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# API Reference

Communication over Reticulum networks is achieved by using a simple set of classes exposed by the RNS API. This chapter lists and explains all classes exposed by the Reticulum Network Stack API, along with their method signatures and usage. It can be used as a reference while writing applications that utilise Reticulum, or it can be read in entirity to gain an understanding of the complete functionality of RNS from a developers perspective.

### Reticulum

class RNS.Reticulum(configdir=None, loglevel=None, logdest=None, verbosity=None, require_shared_instance=False)

  This class is used to initialise access to Reticulum within a program. You must create exactly one instance of this class before carrying out any other RNS operations, such as creating destinations or sending traffic. Every independently executed program must create their own instance of the Reticulum class, but Reticulum will automatically handle inter-program communication on the same system, and expose all connected programs to external interfaces as well.

  As soon as an instance of this class is created, Reticulum will start opening and configuring any hardware devices specified in the supplied configuration.

  Currently the first running instance must be kept running while other local instances are connected, as the first created instance will act as a master instance that directly communicates with external hardware such as modems, TNCs and radios. If a master instance is asked to exit, it will not exit until all client processes have terminated (unless killed forcibly).

  If you are running Reticulum on a system with several different programs that use RNS starting and terminating at different times, it will be advantageous to run a master RNS instance as a daemon for other programs to use on demand.

  MTU = 500

    The MTU that Reticulum adheres to, and will expect other peers to adhere to. By default, the MTU is 500 bytes. In custom RNS network implementations, it is possible to change this value, but doing so will completely break compatibility with all other RNS networks. An identical MTU is a prerequisite for peers to communicate in the same network.

    Unless you really know what you are doing, the MTU should be left at the default value.

  ANNOUNCE_CAP = 2

    The maximum percentage of interface bandwidth that, at any given time, may be used to propagate announces. If an announce was scheduled for broadcasting on an interface, but doing so would exceed the allowed bandwidth allocation, the announce will be queued for transmission when there is bandwidth available.

    Reticulum will always prioritise propagating announces with fewer hops, ensuring that distant, large networks with many peers on fast links don’t overwhelm the capacity of smaller networks on slower mediums. If an announce remains queued for an extended amount of time, it will eventually be dropped.

    This value will be applied by default to all created interfaces, but it can be configured individually on a per-interface basis. In general, the global default setting should not be changed, and any alterations should be made on a per-interface basis instead.

  MINIMUM_BITRATE = 5

    Minimum bitrate required across a medium for Reticulum to be able to successfully establish links. Currently 5 bits per second.

  static get_instance()

    Return the currently running Reticulum instance

  static should_use_implicit_proof()

    Returns whether proofs sent are explicit or implicit.

    Returns:

      True if the current running configuration specifies to use implicit proofs. False if not.

  static transport_enabled()

    Returns whether Transport is enabled for the running instance.

    When Transport is enabled, Reticulum will route traffic for other peers, respond to path requests and pass announces over the network.

    Returns:

      True if Transport is enabled, False if not.

  static remote_management_enabled()

    Returns whether remote management is enabled for the running instance.

    When remote management is enabled, authenticated peers can remotely query and manage this instance.

    Returns:

      True if remote management is enabled, False if not.

### Identity

class RNS.Identity(create_keys=True)

  This class is used to manage identities in Reticulum. It provides methods for encryption, decryption, signatures and verification, and is the basis for all encrypted communication over Reticulum networks.

  Parameters:

    create_keys – Specifies whether new encryption and signing keys should be generated.

  CURVE = 'Curve25519'

    The curve used for Elliptic Curve DH key exchanges

  KEYSIZE = 512

    X.25519 key size in bits. A complete key is the concatenation of a 256 bit encryption key, and a 256 bit signing key.

  RATCHETSIZE = 256

    X.25519 ratchet key size in bits.

  RATCHET_EXPIRY = 2592000

    The expiry time for received ratchets in seconds, defaults to 30 days. Reticulum will always use the most recently announced ratchet, and remember it for up to `RATCHET_EXPIRY` since receiving it, after which it will be discarded. If a newer ratchet is announced in the meantime, it will be replace the already known ratchet.

  TRUNCATED_HASHLENGTH = 128

    Constant specifying the truncated hash length (in bits) used by Reticulum for addressable hashes and other purposes. Non-configurable.

  static recall(destination_hash)

    Recall identity for a destination hash.

