1 /* 2 * This file define the new driver API for Wireless Extensions 3 * 4 * Version : 7 18.3.05 5 * 6 * Authors : Jean Tourrilhes - HPL - <jt@hpl.hp.com> 7 * Copyright (c) 2001-2006 Jean Tourrilhes, All Rights Reserved. 8 */ 9 10 #ifndef _IW_HANDLER_H 11 #define _IW_HANDLER_H 12 13 /************************** DOCUMENTATION **************************/ 14 /* 15 * Initial driver API (1996 -> onward) : 16 * ----------------------------------- 17 * The initial API just sends the IOCTL request received from user space 18 * to the driver (via the driver ioctl handler). The driver has to 19 * handle all the rest... 20 * 21 * The initial API also defines a specific handler in struct net_device 22 * to handle wireless statistics. 23 * 24 * The initial APIs served us well and has proven a reasonably good design. 25 * However, there is a few shortcommings : 26 * o No events, everything is a request to the driver. 27 * o Large ioctl function in driver with gigantic switch statement 28 * (i.e. spaghetti code). 29 * o Driver has to mess up with copy_to/from_user, and in many cases 30 * does it unproperly. Common mistakes are : 31 * * buffer overflows (no checks or off by one checks) 32 * * call copy_to/from_user with irq disabled 33 * o The user space interface is tied to ioctl because of the use 34 * copy_to/from_user. 35 * 36 * New driver API (2002 -> onward) : 37 * ------------------------------- 38 * The new driver API is just a bunch of standard functions (handlers), 39 * each handling a specific Wireless Extension. The driver just export 40 * the list of handler it supports, and those will be called apropriately. 41 * 42 * I tried to keep the main advantage of the previous API (simplicity, 43 * efficiency and light weight), and also I provide a good dose of backward 44 * compatibility (most structures are the same, driver can use both API 45 * simultaneously, ...). 46 * Hopefully, I've also addressed the shortcomming of the initial API. 47 * 48 * The advantage of the new API are : 49 * o Handling of Extensions in driver broken in small contained functions 50 * o Tighter checks of ioctl before calling the driver 51 * o Flexible commit strategy (at least, the start of it) 52 * o Backward compatibility (can be mixed with old API) 53 * o Driver doesn't have to worry about memory and user-space issues 54 * The last point is important for the following reasons : 55 * o You are now able to call the new driver API from any API you 56 * want (including from within other parts of the kernel). 57 * o Common mistakes are avoided (buffer overflow, user space copy 58 * with irq disabled and so on). 59 * 60 * The Drawback of the new API are : 61 * o bloat (especially kernel) 62 * o need to migrate existing drivers to new API 63 * My initial testing shows that the new API adds around 3kB to the kernel 64 * and save between 0 and 5kB from a typical driver. 65 * Also, as all structures and data types are unchanged, the migration is 66 * quite straightforward (but tedious). 67 * 68 * --- 69 * 70 * The new driver API is defined below in this file. User space should 71 * not be aware of what's happening down there... 72 * 73 * A new kernel wrapper is in charge of validating the IOCTLs and calling 74 * the appropriate driver handler. This is implemented in : 75 * # net/core/wireless.c 76 * 77 * The driver export the list of handlers in : 78 * # include/linux/netdevice.h (one place) 79 * 80 * The new driver API is available for WIRELESS_EXT >= 13. 81 * Good luck with migration to the new API ;-) 82 */ 83 84 /* ---------------------- THE IMPLEMENTATION ---------------------- */ 85 /* 86 * Some of the choice I've made are pretty controversials. Defining an 87 * API is very much weighting compromises. This goes into some of the 88 * details and the thinking behind the implementation. 89 * 90 * Implementation goals : 91 * -------------------- 92 * The implementation goals were as follow : 93 * o Obvious : you should not need a PhD to understand what's happening, 94 * the benefit is easier maintainance. 95 * o Flexible : it should accommodate a wide variety of driver 96 * implementations and be as flexible as the old API. 97 * o Lean : it should be efficient memory wise to minimise the impact 98 * on kernel footprint. 