/*      $NetBSD: svc.c,v 1.21 2000/07/06 03:10:35 christos 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.
 */

/*
 * svc.c, Server-side remote procedure call interface.
 *
 * There are two sets of procedures here.  The xprt routines are
 * for handling transport handles.  The svc routines handle the
 * list of service routines.
 *
 * Copyright (C) 1984, Sun Microsystems, Inc.
 */

#include "namespace.h"
#include "reentrant.h"
#include <sys/types.h>
#include <sys/poll.h>
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>

#include <rpc/rpc.h>
#ifdef PORTMAP
#include <rpc/pmap_clnt.h>
#endif                          /* PORTMAP */
#include "un-namespace.h"

#include "rpc_com.h"
#include "mt_misc.h"

#define RQCRED_SIZE     400             /* this size is excessive */

#define SVC_VERSQUIET 0x0001            /* keep quiet about vers mismatch */
#define version_keepquiet(xp) (SVC_EXT(xp)->xp_flags & SVC_VERSQUIET)

#define max(a, b) (a > b ? a : b)

/*
 * The services list
 * Each entry represents a set of procedures (an rpc program).
 * The dispatch routine takes request structs and runs the
 * appropriate procedure.
 */
static struct svc_callout {
        struct svc_callout *sc_next;
        rpcprog_t           sc_prog;
        rpcvers_t           sc_vers;
        char               *sc_netid;
        void                (*sc_dispatch)(struct svc_req *, SVCXPRT *);
} *svc_head;

SVCXPRT **__svc_xports;
int __svc_maxrec;

static struct svc_callout *svc_find(rpcprog_t, rpcvers_t,
    struct svc_callout **, char *);
static void __xprt_do_unregister (SVCXPRT *xprt, bool_t dolock);

/* ***************  SVCXPRT related stuff **************** */

/*
 * Activate a transport handle.
 */
void
xprt_register(SVCXPRT *xprt)
{
        int sock;

        assert(xprt != NULL);

        sock = xprt->xp_fd;

        rwlock_wrlock(&svc_fd_lock);
        if (__svc_xports == NULL) {
                __svc_xports = (SVCXPRT **)
                        mem_alloc((FD_SETSIZE + 1) * sizeof(SVCXPRT *));
                if (__svc_xports == NULL) {
                        rwlock_unlock(&svc_fd_lock);
                        return;
                }
                memset(__svc_xports, '\0', (FD_SETSIZE + 1) * sizeof(SVCXPRT *));
        }
        if (sock < FD_SETSIZE) {
                __svc_xports[sock] = xprt;
                FD_SET(sock, &svc_fdset);
                svc_maxfd = max(svc_maxfd, sock);
        } else if (sock == FD_SETSIZE)
                __svc_xports[sock] = xprt;
        rwlock_unlock(&svc_fd_lock);
}

void
xprt_unregister(SVCXPRT *xprt)
{
        __xprt_do_unregister(xprt, TRUE);
}

void
__xprt_unregister_unlocked(SVCXPRT *xprt)
{
        __xprt_do_unregister(xprt, FALSE);
}

/*
 * De-activate a transport handle.
 */
static void
__xprt_do_unregister(SVCXPRT *xprt, bool_t dolock)
{
        int sock;

        assert(xprt != NULL);

        sock = xprt->xp_fd;

        if (dolock)
                rwlock_wrlock(&svc_fd_lock);
        if ((sock < FD_SETSIZE) && (__svc_xports[sock] == xprt)) {
                __svc_xports[sock] = NULL;
                FD_CLR(sock, &svc_fdset);
                if (sock >= svc_maxfd) {
                        for (svc_maxfd--; svc_maxfd>=0; svc_maxfd--)
                                if (__svc_xports[svc_maxfd])
                                        break;
                }
        } else if ((sock == FD_SETSIZE) && (__svc_xports[sock] == xprt))
                __svc_xports[sock] = NULL;
        if (dolock)
                rwlock_unlock(&svc_fd_lock);
}

/*
 * Add a service program to the callout list.
 * The dispatch routine will be called when a rpc request for this
 * program number comes in.
 */
bool_t
svc_reg(SVCXPRT *xprt, const rpcprog_t prog, const rpcvers_t vers,
    void (*dispatch)(struct svc_req *, SVCXPRT *),
    const struct netconfig *nconf)
{
        bool_t dummy;
        struct svc_callout *prev;
        struct svc_callout *s;
        struct netconfig *tnconf;
        char *netid = NULL;
        int flag = 0;

