1 // -----------------------------------------------------------------------
2 // Copyright (C) 2006 - 2008 FRESCOR consortium partners:
4 // Universidad de Cantabria, SPAIN
5 // University of York, UK
6 // Scuola Superiore Sant'Anna, ITALY
7 // Kaiserslautern University, GERMANY
8 // Univ. Politécnica Valencia, SPAIN
9 // Czech Technical University in Prague, CZECH REPUBLIC
11 // Thales Communication S.A. FRANCE
12 // Visual Tools S.A. SPAIN
13 // Rapita Systems Ltd UK
16 // See http://www.frescor.org for a link to partners' websites
18 // FRESCOR project (FP6/2005/IST/5-034026) is funded
19 // in part by the European Union Sixth Framework Programme
20 // The European Union is not liable of any use that may be
24 // based on previous work (FSF) done in the FIRST project
26 // Copyright (C) 2005 Mälardalen University, SWEDEN
27 // Scuola Superiore S.Anna, ITALY
28 // Universidad de Cantabria, SPAIN
29 // University of York, UK
31 // FSF API web pages: http://marte.unican.es/fsf/docs
32 // http://shark.sssup.it/contrib/first/docs/
34 // This file is part of FRSH (FRescor ScHeduler)
36 // FRSH is free software; you can redistribute it and/or modify it
37 // under terms of the GNU General Public License as published by the
38 // Free Software Foundation; either version 2, or (at your option) any
39 // later version. FRSH is distributed in the hope that it will be
40 // useful, but WITHOUT ANY WARRANTY; without even the implied warranty
41 // of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
42 // General Public License for more details. You should have received a
43 // copy of the GNU General Public License along with FRSH; see file
44 // COPYING. If not, write to the Free Software Foundation, 675 Mass Ave,
45 // Cambridge, MA 02139, USA.
47 // As a special exception, including FRSH header files in a file,
48 // instantiating FRSH generics or templates, or linking other files
49 // with FRSH objects to produce an executable application, does not
50 // by itself cause the resulting executable application to be covered
51 // by the GNU General Public License. This exception does not
52 // however invalidate any other reasons why the executable file might be
53 // covered by the GNU Public License.
54 // -----------------------------------------------------------------------
56 //==============================================
57 // ******** ******* ******** ** **
58 // **///// /**////** **////// /** /**
59 // ** /** /** /** /** /**
60 // ******* /******* /********* /**********
61 // **//// /**///** ////////** /**//////**
62 // ** /** //** /** /** /**
63 // ** /** //** ******** /** /**
64 // // // // //////// // //
66 // FRSH(FRescor ScHeduler), pronounced "fresh"
67 //==============================================
68 #ifndef _FRSH_DISTRIBUTED_H_
69 #define _FRSH_DISTRIBUTED_H_
73 * @file frsh_distributed.h
77 #include "frsh_distributed_types.h"
78 #include "frsh_core_types.h"
82 // this global variable is assigned by frsh_distributed_init()
83 extern frsh_resource_id_t THE_FRSH_CPU_ID;
86 FRSH_NETPF_FRESCAN = 0,
93 * @defgroup distributed Distributed module
95 * This module defines the functions and typedefs for use in
96 * distributed applications.
98 * Each network is identified by its resource_id and FRSH hides its
99 * characteristics completely. The type of network is implied with
100 * its ID via a configuration table defined at compile time.
102 * FRSH uses the "message" as the atomic unit for every exchange.
103 * Queue sizes are measured in number of pending messages.
105 * FRSH provides a function to calculate the transmision time needed
106 * for a certain message size in a network as well as the maximum
107 * message size that can admit.
109 * Note also that package delivery guarantee is protocol dependent.
110 * For protocols in which the order is no guaranteed, the application
111 * needs to add extra info to detect possible package disorder.
113 * Summary of typical steps.
115 * 1. Map (internally in FRSH implementation)
116 * - node--> network_addresses
117 * - network --> resource_id's
118 * - unidirectional communication channel --> stream_id
119 * - other config --> protocol_info.
