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.\" This man page borrows heavily from the old scsi(3) man page, which had 29.\" the following copyright: 30.\" 31.\" Copyright (c) 1994 HD Associates (hd@world.std.com) 32.\" All rights reserved. 33.\" 34.\" Redistribution and use in source and binary forms, with or without 35.\" modification, are permitted provided that the following conditions 36.\" are met: 37.\" 1. Redistributions of source code must retain the above copyright 38.\" notice, this list of conditions and the following disclaimer. 39.\" 2. Redistributions in binary form must reproduce the above copyright 40.\" notice, this list of conditions and the following disclaimer in the 41.\" documentation and/or other materials provided with the distribution. 42.\" 3. All advertising materials mentioning features or use of this software 43.\" must display the following acknowledgement: 44.\" This product includes software developed by HD Associates 45.\" 4. Neither the name of the HD Associates nor the names of its contributors 46.\" may be used to endorse or promote products derived from this software 47.\" without specific prior written permission. 48.\" 49.\" THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES``AS IS'' AND 50.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52.\" ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE 53.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59.\" SUCH DAMAGE. 60.\" 61.\" 62.Dd March 13, 2017 63.Dt CAM_CDBPARSE 3 64.Os 65.Sh NAME 66.Nm csio_build , 67.Nm csio_build_visit , 68.Nm csio_decode , 69.Nm csio_decode_visit , 70.Nm buff_decode , 71.Nm buff_decode_visit , 72.Nm csio_encode , 73.Nm csio_encode_visit , 74.Nm buff_encode_visit 75.Nd CAM user library SCSI buffer parsing routines 76.Sh LIBRARY 77.Lb libcam 78.Sh SYNOPSIS 79.In stdio.h 80.In camlib.h 81.Ft int 82.Fo csio_build 83.Fa "struct ccb_scsiio *csio" 84.Fa "uint8_t *data_ptr" 85.Fa "uint32_t dxfer_len" 86.Fa "uint32_t flags" 87.Fa "int retry_count" 88.Fa "int timeout" 89.Fa "const char *cmd_spec" 90.Fa "..." 91.Fc 92.Ft int 93.Fo csio_build_visit 94.Fa "struct ccb_scsiio *csio" 95.Fa "uint8_t *data_ptr" 96.Fa "uint32_t dxfer_len" 97.Fa "uint32_t flags" 98.Fa "int retry_count" 99.Fa "int timeout" 100.Fa "const char *cmd_spec" 101.Fa "int (*arg_get)(void *hook, char *field_name)" 102.Fa "void *gethook" 103.Fc 104.Ft int 105.Fo csio_decode 106.Fa "struct ccb_scsiio *csio" 107.Fa "const char *fmt" 108.Fa "..." 109.Fc 110.Ft int 111.Fo csio_decode_visit 112.Fa "struct ccb_scsiio *csio" 113.Fa "const char *fmt" 114.Fa "void (*arg_put)(void *hook" 115.Fa "int letter" 116.Fa "void *val" 117.Fa "int count" 118.Fa "char *name)" 119.Fa "void *puthook" 120.Fc 121.Ft int 122.Fo buff_decode 123.Fa "uint8_t *buff" 124.Fa "size_t len" 125.Fa "const char *fmt" 126.Fa "..." 127.Fc 128.Ft int 129.Fo buff_decode_visit 130.Fa "uint8_t *buff" 131.Fa "size_t len" 132.Fa "const char *fmt" 133.Fa "void (*arg_put)(void *, int, void *, int, char *)" 134.Fa "void *puthook" 135.Fc 136.Ft int 137.Fo csio_encode 138.Fa "struct ccb_scsiio *csio" 139.Fa "const char *fmt" 140.Fa "..." 141.Fc 142.Ft int 143.Fo csio_encode_visit 144.Fa "struct ccb_scsiio *csio" 145.Fa "const char *fmt" 146.Fa "int (*arg_get)(void *hook, char *field_name)" 147.Fa "void *gethook" 148.Fc 149.Ft int 150.Fo buff_encode_visit 151.Fa "uint8_t *buff" 152.Fa "size_t len" 153.Fa "const char *fmt" 154.Fa "int (*arg_get)(void *hook, char *field_name)" 155.Fa "void *gethook" 156.Fc 157.Sh DESCRIPTION 158The CAM buffer/CDB encoding and decoding routines provide a relatively easy 159migration path for userland 160.Tn SCSI 161applications written with the similarly-named 162.Va scsireq_ Ns * 163functions from the old 164.Fx 165.Tn SCSI 166layer. 167.Pp 168These functions may be used in new applications, but users may find it 169easier to use the various SCSI CCB building functions included with the 170.Xr cam 3 171library, e.g., \& 172.Fn cam_fill_csio , 173.Fn scsi_start_stop , 174and 175.Fn scsi_read_write . 