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- /*
- This file is part of GNUnet.
- (C) 2011 Christian Grothoff (and other contributing authors)
- GNUnet 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 3, or (at your
- option) any later version.
- GNUnet 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.
- You should have received a copy of the GNU General Public License
- along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
- */
- /**
- * @file fs/gnunet-service-fs_lc.c
- * @brief API to handle 'local clients'
- * @author Christian Grothoff
- */
- #include "platform.h"
- #include "gnunet-service-fs.h"
- #include "gnunet-service-fs_lc.h"
- #include "gnunet-service-fs_cp.h"
- #include "gnunet-service-fs_pr.h"
- /**
- * Doubly-linked list of requests we are performing
- * on behalf of the same client.
- */
- struct ClientRequest
- {
- /**
- * This is a doubly-linked list.
- */
- struct ClientRequest *next;
- /**
- * This is a doubly-linked list.
- */
- struct ClientRequest *prev;
- /**
- * Request this entry represents.
- */
- struct GSF_PendingRequest *pr;
- /**
- * Client list this request belongs to.
- */
- struct GSF_LocalClient *lc;
- /**
- * Task scheduled to destroy the request.
- */
- GNUNET_SCHEDULER_TaskIdentifier kill_task;
- };
- /**
- * Replies to be transmitted to the client. The actual
- * response message is allocated after this struct.
- */
- struct ClientResponse
- {
- /**
- * This is a doubly-linked list.
- */
- struct ClientResponse *next;
- /**
- * This is a doubly-linked list.
- */
- struct ClientResponse *prev;
- /**
- * Client list entry this response belongs to.
- */
- struct GSF_LocalClient *lc;
- /**
- * Number of bytes in the response.
- */
- size_t msize;
- };
- /**
- * A local client.
- */
- struct GSF_LocalClient
- {
- /**
- * We keep clients in a DLL.
- */
- struct GSF_LocalClient *next;
- /**
- * We keep clients in a DLL.
- */
- struct GSF_LocalClient *prev;
- /**
- * ID of the client.
- */
- struct GNUNET_SERVER_Client *client;
- /**
- * Head of list of requests performed on behalf
- * of this client right now.
- */
- struct ClientRequest *cr_head;
- /**
- * Tail of list of requests performed on behalf
- * of this client right now.
- */
- struct ClientRequest *cr_tail;
- /**
- * Head of linked list of responses.
- */
- struct ClientResponse *res_head;
- /**
- * Tail of linked list of responses.
- */
- struct ClientResponse *res_tail;
- /**
- * Context for sending replies.
- */
- struct GNUNET_SERVER_TransmitHandle *th;
- };
- /**
- * Head of linked list of our local clients.
- */
- static struct GSF_LocalClient *client_head;
- /**
- * Head of linked list of our local clients.
- */
- static struct GSF_LocalClient *client_tail;
- /**
- * Look up a local client record or create one if it
- * doesn't exist yet.
- *
- * @param client handle of the client
- * @return handle to local client entry
- */
- struct GSF_LocalClient *
- GSF_local_client_lookup_ (struct GNUNET_SERVER_Client *client)
- {
- struct GSF_LocalClient *pos;
- pos = client_head;
- while ((NULL != pos) && (pos->client != client))
- pos = pos->next;
- if (NULL != pos)
- return pos;
- pos = GNUNET_new (struct GSF_LocalClient);
- pos->client = client;
- GNUNET_CONTAINER_DLL_insert (client_head, client_tail, pos);
- return pos;
- }
- /**
- * Free the given client request.
