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552 lines
21 KiB
552 lines
21 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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/* |
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* This file define the new driver API for Wireless Extensions |
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* |
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* Version : 8 16.3.07 |
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* |
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* Authors : Jean Tourrilhes - HPL - <[email protected]> |
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* Copyright (c) 2001-2007 Jean Tourrilhes, All Rights Reserved. |
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*/ |
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#ifndef _IW_HANDLER_H |
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#define _IW_HANDLER_H |
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/************************** DOCUMENTATION **************************/ |
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/* |
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* Initial driver API (1996 -> onward) : |
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* ----------------------------------- |
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* The initial API just sends the IOCTL request received from user space |
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* to the driver (via the driver ioctl handler). The driver has to |
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* handle all the rest... |
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* |
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* The initial API also defines a specific handler in struct net_device |
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* to handle wireless statistics. |
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* |
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* The initial APIs served us well and has proven a reasonably good design. |
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* However, there is a few shortcommings : |
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* o No events, everything is a request to the driver. |
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* o Large ioctl function in driver with gigantic switch statement |
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* (i.e. spaghetti code). |
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* o Driver has to mess up with copy_to/from_user, and in many cases |
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* does it unproperly. Common mistakes are : |
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* * buffer overflows (no checks or off by one checks) |
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* * call copy_to/from_user with irq disabled |
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* o The user space interface is tied to ioctl because of the use |
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* copy_to/from_user. |
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* |
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* New driver API (2002 -> onward) : |
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* ------------------------------- |
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* The new driver API is just a bunch of standard functions (handlers), |
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* each handling a specific Wireless Extension. The driver just export |
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* the list of handler it supports, and those will be called apropriately. |
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* |
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* I tried to keep the main advantage of the previous API (simplicity, |
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* efficiency and light weight), and also I provide a good dose of backward |
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* compatibility (most structures are the same, driver can use both API |
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* simultaneously, ...). |
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* Hopefully, I've also addressed the shortcomming of the initial API. |
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* |
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* The advantage of the new API are : |
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* o Handling of Extensions in driver broken in small contained functions |
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* o Tighter checks of ioctl before calling the driver |
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* o Flexible commit strategy (at least, the start of it) |
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* o Backward compatibility (can be mixed with old API) |
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* o Driver doesn't have to worry about memory and user-space issues |
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* The last point is important for the following reasons : |
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* o You are now able to call the new driver API from any API you |
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* want (including from within other parts of the kernel). |
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* o Common mistakes are avoided (buffer overflow, user space copy |
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* with irq disabled and so on). |
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* |
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* The Drawback of the new API are : |
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* o bloat (especially kernel) |
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* o need to migrate existing drivers to new API |
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* My initial testing shows that the new API adds around 3kB to the kernel |
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* and save between 0 and 5kB from a typical driver. |
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* Also, as all structures and data types are unchanged, the migration is |
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* quite straightforward (but tedious). |
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* |
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* --- |
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* |
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* The new driver API is defined below in this file. User space should |
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* not be aware of what's happening down there... |
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* |
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* A new kernel wrapper is in charge of validating the IOCTLs and calling |
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* the appropriate driver handler. This is implemented in : |
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* # net/core/wireless.c |
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* |
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* The driver export the list of handlers in : |
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* # include/linux/netdevice.h (one place) |
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* |
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* The new driver API is available for WIRELESS_EXT >= 13. |
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* Good luck with migration to the new API ;-) |
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*/ |
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/* ---------------------- THE IMPLEMENTATION ---------------------- */ |
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/* |
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* Some of the choice I've made are pretty controversials. Defining an |
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* API is very much weighting compromises. This goes into some of the |
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* details and the thinking behind the implementation. |
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* |
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* Implementation goals : |
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* -------------------- |
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* The implementation goals were as follow : |
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* o Obvious : you should not need a PhD to understand what's happening, |
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* the benefit is easier maintenance. |
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* o Flexible : it should accommodate a wide variety of driver |
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* implementations and be as flexible as the old API. |
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* o Lean : it should be efficient memory wise to minimise the impact |
