Re: [PATCH] man/man5/gai.conf: Labels have a label not a precedence

[Alejandro Colomar <alx@kernel.org>]

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Hi Dave,

On Wed, Jan 14, 2026 at 02:26:11PM +0000, Dr. David Alan Gilbert wrote:
> * Dr. David Alan Gilbert (dave@treblig.org) wrote:
> > * Alejandro Colomar (alx@kernel.org) wrote:
> > > Hi David,
> > 
> > Hi Alex,
> 
> Hi Alex,
> > > On Sun, Jan 04, 2026 at 10:04:38PM +0000, dg@treblig.org wrote:
> > > > From: "Dr. David Alan Gilbert" <dave@treblig.org>
> > > > 
> > > > The numeric value on a label entry is a label which is separate
> > > > from the precedences.  Labels are compared with other labels, not
> > > > precedences.
> > > 
> > > Is there any source to verify this?
> > 
> > The two I checked are:
> >   https://datatracker.ietf.org/doc/html/rfc3484#section-2.1
> >     is the RFC itself, and it talks about the Precedence and labels
> > as separate values.  Note how it's talking in terms of:
> > 
> >    If Precedence(A) > Precedence(B), we say that...
> > and
> >    The algorithms prefer to use a source address S with a destination
> >    address D if Label(S) = Label(D).
> > 
> > So it's label compared to label and precedence compared to precedence.
> > 
> > The corresponding bits of glibc are:
> > https://sourceware.org/git/?p=glibc.git;a=blob;f=nss/getaddrinfo.c;h=c0f496f96c752220e68bf0257d9ff1ffc624ebe6;hb=HEAD#l1525
> > 
> > where the label values are compared in Rule 5, and the precedence values
> > are compared in Rule 6.
> 
>   Does that explanation I sent make sense?

Thanks for the ping, and sorry for being slow!

I've verified now, and have applied the patch.  Thanks for the patch and
for the follow-up links and details!


Have a lovely night!
Alex

> 
> Dave
> 
> > Dave
> > 
> > > 
> > > Cheers,
> > > Alex
> > > 
> > > > 
> > > > Rename the field.
> > > > 
> > > > Signed-off-by: Dr. David Alan Gilbert <dave@treblig.org>
> > > > ---
> > > >  man/man5/gai.conf.5 | 4 ++--
> > > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > > 
> > > > diff --git a/man/man5/gai.conf.5 b/man/man5/gai.conf.5
> > > > index 4aff0b0b9..ef330995d 100644
> > > > --- a/man/man5/gai.conf.5
> > > > +++ b/man/man5/gai.conf.5
> > > > @@ -26,7 +26,7 @@ .SH DESCRIPTION
> > > >  .P
> > > >  The keywords currently recognized are:
> > > >  .TP
> > > > -.BI label\~ netmask\~precedence
> > > > +.BI label\~ netmask\~label
> > > >  The value is added to the label table used in the RFC\ 3484 sorting.
> > > >  If any
> > > >  .B label
> > > > @@ -35,7 +35,7 @@ .SH DESCRIPTION
> > > >  All the label definitions
> > > >  of the default table which are to be maintained have to be duplicated.
> > > >  Following the keyword,
> > > > -the line has to contain a network mask and a precedence value.
> > > > +the line has to contain a network mask and a label value.
> > > >  .TP
> > > >  .BI precedence\~ netmask\~precedence
> > > >  This keyword is similar to
> > > > -- 
> > > > 2.52.0
> > > > 
> > > 
> > > -- 
> > > <https://www.alejandro-colomar.es>
> > 
> > 
> > -- 
> >  -----Open up your eyes, open up your mind, open up your code -------   
> > / Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \ 
> > \        dave @ treblig.org |                               | In Hex /
> >  \ _________________________|_____ http://www.treblig.org   |_______/
> -- 
>  -----Open up your eyes, open up your mind, open up your code -------   
> / Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \ 
> \        dave @ treblig.org |                               | In Hex /
>  \ _________________________|_____ http://www.treblig.org   |_______/

-- 
<https://www.alejandro-colomar.es>

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