#ifndef FS_H
#define FS_H
+#include "gnunet_constants.h"
#include "gnunet_datastore_service.h"
#include "gnunet_fs_service.h"
#define MAX_INLINE_SIZE 65536
+/**
+ * Blocksize to use when hashing files
+ * for indexing (blocksize for IO, not for
+ * the DBlocks). Larger blocksizes can
+ * be more efficient but will be more disruptive
+ * as far as the scheduler is concerned.
+ */
+#define HASHING_BLOCKSIZE (1024 * 1024)
+
+/**
+ * Number of bits we set per entry in the bloomfilter.
+ * Do not change!
+ */
+#define BLOOMFILTER_K 16
+
+/**
+ * By how much (in ms) do we decrement the TTL
+ * at each hop?
+ */
+#define TTL_DECREMENT 5000
+
+/**
+ * How long are we willing to wait for the datastore to be ready to
+ * process a request for a query without priority?
+ */
+#define BASIC_DATASTORE_REQUEST_DELAY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
+
+
+/**
+ * How long are we willing to wait for the core to be ready to
+ * transmit a reply to the target peer (if we can not transmit
+ * until then, we will discard the reply).
+ */
+#define ACCEPTABLE_REPLY_DELAY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 5)
+
+
+/**
+ * Bandwidth value of an (effectively) 0-priority query.
+ */
+#define QUERY_BANDWIDTH_VALUE 0.001
+
+/**
+ * Bandwidth value of a 0-priority content (must be
+ * fairly high compared to query since content is
+ * typically significantly larger -- and more valueable
+ * since it can take many queries to get one piece of
+ * content).
+ */
+#define CONTENT_BANDWIDTH_VALUE 0.8
+
+/**
+ * By which amount do we decrement the TTL for simple forwarding /
+ * indirection of the query; in milli-seconds. Set somewhat in
+ * accordance to your network latency (above the time it'll take you
+ * to send a packet and get a reply).
+ */
+#define TTL_DECREMENT 5000
+
+/**
+ * Until which load do we consider the peer idle and do not
+ * charge at all? (should be larger than GNUNET_IDLE_LOAD_THRESHOLD used
+ * by the rest of the code)!
+ */
+#define IDLE_LOAD_THRESHOLD ((100 + GNUNET_CONSTANTS_IDLE_LOAD_THRESHOLD) / 2)
+
+
/**
* @brief content hash key
* (for operational persistence).
*/
char *serialization;
-
+
/**
- * In-memory cache of the current CHK tree.
- * This struct will contain the CHK values
- * from the root to the currently processed
- * node in the tree as identified by
- * "current_depth" and "publish_offset".
- * The "chktree" will be initially NULL,
- * then allocated to a sufficient number of
- * entries for the size of the file and
- * finally freed once the upload is complete.
+ * Encoder being used to publish this file.
*/
- struct ContentHashKey *chk_tree;
+ struct GNUNET_FS_TreeEncoder *te;
/**
* Error message (non-NULL if this operation
* failed).
*/
char *emsg;
-
- /**
- * Number of entries in "chk_tree".
- */
- unsigned int chk_tree_depth;
-
- /**
- * Depth in the CHK-tree at which we are
- * currently publishing. 0 is the root
- * of the tree.
- */
- unsigned int current_depth;
-
- /**
- * How many bytes of this file or directory have been
- * published so far?
- */
- uint64_t publish_offset;
/**
* Data describing either the file or the directory.
*/
void *reader_cls;
+ /**
+ * Name of the file (must be an absolute path).
+ * Only required for indexing. FIXME: not yet
+ * initialized!
+ */
+ char *filename;
+
+ /**
+ * If this file is being indexed, this value
+ * is set to the hash over the entire file
+ * (when the indexing process is started).
+ * Otherwise this field is not used.
+ */
+ GNUNET_HashCode file_id;
+
/**
* Size of the file (in bytes).
*/
/**
* Desired anonymity level.
*/
- unsigned int anonymity;
+ uint32_t anonymity;
/**
* Desired priority (for keeping the content in the DB).
*/
- unsigned int priority;
+ uint32_t priority;
};
*/
struct GNUNET_CLIENT_Connection *client;
+ /**
+ * How many downloads probing availability
+ * of search results do we have running
+ * right now?