121 * 2. In a sending node:
122 * 2.1. Negotiates a "network contract" per communication channel
123 * that is used in the application. In the contract it is
125 * - frsh_resource_type = FRSH_RT_NETWORK.
126 * - frsh_resource_id = <network id #>
127 * - budget: Time needed to send the required data per period.
128 * (you can use frsh_netinfo_*() functions for this).
129 * - period: Period of sendings.
130 * - Queueing info: How will sends be queued at sendEndpoint.
131 * - Other protocol dependent function in protocol_contract_info.
132 * 2.2. Create a send_endpoint per any unidirectional stream that will
134 * resource_id --> the network through which the stream will
135 * flow (this is extra info needed for coherency
137 * destinator --> network_address of the destination.
138 * stream_id --> the unidirectional communication channel.
139 * 2.3. Bind the send_endpoint to the network contract negotiated
141 * 2.4. The (processor) sending vres invokes frsh_send_(a)sync() to
142 * send the data through the corresponding stream.
144 * 3. In a receiving node:
145 * 3.1. Create a receive_endpoint per any unidirectional stream
146 * that will be used in receiving.
147 * 3.2. The processor expecting a reception of message invokes
148 * frsh_receive_(a)sync() to read the incoming data.
150 * 4. When all comunication is finished and the channel is no longer
151 * needed the nodes will destroy the send and receive endpoints
152 * and the network contract will be canceled.
156 * frsh_distributed_init(void)
158 * This operation initializes all the installed networks and the structures
159 * that are necessary for the distributed module. Currently it is called by
160 * frsh_init so it is not necessary that the user calls it again.
163 * FRSH_ERR_INTERNAL_ERROR: protocol dependent internal errors \n
166 int frsh_distributed_init(void);
168 //////////////////////////////////////////////////////////////////////
170 //////////////////////////////////////////////////////////////////////
173 * @defgroup distcontract Contract Info for Distributed Systems
174 * @ingroup distributed
176 * These functions help you calculate the needed budget for network
177 * contracts and also to include protocol dependent info in contract
184 * frsh_network_get_max_message_size()
186 * This operation gives the maximum number of bytes that can be sent
187 * at a time through the send function when using the network designated by
188 * 'resource_id' and sending it to 'destination'.
190 * If the application needs to send bigger messages it will have to
193 * Some protocols, like IP, are capable of sending large messages
194 * (and use fragmentation internally) but other protocols don't.
196 * @param[in] resource_id The network we want the tx time from.
197 * @param[in] destination The destination address
198 * @param[out] max_size The maximum number of bytes for each message
202 * FRSH_ERR_INTERNAL_ERROR: protocol dependent internal errors \n
203 * FRSH_ERR_NOT_INITIALIZED: if the protocol is not initialized \n
204 * FRSH_ERR_RESOURCE_ID_INVALID: if resource id does not represent
205 * a network accessible from the current processing node \n
206 * FRSH_ERR_BAD_ARGUMENT: if pointers are NULL or destination is
210 int frsh_network_get_max_message_size
211 (const frsh_resource_id_t resource_id,
212 const frsh_network_address_t destination,
216 * frsh_network_bytes_to_budget()
218 * This operation converts a number of bytes into a temporal budget for
219 * a specific network. Network overheads are not included here but are
220 * considered internally when negotiating a specific contract.
222 * @param[in] resource_id The network
223 * @param[in] nbytes Number of bytes
224 * @param[out] budget The network budget for nbytes
228 * FRSH_ERR_INTERNAL_ERROR: protocol dependent internal errors \n
229 * FRSH_ERR_NOT_INITIALIZED: if the protocol is not initialized \n
230 * FRSH_ERR_RESOURCE_ID_INVALID: if resource id does not represent
231 * a network accessible from the current processing node \n
232 * FRSH_ERR_BAD_ARGUMENT: if pointers are NULL or nbytes is less
236 int frsh_network_bytes_to_budget
237 (const frsh_resource_id_t resource_id,
239 frsh_rel_time_t *budget);
242 * frsh_network_budget_to_bytes()
244 * This operation converts a temporal budget into a number of bytes for
245 * a specific network. Network overheads are not included.
