/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 *
 * dspRead.c 
 *
 * From v01.17 08/22/90 mbs
 *    Modified for MP, 1996 by Tuyen Nguyen
 *   Modified, April 9, 1997 by Tuyen Nguyen for MacOSX.
 */

#include <sys/errno.h>
#include <sys/types.h>
#include <sys/param.h>
#include <machine/spl.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/filedesc.h>
#include <sys/fcntl.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>

#include <netat/sysglue.h>
#include <netat/appletalk.h>
#include <netat/at_pcb.h>
#include <netat/debug.h>
#include <netat/adsp.h>
#include <netat/adsp_internal.h>

/*
 * CheckReadQueue
 *
 * Checks to see if there is any data in the receive queue.  If there
 * is data, a pb and the data are queued to the user.
 * 
 *      
 */
extern int adsp_check;

int CheckReadQueue(sp)          /* (CCBPtr sp) */
    register CCBPtr sp;
{
    register struct adspcmd *pb;
    int s;
    unsigned short cnt;
    char eom = 0;
    register gbuf_t *mp;
    register gbuf_t *tmp;
    gref_t *gref;
        
    dPrintf(D_M_ADSP, D_L_TRACE, ("CheckReadQueue: sp=0x%x\n", (unsigned)sp));
    KERNEL_DEBUG(DBG_ADSP_READ, 0, sp, sp->rbuf_mb, sp->rpb, sp->delay);
    trace_mbufs(D_M_ADSP_LOW, "    bCQR m", sp->rbuf_mb);
    ATDISABLE(s, sp->lock);

    while (sp->rData && (pb = sp->rpb)) {               /* have data */
        dPrintf(D_M_ADSP, D_L_TRACE, 
                 (" pb=0x%x, gref=0x%x, ioc=0x%x, reqCount=%d (have data)\n", 
                  pb, pb->gref, pb->ioc, pb->u.ioParams.reqCount));
        KERNEL_DEBUG(DBG_ADSP_READ, 1, pb, pb->gref, pb->ioc, pb->u.ioParams.reqCount);
        if (pb->u.ioParams.reqCount == 0) {
            pb->ioResult = 0;
            sp->rpb = pb->qLink;
            if (pb->ioc) {
                KERNEL_DEBUG(DBG_ADSP_READ, 2, pb, pb->gref, pb->ioc, 0); 
                adspioc_ack(0, pb->ioc, pb->gref);
            } else {
                KERNEL_DEBUG(DBG_ADSP_READ, 3, pb, pb->gref, 0, 0);
                completepb(sp, pb);
            }
            continue;
        }
            
        /* take the first packet off of sp->rbuf_mb or sp->crbuf_mb */
        if (mp = sp->rbuf_mb) { /* Get header for oldest data */
            KERNEL_DEBUG(DBG_ADSP_READ, 4, pb, mp, gbuf_msgsize(mp), gbuf_next(mp));
            sp->rbuf_mb = gbuf_next(mp);
            gbuf_next(mp) = 0;
            eom = 1;
        } else if (mp = sp->crbuf_mb) {
            KERNEL_DEBUG(DBG_ADSP_READ, 5, pb, mp, gbuf_msgsize(mp), gbuf_next(mp));
            sp->crbuf_mb = 0;
            eom = 0;
        }

        /* Get the first (reqCount-actCount) bytes and tack them onto 
           the end of pb->mp.  If eom is set, put the remainder of the 
           data onto the front of sp->rbuf_mb, otherwise sp->crbuf_mb. */
        cnt = gbuf_msgsize(mp); /* # of data bytes in it. */
        if (cnt > (unsigned short)(pb->u.ioParams.reqCount - pb->u.ioParams.actCount)) {
            cnt = pb->u.ioParams.reqCount - pb->u.ioParams.actCount;
            /* m_split returns the tail */
            if (!(tmp = (gbuf_t *)m_split(mp, cnt, M_DONTWAIT))) {
                cnt = 0;
                tmp = mp;
            }
            if (eom) {
                gbuf_next(tmp) = sp->rbuf_mb;
                sp->rbuf_mb = tmp;
                eom = 0;
            } else
                sp->crbuf_mb = tmp;     
        }
        if (cnt) {
            pb->u.ioParams.actCount += cnt;
            gbuf_linkb(pb->mp, mp);
        }

