/*      $OpenBSD: getrrsetbyname_async.c,v 1.16 2026/06/23 17:49:09 florian Exp $       */
/*
 * Copyright (c) 2012 Eric Faurot <eric@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/types.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <netdb.h>

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

#include "asr_private.h"

static int getrrsetbyname_async_run(struct asr_query *, struct asr_result *);
static void get_response(struct asr_result *, const char *, int);

struct asr_query *
getrrsetbyname_async(const char *hostname, unsigned int rdclass,
    unsigned int rdtype, unsigned int flags, void *asr)
{
        struct asr_ctx   *ac;
        struct asr_query *as;

        ac = _asr_use_resolver(asr);
        if ((as = _asr_async_new(ac, ASR_GETRRSETBYNAME)) == NULL)
                goto abort; /* errno set */
        as->as_run = getrrsetbyname_async_run;

        as->as.rrset.flags = flags;
        as->as.rrset.class = rdclass;
        as->as.rrset.type = rdtype;
        as->as.rrset.name = strdup(hostname);
        if (as->as.rrset.name == NULL)
                goto abort; /* errno set */

        _asr_ctx_unref(ac);
        return (as);
    abort:
        if (as)
                _asr_async_free(as);

        _asr_ctx_unref(ac);
        return (NULL);
}
DEF_WEAK(getrrsetbyname_async);

static int
getrrsetbyname_async_run(struct asr_query *as, struct asr_result *ar)
{
    next:
        switch (as->as_state) {

        case ASR_STATE_INIT:

                /* Check for invalid class and type. */
                if (as->as.rrset.class > 0xffff || as->as.rrset.type > 0xffff) {
                        ar->ar_rrset_errno = ERRSET_INVAL;
                        async_set_state(as, ASR_STATE_HALT);
                        break;
                }

                /* Do not allow queries of class or type ANY. */
                if (as->as.rrset.class == 0xff || as->as.rrset.type == 0xff) {
                        ar->ar_rrset_errno = ERRSET_INVAL;
                        async_set_state(as, ASR_STATE_HALT);
                        break;
                }

                /* Do not allow flags yet, unimplemented. */
                if (as->as.rrset.flags) {
                        ar->ar_rrset_errno = ERRSET_INVAL;
                        async_set_state(as, ASR_STATE_HALT);
                        break;
                }

                /* Create a delegate the lookup to a subquery. */
                as->as_subq = _res_query_async_ctx(
                    as->as.rrset.name,
                    as->as.rrset.class,
                    as->as.rrset.type,
                    as->as_ctx);
                if (as->as_subq == NULL) {
                        ar->ar_rrset_errno = ERRSET_FAIL;
                        async_set_state(as, ASR_STATE_HALT);
                        break;
                }

                async_set_state(as, ASR_STATE_SUBQUERY);
                break;

        case ASR_STATE_SUBQUERY:

                if ((asr_run(as->as_subq, ar)) == ASYNC_COND)
                        return (ASYNC_COND);

                as->as_subq = NULL;

                /* No packet received.*/
                if (ar->ar_datalen == -1) {
                        switch (ar->ar_h_errno) {
                        case HOST_NOT_FOUND:
                                ar->ar_rrset_errno = ERRSET_NONAME;
                                break;
                        case NO_DATA:
                                ar->ar_rrset_errno = ERRSET_NODATA;
                                break;
                        default:
                                ar->ar_rrset_errno = ERRSET_FAIL;
                                break;
                        }
                        async_set_state(as, ASR_STATE_HALT);
                        break;
                }

