旁路断网自动切换

16 June 2023   399 words   ~1 min
#Homelab

Table of Contents

前

因为家里使用旁陆游的方式来进行部署，有时候折腾会导致断网和不稳定的情况，为了让家庭网络可以自断网之后快速恢复。

就想了一个方法，使用脚本在路由上运行进行ping test，出现问题则调用系统配置进行网关切换。

注：此文已经过期，有更优秀的Keepalive方式，链接

正文

部署下面的脚本在 华硕路由器上，定期去检查旁路由是否可用，不可用则使用系统api来进行默认网关变更。

#!/bin/bash

default_gateway='192.168.0.4'
auxiliary_gateway='192.168.0.1'

# Use 8.8.8.8
up_gateway='8.8.8.8'
pkt_num=3
check_ip_available(){
    ping -c $pkt_num $1 | grep packets | awk '{print $4}'
}

# If the gateway of the up close, the network is completely unusable

res=`check_ip_available $up_gateway`
echo $res
if [ $((res)) -eq 0 ]; then
  echo "up_gateway unusable"
  exit 1
fi


cur_gateway=`/bin/nvram get dhcp_gateway_x` # get current gateway

if [ "$cur_gateway" = "$default_gateway" ]; then
   echo "cur is default_gateway"
   res=`check_ip_available $auxiliary_gateway`
   if [ $(($res)) -eq 0 ]; then
      echo "auxiliary_gateway not avaliable, abort"
      exit 1
   fi
   
   res=`check_ip_available $cur_gateway`
   if [ $(($res)) -eq $pkt_num ]; then
      echo "default_gateway works fine, skip"
      exit 1
   fi
 
   echo "switch to auxiliary"
   # to switch
   /bin/nvram set dhcp_gateway_x=$auxiliary_gateway
   /bin/nvram set dhcp_dns1_x=$auxiliary_gateway
   /bin/nvram set dhcp_dns2_x=""
   /bin/nvram commit

   /sbin/rc rc_service restart_net_and_phy
   exit 0
fi


if [ "$cur_gateway" = "$auxiliary_gateway" ]; then
   echo "cur is auxiliary_gateway"
   res=`check_ip_available $auxiliary_gateway`
   if [ $(($res)) -eq 0 ]; then
      echo "auxiliary_gateway not avaliable, abort"
      exit 1
   fi
   
   res=`check_ip_available $default_gateway`
   if [ $(($res)) -eq 0 ]; then
      echo "default_gateway still not works, skip"
      exit 1
   fi
   
   echo "default_gateway works fine now"
   echo "switch to default"
   # to switch
   /bin/nvram set dhcp_gateway_x=$default_gateway
   /bin/nvram set dhcp_dns1_x=$default_gateway
   /bin/nvram set dhcp_dns2_x=$auxiliary_gateway
   /bin/nvram commit
   
   /sbin/rc rc_service restart_net_and_phy
   exit 0
fi

echo "nothing change"

参考

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