+ */
+ unsigned int active_probes;
+
+ /**
+ * General flags.
+ */
+ enum GNUNET_FS_Flags flags;
};
*/
char *nuid;
+ /**
+ * Our own client handle for the FS service;
+ * only briefly used when we start to index a
+ * file, otherwise NULL.
+ */
+ struct GNUNET_CLIENT_Connection *client;
+
+ /**
+ * Current position in the file-tree for the
+ * upload.
+ */
+ struct GNUNET_FS_FileInformation *fi_pos;
+
+ /**
+ * Connection to the datastore service.
+ */
+ struct GNUNET_DATASTORE_Handle *dsh;
+
/**
* ID of the task performing the upload. NO_TASK
* if the upload has completed.
enum GNUNET_FS_PublishOptions options;
/**
- * Current position in the file-tree for the
- * upload.
+ * Space reservation ID with datastore service
+ * for this upload.
*/
- struct GNUNET_FS_FileInformation *fi_pos;
+ int rid;
+};
+
+/**
+ * Phases of unindex processing (state machine).
+ */
+enum UnindexState
+ {
+ /**
+ * We're currently hashing the file.
+ */
+ UNINDEX_STATE_HASHING = 0,
+
+ /**
+ * We're notifying the FS service about
+ * the unindexing.
+ */
+ UNINDEX_STATE_FS_NOTIFY = 1,
+
+ /**
+ * We're telling the datastore to delete
+ * the respective entries.
+ */
+ UNINDEX_STATE_DS_REMOVE = 2,
+
+ /**
+ * We're done.
+ */
+ UNINDEX_STATE_COMPLETE = 3,
+
+ /**
+ * We've encountered a fatal error.
+ */
+ UNINDEX_STATE_ERROR = 4,
+
+ /**
+ * We've been aborted. The next callback should clean up the
+ * struct.
+ */
+ UNINDEX_STATE_ABORTED = 5
+ };
+
+
+/**
+ * Handle for controlling an unindexing operation.
+ */
+struct GNUNET_FS_UnindexContext
+{
+
/**
- * Connection to the datastore service.
+ * Global FS context.
+ */
+ struct GNUNET_FS_Handle *h;
+
+ /**
+ * Name of the file that we are unindexing.
+ */
+ char *filename;
+
+ /**
+ * Connection to the FS service,
+ * only valid during the UNINDEX_STATE_FS_NOTIFY
+ * phase.
+ */
+ struct GNUNET_CLIENT_Connection *client;
+
+ /**
+ * Connection to the datastore service,
+ * only valid during the UNINDEX_STATE_DS_NOTIFY
+ * phase.
*/
struct GNUNET_DATASTORE_Handle *dsh;
/**
- * Space reservation ID with datastore service
- * for this upload.
+ * Pointer kept for the client.
*/
- int rid;
+ void *client_info;
+
+ /**
+ * Merkle-ish tree encoder context.
+ */
+ struct GNUNET_FS_TreeEncoder *tc;
+
+ /**
+ * Handle used to read the file.
+ */
+ struct GNUNET_DISK_FileHandle *fh;
+
+ /**
+ * Overall size of the file.
+ */
+ uint64_t file_size;
+
+ /**
+ * When did we start?
+ */
+ struct GNUNET_TIME_Absolute start_time;
+
+ /**
+ * Hash of the file's contents (once
+ * computed).
+ */
+ GNUNET_HashCode file_id;
+
+ /**
+ * Current operatinonal phase.
+ */
+ enum UnindexState state;
+
};
/**
- * Handle for controlling an unindexing operation.
+ * Information we store for each search result.
*/
-struct GNUNET_FS_UnindexContext
+struct SearchResult
{
+
+ /**
+ * URI to which this search result
+ * refers to.
+ */
+ struct GNUNET_FS_Uri *uri;
+
+ /**
+ * Metadata for the search result.
+ */
+ struct GNUNET_CONTAINER_MetaData *meta;
+
+ /**
+ * Client info for this search result.
+ */
+ void *client_info;
+
+ /**
+ * ID of a job that is currently probing
+ * this results' availability (NULL if we
+ * are not currently probing).
+ */
+ struct GNUNET_FS_DownloadContext *probe_ctx;
+
+ /**
+ * ID of the task that will clean up the probe_ctx
+ * should it not complete on time (and that will
+ * need to be cancelled if we clean up the search
+ * result before then).
