OpenDHT

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OpenDHT is a lightweight C++14 Distributed Hash Table implementation. It provides an easy to use distributed in-memory data store. Every node in the network can read and write values to the store. Values are distributed over the network, with redundancy.

Build

Tool

  • Operating system 
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    Linux ubuntu 5.8.0-43-generic #49~20.04.1-Ubuntu SMP Fri Feb 5 09:57:56 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
  • GCC 
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    gcc (Ubuntu 10.2.0-5ubuntu1~20.04) 10.2.0
    Copyright (C) 2020 Free Software Foundation, Inc.
    This is free software; see the source for copying conditions.  There is NO
    warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  • Clang 
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    clang version 11.0.0
    Target: x86_64-unknown-linux-gnu
    Thread model: posix
    InstalledDir: /usr/local/bin
  • CMake 
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    cmake version 3.19.4

    CMake suite maintained and supported by Kitware (kitware.com/cmake).

Dependency

  • OpenDHT dependencies 
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    sudo apt install libncurses5-dev libreadline-dev nettle-dev libgnutls28-dev libargon2-0-dev libmsgpack-dev  libssl-dev libfmt-dev libjsoncpp-dev libhttp-parser-dev libasio-dev
  • Python binding dependencies 
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    sudo apt-get install cython3 python3-dev python3-setuptools
  • Restinio 
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    mkdir restinio && cd restinio
    wget https://github.com/aberaud/restinio/archive/2c0b6f5e5ba04d7a74e8406a3df1fd433680599d.tar.g
    ls -l && tar -xzf 2c0b6f5e5ba04d7a74e8406a3df1fd433680599d.tar.gz
    cd restinio-2c0b6f5e5ba04d7a74e8406a3df1fd433680599d/dev
    cmake -DCMAKE_INSTALL_PREFIX=/usr -DRESTINIO_TEST=OFF -DRESTINIO_SAMPLE=OFF -DRESTINIO_INSTALL_SAMPLES=OFF -DRESTINIO_BENCH=OFF -DRESTINIO_INSTALL_BENCHES=OFF -DRESTINIO_FIND_DEPS=ON -DRESTINIO_ALLOW_SOBJECTIZER=Off -DRESTINIO_USE_BOOST_ASIO=none .
    make -j2
    sudo make install
    cd ../../../ && rm -rf restinio

Build

  • Clone the repo 
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    git clone https://github.com/savoirfairelinux/opendht.git
  • Build and install 
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    cd opendht
    mkdir build && cd build
    cmake -DOPENDHT_PYTHON=ON -DCMAKE_INSTALL_PREFIX=/usr ..
    make -j2
    sudo make install

Example

Python3

  • Example code 
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    import opendht as dht

    node = dht.DhtRunner()
    node.run()

    # Join the network through any running node,
    # here using a known bootstrap node.
    node.bootstrap("bootstrap.jami.net", "4222")

    # blocking call (provide callback arguments to make the call non-blocking)
    node.put(dht.InfoHash.get("unique_key"), dht.Value(b'some binary data'))

    results = node.get(dht.InfoHash.get("unique_key"))
    for r in results:
        print(r)
  • Command line result 
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    Value[id:640b4d1af8908cc4 data:736f6d652062696e6172792064617461]
  • Decode 
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    >>> bytearray.fromhex("736f6d652062696e6172792064617461").decode()
    'some binary data'

Dhtnode

Dhtnode is a command line tool which allows to run a DHT node and perform operations to the distributed in-memory data store.

Command Line Running

Dhtnode can run directly in command line. There are several parameters that can be set when creating a dht node.

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dhtnode [-p local_port] [-b bootstrap_host:port] [-n netid] [-i] [-D] [-f] [-v [-l logfile|-L]] [-s|-d]
  • -b allows to specify a bootstrap node address (can be any running node of the DHT network)
  • -p allows to specify the local UDP port to bind (optional). If not set, will use any available port. Note that the default OpenDHT port (to ideally use for public nodes) is 4222
  • -D enables the multicast automatic local peer discovery mechanism

Command Line Interface

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OpenDHT command line interface (CLI)
Possible commands:
h, help    Print this help message.
x, quit    Quit the program.
log        Start/stop printing DHT logs.

