Sovran_Systems/Sovran_SystemsOS
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases 6 Wiki Activity

feat(public-ip): unify public-IP detection into one privacy-first script

Browse Source 
The public IP was previously detected independently in three places,
each contacting a different third party: the Hub (HTTPS echo via
api.ipify.org / ifconfig.me / icanhazip.com on every API call and
background tick), DDNS (myip.opendns.com via OpenDNS), and LiveKit
(embedded STUN). Consolidate into a single detector with one shared
cache so every consumer reads the same value with minimal exposure.

- add modules/core/public-ip.nix: installs /var/lib/sovran/public-ip.py
  (pure Python stdlib, no new deps) writing /var/lib/secrets/external-ip
- detection chain (first success wins): explicit pin, fresh cache
  (default TTL 300s), STUN binding request over UDP (one packet, no
  metadata), DNS myip.opendns.com query, then OPT-IN HTTPS echo
  (publicIP.httpsEcho, empty by default — never contacted unless listed)
- privacy: while the cache is fresh zero third parties are contacted;
  at most one party learns the IP per refresh interval, via the least
  exposing mechanism available
- hub (server.py): _get_external_ip() now reads the shared detector /
  cache instead of calling ipify/ifconfig/icanhazip directly
- ddns (njalla.nix): use the shared detector instead of a separate
  OpenDNS dig; allow the hardened service to write /var/lib/secrets
- element-calling: livekit-turn-setup falls back to the shared
  detector on cold boot; add LiveKit webhooks to lk-jwt-service
  (sfu_webhook) so abrupt disconnects are cleaned up immediately;
  set LIVEKIT_SANITY_CHECK_INTERVAL_SECONDS=60 as a missed-webhook
  guard; drop the dead services.livekit.settings block and set
  openFirewall=false (Caddy fronts the SFU; no public 7880/tcp)
- new options: sovran_systemsOS.publicIP.{stunServer,stunPort,
  dnsResolver,httpsEcho,cacheTTL}
This commit is contained in:
naturallaw777
2026-08-20 16:40:00 -05:00
parent 224ea99ce4
commit ac6c498615
5 changed files with 401 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files
modules/core/public-ip.nix
+319
View File
@@ -0,0 +1,319 @@
# ── Unified public-IP detection (privacy-first) ─────────────────────────────
#
# One script, one cache file, every consumer on the system reads the same
# value. Previously the public IP was detected independently in three places,
# each phoning home to a different third party:
# * the Hub (server.py _get_external_ip) → api.ipify.org / ifconfig.me /
# icanhazip.com over HTTPS on every /api/network call and every
# background-loop tick
# * DDNS (ddns-update.py) → myip.opendns.com via OpenDNS
# * LiveKit → STUN (its own embedded detection)
#
# This module replaces all of that with a single script
# (/var/lib/sovran/public-ip.py) that detects the IP once per TTL using the
# least-exposing mechanism available, and caches it in
# /var/lib/secrets/external-ip. Consumers (Hub, DDNS, LiveKit) read the cache
# and only invoke the script when it is missing or stale.
#
# Detection chain (first success wins, stops immediately):
# 1. pin — sovran_systemsOS.elementCalling.externalIP (baked in)
# 2. cache — /var/lib/secrets/external-ip if newer than cacheTTL
# 3. STUN — UDP binding request (one packet, no application data,
# no HTTP metadata; the same protocol every WebRTC client
# uses). Server configurable via publicIP.stunServer.
# 4. DNS — "myip.opendns.com" A query via publicIP.dnsResolver
# (single DNS query, no HTTP headers)
# 5. HTTPS echo — ONLY endpoints listed in publicIP.httpsEcho (empty by
# default → never contacted)
#
# Privacy property: while the cache is fresh, zero third parties are
# contacted. When detection runs, at most ONE party learns the IP per
# refresh interval (default 5 minutes), and the STUN/DNS mechanisms expose
# nothing beyond the bare address.
{
config,
pkgs,
lib,
...
