1.\" 2.\" Copyright (c) 1998 Kenneth D. Merry. 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. The name of the author may not be used to endorse or promote products 14.\" derived from this software without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" $FreeBSD$ 29.\" 30.\" This man page borrows heavily from the old scsi(3) man page, which had 31.\" the following copyright: 32.\" 33.\" Copyright (c) 1994 HD Associates (hd@world.std.com) 34.\" All rights reserved. 35.\" 36.\" Redistribution and use in source and binary forms, with or without 37.\" modification, are permitted provided that the following conditions 38.\" are met: 39.\" 1. Redistributions of source code must retain the above copyright 40.\" notice, this list of conditions and the following disclaimer. 41.\" 2. Redistributions in binary form must reproduce the above copyright 42.\" notice, this list of conditions and the following disclaimer in the 43.\" documentation and/or other materials provided with the distribution. 44.\" 3. All advertising materials mentioning features or use of this software 45.\" must display the following acknowledgement: 46.\" This product includes software developed by HD Associates 47.\" 4. Neither the name of the HD Associates nor the names of its contributors 48.\" may be used to endorse or promote products derived from this software 49.\" without specific prior written permission. 50.\" 51.\" THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES``AS IS'' AND 52.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 53.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 54.\" ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE 55.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 56.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 57.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 58.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 59.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 60.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 61.\" SUCH DAMAGE. 62.\" 63.\" 64.Dd March 13, 2017 65.Dt CAM_CDBPARSE 3 66.Os 67.Sh NAME 68.Nm csio_build , 69.Nm csio_build_visit , 70.Nm csio_decode , 71.Nm csio_decode_visit , 72.Nm buff_decode , 73.Nm buff_decode_visit , 74.Nm csio_encode , 75.Nm csio_encode_visit , 76.Nm buff_encode_visit 77.Nd CAM user library SCSI buffer parsing routines 78.Sh LIBRARY 79.Lb libcam 80.Sh SYNOPSIS 81.In stdio.h 82.In camlib.h 83.Ft int 84.Fo csio_build 85.Fa "struct ccb_scsiio *csio" 86.Fa "uint8_t *data_ptr" 87.Fa "uint32_t dxfer_len" 88.Fa "uint32_t flags" 89.Fa "int retry_count" 90.Fa "int timeout" 91.Fa "const char *cmd_spec" 92.Fa "..." 93.Fc 94.Ft int 95.Fo csio_build_visit 96.Fa "struct ccb_scsiio *csio" 97.Fa "uint8_t *data_ptr" 98.Fa "uint32_t dxfer_len" 99.Fa "uint32_t flags" 100.Fa "int retry_count" 101.Fa "int timeout" 102.Fa "const char *cmd_spec" 103.Fa "int (*arg_get)(void *hook, char *field_name)" 104.Fa "void *gethook" 105.Fc 106.Ft int 107.Fo csio_decode 108.Fa "struct ccb_scsiio *csio" 109.Fa "const char *fmt" 110.Fa "..." 111.Fc 112.Ft int 113.Fo csio_decode_visit 114.Fa "struct ccb_scsiio *csio" 115.Fa "const char *fmt" 116.Fa "void (*arg_put)(void *hook" 117.Fa "int letter" 118.Fa "void *val" 119.Fa "int count" 120.Fa "char *name)" 121.Fa "void *puthook" 122.Fc 123.Ft int 124.Fo buff_decode 125.Fa "uint8_t *buff" 126.Fa "size_t len" 127.Fa "const char *fmt" 128.Fa "..." 129.Fc 130.Ft int 131.Fo buff_decode_visit 132.Fa "uint8_t *buff" 133.Fa "size_t len" 134.Fa "const char *fmt" 135.Fa "void (*arg_put)(void *, int, void *, int, char *)" 136.Fa "void *puthook" 137.Fc 138.Ft int 139.Fo csio_encode 140.Fa "struct ccb_scsiio *csio" 141.Fa "const char *fmt" 142.Fa "..." 143.Fc 144.Ft int 145.Fo csio_encode_visit 146.Fa "struct ccb_scsiio *csio" 147.Fa "const char *fmt" 148.Fa "int (*arg_get)(void *hook, char *field_name)" 149.Fa "void *gethook" 150.Fc 151.Ft int 152.Fo buff_encode_visit 153.Fa "uint8_t *buff" 154.Fa "size_t len" 155.Fa "const char *fmt" 156.Fa "int (*arg_get)(void *hook, char *field_name)" 157.Fa "void *gethook" 158.Fc 159.Sh DESCRIPTION 160The CAM buffer/CDB encoding and decoding routines provide a relatively easy 161migration path for userland 162.Tn SCSI 163applications written with the similarly-named 164.Va scsireq_ Ns * 165functions from the old 166.Fx 167.Tn SCSI 168layer. 