- Add better protection against DoSing connecting users from connecting

- Have Com_sprintf return string length
- add STR_LEN macro for static strings

code/server/server.h

@@ -197,7 +197,11 @@ typedef struct client_s {
 // MAX_CHALLENGES is made large to prevent a denial
 // of service attack that could cycle all of them
 // out before legitimate users connected
-#define	MAX_CHALLENGES	1024
+#define	MAX_CHALLENGES	2048
+// Allow a certain amount of challenges to have the same IP address
+// to make it a bit harder to DOS one single IP address from connecting
+// while not allowing a single ip to grab all challenge resources
+#define MAX_CHALLENGES_MULTI (MAX_CHALLENGES / 2)
 
 #define	AUTHORIZE_TIMEOUT	5000