From 626a365f790f628dc8deff27b2296545f239d3fe Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Wed, 1 Mar 2023 17:55:52 +0000
Subject: [PATCH] replace waitup with more generally useful ifwait

* wait for $interface present before ip link set up dev
* wait for wlan0 running before adding to bridge
---
 overlay.nix                               |  2 +-
 pkgs/ifwait/.#README                      |  1 +
 pkgs/{waitup => ifwait}/default.nix       | 13 +++---
 pkgs/ifwait/ifwait.fnl                    | 52 +++++++++++++++++++++++
 pkgs/{waitup => ifwait}/waitup.fnl        |  8 ++--
 pkgs/liminix-tools/networking/default.nix |  2 +
 rotuer.nix                                | 18 +++-----
 7 files changed, 75 insertions(+), 21 deletions(-)
 create mode 120000 pkgs/ifwait/.#README
 rename pkgs/{waitup => ifwait}/default.nix (60%)
 create mode 100644 pkgs/ifwait/ifwait.fnl
 rename pkgs/{waitup => ifwait}/waitup.fnl (90%)

diff --git a/overlay.nix b/overlay.nix
index a77dcbf..7ec77e4 100644
--- a/overlay.nix
+++ b/overlay.nix
@@ -87,7 +87,7 @@ final: prev: {
   };
 
   netlink-lua = final.callPackage ./pkgs/netlink-lua {};
-  waitup = final.callPackage ./pkgs/waitup {};
+  ifwait = final.callPackage ./pkgs/ifwait {};
 
   serviceFns = final.writeText "service-fns.sh" ''
     output() { cat $1/.outputs/$2; }
diff --git a/pkgs/ifwait/.#README b/pkgs/ifwait/.#README
new file mode 120000
index 0000000..c1c90e4
--- /dev/null
+++ b/pkgs/ifwait/.#README
@@ -0,0 +1 @@
+dan@noetbook.911352349782478447
\ No newline at end of file
diff --git a/pkgs/waitup/default.nix b/pkgs/ifwait/default.nix
similarity index 60%
rename from pkgs/waitup/default.nix
rename to pkgs/ifwait/default.nix
index 0639c7c..ce9ba85 100644
--- a/pkgs/waitup/default.nix
+++ b/pkgs/ifwait/default.nix
@@ -9,21 +9,22 @@ let
   netlink = netlink-lua.override {inherit lua;};
   fennel = lua.pkgs.fennel;
 in stdenv.mkDerivation rec {
-  pname = "waitup";
+  pname = "ifwait";
   version = "1";
+  phases = [ "installPhase" ];
 
-  buildInputs = [ lua netlink-lua ];
-  nativeBuildInputs = [ makeWrapper  fennel ];
+  buildInputs = [ lua netlink ];
+  nativeBuildInputs = [ makeWrapper fennel ];
 
-  src = ./.;
+  LUA_CPATH = "${netlink}/lib/lua/${lua.luaversion}/\?.so"; # for nix-shell
 
   installPhase = ''
     mkdir -p $out/bin $out/lib
-    fennel --compile  ${./waitup.fnl} > $out/lib/waitup.lua
+    fennel --compile  ${./ifwait.fnl} > $out/lib/${pname}.lua
 
     makeWrapper ${lua}/bin/lua $out/bin/${pname} \
       --prefix LUA_CPATH ";" ${netlink}/lib/lua/${lua.luaversion}/\?.so \
-      --add-flags $out/lib/waitup.lua
+      --add-flags $out/lib/${pname}.lua
   '';
 }
 
