1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * RDMA Network Block Driver
4  *
5  * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
6  * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
7  * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
8  */
9 #ifndef RNBD_PROTO_H
10 #define RNBD_PROTO_H
11 
12 #include <linux/types.h>
13 #include <linux/blk-mq.h>
14 #include <linux/limits.h>
15 #include <linux/inet.h>
16 #include <linux/in.h>
17 #include <linux/in6.h>
18 #include <rdma/ib.h>
19 
20 #define RNBD_PROTO_VER_MAJOR 2
21 #define RNBD_PROTO_VER_MINOR 0
22 
23 /* The default port number the RTRS server is listening on. */
24 #define RTRS_PORT 1234
25 
26 /**
27  * enum rnbd_msg_types - RNBD message types
28  * @RNBD_MSG_SESS_INFO:	initial session info from client to server
29  * @RNBD_MSG_SESS_INFO_RSP:	initial session info from server to client
30  * @RNBD_MSG_OPEN:		open (map) device request
31  * @RNBD_MSG_OPEN_RSP:		response to an @RNBD_MSG_OPEN
32  * @RNBD_MSG_IO:		block IO request operation
33  * @RNBD_MSG_CLOSE:		close (unmap) device request
34  */
35 enum rnbd_msg_type {
36 	RNBD_MSG_SESS_INFO,
37 	RNBD_MSG_SESS_INFO_RSP,
38 	RNBD_MSG_OPEN,
39 	RNBD_MSG_OPEN_RSP,
40 	RNBD_MSG_IO,
41 	RNBD_MSG_CLOSE,
42 };
43 
44 /**
45  * struct rnbd_msg_hdr - header of RNBD messages
46  * @type:	Message type, valid values see: enum rnbd_msg_types
47  */
48 struct rnbd_msg_hdr {
49 	__le16		type;
50 	__le16		__padding;
51 };
52 
53 /**
54  * We allow to map RO many times and RW only once. We allow to map yet another
55  * time RW, if MIGRATION is provided (second RW export can be required for
56  * example for VM migration)
57  */
58 enum rnbd_access_mode {
59 	RNBD_ACCESS_RO,
60 	RNBD_ACCESS_RW,
61 	RNBD_ACCESS_MIGRATION,
62 };
63 
64 /**
65  * struct rnbd_msg_sess_info - initial session info from client to server
66  * @hdr:		message header
67  * @ver:		RNBD protocol version
68  */
69 struct rnbd_msg_sess_info {
70 	struct rnbd_msg_hdr hdr;
71 	u8		ver;
72 	u8		reserved[31];
73 };
74 
75 /**
76  * struct rnbd_msg_sess_info_rsp - initial session info from server to client
77  * @hdr:		message header
78  * @ver:		RNBD protocol version
79  */
80 struct rnbd_msg_sess_info_rsp {
81 	struct rnbd_msg_hdr hdr;
82 	u8		ver;
83 	u8		reserved[31];
84 };
85 
86 /**
87  * struct rnbd_msg_open - request to open a remote device.
88  * @hdr:		message header
89  * @access_mode:	the mode to open remote device, valid values see:
90  *			enum rnbd_access_mode
91  * @device_name:	device path on remote side
92  */
93 struct rnbd_msg_open {
94 	struct rnbd_msg_hdr hdr;
95 	u8		access_mode;
96 	u8		resv1;
97 	s8		dev_name[NAME_MAX];
98 	u8		reserved[3];
99 };
100 
101 /**
102  * struct rnbd_msg_close - request to close a remote device.
103  * @hdr:	message header
104  * @device_id:	device_id on server side to identify the device
105  */
106 struct rnbd_msg_close {
107 	struct rnbd_msg_hdr hdr;
108 	__le32		device_id;
109 };
110 
111 enum rnbd_cache_policy {
112 	RNBD_FUA = 1 << 0,
113 	RNBD_WRITEBACK = 1 << 1,
114 };
115 
116 /**
117  * struct rnbd_msg_open_rsp - response message to RNBD_MSG_OPEN
118  * @hdr:		message header
119  * @device_id:		device_id on server side to identify the device
120  * @nsectors:		number of sectors in the usual 512b unit
121  * @max_hw_sectors:	max hardware sectors in the usual 512b unit
122  * @max_write_same_sectors: max sectors for WRITE SAME in the 512b unit
123  * @max_discard_sectors: max. sectors that can be discarded at once in 512b
124  * unit.
125  * @discard_granularity: size of the internal discard allocation unit in bytes
126  * @discard_alignment: offset from internal allocation assignment in bytes
127  * @physical_block_size: physical block size device supports in bytes
128  * @logical_block_size: logical block size device supports in bytes
129  * @max_segments:	max segments hardware support in one transfer
130  * @secure_discard:	supports secure discard
131  * @obsolete_rotational: obsolete, not in used.
132  * @cache_policy: 	support write-back caching or FUA?
