xref: /dragonfly/sys/sys/dmsg.h (revision 7d3e9a5b)
1 /*
2  * Copyright (c) 2011-2014 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@dragonflybsd.org>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifndef _SYS_DMSG_H_
36 #define _SYS_DMSG_H_
37 
38 #ifndef _SYS_TYPES_H_
39 #include <sys/types.h>
40 #endif
41 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
42 #ifndef _SYS_TREE_H_
43 #include <sys/tree.h>
44 #endif
45 #ifndef _SYS_THREAD_H_
46 #include <sys/thread.h>
47 #endif
48 #endif
49 #ifndef _SYS_UUID_H_
50 #include <sys/uuid.h>
51 #endif
52 
53 /*
54  * Mesh network protocol structures.
55  *
56  *				CONN PROTOCOL
57  *
58  * The mesh is constructed via point-to-point streaming links with varying
59  * levels of interconnectedness, forming a graph.  Leafs of the graph are
60  * typically kernel devices (xdisk) or VFSs (HAMMER2).  Internal nodes are
61  * usually (user level) hammer2 service demons.
62  *
63  * Upon connecting and after authentication, a LNK_CONN transaction is opened
64  * to configure the link.  The SPAN protocol is then typically run over the
65  * open LNK_CONN transaction.
66  *
67  * Terminating the LNK_CONN transaction terminates everything running over it
68  * (typically open LNK_SPAN transactions), which in turn terminates everything
69  * running over the LNK_SPANs.
70  *
71  *				SPAN PROTOCOL
72  *
73  * The SPAN protocol runs over an open LNK_CONN transaction and is used to
74  * advertise any number of services.  For example, each PFS under a HAMMER2
75  * mount will be advertised as an open LNK_SPAN transaction.
76  *
77  * Any network node on the graph running multiple connections is capable
78  * of relaying LNK_SPANs from any connection to any other connection.  This
79  * is typically done by the user-level hammer2 service demon, and typically
80  * not done by kernel devices or VFSs (though these entities must be able
81  * to manage multiple LNK_SPANs since they might advertise or need to talk
82  * to multiple services).
83  *
84  * Relaying is not necessarily trivial as it requires internal nodes to
85  * track two open transactions (on the two iocom interfaces) and translate
86  * the msgid and circuit.  In addition, the relay may have to track multiple
87  * SPANs from the same iocom or from multiple iocoms which represent the same
88  * end-point and must select the best end-point, must send notifications when
89  * a better path is available, and must allow (when connectivity is still
90  * present) any existing, open, stacked sub-transactions to complete before
91  * terminating the less efficient SPAN.
92  *
93  * Relaying is optional.  It is perfectly acceptable for the hammer2 service
94  * to plug a received socket descriptor directly into the appropriate kernel
95  * device driver.
96  *
97  *			       STACKED TRANSACTIONS
98  *
99  * Message transactions can be stacked.  That is, you can initiate a DMSG
100  * transaction relative to another open transaction.  sub-transactions can
101  * be initiate without waiting for the parent transaction to complete its
102  * handshake.
103  *
104  * This is done by entering the open transaction's msgid as the circuit field
105  * in the new transaction (typically by populating msg->parent).  The
106  * transaction tracking structure will be referenced and will track the
107  * sub-transaction.  Note that msgids must still be unique on an
108  * iocom-by-iocom basis.
109  *
110  * Messages can race closing circuits.  When a circuit is lost,
111  * messages are simulated to delete any sub-transactions.
112  *
113  *			    MESSAGE TRANSACTIONAL STATES
114  *
115  * Message transactions are handled by the CREATE, DELETE, REPLY, ABORT, and
116  * CREPLY flags.  Message state is typically recorded at the end points and
117  * will be maintained (preventing reuse of the transaction id) until a DELETE
118  * is both sent and received.
119  *
120  * One-way messages such as those used for debug commands are not recorded
121  * and do not require any transactional state.  These are sent without
122  * the CREATE, DELETE, or ABORT flags set.  ABORT is not supported for
123  * one-off messages.  The REPLY bit can be used to distinguish between
124  * command and status if desired.
125  *
126  * Transactional messages are messages which require a reply to be
127  * returned.  These messages can also consist of multiple message elements
128  * for the command or reply or both (or neither).  The command message
129  * sequence sets CREATE on the first message and DELETE on the last message.
130  * A single message command sets both (CREATE|DELETE).  The reply message
131  * sequence works the same way but of course also sets the REPLY bit.
132  *
133  * Tansactional messages can be aborted by sending a message element
134  * with the ABORT flag set.  This flag can be combined with either or both
135  * the CREATE and DELETE flags.  When combined with the CREATE flag the
136  * command is treated as non-blocking but still executes.  Whem combined
137  * with the DELETE flag no additional message elements are required.
138  *
139  * Transactions are terminated by sending a message with DELETE set.
140  * Transactions must be CREATEd and DELETEd in both directions.  If a
141  * transaction is governing stacked sub-transactions the sub-transactions
142  * are automatically terminated before the governing transaction is terminated.
143  * Terminates are handled by simulating a received DELETE and expecting the
144  * normal function callback and state machine to (ultimately) issue a
145  * terminating (DELETE) response.
