Method Details

• processPayload

  public static int processPayload(I2PAppContext ctx, SSU2Payload.PayloadCallback cb, byte[] payload, int off, int length, boolean isHandshake, RemoteHostId from) throws IOException, DataFormatException, I2NPMessageException

  Incoming payload. Calls the callback for each received block.

  Parameters:

  ctx - the application context

  cb - called once per received block

  payload - buffer holding the payload

  off - offset in payload of the first byte

  length - number of bytes to read

  isHandshake - true for Token Req, Retry, Sess Req, Sess Created; false for Sess Confirmed

  from - for path challenge/response only, may be null

  Returns:

  number of blocks processed

  Throws:

  IOException - on major errors

  DataFormatException - on parsing of individual blocks

  I2NPMessageException - on parsing of I2NP block

• checkBlockOrder

  static void checkBlockOrder(int type, boolean gotPadding, boolean gotTermination, boolean isHandshake, int blocks) throws IOException

  Order-rule guard for the incoming-block scan. Padding must terminate the block list; only padding may follow a termination block; a handshake must start with a DATETIME block. Each violation is a protocol error, thrown as an IOException.

  Parameters:

  type - the current block type byte

  gotPadding - true if a BLOCK_PADDING preceded this block

  gotTermination - true if a BLOCK_TERMINATION preceded this block

  isHandshake - true if this is a handshake frame, where the first block must be DATETIME

  blocks - the number of blocks processed before this one

  Throws:

  IOException - on any ordering violation

• checkHandshakeNotEmpty

  static void checkHandshakeNotEmpty(boolean isHandshake, int blocks) throws IOException

  Guard that a handshake frame carries at least one block.

  Parameters:

  isHandshake - true if this is a handshake frame

  blocks - the total number of blocks processed in the frame

  Throws:

  IOException - if the frame is a handshake with no blocks

• checkFrameOverflow

  static void checkFrameOverflow(int off, int length, int dataOff, int len, int blocks, int type) throws IOException

  Guard that a block's declared length fits inside the frame. Offsets in the error message are byte positions relative to the frame. The frame contents are deliberately not included, they may be decrypted data. Callers that want a dump log it at DEBUG.

  Parameters:

  off - start of the payload in the array

  length - frame size in bytes

  dataOff - offset of the block's 2-byte length field

  len - the declared block length

  blocks - the zero-based index of this block for the error message

  type - the block type byte for the error message

  Throws:

  IOException - if the block runs past the end of the frame

• parseDateTime

  static void parseDateTime(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len) throws IOException, DataFormatException

  Parse a DATETIME block of exactly 4 bytes.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be 4

  Throws:

  IOException - on bad length

  DataFormatException - if the callback rejects the timestamp

• parseOptions

  static void parseOptions(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake) throws DataFormatException

  Parse an OPTIONS block, copying the option bytes for the callback.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length

  isHandshake - passed through to the callback

  Throws:

  DataFormatException - if the callback rejects the options

• parseRouterInfo

  static void parseRouterInfo(I2PAppContext ctx, SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake) throws IOException, DataFormatException

  Parse a ROUTERINFO block: one- or two-byte header, then either a single (possibly compressed) RouterInfo or a fragment piece.

  Parameters:

  ctx - context for decompression and logging

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be > 1

  isHandshake - passed through to the callback

  Throws:

  IOException - on framing errors

  DataFormatException - if the RouterInfo is too large or fails verification

• parseRouterInfoSingle

  static RouterInfo parseRouterInfoSingle(I2PAppContext ctx, ByteArrayInputStream bais) throws IOException, DataFormatException

  Read a complete RouterInfo from the stream, falling back to an alternate signature verification when the strict parse fails.

  Parameters:

  ctx - context for logging

  bais - the RI bytes, positioned at the start

  Returns:

  the parsed RouterInfo (possibly a partially filled-in one, signalled by RouterInfo.setPublished(long) of -1)

  Throws:

  IOException - on any I/O while reading the stream

  DataFormatException - on a genuinely malformed RI that fails the alternate verification

• recoverRouterInfo

  static RouterInfo recoverRouterInfo(I2PAppContext ctx, ByteArrayInputStream bais, DataFormatException dfe) throws IOException, DataFormatException

  Alternate verification of a RouterInfo whose strict parse failed: if the signed prefix is valid, return a partially filled-in RI (published = -1) so the session layer can still act on the identity.

  Parameters:

  ctx - context for logging

  bais - the RI bytes; position is reset for re-reading identity and signature

  dfe - the original parse failure

  Returns:

  a partially filled-in RouterInfo when the signature verifies

  Throws:

  IOException - on any I/O while re-reading the stream

  DataFormatException - the original parse failure when verification fails

• parseI2NP

  static void parseI2NP(I2PAppContext ctx, SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake) throws IOException, I2NPMessageException

  Parse an I2NP block (data blocks only, never in handshakes).

