1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * SCSI functions used by both the initiator and the target code.
4 */
5
6 #include <linux/bug.h>
7 #include <linux/kernel.h>
8 #include <linux/string.h>
9 #include <linux/errno.h>
10 #include <linux/module.h>
11 #include <asm/unaligned.h>
12 #include <scsi/scsi_common.h>
13
14 MODULE_LICENSE("GPL v2");
15
16 /* Command group 3 is reserved and should never be used. */
17 const unsigned char scsi_command_size_tbl[8] = {
18 6, 10, 10, 12, 16, 12, 10, 10
19 };
20 EXPORT_SYMBOL(scsi_command_size_tbl);
21
22 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
23 * You may not alter any existing entry (although adding new ones is
24 * encouraged once assigned by ANSI/INCITS T10).
25 */
26 static const char *const scsi_device_types[] = {
27 "Direct-Access ",
28 "Sequential-Access",
29 "Printer ",
30 "Processor ",
31 "WORM ",
32 "CD-ROM ",
33 "Scanner ",
34 "Optical Device ",
35 "Medium Changer ",
36 "Communications ",
37 "ASC IT8 ",
38 "ASC IT8 ",
39 "RAID ",
40 "Enclosure ",
41 "Direct-Access-RBC",
42 "Optical card ",
43 "Bridge controller",
44 "Object storage ",
45 "Automation/Drive ",
46 "Security Manager ",
47 "Direct-Access-ZBC",
48 };
49
50 /**
51 * scsi_device_type - Return 17-char string indicating device type.
52 * @type: type number to look up
53 */
scsi_device_type(unsigned type)54 const char *scsi_device_type(unsigned type)
55 {
56 if (type == 0x1e)
57 return "Well-known LUN ";
58 if (type == 0x1f)
59 return "No Device ";
60 if (type >= ARRAY_SIZE(scsi_device_types))
61 return "Unknown ";
62 return scsi_device_types[type];
63 }
64 EXPORT_SYMBOL(scsi_device_type);
65
66 /**
67 * scsilun_to_int - convert a scsi_lun to an int
68 * @scsilun: struct scsi_lun to be converted.
69 *
70 * Description:
71 * Convert @scsilun from a struct scsi_lun to a four-byte host byte-ordered
72 * integer, and return the result. The caller must check for
73 * truncation before using this function.
74 *
75 * Notes:
76 * For a description of the LUN format, post SCSI-3 see the SCSI
77 * Architecture Model, for SCSI-3 see the SCSI Controller Commands.
78 *
79 * Given a struct scsi_lun of: d2 04 0b 03 00 00 00 00, this function
80 * returns the integer: 0x0b03d204
81 *
82 * This encoding will return a standard integer LUN for LUNs smaller
83 * than 256, which typically use a single level LUN structure with
84 * addressing method 0.
85 */
scsilun_to_int(struct scsi_lun * scsilun)86 u64 scsilun_to_int(struct scsi_lun *scsilun)
87 {
88 int i;
89 u64 lun;
90
91 lun = 0;
92 for (i = 0; i < sizeof(lun); i += 2)
93 lun = lun | (((u64)scsilun->scsi_lun[i] << ((i + 1) * 8)) |
94 ((u64)scsilun->scsi_lun[i + 1] << (i * 8)));
95 return lun;
96 }
97 EXPORT_SYMBOL(scsilun_to_int);
98
99 /**
100 * int_to_scsilun - reverts an int into a scsi_lun
101 * @lun: integer to be reverted
102 * @scsilun: struct scsi_lun to be set.
103 *
104 * Description:
105 * Reverts the functionality of the scsilun_to_int, which packed
106 * an 8-byte lun value into an int. This routine unpacks the int
107 * back into the lun value.