    Parameters:

      destination_hash – Destination hash as bytes.

    Returns:

      An RNS.Identity instance that can be used to create an outgoing RNS.Destination, or None if the destination is unknown.

  static recall_app_data(destination_hash)

    Recall last heard app_data for a destination hash.

    Parameters:

      destination_hash – Destination hash as bytes.

    Returns:

      Bytes containing app_data, or None if the destination is unknown.

  static full_hash(data)

    Get a SHA-256 hash of passed data.

    Parameters:

      data – Data to be hashed as bytes.

    Returns:

      SHA-256 hash as bytes.

  static truncated_hash(data)

    Get a truncated SHA-256 hash of passed data.

    Parameters:

      data – Data to be hashed as bytes.

    Returns:

      Truncated SHA-256 hash as bytes.

  static get_random_hash()

    Get a random SHA-256 hash.

    Parameters:

      data – Data to be hashed as bytes.

    Returns:

      Truncated SHA-256 hash of random data as bytes.

  static current_ratchet_id(destination_hash)

    Get the ID of the currently used ratchet key for a given destination hash

    Parameters:

      destination_hash – A destination hash as bytes.

    Returns:

      A ratchet ID as bytes or None.

  static from_bytes(prv_bytes)

    Create a new RNS.Identity instance from bytes of private key. Can be used to load previously created and saved identities into Reticulum.

    Parameters:

      prv_bytes – The bytes of private a saved private key. HAZARD! Never use this to generate a new key by feeding random data in prv_bytes.

    Returns:

      A RNS.Identity instance, or None if the bytes data was invalid.

  static from_file(path)

    Create a new RNS.Identity instance from a file. Can be used to load previously created and saved identities into Reticulum.

    Parameters:

      path – The full path to the saved RNS.Identity data

    Returns:

      A RNS.Identity instance, or None if the loaded data was invalid.

  to_file(path)

    Saves the identity to a file. This will write the private key to disk, and anyone with access to this file will be able to decrypt all communication for the identity. Be very careful with this method.

    Parameters:

      path – The full path specifying where to save the identity.

    Returns:

      True if the file was saved, otherwise False.

  get_private_key()
    Returns:

      The private key as bytes

  get_public_key()
    Returns:

      The public key as bytes

  load_private_key(prv_bytes)

    Load a private key into the instance.

    Parameters:

      prv_bytes – The private key as bytes.

    Returns:

      True if the key was loaded, otherwise False.

  load_public_key(pub_bytes)

    Load a public key into the instance.

    Parameters:

      pub_bytes – The public key as bytes.

    Returns:

      True if the key was loaded, otherwise False.

  encrypt(plaintext, ratchet=None)

    Encrypts information for the identity.

    Parameters:

      plaintext – The plaintext to be encrypted as bytes.

    Returns:

      Ciphertext token as bytes.

    Raises:

      KeyError if the instance does not hold a public key.

  decrypt(ciphertext_token, ratchets=None, enforce_ratchets=False, ratchet_id_receiver=None)

    Decrypts information for the identity.

    Parameters:

      ciphertext – The ciphertext to be decrypted as bytes.

    Returns:

      Plaintext as bytes, or None if decryption fails.

    Raises:

      KeyError if the instance does not hold a private key.

  sign(message)

    Signs information by the identity.

    Parameters:

      message – The message to be signed as bytes.

    Returns:

      Signature as bytes.

    Raises:

      KeyError if the instance does not hold a private key.

  validate(signature, message)

    Validates the signature of a signed message.

    Parameters:

      - signature – The signature to be validated as bytes.

      - message – The message to be validated as bytes.

    Returns:

      True if the signature is valid, otherwise False.

    Raises:

      KeyError if the instance does not hold a public key.

### Destination

class RNS.Destination(identity, direction, type, app_name, *aspects)

  A class used to describe endpoints in a Reticulum Network. Destination instances are used both to create outgoing and incoming endpoints. The destination type will decide if encryption, and what type, is used in communication with the endpoint. A destination can also announce its presence on the network, which will distribute necessary keys for encrypted communication with it.

  Parameters:

    - identity – An instance of RNS.Identity. Can hold only public keys for an outgoing destination, or holding private keys for an ingoing.

    - direction – `RNS.Destination.IN` or `RNS.Destination.OUT`.