- *
- * @param cls the client request to free
- * @param tc task context
- */
- static void
- client_request_destroy (void *cls,
- const struct GNUNET_SCHEDULER_TaskContext *tc)
- {
- struct ClientRequest *cr = cls;
- struct GSF_LocalClient *lc;
- cr->kill_task = GNUNET_SCHEDULER_NO_TASK;
- lc = cr->lc;
- GNUNET_CONTAINER_DLL_remove (lc->cr_head, lc->cr_tail, cr);
- GSF_pending_request_cancel_ (cr->pr, GNUNET_YES);
- GNUNET_STATISTICS_update (GSF_stats,
- gettext_noop ("# client searches active"), -1,
- GNUNET_NO);
- GNUNET_free (cr);
- }
- /**
- * Handle a reply to a pending request. Also called if a request
- * expires (then with data == NULL). The handler may be called
- * many times (depending on the request type), but will not be
- * called during or after a call to GSF_pending_request_cancel
- * and will also not be called anymore after a call signalling
- * expiration.
- *
- * @param cls user-specified closure
- * @param eval evaluation of the result
- * @param pr handle to the original pending request
- * @param reply_anonymity_level anonymity level for the reply, UINT32_MAX for "unknown"
- * @param expiration when does 'data' expire?
- * @param last_transmission when was the last time we've tried to download this block? (FOREVER if unknown)
- * @param type type of the block
- * @param data response data, NULL on request expiration
- * @param data_len number of bytes in data
- */
- static void
- client_response_handler (void *cls, enum GNUNET_BLOCK_EvaluationResult eval,
- struct GSF_PendingRequest *pr,
- uint32_t reply_anonymity_level,
- struct GNUNET_TIME_Absolute expiration,
- struct GNUNET_TIME_Absolute last_transmission,
- enum GNUNET_BLOCK_Type type, const void *data,
- size_t data_len)
- {
- struct ClientRequest *cr = cls;
- struct GSF_LocalClient *lc;
- struct ClientPutMessage *pm;
- const struct GSF_PendingRequestData *prd;
- size_t msize;
- if (NULL == data)
- {
- /* ugh, request 'timed out' -- how can this be? */
- GNUNET_break (0);
- return;
- }
- prd = GSF_pending_request_get_data_ (pr);
- GNUNET_break (type != GNUNET_BLOCK_TYPE_ANY);
- if ((prd->type != type) && (prd->type != GNUNET_BLOCK_TYPE_ANY))
- {
- GNUNET_break (0);
- return;
- }
- GNUNET_STATISTICS_update (GSF_stats,
- gettext_noop
- ("# replies received for local clients"), 1,
- GNUNET_NO);
- GNUNET_assert (pr == cr->pr);
- lc = cr->lc;
- msize = sizeof (struct ClientPutMessage) + data_len;
- {
- char buf[msize] GNUNET_ALIGN;
- pm = (struct ClientPutMessage *) buf;
- pm->header.type = htons (GNUNET_MESSAGE_TYPE_FS_PUT);
- pm->header.size = htons (msize);
- pm->type = htonl (type);
- pm->expiration = GNUNET_TIME_absolute_hton (expiration);
- pm->last_transmission = GNUNET_TIME_absolute_hton (last_transmission);
- pm->num_transmissions = htonl (prd->num_transmissions);
- pm->respect_offered = htonl (prd->respect_offered);
- memcpy (&pm[1], data, data_len);
- GSF_local_client_transmit_ (lc, &pm->header);
- }
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Queued reply to query `%s' for local client\n",
- GNUNET_h2s (&prd->query), (unsigned int) prd->type);
- if (GNUNET_BLOCK_EVALUATION_OK_LAST != eval)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Evaluation %d - keeping query alive\n",
- (int) eval);
- return;
- }
- if (GNUNET_SCHEDULER_NO_TASK == cr->kill_task)
- cr->kill_task = GNUNET_SCHEDULER_add_now (&client_request_destroy, cr);
- }
- /**
- * Handle START_SEARCH-message (search request from local client).
- * Only responsible for creating the request entry itself and setting
- * up reply callback and cancellation on client disconnect. Does NOT
- * execute the actual request strategy (planning).