176.Pp 177.Fn csio_build 178builds up a 179.Va ccb_scsiio 180structure based on the information provided in 181the variable argument list. 182It gracefully handles a NULL 183.Fa data_ptr 184argument passed to it. 185.Pp 186.Fa dxfer_len 187is the length of the data phase; the data transfer direction is 188determined by the 189.Fa flags 190argument. 191.Pp 192.Fa data_ptr 193is the data buffer used during the 194.Tn SCSI 195data phase. 196If no data is to be 197transferred for the 198.Tn SCSI 199command in question, this should be set to NULL. 200If there is data to 201transfer for the command, this buffer must be at least 202.Fa dxfer_len 203long. 204.Pp 205.Fa flags 206are the flags defined in 207.In cam/cam_ccb.h : 208.Bd -literal 209/* Common CCB header */ 210/* CAM CCB flags */ 211typedef enum { 212 CAM_CDB_POINTER = 0x00000001,/* The CDB field is a pointer */ 213 CAM_SCATTER_VALID = 0x00000010,/* Scatter/gather list is valid */ 214 CAM_DIS_AUTOSENSE = 0x00000020,/* Disable autosense feature */ 215 CAM_DIR_RESV = 0x00000000,/* Data direction (00:reserved) */ 216 CAM_DIR_IN = 0x00000040,/* Data direction (01:DATA IN) */ 217 CAM_DIR_OUT = 0x00000080,/* Data direction (10:DATA OUT) */ 218 CAM_DIR_NONE = 0x000000C0,/* Data direction (11:no data) */ 219 CAM_DIR_MASK = 0x000000C0,/* Data direction Mask */ 220 CAM_DEV_QFRZDIS = 0x00000400,/* Disable DEV Q freezing */ 221 CAM_DEV_QFREEZE = 0x00000800,/* Freeze DEV Q on execution */ 222 CAM_HIGH_POWER = 0x00001000,/* Command takes a lot of power */ 223 CAM_SENSE_PTR = 0x00002000,/* Sense data is a pointer */ 224 CAM_SENSE_PHYS = 0x00004000,/* Sense pointer is physical addr*/ 225 CAM_TAG_ACTION_VALID = 0x00008000,/* Use the tag action in this ccb*/ 226 CAM_PASS_ERR_RECOVER = 0x00010000,/* Pass driver does err. recovery*/ 227 CAM_DIS_DISCONNECT = 0x00020000,/* Disable disconnect */ 228 CAM_SG_LIST_PHYS = 0x00040000,/* SG list has physical addrs. */ 229 CAM_DATA_PHYS = 0x00200000,/* SG/Buffer data ptrs are phys. */ 230 CAM_CDB_PHYS = 0x00400000,/* CDB pointer is physical */ 231 232/* Host target Mode flags */ 233 CAM_SEND_SENSE = 0x08000000,/* Send sense data with status */ 234 CAM_SEND_STATUS = 0x80000000,/* Send status after data phase */ 235} ccb_flags; 236.Ed 237.Pp 238Multiple flags should be ORed together. 239Any of the CCB flags may be used, 240although it is worth noting several important ones here: 241.Bl -tag -width CAM_PASS_ERR_RECOVER 242.It Dv CAM_DIR_IN 243This indicates that the operation in question is a read operation. 244i.e., 245data is being read from the 246.Tn SCSI 247device to the user-supplied buffer. 248.It Dv CAM_DIR_OUT 249This indicates that the operation is a write operation. 250i.e., data is being 251written from the user-supplied buffer to the device. 252.It Dv CAM_DIR_NONE 253This indicates that there is no data to be transferred for this command. 254.It Dv CAM_DEV_QFRZDIS 255This flag disables device queue freezing as an error recovery mechanism. 256.It Dv CAM_PASS_ERR_RECOVER 257This flag tells the 258.Xr pass 4 259driver to enable error recovery. 260The default is to not perform error 261recovery, which means that the retry count will not be honored without this 262flag, among other things. 263.It Dv CAM_DATA_PHYS 264This indicates that the address contained in 265.Fa data_ptr 266is a physical address, not a virtual address. 267.El 268.Pp 269The 270.Fa retry_count 271tells the kernel how many times to retry the command in question. 272The 273retry count is ignored unless the 274.Xr pass 4 275driver is told to enable error recovery via the 276.Dv CAM_PASS_ERR_RECOVER 277flag. 278.Pp 279The 280.Fa timeout 281tells the kernel how long to wait for the given command to complete. 282If 283the timeout expires and the command has not completed, the CCB will be 284returned from the kernel with an appropriate error status. 285.Pp 286.Fa cmd_spec 287is a CDB format specifier used to build up the SCSI CDB. 288This text string is made up of a list of field specifiers. 