/*      $OpenBSD: clnt_udp.c,v 1.42 2024/04/02 08:51:06 jsg Exp $ */

/*
 * Copyright (c) 2010, Oracle America, Inc.
 *
 * 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 the "Oracle America, 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.
 */

/*
 * clnt_udp.c, Implements a UDP/IP based, client side RPC.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <rpc/rpc.h>
#include <sys/socket.h>
#include <netdb.h>
#include <errno.h>
#include "clnt_udp.h"

/*
 * UDP bases client side rpc operations
 */
static enum clnt_stat   clntudp_call(CLIENT *, u_long, xdrproc_t, caddr_t,
                            xdrproc_t, caddr_t, struct timeval);
static void             clntudp_abort(CLIENT *);
static void             clntudp_geterr(CLIENT *, struct rpc_err *);
static bool_t           clntudp_freeres(CLIENT *, xdrproc_t, caddr_t);
static bool_t           clntudp_control(CLIENT *, u_int, void *);
static void             clntudp_destroy(CLIENT *);

static const struct clnt_ops udp_ops = {
        clntudp_call,
        clntudp_abort,
        clntudp_geterr,
        clntudp_freeres,
        clntudp_destroy,
        clntudp_control
};

int
clntudp_bufcreate1(struct clntudp_bufcreate_args *args)
{
        args->cl = (CLIENT *)mem_alloc(sizeof(CLIENT));
        if (args->cl == NULL) {
                rpc_createerr.cf_stat = RPC_SYSTEMERROR;
                rpc_createerr.cf_error.re_errno = errno;
                return -1;
        }
        args->sendsz = ((args->sendsz + 3) / 4) * 4;
        args->recvsz = ((args->recvsz + 3) / 4) * 4;
        args->cu = (struct cu_data *)mem_alloc(sizeof(*args->cu) +
            args->sendsz + args->recvsz);
        if (args->cu == NULL) {
                rpc_createerr.cf_stat = RPC_SYSTEMERROR;
                rpc_createerr.cf_error.re_errno = errno;
                return -1;
        }
        args->cu->cu_outbuf = &args->cu->cu_inbuf[args->recvsz];
        args->cl->cl_ops = &udp_ops;
        args->cl->cl_private = (caddr_t)args->cu;
        args->cu->cu_connected = 0;
        args->cu->cu_rlen = sizeof (args->cu->cu_raddr);
        args->cu->cu_wait = args->wait;
        args->cu->cu_total.tv_sec = -1;
        args->cu->cu_total.tv_usec = -1;
        args->cu->cu_sendsz = args->sendsz;
        args->cu->cu_recvsz = args->recvsz;
        args->cu->cu_closeit = FALSE;
        args->call_msg.rm_xid = arc4random();
        args->call_msg.rm_direction = CALL;
        args->call_msg.rm_call.cb_rpcvers = RPC_MSG_VERSION;
        args->call_msg.rm_call.cb_prog = args->program;
        args->call_msg.rm_call.cb_vers = args->version;
        return 0;
}

int
clntudp_bufcreate2(struct clntudp_bufcreate_args *args)
{
        xdrmem_create(&(args->cu->cu_outxdrs), args->cu->cu_outbuf,
            args->sendsz, XDR_ENCODE);
        if (!xdr_callhdr(&(args->cu->cu_outxdrs), &args->call_msg))
                return -1;
        args->cu->cu_xdrpos = XDR_GETPOS(&(args->cu->cu_outxdrs));
        args->cl->cl_auth = authnone_create();
        if (args->cl->cl_auth == NULL) {
                rpc_createerr.cf_stat = RPC_SYSTEMERROR;
                rpc_createerr.cf_error.re_errno = errno;
                return -1;
        }
        return 0;
}

/*
 * Create a UDP based client handle.
 * If *sockp<0, *sockp is set to a newly created UPD socket.  (***)
 * If raddr->sin_port is 0 a binder on the remote machine
 * is consulted for the correct port number.                  (***)
 * NB: It is the client's responsibility to close *sockp, unless
 *      clntudp_bufcreate() was called with *sockp = -1 (so it created
 *      the socket), and CLNT_DESTROY() is used.
 * NB: The rpch->cl_auth is initialized to null authentication.
 *     Caller may wish to set this something more useful.
 *
 * wait is the amount of time used between retransmitting a call if
 * no response has been heard;  retransmission occurs until the actual
 * rpc call times out.
 *
 * sendsz and recvsz are the maximum allowable packet sizes that can be
 * sent and received.
 *
 * This is a reduced-functionality version of clntudp_bufcreate() that
 * does not allocate socket or binding (***, above).
 * The official function clntudp_bufcreate(), which does perform those
 * two steps, is in clnt_udp_bufcreate.c.  This split avoids pulling
 * socket / portmap related code into programs only using getpwent / YP code.
 */