        pb->u.ioParams.eom = eom;
        /*
         * Now clean up receive buffer to remove all of the data 
         * we just copied
         */
        if ((sp->rbuf_mb == 0) && 
            (sp->crbuf_mb == 0)) /* no more data blocks */
            sp->rData = 0;
        /*
         * If we've filled the parameter block, unlink it from read 
         * queue and complete it. We also need to do this if the connection
         * is closed && there is no more stuff to read.
         */
        if (eom || (pb->u.ioParams.actCount >= pb->u.ioParams.reqCount) ||
            ((sp->state == sClosed) && (!sp->rData)) ) {
              /* end of message, message is full, connection
               * is closed and all data has been delivered,
               * or we are not to "delay" data delivery.
               */
            pb->ioResult = 0;
            sp->rpb = pb->qLink; /* dequeue request */
            if (pb->ioc) {      /* data to be delivered at the time of the */
                mp = gbuf_cont(pb->mp); /* ioctl call */
                gbuf_cont(pb->mp) = 0;
                gref = (gref_t *)pb->gref;
                adspioc_ack(0, pb->ioc, pb->gref);
                dPrintf(D_M_ADSP, D_L_TRACE, ("    (pb->ioc) mp=%x\n", mp));
                KERNEL_DEBUG(DBG_ADSP_READ, 0x0A, pb,  mp, 
                             gbuf_next(mp), gbuf_cont(mp));
                SndMsgUp(gref, mp);
                dPrintf(D_M_ADSP, D_L_TRACE, 
                        ("    (data) size req=%d\n", pb->u.ioParams.actCount));
                KERNEL_DEBUG(DBG_ADSP_READ, 0x0B, pb, pb->ioc, 
                             pb->u.ioParams.reqCount, pb->u.ioParams.actCount);
            } else {            /* complete an queued async request */
                KERNEL_DEBUG(DBG_ADSP_READ, 0x0C, pb, sp, 
                             pb->u.ioParams.actCount, sp->delay);
                completepb(sp, pb);
            }
        }
    }   /* while */

    if (pb = sp->rpb) {         /* if there is an outstanding request */
        dPrintf(D_M_ADSP, D_L_TRACE, 
                 (" pb=0x%x, ioc=0x%x, reqCount=%d (no more data)\n", 
                  pb, pb->ioc, pb->u.ioParams.reqCount));
        KERNEL_DEBUG(DBG_ADSP_READ, 0x0D, pb, pb->ioc, 
                     pb->u.ioParams.reqCount, pb->u.ioParams.actCount);

        if (sp->state == sClosed) {
            while (pb) {
                    KERNEL_DEBUG(DBG_ADSP_READ, 0x0E, pb, sp, pb->ioc, 0);
                    pb->ioResult = 0;
                    pb->u.ioParams.actCount = 0;
                    pb->u.ioParams.eom = 0;
                    sp->rpb = pb->qLink;
                    if (pb->ioc) {
                            adspioc_ack(0, pb->ioc, pb->gref);
                    } else {
                            completepb(sp, pb);
                    }
                    pb = sp->rpb;
            }
        } else if (pb->ioc) {   /* if request not complete and this
                                 * is an active ioctl, release user */
            sp->rpb = pb->qLink;
            pb->ioResult = 1;
            tmp = gbuf_cont(pb->mp); /* detatch perhaps delayed data */
            gbuf_cont(pb->mp) = 0;
            if (mp = gbuf_copym(pb->mp)) { /* otherwise, duplicate user request */
                    KERNEL_DEBUG(DBG_ADSP_READ, 0x0F, pb, sp, pb->mp, 0);
                    adspioc_ack(0, pb->ioc, pb->gref);  /* release user */
                    pb = (struct adspcmd *)gbuf_rptr(mp); /* get new parameter block */
                    pb->ioc = 0;
                    pb->mp = mp;
                    gbuf_cont(pb->mp) = tmp; /* reattach data */
                    pb->qLink = sp->rpb; /* requeue the duplicate at the head */
                    sp->rpb = pb;
            } else {            /* there is no data left, but no space
                                 * to duplicate the parameter block, so
                                 * put what must be a non EOM message 
                                 * back on the current receive queue, and
                                 * error out the user
                                 */
                    KERNEL_DEBUG(DBG_ADSP_READ, 0x10, pb, sp, pb->mp, 0);
                    if (tmp) {
                            sp->crbuf_mb = tmp;
                            sp->rData = 1;
                    }
                    pb->ioResult = errDSPQueueSize;
                    adspioc_ack(ENOBUFS, pb->ioc, pb->gref);
            }
        } 
    }
    /* 
     * The receive window has opened.  If was previously closed, then we
     * need to notify the other guy that we now have room to receive more
     * data.  But, in order to cut down on lots of small data packets,
     * we'll wait until the recieve buffer  is /14 empy before telling
     * him that there's room in our receive buffer.
     */
    if (sp->rbufFull && (CalcRecvWdw(sp) > (sp->rbuflen >> 2))) {
        sp->rbufFull = 0;
        sp->sendDataAck = 1;
        sp->callSend = 1;
    }
    ATENABLE(s, sp->lock);

    KERNEL_DEBUG(DBG_ADSP_READ, 0x11, sp, 0, 0, 0);
    trace_mbufs(D_M_ADSP_LOW, "    eCQR m", sp->rbuf_mb);
    return 0;
}

/*
 * CheckAttn
 *
 * Checks to see if there is any attention data and passes the data back
 * in the passed in pb.
 * 
 * INPUTS:
 *      sp
 *      pb
 *      
 * OUTPUTS:
 *      
 */
int CheckAttn(sp, pb)           /* (CCBPtr sp) */
    register CCBPtr sp;
    register struct adspcmd *pb;
{
    int s;
    gbuf_t *mp;
    gref_t *gref;
        
    dPrintf(D_M_ADSP, D_L_TRACE, 
            ("CheckAttn: sp=0x%x, pb=0x%x\n", (unsigned)sp, (unsigned)pb));

