Package org.ka2ddo.ax25

Class AX25Frame

java.lang.Object
org.ka2ddo.ax25.AX25Frame
All Implemented Interfaces:
Serializable, Comparable<AX25Frame>, AX25FrameSource
public class AX25Frame extends Object implements Serializable, AX25FrameSource, Comparable<AX25Frame>
This class defines 1 AX.25 packet, as defined by the AX.25 Link Level Protocol specification, version 2.2. Note that the Comparable interface is simply sorting by rcptTime.
Version:
2.2
Author:
Andrew Pavlin, KA2DDO
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    byte[]
    body
    Byte array containing the higher-level protocol payload for I and UI frames.
    byte
    ctl
    Bitmask identifying the frame type and subtype, and windowing position for connection-oriented I and S frames.
    byte
    ctl2
    Extension of ctl when using 128-segment windowing.
    AX25Callsign
    dest
    Callsign of the destination station, or some broadcast code with an alternate meaning (such as APRS tocalls and Mic-E encoded latitude and status values).
    AX25Callsign[]
    digipeaters
    Optional array of digipeater callsigns and aliases, if this frame should be digipeated.
    static final int
    FRAMETYPE_I
    Numeric code for information (I) frame type.
    static final int
    FRAMETYPE_S
    Numeric code for supervisory (S) frame type.
    static final int
    FRAMETYPE_U
    Numeric code for unnumbered (U) frame type.
    static final int
    MASK_FRAMETYPE
    The bitmask to extract the frametype bits from the ctl byte of the frame.
    static final int
    MASK_STYPE
    Bitmask to extract supervisory (S) frame subtype from the ctl byte.
    static final int
    MASK_U_P
    Bitmask to extract poll/final bit from unnumbered (U) frame ctl byte, mod 8 format.
    static final int
    MASK_U_P128
    Bitmask to extract poll/final bit from I/S frame 2nd ctl byte, mod 128 format.
    static final int
    MASK_UTYPE
    Bitmask to extract unnumbered (U) frame subtype from the ctl byte.
    boolean
    mod128
    Indicates whether 128-segment windowing is used for I frame connections.
    AX25Message
    parsedAX25Msg
    The decoded APRS (or other protocol) message (if the AX25Frame contains a higher-level protocol).
    byte
    pid
    The one-byte code identifying how to interpret the body of I and UI frames.
    static final byte
    PID_AARP
    Protocol ID for Appletalk Address Resolution Protocol (ARP).
    static final byte
    PID_ATALK
    Protocol ID for Appletalk.
    static final byte
    PID_ESCAPE
    Protocol ID for escape code indicating second byte of PID (not supported).
    static final byte
    PID_FLEXNET
    Protocol ID for FlexNet.
    static final byte
    PID_IARP
    Protocol ID for ARPA Internet Address Resolution Protocol (ARP).
    static final byte
    PID_IP
    Protocol ID for ARPA Internet Protocol.
    static final byte
    PID_LQP
    Protocol ID for Link Quality Protocol.
    static final byte
    PID_NETROM
    Protocol ID for NET/ROM.
    static final byte
    PID_NOLVL3
    Protocol ID for no level 3 protocol (also used for APRS).
    static final byte
    PID_OPENTRAC
    Protocol ID for OpenTRAC.
    static final byte
    PID_SEG_FRAG
    Protocol ID for AX.25 segmentation fragment.
    static final byte
    PID_TEXNET
    Protocol ID for TEXNET datagram.
    static final byte
    PID_VJC_TCPIP
    Protocol ID for Van Jacobson compressed TCP/IP packet, per RFC 1144.
    static final byte
    PID_VJUC_TCPIP
    Protocol ID for Van Jacobson uncompressed TCP/IP packet, per RFC 1144.
    static final byte
    PID_X25_PLP
    Protocol ID for CCITT X.25 PLP (also used by the ROSE network).
    static final Map<Byte,String>
    PTYPES_S
    Hashmap of Information (I) or Unnumbered Information (UI) frame protocol ID to protocol name strings.
    long
    rcptTime
    The time when this message was received in Java milliseconds since midnight, Jan 1 1970 UTC.
    AX25Callsign
    sender
    Callsign of the transmitting station (not of any intermediate digipeaters).
    static final int
    SHIFT_STYPE
    Bit shift to get least significant bit of S frame subtype into least significant bit of integer.
    static final int
    SHIFT_UTYPE
    Bit shift to get least significant bit of U frame subtype into least significant bit of integer.
    Connector
    sourcePort
    Pointer to the I/O port from which this frame was received.
    static final int
    STYPE_REJ
    Unshifted S frame subtype for Reject frame.
    static final int
    STYPE_RNR
    Unshifted S frame subtype for Receive Not Ready frame.
    static final int
    STYPE_RR
    Unshifted S frame subtype for Receive Ready frame.
    static final int
    STYPE_SREJ
    Unshifted S frame subtype for Selective Reject frame.
    static final int
    UTYPE_DISC
    Unshifted U frame subtype for Disconnect (DISC).
    static final int
    UTYPE_DM
    Unshifted U frame subtype for Disconnected Mode (DM).
    static final int
    UTYPE_FRMR
    Deprecated.
    2.0
    static final int
    UTYPE_SABM
    Unshifted U frame subtype for Set Asynchronous Balanced Mode (SABM).
    static final int
    UTYPE_SABME
    Unshifted U frame subtype for Set Asynchronous Balanced Mode Extended (SABME).
    static final int
    UTYPE_TEST
    Unshifted U frame subtype for Test (TEST).
    static final int
    UTYPE_UA
    Unshifted U frame subtype for Unnumbered Acknowledge (UA).
    static final int
    UTYPE_UI
    Unshifted U frame subtype for Unnumbered Information (UI).
    static final int
    UTYPE_XID
    Unshifted U frame subtype for Exchange Identification (XID).