+ */
+ GNUNET_SCHEDULER_TaskIdentifier probe_cancel_task;
+
+ /**
+ * Number of mandatory keywords for which
+ * we have NOT yet found the search result;
+ * when this value hits zero, the search
+ * result is given to the callback.
+ */
+ uint32_t mandatory_missing;
+
+ /**
+ * Number of optional keywords under which
+ * this result was also found.
+ */
+ uint32_t optional_support;
+
+ /**
+ * Number of availability tests that
+ * have succeeded for this result.
+ */
+ uint32_t availability_success;
+
+ /**
+ * Number of availability trials that we
+ * have performed for this search result.
+ */
+ uint32_t availability_trials;
+
+};
+
+
+/**
+ * Information we keep for each keyword in
+ * a keyword search.
+ */
+struct SearchRequestEntry
+{
+ /**
+ * Hash of the original keyword, also known as the
+ * key (for decrypting the KBlock).
+ */
+ GNUNET_HashCode key;
+
+ /**
+ * Hash of the public key, also known as the query.
+ */
+ GNUNET_HashCode query;
+
+ /**
+ * Map that contains a "struct SearchResult" for each result that
+ * was found under this keyword. Note that the entries will point
+ * to the same locations as those in the master result map (in
+ * "struct GNUNET_FS_SearchContext"), so they should not be freed.
+ * The key for each entry is the XOR of the key and query in the CHK
+ * URI (as a unique identifier for the search result).
+ */
+ struct GNUNET_CONTAINER_MultiHashMap *results;
+
+ /**
+ * Is this keyword a mandatory keyword
+ * (started with '+')?
+ */
+ int mandatory;
+
};
*/
struct GNUNET_FS_SearchContext
{
+ /**
+ * Handle to the global FS context.
+ */
+ struct GNUNET_FS_Handle *h;
+
+ /**
+ * List of keywords that we're looking for.
+ */
+ struct GNUNET_FS_Uri *uri;
+
+ /**
+ * For update-searches, link to the
+ * base-SKS search that triggered the
+ * update search; otherwise NULL.
+ */
+ struct GNUNET_FS_SearchContext *parent;
+
+ /**
+ * Connection to the FS service.
+ */
+ struct GNUNET_CLIENT_Connection *client;
+
+ /**
+ * Pointer we keep for the client.
+ */
+ void *client_info;
+
+ /**
+ * Map that contains a "struct SearchResult" for each result that
+ * was found in the search. The key for each entry is the XOR of
+ * the key and query in the CHK URI (as a unique identifier for the
+ * search result).
+ */
+ struct GNUNET_CONTAINER_MultiHashMap *master_result_map;
+
+ /**
+ * Per-keyword information for a keyword search.
+ * This array will have exactly as many entries
+ * as there were keywords.
+ */
+ struct SearchRequestEntry *requests;
+
+ /**
+ * When did we start?
+ */
+ struct GNUNET_TIME_Absolute start_time;
+
+ /**
+ * ID of a task that is using this struct
+ * and that must be cancelled when the search
+ * is being stopped (if not GNUNET_SCHEDULER_NO_TASK).
+ * Used for the task that adds some artificial
+ * delay when trying to reconnect to the FS
+ * service.
+ */
+ GNUNET_SCHEDULER_TaskIdentifier task;
+
+ /**
+ * Anonymity level for the search.
+ */
+ uint32_t anonymity;
+
+ /**
+ * Number of mandatory keywords in this query.
+ */
+ uint32_t mandatory_count;
+};
+
+
+/**
+ * Information about an active download request.
+ */
+struct DownloadRequest
+{
+ /**
+ * While pending, we keep all download requests
+ * in a linked list.
+ */
+ struct DownloadRequest *next;
+
+ /**
+ * CHK for the request.
+ */
+ struct ContentHashKey chk;
+
+ /**
+ * Offset of the corresponding block.
+ */
+ uint64_t offset;
+
+ /**
+ * Depth of the corresponding block in the tree.
+ */
+ unsigned int depth;
+
+ /**
+ * Set if this request is currently in the linked list of pending
+ * requests. Needed in case we get a response for a request that we
+ * have not yet send (due to FS bug or two blocks with identical
+ * content); in this case, we would need to remove the block from
+ * the pending list (and need a fast way to check if the block is on
+ * it).
