/*-
 * Copyright (c) 2011-2025 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Christos Zoulas.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * NPF variables are used to build the intermediate representation (IR)
 * of the configuration grammar.  They represent primitive types (strings,
 * numbers, etc) as well as complex types (address and mask, table, etc).
 */

#include <sys/cdefs.h>
__RCSID("$NetBSD: npf_var.c,v 1.16 2025/08/20 11:03:59 joe Exp $");

#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define _NPFVAR_PRIVATE
#include "npfctl.h"

typedef struct npf_element {
        void *          e_data;
        unsigned        e_type;
        struct npf_element *e_next;
} npf_element_t;

struct npfvar {
        char *          v_key;
        npf_element_t * v_elements;
        npf_element_t * v_last;
        size_t          v_count;
        void *          v_next;
};

static npfvar_t *       var_list = NULL;
static size_t           var_num = 0;

npfvar_t *
npfvar_create(void)
{
        npfvar_t *vp = ecalloc(1, sizeof(*vp));
        var_num++;
        return vp;
}

npfvar_t *
npfvar_lookup(const char *key)
{
        for (npfvar_t *it = var_list; it != NULL; it = it->v_next)
                if (strcmp(it->v_key, key) == 0)
                        return it;
        return NULL;
}

const char *
npfvar_type(size_t t)
{
        if (t >= __arraycount(npfvar_types)) {
                return "unknown";
        }
        return npfvar_types[t];
}

void
npfvar_add(npfvar_t *vp, const char *name)
{
        vp->v_key = estrdup(name);
        vp->v_next = var_list;
        var_list = vp;
}

npfvar_t *
npfvar_create_element(unsigned type, const void *data, size_t len)
{
        npfvar_t *vp = npfvar_create();
        return npfvar_add_element(vp, type, data, len);
}

npfvar_t *
npfvar_create_from_string(unsigned type, const char *string)
{
        return npfvar_create_element(type, string, strlen(string) + 1);
}

npfvar_t *
npfvar_add_element(npfvar_t *vp, unsigned type, const void *data, size_t len)
{
        npf_element_t *el;

        el = ecalloc(1, sizeof(*el));
        el->e_data = ecalloc(1, len);
        el->e_type = type;
        memcpy(el->e_data, data, len);

        /* Preserve the order of insertion. */
        if (vp->v_elements == NULL) {
                vp->v_elements = el;
        } else {
                vp->v_last->e_next = el;
        }
        vp->v_last = el;
        vp->v_count++;
        return vp;
}

npfvar_t *
npfvar_add_elements(npfvar_t *vp, npfvar_t *vp2)
{
        if (vp2 == NULL)
                return vp;
        if (vp == NULL)
                return vp2;

        if (vp->v_elements == NULL) {
                if (vp2->v_elements) {
                        vp->v_elements = vp2->v_elements;
                }
        } else if (vp2->v_elements) {
                vp->v_last->e_next = vp2->v_elements;
        }
        if (vp2->v_elements) {
                vp->v_last = vp2->v_last;
                vp->v_count += vp2->v_count;
                vp2->v_elements = NULL;
                vp2->v_count = 0;
                vp2->v_last = NULL;
        }
        npfvar_destroy(vp2);
        return vp;
}

static void
npfvar_free_elements(npf_element_t *el)
{
        if (el == NULL)
                return;
        npfvar_free_elements(el->e_next);
        free(el->e_data);
        free(el);
}

void
npfvar_destroy(npfvar_t *vp)
{
        npfvar_free_elements(vp->v_elements);
        free(vp->v_key);
        free(vp);
        var_num--;
}

char *
npfvar_expand_string(const npfvar_t *vp)
{
        if (npfvar_get_count(vp) != 1) {
                yyerror("variable '%s' has multiple elements", vp->v_key);
                return NULL;
        }
        return npfvar_get_data(vp, NPFVAR_STRING, 0);
}

uint32_t
npfvar_expand_number(const npfvar_t *vp)
{
        uint32_t *number;
        if (npfvar_get_count(vp) != 1) {
                yyerror("variable '%s' has multiple elements", vp->v_key);
        }
        number =  (uint32_t *)npfvar_get_data(vp, NPFVAR_NUM, 0);
        return *number;
}