146  *
147  * Transactions can operate in full-duplex as both sides are fully open
148  * (i.e. CREATE sent, CREATE|REPLY returned, DELETE not sent by anyone).
149  * Additional commands can be initiated from either side of the transaction.
150  *
151  * ABORT SPECIAL CASE - Mid-stream aborts.  A mid-stream abort can be sent
152  * when supported by the sender by sending an ABORT message with neither
153  * CREATE or DELETE set.  This effectively turns the message into a
154  * non-blocking message (but depending on what is being represented can also
155  * cut short prior data elements in the stream).
156  *
157  * ABORT SPECIAL CASE - Abort-after-DELETE.  Transactional messages have to be
158  * abortable if the stream/pipe/whatever is lost.  In this situation any
159  * forwarding relay needs to unconditionally abort commands and replies that
160  * are still active.  This is done by sending an ABORT|DELETE even in
161  * situations where a DELETE has already been sent in that direction.  This
162  * is done, for example, when links are in a half-closed state.  In this
163  * situation it is possible for the abort request to race a transition to the
164  * fully closed state.  ABORT|DELETE messages which race the fully closed
165  * state are expected to be discarded by the other end.
166  *
167  * --
168  *
169  * All base and extended message headers are 64-byte aligned, and all
170  * transports must support extended message headers up to DMSG_HDR_MAX.
171  * Currently we allow extended message headers up to 2048 bytes.  Note
172  * that the extended header size is encoded in the 'cmd' field of the header.
173  *
174  * Any in-band data is padded to a 64-byte alignment and placed directly
175  * after the extended header (after the higher-level cmd/rep structure).
176  * The actual unaligned size of the in-band data is encoded in the aux_bytes
177  * field in this case.  Maximum data sizes are negotiated during registration.
178  *
179  * Auxillary data can be in-band or out-of-band.  In-band data sets aux_descr
180  * equal to 0.  Any out-of-band data must be negotiated by the SPAN protocol.
181  *
182  * Auxillary data, whether in-band or out-of-band, must be at-least 64-byte
183  * aligned.  The aux_bytes field contains the actual byte-granular length
184  * and not the aligned length.  The crc is against the aligned length (so
185  * a faster crc algorithm can be used, theoretically).
186  *
187  * hdr_crc is calculated over the entire, ALIGNED extended header.  For
188  * the purposes of calculating the crc, the hdr_crc field is 0.  That is,
189  * if calculating the crc in HW a 32-bit '0' must be inserted in place of
190  * the hdr_crc field when reading the entire header and compared at the
191  * end (but the actual hdr_crc must be left intact in memory).  A simple
192  * counter to replace the field going into the CRC generator does the job
193  * in HW.  The CRC endian is based on the magic number field and may have
194  * to be byte-swapped, too (which is also easy to do in HW).
195  *
196  * aux_crc is calculated over the entire, ALIGNED auxillary data.
197  *
198  *			SHARED MEMORY IMPLEMENTATIONS
199  *
200  * Shared-memory implementations typically use a pipe to transmit the extended
201  * message header and shared memory to store any auxilary data.  Auxillary
202  * data in one-way (non-transactional) messages is typically required to be
203  * inline.  CRCs are still recommended and required at the beginning, but
204  * may be negotiated away later.
205  */
206 
207 #define DMSG_TERMINATE_STRING(ary)	\
208 	do { (ary)[sizeof(ary) - 1] = 0; } while (0)
209 
210 /*
211  * dmsg_hdr must be 64 bytes
212  */
213 struct dmsg_hdr {
214 	uint16_t	magic;		/* 00 sanity, synchro, endian */
215 	uint16_t	reserved02;	/* 02 */
216 	uint32_t	salt;		/* 04 random salt helps w/crypto */
217 
218 	uint64_t	msgid;		/* 08 message transaction id */
219 	uint64_t	circuit;	/* 10 circuit id or 0	*/
220 	uint64_t	link_verifier;	/* 18 link verifier */
221 
222 	uint32_t	cmd;		/* 20 flags | cmd | hdr_size / ALIGN */
223 	uint32_t	aux_crc;	/* 24 auxillary data crc */
224 	uint32_t	aux_bytes;	/* 28 auxillary data length (bytes) */
225 	uint32_t	error;		/* 2C error code or 0 */
226 	uint64_t	aux_descr;	/* 30 negotiated OOB data descr */
227 	uint32_t	reserved38;	/* 38 */
228 	uint32_t	hdr_crc;	/* 3C (aligned) extended header crc */
229 };
230 
231 typedef struct dmsg_hdr dmsg_hdr_t;
232 
233 #define DMSG_HDR_MAGIC		0x4832
234 #define DMSG_HDR_MAGIC_REV	0x3248
235 #define DMSG_HDR_CRCOFF		offsetof(dmsg_hdr_t, salt)
236 #define DMSG_HDR_CRCBYTES	(sizeof(dmsg_hdr_t) - DMSG_HDR_CRCOFF)
237 
238 /*
239  * Administrative protocol limits.
