/*
   * iSCSI lib definitions
   *
   * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
   * Copyright (C) 2004 - 2006 Mike Christie
   * Copyright (C) 2004 - 2005 Dmitry Yusupov
   * Copyright (C) 2004 - 2005 Alex Aizman
   *
   * 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; either version 2 of the License, or
   * (at your option) any later version.
   *
   * 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.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   */
  #ifndef LIBISCSI_H
  #define LIBISCSI_H
  
  #include <linux/types.h>

  #include <linux/wait.h>

  #include <linux/mutex.h>

  #include <linux/timer.h>
  #include <linux/workqueue.h>

  #include <linux/kfifo.h>

  #include <linux/refcount.h>

  #include <scsi/iscsi_proto.h>
  #include <scsi/iscsi_if.h>

  #include <scsi/scsi_transport_iscsi.h>

  
  struct scsi_transport_template;

  struct scsi_host_template;

  struct scsi_device;
  struct Scsi_Host;

  struct scsi_target;

  struct scsi_cmnd;
  struct socket;
  struct iscsi_transport;
  struct iscsi_cls_session;
  struct iscsi_cls_conn;
  struct iscsi_session;
  struct iscsi_nopin;

  struct device;

  #define ISCSI_DEF_XMIT_CMDS_MAX	128	/* must be power of 2 */

  #define ISCSI_MGMT_CMDS_MAX	15

  #define ISCSI_DEF_CMD_PER_LUN	32

  
  /* Task Mgmt states */

  enum {
  	TMF_INITIAL,
  	TMF_QUEUED,
  	TMF_SUCCESS,
  	TMF_FAILED,
  	TMF_TIMEDOUT,
  	TMF_NOT_FOUND,
  };

  #define ISID_SIZE			6

  /* Connection suspend "bit" */
  #define ISCSI_SUSPEND_BIT		1

  #define ISCSI_ITT_MASK			0x1fff

  #define ISCSI_TOTAL_CMDS_MAX		4096
  /* this must be a power of two greater than ISCSI_MGMT_CMDS_MAX */
  #define ISCSI_TOTAL_CMDS_MIN		16

  #define ISCSI_AGE_SHIFT			28

  #define ISCSI_AGE_MASK			0xf

  #define ISCSI_ADDRESS_BUF_LEN		64

  enum {

  	/* this is the maximum possible storage for AHSs */
  	ISCSI_MAX_AHS_SIZE = sizeof(struct iscsi_ecdb_ahdr) +
  				sizeof(struct iscsi_rlength_ahdr),

  	ISCSI_DIGEST_SIZE = sizeof(__u32),
  };

  enum {

  	ISCSI_TASK_FREE,

  	ISCSI_TASK_COMPLETED,
  	ISCSI_TASK_PENDING,
  	ISCSI_TASK_RUNNING,

  	ISCSI_TASK_ABRT_TMF,		/* aborted due to TMF */
  	ISCSI_TASK_ABRT_SESS_RECOV,	/* aborted due to session recovery */

  	ISCSI_TASK_REQUEUE_SCSIQ,	/* qcmd requeueing to scsi-ml */

  };

  struct iscsi_r2t_info {
  	__be32			ttt;		/* copied from R2T */
  	__be32			exp_statsn;	/* copied from R2T */
  	uint32_t		data_length;	/* copied from R2T */
  	uint32_t		data_offset;	/* copied from R2T */
  	int			data_count;	/* DATA-Out payload progress */
  	int			datasn;
  	/* LLDs should set/update these values */
  	int			sent;		/* R2T sequence progress */
  };

  struct iscsi_task {

  	/*

  	 * Because LLDs allocate their hdr differently, this is a pointer
  	 * and length to that storage. It must be setup at session
  	 * creation time.

  	 */

  	struct iscsi_hdr	*hdr;

  	unsigned short		hdr_max;
  	unsigned short		hdr_len;	/* accumulated size of hdr used */

  	/* copied values in case we need to send tmfs */
  	itt_t			hdr_itt;
  	__be32			cmdsn;

  	struct scsi_lun		lun;

  	int			itt;		/* this ITT */

  	unsigned		imm_count;	/* imm-data (bytes)   */

  	/* offset in unsolicited stream (bytes); */

  	struct iscsi_r2t_info	unsol_r2t;

  	char			*data;		/* mgmt payload */

  	unsigned		data_count;

  	struct scsi_cmnd	*sc;		/* associated SCSI cmd*/

  	struct iscsi_conn	*conn;		/* used connection    */

  	/* data processing tracking */
  	unsigned long		last_xfer;
  	unsigned long		last_timeout;
  	bool			have_checked_conn;

  
  	/* T10 protection information */
  	bool			protected;

