2 files changed, 112 insertions, 0 deletions
diff --git a/lib/krebs/default.nix b/lib/krebs/default.nix
new file mode 100644
index 000000000..c9d9bef63
--- /dev/null
+++ b/lib/krebs/default.nix
@@ -0,0 +1,3 @@
+lib:
+with lib;
+mapNixDir (flip import lib) ./.
diff --git a/lib/krebs/genipv6.nix b/lib/krebs/genipv6.nix
new file mode 100644
index 000000000..22a23fcef
--- /dev/null
+++ b/lib/krebs/genipv6.nix
@@ -0,0 +1,109 @@
+lib:
+with lib;
+let {
+  body = netname: subnetname: suffixSpec: rec {
+    address = let
+      suffix' = prependZeros suffixLength suffix;
+    in
+      normalize-ip6-addr
+        (checkAddress addressLength (joinAddress subnetPrefix suffix'));
+    addressCIDR = "${address}/${toString addressLength}";
+    addressLength = 128;
+
+    inherit netname;
+    netCIDR = "${netAddress}/${toString netPrefixLength}";
+    netAddress =
+      normalize-ip6-addr (appendZeros addressLength netPrefix);
+    netHash = toString {
+      retiolum = 0;
+      wiregrill = 1;
+    }.${netname};
+    netPrefix = "42:${netHash}";
+    netPrefixLength = {
+      retiolum = 32;
+      wiregrill = 32;
+    }.${netname};
+
+    inherit subnetname;
+    subnetCIDR = "${subnetAddress}/${toString subnetPrefixLength}";
+    subnetAddress =
+      normalize-ip6-addr (appendZeros addressLength subnetPrefix);
+    subnetHash = hashToLength 4 subnetname;
+    subnetPrefix = joinAddress netPrefix subnetHash;
+    subnetPrefixLength = netPrefixLength + 16;
+
+    suffix = getAttr (typeOf suffixSpec) {
+      set =
+        concatStringsSep
+          ":"
+          (stringToGroupsOf
+            4
+            (hashToLength (suffixLength / 4) suffixSpec.hostName));
+      string = suffixSpec;
+    };
+    suffixLength = addressLength - subnetPrefixLength;
+  };
+
+  appendZeros = n: s: let
+    n' = n / 16;
+    zeroCount = n' - length parsedaddr;
+    parsedaddr = parseAddress s;
+  in
+    formatAddress (parsedaddr ++ map (const "0") (range 1 zeroCount));
+
+  prependZeros = n: s: let
+    n' = n / 16;
+    zeroCount = n' - length parsedaddr;
+    parsedaddr = parseAddress s;
+  in
+    formatAddress (map (const "0") (range 1 zeroCount) ++ parsedaddr);
+
+  hasEmptyPrefix = xs: take 2 xs == ["" ""];
+  hasEmptySuffix = xs: takeLast 2 xs == ["" ""];
+  hasEmptyInfix = xs: any (x: x == "") (trimEmpty 2 xs);
+
+  hasEmptyGroup = xs:
+    any (p: p xs) [hasEmptyPrefix hasEmptyInfix hasEmptySuffix];
+
+  ltrimEmpty = n: xs: if hasEmptyPrefix xs then drop n xs else xs;
+  rtrimEmpty = n: xs: if hasEmptySuffix xs then dropLast n xs else xs;
+  trimEmpty = n: xs: rtrimEmpty n (ltrimEmpty n xs);
+
+  parseAddress = splitString ":";
+  formatAddress = concatStringsSep ":";
+
+  check = s: c: if !c then throw "${s}" else true;
+
+  checkAddress = maxaddrlen: addr: let
+    parsedaddr = parseAddress addr;
+    normalizedaddr = trimEmpty 1 parsedaddr;
+  in
+    assert (check "address malformed; lone leading colon: ${addr}" (
+      head parsedaddr == "" -> tail (take 2 parsedaddr) == ""
+    ));
+    assert (check "address malformed; lone trailing colon ${addr}" (
+      last parsedaddr == "" -> head (takeLast 2 parsedaddr) == ""
+    ));
+    assert (check "address malformed; too many successive colons: ${addr}" (
+      length (filter (x: x == "") normalizedaddr) > 1 -> addr == [""]
+    ));
+    assert (check "address malformed: ${addr}" (
+      all (test "[0-9a-f]{0,4}") parsedaddr
+    ));
+    assert (check "address is too long: ${addr}" (
+      length normalizedaddr * 16 <= maxaddrlen
+    ));
+    addr;
+
+  joinAddress = prefix: suffix: let
+    parsedPrefix = parseAddress prefix;
+    parsedSuffix = parseAddress suffix;
+    normalizePrefix = rtrimEmpty 2 parsedPrefix;
+    normalizeSuffix = ltrimEmpty 2 parsedSuffix;
+    delimiter =
+      optional (length (normalizePrefix ++ normalizeSuffix) < 8 &&
+                (hasEmptySuffix parsedPrefix || hasEmptyPrefix parsedSuffix))
+               "";
+  in
+    formatAddress (normalizePrefix ++ delimiter ++ normalizeSuffix);
+}