169.Pp 170These functions may be used in new applications, but users may find it 171easier to use the various SCSI CCB building functions included with the 172.Xr cam 3 173library, e.g., \& 174.Fn cam_fill_csio , 175.Fn scsi_start_stop , 176and 177.Fn scsi_read_write . 178.Pp 179.Fn csio_build 180builds up a 181.Va ccb_scsiio 182structure based on the information provided in 183the variable argument list. 184It gracefully handles a NULL 185.Fa data_ptr 186argument passed to it. 187.Pp 188.Fa dxfer_len 189is the length of the data phase; the data transfer direction is 190determined by the 191.Fa flags 192argument. 193.Pp 194.Fa data_ptr 195is the data buffer used during the 196.Tn SCSI 197data phase. 198If no data is to be 199transferred for the 200.Tn SCSI 201command in question, this should be set to NULL. 202If there is data to 203transfer for the command, this buffer must be at least 204.Fa dxfer_len 205long. 206.Pp 207.Fa flags 208are the flags defined in 209.In cam/cam_ccb.h : 210.Bd -literal 211/* Common CCB header */ 212/* CAM CCB flags */ 213typedef enum { 214 CAM_CDB_POINTER = 0x00000001,/* The CDB field is a pointer */ 215 CAM_SCATTER_VALID = 0x00000010,/* Scatter/gather list is valid */ 216 CAM_DIS_AUTOSENSE = 0x00000020,/* Disable autosense feature */ 217 CAM_DIR_RESV = 0x00000000,/* Data direction (00:reserved) */ 218 CAM_DIR_IN = 0x00000040,/* Data direction (01:DATA IN) */ 219 CAM_DIR_OUT = 0x00000080,/* Data direction (10:DATA OUT) */ 220 CAM_DIR_NONE = 0x000000C0,/* Data direction (11:no data) */ 221 CAM_DIR_MASK = 0x000000C0,/* Data direction Mask */ 222 CAM_DEV_QFRZDIS = 0x00000400,/* Disable DEV Q freezing */ 223 CAM_DEV_QFREEZE = 0x00000800,/* Freeze DEV Q on execution */ 224 CAM_HIGH_POWER = 0x00001000,/* Command takes a lot of power */ 225 CAM_SENSE_PTR = 0x00002000,/* Sense data is a pointer */ 226 CAM_SENSE_PHYS = 0x00004000,/* Sense pointer is physical addr*/ 227 CAM_TAG_ACTION_VALID = 0x00008000,/* Use the tag action in this ccb*/ 228 CAM_PASS_ERR_RECOVER = 0x00010000,/* Pass driver does err. recovery*/ 229 CAM_DIS_DISCONNECT = 0x00020000,/* Disable disconnect */ 230 CAM_SG_LIST_PHYS = 0x00040000,/* SG list has physical addrs. */ 231 CAM_DATA_PHYS = 0x00200000,/* SG/Buffer data ptrs are phys. */ 232 CAM_CDB_PHYS = 0x00400000,/* CDB pointer is physical */ 233 234/* Host target Mode flags */ 235 CAM_SEND_SENSE = 0x08000000,/* Send sense data with status */ 236 CAM_SEND_STATUS = 0x80000000,/* Send status after data phase */ 237} ccb_flags; 238.Ed 239.Pp 240Multiple flags should be ORed together. 241Any of the CCB flags may be used, 242although it is worth noting several important ones here: 243.Bl -tag -width CAM_PASS_ERR_RECOVER 244.It Dv CAM_DIR_IN 245This indicates that the operation in question is a read operation. 246i.e., 247data is being read from the 248.Tn SCSI 249device to the user-supplied buffer. 250.It Dv CAM_DIR_OUT 251This indicates that the operation is a write operation. 252i.e., data is being 253written from the user-supplied buffer to the device. 254.It Dv CAM_DIR_NONE 255This indicates that there is no data to be transferred for this command. 256.It Dv CAM_DEV_QFRZDIS 257This flag disables device queue freezing as an error recovery mechanism. 258.It Dv CAM_PASS_ERR_RECOVER 259This flag tells the 260.Xr pass 4 261driver to enable error recovery. 262The default is to not perform error 263recovery, which means that the retry count will not be honored without this 264flag, among other things. 265.It Dv CAM_DATA_PHYS 266This indicates that the address contained in 267.Fa data_ptr 268is a physical address, not a virtual address. 269.El 270.Pp 271The 272.Fa retry_count 273tells the kernel how many times to retry the command in question. 274The 275retry count is ignored unless the 276.Xr pass 4 277driver is told to enable error recovery via the 278.Dv CAM_PASS_ERR_RECOVER 279flag. 280.Pp 281The 282.Fa timeout 283tells the kernel how long to wait for the given command to complete. 