/* VARIABLES PROTECTED BY svc_lock: s, prev, svc_head */

        if (xprt->xp_netid) {
                netid = strdup(xprt->xp_netid);
                flag = 1;
        } else if (nconf && nconf->nc_netid) {
                netid = strdup(nconf->nc_netid);
                flag = 1;
        } else if ((tnconf = __rpcgettp(xprt->xp_fd)) != NULL) {
                netid = strdup(tnconf->nc_netid);
                flag = 1;
                freenetconfigent(tnconf);
        } /* must have been created with svc_raw_create */
        if ((netid == NULL) && (flag == 1)) {
                return (FALSE);
        }

        rwlock_wrlock(&svc_lock);
        if ((s = svc_find(prog, vers, &prev, netid)) != NULL) {
                free(netid);
                if (s->sc_dispatch == dispatch)
                        goto rpcb_it; /* he is registering another xptr */
                rwlock_unlock(&svc_lock);
                return (FALSE);
        }
        s = mem_alloc(sizeof (struct svc_callout));
        if (s == NULL) {
                free(netid);
                rwlock_unlock(&svc_lock);
                return (FALSE);
        }

        s->sc_prog = prog;
        s->sc_vers = vers;
        s->sc_dispatch = dispatch;
        s->sc_netid = netid;
        s->sc_next = svc_head;
        svc_head = s;

        if ((xprt->xp_netid == NULL) && (flag == 1) && netid)
                ((SVCXPRT *) xprt)->xp_netid = strdup(netid);

rpcb_it:
        rwlock_unlock(&svc_lock);
        /* now register the information with the local binder service */
        if (nconf) {
                /*LINTED const castaway*/
                dummy = rpcb_set(prog, vers, (struct netconfig *) nconf,
                &((SVCXPRT *) xprt)->xp_ltaddr);
                return (dummy);
        }
        return (TRUE);
}

/*
 * Remove a service program from the callout list.
 */
void
svc_unreg(const rpcprog_t prog, const rpcvers_t vers)
{
        struct svc_callout *prev;
        struct svc_callout *s;

        /* unregister the information anyway */
        (void) rpcb_unset(prog, vers, NULL);
        rwlock_wrlock(&svc_lock);
        while ((s = svc_find(prog, vers, &prev, NULL)) != NULL) {
                if (prev == NULL) {
                        svc_head = s->sc_next;
                } else {
                        prev->sc_next = s->sc_next;
                }
                s->sc_next = NULL;
                if (s->sc_netid)
                        mem_free(s->sc_netid, sizeof (s->sc_netid) + 1);
                mem_free(s, sizeof (struct svc_callout));
        }
        rwlock_unlock(&svc_lock);
}

/* ********************** CALLOUT list related stuff ************* */

#ifdef PORTMAP
/*
 * Add a service program to the callout list.
 * The dispatch routine will be called when a rpc request for this
 * program number comes in.
 */
bool_t
svc_register(SVCXPRT *xprt, u_long prog, u_long vers,
    void (*dispatch)(struct svc_req *, SVCXPRT *),
    int protocol)
{
        struct svc_callout *prev;
        struct svc_callout *s;

        assert(xprt != NULL);
        assert(dispatch != NULL);

        if ((s = svc_find((rpcprog_t)prog, (rpcvers_t)vers, &prev, NULL)) !=
            NULL) {
                if (s->sc_dispatch == dispatch)
                        goto pmap_it;  /* he is registering another xptr */
                return (FALSE);
        }
        s = mem_alloc(sizeof(struct svc_callout));
        if (s == NULL) {
                return (FALSE);
        }
        s->sc_prog = (rpcprog_t)prog;
        s->sc_vers = (rpcvers_t)vers;
        s->sc_dispatch = dispatch;
        s->sc_next = svc_head;
        svc_head = s;
pmap_it:
        /* now register the information with the local binder service */
        if (protocol) {
                return (pmap_set(prog, vers, protocol, xprt->xp_port));
        }
        return (TRUE);
}

/*
 * Remove a service program from the callout list.
 */
void
svc_unregister(u_long prog, u_long vers)
{
        struct svc_callout *prev;
        struct svc_callout *s;

        if ((s = svc_find((rpcprog_t)prog, (rpcvers_t)vers, &prev, NULL)) ==
            NULL)
                return;
        if (prev == NULL) {
                svc_head = s->sc_next;
        } else {
                prev->sc_next = s->sc_next;
        }
        s->sc_next = NULL;
        mem_free(s, sizeof(struct svc_callout));
        /* now unregister the information with the local binder service */
        (void)pmap_unset(prog, vers);
}
#endif                          /* PORTMAP */