diff --git a/pkgs/ifwait/ifwait.fnl b/pkgs/ifwait/ifwait.fnl
new file mode 100644
index 0000000..36dd3e7
--- /dev/null
+++ b/pkgs/ifwait/ifwait.fnl
@@ -0,0 +1,52 @@
+(local netlink (require :netlink))
+(local sock (netlink.socket))
+
+; (local { : view} (require :fennel))
+
+(fn assoc [tbl k v]
+  (tset tbl k v)
+  tbl)
+
+(fn parse-args [args]
+  (match args
+    ["-v" & rest]  (assoc (parse-args rest) :verbose true)
+    ["-t" timeout & rest] (assoc (parse-args rest) :timeout (tonumber timeout))
+    [linkname "up"] {:link linkname :expecting "up"}
+    [linkname "running"] {:link linkname :expecting "running"}
+    [linkname "present"] {:link linkname :expecting "present"}
+    [linkname nil] {:link linkname :expecting "present"}
+    _  nil))
+
+(local parameters
+       (or
+        (parse-args arg)
+        (assert false (.. "Usage: " (. arg 0) " [-v] ifname [present|up|running]"))))
+
+(fn run-events [evs]
+  (each [_ v (ipairs evs)]
+    (let [got
+          (match v
+            ;; - up: Reflects the administrative state of the interface (IFF_UP)
+            ;; - running: Reflects the operational state (IFF_RUNNING).
+            {:event "newlink" :name parameters.link :up :yes :running :yes}
+            {:present true :up true :running true}
+
+            {:event "newlink" :name parameters.link :up :yes}
+            {:present :true :up true}
+
+            {:event "newlink" :name parameters.link}
+            {:present true }
+
+            _
+            {})]
+      (when (. got parameters.expecting)
+        (os.exit 0)))))
+
+
+(when parameters.verbose
+  (print (.. (. arg 0) ": waiting for "
+             parameters.link " to be " parameters.expecting)))
+
+(run-events (sock:query {:link true}))
+
+(while (sock:poll) (run-events (sock:event)))
diff --git a/pkgs/waitup/waitup.fnl b/pkgs/ifwait/waitup.fnl
similarity index 90%
rename from pkgs/waitup/waitup.fnl
rename to pkgs/ifwait/waitup.fnl
index e5675a8..1addf1c 100644
--- a/pkgs/waitup/waitup.fnl
+++ b/pkgs/ifwait/waitup.fnl
@@ -10,9 +10,11 @@
 (local stream (io.open (.. "/proc/self/fd/" fd) "w"))
 
 (fn notify-ready []
-  (stream:write "\n")
-  (print (.. (. arg 0) ": received netlink operstate up for " ifname))
-  (stream:close))
+  (when (= "file" (io.type stream))
+    (stream:write "\n")
+    (stream:close))
+  (print (.. (. arg 0) ": received netlink operstate up for " ifname)))
+
 
 (fn run-events [evs]
   (each [_ v (ipairs evs)]
diff --git a/pkgs/liminix-tools/networking/default.nix b/pkgs/liminix-tools/networking/default.nix
index b85b866..d0444ca 100644
--- a/pkgs/liminix-tools/networking/default.nix
+++ b/pkgs/liminix-tools/networking/default.nix
@@ -1,6 +1,7 @@
 {
   callPackage
 , liminix
+, ifwait
 , lib
 }:
 let
@@ -12,6 +13,7 @@ in {
           []
           ++ optional (type == "bridge")
             "ip link add name ${device} type bridge"
+          ++ ["${ifwait}/bin/ifwait -v ${device} present"]
           ++ ["ip link set up dev ${device}"]
           ++ optional (primary != null)
             "ip link set dev ${device} master ${primary.device}";
diff --git a/rotuer.nix b/rotuer.nix
index 9c2fef8..bb85897 100644
--- a/rotuer.nix
+++ b/rotuer.nix
@@ -19,7 +19,7 @@ let
     route;
   inherit (pkgs.liminix.services) oneshot longrun bundle target;
   inherit (pkgs)
-    waitup
+    ifwait
     serviceFns
     iptables;
 in rec {
@@ -122,17 +122,13 @@ in rec {
   };
 
   services.bridgewlan =
-    let waitup-wlan = longrun {
-          name = "waitup-wlan0";
-          run = "${waitup}/bin/waitup wlan0 10";
-          notification-fd = 10;
-          dependencies = [ services.wireless services.hostap ];
-        };
+    let dev = services.wireless.device;
     in oneshot {
-      name = "add-wlan-to-bridge";
-      up = "ip link set dev ${services.wireless.device} master ${services.lan.device}";
-      down = "ip link set dev ${services.wireless.device} nomaster";
-      dependencies = [ waitup-wlan  ];
+      name = "add-wlan2-to-bridge";
+      up = "${ifwait}/bin/ifwait -v ${dev} running && ip link set dev ${dev} master ${services.lan.device}";
+      down = "ip link set dev ${dev} nomaster";
+      dependencies = [ services.wireless ];
+    };
     };
 
   users.dnsmasq = {