/*
 *  Copyright (C) 2002 - 2003 Ardis Technologies <roman@ardistech.com>
 *  Copyright (C) 2007 - 2018 Vladislav Bolkhovitin
 *  Copyright (C) 2007 - 2018 Western Digital Corporation
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation, version 2
 *  of the License.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU General Public License for more details.
 */

#ifndef __ISCSI_HDR_H__
#define __ISCSI_HDR_H__

#include <linux/types.h>
#include <asm/byteorder.h>

#define ISCSI_VERSION			0

#ifndef __packed
#error The macro __packed has not been defined.
#endif

/* iSCSI command PDU header. See also section 10.3 in RFC 3720. */
struct iscsi_hdr {
	u8  opcode;			/* 0 */
	u8  flags;
	u8  spec1[2];
#if defined(__BIG_ENDIAN_BITFIELD)
	struct {			/* 4 */
		unsigned ahslength:8;
		unsigned datalength:24;
	} length;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
	__be32 length;			/* 4 */
#endif
	__be64 lun;			/* 8 */
	__be32 itt;			/* 16 */
	__be32 ttt;			/* 20 */

	/*
	 * SN fields most time stay converted to the CPU form and only received
	 * and send in the BE form.
	 */
	u32 sn;				/* 24 */
	u32 exp_sn;			/* 28 */
	u32 max_sn;			/* 32 */

	__be32 spec3[3];			/* 36 */
} __packed;				/* 48 */

/* Opcode encoding bits */
#define ISCSI_OP_RETRY			0x80
#define ISCSI_OP_IMMEDIATE		0x40
#define ISCSI_OPCODE_MASK		0x3F

/* Client to Server Message Opcode values */
#define ISCSI_OP_NOP_OUT		0x00
#define ISCSI_OP_SCSI_CMD		0x01
#define ISCSI_OP_SCSI_TASK_MGT_MSG	0x02
#define ISCSI_OP_LOGIN_CMD		0x03
#define ISCSI_OP_TEXT_CMD		0x04
#define ISCSI_OP_SCSI_DATA_OUT		0x05
#define ISCSI_OP_LOGOUT_CMD		0x06
#define ISCSI_OP_SNACK_CMD		0x10

/* Server to Client Message Opcode values */
#define ISCSI_OP_NOP_IN			0x20
#define ISCSI_OP_SCSI_RSP		0x21
#define ISCSI_OP_SCSI_TASK_MGT_RSP	0x22
#define ISCSI_OP_LOGIN_RSP		0x23
#define ISCSI_OP_TEXT_RSP		0x24
#define ISCSI_OP_SCSI_DATA_IN		0x25
#define ISCSI_OP_LOGOUT_RSP		0x26
#define ISCSI_OP_R2T			0x31
#define ISCSI_OP_ASYNC_MSG		0x32
#define ISCSI_OP_REJECT			0x3f

struct iscsi_ahs_hdr {
	__be16 ahslength;
	u8 ahstype;
} __packed;

#define ISCSI_AHSTYPE_CDB		1
#define ISCSI_AHSTYPE_RLENGTH		2

union iscsi_sid {
	struct {
		u8 isid[6];		/* Initiator Session ID */
		__be16 tsih;		/* Target Session ID */
	} id;
	__be64 id64;
} __packed;

struct iscsi_scsi_cmd_hdr {
	u8  opcode;
	u8  flags;
	__be16 rsvd1;
	u8  ahslength;
	u8  datalength[3];
	__be64 lun;
	__be32 itt;
	__be32 data_length;
	u32 cmd_sn;
	u32 exp_stat_sn;
	u8  scb[16];
} __packed;

#define ISCSI_CMD_FINAL		0x80
#define ISCSI_CMD_READ		0x40
#define ISCSI_CMD_WRITE		0x20
#define ISCSI_CMD_ATTR_MASK	0x07
#define ISCSI_CMD_UNTAGGED	0x00
#define ISCSI_CMD_SIMPLE	0x01
#define ISCSI_CMD_ORDERED	0x02
#define ISCSI_CMD_HEAD_OF_QUEUE	0x03
#define ISCSI_CMD_ACA		0x04

struct iscsi_cdb_ahdr {
	__be16 ahslength;
	u8  ahstype;
	u8  reserved;
	u8  cdb[0];
} __packed;

struct iscsi_rlength_ahdr {
	__be16 ahslength;
	u8  ahstype;
	u8  reserved;
	__be32 read_length;
} __packed;

struct iscsi_scsi_rsp_hdr {
	u8  opcode;
	u8  flags;
	u8  response;
	u8  cmd_status;
	u8  ahslength;
	u8  datalength[3];
	u32 rsvd1[2];
	__be32 itt;
	__be32 snack;
	u32 stat_sn;
	u32 exp_cmd_sn;
	u32 max_cmd_sn;
	u32 exp_data_sn;
	__be32 bi_residual_count;
	__be32 residual_count;
} __packed;