240  *
241  * NOTE: A dmsg header must completely fit in the (fifo) buffer, but
242  *	 dmsg aux data does not have to completely fit.  The dmsg
243  *	 structure allows headers up to 255*64 = 16320 bytes.  There
244  *	 is no real limit on the aux_data other than what we deem
245  *	 reasonable and defenseable (i.e. not run processes or the
246  *	 kernel out of memory).  But it should be able to handle at
247  *	 least MAXPHYS bytes which is typically 128KB or 256KB.
248  */
249 #define DMSG_HDR_MAX		2048		/* <= 8192 */
250 #define DMSG_AUX_MAX		(1024*1024)	/* <= 1MB */
251 #define DMSG_BUF_SIZE		(DMSG_HDR_MAX * 4)
252 #define DMSG_BUF_MASK		(DMSG_BUF_SIZE - 1)
253 
254 /*
255  * The message (cmd) field also encodes various flags and the total size
256  * of the message header.  This allows the protocol processors to validate
257  * persistency and structural settings for every command simply by
258  * switch()ing on the (cmd) field.
259  */
260 #define DMSGF_CREATE		0x80000000U	/* msg start */
261 #define DMSGF_DELETE		0x40000000U	/* msg end */
262 #define DMSGF_REPLY		0x20000000U	/* reply path */
263 #define DMSGF_ABORT		0x10000000U	/* abort req */
264 #define DMSGF_REVTRANS		0x08000000U	/* opposite direction msgid */
265 #define DMSGF_REVCIRC		0x04000000U	/* opposite direction circuit */
266 #define DMSGF_FLAG1		0x02000000U
267 #define DMSGF_FLAG0		0x01000000U
268 
269 #define DMSGF_FLAGS		0xFF000000U	/* all flags */
270 #define DMSGF_PROTOS		0x00F00000U	/* all protos */
271 #define DMSGF_CMDS		0x000FFF00U	/* all cmds */
272 #define DMSGF_SIZE		0x000000FFU	/* N*32 */
273 
274 /*
275  * XXX Future, flag that an in-line (not part of a CREATE/DELETE) command
276  *     expects some sort of acknowledgement.  Allows protocol mismatches to
277  *     be detected.
278  */
279 #define DMSGF_CMDF_EXPECT_ACK	0x00080000U	/* in-line command no-ack */
280 
281 #define DMSGF_CMDSWMASK		(DMSGF_CMDS |	\
282 					 DMSGF_SIZE |	\
283 					 DMSGF_PROTOS |	\
284 					 DMSGF_REPLY)
285 
286 #define DMSGF_BASECMDMASK	(DMSGF_CMDS |	\
287 					 DMSGF_SIZE |	\
288 					 DMSGF_PROTOS)
289 
290 #define DMSGF_TRANSMASK		(DMSGF_CMDS |	\
291 					 DMSGF_SIZE |	\
292 					 DMSGF_PROTOS |	\
293 					 DMSGF_REPLY |	\
294 					 DMSGF_CREATE |	\
295 					 DMSGF_DELETE)
296 
297 #define DMSGF_BASEFLAGS		(DMSGF_CREATE | DMSGF_DELETE | DMSGF_REPLY)
298 
299 #define DMSG_PROTO_LNK		0x00000000U
300 #define DMSG_PROTO_DBG		0x00100000U
301 #define DMSG_PROTO_HM2		0x00200000U
302 #define DMSG_PROTO_XX3		0x00300000U
303 #define DMSG_PROTO_XX4		0x00400000U
304 #define DMSG_PROTO_BLK		0x00500000U
305 #define DMSG_PROTO_VOP		0x00600000U
306 
307 /*
308  * Message command constructors, sans flags
309  */
310 #define DMSG_ALIGN		64
311 #define DMSG_ALIGNMASK		(DMSG_ALIGN - 1)
312 #define DMSG_DOALIGN(bytes)	(((bytes) + DMSG_ALIGNMASK) &		\
313 				 ~DMSG_ALIGNMASK)
314 
315 #define DMSG_HDR_ENCODE(elm)	(((uint32_t)sizeof(struct elm) +	\
316 				  DMSG_ALIGNMASK) /			\
317 				 DMSG_ALIGN)
318 
319 #define DMSG_LNK(cmd, elm)	(DMSG_PROTO_LNK |			\
320 					 ((cmd) << 8) | 		\
321 					 DMSG_HDR_ENCODE(elm))
322 
323 #define DMSG_DBG(cmd, elm)	(DMSG_PROTO_DBG |			\
324 					 ((cmd) << 8) | 		\
325 					 DMSG_HDR_ENCODE(elm))
326 
327 #define DMSG_HM2(cmd, elm)	(DMSG_PROTO_HM2 |			\
328 					 ((cmd) << 8) | 		\
329 					 DMSG_HDR_ENCODE(elm))
330 
331 #define DMSG_BLK(cmd, elm)	(DMSG_PROTO_BLK |			\
332 					 ((cmd) << 8) | 		\
333 					 DMSG_HDR_ENCODE(elm))
334 
335 #define DMSG_VOP(cmd, elm)	(DMSG_PROTO_VOP |			\
336 					 ((cmd) << 8) | 		\
337 					 DMSG_HDR_ENCODE(elm))
338 
339 /*
340  * Link layer ops basically talk to just the other side of a direct
341  * connection.
