Files
ddns-service/src/ddns_daemon/server.py
2026-01-18 06:16:15 +01:00

448 lines
14 KiB
Python

"""HTTP(S) server for DDNS updates."""
from __future__ import annotations
import base64
import ipaddress
import json
import logging
import signal
import ssl
from datetime import datetime
from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
from urllib.parse import parse_qs, urlparse
import argon2
from .cleanup import ExpiredRecordsCleanupThread, RateLimitCleanupThread
from .dns import detect_ip_type
from .logging import clear_txn_id, set_txn_id
from .models import DoesNotExist, get_hostname_for_user, get_user
from .validation import encode_hostname, ValidationError
def extract_param(params, aliases):
"""Extract first matching param from query params."""
for alias in aliases:
val = params.get(alias, [None])[0]
if val is not None:
return val
return None
class ProxyHeaderError(Exception):
"""Raised when expected proxy header is missing."""
pass
def _parse_trusted_proxies(proxies):
"""Parse list of IPs/networks into ip_network objects."""
networks = []
for proxy in proxies:
try:
if "/" not in proxy:
addr = ipaddress.ip_address(proxy)
if addr.version == 4:
proxy = proxy + "/32"
else:
proxy = proxy + "/128"
networks.append(ipaddress.ip_network(proxy, strict=False))
except ValueError:
logging.warning(f"Invalid trusted proxy: {proxy}")
return networks
def _is_trusted_proxy(client_ip, trusted_networks):
"""Check if client IP is in trusted proxy networks."""
try:
addr = ipaddress.ip_address(client_ip)
for network in trusted_networks:
if addr in network:
return True
except ValueError:
pass
return False
class DDNSServer(ThreadingHTTPServer):
"""HTTP server with Application instance."""
def __init__(self, app, address):
"""
Initialize server with application.
Args:
app: Application instance.
address: (host, port) tuple.
"""
self.app = app
self.proxy_header = app.config["daemon"].get("proxy_header", "")
self.trusted_networks = _parse_trusted_proxies(
app.config["daemon"].get("trusted_proxies", [])
)
super().__init__(address, DDNSRequestHandler)
class DDNSRequestHandler(BaseHTTPRequestHandler):
"""HTTP request handler for DDNS updates."""
@property
def app(self):
"""Get application instance from server."""
return self.server.app
def log_message(self, format_str, *args):
"""Override to use our logger."""
msg = f"{self.address_string()} - {format_str % args}"
if self.app.config["daemon"]["log_requests"]:
logging.info(msg)
else:
logging.debug(msg)
def send_response_body(self, code, body, content_type="text/plain"):
"""Send response with body."""
self.send_response(code)
self.send_header("Content-Type", content_type)
self.send_header("Content-Length", str(len(body)))
self.end_headers()
self.wfile.write(body.encode())
def wants_json(self):
"""Check if client wants JSON response."""
accept = self.headers.get("Accept", "")
return "application/json" in accept
def respond(self, code, status, **kwargs):
"""Send response in appropriate format."""
if self.wants_json():
data = {"status": status, **kwargs}
self.send_response_body(code, json.dumps(data), "application/json")
else:
# DynDNS-compatible plain text
parts = [status]
if "ipv4" in kwargs and kwargs["ipv4"]:
parts.append(kwargs["ipv4"])
if "ipv6" in kwargs and kwargs["ipv6"]:
parts.append(kwargs["ipv6"])
self.send_response_body(code, " ".join(parts))
def get_client_ip(self):
"""Get client IP, considering configured proxy header if trusted."""
direct_ip = self.client_address[0]
proxy_header = self.server.proxy_header
if not proxy_header:
return direct_ip
if not _is_trusted_proxy(direct_ip, self.server.trusted_networks):
return direct_ip
forwarded = self.headers.get(proxy_header)
if not forwarded:
raise ProxyHeaderError(
f"Missing {proxy_header} header from trusted proxy"
)
return forwarded.split(",")[0].strip()
def parse_basic_auth(self):
"""Parse Basic Auth header."""
