fi
start() {
+ start=true
+ stop=false
iptables_op=-A
ip_op=add
# systemd around stretch release time, would wait until openvpn actually connected,
echo "$0: error: timeout waiting for valid tun_dev, currently:$tun_dev"
exit 1
fi
- e() { "$@"; }
+ e() { echo "$0: $*"; "$@"; }
_errcatch_cleanup=stop
modify
+ # we leave it as is even when stopping, because we would like it to be default, but the only way
+ # 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.
+ e sysctl net.ipv4.conf.$tun_dev.rp_filter=2
}
stop() {
+ start=false
+ stop=true
iptables_op=-D
ip_op=del
- tun_dev=$(iptables -t nat -S | sed -rn "s/^-A POSTROUTING -o (tun[[:digit:]]+) -m mark --mark 0x1 -j SNAT --to-source 10.8.0.4$/\1/p"|head -n1) || printf "failed to find tun device.\n"
- e() { "$@" || printf "maybe ok failure: %s\n" "$*"; }
+ tun_dev=$(ip a show to 10.8.0.4/24 | sed -rn '1s/^\S+\s+([^:]+).*/\1/p')
+ e() { echo "$0: $*"; "$@" || printf "maybe ok failure: %s\n" "$*"; }
modify
}
exit 0
}
+runtest() {
+ # debugging:
+ #echo start=$start stop=$stop exists=$exists
+ { $start && ! $exists; } || { $stop && $exists; }
+}
+
+iptmod() { #iptables modify
+ local check cmd="$*" exists=true
+ ${cmd/-[AD]/-C} &>/dev/null || exists=false
+ if runtest; then e $cmd; fi
+}
# code common to start and stop.
modify() {
# match source or dest port. note, when we send to a port, it picks a random high port as
# the source.
for port in 25 143; do # smtp and imap.
- e iptables -t mangle $iptables_op \
- OUTPUT -m tcp -p tcp -m multiport --ports $port -j MARK --set-mark 0x1
- e iptables -t mangle $iptables_op \
- OUTPUT -m tcp -p tcp -m multiport --ports $port -j MARK --set-mark 0x0 \
- -d 10.0.0.0/8,172.16.0.0/12,192.168.0.0/16
+ iptcommon="OUTPUT -m tcp -p tcp -m multiport --ports $port -j MARK --set-mark"
+ iptmod iptables -t mangle $iptables_op $iptcommon 0x1
+ iptmod iptables -t mangle $iptables_op $iptcommon 0x0 -d 10.0.0.0/8,172.16.0.0/12,192.168.0.0/16
# note, we could have used a custom chain and returned instead of setting the mark again.
# 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
-
done
- e iptables -t nat $iptables_op POSTROUTING -o $tun_dev -m mark --mark 0x1 -j SNAT --to-source 10.8.0.4
- e ip rule $ip_op fwmark 1 table 1
- # note, this rule does not persist when the tun interface is deleted
- e ip route $ip_op default via 10.8.0.1 table 1
+
+ if [[ $tun_dev ]]; then
+ # when $tun_dev goes away, so does this rul
+ iptmod iptables -t nat $iptables_op POSTROUTING -o $tun_dev -m mark --mark 0x1 -j SNAT --to-source 10.8.0.4
+ fi
+
+
+ iprulecmd="fwmark 1 table 1"
+ exists=true; ip rule show $iprulecmd | grep . &>/dev/null || exists=false
+ if runtest; then e ip rule $ip_op $iprulecmd; fi
+
+ iproutecmd="default via 10.8.0.1 table 1"
+ exists=true; ip route show $iproutecmd | grep . &>/dev/null || exists=false
+ if runtest; then e ip route $ip_op $iproutecmd; fi
# on debian this is 0 (no filter), on ubuntu it\'s 1, which is no good. 0 or 2 both work fine.
# 2 drops it if the packet is not routable, martian address, or my default route is screwed up,
# so, eh, might as well. some rhel docs recommend using it.
- e sysctl net.ipv4.conf.$tun_dev.rp_filter=2
+
exit 0
}
iankelling.org / git / distro-setup / blobdiff