/*      $OpenBSD: unpack_dns.h,v 1.2 2021/06/14 17:58:16 eric Exp $     */

/*
 * Copyright (c) 2011-2014 Eric Faurot <eric@faurot.net>
 *
 * 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 <netinet/in.h>

#include <arpa/nameser.h>

struct unpack {
        const char      *buf;
        size_t           len;
        size_t           offset;
        const char      *err;
};

struct dns_header {
        uint16_t        id;
        uint16_t        flags;
        uint16_t        qdcount;
        uint16_t        ancount;
        uint16_t        nscount;
        uint16_t        arcount;
};

struct dns_query {
        char            q_dname[MAXDNAME];
        uint16_t        q_type;
        uint16_t        q_class;
};

struct dns_rr {
        char            rr_dname[MAXDNAME];
        uint16_t        rr_type;
        uint16_t        rr_class;
        uint32_t        rr_ttl;
        union {
                struct {
                        char    cname[MAXDNAME];
                } cname;
                struct {
                        uint16_t        preference;
                        char            exchange[MAXDNAME];
                } mx;
                struct {
                        char    nsname[MAXDNAME];
                } ns;
                struct {
                        char    ptrname[MAXDNAME];
                } ptr;
                struct {
                        char            mname[MAXDNAME];
                        char            rname[MAXDNAME];
                        uint32_t        serial;
                        uint32_t        refresh;
                        uint32_t        retry;
                        uint32_t        expire;
                        uint32_t        minimum;
                } soa;
                struct {
                        struct in_addr  addr;
                } in_a;
                struct {
                        struct in6_addr addr6;
                } in_aaaa;
                struct {
                        uint16_t         rdlen;
                        const void      *rdata;
                } other;
        } rr;
};

void     unpack_init(struct unpack *, const char *, size_t);
int      unpack_header(struct unpack *, struct dns_header *);
int      unpack_rr(struct unpack *, struct dns_rr *);
int      unpack_query(struct unpack *, struct dns_query *);
char    *print_dname(const char *, char *, size_t);
ssize_t  dname_expand(const unsigned char *, size_t, size_t, size_t *,
            char *, size_t);