xref: /illumos-gate/usr/src/uts/common/sys/stream.h (revision ff550d0e264b51131fb34e9e83163b348d916640)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
/*	  All Rights Reserved  	*/


#ifndef _SYS_STREAM_H
#define	_SYS_STREAM_H

#pragma ident	"%Z%%M%	%I%	%E% SMI"	/* SVr4.0 11.44	*/

/*
 * For source compatibility
 */
#include <sys/isa_defs.h>
#include <sys/vnode.h>
#include <sys/poll.h>
#include <sys/strmdep.h>
#include <sys/cred.h>
#include <sys/t_lock.h>
#include <sys/model.h>
#include <sys/strft.h>

#ifdef	__cplusplus
extern "C" {
#endif

/*
 * Both the queue and the data block structures have embedded
 * mutexes: q_lock and db_lock.  In general, these mutexes protect
 * the consistency of the data structure.  In addition, q_lock
 * is used, with the stream head condition variable, to implement
 * a monitor at the stream head for blocking reads and writes.
 * Neither of these locks should be acquired by module or driver code.
 *
 * In particular, q_lock protects the following fields:
 *	q_first
 *	q_last
 *	q_link
 *	q_count
 *	q_bandp
 *	q_nband
 *
 * q_next is protected by stream head locking; this links the
 * stream together, and should be thought of as part of the stream
 * data structure, not the queue.
 *
 * The remaining fields are either modified only by the allocator,
 * which has exclusive access to them at that time, or are not to
 * be touched by anything but the MT synchronization primitives
 * (i.e. q_wait).
 *
 * q_sqnext and q_sqprev are special - they are protected by
 * SQLOCK(q->syncq).
 */

/*
 * Data queue
 */
typedef struct	queue {
	struct	qinit	*q_qinfo;	/* procs and limits for queue	*/
	struct	msgb	*q_first;	/* first data block		*/
	struct	msgb	*q_last;	/* last data block		*/
	struct	queue	*q_next;	/* Q of next stream		*/
	struct	queue	*q_link;	/* to next Q for scheduling	*/
	void		*q_ptr;		/* to private data structure	*/
	size_t		q_count;	/* number of bytes on Q		*/
	uint_t		q_flag;		/* queue state			*/
	ssize_t		q_minpsz;	/* min packet size accepted by	*/
					/* this module			*/
	ssize_t		q_maxpsz;	/* max packet size accepted by	*/
					/* this module			*/
	size_t		q_hiwat;	/* queue high water mark	*/
	size_t		q_lowat;	/* queue low water mark		*/
	struct qband	*q_bandp;	/* separate flow information */
	kmutex_t	q_lock;		/* protect data queue		*/
	struct stdata 	*q_stream;	/* for head locks		*/
	struct	syncq	*q_syncq;	/* sync queue object		*/
	unsigned char	q_nband;	/* number of priority bands > 0	*/
	kcondvar_t	q_wait;		/* read/write sleeps		*/
	struct	queue	*q_nfsrv;	/* next q fwd with service routine */
	ushort_t	q_draining;	/* protected by QLOCK - drain_syncq */
	short		q_struiot;	/* stream uio type for struio()	*/
	uint_t		q_syncqmsgs;	/* messages in syncq for this queue */
	size_t		q_mblkcnt;	/* mblk counter for runaway msgs */
	/*
	 * Syncq scheduling.
	 * These fields are initially protected by the SQLOCK,
	 * but they will eventually be protected by the QLOCK.
	 * The lock ordering is QLOCK then SQLOCK.
	 * Note that  q_syncqmsgs can either disappear, or be an additional
	 * count of messages instead of bytes (need bytes for QFULL).
	 */
	struct msgb	*q_sqhead;	/* first syncq message		*/
	struct msgb	*q_sqtail;	/* last syncq message		*/
	uint_t		q_sqflags;	/* Queue flags, protected by SQLOCK */
	size_t		q_rwcnt;	/* Number of threads synchronously */
					/* entering Q */

