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irnet.h
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1 /*
2  * IrNET protocol module : Synchronous PPP over an IrDA socket.
3  *
4  * Jean II - HPL `00 - <[email protected]>
5  *
6  * This file contains definitions and declarations global to the IrNET module,
7  * all grouped in one place...
8  * This file is a *private* header, so other modules don't want to know
9  * what's in there...
10  *
11  * Note : as most part of the Linux kernel, this module is available
12  * under the GNU General Public License (GPL).
13  */
14 
15 #ifndef IRNET_H
16 #define IRNET_H
17 
18 /************************** DOCUMENTATION ***************************/
19 /*
20  * What is IrNET
21  * -------------
22  * IrNET is a protocol allowing to carry TCP/IP traffic between two
23  * IrDA peers in an efficient fashion. It is a thin layer, passing PPP
24  * packets to IrTTP and vice versa. It uses PPP in synchronous mode,
25  * because IrTTP offer a reliable sequenced packet service (as opposed
26  * to a byte stream). In fact, you could see IrNET as carrying TCP/IP
27  * in a IrDA socket, using PPP to provide the glue.
28  *
29  * The main difference with traditional PPP over IrCOMM is that we
30  * avoid the framing and serial emulation which are a performance
31  * bottleneck. It also allows multipoint communications in a sensible
32  * fashion.
33  *
34  * The main difference with IrLAN is that we use PPP for the link
35  * management, which is more standard, interoperable and flexible than
36  * the IrLAN protocol. For example, PPP adds authentication,
37  * encryption, compression, header compression and automated routing
38  * setup. And, as IrNET let PPP do the hard work, the implementation
39  * is much simpler than IrLAN.
40  *
41  * The Linux implementation
42  * ------------------------
43  * IrNET is written on top of the Linux-IrDA stack, and interface with
44  * the generic Linux PPP driver. Because IrNET depend on recent
45  * changes of the PPP driver interface, IrNET will work only with very
46  * recent kernel (2.3.99-pre6 and up).
47  *
48  * The present implementation offer the following features :
49  * o simple user interface using pppd
50  * o efficient implementation (interface directly to PPP and IrTTP)
51  * o addressing (you can specify the name of the IrNET recipient)
52  * o multipoint operation (limited by IrLAP specification)
53  * o information in /proc/net/irda/irnet
54  * o IrNET events on /dev/irnet (for user space daemon)
55  * o IrNET daemon (irnetd) to automatically handle incoming requests
56  * o Windows 2000 compatibility (tested, but need more work)
57  * Currently missing :
58  * o Lot's of testing (that's your job)
59  * o Connection retries (may be too hard to do)
60  * o Check pppd persist mode
61  * o User space daemon (to automatically handle incoming requests)
62  *
63  * The setup is not currently the most easy, but this should get much
64  * better when everything will get integrated...
65  *
66  * Acknowledgements
67  * ----------------
68  * This module is based on :
69  * o The PPP driver (ppp_synctty/ppp_generic) by Paul Mackerras
70  * o The IrLAN protocol (irlan_common/XXX) by Dag Brattli
71  * o The IrSock interface (af_irda) by Dag Brattli
72  * o Some other bits from the kernel and my drivers...
73  * Infinite thanks to those brave souls for providing the infrastructure
74  * upon which IrNET is built.
75  *
76  * Thanks to all my colleagues in HP for helping me. In particular,
77  * thanks to Salil Pradhan and Bill Serra for W2k testing...
78  * Thanks to Luiz Magalhaes for irnetd and much testing...
79  *
80  * Thanks to Alan Cox for answering lot's of my stupid questions, and
81  * to Paul Mackerras answering my questions on how to best integrate
82  * IrNET and pppd.
83  *
84  * Jean II
85  *
86  * Note on some implementations choices...
87  * ------------------------------------
88  * 1) Direct interface vs tty/socket
89  * I could have used a tty interface to hook to ppp and use the full
90  * socket API to connect to IrDA. The code would have been easier to
91  * maintain, and maybe the code would have been smaller...
92  * Instead, we hook directly to ppp_generic and to IrTTP, which make
93  * things more complicated...
