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 /* 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 structures 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);
 #else
 static 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
 
     return event_len;
 }
 
 /*------------------------------------------------------------------*/
 /*
  * Wrapper to add an Wireless Event to a stream of events.
  */
 char *iwe_stream_add_event(struct iw_request_info *info, char *stream,
                char *ends, struct iw_event *iwe, int event_len);
 
 static inline char *
 iwe_stream_add_event_check(struct iw_request_info *info, char *stream,
                char *ends, struct iw_event *iwe, int event_len)
 {
     char *res = iwe_stream_add_event(info, stream, ends, iwe, event_len);
 
     if (res == stream)
         return ERR_PTR(-E2BIG);
     return res;
 }
 
 /*------------------------------------------------------------------*/
 /*
  * Wrapper to add an short Wireless Event containing a pointer to a
  * stream of events.
  */
 char *iwe_stream_add_point(struct iw_request_info *info, char *stream,
                char *ends, struct iw_event *iwe, char *extra);
 
 static inline char *
 iwe_stream_add_point_check(struct iw_request_info *info, char *stream,
                char *ends, struct iw_event *iwe, char *extra)
 {
     char *res = iwe_stream_add_point(info, stream, ends, iwe, extra);
 
     if (res == stream)
         return ERR_PTR(-E2BIG);
     return res;
 }
 
 /*------------------------------------------------------------------*/
 /*
  * Wrapper to add a value to a Wireless Event in a stream of events.
  * Be careful, this one is tricky to use properly :
  * At the first run, you need to have (value = event + IW_EV_LCP_LEN).
  */
 char *iwe_stream_add_value(struct iw_request_info *info, char *event,
                char *value, char *ends, struct iw_event *iwe,
                int event_len);
 
 #endif  /* _IW_HANDLER_H */

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