sdlz.c

非常好的dns解析软件

/*
 * Portions Copyright (C) 2005-2007  Internet Systems Consortium, Inc. ("ISC")
 * Portions 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 ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC 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) 2002 Stichting NLnet, Netherlands, [e-mail].
 *
 * 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.
 */

/* $Id: sdlz.c,v 1.2.2.9 2007/02/14 23:45:43 marka Exp $ */

/*! \file */

#include <config.h>
#include <string.h>

#include <isc/buffer.h>
#include <isc/lex.h>
#include <isc/log.h>
#include <isc/rwlock.h>
#include <isc/string.h>
#include <isc/util.h>
#include <isc/magic.h>
#include <isc/mem.h>
#include <isc/once.h>
#include <isc/print.h>
#include <isc/region.h>

#include <dns/callbacks.h>
#include <dns/db.h>
#include <dns/dbiterator.h>
#include <dns/dlz.h>
#include <dns/fixedname.h>
#include <dns/log.h>
#include <dns/rdata.h>
#include <dns/rdatalist.h>
#include <dns/rdataset.h>
#include <dns/rdatasetiter.h>
#include <dns/rdatatype.h>
#include <dns/result.h>
#include <dns/master.h>
#include <dns/sdlz.h>
#include <dns/types.h>

#include "rdatalist_p.h"

/*
 * Private Types
 */

struct dns_sdlzimplementation {
	const dns_sdlzmethods_t		*methods;
	isc_mem_t			*mctx;
	void				*driverarg;
	unsigned int			flags;
	isc_mutex_t			driverlock;
	dns_dlzimplementation_t		*dlz_imp;
};

struct dns_sdlz_db {
	/* Unlocked */
	dns_db_t			common;
	void				*dbdata;
	dns_sdlzimplementation_t	*dlzimp;
	isc_mutex_t			refcnt_lock;
	/* Locked */
	unsigned int			references;
};

struct dns_sdlzlookup {
	/* Unlocked */
	unsigned int			magic;
	dns_sdlz_db_t			*sdlz;
	ISC_LIST(dns_rdatalist_t)	lists;
	ISC_LIST(isc_buffer_t)		buffers;
	dns_name_t			*name;
	ISC_LINK(dns_sdlzlookup_t)	link;
	isc_mutex_t			lock;
	dns_rdatacallbacks_t		callbacks;
	/* Locked */
	unsigned int			references;
};

typedef struct dns_sdlzlookup dns_sdlznode_t;

struct dns_sdlzallnodes {
	dns_dbiterator_t		common;
	ISC_LIST(dns_sdlznode_t)	nodelist;
	dns_sdlznode_t			*current;
	dns_sdlznode_t			*origin;
};

typedef dns_sdlzallnodes_t sdlz_dbiterator_t;

typedef struct sdlz_rdatasetiter {
	dns_rdatasetiter_t		common;
	dns_rdatalist_t			*current;
} sdlz_rdatasetiter_t;


#define SDLZDB_MAGIC		ISC_MAGIC('D', 'L', 'Z', 'S')

/*
 * Note that "impmagic" is not the first four bytes of the struct, so
 * ISC_MAGIC_VALID cannot be used.
 */

#define VALID_SDLZDB(sdlzdb)	((sdlzdb) != NULL && \
				 (sdlzdb)->common.impmagic == SDLZDB_MAGIC)

#define SDLZLOOKUP_MAGIC	ISC_MAGIC('D','L','Z','L')
#define VALID_SDLZLOOKUP(sdlzl)	ISC_MAGIC_VALID(sdlzl, SDLZLOOKUP_MAGIC)
#define VALID_SDLZNODE(sdlzn)	VALID_SDLZLOOKUP(sdlzn)

/* These values are taken from RFC 1537 */
#define SDLZ_DEFAULT_REFRESH	(60 * 60 * 8)
#define SDLZ_DEFAULT_RETRY	(60 * 60 * 2)
#define SDLZ_DEFAULT_EXPIRE	(60 * 60 * 24 * 7)
#define SDLZ_DEFAULT_MINIMUM	(60 * 60 * 24)

/* This is a reasonable value */
#define SDLZ_DEFAULT_TTL	(60 * 60 * 24)

static int dummy;

#define MAYBE_LOCK(imp) \
	do { \
		unsigned int flags = imp->flags; \
		if ((flags & DNS_SDLZFLAG_THREADSAFE) == 0) \
			LOCK(&imp->driverlock); \
	} while (0)

#define MAYBE_UNLOCK(imp) \
	do { \
		unsigned int flags = imp->flags; \
		if ((flags & DNS_SDLZFLAG_THREADSAFE) == 0) \
			UNLOCK(&imp->driverlock); \
	} while (0)

