module NetlinkProcEvent

This file is part of the ruby netlink_proc_event gem. It is subject to the license terms in the LICENSE file found in the top-level directory of this distribution and at github.com/christopheraue/netlink_proc_event.

Constants

VERSION

Attributes

logger[RW]

Public Class Methods

handle_events() click to toggle source

# File lib/netlink_proc_event.rb, line 21
def handle_events
  nl_sockaddr = FFI::MemoryPointer.new(32)
  ptr_to_msg_ptr = FFI::MemoryPointer.new(:pointer)

  msg_length = Libnl.nl_recv(nl_socket, nl_sockaddr, ptr_to_msg_ptr, nil)
  msg_ptr = ptr_to_msg_ptr.read_pointer
  msg_valid = Libnl.nlmsg_ok(msg_ptr, msg_length) > 0

  if msg_length > 0 && msg_ptr && msg_valid
    msg_payload_ptr = Libnl.nlmsg_data(msg_ptr)
    msg_payload = Libnl::ProcEvent.new(msg_payload_ptr)
    handle_event(msg_payload)
  end
end

off(event, handler) click to toggle source

# File lib/netlink_proc_event.rb, line 44
def off(event, handler)
  check_event(event)
  return unless event_handlers[event]
  event_handlers[event].delete(handler)
  event_handlers.delete(event) if event_handlers[event].empty?
end

on(event, &handler) click to toggle source

# File lib/netlink_proc_event.rb, line 36
def on(event, &handler)
  check_event(event)
  subscribe_to_proc_events
  event_handlers[event] ||= []
  event_handlers[event] << handler
  handler
end

socket() click to toggle source

# File lib/netlink_proc_event.rb, line 17
def socket
  UNIXSocket.for_fd(Libnl.nl_socket_get_fd(nl_socket))
end

Private Class Methods

check_event(event) click to toggle source

# File lib/netlink_proc_event.rb, line 68
def check_event(event)
  Libnl::Event[event] || raise("Unknown event #{event}.")
end

event_handlers() click to toggle source

# File lib/netlink_proc_event.rb, line 64
def event_handlers
  @event_handlers ||= {}
end

handle_event(event) click to toggle source

# File lib/netlink_proc_event.rb, line 91
def handle_event(event)
  if event_handlers[event[:what]]
    type = event[:what].to_s.split('_').last.downcase.to_sym
    event_handlers[event[:what]].each{ |handler| handler.call(event[:event_data][type]) }
    true
  else
    false
  end
end

nl_socket() click to toggle source

# File lib/netlink_proc_event.rb, line 53
def nl_socket
  @nl_socket ||= Libnl.nl_socket_alloc.tap do |socket|
    Libnl.nl_socket_disable_seq_check(socket)
    Libnl.nl_join_groups(socket, Libnl::CN_IDX_PROC)
    Libnl.log(@logger, "Netlink connection attempt", Libnl.nl_connect(socket, Libnl::NETLINK_CONNECTOR))
    Libnl.nl_socket_disable_auto_ack(socket)
    Libnl.nl_socket_disable_seq_check(socket)
    Libnl.nl_socket_enable_msg_peek(socket)
  end
end

subscribe_to_proc_events() click to toggle source

# File lib/netlink_proc_event.rb, line 72
def subscribe_to_proc_events
  return if @subscribed_to_proc_events

  msg = Libnl.nlmsg_alloc_simple(Libnl::NLMSG_DONE, 0)
  data = Libnl.nlmsg_reserve(msg, 24, 4)

  proc_message = Libnl::CnMsg.new(data)
  proc_message[:idx] = Libnl::CN_IDX_PROC
  proc_message[:val] = Libnl::CN_VAL_PROC
  proc_message[:data] = 1
  proc_message[:len] = 4 # Contains an int
  proc_message[:seq] = 0
  proc_message[:ack] = 0

  Libnl.log(@logger, "Netlink subscribed to proc events", Libnl.nl_send_auto(nl_socket, msg), 'Success')

  @subscribed_to_proc_events = true
end