069c640f76
This commit introduces a new NixOS module `networking.getaddrinfo` to allow declarative configuration of `/etc/gai.conf`, which controls address selection behavior for `getaddrinfo(3)` as defined in RFC 3484 and RFC 6724.
121 lines
3.3 KiB
Nix
121 lines
3.3 KiB
Nix
{
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pkgs,
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lib,
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config,
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...
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}:
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let
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cfg = config.networking.getaddrinfo;
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formatTableEntries =
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tableName: table:
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if table == null then
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[ ]
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else
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lib.mapAttrsToList (cidr: val: "${tableName} ${cidr} ${toString val}") table;
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gaiConfText = lib.concatStringsSep "\n" (
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[
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"# Generated by NixOS module networking.getaddrinfo"
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"# Do not edit manually!"
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"reload ${if cfg.reload then "yes" else "no"}"
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]
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++ formatTableEntries "label" cfg.label
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++ formatTableEntries "precedence" cfg.precedence
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++ formatTableEntries "scopev4" cfg.scopev4
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);
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in
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{
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options.networking.getaddrinfo = {
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enable = lib.mkOption {
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type = lib.types.bool;
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default = pkgs.stdenv.hostPlatform.libc == "glibc";
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defaultText = lib.literalExpression ''
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pkgs.stdenv.hostPlatform.libc == "glibc"
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'';
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description = ''
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Enables custom address sorting configuration for {manpage}`getaddrinfo(3)` according to RFC 3484.
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This option generates a {file}`/etc/gai.conf` file to override the default address sorting tables,
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as described in {manpage}`gai.conf(5)`.
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This setting is only applicable when using the GNU C Library (glibc).
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It has no effect with other libc implementations.
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'';
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};
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reload = lib.mkOption {
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type = lib.types.bool;
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default = false;
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description = ''
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Determines whether a process should detect changes to the configuration file since it was last read.
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If enabled, the file is re-read automatically. This may cause issues in multithreaded applications
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and is generally discouraged.
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'';
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};
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label = lib.mkOption {
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type = lib.types.nullOr (lib.types.attrsOf lib.types.int);
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default = null;
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description = ''
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Adds entries to the label table, as described in section 2.1 of RFC 3484.
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If any label entries are provided, the glibc’s default label table is ignored.
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'';
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example = {
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"::/0" = 1;
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"2002::/16" = 2;
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"::/96" = 3;
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"::ffff:0:0/96" = 4;
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"fec0::/10" = 5;
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"fc00::/7" = 6;
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"2001:0::/32" = 7;
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};
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};
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precedence = lib.mkOption {
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type = lib.types.nullOr (lib.types.attrsOf lib.types.int);
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default = null;
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description = ''
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Similar to {option}`networking.getaddrinfo.label`, but this option
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defines entries for the precedence table instead.
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See sections 2.1 and 10.3 of RFC 3484 for details.
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Providing any value will disable the glibc's default precedence table.
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'';
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example = {
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"::1/128" = 50;
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"::/0" = 40;
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"2002::/16" = 30;
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"::/96" = 20;
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"::ffff:0:0/96" = 10;
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};
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};
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scopev4 = lib.mkOption {
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type = lib.types.nullOr (lib.types.attrsOf lib.types.int);
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default = null;
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description = ''
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Adds custom rules to the IPv4 scope table.
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By default, the scope IDs described in section 3.2 of RFC 6724 are used.
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Modifying these values is rarely necessary.
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'';
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example = {
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"::ffff:169.254.0.0/112" = 2;
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"::ffff:127.0.0.0/104" = 2;
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"::ffff:0.0.0.0/96" = 14;
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};
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};
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};
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config = lib.mkIf cfg.enable {
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environment.etc."gai.conf".text = gaiConfText;
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};
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meta.maintainers = with lib.maintainers; [ moraxyc ];
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}
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