Class PacketBuilder

Method Details

• getMaxAdditionalFragmentSize

  public static int getMaxAdditionalFragmentSize​(PeerState peer, int numFragments, int curDataSize)

  Will a packet to 'peer' that already has 'numFragments' fragments totalling 'curDataSize' bytes fit another fragment of size 'newFragSize' ?? This doesn't leave anything for acks.

  Parameters:

  numFragments - >= 1

  Since:

  0.9.16

• buildPacket

  public UDPPacket buildPacket​(OutboundMessageState state, int fragment, PeerState peer, Collection<Long> ackIdsRemaining, int newAckCount, List<ACKBitfield> partialACKsRemaining)

  This builds a data packet (PAYLOAD_TYPE_DATA). See the methods below for the other message types. Note that while the UDP message spec allows for more than one fragment in a message, this method writes exactly one fragment. For no fragments use buildAck(). Multiple fragments in a single packet is not supported. Rekeying and extended options are not supported. Packet format:

      16 byte MAC
      16 byte IV
       1 byte flag
       4 byte date
       1 byte flag
       1 byte explicit ack count IF included
     4*n byte explict acks IF included
       1 byte ack bitfield count IF included
     4*n + ?? ack bitfields IF included
       1 byte fragment count (always 1)
       4 byte message ID
       3 byte fragment info
       n byte fragment
    0-15 bytes padding
  

  So ignoring the ack bitfields, and assuming we have explicit acks, it's (47 + 4*explict acks + padding) added to the fragment length.

  Parameters:

  ackIdsRemaining - list of messageIds (Long) that should be acked by this packet. The list itself is passed by reference, and if a messageId is transmitted it will be removed from the list. Not all message IDs will necessarily be sent, there may not be room. non-null.

  newAckCount - the number of ackIdsRemaining entries that are new. These must be the first ones in the list

  partialACKsRemaining - list of messageIds (ACKBitfield) that should be acked by this packet. The list itself is passed by reference, and if a messageId is included, it should be removed from the list. Full acks in this list are skipped, they are NOT transmitted. non-null. Not all acks will necessarily be sent, there may not be room.

  Returns:

  null on error

• buildPacket

  public UDPPacket buildPacket​(List<PacketBuilder.Fragment> fragments, PeerState peer, Collection<Long> ackIdsRemaining, int newAckCount, List<ACKBitfield> partialACKsRemaining)

• buildPing

  public UDPPacket buildPing​(PeerState peer)

  An ACK packet with no acks. We use this for keepalive purposes. It doesn't generate a reply, but that's ok.

• buildACK

  public UDPPacket buildACK​(PeerState peer, List<ACKBitfield> ackBitfields)

  Build the ack packet. The list need not be sorted into full and partial; this method will put all fulls before the partials in the outgoing packet. An ack packet is just a data packet with no data. See buildPacket() for format. TODO MTU not enforced. TODO handle huge number of acks better

  Parameters:

  ackBitfields - list of ACKBitfield instances to either fully or partially ACK

• buildSessionCreatedPacket

  public UDPPacket buildSessionCreatedPacket​(InboundEstablishState state, int externalPort, SessionKey ourIntroKey)

  Build a new SessionCreated packet for the given peer, encrypting it as necessary.

  Returns:

  ready to send packet, or null if there was a problem

• buildSessionRequestPacket

  public UDPPacket buildSessionRequestPacket​(OutboundEstablishState state)

  Build a new SessionRequest packet for the given peer, encrypting it as necessary.

  Returns:

  ready to send packet, or null if there was a problem

• buildSessionConfirmedPackets

  public UDPPacket[] buildSessionConfirmedPackets​(OutboundEstablishState state, RouterIdentity ourIdentity)

  Build a new series of SessionConfirmed packets for the given peer, encrypting it as necessary. Note that while a SessionConfirmed could in theory be fragmented, in practice a RouterIdentity is 387 bytes and a single fragment is 512 bytes max, so it will never be fragmented.