- *
- * @param client identification of the client
- * @param message the actual message
- * @param prptr where to store the pending request handle for the request
- * @return #GNUNET_YES to start local processing,
- * #GNUNET_NO to not (yet) start local processing,
- * #GNUNET_SYSERR on error
- */
- int
- GSF_local_client_start_search_handler_ (struct GNUNET_SERVER_Client *client,
- const struct GNUNET_MessageHeader *message,
- struct GSF_PendingRequest **prptr)
- {
- static struct GNUNET_PeerIdentity all_zeros;
- const struct SearchMessage *sm;
- struct GSF_LocalClient *lc;
- struct ClientRequest *cr;
- struct GSF_PendingRequestData *prd;
- uint16_t msize;
- unsigned int sc;
- enum GNUNET_BLOCK_Type type;
- enum GSF_PendingRequestOptions options;
- msize = ntohs (message->size);
- if ((msize < sizeof (struct SearchMessage)) ||
- (0 != (msize - sizeof (struct SearchMessage)) % sizeof (struct GNUNET_HashCode)))
- {
- GNUNET_break (0);
- *prptr = NULL;
- return GNUNET_SYSERR;
- }
- GNUNET_STATISTICS_update (GSF_stats,
- gettext_noop ("# client searches received"), 1,
- GNUNET_NO);
- sc = (msize - sizeof (struct SearchMessage)) / sizeof (struct GNUNET_HashCode);
- sm = (const struct SearchMessage *) message;
- type = ntohl (sm->type);
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Received request for `%s' of type %u from local client\n",
- GNUNET_h2s (&sm->query), (unsigned int) type);
- lc = GSF_local_client_lookup_ (client);
- cr = NULL;
- /* detect duplicate UBLOCK requests */
- if ((type == GNUNET_BLOCK_TYPE_FS_UBLOCK) ||
- (type == GNUNET_BLOCK_TYPE_ANY))
- {
- cr = lc->cr_head;
- while (NULL != cr)
- {
- prd = GSF_pending_request_get_data_ (cr->pr);
- /* only unify with queries that hae not yet started local processing
- (SEARCH_MESSAGE_OPTION_CONTINUED was always set) and that have a
- matching query and type */
- if ((GNUNET_YES != prd->has_started) &&
- (0 != memcmp (&prd->query, &sm->query, sizeof (struct GNUNET_HashCode))) &&
- (prd->type == type))
- break;
- cr = cr->next;
- }
- }
- if (NULL != cr)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Have existing request, merging content-seen lists.\n");
- GSF_pending_request_update_ (cr->pr, (const struct GNUNET_HashCode *) &sm[1], sc);
- GNUNET_STATISTICS_update (GSF_stats,
- gettext_noop
- ("# client searches updated (merged content seen list)"),
- 1, GNUNET_NO);
- }
- else
- {
- GNUNET_STATISTICS_update (GSF_stats,
- gettext_noop ("# client searches active"), 1,
- GNUNET_NO);
- cr = GNUNET_new (struct ClientRequest);
- cr->lc = lc;
- GNUNET_CONTAINER_DLL_insert (lc->cr_head, lc->cr_tail, cr);
- options = GSF_PRO_LOCAL_REQUEST;
- if (0 != (SEARCH_MESSAGE_OPTION_LOOPBACK_ONLY & ntohl (sm->options)))
- options |= GSF_PRO_LOCAL_ONLY;
- cr->pr = GSF_pending_request_create_ (options, type,
- &sm->query,
- (0 !=
- memcmp (&sm->target, &all_zeros,
- sizeof (struct GNUNET_PeerIdentity)))
- ? &sm->target : NULL, NULL, 0,
- 0 /* bf */ ,
- ntohl (sm->anonymity_level),
- 0 /* priority */ ,
- 0 /* ttl */ ,
- 0 /* sender PID */ ,
- 0 /* origin PID */ ,
- (const struct GNUNET_HashCode *) &sm[1], sc,
- &client_response_handler, cr);
- }
- *prptr = cr->pr;
- return (0 !=
- (SEARCH_MESSAGE_OPTION_CONTINUED & ntohl (sm->options))) ? GNUNET_NO :
- GNUNET_YES;
- }
- /**
- * Transmit the given message by copying it to the target buffer
- * "buf". "buf" will be NULL and "size" zero if the socket was closed
- * for writing in the meantime. In that case, do nothing
- * (the disconnect or shutdown handler will take care of the rest).