342  *
343  * LNK_PAD	- One-way message on circuit 0, ignored by target.  Used to
344  *		  pad message buffers on shared-memory transports.  Not
345  *		  typically used with TCP.
346  *
347  * LNK_PING	- One-way message on circuit-0, keep-alive, run by both sides
348  *		  typically 1/sec on idle link, link is lost after 10 seconds
349  *		  of inactivity.
350  *
351  * LNK_AUTH	- Authenticate the connection, negotiate administrative
352  *		  rights & encryption, protocol class, etc.  Only PAD and
353  *		  AUTH messages (not even PING) are accepted until
354  *		  authentication is complete.  This message also identifies
355  *		  the host.
356  *
357  * LNK_CONN	- Enable the SPAN protocol on circuit-0, possibly also
358  *		  installing a PFS filter (by cluster id, unique id, and/or
359  *		  wildcarded name).
360  *
361  * LNK_SPAN	- A SPAN transaction typically on iocom->state0 enables
362  *		  messages to be relayed to/from a particular cluster node.
363  *		  SPANs are received, sorted, aggregated, filtered, and
364  *		  retransmitted back out across all applicable connections.
365  *
366  *		  The leaf protocol also uses this to make a PFS available
367  *		  to the cluster (e.g. on-mount).
368  */
369 #define DMSG_LNK_PAD		DMSG_LNK(0x000, dmsg_hdr)
370 #define DMSG_LNK_PING		DMSG_LNK(0x001, dmsg_hdr)
371 #define DMSG_LNK_AUTH		DMSG_LNK(0x010, dmsg_lnk_auth)
372 #define DMSG_LNK_CONN		DMSG_LNK(0x011, dmsg_lnk_conn)
373 #define DMSG_LNK_SPAN		DMSG_LNK(0x012, dmsg_lnk_span)
374 #define DMSG_LNK_ERROR		DMSG_LNK(0xFFF, dmsg_hdr)
375 
376 /*
377  * Reserved command codes for third party subsystems.  Structure size is
378  * not known here so do not try to construct the full DMSG_LNK_ define.
379  */
380 #define DMSG_LNK_CMD_HAMMER2_VOLCONF	0x20
381 
382 #define DMSG_LABEL_SIZE		128	/* fixed at 128, do not change */
383 
384 /*
385  * LNK_AUTH - Authentication (often omitted)
386  */
387 struct dmsg_lnk_auth {
388 	dmsg_hdr_t	head;
389 	char		dummy[64];
390 };
391 
392 /*
393  * LNK_CONN - Register connection info for SPAN protocol
394  *	      (transaction, left open, iocom->state0 only).
395  *
396  * LNK_CONN identifies a streaming connection into the cluster.
397  *
398  * peer_mask serves to filter the SPANs we receive by peer_type.  A cluster
399  * controller typically sets this to (uint64_t)-1, indicating that it wants
400  * everything.  A block devfs interface might set it to 1 << DMSG_PEER_DISK,
401  * and a hammer2 mount might set it to 1 << DMSG_PEER_HAMMER2.
402  *
403  * media_iud allows multiple (e.g. HAMMER2) connections belonging to the same
404  * media to transmit duplicative LNK_VOLCONF updates without causing confusion
405  * in the cluster controller.
406  *
407  * pfs_clid, pfs_fsid, pfs_type, and label are peer-specific and must be
408  * left empty (zero-fill) if not supported by a particular peer.
409  */
410 struct dmsg_lnk_conn {
411 	dmsg_hdr_t	head;
412 	uuid_t		media_id;	/* media configuration id */
413 	uuid_t		peer_id;	/* unique peer uuid */
414 	uuid_t		reserved01;
415 	uint64_t	peer_mask;	/* PEER mask for SPAN filtering */
416 	uint8_t		peer_type;	/* see DMSG_PEER_xxx */
417 	uint8_t		reserved02;
418 	uint16_t	proto_version;	/* high level protocol support */
419 	uint32_t	status;		/* status flags */
420 	uint32_t	rnss;		/* node's generated rnss */
421 	uint8_t		reserved03[8];
422 	uint32_t	reserved04[14];
423 	char		peer_label[DMSG_LABEL_SIZE]; /* peer identity string */
424 };
425 
426 typedef struct dmsg_lnk_conn dmsg_lnk_conn_t;
427 
428 /*
429  * PEER types 0-63 are defined here.  There is a limit of 64 types due to
430  * the width of peer_mask.
431  *
432  * PFS types depend on the peer type.  sys/dmsg.h only defines the default.
433  * peer-specific headers define PFS types for any given peer.
