summaryrefslogtreecommitdiff
path: root/modules/nixos/shadowsocks.nix
blob: 97eb17f99a5d19354e85424ffc8565a6042789dd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
{
  config,
  inputs,
  lib,
  pkgs,
  ...
}:
with lib; let
  cfg = config.nixfiles.modules.shadowsocks;
in {
  options.nixfiles.modules.shadowsocks = {
    enable = mkEnableOption "Shadowsocks";

    port = mkOption {
      type = with types; port;
      default = 8388;
      description = "Port.";
    };
  };

  config = mkIf cfg.enable {
    secrets.shadowsocks-json.file = "${inputs.self}/secrets/shadowsocks-json";

    services.fail2ban.jails.shadowsocks = {
      enabled = true;
      settings = {
        filter = "shadowsocks";
        inherit (cfg) port;
      };
    };

    systemd.services.shadowsocks = {
      description = "Shadowsocks";
      after = ["network.target"];
      wantedBy = ["multi-user.target"];
      serviceConfig = {
        DynamicUser = true;
        RuntimeDirectory = "shadowsocks";
        LoadCredential = "secret.json:${config.secrets.shadowsocks-json.path}";
        ExecStartPre = let
          mergeJson = let
            configFile = pkgs.writeText "config.json" (generators.toJSON {} {
              server = "::";
              server_port = cfg.port;
              # Can't really use AEAD-2022[1] just yet because it's not
              # supported by some[2] clients.
              #
              # [1]: https://shadowsocks.org/doc/sip022.html
              # [2]: https://github.com/shadowsocks/ShadowsocksX-NG/issues/1480
              # [2]: https://github.com/shadowsocks/shadowsocks-windows/issues/3448
              # method = "2022-blake3-chacha20-poly1305";
              method = "chacha20-ietf-poly1305";
              password = null; # Must be set as a secret.
              users = null; # Muse be set as a secret.
              fast_open = true;
              acl = pkgs.writeText "block-internal-access.acl" ''
                [outbound_block_list]
                0.0.0.0/8
                10.0.0.0/8
                100.64.0.0/10
                127.0.0.0/8
                169.254.0.0/16
                172.16.0.0/12
                192.0.0.0/24
                192.0.2.0/24
                192.88.99.0/24
                192.168.0.0/16
                198.18.0.0/15
                198.51.100.0/24
                203.0.113.0/24
                224.0.0.0/4
                240.0.0.0/4
                255.255.255.255/32
                ::1/128
                ::ffff:127.0.0.1/104
                fc00::/7
                fe80::/10
              '';
            });
          in
            pkgs.writeShellScript "meregeJson" ''
              ${getExe pkgs.jq} \
                -s '.[0] * .[1]' \
                ${configFile} \
                $CREDENTIALS_DIRECTORY/secret.json \
                >$RUNTIME_DIRECTORY/config.json
            '';
        in
          mergeJson;
        ExecStart = "${pkgs.shadowsocks-rust}/bin/ssserver --config \${RUNTIME_DIRECTORY}/config.json";
      };
    };

    environment.etc = mkIf config.nixfiles.modules.fail2ban.enable {
      "fail2ban/filter.d/shadowsocks.conf".text = ''
        [Definition]
        failregex = ^.*tcp handshake failed.*\[::ffff:<ADDR>\].*$
        ignoreregex =
        journalmatch = _SYSTEMD_UNIT=shadowsocks.service
      '';
    };

    networking.firewall = {
      allowedTCPPorts = [cfg.port];
      extraCommands = ''
        iptables -A nixos-fw -p tcp --syn --dport ${
          toString cfg.port
        } -m connlimit --connlimit-above 32 -j nixos-fw-refuse
      '';
    };

    # https://github.com/shadowsocks/shadowsocks/wiki/Optimizing-Shadowsocks
    boot.kernel.sysctl = {
      "net.core.rmem_max" = mkOverride 100 (pow 2 26);
      "net.core.wmem_max" = mkOverride 100 (pow 2 26);
      "net.core.netdev_max_backlog" = pow 2 18;
      "net.core.somaxconn" = pow 2 12;
      "net.ipv4.tcp_syncookies" = 1;
      "net.ipv4.tcp_tw_reuse" = mkOverride 100 1;
      "net.ipv4.tcp_tw_recycle" = mkOverride 100 0;
      "net.ipv4.tcp_fin_timeout" = mkOverride 100 30;
      "net.ipv4.tcp_keepalive_time" = 60 * 20;
      "net.ipv4.ip_local_port_range" = "10000 65000";
      "net.ipv4.tcp_max_syn_backlog" = pow 2 13;
      "net.ipv4.tcp_max_tw_buckets" = pow 2 12;
      "net.ipv4.tcp_fastopen" = mkOverride 100 3;
      "net.ipv4.tcp_mem" = mkOverride 100 (mkTcpMem 15 16 17);
      "net.ipv4.tcp_rmem" = mkOverride 100 (mkTcpMem 12 16 26);
      "net.ipv4.tcp_wmem" = mkOverride 100 (mkTcpMem 12 16 26);
      "net.ipv4.tcp_mtu_probing" = 1;
      "net.ipv4.tcp_congestion_control" = "hybla";
    };
  };
}