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

/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * t_snd.c and t_sndv.c are very similar and contain common code.
 * Any changes to either of them should be reviewed to see whether they
 * are applicable to the other file.
 */
#include "mt.h"
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <stropts.h>
#include <sys/stream.h>
#define _SUN_TPI_VERSION 2
#include <sys/tihdr.h>
#include <sys/timod.h>
#include <xti.h>
#include <syslog.h>
#include "tx.h"


int
_tx_snd(int fd, char *buf, unsigned nbytes, int flags, int api_semantics)
{
        struct T_data_req datareq;
        struct strbuf ctlbuf, databuf;
        unsigned int bytes_sent, bytes_remaining, bytes_to_send;
        char *curptr;
        struct _ti_user *tiptr;
        int band;
        int retval, lookevent;
        int sv_errno;
        int doputmsg = 0;
        int32_t tsdu_limit;

        if ((tiptr = _t_checkfd(fd, 0, api_semantics)) == NULL)
                return (-1);
        sig_mutex_lock(&tiptr->ti_lock);

        if (tiptr->ti_servtype == T_CLTS) {
                t_errno = TNOTSUPPORT;
                sig_mutex_unlock(&tiptr->ti_lock);
                return (-1);
        }

        if (_T_IS_XTI(api_semantics)) {
                /*
                 * User level state verification only done for XTI
                 * because doing for TLI may break existing applications
                 */
                if (! (tiptr->ti_state == T_DATAXFER ||
                    tiptr->ti_state == T_INREL)) {
                        t_errno = TOUTSTATE;
                        sig_mutex_unlock(&tiptr->ti_lock);
                        return (-1);
                }
                /*
                 * XXX
                 * Is it OK to do this TBADFLAG check when XTI spec
                 * is being extended with new and interesting flags
                 * everyday ?
                 */
                if ((flags & ~(TX_ALL_VALID_FLAGS)) != 0) {
                        t_errno = TBADFLAG;
                        sig_mutex_unlock(&tiptr->ti_lock);
                        return (-1);
                }
                if (flags & T_EXPEDITED)
                        tsdu_limit = tiptr->ti_etsdusize;
                else {
                        /* normal data */
                        tsdu_limit = tiptr->ti_tsdusize;
                }

                if ((tsdu_limit > 0) && /* limit meaningful and ... */
                    (nbytes > (uint32_t)tsdu_limit)) {
                        t_errno = TBADDATA;
                        sig_mutex_unlock(&tiptr->ti_lock);
                        return (-1);
                }

                /*
                 * Check for incoming disconnect or orderly release
                 * Did anyone say "performance" ? Didn't hear that.
                 */
                lookevent = _t_look_locked(fd, tiptr, 0, api_semantics);
                if (lookevent < 0) {
                        sv_errno = errno;
                        sig_mutex_unlock(&tiptr->ti_lock);
                        errno = sv_errno;
                        return (-1);
                }
                /*
                 * XNS 4 required the TLOOK error to be returned if there
                 * is any incoming T_ORDREL. XNS 5 does not require an
                 * error to be returned in such a case.
                 */
                if (lookevent == T_DISCONNECT ||
                    (api_semantics == TX_XTI_XNS4_API &&
                    lookevent == T_ORDREL)) {
                        t_errno = TLOOK;
                        sig_mutex_unlock(&tiptr->ti_lock);
                        return (-1);
                }
        }

        /* sending zero length data when not allowed */
        if (nbytes == 0 && !(tiptr->ti_prov_flag & (SENDZERO|OLD_SENDZERO))) {
                t_errno = TBADDATA;
                sig_mutex_unlock(&tiptr->ti_lock);
                return (-1);
        }

        doputmsg = (tiptr->ti_tsdusize != 0) || (flags & T_EXPEDITED);

        if (doputmsg) {
                /*
                 * Initialize ctlbuf for use in sending/receiving control part
                 * of the message.
                 */
                ctlbuf.maxlen = (int)sizeof (struct T_data_req);
                ctlbuf.len = (int)sizeof (struct T_data_req);
                ctlbuf.buf = (char *)&datareq;

                band = TI_NORMAL; /* band 0 */
                if (flags & T_EXPEDITED) {
                        datareq.PRIM_type = T_EXDATA_REQ;
                        if (! (tiptr->ti_prov_flag & EXPINLINE))
                                band = TI_EXPEDITED; /* band > 0 */
                } else
                        datareq.PRIM_type = T_DATA_REQ;
        }

        bytes_remaining = nbytes;
        curptr = buf;

        /*
         * Calls to send data (write or putmsg) can potentially
         * block, for MT case, we drop the lock and enable signals here
         * and acquire it back
         */
        sig_mutex_unlock(&tiptr->ti_lock);
        do {
                bytes_to_send = bytes_remaining;
                if (doputmsg) {
                        /*
                         * transport provider supports TSDU concept
                         * (unlike TCP) or it is expedited data.
                         * In this case do the fragmentation
                         */
                        if (bytes_to_send > (unsigned int)tiptr->ti_maxpsz) {
                                datareq.MORE_flag = 1;
                                bytes_to_send = (unsigned int)tiptr->ti_maxpsz;
                        } else {
                                if (flags&T_MORE)
                                        datareq.MORE_flag = 1;
                                else
                                        datareq.MORE_flag = 0;
                        }
                        databuf.maxlen = bytes_to_send;
                        databuf.len = bytes_to_send;
                        databuf.buf = curptr;
                        retval = putpmsg(fd, &ctlbuf, &databuf, band, MSG_BAND);
                        if (retval == 0)
                                bytes_sent = bytes_to_send;
                } else {
                        /*
                         * transport provider does *not* support TSDU concept
                         * (e.g. TCP) and it is not expedited data. A
                         * perf. optimization is used. Note: the T_MORE
                         * flag is ignored here even if set by the user.
                         */
                        retval = write(fd, curptr, bytes_to_send);
                        if (retval >= 0) {
                                /* Amount that was actually sent */
                                bytes_sent = retval;
                        }
                }

                if (retval < 0) {
                        if (nbytes == bytes_remaining) {
                                /*
                                 * Error on *first* putmsg/write attempt.
                                 * Return appropriate error
                                 */
                                if (errno == EAGAIN)
                                        t_errno = TFLOW;
                                else
                                        t_errno = TSYSERR;
                                return (-1); /* return error */
                        }
                        /*
                         * Not the first putmsg/write
                         * [ partial completion of t_snd() case.
                         *
                         * Error on putmsg/write attempt but
                         * some data was transmitted so don't
                         * return error. Don't attempt to
                         * send more (break from loop) but
                         * return OK.
                         */
                        break;
                }
                bytes_remaining = bytes_remaining - bytes_sent;
                curptr = curptr + bytes_sent;
        } while (bytes_remaining != 0);

        _T_TX_NEXTSTATE(T_SND, tiptr, "t_snd: invalid state event T_SND");
        return (nbytes - bytes_remaining);
}