From: Vladimír Čunát <vladimir.cunat@nic.cz>
Date: Fri, 29 Aug 2025 06:27:51 +0000 (+0200)
Subject: on FORMERR, retry without EDNS even if EDNS was in that reply
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=refs%2Fheads%2Fformerr-retry;p=thirdparty%2Fknot-resolver.git

on FORMERR, retry without EDNS even if EDNS was in that reply
---

diff --git a/lib/selection.c b/lib/selection.c
index 6ba549cd3..3770c0e54 100644
--- a/lib/selection.c
+++ b/lib/selection.c
@@ -657,6 +657,9 @@ void error(struct kr_query *qry, struct address_state *addr_state,
 		qry->server_selection.local_state->timeouts++;
 		server_timeout(qry, transport, addr_state, &qry->request->ctx->cache);
 		break;
+	case KR_SELECTION_FORMERR_EDNS:
+		/* It's quite possible that the server does not support EDNS,
+		 * but violated this MUST.  It won't hurt to try. */
 	case KR_SELECTION_FORMERR:
 		if (qry->flags.NO_EDNS) {
 			addr_state->broken = true;
@@ -664,9 +667,6 @@ void error(struct kr_query *qry, struct address_state *addr_state,
 			qry->flags.NO_EDNS = true;
 		}
 		break;
-	case KR_SELECTION_FORMERR_EDNS:
-		addr_state->broken = true;
-		break;
 	case KR_SELECTION_MISMATCHED:
 		if (qry->flags.NO_0X20 && qry->flags.TCP) {
 			addr_state->broken = true;