dnsjit.output.dnscli(3)

NAME
dnsjit.output.dnscli - DNS aware UDP/TCP/TLS client

SYNOPSIS
  local dnscli = require("dnsjit.output.dnscli")

  UDP Receiver Chain
  local output = dnscli.new(dnscli.UDP)
  output:connect("127.0.0.1", "53")
  input:receiver(output)

  TCP Nonblocking
  local output = dnscli.new(dnscli.TCP + dnscli.NONBLOCKING)
  output:send(object)

DESCRIPTION
The DNS client can a core.object.dns or a core.object.payload object via the receiver interface or using send() and send it as DNS query after which it can receive the response by using the producer interface. If the object being sent is a core.object.dns then it will look at includes_dnslen attribute and depending on the protocol it will disregard, include or send the DNS length as an extra packet. If the object being sent is a core.object.payload then no special handling will be done and it will be sent as is. When receiving responses the producer interface will generate core.object.payload objects which may include the DNS length depending on the protocol used and must be handled by the caller.

  MODES
These transport modes and options are available when creating a new Dnscli output.

UDP Create an output using UDP.

TCP Create an output using TCP.

TLS Create an output using TCP and encrypt it with TLS.

NONBLOCKING
    Make the client nonblocking, see send() and produce().

  Functions

Dnscli.new(mode)
    Create a new Dnscli output.

Dnscli:timeout(seconds, nanoseconds)
    Set or return the timeout used for sending and reciving, must be used before connect().

Dnscli:connect(host, port)
    Connect to the host and port and return 0 if successful.

Dnscli:nonblocking()
    Return if nonblocking mode is on (true) or off (false).

Dnscli:send(object, sent)
    Send an object and optionally continue sending after sent bytes. Unlike the receive interface this function lets you know if the sending was successful or not which might be needed on nonblocking connections. Returns -2 on error, -1 if interrupted, timed out or unable to send due to nonblocking, or the number of bytes sent. Note the counters for sent, received, errors and timeouts are not affected by this function.

Dnscli:receive()
    Return the C functions and context for receiving objects, these objects will be sent.

Dnscli:produce()
    Return the C functions and context for producing objects, these objects are received. If nonblocking mode is enabled the producer will return a payload object with length zero if there was nothing to receive. If nonblocking mode is disabled the producer will wait for data and if timed out (see timeout) it will return a payload object with length zero. The producer returns nil on error.

Dnscli:packets()
    Return the number of "packets" sent, actually the number of completely sent payloads.

Dnscli:received()
    Return the number of "packets" received, actually the number of successful calls to recvfrom(2) that returned data.

Dnscli:errors()
    Return the number of errors when sending or receiving.

Dnscli:timeouts()
    Return the number of timeouts when sending or receiving.

SEE ALSO
core.object.dns(3), core.object.payload(3), core.timespec(3)

AUTHORS and CONTRIBUTORS
Jerry Lundström (DNS-OARC), Tomáš Křížek (CZ.NIC), Petr Špaček (ISC)

Maintained by DNS-OARC

    https://www.dns-oarc.net/

BUGS
For issues and feature requests please use:

    https://github.com/DNS-OARC/dnsjit/issues

For question and help please use:

    admin@dns-oarc.net