lib/dns/dlz.c

	dlz.c revision 03e200df5dc283f24a6a349f0b31d3eab26da893
/*
 * Copyright (C) 2002 Stichting NLnet, Netherlands, stichting@nlnet.nl.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the
 * above copyright notice and this permission notice appear in all
 * copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND STICHTING NLNET
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * STICHTING NLNET BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
 * USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * The development of Dynamically Loadable Zones (DLZ) for Bind 9 was
 * conceived and contributed by Rob Butler.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the
 * above copyright notice and this permission notice appear in all
 * copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ROB BUTLER
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * ROB BUTLER BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
 * USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * Copyright (C) 1999-2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: dlz.c,v 1.2 2005/09/05 00:11:01 marka Exp $ */

/*! \file */

/***
 *** Imports
 ***/

#include <config.h>

#include <dns/fixedname.h>
#include <dns/log.h>
#include <dns/master.h>
#include <dns/dlz.h>


#include <isc/buffer.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/once.h>
#include <isc/rwlock.h>
#include <isc/string.h>
#include <isc/util.h>

/***
 *** Supported DLZ DB Implementations Registry
 ***/

static ISC_LIST(dns_dlzimplementation_t) dlz_implementations;
static isc_rwlock_t dlz_implock;
static isc_once_t once = ISC_ONCE_INIT;

static void
dlz_initialize(void) {
    RUNTIME_CHECK(isc_rwlock_init(&dlz_implock, 0, 0) == ISC_R_SUCCESS);
    ISC_LIST_INIT(dlz_implementations);
}

/*%
 * Searches the dlz_implementations list for a driver matching name.
 */
static inline dns_dlzimplementation_t *
dlz_impfind(const char *name) {
    dns_dlzimplementation_t *imp;

    for (imp = ISC_LIST_HEAD(dlz_implementations);
         imp != NULL;
         imp = ISC_LIST_NEXT(imp, link))
        if (strcasecmp(name, imp->name) == 0)
            return (imp);
    return (NULL);
}

/***
 *** Basic DLZ Methods
 ***/

isc_result_t
dns_dlzallowzonexfr(dns_view_t *view, dns_name_t *name,
            isc_sockaddr_t *clientaddr, dns_db_t **dbp)
{
    isc_result_t result;
    dns_dlzallowzonexfr_t allowzonexfr;
    dns_dlzdb_t *dlzdatabase;

    /*
     * Performs checks to make sure data is as we expect it to be.
     */
    REQUIRE(DNS_DLZ_VALID(view->dlzdatabase));
    REQUIRE(name != NULL);
    REQUIRE(dbp != NULL && *dbp == NULL);

    /* ask driver if the zone is supported */
    dlzdatabase = view->dlzdatabase;
    allowzonexfr = dlzdatabase->implementation->methods->allowzonexfr;
    result = (*allowzonexfr)(dlzdatabase->implementation->driverarg,
                     dlzdatabase->dbdata, dlzdatabase->mctx,
                 view->rdclass, name, clientaddr, dbp);

    if (result == ISC_R_NOTIMPLEMENTED)
        return (ISC_R_NOTFOUND);
    return (result);
}

isc_result_t
dns_dlzcreate(isc_mem_t *mctx, const char *dlzname, const char *drivername,
          unsigned int argc, char *argv[], dns_dlzdb_t **dbp)
{
    dns_dlzimplementation_t *impinfo;
    isc_result_t result;

    /*
     * initialize the dlz_implementations list, this is guaranteed
     * to only really happen once.
     */
    RUNTIME_CHECK(isc_once_do(&once, dlz_initialize) == ISC_R_SUCCESS);

    /*
     * Performs checks to make sure data is as we expect it to be.
     */
    REQUIRE(dbp != NULL && *dbp == NULL);
    REQUIRE(dlzname != NULL);
    REQUIRE(drivername != NULL);
    REQUIRE(mctx != NULL);

