func multidns(query *dns.Msg, out chan *dns.Msg) {
start := time.Now()
response := make(chan dnsresponse, len(servers))
for _, server := range servers {
go singlequery(query, server, response)
//var req dnsrequest
//req.query.response = query
//req.query.server = server
//req.channel = response
//service <- req
}
var logline string
sent := false
var allresults []*dns.Msg
for i := 0; i < len(servers); i++ {
result := <-response
if !sent && result.response != nil {
//We have a winner...
//Send only one response. query is satisfied. now dick around to collect more stats
out <- result.response
sent = true
//Log with special flag. May not always be the first to answer...
logline += fmt.Sprintf("%s (%s - W) ; ", result.server, time.Since(start))
} else {
//... but log everyone
logline += fmt.Sprintf("%s (%s) ; ", result.server, time.Since(start))
}
//extract ips from result.response
if result.response != nil {
if iscachable(result.response) {
for _, ans := range result.response.Answer {
if ans.Header().Rrtype == dns.TypeA {
//fmt.Printf("%s\n", ans.(*dns.A).A)
ipchan <- fmt.Sprintf("%s", ans.(*dns.A).A)
}
}
allresults = append(allresults, result.response)
}
}
}
//logline += "\n"
var name []string
for _, q := range query.Question {
name = append(name, q.Name+":"+dns.Class(q.Qclass).String())
}
fmt.Printf("%s (%s): %s\n", start, name, logline)
if len(allresults) > 0 {
putincache(allresults)
}
//fmt.Printf("Exiting...\n")
}
// ServeDNS is the entry point for every request to the address that s
// is bound to. It acts as a multiplexer for the requests zonename as
// defined in the request so that the correct zone
// (configuration and middleware stack) will handle the request.
func (s *Server) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
defer func() {
// In case the user doesn't enable error middleware, we still
// need to make sure that we stay alive up here
if rec := recover(); rec != nil {
DefaultErrorFunc(w, r, dns.RcodeServerFailure)
}
}()
if m, err := middleware.Edns0Version(r); err != nil { // Wrong EDNS version, return at once.
rc := middleware.RcodeToString(dns.RcodeBadVers)
state := middleware.State{W: w, Req: r}
metrics.Report(state, metrics.Dropped, rc, m.Len(), time.Now())
w.WriteMsg(m)
return
}
// Execute the optional request callback if it exists
if s.ReqCallback != nil && s.ReqCallback(w, r) {
return
}
q := r.Question[0].Name
b := make([]byte, len(q))
off, end := 0, false
ctx := context.Background()
for {
l := len(q[off:])
for i := 0; i < l; i++ {
b[i] = q[off+i]
// normalize the name for the lookup
if b[i] >= 'A' && b[i] <= 'Z' {
b[i] |= ('a' - 'A')
}
}
if h, ok := s.zones[string(b[:l])]; ok {
if r.Question[0].Qtype != dns.TypeDS {
rcode, _ := h.stack.ServeDNS(ctx, w, r)
if RcodeNoClientWrite(rcode) {
DefaultErrorFunc(w, r, rcode)
}
return
}
}
off, end = dns.NextLabel(q, off)
if end {
break
}
}
// Wildcard match, if we have found nothing try the root zone as a last resort.
if h, ok := s.zones["."]; ok {
rcode, _ := h.stack.ServeDNS(ctx, w, r)
if RcodeNoClientWrite(rcode) {
DefaultErrorFunc(w, r, rcode)
}
return
}
// Still here? Error out with REFUSED and some logging
remoteHost := w.RemoteAddr().String()
DefaultErrorFunc(w, r, dns.RcodeRefused)
log.Printf("[INFO] \"%s %s %s\" - No such zone at %s (Remote: %s)", dns.Type(r.Question[0].Qtype), dns.Class(r.Question[0].Qclass), q, s.Addr, remoteHost)
}
// Class returns the class of the question in the request.
func (s *State) Class() string { return dns.Class(s.Req.Question[0].Qclass).String() }
func questionToString(q dns.Question) string {
return fmt.Sprintf("%s %s %s", q.Name, dns.Class(q.Qclass), dns.Type(q.Qtype))
}
func textConvertMessage(m *Message, s *bytes.Buffer) {
isQuery := false
printQueryAddress := false
switch *m.Type {
case Message_CLIENT_QUERY,
Message_RESOLVER_QUERY,
Message_AUTH_QUERY,
Message_FORWARDER_QUERY,
Message_TOOL_QUERY:
isQuery = true
case Message_CLIENT_RESPONSE,
Message_RESOLVER_RESPONSE,
Message_AUTH_RESPONSE,
Message_FORWARDER_RESPONSE,
Message_TOOL_RESPONSE:
isQuery = false
default:
s.WriteString("[unhandled Message.Type]\n")
return
}
if isQuery {
textConvertTime(s, m.QueryTimeSec, m.QueryTimeNsec)
} else {
textConvertTime(s, m.ResponseTimeSec, m.ResponseTimeNsec)
}
s.WriteString(" ")
switch *m.Type {
case Message_CLIENT_QUERY,
Message_CLIENT_RESPONSE:
{
s.WriteString("C")
}
case Message_RESOLVER_QUERY,
Message_RESOLVER_RESPONSE:
{
s.WriteString("R")
}
case Message_AUTH_QUERY,
Message_AUTH_RESPONSE:
{
s.WriteString("A")
}
case Message_FORWARDER_QUERY,
Message_FORWARDER_RESPONSE:
{
s.WriteString("F")
}
case Message_STUB_QUERY,
Message_STUB_RESPONSE:
{
s.WriteString("S")
}
case Message_TOOL_QUERY,
Message_TOOL_RESPONSE:
{
s.WriteString("T")
}
}
if isQuery {
s.WriteString("Q ")
} else {
s.WriteString("R ")
}
switch *m.Type {
case Message_CLIENT_QUERY,
Message_CLIENT_RESPONSE,
Message_AUTH_QUERY,
Message_AUTH_RESPONSE:
printQueryAddress = true
}
if printQueryAddress {
textConvertIP(s, m.QueryAddress)
} else {
textConvertIP(s, m.ResponseAddress)
}
s.WriteString(" ")
if m.SocketProtocol != nil {
s.WriteString(m.SocketProtocol.String())
}
s.WriteString(" ")
var err error
msg := new(dns.Msg)
if isQuery {
s.WriteString(strconv.Itoa(len(m.QueryMessage)))
s.WriteString("b ")
err = msg.Unpack(m.QueryMessage)
} else {
s.WriteString(strconv.Itoa(len(m.ResponseMessage)))
s.WriteString("b ")
err = msg.Unpack(m.ResponseMessage)
}
if err != nil {
s.WriteString("X ")
} else {
s.WriteString("\"" + msg.Question[0].Name + "\" ")
s.WriteString(dns.Class(msg.Question[0].Qclass).String() + " ")
s.WriteString(dns.Type(msg.Question[0].Qtype).String())
}
s.WriteString("\n")
}
