Class: Ethernet::RawSocketFactory::BpfSocketWrapper

Inherits:
Object
  • Object
show all
Defined in:
lib/ethernet/raw_socket_factory_darwin.rb

Overview

Wraps a BPF file descriptor into a socket-like interface.

Instance Method Summary collapse

Constructor Details

#initialize(bpf) ⇒ BpfSocketWrapper

Creates a wrapper for a BPF file descriptor.



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# File 'lib/ethernet/raw_socket_factory_darwin.rb', line 130

def initialize(bpf)
  @bpf = bpf
  @read_size = read_buffer_length
  @queue = []
end

Instance Method Details

#close ⇒ Object

Implements Socket#close.



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# File 'lib/ethernet/raw_socket_factory_darwin.rb', line 160

def close
  @bpf.close
end

#recv(buffer_size) ⇒ Object

Implements Socket#recv.



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# File 'lib/ethernet/raw_socket_factory_darwin.rb', line 137

def recv(buffer_size)
  while @queue.empty?
    read_buffer = @bpf.sysread @read_size
    bytes_read = read_buffer.length
    offset = 0
    while offset < bytes_read
      # struct bpf_hdr in /usr/include/net/bpf.h
      timestamp, captured_size, original_size, header_size =
          *read_buffer.unpack('QLLS')
      @queue.push read_buffer[header_size, captured_size]
      # BPF_WORDALIGN in /usr/include/net/bpf.h
      offset += (header_size + captured_size + 3) & 0xFFF4
    end
  end
  @queue.shift
end

#send(buffer, flags) ⇒ Object

Implements Socket#send.



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# File 'lib/ethernet/raw_socket_factory_darwin.rb', line 155

def send(buffer, flags)
  @bpf.write buffer
end