source: rtems/cpukit/librpc/src/rpc/svc_tcp.c @ 12c21c8

/*
 * 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: @(#)svc_tcp.c 1.21 87/08/11 Copyr 1984 Sun Micro";*/
/*static char *sccsid = "from: @(#)svc_tcp.c    2.2 88/08/01 4.0 RPCSRC";*/
static char *rcsid = "$FreeBSD: src/lib/libc/rpc/svc_tcp.c,v 1.18 2000/01/27 23:06:41 jasone Exp $";
#endif

/*
 * svc_tcp.c, Server side for TCP/IP based RPC.
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 *
 * Actually implements two flavors of transporter -
 * a tcp rendezvouser (a listner and connection establisher)
 * and a record/tcp stream.
 */

#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 <errno.h>
#include <sys/select.h>

/*
 * Ops vector for TCP/IP based rpc service handle
 */
static bool_t           svctcp_recv(SVCXPRT *xprt, struct rpc_msg *msg);
static enum xprt_stat   svctcp_stat(SVCXPRT *xprt);
static bool_t           svctcp_getargs(SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr);
static bool_t           svctcp_reply(SVCXPRT *xprt, struct rpc_msg *msg);
static bool_t           svctcp_freeargs(SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr);
static void             svctcp_destroy(SVCXPRT *xprt);

static struct xp_ops svctcp_op = {
        svctcp_recv,
        svctcp_stat,
        svctcp_getargs,
        svctcp_reply,
        svctcp_freeargs,
        svctcp_destroy
};

/*
 * Ops vector for TCP/IP rendezvous handler
 */
static bool_t           rendezvous_request(SVCXPRT *xprt, struct rpc_msg *msg);
static enum xprt_stat   rendezvous_stat(SVCXPRT *xprt);

static struct xp_ops svctcp_rendezvous_op = {
        rendezvous_request,
        rendezvous_stat,
        (bool_t (*)(SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr))abort,
        (bool_t (*)(SVCXPRT *xprt, struct rpc_msg *msg))abort,
        (bool_t (*)(SVCXPRT *xprt, xdrproc_t xdr_args, caddr_t args_ptr))abort,
        svctcp_destroy
};

static int readtcp(), writetcp();
static SVCXPRT *makefd_xprt();

struct tcp_rendezvous { /* kept in xprt->xp_p1 */
        u_int sendsize;
        u_int recvsize;
};

struct tcp_conn {  /* kept in xprt->xp_p1 */
        enum xprt_stat strm_stat;
        u_long x_id;
        XDR xdrs;
        char verf_body[MAX_AUTH_BYTES];
};

/*
 * Usage:
 *      xprt = svctcp_create(sock, send_buf_size, recv_buf_size);
 *
 * Creates, registers, and returns a (rpc) tcp based transporter.
 * Once *xprt is initialized, it is registered as a transporter
 * see (svc.h, xprt_register).  This routine returns
 * a NULL if a problem occurred.
 *
 * If sock<0 then a socket is created, else sock is used.
 * If the socket, sock is not bound to a port then svctcp_create
 * binds it to an arbitrary port.  The routine then starts a tcp
 * listener on the socket's associated port.  In any (successful) case,
 * xprt->xp_sock is the registered socket number and xprt->xp_port is the
 * associated port number.
 *
 * Since tcp streams do buffered io similar to stdio, the caller can specify
 * how big the send and receive buffers are via the second and third parms;
 * 0 => use the system default.
 */
SVCXPRT *
svctcp_create(
        int sock,
        u_int sendsize,
        u_int recvsize)
{
        bool_t madesock = FALSE;
        register SVCXPRT *xprt;
        register struct tcp_rendezvous *r;
        struct sockaddr_in addr;
        socklen_t len = sizeof(struct sockaddr_in);
        int on;

        if (sock == RPC_ANYSOCK) {
                if ((sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
                        perror("svctcp_.c - udp socket creation problem");
                        return ((SVCXPRT *)NULL);
                }
                madesock = TRUE;
        }
        on = 1;
        if (ioctl(sock, FIONBIO, &on) < 0) {
                perror("svc_tcp.c - cannot turn on non-blocking mode");
                if (madesock)
                       (void)_RPC_close(sock);
                return ((SVCXPRT *)NULL);
        }
        memset(&addr, 0, sizeof (addr));
        addr.sin_len = sizeof(struct sockaddr_in);
        addr.sin_family = AF_INET;
        if (bindresvport(sock, &addr)) {
                addr.sin_port = 0;
                (void)bind(sock, (struct sockaddr *)&addr, len);
        }
        if ((getsockname(sock, (struct sockaddr *)&addr, &len) != 0)  ||
            (listen(sock, 2) != 0)) {
                perror("svctcp_.c - cannot getsockname or listen");
                if (madesock)
                       (void)_RPC_close(sock);
                return ((SVCXPRT *)NULL);
        }
        r = (struct tcp_rendezvous *)mem_alloc(sizeof(*r));
        if (r == NULL) {
                (void) fprintf(stderr, "svctcp_create: out of memory\n");
                return (NULL);
        }
        r->sendsize = sendsize;
        r->recvsize = recvsize;
        xprt = (SVCXPRT *)mem_alloc(sizeof(SVCXPRT));
        if (xprt == NULL) {
                (void) fprintf(stderr, "svctcp_create: out of memory\n");
                return (NULL);
        }
        xprt->xp_p2 = NULL;
        xprt->xp_p1 = (caddr_t)r;
        xprt->xp_verf = _null_auth;
        xprt->xp_ops = &svctcp_rendezvous_op;
        xprt->xp_port = ntohs(addr.sin_port);
        xprt->xp_sock = sock;
        xprt_register(xprt);
        return (xprt);
}

