/*      $NetBSD: clnt_dg.c,v 1.4 2000/07/14 08:40:41 fvdl Exp $ */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2009, Sun Microsystems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * - Redistributions of source code must retain the above copyright notice, 
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice, 
 *   this list of conditions and the following disclaimer in the documentation 
 *   and/or other materials provided with the distribution.
 * - Neither the name of Sun Microsystems, Inc. nor the names of its 
 *   contributors may be used to endorse or promote products derived 
 *   from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 */
/*
 * Copyright (c) 1986-1991 by Sun Microsystems Inc. 
 */

/*
 * Implements a connectionless client side RPC.
 */

#include "namespace.h"
#include "reentrant.h"
#include <sys/types.h>
#include <sys/event.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/tree.h>
#include <arpa/inet.h>
#include <rpc/rpc.h>
#include <rpc/rpcsec_gss.h>
#include <assert.h>
#include <errno.h>
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <stdbool.h>
#include <unistd.h>
#include <err.h>
#include "un-namespace.h"
#include "rpc_com.h"
#include "mt_misc.h"


#ifdef _FREEFALL_CONFIG
/*
 * Disable RPC exponential back-off for FreeBSD.org systems.
 */
#define RPC_MAX_BACKOFF         1 /* second */
#else
#define RPC_MAX_BACKOFF         30 /* seconds */
#endif


static struct clnt_ops *clnt_dg_ops(void);
static bool_t time_not_ok(struct timeval *);
static enum clnt_stat clnt_dg_call(CLIENT *, rpcproc_t, xdrproc_t, void *,
            xdrproc_t, void *, struct timeval);
static void clnt_dg_geterr(CLIENT *, struct rpc_err *);
static bool_t clnt_dg_freeres(CLIENT *, xdrproc_t, void *);
static void clnt_dg_abort(CLIENT *);
static bool_t clnt_dg_control(CLIENT *, u_int, void *);
static void clnt_dg_destroy(CLIENT *);




/*
 *      This machinery implements per-fd locks for MT-safety.  It is not
 *      sufficient to do per-CLIENT handle locks for MT-safety because a
 *      user may create more than one CLIENT handle with the same fd behind
 *      it.  Therefore, we allocate an associative array of flags and condition
 *      variables (dg_fd).  The flags and the array are protected by the
 *      clnt_fd_lock mutex.  dg_fd[fd].lock == 1 => a call is active on some
 *      CLIENT handle created for that fd.  The current implementation holds
 *      locks across the entire RPC and reply, including retransmissions.  Yes,
 *      this is silly, and as soon as this code is proven to work, this should
 *      be the first thing fixed.  One step at a time.
 */
struct dg_fd {
        RB_ENTRY(dg_fd) dg_link;
        int fd;
        mutex_t mtx;
};
static inline int
cmp_dg_fd(struct dg_fd *a, struct dg_fd *b)
{
        if (a->fd > b->fd) {
                return (1);
        } else if (a->fd < b->fd) {
                return (-1);
        } else {
                return (0);
        }
}
RB_HEAD(dg_fd_list, dg_fd);
RB_PROTOTYPE(dg_fd_list, dg_fd, dg_link, cmp_dg_fd);
RB_GENERATE(dg_fd_list, dg_fd, dg_link, cmp_dg_fd);
struct dg_fd_list dg_fd_head = RB_INITIALIZER(&dg_fd_head);

/*
 * Find the lock structure for the given file descriptor, or initialize it if
 * it does not already exist.  The clnt_fd_lock mutex must be held.
 */
static struct dg_fd *
dg_fd_find(int fd)
{
        struct dg_fd key, *elem;

        key.fd = fd;
        elem = RB_FIND(dg_fd_list, &dg_fd_head, &key);
        if (elem == NULL) {
                elem = calloc(1, sizeof(*elem));
                elem->fd = fd;
                mutex_init(&elem->mtx, NULL);
                RB_INSERT(dg_fd_list, &dg_fd_head, elem);
        }
        return (elem);
}

static void
release_fd_lock(struct dg_fd *elem, sigset_t mask)
{
        mutex_unlock(&elem->mtx);
        thr_sigsetmask(SIG_SETMASK, &mask, NULL);
}

static const char mem_err_clnt_dg[] = "clnt_dg_create: out of memory";