247 * @param[in] resource_id The network
248 * @param[in] budget The network budget for nbytes
249 * @param[out] nbytes Number of bytes
253 * FRSH_ERR_INTERNAL_ERROR: protocol dependent internal errors \n
254 * FRSH_ERR_NOT_INITIALIZED: if the protocol is not initialized \n
255 * FRSH_ERR_RESOURCE_ID_INVALID: if resource id does not represent
256 * a network accessible from the current processing node \n
257 * FRSH_ERR_BAD_ARGUMENT: if pointers are NULL or budget refers to
258 * an invalid time value \n
261 int frsh_network_budget_to_bytes
262 (const frsh_resource_id_t resource_id,
263 const frsh_rel_time_t *budget,
267 * frsh_network_get_min_effective_budget()
269 * This operation gets the minimum effective budget for a network. Each message
270 * consumes a contracted budget in "chunks" (i.e: packets) that we call
271 * minimum effective budget.
273 * A negotiated contract, for N bytes in a period T, means that there is a
274 * virtual resource that reserves for the user:
276 * Ceiling ((N bytes) / budget_to_bytes (min_effective_budget)) "CHUNKS"
278 * Note that if the user decides not to send these N bytes at once but, say,
279 * one byte at a time, it will consume one "CHUNK" at a time and the reserved
280 * budget will become exhausted before sending all the bytes.
282 * @param[in] resource_id The network
283 * @param[out] budget The network budget
287 * FRSH_ERR_INTERNAL_ERROR: protocol dependent internal errors \n
288 * FRSH_ERR_NOT_INITIALIZED: if the protocol is not initialized \n
289 * FRSH_ERR_RESOURCE_ID_INVALID: if resource id does not represent
290 * a network accessible from the current processing node \n
291 * FRSH_ERR_BAD_ARGUMENT: if pointers are NULL \n
294 int frsh_network_get_min_effective_budget
295 (const frsh_resource_id_t resource_id,
296 frsh_rel_time_t *budget);
299 * frsh_contract_set_queueing_info()
301 * This function adds queueing parameters that will be used in the
302 * sendEndpoint when the sendEndpoint is bound to the vres.
304 int frsh_contract_set_queueing_info(frsh_endpoint_queueing_info_t queueing_info,
305 frsh_contract_t *contract);
308 * frsh_contract_get_queueing_info()
310 * This function gets the queueing parameters that were specified in
311 * the network contract.
313 int frsh_contract_get_queueing_info(const frsh_contract_t *contract,
314 frsh_endpoint_queueing_info_t *queueing_info);
317 * frsh_contract_set_protocol_info
319 * We add protocol info to the contract
321 int frsh_contract_set_protocol_info(frsh_protocol_info_t protocol_info,
322 frsh_contract_t *contract);
325 * frsh_contract_get_protocol_info
327 * We get protocol info from the contract
329 int frsh_contract_get_protocol_info(frsh_contract_t *contract,
330 frsh_protocol_info_t *protocol_info);
333 * frsh_contract_marshal
335 * Convert a contract to a sequence of bytes of minimum size so it can
336 * be sent through the network with the minimum amount of bytes.
340 int frsh_contract_marshal(const frsh_contract_t *contract,
341 unsigned char *buffer,
342 const size_t buffer_size,
346 * frsh_contract_unmarshal
348 * Convert a sequence of bytes generated by frsh_contract_marshal to a contract
352 int frsh_contract_unmarshal(frsh_contract_t *contract,
353 const unsigned char *marshal_bytes,
357 //////////////////////////////////////////////////////////////////////
358 // TWO STEP NEGOTIATION
359 //////////////////////////////////////////////////////////////////////
362 * @defgroup twostepnego Two Step Negotiation
363 * @ingroup distributed
365 * Using the core services of FRSH, contracts may be negotiated in a
368 * An alternative two-step negotiation process is introduced in the
369 * distribution module: the first step involves the reservation of the
370 * resources, but without the right to use them, and the second step
371 * is the commitment to use those resources.