	/*
	 * These fields need to be protected by the SQLOCK since
	 * the corresponding syncq fields are (sq_head/sq_tail).
	 */
	struct queue	*q_sqnext;	/* Next Q on syncq list		*/
	struct queue	*q_sqprev;	/* Previous Q on syncq list	*/
	clock_t		q_sqtstamp;	/* Time when Q was scheduled for sq */
	clock_t		q_qtstamp;	/* Time when Q was enabled	*/
	pri_t		q_spri;		/* Scheduling priority		*/

	/*
	 * Reference to the queue's module's implementation structure. This
	 * will be NULL for queues associated with drivers.
	 */
	struct fmodsw_impl	*q_fp;
} queue_t;

/*
 * Queue flags; unused flags not documented in queue(9S) can be recycled.
 */
#define	QENAB		0x00000001	/* Queue is already enabled to run */
#define	QWANTR		0x00000002	/* Someone wants to read Q	*/
#define	QWANTW		0x00000004	/* Someone wants to write Q	*/
#define	QFULL		0x00000008	/* Q is considered full		*/
#define	QREADR		0x00000010	/* This is the reader (first) Q	*/
#define	QUSE		0x00000020	/* This queue in use (allocation) */
#define	QNOENB		0x00000040	/* Don't enable Q via putq	*/
#define	QWANTRMQSYNC	0x00000080	/* Want to remove sync stream Q */
#define	QBACK		0x00000100	/* queue has been back-enabled	*/
/*	UNUSED		0x00000200	   was QHLIST			*/
/* 	UNUSED 		0x00000400	   was QUNSAFE			*/
#define	QPAIR		0x00000800	/* per queue-pair syncq		*/
#define	QPERQ 		0x00001000	/* per queue-instance syncq	*/
#define	QPERMOD		0x00002000	/* per module syncq		*/
#define	QMTSAFE		0x00004000	/* stream module is MT-safe	*/
#define	QMTOUTPERIM	0x00008000	/* Has outer perimeter		*/
#define	QMT_TYPEMASK	(QPAIR|QPERQ|QPERMOD|QMTSAFE|QMTOUTPERIM)
					/* all MT type flags		*/
#define	QINSERVICE	0x00010000	/* service routine executing	*/
#define	QWCLOSE		0x00020000	/* will not be enabled		*/
#define	QEND		0x00040000	/* last queue in stream		*/
#define	QWANTWSYNC	0x00080000	/* Streamhead wants to write Q	*/
#define	QSYNCSTR	0x00100000	/* Q supports Synchronous STREAMS */
#define	QISDRV		0x00200000	/* the Queue is attached to a driver */
/*	UNUSED		0x00400000	   was QHOT			*/
/*	UNUSED		0x00800000	   was QNEXTHOT			*/
/* 	UNUSED		0x01000000	   was _QNEXTLESS		*/
#define	_QINSERTING	0x04000000	/* Private, module is being inserted */
#define	_QREMOVING	0x08000000	/* Private, module is being removed */
#define	_QASSOCIATED	0x10000000	/* queue is associated with a device */
#define	_QDIRECT	0x20000000	/* Private; transport module uses */
					/* direct interface to/from sockfs */

/* queue sqflags (protected by SQLOCK). */
#define	Q_SQQUEUED	0x01		/* Queue is in the syncq list */
#define	Q_SQDRAINING	0x02		/* Servicing suncq msgs.	*/
					/* This is also noted by the	*/
					/* q_draining field, but this one is */
					/* protected by SQLOCK */

/*
 * Structure that describes the separate information
 * for each priority band in the queue.
 */
typedef struct qband {
	struct qband	*qb_next;	/* next band's info */
	size_t		qb_count;	/* number of bytes in band */
	struct msgb	*qb_first;	/* beginning of band's data */
	struct msgb	*qb_last;	/* end of band's data */
	size_t		qb_hiwat;	/* high water mark for band */
	size_t		qb_lowat;	/* low water mark for band */
	uint_t		qb_flag;	/* see below */
	size_t		qb_mblkcnt;	/* mblk counter for runaway msgs */
} qband_t;