    /* write log message */
    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
              DNS_LOGMODULE_DLZ, ISC_LOG_INFO,
              "Loading '%s' using driver %s", dlzname, drivername);

    /* lock the dlz_implementations list so we can search it. */
    RWLOCK(&dlz_implock, isc_rwlocktype_read);

    /* search for the driver implementation  */
    impinfo = dlz_impfind(drivername);
    if (impinfo == NULL) {
        RWUNLOCK(&dlz_implock, isc_rwlocktype_read);

        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "unsupported DLZ database driver '%s'."
                  "  %s not loaded.",
                  drivername, dlzname);

        return (ISC_R_NOTFOUND);
    }

    /* Allocate memory to hold the DLZ database driver */
    (*dbp) = isc_mem_get(mctx, sizeof(dns_dlzdb_t));
    if ((*dbp) == NULL) {
        RWUNLOCK(&dlz_implock, isc_rwlocktype_read);
        return (ISC_R_NOMEMORY);
    }

    /* Make sure memory region is set to all 0's */
    memset((*dbp), 0, sizeof(dns_dlzdb_t));

    (*dbp)->implementation = impinfo;

    /* Create a new database using implementation 'drivername'. */
    result = ((impinfo->methods->create)(mctx, dlzname, argc, argv,
                         impinfo->driverarg,
                         &(*dbp)->dbdata));

    /* mark the DLZ driver as valid */
    if (result == ISC_R_SUCCESS) {
        RWUNLOCK(&dlz_implock, isc_rwlocktype_read);
        (*dbp)->magic = DNS_DLZ_MAGIC;
        isc_mem_attach(mctx, &(*dbp)->mctx);
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
                  "DLZ driver loaded successfully.");
        return (ISC_R_SUCCESS);
    } else {
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_ERROR,
                  "DLZ driver failed to load.");
    }

    /* impinfo->methods->create failed. */
    RWUNLOCK(&dlz_implock, isc_rwlocktype_read);
    isc_mem_put(mctx, (*dbp), sizeof(dns_dlzdb_t));
    return (result);
}

void
dns_dlzdestroy(dns_dlzdb_t **dbp) {
    isc_mem_t *mctx;
    dns_dlzdestroy_t destroy;

    /* Write debugging message to log */
    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
              DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
              "Unloading DLZ driver.");

    /*
     * Perform checks to make sure data is as we expect it to be.
     */
    REQUIRE(dbp != NULL && DNS_DLZ_VALID(*dbp));

    /* call the drivers destroy method */
    if ((*dbp) != NULL) {
        mctx = (*dbp)->mctx;
        destroy = (*dbp)->implementation->methods->destroy;
        (*destroy)((*dbp)->implementation->driverarg,(*dbp)->dbdata);
        /* return memory */
        isc_mem_put(mctx, (*dbp), sizeof(dns_dlzdb_t));
        isc_mem_detach(&mctx);
    }

    *dbp = NULL;
}


isc_result_t
dns_dlzfindzone(dns_view_t *view, dns_name_t *name, unsigned int minlabels,
        dns_db_t **dbp)
{
    dns_fixedname_t fname;
    dns_name_t *zonename;
    unsigned int namelabels;
    unsigned int i;
    isc_result_t result;
    dns_dlzfindzone_t findzone;
    dns_dlzdb_t *dlzdatabase;

    /*
     * Performs checks to make sure data is as we expect it to be.
     */
    REQUIRE(DNS_DLZ_VALID(view->dlzdatabase));
    REQUIRE(name != NULL);
    REQUIRE(dbp != NULL && *dbp == NULL);

    /* setup a "fixed" dns name */
    dns_fixedname_init(&fname);
    zonename = dns_fixedname_name(&fname);

    /* count the number of labels in the name */
    namelabels = dns_name_countlabels(name);

