add Dockerfile

.gitignore

@@ -1 +1,3 @@
-venv
+venv
+*.log
+socket

Dockerfile

@@ -0,0 +1,8 @@
+FROM python:3.8
+WORKDIR /code
+COPY requirements.txt .
+RUN pip install -r requirements.txt
+COPY src/ .
+EXPOSE 53/tcp
+EXPOSE 53/udp
+CMD [ "python", "./dnproxy.py" ] 

requirements.txt

@@ -4,8 +4,15 @@ chardet==4.0.0
 cryptography==3.4.5
 dnspython==2.1.0
 idna==2.10
+lxml==4.6.2
 pycparser==2.20
 pyfiglet==0.8.post1
+pytils==0.3
+PyYAML==5.4.1
 requests==2.25.1
 requests-toolbelt==0.9.1
+selectors==0.0.14
+six==1.15.0
 urllib3==1.26.3
+user-agent==0.1.9
+weblib==0.1.30

src/dnproxy.py

@@ -0,0 +1,111 @@
+#!/usr/bin/env python3
+
+import sys
+import socket
+import selectors
+import types
+import yaml
+import logging
+from dns import message, query
+from pyfiglet import Figlet
+import binascii
+import time
+
+# General config
+f = Figlet(font='slant')
+
+# Load Config
+with open("dnproxy.yml", "r") as configfile:
+    cfg = yaml.load(configfile, Loader=yaml.FullLoader)
+
+# create logger
+logger = logging.getLogger('dnproxy')
+logger.setLevel(logging.DEBUG)
+ch = logging.StreamHandler()
+ch.setLevel(logging.INFO)
+formatter = logging.Formatter("%(asctime)s - %(name)s - [%(levelname)s] - %(message)s ") # I am printing thread id here
+ch.setFormatter(formatter)
+logger.addHandler(ch)
+
+# Init
+logger.info(f.renderText('dnproxy'))
+
+HOST = cfg['dnproxy']['host']
+PORT = cfg['dnproxy']['port']
+UPSTREAM_IP = cfg['upstream']['ip']
+TLS_HOSTNAME = cfg['upstream']['hostname']
+
+sel = selectors.DefaultSelector()
+
+def receive_message(sock):
+    (wire, host) = sock.recvfrom(1024)
+    q = message.from_wire(wire)
+    logger.info(f'UDP Socket - Query ID: {q.id}, Question:{q.question}')
+    r = query.tls(q, UPSTREAM_IP, server_hostname=TLS_HOSTNAME)
+    logger.info(f'UDP Socket - Query ID: {q.id}, Answer: {r.answer}')
+    wire = r.to_wire()
+    sock.sendto(wire, host)
+
+def accept_wrapper(sock):
+    conn, addr = sock.accept()  # Should be ready to read
+    logger.debug(f"TCP Socket - Accepted connection from {addr[0]}:{addr[1]}")
+    conn.setblocking(False)
+    data = types.SimpleNamespace(addr=addr, inb=b"", outb=b"")
+    events = selectors.EVENT_READ | selectors.EVENT_WRITE
+    sel.register(conn, events, data=data)
+
+def service_connection(key, mask):
+    sock = key.fileobj
+    data = key.data
+    if mask & selectors.EVENT_READ:
+        recv_data = sock.recv(1024)
+        if recv_data:
+            data.outb += recv_data
+        else:
+            logger.debug(f"TCP Socket - Closing connection to {data.addr[0]}:{data.addr[1]}")
+            sel.unregister(sock)
+            sock.close()
+    if mask & selectors.EVENT_WRITE:
+        if data.outb:
+            q = message.from_wire(data.outb[2:])
+            logger.info(f'TCP Socket - Question from {data.addr[0]}:{data.addr[1]}, Query ID: {q.id}, Question:{q.question}')
+            r = query.tls(q, UPSTREAM_IP, server_hostname=TLS_HOSTNAME)
+            logger.info(f'TCP Socket - Response to {data.addr[0]}:{data.addr[1]}, Query ID: {q.id}, Answer: {r.answer}')
+            wire = r.to_wire()
+            length = binascii.unhexlify("%04x" % len(wire))
+            if r:
+                sent = sock.send(length+wire)
+                data.outb = data.outb[sent:]
+
+
+if __name__=="__main__":
+
+    # Sockets Creations
+
+    tsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    tsock.bind((HOST, PORT))
+    tsock.listen()
+    logger.info(f"TCP Socket - Listening on {HOST}:{PORT}")
+    tsock.setblocking(False)
+    sel.register(tsock, selectors.EVENT_READ, data=None)
+
+    usock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    usock.bind((HOST, PORT))
+    logger.info(f"UDP Socket - Listening on {HOST}:{PORT}")
+    sel.register(usock, selectors.EVENT_READ, data=None)
+
+    try:
+        while True:
+            events = sel.select(timeout=None)
+            for key, mask in events:
+                if key.data is None:
+                    if key.fileobj.type == socket.SOCK_STREAM:
+                        accept_wrapper(key.fileobj)
+                    elif key.fileobj.type == socket.SOCK_DGRAM:
+                        receive_message(key.fileobj)
+                else:
+                    service_connection(key, mask)
+    except KeyboardInterrupt:
+        logger.info("Caught keyboard interrupt, exiting")
+    finally:
+        sel.close()

src/dnproxy.yml

@@ -0,0 +1,6 @@
+dnproxy:
+  host: "0.0.0.0"
+  port: 53
+upstream:
+  ip: "1.1.1.1"
+  hostname: "cloudflare-dns.com"