/**
* Returns the ip (given in BIG-endian) format of buf[offset]...buf[offset+3] as standard
* dotted-decimal, e.g., 192.168.0.1
*
* <p>
*
* @param ip the IP address to convert
* @param offset the offset into the IP array to convert
* @return the IP address as a dotted-quad string
*/
public static final String ip2string(byte[] ip, int offset) {
// xxx.xxx.xxx.xxx => 15 chars
StringBuffer sbuf = new StringBuffer(16);
sbuf.append(ByteOrder.ubyte2int(ip[offset]));
sbuf.append('.');
sbuf.append(ByteOrder.ubyte2int(ip[offset + 1]));
sbuf.append('.');
sbuf.append(ByteOrder.ubyte2int(ip[offset + 2]));
sbuf.append('.');
sbuf.append(ByteOrder.ubyte2int(ip[offset + 3]));
return sbuf.toString();
}
/**
* Make a new PatchTableMessage object by parsing data a remote computer sent us.
*
* <p>Creates a new PATCH variant with data read from the network. The first byte is guaranteed to
* be PATCH_VARIANT.
*
* <p>Throws BadPacketException the remaining values in payload are not well-formed, e.g., because
* it's the wrong length, the sequence size is less than the sequence number, etc.
*
* @param guid The message GUID we read from the header
* @param ttl The TTL we read from the message header
* @param hops The hops count we read from the message header
* @param payload The payload of the message after that, like fNSCBpatchdatapatchdatapatchdata
*/
protected PatchTableMessage(byte[] guid, byte ttl, byte hops, byte[] payload)
throws BadPacketException {
// Save the GUID, TTL, hops and length in the Message and RouteTableMessage cores of this new
// PatchTableMessage
super(
guid,
ttl,
hops,
payload.length,
RouteTableMessage.PATCH_VARIANT); // 0x01 identifies this as a PatchTableMessage
/*
* TODO: maybe we shouldn't enforce this
* if (payload.length < 5) throw new BadPacketException("Extra arguments in reset message.");
*/
/*
* The payload of a patch message looks like this:
*
* fNSCBpatchdatapatchdata...
*/
// Make sure the first payload byte, f, is 0x01, identifying this as a patch message
Assert.that(payload[0] == PATCH_VARIANT);
// Read the sequence number and sequence size, N and S, a distance of 1 and 2 bytes into the
// payload data
this.sequenceNumber = (short) ByteOrder.ubyte2int(payload[1]);
this.sequenceSize = (short) ByteOrder.ubyte2int(payload[2]);
if (sequenceNumber < 1 || sequenceSize < 1 || sequenceNumber > sequenceSize)
throw new BadPacketException("Bad sequence/size: " + sequenceNumber + "/" + sequenceSize);
// Find out if the patch data is compressed by reading C 3 bytes into the payload data
this.compressor = payload[3];
if (!(compressor == COMPRESSOR_NONE || compressor == COMPRESSOR_DEFLATE))
throw new BadPacketException("Bad compressor: " + compressor);
// Find out if the patch data was halved or not by reading B 4 bytes into the payload data
this.entryBits = payload[4];
if (entryBits < 0) throw new BadPacketException("Negative entryBits: " + entryBits);
// Clip out the chunk of probably compressed and halved patch data this patch message carries
// after that
this.data =
new byte
[payload.length
- 5]; // It's the whole paylaod not including the first 4 fNSCB bytes we read
System.arraycopy(payload, 5, data, 0, data.length); // Copy it from 5 bytes in to the end
}
