Class: Sloth::Snmp

Inherits:
Object
  • Object
show all
Defined in:
lib/sloth/snmp/impl.rb,
lib/sloth/snmp/version.rb

Defined Under Namespace

Classes: Error, UDPTransportExt

Constant Summary collapse

VERSION = 
"0.1.0"

Instance Method Summary collapse

Constructor Details

#initialize(mibs: nil, bind: nil, rocommunity: "public", rwcommunity: "private") ⇒ Snmp

Returns a new instance of Snmp.



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# File 'lib/sloth/snmp/impl.rb', line 22

def initialize( mibs: nil, bind: nil, rocommunity: "public", rwcommunity: "private" )
  case  bind
  when  Integer, NilClass
    @host  =  "0.0.0.0"
    @port  =  bind || 162
  when  String
    host, port  =  bind.split(':')    rescue  nil
    if host.nil? || host.empty?
      @host  =  "0.0.0.0"
    else
      @host  =  host
    end
    if port.nil? || port.empty?
      @port  =  162
    else
      @port  =  port.to_i
    end
  else
    raise  Sloth::Snmp::Error, "invalid class. : %s" % bind.class
  end
  @rocommunity  =  rocommunity
  @rwcommunity  =  rwcommunity

  @mibs  =  SNMP::MIB.new
  @mibs.load_module( "RFC1155-SMI" )
  @mibs.load_module( "RFC1158-MIB" )

  case  mibs
  when  NilClass
    mibs  =  []
  when  Array
    # noop
  when  String
    mibs  =  [mibs]
  else
    raise  Sloth::Snmp::Error, "invalid class. : %s" % mibs.class
  end

  mibpath  =  mibs.shift
  while  mibpath
    mibbase  =  File.basename( mibpath )
    mibdir  =  File.dirname( mibpath )
    if ( mibdir == "." && mibbase == mibpath )
      @mibs.load_module( mibbase.gsub( /\..*\Z/, "" ) )
    else
      @mibs.load_module( mibbase.gsub( /\..*\Z/, "" ), mibdir )
    end
    mibpath  =  mibs.shift
  end

  @topics  =  {}
  @mutex  =  ::Mutex.new
end

Instance Method Details

#build_varbind(topic, type, value) ⇒ Object 



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# File 'lib/sloth/snmp/impl.rb', line 283

def build_varbind( topic, type, value )
  oid  =  SNMP::ObjectId.new( topic )  rescue  @mibs.oid( topic )
  case  type
  when  SNMP::OctetString
    SNMP::VarBind.new( oid, SNMP::OctetString.new( value ))
  when  SNMP::Integer
    SNMP::VarBind.new( oid, SNMP::Integer.new( value ))
  when  SNMP::Counter32
    SNMP::VarBind.new( oid, SNMP::Counter32.new( value ))
  when  SNMP::IpAddress
    SNMP::VarBind.new( oid, SNMP::IpAddress.new( value ))
  when  SNMP::ObjectId
    SNMP::VarBind.new( oid, SNMP::ObjectId.new( value ))
  else
    SNMP::VarBind.new( oid, SNMP::OctetString.new( value.to_s ))
  end
end

#get(peer, topics, **options) ⇒ Object 



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# File 'lib/sloth/snmp/impl.rb', line 136

def get( peer, topics, **options )
  host, port  =  peer.split(':')  rescue  nil
  host  =  "127.0.0.1"    if  host.nil? || host.empty?
  port  =  (port || 161).to_i
  community  =  options[:rocommunity]  ||  @rocommunity

  case  topics
  when  String
    oids  =  [ ( SNMP::ObjectId.new( topics )  rescue  @mibs.oid( topics ) ) ]
  when  Array
    oids  =  topics.map do |topic|
      SNMP::ObjectId.new( topic )  rescue  @mibs.oid( topic )
    end
  else
    raise  Sloth::Snmp::Error, "topics missing."
  end

  if  options[:bindto] && options[:device]
    transport  =  UDPTransportExt.new( Socket::AF_INET, bindto: options[:bindto], device: options[:device] )
  end

  manager  =  SNMP::Manager.new( host: host, port: port, community: community, transport: transport )

  items  =  {}
  begin
    response  =  Thread.handle_interrupt( ::Timeout::Error => :on_blocking ) do
      manager.get( oids )
    end

    response.each_varbind do |varbind|
      oid, item  =  * parse_varbind( varbind )
      items[oid]  =  item
    end

  rescue  SNMP::RequestTimeout => e
    raise  Sloth::Snmp::Error, e.message

  rescue  => e
    raise  Sloth::Snmp::Error, e.message

  end
  items
end

#parse_varbind(varbind, keys: nil) ⇒ Object 



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# File 'lib/sloth/snmp/impl.rb', line 245

