Files
linux-cloud-router/debian-package/src/usr/lib/vpn-router/generate-config
T

90 lines
3.4 KiB
Python
Executable File

#!/usr/bin/python3
"""Write a candidate vpn-router.json to the path given on the command line.
Called from postinst, which hands the result to ucf(1). ucf compares it with
/etc/vpn-router/vpn-router.json and decides what to do about local changes, so
this script never writes to /etc and never has to worry about destroying an
administrator's edits.
The candidate is built in three layers, each overriding the one before:
1. the shipped defaults
2. the current contents of /etc/vpn-router/vpn-router.json, if it exists
3. any debconf answer that was actually given
Layer 2 is what makes reconfiguration safe: a setting the administrator edited
by hand, and that debconf has nothing to say about, is carried through
unchanged, so ucf only sees a diff where something really changed. An empty
answer means "leave alone", which is why clearing the pre-shared key from the
debconf database after installation does not blank it on the next
dpkg-reconfigure.
Answers arrive as VPN_ROUTER_* environment variables and are converted to the
type of the setting they fill: comma-separated lists become arrays, "true" and
"false" become booleans and digits become integers.
"""
import json
import os
import sys
sys.path.insert(0, os.path.dirname(os.path.realpath(__file__)))
import vpnrouter
# environment variable -> (section, option)
ANSWERS = {
'VPN_ROUTER_PLATFORM': ('general', 'platform'),
'VPN_ROUTER_MODE': ('general', 'mode'),
'VPN_ROUTER_INT_ADDR': ('local', 'int_addr'),
'VPN_ROUTER_EXTERNAL_INTERFACE': ('interfaces', 'external'),
'VPN_ROUTER_INTERNAL_INTERFACE': ('interfaces', 'internal'),
'VPN_ROUTER_LOCAL_FQDN': ('wan', 'local_fqdn'),
'VPN_ROUTER_LOCAL_ID_MODE': ('wan', 'local_id_mode'),
'VPN_ROUTER_LOCAL_CIDRS': ('local', 'cidrs'),
'VPN_ROUTER_INT_GATEWAY_IP': ('local', 'int_gateway_ip'),
'VPN_ROUTER_REMOTE_ADDRS': ('remote', 'addrs'),
'VPN_ROUTER_REMOTE_ID': ('remote', 'id'),
'VPN_ROUTER_REMOTE_CIDRS': ('remote', 'cidrs'),
'VPN_ROUTER_PSK': ('remote', 'psk'),
'VPN_ROUTER_P2S_ENABLED': ('p2s', 'enabled'),
'VPN_ROUTER_P2S_ADDRESS_POOL': ('p2s', 'address_pool'),
'VPN_ROUTER_P2S_CA_NAME': ('p2s', 'ca_name'),
'VPN_ROUTER_WG_ENABLED': ('wireguard', 'enabled'),
'VPN_ROUTER_WG_ADDRESS': ('wireguard', 'address'),
'VPN_ROUTER_WG_LISTEN_PORT': ('wireguard', 'listen_port'),
}
def main():
if len(sys.argv) != 2:
print('usage: generate-config OUTPUT', file=sys.stderr)
return 2
output = sys.argv[1]
cfg = vpnrouter.load_config()
for variable, (section, option) in ANSWERS.items():
value = os.environ.get(variable)
if not value:
continue
# A value that does not convert is kept as a string for validate() to report.
default = vpnrouter.SCHEMA[section][option]
if isinstance(default, bool):
value = value == 'true'
elif isinstance(default, int):
value = int(value) if value.isdigit() else value
elif isinstance(default, list):
value = [item.strip() for item in value.split(',') if item.strip()]
cfg[section][option] = value
with open(output, 'w', encoding='utf-8') as handle:
json.dump(cfg, handle, indent=2)
handle.write('\n')
os.chmod(output, 0o600)
return 0
if __name__ == '__main__':
sys.exit(main())