373 * The rationale behind this approach is that in distributed systems,
374 * when a distributed transaction is being negotiated the system
375 * should only commit the virtual resources that were negotiated with
376 * various nodes in the system if the results of all negotiations
377 * match together. This approach enhances the efficiency since the
378 * actual temporal values of the virtual resources on distributed
379 * nodes are only changed if the initiator of the distributed
380 * transaction is satisfied with the results of the negotiations.
382 * After the reservation, it is not necessary to change the actual
383 * virtual resource attributes (and modifying the schedule) on each
384 * node before the initiator of the distributed transaction knows the
385 * amount of available virtual resources. A renegotiation of a
386 * reserved virtual resource is possible, to harmonize for the
387 * available virtual resources in other parts of the system, before a
388 * final commitment is made.
395 * frsh_contract_negotiate_reservation()
397 * Negotiate a service contract, obtaining a virtual resource id that
398 * represents a reservation of resources, but without the right to use
399 * those resources until the reservation is committed via
400 * frsh_vres_commit_reservation. In particular, this virtual resource
401 * cannot be bound until committed, but renegotiations are allowed for
404 int frsh_contract_negotiate_reservation
405 (const frsh_contract_t *contract,
406 frsh_vres_id_t *vres);
409 * frsh_vres_commit_reservation()
411 * Commit the resources reserved for a virtual resource through a
412 * frsh_contract_negotiate_reservation operation. The effects of
413 * subsequent calls to frsh_contract_negotiate_reservation and
414 * frsh_vres_commit_reservation are equivalent to a single call to
415 * frsh_contract_negotiate.
417 int frsh_vres_commit_reservation
418 (const frsh_vres_id_t vres);
424 //////////////////////////////////////////////////////////////////////
425 // TRANSMISSION SERVICES
426 //////////////////////////////////////////////////////////////////////
429 * @defgroup txservices Transmission services
430 * @ingroup distributed
432 * These functions allow to create and manage endpoints for sending
433 * and receiving and to perform send and receive operations both
434 * synchronously (blocking) and asynchronously (non-blocking).
441 * frsh_send_endpoint_create()
443 * This operation creates a unidirectional stream input endpoint
444 * through which, after the corresponding binding, it is possible to
445 * send data to a unicast or multicast destination.
447 * @param[in] resource_id Identifier of the network referred in the
448 * network contract as a resource_id.
449 * @param[in] destination FRSH abstraction of the protocol address for the
451 * @param[in] stream_id Identifier of the communication channel between
452 * the nodes. Multiplexing is achieved by using
453 * different streams between the same nodes and the
455 * @param[in] queueing_info Queueing params of the endpoint (size and
457 * @param[in] protocol_info Optional protocol-dependent info.
458 * @param[out] endpoint Placeholder for the endpoint object.
460 int frsh_send_endpoint_create
461 (frsh_resource_id_t resource_id,
462 frsh_network_address_t destination,
463 frsh_stream_id_t stream_id,
464 frsh_send_endpoint_protocol_info_t protocol_info,
465 frsh_send_endpoint_t *endpoint);
468 * frsh_send_endpoint_get_params()
470 * This operation returns in the variables associated to the
471 * endpoint at creation time.
