#!/bin/bash
-# Copyright (C) 2016 Ian Kelling
+# I, Ian Kelling, follow the GNU license recommendations at
+# https://www.gnu.org/licenses/license-recommendations.en.html. They
+# recommend that small programs, < 300 lines, be licensed under the
+# Apache License 2.0. This file contains or is part of one or more small
+# programs. If a small program grows beyond 300 lines, I plan to switch
+# its license to GPL.
+
+# Copyright 2024 Ian Kelling
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
[[ $EUID == 0 ]] || exec sudo -E "$BASH_SOURCE" "$@"
-case $1 in
- -h|--help|*)
- cat <<'EOF'
-usage: ${0##*/}
+usage() {
+ cat <<'EOF'
+usage: ${0##*/} [OPTIONS] [IPV6_ADDR/BITS]
+
+-4 Prefix of range for ipv4, default 10.8.0
+-6 IP6_NETWORK Do ip6 nat for this network. ipv6 will work without nat,
+ but you may want it in certain circumstances.
+-d Do not push dns
+-i INTERFACE_NAME name of tun interface
+-n NAME default = server. 2 servers on the same host need different names.
+-p PORT default 1194
+-r Do not push default route
+-s Do not start openvpn
+-h --help print help
+
+IPV6_ADDR/BITS Ipv6 address of the vpn interface.
+
+Sets up a vpn server which pushes gateway route and dns server so all
+traffic goes through the vpn. requires systemd, and might have some
+debian specific paths.
+
+For ipv6, we assume ipv6_addr routes to the server.
+
+You can save all the keys by storing /etc/openvpn/easy-rsa-NAME/keys, and
+the script will not generate them if it sees they exist already.
+
+For future updates to this script, this is a good place to
+take inspiration.
+https://github.com/angristan/openvpn-install/blob/master/openvpn-install.sh
-Sets up a vpn server which pushes gateway route and dns server
-so all traffic goes through the vpn. requires systemd,
-and might have some debian specific paths.
+Note: Uses GNU getopt options parsing style
EOF
- ;;
-esac
+ exit $1
+}
+
+dns=true
+route=true
+start=true
+ip4=10.8.0
+name=server
+temp=$(getopt -l help 4:6:di:n:p:rsh "$@") || usage 1
+eval set -- "$temp"
+while true; do
+ case $1 in
+ -4) ip4=$2; shift 2 ;;
+ -6) ip6net=$2; shift 2 ;;
+ -d) dns=false; shift ;;
+ -i) ifname=$2; shift 2 ;;
+ -n) name=$2; shift 2 ;;
+ -p) port=$2; shift 2 ;;
+ -r) route=false; shift ;;
+ -s) start=false; shift ;;
+ -h|--help) usage ;;
+ --) shift; break ;;
+ *) echo "$0: Internal error! unexpected args: $*" ; exit 1 ;;
+ esac
+done
+
+read -r ip6 ip6route <<<"$@"
+source /a/bin/distro-functions/src/package-manager-abstractions
-apt-get update
-# suggests get's us openssl & easy rsa
-apt-get install --install-suggests -y openvpn
-apt-get install -y uuid-runtime
-mkdir -p /etc/openvpn/easy-rsa/keys
-cd /etc/openvpn/easy-rsa
+pi-nostart openvpn openssl easy-rsa uuid-runtime
+
+if [[ -e /lib/systemd/system/openvpn-server@.service ]]; then
+ vpn_service=openvpn-server@$name
+else
+ vpn_service=openvpn@$name
+fi
+rsadir=/etc/openvpn/easy-rsa-$name
+mkdir -p $rsadir
+cd $rsadir
cp -r /usr/share/easy-rsa/* .
-source vars # dun care about setting cert cn etc from the non-example values
-./clean-all
-# accept default prompts
-echo -e '\n\n\n\n\n\n\n\n' | ./build-ca
-
-# This builds the server's key/cert. argument is the name of the file,
-# but it also is the default common name of the cert.
-# 'server' is the default name in our conf file for the name of the file
-# and I've seen no reason to change it.
-# Note, this is not idempotent.