}:
let
stunServer = config.sovran_systemsOS.publicIP.stunServer;
stunPort = config.sovran_systemsOS.publicIP.stunPort;
dnsResolver = config.sovran_systemsOS.publicIP.dnsResolver;
httpsEcho = config.sovran_systemsOS.publicIP.httpsEcho;
cacheTTL = config.sovran_systemsOS.publicIP.cacheTTL;
# Optional pin shared with element-calling (baked in at build time).
pin = if config.sovran_systemsOS.elementCalling.externalIP != null then config.sovran_systemsOS.elementCalling.externalIP else "";
echoList = lib.concatStringsSep "," (map (u: "'${u}'") httpsEcho);
in
{
options.sovran_systemsOS.publicIP = {
stunServer = lib.mkOption {
type = lib.types.str;
default = "stun.l.google.com";
description = ''
STUN server used to discover the public IP over UDP. STUN is the most
privacy-preserving detection mechanism: a single stateless packet,
no HTTP metadata. Only used when the cache is stale.
'';
};
stunPort = lib.mkOption {
type = lib.types.port;
default = 19302;
};
dnsResolver = lib.mkOption {
type = lib.types.str;
default = "resolver4.opendns.com";
description = ''
DNS resolver used as fallback (myip.opendns.com trick) when STUN is
unavailable (e.g. ISP blocks UDP egress). A single DNS query, no
HTTP headers.
'';
};
httpsEcho = lib.mkOption {
type = lib.types.listOf lib.types.str;
default = [ ];
example = [ "https://api.ipify.org" ];
description = ''
OPT-IN HTTPS endpoints that return the caller's public IP as a bare
IPv4 literal. Each listed endpoint observes this server's public IP
and HTTP metadata every time detection runs. Empty by default — no
HTTPS echo service is ever contacted unless you add one here. This is
the last-resort fallback after STUN and DNS.
'';
};
cacheTTL = lib.mkOption {
type = lib.types.int;
default = 300;
description = "Seconds the detected public IP is cached before re-detection.";
};
};
# ── Install the unified detector ──────────────────────────────────────────
system.activationScripts.sovranPublicIpInstall = lib.stringAfter [ "users" ] ''
install -d -m 0755 /var/lib/sovran
cat > /var/lib/sovran/public-ip.py <<'PYEOF'
#!/usr/bin/env python3
"""sovran-public-ip — one detector, one cache, every consumer reads the same IP.
Privacy-first detection chain (first success wins):
1. pin — baked in from sovran_systemsOS.elementCalling.externalIP
2. cache — /var/lib/secrets/external-ip if newer than CACHE_TTL seconds
3. STUN — UDP binding request (one packet, no application data)
4. DNS — myip.opendns.com A query via the configured resolver
5. HTTPS — ONLY endpoints baked in from publicIP.httpsEcho (opt-in)
Usage:
public-ip.py check print current public IP (cache first; refresh if stale)
public-ip.py refresh force re-detection, update the cache file, print IP
Exit status: 0 with the IP on stdout on success; 1 if no IP is available
(cached value, if any, is still printed to stdout with a warning on stderr).
"""
import ipaddress
import os
import random
import socket
import struct
import sys
import time
import urllib.request
CACHE_FILE = "/var/lib/secrets/external-ip"
PIN = "${pin}"
STUN_SERVER = "${stunServer}"
STUN_PORT = ${toString stunPort}
DNS_RESOLVER = "${dnsResolver}"
DNS_HOST = "myip.opendns.com"
ECHO_URLS = [ ${echoList} ]
CACHE_TTL = ${toString cacheTTL}
TIMEOUT = 3.0
# ---------------------------------------------------------------------------
# Detection primitives
# ---------------------------------------------------------------------------
def is_usable_ip(text: str) -> bool:
"""True if text is a globally routable IPv4 that LiveKit may advertise."""
try:
ip = ipaddress.ip_address(text)
except ValueError:
return False
if ip.version != 4:
return False
if (ip.is_private or ip.is_loopback or ip.is_link_local or ip.is_multicast
or ip.is_reserved or ip.is_unspecified or not ip.is_global):
return False
# RFC 6598 shared (CGNAT) space — not reachable from the internet.
if ip in ipaddress.ip_network("100.64.0.0/10"):
return False
return True
def stun_public_ip() -> str | None:
"""RFC 5389 Binding request over UDP; returns the mapped (public) IPv4."""
