Hosting your own XFTP Server

Overview

XFTP is a new file transfer protocol focussed on meta-data protection - it is based on the same principles as SimpleX Messaging Protocol used in SimpleX Chat messenger:

  • asynchronous file delivery - the sender does not need to be online for file to be received, it is stored on XFTP relays for a limited time (currently, it is 48 hours) or until deleted by the sender.
  • padded e2e encryption of file content.
  • content padding and fixed size chunks sent via different XFTP relays, assembled back into the original file by the receiving client.
  • efficient sending to multiple recipients (the file needs to be uploaded only once).
  • no identifiers or ciphertext in common between sent and received relay traffic, same as for messages delivered by SMP relays.
  • protection of sender IP address from the recipients.

Installation

  1. First, install xftp-server:

Manual installation requires some preliminary actions:

  1. Install binary:

    • Using offical binaries:

      curl -L https://github.com/simplex-chat/simplexmq/releases/latest/download/xftp-server-ubuntu-20_04-x86-64 -o /usr/local/bin/xftp-server && chmod +x /usr/local/bin/xftp-server
      
    • Compiling from source:

      Please refer to Build from source: Using your distribution

  2. Create user and group for xftp-server:

    sudo useradd -m xftp
    
  3. Create necessary directories and assign permissions:

    sudo mkdir -p /var/opt/simplex-xftp /etc/opt/simplex-xftp /srv/xftp
    sudo chown xftp:xftp /var/opt/simplex-xftp /etc/opt/simplex-xftp /srv/xftp
    
  4. Allow xftp-server port in firewall:

    # For Ubuntu
    sudo ufw allow 443/tcp
    # For Fedora
    sudo firewall-cmd --permanent --add-port=443/tcp && \
    sudo firewall-cmd --reload
    
  5. Optional — If you're using distribution with systemd, create /etc/systemd/system/xftp-server.service file with the following content:

    [Unit]
    Description=XFTP server systemd service
    
    [Service]
    User=xftp
    Group=xftp
    Type=simple
    ExecStart=/usr/local/bin/xftp-server start +RTS -N -RTS
    ExecStopPost=/usr/bin/env sh -c '[ -e "/var/opt/simplex-xftp/file-server-store.log" ] && cp "/var/opt/simplex-xftp/file-server-store.log" "/var/opt/simplex-xftp/file-server-store.log.$(date +'%FT%T')"'
    LimitNOFILE=65535
    KillSignal=SIGINT
    TimeoutStopSec=infinity
    AmbientCapabilities=CAP_NET_BIND_SERVICE
       
    [Install]
    WantedBy=multi-user.target
    

    And execute sudo systemctl daemon-reload.

Tor installation

xftp-server can also be deployed to serve from tor network. Run the following commands as root user.

  1. Install tor:

    We're assuming you're using Ubuntu/Debian based distributions. If not, please refer to offical tor documentation or your distribution guide.

    • Configure offical Tor PPA repository:

      CODENAME="$(lsb_release -c | awk '{print $2}')"
      echo "deb [signed-by=/usr/share/keyrings/tor-archive-keyring.gpg] https://deb.torproject.org/torproject.org ${CODENAME} main
      deb-src [signed-by=/usr/share/keyrings/tor-archive-keyring.gpg] https://deb.torproject.org/torproject.org ${CODENAME} main" > /etc/apt/sources.list.d/tor.list
      
    • Import repository key:

      curl --proto '=https' --tlsv1.2 -sSf https://deb.torproject.org/torproject.org/A3C4F0F979CAA22CDBA8F512EE8CBC9E886DDD89.asc | gpg --dearmor | tee /usr/share/keyrings/tor-archive-keyring.gpg >/dev/null
      
    • Update repository index:

      apt update
      
    • Install tor package:

      apt install -y tor deb.torproject.org-keyring
      
  2. Configure tor:

    • File configuration:

      Open tor configuration with your editor of choice (nano,vim,emacs,etc.):

      vim /etc/tor/torrc
      

      And insert the following lines to the bottom of configuration. Please note lines starting with #: this is comments about each individual options.

