From 5184ff63f7beebd545fc6817f10d256d47e31c4b Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Mon, 4 Mar 2024 23:01:19 +0000
Subject: [PATCH] add anoia.nl, a convenience wrapper on netlink

---
 pkgs/anoia/nl.fnl      | 15 +++++++++++++++
 pkgs/anoia/test-nl.fnl |  7 +++++++
 pkgs/ifwait/ifwait.fnl | 40 ++++++++++++++++++----------------------
 3 files changed, 40 insertions(+), 22 deletions(-)
 create mode 100644 pkgs/anoia/nl.fnl
 create mode 100644 pkgs/anoia/test-nl.fnl

diff --git a/pkgs/anoia/nl.fnl b/pkgs/anoia/nl.fnl
new file mode 100644
index 0000000..8a65587
--- /dev/null
+++ b/pkgs/anoia/nl.fnl
@@ -0,0 +1,15 @@
+(local netlink (require :netlink))
+
+(local { : view } (require :fennel))
+
+(fn events [groups]
+  (let [sock (netlink.socket)]
+    (coroutine.wrap
+     (fn []
+       (each [_ e (ipairs (sock:query groups))]
+         (coroutine.yield e))
+       (while (sock:poll)
+         (each [_ e (ipairs (sock:event))]
+           (coroutine.yield e)))))))
+
+{ : events }
diff --git a/pkgs/anoia/test-nl.fnl b/pkgs/anoia/test-nl.fnl
new file mode 100644
index 0000000..07bf7b9
--- /dev/null
+++ b/pkgs/anoia/test-nl.fnl
@@ -0,0 +1,7 @@
+(local nl (require :anoia.nl))
+(local { : view } (require :fennel))
+
+(let [events (nl.events {:link true})]
+  (each [ev events]
+    (print "got one ")
+    (print (view ev))))
diff --git a/pkgs/ifwait/ifwait.fnl b/pkgs/ifwait/ifwait.fnl
index 36dd3e7..41e58bf 100644
--- a/pkgs/ifwait/ifwait.fnl
+++ b/pkgs/ifwait/ifwait.fnl
@@ -1,5 +1,4 @@
-(local netlink (require :netlink))
-(local sock (netlink.socket))
+(local nl (require :anoia.nl))
 
 ; (local { : view} (require :fennel))
 
@@ -22,31 +21,28 @@
         (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}
+(fn run-event [v]
+  (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 :up :yes}
+          {:present :true :up true}
 
-            {:event "newlink" :name parameters.link}
-            {:present true }
-
-            _
-            {})]
-      (when (. got parameters.expecting)
-        (os.exit 0)))))
+          {: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)))
+(each [event (nl.events {:link true})]
+  (run-event event))