Fix more robust, but also nack more about non qualified names

ex/q/q.go

@@ -114,7 +114,7 @@ Flags:
 		qtype = dns.TypeA
 	}
 
-	nameserver = string([]byte(nameserver)[1:]) // chop off @
+	nameserver = dns.Fqdn(string([]byte(nameserver)[1:])) // chop off @
 	nameserver += ":" + strconv.Itoa(*port)
 
 	// We use the async query handling, just to show how it is to be used.
@@ -180,7 +180,7 @@ Flags:
 	}
 
 	for i, v := range qname {
-		m.Question[0] = dns.Question{v, qtype, qclass}
+		m.Question[0] = dns.Question{dns.Fqdn(v), qtype, qclass}
 		m.Id = dns.Id()
 		if *query {
 			fmt.Printf("%s", m.String())
@@ -203,7 +203,8 @@ Flags:
 				}
 			}()
 		Redo:
-			if r == nil {
+			if e != nil {
+				fmt.Printf(";; %s\n", e.Error())
 				return
 			}
 			if r.Rcode != dns.RcodeSuccess {

msg.go

@@ -1077,7 +1077,9 @@ func PackRR(rr RR, msg []byte, off int, compression map[string]int, compress boo
 	if !ok {
 		return len(msg), false
 	}
-	rawSetRdlength(msg, off, off1)
+	if !rawSetRdlength(msg, off, off1) {
+		return len(msg), false
+	}
 	return off1, true
 }
 

rawmsg.go

@@ -7,6 +7,8 @@ package dns
 // These raw* functions do not use reflection, they directly set the values
 // in the buffer. There are faster than their reflection counterparts.
 
+// TODO: make them all return booleans
+
 // RawSetId sets the message id in buf.
 func rawSetId(msg []byte, i uint16) {
 	msg[0], msg[1] = packUint16(i)
@@ -35,10 +37,14 @@ func rawSetExtraLen(msg []byte, i uint16) {
 // rawSetRdlength sets the rdlength in the header of
 // the RR. The offset 'off' must be positioned at the
 // start of the header of the RR, 'end' must be the
-// end of the RR. There is no check if we overrun the buffer.
-func rawSetRdlength(msg []byte, off, end int) {
+// end of the RR.
+func rawSetRdlength(msg []byte, off, end int) bool {
+	l := len(msg)
 Loop:
 	for {
+		if off+1 > l {
+			return false
+		}
 		c := int(msg[off])
 		off++
 		switch c & 0xC0 {
@@ -57,8 +63,11 @@ Loop:
 	// The domainname has been seen, we at the start of the fixed part in the header.
 	// Type is 2 bytes, class is 2 bytes, ttl 4 and then 2 bytes for the length.
 	off += 2 + 2 + 4
+	if off+2 > l {
+		return false
+	}
 	//off+1 is the end of the header, 'end' is the end of the rr
 	//so 'end' - 'off+2' is the lenght of the rdata
 	msg[off], msg[off+1] = packUint16(uint16(end - (off + 2)))
-	return
+	return true
 }