BUG/MINOR: action: do-resolve now use cached response
As reported by David Birdsong on the ML, the HTTP action do-resolve does
not use the DNS cache.
Actually, the action is "registred" to the resolution for said name to
be resolved and wait until an other requester triggers the it. Once the
resolution is finished, then the action is updated with the result.
To trigger this, you must have a server with runtime DNS resolution
enabled and run a do-resolve action with the same fqdn AND they use the
same resolvers section.
This patch fixes this behavior by ensuring the resolution associated to
the action has a valid answer which is not considered as expired. If
those conditions are valid, then we can use it (it's the "cache").
Backport status: 2.0
(cherry picked from commit 7264dfe9495a7bfd784b8964508e4204b7e077af)
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/src/dns.c b/src/dns.c
index f8cafb5..41600c0 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -2150,8 +2150,13 @@
struct dns_resolution *resolution;
struct sample *smp;
char *fqdn;
+ struct dns_requester *req;
+ struct dns_resolvers *resolvers;
+ struct dns_resolution *res;
+ int exp;
/* we have a response to our DNS resolution */
+ use_cache:
if (s->dns_ctx.dns_requester && s->dns_ctx.dns_requester->resolution != NULL) {
resolution = s->dns_ctx.dns_requester->resolution;
if (resolution->step == RSLV_STEP_RUNNING) {
@@ -2211,6 +2216,22 @@
s->dns_ctx.parent = rule;
dns_link_resolution(s, OBJ_TYPE_STREAM, 0);
+
+ /* Check if there is a fresh enough response in the cache of our associated resolution */
+ req = s->dns_ctx.dns_requester;
+ if (!req || !req->resolution) {
+ dns_trigger_resolution(s->dns_ctx.dns_requester);
+ return ACT_RET_YIELD;
+ }
+ res = req->resolution;
+ resolvers = res->resolvers;
+
+ exp = tick_add(res->last_resolution, resolvers->hold.valid);
+ if (resolvers->t && res->status == RSLV_STATUS_VALID && tick_isset(res->last_resolution)
+ && !tick_is_expired(exp, now_ms)) {
+ goto use_cache;
+ }
+
dns_trigger_resolution(s->dns_ctx.dns_requester);
return ACT_RET_YIELD;
}