94  *
95  * The first reason is flexibility : this allow us to create IrNET
96  * instances on demand (no /dev/ircommX crap) and to allow linkname
97  * specification on pppd command line...
98  *
99  * Second reason is speed optimisation. If you look closely at the
100  * transmit and receive paths, you will notice that they are "super lean"
101  * (that's why they look ugly), with no function calls and as little data
102  * copy and modification as I could...
103  *
104  * 2) irnetd in user space
105  * irnetd is implemented in user space, which is necessary to call pppd.
106  * This also give maximum benefits in term of flexibility and customability,
107  * and allow to offer the event channel, useful for other stuff like debug.
108  *
109  * On the other hand, this require a loose coordination between the
110  * present module and irnetd. One critical area is how incoming request
111  * are handled.
112  * When irnet receive an incoming request, it send an event to irnetd and
113  * drop the incoming IrNET socket.
114  * irnetd start a pppd instance, which create a new IrNET socket. This new
115  * socket is then connected in the originating node to the pppd instance.
116  * At this point, in the originating node, the first socket is closed.
117  *
118  * I admit, this is a bit messy and waste some resources. The alternative
119  * is caching incoming socket, and that's also quite messy and waste
120  * resources.
121  * We also make connection time slower. For example, on a 115 kb/s link it
122  * adds 60ms to the connection time (770 ms). However, this is slower than
123  * the time it takes to fire up pppd on my P133...
124  *
125  *
126  * History :
127  * -------
128  *
129  * v1 - 15.5.00 - Jean II
130  * o Basic IrNET (hook to ppp_generic & IrTTP - incl. multipoint)
131  * o control channel on /dev/irnet (set name/address)
132  * o event channel on /dev/irnet (for user space daemon)
133  *
134  * v2 - 5.6.00 - Jean II
135  * o Enable DROP_NOT_READY to avoid PPP timeouts & other weirdness...
136  * o Add DISCONNECT_TO event and rename DISCONNECT_FROM.
137  * o Set official device number alloaction on /dev/irnet
138  *
139  * v3 - 30.8.00 - Jean II
140  * o Update to latest Linux-IrDA changes :
141  * - queue_t => irda_queue_t
142  * o Update to ppp-2.4.0 :
143  * - move irda_irnet_connect from PPPIOCATTACH to TIOCSETD
144  * o Add EXPIRE event (depend on new IrDA-Linux patch)
145  * o Switch from `hashbin_remove' to `hashbin_remove_this' to fix
146  * a multilink bug... (depend on new IrDA-Linux patch)
147  * o fix a self->daddr to self->raddr in irda_irnet_connect to fix
148  * another multilink bug (darn !)
149  * o Remove LINKNAME_IOCTL cruft
150  *
151  * v3b - 31.8.00 - Jean II
152  * o Dump discovery log at event channel startup
153  *
154  * v4 - 28.9.00 - Jean II
155  * o Fix interaction between poll/select and dump discovery log
156  * o Add IRNET_BLOCKED_LINK event (depend on new IrDA-Linux patch)
157  * o Add IRNET_NOANSWER_FROM event (mostly to help support)
158  * o Release flow control in disconnect_indication
159  * o Block packets while connecting (speed up connections)
160  *
161  * v5 - 11.01.01 - Jean II
162  * o Init self->max_header_size, just in case...
163  * o Set up ap->chan.hdrlen, to get zero copy on tx side working.
164  * o avoid tx->ttp->flow->ppp->tx->... loop, by checking flow state
165  * Thanks to Christian Gennerat for finding this bug !
166  * ---
167  * o Declare the proper MTU/MRU that we can support
168  * (but PPP doesn't read the MTU value :-()
169  * o Declare hashbin HB_NOLOCK instead of HB_LOCAL to avoid
170  * disabling and enabling irq twice
171  *
172  * v6 - 31.05.01 - Jean II
173  * o Print source address in Found, Discovery, Expiry & Request events
174  * o Print requested source address in /proc/net/irnet
175  * o Change control channel input. Allow multiple commands in one line.
