From e8ea72d0393c90a13921407ed7998efdf4263b76 Mon Sep 17 00:00:00 2001
From: Gregor Kleen <gkleen@yggdrasil.li>
Date: Sat, 9 Oct 2021 10:57:24 +0200
Subject: yggdrasil-wg: ...

---
 modules/yggdrasil-wg/default.nix | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

(limited to 'modules/yggdrasil-wg')

diff --git a/modules/yggdrasil-wg/default.nix b/modules/yggdrasil-wg/default.nix
index 1fd7092c..9c58c9fe 100644
--- a/modules/yggdrasil-wg/default.nix
+++ b/modules/yggdrasil-wg/default.nix
@@ -6,6 +6,7 @@ let
   listenPort = 51820;
   subnet = "2a03:4000:52:ada:1";
   subnetLength = 80;
+  hostLength = subnetLength + 16;
 
   links = [
     { from = "vidhar";
@@ -21,7 +22,16 @@ let
       dynamicEndpointRefreshSeconds = 86400;
     }
   ];
-  hostLength = subnetLength + 16;
+  routes = [
+    { from = "sif";
+      to = "vidhar";
+      via = "surtr";
+    }
+    { from = "vidhar";
+      to = "sif";
+      via = "surtr";
+    }
+  ];
   hostIPs = {
     surtr = ["${subnet}::/${toString hostLength}"];
     vidhar = ["${subnet}:1::/${toString hostLength}"];
@@ -35,11 +45,12 @@ let
   privateKeyPath = mkPrivateKeyPath hostName;
   inNetwork = pathExists privateKeyPath && pathExists publicKeyPath;
   hostLinks = filter ({ from, to, ... }: from == hostName || to == hostName) links;
+  hostRoutes = filter ({ from, to, ... }: from == hostName || to == hostName) routes;
   linkToPeer = opts@{from, to, ...}:
     let
       other = if from == hostName then to else from;
     in {
-      allowedIPs = hostIPs.${other};
+      allowedIPs = hostIPs.${other} ++ concatMap (rArgs: if rArgs.from != hostName || rArgs.via != to then [] else hostIPs.${rArgs.to}) routes;
       publicKey = trim (readFile (mkPublicKeyPath other));
     } // (optionalAttrs (from == hostName) (filterAttrs (n: _v: !(elem n ["from" "to" "endpointHost"])) opts // optionalAttrs (opts ? "endpointHost") { endpoint = "${opts.endpointHost}:${toString listenPort}"; }));
 
@@ -64,7 +75,8 @@ in {
         peers = map linkToPeer hostLinks;
         privateKeyFile = config.sops.secrets."yggdrasil-wg.priv".path;
         postSetup = ''
-          ${pkgs.iproute2}/bin/ip route replace "${subnet}::/${toString subnetLength}" dev "yggdrasil" table "main"
+          ${concatMapStringsSep "\n" (linkArgs: let other = if linkArgs.from == hostName then linkArgs.to else linkArgs.from; in concatMapStringsSep "\n" (otherIP: "ip route replate \"${otherIP}\" dev \"yggdrasil\" table \"main\"") hostIPs.${other}) hostLinks}
+          ${concatMapStringsSep "\n" (routeArgs: let other = if routeArgs.from == hostName then routeArgs.to else routeArgs.from; in concatMapStringsSep "\n" (otherIP: concatMapStringsSep "\n" (viaIP: "ip route replate \"${otherIP}\" via \"${viaIP}\" dev \"yggdrasil\" table \"main\"") hostIPs.${routeArgs.via}) hostIPs.${other}) hostRoutes}
         '';
       };
     };
@@ -77,5 +89,9 @@ in {
     };
 
     networking.hosts = mkIf inNetwork (listToAttrs (concatMap ({name, value}: map (ip: nameValuePair (stripSubnet ip) ["${name}.yggdrasil"]) value) (mapAttrsToList nameValuePair hostIPs)));
+
+    boot.kernel.sysctl = mkIf (any ({via, ...}: via == hostName) routes) {
+      "net.ipv6.conf.yggdrasil.forwarding" = 1;
+    };
   };
 }
-- 
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