// SPDX-License-Identifier: GPL-2.0+ /* * f_rndis.c -- RNDIS link function driver * * Copyright (C) 2003-2005,2008 David Brownell * Copyright (C) 2003-2004 Robert Schwebel, Benedikt Spranger * Copyright (C) 2008 Nokia Corporation * Copyright (C) 2009 Samsung Electronics * Author: Michal Nazarewicz ([email protected]) */ /* #define VERBOSE_DEBUG */ #include <linux/slab.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/device.h> #include <linux/etherdevice.h> #include <linux/atomic.h> #include "u_ether.h" #include "u_ether_configfs.h" #include "u_rndis.h" #include "rndis.h" #include "configfs.h" /* * This function is an RNDIS Ethernet port -- a Microsoft protocol that's * been promoted instead of the standard CDC Ethernet. The published RNDIS * spec is ambiguous, incomplete, and needlessly complex. Variants such as * ActiveSync have even worse status in terms of specification. * * In short: it's a protocol controlled by (and for) Microsoft, not for an * Open ecosystem or markets. Linux supports it *only* because Microsoft * doesn't support the CDC Ethernet standard. * * The RNDIS data transfer model is complex, with multiple Ethernet packets * per USB message, and out of band data. The control model is built around * what's essentially an "RNDIS RPC" protocol. It's all wrapped in a CDC ACM * (modem, not Ethernet) veneer, with those ACM descriptors being entirely * useless (they're ignored). RNDIS expects to be the only function in its * configuration, so it's no real help if you need composite devices; and * it expects to be the first configuration too. * * There is a single technical advantage of RNDIS over CDC Ethernet, if you * discount the fluff that its RPC can be made to deliver: it doesn't need * a NOP altsetting for the data interface. That lets it work on some of the * "so smart it's stupid" hardware which takes over configuration changes * from the software, and adds restrictions like "no altsettings". * * Unfortunately MSFT's RNDIS drivers are buggy. They hang or oops, and * have all sorts of contrary-to-specification oddities that can prevent * them from working sanely. Since bugfixes (or accurate specs, letting * Linux work around those bugs) are unlikely to ever come from MSFT, you * may want to avoid using RNDIS on purely operational grounds. * * Omissions from the RNDIS 1.0 specification include: * * - Power management ... references data that's scattered around lots * of other documentation, which is incorrect/incomplete there too. * * - There are various undocumented protocol requirements, like the need * to send garbage in some control-OUT messages. * * - MS-Windows drivers sometimes emit undocumented requests. */ struct f_rndis { … }; static inline struct f_rndis *func_to_rndis(struct usb_function *f) { … } /*-------------------------------------------------------------------------*/ /* */ #define RNDIS_STATUS_INTERVAL_MS … #define STATUS_BYTECOUNT … /* interface descriptor: */ static struct usb_interface_descriptor rndis_control_intf = …; static struct usb_cdc_header_desc header_desc = …; static struct usb_cdc_call_mgmt_descriptor call_mgmt_descriptor = …; static struct usb_cdc_acm_descriptor rndis_acm_descriptor = …; static struct usb_cdc_union_desc rndis_union_desc = …; /* the data interface has two bulk endpoints */ static struct usb_interface_descriptor rndis_data_intf = …; static struct usb_interface_assoc_descriptor rndis_iad_descriptor = …; /* full speed support: */ static struct usb_endpoint_descriptor fs_notify_desc = …; static struct usb_endpoint_descriptor fs_in_desc = …; static struct usb_endpoint_descriptor fs_out_desc = …; static struct usb_descriptor_header *eth_fs_function[] = …; /* high speed support: */ static struct usb_endpoint_descriptor hs_notify_desc = …; static struct usb_endpoint_descriptor hs_in_desc = …; static struct usb_endpoint_descriptor hs_out_desc = …; static struct usb_descriptor_header *eth_hs_function[] = …; /* super speed support: */ static struct usb_endpoint_descriptor ss_notify_desc = …; static struct usb_ss_ep_comp_descriptor ss_intr_comp_desc = …; static struct usb_endpoint_descriptor ss_in_desc = …; static struct usb_endpoint_descriptor ss_out_desc = …; static struct usb_ss_ep_comp_descriptor ss_bulk_comp_desc = …; static struct usb_descriptor_header *eth_ss_function[] = …; /* string descriptors: */ static struct usb_string rndis_string_defs[] = …; static struct usb_gadget_strings rndis_string_table = …; static struct usb_gadget_strings *rndis_strings[] = …; /*-------------------------------------------------------------------------*/ static struct sk_buff *rndis_add_header(struct gether *port, struct sk_buff *skb) { … } static void rndis_response_available(void *_rndis) { … } static void rndis_response_complete(struct usb_ep *ep, struct usb_request *req) { … } static void rndis_command_complete(struct usb_ep *ep, struct usb_request *req) { … } static int rndis_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl) { … } static int rndis_set_alt(struct usb_function *f, unsigned intf, unsigned alt) { … } static void rndis_disable(struct usb_function *f) { … } /*-------------------------------------------------------------------------*/ /* * This isn't quite the same mechanism as CDC Ethernet, since the * notification scheme passes less data, but the same set of link * states must be tested. A key difference is that altsettings are * not used to tell whether the link should send packets or not. */ static void rndis_open(struct gether *geth) { … } static void rndis_close(struct gether *geth) { … } /*-------------------------------------------------------------------------*/ /* Some controllers can't support RNDIS ... */ static inline bool can_support_rndis(struct usb_configuration *c) { … } /* ethernet function driver setup/binding */ static int rndis_bind(struct usb_configuration *c, struct usb_function *f) { … } void rndis_borrow_net(struct usb_function_instance *f, struct net_device *net) { … } EXPORT_SYMBOL_GPL(…); static inline struct f_rndis_opts *to_f_rndis_opts(struct config_item *item) { … } /* f_rndis_item_ops */ USB_ETHERNET_CONFIGFS_ITEM(…); /* f_rndis_opts_dev_addr */ USB_ETHERNET_CONFIGFS_ITEM_ATTR_DEV_ADDR(…); /* f_rndis_opts_host_addr */ USB_ETHERNET_CONFIGFS_ITEM_ATTR_HOST_ADDR(…); /* f_rndis_opts_qmult */ USB_ETHERNET_CONFIGFS_ITEM_ATTR_QMULT(…); /* f_rndis_opts_ifname */ USB_ETHERNET_CONFIGFS_ITEM_ATTR_IFNAME(…); /* f_rndis_opts_class */ USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(…); /* f_rndis_opts_subclass */ USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(…); /* f_rndis_opts_protocol */ USB_ETHER_CONFIGFS_ITEM_ATTR_U8_RW(…); static struct configfs_attribute *rndis_attrs[] = …; static const struct config_item_type rndis_func_type = …; static void rndis_free_inst(struct usb_function_instance *f) { … } static struct usb_function_instance *rndis_alloc_inst(void) { … } static void rndis_free(struct usb_function *f) { … } static void rndis_unbind(struct usb_configuration *c, struct usb_function *f) { … } static struct usb_function *rndis_alloc(struct usb_function_instance *fi) { … } DECLARE_USB_FUNCTION_INIT(rndis, rndis_alloc_inst, rndis_alloc); MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …; MODULE_AUTHOR(…) …;
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