source: rtems/cpukit/librpc/src/rpc/clnt_udp.c @ d422a4d8

/*
 * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
 * unrestricted use provided that this legend is included on all tape
 * media and as a part of the software program in whole or part.  Users
 * may copy or modify Sun RPC without charge, but are not authorized
 * to license or distribute it to anyone else except as part of a product or
 * program developed by the user.
 *
 * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
 * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
 *
 * Sun RPC is provided with no support and without any obligation on the
 * part of Sun Microsystems, Inc. to assist in its use, correction,
 * modification or enhancement.
 *
 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
 * OR ANY PART THEREOF.
 *
 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
 * or profits or other special, indirect and consequential damages, even if
 * Sun has been advised of the possibility of such damages.
 *
 * Sun Microsystems, Inc.
 * 2550 Garcia Avenue
 * Mountain View, California  94043
 */

#if defined(LIBC_SCCS) && !defined(lint)
/*static char *sccsid = "from: @(#)clnt_udp.c 1.39 87/08/11 Copyr 1984 Sun Micro";*/
/*static char *sccsid = "from: @(#)clnt_udp.c   2.2 88/08/01 4.0 RPCSRC";*/
static char *rcsid = "$FreeBSD: src/lib/libc/rpc/clnt_udp.c,v 1.15 2000/01/27 23:06:36 jasone Exp $";
#endif

/*
 * clnt_udp.c, Implements a UDP/IP based, client side RPC.
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <rpc/rpc.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netdb.h>
#include <errno.h>
#include <rpc/pmap_clnt.h>
#include <sys/select.h>

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

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

/*
 * Private data kept per client handle
 */
struct cu_data {
        int                cu_sock;
        bool_t                  cu_closeit;     /* opened by library */
        struct sockaddr_in cu_raddr;
        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_outbuf;
        u_int                   cu_recvsz;      /* recv size */
        char               cu_inbuf[1];
};

/*
 * 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 clients responsibility to close *sockp.
 * 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;  retransmition occurs until the actual
 * rpc call times out.
 *
 * sendsz and recvsz are the maximum allowable packet sizes that can be
 * sent and received.
 */
CLIENT *
clntudp_bufcreate(
        struct sockaddr_in *raddr,
        u_long program,         /* program number */
        u_long version,         /* version number */
        struct timeval wait,
        int *sockp,
        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;
        static uintptr_t disrupt;

        if (disrupt == 0)
                disrupt = (uintptr_t)raddr;

        cl = (CLIENT *)mem_alloc(sizeof(CLIENT));
        if (cl == NULL) {
                (void) fprintf(stderr, "clntudp_create: out of memory\n");
                rpc_createerr.cf_stat = RPC_SYSTEMERROR;
                rpc_createerr.cf_error.re_errno = errno;
                goto fooy;
        }
        sendsz = ((sendsz + 3) / 4) * 4;
        recvsz = ((recvsz + 3) / 4) * 4;
        cu = mem_alloc(sizeof (*cu) + sendsz + recvsz);
        if (cu == NULL) {
                (void) fprintf(stderr, "clntudp_create: out of memory\n");
                rpc_createerr.cf_stat = RPC_SYSTEMERROR;
                rpc_createerr.cf_error.re_errno = errno;
                goto fooy;
        }
        cu->cu_outbuf = &cu->cu_inbuf[recvsz];

        (void)gettimeofday(&now, (struct timezone *)0);
        if (raddr->sin_port == 0) {
                u_short port;
                if ((port =
                    pmap_getport(raddr, program, version, IPPROTO_UDP)) == 0) {
                        goto fooy;
                }
                raddr->sin_port = htons(port);
        }
        cl->cl_ops = &udp_ops;
        cl->cl_private = (caddr_t)cu;
        cu->cu_raddr = *raddr;
        cu->cu_rlen = sizeof (cu->cu_raddr);
        cu->cu_wait = wait;
        cu->cu_total.tv_sec = -1;
        cu->cu_total.tv_usec = -1;
        cu->cu_sendsz = sendsz;
        cu->cu_recvsz = recvsz;
        call_msg.rm_xid = (++disrupt) ^ getpid() ^ now.tv_sec ^ now.tv_usec;
        call_msg.rm_direction = CALL;
        call_msg.rm_call.cb_rpcvers = RPC_MSG_VERSION;
        call_msg.rm_call.cb_prog = program;
        call_msg.rm_call.cb_vers = version;
        xdrmem_create(&(cu->cu_outxdrs), cu->cu_outbuf,
            sendsz, XDR_ENCODE);
        if (! xdr_callhdr(&(cu->cu_outxdrs), &call_msg)) {
                goto fooy;
        }
        cu->cu_xdrpos = XDR_GETPOS(&(cu->cu_outxdrs));
        if (*sockp < 0) {
                int dontblock = 1;