/* VARIABLES PROTECTED BY clnt_fd_lock: dg_fd */

#define MCALL_MSG_SIZE 24

/*
 * Private data kept per client handle
 */
struct cu_data {
        int                     cu_fd;          /* connections fd */
        bool_t                  cu_closeit;     /* opened by library */
        struct sockaddr_storage cu_raddr;       /* remote address */
        int                     cu_rlen;
        struct timeval          cu_wait;        /* retransmit interval */
        struct timeval          cu_total;       /* total time for the call */
        struct rpc_err          cu_error;
        XDR                     cu_outxdrs;
        u_int                   cu_xdrpos;
        u_int                   cu_sendsz;      /* send size */
        char                    cu_outhdr[MCALL_MSG_SIZE];
        char                    *cu_outbuf;
        u_int                   cu_recvsz;      /* recv size */
        int                     cu_async;
        int                     cu_connect;     /* Use connect(). */
        int                     cu_connected;   /* Have done connect(). */
        struct kevent           cu_kin;
        int                     cu_kq;
        char                    cu_inbuf[1];
};

/*
 * Connection less client creation returns with client handle parameters.
 * Default options are set, which the user can change using clnt_control().
 * fd should be open and bound.
 * NB: The rpch->cl_auth is initialized to null authentication.
 *      Caller may wish to set this something more useful.
 *
 * sendsz and recvsz are the maximum allowable packet sizes that can be
 * sent and received. Normally they are the same, but they can be
 * changed to improve the program efficiency and buffer allocation.
 * If they are 0, use the transport default.
 *
 * If svcaddr is NULL, returns NULL.
 *
 * fd      - open file descriptor
 * svcaddr - servers address
 * program - program number
 * version - version number
 * sendsz  - buffer recv size
 * recvsz  - buffer send size
 */
CLIENT *
clnt_dg_create(int fd, const struct netbuf *svcaddr, rpcprog_t program,
    rpcvers_t version, u_int sendsz, u_int recvsz)
{
        CLIENT *cl = NULL;              /* client handle */
        struct cu_data *cu = NULL;      /* private data */
        struct timeval now;
        struct rpc_msg call_msg;
        struct __rpc_sockinfo si;
        int one = 1;

        if (svcaddr == NULL) {
                rpc_createerr.cf_stat = RPC_UNKNOWNADDR;
                return (NULL);
        }

        if (!__rpc_fd2sockinfo(fd, &si)) {
                rpc_createerr.cf_stat = RPC_TLIERROR;
                rpc_createerr.cf_error.re_errno = 0;
                return (NULL);
        }
        /*
         * Find the receive and the send size
         */
        sendsz = __rpc_get_t_size(si.si_af, si.si_proto, (int)sendsz);
        recvsz = __rpc_get_t_size(si.si_af, si.si_proto, (int)recvsz);
        if ((sendsz == 0) || (recvsz == 0)) {
                rpc_createerr.cf_stat = RPC_TLIERROR; /* XXX */
                rpc_createerr.cf_error.re_errno = 0;
                return (NULL);
        }

        if ((cl = mem_alloc(sizeof (CLIENT))) == NULL)
                goto err1;
        /*
         * Should be multiple of 4 for XDR.
         */
        sendsz = ((sendsz + 3) / 4) * 4;
        recvsz = ((recvsz + 3) / 4) * 4;
        cu = mem_alloc(sizeof (*cu) + sendsz + recvsz);
        if (cu == NULL)
                goto err1;
        (void) memcpy(&cu->cu_raddr, svcaddr->buf, (size_t)svcaddr->len);
        cu->cu_rlen = svcaddr->len;
        cu->cu_outbuf = &cu->cu_inbuf[recvsz];
        /* Other values can also be set through clnt_control() */
        cu->cu_wait.tv_sec = 15;        /* heuristically chosen */
        cu->cu_wait.tv_usec = 0;
        cu->cu_total.tv_sec = -1;
        cu->cu_total.tv_usec = -1;
        cu->cu_sendsz = sendsz;
        cu->cu_recvsz = recvsz;
        cu->cu_async = FALSE;
        cu->cu_connect = FALSE;
        cu->cu_connected = FALSE;
        (void) gettimeofday(&now, NULL);
        call_msg.rm_xid = __RPC_GETXID(&now);
        call_msg.rm_call.cb_prog = program;
        call_msg.rm_call.cb_vers = version;
        xdrmem_create(&(cu->cu_outxdrs), cu->cu_outhdr, MCALL_MSG_SIZE,
            XDR_ENCODE);
        if (! xdr_callhdr(&cu->cu_outxdrs, &call_msg)) {
                rpc_createerr.cf_stat = RPC_CANTENCODEARGS;  /* XXX */
                rpc_createerr.cf_error.re_errno = 0;
                goto err2;
        }
        cu->cu_xdrpos = XDR_GETPOS(&(cu->cu_outxdrs));
        XDR_DESTROY(&cu->cu_outxdrs);
        xdrmem_create(&cu->cu_outxdrs, cu->cu_outbuf, sendsz, XDR_ENCODE);

