From: Alexander Bluhm <bluhm@openbsd.org>
Subject: Re: Unlock IPCTL_ARPDOWN case of ip_sysctl()
To: Vitaliy Makkoveev <mvs@openbsd.org>
Cc: tech@openbsd.org
Date: Thu, 17 Jul 2025 11:23:46 +0200

On Wed, Jul 16, 2025 at 01:45:40AM +0300, Vitaliy Makkoveev wrote:
> The last one of `ipctl_vars'. Also was marked as [a], loaded only once
> at arpresolve(), so just use atomic_load_int() to get value.

OK bluhm@

> Index: sys/netinet/if_ether.c
> ===================================================================
> RCS file: /cvs/src/sys/netinet/if_ether.c,v
> retrieving revision 1.275
> diff -u -p -r1.275 if_ether.c
> --- sys/netinet/if_ether.c	15 Jul 2025 22:12:49 -0000	1.275
> +++ sys/netinet/if_ether.c	15 Jul 2025 22:41:49 -0000
> @@ -447,7 +447,7 @@ arpresolve(struct ifnet *ifp, struct rte
>  				refresh = 1;
>  			else {
>  				reject = RTF_REJECT;
> -				rt->rt_expire += arpt_down;
> +				rt->rt_expire += atomic_load_int(&arpt_down);
>  				la->la_asked = 0;
>  				la->la_refreshed = 0;
>  				atomic_sub_int(&la_hold_total,
> Index: sys/netinet/ip_input.c
> ===================================================================
> RCS file: /cvs/src/sys/netinet/ip_input.c,v
> retrieving revision 1.420
> diff -u -p -r1.420 ip_input.c
> --- sys/netinet/ip_input.c	15 Jul 2025 22:12:49 -0000	1.420
> +++ sys/netinet/ip_input.c	15 Jul 2025 22:41:49 -0000
> @@ -111,7 +111,7 @@ int	ip_maxqueue = 300;			/* [a] */
>  int	ip_frags = 0;				/* [q] */
>  
>  #ifndef SMALL_KERNEL
> -const struct sysctl_bounded_args ipctl_vars_unlocked[] = {
> +const struct sysctl_bounded_args ipctl_vars[] = {
>  	{ IPCTL_FORWARDING, &ip_forwarding, 0, 2 },
>  	{ IPCTL_SENDREDIRECTS, &ip_sendredirects, 0, 1 },
>  	{ IPCTL_DIRECTEDBCAST, &ip_directedbcast, 0, 1 },
> @@ -126,9 +126,6 @@ const struct sysctl_bounded_args ipctl_v
>  	{ IPCTL_IPPORT_MAXQUEUE, &ip_maxqueue, 0, 10000 },
>  	{ IPCTL_MFORWARDING, &ipmforwarding, 0, 1 },
>  	{ IPCTL_ARPTIMEOUT, &arpt_keep, 0, INT_MAX },
> -};
> -
> -const struct sysctl_bounded_args ipctl_vars[] = {
>  	{ IPCTL_ARPDOWN, &arpt_down, 0, INT_MAX },
>  };
>  #endif /* SMALL_KERNEL */
> @@ -1832,29 +1829,9 @@ ip_sysctl(int *name, u_int namelen, void
>  		}
>  
>  		return (error);
> -	case IPCTL_FORWARDING:
> -	case IPCTL_SENDREDIRECTS:
> -	case IPCTL_DIRECTEDBCAST:
> -#ifdef MROUTING
> -	case IPCTL_MRTPROTO:
> -#endif
> -	case IPCTL_DEFTTL:
> -	case IPCTL_IPPORT_FIRSTAUTO:
> -	case IPCTL_IPPORT_LASTAUTO:
> -	case IPCTL_IPPORT_HIFIRSTAUTO:
> -	case IPCTL_IPPORT_HILASTAUTO:
> -	case IPCTL_IPPORT_MAXQUEUE:
> -	case IPCTL_MFORWARDING:
> -	case IPCTL_ARPTIMEOUT:
> -		return (sysctl_bounded_arr(
> -		    ipctl_vars_unlocked, nitems(ipctl_vars_unlocked),
> -		    name, namelen, oldp, oldlenp, newp, newlen));
>  	default:
> -		NET_LOCK();
> -		error = sysctl_bounded_arr(ipctl_vars, nitems(ipctl_vars),
> -		    name, namelen, oldp, oldlenp, newp, newlen);
> -		NET_UNLOCK();
> -		return (error);
> +		return (sysctl_bounded_arr(ipctl_vars, nitems(ipctl_vars),
> +		    name, namelen, oldp, oldlenp, newp, newlen));
>  	}
>  	/* NOTREACHED */
>  }