/* This file is part of GNUnet. Copyright (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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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. */ struct GNUNET_SCHEDULER_Task * 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 = NULL; 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 @a 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 @a 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) { /* local-only request, with no result, clean up. */ if (NULL == cr->kill_task) cr->kill_task = GNUNET_SCHEDULER_add_now (&client_request_destroy, cr); 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 (NULL == 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 @a buf * @param buf where the callee should write the message * @return number of bytes written to @a 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 (NULL != 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 */