/*
 * Forward references.  Try to keep these to a minimum.
 */

static void list_tordataset(dns_rdatalist_t *rdatalist,
			    dns_db_t *db, dns_dbnode_t *node,
			    dns_rdataset_t *rdataset);

static void detachnode(dns_db_t *db, dns_dbnode_t **targetp);

static void		dbiterator_destroy(dns_dbiterator_t **iteratorp);
static isc_result_t	dbiterator_first(dns_dbiterator_t *iterator);
static isc_result_t	dbiterator_last(dns_dbiterator_t *iterator);
static isc_result_t	dbiterator_seek(dns_dbiterator_t *iterator,
					dns_name_t *name);
static isc_result_t	dbiterator_prev(dns_dbiterator_t *iterator);
static isc_result_t	dbiterator_next(dns_dbiterator_t *iterator);
static isc_result_t	dbiterator_current(dns_dbiterator_t *iterator,
					   dns_dbnode_t **nodep,
					   dns_name_t *name);
static isc_result_t	dbiterator_pause(dns_dbiterator_t *iterator);
static isc_result_t	dbiterator_origin(dns_dbiterator_t *iterator,
					  dns_name_t *name);

static dns_dbiteratormethods_t dbiterator_methods = {
	dbiterator_destroy,
	dbiterator_first,
	dbiterator_last,
	dbiterator_seek,
	dbiterator_prev,
	dbiterator_next,
	dbiterator_current,
	dbiterator_pause,
	dbiterator_origin
};

/*
 * Utility functions
 */

/*% Converts the input string to lowercase, in place. */

static void
dns_sdlz_tolower(char *str) {

	unsigned int len = strlen(str);
	unsigned int i;

	for (i = 0; i < len; i++) {
		if (str[i] >= 'A' && str[i] <= 'Z')
			str[i] += 32;
	}

}

static inline unsigned int
initial_size(const char *data) {
	unsigned int len = (strlen(data) / 64) + 1;
	return (len * 64 + 64);
}

/*
 * Rdataset Iterator Methods. These methods were "borrowed" from the SDB
 * driver interface.  See the SDB driver interface documentation for more info.
 */

static void
rdatasetiter_destroy(dns_rdatasetiter_t **iteratorp) {
	sdlz_rdatasetiter_t *sdlziterator =
		(sdlz_rdatasetiter_t *)(*iteratorp);

	detachnode(sdlziterator->common.db, &sdlziterator->common.node);
	isc_mem_put(sdlziterator->common.db->mctx, sdlziterator,
		    sizeof(sdlz_rdatasetiter_t));
	*iteratorp = NULL;
}

static isc_result_t
rdatasetiter_first(dns_rdatasetiter_t *iterator) {
	sdlz_rdatasetiter_t *sdlziterator = (sdlz_rdatasetiter_t *)iterator;
	dns_sdlznode_t *sdlznode = (dns_sdlznode_t *)iterator->node;

	if (ISC_LIST_EMPTY(sdlznode->lists))
		return (ISC_R_NOMORE);
	sdlziterator->current = ISC_LIST_HEAD(sdlznode->lists);
	return (ISC_R_SUCCESS);
}

static isc_result_t
rdatasetiter_next(dns_rdatasetiter_t *iterator) {
	sdlz_rdatasetiter_t *sdlziterator = (sdlz_rdatasetiter_t *)iterator;

	sdlziterator->current = ISC_LIST_NEXT(sdlziterator->current, link);
	if (sdlziterator->current == NULL)
		return (ISC_R_NOMORE);
	else
		return (ISC_R_SUCCESS);
}

static void
rdatasetiter_current(dns_rdatasetiter_t *iterator, dns_rdataset_t *rdataset) {
	sdlz_rdatasetiter_t *sdlziterator = (sdlz_rdatasetiter_t *)iterator;

	list_tordataset(sdlziterator->current, iterator->db, iterator->node,
			rdataset);
}

static dns_rdatasetitermethods_t rdatasetiter_methods = {
	rdatasetiter_destroy,
	rdatasetiter_first,
	rdatasetiter_next,
	rdatasetiter_current
};

/*
 * DB routines. These methods were "borrowed" from the SDB driver interface.
 * See the SDB driver interface documentation for more info.
 */

static void
attach(dns_db_t *source, dns_db_t **targetp) {
	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *) source;

	REQUIRE(VALID_SDLZDB(sdlz));

	LOCK(&sdlz->refcnt_lock);
	REQUIRE(sdlz->references > 0);
	sdlz->references++;
	UNLOCK(&sdlz->refcnt_lock);

