mirror of
https://github.com/miekg/dns.git
synced 2025-08-20 00:11:00 +02:00
73 lines
1.4 KiB
Go
73 lines
1.4 KiB
Go
/*
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* Funkensturm, a versatile DNS proxy
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* Miek Gieben <miek@miek.nl> (c) 2011
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* GPLv2
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*/
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package main
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import (
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"dns"
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"flag"
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"log"
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"os"
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)
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var (
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listen = flag.String("listen", "127.0.0.1:8053", "set the listener address")
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server = flag.String("server", "127.0.0.1:53", "remote server address(es), seperate with commas")
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verbose = flag.Bool("verbose", false, "be more verbose")
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)
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func serve(w dns.ResponseWriter, r *dns.Msg, c *Cache) {
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if p := c.Find(r); p != nil {
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dns.RawSetId(p, r.MsgHdr.Id)
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w.WriteBuf(p)
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return
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}
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// Cache miss
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client := new(dns.Client)
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if p, e := client.Exchange(r, *server); e == nil {
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if *verbose {
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log.Printf("fks-shield: cache miss")
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}
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// TODO(mg): If r has edns0 and p has not we create a mismatch here
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w.Write(p)
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c.Insert(p)
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return
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} else {
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log.Printf("fks-shield: failed to get answer " + e.Error())
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// w.Write(SERFVAIL)
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}
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}
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func listenAndServe(add, net string) {
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if err := dns.ListenAndServe(add, net, nil); err != nil {
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log.Fatal("fks-shield: failed to setup %s %s", net, add)
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}
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}
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func main() {
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flag.Usage = func() {
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flag.PrintDefaults()
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}
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flag.Parse()
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cache := NewCache()
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dns.HandleFunc(".", func(w dns.ResponseWriter, r *dns.Msg) { serve(w, r, cache) })
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go listenAndServe(*listen, "tcp")
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go listenAndServe(*listen, "udp")
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sig := make(chan os.Signal)
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forever:
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for {
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select {
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case <-sig:
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log.Printf("fks-shield: signal received, stopping")
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break forever
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}
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}
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}
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