/*
 * Copyright (C) 2011  Internet Systems Consortium, Inc. ("ISC")
 *
 * 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 THE AUTHOR
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * THE AUTHOR 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.
 */

/*
 * This header provides a minimal set of defines and typedefs needed
 * for building an external DLZ module for bind9. When creating a new
 * external DLZ driver, please copy this header into your own source
 * tree.
 */

#ifndef DLZ_MINIMAL_H
#define DLZ_MINIMAL_H 1

#include <inttypes.h>
#include <stdbool.h>
#include <sys/types.h>
#include <sys/socket.h>
#ifdef ISC_PLATFORM_HAVESYSUNH
#include <sys/un.h>
#endif
#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>

typedef unsigned int isc_result_t;
typedef uint32_t dns_ttl_t;

/*
 * Define DLZ_DLOPEN_VERSION to different values to use older versions
 * of the interface
 */
#ifndef DLZ_DLOPEN_VERSION
#define DLZ_DLOPEN_VERSION 3
#define DLZ_DLOPEN_AGE 0
#endif

/* return these in flags from dlz_version() */
#define DNS_SDLZFLAG_THREADSAFE		0x00000001U
#define DNS_SDLZFLAG_RELATIVEOWNER	0x00000002U
#define DNS_SDLZFLAG_RELATIVERDATA	0x00000004U

/* result codes */
#define ISC_R_SUCCESS			0
#define ISC_R_NOMEMORY			1
#define ISC_R_NOPERM			6
#define ISC_R_NOSPACE			19
#define ISC_R_NOTFOUND			23
#define ISC_R_FAILURE			25
#define ISC_R_NOTIMPLEMENTED		27
#define ISC_R_NOMORE			29
#define ISC_R_INVALIDFILE		30
#define ISC_R_UNEXPECTED		34
#define ISC_R_FILENOTFOUND		38

/* log levels */
#define ISC_LOG_INFO		(-1)
#define ISC_LOG_NOTICE		(-2)
#define ISC_LOG_WARNING 	(-3)
#define ISC_LOG_ERROR		(-4)
#define ISC_LOG_CRITICAL	(-5)
#define ISC_LOG_DEBUG(level)	(level)

/* other useful definitions */
#define UNUSED(x) (void)(x)
#define DE_CONST(konst, var) \
	do { \
		union { const void *k; void *v; } _u; \
		_u.k = konst; \
		var = _u.v; \
	} while (0)

/* opaque structures */
typedef void *dns_sdlzlookup_t;
typedef void *dns_sdlzallnodes_t;
typedef void *dns_view_t;
typedef void *dns_dlzdb_t;

#if DLZ_DLOPEN_VERSION > 1
/*
 * Method and type definitions needed for retrieval of client info
 * from the caller.
 */
typedef struct isc_sockaddr {
	union {
		struct sockaddr         sa;
		struct sockaddr_in      sin;
		struct sockaddr_in6     sin6;
#ifdef ISC_PLATFORM_HAVESYSUNH
		struct sockaddr_un      sunix;
#endif
	}                               type;
	unsigned int                    length;
	void *                          link;
} isc_sockaddr_t;

#define DNS_CLIENTINFO_VERSION 2
typedef struct dns_clientinfo {
	uint16_t version;
	void *data;
	void *dbversion;
} dns_clientinfo_t;

typedef isc_result_t (*dns_clientinfo_sourceip_t)(dns_clientinfo_t *client,
						  isc_sockaddr_t **addrp);

typedef isc_result_t (*dns_clientinfo_version_t)(dns_clientinfo_t *client,
						  void **addrp);

#define DNS_CLIENTINFOMETHODS_VERSION 2
#define DNS_CLIENTINFOMETHODS_AGE 1
typedef struct dns_clientinfomethods {
	uint16_t version;
	uint16_t age;
	dns_clientinfo_sourceip_t sourceip;
	dns_clientinfo_version_t dbversion;
} dns_clientinfomethods_t;
#endif /* DLZ_DLOPEN_VERSION > 1 */

/*
 * Method definitions for callbacks provided by the dlopen driver
 */
typedef void log_t(int level, const char *fmt, ...);

typedef isc_result_t dns_sdlz_putrr_t(dns_sdlzlookup_t *lookup,
				      const char *type,
				      dns_ttl_t ttl,
				      const char *data);

typedef isc_result_t dns_sdlz_putnamedrr_t(dns_sdlzallnodes_t *allnodes,
					   const char *name,
					   const char *type,
					   dns_ttl_t ttl,
					   const char *data);