    Fields inherited from interface org.ka2ddo.ax25.AX25FrameSource

    NO_FRAMES

  • Constructor Summary

    Constructors
    Constructor
    Description
    AX25Frame()
    Create an empty AX25Frame initialized for a UI frame containing an APRS packet.

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    compareTo(AX25Frame o)
    Compares this object with the specified object for order.
    static AX25Frame
    decodeFrame(byte[] buf, int offset, int length)
    Create a AX25Frame from a byte array presumed to contain an AX.25 protocol sequence.
    AX25Frame
    dup()
    Create a deep copy of this frame.
    AX25Frame
    dupOnlyHeader()
    Create a deep copy of this frame, excluding the body.
    boolean
    equals(Object obj)
    Indicates whether some other object is "equal to" this one.
    static int
    findSTypeByName(String sTypeName)
    Given a string name, get the numeric S-type value for that type of AX.25 frame.
    static int
    findUTypeByName(String uTypeName)
    Given a string name, get the numeric U-type value for that type of AX.25 frame.
    String
    getAsciiFrame()
    Produce an ASCIIfied version of frame body.
    int
    getChecksum()
    Compute a checksum for this frame to allow efficiently identifying duplicate frames.
    Connector
    getConnector()
    Specify the Connector this message should be transmitted through.
    int
    getEstimatedBitCount()
    Estimate the number of bits needed to transmit this frame over RF in AX.25 standard physical layer (HDLC).
    static String
    getFirstDigi(AX25Callsign[] digipeaters)
    Get the first actual digipeated digipeater station callsign in the digipeater sequence.
    AX25Frame[]
    getFrames(boolean incrementXmtCount, ProtocolFamily protocolId, String senderCallsign)
    Get the frames associated with this FrameSource (in this case, itself).
    int
    getFrameType()
    Get the type of this frame, as stored in the ctl byte.
    String
    getFrameTypeString()
    Generate a string describing the type of the frame.
    static String
    getLastDigi(AX25Callsign[] digipeaters)
    Find the last callsign through which a frame has been digipeated.
    int
    getNR()
    Get the reception sequence number.
    int
    getNS()
    Get the transmission sequence number.
    static String
    getNthDigi(AX25Callsign[] digipeaters, int index)
    Get the Nth digipeated digipeater station callsign in the digipeater sequence.
    int
    getNumTransmitsBeforeDecay()
    Get number of times frame will be retransmitted before inter-packet delay is increased.
    boolean
    getP()
    Get poll bit.
    Set<ProtocolFamily>
    getProtocols()
    Get the protocol family or families that this message corresponds to, so ports that don't support all protocols will not forward inappropriate packets.
    int
    getSType()
    Get the Supervisory frame subtype.
    int
    getUType()
    Get Unordered frame subtype.
    int
    hashCode()
    Returns a hash code value for the object.
    static void
    initializeCmd(AX25Frame f)
    Properly set the isCmd flag of a frame based on the AX25Callsign.h_c bits in the sender and destination addresses.
    boolean
    isDirect()
    Test if this message was sent directly (without any relay station).
    boolean
    isDuplicate(AX25Frame other)
    Test if this frame has the same contents (at least as regards duplicate checking) as the provided older frame.
    static boolean
    isRealCallsign(String callsign)
    Test if a callsign looks like a real callsign (at least one digit somewhere other than the last character, all letters uppercase).
    Boolean
    isRf(int maxDigis)
    Test if this AX25Frame came from an RF connection.
    boolean
    isValid()
    Report whether this packet is strictly valid according to the AX.25 protocol specification,
    void
    setCmd(boolean isCmd)
    Set the command bits in the sender and destination fields.
    String
    toString()
    Return a String representing this AX25Frame object.
    void
    write(OutputStream os)
    Transmit this AX25Frame to an output byte stream.

