Basic handling & forwarding with TCP requests

[GamePlayer-8]

Good morning,

I've got a little problem with handling the TCP DNS requests with dns.message.from_wire(), which is returning dns.name.BadLabelType: The label type in DNS name wire format is unknown.. That issue doesn't occur with UDP packet handling received from udp_socket.recvfrom(1024).

My basic script looks like so:

LISTEN_HOST="0.0.0.0"
LISTEN_PORT="5353"
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind((LISTEN_HOST, int(LISTEN_PORT)))
server_socket.listen()

while True:
    conn, addr = server_socket.accept()
    data = conn.recv(1024)
    request = dns.message.from_wire(data)
    conn.sendall(request.to_wire())
    conn.close()

How to parse TCP requests with dns.message?

[rthalley]

Take a look at this source for an example of how to do it. TCP is a byte stream, so messages are encoded as a two byte length and then the message content. First you read the length then you read that many bytes to get the message.

[GamePlayer-8]

Alright, I have adapted that script to my code:

import socket
import dns.query
import dns.message

LISTEN_HOST="0.0.0.0"
LISTEN_PORT="5353"
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind((LISTEN_HOST, int(LISTEN_PORT)))
server_socket.listen()

while True:
    conn, addr = server_socket.accept()
    query = dns.query.receive_tcp(conn)
    request = query[0] # same as from dns.message.from_wire()
    
    dns.query.send_tcp(conn, request.to_wire())
    conn.close()

thank you again for help.