From: Wouter Wijngaards <wouter@nlnetlabs.nl>
Date: Thu, 15 Sep 2011 14:32:17 +0000 (+0000)
Subject: After UDP timeout EDNS1480 probe, stop fragmentation caused trouble.
X-Git-Tag: release-1.4.14rc1~75
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1af30c02fc33468bc386eeea9f945842b145c8de;p=thirdparty%2Funbound.git

After UDP timeout EDNS1480 probe, stop fragmentation caused trouble.


git-svn-id: file:///svn/unbound/trunk@2492 be551aaa-1e26-0410-a405-d3ace91eadb9
---

diff --git a/doc/Changelog b/doc/Changelog
index 02617d94e..d29bb4fcf 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -1,6 +1,7 @@
 15 September 2011: Wouter
 	- release 1.4.13.
 	- trunk contains 1.4.14 in development.
+	- Unbound probes at EDNS1480 if there an EDNS0 timeout.
 
 12 September 2011: Wouter
 	- Reverted dns EDNS backoff fix, it did not help and needs
diff --git a/services/outside_network.c b/services/outside_network.c
index 5397e8afb..b7bc5ff75 100644
--- a/services/outside_network.c
+++ b/services/outside_network.c
@@ -1280,7 +1280,19 @@ serviced_encode(struct serviced_query* sq, ldns_buffer* buff, int with_edns)
 		edns.edns_present = 1;
 		edns.ext_rcode = 0;
 		edns.edns_version = EDNS_ADVERTISED_VERSION;
-		edns.udp_size = EDNS_ADVERTISED_SIZE;
+		if(sq->status == serviced_query_UDP_EDNS_FRAG) {
+			if(addr_is_ip6(&sq->addr, sq->addrlen)) {
+				if(EDNS_FRAG_SIZE_IP6 < EDNS_ADVERTISED_SIZE)
+					edns.udp_size = EDNS_FRAG_SIZE_IP6;
+				else	edns.udp_size = EDNS_ADVERTISED_SIZE;
+			} else {
+				if(EDNS_FRAG_SIZE_IP4 < EDNS_ADVERTISED_SIZE)
+					edns.udp_size = EDNS_FRAG_SIZE_IP4;
+				else	edns.udp_size = EDNS_ADVERTISED_SIZE;
+			}
+		} else {
+			edns.udp_size = EDNS_ADVERTISED_SIZE;
+		}
 		edns.bits = 0;
 		if(sq->dnssec & EDNS_DO)
 			edns.bits = EDNS_DO;
@@ -1564,6 +1576,20 @@ serviced_udp_callback(struct comm_point* c, void* arg, int error,
 			 * by EDNS. */
 			sq->status = serviced_query_UDP_EDNS;
 		}
+		if(sq->status == serviced_query_UDP_EDNS) {
+			/* fallback to 1480/1280 */
+			sq->status = serviced_query_UDP_EDNS_FRAG;
+			log_name_addr(VERB_ALGO, "try edns1xx0", sq->qbuf+10,
+				&sq->addr, sq->addrlen);
+			if(!serviced_udp_send(sq, c->buffer)) {
+				serviced_callbacks(sq, NETEVENT_CLOSED, c, rep);
+			}
+			return 0;
+		}
+		if(sq->status == serviced_query_UDP_EDNS_FRAG) {
+			/* fragmentation size did not fix it */
+			sq->status = serviced_query_UDP_EDNS;
+		}
 		sq->retry++;
 		if(!(rto=infra_rtt_update(outnet->infra, &sq->addr, sq->addrlen,
 			-1, sq->last_rtt, (uint32_t)now.tv_sec)))
@@ -1589,7 +1615,8 @@ serviced_udp_callback(struct comm_point* c, void* arg, int error,
 		return 0;
 	}
 	if(!fallback_tcp) {
-	    if(sq->status == serviced_query_UDP_EDNS 
+	    if( (sq->status == serviced_query_UDP_EDNS 
+	        ||sq->status == serviced_query_UDP_EDNS_FRAG)
 		&& (LDNS_RCODE_WIRE(ldns_buffer_begin(c->buffer)) 
 			== LDNS_RCODE_FORMERR || LDNS_RCODE_WIRE(
 			ldns_buffer_begin(c->buffer)) == LDNS_RCODE_NOTIMPL)) {
diff --git a/services/outside_network.h b/services/outside_network.h
index 493e43010..1ee2f1015 100644
--- a/services/outside_network.h
+++ b/services/outside_network.h
@@ -274,6 +274,11 @@ struct service_callback {
 	void* cb_arg;
 };
 
+/** fallback size for fragmentation for EDNS in IPv4 */
+#define EDNS_FRAG_SIZE_IP4 1480
+/** fallback size for EDNS in IPv6, fits one fragment with ip6-tunnel-ids */
+#define EDNS_FRAG_SIZE_IP6 1260
+
 /**
  * Query service record.
  * Contains query and destination. UDP, TCP, EDNS are all tried.
@@ -314,7 +319,9 @@ struct serviced_query {
 		/** probe to test noEDNS0 (EDNS gives FORMERRorNOTIMP) */
 		serviced_query_UDP_EDNS_fallback,
 		/** probe to test TCP noEDNS0 (EDNS gives FORMERRorNOTIMP) */
-		serviced_query_TCP_EDNS_fallback
+		serviced_query_TCP_EDNS_fallback,
+		/** send UDP query with EDNS1480 (or 1280) */
+		serviced_query_UDP_EDNS_FRAG
 	} 	
 		/** variable with current status */ 
 		status;