176  * o Add saddr command to change ap->rsaddr (and use that in IrDA)
177  * ---
178  * o Make the IrDA connection procedure totally asynchronous.
179  * Heavy rewrite of the IAS query code and the whole connection
180  * procedure. Now, irnet_connect() no longer need to be called from
181  * a process context...
182  * o Enable IrDA connect retries in ppp_irnet_send(). The good thing
183  * is that IrDA connect retries are directly driven by PPP LCP
184  * retries (we retry for each LCP packet), so that everything
185  * is transparently controlled from pppd lcp-max-configure.
186  * o Add ttp_connect flag to prevent rentry on the connect procedure
187  * o Test and fixups to eliminate side effects of retries
188  *
189  * v7 - 22.08.01 - Jean II
190  * o Cleanup : Change "saddr = 0x0" to "saddr = DEV_ADDR_ANY"
191  * o Fix bug in BLOCK_WHEN_CONNECT introduced in v6 : due to the
192  * asynchronous IAS query, self->tsap is NULL when PPP send the
193  * first packet. This was preventing "connect-delay 0" to work.
194  * Change the test in ppp_irnet_send() to self->ttp_connect.
195  *
196  * v8 - 1.11.01 - Jean II
197  * o Tighten the use of self->ttp_connect and self->ttp_open to
198  * prevent various race conditions.
199  * o Avoid leaking discovery log and skb
200  * o Replace "self" with "server" in irnet_connect_indication() to
201  * better detect cut'n'paste error ;-)
202  *
203  * v9 - 29.11.01 - Jean II
204  * o Fix event generation in disconnect indication that I broke in v8
205  * It was always generation "No-Answer" because I was testing ttp_open
206  * just after clearing it. *blush*.
207  * o Use newly created irttp_listen() to fix potential crash when LAP
208  * destroyed before irnet module removed.
209  *
210  * v10 - 4.3.2 - Jean II
211  * o When receiving a disconnect indication, don't reenable the
212  * PPP Tx queue, this will trigger a reconnect. Instead, close
213  * the channel, which will kill pppd...
214  *
215  * v11 - 20.3.02 - Jean II
216  * o Oops ! v10 fix disabled IrNET retries and passive behaviour.
217  * Better fix in irnet_disconnect_indication() :
218  * - if connected, kill pppd via hangup.
219  * - if not connected, reenable ppp Tx, which trigger IrNET retry.
220  *
221  * v12 - 10.4.02 - Jean II
222  * o Fix race condition in irnet_connect_indication().
223  * If the socket was already trying to connect, drop old connection
224  * and use new one only if acting as primary. See comments.
225  *
226  * v13 - 30.5.02 - Jean II
227  * o Update module init code
228  *
229  * v14 - 20.2.03 - Jean II
230  * o Add discovery hint bits in the control channel.
231  * o Remove obsolete MOD_INC/DEC_USE_COUNT in favor of .owner
232  *
233  * v15 - 7.4.03 - Jean II
234  * o Replace spin_lock_irqsave() with spin_lock_bh() so that we can
235  * use ppp_unit_number(). It's probably also better overall...
236  * o Disable call to ppp_unregister_channel(), because we can't do it.
237  */
238 
239 /***************************** INCLUDES *****************************/
240 
241 #include <linux/module.h>
242 
243 #include <linux/kernel.h>
244 #include <linux/skbuff.h>
245 #include <linux/tty.h>
246 #include <linux/proc_fs.h>
247 #include <linux/netdevice.h>
248 #include <linux/miscdevice.h>
249 #include <linux/poll.h>
250 #include <linux/capability.h>
251 #include <linux/ctype.h> /* isspace() */
252 #include <linux/string.h> /* skip_spaces() */
253 #include <asm/uaccess.h>
254 #include <linux/init.h>
255 
256 #include <linux/ppp_defs.h>
257 #include <linux/ppp-ioctl.h>
258 #include <linux/ppp_channel.h>
259 
260 #include <net/irda/irda.h>
261 #include <net/irda/iriap.h>
262 #include <net/irda/irias_object.h>
263 #include <net/irda/irlmp.h>
264 #include <net/irda/irttp.h>
265 #include <net/irda/discovery.h>
266 
267 /***************************** OPTIONS *****************************/
268 /*
269  * Define or undefine to compile or not some optional part of the
270  * IrNET driver...