99 * o Transparent to user space : the large number of user space 100 * applications that use Wireless Extensions should not need 101 * any modifications. 102 * 103 * Array of functions versus Struct of functions 104 * --------------------------------------------- 105 * 1) Having an array of functions allow the kernel code to access the 106 * handler in a single lookup, which is much more efficient (think hash 107 * table here). 108 * 2) The only drawback is that driver writer may put their handler in 109 * the wrong slot. This is trivial to test (I set the frequency, the 110 * bitrate changes). Once the handler is in the proper slot, it will be 111 * there forever, because the array is only extended at the end. 112 * 3) Backward/forward compatibility : adding new handler just require 113 * extending the array, so you can put newer driver in older kernel 114 * without having to patch the kernel code (and vice versa). 115 * 116 * All handler are of the same generic type 117 * ---------------------------------------- 118 * That's a feature !!! 119 * 1) Having a generic handler allow to have generic code, which is more 120 * efficient. If each of the handler was individually typed I would need 121 * to add a big switch in the kernel (== more bloat). This solution is 122 * more scalable, adding new Wireless Extensions doesn't add new code. 123 * 2) You can use the same handler in different slots of the array. For 124 * hardware, it may be more efficient or logical to handle multiple 125 * Wireless Extensions with a single function, and the API allow you to 126 * do that. (An example would be a single record on the card to control 127 * both bitrate and frequency, the handler would read the old record, 128 * modify it according to info->cmd and rewrite it). 129 * 130 * Functions prototype uses union iwreq_data 131 * ----------------------------------------- 132 * Some would have prefered functions defined this way : 133 * static int mydriver_ioctl_setrate(struct net_device *dev, 134 * long rate, int auto) 135 * 1) The kernel code doesn't "validate" the content of iwreq_data, and 136 * can't do it (different hardware may have different notion of what a 137 * valid frequency is), so we don't pretend that we do it. 138 * 2) The above form is not extendable. If I want to add a flag (for 139 * example to distinguish setting max rate and basic rate), I would 140 * break the prototype. Using iwreq_data is more flexible. 141 * 3) Also, the above form is not generic (see above). 142 * 4) I don't expect driver developper using the wrong field of the 143 * union (Doh !), so static typechecking doesn't add much value. 144 * 5) Lastly, you can skip the union by doing : 145 * static int mydriver_ioctl_setrate(struct net_device *dev, 146 * struct iw_request_info *info, 147 * struct iw_param *rrq, 148 * char *extra) 149 * And then adding the handler in the array like this : 150 * (iw_handler) mydriver_ioctl_setrate, // SIOCSIWRATE 151 * 152 * Using functions and not a registry 153 * ---------------------------------- 154 * Another implementation option would have been for every instance to 155 * define a registry (a struct containing all the Wireless Extensions) 156 * and only have a function to commit the registry to the hardware. 157 * 1) This approach can be emulated by the current code, but not 158 * vice versa. 159 * 2) Some drivers don't keep any configuration in the driver, for them 160 * adding such a registry would be a significant bloat. 161 * 3) The code to translate from Wireless Extension to native format is 162 * needed anyway, so it would not reduce significantely the amount of code. 163 * 4) The current approach only selectively translate Wireless Extensions 164 * to native format and only selectively set, whereas the registry approach 165 * would require to translate all WE and set all parameters for any single 166 * change. 167 * 5) For many Wireless Extensions, the GET operation return the current 168 * dynamic value, not the value that was set. 169 * 170 * This header is <net/iw_handler.h> 171 * --------------------------------- 172 * 1) This header is kernel space only and should not be exported to 173 * user space. Headers in "include/linux/" are exported, headers in 174 * "include/net/" are not. 175 * 176 * Mixed 32/64 bit issues 177 * ---------------------- 178 * The Wireless Extensions are designed to be 64 bit clean, by using only 179 * datatypes with explicit storage size. 180 * There are some issues related to kernel and user space using different 181 * memory model, and in particular 64bit kernel with 32bit user space. 