/*      $OpenBSD: name2id.c,v 1.1 2007/01/08 13:01:10 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 "ripd.h"

#define IDVAL_MAX       50000

struct n2id_label {
        TAILQ_ENTRY(n2id_label)  entry;
        char                    *name;
        u_int16_t                id;
        int                      ref;
};

TAILQ_HEAD(n2id_labels, n2id_label);

u_int16_t        _name2id(struct n2id_labels *, const char *);
const char      *_id2name(struct n2id_labels *, u_int16_t);
void             _unref(struct n2id_labels *, u_int16_t);
void             _ref(struct n2id_labels *, u_int16_t);

struct n2id_labels      rt_labels = TAILQ_HEAD_INITIALIZER(rt_labels);

u_int16_t
rtlabel_name2id(const char *name)
{
        return (_name2id(&rt_labels, name));
}

const char *
rtlabel_id2name(u_int16_t id)
{
        return (_id2name(&rt_labels, id));
}

void
rtlabel_unref(u_int16_t id)
{
        _unref(&rt_labels, id);
}

/*
void
rtlabel_ref(u_int16_t id)
{
        _ref(&rt_labels, id);
}
*/

u_int16_t
_name2id(struct n2id_labels *head, const char *name)
{
        struct n2id_label       *label, *p = NULL;
        u_int16_t                new_id = 1;

        if (!name[0]) {
                errno = EINVAL;
                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.
         */

        if (!TAILQ_EMPTY(head))
                for (p = TAILQ_FIRST(head); p != NULL &&
                    p->id == new_id; p = TAILQ_NEXT(p, entry))
                        new_id = p->id + 1;

        if (new_id > IDVAL_MAX) {
                errno = ERANGE;
                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, u_int16_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, u_int16_t id)
{
        struct n2id_label       *p, *next;

        if (id == 0)
                return;

        for (p = TAILQ_FIRST(head); p != NULL; p = next) {
                next = TAILQ_NEXT(p, entry);
                if (id == p->id) {
                        if (--p->ref == 0) {
                                TAILQ_REMOVE(head, p, entry);
                                free(p->name);
                                free(p);
                        }
                        break;
                }
        }
}

void
_ref(struct n2id_labels *head, u_int16_t id)
{
        struct n2id_label       *label;

        if (id == 0)
                return;

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