        /* XXX fvdl - do we still want this? */
#if 0
        (void)bindresvport_sa(fd, (struct sockaddr *)svcaddr->buf);
#endif
        _ioctl(fd, FIONBIO, (char *)(void *)&one);

        /*
         * By default, closeit is always FALSE. It is users responsibility
         * to do a close on it, else the user may use clnt_control
         * to let clnt_destroy do it for him/her.
         */
        cu->cu_closeit = FALSE;
        cu->cu_fd = fd;
        cl->cl_ops = clnt_dg_ops();
        cl->cl_private = (caddr_t)(void *)cu;
        cl->cl_auth = authnone_create();
        cl->cl_tp = NULL;
        cl->cl_netid = NULL;
        cu->cu_kq = -1;
        EV_SET(&cu->cu_kin, cu->cu_fd, EVFILT_READ, EV_ADD, 0, 0, 0);
        return (cl);
err1:
        warnx(mem_err_clnt_dg);
        rpc_createerr.cf_stat = RPC_SYSTEMERROR;
        rpc_createerr.cf_error.re_errno = errno;
err2:
        if (cl) {
                mem_free(cl, sizeof (CLIENT));
                if (cu)
                        mem_free(cu, sizeof (*cu) + sendsz + recvsz);
        }
        return (NULL);
}

/*
 * cl       - client handle
 * proc     - procedure number
 * xargs    - xdr routine for args
 * argsp    - pointer to args
 * xresults - xdr routine for results
 * resultsp - pointer to results
 * utimeout - seconds to wait before giving up
 */
static enum clnt_stat
clnt_dg_call(CLIENT *cl, rpcproc_t proc, xdrproc_t xargs, void *argsp,
    xdrproc_t xresults, void *resultsp, struct timeval utimeout)
{
        struct cu_data *cu = (struct cu_data *)cl->cl_private;
        XDR *xdrs;
        size_t outlen = 0;
        struct rpc_msg reply_msg;
        XDR reply_xdrs;
        bool_t ok;
        int nrefreshes = 2;             /* number of times to refresh cred */
        int nretries = 0;               /* number of times we retransmitted */
        struct timeval timeout;
        struct timeval retransmit_time;
        struct timeval next_sendtime, starttime, time_waited, tv;
        struct timespec ts;
        struct kevent kv;
        struct sockaddr *sa;
        struct dg_fd *elem;
        sigset_t mask;
        sigset_t newmask;
        socklen_t salen;
        ssize_t recvlen = 0;
        int kin_len, n;
        u_int32_t xid;

        outlen = 0;
        sigfillset(&newmask);
        thr_sigsetmask(SIG_SETMASK, &newmask, &mask);
        mutex_lock(&clnt_fd_lock);
        elem = dg_fd_find(cu->cu_fd);
        mutex_unlock(&clnt_fd_lock);
        mutex_lock(&elem->mtx);
        if (cu->cu_total.tv_usec == -1) {
                timeout = utimeout;     /* use supplied timeout */
        } else {
                timeout = cu->cu_total; /* use default timeout */
        }

        if (cu->cu_connect && !cu->cu_connected) {
                if (_connect(cu->cu_fd, (struct sockaddr *)&cu->cu_raddr,
                    cu->cu_rlen) < 0) {
                        cu->cu_error.re_errno = errno;
                        cu->cu_error.re_status = RPC_CANTSEND;
                        goto out;
                }
                cu->cu_connected = 1;
        }
        if (cu->cu_connected) {
                sa = NULL;
                salen = 0;
        } else {
                sa = (struct sockaddr *)&cu->cu_raddr;
                salen = cu->cu_rlen;
        }
        time_waited.tv_sec = 0;
        time_waited.tv_usec = 0;
        retransmit_time = next_sendtime = cu->cu_wait;
        gettimeofday(&starttime, NULL);

