ab26a1333b733eaba7e5307d70df3ed1f18cbce4
2 # Copyright (C) 2016 Ian Kelling
4 # Licensed under the Apache License, Version 2.0 (the "License");
5 # you may not use this file except in compliance with the License.
6 # You may obtain a copy of the License at
8 # http://www.apache.org/licenses/LICENSE-2.0
10 # Unless required by applicable law or agreed to in writing, software
11 # distributed under the License is distributed on an "AS IS" BASIS,
12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 # See the License for the specific language governing permissions and
14 # limitations under the License.
16 [[ $EUID == 0 ]] ||
exec sudo
"$BASH_SOURCE" "$@"
18 source /a
/bin
/errhandle
/errcatch-function
19 source /a
/bin
/errhandle
/errallow-function
20 source /a
/bin
/errhandle
/bash-trace-function
25 Usage: mail-route start|stop|show
27 Marks tcp packets on port 25 and 143 to be routed through
33 if (( $# != 1 )); then
42 # systemd around stretch release time, would wait until openvpn actually connected,
43 # so this was unnecessary, but now it returns immediately.
45 for ((i
=1; i
<=30; i
++)); do
46 tun_dev
=$
(ip a show to
10.8.0.4/24 |
sed -rn '1s/^\S+\s+([^:]+).*/\1/p')
47 if [[ $tun_dev == tun
* ]]; then
54 echo "$0: error: timeout waiting for valid tun_dev, currently:$tun_dev"
57 e
() { echo "$0: $*"; "$@"; }
58 _errcatch_cleanup
=stop
60 # we leave it as is even when stopping, because we would like it to be default, but the only way
61 # to change the default is for every device, and I want to avoid that, even though I wouldn't mind, others users of this script might.
62 e sysctl net.ipv4.conf.
$tun_dev.rp_filter
=2
69 tun_dev
=$
(ip a show to
10.8.0.4/24 |
sed -rn '1s/^\S+\s+([^:]+).*/\1/p')
70 e
() { echo "$0: $*"; "$@" ||
printf "maybe ok failure: %s\n" "$*"; }
75 e
() { printf "${0##*/}: %s\n" "$*"; "$@"; }
76 e iptables
-t mangle
-S
79 e ip route show table
1
81 tun_dev
=$
(ip a show to
10.8.0.4/24 |
sed -rn '1s/^\S+\s+([^:]+).*/\1/p')
82 if [[ $tun_dev == tun
* ]]; then
83 e sysctl net.ipv4.conf.
$tun_dev.rp_filter
85 echo "$0: note, no tun device found"
92 #echo start=$start stop=$stop exists=$exists
93 { $start && ! $exists; } ||
{ $stop && $exists; }
96 iptmod
() { #iptables modify
97 local check cmd
="$*" exists
=true
98 ${cmd/-[AD]/-C} &>/dev
/null || exists
=false
99 if runtest
; then e
$cmd; fi
102 # code common to start and stop.
104 # match source or dest port. note, when we send to a port, it picks a random high port as
106 for port
in 25 143; do # smtp and imap.
107 iptcommon
="OUTPUT -m tcp -p tcp -m multiport --ports $port -j MARK --set-mark"
108 iptmod iptables
-t mangle
$iptables_op $iptcommon 0x1
109 iptmod iptables
-t mangle
$iptables_op $iptcommon 0x0 -d 10.0.0.0/8,172.16.0.0/12,192.168.0.0/16
110 # note, we could have used a custom chain and returned instead of setting the mark again.
111 # in case anyone was ever curious, the inverse of private ips is: #0.0.0.0/5,8.0.0.0/7,11.0.0.0/8,12.0.0.0/6,16.0.0.0/4,32.0.0.0/3,64.0.0.0/2,128.0.0.0/3,160.0.0.0/5,168.0.0.0/6,172.0.0.0/12,172.32.0.0/11,172.64.0.0/10,172.128.0.0/9,173.0.0.0/8,174.0.0.0/7,176.0.0.0/4,192.0.0.0/9,192.128.0.0/11,192.160.0.0/13,192.169.0.0/16,192.170.0.0/15,192.172.0.0/14,192.176.0.0/12,192.192.0.0/10,193.0.0.0/8,194.0.0.0/7,196.0.0.0/6,200.0.0.0/5,208.0.0.0/4,224.0.0.0/3
114 if [[ $tun_dev ]]; then
115 # when $tun_dev goes away, so does this rul
116 iptmod iptables
-t nat
$iptables_op POSTROUTING
-o $tun_dev -m mark
--mark 0x1 -j SNAT
--to-source 10.8.0.4
120 iprulecmd
="fwmark 1 table 1"
121 exists
=true
; ip rule show
$iprulecmd |
grep .
&>/dev
/null || exists
=false
122 if runtest
; then e ip rule
$ip_op $iprulecmd; fi
124 iproutecmd
="default via 10.8.0.1 table 1"
125 exists
=true
; ip route show
$iproutecmd |
grep .
&>/dev
/null || exists
=false
126 if runtest
; then e ip route
$ip_op $iproutecmd; fi
128 # on debian this is 0 (no filter), on ubuntu it\'s 1, which is no good. 0 or 2 both work fine.
129 # 2 drops it if the packet is not routable, martian address, or my default route is screwed up,
130 # so, eh, might as well. some rhel docs recommend using it.
137 start|stop|show
) $1 ;;
142 # background: something like this does not work for packets which
143 # exim is replying to. I don't know why.
144 #iptables -t mangle -A OUTPUT -m owner --uid-owner Debian-exim -j MARK --set-mark 0x1