-{ echo -e '\n\n\n\n\n\n\n\n\n\n'; sleep 1; echo -e 'y\ny\n'; } | ./build-key-server server
-./build-dh
-cp /usr/share/doc/openvpn/examples/sample-config-files/server.conf.gz /etc/openvpn/
-cp /etc/openvpn/easy-rsa/keys/{ca.crt,server.{crt,key},dh2048.pem} /etc/openvpn
-gzip -df /etc/openvpn/server.conf.gz
-sed -i --follow-symlinks 's/^dh dh1024.pem/dh dh2048.pem/' /etc/openvpn/server.conf
-
-teeu() {
- while read -r line; do
- grep -xFq "$line" "$1" || echo "$line" | tee -a "$1"
- done
-}
+if [[ -e openssl-1.0.0.cnf && ! -e openssl.cnf ]]; then
+ # there's a debian bug about this.
+ ln -s openssl-1.0.0.cnf openssl.cnf
+fi
+
+server_dir=/etc/openvpn/server
+mkdir -p $server_dir
+chmod 700 $server_dir
+conf=$server_dir/$name.conf
+
+
+new=true
+ca_origin=$rsadir/pki/ca.crt
+keyfiles=(
+ $rsadir/pki/private/$name.key
+ $rsadir/pki/issued/$name.crt
+)
+if [[ -e /etc/openvpn/easy-rsa/build-ca ]]; then
+ new=false
+ ca_origin=$rsadir/ca.crt
+ keyfiles=(
+ $rsadir/keys/$name.key
+ $rsadir/keys/$name.crt
+ )
+fi
+
+keys_exist=true
+for f in ${keyfiles[@]}; do
+ if [[ ! -e $f ]]; then
+ keys_exist=false
+ break
+ fi
+done
+
+f=$server_dir/dh2048.pem
+if [[ ! -e $f ]]; then
+ openssl dhparam -out $f 2048
+fi
+
+f=$server_dir/ta-$name.key
+if [[ ! -e $f ]]; then
+ openvpn --genkey --secret $server_dir/ta-$name.key
+fi
+
+
+if ! $keys_exist; then
+ # newer sample configs (post stretch) use ta.key. no harm making it for earlier oses
+ if $new; then
+ echo 'set_var EASYRSA_NS_SUPPORT "yes"' >vars
+ ./easyrsa init-pki
+ ./easyrsa --batch build-ca nopass
+ ./easyrsa --days=3650 build-server-full $name nopass
+ else
+ # dun care about settning cert cn etc from the non-example values
+ source vars
+ # doesnt exist in buster
+ ./clean-all # note: removes and creates /etc/openvpn/easy-rsa/keys
+ # accept default prompts
+ echo -e '\n\n\n\n\n\n\n\n' | ./build-ca
+
+ # This builds the server's key/cert. argument is the name of the file,
+ # but it also is the default common name of the cert.
+ # 'server' is the default name in our conf file for the name of the file
+ # and I've seen no reason to change it.
+ # Note, this is not idempotent.
+ { echo -e '\n\n\n\n\n\n\n\n\n\n'; sleep 1; echo -e 'y\ny\n'; } | ./build-key-server $name
+ ./build-dh
+ fi
+fi
+
+if [[ -e /usr/share/doc/openvpn/examples/sample-config-files/server.conf ]]; then
+ cat /usr/share/doc/openvpn/examples/sample-config-files/server.conf >$conf
+else
+ # pre-bullsye name
+ gzip -dc /usr/share/doc/openvpn/examples/sample-config-files/server.conf.gz >$conf
+fi
+
+cafile=$server_dir/ca-$name.crt
+cp $ca_origin $cafile
+cp ${keyfiles[@]} $server_dir
+# for legacy systems
+for f in ${keyfiles[@]} $cafile; do
+ ln -sf server/${f##*/} /etc/openvpn
+done
+
+cat >>$conf <<EOF
+
+# I cat an extra blank line to start because the example config does
+# not have a final newline. ....
+# not in example config, but openvpn outputs a warning about insecure
+# cipher without a setting like this (the default i can understand due
+# to compatibility issues, but not changing the example config... not
+# cool).
+# requires the same setting on the client side.
