Ubuntu Manpage: nng_zerotier - ZeroTier transport

NAME

       nng_zerotier - ZeroTier transport

SYNOPSIS

           #include <nng/transport/zerotier/zerotier.h>

           int nng_zt_register(void);

DESCRIPTION

The zt transport provides communication support for NNG applications over a ZeroTier
<http://www.zerotier.com> network, using a Virtual Layer 2 packet facility.

Important

This transport is experimental. To utilize it at present, the library must be built with support, and
linked against a suitable libzerotiercore library. Further information about building with this
support are in the build documentation included with the distribution.

Important

The libzerotiercore library at present is covered under different license terms than the rest of NNG.
Please be careful to review and adhere to the licensing terms.

Important

The ZeroTier transport can take a long time to establish an initial connection — up to even a minute
in extreme cases, while the network topology is configured. Consequently, this transport is not
recommended for use cases involving short-lived programs, but is better for long-running programs
such as background daemons or agents.

While ZeroTier makes use of the host’s IP stack (and UDP in particular), this transport does not use or
require an IP stack on the virtual network; thereby mitigating any considerations about IP address
management.

This service uses Ethernet type 901 to transport packets. Network rules must permit this Ethernet type to
pass in order to have a functional network.

Note

This document assumes that the reader is familiar with ZeroTier concepts and administration.

Registration
Depending upon how the library was built, it may be necessary to register the transport by calling
nng_zt_register(). This function returns zero on success, or an nng error value if the transport cannot
be initialized for any reason.

URI Format
This transport uses URIs using the scheme zt://, followed by a node number (ten hexadecimal digits)
followed by a . delimited, and then a network address (sixteen hexadecimal digits), followed by a colon
(:) and service or port number (decimal value, up to 24-bits). For example, the URI
zt://fedcba9876.0123456789abdef:999 indicates that node fedcba9876 on network 0123456789abcdef is
listening on port 999.

The special value * can be used in lieu of a node number to represent the node’s own node number.

Listeners may use port 0 to indicate that a suitable port number be selected automatically. Applications
using this must determine the selected port number using the nng_listener_getopt() function.

Socket Address
When using an nng_sockaddr structure, the actual structure is of type nng_sockaddr_zt.

Node Presence
By default this transport creates an "ephemeral" node, and used the same ephemeral node for any
additional endpoints created. As this node is ephemeral, the keys associated with it and all associated
data are located in memory and are discarded upon application termination. If a persistent node is
desired, please see the NNG_OPT_ZT_HOME option.

It is possible for a single application to join multiple networks using the same node, or using separate
nodes.

Network Status
A ZeroTier node can be in one of the following states, which can be obtained with the
NNG_OPT_ZT_NETWORK_STATUS option:

NNG_ZT_STATUS_UP
The ZeroTier network is up. This is the only state where it is possible to communicate with peers,
and the only state where the network name (NNG_OPT_ZT_NETWORK_NAME) is available.

NNG_ZT_STATUS_CONFIG
The ZeroTier node is still configuring, network services are not available.

NNG_ZT_STATUS_DENIED
The node does not have permission to join the ZeroTier network.

NNG_ZT_STATUS_NOTFOUND
The ZeroTier network is not found.

NNG_ZT_STATUS_ERROR
Some other ZeroTier error has occurred; the network is not available.

NNG_ZT_STATUS_OBSOLETE
The node is running obsolete software; the network is not available.

NNG_ZT_STATUS_UNKNOWN
The network is in an unknown state. This should not happen, as it indicates that the ZeroTier
software is reporting an unexpected status. The network is most likely not available.

Transport Options
The following transport options are available:

NNG_OPT_ZT_HOME
(string) This option represents the home directory, where the transport can store (and reuse)
persistent state, such as key materials, node identity, and federation membership. This option must
be set before the ZeroTier transport is first used. If this value is empty, then an ephemeral
ZeroTier node is created, and no persistent state is used. The default is to use an ephemeral node.

Note

If this option is set to different values on different sockets, dialers, or listeners, then
separate nodes will be created. It is perfectly valid for an application to have multiple node
identities in this fashion.

NNG_OPT_ZT_NWID
(uint64_t) The 64-bit ZeroTier network number (native byte order).

NNG_OPT_ZT_NODE
(uint64_t) The ZeroTier 40-bit node address (native byte order).

NNG_OPT_ZT_NETWORK_STATUS

(int) The ZeroTier network status. See Network Status for an explanation of this option.

NNG_OPT_ZT_NETWORK_NAME

(string) The name of the network as established by the ZeroTier network administrator.

NNG_OPT_ZT_CONN_TIME
(nng_duration) The time to wait between sending connection attempts, only used with dialers. The
default is 500 msec.

NNG_OPT_ZT_CONN_TRIES
(int) The maximum number of attempts to try to establish a connection before reporting a timeout, and
is only used with dialers. The default is 240, which results in a 2 minute timeout if
NNG_OPT_ZT_CONN_TIME is at its default of 500. If the value is set to 0, then connection attempts
will keep retrying forever.

NNG_OPT_ZT_PING_TIME
(nng_duration) If no traffic has been received from the ZeroTier peer after this period of time, then
a ping message is sent to check if the peer is still alive.

NNG_OPT_ZT_PING_TRIES
(int) If this number of consecutive ping requests are sent to the peer with no response (and no other
intervening traffic), then the peer is assumed to be dead and the connection is closed.

NNG_OPT_ZT_MTU
(size_t) The ZeroTier virtual network MTU (read-only) as configured on the network; this is the
Virtual Layer 2 MTU. The headers used by this transport and the protocols consume some of this for
each message sent over the network. (The transport uses 20-bytes of this, and each protocol may
consume additional space, typically not more than 16-bytes.)

NNG_OPT_ZT_ORBIT
(uint64_t[2]) Write-only array of two uint64_t values, indicating the ID of a ZeroTier <em>moon</em>,
and the node ID of the root server for that moon. (The ID may be zero if the moon ID is the same as
its root server ID, which is conventional.)

NNG_OPT_ZT_DEORBIT
(uint64_t) Write-only option indicating the moon ID to deorbit. If the node is not already orbiting
the moon, then this has no effect.

NAME

SYNOPSIS

DESCRIPTION

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