root/drivers/usb/gadget/function/f_rndis.c

DEFINITIONS

1. func_to_rndis
2. bitrate
3. rndis_add_header
4. rndis_response_available
5. rndis_response_complete
6. rndis_command_complete
7. rndis_setup
8. rndis_set_alt
9. rndis_disable
10. rndis_open
11. rndis_close
12. can_support_rndis
13. rndis_bind
14. rndis_borrow_net
15. to_f_rndis_opts
16. rndis_free_inst
17. rndis_alloc_inst
18. rndis_free
19. rndis_unbind
20. rndis_alloc

   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         rndis->notify->desc = NULL;
 622 }
 623 
 624 /*-------------------------------------------------------------------------*/
 625 
 626 /*
 627  * This isn't quite the same mechanism as CDC Ethernet, since the
 628  * notification scheme passes less data, but the same set of link
 629  * states must be tested.  A key difference is that altsettings are
 630  * not used to tell whether the link should send packets or not.
 631  */
 632 
 633 static void rndis_open(struct gether *geth)
 634 {
 635         struct f_rndis          *rndis = func_to_rndis(&geth->func);
 636         struct usb_composite_dev *cdev = geth->func.config->cdev;
 637 
 638         DBG(cdev, "%s\n", __func__);
 639 
 640         rndis_set_param_medium(rndis->params, RNDIS_MEDIUM_802_3,
 641                                 bitrate(cdev->gadget) / 100);
 642         rndis_signal_connect(rndis->params);
 643 }
 644 
 645 static void rndis_close(struct gether *geth)
 646 {
 647         struct f_rndis          *rndis = func_to_rndis(&geth->func);
 648 
 649         DBG(geth->func.config->cdev, "%s\n", __func__);
 650 
 651         rndis_set_param_medium(rndis->params, RNDIS_MEDIUM_802_3, 0);
 652         rndis_signal_disconnect(rndis->params);
 653 }
 654 
 655 /*-------------------------------------------------------------------------*/
 656 
 657 /* Some controllers can't support RNDIS ... */
 658 static inline bool can_support_rndis(struct usb_configuration *c)
 659 {
 660         /* everything else is *presumably* fine */
 661         return true;
 662 }
 663 
 664 /* ethernet function driver setup/binding */
 665 
 666 static int
 667 rndis_bind(struct usb_configuration *c, struct usb_function *f)
 668 {
 669         struct usb_composite_dev *cdev = c->cdev;
 670         struct f_rndis          *rndis = func_to_rndis(f);
 671         struct usb_string       *us;
 672         int                     status;
 673         struct usb_ep           *ep;
 674 
 675         struct f_rndis_opts *rndis_opts;
 676 
 677         if (!can_support_rndis(c))
 678                 return -EINVAL;
 679 
 680         rndis_opts = container_of(f->fi, struct f_rndis_opts, func_inst);
 681 
 682         if (cdev->use_os_string) {
 683                 f->os_desc_table = kzalloc(sizeof(*f->os_desc_table),
 684                                            GFP_KERNEL);
 685                 if (!f->os_desc_table)
 686                         return -ENOMEM;
 687                 f->os_desc_n = 1;
 688                 f->os_desc_table[0].os_desc = &rndis_opts->rndis_os_desc;
 689         }
 690 
 691         rndis_iad_descriptor.bFunctionClass = rndis_opts->class;
 692         rndis_iad_descriptor.bFunctionSubClass = rndis_opts->subclass;
 693         rndis_iad_descriptor.bFunctionProtocol = rndis_opts->protocol;
 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         if (cdev->use_os_string)
 731                 f->os_desc_table[0].if_id =
 732                         rndis_iad_descriptor.bFirstInterface;
 733 
 734         status = usb_interface_id(c, f);
 735         if (status < 0)
 736                 goto fail;
 737         rndis->data_id = status;
 738 
 739         rndis_data_intf.bInterfaceNumber = status;
 740         rndis_union_desc.bSlaveInterface0 = status;
 741 
 742         status = -ENODEV;
 743 
 744         /* allocate instance-specific endpoints */
 745         ep = usb_ep_autoconfig(cdev->gadget, &fs_in_desc);
 746         if (!ep)
 747                 goto fail;
 748         rndis->port.in_ep = ep;
 749 
 750         ep = usb_ep_autoconfig(cdev->gadget, &fs_out_desc);
 751         if (!ep)
 752                 goto fail;
 753         rndis->port.out_ep = ep;
 754 
 755         /* NOTE:  a status/notification endpoint is, strictly speaking,
 756          * optional.  We don't treat it that way though!  It's simpler,
 757          * and some newer profiles don't treat it as optional.
