/**
* Make a new PushRequest object for us to send with the given information. This is the packet
* maker.
*
* @param guid For the header, the message GUID that will mark this packet unique
* @param ttl For the header, the TTL
* @param clientGUID For the payload, the client ID GUID of the firewalled computer that has the
* file and will push open the connection
* @param index For the payload, the ID number the firewalled computer has assigned the file the
* downloading computer wants
* @param ip For the payload, the downloading computer's IP address the firewalled computer will
* push open a connection to
* @param port For the payload, the downloading computer's port number the firewalled computer
* will push open a connection to
* @param network The Internet protocol this push packet will travel on, like 1 N_TCP or 2 N_UDP,
* this is not a part of the packet that's sent
* @return A new PushRequest object with that information
*/
public PushRequest(
byte[] guid, byte ttl, byte[] clientGUID, long index, byte[] ip, int port, int network) {
// Call the Message constructor to save packet header information
super(
guid, // The message GUID
Message.F_PUSH, // 0x40, this is a push message
ttl, // The number of times this push will be able to travel between ultrapeers
(byte) 0, // This push message hasn't traveled any hops yet
STANDARD_PAYLOAD_SIZE, // The payload length will be 26 bytes
network); // The Internet protocol we'll use to send, the Message object keeps this
// information but it is not part of the packet that's sent
// Make sure the GUID is 16 bytes, the file id fits in 4 bytes, the IP is 4 bytes, the IP
// address doesn't start 0 or 255, and the port number fits in 2 bytes
if (clientGUID.length != 16)
throw new IllegalArgumentException("invalid guid length: " + clientGUID.length);
else if ((index & 0xFFFFFFFF00000000l) != 0)
throw new IllegalArgumentException("invalid index: " + index);
else if (ip.length != 4) throw new IllegalArgumentException("invalid ip length: " + ip.length);
else if (!NetworkUtils.isValidAddress(ip))
throw new IllegalArgumentException("invalid ip " + NetworkUtils.ip2string(ip));
else if (!NetworkUtils.isValidPort(port))
throw new IllegalArgumentException("invalid port: " + port);
/*
* The 26 byte pong payload has this structure:
*
* [client ID GUID] At 0, 16 bytes The client ID GUID of the computer that will get this packet and push open a new connection
* FILE At 16, 4 bytes The number the pushing computer has given the file the wanting computer wants
* IPIPPP At 20, 6 bytes The IP address and port number of the wanting computer
*/
// Compose the 26 byte push payload
payload = new byte[STANDARD_PAYLOAD_SIZE]; // Make a byte array that can hold 26 bytes
System.arraycopy(clientGUID, 0, payload, 0, 16); // Copy the client ID GUID into the first 16
ByteOrder.int2leb((int) index, payload, 16); // 16 bytes into the array, copy the 4 byte file id
payload[20] = ip[0]; // 20 bytes into the array, copy the 4 bytes of the IP address
payload[21] = ip[1];
payload[22] = ip[2];
payload[23] = ip[3];
ByteOrder.short2leb(
(short) port, payload, 24); // 24 bytes into the array, place the 2 byte port number
}