                *sockp = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
                if (*sockp < 0) {
                        rpc_createerr.cf_stat = RPC_SYSTEMERROR;
                        rpc_createerr.cf_error.re_errno = errno;
                        goto fooy;
                }
                /* attempt to bind to priv port */
                (void)bindresvport(*sockp, (struct sockaddr_in *)0);
                /* the sockets rpc controls are non-blocking */
                (void)ioctl(*sockp, FIONBIO, (char *) &dontblock);
                cu->cu_closeit = TRUE;
        } else {
                cu->cu_closeit = FALSE;
        }
        cu->cu_sock = *sockp;
        cl->cl_auth = authnone_create();
        return (cl);
fooy:
        if (cu)
                mem_free((caddr_t)cu, sizeof(*cu) + sendsz + recvsz);
        if (cl)
                mem_free((caddr_t)cl, sizeof(CLIENT));
        return ((CLIENT *)NULL);
}

CLIENT *
clntudp_create(
        struct sockaddr_in *raddr,
        u_long program,         /* program number */
        u_long version,         /* version number */
        struct timeval wait,
        int *sockp)
{

        return(clntudp_bufcreate(raddr, program, version, wait, sockp,
            UDPMSGSIZE, UDPMSGSIZE));
}

static enum clnt_stat
clntudp_call(
        CLIENT  *cl,                    /* client handle */
        rpcproc_t       proc,           /* procedure number */
        xdrproc_t       xargs,          /* xdr routine for args */
        void            *argsp,         /* pointer to args */
        xdrproc_t       xresults,       /* xdr routine for results */
        void            *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;
        size_t outlen = 0;
        int inlen;
        socklen_t fromlen;
        fd_set *fds, readfds;
        struct sockaddr_in from;
        struct rpc_msg reply_msg;
        XDR reply_xdrs;
        struct timeval time_waited, start, after, tmp1, tmp2, tv;
        bool_t ok;
        int nrefreshes = 2;     /* number of times to refresh cred */
        struct timeval timeout;

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

        if (cu->cu_sock + 1 > FD_SETSIZE) {
                int bytes = howmany(cu->cu_sock + 1, NFDBITS) * sizeof(fd_mask);
                fds = (fd_set *)malloc(bytes);
                if (fds == NULL)
                        return (cu->cu_error.re_status = RPC_CANTSEND);
                memset(fds, 0, bytes);
        } else {
                fds = &readfds;
                FD_ZERO(fds);
        }

        timerclear(&time_waited);

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))) {
                if (fds != &readfds)
                        free(fds);
                return (cu->cu_error.re_status = RPC_CANTENCODEARGS);
        }
        outlen = (size_t)XDR_GETPOS(xdrs);

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

        /*
         * Hack to provide rpc-based message passing
         */
        if (!timerisset(&timeout)) {
                if (fds != &readfds)
                        free(fds);
                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;

        gettimeofday(&start, NULL);
        for (;;) {
                /* XXX we know the other bits are still clear */
                FD_SET(cu->cu_sock, fds);
                tv = cu->cu_wait;
                switch (select(cu->cu_sock+1, fds, NULL, NULL, &tv)) {

                case 0:
                        timeradd(&time_waited, &cu->cu_wait, &tmp1);
                        time_waited = tmp1;
                        if (timercmp(&time_waited, &timeout, <))
                                goto send_again;
                        if (fds != &readfds)
                                free(fds);
                        return (cu->cu_error.re_status = RPC_TIMEDOUT);

                case -1:
                        if (errno == EINTR) {
                                gettimeofday(&after, NULL);
                                timersub(&after, &start, &tmp1);
                                timeradd(&time_waited, &tmp1, &tmp2);
                                time_waited = tmp2;
                                if (timercmp(&time_waited, &timeout, <))
                                        continue;
                                if (fds != &readfds)
                                        free(fds);
                                return (cu->cu_error.re_status = RPC_TIMEDOUT);
                        }
                        cu->cu_error.re_errno = errno;
                        if (fds != &readfds)
                                free(fds);
                        return (cu->cu_error.re_status = RPC_CANTRECV);
                }