  	/* state set/tested under session->lock */
  	int			state;

  	refcount_t		refcount;

  	struct list_head	running;	/* running cmd list */
  	void			*dd_data;	/* driver/transport data */
  };

  static inline int iscsi_task_has_unsol_data(struct iscsi_task *task)
  {
  	return task->unsol_r2t.data_length > task->unsol_r2t.sent;
  }

  static inline void* iscsi_next_hdr(struct iscsi_task *task)

  {

  	return (void*)task->hdr + task->hdr_len;

  }

  /* Connection's states */
  enum {
  	ISCSI_CONN_INITIAL_STAGE,
  	ISCSI_CONN_STARTED,
  	ISCSI_CONN_STOPPED,
  	ISCSI_CONN_CLEANUP_WAIT,
  };

  struct iscsi_conn {
  	struct iscsi_cls_conn	*cls_conn;	/* ptr to class connection */
  	void			*dd_data;	/* iscsi_transport data */
  	struct iscsi_session	*session;	/* parent session */
  	/*

  	 * conn_stop() flag: stop to recover, stop to terminate
  	 */
          int			stop_stage;

  	struct timer_list	transport_timer;
  	unsigned long		last_recv;
  	unsigned long		last_ping;
  	int			ping_timeout;
  	int			recv_timeout;

  	struct iscsi_task 	*ping_task;

  
  	/* iSCSI connection-wide sequencing */
  	uint32_t		exp_statsn;

  	uint32_t		statsn;

  
  	/* control data */
  	int			id;		/* CID */

  	int			c_stage;	/* connection state */

  	/*
  	 * Preallocated buffer for pdus that have data but do not
  	 * originate from scsi-ml. We never have two pdus using the
  	 * buffer at the same time. It is only allocated to
  	 * the default max recv size because the pdus we support
  	 * should always fit in this buffer
  	 */
  	char			*data;

  	struct iscsi_task 	*login_task;	/* mtask used for login/text */
  	struct iscsi_task	*task;		/* xmit task in progress */

  
  	/* xmit */

  	spinlock_t		taskqueuelock;  /* protects the next three lists */

  	struct list_head	mgmtqueue;	/* mgmt (control) xmit queue */

  	struct list_head	cmdqueue;	/* data-path cmd queue */

  	struct list_head	requeue;	/* tasks needing another run */

  	struct work_struct	xmitwork;	/* per-conn. xmit workqueue */

  	unsigned long		suspend_tx;	/* suspend Tx */
  	unsigned long		suspend_rx;	/* suspend Rx */
  
  	/* abort */
  	wait_queue_head_t	ehwait;		/* used in eh_abort() */
  	struct iscsi_tm		tmhdr;

  	struct timer_list	tmf_timer;
  	int			tmf_state;	/* see TMF_INITIAL, etc.*/

  
  	/* negotiated params */

  	unsigned		max_recv_dlength; /* initiator_max_recv_dsl*/
  	unsigned		max_xmit_dlength; /* target_max_recv_dsl */

  	int			hdrdgst_en;
  	int			datadgst_en;

  	int			ifmarker_en;
  	int			ofmarker_en;
  	/* values userspace uses to id a conn */
  	int			persistent_port;
  	char			*persistent_address;

  	unsigned		max_segment_size;
  	unsigned		tcp_xmit_wsf;
  	unsigned		tcp_recv_wsf;
  	uint16_t		keepalive_tmo;
  	uint16_t		local_port;
  	uint8_t			tcp_timestamp_stat;
  	uint8_t			tcp_nagle_disable;
  	uint8_t			tcp_wsf_disable;
  	uint8_t			tcp_timer_scale;
  	uint8_t			tcp_timestamp_en;
  	uint8_t			fragment_disable;
  	uint8_t			ipv4_tos;
  	uint8_t			ipv6_traffic_class;
  	uint8_t			ipv6_flow_label;
  	uint8_t			is_fw_assigned_ipv6;

  	char			*local_ipaddr;

  	/* MIB-statistics */
  	uint64_t		txdata_octets;
  	uint64_t		rxdata_octets;
  	uint32_t		scsicmd_pdus_cnt;
  	uint32_t		dataout_pdus_cnt;
  	uint32_t		scsirsp_pdus_cnt;
  	uint32_t		datain_pdus_cnt;
  	uint32_t		r2t_pdus_cnt;
  	uint32_t		tmfcmd_pdus_cnt;
  	int32_t			tmfrsp_pdus_cnt;
  
  	/* custom statistics */
  	uint32_t		eh_abort_cnt;

  	uint32_t		fmr_unalign_cnt;

  };

  struct iscsi_pool {

  	struct kfifo		queue;		/* FIFO Queue */

  	void			**pool;		/* Pool of elements */
  	int			max;		/* Max number of elements */
  };

