Fixup for EDNS probe (neater than patch on mailing list).

git-svn-id: file:///svn/unbound/trunk@1684 be551aaa-1e26-0410-a405-d3ace91eadb9

doc/Changelog

@@ -1,3 +1,7 @@
+26 June 2009: Wouter
+	- Fix EDNS fallback when EDNS works for short answers but long answers
+	  are dropped.
+
 22 June 2009: Wouter
 	- fixup iter priv strict aliasing while preserving size of sockaddr.
 	- iana portlist updated.  (one less port allocated, one more fraction

doc/requirements.txt

@@ -235,6 +235,9 @@ o EDNS fallback. Is done according to the EDNS RFC (and update draft-00).
   It minimizes the chances of a dropped query making a (DNSSEC) EDNS server
   falsely EDNS-nonsupporting, and thus DNSSEC-bogus, works well with 
   middleboxes, and can detect the occasional authority that drops EDNS.
+  For some boxes it is necessary to probe for every failing query, a
+  reassurance that the DNS server does EDNS does not mean that path can
+  take large DNS answers.
 
 o 0x20 backoff.
   The draft describes to back off to the next server, and go through all

services/outside_network.c

@@ -1234,7 +1234,8 @@ serviced_udp_send(struct serviced_query* sq, ldns_buffer* buff)
 		&edns_lame_known, &rtt))
 		return 0;
 	if(sq->status == serviced_initial) {
-		if(edns_lame_known == 0 && rtt > 5000) {
+		if((vs != -1 || edns_lame_known == 0) && 
+			rtt > 5000 && rtt < 10001) {
 			/* perform EDNS lame probe - check if server is
 			 * EDNS lame (EDNS queries to it are dropped) */
 			verbose(VERB_ALGO, "serviced query: send probe to see "