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • sender

      public AX25Callsign sender
      Callsign of the transmitting station (not of any intermediate digipeaters).

    • dest

      public AX25Callsign dest
      Callsign of the destination station, or some broadcast code with an alternate meaning (such as APRS tocalls and Mic-E encoded latitude and status values).

    • digipeaters

      public AX25Callsign[] digipeaters
      Optional array of digipeater callsigns and aliases, if this frame should be digipeated. May have up to 8 elements in the array.

    • sourcePort

      public transient Connector sourcePort
      Pointer to the I/O port from which this frame was received.

    • ctl

      public byte ctl
      Bitmask identifying the frame type and subtype, and windowing position for connection-oriented I and S frames.
      See Also:

    • ctl2

      public byte ctl2
      Extension of ctl when using 128-segment windowing.
      See Also:

    • pid

      public byte pid
      The one-byte code identifying how to interpret the body of I and UI frames.
      See Also:

    • body

      public byte[] body
      Byte array containing the higher-level protocol payload for I and UI frames.

    • mod128

      public boolean mod128
      Indicates whether 128-segment windowing is used for I frame connections. If this is false, the backwards-compatible 8-segment windowing is used.

    • rcptTime

      public long rcptTime
      The time when this message was received in Java milliseconds since midnight, Jan 1 1970 UTC.

    • parsedAX25Msg

      public AX25Message parsedAX25Msg
      The decoded APRS (or other protocol) message (if the AX25Frame contains a higher-level protocol). May be null.

    • MASK_FRAMETYPE

      public static final int MASK_FRAMETYPE
      The bitmask to extract the frametype bits from the ctl byte of the frame.
      See Also:

    • FRAMETYPE_I

      public static final int FRAMETYPE_I
      Numeric code for information (I) frame type.
      See Also:

    • FRAMETYPE_S

      public static final int FRAMETYPE_S
      Numeric code for supervisory (S) frame type.
      See Also:

    • FRAMETYPE_U

      public static final int FRAMETYPE_U
      Numeric code for unnumbered (U) frame type.
      See Also:

    • MASK_STYPE

      public static final int MASK_STYPE
      Bitmask to extract supervisory (S) frame subtype from the ctl byte.
      See Also:

    • SHIFT_STYPE

      public static final int SHIFT_STYPE
      Bit shift to get least significant bit of S frame subtype into least significant bit of integer.
      See Also:

    • STYPE_RR

      public static final int STYPE_RR
      Unshifted S frame subtype for Receive Ready frame.
      See Also:

    • STYPE_RNR

      public static final int STYPE_RNR
      Unshifted S frame subtype for Receive Not Ready frame.
      See Also:

    • STYPE_REJ

      public static final int STYPE_REJ
      Unshifted S frame subtype for Reject frame.
      See Also:

    • STYPE_SREJ

      public static final int STYPE_SREJ
      Unshifted S frame subtype for Selective Reject frame.
      See Also:

    • MASK_UTYPE

      public static final int MASK_UTYPE
      Bitmask to extract unnumbered (U) frame subtype from the ctl byte.
      See Also:

    • MASK_U_P

      public static final int MASK_U_P
      Bitmask to extract poll/final bit from unnumbered (U) frame ctl byte, mod 8 format.
      See Also:

