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Unlock IPV6CTL_DEFMCASTHLIM case of ip6_sysctl()
On Thu, Jul 24, 2025 at 09:42:32PM +0300, Vitaliy Makkoveev wrote:
> Only ip6_setmoptions() needs to use cached value. Nothing critical if
> the destination interface was changed and ip6_output() will load
> `ip6_defmcasthlim' once again to re-initialize `ip6' header.
OK bluhm@
> Index: sys/netinet6/in6_proto.c
> ===================================================================
> RCS file: /cvs/src/sys/netinet6/in6_proto.c,v
> retrieving revision 1.141
> diff -u -p -r1.141 in6_proto.c
> --- sys/netinet6/in6_proto.c 24 Jul 2025 18:02:19 -0000 1.141
> +++ sys/netinet6/in6_proto.c 24 Jul 2025 18:31:27 -0000
> @@ -352,9 +352,9 @@ int ip6_forwarding = 0; /* [a] no forwar
> int ip6_mforwarding = 0; /* no multicast forwarding unless ... */
> int ip6_multipath = 0; /* [a] no using multipath routes unless ... */
> int ip6_sendredirects = 1; /* [a] */
> -int ip6_defhlim = IPV6_DEFHLIM; /* [a] */
> -int ip6_defmcasthlim = IPV6_DEFAULT_MULTICAST_HOPS;
> -int ip6_maxfragpackets = 200; /* [a] */
> +int ip6_defhlim = IPV6_DEFHLIM; /* [a] */
> +int ip6_defmcasthlim = IPV6_DEFAULT_MULTICAST_HOPS; /* [a] */
> +int ip6_maxfragpackets = 200; /* [a] */
> int ip6_maxfrags = 200;
> int ip6_log_interval = 5; /* [a] */
> int ip6_hdrnestlimit = 10; /* [a] appropriate? */
> Index: sys/netinet6/ip6_input.c
> ===================================================================
> RCS file: /cvs/src/sys/netinet6/ip6_input.c,v
> retrieving revision 1.285
> diff -u -p -r1.285 ip6_input.c
> --- sys/netinet6/ip6_input.c 24 Jul 2025 18:02:19 -0000 1.285
> +++ sys/netinet6/ip6_input.c 24 Jul 2025 18:31:27 -0000
> @@ -1452,10 +1452,10 @@ const struct sysctl_bounded_args ipv6ctl
> { IPV6CTL_HDRNESTLIMIT, &ip6_hdrnestlimit, 0, 100 },
> { IPV6CTL_DAD_COUNT, &ip6_dad_count, 0, 10 },
> { IPV6CTL_AUTO_FLOWLABEL, &ip6_auto_flowlabel, 0, 1 },
> + { IPV6CTL_DEFMCASTHLIM, &ip6_defmcasthlim, 0, 255 },
> };
>
> const struct sysctl_bounded_args ipv6ctl_vars[] = {
> - { IPV6CTL_DEFMCASTHLIM, &ip6_defmcasthlim, 0, 255 },
> { IPV6CTL_USE_DEPRECATED, &ip6_use_deprecated, 0, 1 },
> { IPV6CTL_MAXFRAGS, &ip6_maxfrags, 0, 1000 },
> { IPV6CTL_MFORWARDING, &ip6_mforwarding, 0, 1 },
> @@ -1575,6 +1575,7 @@ ip6_sysctl(int *name, u_int namelen, voi
> case IPV6CTL_HDRNESTLIMIT:
> case IPV6CTL_DAD_COUNT:
> case IPV6CTL_AUTO_FLOWLABEL:
> + case IPV6CTL_DEFMCASTHLIM:
> return (sysctl_bounded_arr(
> ipv6ctl_vars_unlocked, nitems(ipv6ctl_vars_unlocked),
> name, namelen, oldp, oldlenp, newp, newlen));
> Index: sys/netinet6/ip6_output.c
> ===================================================================
> RCS file: /cvs/src/sys/netinet6/ip6_output.c,v
> retrieving revision 1.301
> diff -u -p -r1.301 ip6_output.c
> --- sys/netinet6/ip6_output.c 8 Jul 2025 00:47:41 -0000 1.301
> +++ sys/netinet6/ip6_output.c 24 Jul 2025 18:31:27 -0000
> @@ -420,7 +420,7 @@ reroute:
> if (im6o != NULL)
> ip6->ip6_hlim = im6o->im6o_hlim;
> else
> - ip6->ip6_hlim = ip6_defmcasthlim;
> + ip6->ip6_hlim = atomic_load_int(&ip6_defmcasthlim);
> }
>
> #ifdef IPSEC
> @@ -1879,6 +1879,7 @@ ip6_setmoptions(int optname, struct ip6_
> struct ip6_moptions *im6o = *im6op;
> struct in6_multi_mship *imm;
> struct proc *p = curproc; /* XXX */
> + int ip6_defmcasthlim_local = atomic_load_int(&ip6_defmcasthlim);
>
> if (im6o == NULL) {
> /*
> @@ -1890,7 +1891,7 @@ ip6_setmoptions(int optname, struct ip6_
> return (ENOBUFS);
> *im6op = im6o;
> im6o->im6o_ifidx = 0;
> - im6o->im6o_hlim = ip6_defmcasthlim;
> + im6o->im6o_hlim = ip6_defmcasthlim_local;
> im6o->im6o_loop = IPV6_DEFAULT_MULTICAST_LOOP;
> LIST_INIT(&im6o->im6o_memberships);
> }
> @@ -1937,7 +1938,7 @@ ip6_setmoptions(int optname, struct ip6_
> if (optval < -1 || optval >= 256)
> error = EINVAL;
> else if (optval == -1)
> - im6o->im6o_hlim = ip6_defmcasthlim;
> + im6o->im6o_hlim = ip6_defmcasthlim_local;
> else
> im6o->im6o_hlim = optval;
> break;
> @@ -2137,7 +2138,7 @@ ip6_setmoptions(int optname, struct ip6_
> * structure.
> */
> if (im6o->im6o_ifidx == 0 &&
> - im6o->im6o_hlim == ip6_defmcasthlim &&
> + im6o->im6o_hlim == ip6_defmcasthlim_local &&
> im6o->im6o_loop == IPV6_DEFAULT_MULTICAST_LOOP &&
> LIST_EMPTY(&im6o->im6o_memberships)) {
> free(*im6op, M_IPMOPTS, sizeof(**im6op));
> @@ -2169,7 +2170,7 @@ ip6_getmoptions(int optname, struct ip6_
> hlim = mtod(m, u_int *);
> m->m_len = sizeof(u_int);
> if (im6o == NULL)
> - *hlim = ip6_defmcasthlim;
> + *hlim = atomic_load_int(&ip6_defmcasthlim);
> else
> *hlim = im6o->im6o_hlim;
> return (0);
> @@ -2178,7 +2179,7 @@ ip6_getmoptions(int optname, struct ip6_
> loop = mtod(m, u_int *);
> m->m_len = sizeof(u_int);
> if (im6o == NULL)
> - *loop = ip6_defmcasthlim;
> + *loop = atomic_load_int(&ip6_defmcasthlim);
> else
> *loop = im6o->im6o_loop;
> return (0);
Unlock IPV6CTL_DEFMCASTHLIM case of ip6_sysctl()