69 lines
1.7 KiB
Lua
69 lines
1.7 KiB
Lua
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-- source the lib file with the function
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dofile("rns-lib.lua")
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-- echo whatever is received
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-- this function disfigures the packet
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function lua_packet_mangle(orig_packet)
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-- MANGLE IT
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local rr1 = record.new_frm_str("www.miek.nl IN A 127.0.0.1")
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packet.push_rr(orig_packet, LDNS_SECTION_ANSWER, rr1)
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return(packet.to_buf(orig_packet))
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end
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rdf_ip = rdf.new_frm_str(LDNS_RDF_TYPE_A, "127.0.0.1")
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socket = udp.server_open(rdf_ip, 5353)
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if socket == nil then
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os.exit(EXIT_FAILURE)
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end
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rdf_ip_nameserver = rdf.new_frm_str(LDNS_RDF_TYPE_A, "213.154.224.39")
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while true do
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-- read from the socket, this blocks...
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wirebuf, sockaddr_from = udp.read(socket)
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-- wrap this in new functions
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if wirebuf == nil then
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lua_debug("nothing received")
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else
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-- somebody is writing
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wirepkt = buffer.to_pkt(wirebuf)
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packet.print(wirepkt)
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wirebuf2 = packet.to_buf(wirepkt)
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-- send it to /our/ nameserver
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socket_nameserver = udp.open(rdf_ip_nameserver, 53)
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if socket_nameserver == nil then
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os.exit(EXIT_FAILURE)
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end
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nameserver_bytes = udp.write(socket_nameserver, wirebuf2, rdf_ip_nameserver, 53)
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if nameserver_bytes == nil then
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lua_debug("ns write error")
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end
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nameserver_buf, sockaddr_from_nameserver = udp.read(socket_nameserver)
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udp.close(socket_nameserver)
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nameserver_pkt = buffer.to_pkt(nameserver_buf)
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packet.print(nameserver_pkt)
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-- make a new buf and write that back to the client
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nsbuf2 = lua_packet_mangle(nameserver_pkt)
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bytes = lua_udp_write(socket, nsbuf2, sockaddr_from) --this works
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if bytes == nil then
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lua_debug("write error")
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end
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buffer.free(nsbuf2)
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buffer.free(nameserver_buf)
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buffer.free(wirebuf2)
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buffer.free(wirebuf)
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end
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end
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udp.close(socket)
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