TUN-857: Pull the brotli-go dependency from Github

vendor/github.com/coredns/coredns/plugin/normalize.go

@@ -125,8 +125,7 @@ func SplitHostPort(s string) (host, port string, ipnet *net.IPNet, err error) {
 			// Get the first lower octet boundary to see what encompassing zone we should be authoritative for.
 			mod := (bits - ones) % sizeDigit
 			nearest := (bits - ones) + mod
-			offset := 0
-			var end bool
+			offset, end := 0, false
 			for i := 0; i < nearest/sizeDigit; i++ {
 				offset, end = dns.NextLabel(rev, offset)
 				if end {

vendor/github.com/coredns/coredns/request/request.go

@@ -263,16 +263,12 @@ func (r *Request) Scrub(reply *dns.Msg) (*dns.Msg, Result) {
 
 	// Account for the OPT record that gets added in SizeAndDo(), subtract that length.
 	sub := 0
-	if r.Req.IsEdns0() != nil {
+	if r.Do() {
 		sub = optLen
 	}
-
-	// substract to make spaces for re-added EDNS0 OPT RR.
-	re := len(reply.Extra) - sub
-	size -= sub
-
-	l, m := 0, 0
 	origExtra := reply.Extra
+	re := len(reply.Extra) - sub
+	l, m := 0, 0
 	for l < re {
 		m = (l + re) / 2
 		reply.Extra = origExtra[:m]
@@ -301,9 +297,9 @@ func (r *Request) Scrub(reply *dns.Msg) (*dns.Msg, Result) {
 		return reply, ScrubExtra
 	}
 
+	origAnswer := reply.Answer
 	ra := len(reply.Answer)
 	l, m = 0, 0
-	origAnswer := reply.Answer
 	for l < ra {
 		m = (l + ra) / 2
 		reply.Answer = origAnswer[:m]
@@ -328,12 +324,14 @@ func (r *Request) Scrub(reply *dns.Msg) (*dns.Msg, Result) {
 		// this extra m-1 step does make it fit in the client's buffer however.
 	}
 
-	r.SizeAndDo(reply)
+	// It now fits, but Truncated. We can't call sizeAndDo() because that adds a new record (OPT)
+	// in the additional section.
 	reply.Truncated = true
 	return reply, ScrubAnswer
 }
 
-// Type returns the type of the question as a string. If the request is malformed the empty string is returned.
+// Type returns the type of the question as a string. If the request is malformed
+// the empty string is returned.
 func (r *Request) Type() string {
 	if r.Req == nil {
 		return ""