        /* Clean up in case the last call ended in a longjmp(3) call. */
        if (cu->cu_kq >= 0)
                _close(cu->cu_kq);
        if ((cu->cu_kq = kqueue()) < 0) {
                cu->cu_error.re_errno = errno;
                cu->cu_error.re_status = RPC_CANTSEND;
                goto out;
        }
        kin_len = 1;

call_again:
        if (cu->cu_async == TRUE && xargs == NULL)
                goto get_reply;
        /*
         * the transaction is the first thing in the out buffer
         * XXX Yes, and it's in network byte order, so we should to
         * be careful when we increment it, shouldn't we.
         */
        xid = ntohl(*(u_int32_t *)(void *)(cu->cu_outhdr));
        xid++;
        *(u_int32_t *)(void *)(cu->cu_outhdr) = htonl(xid);
call_again_same_xid:
        xdrs = &(cu->cu_outxdrs);
        xdrs->x_op = XDR_ENCODE;
        XDR_SETPOS(xdrs, 0);

        if (cl->cl_auth->ah_cred.oa_flavor != RPCSEC_GSS) {
                if ((! XDR_PUTBYTES(xdrs, cu->cu_outhdr, cu->cu_xdrpos)) ||
                    (! XDR_PUTINT32(xdrs, &proc)) ||
                    (! AUTH_MARSHALL(cl->cl_auth, xdrs)) ||
                    (! (*xargs)(xdrs, argsp))) {
                        cu->cu_error.re_status = RPC_CANTENCODEARGS;
                        goto out;
                }
        } else {
                *(uint32_t *) &cu->cu_outhdr[cu->cu_xdrpos] = htonl(proc);
                if (!__rpc_gss_wrap(cl->cl_auth, cu->cu_outhdr,
                        cu->cu_xdrpos + sizeof(uint32_t),
                        xdrs, xargs, argsp)) {
                        cu->cu_error.re_status = RPC_CANTENCODEARGS;
                        goto out;
                }
        }
        outlen = (size_t)XDR_GETPOS(xdrs);

send_again:
        if (_sendto(cu->cu_fd, cu->cu_outbuf, outlen, 0, sa, salen) != outlen) {
                cu->cu_error.re_errno = errno;
                cu->cu_error.re_status = RPC_CANTSEND;
                goto out;
        }

        /*
         * Hack to provide rpc-based message passing
         */
        if (timeout.tv_sec == 0 && timeout.tv_usec == 0) {
                cu->cu_error.re_status = RPC_TIMEDOUT;
                goto out;
        }

get_reply:

        /*
         * sub-optimal code appears here because we have
         * some clock time to spare while the packets are in flight.
         * (We assume that this is actually only executed once.)
         */
        reply_msg.acpted_rply.ar_verf = _null_auth;
        if (cl->cl_auth->ah_cred.oa_flavor != RPCSEC_GSS) {
                reply_msg.acpted_rply.ar_results.where = resultsp;
                reply_msg.acpted_rply.ar_results.proc = xresults;
        } else {
                reply_msg.acpted_rply.ar_results.where = NULL;
                reply_msg.acpted_rply.ar_results.proc = (xdrproc_t)xdr_void;
        }

        for (;;) {
                /* Decide how long to wait. */
                if (timercmp(&next_sendtime, &timeout, <))
                        timersub(&next_sendtime, &time_waited, &tv);
                else
                        timersub(&timeout, &time_waited, &tv);
                if (tv.tv_sec < 0 || tv.tv_usec < 0)
                        tv.tv_sec = tv.tv_usec = 0;
                TIMEVAL_TO_TIMESPEC(&tv, &ts);

                n = _kevent(cu->cu_kq, &cu->cu_kin, kin_len, &kv, 1, &ts);
                /* We don't need to register the event again. */
                kin_len = 0;

