_bind;
1011         rndis->port.func.unbind = rndis_unbind;
1012         rndis->port.func.set_alt = rndis_set_alt;
1013         rndis->port.func.setup = rndis_setup;
1014         rndis->port.func.disable = rndis_disable;
1015         rndis->port.func.free_func = rndis_free;
1016
1017         params = rndis_register(rndis_response_available, rndis);
1018         if (IS_ERR(params)) {
1019                 kfree(rndis);
1020                 return ERR_CAST(params);
1021         }
1022         rndis->params = params;
1023
1024         return &rndis->port.func;
1025 }
1026
1027 DECLARE_USB_FUNCTION_INIT(rndis, rndis_alloc_inst, rndis_alloc);
1028 MODULE_LICENSE("GPL");
1029 MODULE_AUTHOR("David Brownell");