public static NPFPacket create(byte[] plaintext, BasePeerNode pn) {
NPFPacket packet = new NPFPacket();
if (pn == null)
throw new IllegalArgumentException("Can't estimate an ack type of received packet");
int offset = 0;
if (plaintext.length < (offset + 5)) { // Sequence number + the number of acks
packet.error = true;
return packet;
}
packet.sequenceNumber =
((plaintext[offset] & 0xFF) << 24)
| ((plaintext[offset + 1] & 0xFF) << 16)
| ((plaintext[offset + 2] & 0xFF) << 8)
| (plaintext[offset + 3] & 0xFF);
offset += 4;
// Process received acks
int numAckRanges = plaintext[offset++] & 0xFF;
if (numAckRanges > 0) {
try {
int ack, prevAck = 0;
for (int i = 0; i < numAckRanges; i++) {
if (i == 0) {
ack =
((plaintext[offset] & 0xFF) << 24)
| ((plaintext[offset + 1] & 0xFF) << 16)
| ((plaintext[offset + 2] & 0xFF) << 8)
| (plaintext[offset + 3] & 0xFF);
offset += 4;
} else {
int distanceFromPrevious = (plaintext[offset++] & 0xFF);
if (distanceFromPrevious != 0) {
ack = prevAck + distanceFromPrevious;
} else {
// Far offset
ack =
((plaintext[offset] & 0xFF) << 24)
| ((plaintext[offset + 1] & 0xFF) << 16)
| ((plaintext[offset + 2] & 0xFF) << 8)
| (plaintext[offset + 3] & 0xFF);
offset += 4;
}
}
int rangeSize = (plaintext[offset++] & 0xFF);
for (int j = 1; j <= rangeSize; j++) {
packet.acks.add(ack++);
}
prevAck = ack - 1;
}
} catch (ArrayIndexOutOfBoundsException e) {
// The packet's length is not big enough
packet.error = true;
return packet;
}
}
// Handle received message fragments
int prevFragmentID = -1;
while (offset < plaintext.length) {
boolean shortMessage = (plaintext[offset] & 0x80) != 0;
boolean isFragmented = (plaintext[offset] & 0x40) != 0;
boolean firstFragment = (plaintext[offset] & 0x20) != 0;
if (!isFragmented && !firstFragment) {
// Padding or lossy messages.
offset = tryParseLossyMessages(packet, plaintext, offset);
break;
}
int messageID = -1;
if ((plaintext[offset] & 0x10) != 0) {
if (plaintext.length < (offset + 4)) {
packet.error = true;
return packet;
}
messageID =
((plaintext[offset] & 0x0F) << 24)
| ((plaintext[offset + 1] & 0xFF) << 16)
| ((plaintext[offset + 2] & 0xFF) << 8)
| (plaintext[offset + 3] & 0xFF);
offset += 4;
} else {
if (plaintext.length < (offset + 2)) {
packet.error = true;
return packet;
}
if (prevFragmentID == -1) {
Logger.warning(NPFPacket.class, "First fragment doesn't have full message id");
packet.error = true;
return packet;
}
messageID =
prevFragmentID + (((plaintext[offset] & 0x0F) << 8) | (plaintext[offset + 1] & 0xFF));
offset += 2;
}
prevFragmentID = messageID;
int requiredLength =
offset + (shortMessage ? 1 : 2) + (isFragmented ? (shortMessage ? 1 : 3) : 0);
if (plaintext.length < requiredLength) {
packet.error = true;
return packet;
}
int fragmentLength;
if (shortMessage) {
fragmentLength = plaintext[offset++] & 0xFF;
} else {
fragmentLength = ((plaintext[offset] & 0xFF) << 8) | (plaintext[offset + 1] & 0xFF);
offset += 2;
}
int messageLength = -1;
int fragmentOffset = 0;
if (isFragmented) {
int value;
if (shortMessage) {
value = plaintext[offset++] & 0xFF;
} else {
value = ((plaintext[offset] & 0xFF) << 8) | (plaintext[offset + 1] & 0xFF);
offset += 2;
}
if (firstFragment) {
messageLength = value;
if (messageLength == fragmentLength) {
Logger.warning(
NPFPacket.class,
"Received fragmented message, but fragment contains the entire message");
}
} else {
fragmentOffset = value;
}
} else {
messageLength = fragmentLength;
}
if ((offset + fragmentLength) > plaintext.length) {
Logger.error(
NPFPacket.class,
"Fragment doesn't fit in the received packet: offset is "
+ offset
+ " fragment length is "
+ fragmentLength
+ " plaintext length is "
+ plaintext.length
+ " message length "
+ messageLength
+ " message ID "
+ messageID
+ (pn == null ? "" : (" from " + pn.shortToString())));
packet.error = true;
break;
}
byte[] fragmentData = Arrays.copyOfRange(plaintext, offset, offset + fragmentLength);