+ */
+ int is_pending;
+
};
*/
struct GNUNET_FS_DownloadContext
{
+
+ /**
+ * Global FS context.
+ */
+ struct GNUNET_FS_Handle *h;
+
+ /**
+ * Connection to the FS service.
+ */
+ struct GNUNET_CLIENT_Connection *client;
+
+ /**
+ * Parent download (used when downloading files
+ * in directories).
+ */
+ struct GNUNET_FS_DownloadContext *parent;
+
+ /**
+ * Context kept for the client.
+ */
+ void *client_info;
+
+ /**
+ * URI that identifies the file that
+ * we are downloading.
+ */
+ struct GNUNET_FS_Uri *uri;
+
+ /**
+ * Known meta-data for the file (can be NULL).
+ */
+ struct GNUNET_CONTAINER_MetaData *meta;
+
+ /**
+ * Error message, NULL if we're doing OK.
+ */
+ char *emsg;
+
+ /**
+ * Where are we writing the data (name of the
+ * file, can be NULL!).
+ */
+ char *filename;
+
+ /**
+ * Map of active requests (those waiting
+ * for a response). The key is the hash
+ * of the encryped block (aka query).
+ */
+ struct GNUNET_CONTAINER_MultiHashMap *active;
+
+ /**
+ * Linked list of pending requests.
+ */
+ struct DownloadRequest *pending;
+
+ /**
+ * The file handle, NULL if we don't create
+ * a file.
+ */
+ struct GNUNET_DISK_FileHandle *handle;
+
+ /**
+ * Identity of the peer having the content, or all-zeros
+ * if we don't know of such a peer.
+ */
+ struct GNUNET_PeerIdentity target;
+
+ /**
+ * ID of a task that is using this struct
+ * and that must be cancelled when the download
+ * is being stopped (if not GNUNET_SCHEDULER_NO_TASK).
+ * Used for the task that adds some artificial
+ * delay when trying to reconnect to the FS
+ * service.
+ */
+ GNUNET_SCHEDULER_TaskIdentifier task;
+
+ /**
+ * What was the size of the file on disk that we're downloading
+ * before we started? Used to detect if there is a point in
+ * checking an existing block on disk for matching the desired
+ * content. 0 if the file did not exist already.
+ */
+ uint64_t old_file_size;
+
+ /**
+ * What is the first offset that we're interested
+ * in?
+ */
+ uint64_t offset;
+
+ /**
+ * How many bytes starting from offset are desired?
+ * This is NOT the overall length of the file!
+ */
+ uint64_t length;
+
+ /**
+ * How many bytes have we already received within
+ * the specified range (DBlocks only).
+ */
+ uint64_t completed;
+
+ /**
+ * Time download was started.
+ */
+ struct GNUNET_TIME_Absolute start_time;
+
+ /**
+ * Desired level of anonymity.
+ */
+ uint32_t anonymity;
+
+ /**
+ * The depth of the file-tree.
+ */
+ unsigned int treedepth;
+
+ /**
+ * Options for the download.
+ */
+ enum GNUNET_FS_DownloadOptions options;
+
};
struct GNUNET_FS_Namespace
};
+/**
+ * @brief index block (indexing a DBlock that
+ * can be obtained directly from reading
+ * the plaintext file)
+ */
+struct OnDemandBlock
+{
+ /**
+ * Hash code of the entire content of the
+ * file that was indexed (used to uniquely
+ * identify the plaintext file).
+ */
+ GNUNET_HashCode file_id;
+
+ /**
+ * At which offset should we be able to find
+ * this on-demand encoded block?
+ */
+ uint64_t offset GNUNET_PACKED;
+
+};
+
+
/**
* @brief keyword block (advertising data under a keyword)
*/
};
+/**
+ * Message sent from a GNUnet (fs) publishing
+ * activity to the gnunet-fs-service to
+ * initiate indexing of a file. The service
+ * is supposed to check if the specified file
+ * is available and has the same cryptographic
+ * hash. It should then respond with either
+ * a confirmation or a denial.
+ *
+ * On OSes where this works, it is considered
+ * acceptable if the service only checks that
+ * the path, device and inode match (it can
+ * then be assumed that the hash will also match
+ * without actually computing it; this is an
+ * optimization that should be safe given that
+ * the client is not our adversary).