473 int frsh_send_endpoint_get_params
474 (const frsh_send_endpoint_t endpoint,
475 frsh_resource_id_t *resource_id,
476 frsh_network_address_t *destination,
477 frsh_stream_id_t *stream,
478 frsh_send_endpoint_protocol_info_t *protocol_info);
481 * frsh_send_endpoint_destroy()
483 * This operation eliminates any resources reserved for the referenced
484 * endpoint. Pending messages will be discarded and processor-vres
485 * waiting in a synchronous operation will be awoken with an error
488 int frsh_send_endpoint_destroy
489 (frsh_send_endpoint_t endpoint);
492 * frsh_send_endpoint_bind()
494 * This operation associates a send endpoint with a network vres,
495 * which means that messages sent through this endpoint will consume
496 * the vres's reserved bandwidth and its packets will be sent
497 * according to the contract established for that vres.
499 * If the endpoint is already bound to another vres, it is effectively
500 * unbound from it and bound to the specified one. However if a vres
501 * is already bound to another endpoint an error is returned.
503 * A consistency check is done in which the resource_id specified at
504 * endpoint creation must correspond to the resource_id of the vres
507 * @return 0 if successful \n
508 * FRSH_ERR_BAD_ARGUMENT if the endpoint or the vres are not
510 * FRSH_ERR_ALREADY_BOUND if the vres is already bound to some
511 * other send endpoint \n
512 * FRSH_ERR_WRONG_NETWORK if the vres network id is not the same
513 * as the one in the endpoint \n
515 int frsh_send_endpoint_bind
516 (frsh_vres_id_t vres,
517 frsh_send_endpoint_t endpoint);
520 * frsh_send_endpoint_unbind()
522 * This operation unbinds a send endpoint from a vres. Endpoints with
523 * no vres associated cannot be used to send data, and they stay in
524 * that state until they are either eliminated or bound again.
526 * @return 0 if successful \n
527 * FRSH_ERR_NOT_BOUND if the endpoint was not bound \n
529 int frsh_send_endpoint_unbind
530 (frsh_send_endpoint_t endpoint);
533 * frsh_send_endpoint_get_vres_id()
535 * This operation copies the id of the vres that is bound to the
536 * specified send endpoint into the variable pointed to by vres.
538 * @return 0 if successful \n
539 * FRSH_ERR_NOT_BOUND if the endpoint was not bound \n
540 * FRSH_ERR_BAD_ARGUMENT if the endpoint is not valid or vres
543 int frsh_send_endpoint_get_vres_id
544 (const frsh_send_endpoint_t endpoint,
545 frsh_vres_id_t *vres);
550 * This operation sends a message stored in msg and of length size
551 * through the given endpoint. The operation is non-blocking and
552 * returns immediately.
554 * An internal frsh service will schedule the sending of messages and
555 * implement the communications sporadic vres corresponding to the
556 * network vres bound to the given endpoint.
558 * @returns 0 if successful \n
559 * FRSH_ERR_BAD_ARGUMENT if endpoint is not valid \n
560 * FRSH_ERR_NOT_BOUND if endpoint is not bound to a valid vres \n
561 * FRSH_ERR_TOO_LARGE if the message is too large for the
562 * network protocol \n
563 * FRSH_ERR_BUFFER_FULL if the message has been discarded
564 * because the queue is full (and does not
565 * have the policy FRSH_QP_OLDEST \n
568 (const frsh_send_endpoint_t endpoint,
575 * Similar to previous function but now the sending vres gets blocked
576 * until the message is processed.
579 (const frsh_send_endpoint_t endpoint,
584 * frsh_send_endpoint_get_status()
586 * This function tells the number of messages still pending in the
587 * endpoint queue, whether the network is up or down with some
588 * optional information which is protocol_dependent.
590 int frsh_send_endpoint_get_status
591 (const frsh_send_endpoint_t endpoint,
592 int *number_pending_msg,
593 frsh_endpoint_network_status_t *network_status,
594 frsh_protocol_status_t *protocol_status);
597 * frsh_receive_endpoint_create()
599 * This operation creates a receive endpoint associated with a
600 * undirectional stream within a network interface of the node.
602 * Receiving endpoints are not bound to any network vres, this is
603 * because don't originate any traffic.
605 * Note that the protocol address is not needed for reception because
606 * it can be determined internally by FRSH based on the resource_id.