#define ISCSI_FLG_RESIDUAL_UNDERFLOW		0x02
#define ISCSI_FLG_RESIDUAL_OVERFLOW		0x04
#define ISCSI_FLG_BIRESIDUAL_UNDERFLOW		0x08
#define ISCSI_FLG_BIRESIDUAL_OVERFLOW		0x10

#define ISCSI_RESPONSE_COMMAND_COMPLETED	0x00
#define ISCSI_RESPONSE_TARGET_FAILURE		0x01

struct iscsi_sense_data {
	__be16 length;
	u8  data[0];
} __packed;

struct iscsi_task_mgt_hdr {
	u8  opcode;
	u8  function;
	__be16 rsvd1;
	u8  ahslength;
	u8  datalength[3];
	__be64 lun;
	__be32 itt;
	__be32 rtt;
	u32 cmd_sn;
	u32 exp_stat_sn;
	u32 ref_cmd_sn;
	u32 exp_data_sn;
	u32 rsvd2[2];
} __packed;

#define ISCSI_FUNCTION_MASK			0x7f

#define ISCSI_FUNCTION_ABORT_TASK		1
#define ISCSI_FUNCTION_ABORT_TASK_SET		2
#define ISCSI_FUNCTION_CLEAR_ACA		3
#define ISCSI_FUNCTION_CLEAR_TASK_SET		4
#define ISCSI_FUNCTION_LOGICAL_UNIT_RESET	5
#define ISCSI_FUNCTION_TARGET_WARM_RESET	6
#define ISCSI_FUNCTION_TARGET_COLD_RESET	7
#define ISCSI_FUNCTION_TASK_REASSIGN		8

struct iscsi_task_rsp_hdr {
	u8  opcode;
	u8  flags;
	u8  response;
	u8  rsvd1;
	u8  ahslength;
	u8  datalength[3];
	u32 rsvd2[2];
	__be32 itt;
	u32 rsvd3;
	u32 stat_sn;
	u32 exp_cmd_sn;
	u32 max_cmd_sn;
	u32 rsvd4[3];
} __packed;

#define ISCSI_RESPONSE_FUNCTION_COMPLETE	0
#define ISCSI_RESPONSE_UNKNOWN_TASK		1
#define ISCSI_RESPONSE_UNKNOWN_LUN		2
#define ISCSI_RESPONSE_TASK_ALLEGIANT		3
#define ISCSI_RESPONSE_ALLEGIANCE_REASSIGNMENT_UNSUPPORTED	4
#define ISCSI_RESPONSE_FUNCTION_UNSUPPORTED	5
#define ISCSI_RESPONSE_NO_AUTHORIZATION		6
#define ISCSI_RESPONSE_FUNCTION_REJECTED	255

struct iscsi_data_out_hdr {
	u8  opcode;
	u8  flags;
	u16 rsvd1;
	u8  ahslength;
	u8  datalength[3];
	__be64 lun;
	__be32 itt;
	__be32 ttt;
	u32 rsvd2;
	u32 exp_stat_sn;
	u32 rsvd3;
	__be32 data_sn;
	__be32 buffer_offset;
	u32 rsvd4;
} __packed;

struct iscsi_data_in_hdr {
	u8  opcode;
	u8  flags;
	u8  rsvd1;
	u8  cmd_status;
	u8  ahslength;
	u8  datalength[3];
	u32 rsvd2[2];
	__be32 itt;
	__be32 ttt;
	u32 stat_sn;
	u32 exp_cmd_sn;
	u32 max_cmd_sn;
	__be32 data_sn;
	__be32 buffer_offset;
	__be32 residual_count;
} __packed;

#define ISCSI_FLG_STATUS		0x01

struct iscsi_r2t_hdr {
	u8  opcode;
	u8  flags;
	u16 rsvd1;
	u8  ahslength;
	u8  datalength[3];
	__be64 lun;
	__be32 itt;
	__be32 ttt;
	u32 stat_sn;
	u32 exp_cmd_sn;
	u32 max_cmd_sn;
	u32 r2t_sn;
	__be32 buffer_offset;
	__be32 data_length;
} __packed;

struct iscsi_async_msg_hdr {
	u8  opcode;
	u8  flags;
	u16 rsvd1;
	u8  ahslength;
	u8  datalength[3];
	__be64 lun;
	__be32 ffffffff;
	u32 rsvd2;
	u32 stat_sn;
	u32 exp_cmd_sn;
	u32 max_cmd_sn;
	u8  async_event;
	u8  async_vcode;
	__be16 param1;
	__be16 param2;
	__be16 param3;
	u32 rsvd3;
} __packed;