  Returns:

  ready to send packets, or null if there was a problem TODO: doesn't really return null, and caller doesn't handle null return (null SigningPrivateKey should cause this?) Should probably return null if buildSessionConfirmedPacket() returns null for any fragment

• buildSessionDestroyPacket

  public UDPPacket buildSessionDestroyPacket​(PeerState peer)

  Build a destroy packet, which contains a header but no body. Session must be established or this will NPE in authenticate(). Unused until 0.8.9.

  Since:

  0.8.1

• buildSessionDestroyPacket

  public UDPPacket buildSessionDestroyPacket​(OutboundEstablishState peer)

  Build a destroy packet, which contains a header but no body. If the keys and ip/port are not yet set, this will return null.

  Returns:

  packet or null

  Since:

  0.9.2

• buildSessionDestroyPacket

  public UDPPacket buildSessionDestroyPacket​(InboundEstablishState peer)

  Build a destroy packet, which contains a header but no body. If the keys and ip/port are not yet set, this will return null.

  Returns:

  packet or null

  Since:

  0.9.2

• buildPeerTestFromAlice

  public UDPPacket buildPeerTestFromAlice​(InetAddress toIP, int toPort, SessionKey toIntroKey, long nonce, SessionKey aliceIntroKey)

  Build a packet as if we are Alice and we either want Bob to begin a peer test or Charlie to finish a peer test.

  Returns:

  ready to send packet, or null if there was a problem

• buildPeerTestFromAlice

  public UDPPacket buildPeerTestFromAlice​(InetAddress toIP, int toPort, SessionKey toCipherKey, SessionKey toMACKey, long nonce, SessionKey aliceIntroKey)

  Build a packet as if we are Alice and we either want Bob to begin a peer test or Charlie to finish a peer test.

  Returns:

  ready to send packet, or null if there was a problem

• buildPeerTestToAlice

  public UDPPacket buildPeerTestToAlice​(InetAddress aliceIP, int alicePort, SessionKey aliceIntroKey, SessionKey charlieIntroKey, long nonce)

  Build a packet as if we are either Bob or Charlie and we are helping test Alice.

  Returns:

  ready to send packet, or null if there was a problem

• buildPeerTestToCharlie

  public UDPPacket buildPeerTestToCharlie​(InetAddress aliceIP, int alicePort, SessionKey aliceIntroKey, long nonce, InetAddress charlieIP, int charliePort, SessionKey charlieCipherKey, SessionKey charlieMACKey)

  Build a packet as if we are Bob sending Charlie a packet to help test Alice.

  Returns:

  ready to send packet, or null if there was a problem

• buildPeerTestToBob

  public UDPPacket buildPeerTestToBob​(InetAddress bobIP, int bobPort, InetAddress aliceIP, int alicePort, SessionKey aliceIntroKey, long nonce, SessionKey bobCipherKey, SessionKey bobMACKey)

  Build a packet as if we are Charlie sending Bob a packet verifying that we will help test Alice.

  Returns:

  ready to send packet, or null if there was a problem

• buildRelayRequest

  public List<UDPPacket> buildRelayRequest​(UDPTransport transport, EstablishmentManager emgr, OutboundEstablishState state, SessionKey ourIntroKey)

  build intro packets for each of the published introducers

  Parameters:

  emgr - only to call emgr.isValid()

  Returns:

  empty list on failure

• buildRelayIntro

  UDPPacket buildRelayIntro​(RemoteHostId alice, PeerState charlie, UDPPacketReader.RelayRequestReader request)

• buildRelayResponse

  UDPPacket buildRelayResponse​(RemoteHostId alice, PeerState charlie, long nonce, SessionKey cipherKey, SessionKey macKey)

• buildHolePunch

  public UDPPacket buildHolePunch​(InetAddress to, int port)

  Creates an empty unauthenticated packet for hole punching. Parameters must be validated previously.

• buildPacket

  public UDPPacket buildPacket​(byte[] data, InetAddress to, int port)

  TESTING ONLY. Creates an arbitrary packet for unit testing. Null transport in constructor OK.

  Since:

  IPv6