/*
 * qband flags
 */
#define	QB_FULL		0x01		/* band is considered full */
#define	QB_WANTW	0x02		/* Someone wants to write to band */
#define	QB_BACK		0x04		/* queue has been back-enabled */

/*
 * Maximum number of bands.
 */
#define	NBAND	256

/*
 * Fields that can be manipulated through strqset() and strqget().
 */
typedef enum qfields {
	QHIWAT	= 0,		/* q_hiwat or qb_hiwat */
	QLOWAT	= 1,		/* q_lowat or qb_lowat */
	QMAXPSZ	= 2,		/* q_maxpsz */
	QMINPSZ	= 3,		/* q_minpsz */
	QCOUNT	= 4,		/* q_count or qb_count */
	QFIRST	= 5,		/* q_first or qb_first */
	QLAST	= 6,		/* q_last or qb_last */
	QFLAG	= 7,		/* q_flag or qb_flag */
	QSTRUIOT = 8,		/* q_struiot */
	QBAD	= 9
} qfields_t;

/*
 * Module information structure
 */
struct module_info {
	ushort_t mi_idnum;		/* module id number */
	char 	*mi_idname;		/* module name */
	ssize_t	mi_minpsz;		/* min packet size accepted */
	ssize_t	mi_maxpsz;		/* max packet size accepted */
	size_t	mi_hiwat;		/* hi-water mark */
	size_t 	mi_lowat;		/* lo-water mark */
};

/*
 * queue information structure (with Synchronous STREAMS extensions)
 */
struct	qinit {
	int	(*qi_putp)();		/* put procedure */
	int	(*qi_srvp)();		/* service procedure */
	int	(*qi_qopen)();		/* called on startup */
	int	(*qi_qclose)();		/* called on finish */
	int	(*qi_qadmin)();		/* for future use */
	struct module_info *qi_minfo;	/* module information structure */
	struct module_stat *qi_mstat;	/* module statistics structure */
	int	(*qi_rwp)();		/* r/w procedure */
	int	(*qi_infop)();		/* information procedure */
	int	qi_struiot;		/* stream uio type for struio() */
};

/*
 * Values for qi_struiot and q_struiot:
 */
#define	STRUIOT_NONE		-1	/* doesn't support struio() */
#define	STRUIOT_DONTCARE	0	/* use current uiomove() (default) */
#define	STRUIOT_STANDARD	1	/* use standard uiomove() */

/*
 * Streamtab (used in cdevsw and fmodsw to point to module or driver)
 */
struct streamtab {
	struct qinit *st_rdinit;
	struct qinit *st_wrinit;
	struct qinit *st_muxrinit;
	struct qinit *st_muxwinit;
};

/*
 * Structure sent to mux drivers to indicate a link.
 */
struct linkblk {
	queue_t *l_qtop;	/* lowest level write queue of upper stream */
				/* (set to NULL for persistent links) */
	queue_t *l_qbot;	/* highest level write queue of lower stream */
	int	l_index;	/* index for lower stream. */
};

/*
 * Esballoc data buffer freeing routine
 */
typedef struct free_rtn {
	void	(*free_func)();
	caddr_t	free_arg;
} frtn_t;

/*
 * Data block descriptor
 *
 * NOTE: db_base, db_lim, db_ref and db_type are the *only* public fields,
 * as described in datab(9S).  Everything else is implementation-private.
 */

#define	DBLK_REFMAX	255U

typedef struct datab {
	frtn_t		*db_frtnp;
	unsigned char	*db_base;
	unsigned char	*db_lim;
	unsigned char	db_ref;
	unsigned char	db_type;
	unsigned char	db_flags;
	unsigned char	db_struioflag;
	pid_t		db_cpid;	/* cached pid, needs verification */
	void		*db_cache;	/* kmem cache descriptor */
	struct msgb	*db_mblk;
	void		(*db_free)(struct msgb *, struct datab *);
	void		(*db_lastfree)(struct msgb *, struct datab *);
	intptr_t	db_cksumstart;
	intptr_t	db_cksumend;
	intptr_t	db_cksumstuff;
	union {
		double enforce_alignment;
		unsigned char data[8];
		struct {
			union {
				uint32_t u32;
				uint16_t u16;
			} cksum_val;    /* used to store calculated cksum */
			uint16_t flags;
			uint16_t pad;
		} cksum;
		/*
		 * Union used for future extensions (pointer to data ?).
		 */
	} db_struioun;
	fthdr_t		*db_fthdr;
	cred_t		*db_credp;	/* credential */
} dblk_t;