/*
 * Search the callout list for a program number, return the callout
 * struct.
 */
static struct svc_callout *
svc_find(rpcprog_t prog, rpcvers_t vers, struct svc_callout **prev,
    char *netid)
{
        struct svc_callout *s, *p;

        assert(prev != NULL);

        p = NULL;
        for (s = svc_head; s != NULL; s = s->sc_next) {
                if (((s->sc_prog == prog) && (s->sc_vers == vers)) &&
                    ((netid == NULL) || (s->sc_netid == NULL) ||
                    (strcmp(netid, s->sc_netid) == 0)))
                        break;
                p = s;
        }
        *prev = p;
        return (s);
}

/* ******************* REPLY GENERATION ROUTINES  ************ */

/*
 * Send a reply to an rpc request
 */
bool_t
svc_sendreply(SVCXPRT *xprt, xdrproc_t xdr_results,
    void * xdr_location)
{
        struct rpc_msg rply; 

        assert(xprt != NULL);

        rply.rm_direction = REPLY;  
        rply.rm_reply.rp_stat = MSG_ACCEPTED; 
        rply.acpted_rply.ar_verf = xprt->xp_verf; 
        rply.acpted_rply.ar_stat = SUCCESS;
        rply.acpted_rply.ar_results.where = xdr_location;
        rply.acpted_rply.ar_results.proc = xdr_results;
        return (SVC_REPLY(xprt, &rply)); 
}

/*
 * No procedure error reply
 */
void
svcerr_noproc(SVCXPRT *xprt)
{
        struct rpc_msg rply;

        assert(xprt != NULL);

        rply.rm_direction = REPLY;
        rply.rm_reply.rp_stat = MSG_ACCEPTED;
        rply.acpted_rply.ar_verf = xprt->xp_verf;
        rply.acpted_rply.ar_stat = PROC_UNAVAIL;
        SVC_REPLY(xprt, &rply);
}

/*
 * Can't decode args error reply
 */
void
svcerr_decode(SVCXPRT *xprt)
{
        struct rpc_msg rply; 

        assert(xprt != NULL);

        rply.rm_direction = REPLY; 
        rply.rm_reply.rp_stat = MSG_ACCEPTED; 
        rply.acpted_rply.ar_verf = xprt->xp_verf;
        rply.acpted_rply.ar_stat = GARBAGE_ARGS;
        SVC_REPLY(xprt, &rply); 
}

/*
 * Some system error
 */
void
svcerr_systemerr(SVCXPRT *xprt)
{
        struct rpc_msg rply; 

        assert(xprt != NULL);

        rply.rm_direction = REPLY; 
        rply.rm_reply.rp_stat = MSG_ACCEPTED; 
        rply.acpted_rply.ar_verf = xprt->xp_verf;
        rply.acpted_rply.ar_stat = SYSTEM_ERR;
        SVC_REPLY(xprt, &rply); 
}

#if 0
/*
 * Tell RPC package to not complain about version errors to the client.  This
 * is useful when revving broadcast protocols that sit on a fixed address.
 * There is really one (or should be only one) example of this kind of
 * protocol: the portmapper (or rpc binder).
 */
void
__svc_versquiet_on(SVCXPRT *xprt)
{

        SVC_EXT(xprt)->xp_flags |= SVC_VERSQUIET;
}

void
__svc_versquiet_off(SVCXPRT *xprt)
{

        SVC_EXT(xprt)->xp_flags &= ~SVC_VERSQUIET;
}

void
svc_versquiet(SVCXPRT *xprt)
{
        __svc_versquiet_on(xprt);
}

int
__svc_versquiet_get(SVCXPRT *xprt)
{

        return (SVC_EXT(xprt)->xp_flags & SVC_VERSQUIET);
}
#endif

/*
 * Authentication error reply
 */
void
svcerr_auth(SVCXPRT *xprt, enum auth_stat why)
{
        struct rpc_msg rply;

        assert(xprt != NULL);

        rply.rm_direction = REPLY;
        rply.rm_reply.rp_stat = MSG_DENIED;
        rply.rjcted_rply.rj_stat = AUTH_ERROR;
        rply.rjcted_rply.rj_why = why;
        SVC_REPLY(xprt, &rply);
}

