linux-stable.git/include/net/ip6_fib.h, branch linux-7.1.y

ipv6: remove ipv6_stub infrastructure completely

2026-03-29T18:21:24+00:00

As IPv6 is built-in only and there are no more users of ipv6_stub, the
ipv6_stub is now entirely obsolete.

Remove all the code related to the definition, initialization and usage.

Signed-off-by: Fernando Fernandez Mancera 
Tested-by: Ricardo B. Marlière 
Link: https://patch.msgid.link/20260325120928.15848-11-fmancera@suse.de
Signed-off-by: Jakub Kicinski

ipv6: prepare headers for ipv6_stub removal

2026-03-29T18:21:23+00:00

In preparation for dropping ipv6_stub and converting its users to direct
function calls, introduce static inline dummy functions and fallback
macros in the IPv6 networking headers. In addition, introduce checks on
fib6_nh_init(), ip6_dst_lookup_flow() and ip6_fragment() to avoid a
crash due to ipv6.disable=1 set during booting. The other functions are
safe as they cannot be called with ipv6.disable=1 set.

These fallbacks ensure that when CONFIG_IPV6 is completely disabled,
there are no compiling or linking errors due to code paths not guarded
by preprocessor macro IS_ENABLED(CONFIG_IPV6).

In addition, export ndisc_send_na(), ip6_route_input() and
ip6_fragment().

Signed-off-by: Fernando Fernandez Mancera 
Tested-by: Ricardo B. Marlière 
Link: https://patch.msgid.link/20260325120928.15848-6-fmancera@suse.de
Signed-off-by: Jakub Kicinski

ipv6: replace IS_BUILTIN(CONFIG_IPV6) with IS_ENABLED(CONFIG_IPV6)

2026-03-29T18:21:23+00:00

As IPv6 is built-in only, it does not make sense to continue using
IS_BUILTIN(CONFIG_IPV6). Therefore, replace it with IS_ENABLED() when
necessary and drop it if it isn't valid anymore.

Notice that there is still one instance related to ICMPv6, as it
requires more changes it will be handle separately.

Signed-off-by: Fernando Fernandez Mancera 
Tested-by: Ricardo B. Marlière 
Acked-by: Martin KaFai Lau 
Link: https://patch.msgid.link/20260325120928.15848-4-fmancera@suse.de
Signed-off-by: Jakub Kicinski

ipv6: Don't remove permanent routes with exceptions from tb6_gc_hlist.

2026-03-23T23:59:31+00:00

The cited commit mechanically put fib6_remove_gc_list()
just after every fib6_clean_expires() call.

When a temporary route is promoted to a permanent route,
there may already be exception routes tied to it.

If fib6_remove_gc_list() removes the route from tb6_gc_hlist,
such exception routes will no longer be aged.

Let's replace fib6_remove_gc_list() with a new helper
fib6_may_remove_gc_list() and use fib6_age_exceptions() there.

Note that net->ipv6 is only compiled when CONFIG_IPV6 is
enabled, so fib6_{add,remove,may_remove}_gc_list() are guarded.

Fixes: 5eb902b8e719 ("net/ipv6: Remove expired routes with a separated list of routes.")
Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20260320072317.2561779-3-kuniyu@google.com
Signed-off-by: Jakub Kicinski

ipv6: Defer fib6_purge_rt() in fib6_add_rt2node() to fib6_add().

2025-04-24T07:29:56+00:00

The next patch adds per-nexthop spinlock which protects nh->f6i_list.

When rt->nh is not NULL, fib6_add_rt2node() will be called under the lock.
fib6_add_rt2node() could call fib6_purge_rt() for another route, which
could holds another nexthop lock.

Then, deadlock could happen between two nexthops.

Let's defer fib6_purge_rt() after fib6_add_rt2node().

Signed-off-by: Kuniyuki Iwashima 
Acked-by: Paolo Abeni 
Link: https://patch.msgid.link/20250418000443.43734-14-kuniyu@amazon.com
Signed-off-by: Paolo Abeni

ipv6: use READ_ONCE()/WRITE_ONCE() on fib6_table->fib_seq

2024-10-11T22:35:05+00:00

Using RTNL to protect ops->fib_rules_seq reads seems a big hammer.

Writes are protected by RTNL.
We can use READ_ONCE() when reading it.

Constify 'struct net' argument of fib6_tables_seq_read() and
fib6_rules_seq_read().

Signed-off-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20241009184405.3752829-4-edumazet@google.com
Signed-off-by: Jakub Kicinski

ipv6: introduce dst_rt6_info() helper

2024-04-29T12:32:01+00:00

Instead of (struct rt6_info *)dst casts, we can use :

 #define dst_rt6_info(_ptr) \
         container_of_const(_ptr, struct rt6_info, dst)

Some places needed missing const qualifiers :

ip6_confirm_neigh(), ipv6_anycast_destination(),
ipv6_unicast_destination(), has_gateway()

v2: added missing parts (David Ahern)

Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

ipv6: use call_rcu_hurry() in fib6_info_release()

2024-04-29T09:03:51+00:00

This is a followup of commit c4e86b4363ac ("net: add two more
call_rcu_hurry()")

fib6_info_destroy_rcu() is calling nexthop_put() or fib6_nh_release()

We must not delay it too much or risk unregister_netdevice/ref_tracker
traces because references to netdev are not released in time.

This should speedup device/netns dismantles when CONFIG_RCU_LAZY=y

Signed-off-by: Eric Dumazet 
Reviewed-by: Jiri Pirko 
Reviewed-by: David Ahern 
Signed-off-by: David S. Miller

net/ipv6: Remove expired routes with a separated list of routes.

2024-02-12T10:24:12+00:00

FIB6 GC walks trees of fib6_tables to remove expired routes. Walking a tree
can be expensive if the number of routes in a table is big, even if most of
them are permanent. Checking routes in a separated list of routes having
expiration will avoid this potential issue.

Reviewed-by: David Ahern 
Signed-off-by: Kui-Feng Lee 
Signed-off-by: David S. Miller

net/ipv6: resolve warning in ip6_fib.c

2024-01-24T01:22:23+00:00

In some configurations, the 'iter' variable in function
fib6_repair_tree() is unused, resulting the following warning when
compiled with W=1.

    net/ipv6/ip6_fib.c:1781:6: warning: variable 'iter' set but not used [-Wunused-but-set-variable]
     1781 |         int iter = 0;
	  |             ^

It is unclear what is the advantage of this RT6_TRACE() macro[1], since
users can control pr_debug() in runtime, which is better than at
compilation time. pr_debug() has no overhead when disabled.

Remove the RT6_TRACE() in favor of simple pr_debug() helpers.

[1] Link: https://lore.kernel.org/all/ZZwSEJv2HgI0cD4J@gmail.com/
Signed-off-by: Breno Leitao 
Reviewed-by: David Ahern 
Link: https://lore.kernel.org/r/20240122181955.2391676-2-leitao@debian.org
Signed-off-by: Jakub Kicinski