+ */
struct IndexStartMessage
{
+ /**
+ * Message type will be
+ * GNUNET_MESSAGE_TYPE_FS_INDEX_START.
+ */
+ struct GNUNET_MessageHeader header;
+
+ /**
+ * ID of device containing the file, as seen by the client. This
+ * device ID is obtained using a call like "statvfs" (and converting
+ * the "f_fsid" field to a 32-bit big-endian number). Use 0 if the
+ * OS does not support this, in which case the service must do a
+ * full hash recomputation.
+ */
+ uint32_t device GNUNET_PACKED;
+
+ /**
+ * Inode of the file on the given device, as seen by the client
+ * ("st_ino" field from "struct stat"). Use 0 if the OS does not
+ * support this, in which case the service must do a full hash
+ * recomputation.
+ */
+ uint64_t inode GNUNET_PACKED;
+
+ /**
+ * Hash of the file that we would like to index.
+ */
+ GNUNET_HashCode file_id;
+
+ /* this is followed by a 0-terminated
+ filename of a file with the hash
+ "file_id" as seen by the client */
+
+};
+
+
+/**
+ * Message send by FS service in response to a request
+ * asking for a list of all indexed files.
+ */
+struct IndexInfoMessage
+{
+ /**
+ * Message type will be
+ * GNUNET_MESSAGE_TYPE_FS_INDEX_LIST_ENTRY.
+ */
+ struct GNUNET_MessageHeader header;
+
+ /**
+ * Always zero.
+ */
+ uint32_t reserved GNUNET_PACKED;
+
+ /**
+ * Hash of the indexed file.
+ */
+ GNUNET_HashCode file_id;
+
+ /* this is followed by a 0-terminated
+ filename of a file with the hash
+ "file_id" as seen by the client */
+
+};
+
+
+/**
+ * Message sent from a GNUnet (fs) unindexing
+ * activity to the gnunet-fs-service to
+ * indicate that a file will be unindexed. The service
+ * is supposed to remove the file from the
+ * list of indexed files and response with
+ * a confirmation message (even if the file
+ * was already not on the list).
+ */
+struct UnindexMessage
+{
+
+ /**
+ * Message type will be
+ * GNUNET_MESSAGE_TYPE_FS_UNINDEX.
+ */
+ struct GNUNET_MessageHeader header;
+
+ /**
+ * Always zero.
+ */
+ uint32_t reserved GNUNET_PACKED;
+
+ /**
+ * Hash of the file that we will unindex.
+ */
+ GNUNET_HashCode file_id;
+
+};
+
+
+/**
+ * Message sent from a GNUnet (fs) search
+ * activity to the gnunet-fs-service to
+ * start a search.
+ */
+struct SearchMessage
+{
+
+ /**
+ * Message type will be
+ * GNUNET_MESSAGE_TYPE_FS_START_SEARCH.
+ */
+ struct GNUNET_MessageHeader header;
+
+ /**
+ * Should be zero.
+ */
+ int32_t reserved GNUNET_PACKED;
+
+ /**
+ * Type of the content that we're looking for.
+ * 0 for any.
+ */
+ uint32_t type GNUNET_PACKED;
+
+ /**
+ * Desired anonymity level, big-endian.
+ */
+ uint32_t anonymity_level GNUNET_PACKED;
+
+ /**
+ * If the request is for a DBLOCK or IBLOCK, this is the identity of
+ * the peer that is known to have a response. Set to all-zeros if
+ * such a target is not known (note that even if OUR anonymity
+ * level is >0 we may happen to know the responder's identity;
+ * nevertheless, we should probably not use it for a DHT-lookup
+ * or similar blunt actions in order to avoid exposing ourselves).
+ * <p>
+ * If the request is for an SBLOCK, this is the identity of the
+ * pseudonym to which the SBLOCK belongs.
+ * <p>
+ * If the request is for a KBLOCK, "target" must be all zeros.
+ */
+ GNUNET_HashCode target;
+
+ /**
+ * Hash of the keyword (aka query) for KBLOCKs; Hash of
+ * the CHK-encoded block for DBLOCKS and IBLOCKS (aka query)
+ * and hash of the identifier XORed with the target for
+ * SBLOCKS (aka query).