    - type – `RNS.Destination.SINGLE`, `RNS.Destination.GROUP` or `RNS.Destination.PLAIN`.

    - app_name – A string specifying the app name.

    - *aspects – Any non-zero number of string arguments.

  RATCHET_COUNT = 512

    The default number of generated ratchet keys a destination will retain, if it has ratchets enabled.

  RATCHET_INTERVAL = 1800

    The minimum interval between rotating ratchet keys, in seconds.

  static expand_name(identity, app_name, *aspects)
    Returns:

      A string containing the full human-readable name of the destination, for an app_name and a number of aspects.

  static app_and_aspects_from_name(full_name)
    Returns:

      A tuple containing the app name and a list of aspects, for a full-name string.

  static hash_from_name_and_identity(full_name, identity)
    Returns:

      A destination name in adressable hash form, for a full name string and Identity instance.

  static hash(identity, app_name, *aspects)
    Returns:

      A destination name in adressable hash form, for an app_name and a number of aspects.

  announce(app_data=None, path_response=False, attached_interface=None, tag=None, send=True)

    Creates an announce packet for this destination and broadcasts it on all relevant interfaces. Application specific data can be added to the announce.

    Parameters:

      - app_data – bytes containing the app_data.

      - path_response – Internal flag used by RNS.Transport. Ignore.

  accepts_links(accepts=None)

    Set or query whether the destination accepts incoming link requests.

    Parameters:

      accepts – If `True` or `False`, this method sets whether the destination accepts incoming link requests. If not provided or `None`, the method returns whether the destination currently accepts link requests.

    Returns:

      `True` or `False` depending on whether the destination accepts incoming link requests, if the accepts parameter is not provided or `None`.

  set_link_established_callback(callback)

    Registers a function to be called when a link has been established to this destination.

    Parameters:

      callback – A function or method with the signature callback(link) to be called when a new link is established with this destination.

  set_packet_callback(callback)

    Registers a function to be called when a packet has been received by this destination.

    Parameters:

      callback – A function or method with the signature callback(data, packet) to be called when this destination receives a packet.

  set_proof_requested_callback(callback)

    Registers a function to be called when a proof has been requested for a packet sent to this destination. Allows control over when and if proofs should be returned for received packets.

    Parameters:

      callback – A function or method to with the signature callback(packet) be called when a packet that requests a proof is received. The callback must return one of True or False. If the callback returns True, a proof will be sent. If it returns False, a proof will not be sent.

  set_proof_strategy(proof_strategy)

    Sets the destinations proof strategy.

    Parameters:

      proof_strategy – One of `RNS.Destination.PROVE_NONE`, `RNS.Destination.PROVE_ALL` or `RNS.Destination.PROVE_APP`. If `RNS.Destination.PROVE_APP` is set, the proof_requested_callback will be called to determine whether a proof should be sent or not.

  register_request_handler(path, response_generator=None, allow=ALLOW_NONE, allowed_list=None)

    Registers a request handler.

    Parameters:

      - path – The path for the request handler to be registered.

      - response_generator – A function or method with the signature response_generator(path, data, request_id, link_id, remote_identity, requested_at) to be called. Whatever this funcion returns will be sent as a response to the requester. If the function returns `None`, no response will be sent.

      - allow – One of `RNS.Destination.ALLOW_NONE`, `RNS.Destination.ALLOW_ALL` or `RNS.Destination.ALLOW_LIST`. If `RNS.Destination.ALLOW_LIST` is set, the request handler will only respond to requests for identified peers in the supplied list.

      - allowed_list – A list of bytes-like RNS.Identity hashes.

    Raises:

      `ValueError` if any of the supplied arguments are invalid.

  deregister_request_handler(path)

    Deregisters a request handler.

    Parameters:

      path – The path for the request handler to be deregistered.

    Returns:

      True if the handler was deregistered, otherwise False.

  enable_ratchets(ratchets_path)

    Enables ratchets on the destination. When ratchets are enabled, Reticulum will automatically rotate the keys used to encrypt packets to this destination, and include the latest ratchet key in announces.

    Enabling ratchets on a destination will provide forward secrecy for packets sent to that destination, even when sent outside a `Link`. The normal Reticulum `Link` establishment procedure already performs its own ephemeral key exchange for each link establishment, which means that ratchets are not necessary to provide forward secrecy for links.

