Add another example: chaos

Show the version and hostname.bind

examples/Makefile

@@ -2,8 +2,11 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
-all: mx
+all: mx chaos
 
 # too lazy to lookup how this works again in Makefiles
 mx: mx.go
 	6g -I ../_obj mx.go && 6l -L ../_obj -o mx mx.6
+
+chaos: chaos.go
+	6g -I ../_obj chaos.go && 6l -L ../_obj -o chaos chaos.6

examples/chaos.go

@@ -0,0 +1,71 @@
+package main
+
+// Print the version.bind and hostname.bind for each
+// address of NAMESERVER
+import (
+	"dns"
+        "os"
+        "fmt"
+        "net"
+)
+
+func main() {
+	r := new(dns.Resolver)
+	qr := dns.NewQuerier(r)
+        r.Servers = []string{"127.0.0.1"}
+        r.Timeout = 2
+        r.Attempts = 1
+
+        if len(os.Args) != 2 {
+                fmt.Printf("%s NAMESERVER\n", os.Args[0])
+                os.Exit(1)
+        }
+
+        m := new(dns.Msg)
+        m.Question = make([]dns.Question, 1)
+        for _, a := range addresses(qr, os.Args[0]) {
+                // set the resolver to query the NS directly
+                r.Servers = []string{a.String()}
+                m.Question[0] = dns.Question{"version.bind.", dns.TypeTXT, dns.ClassCHAOS}
+                qr <- dns.DnsMsg{m, nil}
+                in := <-qr
+                if in.Dns != nil && in.Dns.Answer != nil {
+                        fmt.Printf("%v\n", in.Dns.Answer[0])
+                }
+        }
+
+        // Stop the resolver, send it a null mesg
+        qr <- dns.DnsMsg{nil, nil}
+        <-qr
+}
+
+func addresses(qr chan dns.DnsMsg, name string) []net.IP {
+        m := new(dns.Msg)
+        m.MsgHdr.Recursion_desired = true //only set this bit
+        m.Question = make([]dns.Question, 1)
+        var ips []net.IP
+
+        m.Question[0] = dns.Question{os.Args[1], dns.TypeA, dns.ClassINET}
+        qr <- dns.DnsMsg{m, nil}
+        in := <-qr
+
+        if in.Dns.Rcode != dns.RcodeSuccess {
+                return nil
+        }
+        // Stuff must be in the answer section
+        for _, a := range in.Dns.Answer {
+                ips = append(ips, a.(*dns.RR_A).A)
+        }
+        m.Question[0] = dns.Question{os.Args[1], dns.TypeAAAA, dns.ClassINET}
+        qr <- dns.DnsMsg{m, nil}
+        in = <-qr
+
+        if in.Dns.Rcode != dns.RcodeSuccess {
+                return nil
+        }
+        // Stuff must be in the answer section
+        for _, a := range in.Dns.Answer {
+                ips = append(ips, a.(*dns.RR_AAAA).AAAA)
+        }
+        return ips
+}