/*
 * Copyright (C) 2000  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.
 */

#ifndef LWD_CLIENT_H
#define LWD_CLIENT_H 1

#include <isc/event.h>
#include <isc/eventclass.h>
#include <isc/netaddr.h>
#include <isc/sockaddr.h>
#include <isc/types.h>

#include <dns/fixedname.h>
#include <dns/types.h>

#include <lwres/lwres.h>

#define LWRD_EVENTCLASS		ISC_EVENTCLASS(4242)

#define LWRD_SHUTDOWN		(LWRD_EVENTCLASS + 0x0001)

typedef struct client_s client_t;
typedef struct clientmgr_s clientmgr_t;

struct client_s {
	isc_sockaddr_t		address;	/* where to reply */
	clientmgr_t	       *clientmgr;	/* our parent */
	ISC_LINK(client_t)	link;
	unsigned int		state;
	void		       *arg;		/* packet processing state */

	/*
	 * Received data info.
	 */
	unsigned char		buffer[LWRES_RECVLENGTH]; /* receive buffer */
	isc_uint32_t		recvlength;	/* length recv'd */
	lwres_lwpacket_t	pkt;

	/*
	 * Send data state.  If sendbuf != buffer (that is, the send buffer
	 * isn't our receive buffer) it will be freed to the lwres_context_t.
	 */
	unsigned char	       *sendbuf;
	isc_uint32_t		sendlength;
	isc_buffer_t		recv_buffer;

	/*
	 * gabn (get address by name) state info.
	 */
	dns_adbfind_t		*find;
	dns_adbfind_t		*v4find;
	dns_adbfind_t		*v6find;
	unsigned int		find_wanted;	/* Addresses we want */
	dns_fixedname_t		target_name;
	lwres_gabnresponse_t	gabn;

	/*
	 * gnba (get name by address) state info.
	 */
	lwres_gnbaresponse_t	gnba;
	dns_byaddr_t	       *byaddr;
	unsigned int		options;
	isc_netaddr_t		na;
	dns_adbaddrinfo_t      *addrinfo;

	/*
	 * Alias and address info.  This is copied up to the gabn/gnba
	 * structures eventually.
	 *
	 * XXXMLG We can keep all of this in a client since we only service
	 * three packet types right now.  If we started handling more,
	 * we'd need to use "arg" above and allocate/destroy things.
	 */
	char		       *aliases[LWRES_MAX_ALIASES];
	isc_uint16_t		aliaslen[LWRES_MAX_ALIASES];
	lwres_addr_t		addrs[LWRES_MAX_ADDRS];
};

/*
 * Client states.
 *
 * _IDLE	The client is not doing anything at all.
 *
 * _RECV	The client is waiting for data after issuing a socket recv().
 *
 * _RECVDONE	Data has been received, and is being processed.
 *
 * _FINDWAIT	An adb (or other) request was made that cannot be satisfied
 *		immediately.  An event will wake the client up.
 *
 * _SEND	All data for a response has completed, and a reply was
 *		sent via a socket send() call.
 *
 * Badly formatted state table:
 *
 *	IDLE -> RECV when client has a recv() queued.
 *
 *	RECV -> RECVDONE when recvdone event received.
 *
 *	RECVDONE -> SEND if the data for a reply is at hand.
 *	RECVDONE -> FINDWAIT if more searching is needed, and events will
 *		eventually wake us up again.
 *
 *	FINDWAIT -> SEND when enough data was received to reply.
 *
 *	SEND -> IDLE when a senddone event was received.
 *
 *	At any time -> IDLE on error.  Sometimes this will be -> SEND
 *	instead, if enough data is on hand to reply with a meaningful
 *	error.
 *
 *	Packets which are badly formatted may or may not get error returns.
 */
#define CLIENT_STATE_IDLE		1
#define CLIENT_STATE_RECV		2
#define CLIENT_STATE_RECVDONE		3
#define CLIENT_STATE_FINDWAIT		4
#define CLIENT_STATE_SEND		5
#define CLIENT_STATE_SENDDONE		6

#define CLIENT_ISIDLE(c)	((c)->state == CLIENT_STATE_IDLE)
#define CLIENT_ISRECV(c)	((c)->state == CLIENT_STATE_RECV)
#define CLIENT_ISRECVDONE(c)	((c)->state == CLIENT_STATE_RECVDONE)
#define CLIENT_ISFINDWAIT(c)	((c)->state == CLIENT_STATE_FINDWAIT)
#define CLIENT_ISSEND(c)	((c)->state == CLIENT_STATE_SEND)

/*
 * Overall magic test that means we're not idle.
 */
#define CLIENT_ISRUNNING(c)	(!CLIENT_ISIDLE(c))

#define CLIENT_SETIDLE(c)	((c)->state = CLIENT_STATE_IDLE)
#define CLIENT_SETRECV(c)	((c)->state = CLIENT_STATE_RECV)
#define CLIENT_SETRECVDONE(c)	((c)->state = CLIENT_STATE_RECVDONE)
#define CLIENT_SETFINDWAIT(c)	((c)->state = CLIENT_STATE_FINDWAIT)
#define CLIENT_SETSEND(c)	((c)->state = CLIENT_STATE_SEND)
#define CLIENT_SETSENDDONE(c)	((c)->state = CLIENT_STATE_SENDDONE)

struct clientmgr_s {
	isc_mem_t	       *mctx;
	isc_task_t	       *task;		/* owning task */
	isc_socket_t	       *sock;		/* socket to use */
	dns_view_t	       *view;
	unsigned int		flags;
	isc_event_t		sdev;		/* shutdown event */
	lwres_context_t	       *lwctx;		/* lightweight proto context */
	ISC_LIST(client_t)	idle;		/* idle client slots */
	ISC_LIST(client_t)	running;	/* running clients */
};

#define CLIENTMGR_FLAG_RECVPENDING		0x00000001
#define CLIENTMGR_FLAG_SHUTTINGDOWN		0x00000002

void client_initialize(client_t *, clientmgr_t *);
isc_result_t client_start_recv(clientmgr_t *);
void client_state_idle(client_t *);

void client_recv(isc_task_t *, isc_event_t *);
void client_shutdown(isc_task_t *, isc_event_t *);
void client_send(isc_task_t *, isc_event_t *);

/*
 * Processing functions of various types.
 */
void process_gabn(client_t *, lwres_buffer_t *);
void process_gnba(client_t *, lwres_buffer_t *);
void process_noop(client_t *, lwres_buffer_t *);

void error_pkt_send(client_t *, isc_uint32_t);

void client_init_aliases(client_t *);
void client_init_gabn(client_t *);
void client_init_gnba(client_t *);

void DP(int level, const char *format, ...);
void hexdump(char *msg, void *base, size_t len);

#endif /* LWD_CLIENT_H */