    Enabling ratchets will have a small impact on announce size, adding 32 bytes to every sent announce.

    Parameters:

      ratchets_path – The path to a file to store ratchet data in.

    Returns:

      True if the operation succeeded, otherwise False.

  enforce_ratchets()

    When ratchet enforcement is enabled, this destination will never accept packets that use its base Identity key for encryption, but only accept packets encrypted with one of the retained ratchet keys.

  set_retained_ratchets(retained_ratchets)

    Sets the number of previously generated ratchet keys this destination will retain, and try to use when decrypting incoming packets. Defaults to `Destination.RATCHET_COUNT`.

    Parameters:

      retained_ratchets – The number of generated ratchets to retain.

    Returns:

      True if the operation succeeded, False if not.

  set_ratchet_interval(interval)

    Sets the minimum interval in seconds between ratchet key rotation. Defaults to `Destination.RATCHET_INTERVAL`.

    Parameters:

      interval – The minimum interval in seconds.

    Returns:

      True if the operation succeeded, False if not.

  create_keys()

    For a `RNS.Destination.GROUP` type destination, creates a new symmetric key.

    Raises:

      `TypeError` if called on an incompatible type of destination.

  get_private_key()

    For a `RNS.Destination.GROUP` type destination, returns the symmetric private key.

    Raises:

      `TypeError` if called on an incompatible type of destination.

  load_private_key(key)

    For a `RNS.Destination.GROUP` type destination, loads a symmetric private key.

    Parameters:

      key – A bytes-like containing the symmetric key.

    Raises:

      `TypeError` if called on an incompatible type of destination.

  encrypt(plaintext)

    Encrypts information for `RNS.Destination.SINGLE` or `RNS.Destination.GROUP` type destination.

    Parameters:

      plaintext – A bytes-like containing the plaintext to be encrypted.

    Raises:

      `ValueError` if destination does not hold a necessary key for encryption.

  decrypt(ciphertext)

    Decrypts information for `RNS.Destination.SINGLE` or `RNS.Destination.GROUP` type destination.

    Parameters:

      ciphertext – Bytes containing the ciphertext to be decrypted.

    Raises:

      `ValueError` if destination does not hold a necessary key for decryption.

  sign(message)

    Signs information for `RNS.Destination.SINGLE` type destination.

    Parameters:

      message – Bytes containing the message to be signed.

    Returns:

      A bytes-like containing the message signature, or None if the destination could not sign the message.

  set_default_app_data(app_data=None)

    Sets the default app_data for the destination. If set, the default app_data will be included in every announce sent by the destination, unless other app_data is specified in the announce method.

    Parameters:

      app_data – A bytes-like containing the default app_data, or a callable returning a bytes-like containing the app_data.

  clear_default_app_data()

    Clears default app_data previously set for the destination.

### Packet

class RNS.Packet(destination, data, create_receipt=True)

  The Packet class is used to create packet instances that can be sent over a Reticulum network. Packets will automatically be encrypted if they are addressed to a `RNS.Destination.SINGLE` destination, `RNS.Destination.GROUP` destination or a RNS.Link.

  For `RNS.Destination.GROUP` destinations, Reticulum will use the pre-shared key configured for the destination. All packets to group destinations are encrypted with the same AES-128 key.

  For `RNS.Destination.SINGLE` destinations, Reticulum will use a newly derived ephemeral AES-128 key for every packet.

  For RNS.Link destinations, Reticulum will use per-link ephemeral keys, and offers Forward Secrecy.

  Parameters:

    - destination – A RNS.Destination instance to which the packet will be sent.

    - data – The data payload to be included in the packet as bytes.

    - create_receipt – Specifies whether a RNS.PacketReceipt should be created when instantiating the packet.

  ENCRYPTED_MDU = 383

    The maximum size of the payload data in a single encrypted packet

  PLAIN_MDU = 464

    The maximum size of the payload data in a single unencrypted packet

  send()

    Sends the packet.

    Returns:

      A RNS.PacketReceipt instance if create_receipt was set to True when the packet was instantiated, if not returns None. If the packet could not be sent False is returned.

  resend()

    Re-sends the packet.