/*
 * Auth too weak error reply
 */
void
svcerr_weakauth(SVCXPRT *xprt)
{

        assert(xprt != NULL);

        svcerr_auth(xprt, AUTH_TOOWEAK);
}

/*
 * Program unavailable error reply
 */
void 
svcerr_noprog(SVCXPRT *xprt)
{
        struct rpc_msg rply;  

        assert(xprt != NULL);

        rply.rm_direction = REPLY;   
        rply.rm_reply.rp_stat = MSG_ACCEPTED;  
        rply.acpted_rply.ar_verf = xprt->xp_verf;  
        rply.acpted_rply.ar_stat = PROG_UNAVAIL;
        SVC_REPLY(xprt, &rply);
}

/*
 * Program version mismatch error reply
 */
void  
svcerr_progvers(SVCXPRT *xprt, rpcvers_t low_vers, rpcvers_t high_vers)
{
        struct rpc_msg rply;

        assert(xprt != NULL);

        rply.rm_direction = REPLY;
        rply.rm_reply.rp_stat = MSG_ACCEPTED;
        rply.acpted_rply.ar_verf = xprt->xp_verf;
        rply.acpted_rply.ar_stat = PROG_MISMATCH;
        rply.acpted_rply.ar_vers.low = (u_int32_t)low_vers;
        rply.acpted_rply.ar_vers.high = (u_int32_t)high_vers;
        SVC_REPLY(xprt, &rply);
}

/*
 * Allocate a new server transport structure. All fields are
 * initialized to zero and xp_p3 is initialized to point at an
 * extension structure to hold various flags and authentication
 * parameters.
 */
SVCXPRT *
svc_xprt_alloc(void)
{
        SVCXPRT *xprt;
        SVCXPRT_EXT *ext;

        xprt = mem_alloc(sizeof(SVCXPRT));
        if (xprt == NULL)
                return (NULL);
        memset(xprt, 0, sizeof(SVCXPRT));
        ext = mem_alloc(sizeof(SVCXPRT_EXT));
        if (ext == NULL) {
                mem_free(xprt, sizeof(SVCXPRT));
                return (NULL);
        }
        memset(ext, 0, sizeof(SVCXPRT_EXT));
        xprt->xp_p3 = ext;
        ext->xp_auth.svc_ah_ops = &svc_auth_null_ops;

        return (xprt);
}

/*
 * Free a server transport structure.
 */
void
svc_xprt_free(SVCXPRT *xprt)
{

        mem_free(xprt->xp_p3, sizeof(SVCXPRT_EXT));
        mem_free(xprt, sizeof(SVCXPRT));
}

/* ******************* SERVER INPUT STUFF ******************* */

/*
 * Get server side input from some transport.
 *
 * Statement of authentication parameters management:
 * This function owns and manages all authentication parameters, specifically
 * the "raw" parameters (msg.rm_call.cb_cred and msg.rm_call.cb_verf) and
 * the "cooked" credentials (rqst->rq_clntcred).
 * However, this function does not know the structure of the cooked
 * credentials, so it make the following assumptions:
 *   a) the structure is contiguous (no pointers), and
 *   b) the cred structure size does not exceed RQCRED_SIZE bytes.
 * In all events, all three parameters are freed upon exit from this routine.
 * The storage is trivially management on the call stack in user land, but
 * is mallocated in kernel land.
 */

void
svc_getreq(int rdfds)
{
        fd_set readfds;

        FD_ZERO(&readfds);
        readfds.fds_bits[0] = rdfds;
        svc_getreqset(&readfds);
}

void
svc_getreqset(fd_set *readfds)
{
        int bit, fd;
        fd_mask mask, *maskp;
        int sock;

        assert(readfds != NULL);

        maskp = readfds->fds_bits;
        for (sock = 0; sock < FD_SETSIZE; sock += NFDBITS) {
            for (mask = *maskp++; (bit = ffsl(mask)) != 0;
                mask ^= (1ul << (bit - 1))) {
                /* sock has input waiting */
                fd = sock + bit - 1;
                svc_getreq_common(fd);
            }
        }
}

void
svc_getreq_common(int fd)
{
        SVCXPRT *xprt;
        struct svc_req r;
        struct rpc_msg msg;
        int prog_found;
        rpcvers_t low_vers;
        rpcvers_t high_vers;
        enum xprt_stat stat;
        char cred_area[2*MAX_AUTH_BYTES + RQCRED_SIZE];

        msg.rm_call.cb_cred.oa_base = cred_area;
        msg.rm_call.cb_verf.oa_base = &(cred_area[MAX_AUTH_BYTES]);
        r.rq_clntcred = &(cred_area[2*MAX_AUTH_BYTES]);

        rwlock_rdlock(&svc_fd_lock);
        xprt = __svc_xports[fd];
        rwlock_unlock(&svc_fd_lock);
        if (xprt == NULL)
                /* But do we control sock? */
                return;
        /* now receive msgs from xprtprt (support batch calls) */
        do {
                if (SVC_RECV(xprt, &msg)) {

