From: Mark Andrews <marka@isc.org>
Date: Fri, 1 Nov 2024 02:54:52 +0000 (+1100)
Subject: Fix dual-stack-servers
X-Git-Tag: ondrej/lock-free-qpzone-reads-v1~23^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f98a8331aab5e26266f66be4d974da2522f1d2e1;p=thirdparty%2Fbind9.git

Fix dual-stack-servers

Named was stopping nameserver address resolution attempts too soon
when dual stack servers are configured.  Dual stack servers are
used when there are *not* addresses for the server in a particular
address family so find->status == DNS_ADB_NOMOREADDRESSES is not a
sufficient stopping condition when dual stack servers are available.
Call fctx_try to see if the alternate servers can be used.
---

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index 73d4815163f..262cb51b685 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -2932,13 +2932,17 @@ fctx_finddone(void *arg) {
 		} else {
 			fctx->findfail++;
 			if (atomic_load_acquire(&fctx->pending) == 0) {
-				/*
-				 * We've got nothing else to wait for
-				 * and don't know the answer.  There's
-				 * nothing to do but fail the fctx.
-				 */
 				FCTX_ATTR_CLR(fctx, FCTX_ATTR_ADDRWAIT);
-				want_done = true;
+				if (!ISC_LIST_EMPTY(fctx->res->alternates)) {
+					want_try = true;
+				} else {
+					/*
+					 * We've got nothing else to wait for
+					 * and don't know the answer.  There's
+					 * nothing to do but fail the fctx.
+					 */
+					want_done = true;
+				}
 			}
 		}
 	}