                /* Got a packet but no answer. */
                if (ar->ar_count == 0) {
                        free(ar->ar_data);
                        switch (ar->ar_rcode) {
                        case NXDOMAIN:
                                ar->ar_rrset_errno = ERRSET_NONAME;
                                break;
                        case NOERROR:
                                ar->ar_rrset_errno = ERRSET_NODATA;
                                break;
                        default:
                                ar->ar_rrset_errno = ERRSET_FAIL;
                                break;
                        }
                        async_set_state(as, ASR_STATE_HALT);
                        break;
                }

                get_response(ar, ar->ar_data, ar->ar_datalen);
                free(ar->ar_data);
                async_set_state(as, ASR_STATE_HALT);
                break;

        case ASR_STATE_HALT:
                if (ar->ar_rrset_errno)
                        ar->ar_rrsetinfo = NULL;
                return (ASYNC_DONE);

        default:
                ar->ar_rrset_errno = ERRSET_FAIL;
                async_set_state(as, ASR_STATE_HALT);
                break;
        }
        goto next;
}

/* The rest of this file is taken from the original implementation. */

/* $OpenBSD: getrrsetbyname_async.c,v 1.16 2026/06/23 17:49:09 florian Exp $ */

/*
 * Copyright (c) 2001 Jakob Schlyter. All rights reserved.
 *
 * 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 AUTHOR ``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 AUTHOR 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.
 */

/*
 * Portions Copyright (c) 1999-2001 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 INTERNET SOFTWARE CONSORTIUM
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * INTERNET SOFTWARE CONSORTIUM 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.
 */

#define MAXPACKET 1024*64

struct dns_query {
        char                    *name;
        u_int16_t               type;
        u_int16_t               class;
        struct dns_query        *next;
};

struct dns_rr {
        char                    *name;
        u_int16_t               type;
        u_int16_t               class;
        u_int32_t               ttl;
        u_int16_t               size;
        void                    *rdata;
        struct dns_rr           *next;
};

struct dns_response {
        HEADER                  header;
        struct dns_query        *query;
        struct dns_rr           *answer;
        struct dns_rr           *authority;
        struct dns_rr           *additional;
};

static struct dns_response *parse_dns_response(const u_char *, int);
static struct dns_query *parse_dns_qsection(const u_char *, int,
    const u_char **, int);
static struct dns_rr *parse_dns_rrsection(const u_char *, int, const u_char **,
    int);

static void free_dns_query(struct dns_query *);
static void free_dns_rr(struct dns_rr *);
static void free_dns_response(struct dns_response *);

static int count_dns_rr(struct dns_rr *, u_int16_t, u_int16_t);

static void
get_response(struct asr_result *ar, const char *pkt, int pktlen)
{
        struct rrsetinfo *rrset = NULL;
        struct dns_response *response = NULL;
        struct dns_rr *rr;
        struct rdatainfo *rdata;
        unsigned int index_ans, index_sig;

        /* parse result */
        response = parse_dns_response(pkt, pktlen);
        if (response == NULL) {
                ar->ar_rrset_errno = ERRSET_FAIL;
                goto fail;
        }

        if (response->header.qdcount != 1) {
                ar->ar_rrset_errno = ERRSET_FAIL;
                goto fail;
        }

        /* initialize rrset */
        rrset = calloc(1, sizeof(struct rrsetinfo));
        if (rrset == NULL) {
                ar->ar_rrset_errno = ERRSET_NOMEMORY;
                goto fail;
        }
        rrset->rri_rdclass = response->query->class;
        rrset->rri_rdtype = response->query->type;
        rrset->rri_ttl = response->answer->ttl;
        rrset->rri_nrdatas = response->header.ancount;

        /* check for authenticated data */
        if (response->header.ad == 1)
                rrset->rri_flags |= RRSET_VALIDATED;

        /* copy name from answer section */
        rrset->rri_name = strdup(response->answer->name);
        if (rrset->rri_name == NULL) {
                ar->ar_rrset_errno = ERRSET_NOMEMORY;
                goto fail;
        }

        /* count answers */
        rrset->rri_nrdatas = count_dns_rr(response->answer, rrset->rri_rdclass,
            rrset->rri_rdtype);
        rrset->rri_nsigs = count_dns_rr(response->answer, rrset->rri_rdclass,
            T_RRSIG);

