/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 * Copyright 2002 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
/*
 * Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
 */

/* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

/*
 * check_bound.c
 * Checks to see whether the program is still bound to the
 * claimed address and returns the univeral merged address
 *
 */

#include <stdio.h>
#include <rpc/rpc.h>
#include <netconfig.h>
#include <netdir.h>
#include <sys/syslog.h>
#include <stdlib.h>
#include "rpcbind.h"
#include <string.h>
/* the following just to get my address */
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <thread.h>
#include <synch.h>
#include <syslog.h>

struct fdlist {
        int fd;
        mutex_t fd_lock;        /* protects fd */
        struct netconfig *nconf;
        struct fdlist *next;
        int check_binding;
};

static struct fdlist *fdhead;   /* Link list of the check fd's */
static struct fdlist *fdtail;
static char *nullstring = "";

/*
 * Returns 1 if the given address is bound for the given addr & transport
 * For all error cases, we assume that the address is bound
 * Returns 0 for success.
 *
 * fdl: My FD list
 * uaddr: the universal address
 */
static bool_t
check_bound(struct fdlist *fdl, char *uaddr)
{
        int fd;
        struct netbuf *na;
        struct t_bind taddr, *baddr;
        int ans;

        if (fdl->check_binding == FALSE)
                return (TRUE);

        na = uaddr2taddr(fdl->nconf, uaddr);
        if (!na)
                return (TRUE); /* punt, should never happen */

        taddr.addr = *na;
        taddr.qlen = 1;
        (void) mutex_lock(&fdl->fd_lock);
        fd = fdl->fd;
        baddr = (struct t_bind *)t_alloc(fd, T_BIND, T_ADDR);
        if (baddr == NULL) {
                (void) mutex_unlock(&fdl->fd_lock);
                netdir_free((char *)na, ND_ADDR);
                return (TRUE);
        }
        if (t_bind(fd, &taddr, baddr) != 0) {
                (void) mutex_unlock(&fdl->fd_lock);
                netdir_free((char *)na, ND_ADDR);
                (void) t_free((char *)baddr, T_BIND);
                return (TRUE);
        }
        if (t_unbind(fd) != 0) {
                /* Bad fd. Purge this fd */
                (void) t_close(fd);
                fdl->fd = t_open(fdl->nconf->nc_device, O_RDWR, NULL);
                if (fdl->fd == -1)
                        fdl->check_binding = FALSE;
        }
        (void) mutex_unlock(&fdl->fd_lock);
        ans = memcmp(taddr.addr.buf, baddr->addr.buf, baddr->addr.len);
        netdir_free((char *)na, ND_ADDR);
        (void) t_free((char *)baddr, T_BIND);
        return (ans == 0 ? FALSE : TRUE);
}

/*
 * Keep open one more file descriptor for this transport, which
 * will be used to determine whether the given service is up
 * or not by trying to bind to the registered address.
 * We are ignoring errors here. It trashes taddr and baddr;
 * but that perhaps should not matter.
 *
 * We check for the following conditions:
 *      1. Is it possible for t_bind to fail in the case where
 *              we bind to an already bound address and have any
 *              other error number besides TNOADDR.
 *      2. If an address is specified in bind addr, can I bind to
 *              the same address.
 *      3. If NULL is specified in bind addr, can I bind to the
 *              address to which the fd finally got bound.
 */
int
add_bndlist(struct netconfig *nconf, struct t_bind *taddr, struct t_bind *baddr)
{
        int fd;
        struct fdlist *fdl;
        struct netconfig *newnconf;
        struct t_info tinfo;
        struct t_bind tmpaddr;

        newnconf = getnetconfigent(nconf->nc_netid);
        if (newnconf == NULL)
                return (-1);
        fdl = (struct fdlist *)malloc((uint_t)sizeof (struct fdlist));
        if (fdl == NULL) {
                freenetconfigent(newnconf);
                syslog(LOG_ERR, "no memory!");
                return (-1);
        }
        (void) mutex_init(&fdl->fd_lock, USYNC_THREAD, NULL);
        fdl->nconf = newnconf;
        fdl->next = NULL;
        if (fdhead == NULL) {
                fdhead = fdl;
                fdtail = fdl;
        } else {
                fdtail->next = fdl;
                fdtail = fdl;
        }
        fdl->check_binding = FALSE;
        if ((fdl->fd = t_open(nconf->nc_device, O_RDWR, &tinfo)) < 0) {
                /*
                 * Note that we haven't dequeued this entry nor have we freed
                 * the netconfig structure.
                 */
                if (debugging) {
                        fprintf(stderr,
                            "%s: add_bndlist cannot open connection: %s",
                            nconf->nc_netid, t_errlist[t_errno]);
                }
                return (-1);
        }