void
npf_var_rid(char *var_id, rid_parser parser, uint32_t *rid, const char *ridt)
{
        npfvar_t *vp = npfvar_lookup(var_id);
        int type = npfvar_get_type(vp, 0);
        char *rid_type;

        switch (type) {
        case NPFVAR_IDENTIFIER:
        case NPFVAR_STRING:
                rid_type = npfvar_expand_string(vp);
                if (parser(rid_type, rid) == -1) {
                        yyerror("unknown %s %s", var_id, ridt);
                }
                break;
        case NPFVAR_NUM:
                *rid = npfvar_expand_number(vp);
                break;
        case -1:
                yyerror("undefined variable '%s'", var_id);
                break;
        default:
                yyerror("wrong variable '%s' type '%s' for %s id",
                        var_id, npfvar_type(type), ridt);
                break;
        }
}

size_t
npfvar_get_count(const npfvar_t *vp)
{
        return vp ? vp->v_count : 0;
}

static npf_element_t *
npfvar_get_element(const npfvar_t *vp, size_t idx, size_t level)
{
        npf_element_t *el;

        /*
         * Verify the parameters.
         */
        if (vp == NULL) {
                return NULL;
        }
        if (level >= var_num) {
                yyerror("circular dependency for variable '%s'", vp->v_key);
                return NULL;
        }
        if (vp->v_count <= idx) {
                yyerror("variable '%s' has only %zu elements, requested %zu",
                    vp->v_key, vp->v_count, idx);
                return NULL;
        }

        /*
         * Get the element at the given index.
         */
        el = vp->v_elements;
        while (idx--) {
                el = el->e_next;
        }

        return el;
}

/*
 * now we can return a VAR_ID to be fully resolved
 * and fleshed out in filter rules in both type and data
 */
void *
npfvar_getfilt_data(const npfvar_t *vp, unsigned type, size_t idx)
{
        npf_element_t *el = npfvar_get_element(vp, idx, 0);

        if (!el)
                return NULL;

        if (el && NPFVAR_TYPE(el->e_type) != NPFVAR_TYPE(type)) {
                yyerror("variable '%s' element %zu "
                    "is of type '%s' rather than '%s'", vp->v_key,
                    idx, npfvar_type(el->e_type), npfvar_type(type));
                return NULL;
        }
        return el->e_data;
}

int
npfvar_getfilt_type(const npfvar_t *vp, size_t idx)
{
        npf_element_t *el = npfvar_get_element(vp, idx, 0);
        return el ? (int)el->e_type : -1;
}

int
npfvar_get_type(const npfvar_t *vp, size_t idx)
{
        npf_element_t *el = npfvar_get_element(vp, idx, 0);

        if (!el)
                return -1;

        /*
         * Resolve if it is a reference to another variable.
         */
        if (el->e_type == NPFVAR_VAR_ID) {
                const npfvar_t *rvp = npfvar_lookup(el->e_data);
                if (rvp == NULL)
                        yyerror("variable not found");

                return npfvar_get_type(rvp, idx);
        }
        return (int)el->e_type;
}

void *
npfvar_get_data(const npfvar_t *vp, unsigned type, size_t idx)
{
        npf_element_t *el = npfvar_get_element(vp, idx, 0);

        if (!el)
                return NULL;

        /*
         * Resolve if it is a reference to another variable.
         */
        if (el->e_type == NPFVAR_VAR_ID) {
                const npfvar_t *rvp = npfvar_lookup(el->e_data);
                if (rvp == NULL)
                        yyerror("variable not found");

                return npfvar_get_data(rvp, type, idx);
        }

        if (el && NPFVAR_TYPE(el->e_type) != NPFVAR_TYPE(type)) {
                yyerror("variable '%s' element %zu "
                    "is of type '%s' rather than '%s'", vp->v_key,
                    idx, npfvar_type(el->e_type), npfvar_type(type));
                return NULL;
        }
        return el->e_data;
}