      # Enable log (otherwise, tor doesn't seemd to deploy onion address)
      Log notice file /var/log/tor/notices.log
      # Enable single hop routing (2 options below are dependencies of third). Will reduce latency in exchange of anonimity (since tor runs alongside xftp-server and onion address will be displayed in clients, this is totally fine)
      SOCKSPort 0
      HiddenServiceNonAnonymousMode 1
      HiddenServiceSingleHopMode 1
      # xftp-server hidden service host directory and port mappings
      HiddenServiceDir /var/lib/tor/simplex-xftp/
      HiddenServicePort 443 localhost:443
      
    • Create directories:

      mkdir /var/lib/tor/simplex-xftp/ && chown debian-tor:debian-tor /var/lib/tor/simplex-xftp/ && chmod 700 /var/lib/tor/simplex-xftp/
      
  3. Start tor:

    Enable systemd service and start tor. Offical tor is a bit flunky on the first start and may not create onion host address, so we're restarting it just in case.

    systemctl enable tor && systemctl start tor && systemctl restart tor
    
  4. Display onion host:

    Execute the following command to display your onion host address:

    cat /var/lib/tor/simplex-xftp/hostname
    

Configuration

To see which options are available, execute xftp-server without flags:

sudo su xftp -c xftp-server

...
Available commands:
  init                     Initialize server - creates /etc/opt/simplex-xftp and
                           /var/opt/simplex-xftp directories and configuration
                           files
  start                    Start server (configuration:
                           /etc/opt/simplex-xftp/file-server.ini)
  delete                   Delete configuration and log files

You can get further help by executing su xftp -c "xftp-server <command> -h"

After that, we need to configure xftp-server:

sudo su xftp -c "xftp-server init -h"

...
Available options:
  -l,--store-log           Enable store log for persistence
  -a,--sign-algorithm ALG  Signature algorithm used for TLS certificates:
                           ED25519, ED448 (default: ED448)
  --ip IP                  Server IP address, used as Common Name for TLS online
                           certificate if FQDN is not supplied
                           (default: "127.0.0.1")
  -n,--fqdn FQDN           Server FQDN used as Common Name for TLS online
                           certificate
  -p,--path PATH           Path to the directory to store files
  -q,--quota QUOTA         File storage quota (e.g. 100gb)
  -h,--help                Show this help text

You should determine which flags are needed for your use-case and then execute xftp-server init:

sudo su xftp -c "xftp-server init -<your flag> <your option>"

For example, run:

sudo su xftp -c "xftp-server init -l --ip 192.168.1.5 -q '20gb' -p /srv/xftp/"

to initialize your xftp-server configuration with:

  • restoring connections when the server is restarted (-l flag),
  • IP address 192.168.1.5 (--ip flag),
  • set overall storage quota to 10Gb (-q flag),
  • store files in /srv/xftp directory (-p flag).

To password-protect your xftp-server, change it in the configuration:

  1. Open configuration with:

    sudo su xftp -c "vim /etc/opt/simplex-xftp/file-server.ini"
    
  2. Under [AUTH] section uncomment create_password and change it:

    ...
    [AUTH]
    # Set new_files option to off to completely prohibit uploading new files.
    # This can be useful when you want to decommission the server, but still allow downloading the existing files.
    new_files: on
    
    # Use create_password option to enable basic auth to upload new files.
    # The password should be used as part of server address in client configuration:
    # xftp://fingerprint:password@host1,host2
    # The password will not be shared with file recipients, you must share it only
    # with the users who you want to allow uploading files to your server.
    create_password: your_very_secure_password
    ...
    