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* on kernel footprint. |
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* o Transparent to user space : the large number of user space |
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* applications that use Wireless Extensions should not need |
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* any modifications. |
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* |
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* Array of functions versus Struct of functions |
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* --------------------------------------------- |
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* 1) Having an array of functions allow the kernel code to access the |
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* handler in a single lookup, which is much more efficient (think hash |
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* table here). |
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* 2) The only drawback is that driver writer may put their handler in |
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* the wrong slot. This is trivial to test (I set the frequency, the |
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* bitrate changes). Once the handler is in the proper slot, it will be |
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* there forever, because the array is only extended at the end. |
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* 3) Backward/forward compatibility : adding new handler just require |
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* extending the array, so you can put newer driver in older kernel |
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* without having to patch the kernel code (and vice versa). |
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* |
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* All handler are of the same generic type |
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* ---------------------------------------- |
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* That's a feature !!! |
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* 1) Having a generic handler allow to have generic code, which is more |
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* efficient. If each of the handler was individually typed I would need |
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* to add a big switch in the kernel (== more bloat). This solution is |
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* more scalable, adding new Wireless Extensions doesn't add new code. |
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* 2) You can use the same handler in different slots of the array. For |
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* hardware, it may be more efficient or logical to handle multiple |
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* Wireless Extensions with a single function, and the API allow you to |
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* do that. (An example would be a single record on the card to control |
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* both bitrate and frequency, the handler would read the old record, |
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* modify it according to info->cmd and rewrite it). |
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* |
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* Functions prototype uses union iwreq_data |
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* ----------------------------------------- |
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* Some would have preferred functions defined this way : |
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* static int mydriver_ioctl_setrate(struct net_device *dev, |
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* long rate, int auto) |
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* 1) The kernel code doesn't "validate" the content of iwreq_data, and |
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* can't do it (different hardware may have different notion of what a |
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* valid frequency is), so we don't pretend that we do it. |
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* 2) The above form is not extendable. If I want to add a flag (for |
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* example to distinguish setting max rate and basic rate), I would |
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* break the prototype. Using iwreq_data is more flexible. |
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* 3) Also, the above form is not generic (see above). |
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* 4) I don't expect driver developper using the wrong field of the |
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* union (Doh !), so static typechecking doesn't add much value. |
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* 5) Lastly, you can skip the union by doing : |
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* static int mydriver_ioctl_setrate(struct net_device *dev, |
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* struct iw_request_info *info, |
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* struct iw_param *rrq, |
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* char *extra) |
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* And then adding the handler in the array like this : |
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* (iw_handler) mydriver_ioctl_setrate, // SIOCSIWRATE |
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* |
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* Using functions and not a registry |
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* ---------------------------------- |
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* Another implementation option would have been for every instance to |
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* define a registry (a struct containing all the Wireless Extensions) |
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* and only have a function to commit the registry to the hardware. |
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* 1) This approach can be emulated by the current code, but not |
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* vice versa. |
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* 2) Some drivers don't keep any configuration in the driver, for them |
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* adding such a registry would be a significant bloat. |
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* 3) The code to translate from Wireless Extension to native format is |
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* needed anyway, so it would not reduce significantely the amount of code. |
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* 4) The current approach only selectively translate Wireless Extensions |
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* to native format and only selectively set, whereas the registry approach |
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* would require to translate all WE and set all parameters for any single |
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* change. |
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* 5) For many Wireless Extensions, the GET operation return the current |
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* dynamic value, not the value that was set. |
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* |
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* This header is <net/iw_handler.h> |
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* --------------------------------- |
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* 1) This header is kernel space only and should not be exported to |
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* user space. Headers in "include/linux/" are exported, headers in |
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* "include/net/" are not. |
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* |
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* Mixed 32/64 bit issues |
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* ---------------------- |
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* The Wireless Extensions are designed to be 64 bit clean, by using only |
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* datatypes with explicit storage size. |
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* There are some issues related to kernel and user space using different |
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* memory model, and in particular 64bit kernel with 32bit user space. |
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* The problem is related to struct iw_point, that contains a pointer |
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* that *may* need to be translated. |