    ATDISABLE(s, sp->lock);
    if (mp = sp->attn_mb) {

        /*
         * Deliver the attention data to the user. 
         */
        gref = (gref_t *)pb->gref;
        pb->u.attnParams.attnSize = sp->attnSize;
        pb->u.attnParams.attnCode = sp->attnCode;
        if (!sp->attnSize) {
            gbuf_freem(mp);
            mp = 0;
        }
        sp->userFlags &= ~eAttention;
        /*
         * Now clean up receive buffer to remove all of the data 
         * we just copied
         */
        sp->attn_mb = 0;
        pb->ioResult = 0;
    } else {
        /*
         * No data...
         */
        pb->u.attnParams.attnSize = 0;
        pb->u.attnParams.attnCode = 0;
        pb->ioResult = 1;       /* not done */
    }
    adspioc_ack(0, pb->ioc, pb->gref);
    if (mp) {
        SndMsgUp(gref, mp);
        }
    ATENABLE(s, sp->lock);
    return 0;
}

/*
 * adspRead
 * 
 * INPUTS:
 *      --> sp                  stream pointer
 *      --> pb                  user request parameter block
 *
 * OUTPUTS:
 *      <-- actCount            actual number of bytes read
 *      <-- eom                 one if end-of-message, zero otherwise
 *
 * ERRORS:
 *      errRefNum               bad connection refnum
 *      errState
 *      errFwdReset             read terminated by forward reset
 *      errAborted              request aborted by Remove or Close call
 */
int adspRead(sp, pb)            /* (DSPPBPtr pb) */
    register CCBPtr sp;
    register struct adspcmd *pb;
{
    register gbuf_t *mp;
    int s;

    dPrintf(D_M_ADSP, D_L_TRACE, 
            ("adspRead: sp=0x%x, pb=0x%x\n", (unsigned)sp, (unsigned)pb));

    KERNEL_DEBUG(DBG_ADSP_READ, 0x12, sp, pb, sp->state, sp->rData); 

    if (sp == 0) {
        pb->ioResult = errRefNum;
        return EINVAL;
    }
        
    /*
     * It's OK to read on a closed, or closing session
     */
    ATDISABLE(s, sp->lock);
    if (sp->state != sOpen && sp->state != sClosing && sp->state != sClosed) {
        ATENABLE(s, sp->lock);
        pb->ioResult = errState;
        return EINVAL;
    }
    if (sp->rData && (sp->rpb == 0)) { /* if data, and no queue of pbs */
        qAddToEnd(&sp->rpb, pb); /* deliver data to user directly */
        ATENABLE(s, sp->lock);
        CheckReadQueue(sp);
    } else if ((pb->u.ioParams.reqCount == 0) && (sp->rpb == 0)) {
            /* empty read */
            ATENABLE(s, sp->lock);
            pb->ioResult = 0;
            adspioc_ack(0, pb->ioc, pb->gref);
            return 0;
    } else {
        pb->ioResult = 1;
        if (mp = gbuf_copym(pb->mp)) { /* otherwise, duplicate user request */
                adspioc_ack(0, pb->ioc, pb->gref);      /* release user */
                pb = (struct adspcmd *)gbuf_rptr(mp);   /* get new parameter block */
                pb->ioc = 0;
                pb->mp = mp;
                qAddToEnd(&sp->rpb, pb); /* and queue it for later */
                ATENABLE(s, sp->lock);
        } else {
                ATENABLE(s, sp->lock);
                pb->ioResult = errDSPQueueSize;
                return ENOBUFS;
        }
    }

    if (sp->callSend) {
        CheckSend(sp);          /* If recv window opened, we might */
                                /* send an unsolicited ACK. */
    }
    return 0;
}

/*
 * dspReadAttention
 * 
 * INPUTS:
 *      --> sp                  stream pointer
 *      --> pb                  user request parameter block
 *
 * OUTPUTS:
 *      <-- NONE
 *
 * ERRORS:
 *      errRefNum               bad connection refnum
 *      errState                connection is not in the right state
 */
int adspReadAttention(sp, pb)           /* (DSPPBPtr pb) */
    register CCBPtr sp;
    register struct adspcmd *pb;
{
    dPrintf(D_M_ADSP, D_L_TRACE, 
            ("adspReadAttention: sp=0x%x, pb=0x%x\n", (unsigned)sp, (unsigned)pb));
    if (sp == 0) {
        pb->ioResult = errRefNum;
        return EINVAL;
    }
        
    /*
     * It's OK to read on a closed, or closing session
     */
    if (sp->state != sOpen && sp->state != sClosing && sp->state != sClosed) {
        pb->ioResult = errState;
        return EINVAL;
    }

    CheckAttn(sp, pb);          /* Anything in the attention queue */
    CheckReadQueue(sp);         /* check to see if receive window has opened */
    if (sp->callSend) {
        CheckSend(sp);          /* If recv window opened, we might */
                                /* send an unsolicited ACK. */
        }
    return 0;
} /* adspReadAttention */