                do {
                        fromlen = sizeof(struct sockaddr);
                        inlen = recvfrom(cu->cu_sock, cu->cu_inbuf,
                                (int) cu->cu_recvsz, 0,
                                (struct sockaddr *)&from, &fromlen);
                } while (inlen < 0 && errno == EINTR);
                if (inlen < 0) {
                        if (errno == EWOULDBLOCK)
                                continue;
                        cu->cu_error.re_errno = errno;
                        if (fds != &readfds)
                                free(fds);
                        return (cu->cu_error.re_status = RPC_CANTRECV);
                }
                if (inlen < sizeof(u_int32_t))
                        continue;
                /* see if reply transaction id matches sent id */
                if (*((u_int32_t *)(cu->cu_inbuf)) != *((u_int32_t *)(cu->cu_outbuf)))
                        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) {
                _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));
                        }
                }  /* end successful completion */
                else {
                        /* maybe our credentials need to be refreshed ... */
                        if (nrefreshes > 0 && AUTH_REFRESH(cl->cl_auth)) {
                                nrefreshes--;
                                goto call_again;
                        }
                }  /* end of unsuccessful completion */
        }  /* end of valid reply message */
        else {
                /*
                 * It's possible for xdr_replymsg() to fail partway
                 * through its attempt to decode the result from the
                 * server. If this happens, it will leave the reply
                 * structure partially populated with dynamically
                 * allocated memory. (This can happen if someone uses
                 * clntudp_bufcreate() to create a CLIENT handle and
                 * specifies a receive buffer size that is too small.)
                 * This memory must be free()ed to avoid a leak.
                 */
                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;
        }
        if (fds != &readfds)
                free(fds);
        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,
        void *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(void)
{
}


static bool_t
clntudp_control(
        CLIENT *cl,
        int request,
        char *info)
{
        struct cu_data *cu = (struct cu_data *)cl->cl_private;
        struct timeval *tv;
        socklen_t len;

        switch (request) {
        case CLSET_FD_CLOSE:
                cu->cu_closeit = TRUE;
                break;
        case CLSET_FD_NCLOSE:
                cu->cu_closeit = FALSE;
                break;
        case CLSET_TIMEOUT:
                if (info == NULL)
                        return(FALSE);
                tv = (struct timeval *)info;
                cu->cu_total.tv_sec = tv->tv_sec;
                cu->cu_total.tv_usec = tv->tv_usec;
                break;
        case CLGET_TIMEOUT:
                if (info == NULL)
                        return(FALSE);
                *(struct timeval *)info = cu->cu_total;
                break;
        case CLSET_RETRY_TIMEOUT:
                if (info == NULL)
                        return(FALSE);
                tv = (struct timeval *)info;
                cu->cu_wait.tv_sec = tv->tv_sec;
                cu->cu_wait.tv_usec = tv->tv_usec;
                break;
        case CLGET_RETRY_TIMEOUT:
                if (info == NULL)
                        return(FALSE);
                *(struct timeval *)info = cu->cu_wait;
                break;
        case CLGET_SERVER_ADDR:
                if (info == NULL)
                        return(FALSE);
                *(struct sockaddr_in *)info = cu->cu_raddr;
                break;
        case CLGET_FD:
                if (info == NULL)
                        return(FALSE);
                *(int *)info = cu->cu_sock;
                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
                 */
                if (info == NULL)
                        return(FALSE);
                *(u_long *)info = ntohl(*(u_long *)cu->cu_outbuf);
                break;
        case CLSET_XID:
                /* This will set the xid of the NEXT call */
                if (info == NULL)
                        return(FALSE);
                *(u_long *)cu->cu_outbuf =  htonl(*(u_long *)info - 1);
                /* decrement by 1 as clntudp_call() increments once */
        case CLGET_VERS:
                /*
                 * This RELIES on the information that, in the call body,
                 * the version number field is the fifth field from the
                 * begining of the RPC header. MUST be changed if the
                 * call_struct is changed
                 */
                if (info == NULL)
                        return(FALSE);
                *(u_long *)info = ntohl(*(u_long *)(cu->cu_outbuf +
                                                4 * BYTES_PER_XDR_UNIT));
                break;
        case CLSET_VERS:
                if (info == NULL)
                        return(FALSE);
                *(u_long *)(cu->cu_outbuf + 4 * BYTES_PER_XDR_UNIT)
                                = htonl(*(u_long *)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
                 * begining of the RPC header. MUST be changed if the
                 * call_struct is changed
                 */
                if (info == NULL)
                        return(FALSE);
                *(u_long *)info = ntohl(*(u_long *)(cu->cu_outbuf +
                                                3 * BYTES_PER_XDR_UNIT));
                break;
        case CLSET_PROG:
                if (info == NULL)
                        return(FALSE);
                *(u_long *)(cu->cu_outbuf + 3 * BYTES_PER_XDR_UNIT)
                                = htonl(*(u_long *)info);
                break;
        case CLGET_LOCAL_ADDR:
                len = sizeof(struct sockaddr);
                if (getsockname(cu->cu_sock, (struct sockaddr *)info, &len) <0)
                        return(FALSE);
                break;
        case CLGET_SVC_ADDR:
        case CLSET_SVC_ADDR:
        case CLSET_PUSH_TIMOD:
        case CLSET_POP_TIMOD:
        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) {
                (void)_RPC_close(cu->cu_sock);
        }
        XDR_DESTROY(&(cu->cu_outxdrs));
        mem_free(cu, (sizeof (*cu) + cu->cu_sendsz + cu->cu_recvsz));
        mem_free(cl, sizeof (CLIENT));
}