auth = self.headers.get("Authorization", "")
if not auth.startswith("Basic "):
return None, None
try:
decoded = base64.b64decode(auth[6:]).decode("utf-8")
if ":" in decoded:
username, password = decoded.split(":", 1)
return username, password
except Exception:
pass
return None, None
def do_GET(self):
"""Handle GET requests."""
set_txn_id()
try:
self._handle_get_request()
finally:
clear_txn_id()
def _handle_get_request(self):
"""Handle GET request logic."""
try:
client_ip = self.get_client_ip()
except ProxyHeaderError as e:
logging.error(f"Proxy header error: {e}")
self.send_response_body(400, "Bad Request")
return
# Bad rate limit check
if self.app.rate_limiter:
blocked, retry = self.app.rate_limiter.is_blocked_bad(client_ip)
if blocked:
logging.warning(
f"Rate limited (bad requests): client={client_ip}, "
f"retry_after={retry}")
self.respond(429, "abuse")
return
# Parse URL
parsed = urlparse(self.path)
# Find matching endpoint
endpoint = self.app.config["_endpoint_map"].get(parsed.path)
if endpoint is None:
self.send_response_body(404, "Not Found")
return
# Parse query parameters
params = parse_qs(parsed.query)
# Get credentials
username, password = self.parse_basic_auth()
if username is None:
username = extract_param(params, endpoint["params"]["username"])
password = extract_param(params, endpoint["params"]["password"])
if not username or not password:
logging.warning(f"Auth failed: client={client_ip} user=anonymous")
self._handle_bad_request(client_ip, 401, "badauth")
return
# Validate credentials
try:
user = get_user(username)
self.app.password_hasher.verify(user.password_hash, password)
except (DoesNotExist, argon2.exceptions.VerifyMismatchError):
logging.warning(f"Auth failed: client={client_ip} user={username}")
self._handle_bad_request(client_ip, 401, "badauth")
return
# Get hostname parameter
hostname_param = extract_param(params, endpoint["params"]["hostname"])
if not hostname_param:
logging.warning(f"Missing hostname: client={client_ip} user={username}")
self._handle_bad_request(client_ip, 400, "nohost")
return
# Validate and encode hostname
try:
hostname_param = encode_hostname(hostname_param)
except ValidationError:
logging.warning(
f"Invalid hostname: client={client_ip}, "
f"hostname={hostname_param}")
self._handle_bad_request(client_ip, 400, "nohost")
return
# Check hostname ownership
try:
hostname = get_hostname_for_user(hostname_param, user)
except DoesNotExist:
logging.warning(
f"Access denied: client={client_ip} user={username} "
f"hostname={hostname_param}"
)
self._handle_bad_request(client_ip, 403, "nohost")
return
# Good rate limit check
if self.app.rate_limiter:
blocked, retry = self.app.rate_limiter.is_blocked_good(client_ip)
if blocked:
logging.warning(f"Rate limited: client={client_ip}, retry_after={retry}")
self.respond(429, "abuse", retry_after=retry)
return
# Record good request
if self.app.rate_limiter:
self.app.rate_limiter.record_good(client_ip)
# Determine IPs to update
result = self._process_ip_update(hostname, params, endpoint, client_ip)
if result:
code, status, *kwargs = result
if kwargs:
self.respond(code, status, **kwargs[0])
else:
self.respond(code, status)
def _handle_bad_request(self, client_ip, code, status):
"""Handle bad request and record in rate limiter."""
if self.app.rate_limiter:
self.app.rate_limiter.record_bad(client_ip)
self.respond(code, status)
def _process_ip_update(self, hostname, params, endpoint, client_ip):
"""Process IP update for hostname."""
