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/*

 * Copyright (C) 2006 Ondrej Palkovsky

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - 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.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * 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.

 */

#ifndef __IPC_H__

#define __IPC_H__

/* Length of data being transfered with IPC call */

/* - the uspace may not be able to utilize full length */

#define IPC_CALL_LEN    4

/** Maximum active async calls per thread */

#define IPC_MAX_ASYNC_CALLS  4

/* Flags for calls */

#define IPC_CALL_ANSWERED      0x1 /**< This is answer to a call */

#define IPC_CALL_STATIC_ALLOC  0x2 /**< This call will not be freed on error */

#define IPC_CALL_DISPATCHED    0x4 /**< Call is in dispatch queue */

/* Flags for ipc_wait_for_call */

#define IPC_WAIT_NONBLOCKING   1

/* Flags of callid */

#define IPC_CALLID_ANSWERED  1

/* Return values from IPC_ASYNC */

#define IPC_CALLRET_FATAL         -1

#define IPC_CALLRET_TEMPORARY     -2

/* Macros for manipulating calling data */

#define IPC_SET_RETVAL(data, retval)   ((data)[0] = (retval))

#define IPC_SET_METHOD(data, val)   ((data)[0] = (val))

#define IPC_SET_ARG1(data, val)   ((data)[1] = (val))

#define IPC_SET_ARG2(data, val)   ((data)[2] = (val))

#define IPC_SET_ARG3(data, val)   ((data)[3] = (val))

#define IPC_GET_METHOD(data)           ((data)[0])

#define IPC_GET_RETVAL(data)           ((data)[0])

#define IPC_GET_ARG1(data)              ((data)[1])

#define IPC_GET_ARG2(data)              ((data)[2])

#define IPC_GET_ARG3(data)              ((data)[3])

/* Well known phone descriptors */

#define PHONE_NS              0

/* System-specific methods - only through special syscalls

 * These methods have special behaviour

 */

/** Protocol for CONNECT - TO - ME 

 *

 * Calling process asks the callee to create a callback connection,

 * so that it can start initiating new messages.

 *

 * The protocol for negotiating is:

 * - sys_connecttome - sends a message IPC_M_CONNECTTOME

 * - sys_wait_for_call - upon receipt tries to allocate new phone

 *                       - if it fails, responds with ELIMIT

 *                     - passes call to userspace. If userspace

 *                       responds with error, phone is deallocated and

 *                       error is sent back to caller. Otherwise 

 *                       the call is accepted and the response is sent back.

 *                     - the allocated phoneid is passed to userspace 

 *                       (on the receiving sid) as ARG3 of the call.

 *                     - the caller obtains taskid of the called thread

 */

#define IPC_M_CONNECTTOME     1

/** Protocol for CONNECT - ME - TO

 *

 * Calling process asks the callee to create for him a new connection.

 * E.g. the caller wants a name server to connect him to print server.

 *

 * The protocol for negotiating is:

 * - sys_connect_me_to - send a synchronous message to name server

 *                       indicating that it wants to be connected to some

 *                       service

 *   recepient         -  if ipc_answer == 0, then accept connection

 *                     -  otherwise connection refused

 *                     -  recepient may forward message. Forwarding

 *                        system message 

 *

 */

#define IPC_M_CONNECTMETO     2

/* Control messages that the server sends to the processes 

 * about their connections.

 */

/* Well-known methods */

#define IPC_M_LAST_SYSTEM     511

#define IPC_M_PING            512

/* User methods */

#define FIRST_USER_METHOD     1024

#ifdef KERNEL

#include <synch/mutex.h>

#include <synch/condvar.h>

#include <adt/list.h>

#define IPC_MAX_PHONES  16

typedef struct answerbox answerbox_t;

typedef __native ipc_data_t[IPC_CALL_LEN];

typedef struct {

	link_t list;

	answerbox_t *callerbox;

	int flags;

	task_t *sender;

	ipc_data_t data;

} call_t;

struct answerbox {

	SPINLOCK_DECLARE(lock);

	task_t *task;

	waitq_t wq;

	link_t connected_phones; /**< Phones connected to this answerbox */

	link_t calls;            /**< Received calls */

	link_t dispatched_calls; /* Should be hash table in the future */

	link_t answers;          /**< Answered calls */

};

typedef struct {

	SPINLOCK_DECLARE(lock);

	link_t list;

	answerbox_t *callee;

	int busy;

} phone_t;

extern void ipc_init(void);

extern call_t * ipc_wait_for_call(answerbox_t *box, int flags);

extern void ipc_answer(answerbox_t *box, call_t *request);

extern void ipc_call(phone_t *phone, call_t *request);

extern void ipc_call_sync(phone_t *phone, call_t *request);

extern void ipc_phone_destroy(phone_t *phone);

extern void ipc_phone_init(phone_t *phone);

extern void ipc_phone_connect(phone_t *phone, answerbox_t *box);

extern void ipc_call_free(call_t *call);

extern call_t * ipc_call_alloc(void);

extern void ipc_answerbox_init(answerbox_t *box);

extern void ipc_call_init(call_t *call);

extern void ipc_forward(call_t *call, answerbox_t *newbox,answerbox_t *oldbox);

extern answerbox_t *ipc_phone_0;

#endif

#endif