/* SPDX-License-Identifier: GPL-2.0 *//* * This file define the new driver API for Wireless Extensions * * Version :	8	16.3.07 * * Authors :	Jean Tourrilhes - HPL - <jt@hpl.hp.com> * Copyright (c) 2001-2007 Jean Tourrilhes, All Rights Reserved. */ #ifndef _IW_HANDLER_H#define _IW_HANDLER_H /************************** DOCUMENTATION **************************//* * Initial driver API (1996 -> onward) : * ----------------------------------- * The initial API just sends the IOCTL request received from user space * to the driver (via the driver ioctl handler). The driver has to * handle all the rest... * * The initial API also defines a specific handler in struct net_device * to handle wireless statistics. * * The initial APIs served us well and has proven a reasonably good design. * However, there is a few shortcommings : *	o No events, everything is a request to the driver. *	o Large ioctl function in driver with gigantic switch statement *	  (i.e. spaghetti code). *	o Driver has to mess up with copy_to/from_user, and in many cases *	  does it unproperly. Common mistakes are : *		* buffer overflows (no checks or off by one checks) *		* call copy_to/from_user with irq disabled *	o The user space interface is tied to ioctl because of the use *	  copy_to/from_user. * * New driver API (2002 -> onward) : * ------------------------------- * The new driver API is just a bunch of standard functions (handlers), * each handling a specific Wireless Extension. The driver just export * the list of handler it supports, and those will be called apropriately. * * I tried to keep the main advantage of the previous API (simplicity, * efficiency and light weight), and also I provide a good dose of backward * compatibility (most structures are the same, driver can use both API * simultaneously, ...). * Hopefully, I've also addressed the shortcomming of the initial API. * * The advantage of the new API are : *	o Handling of Extensions in driver broken in small contained functions *	o Tighter checks of ioctl before calling the driver *	o Flexible commit strategy (at least, the start of it) *	o Backward compatibility (can be mixed with old API) *	o Driver doesn't have to worry about memory and user-space issues * The last point is important for the following reasons : *	o You are now able to call the new driver API from any API you *		want (including from within other parts of the kernel). *	o Common mistakes are avoided (buffer overflow, user space copy *		with irq disabled and so on). * * The Drawback of the new API are : *	o bloat (especially kernel) *	o need to migrate existing drivers to new API * My initial testing shows that the new API adds around 3kB to the kernel * and save between 0 and 5kB from a typical driver. * Also, as all structures and data types are unchanged, the migration is * quite straightforward (but tedious). * * --- * * The new driver API is defined below in this file. User space should * not be aware of what's happening down there... * * A new kernel wrapper is in charge of validating the IOCTLs and calling * the appropriate driver handler. This is implemented in : *	# net/core/wireless.c * * The driver export the list of handlers in : *	# include/linux/netdevice.h (one place) * * The new driver API is available for WIRELESS_EXT >= 13. * Good luck with migration to the new API ;-) */ /* ---------------------- THE IMPLEMENTATION ---------------------- *//* * Some of the choice I've made are pretty controversials. Defining an * API is very much weighting compromises. This goes into some of the * details and the thinking behind the implementation. * * Implementation goals : * -------------------- * The implementation goals were as follow : *	o Obvious : you should not need a PhD to understand what's happening, *		the benefit is easier maintenance. *	o Flexible : it should accommodate a wide variety of driver *		implementations and be as flexible as the old API. *	o Lean : it should be efficient memory wise to minimise the impact *		on kernel footprint. *	o Transparent to user space : the large number of user space *		applications that use Wireless Extensions should not need *		any modifications. * * Array of functions versus Struct of functions * --------------------------------------------- * 1) Having an array of functions allow the kernel code to access the * handler in a single lookup, which is much more efficient (think hash * table here). * 2) The only drawback is that driver writer may put their handler in * the wrong slot. This is trivial to test (I set the frequency, the * bitrate changes). Once the handler is in the proper slot, it will be * there forever, because the array is only extended at the end. * 3) Backward/forward compatibility : adding new handler just require * extending the array, so you can put newer driver in older kernel * without having to