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* This is quite messy. The new API doesn't solve this problem (it can't), |
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* but is a step in the right direction : |
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* 1) Meta data about each ioctl is easily available, so we know what type |
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* of translation is needed. |
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* 2) The move of data between kernel and user space is only done in a single |
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* place in the kernel, so adding specific hooks in there is possible. |
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* 3) In the long term, it allows to move away from using ioctl as the |
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* user space API. |
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* |
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* So many comments and so few code |
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* -------------------------------- |
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* That's a feature. Comments won't bloat the resulting kernel binary. |
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*/ |
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/***************************** INCLUDES *****************************/ |
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#include <linux/wireless.h> /* IOCTL user space API */ |
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#include <linux/if_ether.h> |
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/***************************** VERSION *****************************/ |
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/* |
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* This constant is used to know which version of the driver API is |
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* available. Hopefully, this will be pretty stable and no changes |
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* will be needed... |
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* I just plan to increment with each new version. |
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*/ |
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#define IW_HANDLER_VERSION 8 |
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/* |
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* Changes : |
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* |
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* V2 to V3 |
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* -------- |
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* - Move event definition in <linux/wireless.h> |
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* - Add Wireless Event support : |
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* o wireless_send_event() prototype |
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* o iwe_stream_add_event/point() inline functions |
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* V3 to V4 |
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* -------- |
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* - Reshuffle IW_HEADER_TYPE_XXX to map IW_PRIV_TYPE_XXX changes |
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* |
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* V4 to V5 |
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* -------- |
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* - Add new spy support : struct iw_spy_data & prototypes |
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* |
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* V5 to V6 |
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* -------- |
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* - Change the way we get to spy_data method for added safety |
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* - Remove spy #ifdef, they are always on -> cleaner code |
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* - Add IW_DESCR_FLAG_NOMAX flag for very large requests |
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* - Start migrating get_wireless_stats to struct iw_handler_def |
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* |
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* V6 to V7 |
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* -------- |
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* - Add struct ieee80211_device pointer in struct iw_public_data |
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* - Remove (struct iw_point *)->pointer from events and streams |
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* - Remove spy_offset from struct iw_handler_def |
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* - Add "check" version of event macros for ieee802.11 stack |
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* |
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* V7 to V8 |
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* ---------- |
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* - Prevent leaking of kernel space in stream on 64 bits. |
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*/ |
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/**************************** CONSTANTS ****************************/ |
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/* Enhanced spy support available */ |
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#define IW_WIRELESS_SPY |
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#define IW_WIRELESS_THRSPY |
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/* Special error message for the driver to indicate that we |
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* should do a commit after return from the iw_handler */ |
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#define EIWCOMMIT EINPROGRESS |
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/* Flags available in struct iw_request_info */ |
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#define IW_REQUEST_FLAG_COMPAT 0x0001 /* Compat ioctl call */ |
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/* Type of headers we know about (basically union iwreq_data) */ |
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#define IW_HEADER_TYPE_NULL 0 /* Not available */ |
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#define IW_HEADER_TYPE_CHAR 2 /* char [IFNAMSIZ] */ |
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#define IW_HEADER_TYPE_UINT 4 /* __u32 */ |
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#define IW_HEADER_TYPE_FREQ 5 /* struct iw_freq */ |
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#define IW_HEADER_TYPE_ADDR 6 /* struct sockaddr */ |
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#define IW_HEADER_TYPE_POINT 8 /* struct iw_point */ |
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#define IW_HEADER_TYPE_PARAM 9 /* struct iw_param */ |
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#define IW_HEADER_TYPE_QUAL 10 /* struct iw_quality */ |
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/* Handling flags */ |
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/* Most are not implemented. I just use them as a reminder of some |
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* cool features we might need one day ;-) */ |
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#define IW_DESCR_FLAG_NONE 0x0000 /* Obvious */ |
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/* Wrapper level flags */ |
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#define IW_DESCR_FLAG_DUMP 0x0001 /* Not part of the dump command */ |
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#define IW_DESCR_FLAG_EVENT 0x0002 /* Generate an event on SET */ |
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#define IW_DESCR_FLAG_RESTRICT 0x0004 /* GET : request is ROOT only */ |
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/* SET : Omit payload from generated iwevent */ |
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#define IW_DESCR_FLAG_NOMAX 0x0008 /* GET : no limit on request size */ |
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/* Driver level flags */ |
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#define IW_DESCR_FLAG_WAIT 0x0100 /* Wait for driver event */ |
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/****************************** TYPES ******************************/ |
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/* ----------------------- WIRELESS HANDLER ----------------------- */ |
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/* |
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* A wireless handler is just a standard function, that looks like the |
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* ioctl handler. |
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* We also define there how a handler list look like... As the Wireless |
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* Extension space is quite dense, we use a simple array, which is faster |
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* (that's the perfect hash table ;-). |