133  */
134 struct rnbd_msg_open_rsp {
135 	struct rnbd_msg_hdr	hdr;
136 	__le32			device_id;
137 	__le64			nsectors;
138 	__le32			max_hw_sectors;
139 	__le32			max_write_same_sectors;
140 	__le32			max_discard_sectors;
141 	__le32			discard_granularity;
142 	__le32			discard_alignment;
143 	__le16			physical_block_size;
144 	__le16			logical_block_size;
145 	__le16			max_segments;
146 	__le16			secure_discard;
147 	u8			obsolete_rotational;
148 	u8			cache_policy;
149 	u8			reserved[10];
150 };
151 
152 /**
153  * struct rnbd_msg_io - message for I/O read/write
154  * @hdr:	message header
155  * @device_id:	device_id on server side to find the right device
156  * @sector:	bi_sector attribute from struct bio
157  * @rw:		valid values are defined in enum rnbd_io_flags
158  * @bi_size:    number of bytes for I/O read/write
159  * @prio:       priority
160  */
161 struct rnbd_msg_io {
162 	struct rnbd_msg_hdr hdr;
163 	__le32		device_id;
164 	__le64		sector;
165 	__le32		rw;
166 	__le32		bi_size;
167 	__le16		prio;
168 };
169 
170 #define RNBD_OP_BITS  8
171 #define RNBD_OP_MASK  ((1 << RNBD_OP_BITS) - 1)
172 
173 /**
174  * enum rnbd_io_flags - RNBD request types from rq_flag_bits
175  * @RNBD_OP_READ:	     read sectors from the device
176  * @RNBD_OP_WRITE:	     write sectors to the device
177  * @RNBD_OP_FLUSH:	     flush the volatile write cache
178  * @RNBD_OP_DISCARD:        discard sectors
179  * @RNBD_OP_SECURE_ERASE:   securely erase sectors
180  * @RNBD_OP_WRITE_SAME:     write the same sectors many times
181 
182  * @RNBD_F_SYNC:	     request is sync (sync write or read)
183  * @RNBD_F_FUA:             forced unit access
184  */
185 enum rnbd_io_flags {
186 
187 	/* Operations */
188 
189 	RNBD_OP_READ		= 0,
190 	RNBD_OP_WRITE		= 1,
191 	RNBD_OP_FLUSH		= 2,
192 	RNBD_OP_DISCARD	= 3,
193 	RNBD_OP_SECURE_ERASE	= 4,
194 	RNBD_OP_WRITE_SAME	= 5,
195 
196 	RNBD_OP_LAST,
197 
198 	/* Flags */
199 
200 	RNBD_F_SYNC  = 1<<(RNBD_OP_BITS + 0),
201 	RNBD_F_FUA   = 1<<(RNBD_OP_BITS + 1),
202 
203 	RNBD_F_ALL   = (RNBD_F_SYNC | RNBD_F_FUA)
204 
205 };
206 
rnbd_op(u32 flags)207 static inline u32 rnbd_op(u32 flags)
208 {
209 	return flags & RNBD_OP_MASK;
210 }
211 
rnbd_flags(u32 flags)212 static inline u32 rnbd_flags(u32 flags)
213 {
214 	return flags & ~RNBD_OP_MASK;
215 }
216 
rnbd_flags_supported(u32 flags)217 static inline bool rnbd_flags_supported(u32 flags)
218 {
219 	u32 op;
220 
221 	op = rnbd_op(flags);
222 	flags = rnbd_flags(flags);
223 
224 	if (op >= RNBD_OP_LAST)
225 		return false;
226 	if (flags & ~RNBD_F_ALL)
227 		return false;
228 
229 	return true;
230 }
231 
rnbd_to_bio_flags(u32 rnbd_opf)232 static inline u32 rnbd_to_bio_flags(u32 rnbd_opf)
233 {
234 	u32 bio_opf;
235 
236 	switch (rnbd_op(rnbd_opf)) {
237 	case RNBD_OP_READ:
238 		bio_opf = REQ_OP_READ;
239 		break;
240 	case RNBD_OP_WRITE:
241 		bio_opf = REQ_OP_WRITE;
242 		break;
243 	case RNBD_OP_FLUSH:
244 		bio_opf = REQ_OP_FLUSH | REQ_PREFLUSH;
245 		break;
246 	case RNBD_OP_DISCARD:
247 		bio_opf = REQ_OP_DISCARD;
248 		break;
249 	case RNBD_OP_SECURE_ERASE:
250 		bio_opf = REQ_OP_SECURE_ERASE;
251 		break;
252 	default:
253 		WARN(1, "Unknown RNBD type: %d (flags %d)\n",
254 		     rnbd_op(rnbd_opf), rnbd_opf);
255 		bio_opf = 0;
256 	}
257 
258 	if (rnbd_opf & RNBD_F_SYNC)
259 		bio_opf |= REQ_SYNC;
260 
261 	if (rnbd_opf & RNBD_F_FUA)
262 		bio_opf |= REQ_FUA;
263 
264 	return bio_opf;
265 }
266 
rq_to_rnbd_flags(struct request * rq)267 static inline u32 rq_to_rnbd_flags(struct request *rq)
268 {
269 	u32 rnbd_opf;
270 
271 	switch (req_op(rq)) {
272 	case REQ_OP_READ:
273 		rnbd_opf = RNBD_OP_READ;
274 		break;
275 	case REQ_OP_WRITE:
276 		rnbd_opf = RNBD_OP_WRITE;
277 		break;
278 	case REQ_OP_DISCARD:
279 		rnbd_opf = RNBD_OP_DISCARD;
280 		break;
281 	case REQ_OP_SECURE_ERASE:
282 		rnbd_opf = RNBD_OP_SECURE_ERASE;
283 		break;
284 	case REQ_OP_FLUSH:
285 		rnbd_opf = RNBD_OP_FLUSH;
286 		break;
287 	default:
288 		WARN(1, "Unknown request type %d (flags %llu)\n",
289 		     req_op(rq), (unsigned long long)rq->cmd_flags);
290 		rnbd_opf = 0;
291 	}
292 
293 	if (op_is_sync(rq->cmd_flags))
294 		rnbd_opf |= RNBD_F_SYNC;
295 
296 	if (op_is_flush(rq->cmd_flags))
297 		rnbd_opf |= RNBD_F_FUA;
298 
299 	return rnbd_opf;
300 }
301 
302 const char *rnbd_access_mode_str(enum rnbd_access_mode mode);
303 
304 #endif /* RNBD_PROTO_H */
305