        /* Set the qlen only for cots transports */
        switch (tinfo.servtype) {
        case T_COTS:
        case T_COTS_ORD:
                taddr->qlen = 1;
                break;
        case T_CLTS:
                taddr->qlen = 0;
                break;
        default:
                goto error;
        }

        if (t_bind(fdl->fd, taddr, baddr) != 0) {
                if (t_errno == TNOADDR) {
                        fdl->check_binding = TRUE;
                        return (0);     /* All is fine */
                }
                /* Perhaps condition #1 */
                if (debugging) {
                        fprintf(stderr, "%s: add_bndlist cannot bind (1): %s",
                            nconf->nc_netid, t_errlist[t_errno]);
                }
                goto not_bound;
        }

        /* Condition #2 */
        if (!memcmp(taddr->addr.buf, baddr->addr.buf,
            (int)baddr->addr.len)) {
                goto not_bound;
        }

        /* Condition #3 */
        t_unbind(fdl->fd);
        /* Set the qlen only for cots transports */
        switch (tinfo.servtype) {
        case T_COTS:
        case T_COTS_ORD:
                tmpaddr.qlen = 1;
                break;
        case T_CLTS:
                tmpaddr.qlen = 0;
                break;
        default:
                goto error;
        }
        tmpaddr.addr.len = tmpaddr.addr.maxlen = 0;
        tmpaddr.addr.buf = NULL;
        if (t_bind(fdl->fd, &tmpaddr, taddr) != 0) {
                if (debugging) {
                        fprintf(stderr, "%s: add_bndlist cannot bind (2): %s",
                            nconf->nc_netid, t_errlist[t_errno]);
                }
                goto error;
        }
        /* Now fdl->fd is bound to a transport chosen address */
        if ((fd = t_open(nconf->nc_device, O_RDWR, &tinfo)) < 0) {
                if (debugging) {
                        fprintf(stderr,
                            "%s: add_bndlist cannot open connection: %s",
                            nconf->nc_netid, t_errlist[t_errno]);
                }
                goto error;
        }
        if (t_bind(fd, taddr, baddr) != 0) {
                if (t_errno == TNOADDR) {
                        /*
                         * This transport is schizo.  Previously it handled a
                         * request to bind to an already bound transport by
                         * returning a different bind address, and now it's
                         * returning a TNOADDR for essentially the same
                         * request.  The spec may allow this behavior, so
                         * we'll just assume we can't do bind checking with
                         * this transport.
                         */
                        t_close(fd);
                        goto not_bound;
                }
                if (debugging) {
                        fprintf(stderr, "%s: add_bndlist cannot bind (3): %s",
                            nconf->nc_netid, t_errlist[t_errno]);
                }
                t_close(fd);
                goto error;
        }
        t_close(fd);
        if (!memcmp(taddr->addr.buf, baddr->addr.buf,
            (int)baddr->addr.len)) {
                switch (tinfo.servtype) {
                case T_COTS:
                case T_COTS_ORD:
                        if (baddr->qlen == 1) {
                                goto not_bound;
                        }
                        break;
                case T_CLTS:
                        goto not_bound;
                default:
                        goto error;
                }
        }

        t_unbind(fdl->fd);
        fdl->check_binding = TRUE;
        return (0);

not_bound:
        t_close(fdl->fd);
        fdl->fd = -1;
        return (1);

error:
        t_close(fdl->fd);
        fdl->fd = -1;
        return (-1);
}

bool_t
is_bound(char *netid, char *uaddr)
{
        struct fdlist *fdl;

        for (fdl = fdhead; fdl; fdl = fdl->next)
                if (strcmp(fdl->nconf->nc_netid, netid) == 0)
                        break;
        if (fdl == NULL)
                return (TRUE);
        return (check_bound(fdl, uaddr));
}