    Returns:

      A RNS.PacketReceipt instance if create_receipt was set to True when the packet was instantiated, if not returns None. If the packet could not be sent False is returned.

  get_rssi()
    Returns:

      The physical layer Received Signal Strength Indication if available, otherwise `None`.

  get_snr()
    Returns:

      The physical layer Signal-to-Noise Ratio if available, otherwise `None`.

  get_q()
    Returns:

      The physical layer Link Quality if available, otherwise `None`.

### Packet Receipt

class RNS.PacketReceipt

  The PacketReceipt class is used to receive notifications about RNS.Packet instances sent over the network. Instances of this class are never created manually, but always returned from the send() method of a RNS.Packet instance.

  get_status()
    Returns:

      The status of the associated RNS.Packet instance. Can be one of `RNS.PacketReceipt.SENT`, `RNS.PacketReceipt.DELIVERED`, `RNS.PacketReceipt.FAILED` or `RNS.PacketReceipt.CULLED`.

  get_rtt()
    Returns:

      The round-trip-time in seconds

  set_timeout(timeout)

    Sets a timeout in seconds

    Parameters:

      timeout – The timeout in seconds.

  set_delivery_callback(callback)

    Sets a function that gets called if a successfull delivery has been proven.

    Parameters:

      callback – A callable with the signature callback(packet_receipt)

  set_timeout_callback(callback)

    Sets a function that gets called if the delivery times out.

    Parameters:

      callback – A callable with the signature callback(packet_receipt)

### Link

class RNS.Link(destination, established_callback=None, closed_callback=None)

  This class is used to establish and manage links to other peers. When a link instance is created, Reticulum will attempt to establish verified and encrypted connectivity with the specified destination.

  Parameters:

    - destination – A RNS.Destination instance which to establish a link to.

    - established_callback – An optional function or method with the signature callback(link) to be called when the link has been established.

    - closed_callback – An optional function or method with the signature callback(link) to be called when the link is closed.

  CURVE = 'Curve25519'

    The curve used for Elliptic Curve DH key exchanges

  ESTABLISHMENT_TIMEOUT_PER_HOP = 6

    Timeout for link establishment in seconds per hop to destination.

  KEEPALIVE_TIMEOUT_FACTOR = 4

    RTT timeout factor used in link timeout calculation.

  STALE_GRACE = 2

    Grace period in seconds used in link timeout calculation.

  KEEPALIVE = 360

    Interval for sending keep-alive packets on established links in seconds.

  STALE_TIME = 720

    If no traffic or keep-alive packets are received within this period, the link will be marked as stale, and a final keep-alive packet will be sent. If after this no traffic or keep-alive packets are received within `RTT` * `KEEPALIVE_TIMEOUT_FACTOR` + `STALE_GRACE`, the link is considered timed out, and will be torn down.

  identify(identity)

    Identifies the initiator of the link to the remote peer. This can only happen once the link has been established, and is carried out over the encrypted link. The identity is only revealed to the remote peer, and initiator anonymity is thus preserved. This method can be used for authentication.

    Parameters:

      identity – An RNS.Identity instance to identify as.

  request(path, data=None, response_callback=None, failed_callback=None, progress_callback=None, timeout=None)

    Sends a request to the remote peer.

    Parameters:

      - path – The request path.

      - response_callback – An optional function or method with the signature response_callback(request_receipt) to be called when a response is received. See the Request Example for more info.

      - failed_callback – An optional function or method with the signature failed_callback(request_receipt) to be called when a request fails. See the Request Example for more info.

      - progress_callback – An optional function or method with the signature progress_callback(request_receipt) to be called when progress is made receiving the response. Progress can be accessed as a float between 0.0 and 1.0 by the request_receipt.progress property.

      - timeout – An optional timeout in seconds for the request. If None is supplied it will be calculated based on link RTT.

    Returns:

      A RNS.RequestReceipt instance if the request was sent, or False if it was not.

  track_phy_stats(track)

    You can enable physical layer statistics on a per-link basis. If this is enabled, and the link is running over an interface that supports reporting physical layer statistics, you will be able to retrieve stats such as RSSI, SNR and physical Link Quality for the link.

