io.pkts.packet.sctp

Interface SctpDataChunk

All Superinterfaces:

SctpChunk

All Known Implementing Classes:

SctpDataChunkImpl

public interface SctpDataChunk
extends SctpChunk

Nested Class Summary

Nested classes/interfaces inherited from interface io.pkts.packet.sctp.SctpChunk

SctpChunk.Type

Method Summary

Modifier and Type	Method and Description
long	getPayloadProtocolIdentifier() This value represents an application (or upper layer) specified protocol identifier.
int	getStreamIdentifier() Identifies the stream to which the following user data belongs.
int	getStreamSequenceNumber() This value represents the Stream Sequence Number of the following user data within the stream S.
long	getTransmissionSequenceNumber() This value represents the TSN for this DATA chunk.
default SctpChunk.Type	getType()
Buffer	getUserData() The actual payload of the data chunk.
boolean	isBeginningFragment() Flag: B bit
boolean	isEndingFragment() Flag: E bit
boolean	isImmediate() Flag: I bit
boolean	isUnordered() Flag: U bit

Methods inherited from interface io.pkts.packet.sctp.SctpChunk

frame, getFlags, getHeader, getLength, getPadding, getValue, getValueLength, lookup

Method Detail

isUnordered

boolean isUnordered()

Flag: U bit

The (U)nordered bit, if set to '1', indicates that this is an unordered DATA chunk, and there is no Stream Sequence Number assigned to this DATA chunk. Therefore, the receiver MUST ignore the Stream Sequence Number field.

After reassembly (if necessary), unordered DATA chunks MUST be dispatched to the upper layer by the receiver without any attempt to reorder.

If an unordered user message is fragmented, each fragment of the message MUST have its U bit set to '1'.

(source: RFC 4960 Section 3.3.1)

Returns:

isBeginningFragment

boolean isBeginningFragment()

Flag: B bit

(source: RFC 4960 Section 3.3.1)

Returns:

isEndingFragment

boolean isEndingFragment()

Flag: E bit

The (E)nding fragment bit, if set, indicates the last fragment of a user message.

An unfragmented user message shall have both the B and E bits set to '1'. Setting both B and E bits to '0' indicates a middle fragment of a multi-fragment user message, as summarized in the following table:

     B E                  Description
 ============================================================
 |  1 0 | First piece of a fragmented user message          |
 +----------------------------------------------------------+
 |  0 0 | Middle piece of a fragmented user message         |
 +----------------------------------------------------------+
 |  0 1 | Last piece of a fragmented user message           |
 +----------------------------------------------------------+
 |  1 1 | Unfragmented message                              |
 ============================================================
 |             Table 1: Fragment Description Flags          |
 ============================================================
 

When a user message is fragmented into multiple chunks, the TSNs are used by the receiver to reassemble the message. This means that the TSNs for each fragment of a fragmented user message MUST be strictly sequential. (source: RFC 4960 Section 3.3.1)

Returns:

isImmediate

boolean isImmediate()

Flag: I bit

By setting this bit, the sender of a DATA chunk indicates that the corresponding SACK chunk should not be delayed.

(source: RFC 7053 Section 3)

getTransmissionSequenceNumber

long getTransmissionSequenceNumber()

This value represents the TSN for this DATA chunk. The valid range of TSN is from 0 to 4294967295 (2**32 - 1). TSN wraps back to 0 after reaching 4294967295.

(source: RFC 4960 Section 3.3.1)

getStreamIdentifier

int getStreamIdentifier()

Identifies the stream to which the following user data belongs.

(source: RFC 4960 Section 3.3.1)

getStreamSequenceNumber

int getStreamSequenceNumber()

This value represents the Stream Sequence Number of the following user data within the stream S. Valid range is 0 to 65535.

When a user message is fragmented by SCTP for transport, the same Stream Sequence Number MUST be carried in each of the fragments of the message.

(source: RFC 4960 Section 3.3.1)

getPayloadProtocolIdentifier

long getPayloadProtocolIdentifier()

This value represents an application (or upper layer) specified protocol identifier. This value is passed to SCTP by its upper layer and sent to its peer. This identifier is not used by SCTP but can be used by certain network entities, as well as by the peer application, to identify the type of information being carried in this DATA chunk. This field must be sent even in fragmented DATA chunks (to make sure it is available for agents in the middle of the network). Note that this field is NOT touched by an SCTP implementation; therefore, its byte order is NOT necessarily big endian. The upper layer is responsible for any byte order conversions to this field.

The value 0 indicates that no application identifier is specified by the upper layer for this payload data.

(source: RFC 4960 Section 3.3.1)

getUserData

Buffer getUserData()

The actual payload of the data chunk. The returned buffer will not contain any potential padding.

getType

default SctpChunk.Type getType()

Specified by:

getType in interface SctpChunk