#define	db_cksum16	db_struioun.cksum.cksum_val.u16
#define	db_cksum32	db_struioun.cksum.cksum_val.u32

/*
 * Accessor macros for private dblk_t fields (the rest are in <sys/strsun.h>).
 */
#define	DB_CPID(mp)		((mp)->b_datap->db_cpid)
#define	DB_CRED(mp)		((mp)->b_datap->db_credp)
#define	DB_CREDDEF(mp, cr)	(DB_CRED(mp) != NULL ? DB_CRED(mp) : (cr))
#define	DB_FTHDR(mp)		((mp)->b_datap->db_fthdr)

/*
 * Message block descriptor
 */
typedef struct	msgb {
	struct	msgb	*b_next;
	struct  msgb	*b_prev;
	struct	msgb	*b_cont;
	unsigned char	*b_rptr;
	unsigned char	*b_wptr;
	struct datab 	*b_datap;
	unsigned char	b_band;
	unsigned char	b_tag;
	unsigned short	b_flag;
	queue_t		*b_queue;	/* for sync queues */
} mblk_t;

/*
 * bcache descriptor
 */

typedef	struct	bcache {
	kmutex_t		mutex;
	struct kmem_cache	*buffer_cache;
	struct kmem_cache	*dblk_cache;
	int			alloc;
	int			destroy;
	size_t			size;
	uint_t			align;
} bcache_t;

/*
 * db_flags values (all implementation private!)
 */
#define	DBLK_REFMIN	0x01		/* min refcnt stored in low bit */

/*
 * db_struioflag values:
 */
#define	STRUIO_SPEC	0x01	/* struio{get,put}() special mblk */
#define	STRUIO_DONE	0x02	/* struio done (could be partial) */
#define	STRUIO_IP	0x04	/* IP checksum stored in db_struioun */
#define	STRUIO_ZC	0x08	/* mblk eligible for zero-copy */
#define	STRUIO_ZCNOTIFY	0x10	/* notify stream head when mblk acked */
#define	STRUIO_EAGER	0x20	/* new eager; db_cksumstart has squeue to use */
#define	STRUIO_POLICY	0x40	/* new eager when IPsec is enabled */

/*
 * Message flags.  These are interpreted by the stream head.
 */
#define	MSGMARK		0x01	/* last byte of message is "marked" */
#define	MSGNOLOOP	0x02	/* don't loop message around to */
				/* write side of stream */
#define	MSGDELIM	0x04	/* message is delimited */
/*	UNUSED		0x08	   was MSGNOGET (can be recycled) */
#define	MSGMARKNEXT	0x10	/* Private: first byte of next msg marked */
#define	MSGNOTMARKNEXT	0x20	/* Private: ... not marked */
#define	MSGHASREF	0x40	/* Private: message has reference to owner */

/*
 * Streams message types.
 */

/*
 * Data and protocol messages (regular and priority)
 */
#define	M_DATA		0x00		/* regular data */
#define	M_PROTO		0x01		/* protocol control */
#define	M_MULTIDATA	0x02		/* reserved for Multidata use only */

/*
 * Control messages (regular and priority)
 */
#define	M_BREAK		0x08		/* line break */
#define	M_PASSFP	0x09		/* pass file pointer */
#define	M_EVENT		0x0a		/* Obsoleted: do not use */
#define	M_SIG		0x0b		/* generate process signal */
#define	M_DELAY		0x0c		/* real-time xmit delay (1 param) */
#define	M_CTL		0x0d		/* device-specific control message */
#define	M_IOCTL		0x0e		/* ioctl; set/get params */
#define	M_SETOPTS	0x10		/* set various stream head options */
#define	M_RSE		0x11		/* reserved for RSE use only */