  /* Session's states */
  enum {
  	ISCSI_STATE_FREE = 1,
  	ISCSI_STATE_LOGGED_IN,
  	ISCSI_STATE_FAILED,
  	ISCSI_STATE_TERMINATE,
  	ISCSI_STATE_IN_RECOVERY,
  	ISCSI_STATE_RECOVERY_FAILED,
  	ISCSI_STATE_LOGGING_OUT,
  };

  struct iscsi_session {

  	struct iscsi_cls_session *cls_session;

  	/*
  	 * Syncs up the scsi eh thread with the iscsi eh thread when sending
  	 * task management functions. This must be taken before the session
  	 * and recv lock.
  	 */
  	struct mutex		eh_mutex;

  	/* iSCSI session-wide sequencing */
  	uint32_t		cmdsn;
  	uint32_t		exp_cmdsn;
  	uint32_t		max_cmdsn;

  	/* This tracks the reqs queued into the initiator */
  	uint32_t		queued_cmdsn;

  	/* configuration */

  	int			abort_timeout;
  	int			lu_reset_timeout;

  	int			tgt_reset_timeout;

  	int			initial_r2t_en;

  	unsigned short		max_r2t;

  	int			imm_data_en;

  	unsigned		first_burst;
  	unsigned		max_burst;

  	int			time2wait;
  	int			time2retain;
  	int			pdu_inorder_en;
  	int			dataseq_inorder_en;
  	int			erl;

  	int			fast_abort;

  	int			tpgt;

  	char			*username;
  	char			*username_in;
  	char			*password;
  	char			*password_in;

  	char			*targetname;

  	char			*targetalias;

  	char			*ifacename;
  	char			*initiatorname;

  	char			*boot_root;
  	char			*boot_nic;
  	char			*boot_target;

  	char			*portal_type;
  	char			*discovery_parent_type;
  	uint16_t		discovery_parent_idx;
  	uint16_t		def_taskmgmt_tmo;
  	uint16_t		tsid;
  	uint8_t			auto_snd_tgt_disable;
  	uint8_t			discovery_sess;
  	uint8_t			chap_auth_en;
  	uint8_t			discovery_logout_en;
  	uint8_t			bidi_chap_en;
  	uint8_t			discovery_auth_optional;
  	uint8_t			isid[ISID_SIZE];

  	/* control data */
  	struct iscsi_transport	*tt;
  	struct Scsi_Host	*host;
  	struct iscsi_conn	*leadconn;	/* leading connection */

  	/* Between the forward and the backward locks exists a strict locking
  	 * hierarchy. The mutual exclusion zone protected by the forward lock
  	 * can enclose the mutual exclusion zone protected by the backward lock
  	 * but not vice versa.
  	 */
  	spinlock_t		frwd_lock;	/* protects session state, *
  						 * cmdsn, queued_cmdsn     *

  						 * session resources:      *

  						 * - cmdpool kfifo_out ,   *
  						 * - mgmtpool,		   */
  	spinlock_t		back_lock;	/* protects cmdsn_exp      *
  						 * cmdsn_max,              *
  						 * cmdpool kfifo_in        */

  	int			state;		/* session state           */

  	int			age;		/* counts session re-opens */

  	int			scsi_cmds_max; 	/* max scsi commands */

  	int			cmds_max;	/* size of cmds array */

  	struct iscsi_task	**cmds;		/* Original Cmds arr */

  	struct iscsi_pool	cmdpool;	/* PDU's pool */

  	void			*dd_data;	/* LLD private data */

  };

  enum {
  	ISCSI_HOST_SETUP,
  	ISCSI_HOST_REMOVED,
  };

  struct iscsi_host {
  	char			*initiatorname;
  	/* hw address or netdev iscsi connection is bound to */
  	char			*hwaddress;
  	char			*netdev;

  
  	wait_queue_head_t	session_removal_wq;
  	/* protects sessions and state */
  	spinlock_t		lock;
  	int			num_sessions;
  	int			state;

  
  	struct workqueue_struct	*workq;
  	char			workq_name[20];

  };

  /*
   * scsi host template
   */

  extern int iscsi_eh_abort(struct scsi_cmnd *sc);

  extern int iscsi_eh_recover_target(struct scsi_cmnd *sc);
  extern int iscsi_eh_session_reset(struct scsi_cmnd *sc);

  extern int iscsi_eh_device_reset(struct scsi_cmnd *sc);

  extern int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc);

  extern enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc);