        /* allocate memory for answers */
        rrset->rri_rdatas = calloc(rrset->rri_nrdatas,
            sizeof(struct rdatainfo));
        if (rrset->rri_rdatas == NULL) {
                ar->ar_rrset_errno = ERRSET_NOMEMORY;
                goto fail;
        }

        /* allocate memory for signatures */
        rrset->rri_sigs = calloc(rrset->rri_nsigs, sizeof(struct rdatainfo));
        if (rrset->rri_sigs == NULL) {
                ar->ar_rrset_errno = ERRSET_NOMEMORY;
                goto fail;
        }

        /* copy answers & signatures */
        for (rr = response->answer, index_ans = 0, index_sig = 0;
            rr; rr = rr->next) {

                rdata = NULL;

                if (rr->class == rrset->rri_rdclass &&
                    rr->type  == rrset->rri_rdtype)
                        rdata = &rrset->rri_rdatas[index_ans++];

                if (rr->class == rrset->rri_rdclass &&
                    rr->type  == T_RRSIG)
                        rdata = &rrset->rri_sigs[index_sig++];

                if (rdata) {
                        rdata->rdi_length = rr->size;
                        if (rr->size != 0) {
                                rdata->rdi_data = malloc(rr->size);
                                if (rdata->rdi_data == NULL) {
                                        ar->ar_rrset_errno = ERRSET_NOMEMORY;
                                        goto fail;
                                }
                                memcpy(rdata->rdi_data, rr->rdata, rr->size);
                        }
                }
        }
        free_dns_response(response);

        ar->ar_rrsetinfo = rrset;
        ar->ar_rrset_errno = ERRSET_SUCCESS;
        return;

fail:
        if (rrset != NULL)
                freerrset(rrset);
        if (response != NULL)
                free_dns_response(response);
}

/*
 * DNS response parsing routines
 */
static struct dns_response *
parse_dns_response(const u_char *answer, int size)
{
        struct dns_response *resp;
        const u_char *cp;

        if (size <= HFIXEDSZ)
                return (NULL);

        /* allocate memory for the response */
        resp = calloc(1, sizeof(*resp));
        if (resp == NULL)
                return (NULL);

        /* initialize current pointer */
        cp = answer;

        /* copy header */
        memcpy(&resp->header, cp, HFIXEDSZ);
        cp += HFIXEDSZ;

        /* fix header byte order */
        resp->header.qdcount = ntohs(resp->header.qdcount);
        resp->header.ancount = ntohs(resp->header.ancount);
        resp->header.nscount = ntohs(resp->header.nscount);
        resp->header.arcount = ntohs(resp->header.arcount);

        /* there must be at least one query */
        if (resp->header.qdcount < 1) {
                free_dns_response(resp);
                return (NULL);
        }

        /* parse query section */
        resp->query = parse_dns_qsection(answer, size, &cp,
            resp->header.qdcount);
        if (resp->header.qdcount && resp->query == NULL) {
                free_dns_response(resp);
                return (NULL);
        }

        /* parse answer section */
        resp->answer = parse_dns_rrsection(answer, size, &cp,
            resp->header.ancount);
        if (resp->header.ancount && resp->answer == NULL) {
                free_dns_response(resp);
                return (NULL);
        }

        /* parse authority section */
        resp->authority = parse_dns_rrsection(answer, size, &cp,
            resp->header.nscount);
        if (resp->header.nscount && resp->authority == NULL) {
                free_dns_response(resp);
                return (NULL);
        }

        /* parse additional section */
        resp->additional = parse_dns_rrsection(answer, size, &cp,
            resp->header.arcount);
        if (resp->header.arcount && resp->additional == NULL) {
                free_dns_response(resp);
                return (NULL);
        }

        return (resp);
}

static struct dns_query *
parse_dns_qsection(const u_char *answer, int size, const u_char **cp, int count)
{
        struct dns_query *head, *curr, *prev;
        int i, length;
        char name[MAXDNAME];

