Peers are now dumped on shutdown in a persistence cache and reloaded on startup, which is good enough for clients right now. Supernodes will get something else for long-term authoritative identity caching.

node/Constants.hpp

@@ -208,6 +208,11 @@ error_no_ZT_ARCH_defined;
  */
 #define ZT_DB_CLEAN_PERIOD 300000
 
+/**
+ * How long to remember peers in RAM if they haven't been used
+ */
+#define ZT_PEER_IN_MEMORY_EXPIRATION 600000
+
 /**
  * Delay between WHOIS retries in ms
  */