From: Christopher Faulet <cfaulet@haproxy.com>
Date: Thu, 11 Mar 2021 08:36:05 +0000 (+0100)
Subject: MINOR: resolvers: Use milliseconds for cached items in resolver responses
X-Git-Tag: v2.4-dev12~17
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=55c1c4053f70bf53adfcd5067fa959e20f2b44fe;p=thirdparty%2Fhaproxy.git

MINOR: resolvers: Use milliseconds for cached items in resolver responses

The last time when an item was seen in a resolver responses is now stored in
milliseconds instead of seconds. This avoid some corner-cases at the
edges. This also simplifies time comparisons.
---

diff --git a/include/haproxy/resolvers-t.h b/include/haproxy/resolvers-t.h
index ba373707cf..96874aabe2 100644
--- a/include/haproxy/resolvers-t.h
+++ b/include/haproxy/resolvers-t.h
@@ -113,7 +113,7 @@ struct resolv_answer_item {
 	uint16_t        data_len;                    /* number of bytes in target below */
 	struct sockaddr address;                     /* IPv4 or IPv6, network format */
 	char            target[DNS_MAX_NAME_SIZE+1]; /* Response data: SRV or CNAME type target */
-	time_t          last_seen;                   /* When was the answer was last seen */
+	unsigned int    last_seen;                   /* When was the answer was last seen */
 	struct resolv_answer_item *ar_item;          /* pointer to a RRset from the additional section, if exists */
 	struct list     list;
 };
diff --git a/src/resolvers.c b/src/resolvers.c
index 38c3588ca7..8c09b7b09c 100644
--- a/src/resolvers.c
+++ b/src/resolvers.c
@@ -582,7 +582,7 @@ static void resolv_check_response(struct resolv_resolution *res)
 		struct resolv_answer_item *ar_item = item->ar_item;
 
 		/* clean up obsolete Additional record */
-		if (ar_item && (ar_item->last_seen + resolvers->hold.obsolete / 1000) < now.tv_sec) {
+		if (ar_item && tick_is_lt(tick_add(ar_item->last_seen, resolvers->hold.obsolete), now_ms)) {
 			/* Cleaning up the AR item will trigger an extra DNS  resolution, except if the SRV
 			 * item is also obsolete.
 			 */
@@ -591,7 +591,7 @@ static void resolv_check_response(struct resolv_resolution *res)
 		}
 
 		/* Remove obsolete items */
-		if ((item->last_seen + resolvers->hold.obsolete / 1000) < now.tv_sec) {
+		if (tick_is_lt(tick_add(item->last_seen, resolvers->hold.obsolete), now_ms)) {
 			if (item->type != DNS_RTYPE_SRV)
 				goto rm_obselete_item;
 
@@ -901,6 +901,7 @@ static int resolv_validate_dns_response(unsigned char *resp, unsigned char *bufe
 
 		/* initialization */
 		answer_record->ar_item = NULL;
+		answer_record->last_seen = TICK_ETERNITY;
 
 		offset = 0;
 		len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE, &offset, 0);
@@ -1096,12 +1097,12 @@ static int resolv_validate_dns_response(unsigned char *resp, unsigned char *bufe
 		}
 
 		if (found == 1) {
-			tmp_record->last_seen = now.tv_sec;
+			tmp_record->last_seen = now_ms;
 			pool_free(resolv_answer_item_pool, answer_record);
 			answer_record = NULL;
 		}
 		else {
-			answer_record->last_seen = now.tv_sec;
+			answer_record->last_seen = now_ms;
 			answer_record->ar_item = NULL;
 			LIST_ADDQ(&r_res->answer_list, &answer_record->list);
 			answer_record = NULL;
@@ -1151,6 +1152,7 @@ static int resolv_validate_dns_response(unsigned char *resp, unsigned char *bufe
 		answer_record = pool_alloc(resolv_answer_item_pool);
 		if (answer_record == NULL)
 			goto invalid_resp;
+		answer_record->last_seen = TICK_ETERNITY;
 
 		offset = 0;
 		len = resolv_read_name(resp, bufend, reader, tmpname, DNS_MAX_NAME_SIZE, &offset, 0);
@@ -1277,12 +1279,12 @@ static int resolv_validate_dns_response(unsigned char *resp, unsigned char *bufe
 		}
 
 		if (found == 1) {
-			tmp_record->ar_item->last_seen = now.tv_sec;
+			tmp_record->ar_item->last_seen = now_ms;
 			pool_free(resolv_answer_item_pool, answer_record);
 			answer_record = NULL;
 		}
 		else {
-			answer_record->last_seen = now.tv_sec;
+			answer_record->last_seen = now_ms;
 			answer_record->ar_item = NULL;
 
 			// looking for the SRV record in the response list linked to this additional record