434  */
435 #define DMSG_PEER_NONE			0
436 #define DMSG_PEER_ROUTER		1	/* server: cluster controller */
437 #define DMSG_PEER_BLOCK			2	/* server: block devices */
438 #define DMSG_PEER_HAMMER2		3	/* server: h2 mounted volume */
439 #define DMSG_PEER_CLIENT		63	/* a client connection */
440 #define DMSG_PEER_MAX			64
441 
442 #define DMSG_PFSTYPE_DEFAULT		0
443 #define DMSG_PFSTYPE_MASK		0x0F
444 
445 /*
446  * Structures embedded in LNK_SPAN
447  */
448 struct dmsg_media_block {
449 	uint64_t	bytes;		/* media size in bytes */
450 	uint32_t	blksize;	/* media block size */
451 	uint32_t	reserved01;
452 };
453 
454 typedef struct dmsg_media_block dmsg_media_block_t;
455 
456 /*
457  * LNK_SPAN - Initiate or relay a SPAN
458  *	      (transaction, left open, typically only on iocom->state0)
459  *
460  * This message registers an end-point with the other end of the connection,
461  * telling the other end who we are and what we can provide or intend to
462  * consume.  Multiple registrations can be maintained as open transactions
463  * with each one specifying a unique end-point.
464  *
465  * Registrations are sent from {source}=S {1...n} to {target}=0 and maintained
466  * as open transactions.  Registrations are also received and maintains as
467  * open transactions, creating a matrix of linkid's.
468  *
469  * While these transactions are open additional transactions can be executed
470  * between any two linkid's {source}=S (registrations we sent) to {target}=T
471  * (registrations we received).
472  *
473  * Closure of any registration transaction will automatically abort any open
474  * transactions using the related linkids.  Closure can be initiated
475  * voluntarily from either side with either end issuing a DELETE, or they
476  * can be ABORTed.
477  *
478  * Status updates are performed via the open transaction.
479  *
480  * --
481  *
482  * A registration identifies a node and its various PFS parameters including
483  * the PFS_TYPE.  For example, a diskless HAMMER2 client typically identifies
484  * itself as PFSTYPE_CLIENT.
485  *
486  * Any node may serve as a cluster controller, aggregating and passing
487  * on received registrations, but end-points do not have to implement this
488  * ability.  Most end-points typically implement a single client-style or
489  * server-style PFS_TYPE and rendezvous at a cluster controller.
490  *
491  * The cluster controller does not aggregate/pass-on all received
492  * registrations.  It typically filters what gets passed on based on what it
493  * receives, passing on only the best candidates.
494  *
495  * If a symmetric spanning tree is desired additional candidates whos
496  * {dist, rnss} fields match the last best candidate must also be propagated.
497  * This feature is not currently enabled.
498  *
499  * STATUS UPDATES: Status updates use the same structure but typically
500  *		   only contain incremental changes to e.g. pfs_type, with
501  *		   a text description sent as out-of-band data.
502  */
503 struct dmsg_lnk_span {
504 	dmsg_hdr_t	head;
505 	uuid_t		peer_id;
506 	uuid_t		pfs_id;		/* unique pfs id */
507 	uint8_t		pfs_type;	/* PFS type */
508 	uint8_t		peer_type;	/* PEER type */
509 	uint16_t	proto_version;	/* high level protocol support */
510 	uint32_t	status;		/* status flags */
511 	uint8_t		reserved02[8];
512 	uint32_t	dist;		/* span distance */
513 	uint32_t	rnss;		/* random number sub-sort */
514 	union {
515 		uint32_t	reserved03[14];
516 		dmsg_media_block_t block;
517 	} media;
518 
519 	/*
520 	 * NOTE: for PEER_HAMMER2 cl_label is typically empty and fs_label
521 	 *	 is the superroot directory name.
522 	 *
523 	 *	 for PEER_BLOCK cl_label is typically host/device and
524 	 *	 fs_label is typically the serial number string.
525 	 */
526 	char		peer_label[DMSG_LABEL_SIZE];	/* peer label */
527 	char		pfs_label[DMSG_LABEL_SIZE];	/* PFS label */
528 };
529 
530 typedef struct dmsg_lnk_span dmsg_lnk_span_t;
531 
532 #define DMSG_SPAN_PROTO_1	1
533 
534 /*
535  * Debug layer ops operate on any link
536  *
537  * SHELL	- Persist stream, access the debug shell on the target
538  *		  registration.  Multiple shells can be operational.
539  */
540 #define DMSG_DBG_SHELL		DMSG_DBG(0x001, dmsg_dbg_shell)
541 
542 struct dmsg_dbg_shell {
543 	dmsg_hdr_t	head;
544 };
545 typedef struct dmsg_dbg_shell dmsg_dbg_shell_t;
546 
547 /*
548  * Hammer2 layer ops (low-level chain manipulation used by cluster code)
549  *
550  * HM2_OPENPFS	- Attach a PFS
551  * HM2_FLUSHPFS - Flush a PFS
552  *
553  * HM2_LOOKUP	- Lookup chain (parent-relative transaction)
554  *		  (can request multiple chains)
555  * HM2_NEXT	- Lookup next chain (parent-relative transaction)
556  *		  (can request multiple chains)
557  * HM2_LOCK	- [Re]lock a chain (chain-relative) (non-recursive)
558  * HM2_UNLOCK	- Unlock a chain (chain-relative) (non-recursive)
559  * HM2_RESIZE	- Resize a chain (chain-relative)
560  * HM2_MODIFY	- Modify a chain (chain-relative)
561  * HM2_CREATE	- Create a chain (parent-relative)
562  * HM2_DUPLICATE- Duplicate a chain (target-parent-relative)
563  * HM2_DELDUP	- Delete-Duplicate a chain (chain-relative)
564  * HM2_DELETE	- Delete a chain (chain-relative)
565  * HM2_SNAPSHOT	- Create a snapshot (snapshot-root-relative, w/clid override)
566  */
567 #define DMSG_HM2_OPENPFS	DMSG_HM2(0x001, dmsg_hm2_openpfs)
568 
569 /*
570  * DMSG_PROTO_BLK Protocol
571  *
572  * BLK_OPEN	- Open device.  This transaction must be left open for the
573  *		  duration and the returned keyid passed in all associated
574  *		  BLK commands.  Multiple OPENs can be issued within the
575  *		  transaction.