CLIENT *
clntudp_bufcreate_simple(struct sockaddr_in *raddr, u_long program, u_long version,
    struct timeval wait, int *sockp, u_int sendsz, u_int recvsz)
{
        struct clntudp_bufcreate_args args;

        args.raddr = raddr;
        args.program = program;
        args.version = version;
        args.wait = wait;
        args.sockp = sockp;
        args.sendsz = sendsz;
        args.recvsz = recvsz;
        args.cl = NULL;
        args.cu = NULL;

        if (clntudp_bufcreate1(&args) == -1)
                goto fooy;
        args.cu->cu_raddr = *raddr;
        args.cu->cu_sock = *sockp;
        if (clntudp_bufcreate2(&args) == -1)
                goto fooy;
        return (args.cl);
fooy:
        if (args.cu)
                mem_free((caddr_t)args.cu,
                    sizeof(*args.cu) + args.sendsz + args.recvsz);
        if (args.cl)
                mem_free((caddr_t)args.cl, sizeof(CLIENT));
        return (NULL);
}

static enum clnt_stat 
clntudp_call(CLIENT *cl,        /* client handle */
    u_long proc,                /* procedure number */
    xdrproc_t xargs,            /* xdr routine for args */
    caddr_t argsp,              /* pointer to args */
    xdrproc_t xresults,         /* xdr routine for results */
    caddr_t resultsp,           /* pointer to results */
    struct timeval utimeout)    /* seconds to wait before giving up */
{
        struct cu_data *cu = (struct cu_data *)cl->cl_private;
        XDR *xdrs;
        int outlen;
        int inlen;
        int ret;
        socklen_t fromlen;
        struct pollfd pfd[1];
        struct sockaddr_in from;
        struct rpc_msg reply_msg;
        XDR reply_xdrs;
        struct timespec time_waited, start, after, duration, wait;
        bool_t ok;
        int nrefreshes = 2;     /* number of times to refresh cred */
        struct timespec timeout;

        if (cu->cu_total.tv_usec == -1)
                TIMEVAL_TO_TIMESPEC(&utimeout, &timeout);     /* use supplied timeout */
        else
                TIMEVAL_TO_TIMESPEC(&cu->cu_total, &timeout); /* use default timeout */

        pfd[0].fd = cu->cu_sock;
        pfd[0].events = POLLIN;
        timespecclear(&time_waited);
        TIMEVAL_TO_TIMESPEC(&cu->cu_wait, &wait);
call_again:
        xdrs = &(cu->cu_outxdrs);
        xdrs->x_op = XDR_ENCODE;
        XDR_SETPOS(xdrs, cu->cu_xdrpos);
        /*
         * the transaction is the first thing in the out buffer
         */
        (*(u_short *)(cu->cu_outbuf))++;
        if (!XDR_PUTLONG(xdrs, (long *)&proc) ||
            !AUTH_MARSHALL(cl->cl_auth, xdrs) ||
            !(*xargs)(xdrs, argsp)) {
                return (cu->cu_error.re_status = RPC_CANTENCODEARGS);
        }
        outlen = (int)XDR_GETPOS(xdrs);

send_again:
        if (cu->cu_connected)
                ret = send(cu->cu_sock, cu->cu_outbuf, outlen, 0);
        else
                ret = sendto(cu->cu_sock, cu->cu_outbuf, outlen, 0,
                    (struct sockaddr *)&(cu->cu_raddr), cu->cu_rlen);
        if (ret != outlen) {
                cu->cu_error.re_errno = errno;
                return (cu->cu_error.re_status = RPC_CANTSEND);
        }

        /*
         * Hack to provide rpc-based message passing
         */
        if (!timespecisset(&timeout))
                return (cu->cu_error.re_status = RPC_TIMEDOUT);

        /*
         * 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;
        reply_msg.acpted_rply.ar_results.where = resultsp;
        reply_msg.acpted_rply.ar_results.proc = xresults;

        WRAP(clock_gettime)(CLOCK_MONOTONIC, &start);
        for (;;) {
                switch (ppoll(pfd, 1, &wait, NULL)) {
                case 0:
                        timespecadd(&time_waited, &wait, &time_waited);
                        if (timespeccmp(&time_waited, &timeout, <))
                                goto send_again;
                        return (cu->cu_error.re_status = RPC_TIMEDOUT);
                case 1:
                        if (pfd[0].revents & POLLNVAL)
                                errno = EBADF;
                        else if (pfd[0].revents & POLLERR)
                                errno = EIO;
                        else
                                break;
                        /* FALLTHROUGH */
                case -1:
                        if (errno == EINTR) {
                                WRAP(clock_gettime)(CLOCK_MONOTONIC, &after);
                                timespecsub(&after, &start, &duration);
                                timespecadd(&time_waited, &duration, &time_waited);
                                if (timespeccmp(&time_waited, &timeout, <))
                                        continue;
                                return (cu->cu_error.re_status = RPC_TIMEDOUT);
                        }
                        cu->cu_error.re_errno = errno;
                        return (cu->cu_error.re_status = RPC_CANTRECV);
                }

                do {
                        fromlen = sizeof(struct sockaddr);
                        if (cu->cu_connected) {
                                inlen = recv(cu->cu_sock, cu->cu_inbuf, 
                                    (int) cu->cu_recvsz, 0);
                        } else {