Node information:
ll         Print basic information and stats about the current node.
ls [key]   Print basic information about current search(es).
ld [key]   Print basic information about currently stored values on this node (or key).
lr         Print the full current routing table of this node.

Operations on the DHT:
b <ip:port>           Ping potential node at given IP address/port.
g <key>               Get values at <key>.
l <key>               Listen for value changes at <key>.
cl <key> <token>      Cancel listen for <token> and <key>.
p <key> <str>         Put string value at <key>.
pp <key> <str>        Put string value at <key> (persistent version).
cpp <key> <id>        Cancel persistent put operation for <key> and value <id>.
s <key> <str>         Put string value at <key>, signed with our generated private key.
e <key> <dest> <str>  Put string value at <key>, encrypted for <dest> with its public key (if found).
cc                    Trigger connectivity changed signal.

Indexation operations on the DHT:
il <name> <key> [exact match]   Lookup the index named <name> with the key <key>.
                                Set [exact match] to 'false' for inexact match lookup.
ii <name> <key> <value>         Inserts the value <value> under the key <key> in the index named <name>.

Demo

  • Create node 
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    zhiqich@ubuntu:~/Documents/opendht$ dhtnode -D
    OpenDHT node db159e7c839b5872692b244deeb849eb8195233b running on port 39901
     (type 'h' or 'help' for a list of possible commands)
  • Check stats 
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    >> ll
    >> OpenDHT node db159e7c839b5872692b244deeb849eb8195233b running on port 39901
    1 ongoing operations
    IPv4 stats:
    Known nodes: 0 good, 0 dubious, 0 incoming.
    0 searches, 0 total cached nodes

    IPv6 stats:
    Known nodes: 0 good, 0 dubious, 0 incoming.
    0 searches, 0 total cached nodes
  • Put value 
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    >> p test "this is a test string"
    Using h(test) = a94a8fe5ccb19ba61c4c0873d391e987982fbbd3
    >> Put: success, took 1.36 ms. Value ID: 8530bb7894ee21b1
  • Get value 
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    >> g test
    Using h(test) = a94a8fe5ccb19ba61c4c0873d391e987982fbbd3
    >> Get: found 1 value(s) after 178 us
     Value[id:8530bb7894ee21b1 data(text/plain):""this"]
    Get: completed, took 1.4 ms

Dhtchat

Dhtchat is a simple IM client working over the dht.

Usage

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zhiqich@ubuntu:~/Documents/opendht$ dhtchat -h
Usage: dhtchat [-n network_id] [-p local_port] [-b bootstrap_host[:port]]

dhtchat, a simple OpenDHT command line chat client.
Report bugs to: https://opendht.net
  • Flags are similar to those of Dhtnode
  • -D enables the multicast automatic local peer discovery mechanism

Command Line Interface

  • c {channel} to join a channel
  • d to disconnect the channel
  • e {target} {message} to send an encrypted message to a specific user with public key ID

Demo

  • Create chat node 
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    zhiqich@ubuntu:~/Documents/opendht$ dhtchat -D
    OpenDHT node 1f04c73f6c5af467cd68ba4058a065bc0731ac19 running on port 59537
    Public key ID ecd52bfcb037b225e9021d5149a84a17eb881f4b
      type 'c {hash}' to join a channel
  • Join channel 
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    > c test
    Joining h(test) = a94a8fe5ccb19ba61c4c0873d391e987982fbbd3
  • Chat 
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    >> hi
    >> d108ebdc3f238876e94e59d6214ab465d644b460 at 2021-02-10 23:09:59 (took 0.811252s) : 10835693456077075259 - hi