kernel/linux.git/include/net/ip6_fib.h, branch v6.12.80

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

2026-04-02T11:09:35+00:00

[ Upstream commit 4be7b99c253f0c85a255cc1db7127ba3232dfa30 ] 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 Signed-off-by: Sasha Levin

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

net/ipv6: Revert remove expired routes with a separated list of routes

2023-12-21T08:01:30+00:00

This reverts commit 3dec89b14d37ee635e772636dad3f09f78f1ab87. The commit has some race conditions given how expires is managed on a fib6_info in relation to gc start, adding the entry to the gc list and setting the timer value leading to UAF. Revert the commit and try again in a later release. Fixes: 3dec89b14d37 ("net/ipv6: Remove expired routes with a separated list of routes") Cc: Kui-Feng Lee Signed-off-by: David Ahern Reviewed-by: Eric Dumazet Link: https://lore.kernel.org/r/20231219030243.25687-1-dsahern@kernel.org Signed-off-by: Paolo Abeni

net: fib: avoid warn splat in flow dissector

2023-08-31T10:33:03+00:00

New skbs allocated via nf_send_reset() have skb->dev == NULL. fib*_rules_early_flow_dissect helpers already have a 'struct net' argument but its not passed down to the flow dissector core, which will then WARN as it can't derive a net namespace to use: WARNING: CPU: 0 PID: 0 at net/core/flow_dissector.c:1016 __skb_flow_dissect+0xa91/0x1cd0 [..] ip_route_me_harder+0x143/0x330 nf_send_reset+0x17c/0x2d0 [nf_reject_ipv4] nft_reject_inet_eval+0xa9/0xf2 [nft_reject_inet] nft_do_chain+0x198/0x5d0 [nf_tables] nft_do_chain_inet+0xa4/0x110 [nf_tables] nf_hook_slow+0x41/0xc0 ip_local_deliver+0xce/0x110 .. Cc: Stanislav Fomichev Cc: David Ahern Cc: Ido Schimmel Fixes: 812fa71f0d96 ("netfilter: Dissect flow after packet mangling") Link: https://bugzilla.kernel.org/show_bug.cgi?id=217826 Signed-off-by: Florian Westphal Reviewed-by: Ido Schimmel Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20230830110043.30497-1-fw@strlen.de Signed-off-by: Paolo Abeni

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

2023-08-16T11:26:43+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. Signed-off-by: Kui-Feng Lee Reviewed-by: David Ahern Signed-off-by: David S. Miller

ipv6: Remove in6addr_any alternatives.

2023-03-29T07:22:52+00:00

Some code defines the IPv6 wildcard address as a local variable and use it with memcmp() or ipv6_addr_equal(). Let's use in6addr_any and ipv6_addr_any() instead. Signed-off-by: Kuniyuki Iwashima Reviewed-by: Mark Bloch Reviewed-by: David Ahern Signed-off-by: David S. Miller

net: dst: Prevent false sharing vs. dst_entry:: __refcnt

2023-03-29T01:52:22+00:00

dst_entry::__refcnt is highly contended in scenarios where many connections happen from and to the same IP. The reference count is an atomic_t, so the reference count operations have to take the cache-line exclusive. Aside of the unavoidable reference count contention there is another significant problem which is caused by that: False sharing. perf top identified two affected read accesses. dst_entry::lwtstate and rtable::rt_genid. dst_entry:__refcnt is located at offset 64 of dst_entry, which puts it into a seperate cacheline vs. the read mostly members located at the beginning of the struct. That prevents false sharing vs. the struct members in the first 64 bytes of the structure, but there is also dst_entry::lwtstate which is located after the reference count and in the same cache line. This member is read after a reference count has been acquired. struct rtable embeds a struct dst_entry at offset 0. struct dst_entry has a size of 112 bytes, which means that the struct members of rtable which follow the dst member share the same cache line as dst_entry::__refcnt. Especially rtable::rt_genid is also read by the contexts which have a reference count acquired already. When dst_entry:__refcnt is incremented or decremented via an atomic operation these read accesses stall. This was found when analysing the memtier benchmark in 1:100 mode, which amplifies the problem extremly. Move the rt[6i]_uncached[_list] members out of struct rtable and struct rt6_info into struct dst_entry to provide padding and move the lwtstate member after that so it ends up in the same cache line. The resulting improvement depends on the micro-architecture and the number of CPUs. It ranges from +20% to +120% with a localhost memtier/memcached benchmark. [ tglx: Rearrange struct ] Signed-off-by: Wangyang Guo Signed-off-by: Arjan van de Ven Signed-off-by: Thomas Gleixner Reviewed-by: Eric Dumazet Reviewed-by: David Ahern Link: https://lore.kernel.org/r/20230323102800.042297517@linutronix.de Signed-off-by: Jakub Kicinski