From b519b48e8366a9f5e6ea591ad2e6c20a1461ed25 Mon Sep 17 00:00:00 2001
From: Joe Groocock <me@frebib.net>
Date: Thu, 25 Nov 2021 10:00:49 +0000
Subject: [PATCH] ssh: Add systemd ssh@ unit for persistent master connections

These rely on SSH configuring ControlMaster and ControlSocket for the
host so the connection can be reused.

Signed-off-by: Joe Groocock <me@frebib.net>
---
 ssh/askpass               | 13 +++++++++++++
 systemd/user/ssh@.service | 13 +++++++++++++
 2 files changed, 26 insertions(+)
 create mode 100755 ssh/askpass
 create mode 100644 systemd/user/ssh@.service

diff --git a/ssh/askpass b/ssh/askpass
new file mode 100755
index 0000000..45fb64b
--- /dev/null
+++ b/ssh/askpass
@@ -0,0 +1,13 @@
+#!/bin/sh -e
+
+if [ -z "$SSH_HOST" ]; then
+    >&2 echo 'Missing SSH_HOST variable'
+    exit 1
+fi
+
+case "$SSH_HOST" in
+    *)
+        echo 'Unknown SSH host'
+        exit 1
+        ;;
+esac
diff --git a/systemd/user/ssh@.service b/systemd/user/ssh@.service
new file mode 100644
index 0000000..236e436
--- /dev/null
+++ b/systemd/user/ssh@.service
@@ -0,0 +1,13 @@
+[Unit]
+Description=SSH persistent connection to %i
+
+[Service]
+Type=forking
+Slice=ssh.slice
+Environment=SSH_ASKPASS=%E/ssh/askpass
+Environment=SSH_HOST=%i
+ExecStart=/usr/bin/ssh -fNT %i
+Restart=on-failure
+
+[Install]
+WantedBy=ssh.target