/*      $OpenBSD: name2id.c,v 1.13 2025/02/12 16:49:56 claudio Exp $ */

/*
 * Copyright (c) 2004, 2005 Henning Brauer <henning@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 MIND, 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/types.h>
#include <sys/socket.h>

#include <net/route.h>

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

#include "bgpd.h"

#define IDVAL_MAX       50000

struct n2id_label {
        TAILQ_ENTRY(n2id_label)  entry;
        char                    *name;
        uint16_t                 id;
        int                      ref;
};

TAILQ_HEAD(n2id_labels, n2id_label);

uint16_t         _name2id(struct n2id_labels *, const char *);
const char      *_id2name(struct n2id_labels *, uint16_t);
void             _unref(struct n2id_labels *, uint16_t);
uint16_t         _ref(struct n2id_labels *, uint16_t);

struct n2id_labels      rt_labels = TAILQ_HEAD_INITIALIZER(rt_labels);
struct n2id_labels      pftable_labels = TAILQ_HEAD_INITIALIZER(pftable_labels);

uint16_t
rtlabel_name2id(const char *name)
{
        return (_name2id(&rt_labels, name));
}

const char *
rtlabel_id2name(uint16_t id)
{
        return (_id2name(&rt_labels, id));
}

void
rtlabel_unref(uint16_t id)
{
        _unref(&rt_labels, id);
}

uint16_t
rtlabel_ref(uint16_t id)
{
        return (_ref(&rt_labels, id));
}

uint16_t
pftable_name2id(const char *name)
{
        return (_name2id(&pftable_labels, name));
}

const char *
pftable_id2name(uint16_t id)
{
        return (_id2name(&pftable_labels, id));
}

void
pftable_unref(uint16_t id)
{
        _unref(&pftable_labels, id);
}

uint16_t
pftable_ref(uint16_t id)
{
        return (_ref(&pftable_labels, id));
}

/*
 * Try to convert a name into id. If something fails 0 is returned which
 * is the ID of the empty label.
 */
uint16_t
_name2id(struct n2id_labels *head, const char *name)
{
        struct n2id_label       *label, *p = NULL;
        uint16_t                 new_id = 1;

        if (!name[0])
                return (0);

        TAILQ_FOREACH(label, head, entry)
                if (strcmp(name, label->name) == 0) {
                        label->ref++;
                        return (label->id);
                }

        /*
         * to avoid fragmentation, we do a linear search from the beginning
         * and take the first free slot we find. if there is none or the list
         * is empty, append a new entry at the end.
         */

        TAILQ_FOREACH(p, head, entry) {
                if (p->id != new_id)
                        break;
                new_id++;
        }

        if (new_id > IDVAL_MAX)
                return (0);

        if ((label = calloc(1, sizeof(struct n2id_label))) == NULL)
                return (0);
        if ((label->name = strdup(name)) == NULL) {
                free(label);
                return (0);
        }
        label->id = new_id;
        label->ref++;

        if (p != NULL)  /* insert new entry before p */
                TAILQ_INSERT_BEFORE(p, label, entry);
        else            /* either list empty or no free slot in between */
                TAILQ_INSERT_TAIL(head, label, entry);

        return (label->id);
}

const char *
_id2name(struct n2id_labels *head, uint16_t id)
{
        struct n2id_label       *label;

        if (id == 0)
                return ("");

        TAILQ_FOREACH(label, head, entry)
                if (label->id == id)
                        return (label->name);

        return ("");
}

void
_unref(struct n2id_labels *head, uint16_t id)
{
        struct n2id_label       *p, *next;

        if (id == 0)
                return;

        TAILQ_FOREACH_SAFE(p, head, entry, next) {
                if (id == p->id) {
                        if (--p->ref == 0) {
                                TAILQ_REMOVE(head, p, entry);
                                free(p->name);
                                free(p);
                        }
                        break;
                }
        }
}

uint16_t
_ref(struct n2id_labels *head, uint16_t id)
{
        struct n2id_label       *label;

        if (id == 0)
                return (0);

        TAILQ_FOREACH(label, head, entry)
                if (label->id == id) {
                        ++label->ref;
                        return (id);
                }

        /* id not found, treat like no id  */
        return (0);
}