182 * The problem is related to struct iw_point, that contains a pointer 183 * that *may* need to be translated. 184 * This is quite messy. The new API doesn't solve this problem (it can't), 185 * but is a step in the right direction : 186 * 1) Meta data about each ioctl is easily available, so we know what type 187 * of translation is needed. 188 * 2) The move of data between kernel and user space is only done in a single 189 * place in the kernel, so adding specific hooks in there is possible. 190 * 3) In the long term, it allows to move away from using ioctl as the 191 * user space API. 192 * 193 * So many comments and so few code 194 * -------------------------------- 195 * That's a feature. Comments won't bloat the resulting kernel binary. 196 */ 197 198 /***************************** INCLUDES *****************************/ 199 200 #include <linux/wireless.h> /* IOCTL user space API */ 201 #include <linux/if_ether.h> 202 203 /***************************** VERSION *****************************/ 204 /* 205 * This constant is used to know which version of the driver API is 206 * available. Hopefully, this will be pretty stable and no changes 207 * will be needed... 208 * I just plan to increment with each new version. 209 */ 210 #define IW_HANDLER_VERSION 7 211 212 /* 213 * Changes : 214 * 215 * V2 to V3 216 * -------- 217 * - Move event definition in <linux/wireless.h> 218 * - Add Wireless Event support : 219 * o wireless_send_event() prototype 220 * o iwe_stream_add_event/point() inline functions 221 * V3 to V4 222 * -------- 223 * - Reshuffle IW_HEADER_TYPE_XXX to map IW_PRIV_TYPE_XXX changes 224 * 225 * V4 to V5 226 * -------- 227 * - Add new spy support : struct iw_spy_data & prototypes 228 * 229 * V5 to V6 230 * -------- 231 * - Change the way we get to spy_data method for added safety 232 * - Remove spy #ifdef, they are always on -> cleaner code 233 * - Add IW_DESCR_FLAG_NOMAX flag for very large requests 234 * - Start migrating get_wireless_stats to struct iw_handler_def 235 * 236 * V6 to V7 237 * -------- 238 * - Add struct ieee80211_device pointer in struct iw_public_data 239 * - Remove (struct iw_point *)->pointer from events and streams 240 * - Remove spy_offset from struct iw_handler_def 241 * - Add "check" version of event macros for ieee802.11 stack 242 */ 243 244 /**************************** CONSTANTS ****************************/ 245 246 /* Enhanced spy support available */ 247 #define IW_WIRELESS_SPY 248 #define IW_WIRELESS_THRSPY 249 250 /* Special error message for the driver to indicate that we 251 * should do a commit after return from the iw_handler */ 252 #define EIWCOMMIT EINPROGRESS 253 254 /* Flags available in struct iw_request_info */ 255 #define IW_REQUEST_FLAG_NONE 0x0000 /* No flag so far */ 256 257 /* Type of headers we know about (basically union iwreq_data) */ 258 #define IW_HEADER_TYPE_NULL 0 /* Not available */ 259 #define IW_HEADER_TYPE_CHAR 2 /* char [IFNAMSIZ] */ 260 #define IW_HEADER_TYPE_UINT 4 /* __u32 */ 261 #define IW_HEADER_TYPE_FREQ 5 /* struct iw_freq */ 262 #define IW_HEADER_TYPE_ADDR 6 /* struct sockaddr */ 263 #define IW_HEADER_TYPE_POINT 8 /* struct iw_point */ 264 #define IW_HEADER_TYPE_PARAM 9 /* struct iw_param */ 265 #define IW_HEADER_TYPE_QUAL 10 /* struct iw_quality */ 266 267 /* Handling flags */ 268 /* Most are not implemented. I just use them as a reminder of some 269 * cool features we might need one day ;-) */ 270 #define IW_DESCR_FLAG_NONE 0x0000 /* Obvious */ 271 /* Wrapper level flags */ 272 #define IW_DESCR_FLAG_DUMP 0x0001 /* Not part of the dump command */ 273 #define IW_DESCR_FLAG_EVENT 0x0002 /* Generate an event on SET */ 274 #define IW_DESCR_FLAG_RESTRICT 0x0004 /* GET : request is ROOT only */ 275 /* SET : Omit payload from generated iwevent */ 276 #define IW_DESCR_FLAG_NOMAX 0x0008 /* GET : no limit on request size */ 277 /* Driver level flags */ 278 #define IW_DESCR_FLAG_WAIT 0x0100 /* Wait for driver event */ 279 280 /****************************** TYPES ******************************/ 281 282 /* ----------------------- WIRELESS HANDLER ----------------------- */ 283 /* 284 * A wireless handler is just a standard function, that looks like the 285 * ioctl handler. 