Add UNKNOWN option for REFRESH_HOSTNAME

src/config.c

@@ -438,6 +438,11 @@ void read_FTLconf(void)
  config.refresh_hostnames = REFRESH_NONE;
  logg(" REFRESH_HOSTNAMES: Not periodically refreshing names");
  }
+ else if(buffer != NULL && strcasecmp(buffer, "UNKNOWN") == 0)
+ {
+ config.refresh_hostnames = REFRESH_UNKNOWN;
+ logg(" REFRESH_HOSTNAMES: Only refreshing recently active clients with unknown hostnames");
+ }
  else
  {
  config.refresh_hostnames = REFRESH_IPV4_ONLY;

src/enums.h

@@ -145,6 +145,7 @@ enum events {
  RELOAD_GRAVITY,
  RELOAD_PRIVACY_LEVEL,
  RERESOLVE_HOSTNAMES,
+ RERESOLVE_HOSTNAMES_FORCE,
  REIMPORT_ALIASCLIENTS,
  PARSE_NEIGHBOR_CACHE,
  EVENTS_MAX
@@ -153,6 +154,7 @@ enum events {
 enum refresh_hostnames {
  REFRESH_ALL,
  REFRESH_IPV4_ONLY,
+ REFRESH_UNKNOWN,
  REFRESH_NONE
 } __attribute__ ((packed));
 

src/events.c

@@ -92,6 +92,8 @@ static const char *eventtext(const enum events event)
  return "RELOAD_PRIVACY_LEVEL";
  case RERESOLVE_HOSTNAMES:
  return "RERESOLVE_HOSTNAMES";
+ case RERESOLVE_HOSTNAMES_FORCE:
+ return "RERESOLVE_HOSTNAMES_FORCE";
  case REIMPORT_ALIASCLIENTS:
  return "REIMPORT_ALIASCLIENTS";
  case PARSE_NEIGHBOR_CACHE:

src/resolve.c

@@ -350,7 +350,7 @@ static size_t resolveAndAddHostname(size_t ippos, size_t oldnamepos)
 }
 
 // Resolve client host names
-static void resolveClients(const bool onlynew)
+static void resolveClients(const bool onlynew, const bool force_refreshing)
 {
  const time_t now = time(NULL);
  // Lock counter access here, we use a copy in the following loop
@@ -386,7 +386,7 @@ static void resolveClients(const bool onlynew)
 
  // Only try to resolve host names of clients which were recently active if we are re-resolving
  // Limit for a "recently active" client is two hours ago
- if(onlynew == false && client->lastQuery < now - 2*60*60)
+ if(!force_refreshing && !onlynew && client->lastQuery < now - 2*60*60)
  {
  if(config.debug & DEBUG_RESOLVER)
  {
@@ -401,7 +401,7 @@ static void resolveClients(const bool onlynew)
 
  // If onlynew flag is set, we will only resolve new clients
  // If not, we will try to re-resolve all known clients
- if(onlynew && !newflag)
+ if(!force_refreshing && onlynew && !newflag)
  {
  if(config.debug & DEBUG_RESOLVER)
  {
@@ -419,15 +419,27 @@ static void resolveClients(const bool onlynew)
  IPv6 = true;
 
  // If we're in refreshing mode (onlynew == false), we skip clients if
- // either IPv4-only or none is selected
+ // 1. We should not refresh any hostnames
+ // 2. We should only refresh IPv4 client, but this client is IPv6
+ // 3. We should only refresh unknown hostnames, but leave
+ // existing ones as they are
  if(onlynew == false &&
- (config.refresh_hostnames == REFRESH_NONE ||
- (config.refresh_hostnames == REFRESH_IPV4_ONLY && IPv6)))
+ (config.refresh_hostnames == REFRESH_NONE ||
+ (config.refresh_hostnames == REFRESH_IPV4_ONLY && IPv6) ||
+ (config.refresh_hostnames == REFRESH_UNKNOWN && oldnamepos != 0)))
  {
  if(config.debug & DEBUG_RESOLVER)
  {
- logg("Skipping client %s (%s) because it should not be refreshed",
- getstr(ippos), getstr(oldnamepos));
+ const char *reason = "N/A";
+ if(config.refresh_hostnames == REFRESH_NONE)
+ reason = "Not refreshing any hostnames";
+ else if(config.refresh_hostnames == REFRESH_IPV4_ONLY)
+ reason = "Only refreshing IPv4 names";
+ else if(config.refresh_hostnames == REFRESH_UNKNOWN)
+ reason = "Looking only for unknown hostnames";
+
+ logg("Skipping client %s (%s) because it should not be refreshed: %s",
+ getstr(ippos), getstr(oldnamepos), reason);
  }
  skipped++;
  continue;
@@ -559,7 +571,8 @@ void *DNSclient_thread(void *val)
  if(resolver_ready && (time(NULL) % RESOLVE_INTERVAL == 0))
  {
  // Try to resolve new client host names (onlynew=true)
- resolveClients(true);
+ // We're not forcing refreshing here
+ resolveClients(true, false);
  // Try to resolve new upstream destination host names (onlynew=true)
  resolveUpstreams(true);
  // Prevent immediate re-run of this routine
@@ -572,11 +585,18 @@ void *DNSclient_thread(void *val)
  set_event(RERESOLVE_HOSTNAMES); // done below
  }
 
+ bool force_refreshing = false;
+ if(get_and_clear_event(RERESOLVE_HOSTNAMES_FORCE))
+ {
+ set_event(RERESOLVE_HOSTNAMES); // done below
+ force_refreshing = true;
+ }
+
  // Process resolver related event queue elements
  if(get_and_clear_event(RERESOLVE_HOSTNAMES))
  {
  // Try to resolve all client host names (onlynew=false)
- resolveClients(false);
+ resolveClients(false, force_refreshing);
  // Try to resolve all upstream destination host names (onlynew=false)
  resolveUpstreams(false);
  // Prevent immediate re-run of this routine

src/signals.c

@@ -283,7 +283,9 @@ static void SIGRT_handler(int signum, siginfo_t *si, void *unused)
  else if(rtsig == 4)
  {
  // Re-resolve all clients and forward destinations
- set_event(RERESOLVE_HOSTNAMES);
+ // Force refreshing hostnames according to
+ // REFRESH_HOSTNAMES config option
+ set_event(RERESOLVE_HOSTNAMES_FORCE);
  }
  else if(rtsig == 5)
  {