adsb-tools/adsbus

adsbus

adsbus is a hub and protocol translator for ADS-B messages.

It is conceptually similar to dump1090 --net-only, but supports more protocols and configurations. It doesn't talk to your radio itself; it hooks programs that do, then handles the network distribution and format translation. It doesn't output to a web interface or send data to services like FlightAware; it provides hooks for programs that do.

Building

sudo apt-get -y install build-essential git clang libjansson-dev libprotobuf-c-dev protobuf-c-compiler
git clone https://github.com/flamingcowtv/adsb-tools.git
cd adsb-tools/adsbus
make

Features

• Separates the concepts of transport, data flow, and format
• Transports:
  • Outgoing TCP connection
  • Incoming TCP connection
  • Local files, named pipes, and character devices
  • stdin/stdout
  • Execute a command and talk to its stdin/stdout, proxy logs from its stderr
• Data flows:
  • Send (data flows out of adsbus)
  • Receive (data flows in to adsbus)
  • Send & receive (both directions on the same socket, without echo)
• Formats:
  • airspy_adsb (a.k.a. ASAVR)
  • beast
  • json
  • proto (a.k.a. ProtoBuf, Protocol Buffers)
  • raw (a.k.a. AVR)
  • stats (send only, summary aggregated data)
• Transport features:
  • IPv4 and IPv6 support
  • Reresolution and reconnection on disconnect, with backoff and jitter
  • TCP keepalives for dead connection detection
  • TCP fast open for faster startup of high-latency connections
  • SO_REUSEPORT for zero-downtime updates
• Data flow features:
  • Rapid detection and disconnection of receive <-> receive connections
  • Less rapid detection and disconnection of send <-> send connections
  • Hop counting and limits (json and proto formats only) to stop infinite routing loops
• Format features:
  • Autodetection of received data format
  • MLAT scaling for different clock rates and counter bit widths
  • RSSI scaling for different bit widths
  • Introduces json format for balanced human and machine readability with forward compatibility
  • Introduces proto format for fast serialization and deserialization with forward compatibility
• Federation:
  • Federation allows linking multiple instances of adsbus for:
    • Scalability (cores, number of input or output clients, etc.)
    • Efficient long-haul links (hub and spoke models on both ends)
  • json and proto formats carry information about original source across multiple hops
  • SO_REUSEPORT allows multiple adsbus instances to accept connections on the same IP and port without a load balancer

Use

• As a commandline utility
  • For captures from a network source:

    $ ./adsbus --quiet --connect-receive=10.66.0.75/30005 --file-write=beast=dump.beast
    ^C
    $ ls -l dump.beast
    -rw------- 1 flamingcow flamingcow 4065 Mar 11 15:07 dump.beast
    

  • For file type conversion:

    $ ./adsbus --quiet --file-read=dump.beast --file-write=proto=dump.proto
    $ ls -l dump.*
    -rw------- 1 flamingcow flamingcow  4065 Mar 11 15:07 dump.beast
    -rw------- 1 flamingcow flamingcow 16548 Mar 11 15:10 dump.proto
    

  • For examining file contents:

    ./adsbus --quiet --file-read=dump.proto --stdout=json
    {"type": "header", "server_version": "https://github.com/flamingcowtv/adsb-tools#1", "magic": "aDsB", "server_id": "0cd53a31-e62f-4c89-a969-cf0e0f7b141a", "rssi_max": 4294967295, "mlat_timestamp_mhz": 120, "mlat_timestamp_max": 9223372036854775807}
    {"payload": "200016171BA2BB", "hops": 2, "mlat_timestamp": 370512307133580, "type": "Mode-S short", "source_id": "237e62d7-9f77-4ee0-9025-33367f5f2fc6", "rssi": 286331153}
    {"payload": "5D400D30A969AA", "hops": 2, "mlat_timestamp": 370512308420280, "type": "Mode-S short", "source_id": "237e62d7-9f77-4ee0-9025-33367f5f2fc6", "rssi": 858993459}
    {"payload": "5DAAC189CD820A", "hops": 2, "mlat_timestamp": 370512310040460, "type": "Mode-S short", "source_id": "237e62d7-9f77-4ee0-9025-33367f5f2fc6", "rssi": 640034342}
    {"payload": "59A528D6148686", "hops": 2, "mlat_timestamp": 370512310059540, "type": "Mode-S short", "source_id": "237e62d7-9f77-4ee0-9025-33367f5f2fc6", "rssi": 218959117}
    {"payload": "5DAAC189CD820A", "hops": 2, "mlat_timestamp": 370512312373740, "type": "Mode-S short", "source_id": "237e62d7-9f77-4ee0-9025-33367f5f2fc6", "rssi": 673720360}
    ...
    

Security, reliability, testing

• Secure build options by default
  • -Weverything -Werror -pedantic-errors (with limited specific exceptions)
  • -D_FORTIFY_SOURCE=2
  • -fstack-protector-strong
  • -fPIE -pie
  • -z relro
  • -z now
• valgrind clean
  • Zero open fds and allocated blocks when run with --track-fds=yes --show-leak-kinds=all --leak-check=full
  • Cleans up on normal exit and when handling SIGINT/SIGTERM
• Subprogram isolation
  • All fds created with CLOEXEC; none passed on to children (tested with --exec-receive='ls -l /proc/self/fd 1>&2')
  • Separate process group
• Test suite
  • make test runs a large set of test inputs through adsbus under valgrind
• Parser fuzzing
  • make afl-fuzz runs adsbus inside american fuzzy lop starting from previous output cases
• Network fuzzing
  • stutterfuzz.sh runs adsbus with stutterfuzz to test connection/network handling under load, using afl test cases