Added defines for SDK behavior

include/ZeroTierSDK.h

@@ -26,7 +26,7 @@
 /****************************************************************************/
 
 #define ZT_SDK_MTU                         ZT_MAX_MTU
-#define ZT_PHY_POLL_INTERVAL          50  // ms
+#define ZT_PHY_POLL_INTERVAL               10  // ms
 #define ZT_ACCEPT_RECHECK_DELAY            100 // ms (for blocking zts_accept() calls)
 #define ZT_CONNECT_RECHECK_DELAY           100 // ms (for blocking zts_connect() calls)
 
@@ -48,13 +48,22 @@
 #define ZT_VER_STR_LEN                     6
 #define ZT_HOME_PATH_MAX_LEN               128
 
-#define ZT_ERR_OK                           0
-
 #define ZT_SOCK_STATE_NONE                 100
 #define ZT_SOCK_STATE_UNHANDLED_CONNECTED  101
 #define ZT_SOCK_STATE_CONNECTED            102
 #define ZT_SOCK_STATE_LISTENING            103
 
+#define ZT_ERR_OK                          0
+#define ZT_ERR_GENERAL_FAILURE             -88
+
+// Since extra time is required to send a mesage via a socket through the
+// stack and ZT service, calling a zclose() immediately after a "successful"
+// zwrite() might cause data loss, for this reason, sockets will SO_LINGER for
+// a short period of time by default as a precaution.
+
+#define ZT_SOCK_BEHAVIOR_LINGER            true
+#define ZT_SOCK_BEHAVIOR_LINGER_TIME       2 // s
+
 /****************************************************************************/
 /* Socket API Signatures                                                    */
 /****************************************************************************/
@@ -281,6 +290,8 @@ int zts_getpeername(ZT_GETPEERNAME_SIG);
 
 /**
  * Close a socket
+ * TODO: Check that closing a socket immediately after writing doesn't behave in 
+ * an undefined manner
  */
 int zts_close(ZT_CLOSE_SIG);