From 361ed1b4a6ba5dc3db488b4a22253d1508a7ac77 Mon Sep 17 00:00:00 2001
From: Tom Wilkie <tom@weave.works>
Date: Tue, 14 Jul 2015 13:51:29 +0000
Subject: [PATCH] Resolve unqualified domains in the weave.local domain.

---
 nameserver/dns.go                | 24 +++++++++++++++++++-----
 test/230_dns_unqualified_test.sh | 12 ++++++------
 test/config.sh                   |  9 +++------
 3 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/nameserver/dns.go b/nameserver/dns.go
index af437897..c2868aa2 100644
--- a/nameserver/dns.go
+++ b/nameserver/dns.go
@@ -129,7 +129,11 @@ func (d *DNSServer) handleLocal(defaultMaxResponseSize int) func(dns.ResponseWri
 			return
 		}
 
-		hostname := req.Question[0].Name
+		hostname := dns.Fqdn(req.Question[0].Name)
+		if strings.Count(hostname, ".") == 1 {
+			hostname = hostname + d.domain
+		}
+
 		addrs := d.ns.Lookup(hostname)
 
 		response := dns.Msg{}
@@ -139,7 +143,7 @@ func (d *DNSServer) handleLocal(defaultMaxResponseSize int) func(dns.ResponseWri
 		response.Answer = make([]dns.RR, len(addrs))
 
 		header := dns.RR_Header{
-			Name:   hostname,
+			Name:   req.Question[0].Name,
 			Rrtype: dns.TypeA,
 			Class:  dns.ClassINET,
 			Ttl:    d.ttl,
@@ -211,15 +215,25 @@ func (d *DNSServer) handleReverse(client *dns.Client, defaultMaxResponseSize int
 
 func (d *DNSServer) handleRecursive(client *dns.Client, defaultMaxResponseSize int) func(dns.ResponseWriter, *dns.Msg) {
 	return func(w dns.ResponseWriter, req *dns.Msg) {
-		d.ns.debugf("recursive cdrequest: %+v", *req)
+		d.ns.debugf("recursive request: %+v", *req)
+
+		// Resolve unqualified names locally
+		if len(req.Question) == 1 && req.Question[0].Qtype == dns.TypeA {
+			hostname := dns.Fqdn(req.Question[0].Name)
+			if strings.Count(hostname, ".") == 1 {
+				d.handleLocal(defaultMaxResponseSize)(w, req)
+				return
+			}
+		}
+
 		for _, server := range d.upstream.Servers {
 			response, _, err := client.Exchange(req, fmt.Sprintf("%s:%s", server, d.upstream.Port))
 			if err != nil || response == nil {
-				d.ns.debugf("network error trying %s (%s)", server, err)
+				d.ns.debugf("error trying %s: %v", server, err)
 				continue
 			}
 			if response.Rcode != dns.RcodeSuccess && !response.Authoritative {
-				d.ns.debugf("network error trying %s (%s)", server, err)
+				d.ns.debugf("non-authoritative error trying %s: %v", server, response.Rcode)
 				continue
 			}
 			d.ns.debugf("response: %+v", response)
diff --git a/test/230_dns_unqualified_test.sh b/test/230_dns_unqualified_test.sh
index 146af9c3..0283d73f 100755
--- a/test/230_dns_unqualified_test.sh
+++ b/test/230_dns_unqualified_test.sh
@@ -18,12 +18,12 @@ start_container_with_dns $HOST1 $C2/24 --name=c2 -h seetwo.$DOMAIN
 start_container_with_dns $HOST1 $C3/24 --name=c3 --dns-search=$DOMAIN
 container=$(start_container_with_dns $HOST1 $C4/24)
 
-check() {
-  assert "exec_on $HOST1 $1 getent hosts seeone | tr -s ' '" "$C1 $NAME"
-}
+assert_dns_a_record $HOST1 c2           seeone     $C1 $NAME
+assert_dns_a_record $HOST1 c3           seeone     $C1 $NAME
+assert_dns_a_record $HOST1 "$container" seeone     $C1 $NAME
 
-check c2
-check c3
-check "$container"
+# check that unqualified names are automatically qualified for broken resolvers
+weave_on $HOST1 dns-add $C1 c1 -h mysql.weave.local
+assert_dns_a_record $HOST1 c1 mysql $C1
 
 end_suite
diff --git a/test/config.sh b/test/config.sh
index e9e4a49b..ffdfe652 100644
--- a/test/config.sh
+++ b/test/config.sh
@@ -43,10 +43,6 @@ CHECK_ETHWE_UP="grep ^1$ /sys/class/net/ethwe/carrier"
 
 DOCKER_PORT=2375
 
-WEAVEDNS_ARGS="--no-cache"
-[ -n "$DEBUG" ] && WEAVEDNS_ARGS="$WEAVEDNS_ARGS --log-level=debug"
-
-
 upload_executable() {
     host=$1
     file=$2
@@ -182,9 +178,10 @@ assert_no_dns_record() {
     assert_raises "exec_on $host $container getent hosts $name" 2
 }
 
-# assert_dns_a_record <host> <container> <name> <ip>
+# assert_dns_a_record <host> <container> <name> <ip> [<expected_name>]
 assert_dns_a_record() {
-    assert "exec_on $1 $2 getent hosts $3 | tr -s ' '" "$4 $3"
+    exp_name=${5:-$3}
+    assert "exec_on $1 $2 getent hosts $3 | tr -s ' ' | cut -d ' ' -f 1,2" "$4 $exp_name"
 }
 
 # assert_dns_ptr_record <host> <container> <name> <ip>