                if (n == 1) {
                        if (kv.flags & EV_ERROR) {
                                cu->cu_error.re_errno = kv.data;
                                cu->cu_error.re_status = RPC_CANTRECV;
                                goto out;
                        }
                        /* We have some data now */
                        do {
                                recvlen = _recvfrom(cu->cu_fd, cu->cu_inbuf,
                                    cu->cu_recvsz, 0, NULL, NULL);
                        } while (recvlen < 0 && errno == EINTR);
                        if (recvlen < 0 && errno != EWOULDBLOCK) {
                                cu->cu_error.re_errno = errno;
                                cu->cu_error.re_status = RPC_CANTRECV;
                                goto out;
                        }
                        if (recvlen >= sizeof(u_int32_t) &&
                            (cu->cu_async == TRUE ||
                            *((u_int32_t *)(void *)(cu->cu_inbuf)) ==
                            *((u_int32_t *)(void *)(cu->cu_outbuf)))) {
                                /* We now assume we have the proper reply. */
                                break;
                        }
                }
                if (n == -1 && errno != EINTR) {
                        cu->cu_error.re_errno = errno;
                        cu->cu_error.re_status = RPC_CANTRECV;
                        goto out;
                }
                gettimeofday(&tv, NULL);
                timersub(&tv, &starttime, &time_waited);

                /* Check for timeout. */
                if (timercmp(&time_waited, &timeout, >)) {
                        cu->cu_error.re_status = RPC_TIMEDOUT;
                        goto out;
                }

                /* Retransmit if necessary. */          
                if (timercmp(&time_waited, &next_sendtime, >)) {
                        /* update retransmit_time */
                        if (retransmit_time.tv_sec < RPC_MAX_BACKOFF)
                                timeradd(&retransmit_time, &retransmit_time,
                                    &retransmit_time);
                        timeradd(&next_sendtime, &retransmit_time,
                            &next_sendtime);
                        nretries++;

                        /*
                         * When retransmitting a RPCSEC_GSS message,
                         * we must use a new sequence number (handled
                         * by __rpc_gss_wrap above).
                         */
                        if (cl->cl_auth->ah_cred.oa_flavor != RPCSEC_GSS)
                                goto send_again;
                        else
                                goto call_again_same_xid;
                }
        }

        /*
         * now decode and validate the response
         */

        xdrmem_create(&reply_xdrs, cu->cu_inbuf, (u_int)recvlen, XDR_DECODE);
        ok = xdr_replymsg(&reply_xdrs, &reply_msg);
        /* XDR_DESTROY(&reply_xdrs);    save a few cycles on noop destroy */
        if (ok) {
                if ((reply_msg.rm_reply.rp_stat == MSG_ACCEPTED) &&
                        (reply_msg.acpted_rply.ar_stat == SUCCESS))
                        cu->cu_error.re_status = RPC_SUCCESS;
                else
                        _seterr_reply(&reply_msg, &(cu->cu_error));

                if (cu->cu_error.re_status == RPC_SUCCESS) {
                        if (! AUTH_VALIDATE(cl->cl_auth,
                                            &reply_msg.acpted_rply.ar_verf)) {
                                if (nretries &&
                                    cl->cl_auth->ah_cred.oa_flavor
                                    == RPCSEC_GSS)
                                        /*
                                         * If we retransmitted, its
                                         * possible that we will
                                         * receive a reply for one of
                                         * the earlier transmissions
                                         * (which will use an older
                                         * RPCSEC_GSS sequence
                                         * number). In this case, just
                                         * go back and listen for a
                                         * new reply. We could keep a
                                         * record of all the seq
                                         * numbers we have transmitted
                                         * so far so that we could
                                         * accept a reply for any of
                                         * them here.
                                         */
                                        goto get_reply;
                                cu->cu_error.re_status = RPC_AUTHERROR;
                                cu->cu_error.re_why = AUTH_INVALIDRESP;
                        } else {
                                if (cl->cl_auth->ah_cred.oa_flavor
                                    == RPCSEC_GSS) {
                                        if (!__rpc_gss_unwrap(cl->cl_auth,
                                                &reply_xdrs, xresults,
                                                resultsp))
                                                cu->cu_error.re_status =
                                                        RPC_CANTDECODERES;
                                }
                        }
                        if (reply_msg.acpted_rply.ar_verf.oa_base != NULL) {
                                xdrs->x_op = XDR_FREE;
                                (void) xdr_opaque_auth(xdrs,
                                        &(reply_msg.acpted_rply.ar_verf));
                        }
                }               /* end successful completion */
                /*
                 * If unsuccessful AND error is an authentication error
                 * then refresh credentials and try again, else break
                 */
                else if (cu->cu_error.re_status == RPC_AUTHERROR)
                        /* maybe our credentials need to be refreshed ... */
                        if (nrefreshes > 0 &&
                            AUTH_REFRESH(cl->cl_auth, &reply_msg)) {
                                nrefreshes--;
                                goto call_again;
                        }
                /* end of unsuccessful completion */
        }       /* end of valid reply message */
        else {
                cu->cu_error.re_status = RPC_CANTDECODERES;