284If 285the timeout expires and the command has not completed, the CCB will be 286returned from the kernel with an appropriate error status. 287.Pp 288.Fa cmd_spec 289is a CDB format specifier used to build up the SCSI CDB. 290This text string is made up of a list of field specifiers. 291Field 292specifiers specify the value for each CDB field (including indicating 293that the value be taken from the next argument in the 294variable argument list), the width 295of the field in bits or bytes, and an optional name. 296White space is 297ignored, and the pound sign ('#') introduces a comment that ends at the 298end of the current line. 299.Pp 300The optional name is the first part of a field specifier and 301is in curly braces. 302The text in curly braces in this example are 303the names: 304.Dl "{PS} v:b1 {Reserved} 0:b1 {Page Code} v:b6 # Mode select page" 305.Pp 306This field specifier has two one bit fields and one six bit field. 307The second one bit field is the constant value 0 and the first 308one bit field and the six bit field are taken from the variable 309argument list. 310Multi byte fields are swapped into the SCSI byte order in the 311CDB and white space is ignored. 312.Pp 313When the field is a hex value or the letter v, (e.g., 314.Fa "1A" 315or 316.Fa "v" ) 317then a single byte value 318is copied to the next unused byte of the CDB. 319When the letter 320.Fa v 321is used the next integer argument is taken from the variable argument list 322and that value used. 323.Pp 324A constant hex value followed by a field width specifier or the letter 325.Fa v 326followed by a field width specifier (e.g., 327.Fa 3:4 , 328.Fa 3:b4 , 329.Fa 3:i3 , 330.Fa v:i3 ) 331specifies a field of a given bit or byte width. 332Either the constant value or (for the V specifier) the next integer value from 333the variable argument list is copied to the next unused 334bits or bytes of the CDB. 335.Pp 336A decimal number or the letter 337.Fa b 338followed by a decimal number field width indicates a bit field of that width. 339The bit fields are packed as tightly as possible beginning with the 340high bit (so that it reads the same as the SCSI spec), and a new byte of 341the CDB is started whenever a byte fills completely or when an 342.Fa i 343field is encountered. 344.Pp 345A field width specifier consisting of the letter 346.Fa i 347followed by either 3481, 2, 3 or 4 indicates a 1, 2, 3 or 4 byte integral value that must 349be swapped into SCSI byte order (MSB first). 350.Pp 351For the 352.Fa v 353field specifier the next integer argument is taken from the variable argument 354list and that value is used swapped into SCSI byte order. 355.Pp 356.Fn csio_build_visit 357operates similarly to 358.Fn csio_build , 359except that the values to substitute for variable arguments in 360.Fa cmd_spec 361are retrieved via the 362.Fn arg_get 363function passed in to 364.Fn csio_build_visit 365instead of via 366.Xr stdarg 3 . 367The 368.Fn arg_get 369function takes two arguments: 370.Bl -tag -width field_name 371.It Fa gethook 372is passed into the 373.Fn arg_get 374function at each invocation. 375This enables the 376.Fn arg_get 377function to keep some state in between calls without using global or static 378variables. 379.It Fa field_name 380is the field name supplied in 381.Fa fmt , 382if any. 383.El 384.Pp 385.Fn csio_decode 386is used to decode information from the data in phase of the SCSI 387transfer. 388.Pp 389The decoding is similar to 390the command specifier processing of 391.Fn csio_build 392except that the data is extracted from the data pointed to by 393.Fa csio->data_ptr . 394The stdarg list should be pointers to integers instead of integer 395values. 396A seek field type and a suppression modifier are added. 