mirror of
https://github.com/tonusoo/koduinternet-cpe
synced 2024-11-14 23:30:58 +02:00
115 lines
3.0 KiB
Bash
Executable File
115 lines
3.0 KiB
Bash
Executable File
#!/usr/bin/env bash
|
|
|
|
# Title : isp-switch
|
|
# Last modified date : 30.05.2023
|
|
# Author : Martin Tonusoo
|
|
# Description : Script pings anycast DNS servers IPv4 addresses
|
|
# using a primary connection(wan0; Telia fiber) and
|
|
# if none of those replies, then switches v4 default
|
|
# route to backup connection(wwan0; Telia mobile
|
|
# broadband). Once the primary connection restores,
|
|
# the v4 default route is switched back to primary
|
|
# connection.
|
|
# Options :
|
|
# Notes : "ignore_routes_with_linkdown" settings in
|
|
# /etc/sysctl.conf ensure that the route is
|
|
# instantly ignored if its link is down.
|
|
|
|
|
|
ping_check() {
|
|
|
|
ping_success=0
|
|
|
|
for ip in 1.1.1.1 8.8.8.8 9.9.9.9; do
|
|
# Even if one ping out of four succeeds, then
|
|
# the exit code is 0.
|
|
ping -I "$1" -W 1 -c 4 -q "$ip" &>/dev/null
|
|
ping_success=$(( ping_success + $? ))
|
|
done
|
|
|
|
if (( ping_success >= 3 )); then
|
|
# All 12 pings failed.
|
|
return 1
|
|
else
|
|
return 0
|
|
fi
|
|
}
|
|
|
|
|
|
read -r ip_regex << EOF
|
|
^((25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]?|0)\.){3}\
|
|
(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9][0-9]?|0)$
|
|
EOF
|
|
|
|
|
|
while true; do
|
|
|
|
sleep 1
|
|
|
|
read -r _ _ wan0_gw _ wan0_metric _ <<-EOF
|
|
$(ip -4 -o route show default dev wan0 2>/dev/null | grep -v " linkdown")
|
|
EOF
|
|
|
|
read -r _ _ wwan0_gw _ wwan0_metric _ <<-EOF
|
|
$(ip -4 -o route show default dev wwan0 2>/dev/null | grep -v " linkdown")
|
|
EOF
|
|
|
|
|
|
# There is no point to proceed if both or one of the default
|
|
# routes is missing. In addition, sanity check the next hop
|
|
# address.
|
|
if ! { [[ "$wan0_gw" =~ $ip_regex ]] || [[ "$wwan0_gw" =~ $ip_regex ]]; }; then
|
|
|
|
echo "No default route found."
|
|
continue
|
|
|
|
elif ! [[ "$wan0_gw" =~ $ip_regex ]]; then
|
|
|
|
echo "Primary default route via wan0 is missing."
|
|
continue
|
|
|
|
elif ! [[ "$wwan0_gw" =~ $ip_regex ]]; then
|
|
|
|
echo "Failover default route via wwan0 is missing."
|
|
continue
|
|
|
|
fi
|
|
|
|
|
|
# Default IPv4 route metric is 0.
|
|
if (( ${wan0_metric:-0} < ${wwan0_metric:-0} )); then
|
|
|
|
if ! ping_check wan0; then
|
|
|
|
# Ping check on primary connection failed.
|
|
echo "Switching to backup via $wwan0_gw dev wwan0"
|
|
|
|
ip -4 route flush default
|
|
ip -4 route add default via "$wwan0_gw" dev wwan0 metric 100
|
|
ip -4 route add default via "$wan0_gw" dev wan0 metric 200
|
|
fi
|
|
|
|
else
|
|
# Backup connection is in use. Check if it is possible
|
|
# to switch back to primary connection.
|
|
ip -4 route add default via "$wan0_gw" table 100
|
|
# Specifying the "priority" ensures that there are
|
|
# no duplicate rules created.
|
|
ip rule add oif wan0 lookup 100 priority 100
|
|
|
|
if ping_check wan0; then
|
|
|
|
# Ping check on primary connection succeeded.
|
|
echo "Switching to primary via $wan0_gw dev wan0"
|
|
|
|
ip -4 route flush default
|
|
ip -4 route add default via "$wan0_gw" dev wan0 metric 100
|
|
ip -4 route add default via "$wwan0_gw" dev wwan0 metric 200
|
|
fi
|
|
|
|
ip -4 route flush table 100
|
|
ip rule delete oif wan0 lookup 100 priority 100
|
|
|
|
fi
|
|
done
|