nilsandClaude Sonnet 5.5
c395a43a78
lans.<n>.ipv6.address (a ULA /64) is assigned to the LAN, announced with an explicit prefix (networkd only announces the delegated prefix when prefix delegation is on) and advertised as RDNSS; Unbound listens and answers on it. Checked at build time: valid IPv6 CIDR, /64, fc00::/7. Covered by the onestick VM test (client SLAAC address, ping and DNS over the ULA, RA captured on the wire), assertion cases and a unit test for the /64 prefix helper. Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
82 lines
2.6 KiB
Nix
82 lines
2.6 KiB
Nix
# Small IPv4 helpers (addresses are plain 32-bit integers inside Nix).
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# Parsing returns null on malformed input so callers can turn that into an
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# assertion message instead of an evaluation crash.
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{ lib }:
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let
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pow2 = n: if n == 0 then 1 else 2 * pow2 (n - 1);
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in
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rec {
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ipv4 = rec {
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parse =
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s:
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let
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m = builtins.match "([0-9]{1,3})\\.([0-9]{1,3})\\.([0-9]{1,3})\\.([0-9]{1,3})" s;
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octets = map lib.toInt m;
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in
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if m == null || lib.any (o: o > 255) octets then
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null
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else
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lib.foldl' (acc: o: acc * 256 + o) 0 octets;
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# "10.0.0.5" or "10.0.0.0/24" -> { address (int); prefixLength }, or null.
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parseNet =
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s:
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let
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m = builtins.match "([0-9.]+)(/([0-9]{1,2}))?" s;
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address = if m == null then null else parse (builtins.elemAt m 0);
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prefixLength =
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if m == null || builtins.elemAt m 2 == null then 32 else lib.toInt (builtins.elemAt m 2);
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in
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if m == null || address == null || prefixLength > 32 then
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null
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else
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{ inherit address prefixLength; };
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format =
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n:
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lib.concatMapStringsSep "." (shift: toString (lib.mod (n / pow2 shift) 256)) [
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24
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16
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8
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0
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];
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netMask = prefixLength: 4294967295 - (pow2 (32 - prefixLength) - 1);
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# Network address (integer) of `address` under `prefixLength`.
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networkOf = address: prefixLength: builtins.bitAnd address (netMask prefixLength);
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# "192.168.10.1" /24 -> "192.168.10.0/24"
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cidr =
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address: prefixLength:
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"${format (networkOf (parse address) prefixLength)}/${toString prefixLength}";
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inSubnet =
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{ address, prefixLength }: ip: networkOf ip prefixLength == networkOf address prefixLength;
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# Whether two subnets share any address (one contains the other's network).
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overlaps =
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a: b:
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let
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p = lib.min a.prefixLength b.prefixLength;
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in
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networkOf a.address p == networkOf b.address p;
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};
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ipv6 = {
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# The first 64 bits of an address (any form, with or without a prefix
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# length) as a /64 prefix, e.g. fd2c:cdef:cde9::1/64 -> fd2c:cdef:cde9:0::/64.
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prefix64 =
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address:
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let
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bare = builtins.head (lib.splitString "/" address);
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halves = lib.splitString "::" bare;
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groups = s: lib.filter (g: g != "") (lib.splitString ":" s);
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head = groups (builtins.elemAt halves 0);
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tail = lib.optionals (lib.length halves > 1) (groups (builtins.elemAt halves 1));
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full = head ++ lib.replicate (8 - lib.length head - lib.length tail) "0" ++ tail;
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in
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"${lib.concatStringsSep ":" (lib.take 4 full)}::/64";
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};
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}
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