Make Wi-Fi semi-declarative

flake.lock

@@ -155,6 +155,22 @@
         "type": "indirect"
       }
     },
+    "displaylinknixpkgs": {
+      "locked": {
+        "lastModified": 1717533296,
+        "narHash": "sha256-TOxOpOYy/tQB+eYQOTPQXNeUmkMghLVDBO0Gc2nj/vs=",
+        "owner": "GeoffreyFrogeye",
+        "repo": "nixpkgs",
+        "rev": "99006b6f4cd24796b1ff6b6981b8f44c9cebd301",
+        "type": "github"
+      },
+      "original": {
+        "owner": "GeoffreyFrogeye",
+        "ref": "displaylink-600",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "flake-compat": {
       "locked": {
         "lastModified": 1696426674,
@@ -649,6 +665,7 @@
     "root": {
       "inputs": {
         "disko": "disko",
+        "displaylinknixpkgs": "displaylinknixpkgs",
         "flake-utils": "flake-utils",
         "home-manager": "home-manager",
         "nix-on-droid": "nix-on-droid",

flake.nix

@@ -95,7 +95,7 @@
               repl = {
                 type = "app";
                 program = "${pkgs.writeShellScript "vivarium-repl" ''
-              ${pkgs.nix}/bin/nix repl --expr 'let flake = builtins.getFlake "${self}"; in flake // flake.nixosConfigurations // rec { pkgs = import ${nixpkgs} {}; lib = pkgs.lib; }'
+                  ${pkgs.lix}/bin/nix repl --expr 'let flake = builtins.getFlake "${self}"; in flake // flake.nixosConfigurations // rec { pkgs = import ${nixpkgs} {}; lib = pkgs.lib; }'
                 ''}";
               };
             };

os/wireless/apply.py

@@ -0,0 +1,56 @@
+"""
+"""
+
+import json
+import os
+import re
+import subprocess
+
+NETWORKS_FILE = "/etc/keys/wireless_networks.json"
+
+
+def wpa_cli(command: list[str]) -> list[bytes]:
+    command.insert(0, "wpa_cli")
+    process = subprocess.run(command, stdout=subprocess.PIPE)
+    process.check_returncode()
+    lines = process.stdout.splitlines()
+    while lines[0].startswith(b"Selected interface"):
+        lines.pop(0)
+    return lines
+
+
+network_numbers: dict[str, int] = dict()
+networks_tsv = wpa_cli(["list_networks"])
+networks_tsv.pop(0)
+for network_line in networks_tsv:
+    split = network_line.split(b"\t")
+    number = int(split[0])
+    ssid_bytes = split[1]
+    ssid = re.sub(
+        rb"\\x([0-9a-f]{2})",
+        lambda d: int(d[1], base=16).to_bytes(),
+        ssid_bytes,
+    ).decode()
+    network_numbers[ssid] = number
+
+if os.path.isfile(NETWORKS_FILE):
+    with open(NETWORKS_FILE) as fd:
+        networks = json.load(fd)
+
+    for network in networks:
+        ssid = network["ssid"]
+        if ssid in network_numbers:
+            number = network_numbers[ssid]
+        else:
+            number = int(wpa_cli(["add_network"])[0])
+        number_str = str(number)
+        for key, value in network.items():
+            if isinstance(value, str):
+                value_str = f'"{value}"'
+            elif isinstance(value, list):
+                value_str = " ".join(value)
+            else:
+                value_str = str(value)
+            ret = wpa_cli(["set_network", number_str, key, value_str])
+            if ret[0] != b"OK":
+                raise RuntimeError(f"Couldn't set {key} for {ssid}, got {ret}")