/*
 * Control messages (high priority; go to head of queue)
 */
#define	M_IOCACK	0x81		/* acknowledge ioctl */
#define	M_IOCNAK	0x82		/* negative ioctl acknowledge */
#define	M_PCPROTO	0x83		/* priority proto message */
#define	M_PCSIG		0x84		/* generate process signal */
#define	M_READ		0x85		/* generate read notification */
#define	M_FLUSH		0x86		/* flush your queues */
#define	M_STOP		0x87		/* stop transmission immediately */
#define	M_START		0x88		/* restart transmission after stop */
#define	M_HANGUP	0x89		/* line disconnect */
#define	M_ERROR		0x8a		/* send error to stream head */
#define	M_COPYIN	0x8b		/* request to copyin data */
#define	M_COPYOUT	0x8c		/* request to copyout data */
#define	M_IOCDATA	0x8d		/* response to M_COPYIN and M_COPYOUT */
#define	M_PCRSE		0x8e		/* reserved for RSE use only */
#define	M_STOPI		0x8f		/* stop reception immediately */
#define	M_STARTI	0x90		/* restart reception after stop */
#define	M_PCEVENT	0x91		/* Obsoleted: do not use */
#define	M_UNHANGUP	0x92		/* line reconnect, sigh */

/*
 * Queue message class definitions.
 */
#define	QNORM		0x00		/* normal priority messages */
#define	QPCTL		0x80		/* high priority cntrl messages */

/*
 *  IOCTL structure - this structure is the format of the M_IOCTL message type.
 */
#if	defined(_LP64)
struct iocblk {
	int 	ioc_cmd;		/* ioctl command type */
	cred_t	*ioc_cr;		/* full credentials */
	uint_t	ioc_id;			/* ioctl id */
	uint_t	ioc_flag;		/* see below */
	size_t	ioc_count;		/* count of bytes in data field */
	int	ioc_rval;		/* return value  */
	int	ioc_error;		/* error code */
};
#else
struct iocblk {
	int 	ioc_cmd;		/* ioctl command type */
	cred_t	*ioc_cr;		/* full credentials */
	uint_t	ioc_id;			/* ioctl id */
	size_t	ioc_count;		/* count of bytes in data field */
	int	ioc_error;		/* error code */
	int	ioc_rval;		/* return value  */
	int	ioc_fill1;
	uint_t	ioc_flag;		/* see below */
	int	ioc_filler[2];		/* reserved for future use */
};
#endif	/* _LP64 */

typedef	struct iocblk	*IOCP;

/* {ioc,cp}_flags values */

#define	IOC_MODELS	DATAMODEL_MASK	/* Note: 0x0FF00000 */
#define	IOC_ILP32	DATAMODEL_ILP32	/* ioctl origin is ILP32 */
#define	IOC_LP64	DATAMODEL_LP64	/* ioctl origin is LP64 */
#define	IOC_NATIVE	DATAMODEL_NATIVE
#define	IOC_NONE	DATAMODEL_NONE	/* dummy comparison value */

/*
 *	Is the ioctl data formatted for our native model?
 */
#define	IOC_CONVERT_FROM(iocp)	ddi_model_convert_from( \
				    ((struct iocblk *)iocp)->ioc_flag)

/*
 * structure for the M_COPYIN and M_COPYOUT message types.
 */
#if	defined(_LP64)
struct copyreq {
	int	cq_cmd;			/* ioctl command (from ioc_cmd) */
	cred_t	*cq_cr;			/* full credentials (from ioc_cmd) */
	uint_t	cq_id;			/* ioctl id (from ioc_id) */
	uint_t	cq_flag;		/* must be zero */
	mblk_t	*cq_private;		/* private state information */
	caddr_t	cq_addr;		/* address to copy data to/from */
	size_t	cq_size;		/* number of bytes to copy */
};
#else
struct copyreq {
	int	cq_cmd;			/* ioctl command (from ioc_cmd) */
	cred_t	*cq_cr;			/* full credentials */
	uint_t	cq_id;			/* ioctl id (from ioc_id) */
	caddr_t	cq_addr;		/* address to copy data to/from */
	size_t	cq_size;		/* number of bytes to copy */
	uint_t	cq_flag;		/* must be zero */
	mblk_t	*cq_private;		/* private state information */
	int	cq_filler[4];		/* reserved for future use */
};
#endif	/* _LP64 */