        }
out:
        if (cu->cu_kq >= 0)
                _close(cu->cu_kq);
        cu->cu_kq = -1;
        release_fd_lock(elem, mask);
        return (cu->cu_error.re_status);
}

static void
clnt_dg_geterr(CLIENT *cl, struct rpc_err *errp)
{
        struct cu_data *cu = (struct cu_data *)cl->cl_private;

        *errp = cu->cu_error;
}

static bool_t
clnt_dg_freeres(CLIENT *cl, xdrproc_t xdr_res, void *res_ptr)
{
        struct cu_data *cu = (struct cu_data *)cl->cl_private;
        struct dg_fd *elem;
        XDR *xdrs = &(cu->cu_outxdrs);
        bool_t dummy;
        sigset_t mask;
        sigset_t newmask;

        sigfillset(&newmask);
        thr_sigsetmask(SIG_SETMASK, &newmask, &mask);
        mutex_lock(&clnt_fd_lock);
        elem = dg_fd_find(cu->cu_fd);
        mutex_lock(&elem->mtx);
        xdrs->x_op = XDR_FREE;
        dummy = (*xdr_res)(xdrs, res_ptr);
        mutex_unlock(&clnt_fd_lock);
        release_fd_lock(elem, mask);
        return (dummy);
}

/*ARGSUSED*/
static void
clnt_dg_abort(CLIENT *h)
{
}

static bool_t
clnt_dg_control(CLIENT *cl, u_int request, void *info)
{
        struct cu_data *cu = (struct cu_data *)cl->cl_private;
        struct netbuf *addr;
        struct dg_fd *elem;
        sigset_t mask;
        sigset_t newmask;

        sigfillset(&newmask);
        thr_sigsetmask(SIG_SETMASK, &newmask, &mask);
        mutex_lock(&clnt_fd_lock);
        elem = dg_fd_find(cu->cu_fd);
        mutex_unlock(&clnt_fd_lock);
        mutex_lock(&elem->mtx);
        switch (request) {
        case CLSET_FD_CLOSE:
                cu->cu_closeit = TRUE;
                release_fd_lock(elem, mask);
                return (TRUE);
        case CLSET_FD_NCLOSE:
                cu->cu_closeit = FALSE;
                release_fd_lock(elem, mask);
                return (TRUE);
        }

        /* for other requests which use info */
        if (info == NULL) {
                release_fd_lock(elem, mask);
                return (FALSE);
        }
        switch (request) {
        case CLSET_TIMEOUT:
                if (time_not_ok((struct timeval *)info)) {
                        release_fd_lock(elem, mask);
                        return (FALSE);
                }
                cu->cu_total = *(struct timeval *)info;
                break;
        case CLGET_TIMEOUT:
                *(struct timeval *)info = cu->cu_total;
                break;
        case CLGET_SERVER_ADDR:         /* Give him the fd address */
                /* Now obsolete. Only for backward compatibility */
                (void) memcpy(info, &cu->cu_raddr, (size_t)cu->cu_rlen);
                break;
        case CLSET_RETRY_TIMEOUT:
                if (time_not_ok((struct timeval *)info)) {
                        release_fd_lock(elem, mask);
                        return (FALSE);
                }
                cu->cu_wait = *(struct timeval *)info;
                break;
        case CLGET_RETRY_TIMEOUT:
                *(struct timeval *)info = cu->cu_wait;
                break;
        case CLGET_FD:
                *(int *)info = cu->cu_fd;
                break;
        case CLGET_SVC_ADDR:
                addr = (struct netbuf *)info;
                addr->buf = &cu->cu_raddr;
                addr->len = cu->cu_rlen;
                addr->maxlen = sizeof cu->cu_raddr;
                break;
        case CLSET_SVC_ADDR:            /* set to new address */
                addr = (struct netbuf *)info;
                if (addr->len < sizeof cu->cu_raddr) {
                        release_fd_lock(elem, mask);
                        return (FALSE);
                }
                (void) memcpy(&cu->cu_raddr, addr->buf, addr->len);
                cu->cu_rlen = addr->len;
                break;
        case CLGET_XID:
                /*
                 * use the knowledge that xid is the
                 * first element in the call structure *.
                 * This will get the xid of the PREVIOUS call
                 */
                *(u_int32_t *)info =
                    ntohl(*(u_int32_t *)(void *)cu->cu_outhdr);
                break;

