sane-vpn: fix to provide bunpen with the gateway address for "sane-vpn do none ..."

pkgs/by-name/sane-scripts/src/sane-vpn

@@ -175,6 +175,26 @@ def get_dns_resolvers_for_dev(dev: str) -> list[str]:
 
     return nameservers
 
+def get_addr_v4_for_dev(dev: str) -> str | None:
+    # output looks like IP4.ADDRESS[1]:192.168.1.72
+    nmcli_stdout = subprocess.check_output([
+        "nmcli", "-t", "-f", "IP4.ADDRESS", "device", "show", dev
+    ]).decode("utf-8")
+    addrs = []
+    for line in nmcli_stdout.splitlines():
+        line = line.strip()
+        if not line:
+            continue
+        _fname, addr = line.split(":")
+        if not addr:
+            continue
+        if "/" in addr:
+            addr, _subnet = addr.split("/")
+        if not addr:
+            continue
+        addrs.append(addr)
+
+    return addrs[0] if len(addrs) else None
 
 def get_connected_networks() -> list[str]:
     # output looks like:
@@ -215,8 +235,9 @@ def get_vpn(vpn_name: str) -> VpnConfig:
         return load_vpns()[vpn_name]
     elif vpn_name == "none":
         dev = get_default_dev()
+        addr_v4 = get_addr_v4_for_dev(dev)
         dns = get_dns_resolvers_for_dev(dev)
-        return VpnConfig(dev=dev or "all", dns=dns)
+        return VpnConfig(dev=dev or "all", addr_v4=addr_v4, dns=dns)
     elif vpn_name == "unmetered":
         for dev in get_connected_networks():
             dns = get_dns_resolvers_for_dev(dev)