+ */
+ GNUNET_HashCode query;
+
+ /* this is followed by the hash codes of already-known
+ results (which should hence be excluded from what
+ the service returns); naturally, this only applies
+ to queries that can have multiple results, such as
+ those for KBLOCKS (KSK) and SBLOCKS (SKS) */
};
+/**
+ * Response from FS service with a result for
+ * a previous FS search. Note that queries
+ * for DBLOCKS and IBLOCKS that have received
+ * a single response are considered done.
+ */
+struct ContentMessage
+{
+
+ /**
+ * Message type will be
+ * GNUNET_MESSAGE_TYPE_FS_CONTENT.
+ */
+ struct GNUNET_MessageHeader header;
+
+ /**
+ * Type of the content that was found,
+ * should never be 0.
+ */
+ uint32_t type GNUNET_PACKED;
+
+ /**
+ * When will this result expire?
+ */
+ struct GNUNET_TIME_AbsoluteNBO expiration;
+
+ /* followed by the actual block of data */
+
+};
+
+/**
+ * Only the (mandatory) query is included.
+ */
+#define GET_MESSAGE_BIT_QUERY_ONLY 0
+
+/**
+ * The peer identity of a peer waiting for the
+ * reply is included (used if the response
+ * should be transmitted to someone other than
+ * the sender of the GET).
+ */
+#define GET_MESSAGE_BIT_RETURN_TO 1
+
+/**
+ * The hash of the public key of the target
+ * namespace is included (for SKS queries).
+ */
+#define GET_MESSAGE_BIT_SKS_NAMESPACE 2
+
+/**
+ * The peer identity of a peer that had claimed to have the content
+ * previously is included (can be used if responder-anonymity is not
+ * desired; note that the precursor presumably lacked a direct
+ * connection to the specified peer; still, the receiver is in no way
+ * required to limit forwarding only to the specified peer, it should
+ * only prefer it somewhat if possible).
+ */
+#define GET_MESSAGE_BIT_TRANSMIT_TO 4
+
+
+/**
+ * Message sent between peers asking for FS-content.
+ */
+struct GetMessage
+{
+
+ /**
+ * Message type will be GNUNET_MESSAGE_TYPE_FS_GET.
+ */
+ struct GNUNET_MessageHeader header;
+
+ /**
+ * Type of the query (block type).
+ */
+ uint32_t type GNUNET_PACKED;
+
+ /**
+ * How important is this request (network byte order)
+ */
+ uint32_t priority GNUNET_PACKED;
+
+ /**
+ * Relative time to live in GNUNET_CRON_MILLISECONDS (network byte order)
+ */
+ int32_t ttl GNUNET_PACKED;
+
+ /**
+ * The content hash should be mutated using this value
+ * before checking against the bloomfilter (used to
+ * get many different filters for the same hash codes).
+ * The number should be in big-endian format when used
+ * for mingling.
+ */
+ int32_t filter_mutator GNUNET_PACKED;
+
+ /**
+ * Which of the optional hash codes are present at the end of the
+ * message? See GET_MESSAGE_BIT_xx constants. For each bit that is
+ * set, an additional GNUNET_HashCode with the respective content
+ * (in order of the bits) will be appended to the end of the GET
+ * message.
+ */
+ uint32_t hash_bitmap GNUNET_PACKED;
+
+ /**
+ * Hashcodes of the file(s) we're looking for.
+ * Details depend on the query type.
+ */
+ GNUNET_HashCode query GNUNET_PACKED;
+
+ /* this is followed by hash codes
+ as specified in the "hash_bitmap";
+ after that, an optional bloomfilter
+ (with bits set for replies that should
+ be suppressed) can be present */
+};
+
+
+/**
+ * Message sent between peers providing FS-content.
+ */
+struct PutMessage
+{
+
+ /**
+ * Message type will be GNUNET_MESSAGE_TYPE_FS_PUT.
+ */
+ struct GNUNET_MessageHeader header;
+
+ /**
+ * Type of the block (in big endian).
+ */
+ uint32_t type GNUNET_PACKED;
+
+ /**
+ * When does this result expire?
+ */
+ struct GNUNET_TIME_RelativeNBO expiration;
+
+ /* this is followed by the actual encrypted content */
+
+};
+
#endif