#define NEED(need) \
        do { \
                if (*cp + need > answer + size) \
                        goto fail; \
        } while (0)

        for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
                if (*cp >= answer + size) {
 fail:
                        free_dns_query(head);
                        return (NULL);
                }
                /* allocate and initialize struct */
                curr = calloc(1, sizeof(struct dns_query));
                if (curr == NULL)
                        goto fail;
                if (head == NULL)
                        head = curr;
                if (prev != NULL)
                        prev->next = curr;

                /* name */
                length = dn_expand(answer, answer + size, *cp, name,
                    sizeof(name));
                if (length < 0) {
                        free_dns_query(head);
                        return (NULL);
                }
                curr->name = strdup(name);
                if (curr->name == NULL) {
                        free_dns_query(head);
                        return (NULL);
                }
                NEED(length);
                *cp += length;

                /* type */
                NEED(INT16SZ);
                curr->type = _getshort(*cp);
                *cp += INT16SZ;

                /* class */
                NEED(INT16SZ);
                curr->class = _getshort(*cp);
                *cp += INT16SZ;
        }
#undef NEED

        return (head);
}

static struct dns_rr *
parse_dns_rrsection(const u_char *answer, int size, const u_char **cp,
    int count)
{
        struct dns_rr *head, *curr, *prev;
        int i, length;
        char name[MAXDNAME];

#define NEED(need) \
        do { \
                if (*cp + need > answer + size) \
                        goto fail; \
        } while (0)

        for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
                if (*cp >= answer + size) {
 fail:
                        free_dns_rr(head);
                        return (NULL);
                }

                /* allocate and initialize struct */
                curr = calloc(1, sizeof(struct dns_rr));
                if (curr == NULL)
                        goto fail;
                if (head == NULL)
                        head = curr;
                if (prev != NULL)
                        prev->next = curr;

                /* name */
                length = dn_expand(answer, answer + size, *cp, name,
                    sizeof(name));
                if (length < 0) {
                        free_dns_rr(head);
                        return (NULL);
                }
                curr->name = strdup(name);
                if (curr->name == NULL) {
                        free_dns_rr(head);
                        return (NULL);
                }
                NEED(length);
                *cp += length;

                /* type */
                NEED(INT16SZ);
                curr->type = _getshort(*cp);
                *cp += INT16SZ;

                /* class */
                NEED(INT16SZ);
                curr->class = _getshort(*cp);
                *cp += INT16SZ;

                /* ttl */
                NEED(INT32SZ);
                curr->ttl = _getlong(*cp);
                *cp += INT32SZ;

                /* rdata size */
                NEED(INT16SZ);
                curr->size = _getshort(*cp);
                *cp += INT16SZ;

                /* rdata itself */
                NEED(curr->size);
                if (curr->size != 0) {
                        if ((curr->rdata = malloc(curr->size)) == NULL) {
                                free_dns_rr(head);
                                return (NULL);
                        }
                        memcpy(curr->rdata, *cp, curr->size);
                }
                *cp += curr->size;
        }
#undef NEED

        return (head);
}

static void
free_dns_query(struct dns_query *p)
{
        struct dns_query *next;

        while (p != NULL) {
                next = p->next;
                free(p->name);
                free(p);
                p = next;
        }
}

static void
free_dns_rr(struct dns_rr *p)
{
        struct dns_rr *next;

        while (p != NULL) {
                next = p->next;
                free(p->name);
                free(p->rdata);
                free(p);
                p = next;
        }
}

static void
free_dns_response(struct dns_response *p)
{
        if (p == NULL)
                return;

        free_dns_query(p->query);
        free_dns_rr(p->answer);
        free_dns_rr(p->authority);
        free_dns_rr(p->additional);
        free(p);
}

static int
count_dns_rr(struct dns_rr *p, u_int16_t class, u_int16_t type)
{
        int n = 0;

        while (p) {
                if (p->class == class && p->type == type)
                        n++;
                p = p->next;
        }

        return (n);
}