95 lines
3.0 KiB
Go
95 lines
3.0 KiB
Go
/*
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crondyn, a cron-compatible dynamic DNS update utility.
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© 2014 Ken Piper <kealper@gmail.com>
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This file is part of crondyn.
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crondyn is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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crondyn is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with crondyn. If not, see <http://www.gnu.org/licenses/>.
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*/
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package main
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import (
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"fmt"
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"encoding/json"
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"net/http"
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"net/url"
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"io/ioutil"
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"runtime"
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)
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type Config struct {
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Username string
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Password string
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Hostname string
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DNSServer string
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}
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func shutDown() {
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if panicReason := recover(); panicReason != nil {
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fmt.Println("Program has encountered an unrecoverable error and has crashed.")
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fmt.Println("Some information describing this crash: "+panicReason.(error).Error())
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fmt.Println("Crash reporting is enabled, collecting stack trace and submitting crash report...")
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stack := make([]byte, 8192)
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l := runtime.Stack(stack, true)
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resp, err := http.PostForm("http://stacktrace.kealper.com/api.a3w", url.Values{"agent": {"crondns/1.0"}, "crash": {panicReason.(error).Error()}, "stack": {string(stack[:l])}})
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if err != nil {
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fmt.Println("Failed to submit crash report, closing.")
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} else {
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resp.Body.Close()
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fmt.Println("Crash report submitted, closing.")
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}
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}
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}
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func main() {
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defer shutDown()
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configFile, _ := ioutil.ReadFile("config.json")
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config := new(Config)
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err := json.Unmarshal(configFile, config)
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if err != nil {
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fmt.Println("Failed to load configuration! Closing...")
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return
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}
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lastIP, err := ioutil.ReadFile("lastip")
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if err != nil {
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lastIP = []byte("0.0.0.0")
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}
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resp, err := http.Get("http://"+config.DNSServer+"/checkip.php")
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if err != nil {
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resp, err = http.Get("http://kealper.com/ip")
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if err != nil {
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fmt.Println("Failed to get current IP address! Closing...")
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return
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}
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}
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currentIP, _ := ioutil.ReadAll(resp.Body)
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resp.Body.Close()
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if string(currentIP) != string(lastIP) {
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fmt.Println("Found updated IP address:", string(currentIP))
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if err := ioutil.WriteFile("lastip", currentIP, 0644); err != nil {
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fmt.Println("Failed to save the current IP to the disk! Permissions issue?")
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}
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_, err := http.Get("http://"+config.Username+":"+config.Password+"@"+config.DNSServer+"/dynamicupdate.php?ip="+string(currentIP)+"&hostname="+config.Hostname)
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if err != nil {
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fmt.Println("Failed to update hostname:", config.Hostname)
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return
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} else {
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fmt.Println("Hostname", config.Hostname, "updated successfully.")
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}
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} else {
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fmt.Println("No IP address change since last check.")
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}
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}
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