patch the kernel code (and vice versa). * * All handler are of the same generic type * ---------------------------------------- * That's a feature !!! * 1) Having a generic handler allow to have generic code, which is more * efficient. If each of the handler was individually typed I would need * to add a big switch in the kernel (== more bloat). This solution is * more scalable, adding new Wireless Extensions doesn't add new code. * 2) You can use the same handler in different slots of the array. For * hardware, it may be more efficient or logical to handle multiple * Wireless Extensions with a single function, and the API allow you to * do that. (An example would be a single record on the card to control * both bitrate and frequency, the handler would read the old record, * modify it according to info->cmd and rewrite it). * * Functions prototype uses union iwreq_data * ----------------------------------------- * Some would have preferred functions defined this way : *	static int mydriver_ioctl_setrate(struct net_device *dev,  *					  long rate, int auto) * 1) The kernel code doesn't "validate" the content of iwreq_data, and * can't do it (different hardware may have different notion of what a * valid frequency is), so we don't pretend that we do it. * 2) The above form is not extendable. If I want to add a flag (for * example to distinguish setting max rate and basic rate), I would * break the prototype. Using iwreq_data is more flexible. * 3) Also, the above form is not generic (see above). * 4) I don't expect driver developper using the wrong field of the * union (Doh !), so static typechecking doesn't add much value. * 5) Lastly, you can skip the union by doing : *	static int mydriver_ioctl_setrate(struct net_device *dev, *					  struct iw_request_info *info, *					  struct iw_param *rrq, *					  char *extra) * And then adding the handler in the array like this : *        (iw_handler) mydriver_ioctl_setrate,             // SIOCSIWRATE * * Using functions and not a registry * ---------------------------------- * Another implementation option would have been for every instance to * define a registry (a struct containing all the Wireless Extensions) * and only have a function to commit the registry to the hardware. * 1) This approach can be emulated by the current code, but not * vice versa. * 2) Some drivers don't keep any configuration in the driver, for them * adding such a registry would be a significant bloat. * 3) The code to translate from Wireless Extension to native format is * needed anyway, so it would not reduce significantely the amount of code. * 4) The current approach only selectively translate Wireless Extensions * to native format and only selectively set, whereas the registry approach * would require to translate all WE and set all parameters for any single * change. * 5) For many Wireless Extensions, the GET operation return the current * dynamic value, not the value that was set. * * This header is <net/iw_handler.h> * --------------------------------- * 1) This header is kernel space only and should not be exported to * user space. Headers in "include/linux/" are exported, headers in * "include/net/" are not. * * Mixed 32/64 bit issues * ---------------------- * The Wireless Extensions are designed to be 64 bit clean, by using only * datatypes with explicit storage size. * There are some issues related to kernel and user space using different * memory model, and in particular 64bit kernel with 32bit user space. * The problem is related to struct iw_point, that contains a pointer * that *may* need to be translated. * This is quite messy. The new API doesn't solve this problem (it can't), * but is a step in the right direction : * 1) Meta data about each ioctl is easily available, so we know what type * of translation is needed. * 2) The move of data between kernel and user space is only done in a single * place in the kernel, so adding specific hooks in there is possible. * 3) In the long term, it allows to move away from using ioctl as the * user space API. * * So many comments and so few code * -------------------------------- * That's a feature. Comments won't bloat the resulting kernel binary. */ /***************************** INCLUDES *****************************/ #include <linux/wireless.h>		/* IOCTL user space API */#include <linux/if_ether.h> /***************************** VERSION *****************************//* * This constant is used to know which version of the driver API is * available. Hopefully, this will be pretty stable and no changes * will be needed... * I just plan to increment with each new version. */#define IW_HANDLER_VERSION	8 /* * Changes : * * V2 to V3 * -------- *	- Move event definition in <linux/wireless.h> *	- Add Wireless Event support : *		o wireless_send_event() prototype *		o iwe_stream_add_event/point() inline