                                inlen = recvfrom(cu->cu_sock, cu->cu_inbuf, 
                                    (int) cu->cu_recvsz, 0,
                                    (struct sockaddr *)&from, &fromlen);
                        }
                } while (inlen == -1 && errno == EINTR);
                if (inlen == -1) {
                        if (errno == EWOULDBLOCK)
                                continue;
                        cu->cu_error.re_errno = errno;
                        return (cu->cu_error.re_status = RPC_CANTRECV);
                }
                if (inlen < sizeof(u_int32_t))
                        continue;       
                /* see if reply transaction id matches sent id */
                if (((struct rpc_msg *)(cu->cu_inbuf))->rm_xid !=
                    ((struct rpc_msg *)(cu->cu_outbuf))->rm_xid)
                        continue;
                /* we now assume we have the proper reply */
                break;
        }

        /*
         * now decode and validate the response
         */
        xdrmem_create(&reply_xdrs, cu->cu_inbuf, (u_int)inlen, XDR_DECODE);
        ok = xdr_replymsg(&reply_xdrs, &reply_msg);
        /* XDR_DESTROY(&reply_xdrs);  save a few cycles on noop destroy */
        if (ok) {
#if 0
                /*
                 * XXX Would like to check these, but call_msg is not
                 * around.
                 */
                if (reply_msg.rm_call.cb_prog != call_msg.rm_call.cb_prog ||
                    reply_msg.rm_call.cb_vers != call_msg.rm_call.cb_vers ||
                    reply_msg.rm_call.cb_proc != call_msg.rm_call.cb_proc) {
                        goto call_again;        /* XXX spin? */
                }
#endif

                _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)) {
                                cu->cu_error.re_status = RPC_AUTHERROR;
                                cu->cu_error.re_why = AUTH_INVALIDRESP;
                        }
                        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));
                        } 
                } else {
                        /* maybe our credentials need to be refreshed ... */
                        if (nrefreshes > 0 && AUTH_REFRESH(cl->cl_auth)) {
                                nrefreshes--;
                                goto call_again;
                        }
                }
        } else {
                /* xdr_replymsg() may have left some things allocated */
                int op = reply_xdrs.x_op;
                reply_xdrs.x_op = XDR_FREE;
                xdr_replymsg(&reply_xdrs, &reply_msg);
                reply_xdrs.x_op = op;
                cu->cu_error.re_status = RPC_CANTDECODERES;
        }

        return (cu->cu_error.re_status);
}

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

        *errp = cu->cu_error;
}


static bool_t
clntudp_freeres(CLIENT *cl, xdrproc_t xdr_res, caddr_t res_ptr)
{
        struct cu_data *cu = (struct cu_data *)cl->cl_private;
        XDR *xdrs = &(cu->cu_outxdrs);

        xdrs->x_op = XDR_FREE;
        return ((*xdr_res)(xdrs, res_ptr));
}

static void 
clntudp_abort(CLIENT *clnt)
{
}

static bool_t
clntudp_control(CLIENT *cl, u_int request, void *info)
{
        struct cu_data *cu = (struct cu_data *)cl->cl_private;

        switch (request) {
        case CLSET_TIMEOUT:
                cu->cu_total = *(struct timeval *)info;
                break;
        case CLGET_TIMEOUT:
                *(struct timeval *)info = cu->cu_total;
                break;
        case CLSET_RETRY_TIMEOUT:
                cu->cu_wait = *(struct timeval *)info;
                break;
        case CLGET_RETRY_TIMEOUT:
                *(struct timeval *)info = cu->cu_wait;
                break;
        case CLGET_SERVER_ADDR:
                *(struct sockaddr_in *)info = cu->cu_raddr;
                break;
        case CLSET_CONNECTED:
                cu->cu_connected = *(int *)info;
                break;
        default:
                return (FALSE);
        }
        return (TRUE);
}
        
static void
clntudp_destroy(CLIENT *cl)
{
        struct cu_data *cu = (struct cu_data *)cl->cl_private;

        if (cu->cu_closeit && cu->cu_sock != -1) {
                (void)close(cu->cu_sock);
        }
        XDR_DESTROY(&(cu->cu_outxdrs));
        mem_free((caddr_t)cu, (sizeof(*cu) + cu->cu_sendsz + cu->cu_recvsz));
        mem_free((caddr_t)cl, sizeof(CLIENT));
}