Module: Raptor::ReuseportBPF

Defined in:
lib/raptor/reuseport_bpf.rb,
sig/generated/raptor/reuseport_bpf.rbs

Overview

Routes incoming connections across worker processes to the worker with the lowest reactor backlog.

Auto-enabled on Linux when the libbpf-ruby gem is installed and the BPF object file has been compiled. Falls back silently to standard SO_REUSEPORT when either is missing. Raises when the kernel refuses the BPF program. Wraps tcp:// bindings only; non-tcp bindings are left to the binder's shared listeners.

Constant Summary collapse

LIBBPF_LOADED =

Returns:

  • (Object) 
!!defined?(LibBPFRuby)
BPF_OBJECT_PATH =

Returns:

  • (Object) 
File.expand_path("../../ext/raptor_bpf/reuseport_select.bpf.o", __dir__)

Class Method Summary collapse

Class Method Details

.create_worker_listeners(bind_uris, worker_index, socket_backlog) ⇒ Array<TCPServer>

Returns tcp listening sockets bound and registered for worker_index. Skips non-tcp bind URIs.

Parameters:

  • bind_uris (Array<String>) —

    the configured bind URIs

  • worker_index (Integer) —

    slot index for this worker in the socks map

  • socket_backlog (Integer) —

    kernel listen() queue depth

Returns:

  • (Array<TCPServer>) —

    the tcp listening sockets created for this worker



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# File 'lib/raptor/reuseport_bpf.rb', line 67

def self.create_worker_listeners(bind_uris, worker_index, socket_backlog)
  @load_key = [worker_index + 1].pack("L")
  @load_value = String.new("\x00\x00\x00\x00", encoding: Encoding::ASCII_8BIT)

  bind_uris.filter_map do |bind_uri|
    uri = URI(bind_uri)
    next unless uri.scheme == "tcp"

    host = uri.host
    host = host[1..-2] if host&.start_with?("[")

    addrinfo = Addrinfo.tcp(host, uri.port)
    socket = Socket.new(addrinfo.afamily, Socket::SOCK_STREAM, 0)
    socket.setsockopt(Socket::SOL_SOCKET, Socket::SO_REUSEADDR, true)
    socket.setsockopt(Socket::SOL_SOCKET, Socket::SO_REUSEPORT, true)
    socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
    socket.bind(addrinfo)
    socket.listen(socket_backlog)

    LibBPFRuby.sockmap_update(@socks_fd, [worker_index].pack("L"), socket)
    LibBPFRuby.attach_reuseport(socket, @program_fd)

    tcp_server = TCPServer.for_fd(socket.fileno)
    socket.autoclose = false
    tcp_server
  end
end

.setup(worker_count) ⇒ Boolean

Prepares BPF-directed routing for worker_count workers.

Returns true when BPF-directed dispatch is active. Returns false when the platform is unsupported. Raises when the kernel refuses the program.

Parameters:

  • worker_count (Integer) —

    number of worker processes that will bind sockets

Returns:

  • (Boolean) 


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# File 'lib/raptor/reuseport_bpf.rb', line 46

def self.setup(worker_count)
  return false unless supported?

  @object = LibBPFRuby::Object.new(BPF_OBJECT_PATH)
  @program_fd = @object.program_fd("select_least_loaded")
  @socks_fd = @object.map_fd("socks")
  @loads_fd = @object.map_fd("loads")

  LibBPFRuby.map_update(@loads_fd, [0].pack("L"), [worker_count].pack("L"))
  true
end

.supported? ⇒ Boolean

Whether the preconditions for BPF-directed reuseport are met on this platform. Does not imply that the kernel will accept the program.

Returns:

  • (Boolean) 


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# File 'lib/raptor/reuseport_bpf.rb', line 32

def self.supported?
  LIBBPF_LOADED && File.exist?(BPF_OBJECT_PATH)
end

.update_load(backlog) ⇒ void

This method returns an undefined value.

Publishes this worker's current backlog to the BPF map.

Parameters:

  • backlog (Integer) —

    the worker's current reactor backlog



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# File 'lib/raptor/reuseport_bpf.rb', line 101

def self.update_load(backlog)
  @load_value.setbyte(0, backlog & 0xff)
  @load_value.setbyte(1, (backlog >> 8) & 0xff)
  @load_value.setbyte(2, (backlog >> 16) & 0xff)
  @load_value.setbyte(3, (backlog >> 24) & 0xff)
  LibBPFRuby.map_update(@loads_fd, @load_key, @load_value)
end