    Parameters:

      track – Whether or not to keep track of physical layer statistics. Value must be `True` or `False`.

  get_rssi()
    Returns:

      The physical layer Received Signal Strength Indication if available, otherwise `None`. Physical layer statistics must be enabled on the link for this method to return a value.

  get_snr()
    Returns:

      The physical layer Signal-to-Noise Ratio if available, otherwise `None`. Physical layer statistics must be enabled on the link for this method to return a value.

  get_q()
    Returns:

      The physical layer Link Quality if available, otherwise `None`. Physical layer statistics must be enabled on the link for this method to return a value.

  get_establishment_rate()
    Returns:

      The data transfer rate at which the link establishment procedure ocurred, in bits per second.

  get_age()
    Returns:

      The time in seconds since this link was established.

  no_inbound_for()
    Returns:

      The time in seconds since last inbound packet on the link. This includes keepalive packets.

  no_outbound_for()
    Returns:

      The time in seconds since last outbound packet on the link. This includes keepalive packets.

  no_data_for()
    Returns:

      The time in seconds since payload data traversed the link. This excludes keepalive packets.

  inactive_for()
    Returns:

      The time in seconds since activity on the link. This includes keepalive packets.

  get_remote_identity()
    Returns:

      The identity of the remote peer, if it is known. Calling this method will not query the remote initiator to reveal its identity. Returns `None` if the link initiator has not already independently called the `identify(identity)` method.

  teardown()

    Closes the link and purges encryption keys. New keys will be used if a new link to the same destination is established.

  get_channel()

    Get the `Channel` for this link.

    Returns:

      `Channel` object

  set_link_closed_callback(callback)

    Registers a function to be called when a link has been torn down.

    Parameters:

      callback – A function or method with the signature callback(link) to be called.

  set_packet_callback(callback)

    Registers a function to be called when a packet has been received over this link.

    Parameters:

      callback – A function or method with the signature callback(message, packet) to be called.

  set_resource_callback(callback)

    Registers a function to be called when a resource has been advertised over this link. If the function returns True the resource will be accepted. If it returns False it will be ignored.

    Parameters:

      callback – A function or method with the signature callback(resource) to be called. Please note that only the basic information of the resource is available at this time, such as get_transfer_size(), get_data_size(), get_parts() and is_compressed().

  set_resource_started_callback(callback)

    Registers a function to be called when a resource has begun transferring over this link.

    Parameters:

      callback – A function or method with the signature callback(resource) to be called.

  set_resource_concluded_callback(callback)

    Registers a function to be called when a resource has concluded transferring over this link.

    Parameters:

      callback – A function or method with the signature callback(resource) to be called.

  set_remote_identified_callback(callback)

    Registers a function to be called when an initiating peer has identified over this link.

    Parameters:

      callback – A function or method with the signature callback(link, identity) to be called.

  set_resource_strategy(resource_strategy)

    Sets the resource strategy for the link.

    Parameters:

      resource_strategy – One of `RNS.Link.ACCEPT_NONE`, `RNS.Link.ACCEPT_ALL` or `RNS.Link.ACCEPT_APP`. If `RNS.Link.ACCEPT_APP` is set, the resource_callback will be called to determine whether the resource should be accepted or not.

    Raises:

      TypeError if the resource strategy is unsupported.

### Request Receipt

class RNS.RequestReceipt

  An instance of this class is returned by the `request` method of `RNS.Link` instances. It should never be instantiated manually. It provides methods to check status, response time and response data when the request concludes.

  get_request_id()
    Returns:

      The request ID as bytes.

  get_status()
    Returns:

      The current status of the request, one of `RNS.RequestReceipt.FAILED`, `RNS.RequestReceipt.SENT`, `RNS.RequestReceipt.DELIVERED`, `RNS.RequestReceipt.READY`.

  get_progress()
    Returns:

      The progress of a response being received as a float between 0.0 and 1.0.

  get_response()
    Returns:

      The response as bytes if it is ready, otherwise None.

  get_response_time()
    Returns:

      The response time of the request in seconds.

  concluded()
    Returns:

      True if the associated request has concluded (successfully or with a failure), otherwise False.

### Resource

class RNS.Resource(data, link, advertise=True, auto_compress=True, callback=None, progress_callback=None, timeout=None)

  The Resource class allows transferring arbitrary amounts of data over a link. It will automatically handle sequencing, compression, coordination and checksumming.

  Parameters:

    - data – The data to be transferred. Can be bytes or an open file handle. See the Filetransfer Example for details.

    - link – The RNS.Link instance on which to transfer the data.

    - advertise – Optional. Whether to automatically advertise the resource. Can be True or False.

    - auto_compress – Optional. Whether to auto-compress the resource. Can be True or False.

