Added service hash for resolving port/protocol numbers to names.

Minor fix to handling of netmasks end /32.

serv_hash.h

@@ -0,0 +1,22 @@
+/*
+ * addr_hash.h:
+ *
+ */
+
+#ifndef __SERV_HASH_H_ /* include guard */
+#define __SERV_HASH_H_
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include "hash.h"
+
+typedef struct {
+    int port;
+    int protocol;
+} ip_service; 
+
+hash_type* serv_hash_create();
+void serv_hash_initialise(hash_type* sh);
+
+#endif /* __SERV_HASH_H_ */