Add documentation for common dnsmasq warnings

[yubiuser]

In the upcoming Pi-hole version, the diagnosis system will also show dnsmasq warnings. To reduce user confusion and support requests, we should add common dnsmasq warnings and their interpretation to the documentation

[DL6ER]

These are the possible warnings:

src/dnsmasq/auth.c:704
		  my_syslog(LOG_WARNING, _("ignoring zone transfer request from %s"), daemon->addrbuff);
src/dnsmasq/bpf.c:1713
	   my_syslog(LOG_WARNING, _("Unknown protocol version from route socket"));
src/dnsmasq/dnsmasq.c:10559
	    my_syslog(LOG_WARNING, _("cache size greater than 10000 may cause performance issues, and is unlikely to be useful."));
src/dnsmasq/dnsmasq.c:10571
    my_syslog(LOG_WARNING, "chown of PID file %s failed: %s", daemon->runfile, strerror(chown_warn));
src/dnsmasq/dnsmasq.c:10627
    my_syslog(LOG_WARNING, _("warning: failed to change owner of %s: %s"), 
	      daemon->log_file, strerror(log_err));
src/dnsmasq/dnsmasq.c:10632
    my_syslog(LOG_WARNING, _("setting --bind-interfaces option because of OS limitations"));
src/dnsmasq/dnsmasq.c:10645
	my_syslog(LOG_WARNING, _("warning: interface %s does not currently exist"), if_tmp->name);
src/dnsmasq/dnsmasq.c:10650
	my_syslog(LOG_WARNING, _("warning: ignoring resolv-file flag because no-resolv is set"));
src/dnsmasq/dnsmasq.c:10653
	my_syslog(LOG_WARNING, _("warning: no upstream servers configured"));
src/dnsmasq/dnsmasq.c:10686
    my_syslog(LOG_WARNING, netlink_warn);
src/dnsmasq/dnsmasq.c:11231
	my_syslog(LOG_WARNING, _("script process killed by signal %d"), ev.data);
src/dnsmasq/dnsmasq.c:11235
	my_syslog(LOG_WARNING, _("script process exited with status %d"), ev.data);
src/dnsmasq/dnsmasq.c:11358
	  my_syslog(LOG_WARNING, _("failed to access %s: %s"), res->name, strerror(errno));
src/dnsmasq/dnsmasq.c:11399
	      my_syslog(LOG_WARNING, _("no servers found in %s, will retry"), latest->name);
src/dnsmasq/dnssec.c:14950
      my_syslog(LOG_WARNING, _("Insecure DS reply received for %s, check domain configuration and upstream DNS server DNSSEC support"), name);
src/dnsmasq/forward.c:18523
	  my_syslog(LOG_WARNING, _("discarding DNS reply: subnet option mismatch"));
src/dnsmasq/forward.c:18590
      my_syslog(LOG_WARNING, _("nameserver %s refused to do a recursive query"), daemon->namebuff);
src/dnsmasq/forward.c:18635
	  my_syslog(LOG_WARNING, _("possible DNS-rebind attack detected: %s"), daemon->namebuff);
src/dnsmasq/forward.c:19007
      my_syslog(LOG_WARNING, _("reducing DNS packet size for nameserver %s to %d"), daemon->addrbuff, SAFE_PKTSZ);
src/dnsmasq/forward.c:19322
	      my_syslog(LOG_WARNING, _("Ignoring query from non-local network"));
src/dnsmasq/forward.c:19888
	  my_syslog(LOG_WARNING, _("Ignoring query from non-local network"));
src/dnsmasq/forward.c:20508
	my_syslog(LOG_WARNING, _("Maximum number of concurrent DNS queries reached (max: %d)"), daemon->ftabsize);
src/dnsmasq/forward.c:20510
	my_syslog(LOG_WARNING, _("Maximum number of concurrent DNS queries to %s reached (max: %d)"), domain, daemon->ftabsize);
src/dnsmasq/log.c:23747
		  my_syslog(LOG_WARNING, _("overflow: %d log entries lost"), e);
src/dnsmasq/network.c:25534
	my_syslog(LOG_WARNING, s, daemon->addrbuff, strerror(errno));
src/dnsmasq/network.c:25870
		my_syslog(LOG_WARNING, 
			  _("LOUD WARNING: listening on %s may accept requests via interfaces other than %s"),
			  daemon->addrbuff, iface->name);
src/dnsmasq/network.c:25878
    my_syslog(LOG_WARNING, _("LOUD WARNING: use --bind-dynamic rather than --bind-interfaces to avoid DNS amplification attacks via these interface(s)")); 
src/dnsmasq/network.c:25887
      my_syslog(LOG_WARNING, _("warning: using interface %s instead"), iface->name);
src/dnsmasq/network.c:25896
      my_syslog(LOG_WARNING, _("warning: no addresses found for interface %s"), intname->intr);
src/dnsmasq/network.c:26232
	  my_syslog(LOG_WARNING, _("ignoring nameserver %s - local interface"), daemon->namebuff);
src/dnsmasq/network.c:26242
	  my_syslog(LOG_WARNING, 
		    _("ignoring nameserver %s - cannot make/bind socket: %s"),
		    daemon->namebuff, strerror(errno));
src/dnsmasq/tables.c:41725
      my_syslog(LOG_WARNING, _("IPset: error: %s"), pfr_strerror(errno));
src/dnsmasq/tables.c:41757
      my_syslog(LOG_WARNING, _("warning: DIOCR%sADDRS: %s"), ( remove ? "DEL" : "ADD" ), pfr_strerror(errno));

generated using this small awk script (grep isn't enough because of multi-line matches above)

#!/bin/bash
awk '{
  if ($0 ~ /\(LOG_WARNING,/) {
    triggered=1;
    print FILENAME ":" NR;
  }
  if (triggered) {
     print;
     if ($0 ~ /\);/) {
	triggered=0;
     }
  }
}' src/dnsmasq/*

[AJ]

What do we do about these warnings? I'm not sure if they're documented anywhere in terms of handling or their impact. Not sure how to make the warnings go away (besides "deleting" them)

Please ignore. Found it at https://docs.pi-hole.net/ftldns/dnsmasq_warn/