- * If we were able to transmit messages and there are still more
- * pending, ask core again for further calls to this function.
- *
- * @param cls closure, pointer to the 'struct GSF_LocalClient'
- * @param size number of bytes available in buf
- * @param buf where the callee should write the message
- * @return number of bytes written to buf
- */
- static size_t
- transmit_to_client (void *cls, size_t size, void *buf)
- {
- struct GSF_LocalClient *lc = cls;
- char *cbuf = buf;
- struct ClientResponse *res;
- size_t msize;
- lc->th = NULL;
- if (NULL == buf)
- return 0;
- msize = 0;
- while ((NULL != (res = lc->res_head)) && (res->msize <= size))
- {
- memcpy (&cbuf[msize], &res[1], res->msize);
- msize += res->msize;
- size -= res->msize;
- GNUNET_CONTAINER_DLL_remove (lc->res_head, lc->res_tail, res);
- GNUNET_free (res);
- }
- if (NULL != res)
- lc->th =
- GNUNET_SERVER_notify_transmit_ready (lc->client, res->msize,
- GNUNET_TIME_UNIT_FOREVER_REL,
- &transmit_to_client, lc);
- return msize;
- }
- /**
- * Transmit a message to the given local client as soon as possible.
- * If the client disconnects before transmission, the message is
- * simply discarded.
- *
- * @param lc recipient
- * @param msg message to transmit to client
- */
- void
- GSF_local_client_transmit_ (struct GSF_LocalClient *lc,
- const struct GNUNET_MessageHeader *msg)
- {
- struct ClientResponse *res;
- size_t msize;
- msize = ntohs (msg->size);
- res = GNUNET_malloc (sizeof (struct ClientResponse) + msize);
- res->lc = lc;
- res->msize = msize;
- memcpy (&res[1], msg, msize);
- GNUNET_CONTAINER_DLL_insert_tail (lc->res_head, lc->res_tail, res);
- if (NULL == lc->th)
- lc->th =
- GNUNET_SERVER_notify_transmit_ready (lc->client, msize,
- GNUNET_TIME_UNIT_FOREVER_REL,
- &transmit_to_client, lc);
- }
- /**
- * A client disconnected from us. Tear down the local client
- * record.
- *
- * @param cls unused
- * @param client handle of the client
- */
- void
- GSF_client_disconnect_handler_ (void *cls, struct GNUNET_SERVER_Client *client)
- {
- struct GSF_LocalClient *pos;
- struct ClientRequest *cr;
- struct ClientResponse *res;
- pos = client_head;
- while ((pos != NULL) && (pos->client != client))
- pos = pos->next;
- if (NULL == pos)
- return;
- while (NULL != (cr = pos->cr_head))
- {
- if (GNUNET_SCHEDULER_NO_TASK != cr->kill_task)
- GNUNET_SCHEDULER_cancel (cr->kill_task);
- client_request_destroy (cr, NULL);
- }
- while (NULL != (res = pos->res_head))
- {
- GNUNET_CONTAINER_DLL_remove (pos->res_head, pos->res_tail, res);
- GNUNET_free (res);
- }
- if (NULL != pos->th)
- {
- GNUNET_SERVER_notify_transmit_ready_cancel (pos->th);
- pos->th = NULL;
- }
- GSF_handle_local_client_disconnect_ (pos);
- GNUNET_CONTAINER_DLL_remove (client_head, client_tail, pos);
- GNUNET_free (pos);
- }
- /* end of gnunet-service-fs_lc.c */
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