271  * Note : the present defaults make sense, play with that at your
272  * own risk...
273  */
274 /* IrDA side of the business... */
275 #define DISCOVERY_NOMASK /* To enable W2k compatibility... */
276 #define ADVERTISE_HINT /* Advertise IrLAN hint bit */
277 #define ALLOW_SIMULT_CONNECT /* This seem to work, cross fingers... */
278 #define DISCOVERY_EVENTS /* Query the discovery log to post events */
279 #define INITIAL_DISCOVERY /* Dump current discovery log as events */
280 #undef STREAM_COMPAT /* Not needed - potentially messy */
281 #undef CONNECT_INDIC_KICK /* Might mess IrDA, not needed */
282 #undef FAIL_SEND_DISCONNECT /* Might mess IrDA, not needed */
283 #undef PASS_CONNECT_PACKETS /* Not needed ? Safe */
284 #undef MISSING_PPP_API /* Stuff I wish I could do */
285 
286 /* PPP side of the business */
287 #define BLOCK_WHEN_CONNECT /* Block packets when connecting */
288 #define CONNECT_IN_SEND /* Retry IrDA connection procedure */
289 #undef FLUSH_TO_PPP /* Not sure about this one, let's play safe */
290 #undef SECURE_DEVIRNET /* Bah... */
291 
292 /****************************** DEBUG ******************************/
293 
294 /*
295  * This set of flags enable and disable all the various warning,
296  * error and debug message of this driver.
297  * Each section can be enabled and disabled independently
298  */
299 /* In the PPP part */
300 #define DEBUG_CTRL_TRACE 0 /* Control channel */
301 #define DEBUG_CTRL_INFO 0 /* various info */
302 #define DEBUG_CTRL_ERROR 1 /* problems */
303 #define DEBUG_FS_TRACE 0 /* filesystem callbacks */
304 #define DEBUG_FS_INFO 0 /* various info */
305 #define DEBUG_FS_ERROR 1 /* problems */
306 #define DEBUG_PPP_TRACE 0 /* PPP related functions */
307 #define DEBUG_PPP_INFO 0 /* various info */
308 #define DEBUG_PPP_ERROR 1 /* problems */
309 #define DEBUG_MODULE_TRACE 0 /* module insertion/removal */
310 #define DEBUG_MODULE_ERROR 1 /* problems */
311 
312 /* In the IrDA part */
313 #define DEBUG_IRDA_SR_TRACE 0 /* IRDA subroutines */
314 #define DEBUG_IRDA_SR_INFO 0 /* various info */
315 #define DEBUG_IRDA_SR_ERROR 1 /* problems */
316 #define DEBUG_IRDA_SOCK_TRACE 0 /* IRDA main socket functions */
317 #define DEBUG_IRDA_SOCK_INFO 0 /* various info */
318 #define DEBUG_IRDA_SOCK_ERROR 1 /* problems */
319 #define DEBUG_IRDA_SERV_TRACE 0 /* The IrNET server */
320 #define DEBUG_IRDA_SERV_INFO 0 /* various info */
321 #define DEBUG_IRDA_SERV_ERROR 1 /* problems */
322 #define DEBUG_IRDA_TCB_TRACE 0 /* IRDA IrTTP callbacks */
323 #define DEBUG_IRDA_CB_INFO 0 /* various info */
324 #define DEBUG_IRDA_CB_ERROR 1 /* problems */
325 #define DEBUG_IRDA_OCB_TRACE 0 /* IRDA other callbacks */
326 #define DEBUG_IRDA_OCB_INFO 0 /* various info */
327 #define DEBUG_IRDA_OCB_ERROR 1 /* problems */
328 
329 #define DEBUG_ASSERT 0 /* Verify all assertions */
330 
331 /*
332  * These are the macros we are using to actually print the debug
333  * statements. Don't look at it, it's ugly...
334  *
335  * One of the trick is that, as the DEBUG_XXX are constant, the
336  * compiler will optimise away the if() in all cases.