/*
 * Like svtcp_create(), except the routine takes any *open* UNIX file
 * descriptor as its first input.
 */
SVCXPRT *
svcfd_create(
        int fd,
        u_int sendsize,
        u_int recvsize)
{

        return (makefd_xprt(fd, sendsize, recvsize));
}

static SVCXPRT *
makefd_xprt(
        int fd,
        u_int sendsize,
        u_int recvsize)
{
        register SVCXPRT *xprt;
        register struct tcp_conn *cd;

        xprt = (SVCXPRT *)mem_alloc(sizeof(SVCXPRT));
        if (xprt == (SVCXPRT *)NULL) {
                (void) fprintf(stderr, "svc_tcp: makefd_xprt: out of memory\n");
                goto done;
        }
        cd = (struct tcp_conn *)mem_alloc(sizeof(struct tcp_conn));
        if (cd == (struct tcp_conn *)NULL) {
                (void) fprintf(stderr, "svc_tcp: makefd_xprt: out of memory\n");
                mem_free((char *) xprt, sizeof(SVCXPRT));
                xprt = (SVCXPRT *)NULL;
                goto done;
        }
        cd->strm_stat = XPRT_IDLE;
        xdrrec_create(&(cd->xdrs), sendsize, recvsize,
            (caddr_t)xprt, readtcp, writetcp);
        xprt->xp_p2 = NULL;
        xprt->xp_p1 = (caddr_t)cd;
        xprt->xp_verf.oa_base = cd->verf_body;
        xprt->xp_addrlen = 0;
        xprt->xp_ops = &svctcp_op;  /* truely deals with calls */
        xprt->xp_port = 0;  /* this is a connection, not a rendezvouser */
        xprt->xp_sock = fd;
        xprt_register(xprt);
    done:
        return (xprt);
}

static bool_t
rendezvous_request(
        SVCXPRT *xprt,
        struct rpc_msg *msg)
{
        int sock;
        struct tcp_rendezvous *r;
        struct sockaddr_in addr;
        socklen_t len;
        int off;

        r = (struct tcp_rendezvous *)xprt->xp_p1;
    again:
        len = sizeof(struct sockaddr_in);
        if ((sock = accept(xprt->xp_sock, (struct sockaddr *)&addr,
            &len)) < 0) {
                if (errno == EINTR)
                        goto again;
               return (FALSE);
        }
        /*
         * Guard against FTP bounce attacks.
         */
        if (addr.sin_port == htons(20)) {
                _RPC_close(sock);
                return (FALSE);
        }
        /*
         * The listening socket is in FIONBIO mode and we inherit it.
         */
        off = 0;
        if (ioctl(sock, FIONBIO, &off) < 0) {
                _RPC_close(sock);
                return (FALSE);
        }
        /*
         * make a new transporter (re-uses xprt)
         */
        xprt = makefd_xprt(sock, r->sendsize, r->recvsize);
        xprt->xp_raddr = addr;
        xprt->xp_addrlen = len;
        return (FALSE); /* there is never an rpc msg to be processed */
}

static enum xprt_stat
rendezvous_stat(SVCXPRT *xprt)
{

        return (XPRT_IDLE);
}

static void
svctcp_destroy(
        SVCXPRT *xprt)
{
        register struct tcp_conn *cd = (struct tcp_conn *)xprt->xp_p1;

        xprt_unregister(xprt);
        (void)_RPC_close(xprt->xp_sock);
        if (xprt->xp_port != 0) {
                /* a rendezvouser socket */
                xprt->xp_port = 0;
        } else {
                /* an actual connection socket */
                XDR_DESTROY(&(cd->xdrs));
        }
        mem_free((caddr_t)cd, sizeof(struct tcp_conn));
        mem_free((caddr_t)xprt, sizeof(SVCXPRT));
}

/*
 * All read operations timeout after 35 seconds.
 * A timeout is fatal for the connection.
 */
static struct timeval wait_per_try = { 35, 0 };