                        /* now find the exported program and call it */
                        struct svc_callout *s;
                        enum auth_stat why;

                        r.rq_xprt = xprt;
                        r.rq_prog = msg.rm_call.cb_prog;
                        r.rq_vers = msg.rm_call.cb_vers;
                        r.rq_proc = msg.rm_call.cb_proc;
                        r.rq_cred = msg.rm_call.cb_cred;
                        /* first authenticate the message */
                        if ((why = _authenticate(&r, &msg)) != AUTH_OK) {
                                /*
                                 * RPCSEC_GSS uses this return code
                                 * for requests that form part of its
                                 * context establishment protocol and
                                 * should not be dispatched to the
                                 * application.
                                 */
                                if (why != RPCSEC_GSS_NODISPATCH)
                                        svcerr_auth(xprt, why);
                                goto call_done;
                        }
                        /* now match message with a registered service*/
                        prog_found = FALSE;
                        low_vers = (rpcvers_t) -1L;
                        high_vers = (rpcvers_t) 0L;
                        for (s = svc_head; s != NULL; s = s->sc_next) {
                                if (s->sc_prog == r.rq_prog) {
                                        if (s->sc_vers == r.rq_vers) {
                                                (*s->sc_dispatch)(&r, xprt);
                                                goto call_done;
                                        }  /* found correct version */
                                        prog_found = TRUE;
                                        if (s->sc_vers < low_vers)
                                                low_vers = s->sc_vers;
                                        if (s->sc_vers > high_vers)
                                                high_vers = s->sc_vers;
                                }   /* found correct program */
                        }
                        /*
                         * if we got here, the program or version
                         * is not served ...
                         */
                        if (prog_found)
                                svcerr_progvers(xprt, low_vers, high_vers);
                        else
                                svcerr_noprog(xprt);
                        /* Fall through to ... */
                }
                /*
                 * Check if the xprt has been disconnected in a
                 * recursive call in the service dispatch routine.
                 * If so, then break.
                 */
                rwlock_rdlock(&svc_fd_lock);
                if (xprt != __svc_xports[fd]) {
                        rwlock_unlock(&svc_fd_lock);
                        break;
                }
                rwlock_unlock(&svc_fd_lock);
call_done:
                if ((stat = SVC_STAT(xprt)) == XPRT_DIED){
                        SVC_DESTROY(xprt);
                        break;
                }
        } while (stat == XPRT_MOREREQS);
}


void
svc_getreq_poll(struct pollfd *pfdp, int pollretval)
{
        int i;
        int fds_found;

        for (i = fds_found = 0; fds_found < pollretval; i++) {
                struct pollfd *p = &pfdp[i];

                if (p->revents) {
                        /* fd has input waiting */
                        fds_found++;
                        /*
                         *      We assume that this function is only called
                         *      via someone _select()ing from svc_fdset or
                         *      _poll()ing from svc_pollset[].  Thus it's safe
                         *      to handle the POLLNVAL event by simply turning
                         *      the corresponding bit off in svc_fdset.  The
                         *      svc_pollset[] array is derived from svc_fdset
                         *      and so will also be updated eventually.
                         *
                         *      XXX Should we do an xprt_unregister() instead?
                         */
                        if (p->revents & POLLNVAL) {
                                rwlock_wrlock(&svc_fd_lock);
                                FD_CLR(p->fd, &svc_fdset);
                                rwlock_unlock(&svc_fd_lock);
                        } else
                                svc_getreq_common(p->fd);
                }
        }
}

bool_t
rpc_control(int what, void *arg)
{
        int val;

        switch (what) {
        case RPC_SVC_CONNMAXREC_SET:
                val = *(int *)arg;
                if (val <= 0)
                        return FALSE;
                __svc_maxrec = val;
                return TRUE;
        case RPC_SVC_CONNMAXREC_GET:
                *(int *)arg = __svc_maxrec;
                return TRUE;
        default:
                break;
        }
        return FALSE;
}