#define ISCSI_ASYNC_SCSI		0
#define ISCSI_ASYNC_LOGOUT		1
#define ISCSI_ASYNC_DROP_CONNECTION	2
#define ISCSI_ASYNC_DROP_SESSION	3
#define ISCSI_ASYNC_PARAM_REQUEST	4
#define ISCSI_ASYNC_VENDOR		255

struct iscsi_text_req_hdr {
	u8  opcode;
	u8  flags;
	u16 rsvd1;
	u8  ahslength;
	u8  datalength[3];
	u32 rsvd2[2];
	__be32 itt;
	__be32 ttt;
	u32 cmd_sn;
	u32 exp_stat_sn;
	u32 rsvd3[4];
} __packed;

struct iscsi_text_rsp_hdr {
	u8  opcode;
	u8  flags;
	u16 rsvd1;
	u8  ahslength;
	u8  datalength[3];
	u32 rsvd2[2];
	__be32 itt;
	__be32 ttt;
	u32 stat_sn;
	u32 exp_cmd_sn;
	u32 max_cmd_sn;
	u32 rsvd3[3];
} __packed;

struct iscsi_login_req_hdr {
	u8  opcode;
	u8  flags;
	u8  max_version;		/* Max. version supported */
	u8  min_version;		/* Min. version supported */
	u8  ahslength;
	u8  datalength[3];
	union iscsi_sid sid;
	__be32 itt;			/* Initiator Task Tag */
	__be16 cid;			/* Connection ID */
	u16 rsvd1;
	u32 cmd_sn;
	u32 exp_stat_sn;
	u32 rsvd2[4];
} __packed;

struct iscsi_login_rsp_hdr {
	u8  opcode;
	u8  flags;
	u8  max_version;		/* Max. version supported */
	u8  active_version;		/* Active version */
	u8  ahslength;
	u8  datalength[3];
	union iscsi_sid sid;
	__be32 itt;			/* Initiator Task Tag */
	u32 rsvd1;
	u32 stat_sn;
	u32 exp_cmd_sn;
	u32 max_cmd_sn;
	u8  status_class;		/* see Login RSP Status classes below */
	u8  status_detail;		/* see Login RSP Status details below */
	u8  rsvd2[10];
} __packed;

#define ISCSI_FLG_FINAL			0x80
#define ISCSI_FLG_TRANSIT		0x80
#define ISCSI_FLG_CSG_SECURITY		0x00
#define ISCSI_FLG_CSG_LOGIN		0x04
#define ISCSI_FLG_CSG_FULL_FEATURE	0x0c
#define ISCSI_FLG_CSG_MASK		0x0c
#define ISCSI_FLG_NSG_SECURITY		0x00
#define ISCSI_FLG_NSG_LOGIN		0x01
#define ISCSI_FLG_NSG_FULL_FEATURE	0x03
#define ISCSI_FLG_NSG_MASK		0x03

/* Login Status response classes */
#define ISCSI_STATUS_SUCCESS		0x00
#define ISCSI_STATUS_REDIRECT		0x01
#define ISCSI_STATUS_INITIATOR_ERR	0x02
#define ISCSI_STATUS_TARGET_ERR		0x03

/* Login Status response detail codes */
/* Class-0 (Success) */
#define ISCSI_STATUS_ACCEPT		0x00

/* Class-1 (Redirection) */
#define ISCSI_STATUS_TGT_MOVED_TEMP	0x01
#define ISCSI_STATUS_TGT_MOVED_PERM	0x02

/* Class-2 (Initiator Error) */
#define ISCSI_STATUS_INIT_ERR		0x00
#define ISCSI_STATUS_AUTH_FAILED	0x01
#define ISCSI_STATUS_TGT_FORBIDDEN	0x02
#define ISCSI_STATUS_TGT_NOT_FOUND	0x03
#define ISCSI_STATUS_TGT_REMOVED	0x04
#define ISCSI_STATUS_NO_VERSION		0x05
#define ISCSI_STATUS_TOO_MANY_CONN	0x06
#define ISCSI_STATUS_MISSING_FIELDS	0x07
#define ISCSI_STATUS_CONN_ADD_FAILED	0x08
#define ISCSI_STATUS_INV_SESSION_TYPE	0x09
#define ISCSI_STATUS_SESSION_NOT_FOUND	0x0a
#define ISCSI_STATUS_INV_REQ_TYPE	0x0b

