From: Michał Kępień <michal@isc.org>
Date: Mon, 25 May 2020 12:34:56 +0000 (+0200)
Subject: Remove fctx->reason and a misleading log message
X-Git-Tag: v9.17.2~60^2~5
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=949d9a3ea4ea6048b619c6af27815113f17de5e8;p=thirdparty%2Fbind9.git

Remove fctx->reason and a misleading log message

The following message:

    success resolving '<name>' (in '<domain>'?) after reducing the advertised EDNS UDP packet size to 512 octets

can currently be logged even if the EDNS UDP buffer size advertised in
queries sent to a given server had already been set to 512 octets before
the fetch context was created (e.g. due to the server responding
intermittently).  In other words, this log message may be misleading as
lowering the advertised EDNS UDP buffer size may not be the actual cause
of <name> being successfully resolved.  Remove the log message in
question to prevent confusion.

As this log message is the only existing user of the "reason" field in
struct fetchctx, remove that field as well, along with all the code
related to it.
---

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index a518a1f613f..f73f8b70f6c 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -369,12 +369,6 @@ struct fetchctx {
 	 */
 	unsigned int nqueries; /* Bucket lock. */
 
-	/*%
-	 * The reason to print when logging a successful
-	 * response to a query.
-	 */
-	const char *reason;
-
 	/*%
 	 * Random numbers to use for mixing up server addresses.
 	 */
@@ -1748,25 +1742,6 @@ fctx_sendevents(fetchctx_t *fctx, isc_result_t result, int line) {
 	}
 }
 
-static inline void
-log_edns(fetchctx_t *fctx) {
-	char domainbuf[DNS_NAME_FORMATSIZE];
-
-	if (fctx->reason == NULL) {
-		return;
-	}
-
-	/*
-	 * We do not know if fctx->domain is the actual domain the record
-	 * lives in or a parent domain so we have a '?' after it.
-	 */
-	dns_name_format(&fctx->domain, domainbuf, sizeof(domainbuf));
-	isc_log_write(dns_lctx, DNS_LOGCATEGORY_EDNS_DISABLED,
-		      DNS_LOGMODULE_RESOLVER, ISC_LOG_INFO,
-		      "success resolving '%s' (in '%s'?) after %s", fctx->info,
-		      domainbuf, fctx->reason);
-}
-
 static void
 fctx_done(fetchctx_t *fctx, isc_result_t result, int line) {
 	dns_resolver_t *res;
@@ -1780,10 +1755,6 @@ fctx_done(fetchctx_t *fctx, isc_result_t result, int line) {
 	res = fctx->res;
 
 	if (result == ISC_R_SUCCESS) {
-		/*%
-		 * Log any deferred EDNS timeout messages.
-		 */
-		log_edns(fctx);
 		no_response = true;
 		if (fctx->qmin_warning != ISC_R_SUCCESS) {
 			isc_log_write(dns_lctx, DNS_LOGCATEGORY_LAME_SERVERS,
@@ -1799,7 +1770,6 @@ fctx_done(fetchctx_t *fctx, isc_result_t result, int line) {
 	}
 
 	fctx->qmin_warning = ISC_R_SUCCESS;
-	fctx->reason = NULL;
 
 	fctx_stopqueries(fctx, no_response, age_untried);
 
@@ -2624,8 +2594,6 @@ resquery_send(resquery_t *query) {
 							  query->addrinfo);
 			} else if (tried->count >= 2U) {
 				query->options |= DNS_FETCHOPT_EDNS512;
-				fctx->reason = "reducing the advertised EDNS "
-					       "UDP packet size to 512 octets";
 			}
 		}
 	}
@@ -4583,7 +4551,6 @@ fctx_timeout(isc_task_t *task, isc_event_t *event) {
 	inc_stats(fctx->res, dns_resstatscounter_querytimeout);
 
 	if (event->ev_type == ISC_TIMEREVENT_LIFE) {
-		fctx->reason = NULL;
 		fctx_done(fctx, ISC_R_TIMEDOUT, __LINE__);
 	} else {
 		isc_result_t result;
@@ -4996,7 +4963,6 @@ fctx_create(dns_resolver_t *res, const dns_name_t *name, dns_rdatatype_t type,
 	atomic_init(&fctx->attributes, 0);
 	fctx->spilled = false;
 	fctx->nqueries = 0;
-	fctx->reason = NULL;
 	fctx->rand_buf = 0;
 	fctx->rand_bits = 0;
 	fctx->timeout = false;