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*/ |
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/* |
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* Meta data about the request passed to the iw_handler. |
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* Most handlers can safely ignore what's in there. |
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* The 'cmd' field might come handy if you want to use the same handler |
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* for multiple command... |
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* This struct is also my long term insurance. I can add new fields here |
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* without breaking the prototype of iw_handler... |
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*/ |
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struct iw_request_info { |
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__u16 cmd; /* Wireless Extension command */ |
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__u16 flags; /* More to come ;-) */ |
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}; |
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struct net_device; |
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/* |
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* This is how a function handling a Wireless Extension should look |
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* like (both get and set, standard and private). |
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*/ |
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typedef int (*iw_handler)(struct net_device *dev, struct iw_request_info *info, |
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union iwreq_data *wrqu, char *extra); |
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/* |
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* This define all the handler that the driver export. |
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* As you need only one per driver type, please use a static const |
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* shared by all driver instances... Same for the members... |
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* This will be linked from net_device in <linux/netdevice.h> |
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*/ |
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struct iw_handler_def { |
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/* Array of handlers for standard ioctls |
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* We will call dev->wireless_handlers->standard[ioctl - SIOCIWFIRST] |
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*/ |
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const iw_handler * standard; |
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/* Number of handlers defined (more precisely, index of the |
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* last defined handler + 1) */ |
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__u16 num_standard; |
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#ifdef CONFIG_WEXT_PRIV |
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__u16 num_private; |
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/* Number of private arg description */ |
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__u16 num_private_args; |
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/* Array of handlers for private ioctls |
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* Will call dev->wireless_handlers->private[ioctl - SIOCIWFIRSTPRIV] |
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*/ |
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const iw_handler * private; |
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/* Arguments of private handler. This one is just a list, so you |
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* can put it in any order you want and should not leave holes... |
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* We will automatically export that to user space... */ |
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const struct iw_priv_args * private_args; |
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#endif |
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/* New location of get_wireless_stats, to de-bloat struct net_device. |
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* The old pointer in struct net_device will be gradually phased |
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* out, and drivers are encouraged to use this one... */ |
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struct iw_statistics* (*get_wireless_stats)(struct net_device *dev); |
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}; |
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/* ---------------------- IOCTL DESCRIPTION ---------------------- */ |
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/* |
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* One of the main goal of the new interface is to deal entirely with |
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* user space/kernel space memory move. |
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* For that, we need to know : |
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* o if iwreq is a pointer or contain the full data |
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* o what is the size of the data to copy |
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* |
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* For private IOCTLs, we use the same rules as used by iwpriv and |
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* defined in struct iw_priv_args. |
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* |
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* For standard IOCTLs, things are quite different and we need to |
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* use the structures below. Actually, this struct is also more |
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* efficient, but that's another story... |
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*/ |
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/* |
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* Describe how a standard IOCTL looks like. |
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*/ |
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struct iw_ioctl_description { |
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__u8 header_type; /* NULL, iw_point or other */ |
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__u8 token_type; /* Future */ |
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__u16 token_size; /* Granularity of payload */ |
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__u16 min_tokens; /* Min acceptable token number */ |
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__u16 max_tokens; /* Max acceptable token number */ |
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__u32 flags; /* Special handling of the request */ |
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}; |
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/* Need to think of short header translation table. Later. */ |
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/* --------------------- ENHANCED SPY SUPPORT --------------------- */ |
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/* |
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* In the old days, the driver was handling spy support all by itself. |
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* Now, the driver can delegate this task to Wireless Extensions. |
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* It needs to include this struct in its private part and use the |
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* standard spy iw_handler. |
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*/ |
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/* |
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* Instance specific spy data, i.e. addresses spied and quality for them. |
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*/ |
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struct iw_spy_data { |
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/* --- Standard spy support --- */ |
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int spy_number; |
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u_char spy_address[IW_MAX_SPY][ETH_ALEN]; |
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struct iw_quality spy_stat[IW_MAX_SPY]; |
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/* --- Enhanced spy support (event) */ |
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struct iw_quality spy_thr_low; /* Low threshold */ |
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struct iw_quality spy_thr_high; /* High threshold */ |
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u_char spy_thr_under[IW_MAX_SPY]; |
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}; |