    - callback – An optional callable with the signature callback(resource). Will be called when the resource transfer concludes.

    - progress_callback – An optional callable with the signature callback(resource). Will be called whenever the resource transfer progress is updated.

  advertise()

    Advertise the resource. If the other end of the link accepts the resource advertisement it will begin transferring.

  cancel()

    Cancels transferring the resource.

  get_progress()
    Returns:

      The current progress of the resource transfer as a float between 0.0 and 1.0.

  get_transfer_size()
    Returns:

      The number of bytes needed to transfer the resource.

  get_data_size()
    Returns:

      The total data size of the resource.

  get_parts()
    Returns:

      The number of parts the resource will be transferred in.

  get_segments()
    Returns:

      The number of segments the resource is divided into.

  get_hash()
    Returns:

      The hash of the resource.

  is_compressed()
    Returns:

      Whether the resource is compressed.

### Channel

class RNS.Channel.Channel

  Provides reliable delivery of messages over a link.

  `Channel` differs from `Request` and `Resource` in some important ways:

  > Continuous

  >   Messages can be sent or received as long as the `Link` is open.

  > Bi-directional

  >   Messages can be sent in either direction on the `Link`; neither end is the client or server.

  > Size-constrained

  >   Messages must be encoded into a single packet.

  `Channel` is similar to `Packet`, except that it provides reliable delivery (automatic retries) as well as a structure for exchanging several types of messages over the `Link`.

  `Channel` is not instantiated directly, but rather obtained from a `Link` with `get_channel()`.

  register_message_type(message_class: Type[MessageBase])

    Register a message class for reception over a `Channel`.

    Message classes must extend `MessageBase`.

    Parameters:

      message_class – Class to register

  add_message_handler(callback: MessageCallbackType)

    Add a handler for incoming messages. A handler has the following signature:

    `(message: MessageBase) -> bool`

    Handlers are processed in the order they are added. If any handler returns True, processing of the message stops; handlers after the returning handler will not be called.

    Parameters:

      callback – Function to call

  remove_message_handler(callback: MessageCallbackType)

    Remove a handler added with `add_message_handler`.

    Parameters:

      callback – handler to remove

  is_ready_to_send() → bool

    Check if `Channel` is ready to send.

    Returns:

      True if ready

  send(message: MessageBase) → Envelope

    Send a message. If a message send is attempted and `Channel` is not ready, an exception is thrown.

    Parameters:

      message – an instance of a `MessageBase` subclass

  property MDU

    Maximum Data Unit: the number of bytes available for a message to consume in a single send. This value is adjusted from the `Link` MDU to accommodate message header information.

    Returns:

      number of bytes available

### MessageBase

class RNS.MessageBase

  Base type for any messages sent or received on a Channel. Subclasses must define the two abstract methods as well as the `MSGTYPE` class variable.

  MSGTYPE = None

    Defines a unique identifier for a message class.

    - Must be unique within all classes registered with a `Channel`

    - Must be less than `0xf000`. Values greater than or equal to `0xf000` are reserved.

  abstract pack() → bytes

    Create and return the binary representation of the message

    Returns:

      binary representation of message

  abstract unpack(raw: bytes)

    Populate message from binary representation

    Parameters:

      raw – binary representation

### Buffer

class RNS.Buffer

  Static functions for creating buffered streams that send and receive over a `Channel`.

  These functions use `BufferedReader`, `BufferedWriter`, and `BufferedRWPair` to add buffering to `RawChannelReader` and `RawChannelWriter`.

  static create_reader(stream_id: int, channel: Channel, ready_callback: Optional[Callable[[int], None]] = None) → BufferedReader

    Create a buffered reader that reads binary data sent over a `Channel`, with an optional callback when new data is available.

    Callback signature: `(ready_bytes: int) -> None`

    For more information on the reader-specific functions of this object, see the Python documentation for `BufferedReader`

    Parameters:

      - stream_id – the local stream id to receive from

      - channel – the channel to receive on

      - ready_callback – function to call when new data is available

    Returns:

      a BufferedReader object

  static create_writer(stream_id: int, channel: Channel) → BufferedWriter

    Create a buffered writer that writes binary data over a `Channel`.

