+++ /dev/null
-/*
- * This file define the new driver API for Wireless Extensions
- *
- * Version : 3 17.1.02
- *
- * Authors : Jean Tourrilhes - HPL - <jt@hpl.hp.com>
- * Copyright (c) 2001-2002 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 maintainance.
- * o Flexible : it should accomodate 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 prefered 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 */
-
-/***************************** 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 3
-
-/*
- * 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
- */
-
-/**************************** CONSTANTS ****************************/
-
-/* 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_NONE 0x0000 /* No flag so far */
-
-/* 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_POINT 6 /* struct iw_point */
-#define IW_HEADER_TYPE_PARAM 7 /* struct iw_param */
-#define IW_HEADER_TYPE_ADDR 8 /* struct sockaddr */
-#define IW_HEADER_TYPE_QUAL 9 /* 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 */
-/* 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 ;-) */
-};
-
-/*
- * 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
-{
- /* Number of handlers defined (more precisely, index of the
- * last defined handler + 1) */
- __u16 num_standard;
- __u16 num_private;
- /* Number of private arg description */
- __u16 num_private_args;
-
- /* Array of handlers for standard ioctls
- * We will call dev->wireless_handlers->standard[ioctl - SIOCSIWNAME]
- */
- iw_handler * standard;
-
- /* Array of handlers for private ioctls
- * Will call dev->wireless_handlers->private[ioctl - SIOCIWFIRSTPRIV]
- */
- 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... */
- struct iw_priv_args * private_args;
-
- /* In the long term, get_wireless_stats will move from
- * 'struct net_device' to here, to minimise bloat. */
-};
-
-/* ---------------------- 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. */
-
-/**************************** 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 */
-extern int dev_get_wireless_info(char * buffer, char **start, off_t offset,
- int length);
-
-/* Handle IOCTLs, called in net/code/dev.c */
-extern int wireless_process_ioctl(struct ifreq *ifr, unsigned int cmd);
-
-/* Second : functions that may be called by driver modules */
-
-/* Send a single event to user space */
-extern void wireless_send_event(struct net_device * dev,
- unsigned int cmd,
- union iwreq_data * wrqu,
- char * extra);
-
-/* We may need a function to send a stream of events to user space.
- * More on that later... */
-
-/************************* INLINE FUNTIONS *************************/
-/*
- * Function that are so simple that it's more efficient inlining them
- */
-
-/*------------------------------------------------------------------*/
-/*
- * Wrapper to add an Wireless Event to a stream of events.
- */
-static inline char *
-iwe_stream_add_event(char * stream, /* Stream of events */
- char * ends, /* End of stream */
- struct iw_event *iwe, /* Payload */
- int event_len) /* Real size of payload */
-{
- /* Check if it's possible */
- if((stream + event_len) < ends) {
- iwe->len = event_len;
- memcpy(stream, (char *) iwe, event_len);
- stream += event_len;
- }
- return stream;
-}
-
-/*------------------------------------------------------------------*/
-/*
- * Wrapper to add an short Wireless Event containing a pointer to a
- * stream of events.
- */
-static inline char *
-iwe_stream_add_point(char * stream, /* Stream of events */
- char * ends, /* End of stream */
- struct iw_event *iwe, /* Payload */
- char * extra)
-{
- int event_len = IW_EV_POINT_LEN + iwe->u.data.length;
- /* Check if it's possible */
- if((stream + event_len) < ends) {
- iwe->len = event_len;
- memcpy(stream, (char *) iwe, IW_EV_POINT_LEN);
- memcpy(stream + IW_EV_POINT_LEN, extra, iwe->u.data.length);
- stream += event_len;
- }
- return stream;
-}
-
-/*------------------------------------------------------------------*/
-/*
- * 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).
- */
-static inline char *
-iwe_stream_add_value(char * event, /* Event in the stream */
- char * value, /* Value in event */
- char * ends, /* End of stream */
- struct iw_event *iwe, /* Payload */
- int event_len) /* Real size of payload */
-{
- /* Don't duplicate LCP */
- event_len -= IW_EV_LCP_LEN;
-
- /* Check if it's possible */
- if((value + event_len) < ends) {
- /* Add new value */
- memcpy(value, (char *) iwe + IW_EV_LCP_LEN, event_len);
- value += event_len;
- /* Patch LCP */
- iwe->len = value - event;
- memcpy(event, (char *) iwe, IW_EV_LCP_LEN);
- }
- return value;
-}
-
-#endif /* _IW_HANDLER_H */
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