Re: [PATCH v7 04/13] arp: Check all configured addresses in ARP filtering

[Stefano Brivio <sbrivio@redhat.com>]

On Sun, 12 Apr 2026 20:53:10 -0400
Jon Maloy <jmaloy@redhat.com> wrote:

> As a preparation for handling multiple addresses, we update ignore_arp()
> to check against all addresses in the unified addrs[] array using the
> for_each_addr() macro.
> 
> Signed-off-by: Jon Maloy <jmaloy@redhat.com>
> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> 
> ---
> v3: -Adapted to single-array changes earlier in this series
> v6: -Made loop in ignore_arp() a little more palatable,
>      but not entirely as suggested by David.
> v7: -Curly brackets in ignore_arp(), as suggested by Stefano.
>     -I did not modify the for_each_addr(), macro, as Stefano suggested,
>      since it also would require us to add an extra parameter indicating
>      the array length.
> ---
>  arp.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/arp.c b/arp.c
> index a7fd82f..a3fdeb6 100644
> --- a/arp.c
> +++ b/arp.c
> @@ -42,6 +42,7 @@ static bool ignore_arp(const struct ctx *c,
>  		       const struct arphdr *ah, const struct arpmsg *am)
>  {
>  	const struct guest_addr *a;
> +	union inany_addr addr;
>  
>  	if (ah->ar_hrd != htons(ARPHRD_ETHER)	||
>  	    ah->ar_pro != htons(ETH_P_IP)	||
> @@ -55,11 +56,12 @@ static bool ignore_arp(const struct ctx *c,
>  	    !memcmp(am->sip, am->tip, sizeof(am->sip)))
>  		return true;
>  
> -	/* Don't resolve the guest's assigned address, either. */
> -	a = fwd_get_addr(c, AF_INET, 0, 0);
> -	if (a && !memcmp(am->tip, inany_v4(&a->addr), sizeof(am->tip)))
> -		return true;
> -
> +	/* Don't resolve any of the guest's addresses */
> +	inany_from_af(&addr, AF_INET, am->tip);
> +	for_each_addr(a, c->addrs, c->addr_count, AF_INET) {
> +		if (inany_equals(&addr, &a->addr))
> +			return true;
> +	}

...same here about a lookup function.

>  	return false;
>  }
>  

-- 
Stefano