  /*
   * iSCSI host helpers.
   */

  #define iscsi_host_priv(_shost) \
  	(shost_priv(_shost) + sizeof(struct iscsi_host))

  extern int iscsi_host_set_param(struct Scsi_Host *shost,
  				enum iscsi_host_param param, char *buf,
  				int buflen);
  extern int iscsi_host_get_param(struct Scsi_Host *shost,
  				enum iscsi_host_param param, char *buf);

  extern int iscsi_host_add(struct Scsi_Host *shost, struct device *pdev);
  extern struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,

  					  int dd_data_size,

  					  bool xmit_can_sleep);

  extern void iscsi_host_remove(struct Scsi_Host *shost);
  extern void iscsi_host_free(struct Scsi_Host *shost);

  extern int iscsi_target_alloc(struct scsi_target *starget);

  
  /*
   * session management
   */
  extern struct iscsi_cls_session *

  iscsi_session_setup(struct iscsi_transport *, struct Scsi_Host *shost,

  		    uint16_t, int, int, uint32_t, unsigned int);

  extern void iscsi_session_teardown(struct iscsi_cls_session *);

  extern void iscsi_session_recovery_timedout(struct iscsi_cls_session *);

  extern int iscsi_set_param(struct iscsi_cls_conn *cls_conn,
  			   enum iscsi_param param, char *buf, int buflen);
  extern int iscsi_session_get_param(struct iscsi_cls_session *cls_session,
  				   enum iscsi_param param, char *buf);

  #define iscsi_session_printk(prefix, _sess, fmt, a...)	\

  	iscsi_cls_session_printk(prefix, _sess->cls_session, fmt, ##a)

  /*
   * connection management
   */
  extern struct iscsi_cls_conn *iscsi_conn_setup(struct iscsi_cls_session *,

  					       int, uint32_t);

  extern void iscsi_conn_teardown(struct iscsi_cls_conn *);
  extern int iscsi_conn_start(struct iscsi_cls_conn *);
  extern void iscsi_conn_stop(struct iscsi_cls_conn *, int);
  extern int iscsi_conn_bind(struct iscsi_cls_session *, struct iscsi_cls_conn *,
  			   int);
  extern void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err);

  extern void iscsi_session_failure(struct iscsi_session *session,

  				  enum iscsi_err err);

  extern int iscsi_conn_get_param(struct iscsi_cls_conn *cls_conn,
  				enum iscsi_param param, char *buf);

  extern int iscsi_conn_get_addr_param(struct sockaddr_storage *addr,
  				     enum iscsi_param param, char *buf);

  extern void iscsi_suspend_tx(struct iscsi_conn *conn);

  extern void iscsi_suspend_queue(struct iscsi_conn *conn);

  extern void iscsi_conn_queue_work(struct iscsi_conn *conn);

  #define iscsi_conn_printk(prefix, _c, fmt, a...) \

  	iscsi_cls_conn_printk(prefix, ((struct iscsi_conn *)_c)->cls_conn, \
  			      fmt, ##a)

  /*
   * pdu and task processing
   */

  extern void iscsi_update_cmdsn(struct iscsi_session *, struct iscsi_nopin *);

  extern void iscsi_prep_data_out_pdu(struct iscsi_task *task,
  				    struct iscsi_r2t_info *r2t,
  				    struct iscsi_data *hdr);

  extern int iscsi_conn_send_pdu(struct iscsi_cls_conn *, struct iscsi_hdr *,
  				char *, uint32_t);
  extern int iscsi_complete_pdu(struct iscsi_conn *, struct iscsi_hdr *,
  			      char *, int);

  extern int __iscsi_complete_pdu(struct iscsi_conn *, struct iscsi_hdr *,
  				char *, int);

  extern int iscsi_verify_itt(struct iscsi_conn *, itt_t);

  extern struct iscsi_task *iscsi_itt_to_ctask(struct iscsi_conn *, itt_t);

  extern struct iscsi_task *iscsi_itt_to_task(struct iscsi_conn *, itt_t);

  extern void iscsi_requeue_task(struct iscsi_task *task);
  extern void iscsi_put_task(struct iscsi_task *task);

  extern void __iscsi_put_task(struct iscsi_task *task);

  extern void __iscsi_get_task(struct iscsi_task *task);

  extern void iscsi_complete_scsi_task(struct iscsi_task *task,
  				     uint32_t exp_cmdsn, uint32_t max_cmdsn);

  
  /*
   * generic helpers
   */

  extern void iscsi_pool_free(struct iscsi_pool *);
  extern int iscsi_pool_init(struct iscsi_pool *, int, void ***, int);

  extern int iscsi_switch_str_param(char **, char *);

  /*
   * inline functions to deal with padding.
   */
  static inline unsigned int
  iscsi_padded(unsigned int len)
  {
  	return (len + ISCSI_PAD_LEN - 1) & ~(ISCSI_PAD_LEN - 1);
  }
  
  static inline unsigned int
  iscsi_padding(unsigned int len)
  {
  	len &= (ISCSI_PAD_LEN - 1);
  	if (len)
  		len = ISCSI_PAD_LEN - len;
  	return len;
  }

  #endif