        case CLSET_XID:
                /* This will set the xid of the NEXT call */
                *(u_int32_t *)(void *)cu->cu_outhdr =
                    htonl(*(u_int32_t *)info - 1);
                /* decrement by 1 as clnt_dg_call() increments once */
                break;

        case CLGET_VERS:
                /*
                 * This RELIES on the information that, in the call body,
                 * the version number field is the fifth field from the
                 * beginning of the RPC header. MUST be changed if the
                 * call_struct is changed
                 */
                *(u_int32_t *)info =
                    ntohl(*(u_int32_t *)(void *)(cu->cu_outhdr +
                    4 * BYTES_PER_XDR_UNIT));
                break;

        case CLSET_VERS:
                *(u_int32_t *)(void *)(cu->cu_outhdr + 4 * BYTES_PER_XDR_UNIT)
                        = htonl(*(u_int32_t *)info);
                break;

        case CLGET_PROG:
                /*
                 * This RELIES on the information that, in the call body,
                 * the program number field is the fourth field from the
                 * beginning of the RPC header. MUST be changed if the
                 * call_struct is changed
                 */
                *(u_int32_t *)info =
                    ntohl(*(u_int32_t *)(void *)(cu->cu_outhdr +
                    3 * BYTES_PER_XDR_UNIT));
                break;

        case CLSET_PROG:
                *(u_int32_t *)(void *)(cu->cu_outhdr + 3 * BYTES_PER_XDR_UNIT)
                        = htonl(*(u_int32_t *)info);
                break;
        case CLSET_ASYNC:
                cu->cu_async = *(int *)info;
                break;
        case CLSET_CONNECT:
                cu->cu_connect = *(int *)info;
                break;
        default:
                release_fd_lock(elem, mask);
                return (FALSE);
        }
        release_fd_lock(elem, mask);
        return (TRUE);
}

static void
clnt_dg_destroy(CLIENT *cl)
{
        struct cu_data *cu = (struct cu_data *)cl->cl_private;
        struct dg_fd *elem;
        int cu_fd = cu->cu_fd;
        sigset_t mask;
        sigset_t newmask;

        sigfillset(&newmask);
        thr_sigsetmask(SIG_SETMASK, &newmask, &mask);
        mutex_lock(&clnt_fd_lock);
        elem = dg_fd_find(cu_fd);
        mutex_lock(&elem->mtx);
        if (cu->cu_closeit)
                (void)_close(cu_fd);
        if (cu->cu_kq >= 0)
                _close(cu->cu_kq);
        XDR_DESTROY(&(cu->cu_outxdrs));
        mem_free(cu, (sizeof (*cu) + cu->cu_sendsz + cu->cu_recvsz));
        if (cl->cl_netid && cl->cl_netid[0])
                mem_free(cl->cl_netid, strlen(cl->cl_netid) +1);
        if (cl->cl_tp && cl->cl_tp[0])
                mem_free(cl->cl_tp, strlen(cl->cl_tp) +1);
        mem_free(cl, sizeof (CLIENT));
        mutex_unlock(&clnt_fd_lock);
        release_fd_lock(elem, mask);
}

static struct clnt_ops *
clnt_dg_ops(void)
{
        static struct clnt_ops ops;
        sigset_t mask;
        sigset_t newmask;

/* VARIABLES PROTECTED BY ops_lock: ops */

        sigfillset(&newmask);
        thr_sigsetmask(SIG_SETMASK, &newmask, &mask);
        mutex_lock(&ops_lock);
        if (ops.cl_call == NULL) {
                ops.cl_call = clnt_dg_call;
                ops.cl_abort = clnt_dg_abort;
                ops.cl_geterr = clnt_dg_geterr;
                ops.cl_freeres = clnt_dg_freeres;
                ops.cl_destroy = clnt_dg_destroy;
                ops.cl_control = clnt_dg_control;
        }
        mutex_unlock(&ops_lock);
        thr_sigsetmask(SIG_SETMASK, &mask, NULL);
        return (&ops);
}

/*
 * Make sure that the time is not garbage.  -1 value is allowed.
 */
static bool_t
time_not_ok(struct timeval *t)
{
        return (t->tv_sec < -1 || t->tv_sec > 100000000 ||
                t->tv_usec < -1 || t->tv_usec > 1000000);
}