[pulseaudio-discuss] incomplete IPv6 support in pa_socket_client_new_string()

[Hajime Fujita]

Tanu Kaskinen wrote:
> On Wed, 2014-11-05 at 22:29 -0600, Hajime Fujita wrote:
>> Hi Tanu,
>>
>> Thank you for your comment and sorry for the late reply.
>>
>> Tanu Kaskinen wrote:
>>> On Tue, 2014-10-21 at 00:49 -0500, Hajime Fujita wrote:
>>>> Hello,
>>>>
>>>> I'm currently working on IPv6 support for the raop module [1].
>>>>
>>>> During the work I found a potential issue in
>>>> pa_socket_client_new_string() (in pulsecore/socket-client.c) as pointed
>>>> out in [1].
>>>>
>>>> It does not work as expected when an IPv6 address string like
>>>> "2001:db8::1" is passed as the "name" parameter. This is because the
>>>> name parameter is passed to pa_parse_address(), which thinks the last
>>>> colon as a separator between hostname (or address) and a port number. To
>>>> prevent pa_parse_address() from doing this, an IPv6 address must be
>>>> bracketed with "[]" (e.g. "[2001:db8::1]").
>>>>
>>>> I'm wondering what would be the best solution for this situation.
>>>> a. Modify callers: callers of pa_socket_client_new_string() must add
>>>> brackets to IPv6 addresses.
>>>> b. Modify pa_socket_client_new_string(): if an IPv6 address is given as
>>>> the name parameter, it will be bracketed before being passed to
>>>> pa_parse_address().
>>>>
>>>> Any opinions or suggestions?
>>>
>>> I think it makes more sense to fix this in the callers of
>>> pa_socket_client_new_string(). It would be good to also add a comment in
>>> socket-client.h saying that the name parameter can include also the port
>>> using the usual syntax, and for that reason IPv6 addresses must be
>>> enclosed in brackets.
>>>
>>
>> Do you have any justification behind this?
>
> Yes, sorry for leaving it out from my answer. The justification: I think
> you can't actually implement suggestion b, because there's no way you
> can figure out in pa_socket_client_new_string() whether
> "1234::1234:1234" contains only an IP address or an IP address and a
> port.

Well my justification for option b was:
if the caller wants to pass "addr:port" style string to 
pa_socket_client_new_string(), "addr" must be surrounded by brackets for 
the very reason you described.
So, if pa_socket_client_new_string() sees a string like 
"1234::1234:1234", I thought it would be safe to interpret it as an IPv6 
address alone, not including port.


Thanks,
Hajime