	*targetp = source;
}

static void
destroy(dns_sdlz_db_t *sdlz) {
	isc_mem_t *mctx;
	mctx = sdlz->common.mctx;

	sdlz->common.magic = 0;
	sdlz->common.impmagic = 0;

	isc_mutex_destroy(&sdlz->refcnt_lock);

	dns_name_free(&sdlz->common.origin, mctx);

	isc_mem_put(mctx, sdlz, sizeof(dns_sdlz_db_t));
	isc_mem_detach(&mctx);
}

static void
detach(dns_db_t **dbp) {
	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *)(*dbp);
	isc_boolean_t need_destroy = ISC_FALSE;

	REQUIRE(VALID_SDLZDB(sdlz));
	LOCK(&sdlz->refcnt_lock);
	REQUIRE(sdlz->references > 0);
	sdlz->references--;
	if (sdlz->references == 0)
		need_destroy = ISC_TRUE;
	UNLOCK(&sdlz->refcnt_lock);

	if (need_destroy)
		destroy(sdlz);

	*dbp = NULL;
}

static isc_result_t
beginload(dns_db_t *db, dns_addrdatasetfunc_t *addp, dns_dbload_t **dbloadp) {
	UNUSED(db);
	UNUSED(addp);
	UNUSED(dbloadp);
	return (ISC_R_NOTIMPLEMENTED);
}

static isc_result_t
endload(dns_db_t *db, dns_dbload_t **dbloadp) {
	UNUSED(db);
	UNUSED(dbloadp);
	return (ISC_R_NOTIMPLEMENTED);
}

static isc_result_t
dump(dns_db_t *db, dns_dbversion_t *version, const char *filename,
     dns_masterformat_t masterformat)
{
	UNUSED(db);
	UNUSED(version);
	UNUSED(filename);
	UNUSED(masterformat);
	return (ISC_R_NOTIMPLEMENTED);
}

static void
currentversion(dns_db_t *db, dns_dbversion_t **versionp) {
	REQUIRE(versionp != NULL && *versionp == NULL);

	UNUSED(db);

	*versionp = (void *) &dummy;
	return;
}

static isc_result_t
newversion(dns_db_t *db, dns_dbversion_t **versionp) {
	UNUSED(db);
	UNUSED(versionp);

	return (ISC_R_NOTIMPLEMENTED);
}

static void
attachversion(dns_db_t *db, dns_dbversion_t *source,
	      dns_dbversion_t **targetp)
{
	REQUIRE(source != NULL && source == (void *) &dummy);

	UNUSED(db);
	UNUSED(source);
	UNUSED(targetp);
	*targetp = source;
}

static void
closeversion(dns_db_t *db, dns_dbversion_t **versionp, isc_boolean_t commit) {
	REQUIRE(versionp != NULL && *versionp == (void *) &dummy);
	REQUIRE(commit == ISC_FALSE);

	UNUSED(db);
	UNUSED(commit);

	*versionp = NULL;
}

static isc_result_t
createnode(dns_sdlz_db_t *sdlz, dns_sdlznode_t **nodep) {
	dns_sdlznode_t *node;
	isc_result_t result;

	node = isc_mem_get(sdlz->common.mctx, sizeof(dns_sdlznode_t));
	if (node == NULL)
		return (ISC_R_NOMEMORY);

	node->sdlz = NULL;
	attach((dns_db_t *)sdlz, (dns_db_t **)&node->sdlz);
	ISC_LIST_INIT(node->lists);
	ISC_LIST_INIT(node->buffers);
	ISC_LINK_INIT(node, link);
	node->name = NULL;
	result = isc_mutex_init(&node->lock);
	if (result != ISC_R_SUCCESS) {
		UNEXPECTED_ERROR(__FILE__, __LINE__,
				 "isc_mutex_init() failed: %s",
				 isc_result_totext(result));
		isc_mem_put(sdlz->common.mctx, node, sizeof(dns_sdlznode_t));
		return (ISC_R_UNEXPECTED);
	}
	dns_rdatacallbacks_init(&node->callbacks);
	node->references = 1;
	node->magic = SDLZLOOKUP_MAGIC;

	*nodep = node;
	return (ISC_R_SUCCESS);
}

static void
destroynode(dns_sdlznode_t *node) {
	dns_rdatalist_t *list;
	dns_rdata_t *rdata;
	isc_buffer_t *b;
	dns_sdlz_db_t *sdlz;
	dns_db_t *db;
	isc_mem_t *mctx;

	sdlz = node->sdlz;
	mctx = sdlz->common.mctx;

	while (!ISC_LIST_EMPTY(node->lists)) {
		list = ISC_LIST_HEAD(node->lists);
		while (!ISC_LIST_EMPTY(list->rdata)) {
			rdata = ISC_LIST_HEAD(list->rdata);
			ISC_LIST_UNLINK(list->rdata, rdata, link);
			isc_mem_put(mctx, rdata, sizeof(dns_rdata_t));
		}
		ISC_LIST_UNLINK(node->lists, list, link);
		isc_mem_put(mctx, list, sizeof(dns_rdatalist_t));
	}