    • MASK_U_P128

      public static final int MASK_U_P128
      Bitmask to extract poll/final bit from I/S frame 2nd ctl byte, mod 128 format.
      See Also:

    • SHIFT_UTYPE

      public static final int SHIFT_UTYPE
      Bit shift to get least significant bit of U frame subtype into least significant bit of integer.
      See Also:

    • UTYPE_UI

      public static final int UTYPE_UI
      Unshifted U frame subtype for Unnumbered Information (UI).
      See Also:

    • UTYPE_DM

      public static final int UTYPE_DM
      Unshifted U frame subtype for Disconnected Mode (DM).
      See Also:

    • UTYPE_SABM

      public static final int UTYPE_SABM
      Unshifted U frame subtype for Set Asynchronous Balanced Mode (SABM). Only allowed window sizing for AX.25 V2.0 stations.
      See Also:

    • UTYPE_DISC

      public static final int UTYPE_DISC
      Unshifted U frame subtype for Disconnect (DISC).
      See Also:

    • UTYPE_UA

      public static final int UTYPE_UA
      Unshifted U frame subtype for Unnumbered Acknowledge (UA).
      See Also:

    • UTYPE_SABME

      public static final int UTYPE_SABME
      Unshifted U frame subtype for Set Asynchronous Balanced Mode Extended (SABME). Only usable between AX.25 V2.2 stations.
      Since:
      2.2
      See Also:

    • UTYPE_FRMR

      public static final int UTYPE_FRMR
      Deprecated.
      2.0
      Unshifted U frame subtype for obsolete Frame Reject (FRMR).
      See Also:

    • UTYPE_XID

      public static final int UTYPE_XID
      Unshifted U frame subtype for Exchange Identification (XID).
      See Also:

    • UTYPE_TEST

      public static final int UTYPE_TEST
      Unshifted U frame subtype for Test (TEST).
      See Also:

    • PID_X25_PLP

      public static final byte PID_X25_PLP
      Protocol ID for CCITT X.25 PLP (also used by the ROSE network).
      See Also:

    • PID_VJC_TCPIP

      public static final byte PID_VJC_TCPIP
      Protocol ID for Van Jacobson compressed TCP/IP packet, per RFC 1144.
      See Also:

    • PID_VJUC_TCPIP

      public static final byte PID_VJUC_TCPIP
      Protocol ID for Van Jacobson uncompressed TCP/IP packet, per RFC 1144.
      See Also:

    • PID_SEG_FRAG

      public static final byte PID_SEG_FRAG
      Protocol ID for AX.25 segmentation fragment.
      See Also:

    • PID_OPENTRAC

      public static final byte PID_OPENTRAC
      Protocol ID for OpenTRAC.
      See Also:

    • PID_TEXNET

      public static final byte PID_TEXNET
      Protocol ID for TEXNET datagram.
      See Also:

    • PID_LQP

      public static final byte PID_LQP
      Protocol ID for Link Quality Protocol.
      See Also:

    • PID_ATALK

      public static final byte PID_ATALK
      Protocol ID for Appletalk.
      See Also:

    • PID_AARP

      public static final byte PID_AARP
      Protocol ID for Appletalk Address Resolution Protocol (ARP).
      See Also:

    • PID_IP

      public static final byte PID_IP
      Protocol ID for ARPA Internet Protocol.
      See Also:

    • PID_IARP

      public static final byte PID_IARP
      Protocol ID for ARPA Internet Address Resolution Protocol (ARP).
      See Also:

    • PID_FLEXNET

      public static final byte PID_FLEXNET
      Protocol ID for FlexNet.
      See Also:

    • PID_NETROM

      public static final byte PID_NETROM
      Protocol ID for NET/ROM.
      See Also:

    • PID_NOLVL3

      public static final byte PID_NOLVL3
      Protocol ID for no level 3 protocol (also used for APRS).
      See Also:

    • PID_ESCAPE

      public static final byte PID_ESCAPE
      Protocol ID for escape code indicating second byte of PID (not supported).
      See Also:

    • PTYPES_S

      public static final Map<Byte,String> PTYPES_S
      Hashmap of Information (I) or Unnumbered Information (UI) frame protocol ID to protocol name strings.
      See Also:

  • Constructor Details

    • AX25Frame

      public AX25Frame()
      Create an empty AX25Frame initialized for a UI frame containing an APRS packet.