myip = extract_param(params, endpoint["params"]["ipv4"])
myip6 = extract_param(params, endpoint["params"]["ipv6"])
ipv4 = None
ipv6 = None
# Process myip parameter
if myip:
try:
rtype, myip = detect_ip_type(myip)
if rtype == "A":
ipv4 = myip
else:
ipv6 = myip
except ValueError:
return (400, "badip")
# Process myip6 parameter
if myip6:
try:
rtype, myip6 = detect_ip_type(myip6)
if rtype == "AAAA":
ipv6 = myip6
else:
return (400, "badip")
except ValueError:
return (400, "badip")
# Auto-detect from client IP if no params
if ipv4 is None and ipv6 is None:
try:
rtype, ip = detect_ip_type(client_ip)
if rtype == "A":
ipv4 = ip
else:
ipv6 = ip
except ValueError:
return (400, "badip")
now = datetime.now()
changed = False
if ipv4:
hostname.last_ipv4_update = now
if ipv4 != hostname.last_ipv4:
# Update DNS IPv4 record
try:
self.app.dns_service.update_record(
hostname.hostname,
hostname.zone,
ipv4,
hostname.dns_ttl
)
hostname.last_ipv4 = ipv4
changed = True
except Exception as e:
hostname.save()
logging.error(
f"DNS update failed: client={client_ip} hostname={hostname.hostname} "
f"zone={hostname.zone} ipv4={ipv4} error={e}"
)
return (500, "dnserr")
if ipv6:
hostname.last_ipv6_update = now
if ipv6 != hostname.last_ipv6:
# Update DNS IPv6 record
try:
self.app.dns_service.update_record(
hostname.hostname,
hostname.zone,
ipv6,
hostname.dns_ttl
)
hostname.last_ipv6 = ipv6
changed = True
except Exception as e:
hostname.save()
logging.error(
f"DNS update failed: client={client_ip} hostname={hostname.hostname} "
f"zone={hostname.zone} ipv6={ipv6} error={e}"
)
return (500, "dnserr")
# Update database
hostname.save()
changed_addrs = ""
if ipv4:
changed_addrs += f"ipv4={ipv4}"
if ipv6:
changed_addrs += f" ipv6={ipv6}"
if not changed:
logging.info(
f"No change: client={client_ip} hostname={hostname.hostname} "
f"zone={hostname.zone} {changed_addrs}"
)
return (
200, "nochg",
{"ipv4": hostname.last_ipv4, "ipv6": hostname.last_ipv6}
)
logging.info(
f"Updated: client={client_ip} hostname={hostname.hostname} "
f"zone={hostname.zone} {changed_addrs}"
)
return (
200, "good",
{"ipv4": hostname.last_ipv4, "ipv6": hostname.last_ipv6}
)
def run_daemon(app):
"""
Run the DDNS daemon.
Args:
app: Application instance with initialized services.
"""
config = app.config
# Setup server
host = config["daemon"]["host"]
port = config["daemon"]["port"]
server = DDNSServer(app, (host, port))
# Setup TLS if enabled
if config["daemon"]["ssl"]:
context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
context.load_cert_chain(
config["daemon"]["ssl_cert_file"],
config["daemon"]["ssl_key_file"]
)
server.socket = context.wrap_socket(server.socket, server_side=True)
proto = "https"
else:
proto = "http"
# Start cleanup threads
expired_cleanup_thread = ExpiredRecordsCleanupThread(app)
expired_cleanup_thread.start()
ratelimit_cleanup_thread = RateLimitCleanupThread(app)
ratelimit_cleanup_thread.start()
# Setup signal handlers
def signal_handler(signum, frame):
logging.info(f"Signal received: {signum}, shutting down")
app.signal_shutdown()
signal.signal(signal.SIGTERM, signal_handler)
signal.signal(signal.SIGINT, signal_handler)
paths = ", ".join(ep["path"] for ep in config["endpoints"])
logging.info(f"Daemon started: {proto}://{host}:{port} endpoints=[{paths}]")
# Run server
server.timeout = 1.0
while not app.is_shutting_down():
server.handle_request()
# Cleanup
expired_cleanup_thread.stop()
ratelimit_cleanup_thread.stop()
expired_cleanup_thread.join(timeout=5)
ratelimit_cleanup_thread.join(timeout=5)
server.server_close()
logging.info("Daemon stopped")