	while (!ISC_LIST_EMPTY(node->buffers)) {
		b = ISC_LIST_HEAD(node->buffers);
		ISC_LIST_UNLINK(node->buffers, b, link);
		isc_buffer_free(&b);
	}

	if (node->name != NULL) {
		dns_name_free(node->name, mctx);
		isc_mem_put(mctx, node->name, sizeof(dns_name_t));
	}
	DESTROYLOCK(&node->lock);
	node->magic = 0;
	isc_mem_put(mctx, node, sizeof(dns_sdlznode_t));
	db = &sdlz->common;
	detach(&db);
}

static isc_result_t
findnode(dns_db_t *db, dns_name_t *name, isc_boolean_t create,
	 dns_dbnode_t **nodep)
{
	dns_sdlz_db_t *sdlz = (dns_sdlz_db_t *)db;
	dns_sdlznode_t *node = NULL;
	isc_result_t result;
	isc_buffer_t b;
	char namestr[DNS_NAME_MAXTEXT + 1];
	isc_buffer_t b2;
	char zonestr[DNS_NAME_MAXTEXT + 1];
	isc_boolean_t isorigin;
	dns_sdlzauthorityfunc_t authority;

	REQUIRE(VALID_SDLZDB(sdlz));
	REQUIRE(create == ISC_FALSE);
	REQUIRE(nodep != NULL && *nodep == NULL);

	UNUSED(name);
	UNUSED(create);

	isc_buffer_init(&b, namestr, sizeof(namestr));
	if ((sdlz->dlzimp->flags & DNS_SDLZFLAG_RELATIVEOWNER) != 0) {
		dns_name_t relname;
		unsigned int labels;

		labels = dns_name_countlabels(name) -
			 dns_name_countlabels(&db->origin);
		dns_name_init(&relname, NULL);
		dns_name_getlabelsequence(name, 0, labels, &relname);
		result = dns_name_totext(&relname, ISC_TRUE, &b);
		if (result != ISC_R_SUCCESS)
			return (result);
	} else {
		result = dns_name_totext(name, ISC_TRUE, &b);
		if (result != ISC_R_SUCCESS)
			return (result);
	}
	isc_buffer_putuint8(&b, 0);

	isc_buffer_init(&b2, zonestr, sizeof(zonestr));
	result = dns_name_totext(&sdlz->common.origin, ISC_TRUE, &b2);
	if (result != ISC_R_SUCCESS)
		return (result);
	isc_buffer_putuint8(&b2, 0);

	result = createnode(sdlz, &node);
	if (result != ISC_R_SUCCESS)
		return (result);

	isorigin = dns_name_equal(name, &sdlz->common.origin);

	/* make sure strings are always lowercase */
	dns_sdlz_tolower(zonestr);
	dns_sdlz_tolower(namestr);

	MAYBE_LOCK(sdlz->dlzimp);

	/* try to lookup the host (namestr) */
	result = sdlz->dlzimp->methods->lookup(zonestr, namestr,
					       sdlz->dlzimp->driverarg,
					       sdlz->dbdata, node);

	/*
	 * if the host (namestr) was not found, try to lookup a
	 * "wildcard" host.
	 */
	if (result != ISC_R_SUCCESS) {
		result = sdlz->dlzimp->methods->lookup(zonestr, "*",
						       sdlz->dlzimp->driverarg,
						       sdlz->dbdata, node);
	}

	MAYBE_UNLOCK(sdlz->dlzimp);

	if (result != ISC_R_SUCCESS && !isorigin) {
		destroynode(node);
		return (result);
	}

	if (isorigin && sdlz->dlzimp->methods->authority != NULL) {
		MAYBE_LOCK(sdlz->dlzimp);
		authority = sdlz->dlzimp->methods->authority;
		result = (*authority)(zonestr, sdlz->dlzimp->driverarg,
				      sdlz->dbdata, node);
		MAYBE_UNLOCK(sdlz->dlzimp);
		if (result != ISC_R_SUCCESS &&
		    result != ISC_R_NOTIMPLEMENTED) {
			destroynode(node);
			return (result);
		}
	}

	*nodep = node;
	return (ISC_R_SUCCESS);
}

static isc_result_t
findzonecut(dns_db_t *db, dns_name_t *name, unsigned int options,
	    isc_stdtime_t now, dns_dbnode_t **nodep, dns_name_t *foundname,
	    dns_rdataset_t *rdataset, dns_rdataset_t *sigrdataset)
{
	UNUSED(db);
	UNUSED(name);
	UNUSED(options);
	UNUSED(now);