    For more information on the writer-specific functions of this object, see the Python documentation for `BufferedWriter`

    Parameters:

      - stream_id – the remote stream id to send to

      - channel – the channel to send on

    Returns:

      a BufferedWriter object

  static create_bidirectional_buffer(receive_stream_id: int, send_stream_id: int, channel: Channel, ready_callback: Optional[Callable[[int], None]] = None) → BufferedRWPair

    Create a buffered reader/writer pair that reads and writes binary data over a `Channel`, with an optional callback when new data is available.

    Callback signature: `(ready_bytes: int) -> None`

    For more information on the reader-specific functions of this object, see the Python documentation for `BufferedRWPair`

    Parameters:

      - receive_stream_id – the local stream id to receive at

      - send_stream_id – the remote stream id to send to

      - channel – the channel to send and receive on

      - ready_callback – function to call when new data is available

    Returns:

      a BufferedRWPair object

### RawChannelReader

class RNS.RawChannelReader(stream_id: int, channel: Channel)

  An implementation of RawIOBase that receives binary stream data sent over a `Channel`.

  > This class generally need not be instantiated directly. Use `RNS.Buffer.create_reader()`, `RNS.Buffer.create_writer()`, and `RNS.Buffer.create_bidirectional_buffer()` functions to create buffered streams with optional callbacks.

  > For additional information on the API of this object, see the Python documentation for `RawIOBase`.

  __init__(stream_id: int, channel: Channel)

    Create a raw channel reader.

    Parameters:

      - stream_id – local stream id to receive at

      - channel – `Channel` object to receive from

  add_ready_callback(cb: Callable[[int], None])

    Add a function to be called when new data is available. The function should have the signature `(ready_bytes: int) -> None`

    Parameters:

      cb – function to call

  remove_ready_callback(cb: Callable[[int], None])

    Remove a function added with `RNS.RawChannelReader.add_ready_callback()`

    Parameters:

      cb – function to remove

### RawChannelWriter

class RNS.RawChannelWriter(stream_id: int, channel: Channel)

  An implementation of RawIOBase that receives binary stream data sent over a channel.

  > This class generally need not be instantiated directly. Use `RNS.Buffer.create_reader()`, `RNS.Buffer.create_writer()`, and `RNS.Buffer.create_bidirectional_buffer()` functions to create buffered streams with optional callbacks.

  > For additional information on the API of this object, see the Python documentation for `RawIOBase`.

  __init__(stream_id: int, channel: Channel)

    Create a raw channel writer.

    Parameters:

      - stream_id – remote stream id to sent do

      - channel – `Channel` object to send on

### Transport

class RNS.Transport

  Through static methods of this class you can interact with the Transport system of Reticulum.

  PATHFINDER_M = 128

    Maximum amount of hops that Reticulum will transport a packet.

  static register_announce_handler(handler)

    Registers an announce handler.

    Parameters:

      handler – Must be an object with an aspect_filter attribute and a received_announce(destination_hash, announced_identity, app_data) or received_announce(destination_hash, announced_identity, app_data, announce_packet_hash) callable. Can optionally have a receive_path_responses attribute set to `True`, to also receive all path responses, in addition to live announces. See the Announce Example for more info.

  static deregister_announce_handler(handler)

    Deregisters an announce handler.

    Parameters:

      handler – The announce handler to be deregistered.

  static has_path(destination_hash)
    Parameters:

      destination_hash – A destination hash as bytes.

    Returns:

      True if a path to the destination is known, otherwise False.

  static hops_to(destination_hash)
    Parameters:

      destination_hash – A destination hash as bytes.

    Returns:

      The number of hops to the specified destination, or `RNS.Transport.PATHFINDER_M` if the number of hops is unknown.

  static next_hop(destination_hash)
    Parameters:

      destination_hash – A destination hash as bytes.

    Returns:

      The destination hash as bytes for the next hop to the specified destination, or None if the next hop is unknown.

  static next_hop_interface(destination_hash)
    Parameters:

      destination_hash – A destination hash as bytes.

    Returns:

      The interface for the next hop to the specified destination, or None if the interface is unknown.

  static request_path(destination_hash, on_interface=None, tag=None, recursive=False)

    Requests a path to the destination from the network. If another reachable peer on the network knows a path, it will announce it.

    Parameters:

      - destination_hash – A destination hash as bytes.

      - on_interface – If specified, the path request will only be sent on this interface. In normal use, Reticulum handles this automatically, and this parameter should not be used.