After that, your installation is complete and you should see in your teminal output something like this:

Certificate request self-signature ok
subject=CN = 192.168.1.5
Server initialized, you can modify configuration in /etc/opt/simplex-xftp/file-server.ini.
Run `file-server start` to start server.
----------
You should store CA private key securely and delete it from the server.
If server TLS credential is compromised this key can be used to sign a new one, keeping the same server identity and established connections.
CA private key location:
/etc/opt/simplex-xftp/ca.key
----------
SimpleX XFTP server v0.1.0
Fingerprint: ioyYeRyy4SqJkNvb_7nM04MuLasOM4c-acVyVnqw248=
Server address: xftp://ioyYeRyy4SqJkNvb_7nM04MuLasOM4c-acVyVnqw248=@<hostnames>

The server address above should be used in your client configuration and if you added server password it should only be shared with the other people when you want to allow them to use your server to upload files. If you passed IP address or hostnames during the initialisation, they will be printed as part of server address, otherwise replace <hostnames> with the actual server addresses.

Documentation

All necessary files for xftp-server are located in /etc/opt/simplex-xftp/ folder.

Stored messages, connections, statistics and server log are located in /var/opt/simplex-xftp/ folder.

Location of uploaded files is configured by the user. In our guide we're using /srv/xftp/

XFTP server address

XFTP server address has the following format:

xftp://<fingerprint>[:<password>]@<public_hostname>[,<onion_hostname>]
  • <fingerprint>

    Your xftp-server fingerprint of certificate. You can check your certificate fingerprint in /etc/opt/simplex-xftp/fingerprint.

  • optional <password>

    Your configured password of xftp-server. You can check your configured pasword in /etc/opt/simplex-xftp/file-server.ini, under [AUTH] section in create_password: field.

  • <public_hostname>, optional <onion_hostname>

    Your configured hostname(s) of xftp-server. You can check your configured hosts in /etc/opt/simplex-xftp/file-server.ini, under [TRANSPORT] section in host: field.

Systemd commands

To start xftp-server on host boot, run:

sudo systemctl enable xftp-server.service

Created symlink /etc/systemd/system/multi-user.target.wants/xftp-server.service → /etc/systemd/system/xftp-server.service.

To start xftp-server, run:

sudo systemctl start xftp-server.service

To check status of xftp-server, run:

sudo systemctl status xftp-server.service

● xftp-server.service - XFTP server systemd service
     Loaded: loaded (/etc/systemd/system/xftp-server.service; enabled; vendor preset: enabled)
     Active: active (running) since Sat 2023-03-11 13:11:55 UTC; 1 months 10 days ago
   Main PID: 110770 (xftp-server)
      Tasks: 14 (limit: 4611)
     Memory: 2.4G
     CGroup: /system.slice/xftp-server.service
             └─110770 /usr/local/bin/xftp-server start +RTS -N -RTS

Feb 27 19:21:11 localhost systemd[1]: Started XFTP server systemd service.
Feb 27 19:21:11 localhost xftp-server[2350]: SimpleX XFTP server v0.1.0
Feb 27 19:21:11 localhost xftp-server[2350]: Fingerprint: ioyYeRyy4SqJkNvb_7nM04MuLasOM4c-acVyVnqw248=
Feb 27 19:21:11 localhost xftp-server[2350]: Server address: xftp://ioyYeRyy4SqJkNvb_7nM04MuLasOM4c-acVyVnqw248=@<hostnames>
Feb 27 19:21:11 localhost xftp-server[2350]: Store log: /var/opt/simplex-xftp/file-server-store.log
Feb 27 19:21:11 localhost xftp-server[2350]: Uploading new files allowed.
Feb 27 19:21:11 localhost xftp-server[2350]: Listening on port 443...
Feb 27 19:21:11 localhost xftp-server[2350]: [INFO 2023-02-27 19:21:11 +0000 src/Simplex/FileTransfer/Server/Env.hs:85] Total / available storage: 64424509440 / 64424509440