397The 398.Fa * 399suppression modifier (e.g., 400.Fa *i3 401or 402.Fa *b4 ) 403suppresses assignment from the field and can be used to skip 404over bytes or bits in the data, without having to copy 405them to a dummy variable in the arg list. 406.Pp 407The seek field type 408.Fa s 409permits you to skip over data. 410This seeks to an absolute position 411.Pq Fa s3 412or a relative position 413.Pq Fa s+3 414in the data, based on whether or not the presence of the '+' sign. 415The seek value can be specified as 416.Fa v 417and the next integer value from the argument list will be 418used as the seek value. 419.Pp 420.Fn csio_decode_visit 421operates like 422.Fn csio_decode 423except that instead of placing the decoded contents of the buffer in 424variadic arguments, the decoded buffer contents are returned to the user 425via the 426.Fn arg_put 427function that is passed in. 428The 429.Fn arg_put 430function takes several arguments: 431.Bl -tag -width letter 432.It Fa hook 433The "hook" is a mechanism to allow the 434.Fn arg_put 435function to save state in between calls. 436.It Fa letter 437is the letter describing the format of the argument being passed into the 438function. 439.It Fa val 440is a void pointer to the value being passed into the function. 441.It Fa count 442is the size of the value being passed into the 443.Fn arg_put 444function. 445The argument format determines the unit of measure. 446.It Fa name 447This is a text description of the field, if one was provided in the 448.Fa fmt . 449.El 450.Pp 451.Fn buff_decode 452decodes an arbitrary data buffer using the method 453described above for 454.Fn csio_decode . 455.Pp 456.Fn buff_decode_visit 457decodes an arbitrary data buffer using the method described above for 458.Fn csio_decode_visit . 459.Pp 460.Fn csio_encode 461encodes the 462.Fa data_ptr 463portion (not the CDB!) of a 464.Va ccb_scsiio 465structure, using the method described above for 466.Fn csio_build . 467.Pp 468.Fn csio_encode_visit 469encodes the 470.Fa data_ptr 471portion (not the CDB!) of a 472.Va ccb_scsiio 473structure, using the method described above for 474.Fn csio_build_visit . 475.Pp 476.Fn buff_encode_visit 477encodes an arbitrary data pointer, using the method described 478above for 479.Fn csio_build_visit . 480.Sh RETURN VALUES 481.Fn csio_build , 482.Fn csio_build_visit , 483.Fn csio_encode , 484.Fn csio_encode_visit , 485and 486.Fn buff_encode_visit 487return the number of fields processed. 488.Pp 489.Fn csio_decode , 490.Fn csio_decode_visit , 491.Fn buff_decode , 492and 493.Fn buff_decode_visit 494return the number of assignments performed. 495.Sh SEE ALSO 496.Xr cam 3 , 497.Xr pass 4 , 498.Xr camcontrol 8 499.Sh HISTORY 500The CAM versions of these functions are based upon similar functions 501implemented for the old 502.Fx 503.Tn SCSI 504layer. 505The encoding/decoding functions in the old 506.Tn SCSI 507code were written by 508.An Peter Dufault Aq Mt dufault@hda.com . 509.Pp 510Many systems have comparable interfaces to permit a user to construct a 511SCSI command in user space. 512.Pp 513The old 514.Va scsireq 515data structure was almost identical to the SGI /dev/scsi data structure. 516If anyone knows the name of the authors it should go here; 517Peter Dufault 518first read about it in a 1989 Sun Expert magazine. 519.Pp 520The new CCB data structures are derived from the CAM-2 and CAM-3 521specifications. 522.Pp 523.An Peter Dufault 524implemented a clone of SGI's interface in 525.Bx 386 526that 527led to the original 528.Fx 529.Tn SCSI 530library and the related kernel ioctl. 531If anyone needs that for compatibility, contact 532.Mt dufault@hda.com . 533.Sh AUTHORS 534.An -nosplit 535.An Kenneth Merry Aq Mt ken@FreeBSD.org 536implemented the CAM versions of these encoding and decoding functions. 537This current work is based upon earlier work by 538.An Peter Dufault Aq Mt dufault@hda.com . 539.Sh BUGS 540There should probably be a function that encodes both the CDB and the data 541buffer portions of a 542.Tn SCSI 543CCB. 544I discovered this while implementing the arbitrary command execution 545code in 546.Xr camcontrol 8 , 547but I have not yet had time to implement such a function. 548.Pp 549Some of the CCB flag descriptions really do not belong here. 550Rather they 551belong in a generic CCB man page. 552Since that man page has not yet been 553written, the shorter descriptions here will have to suffice. 554