Re: [PATCH v2 1/9] conf: Support CIDR notation for -a/--address option

[David Gibson <david@gibson.dropbear.id.au>]

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On Wed, Jan 21, 2026 at 07:06:10PM -0500, Jon Maloy wrote:
> On 2026-01-19 00:02, David Gibson wrote:
> > On Sun, Jan 18, 2026 at 05:16:04PM -0500, Jon Maloy wrote:
[snip]
> > > +/**
> > > + * conf_addr_prefix_len() - Parse address with optional prefix length
> > > + * @arg:	Address string, optionally with /prefix_len suffix (modified)
> > > + * @addr:	Output for parsed address
> > > + * @prefix_len: Output for prefix length (0 if not specified)
> > > + *
> > > + * Return: AF_INET for IPv4, AF_INET6 for IPv6, -1 on error
> > > + */
> > > +static int conf_addr_prefix_len(char *arg, union inany_addr *addr,
> > > +				int *prefix_len)
> > > +{
> > > +	char *slash;
> > > +
> > > +	*prefix_len = 0;
> > > +
> > > +	/* Check for /prefix_len suffix */
> > > +	slash = strchr(arg, '/');
> > > +	if (slash) {
> > > +		unsigned long len;
> > > +		char *end;
> > > +
> > > +		*slash = '\0';
> > > +		errno = 0;
> > > +		len = strtoul(slash + 1, &end, 10);
> > > +		if (errno || *end)
> > > +			return -1;
> > > +
> > > +		*prefix_len = len;
> > > +	}
> > > +
> > > +	if (!inany_prefix_pton(arg, addr, prefix_len))
> > > +		return -1;
> > 
> > Oh, sorry, I wasn't clear.  My idea was that inany_prefix_pton() would
> > handle the parsing (strchr(), strtoul() etc.) of the prefix length
> > internally, rather than doing that here then adjusting it in there.
> 
> Ok. So I basically eliminate conf_addr_perfix_len() and replace it with
> a inany_prefix_pton() which does all the job. Makes sense.

Yes.

> Regarding the prefix length adjustment: if I give some address in one of the
> following two formats:
> 192.168.1.1/24
> or
> ::ffff:192.168.1.1/120
> 
> they will both be stored in the array in exactly the same
> format, as ::ffff:192.168.1.1.

Yes.

> It makes little sense to use two different prefix lengths just
> because the user happened to use some specific format, and would
> only create problems for anybody trying to access that entry later.
> I think this one *should* be adjusted.

Absolutely, but they should all be adjusted to the IPv6 form, not the
IPv4 form.

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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