286 * We also define there how a handler list look like... As the Wireless 287 * Extension space is quite dense, we use a simple array, which is faster 288 * (that's the perfect hash table ;-). 289 */ 290 291 /* 292 * Meta data about the request passed to the iw_handler. 293 * Most handlers can safely ignore what's in there. 294 * The 'cmd' field might come handy if you want to use the same handler 295 * for multiple command... 296 * This struct is also my long term insurance. I can add new fields here 297 * without breaking the prototype of iw_handler... 298 */ 299 struct iw_request_info 300 { 301 __u16 cmd; /* Wireless Extension command */ 302 __u16 flags; /* More to come ;-) */ 303 }; 304 305 struct net_device; 306 307 /* 308 * This is how a function handling a Wireless Extension should look 309 * like (both get and set, standard and private). 310 */ 311 typedef int (*iw_handler)(struct net_device *dev, struct iw_request_info *info, 312 union iwreq_data *wrqu, char *extra); 313 314 /* 315 * This define all the handler that the driver export. 316 * As you need only one per driver type, please use a static const 317 * shared by all driver instances... Same for the members... 318 * This will be linked from net_device in <linux/netdevice.h> 319 */ 320 struct iw_handler_def 321 { 322 /* Number of handlers defined (more precisely, index of the 323 * last defined handler + 1) */ 324 __u16 num_standard; 325 __u16 num_private; 326 /* Number of private arg description */ 327 __u16 num_private_args; 328 329 /* Array of handlers for standard ioctls 330 * We will call dev->wireless_handlers->standard[ioctl - SIOCSIWCOMMIT] 331 */ 332 const iw_handler * standard; 333 334 /* Array of handlers for private ioctls 335 * Will call dev->wireless_handlers->private[ioctl - SIOCIWFIRSTPRIV] 336 */ 337 const iw_handler * private; 338 339 /* Arguments of private handler. This one is just a list, so you 340 * can put it in any order you want and should not leave holes... 341 * We will automatically export that to user space... */ 342 const struct iw_priv_args * private_args; 343 344 /* New location of get_wireless_stats, to de-bloat struct net_device. 345 * The old pointer in struct net_device will be gradually phased 346 * out, and drivers are encouraged to use this one... */ 347 struct iw_statistics* (*get_wireless_stats)(struct net_device *dev); 348 }; 349 350 /* ---------------------- IOCTL DESCRIPTION ---------------------- */ 351 /* 352 * One of the main goal of the new interface is to deal entirely with 353 * user space/kernel space memory move. 354 * For that, we need to know : 355 * o if iwreq is a pointer or contain the full data 356 * o what is the size of the data to copy 357 * 358 * For private IOCTLs, we use the same rules as used by iwpriv and 359 * defined in struct iw_priv_args. 360 * 361 * For standard IOCTLs, things are quite different and we need to 362 * use the stuctures below. Actually, this struct is also more 363 * efficient, but that's another story... 364 */ 365 366 /* 367 * Describe how a standard IOCTL looks like. 368 */ 369 struct iw_ioctl_description 370 { 371 __u8 header_type; /* NULL, iw_point or other */ 372 __u8 token_type; /* Future */ 373 __u16 token_size; /* Granularity of payload */ 374 __u16 min_tokens; /* Min acceptable token number */ 375 __u16 max_tokens; /* Max acceptable token number */ 376 __u32 flags; /* Special handling of the request */ 377 }; 378 379 /* Need to think of short header translation table. Later. */ 380 381 /* --------------------- ENHANCED SPY SUPPORT --------------------- */ 382 /* 383 * In the old days, the driver was handling spy support all by itself. 384 * Now, the driver can delegate this task to Wireless Extensions. 385 * It needs to include this struct in its private part and use the 386 * standard spy iw_handler. 