2 files changed, 55 insertions, 14 deletions

diff --git a/lib/default.nix b/lib/default.nix
index bf8c65e21..e352c7be9 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -29,8 +29,6 @@ let
       listToAttrs (map (name: nameValuePair name set.${name})
                        (filter (flip hasAttr set) names));
 
-    setAttr = name: value: set: set // { ${name} = value; };
-
     test = re: x: isString x && testString re x;
 
     testString = re: x: match re x != null;
@@ -109,7 +107,11 @@ let
           in
             a: concatStringsSep ":" (map f (splitString ":" a));
       in
-        a: toLower (group-zeros (drop-leading-zeros a));
+        a:
+          toLower
+            (if test ".*::.*" a
+              then a
+              else group-zeros (drop-leading-zeros a));
   };
 in
 
diff --git a/lib/krebs/genipv6.nix b/lib/krebs/genipv6.nix
index 27df8bf55..bf3ebab38 100644
--- a/lib/krebs/genipv6.nix
+++ b/lib/krebs/genipv6.nix
@@ -1,20 +1,18 @@
 lib:
 with lib;
 let {
-  body = netname: subnetname: suffix: rec {
+  body = netname: subnetname: suffixSpec: rec {
     address = let
-      suffix' =
-        if hasEmptyGroup (parseAddress suffix)
-          then suffix
-          else joinAddress "::" suffix;
+      suffix' = prependZeros suffixLength suffix;
     in
-      checkAddress addressLength (joinAddress subnetPrefix suffix');
+      normalize-ip6-addr
+        (checkAddress addressLength (joinAddress subnetPrefix suffix'));
     addressCIDR = "${address}/${toString addressLength}";
     addressLength = 128;
 
     inherit netname;
     netCIDR = "${netAddress}/${toString netPrefixLength}";
-    netAddress = joinAddress netPrefix "::";
+    netAddress = appendZeros netPrefixLength netPrefix;
     netHash = toString {
       retiolum = 0;
       wirelum = 1;
@@ -27,16 +25,57 @@ let {
 
     inherit subnetname;
     subnetCIDR = "${subnetAddress}/${toString subnetPrefixLength}";
-    subnetAddress = joinAddress subnetPrefix "::";
-    subnetHash = hash subnetname;
+    subnetAddress = appendZeros subnetPrefixLength subnetPrefix;
+    subnetHash = hash 4 subnetname;
     subnetPrefix = joinAddress netPrefix subnetHash;
     subnetPrefixLength = netPrefixLength + 16;
 
-    inherit suffix;
+    suffix = getAttr (typeOf suffixSpec) {
+      set =
+        concatStringsSep
+          ":"
+          (stringToGroupsOf 4 (hash (suffixLength / 4) suffixSpec.hostName));
+      string = suffixSpec;
+    };
     suffixLength = addressLength - subnetPrefixLength;
   };
 
-  hash = s: head (match "0*(.+)" (substring 0 4 (hashString "sha256" s)));
+  appendZeros = n: s: let
+    n' = n / 16;
+    zeroCount = n' - length parsedaddr;
+    parsedaddr = parseAddress s;
+  in
+    formatAddress (parsedaddr ++ map (const "0") (range 1 zeroCount));
+
+  prependZeros = n: s: let
+    n' = n / 16;
+    zeroCount = n' - length parsedaddr;
+    parsedaddr = parseAddress s;
+  in
+    formatAddress (map (const "0") (range 1 zeroCount) ++ parsedaddr);
+
+  # Split string into list of chunks where each chunk is at most n chars long.
+  # The leftmost chunk might shorter.
+  # Example: stringToGroupsOf "123456" -> ["12" "3456"]
+  stringToGroupsOf = n: s: let
+    acc =
+      foldl'
+        (acc: c: if stringLength acc.chunk < n then {
+          chunk = acc.chunk + c;
+          chunks = acc.chunks;
+        } else {
+          chunk = c;
+          chunks = acc.chunks ++ [acc.chunk];
+        })
+        {
+          chunk = "";
+          chunks = [];
+        }
+        (stringToCharacters s);
+  in
+    filter (x: x != []) ([acc.chunk] ++ acc.chunks);
+
+  hash = n: s: substring 0 n (hashString "sha256" s);
 
   dropLast = n: xs: reverseList (drop n (reverseList xs));
   takeLast = n: xs: reverseList (take n (reverseList xs));