Auto connect to PKU Gateway & send IP Address to ServerChan

check-server-status.sh

#!/bin/bash

###############################################################################
# To Run this script hourly, you need to add the following cron job:
# crontab -e
#
# Add the following line:
# 0 * * * * /path/to/check-server-status.sh
#
# Then save and exit.
###############################################################################

### SECRETS ###
# Serverchan sendkey https://sct.ftqq.com/
SCKEY='SCTxxxxxxxxxxxxxxxxxxxxxxxxx'
# SSH Target
SSH_TARGET='random@guy.im'

# Credit: https://stackoverflow.com/questions/296536/
rawurlencode() {
  local string="${1}"
  local strlen=${#string}
  local encoded=""
  local pos c o

  for (( pos=0 ; pos<strlen ; pos++ )); do
     c=${string:$pos:1}
     case "$c" in
        [-_.~a-zA-Z0-9] ) o="${c}" ;;
        * )               printf -v o '%%%02x' "'$c"
     esac
     encoded+="${o}"
  done
  echo "${encoded}"    # You can either set a return variable (FASTER)
  REPLY="${encoded}"   #+or echo the result (EASIER)... or both... :p
}

send_sc_message() {
    if [ -z "$SCKEY" ]; then
        # time
        echo "SCKEY not set"
        return 1
    fi

    if [ -z "$1" ]; then
        # time
        echo "No message to send"
        return 1
    fi

    curl -s -X POST -H 'Content-Type: application/x-www-form-urlencoded' \
        -d "title=$(rawurlencode "$1")&desp=$(rawurlencode "$2")" \
        "https://sc.ftqq.com/$SCKEY.send"
}

# main routine

ssh -q -o BatchMode=yes  -o StrictHostKeyChecking=no -o ConnectTimeout=5 "$SSH_TARGET" 'exit 0'
if [ $? -ne 0 ]; then
      # time
      echo "Lost Connection to $SSH_TARGET"
      send_sc_message "$SSH_TARGET is down" "$SSH_TARGET is down"
      echo ""
  else
      echo "Connected to $SSH_TARGET"
      exit 0
  fi

pku-auto-connect.sh

#!/bin/sh
###############################################################################
# To Run this script hourly, you need to add the following cron job:
# crontab -e
#
# Add the following line:
# 0 * * * * /path/to/pku-auto-connect.sh
#
# Then save and exit.
###############################################################################

### SECRETS ###
# Serverchan sendkey https://sct.ftqq.com/
SCKEY='SCTxxxxxxxxxxxxxxxxxxxxxxxx'
# UserName and Password of PKU IGSW
CONNECT_USER='1800000000'
CONNECT_PASSWORD='PKUIGSWPASSWORD'

### CONFIG ###
ALWAYS_ONLINE_SITES='http://www.baidu.com http://www.taobao.com'
ALWAYS_ONLINE_SITES_V6='http://byr.pt'
# CONNECT_PATH='./connect'
CONNECT_URL="https://its4.pku.edu.cn/cas/ITSClient"

# New API Interface
connect() {
  CONNECT_ARGS="cmd=open&username=${CONNECT_USER}&password=${CONNECT_PASSWORD}&iprange=free"
  curl -Gs -X POST --connect-timeout 5 -d $CONNECT_ARGS  "$CONNECT_URL"
}

send_sc_message() {
    if [ -z "$1" ] || [ -z "$2" ]; then
        echo "Missing message or title: message=$1 title=$2"
        return 1
    fi
    curl -Gs "https://sc.ftqq.com/$SCKEY.send" \
        -X POST \
        -H 'Content-Type: application/x-www-form-urlencoded' \
        --data-urlencode "$(printf 'title=%s' "$1")" \
        --data-urlencode "$(printf 'desp=%s' "$2")"
}

# main routine

SC_TITLE=""
SC_BODY=""

# test whether we are online
for site in $ALWAYS_ONLINE_SITES; do
    echo "Checking link to $site"
    # if redirected to login page, then we are not online
    curl --connect-timeout 5 -s -o /dev/null -I -w "%{http_code}" "$site" | grep -q 302
    if [ $? -eq 0 ]; then
        # time
        echo " Link lost, try reconnecting..."
        connect
        if [ $? -ne 0 ]; then
            # time
            echo "Error: reconnect failed"
            exit 1
        else
            # get_ip
            # printf '%-12s %s\n'  gateway $gateway iface $iface ip $ip
            ip=$(ip route get 1 | awk '{print $(NF-2);exit}')
            gateway=$(ip route get 1 | awk '{print $3;exit}')
            iface=$(ip route get 1 | awk '{print $5;exit}')
            SC_TITLE="Reconnected: $ip"
            SC_BODY="[IPv4] Gateway: $gateway, Interface: $iface, IP: $ip"
        fi
    elif [ -z "$SC_TITLE" ]; then
        echo " Link established"
        break
    fi
done

# check IPv6
for site in $ALWAYS_ONLINE_SITES_V6; do
    echo "Checking link to $site"
    # if redirected to login page, then we are not online
    curl --connect-timeout 5 -s -o /dev/null -I -w "%{http_code}" "$site"
    if [ $? -eq 0 ]; then
        # get_ip
        # printf '%-12s %s\n'  gateway $gateway iface $iface ip $ip
        ip=$(ip route get 2001:da8::666 | awk '{print $(NF-4);exit}')
        gateway=$(ip route get 2001:da8::666 | awk '{print $5;exit}')
        iface=$(ip route get 2001:da8::666 | awk '{print $7;exit}')
        SC_BODY="${SC_BODY} [IPv6] Gateway: $gateway, Interface: $iface, IP: $ip"
        break
    else
        # do a curl -v
        SC_BODY="${SC_BODY} [IPv6] $(curl -v --connect-timeout 5 $site)"
        break
    fi
done

if [[ ! -z "$SC_TITLE" ]]; then
    send_sc_message "$SC_TITLE" "$SC_BODY"
    echo ""
fi