    /*
     * loop through starting with the longest domain name and
     * trying shorter names portions of the name until we find a
     * match, have an error, or are below the 'minlabels'
     * threshold.  minlabels is 0, if the standard database didn't
     * have a zone name match.  Otherwise minlables is the number
     * of labels in that name.  We need to beat that for a
     * "better" match for the DLZ database to be authoritative
     * instead of the standard database.
     */
    for (i = namelabels; i > minlabels && i > 1; i--) {
        if (i == namelabels) {
            result = dns_name_copy(name, zonename, NULL);
            if (result != ISC_R_SUCCESS)
                return (result);
        } else
            dns_name_split(name, i, NULL, zonename);

        /* ask SDLZ driver if the zone is supported */
        dlzdatabase = view->dlzdatabase;
        findzone = dlzdatabase->implementation->methods->findzone;
        result = (*findzone)(dlzdatabase->implementation->driverarg,
                     dlzdatabase->dbdata, dlzdatabase->mctx,
                     view->rdclass, zonename, dbp);
        if (result != ISC_R_NOTFOUND)
            return (result);
    }
    return (ISC_R_NOTFOUND);
}

/*%
 * Registers a DLZ driver.  This basically just adds the dlz
 * driver to the list of available drivers in the dlz_implementations list.
 */
isc_result_t
dns_dlzregister(const char *drivername, const dns_dlzmethods_t *methods,
        void *driverarg, isc_mem_t *mctx,
        dns_dlzimplementation_t **dlzimp)
{

    dns_dlzimplementation_t *dlz_imp;

    /* Write debugging message to log */
    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
              DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
              "Registering DLZ driver '%s'", drivername);

    /*
     * Performs checks to make sure data is as we expect it to be.
     */
    REQUIRE(drivername != NULL);
    REQUIRE(methods != NULL);
    REQUIRE(methods->create != NULL);
    REQUIRE(methods->destroy != NULL);
    REQUIRE(methods->findzone != NULL);
    REQUIRE(mctx != NULL);
    REQUIRE(dlzimp != NULL && *dlzimp == NULL);

    /*
     * initialize the dlz_implementations list, this is guaranteed
     * to only really happen once.
     */
    RUNTIME_CHECK(isc_once_do(&once, dlz_initialize) == ISC_R_SUCCESS);

    /* lock the dlz_implementations list so we can modify it. */
    RWLOCK(&dlz_implock, isc_rwlocktype_write);

    /*
     * check that another already registered driver isn't using
     * the same name
     */
    dlz_imp = dlz_impfind(drivername);
    if (dlz_imp != NULL) {
        isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
                  DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
                  "DLZ Driver '%s' already registered",
                  drivername);
        RWUNLOCK(&dlz_implock, isc_rwlocktype_write);
        return (ISC_R_EXISTS);
    }

    /*
     * Allocate memory for a dlz_implementation object.  Error if
     * we cannot.
     */
    dlz_imp = isc_mem_get(mctx, sizeof(dns_dlzimplementation_t));
    if (dlz_imp == NULL) {
        RWUNLOCK(&dlz_implock, isc_rwlocktype_write);
        return (ISC_R_NOMEMORY);
    }

    /* Make sure memory region is set to all 0's */
    memset(dlz_imp, 0, sizeof(dns_dlzimplementation_t));

    /* Store the data passed into this method */
    dlz_imp->name = drivername;
    dlz_imp->methods = methods;
    dlz_imp->mctx = NULL;
    dlz_imp->driverarg = driverarg;

    /* attach the new dlz_implementation object to a memory context */
    isc_mem_attach(mctx, &dlz_imp->mctx);

    /*
     * prepare the dlz_implementation object to be put in a list,
     * and append it to the list
     */
    ISC_LINK_INIT(dlz_imp, link);
    ISC_LIST_APPEND(dlz_implementations, dlz_imp, link);

    /* Unlock the dlz_implementations list.  */
    RWUNLOCK(&dlz_implock, isc_rwlocktype_write);