/*
 * structure for the M_IOCDATA message type.
 */
#if	defined(_LP64)
struct copyresp {
	int	cp_cmd;			/* ioctl command (from ioc_cmd) */
	cred_t	*cp_cr;			/* full credentials (from ioc_cmd) */
	uint_t	cp_id;			/* ioctl id (from ioc_id) */
	uint_t	cp_flag;		/* datamodel IOC_ flags; see above */
	mblk_t *cp_private;		/* private state information */
	caddr_t	cp_rval;		/* status of request: 0 -> success */
					/* 		non-zero -> failure */
};
#else
struct copyresp {
	int	cp_cmd;			/* ioctl command (from ioc_cmd) */
	cred_t	*cp_cr;			/* full credentials */
	uint_t	cp_id;			/* ioctl id (from ioc_id) */
	caddr_t	cp_rval;		/* status of request: 0 -> success */
					/* 		non-zero -> failure */
	size_t	cp_pad1;
	uint_t	cp_pad2;
	mblk_t *cp_private;		/* private state information */
	uint_t	cp_flag;		/* datamodel IOC_ flags; see above */
	int	cp_filler[3];
};
#endif	/* _LP64 */

/*
 * Since these structures are all intended to travel in the same message
 * at different stages of a STREAMS ioctl, this union is used to determine
 * the message size in strdoioctl().
 */
union ioctypes {
	struct iocblk	iocblk;
	struct copyreq	copyreq;
	struct copyresp	copyresp;
};

/*
 * Options structure for M_SETOPTS message.  This is sent upstream
 * by a module or driver to set stream head options.
 */

struct stroptions {
	uint_t	so_flags;		/* options to set */
	short	so_readopt;		/* read option */
	ushort_t so_wroff;		/* write offset */
	ssize_t	so_minpsz;		/* minimum read packet size */
	ssize_t	so_maxpsz;		/* maximum read packet size */
	size_t	so_hiwat;		/* read queue high water mark */
	size_t	so_lowat;		/* read queue low water mark */
	unsigned char so_band;		/* band for water marks */
	ushort_t so_erropt;		/* error option */
	ssize_t	so_maxblk;		/* maximum message block size */
	ushort_t so_copyopt;		/* copy options (see stropts.h) */
};

/* flags for stream options set message */

#define	SO_ALL		0x003f	/* set all old options */
#define	SO_READOPT	0x0001	/* set read option */
#define	SO_WROFF	0x0002	/* set write offset */
#define	SO_MINPSZ	0x0004	/* set min packet size */
#define	SO_MAXPSZ	0x0008	/* set max packet size */
#define	SO_HIWAT	0x0010	/* set high water mark */
#define	SO_LOWAT	0x0020	/* set low water mark */
#define	SO_MREADON	0x0040	/* set read notification ON */
#define	SO_MREADOFF	0x0080	/* set read notification OFF */
#define	SO_NDELON	0x0100	/* old TTY semantics for NDELAY reads/writes */
#define	SO_NDELOFF	0x0200	/* STREAMS semantics for NDELAY reads/writes */
#define	SO_ISTTY	0x0400	/* the stream is acting as a terminal */
#define	SO_ISNTTY	0x0800	/* the stream is not acting as a terminal */
#define	SO_TOSTOP	0x1000	/* stop on background writes to this stream */
#define	SO_TONSTOP	0x2000	/* do not stop on background writes to stream */
#define	SO_BAND		0x4000	/* water marks affect band */
#define	SO_DELIM	0x8000	/* messages are delimited */
#define	SO_NODELIM	0x010000	/* turn off delimiters */
#define	SO_STRHOLD	0x020000	/* No longer implemented */
#define	SO_ERROPT	0x040000	/* set error option */
#define	SO_COPYOPT	0x080000	/* copy option(s) present */
#define	SO_MAXBLK	0x100000	/* set maximum message block size */

