git: 39dbadb7a410 - main - netlink: Fix IFF_UP flag handling in RTM_NEWLINK's modify_link handler

[Aymeric Wibo]

The branch main has been updated by obiwac:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=39dbadb7a410f3955540041848d669264266e552

commit 39dbadb7a410f3955540041848d669264266e552
Author:     Muhammad Saheed <sah...@freebsd.org>
AuthorDate: 2025-08-18 13:50:08 +0000
Commit:     Aymeric Wibo <obi...@freebsd.org>
CommitDate: 2025-08-18 13:51:10 +0000

    netlink: Fix IFF_UP flag handling in RTM_NEWLINK's modify_link handler
    
    IFF_UP could previously only be unset via RTM_NEWLINK. Requests to set
    IFF_UP, though they succeed, did not actually set the flag.
    
    RTM_NEWLINK messages with ifi_change=0 are treated as
    ifi_change=0xFFFFFFFF, modifying all the link flags (currently IFF_UP
    and IFF_PROMISC) to match the behavior seen on Linux.
    
    Reviewed by:    obiwac, kp, mckusick (mentor)
    Approved by:    obiwac, mckusick (mentor)
    Sponsored by:   Google LLC (GSoC)
    Differential Revision:  https://reviews.freebsd.org/D51871
---
 sys/netlink/route/iface_drivers.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/sys/netlink/route/iface_drivers.c 
b/sys/netlink/route/iface_drivers.c
index 4bf913d9c978..5f605b05f7b8 100644
--- a/sys/netlink/route/iface_drivers.c
+++ b/sys/netlink/route/iface_drivers.c
@@ -82,9 +82,12 @@ _nl_modify_ifp_generic(struct ifnet *ifp, struct 
nl_parsed_link *lattrs,
                }
        }
 
-       if ((lattrs->ifi_change & IFF_UP) && (lattrs->ifi_flags & IFF_UP) == 0) 
{
-               /* Request to down the interface */
-               if_down(ifp);
+       if ((lattrs->ifi_change & IFF_UP) != 0 || lattrs->ifi_change == 0) {
+               /* Request to up or down the interface */
+               if (lattrs->ifi_flags & IFF_UP)
+                       if_up(ifp);
+               else
+                       if_down(ifp);
        }
 
        if (lattrs->ifla_mtu > 0) {
@@ -97,7 +100,8 @@ _nl_modify_ifp_generic(struct ifnet *ifp, struct 
nl_parsed_link *lattrs,
                }
        }
 
-       if (lattrs->ifi_change & IFF_PROMISC) {
+       if ((lattrs->ifi_change & IFF_PROMISC) != 0 ||
+           lattrs->ifi_change == 0) {
                error = ifpromisc(ifp, lattrs->ifi_flags & IFF_PROMISC);
                if (error != 0) {
                        nlmsg_report_err_msg(npt, "unable to set promisc");