/*      $NetBSD: clnt_vc.c,v 1.4 2000/07/14 08:40:42 fvdl Exp $ */

/*-
 * 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.
 */

#include <sys/cdefs.h>
/*
 * clnt_tcp.c, Implements a TCP/IP based, client side RPC.
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 *
 * TCP based RPC supports 'batched calls'.
 * A sequence of calls may be batched-up in a send buffer.  The rpc call
 * return immediately to the client even though the call was not necessarily
 * sent.  The batching occurs if the results' xdr routine is NULL (0) AND
 * the rpc timeout value is zero (see clnt.h, rpc).
 *
 * Clients should NOT casually batch calls that in fact return results; that is,
 * the server side should be aware that a call is batched and not produce any
 * return message.  Batched calls that produce many result messages can
 * deadlock (netlock) the client and the server....
 *
 * Now go hang yourself.
 */

/*
 * This code handles the special case of a NFSv4.n backchannel for
 * callback RPCs. It is similar to clnt_vc.c, but uses the TCP
 * connection provided by the client to the server.
 */

#include "opt_kern_tls.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ktls.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/pcpu.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sx.h>
#include <sys/syslog.h>
#include <sys/time.h>
#include <sys/uio.h>

#include <net/vnet.h>

#include <netinet/tcp.h>

#include <rpc/rpc.h>
#include <rpc/rpc_com.h>
#include <rpc/krpc.h>
#include <rpc/rpcsec_tls.h>

struct cmessage {
        struct cmsghdr cmsg;
        struct cmsgcred cmcred;
};

static void clnt_bck_geterr(CLIENT *, struct rpc_err *);
static bool_t clnt_bck_freeres(CLIENT *, xdrproc_t, void *);
static void clnt_bck_abort(CLIENT *);
static bool_t clnt_bck_control(CLIENT *, u_int, void *);
static void clnt_bck_close(CLIENT *);
static void clnt_bck_destroy(CLIENT *);

static const struct clnt_ops clnt_bck_ops = {
        .cl_abort =     clnt_bck_abort,
        .cl_geterr =    clnt_bck_geterr,
        .cl_freeres =   clnt_bck_freeres,
        .cl_close =     clnt_bck_close,
        .cl_destroy =   clnt_bck_destroy,
        .cl_control =   clnt_bck_control
};

/*
 * Create a client handle for a connection.
 * Default options are set, which the user can change using clnt_control()'s.
 * This code handles the special case of an NFSv4.1 session backchannel
 * call, which is sent on a TCP connection created against the server
 * by a client.
 */
void *
clnt_bck_create(
        struct socket *so,              /* Server transport socket. */
        const rpcprog_t prog,           /* program number */
        const rpcvers_t vers)           /* version number */
{
        CLIENT *cl;                     /* client handle */
        struct ct_data *ct = NULL;      /* client handle */
        struct timeval now;
        struct rpc_msg call_msg;
        static uint32_t disrupt;
        XDR xdrs;

        if (disrupt == 0)
                disrupt = (uint32_t)(long)so;

        cl = (CLIENT *)mem_alloc(sizeof (*cl));
        ct = (struct ct_data *)mem_alloc(sizeof (*ct));

        mtx_init(&ct->ct_lock, "ct->ct_lock", NULL, MTX_DEF);
        ct->ct_threads = 0;
        ct->ct_closing = FALSE;
        ct->ct_closed = FALSE;
        ct->ct_upcallrefs = 0;
        ct->ct_closeit = FALSE;

        /*
         * Set up private data struct
         */
        ct->ct_wait.tv_sec = -1;
        ct->ct_wait.tv_usec = -1;

        /*
         * Initialize call message
         */
        getmicrotime(&now);
        ct->ct_xid = ((uint32_t)++disrupt) ^ __RPC_GETXID(&now);
        call_msg.rm_xid = ct->ct_xid;
        call_msg.rm_direction = CALL;
        call_msg.rm_call.cb_rpcvers = RPC_MSG_VERSION;
        call_msg.rm_call.cb_prog = (uint32_t)prog;
        call_msg.rm_call.cb_vers = (uint32_t)vers;

