Re: [PATCH v3 08/25] fwd: Allow FWD_DUAL_STACK_ANY flag to be passed directly to fwd_rule_add()

[Stefano Brivio <sbrivio@redhat.com>]

Nits:

On Mon, 23 Mar 2026 18:37:15 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> fwd_rule_add() takes a flags parameter, but it only allows the FWD_WEAK
> and FWD_SCAN flags to be specified there.  It doesn't allow the
> FWD_DUAL_STACK_ANY flag to be set, instead expecting a [*] address to be
> indicated by passing NULL as @addr.
> 
> However, for upcoming dynamic rule updates, it's more convenient to be able
> to explicitly pass FWD_DUAL_STACK_ANY along with an address of ::.  Allow
> that mode of calling.
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>  fwd.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/fwd.c b/fwd.c
> index 3395a28e..d73b7ca7 100644
> --- a/fwd.c
> +++ b/fwd.c
> @@ -362,18 +362,21 @@ void fwd_rule_add(struct fwd_table *fwd, uint8_t proto, uint8_t flags,
>  		  in_port_t first, in_port_t last, in_port_t to)
>  {
>  	/* Flags which can be set from the caller */
> -	const uint8_t allowed_flags = FWD_WEAK | FWD_SCAN;
> +	const uint8_t allowed_flags = FWD_WEAK | FWD_SCAN | FWD_DUAL_STACK_ANY;
>  	unsigned num = (unsigned)last - first + 1;
>  	struct fwd_rule *new;
>  	unsigned i, port;
>  
>  	assert(!(flags & ~allowed_flags));
> -

Spurious change, I think? The extra newline here looks good for
readability. Maybe we should group the second assert with this one?

>  	if (fwd->count >= ARRAY_SIZE(fwd->rules))
>  		die("Too many port forwarding ranges");
>  	if ((fwd->sock_count + num) > ARRAY_SIZE(fwd->socks))
>  		die("Too many listening sockets");
>  
> +	/* Passing a non-wildcard address with DUAL_STACK_ANY  is a bug */

Extra whitespace after DUAL_STACK_ANY.

> +	assert(!(flags & FWD_DUAL_STACK_ANY) || !addr ||
> +	       inany_equals(addr, &inany_any6));
> +
>  	/* Check for any conflicting entries */
>  	for (i = 0; i < fwd->count; i++) {
>  		char newstr[INANY_ADDRSTRLEN], rulestr[INANY_ADDRSTRLEN];

-- 
Stefano