387 */ 388 389 /* 390 * Instance specific spy data, i.e. addresses spied and quality for them. 391 */ 392 struct iw_spy_data 393 { 394 /* --- Standard spy support --- */ 395 int spy_number; 396 u_char spy_address[IW_MAX_SPY][ETH_ALEN]; 397 struct iw_quality spy_stat[IW_MAX_SPY]; 398 /* --- Enhanced spy support (event) */ 399 struct iw_quality spy_thr_low; /* Low threshold */ 400 struct iw_quality spy_thr_high; /* High threshold */ 401 u_char spy_thr_under[IW_MAX_SPY]; 402 }; 403 404 /* --------------------- DEVICE WIRELESS DATA --------------------- */ 405 /* 406 * This is all the wireless data specific to a device instance that 407 * is managed by the core of Wireless Extensions or the 802.11 layer. 408 * We only keep pointer to those structures, so that a driver is free 409 * to share them between instances. 410 * This structure should be initialised before registering the device. 411 * Access to this data follow the same rules as any other struct net_device 412 * data (i.e. valid as long as struct net_device exist, same locking rules). 413 */ 414 /* Forward declaration */ 415 struct ieee80211_device; 416 /* The struct */ 417 struct iw_public_data { 418 /* Driver enhanced spy support */ 419 struct iw_spy_data * spy_data; 420 /* Structure managed by the in-kernel IEEE 802.11 layer */ 421 struct ieee80211_device * ieee80211; 422 }; 423 424 /**************************** PROTOTYPES ****************************/ 425 /* 426 * Functions part of the Wireless Extensions (defined in net/core/wireless.c). 427 * Those may be called only within the kernel. 428 */ 429 430 /* First : function strictly used inside the kernel */ 431 432 /* Handle /proc/net/wireless, called in net/code/dev.c */ 433 extern int dev_get_wireless_info(char * buffer, char **start, off_t offset, 434 int length); 435 436 /* Handle IOCTLs, called in net/core/dev.c */ 437 extern int wireless_process_ioctl(struct ifreq *ifr, unsigned int cmd); 438 439 /* Handle RtNetlink requests, called in net/core/rtnetlink.c */ 440 extern int wireless_rtnetlink_set(struct net_device * dev, 441 char * data, 442 int len); 443 extern int wireless_rtnetlink_get(struct net_device * dev, 444 char * data, 445 int len, 446 char ** p_buf, 447 int * p_len); 448 449 /* Second : functions that may be called by driver modules */ 450 451 /* Send a single event to user space */ 452 extern void wireless_send_event(struct net_device * dev, 453 unsigned int cmd, 454 union iwreq_data * wrqu, 455 char * extra); 456 457 /* We may need a function to send a stream of events to user space. 458 * More on that later... */ 459 460 /* Standard handler for SIOCSIWSPY */ 461 extern int iw_handler_set_spy(struct net_device * dev, 462 struct iw_request_info * info, 463 union iwreq_data * wrqu, 464 char * extra); 465 /* Standard handler for SIOCGIWSPY */ 466 extern int iw_handler_get_spy(struct net_device * dev, 467 struct iw_request_info * info, 468 union iwreq_data * wrqu, 469 char * extra); 470 /* Standard handler for SIOCSIWTHRSPY */ 471 extern int iw_handler_set_thrspy(struct net_device * dev, 472 struct iw_request_info *info, 473 union iwreq_data * wrqu, 474 char * extra); 475 /* Standard handler for SIOCGIWTHRSPY */ 476 extern int iw_handler_get_thrspy(struct net_device * dev, 477 struct iw_request_info *info, 478 union iwreq_data * wrqu, 479 char * extra); 480 /* Driver call to update spy records */ 481 extern void wireless_spy_update(struct net_device * dev, 482 unsigned char * address, 483 struct iw_quality * wstats); 484 485 /************************* INLINE FUNTIONS *************************/ 486 /* 487 * Function that are so simple that it's more efficient inlining them 488 */ 489 490 /*------------------------------------------------------------------*/ 491 /* 492 * Wrapper to add an Wireless Event to a stream of events. 493 */ 494 static inline char * 495 iwe_stream_add_event(char * stream, /* Stream of events */ 496 char * ends, /* End of stream */ 497 struct iw_event *iwe, /* Payload */ 498 int event_len) /* Real size of payload */ 499 { 500 /* Check if it's possible */ 501 if(likely((stream + event_len) < ends)) { 502 iwe->len = event_len; 503 memcpy(stream, (char *) iwe, event_len); 504 stream += event_len; 505 } 506 return stream; 507 } 508 509 /*------------------------------------------------------------------*/ 510 /* 511 * Wrapper to add an short Wireless Event containing a pointer to a 512 * stream of events. 