 758          */
 759         ep = usb_ep_autoconfig(cdev->gadget, &fs_notify_desc);
 760         if (!ep)
 761                 goto fail;
 762         rndis->notify = ep;
 763 
 764         status = -ENOMEM;
 765 
 766         /* allocate notification request and buffer */
 767         rndis->notify_req = usb_ep_alloc_request(ep, GFP_KERNEL);
 768         if (!rndis->notify_req)
 769                 goto fail;
 770         rndis->notify_req->buf = kmalloc(STATUS_BYTECOUNT, GFP_KERNEL);
 771         if (!rndis->notify_req->buf)
 772                 goto fail;
 773         rndis->notify_req->length = STATUS_BYTECOUNT;
 774         rndis->notify_req->context = rndis;
 775         rndis->notify_req->complete = rndis_response_complete;
 776 
 777         /* support all relevant hardware speeds... we expect that when
 778          * hardware is dual speed, all bulk-capable endpoints work at
 779          * both speeds
 780          */
 781         hs_in_desc.bEndpointAddress = fs_in_desc.bEndpointAddress;
 782         hs_out_desc.bEndpointAddress = fs_out_desc.bEndpointAddress;
 783         hs_notify_desc.bEndpointAddress = fs_notify_desc.bEndpointAddress;
 784 
 785         ss_in_desc.bEndpointAddress = fs_in_desc.bEndpointAddress;
 786         ss_out_desc.bEndpointAddress = fs_out_desc.bEndpointAddress;
 787         ss_notify_desc.bEndpointAddress = fs_notify_desc.bEndpointAddress;
 788 
 789         status = usb_assign_descriptors(f, eth_fs_function, eth_hs_function,
 790                         eth_ss_function, NULL);
 791         if (status)
 792                 goto fail;
 793 
 794         rndis->port.open = rndis_open;
 795         rndis->port.close = rndis_close;
 796 
 797         rndis_set_param_medium(rndis->params, RNDIS_MEDIUM_802_3, 0);
 798         rndis_set_host_mac(rndis->params, rndis->ethaddr);
 799 
 800         if (rndis->manufacturer && rndis->vendorID &&
 801                         rndis_set_param_vendor(rndis->params, rndis->vendorID,
 802                                                rndis->manufacturer)) {
 803                 status = -EINVAL;
 804                 goto fail_free_descs;
 805         }
 806 
 807         /* NOTE:  all that is done without knowing or caring about
 808          * the network link ... which is unavailable to this code
 809          * until we're activated via set_alt().
