Re: git: 2f8f892ca344 - main - rtnetlink: Add FreeBSD-specific IFLAF_GROUP support
Date: Mon, 31 Aug 2026 15:23:32 UTC
On Thu, Aug 27, 2026 at 6:28 AM Pouria Mousavizadeh Tehrani
<pouria@freebsd.org> wrote:
>
> The branch main has been updated by pouria:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=2f8f892ca344d884abbed0305886bb532f16368f
>
> commit 2f8f892ca344d884abbed0305886bb532f16368f
> Author: Pouria Mousavizadeh Tehrani <pouria@FreeBSD.org>
> AuthorDate: 2026-08-27 12:43:28 +0000
> Commit: Pouria Mousavizadeh Tehrani <pouria@FreeBSD.org>
> CommitDate: 2026-08-27 13:04:53 +0000
>
> rtnetlink: Add FreeBSD-specific IFLAF_GROUP support
>
> Netlink IFLA_GROUP works with a single group id, in our
> implementation an interface can be joined to multiple groups
> and it works with group name.
> Store interface groups in IFLAF_GROUP attribute.
>
> Reviewed by: glebius, melifaro
> Discussed with: markj
> Differential Revision: https://reviews.freebsd.org/D58643
> ---
> sys/net/if.c | 24 ++++++++++++++++++++++
> sys/net/if_var.h | 2 ++
> sys/netlink/netlink_snl_route_parsers.h | 8 ++++++++
> sys/netlink/route/iface.c | 35 ++++++++++++++++++++++++++++++++-
> sys/netlink/route/interface.h | 1 +
> 5 files changed, 69 insertions(+), 1 deletion(-)
>
> diff --git a/sys/net/if.c b/sys/net/if.c
> index 1c57eb1492c2..644a039c8d25 100644
> --- a/sys/net/if.c
> +++ b/sys/net/if.c
> @@ -1468,6 +1468,30 @@ if_delgroups(struct ifnet *ifp)
> IFNET_WUNLOCK();
> }
>
> +/*
> + * XXX: This KPI should not expose ifg_group. therefore the current
> + * implementation is questionable and may change in the future.
> + */
> +int
> +if_foreach_group(struct ifnet *ifp, if_foreach_group_cb_t cb, void *cb_arg)
> +{
> + struct ifg_list *ifgl;
> + int error;
> +
> + MPASS(cb);
> +
> + error = 0;
> + IFNET_RLOCK();
I'm seeing lock recursion panics under WITNESS if I create and destroy
interfaces with this change. Please see
https://reviews.freebsd.org/D59289 for a proposed fix.
> + CK_STAILQ_FOREACH(ifgl, &ifp->if_groups, ifgl_next) {
> + error = cb(ifgl->ifgl_group, cb_arg);
> + if (error != 0)
> + break;
> + }
> + IFNET_RUNLOCK();
> +
> + return (error);
> +}
> +
> /*
> * Stores all groups from an interface in memory pointed to by ifgr.
> */
> diff --git a/sys/net/if_var.h b/sys/net/if_var.h
> index 9a425fd81054..d3d4b1e2a36c 100644
> --- a/sys/net/if_var.h
> +++ b/sys/net/if_var.h
> @@ -525,6 +525,8 @@ VNET_DECLARE(if_t, loif); /* first loopback interface */
> #define MCDPRINTF(...)
