SSU packet size

SSUData.cpp

@@ -245,7 +245,7 @@ namespace ssu
 		sentMessage->numResends = 0;
 		auto& fragments = sentMessage->fragments;
 		msgID = htobe32 (msgID);	
-		size_t payloadSize = SSU_MTU - sizeof (SSUHeader) - 9; // 9  =  flag + #frg(1) + messageID(4) + frag info (3) 
+		size_t payloadSize = SSU_PACKET_SIZE - sizeof (SSUHeader) - 9; // 9  =  flag + #frg(1) + messageID(4) + frag info (3) 
 		size_t len = msg->GetLength ();
 		uint8_t * msgBuf = msg->GetSSUHeader ();
 

SSUData.h

@@ -14,7 +14,8 @@ namespace i2p
 namespace ssu
 {
 
-	const size_t SSU_MTU = 1472; // 1484;
+	const size_t SSU_MTU = 1484;
+	const size_t SSU_PACKET_SIZE = SSU_MTU - 20 - 8; // 20 - IPv4 header, 8 - UDP
 	const int RESEND_INTERVAL = 3; // in seconds
 	const int MAX_NUM_RESENDS = 5;
 	// data flags
@@ -30,7 +31,7 @@ namespace ssu
 		int fragmentNum;
 		size_t len;
 		bool isLast;
-		uint8_t buf[SSU_MTU + 18];
+		uint8_t buf[SSU_PACKET_SIZE + 18];
 
 		Fragment () = default;
 		Fragment (int n, const uint8_t * b, int l, bool last):