From 42f9db1c24dc8c428095e864c7090c7d70a4c9af Mon Sep 17 00:00:00 2001
From: Matthias Kruk <m@m10k.eu>
Date: Thu, 25 Mar 2021 07:26:46 +0900
Subject: [PATCH] include/ssh: Add functions for handling SSH tunnels and
 proxies

SSH provides a clean way to open and close tunnels and proxies on demand
through control sockets, however keeping track of the control sockets can
be somewhat bothersome. This commit adds functions that provide an easy
way to open and close tunnels and proxies without the caller having to
bother with control sockets.
---
 include/ssh.sh | 157 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 157 insertions(+)
 create mode 100644 include/ssh.sh

diff --git a/include/ssh.sh b/include/ssh.sh
new file mode 100644
index 0000000..fe1d32c
--- /dev/null
+++ b/include/ssh.sh
@@ -0,0 +1,157 @@
+#!/bin/bash
+
+__init() {
+	if ! include "log"; then
+		return 1
+	fi
+
+	declare -xgr __ssh_socket_dir="$TOOLBOX_HOME/ssh"
+
+	return 0
+}
+
+_ssh_get_socket_dir() {
+	if ! mkdir -p "$__ssh_socket_dir" &> /dev/null; then
+		error "Could not create $__ssh_socket_dir"
+		return 1
+	fi
+
+	echo "$__ssh_socket_dir"
+	return 0
+}
+
+_ssh_tunnel_ctrl_socket_name() {
+	local host
+	local port
+	local lport
+
+	local sockdir
+
+	host="$1"
+	port="$2"
+	lport="$3"
+
+	if ! sockdir=$(_ssh_get_socket_dir); then
+		return 1
+	fi
+
+	echo "$sockdir/tunnel-$lport-$host-$port.sock"
+	return 0
+}
+
+_ssh_proxy_ctrl_socket_name() {
+	local host
+	local port
+
+	local sockdir
+
+	host="$1"
+	port="$2"
+
+	if ! sockdir=$(_ssh_get_socket_dir); then
+		return 1
+	fi
+
+	echo "$sockdir/proxy-$host-$port.sock"
+	return 0
+}
+
+ssh_tunnel_open() {
+	local tunnel_host
+	local tunnel_user
+	local remote_addr
+	local remote_port
+	local local_addr
+	local local_port
+
+	tunnel_host="$1"
+	tunnel_user="$2"
+	remote_addr="$3"
+        remote_port="$4"
+	local_addr="$5"
+	local_port="$6"
+
+	local ctrl_sock
+	local addrspec
+	local sshtarget
+
+	if ! ctrl_sock=$(_ssh_tunnel_ctrl_socket_name "$remote_addr" \
+						      "$remote_port" \
+						      "$local_port"); then
+		return 1
+	fi
+
+	addrspec="$local_addr:$local_port:$remote_addr:$remote_port"
+	sshtarget="$tunnel_user@$tunnel_host"
+
+	if ! ssh -M -S "$ctrl_sock" -fnNT -o "ExitOnForwardFailure=yes" \
+	     -L "$addrspec" "$sshtarget" > /dev/null; then
+		return 1
+	fi
+
+	echo "$ctrl_sock"
+	return 0
+}
+
+ssh_tunnel_close() {
+	local tunnel_host
+	local tunnel_user
+	local ctrl_sock
+
+	tunnel_host="$1"
+	tunnel_user="$2"
+	ctrl_sock="$3"
+
+	if ! ssh -S "$ctrl_sock" -O exit "$tunnel_user@$tunnel_host" &> /dev/null; then
+		return 1
+	fi
+
+	return 0
+}
+
+ssh_proxy_open() {
+	local proxy_host
+	local proxy_user
+	local local_addr
+	local local_port
+
+	local ctrl_sock
+	local addrspec
+	local sshtarget
+
+	proxy_host="$1"
+	proxy_user="$2"
+	local_addr="$3"
+	local_port="$4"
+
+	if ! ctrl_sock=$(_ssh_proxy_ctrl_socket_name "$local_addr" "$local_port"); then
+		return 1
+	fi
+
+	addrspec="$local_addr:$local_port"
+	sshtarget="$proxy_user@$proxy_host"
+
+	if ! ssh -M -S "$ctrl_sock" -fnNT -o "ExitOnForwardFailure=yes" \
+	     -D "$addrspec" "$sshtarget" > /dev/null; then
+		return 1
+	fi
+
+	echo "$ctrl_sock"
+	return 0
+}
+
+ssh_proxy_close() {
+	local proxy_host
+	local proxy_user
+	local ctrl_sock
+
+	proxy_host="$1"
+	proxy_user="$2"
+	ctrl_sock="$3"
+
+	if ! ssh -S "$ctrl_sock" -O exit "$proxy_user@$proxy_host" &> /dev/null; then
+		return 1
+	fi
+
+	return 0
+}
-- 
2.47.3