Do not reschedule requests on expired sockets.

src/dns_private.h

@@ -105,6 +105,7 @@ struct rdns_io_channel {
  struct rdns_server *srv;
  struct rdns_resolver *resolver;
  int sock; /**< persistent socket */
+ bool active;
  void *async_io; /** async opaque ptr */
  struct rdns_request *requests; /**< requests in flight */
  uint64_t uses;

src/resolver.c

@@ -285,6 +285,10 @@ rdns_process_read (int fd, void *arg)
  REF_RELEASE (req);
  }
  }
+ else {
+ /* Still want to increase uses */
+ ioc->uses ++;
+ }
 }
 
 void
@@ -293,8 +297,13 @@ rdns_process_timer (void *arg)
  struct rdns_request *req = (struct rdns_request *)arg;
  struct rdns_reply *rep;
  int r;
+ bool renew = false;
+ struct rdns_resolver *resolver;
+ struct rdns_server *serv = NULL;
 
  req->retransmits --;
+ resolver = req->resolver;
+
  if (req->retransmits == 0) {
  UPSTREAM_FAIL (req->io->srv, time (NULL));
  rep = rdns_make_reply (req, DNS_RC_TIMEOUT);
@@ -306,7 +315,29 @@ rdns_process_timer (void *arg)
  return;
  }
 
- r = rdns_send_request (req, req->io->sock, false);
+ if (!req->io->active) {
+ /* Do not reschedule IO requests on inactive sockets */
+ rdns_debug ("reschedule request with id: %d", (int)req->id);
+ rdns_request_unschedule (req);
+ REF_RELEASE (req->io);
+
+ UPSTREAM_SELECT_ROUND_ROBIN (resolver->servers, serv);
+
+ if (serv == NULL) {
+ rdns_warn ("cannot find suitable server for request");
+ rep = rdns_make_reply (req, DNS_RC_SERVFAIL);
+ req->state = RDNS_REQUEST_REPLIED;
+ req->func (rep, req->arg);
+ REF_RELEASE (req);
+ }
+
+ /* Select random IO channel */
+ req->io = serv->io_channels[ottery_rand_uint32 () % serv->io_cnt];
+ req->io->uses ++;
+ renew = true;
+ }
+
+ r = rdns_send_request (req, req->io->sock, renew);
  if (r == 0) {
  /* Retransmit one more time */
  req->async->del_timer (req->async->data,
@@ -363,13 +394,15 @@ rdns_process_ioc_refresh (void *arg)
  continue;
  }
  nioc->srv = serv;
+ nioc->active = true;
  nioc->resolver = resolver;
  nioc->async_io = resolver->async->add_read (resolver->async->data,
  nioc->sock, nioc);
  REF_INIT_RETAIN (nioc, rdns_ioc_free);
  serv->io_channels[i] = nioc;
  rdns_debug ("scheduled io channel for server %s to be refreshed after "
  "%lu usages", serv->name, (unsigned long)ioc->uses);
+ ioc->active = false;
  REF_RELEASE (ioc);
  }
  }
@@ -532,6 +565,7 @@ rdns_resolver_init (struct rdns_resolver *resolver)
  for (i = 0; i < serv->io_cnt; i ++) {
  ioc = calloc (1, sizeof (struct rdns_io_channel));
  ioc->sock = rdns_make_client_socket (serv->name, serv->port, SOCK_DGRAM);
+ ioc->active = true;
  if (ioc->sock == -1) {
  return false;
  }