513 */ 514 static inline char * 515 iwe_stream_add_point(char * stream, /* Stream of events */ 516 char * ends, /* End of stream */ 517 struct iw_event *iwe, /* Payload length + flags */ 518 char * extra) /* More payload */ 519 { 520 int event_len = IW_EV_POINT_LEN + iwe->u.data.length; 521 /* Check if it's possible */ 522 if(likely((stream + event_len) < ends)) { 523 iwe->len = event_len; 524 memcpy(stream, (char *) iwe, IW_EV_LCP_LEN); 525 memcpy(stream + IW_EV_LCP_LEN, 526 ((char *) iwe) + IW_EV_LCP_LEN + IW_EV_POINT_OFF, 527 IW_EV_POINT_LEN - IW_EV_LCP_LEN); 528 memcpy(stream + IW_EV_POINT_LEN, extra, iwe->u.data.length); 529 stream += event_len; 530 } 531 return stream; 532 } 533 534 /*------------------------------------------------------------------*/ 535 /* 536 * Wrapper to add a value to a Wireless Event in a stream of events. 537 * Be careful, this one is tricky to use properly : 538 * At the first run, you need to have (value = event + IW_EV_LCP_LEN). 539 */ 540 static inline char * 541 iwe_stream_add_value(char * event, /* Event in the stream */ 542 char * value, /* Value in event */ 543 char * ends, /* End of stream */ 544 struct iw_event *iwe, /* Payload */ 545 int event_len) /* Real size of payload */ 546 { 547 /* Don't duplicate LCP */ 548 event_len -= IW_EV_LCP_LEN; 549 550 /* Check if it's possible */ 551 if(likely((value + event_len) < ends)) { 552 /* Add new value */ 553 memcpy(value, (char *) iwe + IW_EV_LCP_LEN, event_len); 554 value += event_len; 555 /* Patch LCP */ 556 iwe->len = value - event; 557 memcpy(event, (char *) iwe, IW_EV_LCP_LEN); 558 } 559 return value; 560 } 561 562 /*------------------------------------------------------------------*/ 563 /* 564 * Wrapper to add an Wireless Event to a stream of events. 565 * Same as above, with explicit error check... 566 */ 567 static inline char * 568 iwe_stream_check_add_event(char * stream, /* Stream of events */ 569 char * ends, /* End of stream */ 570 struct iw_event *iwe, /* Payload */ 571 int event_len, /* Size of payload */ 572 int * perr) /* Error report */ 573 { 574 /* Check if it's possible, set error if not */ 575 if(likely((stream + event_len) < ends)) { 576 iwe->len = event_len; 577 memcpy(stream, (char *) iwe, event_len); 578 stream += event_len; 579 } else 580 *perr = -E2BIG; 581 return stream; 582 } 583 584 /*------------------------------------------------------------------*/ 585 /* 586 * Wrapper to add an short Wireless Event containing a pointer to a 587 * stream of events. 588 * Same as above, with explicit error check... 589 */ 590 static inline char * 591 iwe_stream_check_add_point(char * stream, /* Stream of events */ 592 char * ends, /* End of stream */ 593 struct iw_event *iwe, /* Payload length + flags */ 594 char * extra, /* More payload */ 595 int * perr) /* Error report */ 596 { 597 int event_len = IW_EV_POINT_LEN + iwe->u.data.length; 598 /* Check if it's possible */ 599 if(likely((stream + event_len) < ends)) { 600 iwe->len = event_len; 601 memcpy(stream, (char *) iwe, IW_EV_LCP_LEN); 602 memcpy(stream + IW_EV_LCP_LEN, 603 ((char *) iwe) + IW_EV_LCP_LEN + IW_EV_POINT_OFF, 604 IW_EV_POINT_LEN - IW_EV_LCP_LEN); 605 memcpy(stream + IW_EV_POINT_LEN, extra, iwe->u.data.length); 606 stream += event_len; 607 } else 608 *perr = -E2BIG; 609 return stream; 610 } 611 612 /*------------------------------------------------------------------*/ 613 /* 614 * Wrapper to add a value to a Wireless Event in a stream of events. 615 * Be careful, this one is tricky to use properly : 616 * At the first run, you need to have (value = event + IW_EV_LCP_LEN). 617 * Same as above, with explicit error check... 618 */ 619 static inline char * 620 iwe_stream_check_add_value(char * event, /* Event in the stream */ 621 char * value, /* Value in event */ 622 char * ends, /* End of stream */ 623 struct iw_event *iwe, /* Payload */ 624 int event_len, /* Size of payload */ 625 int * perr) /* Error report */ 626 { 627 /* Don't duplicate LCP */ 628 event_len -= IW_EV_LCP_LEN; 629 630 /* Check if it's possible */ 631 if(likely((value + event_len) < ends)) { 632 /* Add new value */ 633 memcpy(value, (char *) iwe + IW_EV_LCP_LEN, event_len); 634 value += event_len; 635 /* Patch LCP */ 636 iwe->len = value - event; 637 memcpy(event, (char *) iwe, IW_EV_LCP_LEN); 638 } else 639 *perr = -E2BIG; 640 return value; 641 } 642 643 #endif /* _IW_HANDLER_H */ 644