/* Find public key in DNS
 * Copyright (C) 2000-2002  D. Hugh Redelmeier.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 */

#include <utils/identification.h>

extern int adns_qfd;   /* file descriptor for sending queries to adns */
extern int adns_afd;   /* file descriptor for receiving answers from adns */
extern const char *pluto_adns_option;   /* path from --pluto_adns */
extern void init_adns(void);
extern void stop_adns(void);
extern void handle_adns_answer(void);

extern bool unsent_ADNS_queries;
extern void send_unsent_ADNS_queries(void);

/* (common prefix of) stuff remembered between async query and answer.
 * Filled in by start_adns_query.
 * Freed by call to release_adns_continuation.
 */

struct adns_continuation;       /* forward declaration (not far!) */

typedef void (*cont_fn_t)(struct adns_continuation *cr, err_t ugh);

struct adns_continuation {
	unsigned long qtid;    /* query transaction id number */
	int type;              /* T_TXT or T_KEY, selecting rr type of interest */
	cont_fn_t cont_fn;     /* function to carry on suspended work */
	identification_t *id;  /* subject of query */
	bool sgw_specified;
	identification_t *sgw_id; /* peer, if constrained */
	lset_t debugging;      /* only used #ifdef DEBUG, but don't want layout to change */
	struct gw_info *gateways_from_dns;  /* answer, if looking for our TXT rrs */
#ifdef USE_KEYRR
	struct pubkey_list *keys_from_dns;  /* answer, if looking for KEY rrs */
#endif
	struct adns_continuation *previous, *next;
	struct pubkey *last_info;  /* the last structure we accumulated */
#ifdef USE_LWRES
	bool used;             /* have we called the cont_fn yet? */
	struct {
		u_char name_buf[NS_MAXDNAME + 2];
	} query;
#else /* ! USE_LWRES */
	struct adns_query query;
#endif /* ! USE_LWRES */
};

extern err_t start_adns_query(identification_t *id       /* domain to query */
	, identification_t *sgw_id   /* if non-null, any accepted gw_info must match */
	, int type  /* T_TXT or T_KEY, selecting rr type of interest */
	, cont_fn_t cont_fn /* continuation function */
	, struct adns_continuation *cr);


/* Gateway info gleaned from reverse DNS of client */
struct gw_info {
	unsigned refcnt;             /* reference counted! */
	unsigned pref;               /* preference: lower is better */
#define NO_TIME ((time_t) -2)    /* time_t value meaning "not_yet" */
	identification_t* client_id; /* id of client of peer */
	identification_t* gw_id;     /* id of peer (if id_is_ipaddr, .ip_addr is address) */
	bool gw_key_present;
	struct pubkey *key;
	struct gw_info *next;
};

extern void gw_addref(struct gw_info *gw);
extern void gw_delref(struct gw_info **gwp);
extern void reset_adns_restart_count(void);