Merge "pjproject_bundled: Prevent SERVFAIL from marking name server bad" into 14

third-party/pjproject/patches/0004-resolver.c-Prevent-SERVFAIL-from-marking-name-server.patch

@@ -0,0 +1,48 @@
+From a5efddbe9151e9ad99279e59566c86f8bc27d3a9 Mon Sep 17 00:00:00 2001
+From: George Joseph <gjoseph@digium.com>
+Date: Wed, 7 Sep 2016 13:10:57 -0600
+Subject: [PATCH] resolver.c:  Prevent SERVFAIL from marking name server bad
+
+A name server that returns "Server Failure" is indicating only that
+the server couldn't process that particular request.  We should NOT
+assume that the name server is incapable of serving other requests.
+
+Here's the scenario we've been encountering...
+
+* 2 local name servers configured in resolv.conf.
+* An OPTIONS request causes a request for A and AAAA records to go out
+  to both nameservers.
+* The A responses both come back successfully resolved.
+* Because of an issue at some upstream nameserver, the AAAA responses
+  for that particular query come back as "SERVFAIL" from both local
+  name servers.
+* Both local servers are marked as bad and no further queries can be
+  sent until the 60 second ttl expires.  Only previously cached results
+  can be used.
+* In this case, 60 seconds is just enough time for another OPTIONS
+  request to go out to the same host so the cycle repeats.
+
+We could set the bad ttl really low but that also affects REFUSED and
+NOTAUTH which probably DO signal a real server issue.  Besides, even
+a really low bad ttl would be an issue on a pbx.
+---
+ pjlib-util/src/pjlib-util/resolver.c | 3 +--
+ 1 file changed, 1 insertion(+), 2 deletions(-)
+
+diff --git a/pjlib-util/src/pjlib-util/resolver.c b/pjlib-util/src/pjlib-util/resolver.c
+index d277e4f..540f88f 100644
+--- a/pjlib-util/src/pjlib-util/resolver.c
++++ b/pjlib-util/src/pjlib-util/resolver.c
+@@ -1384,8 +1384,7 @@ static void report_nameserver_status(pj_dns_resolver *resolver,
+ 	q_id = (pj_uint32_t)-1;
+     }
+ 
+-    if (!pkt || rcode == PJ_DNS_RCODE_SERVFAIL ||
+-	        rcode == PJ_DNS_RCODE_REFUSED ||
++    if (!pkt || rcode == PJ_DNS_RCODE_REFUSED ||
+ 	        rcode == PJ_DNS_RCODE_NOTAUTH) 
+     {
+ 	is_good = PJ_FALSE;
+-- 
+2.7.4
+