/*      $OpenBSD: asr_private.h,v 1.49 2023/11/20 12:15:16 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 <stdio.h>

#define QR_MASK         (0x1 << 15)
#define OPCODE_MASK     (0xf << 11)
#define AA_MASK         (0x1 << 10)
#define TC_MASK         (0x1 <<  9)
#define RD_MASK         (0x1 <<  8)
#define RA_MASK         (0x1 <<  7)
#define Z_MASK          (0x1 <<  6)
#define AD_MASK         (0x1 <<  5)
#define CD_MASK         (0x1 <<  4)
#define RCODE_MASK      (0xf)

#define OPCODE(v)       ((v) & OPCODE_MASK)
#define RCODE(v)        ((v) & RCODE_MASK)


struct asr_pack {
        char            *buf;
        size_t           len;
        size_t           offset;
        int              err;
};

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

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

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

struct asr_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;
};


#define ASR_MAXNS       5
#define ASR_MAXDB       3
#define ASR_MAXDOM      10

enum async_type {
        ASR_SEND,
        ASR_SEARCH,
        ASR_GETRRSETBYNAME,
        ASR_GETHOSTBYNAME,
        ASR_GETHOSTBYADDR,
        ASR_GETADDRINFO,
        ASR_GETNAMEINFO,
};

#define ASR_DB_FILE     'f'
#define ASR_DB_DNS      'b'

struct asr_ctx {
        int              ac_refcount;
        int              ac_options;
        int              ac_ndots;
        char            *ac_domain;
        int              ac_domcount;
        char            *ac_dom[ASR_MAXDOM];
        int              ac_dbcount;
        char             ac_db[ASR_MAXDB + 1];
        int              ac_family[3];

        int              ac_nscount;
        int              ac_nstimeout;
        int              ac_nsretries;
        struct sockaddr *ac_ns[ASR_MAXNS];

};

struct asr {
        pid_t            a_pid;
        time_t           a_mtime;
        time_t           a_rtime;
        struct asr_ctx  *a_ctx;
};

#define ASYNC_COND              0
#define ASYNC_DONE              1

#define ASYNC_DOM_FQDN          0x00000001
#define ASYNC_DOM_NDOTS         0x00000002
#define ASYNC_DOM_DOMAIN        0x00000004
#define ASYNC_DOM_ASIS          0x00000008

#define ASYNC_NODATA            0x00000100
#define ASYNC_AGAIN             0x00000200

#define ASYNC_GETNET            0x00001000
#define ASYNC_EXTOBUF           0x00002000

#define ASYNC_NO_INET           0x00010000
#define ASYNC_NO_INET6          0x00020000

struct asr_query {
        int             (*as_run)(struct asr_query *, struct asr_result *);
        struct asr_ctx  *as_ctx;
        int              as_type;
        int              as_flags;
        int              as_state;

        /* cond */
        int              as_timeout;
        int              as_fd;
        struct asr_query *as_subq;

        /* loop indices in ctx */
        int              as_dom_step;
        int              as_dom_idx;
        int              as_dom_flags;
        int              as_family_idx;
        int              as_db_idx;

        int              as_count;

        union {
                struct {
                        uint16_t         reqid;
                        int              class;
                        int              type;
                        char            *dname;         /* not fqdn! */
                        int              rcode;         /* response code */
                        int              ancount;       /* answer count */

                        int              nsidx;
                        int              nsloop;

                        /* io buffers for query/response */
                        unsigned char   *obuf;
                        size_t           obuflen;
                        size_t           obufsize;
                        unsigned char   *ibuf;
                        size_t           ibuflen;
                        size_t           ibufsize;
                        size_t           datalen; /* for tcp io */
                        uint16_t         pktlen;
                } dns;

                struct {
                        int              class;
                        int              type;
                        char            *name;
                        int              saved_h_errno;
                } search;

                struct {
                        int              flags;
                        int              class;
                        int              type;
                        char            *name;
                } rrset;

                struct {
                        char            *name;
                        int              family;
                        char             addr[16];
                        int              addrlen;
                        int              subq_h_errno;
                } hostnamadr;

                struct {
                        char            *hostname;
                        char            *servname;
                        int              port_tcp;
                        int              port_udp;
                        union {
                                struct sockaddr         sa;
                                struct sockaddr_in      sain;
                                struct sockaddr_in6     sain6;
                        }                sa;