  • Method Details

    • decodeFrame

      public static AX25Frame decodeFrame(byte[] buf, int offset, int length)
      Create a AX25Frame from a byte array presumed to contain an AX.25 protocol sequence.
      Parameters:
      buf - byte array to read frame from
      offset - zero-based index into the array where the frame starts
      length - number of bytes making up the frame
      Returns:
      structured AX25Frame object, or null if byte array doesn't have enough bytes for a frame

    • initializeCmd

      public static void initializeCmd(AX25Frame f)
      Properly set the isCmd flag of a frame based on the AX25Callsign.h_c bits in the sender and destination addresses.
      Parameters:
      f - AX25Frame to set

    • getFrameTypeString

      public String getFrameTypeString()
      Generate a string describing the type of the frame.
      Returns:
      descriptive String

    • getFrameType

      public int getFrameType()
      Get the type of this frame, as stored in the ctl byte.
      Returns:
      frame type code
      See Also:

    • getNS

      public int getNS()
      Get the transmission sequence number.
      Returns:
      sequence number
      Throws:
      IllegalStateException - if this is not an I frame

    • getNR

      public int getNR()
      Get the reception sequence number.
      Returns:
      sequence number
      Throws:
      IllegalStateException - if this is not an I frame

    • getSType

      public int getSType()
      Get the Supervisory frame subtype.
      Returns:
      S frame subtype (masked but not bit-shifted from its position in ctl bitmask)
      See Also:

    • findSTypeByName

      public static int findSTypeByName(String sTypeName)
      Given a string name, get the numeric S-type value for that type of AX.25 frame.
      Parameters:
      sTypeName - String name of frame type
      Returns:
      S-type numeric value, or -1 if no match found

    • getP

      public boolean getP()
      Get poll bit.
      Returns:
      boolean state of poll bit

    • findUTypeByName

      public static int findUTypeByName(String uTypeName)
      Given a string name, get the numeric U-type value for that type of AX.25 frame.
      Parameters:
      uTypeName - String name of frame type
      Returns:
      U-type numeric value, or -1 if no match found

    • getUType

      public int getUType()
      Get Unordered frame subtype.
      Returns:
      U frame subtype (masked but not bit-shifted from its position in ctl bitmask)
      See Also:

    • write

      public void write(OutputStream os) throws IOException
      Transmit this AX25Frame to an output byte stream.
      Parameters:
      os - OutputStream to write the frame to
      Throws:
      IOException - if writing fails

    • dup

      public AX25Frame dup()
      Create a deep copy of this frame.
      Returns:
      duplicate AX25Frame instance

    • dupOnlyHeader

      public AX25Frame dupOnlyHeader()
      Create a deep copy of this frame, excluding the body. This is useful for digipeating messages received from APRS-IS, because it skips making a copy of the message body that will immediately be discarded as part of the 3rd-party re-packaging.
      Returns:
      almost-duplicate AX25Frame instance

    • getFrames

      public AX25Frame[] getFrames(boolean incrementXmtCount, ProtocolFamily protocolId, String senderCallsign)
      Get the frames associated with this FrameSource (in this case, itself).
      Specified by:
      getFrames in interface AX25FrameSource
      Parameters:
      incrementXmtCount - indicate whether the transmit counter (used to cycle through proportional pathing) should be incremented
      protocolId - indicate the protocol to generate this frame for (not relevant for digipeated frames)
      senderCallsign - local sending callsign (ignored if frame already has the callsign filled in)
      Returns:
      one-element array point at this frame

    • getNumTransmitsBeforeDecay

      public int getNumTransmitsBeforeDecay()
      Get number of times frame will be retransmitted before inter-packet delay is increased.
      Specified by:
      getNumTransmitsBeforeDecay in interface AX25FrameSource
      Returns:
      transmission count before interval increase

    • getConnector

      public Connector getConnector()
      Specify the Connector this message should be transmitted through.
      Specified by:
      getConnector in interface AX25FrameSource
      Returns:
      a specific Connector instance to transmit through, or null for all applicable ports (Connector.CAP_XMT_PACKET_DATA and not rejecting this specific packet [such as IGateConnectors shouldn't re-transmit something received from the IGate])
      See Also:

    • isRealCallsign

      public static boolean isRealCallsign(String callsign)
      Test if a callsign looks like a real callsign (at least one digit somewhere other than the last character, all letters uppercase). Note this will automatically strip off the SSID (if any) before testing. Note this is safe for empty strings, and will properly report them as not being a valid real-station callsign,
      Parameters:
      callsign - String callsign to test
      Returns:
      boolean true if callsign looks like real

    • getFirstDigi

      public static String getFirstDigi(AX25Callsign[] digipeaters)
      Get the first actual digipeated digipeater station callsign in the digipeater sequence.
      Parameters:
      digipeaters - array of AX25Callsigns for digipeating a message
      Returns:
      String of first real callsign in sequence, or empty String if no actual digipeater callsign

    • getNthDigi

      public static String getNthDigi(AX25Callsign[] digipeaters, int index)
      Get the Nth digipeated digipeater station callsign in the digipeater sequence.
      Parameters:
      digipeaters - array of AX25Callsigns for digipeating a message
      index - zero-based index of digipeater to report
      Returns:
      String of callsign in sequence, or null if run out of repeated aliases

    • getLastDigi

      public static String getLastDigi(AX25Callsign[] digipeaters)
      Find the last callsign through which a frame has been digipeated.
      Parameters:
      digipeaters - array of digipeater callsigns
      Returns:
      String callsign of last digipeater entry that is marked as used, or empty String if none used

    • isRf

      public Boolean isRf(int maxDigis)
      Test if this AX25Frame came from an RF connection.
      Parameters:
      maxDigis - int maximum number of digipeat hops before we're not going to count it
      Returns:
      Boolean.TRUE if a local Rf transmission, Boolean.FALSE if not RF-only, null if we can't tell

    • isDirect

      public boolean isDirect()
      Test if this message was sent directly (without any relay station).
      Returns:
      boolean true if direct, false if not

    • setCmd

      public void setCmd(boolean isCmd)
      Set the command bits in the sender and destination fields.
      Parameters:
      isCmd - boolean true if this is a command frame, false if a response

    • toString

      public String toString()
      Return a String representing this AX25Frame object.
      Overrides:
      toString in class Object
      Returns:
      descriptive String

    • getAsciiFrame

      public String getAsciiFrame()
      Produce an ASCIIfied version of frame body.
      Returns:
      String version of frame body

    • getChecksum

      public int getChecksum()
      Compute a checksum for this frame to allow efficiently identifying duplicate frames. The checksum only covers the sender callsign and the body, as its purpose is to prevent duplicate digipeating. Alas, it won't work with duplicate transmit IGates, since they change the the sending callsign to that of the IGate and inject a third-party header into the body.
      Returns:
      int checksum of the current contents of this AX25Frame object

    • compareTo

      public int compareTo(AX25Frame o)
      Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.
      Specified by:
      compareTo in interface Comparable<AX25Frame>
      Parameters:
      o - the object to be compared.
      Returns:
      a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.
      Throws:
      ClassCastException - if the specified object's type prevents it from being compared to this object.

    • equals

      public boolean equals(Object obj)
      Indicates whether some other object is "equal to" this one.
      Overrides:
      equals in class Object
      Parameters:
      obj - the reference object with which to compare.
      Returns:
      true if this object is the same as the obj argument; false otherwise.

    • hashCode

      public int hashCode()
      Returns a hash code value for the object.
      Overrides:
      hashCode in class Object
      Returns:
      a hash code value for this object.
      See Also:

    • isDuplicate

      public boolean isDuplicate(AX25Frame other)
      Test if this frame has the same contents (at least as regards duplicate checking) as the provided older frame.
      Parameters:
      other - AX25Frame to compare payloads with
      Returns:
      boolean true if this frame should be treated as a duplicate for digipeating purposes

    • getEstimatedBitCount

      public int getEstimatedBitCount()
      Estimate the number of bits needed to transmit this frame over RF in AX.25 standard physical layer (HDLC).
      Returns:
      bit count estimate

    • isValid

      public boolean isValid()
      Report whether this packet is strictly valid according to the AX.25 protocol specification,
      Returns:
      boolean true if packet is valid

    • getProtocols

      public Set<ProtocolFamily> getProtocols()
      Get the protocol family or families that this message corresponds to, so ports that don't support all protocols will not forward inappropriate packets.
      Returns:
      array of supported ProtocolFamily enums