X-Git-Url: https://iankelling.org/git/?p=vpn-setup;a=blobdiff_plain;f=vpn-server-setup;h=c135d4e862cb524b041977018e9cbc377f0bbcf0;hp=ded2a785f59250b265f2307a85ccdb3e04cfb98c;hb=HEAD;hpb=50a29b33506900a8bc5d87e67ea0d3fd9bd69369

diff --git a/vpn-server-setup b/vpn-server-setup
index ded2a78..c135d4e 100755
--- a/vpn-server-setup
+++ b/vpn-server-setup
@@ -1,5 +1,12 @@
-#!/bin/bash -x
-# Copyright (C) 2016 Ian Kelling
+#!/bin/bash
+# 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.
@@ -21,20 +28,34 @@ trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR
 
 usage() {
   cat <<'EOF'
-usage: ${0##*/} [-d|-h|--help]
-
--r  Do not push default route
--d  Do not push dns
--s  Do not start openvpn
+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.
 
-You can save all the keys by storing /etc/openvpn/easy-rsa/keys, and
+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
+
 Note: Uses GNU getopt options parsing style
 EOF
   exit $1
@@ -43,11 +64,18 @@ EOF
 dns=true
 route=true
 start=true
-temp=$(getopt -l help drsh "$@") || usage 1
+ip4=10.8.0
+name=server
+temp=$(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 ;;
@@ -56,25 +84,20 @@ while true; do
   esac
 done
 
-apt-get update
-# suggests get's us openssl. policy-rc.d is to prevent install from starting services
-f=/usr/sbin/policy-rc.d;
-dd of=$f <<EOF
-#!/bin/sh
-exit 101
-EOF
-chmod +x $f;
-apt-get install --install-suggests -y openvpn
-rm $f
+read -r ip6 ip6route <<<"$@"
+
+source /a/bin/distro-functions/src/package-manager-abstractions
+
+pi-nostart openvpn openssl easy-rsa uuid-runtime
 
 if [[ -e /lib/systemd/system/openvpn-server@.service ]]; then
-  vpn_service=openvpn-server@server
+  vpn_service=openvpn-server@$name
 else
-  vpn_service=openvpn@server
+  vpn_service=openvpn@$name
 fi
-apt-get install -y uuid-runtime easy-rsa
-mkdir -p /etc/openvpn/easy-rsa
-cd /etc/openvpn/easy-rsa
+rsadir=/etc/openvpn/easy-rsa-$name
+mkdir -p $rsadir
+cd $rsadir
 cp -r /usr/share/easy-rsa/* .
 if [[ -e openssl-1.0.0.cnf && ! -e openssl.cnf ]]; then
   # there's a debian bug about this.
@@ -84,13 +107,22 @@ fi
 server_dir=/etc/openvpn/server
 mkdir -p $server_dir
 chmod 700 $server_dir
+conf=$server_dir/$name.conf
 
 
 new=true
-keyfiles=(/etc/openvpn/easy-rsa/pki/{ca.crt,private/server.key,issued/server.crt})
+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
-  keyfiles=(/etc/openvpn/easy-rsa/keys/{ca.crt,server.{crt,key}})
+  ca_origin=$rsadir/ca.crt
+  keyfiles=(
+    $rsadir/keys/$name.key
+    $rsadir/keys/$name.crt
+  )
 fi
 
 keys_exist=true
@@ -101,14 +133,24 @@ for f in ${keyfiles[@]}; do
   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
-  openvpn --genkey --secret $server_dir/ta.key
   if $new; then
+    echo 'set_var EASYRSA_NS_SUPPORT      "yes"' >vars
     ./easyrsa init-pki
     ./easyrsa --batch build-ca nopass
-    ./easyrsa build-server-full server nopass
-    openssl dhparam -out $server_dir/dh2048.pem 2048
+    ./easyrsa --days=3650 build-server-full $name nopass
   else
     # dun care about settning cert cn etc from the non-example values
     source vars
@@ -122,23 +164,27 @@ if ! $keys_exist; then
     # '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
+    { 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
 
-cp /usr/share/doc/openvpn/examples/sample-config-files/server.conf.gz $server_dir
-gzip -df $server_dir/server.conf.gz
-
-
+cafile=$server_dir/ca-$name.crt
+cp $ca_origin $cafile
 cp ${keyfiles[@]} $server_dir
 # for legacy systems
-for f in ${keyfiles[@]}; do
+for f in ${keyfiles[@]} $cafile; do
   ln -sf server/${f##*/} /etc/openvpn
 done
 
-cat >>$server_dir/server.conf <<'EOF'
+cat >>$conf <<EOF
 
 # I cat an extra blank line to start because the example config does
 # not have a final newline. ....
@@ -153,72 +199,106 @@ cipher AES-256-CBC
 client-config-dir /etc/openvpn/client-config
 
 # duplicate in newer sample configs
-tls-auth ta.key 0 # This file is secret
+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 10.8.0.1, there might be some other way, but stretch's
+# 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
-EOF
 
+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 - $server_dir/server.conf <<'EOF'
+sed -i --follow-symlinks -f - $conf <<'EOF'
 s/^dh dh1024.pem/dh dh2048.pem/
 /^comp-lzo.*/d
 EOF
 
 
-mkdir -p /etc/openvpn/client-config
-
-
 if $dns; then
   # Be the dns server for clients
-  cat >>$server_dir/server.conf <<'EOF'
-push "dhcp-option DNS 10.8.0.1"
+  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 $route; then
-  cat >>$server_dir/server.conf <<'EOF'
+  cat >>$conf <<'EOF'
 # Be the default gateway for clients.
 push "redirect-gateway def1"
 EOF
+  if [[ $ip6 ]]; then
+    cat >>$conf <<'EOF'
+push "route-ipv6 2000::/3"
+EOF
+  fi
 fi
+if [[ $port ]]; then
+  cat >>$conf <<EOF
+port $port
+EOF
+fi
+
 
 sed -i --follow-symlinks '/^ *net\.ipv4\.ip_forward=.*/d' /etc/sysctl.conf
-sed -i --follow-symlinks '/^ *net.ipv6.conf.all.forwarding=.*/d' /etc/sysctl.conf
 cat >>/etc/sysctl.conf <<'EOF'
 net.ipv4.ip_forward=1
-net.ipv6.conf.all.forwarding=1
 EOF
 sysctl -p /etc/sysctl.conf
 
-gw=$(ip route | sed -rn 's/^default via .* dev (\S+).*/\1/p')
-
-cat >/etc/systemd/system/vpnnat.service <<EOF
-[Unit]
-Description=Turns on nat iptables setting
+gw=$(ip route | sed -rn 's/^default via .* dev (\S+).*/\1/p' | head -n1)
 
+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 $gw -j MASQUERADE
-
-[Install]
-WantedBy=$vpn_service.service
+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
-systemctl daemon-reload # needed if the file was already there
-# note, no need to start it, the vpn_service does that.
-systemctl enable vpnnat
+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
 
-if $start; then
-  systemctl enable $vpn_service
-  systemctl restart $vpn_service
+  if $start; then
+    systemctl enable $vpn_service
+    systemctl restart $vpn_service
+  fi
 fi