Merge pull request #650 from FullName/ID-IP-basic

Significantly trimmed down version of an ID<=>IP cache.

1 files changed, 87 insertions, 0 deletions

diff --git a/toxcore/assoc.h b/toxcore/assoc.h
new file mode 100644
index 00000000..ee9e5e21
--- /dev/null
+++ b/toxcore/assoc.h
@@ -0,0 +1,87 @@
+
+#ifndef __ASSOC_H__
+#define __ASSOC_H__
+
+/* used by rendezvous */
+#define ASSOC_AVAILABLE
+
+/* For the legalese parts, see tox.h. */
+
+/*
+ * Module to store currently unused ID <=> IP associations
+ * for a potential future use
+ */
+
+typedef struct IP_Port IP_Port;
+typedef struct Assoc Assoc;
+
+/*****************************************************************************/
+
+/* custom distance handler, if it's not ID-distance based
+ * return values exactly like id_closest() */
+typedef int (*Assoc_distance_relative_callback)(Assoc *assoc, void *callback_data, uint8_t *client_id,
+        uint8_t *client_id1, uint8_t *client_id2);
+
+#define DISTANCE_INDEX_DISTANCE_BITS 44
+
+/* absolute distance: can be same for different client_id_check values
+ * return value should have DISTANCE_INDEX_DISTANCE_BITS valid bits */
+typedef uint64_t (*Assoc_distance_absolute_callback)(Assoc *assoc, void *callback_data,
+        uint8_t *client_id_ref, uint8_t *client_id_check);
+
+/*****************************************************************************/
+
+/* Central entry point for new associations: add a new candidate to the cache
+ * returns 1 if entry is stored, 2 if existing entry was updated, 0 else */
+uint8_t Assoc_add_entry(Assoc *assoc, uint8_t *id, IPPTs *ippts_send, IP_Port *ipp_recv, uint8_t used);
+
+/*****************************************************************************/
+
+typedef struct Assoc_close_entries {
+    uint8_t                           *wanted_id;          /* the target client_id */
+    void                              *custom_data;        /* given to distance functions */
+
+    Assoc_distance_relative_callback   distance_relative_func;
+    Assoc_distance_absolute_callback   distance_absolute_func;
+
+    uint8_t                            count_good;   /* that many should be "good" w.r.t. timeout */
+    uint8_t                            count;        /* allocated number of close_indices */
+    Client_data                      **result;
+} Assoc_close_entries;
+
+/* find up to close_count nodes to put into close_nodes_used of ID_Nodes
+ * the distance functions can be NULL, then standard distance functions will be used
+ * the caller is responsible for allocating close_indices of sufficient size
+ *
+ * returns 0 on error
+ * returns the number of found nodes and the list of indices usable by Assoc_client()
+ *    the caller is assumed to be registered from Assoc_register_callback()
+ *    if they aren't, they should copy the Client_data and call Assoc_client_drop()
+ */
+uint8_t Assoc_get_close_entries(Assoc *assoc, Assoc_close_entries *close_entries);
+
+/*****************************************************************************/
+
+/* create: default sizes (6, 5 => 320 entries) */
+Assoc *new_Assoc_default(uint8_t *public_id);
+
+/* create: customized sizes
+ * total is (2^bits) * entries
+ * bits should be between 2 and 15 (else it's trimmed)
+ * entries will be reduced to the closest prime smaller or equal
+ *
+ * preferably bits should be large and entries small to ensure spread
+ * in the search space (e. g. 5, 5 is preferable to 2, 41) */
+Assoc *new_Assoc(size_t bits, size_t entries, uint8_t *public_id);
+
+/* public_id changed (loaded), update which entry isn't stored */
+void Assoc_self_client_id_changed(Assoc *assoc, uint8_t *public_id);
+
+/* destroy */
+void kill_Assoc(Assoc *assoc);
+
+#ifdef LOGGING
+void Assoc_status(Assoc *assoc);
+#endif
+
+#endif /* !__ASSOC_H__ */