337  */
338 /* All error messages (will show up in the normal logs) */
339 #define DERROR(dbg, format, args...) \
340  {if(DEBUG_##dbg) \
341  printk(KERN_INFO "irnet: %s(): " format, __func__ , ##args);}
342 
343 /* Normal debug message (will show up in /var/log/debug) */
344 #define DEBUG(dbg, format, args...) \
345  {if(DEBUG_##dbg) \
346  printk(KERN_DEBUG "irnet: %s(): " format, __func__ , ##args);}
347 
348 /* Entering a function (trace) */
349 #define DENTER(dbg, format, args...) \
350  {if(DEBUG_##dbg) \
351  printk(KERN_DEBUG "irnet: -> %s" format, __func__ , ##args);}
352 
353 /* Entering and exiting a function in one go (trace) */
354 #define DPASS(dbg, format, args...) \
355  {if(DEBUG_##dbg) \
356  printk(KERN_DEBUG "irnet: <>%s" format, __func__ , ##args);}
357 
358 /* Exiting a function (trace) */
359 #define DEXIT(dbg, format, args...) \
360  {if(DEBUG_##dbg) \
361  printk(KERN_DEBUG "irnet: <-%s()" format, __func__ , ##args);}
362 
363 /* Exit a function with debug */
364 #define DRETURN(ret, dbg, args...) \
365  {DEXIT(dbg, ": " args);\
366  return ret; }
367 
368 /* Exit a function on failed condition */
369 #define DABORT(cond, ret, dbg, args...) \
370  {if(cond) {\
371  DERROR(dbg, args);\
372  return ret; }}
373 
374 /* Invalid assertion, print out an error and exit... */
375 #define DASSERT(cond, ret, dbg, args...) \
376  {if((DEBUG_ASSERT) && !(cond)) {\
377  DERROR(dbg, "Invalid assertion: " args);\
378  return ret; }}
379 
380 /************************ CONSTANTS & MACROS ************************/
381 
382 /* Paranoia */
383 #define IRNET_MAGIC 0xB00754
384 
385 /* Number of control events in the control channel buffer... */
386 #define IRNET_MAX_EVENTS 8 /* Should be more than enough... */
387 
388 /****************************** TYPES ******************************/
389 
390 /*
391  * This is the main structure where we store all the data pertaining to
392  * one instance of irnet.
393  * Note : in irnet functions, a pointer this structure is usually called
394  * "ap" or "self". If the code is borrowed from the IrDA stack, it tend
395  * to be called "self", and if it is borrowed from the PPP driver it is
396  * "ap". Apart from that, it's exactly the same structure ;-)
397  */
398 typedef struct irnet_socket
399 {
400  /* ------------------- Instance management ------------------- */
401  /* We manage a linked list of IrNET socket instances */
402  irda_queue_t q; /* Must be first - for hasbin */
403  int magic; /* Paranoia */
404 
405  /* --------------------- FileSystem part --------------------- */
406  /* "pppd" interact directly with us on a /dev/ file */
407  struct file * file; /* File descriptor of this instance */
408  /* TTY stuff - to keep "pppd" happy */
409  struct ktermios termios; /* Various tty flags */
410  /* Stuff for the control channel */
411  int event_index; /* Last read in the event log */
412 
413  /* ------------------------- PPP part ------------------------- */
414  /* We interface directly to the ppp_generic driver in the kernel */
415  int ppp_open; /* registered with ppp_generic */
416  struct ppp_channel chan; /* Interface to generic ppp layer */
417 
418  int mru; /* Max size of PPP payload */
419  u32 xaccm[8]; /* Asynchronous character map (just */
420  u32 raccm; /* to please pppd - dummy) */
421  unsigned int flags; /* PPP flags (compression, ...) */
422  unsigned int rbits; /* Unused receive flags ??? */
423  struct work_struct disconnect_work; /* Process context disconnection */
424  /* ------------------------ IrTTP part ------------------------ */
425  /* We create a pseudo "socket" over the IrDA tranport */
426  unsigned long ttp_open; /* Set when IrTTP is ready */