    /* Pass back the dlz_implementation that we created. */
    *dlzimp = dlz_imp;

    return (ISC_R_SUCCESS);
}

/*%
 * Helper function for dns_dlzstrtoargv().
 * Pardon the gratuitous recursion.
 */
static isc_result_t
dns_dlzstrtoargvsub(isc_mem_t *mctx, char *s, unsigned int *argcp,
            char ***argvp, unsigned int n)
{
    isc_result_t result;

 restart:
    /* Discard leading whitespace. */
    while (*s == ' ' || *s == '\t')
        s++;

    if (*s == '\0') {
        /* We have reached the end of the string. */
        *argcp = n;
        *argvp = isc_mem_get(mctx, n * sizeof(char *));
        if (*argvp == NULL)
            return (ISC_R_NOMEMORY);
    } else {
        char *p = s;
        while (*p != ' ' && *p != '\t' && *p != '\0' && *p != '{') {
            if (*p == '\n') {
                *p = ' ';
                goto restart;
            }
            p++;
        }

        /* do "grouping", items between { and } are one arg */
        if (*p == '{') {
            char *t = p;
            /*
             * shift all characters to left by 1 to get rid of '{'
             */
            while (*t != '\0') {
                t++;
                *(t-1) = *t;
            }
            while (*p != '\0' && *p != '}') {
                p++;
            }
            /* get rid of '}' character */
            if (*p == '}') {
                *p = '\0';
                p++;
            }
            /* normal case, no "grouping" */
        } else if (*p != '\0')
            *p++ = '\0';

        result = dns_dlzstrtoargvsub(mctx, p, argcp, argvp, n + 1);
        if (result != ISC_R_SUCCESS)
            return (result);
        (*argvp)[n] = s;
    }
    return (ISC_R_SUCCESS);
}

/*%
 * Tokenize the string "s" into whitespace-separated words,
 * return the number of words in '*argcp' and an array
 * of pointers to the words in '*argvp'.  The caller
 * must free the array using isc_mem_put().  The string
 * is modified in-place.
 */
isc_result_t
dns_dlzstrtoargv(isc_mem_t *mctx, char *s,
         unsigned int *argcp, char ***argvp)
{
    return(dns_dlzstrtoargvsub(mctx, s, argcp, argvp, 0));
}

/*%
 * Unregisters a DLZ driver.  This basically just removes the dlz
 * driver from the list of available drivers in the dlz_implementations list.
 */
void
dns_dlzunregister(dns_dlzimplementation_t **dlzimp) {
    dns_dlzimplementation_t *dlz_imp;
    isc_mem_t *mctx;

    /* Write debugging message to log */
    isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE,
              DNS_LOGMODULE_DLZ, ISC_LOG_DEBUG(2),
              "Unregistering DLZ driver.");

    /*
     * Performs checks to make sure data is as we expect it to be.
     */
    REQUIRE(dlzimp != NULL && *dlzimp != NULL);

    /*
     * initialize the dlz_implementations list, this is guaranteed
     * to only really happen once.
     */
    RUNTIME_CHECK(isc_once_do(&once, dlz_initialize) == ISC_R_SUCCESS);

    dlz_imp = *dlzimp;

    /* lock the dlz_implementations list so we can modify it. */
    RWLOCK(&dlz_implock, isc_rwlocktype_write);

    /* remove the dlz_implementation object from the list */
    ISC_LIST_UNLINK(dlz_implementations, dlz_imp, link);
    mctx = dlz_imp->mctx;

    /*
     * return the memory back to the available memory pool and
     * remove it from the memory context.
     */
    isc_mem_put(mctx, dlz_imp, sizeof(dns_dlzimplementation_t));
    isc_mem_detach(&mctx);

    /* Unlock the dlz_implementations list. */
    RWUNLOCK(&dlz_implock, isc_rwlocktype_write);
}