Unknown error during service discovery

[nitrogenlogic]

This may be a bug in Avahi's libdnssd compatibility wrapper, though the avahi-browse utility is able to browse and resolve services without issue.

When a service on the network has a description ending with a period, service resolution fails with the following error:

DNSSD Error: DNSSD::UnknownError - DNSSD operation failed with unrecognized error code: -65537:
 /var/lib/gems/1.9.1/gems/dnssd-2.0/lib/dnssd/service.rb:163:in `_process'
 /var/lib/gems/1.9.1/gems/dnssd-2.0/lib/dnssd/service.rb:163:in `process'
 /var/lib/gems/1.9.1/gems/dnssd-2.0/lib/dnssd/service.rb:257:in `resolve'
 my_code.rb:137:in `block (2 levels) in start_network_browser'
 /var/lib/gems/1.9.1/gems/dnssd-2.0/lib/dnssd/service.rb:164:in `process'
 /var/lib/gems/1.9.1/gems/dnssd-2.0/lib/dnssd/service.rb:66:in `browse'
 /var/lib/gems/1.9.1/gems/dnssd-2.0/lib/dnssd.rb:178:in `run'
 /var/lib/gems/1.9.1/gems/dnssd-2.0/lib/dnssd.rb:86:in `browse!'
 my_code.rb:130:in `block in start_network_browser'

It appears the error is generated by DNSServiceProcessResult() on line 227 of ext/service.c: https://github.com/tenderlove/dnssd/blob/master/ext/dnssd/service.c#L227

I noticed the issue when my discovery code started crashing whenever a particular computer was turned on. That computer had a service with the following Avahi service descriptor: Removing the period from the field works around the issue, but is not a solution.

<service-group>
    <name replace-wildcards="yes">HTTP Server on %h.</name>
    <service>
        <type>_http._tcp</type>
        <port>80</port>
    </service>
</service-group>

If this is a bug in Avahi, please feel free to pass this bug report to them. I'm running Ubuntu 11.04, Avahi compatibility layer version 0.6.30-0ubuntu2, ruby 1.9.2p0, dnssd gem 2.0.