create simple resolver

Makefile

@@ -36,6 +36,7 @@ install_basic: systemd scripts bin
 	cp scripts/inner_basic.sh /snacks/wireguard/scripts/inner_basic.sh
 	cp scripts/is_root_namespace.py /snacks/wireguard/scripts/is_root_namespace.py
 	cp scripts/dns.nft /snacks/wireguard/scripts/dns.nft
+	cp scripts/create_conf.py /snacks/wireguard/scripts/create_conf.py
 	cat scripts/vpn_prompt.sh >> /etc/zsh/zshrc
 	cp bin/vpn /usr/local/bin/vpn
 	setcap cap_sys_admin,cap_sys_ptrace=ep /usr/local/bin/vpn

scripts/connect_basic.py

@@ -66,6 +66,9 @@ def wireguard():
             "vpn",
         ]
     )
+    subprocess.run(
+        ["nsenter", "--net=/proc/1/ns/net", "/snacks/wireguard/scripts/create_conf.py"],
+    )
     subprocess.run(
         ["/snacks/wireguard/scripts/inner_basic.sh"],
     )

scripts/create_conf.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+import pydantic
+from typing import Optional
+import socket
+
+
+class Config(pydantic.BaseModel):
+    public_key: str
+    host: str
+    port: int
+    private_key: str
+
+
+def write_wg(config: Config):
+    wg_conf = (
+        "[Interface]\n"
+        f"privatekey = {config.private_key}\n\n"
+        "[Peer]\n"
+        f"publickey = {config.public_key}\n"
+        f"endpoint = {config.host}:{config.port}\n"
+        "persistentkeepalive = 20\n"
+        "allowedips = 0.0.0.0/0, ::/0\n"
+    )
+
+    try:
+        with open("/run/vpnclient/wg.conf", mode="w", encoding="utf-8") as f:
+            f.write(wg_conf)
+    except IOError:
+        pass
+
+
+def get_config() -> Optional[Config]:
+    with open("/snacks/wireguard/wg.json", "r", encoding="utf-8") as f:
+        config = Config.parse_raw(f.read())
+        config.host = socket.gethostbyname(config.host)
+        return config
+
+
+write_wg(get_config())

systemd/vpnclient-wg-basic.service

@@ -12,6 +12,8 @@ EnvironmentFile=/snacks/wireguard/env
 ExecStart=/snacks/wireguard/scripts/connect_basic.py
 NetworkNamespacePath=/run/vpn/net
 RemainAfterExit=true
+RuntimeDirectory=vpnclient
+RuntimeDirectoryMode=0600
 
 [Install]
 WantedBy=multi-user.target