/*      $OpenBSD: application.h,v 1.14 2025/11/27 10:17:19 martijn Exp $        */

/*
 * Copyright (c) 2021 Martijn van Duren <martijn@openbsd.org>
 *
 * 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.
 */

#include <sys/tree.h>

#include <ber.h>

#include <stdint.h>

#define APPL_OIDMAX 128 /* RFC 2578 Section 3.5 */
#define APPL_CONTEXTNAME_MAX 32 /* RFC 3415 vacmContextName */

/* Combination of RFC 3416 error-status and RFC 2741 res.error */
enum appl_error {
        APPL_ERROR_NOERROR              = 0,
        APPL_ERROR_TOOBIG               = 1,
        APPL_ERROR_NOSUCHNAME           = 2,
        APPL_ERROR_BADVALUE             = 3,
        APPL_ERROR_READONLY             = 4,
        APPL_ERROR_GENERR               = 5,
        APPL_ERROR_NOACCESS             = 6,
        APPL_ERROR_WRONGTYPE            = 7,
        APPL_ERROR_WRONGLENGTH          = 8,
        APPL_ERROR_WRONGENCODING        = 9,
        APPL_ERROR_WRONGVALUE           = 10,
        APPL_ERROR_NOCREATION           = 11,
        APPL_ERROR_INCONSISTENTVALUE    = 12,
        APPL_ERROR_RESOURCEUNAVAILABLE  = 13,
        APPL_ERROR_COMMITFAILED         = 14,
        APPL_ERROR_UNDOFAILED           = 15,
        APPL_ERROR_AUTHORIZATIONERROR   = 16,
        APPL_ERROR_NOTWRITABLE          = 17,
        APPL_ERROR_INCONSISTENTNAME     = 18,
        APPL_ERROR_OPENFAILED           = 256,
        APPL_ERROR_NOTOPEN              = 257,
        APPL_ERROR_INDEXWRONGTYPE       = 258,
        APPL_ERROR_INDEXALREADYALLOCATED= 259,
        APPL_ERROR_INDEXNONEAVAILABLE   = 260,
        APPL_ERROR_INDEXNOTALLOCATED    = 261,
        APPL_ERROR_UNSUPPORTEDCONTEXT   = 262,
        APPL_ERROR_DUPLICATEREGISTRATION= 263,
        APPL_ERROR_UNKNOWNREGISTRATION  = 264,
        APPL_ERROR_UNKNOWNAGENTCAPS     = 265,
        APPL_ERROR_PARSEERROR           = 266,
        APPL_ERROR_REQUESTDENIED        = 267,
        APPL_ERROR_PROCESSINGERROR      = 268
};

enum appl_exception {
        APPL_EXC_NOSUCHOBJECT           = 0,
        APPL_EXC_NOSUCHINSTANCE         = 1,
        APPL_EXC_ENDOFMIBVIEW           = 2
};

enum appl_close_reason {
        APPL_CLOSE_REASONOTHER          = 1,
        APPL_CLOSE_REASONPARSEERROR     = 2,
        APPL_CLOSE_REASONPROTOCOLERROR  = 3,
        APPL_CLOSE_REASONTIMEOUTS       = 4,
        APPL_CLOSE_REASONSHUTDOWN       = 5,
        APPL_CLOSE_REASONBYMANAGER      = 6
};

struct appl_varbind {
        int8_t av_include; /* RFC 2741 section 5.1 */
        struct ber_oid av_oid;
        struct ber_oid av_oid_end;
        struct ber_element *av_value;

        struct appl_varbind *av_next;
};

struct snmp_message;
enum snmp_version;
struct appl_backend;
struct appl_context;

struct appl_backend_functions {
        void (*ab_close)(struct appl_backend *, enum appl_close_reason);
        void (*ab_get)(struct appl_backend *, int32_t, int32_t, const char *,
            struct appl_varbind *);
        void (*ab_getnext)(struct appl_backend *, int32_t, int32_t, const char *,
            struct appl_varbind *);
        /*
         * RFC 3416 section 3: non-repeaters/max-repetitions = 0..max-bindings
         * max-bindings = (2^31)-1
         * RFC 2741 section 6.2.7: non-repeaters/max-repetitions = 2 bytes
         * Go for the lowest common denominator.
         */
        void (*ab_getbulk)(struct appl_backend *, int32_t, int32_t, int16_t,
            int16_t, const char *, struct appl_varbind *);
};

struct appl_backend {
        char *ab_name;
        void *ab_cookie;
        uint8_t ab_retries;
        int ab_range; /* Supports searchrange */
        struct appl_backend_functions *ab_fn;
        /*
         * Only store downstream requests: they reference upstream and when
         * downstream requests are done the upstream request is finalized.
         */
        RB_HEAD(appl_requests, appl_request_downstream) ab_requests;
};

void appl(void);
void appl_init(void);
void appl_shutdown(void);
struct appl_context *appl_context(const char *, int);
uint32_t appl_sysuptime(const char *);
enum appl_error appl_addagentcaps(const char *, struct ber_oid *, const char *,
    struct appl_backend *);
enum appl_error appl_removeagentcaps(const char *, struct ber_oid *,
    struct appl_backend *);
struct ber_element *appl_sysorlastchange(struct ber_oid *);
struct ber_element *appl_sysortable(struct ber_oid *);
struct ber_element *appl_sysortable_getnext(int8_t, struct ber_oid *);
struct ber_element *appl_targetmib(struct ber_oid *);
enum appl_error appl_register(const char *, uint32_t, uint8_t, struct ber_oid *,
    int, int, uint8_t, uint32_t, struct appl_backend *);
enum appl_error appl_unregister(const char *, uint8_t, struct ber_oid *,
    uint8_t, uint32_t, struct appl_backend *);
void appl_close(struct appl_backend *);
void appl_processpdu(struct snmp_message *, const char *,
    enum snmp_version , struct ber_element *);
void appl_response(struct appl_backend *, int32_t, enum appl_error, int16_t,
    struct appl_varbind *);
void appl_report(struct snmp_message *, int32_t, struct ber_oid *);
struct ber_element *appl_exception(enum appl_exception);

/* application_agentx.c */
void     appl_agentx(void);
void     appl_agentx_init(void);
void     appl_agentx_shutdown(void);
void     appl_agentx_backend(int);

/* application_blocklist.c */
void     appl_blocklist_init(void);
void     appl_blocklist_shutdown(void);

/* application_internal.c */
void     appl_internal_init(void);
void     appl_internal_shutdown(void);
const char *appl_internal_object_int(struct ber_oid *, int32_t);
const char *appl_internal_object_string(struct ber_oid *, char *);