                        struct addrinfo  hints;
                        char            *fqdn;
                        struct addrinfo *aifirst;
                        struct addrinfo *ailast;
                } ai;

                struct {
                        char            *hostname;
                        char            *servname;
                        size_t           hostnamelen;
                        size_t           servnamelen;
                        union {
                                struct sockaddr         sa;
                                struct sockaddr_in      sain;
                                struct sockaddr_in6     sain6;
                        }                sa;
                        int              flags;
                } ni;
#define MAXTOKEN 10
        } as;

};

#define AS_DB(p) ((p)->as_ctx->ac_db[(p)->as_db_idx - 1])
#define AS_FAMILY(p) ((p)->as_ctx->ac_family[(p)->as_family_idx])

enum asr_state {
        ASR_STATE_INIT,
        ASR_STATE_NEXT_DOMAIN,
        ASR_STATE_NEXT_DB,
        ASR_STATE_SAME_DB,
        ASR_STATE_NEXT_FAMILY,
        ASR_STATE_NEXT_NS,
        ASR_STATE_UDP_SEND,
        ASR_STATE_UDP_RECV,
        ASR_STATE_TCP_WRITE,
        ASR_STATE_TCP_READ,
        ASR_STATE_PACKET,
        ASR_STATE_SUBQUERY,
        ASR_STATE_NOT_FOUND,
        ASR_STATE_HALT,
};

#define MAXPACKETSZ     4096

__BEGIN_HIDDEN_DECLS

/* asr_utils.c */
void _asr_pack_init(struct asr_pack *, char *, size_t);
int _asr_pack_header(struct asr_pack *, const struct asr_dns_header *);
int _asr_pack_query(struct asr_pack *, uint16_t, uint16_t, const char *);
int _asr_pack_edns0(struct asr_pack *, uint16_t, int);
void _asr_unpack_init(struct asr_unpack *, const char *, size_t);
int _asr_unpack_header(struct asr_unpack *, struct asr_dns_header *);
int _asr_unpack_query(struct asr_unpack *, struct asr_dns_query *);
int _asr_unpack_rr(struct asr_unpack *, struct asr_dns_rr *);
int _asr_sockaddr_from_str(struct sockaddr *, int, const char *);
ssize_t _asr_dname_from_fqdn(const char *, char *, size_t);
ssize_t _asr_addr_as_fqdn(const char *, int, char *, size_t);
int hnok_lenient(const char *);
int _asr_is_localhost(const char*);

/* asr.c */
void _asr_resolver_done(void *);
struct asr_ctx *_asr_use_resolver(void *);
struct asr_ctx *_asr_no_resolver(void);
void _asr_ctx_unref(struct asr_ctx *);
struct asr_query *_asr_async_new(struct asr_ctx *, int);
void _asr_async_free(struct asr_query *);
size_t _asr_make_fqdn(const char *, const char *, char *, size_t);
char *_asr_strdname(const char *, char *, size_t);
int _asr_iter_db(struct asr_query *);
int _asr_parse_namedb_line(FILE *, char **, int, char *, size_t);

/* *_async.c */
struct asr_query *_res_query_async_ctx(const char *, int, int, struct asr_ctx *);
struct asr_query *_res_search_async_ctx(const char *, int, int, struct asr_ctx *);
struct asr_query *_gethostbyaddr_async_ctx(const void *, socklen_t, int,
    struct asr_ctx *);

int _asr_iter_domain(struct asr_query *, const char *, char *, size_t);

#ifdef DEBUG

#define DPRINT(...)             do { if(_asr_debug) {           \
                fprintf(_asr_debug, __VA_ARGS__);               \
        } } while (0)
#define DPRINT_PACKET(n, p, s)  do { if(_asr_debug) {           \
                fprintf(_asr_debug, "----- %s -----\n", n);     \
                _asr_dump_packet(_asr_debug, (p), (s));         \
                fprintf(_asr_debug, "--------------\n");                \
        } } while (0)

#else /* DEBUG */

#define DPRINT(...)
#define DPRINT_PACKET(...)

#endif /* DEBUG */

const char *_asr_querystr(int);
const char *_asr_statestr(int);
const char *_asr_transitionstr(int);
const char *_asr_print_sockaddr(const struct sockaddr *, char *, size_t);
void _asr_dump_config(FILE *, struct asr *);
void _asr_dump_packet(FILE *, const void *, size_t);

extern FILE *_asr_debug;

#define async_set_state(a, s) do {              \
        DPRINT("asr: [%s@%p] %s -> %s\n",       \
                _asr_querystr((a)->as_type),    \
                as,                             \
                _asr_statestr((a)->as_state),   \
                _asr_statestr((s)));            \
        (a)->as_state = (s); } while (0)

__END_HIDDEN_DECLS