From 1da6186814c94512c1cbc41f2dfd3b4ac7b2e44f Mon Sep 17 00:00:00 2001
From: tv <tv@krebsco.de>
Date: Wed, 18 Jan 2023 17:14:27 +0100
Subject: [PATCH] tv.wwan: init

---
 tv/3modules/default.nix |   1 +
 tv/3modules/wwan.nix    | 163 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 164 insertions(+)
 create mode 100644 tv/3modules/wwan.nix

diff --git a/tv/3modules/default.nix b/tv/3modules/default.nix
index c49f1582f..8c1066b71 100644
--- a/tv/3modules/default.nix
+++ b/tv/3modules/default.nix
@@ -14,5 +14,6 @@
     ./slock.nix
     ./x0vncserver.nix
     ./Xresources.nix
+    ./wwan.nix
   ];
 }
diff --git a/tv/3modules/wwan.nix b/tv/3modules/wwan.nix
new file mode 100644
index 000000000..703a903c9
--- /dev/null
+++ b/tv/3modules/wwan.nix
@@ -0,0 +1,163 @@
+with import ./lib;
+{ config, pkgs, ... }: {
+  options = {
+    tv.wwan.enable = mkEnableOption "tv.wwan";
+    tv.wwan.apn = mkOption {
+      type = with types; filename;
+    };
+    tv.wwan.device = mkOption {
+      type = with types; pathname;
+      default = "/dev/cdc-wdm0";
+    };
+    tv.wwan.interface = mkOption {
+      type = with types; nullOr filename;
+      default = null;
+    };
+    tv.wwan.operators = mkOption {
+      type = with types; listOf username;
+      default = [];
+    };
+    tv.wwan.secrets = mkOption {
+      type = with types; pathname;
+      default = toString <secrets/wwan.json>;
+      # format: {"pin1":number}
+    };
+  };
+  config = let
+    cfg = config.tv.wwan;
+  in mkIf cfg.enable {
+    systemd.services.wwan = {
+      environment = {
+        DEVICE = cfg.device;
+        SECRETS = "%d/secrets";
+      };
+      path = [
+        pkgs.busybox
+        pkgs.coreutils
+        pkgs.iproute2
+        pkgs.jq
+        (pkgs.symlinkJoin {
+          name = "uqmi-wrapper";
+          paths = [
+            (pkgs.writeDashBin "uqmi" ''
+              set -efu
+              exec ${pkgs.uqmi}/bin/uqmi --device="$DEVICE" "$@"
+            '')
+            pkgs.uqmi
+          ];
+        })
+        (pkgs.writeDashBin "get-interface" (
+          if cfg.interface != null then /* sh */ ''
+            echo ${cfg.interface}
+          '' else /* sh */ ''
+            exec ${pkgs.libqmi}/bin/qmicli -d "$DEVICE" -p --get-wwan-iface
+          ''
+        ))
+      ];
+      serviceConfig = {
+        LoadCredential = [
+          "secrets:${cfg.secrets}"
+        ];
+        Type = "oneshot";
+        RemainAfterExit = true;
+        SyslogIdentifier = "wwan";
+        ExecStart = pkgs.writeDash "tv.wwan.start.sh" ''
+          set -efu
+
+          interface=$(get-interface)
+
+          pin1_status=$(
+            uqmi --uim-get-sim-state |
+            jq -r '"\(.pin1_status)/\(.pin1_verify_tries)"'
+          )
+          case $pin1_status in
+            verified/*)
+              :
+              ;;
+            not_verified/3)
+              pin1=$(jq .pin1 "$SECRETS")
+              echo "verifying PIN1" >&2
+              if ! uqmi --uim-verify-pin1 "$pin1"; then
+                echo "error: failed to verify PIN1" >&2
+                exit 1
+              fi
+              ;;
+            not_verified/*)
+              echo "error: not trying to verify PIN1: not enough tries left" >&2
+              echo \
+                  "please check your configuration in ${cfg.secrets}" \
+                  " and verify if manually using:" \
+                  " ${pkgs.uqmi}/bin/uqmi -d $device --uim-veriy-pin1 XXXX" \
+                  >&2
+              exit 1
+          esac
+
+          raw_ip_path=/sys/class/net/$interface/qmi/raw_ip
+          raw_ip=$(cat "$raw_ip_path")
+          if [ "$raw_ip" != Y ]; then
+            echo "enabling raw-ip" >&2
+            if ! echo Y > "$raw_ip_path"; then
+              echo "error: failed to enable raw-ip" >&2
+              exit 1
+            fi
+          fi
+
+          operating_mode=$(uqmi --get-device-operating-mode | tr -d \")
+          case $operating_mode in
+            online)
+              :
+              ;;
+            persistent_low_power|low_power)
+              echo "settings device operating mode to online" >&2
+              uqmi --set-device-operating-mode online
+              operating_mode=$(uqmi --get-device-operating-mode | tr -d \")
+              if test "$operating_mode" != online; then
+                echo "error: failed to set device operating mode to online" >&2
+                exit 1
+              fi
+              ;;
+            *)
+              echo "error: don't know how to change device operating mode to online: $operating_mode" >&2
+              exit 1
+          esac
+
+          ip link set dev "$interface" up
+
+          data_status=$(uqmi --get-data-status | tr -d \")
+          case $data_status in
+            connected)
+              :
+              ;;
+            disconnected)
+              echo "starting network (APN=${cfg.apn})" >&2
+              sleep 1
+              uqmi \
+                  --start-network \
+                  --autoconnect \
+                  --apn ${cfg.apn} \
+                  --ip-family ipv4
+              sleep 1
+              ;;
+            *)
+              echo "error: unsupported data status: $data_status" >&2
+              exit 1
+          esac
+
+          udhcpc -q -f -n -i "$interface"
+        '';
+        Restart = "on-failure";
+        ExecStop = pkgs.writeDash "tv.wwan.stop.sh" ''
+          set -efu
+
+          interface=$(get-interface)
+
+          ip link set dev "$interface" down
+          uqmi --stop-network 0xFFFFFFFF --autoconnect
+          uqmi --sync
+          uqmi --set-device-operating-mode persistent_low_power
+        '';
+      };
+    };
+    tv.systemd.services.wwan.operators = cfg.operators;
+  };
+}