108 *
109 * Notes:
110 * Given an integer : 0x0b03d204, this function returns a
111 * struct scsi_lun of: d2 04 0b 03 00 00 00 00
112 *
113 */
int_to_scsilun(u64 lun,struct scsi_lun * scsilun)114 void int_to_scsilun(u64 lun, struct scsi_lun *scsilun)
115 {
116 int i;
117
118 memset(scsilun->scsi_lun, 0, sizeof(scsilun->scsi_lun));
119
120 for (i = 0; i < sizeof(lun); i += 2) {
121 scsilun->scsi_lun[i] = (lun >> 8) & 0xFF;
122 scsilun->scsi_lun[i+1] = lun & 0xFF;
123 lun = lun >> 16;
124 }
125 }
126 EXPORT_SYMBOL(int_to_scsilun);
127
128 /**
129 * scsi_normalize_sense - normalize main elements from either fixed or
130 * descriptor sense data format into a common format.
131 *
132 * @sense_buffer: byte array containing sense data returned by device
133 * @sb_len: number of valid bytes in sense_buffer
134 * @sshdr: pointer to instance of structure that common
135 * elements are written to.
136 *
137 * Notes:
138 * The "main elements" from sense data are: response_code, sense_key,
139 * asc, ascq and additional_length (only for descriptor format).
140 *
141 * Typically this function can be called after a device has
142 * responded to a SCSI command with the CHECK_CONDITION status.
143 *
144 * Return value:
145 * true if valid sense data information found, else false;
146 */
scsi_normalize_sense(const u8 * sense_buffer,int sb_len,struct scsi_sense_hdr * sshdr)147 bool scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
148 struct scsi_sense_hdr *sshdr)
149 {
150 memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
151
152 if (!sense_buffer || !sb_len)
153 return false;
154
155 sshdr->response_code = (sense_buffer[0] & 0x7f);
156
157 if (!scsi_sense_valid(sshdr))
158 return false;
159
160 if (sshdr->response_code >= 0x72) {
161 /*
162 * descriptor format
163 */
164 if (sb_len > 1)
165 sshdr->sense_key = (sense_buffer[1] & 0xf);
166 if (sb_len > 2)
167 sshdr->asc = sense_buffer[2];
168 if (sb_len > 3)
169 sshdr->ascq = sense_buffer[3];
170 if (sb_len > 7)
171 sshdr->additional_length = sense_buffer[7];
172 } else {
173 /*
174 * fixed format
175 */
176 if (sb_len > 2)
177 sshdr->sense_key = (sense_buffer[2] & 0xf);
178 if (sb_len > 7) {
179 sb_len = (sb_len < (sense_buffer[7] + 8)) ?
180 sb_len : (sense_buffer[7] + 8);
181 if (sb_len > 12)
182 sshdr->asc = sense_buffer[12];
183 if (sb_len > 13)
184 sshdr->ascq = sense_buffer[13];
185 }
186 }
187
188 return true;
189 }
190 EXPORT_SYMBOL(scsi_normalize_sense);
191
192 /**
193 * scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
194 * @sense_buffer: byte array of descriptor format sense data
195 * @sb_len: number of valid bytes in sense_buffer
196 * @desc_type: value of descriptor type to find
197 * (e.g. 0 -> information)
198 *
199 * Notes:
200 * only valid when sense data is in descriptor format
201 *
202 * Return value:
203 * pointer to start of (first) descriptor if found else NULL
204 */
scsi_sense_desc_find(const u8 * sense_buffer,int sb_len,int desc_type)205 const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
206 int desc_type)
207 {
208 int add_sen_len, add_len, desc_len, k;
209 const u8 * descp;
210
211 if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
212 return NULL;
213 if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
214 return NULL;
215 add_sen_len = (add_sen_len < (sb_len - 8)) ?
216 add_sen_len : (sb_len - 8);
217 descp = &sense_buffer[8];
218 for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
219 descp += desc_len;
220 add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
221 desc_len = add_len + 2;
222 if (descp[0] == desc_type)
223 return descp;
224 if (add_len < 0) // short descriptor ??
