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lib.krebs.genipv6: can compute suffix from name

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tv 2018-12-11 21:37:52 +01:00
parent c36a52fb67
commit 46275b41ed
1 changed files with 34 additions and 4 deletions
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38
lib/krebs/genipv6.nix
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@ -1,7 +1,7 @@
lib:
with lib;
let {
body = netname: subnetname: suffix: rec {
body = netname: subnetname: suffixSpec: rec {
address = let
suffix' =
if hasEmptyGroup (parseAddress suffix)
@ -28,15 +28,45 @@ let {
inherit subnetname;
subnetCIDR = "${subnetAddress}/${toString subnetPrefixLength}";
subnetAddress = joinAddress subnetPrefix "::";
subnetHash = hash subnetname;
subnetHash = simplify (hash 4 subnetname);
subnetPrefix = joinAddress netPrefix subnetHash;
subnetPrefixLength = netPrefixLength + 16;
inherit suffix;
suffix = getAttr (typeOf suffixSpec) {
set =
concatMapStringsSep
":"
simplify
(stringToGroupsOf 4 (hash (suffixLength / 8) suffixSpec.hostName));
string = suffixSpec;
};
suffixLength = addressLength - subnetPrefixLength;
};
hash = s: head (match "0*(.+)" (substring 0 4 (hashString "sha256" s)));
# 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);
simplify = s: head (match "0*(.+)" s);
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));