1 files changed, 120 insertions, 0 deletions

diff --git a/home-modules/autossh-proxy.nix b/home-modules/autossh-proxy.nix
new file mode 100644
index 00000000..46cf1838
--- /dev/null
+++ b/home-modules/autossh-proxy.nix
@@ -0,0 +1,120 @@
+{ lib, sysConfig, config, pkgs, ... }:
+
+let
+  cfg = config.programs.ssh.autosshProxies;
+in {
+  options = {
+    programs.ssh.autosshProxies = lib.mkOption {
+      type = lib.types.attrsOf (lib.types.submodule ({ name, config, ... }: {
+        options = {
+          port = lib.mkOption {
+            type = lib.types.port;
+          };
+
+          socksPort = lib.mkOption {
+            type = lib.types.port;
+            default = config.port - 1;
+          };
+
+          host = lib.mkOption {
+            type = lib.types.str;
+            default = name;
+          };
+
+          sshpassSecret = lib.mkOption {
+            type = lib.types.nullOr lib.types.str;
+          };
+
+          ProxyCommand = lib.mkOption {
+            type = lib.types.str;
+            readOnly = true;
+            default = "${lib.getExe pkgs.socat} - SOCKS4A:127.0.0.1:%h:%p,socksport=${toString config.port}";
+          };
+        };
+      }));
+    };
+  };
+
+  config = {
+    assertions = [
+      {
+        assertion = builtins.length (lib.unique (lib.concatMap (cfg: [cfg.port cfg.socksPort]) (builtins.attrValues cfg))) == builtins.length (builtins.attrValues cfg) * 2;
+        message = "autosshProxy ports are not unique";
+      }
+    ];
+
+    systemd.user.services = lib.mkMerge (map (cfg: {
+      "autossh-socks@${cfg.host}:${toString cfg.socksPort}" = {
+        Service = {
+          Type = "notify";
+          NotifyAccess = "all";
+          WorkingDirectory = "~";
+          Restart = "always";
+          RestartSec = "23s";
+          ExecStart = "${pkgs.writeScript "autossh" ''
+            #!${lib.getExe config.programs.zsh.package} -xe
+
+            host="''${1%:*}"
+            port="''${1#*:}"
+
+            typeset -a cmd
+            cmd=()
+
+            if [[ -n "''${SSHPASS_SECRET}" ]]; then
+              cmd+=(${lib.getExe' pkgs.sshpassSecret "sshpass-secret"})
+              cmd+=("''${(@s/:/)SSHPASS_SECRET}")
+              cmd+=(--)
+            fi
+
+            cmd+=(${lib.getExe' pkgs.openssh "ssh"} -vN -D 127.0.0.1:''${port} -o ControlPath=none -o ExitOnForwardFailure=yes -o ServerAliveCountMax=15 -o ServerAliveInterval=2 "''${host}")
+
+            ( exec -a "''${cmd[1]}" -- ''${cmd} ) &
+            pid=$!
+
+            newpid=""
+            i=200
+            while ! { newpid=$(${lib.getExe' pkgs.iproute2 "ss"} -HO -pln "src localhost sport ''${port}" | ${lib.getExe pkgs.gnused} -r 's/^.*pid=([0-9]+).*$/\1/'); [[ -n $newpid ]] }; do
+              if ! kill -0 "''${pid}"; then
+                wait "''${pid}"
+                exit $?
+              fi
+              [[ "''${i}" -gt 0 ]] || exit 1
+              i=$((''${i} - 1))
+              ${lib.getExe' pkgs.coreutils "sleep"} 0.1
+            done
+
+            ${lib.getExe' sysConfig.systemd.package "systemd-notify"} --pid=''${newpid} --ready
+          ''} \"%I\"";
+          Environment = lib.optional (cfg.sshpassSecret != null) "SSHPASS_SECRET=${cfg.sshpassSecret}";
+        };
+        Unit = {
+          StopWhenUnneeded = true;
+          StartLimitInterval = "180s";
+          StartLimitBurst = 7;
+        };
+      };
+      "proxy-to-autossh-socks@${toString cfg.port}" = {
+        Unit = {
+          BindsTo = ["autossh-socks@${cfg.host}:${toString cfg.socksPort}.service" "proxy-to-autossh-socks@${toString cfg.port}.socket"];
+          After = ["autossh-socks@${cfg.host}:${toString cfg.socksPort}.service" "proxy-to-autossh-socks@${toString cfg.port}.socket"];
+        };
+        Service = {
+          ExecStart = "${sysConfig.systemd.package}/lib/systemd/systemd-socket-proxyd --exit-idle-time=60s 127.0.0.1:${toString cfg.socksPort}";
+          Restart = "always";
+          RestartSec = "23s";
+        };
+      };
+    }) (builtins.attrValues cfg));
+    systemd.user.sockets = builtins.listToAttrs (map (cfg: lib.nameValuePair "proxy-to-autossh-socks@${toString cfg.port}" {
+      Socket = {
+        ListenStream = "%I";
+        TriggerLimitIntervalSec = 0;
+        PollLimitIntervalSec = "180s";
+        PollLimitBurst = 6;
+      };
+      Install = {
+        WantedBy = ["sockets.target"];
+      };
+    }) (builtins.attrValues cfg));
+  };
+}