From 7c06f30675ffe76b414ff121f88028c8a916d7c7 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Sat, 8 Jul 2023 23:07:07 +0100
Subject: [PATCH] set ipv6 wan address to that provided by dhcpv6

---
 examples/acquire-wan-address.fnl | 60 ++++++++++++++++++++++++++++++++
 examples/acquire-wan-address.nix |  8 +++++
 examples/rotuer.nix              | 19 +++++-----
 3 files changed, 77 insertions(+), 10 deletions(-)
 create mode 100644 examples/acquire-wan-address.fnl
 create mode 100644 examples/acquire-wan-address.nix

diff --git a/examples/acquire-wan-address.fnl b/examples/acquire-wan-address.fnl
new file mode 100644
index 00000000..cf28799b
--- /dev/null
+++ b/examples/acquire-wan-address.fnl
@@ -0,0 +1,60 @@
+(local { : merge : split : file-exists? : system } (require :anoia))
+(local svc (require :anoia.svc))
+
+;; structurally this is remarkably similar to
+;; acquire-lan-prefix.fnl. maybe they should be merged: if not then
+;; we could at least extract some common code
+
+;; (alternatively we could move all the parsing code into the thing in
+;; the odhcp service that *writes* this stuff)
+
+; (parse-address "2001:8b0:1111:1111:0:ffff:51bb:4cf2/128,3600,7200")
+
+
+(fn parse-address [str]
+  (fn parse-extra [s]
+    (let [out {}]
+      (each [name val (string.gmatch s ",(.-)=([^,]+)")]
+        (tset out name val))
+      out))
+  (let [(address len preferred valid extra)
+        (string.match str "(.-)/(%d+),(%d+),(%d+)(.*)$")]
+    (merge {: address : len : preferred : valid} (parse-extra extra))))
+
+(local bound-states
+       { :bound true
+         :rebound true
+         :informed true
+         :updated true
+         :ra-updated true
+         })
+
+(fn changes [old-addresses new-addresses]
+  (let [added {}
+        deleted {}
+        old-set (collect [_ v (ipairs old-addresses)] (values v true))
+        new-set (collect [_ v (ipairs new-addresses)] (values v true))]
+    (each [_ address (ipairs new-addresses)]
+      (if (not (. old-set address))
+          (table.insert added (parse-address address))))
+    (each [_ address (ipairs old-addresses)]
+      (if (not (. new-set address))
+          (table.insert deleted (parse-address address))))
+    (values added deleted)))
+
+(let [[state-directory wan-device] arg
+      dir (svc.open state-directory)]
+  (var addresses [])
+  (while true
+    (while (not (dir:ready?)) (dir:wait))
+    (if (. bound-states (dir:output "state"))
+        (let [new-addresses (split " " (dir:output "/addresses"))
+              (added deleted) (changes addresses new-addresses)]
+          (each [_ p (ipairs added)]
+            (system
+             (.. "ip address add " p.address "/" p.len " dev " wan-device)))
+          (each [_ p (ipairs deleted)]
+            (system
+             (.. "ip address del " p.address "/" p.len " dev " wan-device)))
+    	  (set addresses new-addresses)))
+    (dir:wait)))
diff --git a/examples/acquire-wan-address.nix b/examples/acquire-wan-address.nix
new file mode 100644
index 00000000..df55a543
--- /dev/null
+++ b/examples/acquire-wan-address.nix
@@ -0,0 +1,8 @@
+{
+  writeFennelScript
+, linotify
+, anoia
+}:
+writeFennelScript "acquire-wan-address"
+  [ linotify anoia ]
+  ./acquire-wan-address.fnl
diff --git a/examples/rotuer.nix b/examples/rotuer.nix
index bf5f2f8e..79734962 100644
--- a/examples/rotuer.nix
+++ b/examples/rotuer.nix
@@ -295,15 +295,6 @@ in rec {
       dependencies = [ services.wan ];
     };
 
-  # services.set-wan-address =
-  #   oneshot {
-  #     name = "set-wan-address";
-  #     # FIXME nasty bit of hardcoding - should get this from  dhcp6c
-  #     up = "ip address add 2001:8b0:1111:1111:0:ffff:51bb:4cf2/128 dev ppp0";
-  #     down = "ip address del 2001:8b0:1111:1111:0:ffff:51bb:4cf2/128 dev ppp0";
-  #     dependencies = [ services.dhcp6 ];
-  #   };
-
   services.acquire-lan-prefix =
     let script = pkgs.callPackage ./acquire-delegated-prefix.nix {  };
     in longrun {
@@ -312,6 +303,14 @@ in rec {
       dependencies = [ services.dhcp6 ];
     };
 
+  services.acquire-wan-address =
+    let script = pkgs.callPackage ./acquire-wan-address.nix {  };
+    in longrun {
+      name = "acquire-wan-address";
+      run = "${script} /run/service-state/dhcp6c.wan $(output ${services.wan} ifname)";
+      dependencies = [ services.dhcp6 ];
+    };
+
   services.default = target {
     name = "default";
     contents = with config.services; [
@@ -331,7 +330,7 @@ in rec {
       config.services.hostname
       dhcp6
       acquire-lan-prefix
-#      set-wan-address
+      acquire-wan-address
     ];
   };
   defaultProfile.packages = with pkgs; [