To stop xftp-server, run:

sudo systemctl stop xftp-server.service

To check tail of xftp-server log, run:

sudo journalctl -fu xftp-server.service

Feb 27 19:21:11 localhost systemd[1]: Started XFTP server systemd service.
Feb 27 19:21:11 localhost xftp-server[2350]: SimpleX XFTP server v0.1.0
Feb 27 19:21:11 localhost xftp-server[2350]: Fingerprint: ioyYeRyy4SqJkNvb_7nM04MuLasOM4c-acVyVnqw248=
Feb 27 19:21:11 localhost xftp-server[2350]: Server address: xftp://ioyYeRyy4SqJkNvb_7nM04MuLasOM4c-acVyVnqw248=@<hostnames>
Feb 27 19:21:11 localhost xftp-server[2350]: Store log: /var/opt/simplex-xftp/file-server-store.log
Feb 27 19:21:11 localhost xftp-server[2350]: Uploading new files allowed.
Feb 27 19:21:11 localhost xftp-server[2350]: Listening on port 443...
Feb 27 19:21:11 localhost xftp-server[2350]: [INFO 2023-02-27 19:21:11 +0000 src/Simplex/FileTransfer/Server/Env.hs:85] Total / available storage: 64424509440 / 64424509440

Monitoring

You can enable xftp-server statistics for Grafana dashboard by setting value on in /etc/opt/simplex-xftp/file-server.ini, under [STORE_LOG] section in log_stats: field.

Logs will be stored as csv file in /var/opt/simplex-xftp/file-server-stats.daily.log. Fields for the csv file are:

fromTime,filesCreated,fileRecipients,filesUploaded,filesDeleted,dayCount,weekCount,monthCount,fileDownloads,fileDownloadAcks,filesCount,filesSize
  • fromTime - timestamp; date and time of event

  • filesCreated - int; chunks created

  • fileRecipients - int; number of file chunks recipients

  • filesUploaded - int; chunks uploaded

  • filesDeleted - int; chunks deleted

  • dayCount - int; uploaded chunks in a day

  • weekCount - int; uploaded chunks in a week

  • monthCount - int; uploaded chunks in a month

  • fileDownloads - int; chunks downloaded

  • filesCount - int; count of stored file chunks

  • filesSize - int; total size of uploaded file chunks

To import csv to Grafana one should:

  1. Install Grafana plugin: Grafana - CSV datasource

  2. Allow local mode by appending following:

    [plugin.marcusolsson-csv-datasource]
    allow_local_mode = true
    

    ... to /etc/grafana/grafana.ini

  3. Add a CSV data source:

    • In the side menu, click the Configuration tab (cog icon)
    • Click Add data source in the top-right corner of the Data Sources tab
    • Enter "CSV" in the search box to find the CSV data source
    • Click the search result that says "CSV"
    • In URL, enter a file that points to CSV content
  4. You're done! You should be able to create your own dashboard with statistics.

For further documentation, see: CSV Data Source for Grafana - Documentation

Updating your XFTP server

To update your XFTP server to latest version, choose your installation method and follow the steps:

  • Manual deployment

    1. Stop the server:
      sudo systemctl stop xftp-server
      
    2. Update the binary:
       curl -L https://github.com/simplex-chat/simplexmq/releases/latest/download/xftp-server-ubuntu-20_04-x86-64 -o /usr/local/bin/xftp-server && chmod +x /usr/local/bin/xftp-server
      
    3. Start the server:
      sudo systemctl start xftp-server
      
  • Offical installation script

    1. Execute the followin command:
      sudo simplex-servers-update
      
    2. Done!
  • Docker container

    1. Stop and remove the container:
      docker rm $(docker stop $(docker ps -a -q --filter ancestor=simplexchat/xftp-server --format="\{\{.ID\}\}"))
      
    2. Pull latest image:
      docker pull simplexchat/xftp-server:latest
      
    3. Start new container:
      docker run -d \
        -p 443:443 \
        -v $HOME/simplex/xftp/config:/etc/opt/simplex-xftp:z \
        -v $HOME/simplex/xftp/logs:/var/opt/simplex-xftp:z \
        -v $HOME/simplex/xftp/files:/srv/xftp:z \
        simplexchat/xftp-server:latest
      
  • Linode Marketplace

    1. Pull latest images:
      docker-compose --project-directory /etc/docker/compose/simplex pull
      
    2. Restart the containers:
      docker-compose --project-directory /etc/docker/compose/simplex up -d --remove-orphans
      
    3. Remove obsolete images:
      docker image prune
      

Configuring the app to use the server

Please see: SMP Server: Configuring the app to use the server.

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