#ifdef _KERNEL
/*
 * Structure for rw (read/write) procedure calls. A pointer
 * to a struiod_t is passed as a parameter to the rwnext() call.
 *
 * Note: DEF_IOV_MAX is defined and used as it is in "fs/vncalls.c"
 *	 as there isn't a formal definition of IOV_MAX ???
 */
#define	DEF_IOV_MAX	16

typedef struct struiod {
	mblk_t		*d_mp;		/* pointer to mblk (chain) */
	uio_t		d_uio;		/* uio info */
	iovec_t d_iov[DEF_IOV_MAX];	/* iov referenced by uio */
} struiod_t;

/*
 * Structure for information procedure calls.
 */
typedef struct infod {
	unsigned char	d_cmd;		/* info info request command */
	unsigned char	d_res;		/* info info command results */
	int		d_bytes;	/* mblk(s) byte count */
	int		d_count;	/* count of mblk(s) */
	uio_t		*d_uiop;	/* pointer to uio struct */
} infod_t;
/*
 * Values for d_cmd & d_res.
 */
#define	INFOD_FIRSTBYTES	0x02	/* return msgbsize() of first mblk */
#define	INFOD_BYTES		0x04	/* return msgbsize() of all mblk(s) */
#define	INFOD_COUNT		0x08	/* return count of mblk(s) */
#define	INFOD_COPYOUT		0x10	/* copyout any M_DATA mblk(s) */

#endif /* _KERNEL */

/*
 * Miscellaneous parameters and flags.
 */

/*
 * Values for stream flag in open to indicate module open, clone open,
 * and the return value for failure.
 */
#define	MODOPEN 	0x1		/* open as a module */
#define	CLONEOPEN	0x2		/* clone open; pick own minor dev */
#define	OPENFAIL	-1		/* returned for open failure */

/*
 * Priority definitions for block allocation.
 */
#define	BPRI_LO		1
#define	BPRI_MED	2
#define	BPRI_HI		3

/*
 * Value for packet size that denotes infinity
 */
#define	INFPSZ		-1

/*
 * Flags for flushq()
 */
#define	FLUSHALL	1	/* flush all messages */
#define	FLUSHDATA	0	/* don't flush control messages */

/*
 * Flag for transparent ioctls
 */
#define	TRANSPARENT	(unsigned int)(-1)

/*
 * Stream head default high/low water marks
 */
#define	STRHIGH 5120
#define	STRLOW	1024

/*
 * Block allocation parameters
 */
#define	MAXIOCBSZ	1024		/* max ioctl data block size */

/*
 * qwriter perimeter types
 */
#define	PERIM_INNER	1		/* The inner perimeter */
#define	PERIM_OUTER	2		/* The outer perimeter */

/*
 * Definitions of Streams macros and function interfaces.
 */

/*
 * canenable - check if queue can be enabled by putq().
 */
#define	canenable(q)	!((q)->q_flag & QNOENB)

/*
 * Test if data block type is one of the data messages (i.e. not a control
 * message).
 */
#define	datamsg(type) \
		((type) == M_DATA || \
		    (type) == M_MULTIDATA || \
		    (type) == M_PROTO || \
		    (type) == M_PCPROTO || \
		    (type) == M_DELAY)

/*
 * Extract queue class of message block.
 */
#define	queclass(bp) (((bp)->b_datap->db_type >= QPCTL) ? QPCTL : QNORM)

/*
 * Align address on next lower word boundary.
 */
#define	straln(a)	(caddr_t)((intptr_t)(a) & -(sizeof (int)-1))

/*
 * Find the max size of data block.
 */
#define	bpsize(bp) ((unsigned int)(bp->b_datap->db_lim - bp->b_datap->db_base))

#ifdef _KERNEL

/*
 * For two-byte M_ERROR messages: indication that a side does not have an error
 */
#define	NOERROR	((unsigned char)-1)

