Class: Ping::TCP

Inherits:
Ping
  • Object
show all
Defined in:
lib/net/ping/tcp.rb

Overview

With a TCP ping simply try to open a connection. If we are successful, assume success. In either case close the connection to be polite.

Constant Summary collapse

@@service_check = 
false

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.service_check ⇒ Object Also known as: econnrefused, ecr

Returns whether or not Errno::ECONNREFUSED is considered a successful ping. The default is false.



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# File 'lib/net/ping/tcp.rb', line 15

def self.service_check
  @@service_check
end

.service_check=(bool) ⇒ Object Also known as: econnrefused=, ecr=

Sets whether or not an Errno::ECONNREFUSED should be considered a successful ping.



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# File 'lib/net/ping/tcp.rb', line 22

def self.service_check=(bool)
  unless bool.kind_of?(TrueClass) || bool.kind_of?(FalseClass)
    raise ArgumentError, 'argument must be true or false'
  end
  @@service_check = bool
end

Instance Method Details

#ping(host = @host) ⇒ Object

This method attempts to ping a host and port using a TCPSocket with the host, port and timeout values passed in the constructor. Returns true if successful, or false otherwise.

Note that, by default, an Errno::ECONNREFUSED return result will be considered a failed ping. See the documentation for the Ping::TCP.service_check= method if you wish to change this behavior.



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# File 'lib/net/ping/tcp.rb', line 37

def ping(host=@host)
  super(host)

  bool = false

  # Failure here most likely means bad host, so just bail.
  begin
    addr = Socket.getaddrinfo(host, port)
  rescue SocketError => err
    @exception = err
    return false
  end

  begin
    # Where addr[0][0] is likely AF_INET.
    sock = Socket.new(Socket.const_get(addr[0][0]), Socket::SOCK_STREAM, 0)

    # This may not be entirely necessary
    sock.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)

    start_time = Time.now

    begin
      # Where addr[0][3] is an IP address
      sock.connect_nonblock(Socket.pack_sockaddr_in(port, addr[0][3]))
    rescue Errno::EINPROGRESS
      # No-op, continue below
    rescue Exception => err
      # Something has gone horribly wrong
      @exception = err
      return false
    end

    resp = IO.select(nil, [sock], nil, timeout)

    if resp.nil? # Assume ECONNREFUSED if nil
      if @@service_check
        bool = true
      else
        bool = false
        @exception = Errno::ECONNREFUSED
      end
    else
      sockopt = sock.getsockopt(Socket::SOL_SOCKET, Socket::SO_ERROR)

      if sockopt.int != 0
        if @@service_check && sockopt.int == Errno::ECONNREFUSED::Errno
          bool = true
        else
          bool = false
          @exception = SystemCallError.new(sockopt.int)
        end
      else
        bool = true
      end
    end
  ensure
    sock.close if sock
  end

  # There is no duration if the ping failed
  @duration = Time.now - start_time if bool
end