> #endif
>
> +typedef int (*if_foreach_group_cb_t)(struct ifg_group *, void *);
> +int if_foreach_group(if_t, if_foreach_group_cb_t, void *);
> int if_addgroup(if_t, const char *);
> int if_delgroup(if_t, const char *);
> int if_addmulti(if_t, struct sockaddr *, struct ifmultiaddr **);
> diff --git a/sys/netlink/netlink_snl_route_parsers.h b/sys/netlink/netlink_snl_route_parsers.h
> index 10698ca987f3..495dee5ec862 100644
> --- a/sys/netlink/netlink_snl_route_parsers.h
> +++ b/sys/netlink/netlink_snl_route_parsers.h
> @@ -174,6 +174,11 @@ SNL_DECLARE_PARSER_EXT(snl_rtm_route_parser, sizeof(struct rtmsg),
> sizeof(struct snl_parsed_route), _fp_p_route, _nla_p_route,
> _cb_p_route);
>
> +static const struct snl_attr_parser _nla_p_ifgroups[] = {
> + { .type = IFLAF_GROUP, .cb = snl_attr_copy_string, .arg_u32 = sizeof(char[IFNAMSIZ]) },
> +};
> +SNL_DECLARE_ATTR_PARSER_EXT(_ifgroups_parser, sizeof(char[IFNAMSIZ]), _nla_p_ifgroups, NULL);
> +
> /* RTM_<NEW|DEL|GET>LINK message parser */
> struct snl_parsed_link {
> uint32_t ifi_index;
> @@ -191,6 +196,7 @@ struct snl_parsed_link {
> struct rtnl_link_stats64 *ifla_stats64;
> struct nlattr *iflaf_orig_hwaddr;
> struct snl_attr_bitset iflaf_caps;
> + struct snl_parray iflaf_groups;
> };
>
> #define _IN(_field) offsetof(struct ifinfomsg, _field)
> @@ -198,6 +204,8 @@ struct snl_parsed_link {
> static const struct snl_attr_parser _nla_p_link_fbsd[] = {
> { .type = IFLAF_ORIG_HWADDR, .off = _OUT(iflaf_orig_hwaddr), .cb = snl_attr_dup_nla },
> { .type = IFLAF_CAPS, .off = _OUT(iflaf_caps), .cb = snl_attr_get_bitset_c },
> + { .type = IFLAF_GROUP, .off = _OUT(iflaf_groups), .cb = snl_attr_get_parray,
> + .arg = &_ifgroups_parser },
> };
> SNL_DECLARE_ATTR_PARSER(_link_fbsd_parser, _nla_p_link_fbsd);
>
> diff --git a/sys/netlink/route/iface.c b/sys/netlink/route/iface.c
> index 5b6e58a598aa..50dd35b74479 100644
> --- a/sys/netlink/route/iface.c
> +++ b/sys/netlink/route/iface.c
> @@ -204,6 +204,38 @@ get_hwaddr(struct nl_writer *nw, if_t ifp)
> }
> }
>
> +static int
> +dump_group_cb(struct ifg_group *ifg, void *_arg)
> +{
> + struct nl_writer *nw = (struct nl_writer *)_arg;
> + int off, ret = 0;
> +
> + off = nlattr_add_nested(nw, IFLAF_GROUP);
> + if (off == 0)
> + return (ENOMEM);
> +
> + if (!nlattr_add_string(nw, IFLAF_GROUP, ifg->ifg_group))
> + ret = ENOMEM;
> +
> + nlattr_set_len(nw, off);
> + return (ret);
> +}
> +
> +static int
> +dump_group(struct nl_writer *nw, if_t ifp)
> +{
> + int off, ret;
> +
> + off = nlattr_add_nested(nw, IFLAF_GROUP);
> + if (off == 0)
> + return (ENOMEM);
> +
> + ret = if_foreach_group(ifp, dump_group_cb, nw);
> + nlattr_set_len(nw, off);
> +
> + return (ret);
> +}
> +
> static unsigned
> ifp_flags_to_netlink(const if_t ifp)
> {
> @@ -344,7 +376,6 @@ dump_iface(struct nl_writer *nw, if_t ifp, const struct nlmsghdr *hdr,
> /*
> nlattr_add_u32(nw, IFLA_MIN_MTU, 60);
> nlattr_add_u32(nw, IFLA_MAX_MTU, 9000);
> - nlattr_add_u32(nw, IFLA_GROUP, 0);
> */
>
> if (if_getdescr(ifp) != NULL)
> @@ -355,6 +386,8 @@ dump_iface(struct nl_writer *nw, if_t ifp, const struct nlmsghdr *hdr,
> if (off != 0) {
> get_hwaddr(nw, ifp);
> dump_iface_caps(nw, ifp);
> + if (dump_group(nw, ifp) != 0)
> + goto enomem;
>
> nlattr_set_len(nw, off);
> }
> diff --git a/sys/netlink/route/interface.h b/sys/netlink/route/interface.h
> index c018a0adb20d..4394dcfef21d 100644
> --- a/sys/netlink/route/interface.h
> +++ b/sys/netlink/route/interface.h
> @@ -152,6 +152,7 @@ enum {
> IFLAF_ORIG_IFNAME = 1, /* string, original interface name at creation */
> IFLAF_ORIG_HWADDR = 2, /* binary, original hardware address */
> IFLAF_CAPS = 3, /* bitset, interface capabilities */
> + IFLAF_GROUP = 4, /* string, interface group name (multi-attr) */
> __IFLAF_MAX
> };
> #define IFLAF_MAX (__IFLAF_MAX - 1)
>