stockholm/lib/krebs/genipv6.nix

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lib:
with lib;
let {
body = netname: subnetname: suffixSpec: rec {
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address = let
suffix' =
if hasEmptyGroup (parseAddress suffix)
then suffix
else joinAddress "::" suffix;
in
checkAddress addressLength (joinAddress subnetPrefix suffix');
addressCIDR = "${address}/${toString addressLength}";
addressLength = 128;
inherit netname;
netCIDR = "${netAddress}/${toString netPrefixLength}";
netAddress = joinAddress netPrefix "::";
netHash = toString {
retiolum = 0;
wirelum = 1;
}.${netname};
netPrefix = "42:${netHash}";
netPrefixLength = {
retiolum = 32;
wirelum = 32;
}.${netname};
inherit subnetname;
subnetCIDR = "${subnetAddress}/${toString subnetPrefixLength}";
subnetAddress = joinAddress subnetPrefix "::";
subnetHash = simplify (hash 4 subnetname);
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subnetPrefix = joinAddress netPrefix subnetHash;
subnetPrefixLength = netPrefixLength + 16;
suffix = getAttr (typeOf suffixSpec) {
set =
concatMapStringsSep
":"
simplify
(stringToGroupsOf 4 (hash (suffixLength / 8) suffixSpec.hostName));
string = suffixSpec;
};
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suffixLength = addressLength - subnetPrefixLength;
};
# Split string into list of chunks where each chunk is at most n chars long.
# The leftmost chunk might shorter.
# Example: stringToGroupsOf "123456" -> ["12" "3456"]
stringToGroupsOf = n: s: let
acc =
foldl'
(acc: c: if stringLength acc.chunk < n then {
chunk = acc.chunk + c;
chunks = acc.chunks;
} else {
chunk = c;
chunks = acc.chunks ++ [acc.chunk];
})
{
chunk = "";
chunks = [];
}
(stringToCharacters s);
in
filter (x: x != []) ([acc.chunk] ++ acc.chunks);
simplify = s: head (match "0*(.+)" s);
hash = n: s: substring 0 n (hashString "sha256" s);
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dropLast = n: xs: reverseList (drop n (reverseList xs));
takeLast = n: xs: reverseList (take n (reverseList xs));
hasEmptyPrefix = xs: take 2 xs == ["" ""];
hasEmptySuffix = xs: takeLast 2 xs == ["" ""];
hasEmptyInfix = xs: any (x: x == "") (trimEmpty 2 xs);
hasEmptyGroup = xs:
any (p: p xs) [hasEmptyPrefix hasEmptyInfix hasEmptySuffix];
ltrimEmpty = n: xs: if hasEmptyPrefix xs then drop n xs else xs;
rtrimEmpty = n: xs: if hasEmptySuffix xs then dropLast n xs else xs;
trimEmpty = n: xs: rtrimEmpty n (ltrimEmpty n xs);
parseAddress = splitString ":";
formatAddress = concatStringsSep ":";
check = s: c: if !c then throw "${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);
}