91 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			91 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
# /etc files related to networking, such as /etc/services.
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{ config, lib, pkgs, ... }:
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with lib;
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let
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  cfg = config.networking;
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in
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{
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  options = {
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    networking.extraHosts = lib.mkOption {
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      type = types.lines;
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      default = "";
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      example = "192.168.0.1 lanlocalhost";
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      description = ''
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        Additional entries to be appended to <filename>/etc/hosts</filename>.
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      '';
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    };
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    networking.dnsSingleRequest = lib.mkOption {
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      type = types.bool;
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      default = false;
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      description = ''
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        Recent versions of glibc will issue both ipv4 (A) and ipv6 (AAAA)
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        address queries at the same time, from the same port. Sometimes upstream
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        routers will systemically drop the ipv4 queries. The symptom of this problem is
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        that 'getent hosts example.com' only returns ipv6 (or perhaps only ipv4) addresses. The
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        workaround for this is to specify the option 'single-request' in
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        /etc/resolv.conf. This option enables that.
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      '';
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    };
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  };
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  config = {
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    environment.etc =
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      { # /etc/services: TCP/UDP port assignments.
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        "services".source = pkgs.iana_etc + "/etc/services";
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        # /etc/protocols: IP protocol numbers.
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        "protocols".source  = pkgs.iana_etc + "/etc/protocols";
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        # /etc/rpc: RPC program numbers.
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        "rpc".source = pkgs.glibc + "/etc/rpc";
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        # /etc/hosts: Hostname-to-IP mappings.
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        "hosts".text =
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          ''
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            127.0.0.1 localhost
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            ${optionalString cfg.enableIPv6 ''
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              ::1 localhost
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            ''}
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            ${cfg.extraHosts}
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          '';
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        # /etc/resolvconf.conf: Configuration for openresolv.
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        "resolvconf.conf".text =
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            ''
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              # This is the default, but we must set it here to prevent
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              # a collision with an apparently unrelated environment
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              # variable with the same name exported by dhcpcd.
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              interface_order='lo lo[0-9]*'
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            '' + optionalString config.services.nscd.enable ''
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              # Invalidate the nscd cache whenever resolv.conf is
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              # regenerated.
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              libc_restart='${pkgs.systemd}/bin/systemctl try-restart --no-block nscd.service'
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            '' + optionalString cfg.dnsSingleRequest ''
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              # only send one DNS request at a time
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              resolv_conf_options='single-request'
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            '' + optionalString config.services.bind.enable ''
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              # This hosts runs a full-blown DNS resolver.
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              name_servers='127.0.0.1'
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            '';
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      };
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    # The ‘ip-up’ target is started when we have IP connectivity.  So
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    # services that depend on IP connectivity (like ntpd) should be
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    # pulled in by this target.
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    systemd.targets.ip-up.description = "Services Requiring IP Connectivity";
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  };
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}
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