os/wireless/default.nix

@@ -1,34 +1,49 @@
 { pkgs, lib, config, ... }:
+let
+  importScript = pkgs.writers.writePython3 "install-wifi-import"
+    {
+      libraries = [ pkgs.python3Packages.pyaml ];
+    }
+    (builtins.readFile ./import.py);
+  applyScript = pkgs.writers.writePython3 "install-wifi-apply" { } (builtins.readFile ./apply.py);
+in
 {
   environment.systemPackages = [
     (pkgs.writeShellApplication {
       name = "install-wifi";
+      runtimeInputs = with pkgs; [ wpa_supplicant diffutils ];
       text = ''
         temp="$(mktemp --directory --suffix="-install-wifi")"
         cd "$temp"
-        ${
+
-          pkgs.writers.writePython3 "install-wifi-import" {
+        # Save config for diffing later
-            libraries = [ pkgs.python3Packages.pyaml ];
+        wpa_cli save_config > /dev/null
-          } (builtins.readFile ./import.py)
+        cat <(sudo cat /run/wpa_supplicant/wpa_supplicant.conf) > old.conf
-        }
+
-        sudo chown root:root wireless_networks.{env,json}
+        # Export Wi-Fi config from pass
-        sudo chmod "u=r" wireless_networks.env
+        ${importScript}
-        sudo chmod "u=r,g=r,o=r" wireless_networks.json
+
+        # Save on persistent storage for boot
+        sudo chown root:root wireless_networks.json
+        sudo chmod "u=r" wireless_networks.json
         sudo mkdir -p /etc/keys
-        sudo mv -f wireless_networks.{env,json} /etc/keys
+        sudo mv -f wireless_networks.json /etc/keys
-        cd -
+
+        # Apply configuration
+        sudo ${applyScript}
+
+        # Diff the config
+        wpa_cli save_config > /dev/null
+        cat <(sudo cat /run/wpa_supplicant/wpa_supplicant.conf) > new.conf
+        diff --color=auto -U 5 old.conf new.conf
+
+        rm old.conf new.conf
+        cd /
         rmdir "$temp"
-        rb
       '';
-      # This relies on multiple off-repo things:
+      # This relies on pass password store with wifi/${name} entries,
-      # - pass password store with wifi/${name} entries, containing wpa_supplicant networks
+      # containing wpa_supplicant networks loosely converted to YAML
-      #   loosely converted to YAML (see import.py script)
+      # (see import.py script)
-      # - In a (private) flake:
-      #   inputs.wirelessNetworks.url = "path:/etc/keys/wireless_networks.json";
-      #   inputs.wirelessNetworks.flake = false;
-      # - In NixOS config (using flake inputs):
-      #   networking.wireless.environmentFile = "/etc/keys/wireless_networks.env";
-      #   networking.wireless.networks = builtins.fromJSON (builtins.readFile wirelessNetworks);
     })
   ];
   # wireless support via wpa_supplicant
@@ -51,4 +66,10 @@
     userControlled.enable = true; # Allow some control with wpa_cli
   };
   services.chrony.serverOption = "offline";
+  systemd.services.wifi_apply = {
+    after = [ "wpa_supplicant.service" ];
+    requiredBy = [ "wpa_supplicant.service" ];
+    path = with pkgs; [ wpa_supplicant ];
+    script = "${applyScript}";
+  };
 }

os/wireless/import.py

@@ -9,7 +9,6 @@ into a format readable by Nix.
 #     sha256 = "sha256:1la36n2f31j9s03v847ig6ny9lr875q3g7smnq33dcsmf2i5gd92";
 # }
 
-import hashlib
 import json
 import os
 import subprocess
@@ -20,46 +19,6 @@ import yaml
 
 PASSWORD_STORE = os.environ["PASSWORD_STORE_DIR"]
 SUBFOLDER = "wifi"
-SEPARATE_PASSWORDS = True
-
-
-class Password:
-    all: list["Password"] = list()
-
-    def __init__(self, path: str, content: str):
-        self.path = path
-        self.content = content
-
-        Password.all.append(self)
-
-    def var(self) -> str:
-        # return self.path.split("/")[-1].upper()
-        m = hashlib.sha256()
-        m.update(self.path.encode())
-        return "p" + m.hexdigest().upper()
-
-    def val(self) -> str:
-        return self.content
-
-    def exists(self) -> bool:
-        return not not self.content
-
-    def key(self) -> str:
-        if SEPARATE_PASSWORDS:
-            return f"@{self.var()}@"
-        else:
-            return self.val()
-
-    @classmethod
-    def vars(cls) -> dict[str, str]:
-        vars = dict()
-        for password in cls.all:
-            if not password.content:
-                continue
-            var = password.var()
-            assert var not in vars, f"Duplicate key: {var}"
-            vars[var] = password.val()
-        return vars
 