225 break;
226 }
227 return NULL;
228 }
229 EXPORT_SYMBOL(scsi_sense_desc_find);
230
231 /**
232 * scsi_build_sense_buffer - build sense data in a buffer
233 * @desc: Sense format (non-zero == descriptor format,
234 * 0 == fixed format)
235 * @buf: Where to build sense data
236 * @key: Sense key
237 * @asc: Additional sense code
238 * @ascq: Additional sense code qualifier
239 *
240 **/
scsi_build_sense_buffer(int desc,u8 * buf,u8 key,u8 asc,u8 ascq)241 void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
242 {
243 if (desc) {
244 buf[0] = 0x72; /* descriptor, current */
245 buf[1] = key;
246 buf[2] = asc;
247 buf[3] = ascq;
248 buf[7] = 0;
249 } else {
250 buf[0] = 0x70; /* fixed, current */
251 buf[2] = key;
252 buf[7] = 0xa;
253 buf[12] = asc;
254 buf[13] = ascq;
255 }
256 }
257 EXPORT_SYMBOL(scsi_build_sense_buffer);
258
259 /**
260 * scsi_set_sense_information - set the information field in a
261 * formatted sense data buffer
262 * @buf: Where to build sense data
263 * @buf_len: buffer length
264 * @info: 64-bit information value to be set
265 *
266 * Return value:
267 * 0 on success or -EINVAL for invalid sense buffer length
268 **/
scsi_set_sense_information(u8 * buf,int buf_len,u64 info)269 int scsi_set_sense_information(u8 *buf, int buf_len, u64 info)
270 {
271 if ((buf[0] & 0x7f) == 0x72) {
272 u8 *ucp, len;
273
274 len = buf[7];
275 ucp = (char *)scsi_sense_desc_find(buf, len + 8, 0);
276 if (!ucp) {
277 buf[7] = len + 0xc;
278 ucp = buf + 8 + len;
279 }
280
281 if (buf_len < len + 0xc)
282 /* Not enough room for info */
283 return -EINVAL;
284
285 ucp[0] = 0;
286 ucp[1] = 0xa;
287 ucp[2] = 0x80; /* Valid bit */
288 ucp[3] = 0;
289 put_unaligned_be64(info, &ucp[4]);
290 } else if ((buf[0] & 0x7f) == 0x70) {
291 /*
292 * Only set the 'VALID' bit if we can represent the value
293 * correctly; otherwise just fill out the lower bytes and
294 * clear the 'VALID' flag.
295 */
296 if (info <= 0xffffffffUL)
297 buf[0] |= 0x80;
298 else
299 buf[0] &= 0x7f;
300 put_unaligned_be32((u32)info, &buf[3]);
301 }
302
303 return 0;
304 }
305 EXPORT_SYMBOL(scsi_set_sense_information);
306
307 /**
308 * scsi_set_sense_field_pointer - set the field pointer sense key
309 * specific information in a formatted sense data buffer
310 * @buf: Where to build sense data
311 * @buf_len: buffer length
312 * @fp: field pointer to be set
313 * @bp: bit pointer to be set
314 * @cd: command/data bit
315 *
316 * Return value:
317 * 0 on success or -EINVAL for invalid sense buffer length
318 */
scsi_set_sense_field_pointer(u8 * buf,int buf_len,u16 fp,u8 bp,bool cd)319 int scsi_set_sense_field_pointer(u8 *buf, int buf_len, u16 fp, u8 bp, bool cd)
320 {
321 u8 *ucp, len;
322
323 if ((buf[0] & 0x7f) == 0x72) {
324 len = buf[7];
325 ucp = (char *)scsi_sense_desc_find(buf, len + 8, 2);
326 if (!ucp) {
327 buf[7] = len + 8;
328 ucp = buf + 8 + len;
329 }
330
331 if (buf_len < len + 8)
332 /* Not enough room for info */
333 return -EINVAL;
334
335 ucp[0] = 2;
336 ucp[1] = 6;
337 ucp[4] = 0x80; /* Valid bit */
338 if (cd)
339 ucp[4] |= 0x40;
340 if (bp < 0x8)
341 ucp[4] |= 0x8 | bp;
342 put_unaligned_be16(fp, &ucp[5]);
343 } else if ((buf[0] & 0x7f) == 0x70) {
344 len = buf[7];
345 if (len < 18)
346 buf[7] = 18;
347
348 buf[15] = 0x80;
349 if (cd)
350 buf[15] |= 0x40;
351 if (bp < 0x8)
352 buf[15] |= 0x8 | bp;
353 put_unaligned_be16(fp, &buf[16]);
354 }
355
356 return 0;
357 }
358 EXPORT_SYMBOL(scsi_set_sense_field_pointer);
359