576  *
577  * BLK_CLOSE	- Close device.  This can be used to close one of the opens
578  *		  within a BLK_OPEN transaction.  It may NOT initiate a
579  *		  transaction.  Note that a termination of the transaction
580  *		  (e.g. with LNK_ERROR or BLK_ERROR) closes all active OPENs
581  *		  for that transaction.  XXX not well defined atm.
582  *
583  * BLK_READ	- Strategy read.  Not typically streaming.
584  *
585  * BLK_WRITE	- Strategy write.  Not typically streaming.
586  *
587  * BLK_FLUSH	- Strategy flush.  Not typically streaming.
588  *
589  * BLK_FREEBLKS	- Strategy freeblks.  Not typically streaming.
590  */
591 #define DMSG_BLK_OPEN		DMSG_BLK(0x001, dmsg_blk_open)
592 #define DMSG_BLK_CLOSE		DMSG_BLK(0x002, dmsg_blk_open)
593 #define DMSG_BLK_READ		DMSG_BLK(0x003, dmsg_blk_read)
594 #define DMSG_BLK_WRITE		DMSG_BLK(0x004, dmsg_blk_write)
595 #define DMSG_BLK_FLUSH		DMSG_BLK(0x005, dmsg_blk_flush)
596 #define DMSG_BLK_FREEBLKS	DMSG_BLK(0x006, dmsg_blk_freeblks)
597 #define DMSG_BLK_ERROR		DMSG_BLK(0xFFF, dmsg_blk_error)
598 
599 struct dmsg_blk_open {
600 	dmsg_hdr_t	head;
601 	uint32_t	modes;
602 	uint32_t	reserved01;
603 };
604 
605 #define DMSG_BLKOPEN_RD		0x0001
606 #define DMSG_BLKOPEN_WR		0x0002
607 
608 /*
609  * DMSG_LNK_ERROR is returned for simple results,
610  * DMSG_BLK_ERROR is returned for extended results.
611  */
612 struct dmsg_blk_error {
613 	dmsg_hdr_t	head;
614 	uint64_t	keyid;
615 	uint32_t	resid;
616 	uint32_t	reserved02;
617 	char		buf[64];
618 };
619 
620 struct dmsg_blk_read {
621 	dmsg_hdr_t	head;
622 	uint64_t	keyid;
623 	uint64_t	offset;
624 	uint32_t	bytes;
625 	uint32_t	flags;
626 	uint32_t	reserved01;
627 	uint32_t	reserved02;
628 };
629 
630 struct dmsg_blk_write {
631 	dmsg_hdr_t	head;
632 	uint64_t	keyid;
633 	uint64_t	offset;
634 	uint32_t	bytes;
635 	uint32_t	flags;
636 	uint32_t	reserved01;
637 	uint32_t	reserved02;
638 };
639 
640 struct dmsg_blk_flush {
641 	dmsg_hdr_t	head;
642 	uint64_t	keyid;
643 	uint64_t	offset;
644 	uint32_t	bytes;
645 	uint32_t	flags;
646 	uint32_t	reserved01;
647 	uint32_t	reserved02;
648 };
649 
650 struct dmsg_blk_freeblks {
651 	dmsg_hdr_t	head;
652 	uint64_t	keyid;
653 	uint64_t	offset;
654 	uint32_t	bytes;
655 	uint32_t	flags;
656 	uint32_t	reserved01;
657 	uint32_t	reserved02;
658 };
659 
660 typedef struct dmsg_blk_open		dmsg_blk_open_t;
661 typedef struct dmsg_blk_read		dmsg_blk_read_t;
662 typedef struct dmsg_blk_write		dmsg_blk_write_t;
663 typedef struct dmsg_blk_flush		dmsg_blk_flush_t;
664 typedef struct dmsg_blk_freeblks	dmsg_blk_freeblks_t;
665 typedef struct dmsg_blk_error		dmsg_blk_error_t;
666 
667 /*
668  * NOTE!!!! ALL EXTENDED HEADER STRUCTURES MUST BE 64-BYTE ALIGNED!!!