 
 def list_networks() -> list[str]:
@@ -75,28 +34,11 @@ def list_networks() -> list[str]:
         file = filename[:-4]
         path = os.path.join(SUBFOLDER, file)
         paths.append(path)
+    paths.sort()
     return paths
 
 
-def format_wpa_supplicant_conf(conf: dict, indent: str = "") -> str:
+networks: list[dict[str, str | list[str] | int]] = list()
-    lines = []
-    for k, v in conf.items():
-        if isinstance(v, str):
-            val = '"' + v.replace('"', '\\"') + '"'
-        elif isinstance(v, Password):
-            val = v.key()
-        elif isinstance(v, list):
-            assert all(
-                map(lambda i: isinstance(i, str), v)
-            ), "Only list of strings supported"
-            val = " ".join(v)
-        else:
-            val = str(v)
-        lines.append(f"{indent}{k}={val}")
-    return "\n".join(lines)
-
-
-networks = {}
 for path in list_networks():
     proc = subprocess.run(["pass", path], stdout=subprocess.PIPE)
     proc.check_returncode()
@@ -104,61 +46,24 @@ for path in list_networks():
     raw = proc.stdout.decode()
     split = raw.split("\n")
 
-    password = Password(path, split[0])
+    password = split[0]
     data = yaml.safe_load("\n".join(split[1:])) or dict()
-    # print(path, data)  # DEBUG
 
     # Helpers to prevent repetition
     suffixes = data.pop("suffixes", [""])
-    data.setdefault("key_mgmt", ["WPA-PSK"] if password.exists() else ["NONE"])
+    data.setdefault("key_mgmt", ["WPA-PSK"] if password else ["NONE"])
     if password:
         if any(map(lambda m: "PSK" in m.split("-"), data["key_mgmt"])):
             data["psk"] = password
-        if "NONE" in data["key_mgmt"]:
-            data["wep_key0"] = password
         if any(map(lambda m: "EAP" in m.split("-"), data["key_mgmt"])):
             data["password"] = password
     assert "ssid" in data, f"{path}: Missing SSID"
-
+    data.setdefault("disabled", 0)
-    # # Output wpa_supplicant conf, for debug
-    # for suffix in suffixes:
-    #     wpas = data.copy()
-    #     wpas["ssid"] += suffix
-    #     print(f"# {path}")
-    #     print("network={")
-    #     print(format_wpa_supplicant_conf(wpas, indent="    "))
-    #     print("}")
-    #     print()
-
-    # Convert to nix configuration
-    ssid = data.pop("ssid")
-    network = {}
-    key_mgmt = data.pop("key_mgmt", None)
-    psk = data.pop("psk", None)
-    priority = data.pop("priority", None)
-    # No support for hidden
-    # No support for extraConfig (all is assumed to be auth)
-    if key_mgmt:
-        network["authProtocols"] = key_mgmt
-    if psk:
-        network["psk"] = psk.key()
-        if data:
-            raise NotImplementedError(
-                f"{path}: Unhandled non-auth extra: {data}"
-            )
-    else:
-        if data:
-            network["auth"] = format_wpa_supplicant_conf(data)
-    if priority:
-        network["priority"] = int(priority)
 
     for suffix in suffixes:
-        networks[ssid + suffix] = network
+        network = data.copy()
+        network["ssid"] += suffix
+        networks.append(network)
 
 with open("wireless_networks.json", "w") as fd:
     json.dump(networks, fd, indent=4)
-
-with open("wireless_networks.env", "w") as fd:
-    if SEPARATE_PASSWORDS:
-        for k, v in Password.vars().items():
-            print(f'{k}="{v}"', file=fd)