+cipher AES-256-CBC
+# just sets up the ability to have client specific configs
+client-config-dir /etc/openvpn/client-config
+
+# duplicate in newer sample configs
+tls-auth ta-$name.key 0 # This file is secret
+
+# depending on sample config, this may not be there, which means i can't
+# talk to $ip4.1, there might be some other way, but stretch's
+# sample config says:
+# Should be subnet (addressing via IP)
+# unless Windows clients v2.0.9 and lower have to
+# be supported (then net30, i.e. a /30 per client)
+# Defaults to net30 (not recommended)
+topology subnet
+
+status /var/log/openvpn/openvpn-status-$name.log
+ifconfig-pool-persist /var/log/openvpn/ipp-$name.txt
+ca ca-$name.crt
+cert $name.crt
+key $name.key
+client-config-dir /etc/openvpn/client-config-$name
+server $ip4.0 255.255.255.0
+EOF
+mkdir -p /etc/openvpn/client-config-$name
+
+# dh improve security,
+# remove comp-lzo to increase perf
+sed -i --follow-symlinks -f - $conf <<'EOF'
+s/^dh dh1024.pem/dh dh2048.pem/
+/^comp-lzo.*/d
+EOF
+
+
+if $dns; then
+ # Be the dns server for clients
+ cat >>$conf <<EOF
+push "dhcp-option DNS $ip4.1"
+EOF
+fi
+
+if [[ $ifname ]]; then
+ cat >>$conf <<EOF
+dev $ifname
+EOF
+fi
+
+if [[ $ip6 ]]; then
+ cat >>$conf <<EOF
+push tun-ipv6 # legacy option that flidas needs, has no harm.
+# the ::1 is not used, i just put a short valid address there
+ifconfig-ipv6 $ip6 ::1
+EOF
+
+ sed -i --follow-symlinks '/^ *net.ipv6.conf.all.forwarding=.*/d' /etc/sysctl.conf
+ cat >>/etc/sysctl.conf <<'EOF'
+net.ipv6.conf.all.forwarding=1
+EOF
+
+fi
+
+
+if $route; then
+ cat >>$conf <<'EOF'
# Be the default gateway for clients.
-teeu /etc/openvpn/server.conf <<'EOF'
push "redirect-gateway def1"
EOF
-
-# Be the dns server for clients
-teeu /etc/openvpn/server.conf <<'EOF'
-push "dhcp-option DNS 10.8.0.1"
+ if [[ $ip6 ]]; then
+ cat >>$conf <<'EOF'
+push "route-ipv6 2000::/3"
EOF
+ fi
+fi
+if [[ $port ]]; then
+ cat >>$conf <<EOF
+port $port
+EOF
+fi
+
-echo "1" > /proc/sys/net/ipv4/ip_forward
sed -i --follow-symlinks '/^ *net\.ipv4\.ip_forward=.*/d' /etc/sysctl.conf
-teeu /etc/sysctl.conf <<'EOF'
+cat >>/etc/sysctl.conf <<'EOF'
net.ipv4.ip_forward=1
EOF
+sysctl -p /etc/sysctl.conf
+gw=$(ip route | sed -rn 's/^default via .* dev (\S+).*/\1/p' | head -n1)
-gw=$(ip route | sed -rn 's/^default via .* dev (\S+).*/\1/p')
-
-sudo dd of=/etc/systemd/system/mynat.service <<EOF
-[Unit]
-Description=Turns on nat iptables setting
-
+d=/etc/systemd/system/$vpn_service.service.d
+mkdir -p $d
+f=$d/nat.conf
+cat >$f <<EOF
[Service]
-Type=oneshot
-RemainAfterExit=yes
-ExecStart=/sbin/iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -o $gw -j MASQUERADE
-ExecStop=/sbin/iptables -t nat -D POSTROUTING -s 10.8.0.0/24 -o $gw -j MASQUERADE
-
-[Install]
-WantedBy=multi-user.target
+ExecStartPre=/sbin/iptables -t nat -A POSTROUTING -s $ip4.0/24 -o $gw -j MASQUERADE
+ExecStopPost=/sbin/iptables -t nat -D POSTROUTING -s $ip4.0/24 -o $gw -j MASQUERADE
+EOF
+if [[ $ip6net ]]; then
+ cat >>$f <<EOF
+ExecStartPre=/sbin/ip6tables -t nat -A POSTROUTING -s $ip6net -o $gw -j MASQUERADE
+ExecStopPost=/sbin/ip6tables -t nat -D POSTROUTING -s $ip6net -o $gw -j MASQUERADE
EOF
-systemctl daemon-reload # needed if the file was already there
-systemctl enable mynat.service
-systemctl start mynat.service
+ systemctl daemon-reload # needed if the file was already there
-systemctl restart openvpn@server
+ if $start; then
+ systemctl enable $vpn_service
+ systemctl restart $vpn_service
+ fi
+fi
iankelling.org / git / vpn-setup / blobdiff