Don't use reversed port for choise random port. (by whothefuckami)

libi2pd/RouterContext.cpp

@@ -202,7 +202,13 @@ namespace i2p
 
 	uint16_t RouterContext::SelectRandomPort () const
 	{
-		uint16_t port = rand () % (30777 - 9111) + 9111; // I2P network ports range
+		uint16_t port;
+		do
+        {
+            port = rand () % (30777 - 9111) + 9111; // I2P network ports range
+        }
+        while(i2p::util::net::IsPortInReservedRange(port));
+
 		if (port == 9150) port = 9151; // Tor browser
 		return port;
 	}

libi2pd/util.cpp

@@ -8,6 +8,7 @@
 
 #include <cstdlib>
 #include <string>
+#include <unordered_set>
 #include <boost/asio.hpp>
 
 #include "util.h"
@@ -487,6 +488,21 @@ namespace net
 		return IsYggdrasilAddress (addr.to_v6 ().to_bytes ().data ());
 	}
 
+    bool IsPortInReservedRange (const uint16_t port) noexcept
+    {
+        static const std::unordered_set<uint16_t> reservedPorts{
+            9119,9306,9312,9389,9418,9535,9536,9695,
+            9800,9899,10000,10050,10051,10110,10212,
+            10933,11001,11112,11235,11371,12222,12223,
+            13075,13400,13720,13721,13724,13782,13783,
+            13785,13786,15345,17224,17225,17500,18104,
+            19788,19812,19813,19814,19999,20000,24465,
+            24554,26000,27000,27001,27002,27003,27004,
+            27005,27006,27007,27008,27009,28000};
+
+        return (reservedPorts.find(port) != reservedPorts.end());
+    }
+
 	boost::asio::ip::address_v6 GetYggdrasilAddress ()
 	{
 #if defined(_WIN32)

libi2pd/util.h

@@ -224,6 +224,7 @@ namespace util
 		bool IsLocalAddress (const boost::asio::ip::address& addr);
 		bool IsInReservedRange (const boost::asio::ip::address& host);
 		bool IsYggdrasilAddress (const boost::asio::ip::address& addr);
+        bool IsPortInReservedRange (const uint16_t port) noexcept;
 	}
 }
 }