/*
 * reads data from the tcp conection.
 * any error is fatal and the connection is closed.
 * (And a read of zero bytes is a half closed stream => error.)
 *
 * Note: we have to be careful here not to allow ourselves to become
 * blocked too long in this routine. While we're waiting for data from one
 * client, another client may be trying to connect. To avoid this situation,
 * some code from svc_run() is transplanted here: the select() loop checks
 * all RPC descriptors including the one we want and calls svc_getreqset2()
 * to handle new requests if any are detected.
 */
static int
readtcp(
        SVCXPRT *xprt,
        caddr_t buf,
        int len)
{
        register int sock = xprt->xp_sock;
        struct timeval start, delta, tv;
        struct timeval tmp1, tmp2;
        fd_set *fds;

        delta = wait_per_try;
        fds = NULL;
        gettimeofday(&start, NULL);
        do {
                int bytes = sizeof (fd_set);
                if (fds != NULL)
                        free(fds);
                fds = (fd_set *)malloc(bytes);
                if (fds == NULL)
                        goto fatal_err;
                memcpy(fds, __svc_fdset, bytes);

                /* XXX we know the other bits are still clear */
                FD_SET(sock, fds);
                tv = delta;     /* in case select() implements writeback */
                switch (select(svc_maxfd + 1, fds, NULL, NULL, &tv)) {
                case -1:
                        if (errno != EINTR)
                                goto fatal_err;
                        gettimeofday(&tmp1, NULL);
                        timersub(&tmp1, &start, &tmp2);
                        timersub(&wait_per_try, &tmp2, &tmp1);
                        if (tmp1.tv_sec < 0 || !timerisset(&tmp1))
                                goto fatal_err;
                        delta = tmp1;
                        continue;
                case 0:
                        goto fatal_err;
                default:
                        if (!FD_ISSET(sock, fds)) {
                                svc_getreqset2(fds, svc_maxfd + 1);
                                gettimeofday(&tmp1, NULL);
                                timersub(&tmp1, &start, &tmp2);
                                timersub(&wait_per_try, &tmp2, &tmp1);
                                if (tmp1.tv_sec < 0 || !timerisset(&tmp1))
                                        goto fatal_err;
                                delta = tmp1;
                                continue;
                        }
                }
        } while (!FD_ISSET(sock, fds));
        if ((len = _RPC_read(sock, buf, len)) > 0) {
                if (fds != NULL)
                        free(fds);
                return (len);
        }
fatal_err:
        ((struct tcp_conn *)(xprt->xp_p1))->strm_stat = XPRT_DIED;
        if (fds != NULL)
                free(fds);
        return (-1);
}

/*
 * writes data to the tcp connection.
 * Any error is fatal and the connection is closed.
 */
static int
writetcp(
        SVCXPRT *xprt,
        caddr_t buf,
        int len)
{
        register int i, cnt;

        for (cnt = len; cnt > 0; cnt -= i, buf += i) {
                if ((i = _RPC_write(xprt->xp_sock, buf, cnt)) < 0) {
                        ((struct tcp_conn *)(xprt->xp_p1))->strm_stat =
                            XPRT_DIED;
                        return (-1);
                }
        }
        return (len);
}

static enum xprt_stat
svctcp_stat(
        SVCXPRT *xprt)
{
        register struct tcp_conn *cd =
            (struct tcp_conn *)(xprt->xp_p1);

        if (cd->strm_stat == XPRT_DIED)
                return (XPRT_DIED);
        if (! xdrrec_eof(&(cd->xdrs)))
                return (XPRT_MOREREQS);
        return (XPRT_IDLE);
}

static bool_t
svctcp_recv(
        SVCXPRT *xprt,
        struct rpc_msg *msg)
{
        register struct tcp_conn *cd =
            (struct tcp_conn *)(xprt->xp_p1);
        register XDR *xdrs = &(cd->xdrs);

        xdrs->x_op = XDR_DECODE;
        (void)xdrrec_skiprecord(xdrs);
        if (xdr_callmsg(xdrs, msg)) {
                cd->x_id = msg->rm_xid;
                return (TRUE);
        }
        cd->strm_stat = XPRT_DIED;      /* XXXX */
        return (FALSE);
}

static bool_t
svctcp_getargs(
        SVCXPRT *xprt,
        xdrproc_t xdr_args,
        caddr_t args_ptr)
{

        return ((*xdr_args)(&(((struct tcp_conn *)(xprt->xp_p1))->xdrs), args_ptr));
}

static bool_t
svctcp_freeargs(
        SVCXPRT *xprt,
        xdrproc_t xdr_args,
        caddr_t args_ptr)
{
        register XDR *xdrs =
            &(((struct tcp_conn *)(xprt->xp_p1))->xdrs);

        xdrs->x_op = XDR_FREE;
        return ((*xdr_args)(xdrs, args_ptr));
}

static bool_t
svctcp_reply(
        SVCXPRT *xprt,
        struct rpc_msg *msg)
{
        register struct tcp_conn *cd =
            (struct tcp_conn *)(xprt->xp_p1);
        register XDR *xdrs = &(cd->xdrs);
        register bool_t stat;

        xdrs->x_op = XDR_ENCODE;
        msg->rm_xid = cd->x_id;
        stat = xdr_replymsg(xdrs, msg);
        (void)xdrrec_endofrecord(xdrs, TRUE);
        return (stat);
}