/* Class-3 (Target Error) */
#define ISCSI_STATUS_TARGET_ERROR	0x00
#define ISCSI_STATUS_SVC_UNAVAILABLE	0x01
#define ISCSI_STATUS_NO_RESOURCES	0x02

struct iscsi_logout_req_hdr {
	u8  opcode;
	u8  flags;
	u16 rsvd1;
	u8  ahslength;
	u8  datalength[3];
	u32 rsvd2[2];
	__be32 itt;
	__be16 cid;
	u16 rsvd3;
	u32 cmd_sn;
	u32 exp_stat_sn;
	u32 rsvd4[4];
} __packed;

struct iscsi_logout_rsp_hdr {
	u8  opcode;
	u8  flags;
	u8  response;
	u8  rsvd1;
	u8  ahslength;
	u8  datalength[3];
	u32 rsvd2[2];
	__be32 itt;
	u32 rsvd3;
	u32 stat_sn;
	u32 exp_cmd_sn;
	u32 max_cmd_sn;
	u32 rsvd4;
	__be16 time2wait;
	__be16 time2retain;
	u32 rsvd5;
} __packed;

struct iscsi_snack_req_hdr {
	u8  opcode;
	u8  flags;
	u16 rsvd1;
	u8  ahslength;
	u8  datalength[3];
	u32 rsvd2[2];
	__be32 itt;
	__be32 ttt;
	u32 rsvd3;
	u32 exp_stat_sn;
	u32 rsvd4[2];
	__be32 beg_run;
	__be32 run_length;
} __packed;

struct iscsi_reject_hdr {
	u8  opcode;
	u8  flags;
	u8  reason;
	u8  rsvd1;
	u8  ahslength;
	u8  datalength[3];
	u32 rsvd2[2];
	__be32 ffffffff;
	__be32 rsvd3;
	u32 stat_sn;
	u32 exp_cmd_sn;
	u32 max_cmd_sn;
	__be32 data_sn;
	u32 rsvd4[2];
} __packed;

#define ISCSI_REASON_RESERVED			0x01
#define ISCSI_REASON_DATA_DIGEST_ERROR		0x02
#define ISCSI_REASON_DATA_SNACK_REJECT		0x03
#define ISCSI_REASON_PROTOCOL_ERROR		0x04
#define ISCSI_REASON_UNSUPPORTED_COMMAND	0x05
#define ISCSI_REASON_IMMEDIATE_COMMAND_REJECT	0x06
#define ISCSI_REASON_TASK_IN_PROGRESS		0x07
#define ISCSI_REASON_INVALID_DATA_ACK		0x08
#define ISCSI_REASON_INVALID_PDU_FIELD		0x09
#define ISCSI_REASON_OUT_OF_RESOURCES		0x0a
#define ISCSI_REASON_NEGOTIATION_RESET		0x0b
#define ISCSI_REASON_WAITING_LOGOUT		0x0c

struct iscsi_nop_out_hdr {
	u8  opcode;
	u8  flags;
	u16 rsvd1;
	u8  ahslength;
	u8  datalength[3];
	__be64 lun;
	__be32 itt;
	__be32 ttt;
	u32 cmd_sn;
	u32 exp_stat_sn;
	u32 rsvd2[4];
} __packed;

struct iscsi_nop_in_hdr {
	u8  opcode;
	u8  flags;
	u16 rsvd1;
	u8  ahslength;
	u8  datalength[3];
	__be64 lun;
	__be32 itt;
	__be32 ttt;
	u32 stat_sn;
	u32 exp_cmd_sn;
	u32 max_cmd_sn;
	u32 rsvd2[3];
} __packed;

#define ISCSI_RESERVED_TAG_CPU32 (0xffffffffU)
#define ISCSI_RESERVED_TAG (cpu_to_be32(ISCSI_RESERVED_TAG_CPU32))

#define cmnd_hdr(cmnd) ((struct iscsi_scsi_cmd_hdr *) (&((cmnd)->pdu.bhs)))
#define cmnd_opcode(cmnd) ((cmnd)->pdu.bhs.opcode & ISCSI_OPCODE_MASK)
#define cmnd_scsicode(cmnd) (cmnd_hdr((cmnd))->scb[0])

#endif	/* __ISCSI_HDR_H__ */