/*
 * 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 2003 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef _SYS_LOGINDMUX_IMPL_H
#define _SYS_LOGINDMUX_IMPL_H

#include <sys/types.h>
#include <sys/stream.h>

#ifdef  __cplusplus
extern "C" {
#endif


/*
 * This structure is shared between two logindmux peer instances and
 * ensures that only one of the peers will be actively processing an
 * I_UNLINK ioctl at any one time.
 */
typedef struct unlinkinfo {
        kmutex_t        state_lock;     /* serialize access to state */
        int             state;          /* state of I_UNLINK operation */
        mblk_t          *prot_mp;       /* carries protocol messages */
} unlinkinfo_t;

/*
 * Logindmux state structure; one per open instance.
 */
struct tmx {
        queue_t         *rdq;           /* our mux upper read queue */
        queue_t         *muxq;          /* our mux lower write queue */
        queue_t         *peerq;         /* peer mux lower write queue */
        minor_t         dev0;           /* our minor device number */
        boolean_t       isptm;          /* true if ptm is downstream */
        mblk_t          *unlink_mp;     /* mblk used in logdmux_unlink_timer */
        unlinkinfo_t    *unlinkinfop;   /* used during I_UNLINK processing */
        bufcall_id_t    wbufcid;        /* needed for recovery */
        bufcall_id_t    rbufcid;        /* needed for recovery */
        timeout_id_t    utimoutid;      /* unlink timer identifier */
        timeout_id_t    wtimoutid;      /* needed for recovery */
        timeout_id_t    rtimoutid;      /* needed for recovery */
};

#define LOGDMX_ID               107     /* module id number */

/*
 * The arguments for calls to qtimeout, in microseconds.
 */
#define SIMWAIT                 100000  /* logdmux_timer */
#define LOGDMUX_POLL_WAIT       10      /* logdmux_unlink_timer */

/*
 * State of peer linkage.
 */
enum {
        LOGDMUX_LINKED          = 1,    /* peer instances are in linked state */
        LOGDMUX_UNLINK_PENDING  = 2,    /* a peer is actively I_UNLINKing */
        LOGDMUX_UNLINKED        = 3     /* a peer has completed its I_UNLINK */
};

/*
 * Protocol message magic cookie.
 */
#define LOGDMUX_MCTL            (LOGDMX_ID << 16)

/*
 * peer to peer protocol messages.
 */
#define LOGDMUX_UNLINK_REQ      (LOGDMUX_MCTL|1) /* peer wants to unlink */
#define LOGDMUX_UNLINK_RESP     (LOGDMUX_MCTL|2) /* ok for peer to unlink */

/*
 * Macro to determine if an mblk is a logindmux protocol mblk.
 */
#define LOGDMUX_PROTO_MBLK(mp)                                             \
        ((DB_TYPE(mp) == M_CTL)                                         && \
        ((mp)->b_cont != NULL)                                          && \
        (DB_TYPE((mp)->b_cont) == M_IOCTL)                              && \
        (((struct iocblk *)((mp)->b_cont->b_rptr))->ioc_cmd == I_UNLINK))


#ifdef  __cplusplus
}
#endif

#endif  /* _SYS_LOGINDMUX_IMPL_H */