  Parameters:

  ctx - context for I2NP parsing

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be ≥ 9

  isHandshake - if true the block is illegal

  Throws:

  IOException - if the block appears in a handshake or is too short

  I2NPMessageException - if the embedded I2NP message is malformed

• parseFirstFragment

  static void parseFirstFragment(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake) throws IOException, DataFormatException

  Parse the first fragment of a fragmented message (data blocks only). The 1-byte flag and 4-byte message ID precede the fragment data; the callback receives the raw payload slice.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be > 9

  isHandshake - if true the block is illegal

  Throws:

  IOException - if the block appears in a handshake or is too short

  DataFormatException - if the callback rejects the fragment

• parseFollowonFragment

  static void parseFollowonFragment(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake) throws IOException, DataFormatException

  Parse a follow-on fragment block (data blocks only). The low bit of the flag byte marks the last fragment; the remaining bits carry the fragment number.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be > 5

  isHandshake - if true the block is illegal

  Throws:

  IOException - if the block appears in a handshake, is too short, or has fragment number 0

  DataFormatException - if the callback rejects the fragment

• parseACK

  static void parseACK(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake) throws IOException

  Parse an ACK block (data blocks only). Odd block length: 4-byte ack ID, 1-byte fragment count, then the ACK range bitmap (possibly zero length).

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be ≥ 5 and odd

  isHandshake - if true the block is illegal

  Throws:

  IOException - if the block appears in a handshake or has a bad length

• parseAddress

  static void parseAddress(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len) throws IOException

  Parse an ADDRESS block of 4 bytes IPv4 or 16 bytes IPv6.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be 6 or 18

  Throws:

  IOException - on bad length

• parseRelayTag

  static void parseRelayTag(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len) throws IOException

  Parse a RELAYTAG block of at least 4 bytes.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be ≥ 4

  Throws:

  IOException - on bad length

• parseRelayRequest

  static void parseRelayRequest(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake) throws IOException

  Parse a RELAYREQ block (data blocks only): 1 flag byte then the relay request (IPv4 address + DSA signature).

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be ≥ 61

  isHandshake - if true the block is illegal

  Throws:

  IOException - if the block appears in a handshake or is too short

• parseRelayResponse

  static void parseRelayResponse(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake) throws IOException

  Parse a RELAYRESP block (data blocks only): 1 flag byte, 1 response code byte, and the remaining response data.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be ≥ 52

  isHandshake - if true the block is illegal

  Throws:

  IOException - if the block appears in a handshake or is too short

• parseRelayIntro

  static void parseRelayIntro(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake) throws IOException

  Parse a RELAYINTRO block (data blocks only): 1 flag byte, the 32-byte introducer hash, then the intro data.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be ≥ 93

  isHandshake - if true the block is illegal

  Throws:

  IOException - if the block appears in a handshake or is too short

• parsePeerTest

  static void parsePeerTest(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake) throws IOException, DataFormatException

  Parse a PEERTEST block (data blocks only): message number, response code, an optional 32-byte hash for questions 2/4, and the data payload.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be ≥ 19

  isHandshake - if true the block is illegal

  Throws:

  IOException - if the block appears in a handshake or is too short

  DataFormatException - if the message number is out of the 1-7 range

• parseNewToken

  static void parseNewToken(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len) throws IOException

  Parse a NEWTOKEN block of at least 12 bytes: 4-byte expiry, 8-byte token.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be ≥ 12

  Throws:

  IOException - on bad length

• parseTermination

  static void parseTermination(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len) throws IOException

  Parse a TERMINATION block of at least 9 bytes: 8-byte receive time, 1 byte reason code. The caller must flag the frame as terminated.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length, must be ≥ 9

  Throws:

  IOException - on bad length

• parsePathChallenge

  static void parsePathChallenge(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake, RemoteHostId from) throws IOException

  Parse a PATHCHALLENGE block (data blocks only), passing the challenge array up with the originating address.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length

  isHandshake - if true the block is illegal

  from - the originating address, may be null

  Throws:

  IOException - if the block appears in a handshake

• parsePathResponse

  static void parsePathResponse(SSU2Payload.PayloadCallback cb, byte[] payload, int i, int len, boolean isHandshake, RemoteHostId from) throws IOException

  Parse a PATHRESP block (data blocks only), passing the response array up with the originating address.

  Parameters:

  cb - callback

  payload - the whole frame

  i - offset of the block data

  len - declared block length

  isHandshake - if true the block is illegal

  from - the originating address, may be null

  Throws:

  IOException - if the block appears in a handshake

• parseUnknown

  static void parseUnknown(I2PAppContext ctx, SSU2Payload.PayloadCallback cb, int type, int len)

  Unknown block type: warn once per occurrence and skip the block.

  Parameters:

  ctx - context for logging

  cb - callback, included in the message for context

  type - the unknown block type byte

  len - the declared block length

• writePayload

  public static int writePayload(byte[] payload, int off, List<SSU2Payload.Block> blocks)

  Serialize a list of blocks into a payload.

  Parameters:

  payload - writes to it starting at off

  off - offset in payload to start writing at

  blocks - the blocks to write, in order

  Returns:

  the new offset