427  unsigned long ttp_connect; /* Set when IrTTP is connecting */
428  struct tsap_cb * tsap; /* IrTTP instance (the connection) */
429 
431  /* IrDA nickname of destination */
432  __u32 rdaddr; /* Requested peer IrDA address */
433  __u32 rsaddr; /* Requested local IrDA address */
434  __u32 daddr; /* actual peer IrDA address */
435  __u32 saddr; /* my local IrDA address */
436  __u8 dtsap_sel; /* Remote TSAP selector */
437  __u8 stsap_sel; /* Local TSAP selector */
438 
439  __u32 max_sdu_size_rx;/* Socket parameters used for IrTTP */
443  LOCAL_FLOW tx_flow; /* State of the Tx path in IrTTP */
444 
445  /* ------------------- IrLMP and IrIAS part ------------------- */
446  /* Used for IrDA Discovery and socket name resolution */
447  void * ckey; /* IrLMP client handle */
448  __u16 mask; /* Hint bits mask (filter discov.)*/
449  int nslots; /* Number of slots for discovery */
450 
451  struct iriap_cb * iriap; /* Used to query remote IAS */
452  int errno; /* status of the IAS query */
453 
454  /* -------------------- Discovery log part -------------------- */
455  /* Used by initial discovery on the control channel
456  * and by irnet_discover_daddr_and_lsap_sel() */
457  struct irda_device_info *discoveries; /* Copy of the discovery log */
458  int disco_index; /* Last read in the discovery log */
459  int disco_number; /* Size of the discovery log */
460 
461  struct mutex lock;
462 
463 } irnet_socket;
464 
465 /*
466  * This is the various event that we will generate on the control channel
467  */
468 typedef enum irnet_event
469 {
470  IRNET_DISCOVER, /* New IrNET node discovered */
471  IRNET_EXPIRE, /* IrNET node expired */
472  IRNET_CONNECT_TO, /* IrNET socket has connected to other node */
473  IRNET_CONNECT_FROM, /* Other node has connected to IrNET socket */
474  IRNET_REQUEST_FROM, /* Non satisfied connection request */
475  IRNET_NOANSWER_FROM, /* Failed connection request */
476  IRNET_BLOCKED_LINK, /* Link (IrLAP) is blocked for > 3s */
477  IRNET_DISCONNECT_FROM, /* IrNET socket has disconnected */
478  IRNET_DISCONNECT_TO /* Closing IrNET socket */
479 } irnet_event;
480 
481 /*
482  * This is the storage for an event and its arguments
483  */
484 typedef struct irnet_log
485 {
487  int unit;
490  char name[NICKNAME_MAX_LEN + 1]; /* 21 + 1 */
491  __u16_host_order hints; /* Discovery hint bits */
492 } irnet_log;
493 
494 /*
495  * This is the storage for all events and related stuff...
496  */
497 typedef struct irnet_ctrl_channel
498 {
499  irnet_log log[IRNET_MAX_EVENTS]; /* Event log */
500  int index; /* Current index in log */
501  spinlock_t spinlock; /* Serialize access to the event log */
502  wait_queue_head_t rwait; /* processes blocked on read (or poll) */
504 
505 /**************************** PROTOTYPES ****************************/
506 /*
507  * Global functions of the IrNET module
508  * Note : we list here also functions called from one file to the other.
509  */
510 
511 /* -------------------------- IRDA PART -------------------------- */
512 extern int
513  irda_irnet_create(irnet_socket *); /* Initialise a IrNET socket */
514 extern int
515  irda_irnet_connect(irnet_socket *); /* Try to connect over IrDA */
516 extern void
517  irda_irnet_destroy(irnet_socket *); /* Teardown a IrNET socket */
518 extern int
519  irda_irnet_init(void); /* Initialise IrDA part of IrNET */
520 extern void
521  irda_irnet_cleanup(void); /* Teardown IrDA part of IrNET */
522 
523 /**************************** VARIABLES ****************************/
524 
525 /* Control channel stuff - allocated in irnet_irda.h */
526 extern struct irnet_ctrl_channel irnet_events;
527 
528 #endif /* IRNET_H */