289Field 290specifiers specify the value for each CDB field (including indicating 291that the value be taken from the next argument in the 292variable argument list), the width 293of the field in bits or bytes, and an optional name. 294White space is 295ignored, and the pound sign ('#') introduces a comment that ends at the 296end of the current line. 297.Pp 298The optional name is the first part of a field specifier and 299is in curly braces. 300The text in curly braces in this example are 301the names: 302.Dl "{PS} v:b1 {Reserved} 0:b1 {Page Code} v:b6 # Mode select page" 303.Pp 304This field specifier has two one bit fields and one six bit field. 305The second one bit field is the constant value 0 and the first 306one bit field and the six bit field are taken from the variable 307argument list. 308Multi byte fields are swapped into the SCSI byte order in the 309CDB and white space is ignored. 310.Pp 311When the field is a hex value or the letter v, (e.g., 312.Fa "1A" 313or 314.Fa "v" ) 315then a single byte value 316is copied to the next unused byte of the CDB. 317When the letter 318.Fa v 319is used the next integer argument is taken from the variable argument list 320and that value used. 321.Pp 322A constant hex value followed by a field width specifier or the letter 323.Fa v 324followed by a field width specifier (e.g., 325.Fa 3:4 , 326.Fa 3:b4 , 327.Fa 3:i3 , 328.Fa v:i3 ) 329specifies a field of a given bit or byte width. 330Either the constant value or (for the V specifier) the next integer value from 331the variable argument list is copied to the next unused 332bits or bytes of the CDB. 333.Pp 334A decimal number or the letter 335.Fa b 336followed by a decimal number field width indicates a bit field of that width. 337The bit fields are packed as tightly as possible beginning with the 338high bit (so that it reads the same as the SCSI spec), and a new byte of 339the CDB is started whenever a byte fills completely or when an 340.Fa i 341field is encountered. 342.Pp 343A field width specifier consisting of the letter 344.Fa i 345followed by either 3461, 2, 3 or 4 indicates a 1, 2, 3 or 4 byte integral value that must 347be swapped into SCSI byte order (MSB first). 348.Pp 349For the 350.Fa v 351field specifier the next integer argument is taken from the variable argument 352list and that value is used swapped into SCSI byte order. 353.Pp 354.Fn csio_build_visit 355operates similarly to 356.Fn csio_build , 357except that the values to substitute for variable arguments in 358.Fa cmd_spec 359are retrieved via the 360.Fn arg_get 361function passed in to 362.Fn csio_build_visit 363instead of via 364.Xr stdarg 3 . 365The 366.Fn arg_get 367function takes two arguments: 368.Bl -tag -width field_name 369.It Fa gethook 370is passed into the 371.Fn arg_get 372function at each invocation. 373This enables the 374.Fn arg_get 375function to keep some state in between calls without using global or static 376variables. 377.It Fa field_name 378is the field name supplied in 379.Fa fmt , 380if any. 381.El 382.Pp 383.Fn csio_decode 384is used to decode information from the data in phase of the SCSI 385transfer. 386.Pp 387The decoding is similar to 388the command specifier processing of 389.Fn csio_build 390except that the data is extracted from the data pointed to by 391.Fa csio->data_ptr . 392The stdarg list should be pointers to integers instead of integer 393values. 394A seek field type and a suppression modifier are added. 395The 396.Fa * 397suppression modifier (e.g., 398.Fa *i3 399or 400.Fa *b4 ) 401suppresses assignment from the field and can be used to skip 402over bytes or bits in the data, without having to copy 403them to a dummy variable in the arg list. 404.Pp 405The seek field type 406.Fa s 407permits you to skip over data. 408This seeks to an absolute position 409.Pq Fa s3 410or a relative position 411.Pq Fa s+3 412in the data, based on whether or not the presence of the '+' sign. 413The seek value can be specified as 414.Fa v 415and the next integer value from the argument list will be 416used as the seek value. 