Commit 67272a5204 for bind

commit 67272a5204f2dae7aeb86cab3e6d3b72e809aad7
Author: Ondřej Surý <ondrej@isc.org>
Date:   Fri Sep 4 14:41:33 2026 +0200

    Recover from route socket overflow on OpenBSD

    OpenBSD does not fail the read when the route socket buffer overflows;
    it queues an RTM_DESYNC message instead and keeps discarding new
    messages until the buffer has been drained. Treat that message like
    ENOBUFS so the same rescan recovery runs there as on Linux and the
    other BSDs.

diff --git a/lib/ns/interfacemgr.c b/lib/ns/interfacemgr.c
index ac14ac97b5..50c37cf16b 100644
--- a/lib/ns/interfacemgr.c
+++ b/lib/ns/interfacemgr.c
@@ -230,6 +230,7 @@ route_recv(isc_nmhandle_t *handle, isc_result_t eresult, isc_region_t *region,
 	ns_interfacemgr_t *mgr = (ns_interfacemgr_t *)arg;
 	struct MSGHDR *rtm = NULL;
 	size_t rtmlen = 0;
+	bool rtm_desync = false;

 	isc_log_write(NS_LOGCATEGORY_NETWORK, NS_LOGMODULE_INTERFACEMGR,
 		      ISC_LOG_DEBUG(9), "route_recv: %s",
@@ -258,7 +259,21 @@ route_recv(isc_nmhandle_t *handle, isc_result_t eresult, isc_region_t *region,
 			return;
 		}
 #endif /* ifdef RTM_VERSION */
-		break;
+
+#if defined(RTM_DESYNC)
+		/*
+		 * On OpenBSD, the route socket overflow is reported as
+		 * a RTM_DESYNC message, so we need to fall through to
+		 * ISC_R_NORESOURCES.
+		 */
+		if (rtm->rtm_type == RTM_DESYNC) {
+			rtm_desync = true;
+		}
+#endif
+		if (!rtm_desync) {
+			break;
+		}
+		FALLTHROUGH;
 	case ISC_R_NORESOURCES:
 		if (mgr->sctx->interface_auto) {
 			/* There might have been route that we missed */