669  *
670  * General message errors
671  *
672  *	0x00 - 0x1F	Local iocomm errors
673  *	0x20 - 0x2F	Global errors
674  */
675 #define DMSG_ERR_NOSUPP		0x20
676 #define DMSG_ERR_LOSTLINK	0x21
677 #define DMSG_ERR_IO		0x22	/* generic */
678 #define DMSG_ERR_PARAM		0x23	/* generic */
679 #define DMSG_ERR_CANTCIRC	0x24	/* (typically means lost span) */
680 
681 union dmsg_any {
682 	char			buf[DMSG_HDR_MAX];
683 	dmsg_hdr_t		head;
684 
685 	dmsg_lnk_conn_t		lnk_conn;
686 	dmsg_lnk_span_t		lnk_span;
687 
688 	dmsg_blk_open_t		blk_open;
689 	dmsg_blk_error_t	blk_error;
690 	dmsg_blk_read_t		blk_read;
691 	dmsg_blk_write_t	blk_write;
692 	dmsg_blk_flush_t	blk_flush;
693 	dmsg_blk_freeblks_t	blk_freeblks;
694 };
695 
696 typedef union dmsg_any dmsg_any_t;
697 
698 /*
699  * Kernel iocom structures and prototypes for kern/kern_dmsg.c
700  */
701 #if defined(_KERNEL) || defined(_KERNEL_STRUCTURES)
702 
703 struct hammer2_mount;
704 struct xa_softc;
705 struct kdmsg_iocom;
706 struct kdmsg_state;
707 struct kdmsg_msg;
708 struct kdmsg_data;
709 
710 /*
711  * msg_ctl flags (atomic)
712  */
713 #define KDMSG_CLUSTERCTL_UNUSED01	0x00000001
714 #define KDMSG_CLUSTERCTL_KILLRX		0x00000002 /* staged helper exit */
715 #define KDMSG_CLUSTERCTL_KILLTX		0x00000004 /* staged helper exit */
716 #define KDMSG_CLUSTERCTL_SLEEPING	0x00000008 /* interlocked w/msglk */
717 
718 /*
719  * Transactional state structure, representing an open transaction.  The
720  * transaction might represent a cache state (and thus have a chain
721  * association), or a VOP op, LNK_SPAN, or other things.
722  *
723  * NOTE: A non-empty subq represents one ref.
724  *	 If we are inserted on a parent's subq, that's one ref (SUBINSERTED).
725  *	 If we are inserted on a RB tree, that's one ref (RBINSERTED).
726  *	 msg->state represents a ref.
727  *	 Other code references may hold refs.
728  *
729  * NOTE: The parent association stays intact as long as a state has a
730  *	 non-empty subq.  Otherwise simulated failures might not be able
731  *	 to reach the children.
732  */
733 TAILQ_HEAD(kdmsg_state_list, kdmsg_state);
734 
735 struct kdmsg_state {
736 	RB_ENTRY(kdmsg_state) rbnode;		/* indexed by msgid */
737 	struct kdmsg_state	*scan;		/* scan check */
738 	struct kdmsg_state_list	subq;		/* active stacked states */
739 	TAILQ_ENTRY(kdmsg_state) entry;		/* on parent subq */
740 	TAILQ_ENTRY(kdmsg_state) user_entry;	/* available to devices */
741 	struct kdmsg_iocom *iocom;
742 	struct kdmsg_state *parent;
743 	int		refs;			/* refs */
744 	uint32_t	icmd;			/* record cmd creating state */
745 	uint32_t	txcmd;			/* mostly for CMDF flags */
746 	uint32_t	rxcmd;			/* mostly for CMDF flags */
747 	uint64_t	msgid;			/* {parent,msgid} uniq */
748 	int		flags;
749 	int		error;
750 	void		*chain;			/* (caller's state) */
751 	int (*func)(struct kdmsg_state *, struct kdmsg_msg *);
752 	union {
753 		void *any;
754 		struct hammer2_mount *hmp;
755 		struct xa_softc *xa_sc;
756 	} any;
757 };
758 
759 #define KDMSG_STATE_SUBINSERTED	0x0001
760 #define KDMSG_STATE_DYNAMIC	0x0002
761 #define KDMSG_STATE_UNUSED0004	0x0004
762 #define KDMSG_STATE_ABORTING	0x0008		/* avoids recursive abort */
763 #define KDMSG_STATE_OPPOSITE	0x0010		/* opposite direction */
764 #define KDMSG_STATE_DYING	0x0020		/* atomic recursive circ fail */
765 #define KDMSG_STATE_INTERLOCK	0x0040
766 #define KDMSG_STATE_RBINSERTED	0x0080
767 #define KDMSG_STATE_SIGNAL	0x0400
768 #define KDMSG_STATE_NEW		0x0800		/* defer abort processing */
769 
770 struct kdmsg_msg {
771 	TAILQ_ENTRY(kdmsg_msg) qentry;		/* serialized queue */
772 	struct kdmsg_state *state;
773 	size_t		hdr_size;
774 	size_t		aux_size;
775 	char		*aux_data;
776 	uint32_t	flags;
777 	uint32_t	tcmd;			/* outer transaction cmd */
778 	dmsg_any_t	any;			/* variable sized */
779 };
780 
781 struct kdmsg_data {
782 	char		*aux_data;
783 	size_t		aux_size;
784 	struct kdmsg_iocom *iocom;
785 };
786 
787 #define KDMSG_FLAG_AUXALLOC	0x0001
788 
789 typedef struct kdmsg_link kdmsg_link_t;
790 typedef struct kdmsg_state kdmsg_state_t;
791 typedef struct kdmsg_msg kdmsg_msg_t;
792 typedef struct kdmsg_data kdmsg_data_t;
793 
794 struct kdmsg_state_tree;
795 int kdmsg_state_cmp(kdmsg_state_t *state1, kdmsg_state_t *state2);
796 RB_HEAD(kdmsg_state_tree, kdmsg_state);
797 RB_PROTOTYPE(kdmsg_state_tree, kdmsg_state, rbnode, kdmsg_state_cmp);
798 
799 struct file;			/* forward decl */
800 struct malloc_type;
801 
802 /*
803  * Structure embedded in e.g. mount, master control structure for
804  * DMSG stream handling.
