nixos-config/lib/ip.nix

64 lines
2.1 KiB
Nix

{ pkgs ? import <nixpkgs> {}, ... }:
with pkgs.lib;
let
joinString = concatStringsSep;
pow = x: e: if (e == 0) then 1 else x * (pow x (e - 1));
generateNBits = n: let
helper = n: c: if (c == n) then pow 2 c else (pow 2 c) + (helper n (c + 1));
in if (n <= 0) then throw "Can't generate 0 or fewer bits" else helper (n - 1) 0;
rightPadBits = int: bits: bitOr int (generateNBits bits);
reverseIpv4 = ip: joinString "." (reverseList (splitString "." ip));
intToBinaryList = int: let
helper = int: cur: let
curExp = pow 2 cur;
in if (curExp > int) then
[]
else
[(if ((bitAnd curExp int) > 0) then 1 else 0)] ++ (helper int (cur + 1));
in reverseList (helper int 0);
leftShift = int: n: int * (pow 2 n);
rightShift = int: n: int / (pow 2 n);
in rec {
ipv4ToInt = ip: let
els = map toInt (reverseList (splitString "." ip));
in foldr (a: b: a + b) 0 (imap0 (i: el: (leftShift el (i * 8))) els);
intToIpv4 = int: joinString "." (map (i: toString (bitAnd (rightShift int (i * 8)) 255)) [ 3 2 1 0 ]);
maskFromV32Network = network: let
fullMask = ipv4ToInt "255.255.255.255";
insignificantBits = 32 - (getNetworkMask network);
in intToIpv4 (leftShift (rightShift fullMask insignificantBits) insignificantBits);
networkMinIp = network: intToIpv4 (1 + (ipv4ToInt (getNetworkBase network)));
networkMaxIp = network: intToIpv4 (rightPadBits (ipv4ToInt (getNetworkBase network)) (32 - (getNetworkMask network)));
# To avoid broadcast IP...
networkMaxButOneIp = network: intToIpv4 ((rightPadBits (ipv4ToInt (getNetworkBase network)) (32 - (getNetworkMask network))) - 1);
ipv4OnNetwork = ip: network: let
ip-int = ipv4ToInt ip;
net-min = networkMinIp network;
net-max = networkMaxIp network;
in
(ip-int >= networkMinIp) && (ip-int <= networkMaxIp);
getNetworkMask = network: toInt (elemAt (splitString "/" network) 1);
getNetworkBase = network: let
ip = elemAt (splitString "/" network) 0;
insignificantBits = 32 - (getNetworkMask network);
in intToIpv4 (leftShift (rightShift (ipv4ToInt ip) insignificantBits) insignificantBits);
}