functions * V3 to V4 * -------- *	- Reshuffle IW_HEADER_TYPE_XXX to map IW_PRIV_TYPE_XXX changes * * V4 to V5 * -------- *	- Add new spy support : struct iw_spy_data & prototypes * * V5 to V6 * -------- *	- Change the way we get to spy_data method for added safety *	- Remove spy #ifdef, they are always on -> cleaner code *	- Add IW_DESCR_FLAG_NOMAX flag for very large requests *	- Start migrating get_wireless_stats to struct iw_handler_def * * V6 to V7 * -------- *	- Add struct ieee80211_device pointer in struct iw_public_data *	- Remove (struct iw_point *)->pointer from events and streams *	- Remove spy_offset from struct iw_handler_def *	- Add "check" version of event macros for ieee802.11 stack * * V7 to V8 * ---------- *	- Prevent leaking of kernel space in stream on 64 bits. */ /**************************** CONSTANTS ****************************/ /* Enhanced spy support available */#define IW_WIRELESS_SPY#define IW_WIRELESS_THRSPY /* Special error message for the driver to indicate that we * should do a commit after return from the iw_handler */#define EIWCOMMIT	EINPROGRESS /* Flags available in struct iw_request_info */#define IW_REQUEST_FLAG_COMPAT	0x0001	/* Compat ioctl call */ /* Type of headers we know about (basically union iwreq_data) */#define IW_HEADER_TYPE_NULL	0	/* Not available */#define IW_HEADER_TYPE_CHAR	2	/* char [IFNAMSIZ] */#define IW_HEADER_TYPE_UINT	4	/* __u32 */#define IW_HEADER_TYPE_FREQ	5	/* struct iw_freq */#define IW_HEADER_TYPE_ADDR	6	/* struct sockaddr */#define IW_HEADER_TYPE_POINT	8	/* struct iw_point */#define IW_HEADER_TYPE_PARAM	9	/* struct iw_param */#define IW_HEADER_TYPE_QUAL	10	/* struct iw_quality */ /* Handling flags *//* Most are not implemented. I just use them as a reminder of some * cool features we might need one day ;-) */#define IW_DESCR_FLAG_NONE	0x0000	/* Obvious *//* Wrapper level flags */#define IW_DESCR_FLAG_DUMP	0x0001	/* Not part of the dump command */#define IW_DESCR_FLAG_EVENT	0x0002	/* Generate an event on SET */#define IW_DESCR_FLAG_RESTRICT	0x0004	/* GET : request is ROOT only */				/* SET : Omit payload from generated iwevent */#define IW_DESCR_FLAG_NOMAX	0x0008	/* GET : no limit on request size *//* Driver level flags */#define IW_DESCR_FLAG_WAIT	0x0100	/* Wait for driver event */ /****************************** TYPES ******************************/ /* ----------------------- WIRELESS HANDLER ----------------------- *//* * A wireless handler is just a standard function, that looks like the * ioctl handler. * We also define there how a handler list look like... As the Wireless * Extension space is quite dense, we use a simple array, which is faster * (that's the perfect hash table ;-). */ /* * Meta data about the request passed to the iw_handler. * Most handlers can safely ignore what's in there. * The 'cmd' field might come handy if you want to use the same handler * for multiple command... * This struct is also my long term insurance. I can add new fields here * without breaking the prototype of iw_handler... */struct iw_request_info {	__u16		cmd;		/* Wireless Extension command */	__u16		flags;		/* More to come ;-) */}; struct net_device; /* * This is how a function handling a Wireless Extension should look * like (both get and set, standard and private). */typedef int (*iw_handler)(struct net_device *dev, struct iw_request_info *info,			  union iwreq_data *wrqu, char *extra); /* * This define all the handler that the driver export. * As you need only one per driver type, please use a static const * shared by all driver instances... Same for the members... * This will be linked from net_device in <linux/netdevice.h> */struct iw_handler_def { 	/* Array of handlers for standard ioctls	 * We will call dev->wireless_handlers->standard[ioctl - SIOCIWFIRST]	 */	const iw_handler *	standard;	/* Number of handlers defined (more precisely, index of the	 * last defined handler + 1) */	__u16			num_standard; #ifdef CONFIG_WEXT_PRIV	__u16			num_private;	/* Number of private arg description */	__u16			num_private_args;	/* Array of handlers for private ioctls	 * Will call dev->wireless_handlers->private[ioctl - SIOCIWFIRSTPRIV]	 */	const iw_handler *	private; 	/* Arguments of private handler. This one is just a list, so you	 * can put it in any order you want and should not leave holes...	 * We will automatically export that to user space... */	const struct iw_priv_args *	private_args;#endif 	/* New location of get_wireless_stats, to de-bloat struct net_device.	 * The old pointer in struct net_device will be gradually phased	 * out, and drivers are encouraged to use this one... */	struct iw_statistics*	(*get_wireless_stats)(struct net_device *dev);}; /* ---------------------- IOCTL DESCRIPTION ---------------------- *//* * One of the main goal of the new interface is to deal entirely with * user space/kernel space memory move. * For that, we need to know : *	o if iwreq is a pointer or contain the full data *	o what is the size of the data to copy * * For private IOCTLs, we use the same rules as used by iwpriv and * defined in struct iw_priv_args. * * For standard IOCTLs, things are quite different and we need to * use the stuctures below. Actually, this struct is also more * efficient, but that's another story... */ /* * Describe how a standard IOCTL looks like. */struct iw_ioctl_description {	__u8	header_type;		/* NULL, iw_point or other */	__u8	token_type;		/* Future */	__u16	token_size;		/* Granularity of payload */	__u16	min_tokens;		/* Min acceptable token number */	__u16	max_tokens;		/* Max acceptable token number */	__u32	flags;			/* Special handling of the request */}; /* Need to think of short header translation table. Later. */ /* --------------------- ENHANCED SPY SUPPORT --------------------- *//* * In the old days, the driver was handling spy support all by itself. * Now, the driver can delegate this task to Wireless Extensions. * It needs to include this struct in its private part and use the * standard spy iw_handler. */ /* * Instance specific spy data, i.e. addresses spied and quality for them. */struct iw_spy_data {	/* --- Standard spy support --- */	int			spy_number;	u_char			spy_address[IW_MAX_SPY][ETH_ALEN];	struct iw_quality	spy_stat[IW_MAX_SPY];	/* --- Enhanced spy support (event) */	struct iw_quality	spy_thr_low;	/* Low threshold */	struct iw_quality	spy_thr_high;	/* High threshold */	u_char			spy_thr_under[IW_MAX_SPY];}; /* --------------------- DEVICE WIRELESS DATA --------------------- *//* * This is all the wireless data specific to a device instance that * is managed by the core of Wireless Extensions or the 802.11 layer. * We only keep pointer to those structures, so that a driver is free * to share them between instances. * This structure should be initialised before registering the device. * Access to this data follow the same rules as any other struct net_device * data (i.e. valid as long as struct net_device exist, same locking rules). *//* Forward declaration */struct libipw_device;/* The struct */struct iw_public_data {	/* Driver enhanced spy support */	struct iw_spy_data *		spy_data;	/* Legacy structure managed by the ipw2x00-specific IEEE 802.11 layer */	struct libipw_device *		libipw;}; /**************************** PROTOTYPES ****************************//* * Functions part of the Wireless Extensions (defined in net/core/wireless.c). * Those may be called only within the kernel. */ /* First : function strictly used inside the kernel */ /* Handle /proc/net/wireless, called in net/code/dev.c */int dev_get_wireless_info(char *buffer, char **start, off_t offset, int length); /* Second : functions that may be called by driver modules */ /* Send a single event to user space */void wireless_send_event(struct net_device *dev, unsigned int cmd,			 union iwreq_data *wrqu, const char *extra);#ifdef CONFIG_WEXT_CORE/* flush all previous wext events - if work is done from netdev notifiers */void wireless_nlevent_flush(void);#elsestatic inline void wireless_nlevent_flush(void) {}#endif /* We may need a function to send a stream of events to user space. * More on that later... */ /* Standard handler for SIOCSIWSPY */int iw_handler_set_spy(struct net_device *dev, struct iw_request_info *info,		       union iwreq_data *wrqu, char *extra);/* Standard handler for SIOCGIWSPY */int iw_handler_get_spy(struct net_device *dev, struct iw_request_info *info,		       union iwreq_data *wrqu, char *extra);/* Standard handler for SIOCSIWTHRSPY */int iw_handler_set_thrspy(struct net_device *dev, struct iw_request_info *info,			  union iwreq_data *wrqu, char *extra);/* Standard handler for SIOCGIWTHRSPY */int iw_handler_get_thrspy(struct net_device *dev, struct iw_request_info *info,			  union iwreq_data *wrqu, char *extra);/* Driver call to update spy records */void wireless_spy_update(struct net_device *dev, unsigned char *address,			 struct iw_quality *wstats); /************************* INLINE FUNTIONS *************************//* * Function that are so simple that it's more efficient inlining them */ static inline int iwe_stream_lcp_len(struct iw_request_info *info){#ifdef CONFIG_COMPAT	if (info->flags & IW_REQUEST_FLAG_COMPAT)		return IW_EV_COMPAT_LCP_LEN;#endif	return IW_EV_LCP_LEN;} static inline int iwe_stream_point_len(struct iw_request_info *info){#ifdef CONFIG_COMPAT	if (info->flags & IW_REQUEST_FLAG_COMPAT)		return IW_EV_COMPAT_POINT_LEN;#endif	return IW_EV_POINT_LEN;} static inline int iwe_stream_event_len_adjust(struct iw_request_info *info,					      int event_len){#ifdef CONFIG_COMPAT	if (info->flags & IW_REQUEST_FLAG_COMPAT) {		event_len -= IW_EV_LCP_LEN;		event_len += IW_EV_COMPAT_LCP_LEN;	}#endif

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