def parse_varbind( varbind, keys: nil )
  keys  =  [:name, :value]    if keys.nil? || keys.empty?
  oid   =  varbind.name.to_str
  name  =  @mibs.name( oid )
  case  varbind.value
  when  SNMP::OctetString
    type  =  SNMP::OctetString
    valu  =  varbind.value.to_s
    if  /[^[:print:]]/.match( valu )
      valu  =  "0x" + valu.unpack("H*").shift
    end
  when  SNMP::Integer
    type  =  SNMP::Integer
    valu  =  varbind.value.to_i
  when  SNMP::Counter32
    type  =  SNMP::Counter32
    valu  =  varbind.value.to_i
  when  SNMP::IpAddress
    type  =  SNMP::IpAddress
    valu  =  varbind.value.to_s
  when  SNMP::ObjectId
    type  =  SNMP::ObjectId
    valu  =  varbind.value
  when  SNMP::NoSuchInstance, SNMP::NoSuchObject
    type  =  varbind.value
    valu  =  nil
  else
    type  =  varbind.value
    valu  =  nil
  end

  tuple  =  {}
  tuple[:name]  =  name    if keys.include?( :name )
  tuple[:type]  =  type    if keys.include?( :type )
  tuple[:value]  =  valu    if keys.include?( :value )
  [oid, tuple]
end

#set(peer, tuple, **options) ⇒ Object 



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# File 'lib/sloth/snmp/impl.rb', line 214

def set( peer, tuple, **options )
  host, port  =  peer.split(':')  rescue  nil
  host  =  "127.0.0.1"    if  host.nil? || host.empty?
  port  =  (port || 161).to_i
  community  =  options[:rwcommunity]  ||  @rwcommunity

  if  options[:bindto] && options[:device]
    transport  =  UDPTransportExt.new( Socket::AF_INET, bindto: options[:bindto], device: options[:device] )
  end

  varbind  =  build_varbind( tuple[:topic], tuple[:type], tuple[:value] )

  manager  =  SNMP::Manager.new( host: host, port: port, community: community, transport: transport )

  begin
    response  =  Thread.handle_interrupt( ::Timeout::Error => :on_blocking ) do
      manager.set( varbind )
    end
    response

  rescue  SNMP::RequestTimeout => e
    raise  Sloth::Snmp::Error, e.message

  rescue  => e
    raise  Sloth::Snmp::Error, e.message

  ensure
    manager.close
  end
end

#start_listener ⇒ Object 



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# File 'lib/sloth/snmp/impl.rb', line 76

def start_listener
  @thread  ||=  Thread.start do
    listener  =  SNMP::TrapListener.new( host: @host, port: @port, community: @rocommunity ) do |manager|
      manager.on_trap_v2c do |mesg|
        begin
          next    if mesg.error_status  !=  :noError

          source_ip  =  mesg.source_ip
          trap_oid  =  mesg.trap_oid.join(".")
          trapname  =  @mibs.name( trap_oid )
          items  =  {}
          mesg.each_varbind do |varbind|
            oid, item  =  * parse_varbind( varbind )
            items[oid]  =  item
          end
          Thread.start do
            @mutex.synchronize do
              @topics[ trap_oid ]&.call( trapname, source_ip, items )
            end
          end

        rescue => e
          raise  Sloth::Snmp::Error, e.message

        end
      end
    end
    Thread.current[:listener]  =  listener
    listener.join
  end
end

#stop_listener ⇒ Object 



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# File 'lib/sloth/snmp/impl.rb', line 108

def stop_listener
  @mutex.synchronize do
    @topics.clear
    @thread[:listener].exit
    @thread  =  nil
  end
end

#trap(*topics, &block) ⇒ Object 



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# File 'lib/sloth/snmp/impl.rb', line 116

def trap( *topics, &block )
  @mutex.synchronize do
    topics.each do |topic|
      trap_oid  =  SNMP::ObjectId.new( topic )  rescue  @mibs.oid( topic )
      @topics[trap_oid.to_str]  =  block
    end
  end
  start_listener
end

#untrap(*topics) ⇒ Object 



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# File 'lib/sloth/snmp/impl.rb', line 126

def untrap( *topics )
  @mutex.synchronize do
    topics.each do |topic|
      trap_oid  =  SNMP::ObjectId.new( topic )  rescue  @mibs.oid( topic )
      @topics.delete( trap_oid.to_str )
    end
  end
  stop_listener    if @topics.empty?
end

#walk(peer, topic, **options) ⇒ Object 



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# File 'lib/sloth/snmp/impl.rb', line 180

def walk( peer, topic, **options )
  host, port  =  peer.split(':')  rescue  nil
  host  =  "127.0.0.1"    if  host.nil? || host.empty?
  port  =  (port || 161).to_i
  community  =  options[:rocommunity]  ||  @rocommunity

  if  options[:bindto] && options[:device]
    transport  =  UDPTransportExt.new( Socket::AF_INET, bindto: options[:bindto], device: options[:device] )
  end

  manager  =  SNMP::Manager.new( host: host, port: port, community: community, transport: transport )

  topic  ||=  "internet"
  base_oid  =  SNMP::ObjectId.new( topic )  rescue  @mibs.oid( topic )

  items  =  {}
  begin
    Thread.handle_interrupt( ::Timeout::Error => :on_blocking ) do
      manager.walk( base_oid ) do |varbind|
        oid, item  =  * parse_varbind( varbind )
        items[oid]  =  item
      end
    end

  rescue  SNMP::RequestTimeout => e
    raise  Sloth::Snmp::Error, e.message

  rescue  => e
    raise  Sloth::Snmp::Error, e.message

  end
  items
end