        /*
         * pre-serialize the static part of the call msg and stash it away
         */
        xdrmem_create(&xdrs, ct->ct_mcallc, MCALL_MSG_SIZE,
            XDR_ENCODE);
        if (!xdr_callhdr(&xdrs, &call_msg))
                goto err;
        ct->ct_mpos = XDR_GETPOS(&xdrs);
        XDR_DESTROY(&xdrs);
        ct->ct_waitchan = "rpcbck";
        ct->ct_waitflag = 0;
        cl->cl_refs = 1;
        cl->cl_ops = &clnt_bck_ops;
        cl->cl_private = ct;
        cl->cl_auth = authnone_create();
        TAILQ_INIT(&ct->ct_pending);
        return (cl);

err:
        mtx_destroy(&ct->ct_lock);
        mem_free(ct, sizeof (struct ct_data));
        mem_free(cl, sizeof (CLIENT));
        return (NULL);
}

enum clnt_stat
clnt_bck_call(
        CLIENT          *cl,            /* client handle */
        struct rpc_callextra *ext,      /* call metadata */
        rpcproc_t       proc,           /* procedure number */
        struct mbuf     *args,          /* pointer to args */
        struct mbuf     **resultsp,     /* pointer to results */
        struct timeval  utimeout,
        SVCXPRT         *xprt)
{
        struct ct_data *ct = (struct ct_data *) cl->cl_private;
        AUTH *auth;
        struct rpc_err *errp;
        enum clnt_stat stat;
        XDR xdrs;
        struct rpc_msg reply_msg;
        bool_t ok;
        int nrefreshes = 2;             /* number of times to refresh cred */
        struct timeval timeout;
        uint32_t xid;
        struct mbuf *mreq = NULL, *results;
        struct ct_request *cr;
        int error, maxextsiz;
#ifdef KERN_TLS
        u_int maxlen;
#endif

        cr = malloc(sizeof(struct ct_request), M_RPC, M_WAITOK);

        mtx_lock(&ct->ct_lock);

        if (ct->ct_closing || ct->ct_closed) {
                mtx_unlock(&ct->ct_lock);
                free(cr, M_RPC);
                return (RPC_CANTSEND);
        }
        ct->ct_threads++;

        if (ext) {
                auth = ext->rc_auth;
                errp = &ext->rc_err;
        } else {
                auth = cl->cl_auth;
                errp = &ct->ct_error;
        }

        cr->cr_mrep = NULL;
        cr->cr_error = 0;

        if (ct->ct_wait.tv_usec == -1)
                timeout = utimeout;     /* use supplied timeout */
        else
                timeout = ct->ct_wait;  /* use default timeout */

call_again:
        mtx_assert(&ct->ct_lock, MA_OWNED);

        ct->ct_xid++;
        xid = ct->ct_xid;

        mtx_unlock(&ct->ct_lock);

        /*
         * Leave space to pre-pend the record mark.
         */
        mreq = m_gethdr(M_WAITOK, MT_DATA);
        mreq->m_data += sizeof(uint32_t);
        KASSERT(ct->ct_mpos + sizeof(uint32_t) <= MHLEN,
            ("RPC header too big"));
        bcopy(ct->ct_mcallc, mreq->m_data, ct->ct_mpos);
        mreq->m_len = ct->ct_mpos;

        /*
         * The XID is the first thing in the request.
         */
        *mtod(mreq, uint32_t *) = htonl(xid);

        xdrmbuf_create(&xdrs, mreq, XDR_ENCODE);

        errp->re_status = stat = RPC_SUCCESS;

        if ((!XDR_PUTINT32(&xdrs, &proc)) ||
            (!AUTH_MARSHALL(auth, xid, &xdrs,
             m_copym(args, 0, M_COPYALL, M_WAITOK)))) {
                errp->re_status = stat = RPC_CANTENCODEARGS;
                mtx_lock(&ct->ct_lock);
                goto out;
        }
        mreq->m_pkthdr.len = m_length(mreq, NULL);

