ruby - Receive UDP datagram on raw socket? -

i'm trying write own implementation of udp in ruby educational purposes using raw sockets.

here's have far:

require 'socket'  addr = socket.pack_sockaddr_in(4567, '127.0.0.1')  socket = socket.new(   socket::pf_inet,   socket::sock_raw,   socket::ipproto_raw )  socket.bind(addr) socket.recvfrom(1024) 

i testing so:

require 'socket'  udp = udpsocket.new udp.send "hello world", 0, "127.0.0.1", 4567 

but call recvfrom blocking indefinitely.

if change this:

socket = socket.new(   socket::pf_inet,   socket::sock_dgram,   socket::ipproto_udp ) 

it of course works because system-level way accept udp packets.

how can receive udp packets on raw socket?
clear: want handle actual udp protocol (decoding datagram & doing checksum) myself!

raw sockets work @ ip level. cannot bind raw socket port. can bind local address bind or interface setting proper socket options (i don't know how in ruby, in c call setsockopt. instead of ipproto_raw should use ipproto_udp in protocol.you receive udp datagrams received on ip address or interface if socket bound it.