/*
 * declarations of common routines
 */

extern mblk_t *allocb(size_t, uint_t);
extern mblk_t *desballoc(unsigned char *, size_t, uint_t, frtn_t *);
extern mblk_t *esballoc(unsigned char *, size_t, uint_t, frtn_t *);
extern bcache_t *bcache_create(char *, size_t, uint_t);
extern void bcache_destroy(bcache_t *);
extern mblk_t *bcache_allocb(bcache_t *, uint_t);
extern mblk_t *mkiocb(uint_t);
extern int testb(size_t, uint_t);
extern bufcall_id_t bufcall(size_t, uint_t, void (*)(void *), void *);
extern bufcall_id_t esbbcall(uint_t, void (*)(void *), void *);
extern void freeb(struct msgb *);
extern void freemsg(mblk_t *);
extern mblk_t *dupb(mblk_t *);
extern mblk_t *dupmsg(mblk_t *);
extern mblk_t *dupmsg_noloan(mblk_t *);
extern mblk_t *copyb(mblk_t *);
extern mblk_t *copymsg(mblk_t *);
extern void linkb(mblk_t *, mblk_t *);
extern mblk_t *unlinkb(mblk_t *);
extern mblk_t *reallocb(mblk_t *, size_t, uint_t);	/* private */
extern mblk_t *rmvb(mblk_t *, mblk_t *);
extern int pullupmsg(struct msgb *, ssize_t);
extern mblk_t *msgpullup(struct msgb *, ssize_t);
extern int adjmsg(struct msgb *, ssize_t);
extern size_t msgdsize(struct msgb *);
extern mblk_t *getq(queue_t *);
extern void rmvq(queue_t *, mblk_t *);
extern void flushq(queue_t *, int);
extern void flushq_common(queue_t *, int, int);
extern void flushband(queue_t *, unsigned char, int);
extern int canput(queue_t *);
extern int bcanput(queue_t *, unsigned char);
extern int canputnext(queue_t *);
extern int bcanputnext(queue_t *, unsigned char);
extern int putq(queue_t *, mblk_t *);
extern int putbq(queue_t *, mblk_t *);
extern int insq(queue_t *, mblk_t *, mblk_t *);
extern void put(queue_t *, mblk_t *);
extern void putnext(queue_t *, mblk_t *);
extern int putctl(queue_t *, int);
extern int putctl1(queue_t *, int, int);
extern int putnextctl(queue_t *, int);
extern int putnextctl1(queue_t *, int, int);
extern queue_t *backq(queue_t *);
extern void qreply(queue_t *, mblk_t *);
extern void qenable(queue_t *);
extern int qsize(queue_t *);
extern void noenable(queue_t *);
extern void enableok(queue_t *);
extern int strqset(queue_t *, qfields_t, unsigned char, intptr_t);
extern int strqget(queue_t *, qfields_t, unsigned char, void *);
extern void unbufcall(bufcall_id_t);
extern void qprocson(queue_t *);
extern void qprocsoff(queue_t *);
extern void freezestr(queue_t *);
extern void unfreezestr(queue_t *);
extern void qwait(queue_t *);
extern int qwait_sig(queue_t *);
extern boolean_t qwait_rw(queue_t *);
extern void qwriter(queue_t *, mblk_t *, void (*func)(), int);
extern timeout_id_t qtimeout(queue_t *, void (*func)(void *), void *, clock_t);
extern bufcall_id_t qbufcall(queue_t *, size_t, uint_t,
    void (*)(void *), void *);
extern clock_t quntimeout(queue_t *, timeout_id_t);
extern void qunbufcall(queue_t *, bufcall_id_t);
extern void strwakeq(queue_t *, int);
extern int struioget(queue_t *, mblk_t *, struiod_t *, int);
extern int rwnext(queue_t *, struiod_t *);
extern int infonext(queue_t *, infod_t *);
extern int isuioq(queue_t *);
extern void create_putlocks(queue_t *, int);

/*
 * shared or externally configured data structures
 */
extern int nstrpush;			/* maximum number of pushes allowed */

#endif /* _KERNEL */

#ifdef	__cplusplus
}
#endif

#endif	/* _SYS_STREAM_H */