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.settimeout(TIMEOUT)
try:
txid = random.randbytes(12)
req = struct.pack("!HHI", 0x0001, 0, 0) + txid # Binding request
sock.sendto(req, (STUN_SERVER, STUN_PORT))
data, _ = sock.recvfrom(2048)
except OSError:
return None
finally:
sock.close()
if len(data) < 20:
return None
mtype, _mlen = struct.unpack("!HH", data[:4])
if mtype != 0x0101: # Binding success response
return None
cookie = data[4:8]
i = 20
while i + 4 <= len(data):
atype, alen = struct.unpack("!HH", data[i : i + 4])
aval = data[i + 4 : i + 4 + alen]
if atype in (0x0001, 0x0020) and len(aval) >= 8: # MAPPED / XOR-MAPPED
family = aval[1]
if family == 0x01: # IPv4
raw = aval[4:8]
if atype == 0x0020: # XOR with magic cookie + txid prefix
raw = bytes(b ^ c for b, c in zip(raw, cookie + txid[:4]))
return socket.inet_ntop(socket.AF_INET, raw)
i += 4 + ((alen + 3) // 4) * 4
return None
def dns_public_ip() -> str | None:
"""Minimal DNS A query for myip.opendns.com against the given resolver."""
qid = random.randint(0, 0xFFFF)
qname = b"".join(bytes([len(p)]) + p.encode() for p in DNS_HOST.split(".")) + b"\x00"
query = struct.pack("!HHHHHH", qid, 0x0100, 1, 0, 0, 0) + qname + struct.pack("!HH", 1, 1)
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.settimeout(TIMEOUT)
try:
sock.sendto(query, (DNS_RESOLVER, 53))
data, _ = sock.recvfrom(4096)
except OSError:
return None
finally:
sock.close()
try:
if len(data) < 12:
return None
rid, _flags, _qd, an, _ns, _ar = struct.unpack("!HHHHHH", data[:12])
if rid != qid or an == 0:
return None
i = 12
for _ in range(_qd): # skip question
while data[i] != 0:
i += 1 + data[i]
i += 5
for _ in range(an):
if data[i] & 0xC0 == 0xC0:
i += 2
else:
while data[i] != 0:
i += 1 + data[i]
i += 1
rtype, _rclass, _ttl, rdlen = struct.unpack("!HHIH", data[i : i + 10])
i += 10
if rtype == 1 and rdlen == 4:
return socket.inet_ntop(socket.AF_INET, data[i : i + 4])
i += rdlen
except (IndexError, struct.error):
return None
return None
def echo_public_ip() -> str | None:
"""Opt-in HTTPS echo endpoints (baked in at build time; empty by default)."""
for url in ECHO_URLS:
try:
req = urllib.request.Request(url, headers={"User-Agent": "sovran-public-ip"})
with urllib.request.urlopen(req, timeout=TIMEOUT) as resp:
text = resp.read().decode().strip()
if is_usable_ip(text):
return text
except Exception:
continue
return None
# ---------------------------------------------------------------------------
# Cache handling
# ---------------------------------------------------------------------------
def read_cache() -> str:
try:
with open(CACHE_FILE) as f:
return f.read().strip()
except OSError:
return ""
def write_cache(ip: str) -> None:
try:
os.makedirs(os.path.dirname(CACHE_FILE), exist_ok=True)
tmp = f"{CACHE_FILE}.tmp"
with open(tmp, "w") as f:
f.write(ip + "\n")
os.replace(tmp, CACHE_FILE)
except OSError:
pass
def cache_fresh() -> bool:
try:
return time.time() - os.path.getmtime(CACHE_FILE) < CACHE_TTL
except OSError:
return False
def detect() -> str:
"""Run the chain; returns usable IP or an empty string."""
if PIN and is_usable_ip(PIN):
return PIN
for fn in (stun_public_ip, dns_public_ip, echo_public_ip):
try:
cand = fn()
except Exception:
continue
if cand and is_usable_ip(cand):
return cand
return ""
def main() -> int:
force = len(sys.argv) > 1 and sys.argv[1] == "refresh"
ip = ""
if not force and cache_fresh():
ip = read_cache()
if not ip:
ip = detect()
if ip:
write_cache(ip)
else:
stale = read_cache()
if stale:
print(stale)
print("WARNING: detection failed; using last known public IP", file=sys.stderr)
return 0
print("ERROR: could not determine a public IP (STUN/DNS unreachable)", file=sys.stderr)
return 1
print(ip)
return 0
if __name__ == "__main__":
sys.exit(main())
PYEOF
chmod 0555 /var/lib/sovran/public-ip.py
'';
}