pyrox.dev
1# /etc files related to networking, such as /etc/services.
2
3{ config, lib, pkgs, ... }:
4
5with lib;
6
7let
8
9 cfg = config.networking.resolvconf;
10
11 resolvconfOptions = cfg.extraOptions
12 ++ optional cfg.dnsSingleRequest "single-request"
13 ++ optional cfg.dnsExtensionMechanism "edns0";
14
15 configText =
16 ''
17 # This is the default, but we must set it here to prevent
18 # a collision with an apparently unrelated environment
19 # variable with the same name exported by dhcpcd.
20 interface_order='lo lo[0-9]*'
21 '' + optionalString config.services.nscd.enable ''
22 # Invalidate the nscd cache whenever resolv.conf is
23 # regenerated.
24 libc_restart='/run/current-system/systemd/bin/systemctl try-restart --no-block nscd.service 2> /dev/null'
25 '' + optionalString (length resolvconfOptions > 0) ''
26 # Options as described in resolv.conf(5)
27 resolv_conf_options='${concatStringsSep " " resolvconfOptions}'
28 '' + optionalString cfg.useLocalResolver ''
29 # This hosts runs a full-blown DNS resolver.
30 name_servers='127.0.0.1'
31 '' + cfg.extraConfig;
32
33in
34
35{
36 imports = [
37 (mkRenamedOptionModule [ "networking" "dnsSingleRequest" ] [ "networking" "resolvconf" "dnsSingleRequest" ])
38 (mkRenamedOptionModule [ "networking" "dnsExtensionMechanism" ] [ "networking" "resolvconf" "dnsExtensionMechanism" ])
39 (mkRenamedOptionModule [ "networking" "extraResolvconfConf" ] [ "networking" "resolvconf" "extraConfig" ])
40 (mkRenamedOptionModule [ "networking" "resolvconfOptions" ] [ "networking" "resolvconf" "extraOptions" ])
41 (mkRemovedOptionModule [ "networking" "resolvconf" "useHostResolvConf" ] "This option was never used for anything anyways")
42 ];
43
44 options = {
45
46 networking.resolvconf = {
47
48 enable = mkOption {
49 type = types.bool;
50 default = false;
51 internal = true;
52 description = ''
53 DNS configuration is managed by resolvconf.
54 '';
55 };
56
57 dnsSingleRequest = lib.mkOption {
58 type = types.bool;
59 default = false;
60 description = ''
61 Recent versions of glibc will issue both ipv4 (A) and ipv6 (AAAA)
62 address queries at the same time, from the same port. Sometimes upstream
63 routers will systemically drop the ipv4 queries. The symptom of this problem is
64 that 'getent hosts example.com' only returns ipv6 (or perhaps only ipv4) addresses. The
65 workaround for this is to specify the option 'single-request' in
66 /etc/resolv.conf. This option enables that.
67 '';
68 };
69
70 dnsExtensionMechanism = mkOption {
71 type = types.bool;
72 default = true;
73 description = ''
74 Enable the <code>edns0</code> option in <filename>resolv.conf</filename>. With
75 that option set, <code>glibc</code> supports use of the extension mechanisms for
76 DNS (EDNS) specified in RFC 2671. The most popular user of that feature is DNSSEC,
77 which does not work without it.
78 '';
79 };
80
81 extraConfig = mkOption {
82 type = types.lines;
83 default = "";
84 example = "libc=NO";
85 description = ''
86 Extra configuration to append to <filename>resolvconf.conf</filename>.
87 '';
88 };
89
90 extraOptions = mkOption {
91 type = types.listOf types.str;
92 default = [];
93 example = [ "ndots:1" "rotate" ];
94 description = ''
95 Set the options in <filename>/etc/resolv.conf</filename>.
96 '';
97 };
98
99 useLocalResolver = mkOption {
100 type = types.bool;
101 default = false;
102 description = ''
103 Use local DNS server for resolving.
104 '';
105 };
106
107 };
108
109 };
110
111 config = mkMerge [
112 {
113 networking.resolvconf.enable = !(config.environment.etc ? "resolv.conf");
114
115 environment.etc."resolvconf.conf".text =
116 if !cfg.enable then
117 # Force-stop any attempts to use resolvconf
118 ''
119 echo "resolvconf is disabled on this system but was used anyway:" >&2
120 echo "$0 $*" >&2
121 exit 1
122 ''
123 else configText;
124 }
125
126 (mkIf cfg.enable {
127 environment.systemPackages = [ pkgs.openresolv ];
128
129 systemd.services.resolvconf = {
130 description = "resolvconf update";
131
132 before = [ "network-pre.target" ];
133 wants = [ "network-pre.target" ];
134 wantedBy = [ "multi-user.target" ];
135 restartTriggers = [ config.environment.etc."resolvconf.conf".source ];
136
137 serviceConfig = {
138 Type = "oneshot";
139 ExecStart = "${pkgs.openresolv}/bin/resolvconf -u";
140 RemainAfterExit = true;
141 };
142 };
143
144 })
145 ];
146
147}