        /*
         * Prepend a record marker containing the packet length.
         */
        M_PREPEND(mreq, sizeof(uint32_t), M_WAITOK);
        *mtod(mreq, uint32_t *) =
            htonl(0x80000000 | (mreq->m_pkthdr.len - sizeof(uint32_t)));

        cr->cr_xid = xid;
        mtx_lock(&ct->ct_lock);
        /*
         * Check to see if the client end has already started to close down
         * the connection. The svc code will have set ct_error.re_status
         * to RPC_CANTRECV if this is the case.
         * If the client starts to close down the connection after this
         * point, it will be detected later when cr_error is checked,
         * since the request is in the ct_pending queue.
         */
        if (ct->ct_error.re_status == RPC_CANTRECV) {
                if (errp != &ct->ct_error) {
                        errp->re_errno = ct->ct_error.re_errno;
                        errp->re_status = RPC_CANTRECV;
                }
                stat = RPC_CANTRECV;
                goto out;
        }
        TAILQ_INSERT_TAIL(&ct->ct_pending, cr, cr_link);
        mtx_unlock(&ct->ct_lock);

        /* For RPC-over-TLS, copy mrep to a chain of ext_pgs. */
        if ((xprt->xp_tls & RPCTLS_FLAGS_HANDSHAKE) != 0) {
                /*
                 * Copy the mbuf chain to a chain of
                 * ext_pgs mbuf(s) as required by KERN_TLS.
                 */
                maxextsiz = TLS_MAX_MSG_SIZE_V10_2;
#ifdef KERN_TLS
                if (rpctls_getinfo(&maxlen, false, false))
                        maxextsiz = min(maxextsiz, maxlen);
#endif
                mreq = _rpc_copym_into_ext_pgs(mreq, maxextsiz);
        }
        /*
         * sosend consumes mreq.
         */
        sx_xlock(&xprt->xp_lock);
        error = sosend(xprt->xp_socket, NULL, NULL, mreq, NULL, 0, curthread);
        mreq = NULL;
        if (error == EMSGSIZE) {
                SOCK_SENDBUF_LOCK(xprt->xp_socket);
                sbwait(xprt->xp_socket, SO_SND);
                SOCK_SENDBUF_UNLOCK(xprt->xp_socket);
                sx_xunlock(&xprt->xp_lock);
                AUTH_VALIDATE(auth, xid, NULL, NULL);
                mtx_lock(&ct->ct_lock);
                TAILQ_REMOVE(&ct->ct_pending, cr, cr_link);
                goto call_again;
        }
        sx_xunlock(&xprt->xp_lock);

        reply_msg.acpted_rply.ar_verf.oa_flavor = AUTH_NULL;
        reply_msg.acpted_rply.ar_verf.oa_base = cr->cr_verf;
        reply_msg.acpted_rply.ar_verf.oa_length = 0;
        reply_msg.acpted_rply.ar_results.where = NULL;
        reply_msg.acpted_rply.ar_results.proc = (xdrproc_t)xdr_void;

        mtx_lock(&ct->ct_lock);
        if (error) {
                TAILQ_REMOVE(&ct->ct_pending, cr, cr_link);
                errp->re_errno = error;
                errp->re_status = stat = RPC_CANTSEND;
                goto out;
        }

        /*
         * Check to see if we got an upcall while waiting for the
         * lock. In both these cases, the request has been removed
         * from ct->ct_pending.
         */
        if (cr->cr_error) {
                TAILQ_REMOVE(&ct->ct_pending, cr, cr_link);
                errp->re_errno = cr->cr_error;
                errp->re_status = stat = RPC_CANTRECV;
                goto out;
        }
        if (cr->cr_mrep) {
                TAILQ_REMOVE(&ct->ct_pending, cr, cr_link);
                goto got_reply;
        }