offset += fragmentLength;
packet.fragments.add(
new MessageFragment(
shortMessage,
isFragmented,
firstFragment,
messageID,
fragmentLength,
messageLength,
fragmentOffset,
fragmentData,
null));
}
packet.length = offset;
return packet;
}
public static NPFPacket create(byte[] plaintext, BasePeerNode pn) {
NPFPacket packet = new NPFPacket();
int offset = 0;
if (plaintext.length < (offset + 5)) { // Sequence number + the number of acks
packet.error = true;
return packet;
}
packet.sequenceNumber =
((plaintext[offset] & 0xFF) << 24)
| ((plaintext[offset + 1] & 0xFF) << 16)
| ((plaintext[offset + 2] & 0xFF) << 8)
| (plaintext[offset + 3] & 0xFF);
offset += 4;
// Process received acks
int numAcks = plaintext[offset++] & 0xFF;
if (plaintext.length < (offset + numAcks + (numAcks > 0 ? 3 : 0))) {
packet.error = true;
return packet;
}
int prevAck = 0;
for (int i = 0; i < numAcks; i++) {
int ack = 0;
if (i == 0) {
ack =
((plaintext[offset] & 0xFF) << 24)
| ((plaintext[offset + 1] & 0xFF) << 16)
| ((plaintext[offset + 2] & 0xFF) << 8)
| (plaintext[offset + 3] & 0xFF);
offset += 4;
} else {
ack = prevAck + (plaintext[offset++] & 0xFF);
}
packet.acks.add(ack);
prevAck = ack;
}
// Handle received message fragments
int prevFragmentID = -1;
while (offset < plaintext.length) {
boolean shortMessage = (plaintext[offset] & 0x80) != 0;
boolean isFragmented = (plaintext[offset] & 0x40) != 0;
boolean firstFragment = (plaintext[offset] & 0x20) != 0;
if (!isFragmented && !firstFragment) {
// Padding or lossy messages.
offset = tryParseLossyMessages(packet, plaintext, offset);
break;
}
int messageID = -1;
if ((plaintext[offset] & 0x10) != 0) {
if (plaintext.length < (offset + 4)) {
packet.error = true;
return packet;
}
messageID =
((plaintext[offset] & 0x0F) << 24)
| ((plaintext[offset + 1] & 0xFF) << 16)
| ((plaintext[offset + 2] & 0xFF) << 8)
| (plaintext[offset + 3] & 0xFF);
offset += 4;
} else {
if (plaintext.length < (offset + 2)) {
packet.error = true;
return packet;
}
if (prevFragmentID == -1) {
Logger.warning(NPFPacket.class, "First fragment doesn't have full message id");
packet.error = true;
return packet;
}
messageID =
prevFragmentID + (((plaintext[offset] & 0x0F) << 8) | (plaintext[offset + 1] & 0xFF));
offset += 2;
}
prevFragmentID = messageID;
int requiredLength =
offset + (shortMessage ? 1 : 2) + (isFragmented ? (shortMessage ? 1 : 3) : 0);
if (plaintext.length < requiredLength) {
packet.error = true;
return packet;
}
int fragmentLength;
if (shortMessage) {
fragmentLength = plaintext[offset++] & 0xFF;
} else {
fragmentLength = ((plaintext[offset] & 0xFF) << 8) | (plaintext[offset + 1] & 0xFF);
offset += 2;
}
int messageLength = -1;
int fragmentOffset = 0;
if (isFragmented) {
int value;
if (shortMessage) {
value = plaintext[offset++] & 0xFF;
} else {
value = ((plaintext[offset] & 0xFF) << 8) | (plaintext[offset + 1] & 0xFF);
offset += 2;
}
if (firstFragment) {
messageLength = value;
if (messageLength == fragmentLength) {
Logger.warning(
NPFPacket.class,
"Received fragmented message, but fragment contains the entire message");
}
} else {
fragmentOffset = value;
}
} else {
messageLength = fragmentLength;
}
byte[] fragmentData = new byte[fragmentLength];
if ((offset + fragmentLength) > plaintext.length) {
Logger.error(
NPFPacket.class,
"Fragment doesn't fit in the received packet: offset is "
+ offset
+ " fragment length is "
+ fragmentLength
+ " plaintext length is "
+ plaintext.length
+ " message length "
+ messageLength
+ " message ID "
+ messageID
+ (pn == null ? "" : (" from " + pn.shortToString())));
packet.error = true;
break;
}
System.arraycopy(plaintext, offset, fragmentData, 0, fragmentLength);
offset += fragmentLength;
packet.fragments.add(
new MessageFragment(
shortMessage,
isFragmented,
firstFragment,
messageID,
fragmentLength,
messageLength,
fragmentOffset,
fragmentData,
null));
}
packet.length = offset;
return packet;
}