/* Return pointer to port string in the universal address */
#define UADDR_PRT_INDX(UADDR, PORT) { \
        PORT = strrchr(UADDR, '.'); \
        while (*--PORT != '.'); }
/*
 * Returns NULL if there was some system error.
 * Returns "" if the address was not bound, i.e the server crashed.
 * Returns the merged address otherwise.
 */
char *
mergeaddr(SVCXPRT *xprt, char *netid, char *uaddr, char *saddr)
{
        struct fdlist *fdl;
        struct nd_mergearg ma;
        int stat;

        for (fdl = fdhead; fdl; fdl = fdl->next)
                if (strcmp(fdl->nconf->nc_netid, netid) == 0)
                        break;
        if (fdl == NULL)
                return (NULL);
        if (check_bound(fdl, uaddr) == FALSE)
                /* that server died */
                return (nullstring);
        /*
         * If saddr is not NULL, the remote client may have included the
         * address by which it contacted us.  Use that for the "client" uaddr,
         * otherwise use the info from the SVCXPRT.
         */
        if (saddr != NULL) {
                ma.c_uaddr = saddr;
        } else {

                /* retrieve the client's address */
                ma.c_uaddr = taddr2uaddr(fdl->nconf, svc_getrpccaller(xprt));
                if (ma.c_uaddr == NULL) {
                        syslog(LOG_ERR, "taddr2uaddr failed for %s: %s",
                            fdl->nconf->nc_netid, netdir_sperror());
                        return (NULL);
                }

        }

        /* Not an INET address? */
        if ((strcmp(fdl->nconf->nc_protofmly, NC_INET) != 0) &&
            (strcmp(fdl->nconf->nc_protofmly, NC_INET6) != 0)) {
                ma.s_uaddr = uaddr;
                stat = netdir_options(fdl->nconf, ND_MERGEADDR, 0, (char *)&ma);
        }
        /* Inet address, but no xp_ltaddr */
        else if ((ma.s_uaddr = taddr2uaddr(fdl->nconf,
            &(xprt)->xp_ltaddr)) == NULL) {
                ma.s_uaddr = uaddr;
                stat = netdir_options(fdl->nconf, ND_MERGEADDR, 0, (char *)&ma);
        } else {
                /*
                 * (xprt)->xp_ltaddr contains portmap's port address.
                 * Overwrite this with actual application's port address
                 * before returning to the caller.
                 */
                char *s_uport, *uport;

                /* Get the INET/INET6 address part from ma.s_uaddr */
                UADDR_PRT_INDX(ma.s_uaddr, s_uport);
                *s_uport = '\0';

                /* Get the port info from uaddr */
                UADDR_PRT_INDX(uaddr, uport);

                ma.m_uaddr = malloc(strlen(ma.s_uaddr) + strlen(uport) + 1);
                if (ma.m_uaddr == NULL) {
                        syslog(LOG_ERR, "mergeaddr: no memory!");
                        free(ma.s_uaddr);
                        if (saddr == NULL)
                                free(ma.c_uaddr);
                        return (NULL);
                }

                /* Copy IP address into the Universal address holder */
                strcpy(ma.m_uaddr, ma.s_uaddr);
                /* Append port info to the Universal address holder */
                strcat(ma.m_uaddr, uport);
                free(ma.s_uaddr);
                stat = 0;
        }
        if (saddr == NULL) {
                free(ma.c_uaddr);
        }
        if (stat) {
                syslog(LOG_ERR, "netdir_merge failed for %s: %s",
                    fdl->nconf->nc_netid, netdir_sperror());
                return (NULL);
        }

        return (ma.m_uaddr);
}

/*
 * Returns a netconf structure from its internal list.  This
 * structure should not be freed.
 */
struct netconfig *
rpcbind_get_conf(char *netid)
{
        struct fdlist *fdl;

        for (fdl = fdhead; fdl; fdl = fdl->next)
                if (strcmp(fdl->nconf->nc_netid, netid) == 0)
                        break;
        if (fdl == NULL)
                return (NULL);
        return (fdl->nconf);
}