        /*
         * Hack to provide rpc-based message passing
         */
        if (timeout.tv_sec == 0 && timeout.tv_usec == 0) {
                TAILQ_REMOVE(&ct->ct_pending, cr, cr_link);
                errp->re_status = stat = RPC_TIMEDOUT;
                goto out;
        }

        error = msleep(cr, &ct->ct_lock, ct->ct_waitflag, ct->ct_waitchan,
            tvtohz(&timeout));

        TAILQ_REMOVE(&ct->ct_pending, cr, cr_link);

        if (error) {
                /*
                 * The sleep returned an error so our request is still
                 * on the list. Turn the error code into an
                 * appropriate client status.
                 */
                errp->re_errno = error;
                switch (error) {
                case EINTR:
                        stat = RPC_INTR;
                        break;
                case EWOULDBLOCK:
                        stat = RPC_TIMEDOUT;
                        break;
                default:
                        stat = RPC_CANTRECV;
                }
                errp->re_status = stat;
                goto out;
        } else {
                /*
                 * We were woken up by the svc thread.  If the
                 * upcall had a receive error, report that,
                 * otherwise we have a reply.
                 */
                if (cr->cr_error) {
                        errp->re_errno = cr->cr_error;
                        errp->re_status = stat = RPC_CANTRECV;
                        goto out;
                }
        }

got_reply:
        /*
         * Now decode and validate the response. We need to drop the
         * lock since xdr_replymsg may end up sleeping in malloc.
         */
        mtx_unlock(&ct->ct_lock);

        if (ext && ext->rc_feedback)
                ext->rc_feedback(FEEDBACK_OK, proc, ext->rc_feedback_arg);

        xdrmbuf_create(&xdrs, cr->cr_mrep, XDR_DECODE);
        ok = xdr_replymsg(&xdrs, &reply_msg);
        cr->cr_mrep = NULL;

        if (ok) {
                if ((reply_msg.rm_reply.rp_stat == MSG_ACCEPTED) &&
                    (reply_msg.acpted_rply.ar_stat == SUCCESS))
                        errp->re_status = stat = RPC_SUCCESS;
                else
                        stat = _seterr_reply(&reply_msg, errp);

                if (stat == RPC_SUCCESS) {
                        results = xdrmbuf_getall(&xdrs);
                        if (!AUTH_VALIDATE(auth, xid,
                            &reply_msg.acpted_rply.ar_verf, &results)) {
                                errp->re_status = stat = RPC_AUTHERROR;
                                errp->re_why = AUTH_INVALIDRESP;
                        } else {
                                KASSERT(results,
                                    ("auth validated but no result"));
                                *resultsp = results;
                        }
                }               /* end successful completion */
                /*
                 * If unsuccessful AND error is an authentication error
                 * then refresh credentials and try again, else break
                 */
                else if (stat == RPC_AUTHERROR)
                        /* maybe our credentials need to be refreshed ... */
                        if (nrefreshes > 0 && AUTH_REFRESH(auth, &reply_msg)) {
                                nrefreshes--;
                                XDR_DESTROY(&xdrs);
                                mtx_lock(&ct->ct_lock);
                                goto call_again;
                        }
                        /* end of unsuccessful completion */
                /* end of valid reply message */
        } else
                errp->re_status = stat = RPC_CANTDECODERES;
        XDR_DESTROY(&xdrs);
        mtx_lock(&ct->ct_lock);
out:
        mtx_assert(&ct->ct_lock, MA_OWNED);