805  */
806 struct kdmsg_iocom {
807 	struct malloc_type	*mmsg;
808 	struct file		*msg_fp;	/* cluster pipe->userland */
809 	thread_t		msgrd_td;	/* cluster thread */
810 	thread_t		msgwr_td;	/* cluster thread */
811 	int			msg_ctl;	/* wakeup flags */
812 	int			msg_seq;	/* cluster msg sequence id */
813 	uint32_t		flags;
814 	struct lock		msglk;		/* lockmgr lock */
815 	TAILQ_HEAD(, kdmsg_msg) msgq;		/* transmit queue */
816 	void			*handle;
817 	void			(*auto_callback)(kdmsg_msg_t *);
818 	int			(*rcvmsg)(kdmsg_msg_t *);
819 	void			(*exit_func)(struct kdmsg_iocom *);
820 	struct kdmsg_state	state0;		/* root state for stacking */
821 	struct kdmsg_state	*conn_state;	/* active LNK_CONN state */
822 	struct kdmsg_state	*freerd_state;	/* allocation cache */
823 	struct kdmsg_state	*freewr_state;	/* allocation cache */
824 	struct kdmsg_state_tree staterd_tree;	/* active messages */
825 	struct kdmsg_state_tree statewr_tree;	/* active messages */
826 	dmsg_lnk_conn_t		auto_lnk_conn;
827 	dmsg_lnk_span_t		auto_lnk_span;
828 };
829 
830 typedef struct kdmsg_iocom	kdmsg_iocom_t;
831 
832 #define KDMSG_IOCOMF_AUTOCONN	0x0001	/* handle RX/TX LNK_CONN */
833 #define KDMSG_IOCOMF_AUTORXSPAN	0x0002	/* handle RX LNK_SPAN */
834 #define KDMSG_IOCOMF_AUTOTXSPAN	0x0008	/* handle TX LNK_SPAN */
835 #define KDMSG_IOCOMF_EXITNOACC	0x8000	/* cannot accept writes */
836 
837 #define KDMSG_IOCOMF_AUTOANY	(KDMSG_IOCOMF_AUTOCONN |	\
838 				 KDMSG_IOCOMF_AUTORXSPAN |	\
839 				 KDMSG_IOCOMF_AUTOTXSPAN)
840 
841 #endif	/* _KERNEL || _KERNEL_STRUCTURES */
842 
843 #ifdef _KERNEL
844 
845 /*
846  * kern_dmsg.c
847  */
848 void kdmsg_iocom_init(kdmsg_iocom_t *iocom, void *handle, u_int32_t flags,
849 			struct malloc_type *mmsg,
850 			int (*rcvmsg)(kdmsg_msg_t *msg));
851 void kdmsg_iocom_reconnect(kdmsg_iocom_t *iocom, struct file *fp,
852 			const char *subsysname);
853 void kdmsg_iocom_autoinitiate(kdmsg_iocom_t *iocom,
854 			void (*conn_callback)(kdmsg_msg_t *msg));
855 void kdmsg_iocom_uninit(kdmsg_iocom_t *iocom);
856 void kdmsg_drain_msgq(kdmsg_iocom_t *iocom);
857 
858 void kdmsg_msg_free(kdmsg_msg_t *msg);
859 kdmsg_msg_t *kdmsg_msg_alloc(kdmsg_state_t *state, uint32_t cmd,
860 				int (*func)(kdmsg_state_t *, kdmsg_msg_t *),
861 				void *data);
862 void kdmsg_msg_write(kdmsg_msg_t *msg);
863 void kdmsg_msg_reply(kdmsg_msg_t *msg, uint32_t error);
864 void kdmsg_msg_result(kdmsg_msg_t *msg, uint32_t error);
865 void kdmsg_state_reply(kdmsg_state_t *state, uint32_t error);
866 void kdmsg_state_result(kdmsg_state_t *state, uint32_t error);
867 void kdmsg_detach_aux_data(kdmsg_msg_t *msg, kdmsg_data_t *data);
868 void kdmsg_free_aux_data(kdmsg_data_t *data);
869 
870 #endif	/* _KERNEL */
871 
872 #endif	/* !_SYS_DMSG_H_ */
873