608 * Note also that messages may come from diferent originators.
610 * @param[in] resource_id Id of the network from which we listen.
611 * @param[in] stream_id Id of the stream within the network.
612 * @param[in] queueing_info Buffering information(queue size and
614 * @param[in] protocol_info Extra protocol info opaque for the
616 * @param[in] endpoin Placeholder for the endpoint object.
618 * @return 0 if successful \n
619 * FRSH_ERR_BAD_ARGUMENT if the stream or the network id are not
622 int frsh_receive_endpoint_create
623 (frsh_resource_id_t resource_id,
624 frsh_stream_id_t stream_id,
625 frsh_endpoint_queueing_info_t queueing_info,
626 frsh_receive_endpoint_protocol_info_t protocol_info,
627 frsh_receive_endpoint_t *endpoint);
630 * frsh_receive_endpoint_get_params()
632 * This operation returns in the variables associated to the
633 * endpoint at creation time.
635 int frsh_receive_endpoint_get_params
636 (const frsh_receive_endpoint_t endpoint,
637 frsh_resource_id_t *resource_id,
638 frsh_stream_id_t *stream,
639 frsh_endpoint_queueing_info_t *queueing_info,
640 frsh_receive_endpoint_protocol_info_t *protocol_info);
643 * frsh_receive_endpoint_destroy()
645 * This operation eliminates any resources reserved for the referenced
646 * endpoint. Pending messages will be discarded and processor-vres
647 * waiting in a synchronous operation will be awoken with an error
650 int frsh_receive_endpoint_destroy
651 (frsh_receive_endpoint_t endpoint);
655 * frsh_receive_sync()
657 * If there are no messages available in the specified receive endpoint
658 * this operation blocks the calling thread waiting for a message to be
661 * When a message is available, if its size is less than or
662 * equal to the buffer_size, the function stores it in the variable
663 * pointed to by buffer and puts the number of bytes received in the
664 * variable pointed to by message size.
666 * The function fails with FRSH_ERR_NO_SPACE if the buffersize is
667 * too small for the message received. In this case the message is
670 * Messages arriving at a destination buffer that is full will be
671 * silently discarded (details in the queueing policy of the
672 * endpoint). The application is responsible of reading the receive
673 * endpoints with appropriate regularity, or of using a sequence
674 * number or some other mechanism to detect any lost messages.
676 * @return 0 if successful \n
677 * FRSH_ERR_BAD_ARGUMENT if the endpoint is not valid, or if
678 * buffer or message_size are NULL.\n
679 * FRSH_ERR_NO_SPACE if the message size is bigger than the
682 int frsh_receive_sync
683 (const frsh_receive_endpoint_t endpoint,
686 size_t *message_size,
687 frsh_network_address_t *from);
690 * frsh_receive_async()
692 * This operation is similar to the previous one but it works in a non
693 * blocking (asynchronous) fashion. If no message is available it
694 * returns with error FRSH_NO_MESSAGE.
696 * @return 0 if successful \n
697 * FRSH_ERR_BAD_ARGUMENT if the endpoint is not valid, or if
698 * buffer or message_size are NULL \n
699 * FRSH_NO_MESSAGE if no messages are available in the queue \n
700 * FRSH_ERR_NO_SPACE if the message size is bigger than the
703 int frsh_receive_async
704 (const frsh_receive_endpoint_t endpoint,
707 size_t *message_size,
708 frsh_network_address_t *from);
712 * frsh_receive_endpoint_get_status
714 * This function tells the number of messages still pending in the
715 * endpoint queue, whether the network is up or down and some optional
716 * information which is protocol dependent.
718 int frsh_receive_endpoint_get_status
719 (const frsh_receive_endpoint_t endpoint,
720 int *number_pending_messages,
721 frsh_endpoint_network_status_t *network_status,
722 frsh_protocol_status_t *protocol_status);
728 #endif // _FRSH_DISTRIBUTED_H_