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Diffstat (limited to 'src/lockmanager/gnunet-service-lockmanager.c')
| -rw-r--r-- | src/lockmanager/gnunet-service-lockmanager.c | 899 |
1 files changed, 899 insertions, 0 deletions
diff --git a/src/lockmanager/gnunet-service-lockmanager.c b/src/lockmanager/gnunet-service-lockmanager.c new file mode 100644 index 0000000..8ec9889 --- /dev/null +++ b/src/lockmanager/gnunet-service-lockmanager.c @@ -0,0 +1,899 @@ +/* + This file is part of GNUnet. + (C) 2012 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 2, 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 lockmanager/gnunet-service-lockmanager.c + * @brief implementation of the LOCKMANAGER service + * @author Sree Harsha Totakura + */ + +#include "platform.h" +#include "gnunet_common.h" +#include "gnunet_container_lib.h" +#include "gnunet_protocols.h" +#include "gnunet_service_lib.h" +#include "gnunet_server_lib.h" + +#include "lockmanager.h" + + +#define LOG(kind,...) \ + GNUNET_log (kind, __VA_ARGS__) + +#define TIME_REL_MINS(min) \ + GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, min) + +#define TIMEOUT TIME_REL_MINS(3) + + +/** + * Doubly linked list of clients having connections to us + */ +struct ClientList; + + +/** + * Doubly linked list of clients waiting for a lock + */ +struct WaitList +{ + /** + * The next client structure + */ + struct WaitList *next; + + /** + * The prev client structure + */ + struct WaitList *prev; + + /** + * Pointer to the client + */ + struct ClientList *cl_entry; +}; + + +/** + * Structure representing a Lock + */ +struct Lock +{ + /** + * List head of clients waiting for this lock + */ + struct WaitList *wl_head; + + /** + * List tail of clients waiting for this lock + */ + struct WaitList *wl_tail; + + /** + * The client which is currently holding this lock + */ + struct ClientList *cl_entry; + + /** + * The name of the locking domain this lock belongs to + */ + char *domain_name; + + /** + * The number of this lock + */ + uint32_t lock_num; +}; + + +/** + * A Lock element for a doubly linked list + */ +struct LockList +{ + /** + * The next element pointer + */ + struct LockList *next; + + /** + * Pointer to the previous element + */ + struct LockList *prev; + + /** + * Pointer to the Lock + */ + struct Lock *lock; +}; + + +/** + * Doubly linked list of clients having connections to us + */ +struct ClientList +{ + + /** + * The next client structure + */ + struct ClientList *next; + + /** + * The previous client structure + */ + struct ClientList *prev; + + /** + * Head of the doubly linked list of the currently held locks by this client + */ + struct LockList *ll_head; + + /** + * Tail of the doubly linked list of the currently held locks by this client + */ + struct LockList *ll_tail; + + /** + * Pointer to the client + */ + struct GNUNET_SERVER_Client *client; +}; + + +/** + * Structure for matching a lock + */ +struct LockMatch +{ + /** + * The matched LockingRequest entry; Should be NULL if no entry is found + */ + struct Lock *matched_entry; + + /** + * The locking domain name of the lock + */ + const char *domain_name; + + /** + * The lock number + */ + uint32_t lock_num; +}; + + +/** + * Map of lock-keys to the 'struct LockList' entry for the key. + */ +static struct GNUNET_CONTAINER_MultiHashMap *lock_map; + +/** + * Head of the doubly linked list of clients currently connected + */ +static struct ClientList *cl_head; + +/** + * Tail of the doubly linked list of clients currently connected + */ +static struct ClientList *cl_tail; + + +/** + * Get the key for the given lock in the 'lock_map'. + * + * @param domain_name + * @param lock_number + * @param key set to the key + */ +static void +get_key (const char *domain_name, + uint32_t lock_number, + struct GNUNET_HashCode *key) +{ + uint32_t *last_32; + + GNUNET_CRYPTO_hash (domain_name, + strlen (domain_name), + key); + last_32 = (uint32_t *) key; + *last_32 ^= lock_number; +} + + +/** + * Hashmap iterator for matching a lock + * + * @param cls the LockMatch structure + * @param key current key code + * @param value value in the hash map (struct Lock) + * @return GNUNET_YES if we should continue to + * iterate, + * GNUNET_NO if not. + */ +static int +match_iterator (void *cls, const GNUNET_HashCode *key, void *value) +{ + struct LockMatch *match = cls; + struct Lock *lock = value; + + if ( (match->lock_num == lock->lock_num) + && (0 == strcmp (match->domain_name, lock->domain_name)) ) + { + match->matched_entry = lock; + return GNUNET_NO; + } + return GNUNET_YES; +} + + +/** + * Function to search for a lock in the global lock hashmap + * + * @param domain_name the name of the locking domain + * @param lock_num the number of the lock + * @return the lock if found; NULL if not + */ +static struct Lock * +find_lock (const char *domain_name, + const uint32_t lock_num) + +{ + struct LockMatch match; + struct GNUNET_HashCode key; + + match.lock_num = lock_num; + match.domain_name = domain_name; + match.matched_entry = NULL; + get_key (domain_name, lock_num, &key); + GNUNET_CONTAINER_multihashmap_get_multiple (lock_map, + &key, + &match_iterator, + &match); + return match.matched_entry; +} + + +/** + * Adds a lock to the global lock hashmap + * + * @param domain_name the name of the lock's locking domain + * @param lock_num the lock number + * @return pointer to the lock structure which is added to lock map + */ +static struct Lock * +add_lock (const char *domain_name, + uint32_t lock_num) +{ + struct Lock *lock; + struct GNUNET_HashCode key; + size_t domain_name_len; + + lock = GNUNET_malloc (sizeof (struct Lock)); + domain_name_len = strlen (domain_name) + 1; + lock->domain_name = GNUNET_malloc (domain_name_len); + strncpy (lock->domain_name, domain_name, domain_name_len); + lock->lock_num = lock_num; + get_key (domain_name, lock_num, &key); + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Adding a lock with num: %d and domain: %s to the lock map\n", + lock->lock_num, lock->domain_name); + GNUNET_CONTAINER_multihashmap_put (lock_map, + &key, + lock, + GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE); + return lock; +} + + +/** + * Removes a lock from the lock map. The WaitList of the lock should be empty + * + * @param lock the lock to remove + */ +static void +remove_lock (struct Lock *lock) +{ + struct GNUNET_HashCode key; + + GNUNET_assert (NULL == lock->wl_head); + get_key (lock->domain_name, + lock->lock_num, + &key); + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Removing lock with num: %u, domain: %s from lock map\n", + lock->lock_num, lock->domain_name); + GNUNET_assert (GNUNET_YES == GNUNET_CONTAINER_multihashmap_remove + (lock_map, &key, lock)); + GNUNET_free (lock->domain_name); + GNUNET_free (lock); +} + + +/** + * Find the LockList entry corresponding to the given Lock in a ClientList + * entry + * + * @param cl_entry the ClientList entry whose lock list has to be searched + * @param lock the lock which has to be matched + * @return the matching LockList entry; NULL if no match is found + */ +static struct LockList * +cl_ll_find_lock (struct ClientList *cl_entry, + const struct Lock *lock) +{ + struct LockList *ll_entry; + + for (ll_entry = cl_entry->ll_head; + NULL != ll_entry; ll_entry = ll_entry->next) + { + if (lock == ll_entry->lock) + return ll_entry; + } + return NULL; +} + + +/** + * Function to append a lock to the lock list of a ClientList entry + * + * @param cl_entry the client which currently owns this lock + * @param lock the lock to be added to the cl_entry's lock list + */ +static void +cl_ll_add_lock (struct ClientList *cl_entry, + struct Lock *lock) +{ + struct LockList *ll_entry; + + ll_entry = GNUNET_malloc (sizeof (struct LockList)); + ll_entry->lock = lock; + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Adding a lock with num: %u and domain: %s to lock list\n", + lock->lock_num, lock->domain_name); + GNUNET_CONTAINER_DLL_insert_tail (cl_entry->ll_head, + cl_entry->ll_tail, + ll_entry); +} + + +/** + * Function to delete a lock from the lock list of the given ClientList entry + * + * @param cl_entry the ClientList entry + * @param ll_entry the LockList entry to be deleted + */ +static void +cl_ll_remove_lock (struct ClientList *cl_entry, + struct LockList *ll_entry) +{ + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Removing lock with num: %u, domain: %s from lock list of a client\n", + ll_entry->lock->lock_num, + ll_entry->lock->domain_name); + GNUNET_assert (NULL != cl_entry->ll_head); + GNUNET_CONTAINER_DLL_remove (cl_entry->ll_head, + cl_entry->ll_tail, + ll_entry); + GNUNET_free (ll_entry); +} + + +/** + * Find a WaitList entry in the waiting list of a lock + * + * @param lock the lock whose wait list has to be searched + * @param cl_entry the ClientList entry to be searched + * @return the WaitList entry matching the given cl_entry; NULL if not match + * was found + */ +static struct WaitList * +lock_wl_find (const struct Lock *lock, + const struct ClientList *cl_entry) +{ + struct WaitList *wl_entry; + + for (wl_entry = lock->wl_head; + NULL != wl_entry; + wl_entry = wl_entry->next) + { + if (cl_entry == wl_entry->cl_entry) + return wl_entry; + } + return NULL; +} + + +/** + * Add a client to the wait list of given lock + * + * @param lock the lock list entry of a lock + * @param cl_entry the client to queue for the lock's wait list + */ +static void +lock_wl_add_client (struct Lock *lock, + struct ClientList *cl_entry) +{ + struct WaitList *wl_entry; + + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Adding a client to lock's wait list (lock num: %u, domain: %s)\n", + lock->lock_num, + lock->domain_name); + wl_entry = GNUNET_malloc (sizeof (struct WaitList)); + wl_entry->cl_entry = cl_entry; + GNUNET_CONTAINER_DLL_insert_tail (lock->wl_head, + lock->wl_tail, + wl_entry); +} + + +/** + * Remove an entry from the wait list of the given lock + * + * @param lock the lock + * @param wl_entry the wait list entry to be removed + */ +static void +lock_wl_remove (struct Lock *lock, + struct WaitList *wl_entry) +{ + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Removing client from wait list of lock with num: %u, domain: %s\n", + lock->lock_num, lock->domain_name); + GNUNET_CONTAINER_DLL_remove (lock->wl_head, + lock->wl_tail, + wl_entry); + GNUNET_free (wl_entry); +} + + +/** + * Search for a client in the client list + * + * @param client the client to be searched for + * @return the ClientList entry; NULL if the client is not found + */ +static struct ClientList * +cl_find_client (const struct GNUNET_SERVER_Client *client) +{ + struct ClientList *current; + + for (current = cl_head; NULL != current; current = current->next) + if (client == current->client) + return current; + return NULL; +} + + +/** + * Append a client to the client list + * + * @param client the client to be appended to the list + * @return the client list entry which is added to the client list + */ +static struct ClientList * +cl_add_client (struct GNUNET_SERVER_Client *client) +{ + struct ClientList *new_client; + + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Adding a client to the client list\n"); + new_client = GNUNET_malloc (sizeof (struct ClientList)); + GNUNET_SERVER_client_keep (client); + new_client->client = client; + GNUNET_CONTAINER_DLL_insert_tail (cl_head, + cl_tail, + new_client); + return new_client; +} + + +/** + * Delete the given client from the client list. The LockList should be empty + * + * @param cl_entry the client list entry to delete + */ +static void +cl_remove_client (struct ClientList *cl_entry) +{ + GNUNET_assert (NULL == cl_entry->ll_head); + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Removing a client from the client list\n"); + GNUNET_SERVER_client_drop (cl_entry->client); + GNUNET_CONTAINER_DLL_remove (cl_head, + cl_tail, + cl_entry); + GNUNET_free (cl_entry); +} + + +/** + * Transmit notify for sending message to client + * + * @param cls the message to send + * @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_notify (void *cls, size_t size, void *buf) +{ + struct GNUNET_LOCKMANAGER_Message *msg = cls; + uint16_t msg_size; + + if ((0 == size) || (NULL == buf)) + { + /* FIXME: Timed out -- requeue? */ + return 0; + } + msg_size = ntohs (msg->header.size); + GNUNET_assert (size >= msg_size); + memcpy (buf, msg, msg_size); + GNUNET_free (msg); + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Message of size %u sent\n", msg_size); + return msg_size; +} + + +/** + * Send SUCCESS message to the client + * + * @param client the client to which the message has to be sent + * @param domain_name the locking domain of the successfully acquried lock + * @param lock_num the number of the successfully acquired lock + */ +static void +send_success_msg (struct GNUNET_SERVER_Client *client, + const char *domain_name, + int lock_num) +{ + struct GNUNET_LOCKMANAGER_Message *reply; + size_t domain_name_len; + uint16_t