        KASSERT(stat != RPC_SUCCESS || *resultsp,
            ("RPC_SUCCESS without reply"));

        if (mreq != NULL)
                m_freem(mreq);
        if (cr->cr_mrep != NULL)
                m_freem(cr->cr_mrep);

        ct->ct_threads--;
        if (ct->ct_closing)
                wakeup(ct);
                
        mtx_unlock(&ct->ct_lock);

        if (auth && stat != RPC_SUCCESS)
                AUTH_VALIDATE(auth, xid, NULL, NULL);

        free(cr, M_RPC);

        return (stat);
}

static void
clnt_bck_geterr(CLIENT *cl, struct rpc_err *errp)
{
        struct ct_data *ct = (struct ct_data *) cl->cl_private;

        *errp = ct->ct_error;
}

static bool_t
clnt_bck_freeres(CLIENT *cl, xdrproc_t xdr_res, void *res_ptr)
{
        XDR xdrs;
        bool_t dummy;

        xdrs.x_op = XDR_FREE;
        dummy = (*xdr_res)(&xdrs, res_ptr);

        return (dummy);
}

/*ARGSUSED*/
static void
clnt_bck_abort(CLIENT *cl)
{
}

static bool_t
clnt_bck_control(CLIENT *cl, u_int request, void *info)
{

        return (TRUE);
}

static void
clnt_bck_close(CLIENT *cl)
{
        struct ct_data *ct = (struct ct_data *) cl->cl_private;

        mtx_lock(&ct->ct_lock);

        if (ct->ct_closed) {
                mtx_unlock(&ct->ct_lock);
                return;
        }

        if (ct->ct_closing) {
                while (ct->ct_closing)
                        msleep(ct, &ct->ct_lock, 0, "rpcclose", 0);
                KASSERT(ct->ct_closed, ("client should be closed"));
                mtx_unlock(&ct->ct_lock);
                return;
        }

        ct->ct_closing = FALSE;
        ct->ct_closed = TRUE;
        mtx_unlock(&ct->ct_lock);
        wakeup(ct);
}

static void
clnt_bck_destroy(CLIENT *cl)
{
        struct ct_data *ct = (struct ct_data *) cl->cl_private;

        clnt_bck_close(cl);

        mtx_destroy(&ct->ct_lock);
        mem_free(ct, sizeof(struct ct_data));
        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));
}

/*
 * This call is done by the svc code when a backchannel RPC reply is
 * received.
 * For the server end, where callback RPCs to the client are performed,
 * xp_p2 points to the "CLIENT" and not the associated "struct ct_data"
 * so that svc_vc_destroy() can CLNT_RELEASE() the reference count on it.
 */
void
clnt_bck_svccall(void *arg, struct mbuf *mrep, uint32_t xid)
{
        CLIENT *cl = (CLIENT *)arg;
        struct ct_data *ct;
        struct ct_request *cr;
        int foundreq;

        ct = (struct ct_data *)cl->cl_private;
        mtx_lock(&ct->ct_lock);
        if (ct->ct_closing || ct->ct_closed) {
                mtx_unlock(&ct->ct_lock);
                m_freem(mrep);
                return;
        }

        ct->ct_upcallrefs++;
        /*
         * See if we can match this reply to a request.
         */
        foundreq = 0;
        TAILQ_FOREACH(cr, &ct->ct_pending, cr_link) {
                if (cr->cr_xid == xid) {
                        /*
                         * This one matches. We leave the reply mbuf list in
                         * cr->cr_mrep. Set the XID to zero so that we will
                         * ignore any duplicated replies.
                         */
                        cr->cr_xid = 0;
                        cr->cr_mrep = mrep;
                        cr->cr_error = 0;
                        foundreq = 1;
                        wakeup(cr);
                        break;
                }
        }

        ct->ct_upcallrefs--;
        if (ct->ct_upcallrefs < 0)
                panic("rpcvc svccall refcnt");
        if (ct->ct_upcallrefs == 0)
                wakeup(&ct->ct_upcallrefs);
        mtx_unlock(&ct->ct_lock);
        if (foundreq == 0)
                m_freem(mrep);
}