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/* --------------------- DEVICE WIRELESS DATA --------------------- */ |
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/* |
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* This is all the wireless data specific to a device instance that |
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* is managed by the core of Wireless Extensions or the 802.11 layer. |
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* We only keep pointer to those structures, so that a driver is free |
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* to share them between instances. |
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* This structure should be initialised before registering the device. |
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* Access to this data follow the same rules as any other struct net_device |
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* data (i.e. valid as long as struct net_device exist, same locking rules). |
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*/ |
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/* Forward declaration */ |
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struct libipw_device; |
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/* The struct */ |
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struct iw_public_data { |
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/* Driver enhanced spy support */ |
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struct iw_spy_data * spy_data; |
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/* Legacy structure managed by the ipw2x00-specific IEEE 802.11 layer */ |
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struct libipw_device * libipw; |
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}; |
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/**************************** PROTOTYPES ****************************/ |
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/* |
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* Functions part of the Wireless Extensions (defined in net/core/wireless.c). |
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* Those may be called only within the kernel. |
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*/ |
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/* First : function strictly used inside the kernel */ |
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/* Handle /proc/net/wireless, called in net/code/dev.c */ |
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int dev_get_wireless_info(char *buffer, char **start, off_t offset, int length); |
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/* Second : functions that may be called by driver modules */ |
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/* Send a single event to user space */ |
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void wireless_send_event(struct net_device *dev, unsigned int cmd, |
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union iwreq_data *wrqu, const char *extra); |
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#ifdef CONFIG_WEXT_CORE |
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/* flush all previous wext events - if work is done from netdev notifiers */ |
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void wireless_nlevent_flush(void); |
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#else |
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static inline void wireless_nlevent_flush(void) {} |
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#endif |
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/* We may need a function to send a stream of events to user space. |
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* More on that later... */ |
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/* Standard handler for SIOCSIWSPY */ |
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int iw_handler_set_spy(struct net_device *dev, struct iw_request_info *info, |
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union iwreq_data *wrqu, char *extra); |
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/* Standard handler for SIOCGIWSPY */ |
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int iw_handler_get_spy(struct net_device *dev, struct iw_request_info *info, |
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union iwreq_data *wrqu, char *extra); |
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/* Standard handler for SIOCSIWTHRSPY */ |
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int iw_handler_set_thrspy(struct net_device *dev, struct iw_request_info *info, |
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union iwreq_data *wrqu, char *extra); |
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/* Standard handler for SIOCGIWTHRSPY */ |
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int iw_handler_get_thrspy(struct net_device *dev, struct iw_request_info *info, |
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union iwreq_data *wrqu, char *extra); |
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/* Driver call to update spy records */ |
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void wireless_spy_update(struct net_device *dev, unsigned char *address, |
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struct iw_quality *wstats); |
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/************************* INLINE FUNTIONS *************************/ |
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/* |
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* Function that are so simple that it's more efficient inlining them |
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*/ |
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static inline int iwe_stream_lcp_len(struct iw_request_info *info) |
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{ |
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#ifdef CONFIG_COMPAT |
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if (info->flags & IW_REQUEST_FLAG_COMPAT) |
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return IW_EV_COMPAT_LCP_LEN; |
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#endif |
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return IW_EV_LCP_LEN; |
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} |
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static inline int iwe_stream_point_len(struct iw_request_info *info) |
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{ |
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#ifdef CONFIG_COMPAT |
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if (info->flags & IW_REQUEST_FLAG_COMPAT) |
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return IW_EV_COMPAT_POINT_LEN; |
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#endif |
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return IW_EV_POINT_LEN; |
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} |
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static inline int iwe_stream_event_len_adjust(struct iw_request_info *info, |
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int event_len) |
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{ |
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#ifdef CONFIG_COMPAT |
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if (info->flags & IW_REQUEST_FLAG_COMPAT) { |
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event_len -= IW_EV_LCP_LEN; |
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event_len += IW_EV_COMPAT_LCP_LEN; |
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} |
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#endif |
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return event_len; |
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} |
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/*------------------------------------------------------------------*/ |
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/* |
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* Wrapper to add an Wireless Event to a stream of events. |
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*/ |
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char *iwe_stream_add_event(struct iw_request_info *info, char *stream, |
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char *ends, struct iw_event *iwe, int event_len); |
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static inline char * |
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iwe_stream_add_event_check(struct iw_request_info *info, char *stream, |
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char *ends, struct iw_event *iwe, int event_len) |
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{ |
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char *res = iwe_stream_add_event(info, stream, ends, iwe, event_len); |
|
|
|
if (res == stream) |
|
return ERR_PTR(-E2BIG); |
|
return res; |
|
} |
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|
|
/*------------------------------------------------------------------*/ |
|
/* |
|
* 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 */
|
|
|