reply_size; + + domain_name_len = strlen (domain_name) + 1; + reply_size = sizeof (struct GNUNET_LOCKMANAGER_Message) + domain_name_len; + reply = GNUNET_malloc (reply_size); + reply->header.size = htons (reply_size); + reply->header.type = htons (GNUNET_MESSAGE_TYPE_LOCKMANAGER_SUCCESS); + reply->lock = htonl (lock_num); + strncpy ((char *) &reply[1], domain_name, domain_name_len); + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Sending SUCCESS message for lock with num: %u, domain: %s\n", + lock_num, domain_name); + GNUNET_SERVER_notify_transmit_ready (client, + reply_size, + TIMEOUT, + &transmit_notify, + reply); +} + + +/** + * Handler for GNUNET_MESSAGE_TYPE_LOCKMANAGER_ACQUIRE + * + * @param cls NULL + * @param client the client sending this message + * @param message GNUNET_MESSAGE_TYPE_LOCKMANAGER_ACQUIRE message + */ +static void +handle_acquire (void *cls, + struct GNUNET_SERVER_Client *client, + const struct GNUNET_MessageHeader *message) +{ + const struct GNUNET_LOCKMANAGER_Message *request; + const char *domain_name; + struct Lock *lock; + struct ClientList *cl_entry; + uint32_t lock_num; + uint16_t msize; + + msize = htons (message->size); + if (msize <= sizeof (struct GNUNET_LOCKMANAGER_Message)) + { + GNUNET_break (0); + GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); + return; + } + request = (struct GNUNET_LOCKMANAGER_Message *) message; + domain_name = (const char *) &request[1]; + msize -= sizeof (struct GNUNET_LOCKMANAGER_Message); + if ('\0' != domain_name[msize]) + { + GNUNET_break (0); + GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); + return; + } + lock_num = ntohl (request->lock); + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Received an ACQUIRE message for lock num: %u domain: %s\n", + lock_num, domain_name); + if (NULL == (cl_entry = cl_find_client (client))) + cl_entry = cl_add_client (client); /* Add client if not in client list */ + if (NULL != (lock = find_lock (domain_name,lock_num))) + { + if (lock->cl_entry == cl_entry) + { /* Client is requesting a lock it already owns */ + GNUNET_break (0); + GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); + return; + } + lock_wl_add_client (lock, cl_entry); + cl_ll_add_lock (cl_entry, lock); + } + else /* Lock not present */ + { + lock = add_lock (domain_name, lock_num); + lock->cl_entry = cl_entry; + cl_ll_add_lock (cl_entry, lock); + send_success_msg (cl_entry->client, domain_name, lock_num); + } + GNUNET_SERVER_receive_done (client, GNUNET_OK); +} + + +/** + * This function gives the lock to the first client in the wait list of the + * lock. If no clients are currently waiting for this lock, the lock is then + * destroyed. + * + * @param lock the lock which has to be processed for release + */ +static void +process_lock_release (struct Lock *lock) +{ + struct WaitList *wl_entry; + + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Processing lock release for lock with num: %u, domain: %s\n", + lock->lock_num, lock->domain_name); + wl_entry = lock->wl_head; + if (NULL == wl_entry) + { + remove_lock (lock); /* No clients waiting for this lock - delete */ + return; + } + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Giving lock to a client from wait list\n"); + lock->cl_entry = wl_entry->cl_entry; + lock_wl_remove(lock, wl_entry); + send_success_msg (lock->cl_entry->client, + lock->domain_name, + lock->lock_num); + return; +} + + +/** + * Handle for GNUNET_MESSAGE_TYPE_LOCKMANAGER_RELEASE + * + * @param cls NULL + * @param client the client sending this message + * @param message the LOCKMANAGER_RELEASE message + */ +static void +handle_release (void *cls, + struct GNUNET_SERVER_Client *client, + const struct GNUNET_MessageHeader *message) +{ + const struct GNUNET_LOCKMANAGER_Message *request; + struct ClientList *cl_entry; + struct WaitList *wl_entry; + struct LockList *ll_entry; + const char *domain_name; + struct Lock *lock; + uint32_t lock_num; + uint16_t msize; + + msize = ntohs (message->size); + if (msize <= sizeof (struct GNUNET_LOCKMANAGER_Message)) + { + GNUNET_break (0); + GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); + return; + } + request = (const struct GNUNET_LOCKMANAGER_Message *) message; + domain_name = (const char *) &request[1]; + msize -= sizeof (struct GNUNET_LOCKMANAGER_Message); + if ('\0' != domain_name[msize-1]) + { + GNUNET_break (0); + GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); + return; + + + } + lock_num = ntohl (request->lock); + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Received RELEASE message for lock with num: %d, domain: %s\n", + lock_num, domain_name); + if (NULL == (cl_entry = cl_find_client (client))) + { + GNUNET_break(0); + GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); + return; + } + lock = find_lock (domain_name, lock_num); + if(NULL == lock) + { + GNUNET_break (0); + GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); + return; + } + if (NULL == (ll_entry = cl_ll_find_lock (cl_entry, lock))) + { + GNUNET_break (0); + GNUNET_SERVER_receive_done (client, GNUNET_SYSERR); + return; + } + cl_ll_remove_lock (cl_entry, ll_entry); + if (cl_entry == lock->cl_entry) + { + process_lock_release (lock); + GNUNET_SERVER_receive_done (client, GNUNET_OK); + return; + } + /* remove 'client' from wait list (check that it is not there...) */ + if (NULL != (wl_entry = lock_wl_find (lock, cl_entry))) + { + lock_wl_remove (lock, wl_entry); + } + GNUNET_SERVER_receive_done (client, GNUNET_OK); +} + + +/** + * Callback for client disconnect + * + * @param cls NULL + * @param client the client which has disconnected + */ +static void +client_disconnect_cb (void *cls, struct GNUNET_SERVER_Client *client) +{ + struct ClientList *cl_entry; + struct LockList *ll_entry; + struct Lock *lock; + + if (NULL == client) + return; + LOG (GNUNET_ERROR_TYPE_DEBUG, + "A client has been disconnected -- freeing its locks and resources\n"); + cl_entry = cl_find_client (client); + if (NULL == cl_entry) + return; + while (NULL != (ll_entry = cl_entry->ll_head)) + { + lock = ll_entry->lock; + cl_ll_remove_lock (cl_entry, ll_entry); + process_lock_release (lock); + } + cl_remove_client (cl_entry); +} + + +/** + * Hashmap Iterator to delete lock entries in hash map + * + * @param cls NULL + * @param key current key code + * @param value value in the hash map + * @return GNUNET_YES if we should continue to + * iterate, + * GNUNET_NO if not. + */ +static int +lock_delete_iterator (void *cls, + const GNUNET_HashCode * key, + void *value) +{ + struct Lock *lock = value; + + GNUNET_assert (NULL != lock); + while (NULL != lock->wl_head) + { + lock_wl_remove (lock, lock->wl_head); + } + GNUNET_assert (GNUNET_YES == + GNUNET_CONTAINER_multihashmap_remove(lock_map, + key, + lock)); + GNUNET_free (lock->domain_name); + GNUNET_free (lock); + return GNUNET_YES; +} + + +/** + * Task to clean up and shutdown nicely + * + * @param cls NULL + * @param tc the TaskContext from scheduler + */ +static void +shutdown_task (void *cls, + const struct GNUNET_SCHEDULER_TaskContext *tc) +{ + LOG (GNUNET_ERROR_TYPE_DEBUG, + "Shutting down lock manager\n"); + /* Clean the global ClientList */ + while (NULL != cl_head) + { + while (NULL != cl_head->ll_head) /* Clear the LockList */ + { + cl_ll_remove_lock (cl_head, cl_head->ll_head); + } + cl_remove_client (cl_head); + } + /* Clean the global hash table */ + GNUNET_CONTAINER_multihashmap_iterate (lock_map, + &lock_delete_iterator, + NULL); + GNUNET_assert (0 == GNUNET_CONTAINER_multihashmap_size (lock_map)); + GNUNET_CONTAINER_multihashmap_destroy (lock_map); +} + + +/** + * Lock manager setup + * + * @param cls closure + * @param server the initialized server + * @param cfg configuration to use + */ +static void +lockmanager_run (void *cls, + struct GNUNET_SERVER_Handle * server, + const struct GNUNET_CONFIGURATION_Handle *cfg) +{ + static const struct GNUNET_SERVER_MessageHandler message_handlers[] = + { + {&handle_acquire, NULL, GNUNET_MESSAGE_TYPE_LOCKMANAGER_ACQUIRE, 0}, + {&handle_release, NULL, GNUNET_MESSAGE_TYPE_LOCKMANAGER_RELEASE, 0}, + {NULL} + }; + GNUNET_SERVER_add_handlers (server, + message_handlers); + GNUNET_SERVER_disconnect_notify (server, + &client_disconnect_cb, + NULL); + lock_map = GNUNET_CONTAINER_multihashmap_create (30); + GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, + &shutdown_task, + NULL); +} + + +/** + * The starting point of execution + */ +int main (int argc, char *const *argv) +{ + return + (GNUNET_OK == + GNUNET_SERVICE_run (argc, + argv, + "lockmanager", + GNUNET_SERVICE_OPTION_NONE, + &lockmanager_run, + NULL)) ? 0 : 1; +} |