417.Pp 418.Fn csio_decode_visit 419operates like 420.Fn csio_decode 421except that instead of placing the decoded contents of the buffer in 422variadic arguments, the decoded buffer contents are returned to the user 423via the 424.Fn arg_put 425function that is passed in. 426The 427.Fn arg_put 428function takes several arguments: 429.Bl -tag -width letter 430.It Fa hook 431The "hook" is a mechanism to allow the 432.Fn arg_put 433function to save state in between calls. 434.It Fa letter 435is the letter describing the format of the argument being passed into the 436function. 437.It Fa val 438is a void pointer to the value being passed into the function. 439.It Fa count 440is the size of the value being passed into the 441.Fn arg_put 442function. 443The argument format determines the unit of measure. 444.It Fa name 445This is a text description of the field, if one was provided in the 446.Fa fmt . 447.El 448.Pp 449.Fn buff_decode 450decodes an arbitrary data buffer using the method 451described above for 452.Fn csio_decode . 453.Pp 454.Fn buff_decode_visit 455decodes an arbitrary data buffer using the method described above for 456.Fn csio_decode_visit . 457.Pp 458.Fn csio_encode 459encodes the 460.Fa data_ptr 461portion (not the CDB!) of a 462.Va ccb_scsiio 463structure, using the method described above for 464.Fn csio_build . 465.Pp 466.Fn csio_encode_visit 467encodes the 468.Fa data_ptr 469portion (not the CDB!) of a 470.Va ccb_scsiio 471structure, using the method described above for 472.Fn csio_build_visit . 473.Pp 474.Fn buff_encode_visit 475encodes an arbitrary data pointer, using the method described 476above for 477.Fn csio_build_visit . 478.Sh RETURN VALUES 479.Fn csio_build , 480.Fn csio_build_visit , 481.Fn csio_encode , 482.Fn csio_encode_visit , 483and 484.Fn buff_encode_visit 485return the number of fields processed. 486.Pp 487.Fn csio_decode , 488.Fn csio_decode_visit , 489.Fn buff_decode , 490and 491.Fn buff_decode_visit 492return the number of assignments performed. 493.Sh SEE ALSO 494.Xr cam 3 , 495.Xr pass 4 , 496.Xr camcontrol 8 497.Sh HISTORY 498The CAM versions of these functions are based upon similar functions 499implemented for the old 500.Fx 501.Tn SCSI 502layer. 503The encoding/decoding functions in the old 504.Tn SCSI 505code were written by 506.An Peter Dufault Aq Mt dufault@hda.com . 507.Pp 508Many systems have comparable interfaces to permit a user to construct a 509SCSI command in user space. 510.Pp 511The old 512.Va scsireq 513data structure was almost identical to the SGI /dev/scsi data structure. 514If anyone knows the name of the authors it should go here; 515Peter Dufault 516first read about it in a 1989 Sun Expert magazine. 517.Pp 518The new CCB data structures are derived from the CAM-2 and CAM-3 519specifications. 520.Pp 521.An Peter Dufault 522implemented a clone of SGI's interface in 523.Bx 386 524that 525led to the original 526.Fx 527.Tn SCSI 528library and the related kernel ioctl. 529If anyone needs that for compatibility, contact 530.Mt dufault@hda.com . 531.Sh AUTHORS 532.An -nosplit 533.An Kenneth Merry Aq Mt ken@FreeBSD.org 534implemented the CAM versions of these encoding and decoding functions. 535This current work is based upon earlier work by 536.An Peter Dufault Aq Mt dufault@hda.com . 537.Sh BUGS 538There should probably be a function that encodes both the CDB and the data 539buffer portions of a 540.Tn SCSI 541CCB. 542I discovered this while implementing the arbitrary command execution 543code in 544.Xr camcontrol 8 , 545but I have not yet had time to implement such a function. 546.Pp 547Some of the CCB flag descriptions really do not belong here. 548Rather they 549belong in a generic CCB man page. 550Since that man page has not yet been 551written, the shorter descriptions here will have to suffice. 552