#if DLZ_DLOPEN_VERSION < 3
typedef isc_result_t dns_dlz_writeablezone_t(dns_view_t *view,
					     const char *zone_name);
#else /* DLZ_DLOPEN_VERSION >= 3 */
typedef isc_result_t dns_dlz_writeablezone_t(dns_view_t *view,
					     dns_dlzdb_t *dlzdb,
					     const char *zone_name);
#endif /* DLZ_DLOPEN_VERSION */

/*
 * prototypes for the functions you can include in your module
 */

/*
 * dlz_version() is required for all DLZ external drivers. It should
 * return DLZ_DLOPEN_VERSION.  'flags' is updated to indicate capabilities
 * of the module.  In particular, if the module is thread-safe then it
 * sets 'flags' to include DNS_SDLZFLAG_THREADSAFE.  Other capability
 * flags may be added in the future.
 */
int
dlz_version(unsigned int *flags);

/*
 * dlz_create() is required for all DLZ external drivers.
 */
isc_result_t
dlz_create(const char *dlzname, unsigned int argc, char *argv[],
	   void **dbdata, ...);

/*
 * dlz_destroy() is optional, and will be called when the driver is
 * unloaded if supplied
 */
void
dlz_destroy(void *dbdata);

/*
 * dlz_findzonedb is required for all DLZ external drivers
 */
#if DLZ_DLOPEN_VERSION < 3
isc_result_t
dlz_findzonedb(void *dbdata, const char *name);
#else /* DLZ_DLOPEN_VERSION >= 3 */
isc_result_t
dlz_findzonedb(void *dbdata, const char *name,
	       dns_clientinfomethods_t *methods,
	       dns_clientinfo_t *clientinfo);
#endif /* DLZ_DLOPEN_VERSION */

/*
 * dlz_lookup is required for all DLZ external drivers
 */
#if DLZ_DLOPEN_VERSION == 1
isc_result_t
dlz_lookup(const char *zone, const char *name, void *dbdata,
	   dns_sdlzlookup_t *lookup);
#else /* DLZ_DLOPEN_VERSION > 1 */
isc_result_t
dlz_lookup(const char *zone, const char *name, void *dbdata,
	   dns_sdlzlookup_t *lookup,
	   dns_clientinfomethods_t *methods,
	   dns_clientinfo_t *clientinfo);
#endif /* DLZ_DLOPEN_VERSION */

/*
 * dlz_authority() is optional if dlz_lookup() supplies
 * authority information (i.e., SOA, NS) for the dns record
 */
isc_result_t
dlz_authority(const char *zone, void *dbdata, dns_sdlzlookup_t *lookup);

/*
 * dlz_allowzonexfr() is optional, and should be supplied if you want to
 * support zone transfers
 */
isc_result_t
dlz_allowzonexfr(void *dbdata, const char *name, const char *client);

/*
 * dlz_allnodes() is optional, but must be supplied if supply a
 * dlz_allowzonexfr() function
 */
isc_result_t
dlz_allnodes(const char *zone, void *dbdata, dns_sdlzallnodes_t *allnodes);

/*
 * dlz_newversion() is optional. It should be supplied if you want to
 * support dynamic updates.
 */
isc_result_t
dlz_newversion(const char *zone, void *dbdata, void **versionp);

/* 
 * dlz_closeversion() is optional, but must be supplied if you supply a
 * dlz_newversion() function
 */
void
dlz_closeversion(const char *zone, bool commit, void *dbdata,
		 void **versionp);

/*
 * dlz_configure() is optional, but must be supplied if you want to support
 * dynamic updates
 */
#if DLZ_DLOPEN_VERSION < 3
isc_result_t
dlz_configure(dns_view_t *view, void *dbdata);
#else /* DLZ_DLOPEN_VERSION >= 3 */
isc_result_t
dlz_configure(dns_view_t *view, dns_dlzdb_t *dlzdb, void *dbdata);
#endif /* DLZ_DLOPEN_VERSION */

/*
 * dlz_ssumatch() is optional, but must be supplied if you want to support
 * dynamic updates
 */
bool
dlz_ssumatch(const char *signer, const char *name, const char *tcpaddr,
	     const char *type, const char *key, uint32_t keydatalen,
	     uint8_t *keydata, void *dbdata);

/*
 * dlz_addrdataset() is optional, but must be supplied if you want to
 * support dynamic updates
 */
isc_result_t
dlz_addrdataset(const char *name, const char *rdatastr, void *dbdata,
		void *version);

/*
 * dlz_subrdataset() is optional, but must be supplied if you want to
 * support dynamic updates
 */
isc_result_t
dlz_subrdataset(const char *name, const char *rdatastr, void *dbdata,
		void *version);

/*
 * dlz_delrdataset() is optional, but must be supplied if you want to
 * support dynamic updates
 */
isc_result_t
dlz_delrdataset(const char *name, const char *type, void *dbdata,
		void *version);

#endif /* DLZ_MINIMAL_H */
