/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1996,1999 by Internet Software Consortium.
 *
 * 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 ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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.
 */

/* Imports */

#include "port_before.h"

#include <sys/types.h>

#include <netinet/in.h>
#include <arpa/nameser.h>

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

#include <isc/memcluster.h>
#include <irs.h>

#include "port_after.h"

#include "irs_p.h"
#include "gen_p.h"

/* Types */

struct pvt {
        struct irs_rule *       rules;
        struct irs_rule *       rule;
        struct __res_state *    res;
        void                    (*free_res)(void *);
};

/* Forward */

static void             nw_close(struct irs_nw*);
static struct nwent *   nw_next(struct irs_nw *);
static struct nwent *   nw_byname(struct irs_nw *, const char *, int);
static struct nwent *   nw_byaddr(struct irs_nw *, void *, int, int);
static void             nw_rewind(struct irs_nw *);
static void             nw_minimize(struct irs_nw *);
static struct __res_state * nw_res_get(struct irs_nw *this);
static void             nw_res_set(struct irs_nw *this,
                                   struct __res_state *res,
                                   void (*free_res)(void *));

static int              init(struct irs_nw *this);

/* Public */

struct irs_nw *
irs_gen_nw(struct irs_acc *this) {
        struct gen_p *accpvt = (struct gen_p *)this->private;
        struct irs_nw *nw;
        struct pvt *pvt;

        if (!(pvt = memget(sizeof *pvt))) {
                errno = ENOMEM;
                return (NULL);
        }
        memset(pvt, 0, sizeof *pvt);
        if (!(nw = memget(sizeof *nw))) {
                memput(pvt, sizeof *pvt);
                errno = ENOMEM;
                return (NULL);
        }
        memset(nw, 0x5e, sizeof *nw);
        pvt->rules = accpvt->map_rules[irs_nw];
        pvt->rule = pvt->rules;
        nw->private = pvt;
        nw->close = nw_close;
        nw->next = nw_next;
        nw->byname = nw_byname;
        nw->byaddr = nw_byaddr;
        nw->rewind = nw_rewind;
        nw->minimize = nw_minimize;
        nw->res_get = nw_res_get;
        nw->res_set = nw_res_set;
        return (nw);
}

/* Methods */

static void
nw_close(struct irs_nw *this) {
        struct pvt *pvt = (struct pvt *)this->private;

        nw_minimize(this);

        if (pvt->res && pvt->free_res)
                (*pvt->free_res)(pvt->res);

        memput(pvt, sizeof *pvt);
        memput(this, sizeof *this);
}

static struct nwent *
nw_next(struct irs_nw *this) {
        struct pvt *pvt = (struct pvt *)this->private;
        struct nwent *rval;
        struct irs_nw *nw;

        if (init(this) == -1)
                return(NULL);

        while (pvt->rule) {
                nw = pvt->rule->inst->nw;
                rval = (*nw->next)(nw);
                if (rval)
                        return (rval);
                if (!(pvt->rules->flags & IRS_CONTINUE))
                        break;
                pvt->rule = pvt->rule->next;
                if (pvt->rule) {
                        nw = pvt->rule->inst->nw;
                        (*nw->rewind)(nw);
                }
        }
        return (NULL);
}

static struct nwent *
nw_byname(struct irs_nw *this, const char *name, int type) {
        struct pvt *pvt = (struct pvt *)this->private;
        struct irs_rule *rule;
        struct nwent *rval;
        struct irs_nw *nw;

        if (init(this) == -1)
                return(NULL);

        for (rule = pvt->rules; rule; rule = rule->next) {
                nw = rule->inst->nw;
                RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
                rval = (*nw->byname)(nw, name, type);
                if (rval != NULL)
                        return (rval);
                if (pvt->res->res_h_errno != TRY_AGAIN &&
                    !(rule->flags & IRS_CONTINUE))
                        break;
        }
        return (NULL);
}

static struct nwent *
nw_byaddr(struct irs_nw *this, void *net, int length, int type) {
        struct pvt *pvt = (struct pvt *)this->private;
        struct irs_rule *rule;
        struct nwent *rval;
        struct irs_nw *nw;

        if (init(this) == -1)
                return(NULL);

        for (rule = pvt->rules; rule; rule = rule->next) {
                nw = rule->inst->nw;
                RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
                rval = (*nw->byaddr)(nw, net, length, type);
                if (rval != NULL)
                        return (rval);
                if (pvt->res->res_h_errno != TRY_AGAIN &&
                    !(rule->flags & IRS_CONTINUE))
                        break;
        }
        return (NULL);
}

static void
nw_rewind(struct irs_nw *this) {
        struct pvt *pvt = (struct pvt *)this->private;
        struct irs_nw *nw;

        pvt->rule = pvt->rules;
        if (pvt->rule) {
                nw = pvt->rule->inst->nw;
                (*nw->rewind)(nw);
        }
}

static void
nw_minimize(struct irs_nw *this) {
        struct pvt *pvt = (struct pvt *)this->private;
        struct irs_rule *rule;

        if (pvt->res)
                res_nclose(pvt->res);
        for (rule = pvt->rules; rule != NULL; rule = rule->next) {
                struct irs_nw *nw = rule->inst->nw;

                (*nw->minimize)(nw);
        }
}

static struct __res_state *
nw_res_get(struct irs_nw *this) {
        struct pvt *pvt = (struct pvt *)this->private;

        if (!pvt->res) {
                struct __res_state *res;
                res = (struct __res_state *)malloc(sizeof *res);
                if (!res) {
                        errno = ENOMEM;
                        return (NULL);
                }
                memset(res, 0, sizeof *res);
                nw_res_set(this, res, free);
        }

        return (pvt->res);
}

static void
nw_res_set(struct irs_nw *this, struct __res_state *res,
                void (*free_res)(void *)) {
        struct pvt *pvt = (struct pvt *)this->private;
        struct irs_rule *rule;

        if (pvt->res && pvt->free_res) {
                res_nclose(pvt->res);
                (*pvt->free_res)(pvt->res);
        }

        pvt->res = res;
        pvt->free_res = free_res;

        for (rule = pvt->rules; rule != NULL; rule = rule->next) {
                struct irs_nw *nw = rule->inst->nw;

                (*nw->res_set)(nw, pvt->res, NULL);
        }
}

static int
init(struct irs_nw *this) {
        struct pvt *pvt = (struct pvt *)this->private;

        if (!pvt->res && !nw_res_get(this))
                return (-1);
        if (((pvt->res->options & RES_INIT) == 0U) &&
            res_ninit(pvt->res) == -1)
                return (-1);
        return (0);
}

/*! \file */