 810          */
 811 
 812         DBG(cdev, "RNDIS: %s speed IN/%s OUT/%s NOTIFY/%s\n",
 813                         gadget_is_superspeed(c->cdev->gadget) ? "super" :
 814                         gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
 815                         rndis->port.in_ep->name, rndis->port.out_ep->name,
 816                         rndis->notify->name);
 817         return 0;
 818 
 819 fail_free_descs:
 820         usb_free_all_descriptors(f);
 821 fail:
 822         kfree(f->os_desc_table);
 823         f->os_desc_n = 0;
 824 
 825         if (rndis->notify_req) {
 826                 kfree(rndis->notify_req->buf);
 827                 usb_ep_free_request(rndis->notify, rndis->notify_req);
 828         }
 829 
 830         ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
 831 
 832         return status;
 833 }
 834 
 835 void rndis_borrow_net(struct usb_function_instance *f, struct net_device *net)
 836 {
 837         struct f_rndis_opts *opts;
 838 
 839         opts = container_of(f, struct f_rndis_opts, func_inst);
 840         if (opts->bound)
 841                 gether_cleanup(netdev_priv(opts->net));
 842         else
 843                 free_netdev(opts->net);
 844         opts->borrowed_net = opts->bound = true;
 845         opts->net = net;
 846 }
 847 EXPORT_SYMBOL_GPL(rndis_borrow_net);
 848 
 849 static inline struct f_rndis_opts *to_f_rndis_opts(struct config_item *item)
 850 {
 851         return container_of(to_config_group(item), struct f_rndis_opts,
 852                             func_inst.group);
 853 }
 854 
 855 /* f_rndis_item_ops */
 856 USB_ETHERNET_CONFIGFS_ITEM(rndis);
 857 
 858 /* f_rndis_opts_dev_addr */
 859 USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(rndis);
 860 
 861 /* f_rndis_opts_host_addr */
 862 USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(rndis);
 863 
 864 /* f_rndis_opts_qmult */
 865 USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(rndis);
 866 
 867 /* f_rndis_opts_ifname */
 868 USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(rndis);
 869 
 870 /* f_rndis_opts_class */
 871 USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(rndis, class);
 872 
 873 /* f_rndis_opts_subclass */
 874 USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(rndis, subclass);
 875 
 876 /* f_rndis_opts_protocol */
 877 USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(rndis, protocol);
 878 
 879 static struct configfs_attribute *rndis_attrs[] = {
 880         &rndis_opts_attr_dev_addr,
 881         &rndis_opts_attr_host_addr,
 882         &rndis_opts_attr_qmult,
 883         &rndis_opts_attr_ifname,
 884         &rndis_opts_attr_class,
 885         &rndis_opts_attr_subclass,
 886         &rndis_opts_attr_protocol,
 887         NULL,
 888 };
 889 
 890 static const struct config_item_type rndis_func_type = {
 891         .ct_item_ops    = &rndis_item_ops,
 892         .ct_attrs       = rndis_attrs,
 893         .ct_owner       = THIS_MODULE,
 894 };
 895 
 896 static void rndis_free_inst(struct usb_function_instance *f)
 897 {
 898         struct f_rndis_opts *opts;
 899 
 900         opts = container_of(f, struct f_rndis_opts, func_inst);
 901         if (!opts->borrowed_net) {
 902                 if (opts->bound)
 903                         gether_cleanup(netdev_priv(opts->net));
 904                 else
 905                         free_netdev(opts->net);
 906         }
 907 
 908         kfree(opts->rndis_interf_group);        /* single VLA chunk */
 909         kfree(opts);
 910 }
 911 
 912 static struct usb_function_instance *rndis_alloc_inst(void)
 913 {
 914         struct f_rndis_opts *opts;
 915         struct usb_os_desc *descs[1];
 916         char *names[1];
 917         struct config_group *rndis_interf_group;
 918 
 919         opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 920         if (!opts)
 921                 return ERR_PTR(-ENOMEM);
 922         opts->rndis_os_desc.ext_compat_id = opts->rndis_ext_compat_id;
 923 
 924         mutex_init(&opts->lock);
 925         opts->func_inst.free_func_inst = rndis_free_inst;
 926         opts->net = gether_setup_default();
 927         if (IS_ERR(opts->net)) {
 928                 struct net_device *net = opts->net;
 929                 kfree(opts);
 930                 return ERR_CAST(net);
 931         }
 932         INIT_LIST_HEAD(&opts->rndis_os_desc.ext_prop);
 933 
 934         opts->class = rndis_iad_descriptor.bFunctionClass;
 935         opts->subclass = rndis_iad_descriptor.bFunctionSubClass;
 936         opts->protocol = rndis_iad_descriptor.bFunctionProtocol;
 937 
 938         descs[0] = &opts->rndis_os_desc;
 939         names[0] = "rndis";
 940         config_group_init_type_name(&opts->func_inst.group, "",
 941                                     &rndis_func_type);
 942         rndis_interf_group =
 943                 usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs,
 944                                                names, THIS_MODULE);
 945         if (IS_ERR(rndis_interf_group)) {
 946                 rndis_free_inst(&opts->func_inst);
 947                 return ERR_CAST(rndis_interf_group);
 948         }
 949         opts->rndis_interf_group = rndis_interf_group;
 950 
 951         return &opts->func_inst;
 952 }
 953 
 954 static void rndis_free(struct usb_function *f)
 955 {
 956         struct f_rndis *rndis;
 957         struct f_rndis_opts *opts;
 958 
 959         rndis = func_to_rndis(f);
 960         rndis_deregister(rndis->params);
 961         opts = container_of(f->fi, struct f_rndis_opts, func_inst);
 962         kfree(rndis);
 963         mutex_lock(&opts->lock);
 964         opts->refcnt--;
 965         mutex_unlock(&opts->lock);
 966 }
 967 
 968 static void rndis_unbind(struct usb_configuration *c, struct usb_function *f)
 969 {
 970         struct f_rndis          *rndis = func_to_rndis(f);
 971 
 972         kfree(f->os_desc_table);
 973         f->os_desc_n = 0;
 974         usb_free_all_descriptors(f);
 975 
 976         kfree(rndis->notify_req->buf);
 977         usb_ep_free_request(rndis->notify, rndis->notify_req);
 978 }
 979 
 980 static struct usb_function *rndis_alloc(struct usb_function_instance *fi)
 981 {
 982         struct f_rndis  *rndis;
 983         struct f_rndis_opts *opts;
 984         struct rndis_params *params;
 985 
 986         /* allocate and initialize one new instance */
 987         rndis = kzalloc(sizeof(*rndis), GFP_KERNEL);
 988         if (!rndis)
 989                 return ERR_PTR(-ENOMEM);
 990 
 991         opts = container_of(fi, struct f_rndis_opts, func_inst);
 992         mutex_lock(&opts->lock);
 993         opts->refcnt++;
 994 
 995         gether_get_host_addr_u8(opts->net, rndis->ethaddr);
 996         rndis->vendorID = opts->vendor_id;
 997         rndis->manufacturer = opts->manufacturer;
 998 
 999         rndis->port.ioport = netdev_priv(opts->net);
1000         mutex_unlock(&opts->lock);
1001         /* RNDIS activates when the host changes this filter */
1002         rndis->port.cdc_filter = 0;
1003 
1004         /* RNDIS has special (and complex) framing */
1005         rndis->port.header_len = sizeof(struct rndis_packet_msg_type);
1006         rndis->port.wrap = rndis_add_header;
1007         rndis->port.unwrap = rndis_rm_hdr;
1008 
1009         rndis->port.func.name = "rndis";
1010         /* descriptors are per-instance copies */
1011         rndis->port.func.bind = rndis_bind;
1012         rndis->port.func.unbind = rndis_unbind;
1013         rndis->port.func.set_alt = rndis_set_alt;
1014         rndis->port.func.setup = rndis_setup;
1015         rndis->port.func.disable = rndis_disable;
1016         rndis->port.func.free_func = rndis_free;
1017 
1018         params = rndis_register(rndis_response_available, rndis);
1019         if (IS_ERR(params)) {
1020                 kfree(rndis);
1021                 return ERR_CAST(params);
1022         }
1023         rndis->params = params;
1024 
1025         return &rndis->port.func;
1026 }
1027 
1028 DECLARE_USB_FUNCTION_INIT(rndis, rndis_alloc_inst, rndis_alloc);
1029 MODULE_LICENSE("GPL");
1030 MODULE_AUTHOR("David Brownell");